The brain and the gut are connected from early fetal life. The mother’s exposure to microbial molecules is thought to exert in utero developmental effects on the fetus. These effects could importantly underpin the groundwork for subsequent pathophysiological mechanisms for achieving immunological tolerance and metabolic equilibrium post birth, events that continue through to 3–4 years of age. Furthermore, it is understood that the microbiome promotes cues that instruct the neonate’s mucosal tissues and skin in the language of molecular and cellular biology. Post birth mucosal lymphoid tissue formation and maturation (most probably including the vermiform appendix) is microbiota-encouraged co-establishing the intestinal microbiome with a developing immune system. Intestinal mucosal tissue maturation loops the brain-gut-brain and is postulated to influence mood dispositions via shifts in the intestinal microbiome phyla. A plausible appreciation is that dysregulated pro-inflammatory signals from intestinal resident macrophages could breach the loop by providing adverse mood signals via vagus nerve afferents to the brain. In this commentary, we further suggest that the intestinal resident macrophages act as an upstream traffic controller of translocated microbes and metabolites in order to maintain local neuro-endocrine-immunological equilibrium. When macrophages are overwhelmed through intestinal microbiome and intestinal epithelial cell dysbiosis, pro-inflammatory signals are sustained, which may then lead to mood disorders. The administration of probiotics as an adjunctive medicine co-administered with antidepressant medications in improving depressed mood may have biological and clinical standing. Both the intestines and the brain develop from the same cluster of embryonic tissue that can be traced back to the primitive streak in early vertebrate fetal growth. As such, this grooved structure that forms on day 15 of human development, along the caudal midline of the bilaminar embryonic disc is the first visible sign of gastrulation that will give rise to the ectoderm, mesoderm and endoderm . Such isImmune molecules have been reported to participate in integral functions in the CNS throughout various stages of neural development, including affecting neurogenesis, neuronal migration, axon guidance, synapse formation, activity-dependent refinement of circuits, and synaptic plasticity . For exaIn the intestines there is recognized a tripartite co-operation in order to maintain intestinal steady state homeostasis. This occurs between the intestinal epithelium barrier, the intestinal microbiome and gut mucosal immune cells such as macrophages ,7,8. Macrophages (mononuclear phagocytes) are distributed throughout the body in tissue sites that include for example the intestines, the lung, the liver, and the brain . Macrophhi) are specialized cells that are involved in antigen presentation to T cells that in turn shape the T cell responses generated [In the gut, intestinal resident macrophages  and also express the integrin ligand semaphorin 7A that undergoes contact-dependent interactions with intestinal macrophages. This activity induces the expression of IL-10 that in turn further promotes intestinal homeostasis. Therefore these cumulative actions combine components of the local innate immune system  and the intestinal epithelia in an interaction that preserves a tolerogenic functional steady state . A recent review by Roman and colleagues  has progThere are multiple mechanisms in the gut including a mucus layer, antimicrobial peptides and a tight junction protein network that cooperate to continuously preserve local homeostasis and hence ensure that the intestinal epithelial barrier integrity is maintained. Goblet cells secrete mucin to provide a protective coating, provide structural integrity and regulate macrophage and adaptive T cell responses during inflammation ,27,28,29Mental health is very much intricately linked to physical health . GastroiThe importance exhibited by the brain–intestine–brain axis is that it provides a bidirectional flow of neuroendocrine-immunological equilibrium control. The intestinal microbiome is thought to exert effects on this axis that significantly impacts the biochemistry of the central and peripheral nervous systems and in turn behavior   could be an important factor that disrupts the steady state of neuro-endocrine-immunological equilibrium in the intestinal mucosa, especially following the over prescription of antibiotics. We advance the idea that an in situ normal functioning vermiform appendix continually contributes to diversity and stability to the intestinal bacterial cohort over a lifetime. Probiotics that can regulate the functioning of the immune system in the gut may have important plausible implications in improving depressive mood states; dedicated studies are warranted.


Caenorhabditis elegans populations under partial selfing, exclusive selfing or predominant outcrossing, while they adapt to osmotically challenging conditions. We find that the ancestral genetic load, as measured by the risk of extinction upon inbreeding by selfing, is maintained as long as outcrossing is the main reproductive mode, but becomes reduced otherwise. Analysis of genome-wide single-nucleotide polymorphisms (SNPs) during experimental evolution and among the inbred lines that survived enforced inbreeding indicates that populations with predominant outcrossing or partial selfing maintained more genetic diversity than expected with neutrality or purifying selection. We discuss the conditions under which this could be explained by the presence of recessive deleterious alleles and/or overdominant loci. Taken together, our observations suggest that populations evolving under partial selfing can gain some of the benefits of eliminating unlinked deleterious recessive alleles and also the benefits of maintaining genetic diversity at partially dominant or overdominant loci that become associated due to variance of inbreeding levels.Partial selfing, whereby self- and cross- fertilization occur in populations at intermediate frequencies, is generally thought to be evolutionarily unstable. Yet, it is found in natural populations. This could be explained if populations with partial selfing are able to reduce genetic loads and the possibility for inbreeding depression while keeping genetic diversity that may be important for future adaptation. To address this hypothesis, we compare the experimental evolution of  Classic theoretical models posit a key role for deleterious recessive alleles in the evolution of reproductive mode modifiers , then prcf. Although classic models suggest the evolution of predominant selfing or predominant outcrossing should be common, comparative studies in plants and in animals have found that a number of natural populations show mixed selfing and outcrossing at intermediate frequencies . To explCaenorhabditis elegans has become a good experimental model to study how standing genetic variation for fitness depends on reproductive mode . For these reasons, and because sex segregates in a Mendelian fashion , and also the fertility of surviving inbred lines . The risAll populations in this study are ultimately derived from a hybrid population obtained by a funnel-crossing scheme where 16 parental wild isolates were reciprocally crossed two-by-two, and their hybrid offspring subsequently crossed also in a pairwise fashion, until obtaining the final hybrid population (ion (103 . During ion (103 .xol-1(tm3055)] into A6140, a mutant impairing X-chromosome dosage compensation and leading to the arrest of male development, to derive a monoecious population composed exclusively of hermaphrodites [homozygous for xol-1(tm3055)] that only reproduce by selfing (named M00). In parallel, we mass introgressed an autosomal sex determination recessive mutant allele [fog-2(q71)] into A6140, a mutant that eliminates self-spermatogenesis in hermaphrodites, to derive a trioecious population composed of males and females [homozygous for fog-2(q71)], and hermaphrodites [homozygous for fog-2(wt)] at an initial frequency of The genetic manipulation of sex ratios in A6140 has been detailed in The evolution experiment has also been previously reported in For line derivation, we followed standard protocols similar to mutation accumulation evolution experiments, where population sizes are kept to a minimum to allow fixation of segregating alleles in the population within each line in mostly a neutral fashion  populations so that we could derive inbred lines by selfing from all experimental populations and thus not confound potential selection under biparental and uniparental inbreeding as in Data from the inbred lines in low salt (25 mM NaCl), the environment where previous lab domestication and line derivation was done, was previously reported in Genomic DNA from A6140 and each of the G50 populations was extracted from individuals with the ZyGem prepGEM Insect kit and from pools of individuals from each inbred line using the Qiagen Blood and Tissue kit. A total of 830 SNPs distributed evenly across genetic distance, which was estimated by linear interpolation of the expected F2 map distances from All genotype data for the lines has been previously published in In ancestral and evolved experimental populations, SNP allele diversity was estimated as ozygotes . To avoinlme R package , with the following input formula for the nlme function:Linkage disequilibrium between pairs of SNPs was estimated as  i and j . Comparic, which is the genetic distance between SNPs, and x, which determines the rate of LD decay and can differ between populations . The underlying assumption is that the expected decay of linkage disequilibrium with genetic distance follows the equation given by N refers to the effective population size. Only SNPs segregating at frequencies between 0.05 and 0.95 were used.With this, we model the observed inbreedR . Likelihood ratio tests were employed for model selection. Zero-inflated negative binomial error distributions were chosen for subsequent analyses as they provided the best fit. We then employed generalized mixed effect models separately for 25 mM and 305 mM NaCl conditions, using the function glmmadmb from package glmmADMB (vs. evolved) and the reproductive system at generation 50, with assay blocks and replicate populations as random factors. Differences between experimental populations and the average of inbred lines derived from them was again carried out with the lsmeans and pairs functions in R  mutant allele in the heterozygous state, meaning they will also produce females through selfing, and male mating ability has had the opportunity to improve through sexual selection (As previously noted (P < 0.0001), a result that contrasts with values from androdioecious populations which, together with trioecious populations, only show a small decrease in allele diversity  did not result in a reduction of the ancestral genetic load. Trioecious populations maintained the ancestral risk of extinction . When coWe also attempted to detect genetic loads by comparing fertility between experimental populations and the inbred lines derived from them, given that a difference between the mean values of fitness components in populations and the mean value among the surviving inbred lines would indicate inbreeding (negative difference) or outbreeding (positive difference) depression . MoreoveGiven that inbred line derivation was done at low salt, the observed line extinction differences between reproduction systems might not be representative of fitness differences during experimental evolution. This problem does not appear to be of much concern because we detected a positive genetic correlation in fertility across the two salt environments for the androdioecious populations and no obvious trade-off between high and low salt in the other reproduction systems .SNP and haplotype diversity metrics were calculated among the lines that survived inbreeding by selfing in order to detect selection during inbreeding. In trioecious and androdioecious populations, simulations of genetic drift during inbreeding and sampling predict that SNP diversity among lines is maintained or slightly reduced whereas haplotype diversity is always expected to be reduced . HoweverFurther evidence for strong selection during the inbreeding assay comes from the SNP frequency changes observed during experimental evolution . For trioecious and androdioecious populations, there is a negative correlation in differentiation during experimental evolution and inbreeding, while in monoecious populations only a much weaker relationship could be found.C. elegans reproducing by selfing for 50 generations evolved reduced risk of extinction when maintained at very small sizes and under extreme inbreeding conditions. This result, which is consistent with the reduction of an ancestral genetic load, was likely caused by selection on viability loci given the similar reproductive outputs that were found in populations and among the surviving lines after inbreeding appear to rule out fertility as a major fitness component. Trioecious populations, which reproduced predominantly by outcrossing, had the same risk of extinction upon extreme inbreeding as the ancestral population, suggesting that they maintained the ancestral genetic load. We also found that populations that experienced some degree of outcrossing during experimental evolution (trioecious and androdioecious populations) maintained more genetic diversity than that expected solely under genetic drift, or under genetic drift and directional selection.In this study, we found that genetically diverse populations of i.e., variation in the degree of individual heterozygosity created by variation in past ancestry of selfing and outcrossing, could result in the maintenance of genetic diversity because of selective interference between completely recessive deleterious alleles, or because of the interaction between genetic drift and selection on beneficial alleles  associative overdominance generated by deleterious recessive alleles at high linkage disequilibrium and in repulsion phase or, (2) heterozygote advantage generated by overdominant loci . LinkageIf excess genetic diversity during experimental evolution resulted from overdominant loci and/or deleterious recessives in identity disequilibrium, then androdioecious populations should have maintained some of the ancestral genetic load .C. elegans, albeit always in strong linkage disequilibrium and at close physical distance, e.g., Under partial selfing (androdioecy), heterozygote advantage could be also generated by recessive lethals in repulsion phase, which are effectively overdominant loci despite the potentially large physical distances between them. Distinguishing these alternatives would require mapping the relevant fitness loci in the genome, an endeavor that is notoriously difficult and beyond the scope of the present study. Recessive sub-lethals in repulsion have been described in natural populations of Monoecious populations show an overall reduction in genetic diversity that is in line with neutral expectations under exclusive selfing . It is pPhysa acuta, specifically designed to disentangle sexual selection from selfing in the purging of deleterious recessives, has failed to find a significant role for sexual selection . We have previously shown that in the novel salt environment populations from all three reproduction systems had similar adaptive rates [Figure 4 in Selfing rates under androdioecy were unstable during experimental evolution and, unless male fitness components were to evolve, exclusive selfing would be achieved in less than 100 generations . It is t


Creativity has been defined as requiring both novelty and effectiveness, but little is known about how this standard definition applies in music. Here, we present results from a pilot study in which we combine behavioral testing in musical improvisation and structural neuroimaging to relate brain structure to performance in a creative musical improvisation task. Thirty-eight subjects completed a novel improvisation continuation task and underwent T1 MRI. Recorded performances were rated by expert jazz instructors for creativity. Voxel-based morphometric analyses on T1 data showed that creativity ratings were negatively associated with gray matter volume in the right inferior temporal gyrus and bilateral hippocampus. The duration of improvisation training, which was significantly correlated with creativity ratings, was negatively associated with gray matter volume in the rolandic operculum. Together, results show that musical improvisation ability and training are associated with gray matter volume in regions that are previously linked to learning and memory formation, perceptual categorization, and sensory integration. The present study takes a first step towards understanding the neuroanatomical basis of musical creativity by relating creative musical improvisation to individual differences in gray matter structure. The study of creativity and flow are central to positive psychology and neuroscience. We often know when we are experiencing creative works of art; yet it is impossible to find a single dimension along which to rank all works of creative genius. This is especially true of music. The standard definition of creativity in the psychological literature requires both novelty and effectiveness , have shown both spectral and temporal differences in brain activity among groups of subjects with varying levels of improvisation training  studies compared spontaneous improvisation against controlled performance on the keyboard, and revealed a network of activations and deactivations in medial prefrontal cortex (MPFC) and dorsolateral prefrontal cortex during jazz improvisation , especially during socially interactive improvisation . The prompts varied in either rhythm or pitch. Twelve different trials were presented from a computer. Each trial consisted of a listening phase (two measures), a continuation phase (eight measures), and an improvisation phase (eight measures). Visual cues were given on the screen throughout the listening phase (“Listen”), the continuation phase , and the improvisation phase (“Improvise”). In addition, a metronome was presented at 100 bpm to keep time throughout the entire trial.Subjects were instructed to listen to the clip two times during the listening phase, to play along with the prompt eight times during the continuation phase, and then to improvise in the most creative way they could be based on the prompt given, for another eight measures until the metronome stops. No additional instructions were given on how to improvise, nor were any guidelines given for what constitutes creativity. All subjects completed this task on a Casio PX 150 MIDI keyboard. Subjects who self-identified as playing other instruments additionally performed on their instrument of choice. MIDI data were collected through Max/MSP using the borax function, which recorded the pitch, velocity, duration, and inter-onset interval for each note received by the keyboard. All performances were also recorded using a Zoom Q8 video camera.3). We also acquired resting state fMRI and DTI images, which will be described in a separate report.T1 images were acquired from all participants in a 3T Siemens Skyra MRI scanner at the Olin Neuropsychiatry Research Center at the Institute of Living. Anatomical images were collected using a T1-weighted, 3D, magnetization-prepared, rapid-acquisition, gradient echo (MPRAGE) volume acquisition  and one experienced jazz improvising musician (Rater 2). Expert raters were asked to listen to each anonymized recording of each improvisation, and to rate the recording on a scale of 1–6 for creativity and imagination, with 1 being “Not creative and/or imaginative” to 6 being “Creative and/or imaginative.” Rater 1 completed the full dataset of 456 ratings . Rater 2 completed ratings for 10 subjects , but stopped after 120 ratings due to lack of interest. Rater 3 completed 432 ratings ; two subjects were tested after Rater 3 already completed the other ratings; thus the last two subjects were not rated by Rater 3. Each rater’s ratings were averaged across the 12 trials performed by each subject to obtain an average score given by each rater to each subject. We then obtained an averaged creativity rating for each subject by averaging across all available raters’ data for that subject.Example audio files of subjects’ production are available online at p < 0.05 FWE-corrected or FDR-corrected levels. We, therefore, applied a combined threshold with voxel-wise significance level of p < 0.001 (uncorrected) and a cluster-correction of k > 10 voxels, to capture results that surpass both a voxel-wise and an extent threshold. While the use of uncorrected voxel-wise significance level was relatively liberal, the additional application of the extent threshold served to reduce the likelihood of type 1 errors.VBM analysis  = 0.9, n.s.).Mean creativity rating across the three expert raters was 3.19 (SD = 0.96). Cronbach’s Alpha across the three raters was 0.932, confirming high inter-rater reliability. Cronbach’s alpha was calculated in SPSS using list-wise deletion to account for missing data resulting from incomplete datasets from raters. Since list-wise deletion does not take into account the subjects that only received two out of three possible ratings, we also separately show the pairwise correlation matrix between each pair of raters. The three raters’ average scores were all highly correlated, as shown in the inter-rater correlation matrix in R2 = 0.693, p = 0.003). Duration of improvisational training was the most significant predictor of creativity ratings , whereas duration of general musical training did not significantly predict creativity ratings . Performance on pitch discrimination , Digit span , and Shipley  baseline tests did not significantly predict creativity ratings.Multiple regression was used to test if training and performance on background tests predicted creativity. We ran a multiple linear regression analysis on the dependent variable of averaged expert ratings of creativity, with the independent variables of duration of improvisation training and duration of general musical training, as well as scores on pitch discrimination, digit span, and Shipley tests. This regression was significant, with the combined factors explaining 69% of the variance . These clusters were identified using the Automated Anatomical Labeling (AAL) atlas (Tzourio-Mazoyer et al., A whole-brain regression on gray matter volume with the covariate of averaged creativity ratings showed no significant voxels at the t and k thresholds, in the right rolandic operculum. Scatterplots again showed a negative relationship between the duration of improvisation training and gray matter signal: participants who had more improvisation training had lower gray matter signal in the rolandic operculum. A whole-brain regression on gray matter volume with the covariate of duration of improvisation training showed a single cluster that surpassed both In this study, we combine behavioral and voxel-based morphometry methods to relate brain structure to creativity in musical improvisation. Results show that expert ratings of creativity on an improvisation task are associated with differences in gray matter structure and that these associations are distinct from neuroanatomical correlates of training in musical improvisation.Our musical improvisation continuation task is modeled after previous studies and is designed to be doable by participants of all levels of training (Pinho et al., Individual differences in gray matter volume as identified in voxel-based morphometry may reflect variations in neuronal cell bodies themselves and/or from differences in relative density of cell bodies which gives rise to gyrification patterns, which may, in turn, facilitate connectivity towards those cell bodies (Ashburner and Friston, Creativity ratings were negatively associated with gray matter volume in the hippocampus. The hippocampus is primarily involved in learning and memory formation; recent work has linked this structure to creativity tasks as well. A recent voxel-based morphometry study found that hippocampal volume was correlated with performance on the remote associate’s test, a verbal creativity task (Tu et al., The inferior temporal gyrus is part of the “what” pathway in the visual system. Specifically, the cluster that we find to be associated with averaged creativity ratings falls in the gray-white matter boundary between the right posterior inferior temporal gyrus and the fusiform gyrus, in an area that is activated during studies that involve categorization of meaningful stimuli ranging from objects such as tools and chairs (Ishai et al., The rolandic operculum is anatomically between the parietal and temporal lobes and includes multisensory integration areas including secondary somatosensory cortex. Activity in the rolandic operculum has been reliably observed during interoception which is the awareness of one’s own bodily sensations, such as the awareness of one’s own heartbeat (Blefari et al., Surprisingly, our study found no significant associations with creativity ratings or duration of improvisation training in the prefrontal cortex nor in the frontal lobe. This stands in contrast to two VBM studies on creativity outside of music, which showed negative associations between creativity, in particular, artistic creativity, and gray matter volume in the anterior cingulate cortex and the SMA (Chen et al., Summarizing the VBM findings, gray matter volume in the bilateral hippocampus and the right inferior temporal gyrus, which are involved in learning, memory formation, and object categorization, together reflect differences in musical creativity as assessed by expert ratings on an improvisation task. Performance on the musical improvisation task shows different neuroanatomical correlates from the duration of musical improvisation training, which is negatively correlated with gray matter volume in the rolandic operculum, a region likely involved in sensory integration.p < 0.05 FWE or FDR-corrected levels. Second is that the musician participants in our study are relatively early in their musical careers; thus the relationship between creativity and gray matter may not necessarily extend towards more experienced players. Third, more than two-thirds of the participants in this sample are male; this is similar with other neuroimaging studies on musical improvisation (Limb and Braun, This study is first to relate musical improvisation behavior to gray matter correlates in brain structure; however, there are several limitations. First, the sample size is relatively small for a VBM study. This could contribute to the major caveat: that our results do not survive correction for multiple comparisons at the Taken together, we present first results relating individual differences in brain structure to expert ratings of performance in a musical improvisation task. The results show that individual differences in musical creativity, as assessed by an improvisation task, are associated with regions implicated in memory formation and categorical representation, whereas regions implicated in sensory integration are associated with duration of improvisation training. The use of VBM enables the identification of specific regions in the brain that has demonstrated functions, and knowledge of these functions then shed light on how the brain accomplishes the complex creative task of musical improvisation. Future work will expand the current approach to a larger sample size, and also apply other data-driven measures to predict creativity and relate them to brain structure and function. By relating brain structure to the perceived creativity of musical output, the present preliminary results set the stage for further research towards the neural correlates of musical creativity.This study was carried out in accordance with the recommendations of “IRBs of Wesleyan University and Hartford Hospital” with written informed consent from all subjects. All subjects gave written informed consent in accordance with the Declaration of Helsinki. The protocol was approved by Wesleyan University and the Hartford Hospital.PL conceptualized the idea behind this manuscript, performed data analyses, and wrote the first draft. CA, EP and TZ acquired and preprocessed the behavioral and neuroimaging data. CA and CP analyzed the behavioral and neuroimaging data. All authors revised the manuscript and approved the submission.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


The aim of the study was to identify the mechanisms relating to parental control, adolescent secrecy, and school context that shape patterns of adolescent drinking frequency and appraise the implications for systems-level intervention.The Belfast Youth Development Study collected information on friendship networks in schools, alcohol use, and Stattin and Kerr's parental monitoring subscales across 5 years of postprimary school education in annual waves from age 11–15 years. Stochastic Actor-Oriented Models were fitted to 22 schools  to assess friendship formation and peer influence processes related to drinking frequency and their variation by parental control or child secrecy. Meta-regressions and summary statistic ego-alter selection tables assessed how network and behavior co-evolution varied according to school gender and the proportion of weekly or more frequent drinkers in each school.Adolescents tended to mimic their peers' drinking levels, and frequent drinkers befriended those who drank similarly to them. Those with high parental control were less likely to befriend low-control peers, whereas low-control pupils were more likely to befriend each other. Adolescents with low-control parents nominated fewer friends in schools with higher proportions of drinking frequently. There was a tendency toward befriending highly secretive peers in boys schools only.Our results suggest that the optimal strategy for selecting seed nodes in a diffusion of innovations network intervention may vary according to school context, and that targeting family interventions around parent characteristics may modify the wider school network, potentially augmenting network intervention processes. Network analysis explained how peer and family social processes interact to influence adolescent alcohol use patterns and how these vary by school context. These findings suggest implementation strategies for “diffusion of innovation” interventions could differ according to school context, and targeted family intervention components may enhance school network interventions.Public health interventions that are based on a thorough understanding of the complex social system in which they operate are those most likely to be effective and lead to sustainable change. An appropriate approach to develop systems-level understanding is to take a broad conceptualization of theory, drawing on ideas from different disciplines, to describe the system in question In this article, we use modeling to conceptualize the social system relating to adolescent drinking frequency and discuss the implications for interventions in the school and family context.While acknowledging that other theories  could be applied, we have used theories that focus specifically on adolescents and peers and adolescents and family. Erikson's theory of identity development suggests adolescents' self-concept develops according to how others view them at the expense of self-reflection, engendering conformity and mimicry RQ A: Is similar drinking frequency selected for in friendship?RQ B: Do adolescents modify their alcohol use to mimic their friends?RQ C: Is secrecy socially transmitted?Previous studies of adolescent drinking using Stochastic Actor-Oriented Models (SAOMs) found evidence for both selection and influence processes; but studies varied in uncovering one, the other, or both processes. There was further variation in whether the processes appeared in early versus late adolescence. The patterns may be due to the use of different alcohol variables: an SAOM for first use of alcohol RQ D: Does parental control influence friendship formation?RQ E: Does parental control influence the tendency to befriend drinkers?RQ F: Does parental control mitigate peer influence on alcohol behavior?Koepke's integrated theory considers the dynamic relations between child identity and parent–child relationship within a family system. From this perspective, parents mediate the relationship between child and society, affording greater social exploration may lead to the social environment having more of an influence on behavioral aspects of self heteronomyautonomyRQ G: Does friends' alcohol use induce secrecy?RQ H: Are secretive pupils more prone to influence?RQ I: Is secret keeping selected for in friendship?We operationalize adolescent agency via secrecy to study how individual choices shape the social environment. Adolescent secret-keeping can be seen as two pronged, having positive aspects through creating an independent identity and strengthening social ties to peers, but carrying an increased risk of psychological strain through insufficient parental support, engendering peer RQ J: Does school gender influence selection and influence processes (SIP)?RQ K: Does the proportion of frequent drinkers in the school influence selection and influence processes?Contextual features of schools could influence how social processes unfold and thus affect the context dependence of a social intervention The aim of the article was to identify theory-informed mechanisms acting across multiple levels of the social system  that influence adolescent drinking frequency. In support of this aim, we will answer research questions A to K above and discuss the findings in relation to the design of health interventions.The Belfast Youth Development Study (BYDS) is a school-based study of drug and alcohol use. All the post primary schools in Belfast and two intermediate townlands in Northern Ireland were invited to take part, 71% agreed. All students in participating schools were surveyed in their first year of post primary education in the academic year 2000/2001 and annually thereafter for 5 years of compulsory schooling. The study is described in detail elsewhere In each year of the survey, participants were asked to name their best friend and up to nine other friends in their school year. Social network information was collected from 42 schools. Our analysis used schools with <20% missing data on friendship nominations.We included each pupil's gender and free school meal eligibility as main effect predictors of behavior and dyadic covariates to model the tendency for friendship ties to form between similar peers.The alcohol frequency measure was based on questions relating to ever used alcohol (yes/no) and frequency of drinking asked in each year of the study. The four-category variable was never, infrequently , monthly, and weekly or more frequently. The parental control subscale and child secrecy items within the child disclosure subscale of the Stattin and Kerr parental monitoring scales were used in analysis  and overall drinking prevalence  were entered as predictors of variation in parameters in a meta-regression. School results were combined with empirical Bayes random effects meta-analysis using the R Package metafor. Where analyses suggested there were variations in selection processes, we produced summary ego-alter selection tables by school type. This allowed us to scrutinize the between-school variation in asymmetries in friendship formation and “opportunity hoarding” patterns that would be difficult to see by looking across separate model results.All structural, covariate, and hypothetical parameters were entered into a full model, and these models were updated using previous results to improve convergence. In one school, we fixed one parameter at zero to enable convergence; otherwise, we retained nonsignificant parameters to conduct meta-analyses and time trend tests. We assessed time heterogeneity in our research question parameters. There was some evidence that the influence of alcohol, parental control, and secrecy on friendship ties may vary across the study years, but not for influence processes. This contrasts with those of previous studies stats.ox.ac.uk/∼snijders/siena.We fitted unconditional methods of moments estimation for SAOMs using the R Package RSiena There were nine coeducational schools, eight girls schools, and five boys schools in the final analysis with a total of 3,220 pupils in the sample. The network structural parameters were broadly comparable across all schools, with expected tendencies for gender assortativity, reciprocal friendship, popularity effects, and evidence of a similarity preference according to free school meal eligibility .There was some evidence that selection by secrecy was stronger in single gender compared with coeducational schools (J); high parental control reduced outgoing friendship ties in schools with higher proportions of frequent drinkers (K); and, that adolescent drinking was more strongly associated with a reduction in parental control in schools with a higher proportion of drinkers (K).The coefficients in the ego-alter selection tables , Table 5Parental control's influence on friendship formation shows a different pattern . Pupils Considering all schools combined, tie formation does not appear strongly patterned by adolescent secrecy, but the meta-regression identified school variation in tie formation by secrecy. Stratified by school gender , secrecyThis article used complex systems methods to scrutinize how school, peer, and family environments relate to adolescent drinking, making two novel contributions. First, we have uncovered elements of family and school context influencing the formation of friendship groups and drinking patterns; second, we have demonstrated how SAOMs, meta-regression, and meta-analysis of ego-alter selection tables help understand opportunity hoarding and the formation of inequalities between groups in social network data, which has implications for how to implement network interventions.Individual agency (peer selection) and social structure (peer influence) both play a role to explain the clustering of drinking behavior within schools, although friend selection is driven by prodrinking rather than nondrinking peers. Intergenerational closure–befriending peers with similar parents If we aim to intervene, then alcohol use is better studied as a socially situated practice rather than a health risk outcome First, the school context may change the reach of peer-led school interventions, although the change processes may be the same. Drinking mimicry did not vary according to our theoretical expectations around normative differences related to school gender or school-level drinking, suggesting diffusion of innovation interventions Secondly, addressing low-control parenting practices may interrupt the formation of high-risk school cliques, whereas raising moderate or high levels of parental control will have little spillover effect on other peers. This suggests that a “universal school”  but “targeted/proportionate community” (focus on families with higher risk profile) intervention could be more effective and resource efficient Our meta-analysis of ego-alter selection tables allows us a better understanding of the processes around social closure than is possible by looking at summary statistics for tie formation parameters. Theories relating to community and social control would suggest that a friend's parents could influence one's own behavior in adolescence empirical—simply assessing patterns of change in the survey data—and instead to use simulation of real processes  that generate observed change in our data, but we have insufficient information to explore actual mechanisms of change and explanation for change by school context The five waves of network data in the Belfast Youth Development Study gave the opportunity to study social influence from the move into postprimary school throughout the transition into adolescence, the time when social ties to peers becomes most salient for determining behavior. The large number of schools allowed us to study both generalizable processes as well as variation with school and family context. SAOMs also provide advantages in dealing with nonindependent observations, and the ability to study selection, influence, and contextual processes. Our study also has limitations. Our parental monitoring measures were adolescent rather than parent reported and thus could be biased according to attitudinal, social, or demographic variation or other individual differences. Second, we are unable to explore our postulated theoretical processes in depth using quantitative data alone. SAOM provides a method to move beyond Bhaskar's Although there is no evidence that parenting practice changes peer processes directly


Phlegmasia Cerulea Dolens (PCD), a rare & life-threatening condition caused by a massive deep venous thrombosis that is associated with arterial occlusion caused by the subsequent compartment syndrome.A 56-year-old male was diagnosed as a case of extensive left femoral DVT & pulmonary embolism. Two days after being managed by systemic thrombolytics & heparin, his condition worsened as he developed cyanosis of the affected limb, compartment syndrome & foot drop so he was referred to our facility for further management. CT venogram showed a thrombosis of the left popliteal vein extending into the left common iliac vein confirming the diagnosis of PCD & May-Turner syndrome. We adopted a limb preserving approach using a pharmacomechanical catheter directed thrombolysis (PCDT). The patient recovered fully with a complete resolution of his foot drop.Several treatment options have been suggested to improve the outcomes of PCD, but due to the rarity of this condition a gold standard treatment is still controversial. But regardless of the chosen approach, there is an urgent need to decrease the thrombus burden to prevent further adverse sequelae like amputation or even death which can be achieved by using PCDT as it was demonstrated in our case.Our case shows that a rare entity of DVT as PCD could be a result of improper management of acute proximal DVT in the background of anatomical variabilities & that despite the late presentation of such a rare condition there still a role for a limb preserving approach with endovascular techniques. Phlegmasia Dolens is sub classified into: 1-Phlegmasia Alba Dolens (PAD) which is a milder, non-ischemic  form of PD where there is a subtotal occlusion of the affected vein and intact collateral venous system 2-Phlegmasia Cerulea Dolens (PCD) which is the worst clinical scenario of venous thrombosis that a patient can present with aside from a massive pulmonary embolism . PCD is 2We report a case of a 56-year-old male medically free with a history of long travel two days prior to his presentation to another hospital complaining of: left leg swelling, pain & shortness of breath of 2 days duration where he was diagnosed as a case of extensive deep left femoral vein thrombosis & pulmonary embolism. He was kept on systemic thrombolytic therapy & heparin. Two days later, the patient condition started to deteriorate so he was referred to our facility for further management. When he presented to our facility he was in respiratory & pain distress, but hemodynamically stable. Left Lower limb examination showed : cyanosiSo, fasciotomy was done then he was shifted to the angio suite for pharmaco-mechanical thrombolysis. Under ultrasound guidance & putting the patient in a prone position, the occluding thrombus was accessed distally from popliteal vein & a retrograde venogram was done, which showed a thrombus that almost completely occluding the popliteal vein  extendinThen the wound was closed by delayed primary closure. The patient condition continued to improve, the arterial system became intact , and he was discharged with anticoagulant (NOAC) and follow-up with physiotherapy to manage his partial foot drop, which was resolved completely later on. A coagulation profile has been done for our patient which turned to be negative. Hence, the cause of our patient condition is most likely 2ry to the prolonged travailing with the coexisting May---Turner syndrome.3Several treatment options have been suggested to improve the outcomes of PCD, but due to the rarity of this condition a gold standard treatment is still controversial. Yet the general initial management should include absolute bed rest, affected leg elevation, fluid resuscitation, and the intravenous heparin. Anticoagulation alone has no role in removing the existing thrombus, as the anticoagulant role is to prevent the progression of the thrombus & the formation of a new one ,6. The n4Phlegmasia Cerulea Dolens is the worst form of deep vein thrombosis. It could develop after an acute proximal DVT & carries a significant risk of mortality & morbidity. An early detection and appropriate decision regarding the line of management is crucial to save the patient and to preserve the limb and its function.The authors have no conflicts of interest.None.Case reports are exempted from ethical approval according to policies of Imam Abdulrahman Bin Faisal University.Written informed consent was obtained from the patient for publication of this case reportAyman ELsaid: writing the paper, reviewing final manuscriptAbdullah Saleh AlQattan: writing the paper, reviewing final manuscriptEhab Elashaal : writing the paper, reviewing final manuscriptHumood AlSadery: literature review & writing the paperIbrahim AlGhanmi : writing the paperBander Fuhaid Aldhafery : writing the paper, reviewing final manuscriptDoesn't apply.Ayman ELsaidAbdullah Saleh AlQattanNot commissioned, externally peer-reviewed.


Investigations of police performance during acutely stressful situations have primarily focused on higher-order cognitive processes like attention, affect or emotion and decision-making, and the behavioral outcomes of these processes, such as errors in lethal force. However, behavioral outcomes in policing must be understood as a combination of both higher-order processes and the physical execution of motor skills. What is missing from extant police literature is an understanding of how physiological responses to acute stress contribute to observed decrements in skilled motor performance at the neuromuscular level. The purpose of the current paper is to fill this knowledge gap in the following ways: (1) review scientific evidence for the physiological  responses to acutely stressful exposures and their influence on skilled motor performance in both human and animal models, (2) review applied evidence on occupationally relevant stress physiology and observed motor decrements in performance among police, and (3) discuss the implications of stress physiology for police training and identify future directions for applied researchers. Evidence is compelling that skill decay is inevitable under high levels of acute stress; however, robust evidence-informed training practices can help mitigate this decay and contribute to officer safety. High level motor performance skills, including the use of physical control techniques and weapons, are expected of law enforcement officers who routinely operate under acutely stressful work conditions. Mistakes in the application of physical skills can have devastating effects on the individuals involved in such incidents, with serious implications for long-term physical and mental health. Yet, much of the applied research on police performance under stress does not speak to the effects of acute stress physiology on the physical  aspects of skilled motor performance, which is necessary to optimize training and best practices. The goal of this paper is to synthesize information from peer-reviewed indexed journal articles in the basic and applied sciences, which address the impact of stress physiology on skilled motor performance among police as a novel contribution to the literature. Following a brief discussion on the definition of “stress,” this paper reviews various physiological responses to stress. Using both animal and human evidence, we outline the impact of stress physiology on motor unit recruitment and the skilled performance of motoric workplace tasks. Converging lines of evidence provide a theoretical framework for understanding stress-induced decrements in skilled occupational performance, including a limited body of applied research on stress physiology among police. We conclude with a review of the efficacy for scenario-based training in improving performance decrements among police by way of adaptively inducing skill-appropriate stress and provide future directions for applied research.The term “stress,” as originally introduced by Independent of the type of stressor, a physiological stress response is initiated by the brain and can be understood as a nonselective response  that acts to reorient the individual’s cognitive and physiologic capacities to deal with the challenge and return to the original state of homeostasis . SituatiThe physiological response to a stressor occurs largely outside conscious awareness, arising from neural circuits that are also responsible for imbuing meaning and personal relevance to external stimuli . In respAdaptive SNS arousal is beneficial for performing optimally during critical incidents. The benefits of adaptive arousal include alertness, focused attention, and improved cognitive performance . During via the activation of the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis prompts the release of hormones, including corticotropin releasing factor (CRF) from the hypothalamus  and the low-affinity glucocorticoid receptor GR; . Once boIt has long been hypothesized that increased muscle tension occurs during stressful situations , althougWhile Even popular culture recognizes the impact of acute stress on motor performance; as illustrated by a classic movie situation in which someone is stalked by an aggressor, gross motor behavior like running away is not problematic. But once at the door, they frantically try to unlock it and experience difficulty inserting the key into the lock. This example best exemplifies the considerable impact of stress on motor skills that require finer control over developed muscle tension, and muscle fiber firing patterns that allow for smooth and accurate movement.As opposed to skilled movements requiring finer motor control, general motor patterns, such as navigating through a novel environment, are determined mainly by cognitive, emotional, and motivational aspects, and therefore they do not offer a useful model for studying the mechanisms of how stress interacts with the motor system. Skilled movements, however, are an ideal model to examine discrete motor disturbances in response to stress and stress-induced neuroplasticity. Studies in rats have shown that, through direct interaction of CORT and GRs as well as emotional changes, stress can alter the movement trajectories and accuracy of skilled movements in forelimbs and hindlimbs, and disrupt inter-limb coordination . FurtherA variety of studies have described the contribution of distinct motor areas to skilled reaching movements in humans and animals, mainly through the study of focal lesions of the underlying neural substrate. These investigations revealed discrete changes in the qualitative movement trajectories of reaching for food produced by areas such as the red nucleus , corticoThe physiological mechanisms that predict skilled motor performance decay under high stress primarily involve the brain’s ability to initiate the proper motor sequences and less to do with changes at the contractile sites within muscle tissue. In support, there are three lines of evidence rooted in fundamental scientific research in animal and human models that suggest that stress and GCs are likely to affect central motor control.Brain regions participating in motor control have receptors for GCs. Brain regions participating in motor control, such as motor cortex, cerebellum, basal ganglia, and spinal cord, have a significant density of GRs  and fine movements  in experienced police officers, self-reported anxiety increased and shooting accuracy was reduced, even if the preferred movement strategy puts the officer at greater risk .While the influences of acute stress on police performance have largely focused on cognitive functions, such as decision-making, learning, and memory see , a compaIndividuals employed in public safety and protection environments are often exposed to a wide variety of stressors, and the response to each type of stressor will vary greatly across the population or different responders. As one would expect, various physiological measurements have revealed increased stress reactivity during physical and psycho-social aspects of police work in active duty settings ,c. AnderMore recently, work by A misconception remains among some police trainers and law enforcement agencies that simulation training cannot elicit real world stress responses because the results of the training are not grievous. A growing body of research shows that this is not the case and demonstrates significant increases in police officers’ stress physiology during high threat simulations or scenarios relative to rest . Using sPhysiological responses to stressful encounters observed in police officers and described above are typically paired with decrements in skilled motor performance. The investigations by Nieuwenhuys, Oudejans, and colleagues summarized above demonstrate significantly greater physiological arousal as well as shooting skill deterioration under high stress conditions that included a heavily armed person or cannon that could shoot back at the officer, versus low threat conditions with static or unarmed targets. Stress-induced decrements to participants’ shooting performance include decreased accuracy, faster reaction times, and more false positives  , 2015. Tbefore drawing their firearms were faster at reaching a safe zone, and that officer’s finger-indexing  and tactical positions  significantly impacted performance time. Therefore, training that promotes skill learning by inducing stress can help override natural, unconditioned startle responses or preferred positioning that could endanger officers during critical incidents.As another variant of gross (versus fine) motor skills, complex motor skills typically used in the line of duty, including non-verbal communication, arrest, and self-defense skills, have also been shown to degrade under high versus low stress conditions . Arble eThese investigations provide evidence for decrements in the cognitive  and visuomotor processes  underlying motor performance under stressful simulated environments. However, the precise mechanisms by which occupationally relevant stress physiology impairs neuromuscular aspects of skilled motor performance among law enforcement remain unknown. Inferences from fundamental scientific literature using animal and human models described above can be drawn, but future investigations accounting for the unique and highly dynamic nature of police work can begin to fill this gap in the applied literature while also contributing to the development of evidence-based training practices.cf, Prior to skill mastery, novice learners need to learn fundamental motor skills in the absence of high stress conditions. Component “chunks” of behavior should be learned in a progressive manner, with increasing skill complexity once movement patterns are engrained, efficient, and accurate. Once primary skills can be demonstrated at a high level of performance, training should progress to the application of these skills in a wider variety of complex situations that also increase the stress response cf, . While tA growing body of research reveals the effectiveness of live simulation or scenario-based training for improving stress-induced decrements to skilled motor performance among first responders. Scenario-based training is founded on adult learning principles that adaptively expose officers to realistic and occupationally relevant stressors in a safe, controlled environment. With constructive feedback from experienced trainers, correct motor strategies are encoded either through correct performance or feedback on errors that can be made without life-threatening consequences. Scenario-based training is effective for teaching both new skills or refreshing essential skills that can be recalled and utilized more successfully under the same stressful conditions with which they were taught .Physiological stress responses are induced during scenario-based training by using realistic actors, environments, props, and subject matter that are challenging for the skill level and experience of the student . ScenariIn the previously reported investigations that show stress-induced decrements to skilled police performance, officers that trained with live opponents under high threat, stress-inducing conditions performed better than officers trained using static targets under low threat conditions . AnderseThe use of video simulation technologies for police use of force training is increasing in popularity . The staWhile animal models would suggest skilled motor performance decrements are inevitable under high stress, applied police research has shown significant improvements in various aspects of skilled motor performance following training under highly stressful conditions. Nonetheless, the direct influence of occupationally relevant stress physiology on neuromuscular aspects of skilled motor performance among law enforcement remains less clear. Before such investigations can occur, it is important that researchers carefully evaluate and define “performance” on more dimensions than just the behavioral outcome , which can be interpreted as reflecting cognitive decision-making processes as much as physical performance capability, quality, or success see . Haller via electroencephalography (EEG) and electromyography (EMG), respectively. The frequency (time series) and amplitude of neuromuscular signals under high- and low-stress conditions could be compared to identify the influence of stress on the speed and timing of motor skills, including reaching for and utilizing a firearm. Muscle tension as recorded by EMG could also reveal subtle differences between anticipatory  and physical stress, clarifying whether these stressors manifest similarly in musculoskeletal architecture.Once skilled motor performance has been operationalized, various non-invasive methodological approaches can be used to pinpoint the contribution of stress physiology on musculoskeletal functioning. Electrical brain signals originating in motor cortex and terminating in targeted muscle groups can be measured using surface-level electrodes Training aimed at reducing police performance errors in the use of lethal force have already started to focus on physiological-based interventions, including physiological stress modulation . In an eA growing body of literature has demonstrated significant physiological activation following exposure to acutely stressful events among police, both in real-world and simulated settings. However, there are little data that document the direct impact of stress physiology on skilled motor performance at the central  or peripheral (neuromuscular) level. Future investigations in this regard can aid in further optimizing effective interventions that train adaptive physiological stress responses to acutely stressful situations and which reduce errors in lethal use of force and improve physiological recovery from stress. Together, this evidence-based line of research can immediately improve stress-induced decrements to skilled motor performance, preserve occupational and public safety, and reduce the risk for physical and mental health disorders disproportionately observed in first responder populations .GA and GM completed the first conceptualization and draft of the manuscript. JA conceptualized components and wrote sections of the manuscript. PD contributed to writing significant revisions of the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


In recent years, the altitude acclimatization responses elicited by short-term intermittent exposure to hypoxia have been subject to renewed attention. The main goal of short-term intermittent hypobaric hypoxia exposure programs was originally to improve the aerobic capacity of athletes or to accelerate the altitude acclimatization response in alpinists, since such programs induce an increase in erythrocyte mass. Several model programs of intermittent exposure to hypoxia have presented efficiency with respect to this goal, without any of the inconveniences or negative consequences associated with permanent stays at moderate or high altitudes. Artificial intermittent exposure to normobaric hypoxia systems have seen a rapid rise in popularity among recreational and professional athletes, not only due to their unbeatable cost/efficiency ratio, but also because they help prevent common inconveniences associated with high-altitude stays such as social isolation, nutritional limitations, and other minor health and comfort-related annoyances. Today, intermittent exposure to hypobaric hypoxia is known to elicit other physiological response types in several organs and body systems. These responses range from alterations in the ventilatory pattern to modulation of the mitochondrial function. The central role played by hypoxia-inducible factor (HIF) in activating a signaling molecular cascade after hypoxia exposure is well known. Among these targets, several growth factors that upregulate the capillary bed by inducing angiogenesis and promoting oxidative metabolism merit special attention. Applying intermittent hypobaric hypoxia to promote the action of some molecules, such as angiogenic factors, could improve repair and recovery in many tissue types. This article uses a comprehensive approach to examine data obtained in recent years. We consider evidence collected from different tissues, including myocardial capillarization, skeletal muscle fiber types and fiber size changes induced by intermittent hypoxia exposure, and discuss the evidence that points to beneficial interventions in applied fields such as sport science. Short-term intermittent hypoxia may not only be useful for healthy people, but could also be considered a promising tool to be applied, with due caution, to some pathophysiological states. The term “intermittent hypoxia” is widely used and applies to a wide spectrum of situations that range from alpine expeditions to obstructive sleep apnea (OSA). However, in physiological terms, there are often few similarities between these conditions  and in some sporting activities such as parachuting and extreme skiing, in which the subject may not even notice the hypoxia.Intervallic intermittent hypoxia, which is characterized by long periods of normoxia interspersed with periods of hypoxia, as seen in frequent alpine expeditions and trekking at altitude, mountain rescue teams, regular intercontinental commercial flight crews , and even astronauts at the International Space Station or future extraplanetary missions.Chronic intermittent hypoxia, which affects individuals who work under shift systems characterized by work at moderate or high altitudes alternating with periods of rest at sea level. This last model is common in the Andes region and in the Central Asian mining industry, but is also found in contractors for astronomical observatories, the military and customs, and police and border control personnel in many high-elevation countries.The concept of “hypoxic training” was coined during the 1930s in the academic environment of the former Soviet Union, and was considered a useful therapeutic tool after it was shown to have beneficial effects on a number of different pathologies, even though the mechanisms involved in these favorable effects were unclear  in hypobaric (low barometric pressure) chambers. A detailed study of the precise mechanisms that underlie these adaptive responses  in humans and in an experimental rodent model encouraged us to explore the possibilities of applying IEHH programs with biomedical and therapeutic purposes  is low, but increases when combined with exercise, with additional specific responses that are not observed when similar exercise levels are carried out in normoxia  and the Istituto Pio XII, Misurina, Auronzo at 1,756 m  devoted to childhood bronchial asthma. The first medical reference we found about bronchial asthma and altitude is an inquiry between the doctors of Davos referring that 133 among their 143 patients with bronchial asthma that spent their holidays in this mountain town, did not present any acute episode of asthma and that 81% reported persistent improvement of the illness  a different breathing control pattern  was first used by members of early Mount Everest expeditions to denote the deterioration in mental and physical condition due to prolonged time spent at high altitudes Ward, . It is win situ in the subventricular zone and dentate gyrus of rat brains , and the kind of hypoxia (hypobaric or normobaric), as is discussed below. The living high-training low (LH-TL) pattern  and normobaric  hypoxia. It seems evident that the same physiological effects are expected for a determined alveolar oxygen partial pressure, regardless of the technical means used. However, data in the literature present consistent discrepancies after applying hypobaric and normobaric hypoxia, which could be attributed to alterations in other environmental parameters that affect alveolar gas composition, such as carbon dioxide partial pressure, humidity and temperature. For instance, even for the same level of oxygen partial pressure, the atmospheric composition in a small hypoxic tent with low air turnover (limited by the flow capacity of the hypoxic device) can be very different from the air composition in a hypobaric chamber. Generally, the use of powerful vacuum pumps in hypobaric chamber systems guarantees sufficient renewal of the air inside the room, thus preventing carbon dioxide accumulation and a rise in air temperature and humidity, factors that could become unbalanced in small volume hypoxic tents, especially with exercising subjects inside. In a comparative study of hypobaric (low pressure chamber) and normobaric hypoxia (hypoxic tent) during a submaximal exercise test in the same subjects, differences were observed in some cardiorespiratory and heart rate variability parameters between the two artificial hypoxia systems used (Basualto-Alarcón et al., An interesting and dynamic debate, which is beyond the scope of this review, is currently under way among altitude researchers concerning whether or not hypobaric hypoxia induces different responses from normobaric hypoxia Girard, . Some evA growing body of knowledge supports the beneficial effects of natural or simulated altitude techniques on health outcomes (Navarrete-Opazo and Mitchell, GV, JV, AR, and LC contributed to the initial draft of the manuscript; GV and JT edited the document after contributions from all authors; All authors reviewed and approved the final version.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


This study aimed to assess on-the-ground barriers to the provision of oxygen therapy for paediatric patients in three government-funded Eastern Ugandan district general hospitals (DGHs).n = 29). MAXQDA qualitative data software was used to assist with response analysis.Site visits to DGHs during March 2017 involved semi-structured interviews with medical officers, clinical officers, paediatric nurses and non-clinical staff (The healthcare professionals reported that erratic electricity supplies, few and/or malfunctioning oxygen cylinders and concentrators, limited or no access to pulse oximetry, inadequate staffing and lack of continued professional training were key barriers to the delivery of oxygen therapy. Local populations were reportedly fearful of oxygen therapy and reluctant to consent for oxygen therapy to be administered to their children.According to healthcare providers in three Eastern Ugandan DGHs, numerous barriers exist to oxygen therapy for paediatric patients. Healthcare professionals reported lack of facilities and training to effectively deliver oxygen therapy. Quality improvement work prioritising oxygen therapy in government-funded district general hospitals should focus on oxygen supply and delivery issues on a site-specific level and sensitizing communities to the potential benefits of oxygen. Alongside general protection, prevention and treatment strategies, including feeding, vaccination and reducing household air pollution, for those who develop severe pneumonia oxygen therapy has been identified as a key area for development in the integrated Global Action Plan for Pneumonia and Diarrhoea (GAPPD) . This reFactors contributing to successful oxygen therapy are summarised in the ‘Oxygen Supply and Delivery Chain’ Fig. . A studyThe east African country of Uganda has a population of 38 million people and is one of the youngest and fastest growing in the world ” Nursing Officer, Atutur“maybe last time they put my brother on oxygen and he passed on so they kind of have such feelings” Nursing Officer, Atutur“sometimes you ask the mother and the mother may refuse and you cannot go forward to give the baby oxygen because the mother has refused” Nursing Officer, PallisaHealthcare professionals frequently reported fear of oxygen expressed by parents and carers of children:All healthcare professionals outlined what they believed should be done to facilitate improvement of oxygen therapy for paediatric patients in their hospital Fig. . These iThis study has identified numerous issues relating to oxygen therapy for paediatric patients from the perceptions of healthcare professionals involved in its’ supply and delivery. Across all sites, main barriers highlighted included poor electricity supplies, frequent concentrator malfunctions, low staffing levels and lack of training. At Atutur and Bududa DGHs, these barriers appeared compounded by lack of oxygen cylinders, lack of oxygen concentrators, lack of delivery equipment and no access to pulse oximetry, issues which were reflected in improvement proposals. Parents and carers’ fear of oxygen therapy provided an additional barrier to oxygen delivery to children. Through the prioritisation of oxygen supplies by administrative staff, effective communication between the stores and wards, large back-up supplies of oxygen cylinders with functional flow-meters, a paediatric-specific oxygen concentrator, access to and use of pulse oximetry, healthcare professionals at Pallisa DGH reported use of oxygen therapy that more closely adhered to international recommendations .The oxygen supply and delivery problems highlighted by our study reflect many issues raised in existing literature , 4, 6, 7Oxygen concentrators are frequently advocated as oxygen sources throughout the developing world –18, for The reliance on a stable power supply also presented a large problem for concentrators in all hospitals. A study by Peel and colleagues demonstrated lower voltages and frequent power outages caused electrical faults in concentrators and break down, possibly explaining the problems reported at each hospital in our study . Power sThe role of the nurses was comprehensive with regards to oxygen therapy, corresponding with the contents of the ‘Ugandan National Council for Higher Education Minimum Standards for Courses of Study for the Bachelor of Nursing Science’ . HoweverPatient/parent perceptions of oxygen in this setting are rarely reported on. Our study has highlighted the fear of oxygen amongst parents of paediatric patients and reflects a study by Stevenson and colleagues , who alsConsidering the reliance on signs and symptoms at Atutur and Bududa DGHs to establish hypoxaemia, it is concerning that signs and symptoms have been identified as poor hypoxaemia predictors. A study by Rao and colleagues demonstrated that, although poor, chest wall in-drawing, crepitation’s and nasal flaring were the three most sensitive predictors of hypoxaemia and cyanosis and nasal flaring had the best positive predictive value . This paConsidering the variation in reliability of symptoms used to detect hypoxaemia, emphasis must be placed on routine oximetry use.There were a number of limitations to this study. The selected sites were all government-funded district general hospitals in eastern Uganda and therefore external validity of results outside of this setting is questionable.No formal cost analysis or detailed auditing process of oxygen supply and delivery systems was conducted due to difficulty accessing comprehensive hospital records containing this information.No comprehensive assessment of power supply was undertaken in this study. However, triangulated insight from local healthcare professionals indicated that they could not rely on their current power supply. This highlights a specific area for quality improvement.The authors’ involvement with oxygen systems in similar settings to the study prior to carrying out this study may have biased data collection and the interview approach. However, data collection adhered closely to qualitative data acquisition techniques, ensuring reliability and validity . The DelThere are greater numbers of coded passages from Pallisa DGH compared to Bududa and Atutur DGHs, biasing responses towards Pallisa DGH. The semi-structured interview design meant some aspects of the supply and delivery chain were not discussed with all interviewees, which may have been mitigated using a structured interview framework. However, this inductive approach allowed response freedom from participants, allowing them to focus on aspects important to them and therefore gave a truer reflection of local issues. These include teamwork, communication, parents’ oxygen fears and patient transfers to other facilities not previously highlighted by other large studies , 4, 6, 7The coding process in transcript analysis should ideally be undertaken by multiple coders to incorporate multiple opinions . This stFuture studies assessing oxygen therapy should strive to understand local problems by interviewing providers of oxygen therapy. In addition, they should undertake a comprehensive site-specific cost analyses of running cylinders and concentrators over specific time periods coupled with reliability tests. This should be alongside assessment of back-up generators, fuel and cylinder transport costs. This will deduce the most suitable oxygen supply for a specific site, which may include cylinders, concentrators, a combination of the two or a local oxygen plant. Linking improvements in oxygen supply to changes in patient outcomes will help target quality improvement efforts, alongside other strategies that aim to reduce paediatric mortality in resource-limited settings .This study has highlighted numerous barriers to oxygen supply and delivery to paediatric patients in three Eastern Ugandan DGHs, from the points of view of healthcare providers. Healthcare professionals described lack of infrastructure, facilities and training to effectively deliver oxygen therapy but Pallisa DGH reported use of oxygen therapy which closely adhered to international recommendation. Quality improvement work prioritising oxygen therapy at government-funded district general hospital level should focus on site-specific aspects of oxygen supply and delivery and sensitizing communities to the benefits of oxygen. Further research in resource-limited settings surrounding oxygen supply and delivery will establish areas for continued improvement.


Research on insect–plant interactions has highlighted the intricacies of constitutive and induced plant defenses. Of particular interest has been the relationship of natural enemies  to herbivore induced changes to plants, especially their responses to herbivore induced plant volatiles (HIPVs). In recent decades this has been a fertile area for research, with elegant experiments showing that HIPVs are important in attracting natural enemies to plants. We critically appraise the application of work on HIPVs in plant–insect–natural enemy interactions. The promise of applications to improve pest management has not been forthcoming. We attribute this to a failure to include the multifaceted aspects of natural enemy–prey interactions – attraction, location, subjugation and experience. Attraction in an olfactometer by naïve parasitoids has not been translated to methodologically sound field-based estimates of higher parasitism rates. We highlight what needs to be done to better understand the information that HIPVs convey, how this is utilized by parasitoids and how a greater understanding of these interactions might lead to the development of new strategies so that this knowledge can be effectively deployed for improved pest management. A wide range of pathogens and sucking, chewing and boring herbivores assail all parts of plants in nature. Recent research has revealed the intricacies and sophistication of a Pandora’s box of chemical interactions that mediate plant responses to this attack see . Plants Following plant damage, induced direct defenses lead to localized and systemic elevation of toxic secondary compounds above constitutive levels, which affect the preference, performance and feeding behavior of herbivores . The incIn natural environments it is very likely that plants suffer sequential and/ or simultaneous attack by numerous herbivores and pathogens. Plant pathogens can suppress the host plant defenses that they induce by leveraging SA-JA crosstalk using chemical toxins and the virulent effector proteins they secret . In thisMelinis minutiflora or the forage legume Desmodium sp. and the planting of other grasses, e.g., Pennisetum purpureum or Sorghum vulgare sudanaense at the field margins (M. minutiflora or Desmodium sp. repel ovipositing stem borers from the maize crop (M. minutiflora themselves result in meaningful greater parasitism of stem borers on maize (Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) attacks late larvae of Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) (C. partellus and the non-host Busseola fusca (Fuller) (Lepidoptera: Noctuidae)   and naïvctuidae) , 1996.Figure 1A). These responses are typically modulated by parasitoid experience, such that experienced parasitoids orientate preferentially toward plants upon which they have previously successfully located and parasitized a host . Thus, although parasitoids might exhibit an innate preference for the volatiles produced by certain plants . Parasitoid orientation to a plant emitting volatiles that might be associated with the presence of host larvae is merely the first step in host location. Upon alighting on the plant surface, parasitoids typically become arrested , before increasing activity following the perception of post-alighting cues , intensifying their search around sites of herbivore feeding damage before locating, sampling and then parasitizing their hosts . The vast majority of studies that seek to manipulate the responses of plants to herbivory in order increase biological control of pests rely on the application of a plant defense response elicitor  with the express purpose of attracting parasitoids to treated plants. The importance of subsequent parasitoid behaviors  is then not considered, ignoring factors that are critical to successful host location and subsequent attack. For example, although the diamondback moth parasitoid, Diadegma semiclausum (Hellén) (Hymenoptera: Ichneumonidae), orientates toward and alights on intact, host-free cabbage plants treated with exogenous applications of JA, its post-alighting behavior is inhibited. Our work shows that the residency time of individuals alighting on JA-treated plants is the same as that of individuals landing and foraging on plants infested with host larvae . Furthermore, experienced individuals locate hosts much more quickly than naïve parasitoids, demonstrating the importance of post-alighting cues in successful host location . The lack of consideration of the subtlety and sophistication of the post-alighting chemical ecology of host–parasitoid interactions likely contributes to the dearth of examples where these strategies have been successfully deployed in the field. Further research to better understand these behaviors in parasitoids that are targeted for field manipulation by exploiting host–plant interactions for improved pest management are encouraged.Although naïve parasitoids can be attracted to the volatiles produced by plants that are attacked by their host herbivores, our work shows that they can equally be attracted to volatiles emitted by those plants when they are attacked by non-host herbivores, or even when they are induced by a chemical elicitor, such as exogenous JA , and where their foraging behavior is further disrupted by the absence of appropriate post-alighting cues , is likely to disrupt rather than facilitate the conservation biological control strategies into which HIPVs are integrated. Given these effects perhaps the ways in which HIPVs can be best deployed for improved pest management should be re-evaluated; rather than attractants to support conservation biological control, they might be best utilized as arrestants to complement augmentative or even inundative releases of natural enemies  (Lepidoptera: Noctuidae), such that they become more attractive to parasitic hymenoptera (Spodoptera frugiperda (J.E. Smith) could not be demonstrated  and predatory lacewing larvae . The increased attraction is temporary, and plants revert to their original level of attractiveness 3–4 days after the application of JA or a feeding event (B. oleracea plants in the field can manipulate the spatial patterns of P. xylostella oviposition (P. xylostella eggs can be concentrated for destruction.The introduction of synthetic HIPVs into crops can induce natural defense responses in nearby plants  and the enoptera  in labornstrated . Similarboratory . Howeverboratory . In addilostella , D. seming event . Selectiposition , raisingUnderstanding of the molecular basis of plant responses to herbivore attack has increased markedly in recent years, but the technologies that have been developed have not led to more effective use of natural enemies for pest management. This is at least in part due to an under appreciation of how natural enemies utilize and respond to the cues they perceive from herbivore damaged plants under field conditions. Simply deploying HIPVS to attract natural enemies has not worked, however, developing a better understanding of the ecology of these interactions will inform how HIPVs and other components of plant–herbivore–natural enemy interactions might be more effectively used in as yet untested ways.Figure 2.MF and MZ conceived and designed the overall study. GA, RS, and MF designed the experiments. GA and RS conducted the experiments. MF and MZ wrote the paper. GA did the artwork for The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


In this review we focus on the role of viscoelasticity in the control of collective cell migration in various cellular systems, mentioning briefly some aspects of single cell migration. We aim to provide details on how viscoelasticity of collectively migrating groups of cells and their surroundings is adjusted to ensure correct morphogenesis, wound healing, and metastasis. Finally, we attempt to show that environmental viscoelasticity triggers molecular changes within migrating clusters and that these new molecular setups modify clusters’ viscoelasticity, ultimately allowing them to migrate across the challenging geometries of their microenvironment.Cell migration is essential for a wide range of biological processes such as embryo morphogenesis, wound healing, regeneration, and also in pathological conditions, such as cancer. In such contexts, cells are required to migrate as individual entities or as highly coordinated collectives, both of which requiring cells to respond to molecular and mechanical cues from their environment. However, whilst the function of chemical cues in cell migration is comparatively well understood, the role of tissue mechanics on cell migration is just starting to be studied. Recent studies suggest that the dynamic tuning of the viscoelasticity within a migratory cluster of cells, and the adequate elastic properties of its surrounding tissues, are essential to allow efficient collective cell migration  HavingDrosophila border cells, for instance, need to resist the external pressure exerted by gigantic nurse cells and also open new spaces to migrate across them. To maintain a forward motion and to not collapse while moving across nurse cells, border cells increase their levels of E-cadherin as they delaminate and maintain these levels throughout migration [While these examples show how cells modify their AJs to fine-tune their viscoelastic properties in order to acquire fluidity, other migratory clusters are required to ‘defeat’ their environment while collectively migrating. These clusters maintain high levels of type-I cadherins or even increase these levels to resist deformation from external mechanical stress and to exert higher traction forces while migrating. igration .Similarly, during wound healing, epithelial cells rely on E-cadherin-mediated AJs to migrate in a coordinated manner. In these cells, the expression of E-cadherin is maintained because it plays an important role in the transmission of traction forces generated by an actomyosin ring during migration ,173. ColControlling cadherin endocytosis to regulate AJs dynamics has been proposed in many systems and is an incipient field of research for EMT and cell migration . The tim3.4via AJs adjustment during collective invasion. For this, cancer cells use a range of strategies, for instance during breast cancer invasion cells undergo EMT in a metalloprotease-dependent manner and then transcription factors will switch cadherins to reinforce EMT. In a first step, secreted MMP-3 metalloprotease cleaves the extracellular domain of E-cadherin leading to weakened cell-cell adhesion strength. Then, migration relies on Rac activation and the EMT transcription repressor Snail, which further reduces E-cadherin levels [Cancer cells also modify their viscoelastic properties to confront the environment n levels . This aln levels . EMT is n levels ,158. In n levels or Twist n levels  can leadIn vivo, cell–cell adhesion strength is not always enough to maintain collectiveness of mesenchymal migratory groups and additional mechanisms help cells to collectively migrate  migrate all over the fly embryo as single cells by transiently separating the interface between mesoderm and ectoderm. A recent article showed that the viscoelastic properties of their 3D environment are relevant for their invasive capabilities. This study shows that haemocyte invasion occurs in stereotypical locations, characterised by the presence of ectodermal cells with reduced cortical tension. These authors further demonstrate that tension in the ectoderm at this point was reduced in a mechanism that required the Tumour Necrosis Factor (TNF) activity [in vivo, single cell migration requires softening of the 3D environment. Another example occurs at late stages of development, during enteric system development. In this system, tissue viscoelasticity plays a dual role with an initial stiffening allowing neural crest-derivative cells to easily colonise the gut, however further stiffening reduces invasion rate. Collagen accumulation in the gut is the source of stiffening in this case and in order to keep migrating, cells constantly secrete proteases that help them degrade this dense matrix of collagen [in vivo [via cell accumulation underneath the neural crest in a PCP-dependent convergent extension movement of mesodermal cells, which starts early during gastrulation. Mesoderm stiffening triggered the onset of migration by promoting an EMT-like cadherin switch in neural crest cells, where N-cadherin was stabilised and E-cadherin levels reduced in stiff conditions. Once the onset of migration was triggered, stiffened substrate also provided an appropriate platform for neural crest cells to efficiently form actin-based protrusions which are required for their migration in vivo (in vivo measurements of tissue elasticity and fluidity/viscosity. In vivo measurements could deeply impact the relevance of our ex vivo/in vitro observations, by allowing the evaluation of cell behaviour and gene expression in a physiologically relevant context.Tissue viscoelasticity may represent a challenge for cells when they are already migrating. However, viscoelastic properties of the microenvironment can also play an instructive role in a wide range of processes which are just starting to be unveiled . In migrigration . The mecigration . While iactivity . This stcollagen . Viscoel[in vivo . Stiffen in vivo A. An imp4.1In vitro experiments show that durotaxis occurs in single and collectively migrating cells. The direction of fibroblasts plated on polyacrylamide substrates can be biased towards pulling forces or against pushing forces exerted on the gels. This was one of the first demonstrations suggesting that changes in tissue rigidity and strain could play a role in guiding migration of cells [in vitro. Monolayers of MCF10 A cells asymmetrically spread when plated on precisely designed stiffness gradients, with cells collectively spreading more efficiently towards stiffer parts of the gels. Cadherin-mediated AJs play a major role in the oriented transmission of forces that help cells to sense the gradient and achieve a global directional response [in vitro studies, they have the potential to be relevant for morphogenesis, cancer, and wound healing. Viscoelastic properties from the environment also play an instructive role during vascular remodelling, in which endothelial cells migrate against the shear strain generated by the blood flow [in vivo.Viscoelastic properties of the environment not only trigger the onset of collective migration and provide a permissive environment for migration. These increasingly intriguing external cues have been also proposed to work as a directional cue during single and collective migration in a process called durotaxis, which is defined as the directional migration of cells along a stiffness gradient. of cells . Later aof cells . Collectresponse . Althougood flow . In one ood flow . Altoget5in vitro and in vivo, the role of mechanical cues in the regulation of these transcription factors is comparatively less understood. Also, whether environmental viscoelasticity modulate EMT by controlling other aspects of this fascinating process such apicobasal polarity, cadherin turnover and MET is just starting to be unveiled (The extent of the effect of environmental viscoelasticity goes beyond cell behaviour, and several studies show that extrinsic mechanical cues lead to modification in gene expression. We have provided examples where AJs proteins are modified at transcriptional and posttranslational levels by a transient and reversible EMT, however the mechanisms underlying these modifications of cadherin content and the interplay of environmental mechanics with EMT-related transcription factors is just starting to be understood. Zeb, Twist, and Snail families of transcription factors are EMT transcriptional regulators that control the levels of Cadherin mRNA. Twist expression has been shown to be mechanically regulated during drosophila gastrulation, where external compressive forces induced ectopic expression of Twist ,215. Intunveiled .Fig. 5Ov6via EMT-regulated modification of AJs is essential to ensure efficient collective migration across tissues with physically challenging architectures. We also exposed that viscoelasticity of the migratory microenvironment is important to trigger cell migration, provide a substrate to allow efficient migration, and/or to guide migration via durotaxis. In addition, we examined new advances showing potential mechanisms mediating the translation of mechanical inputs into the cells, its effect on the expression of classic transcriptional regulators of EMT, and their effect on the modulation of the viscoelastic properties of migrating cells and their surroundings.Here we discussed examples showing that the adjustment of the viscoelastic properties of migratory cells in vivo [Drosophila haemocytes invade softer areas of the fly embryo [via secreted molecules, it would be interesting to study the interplay of viscoelasticity and secreted molecules in the coordination of collective motion, as part of this integrative vision of morphogenesis. In the future, the consideration of these types of mechano-molecular feedback interactions may become particularly important in the improvement of protocols aiming to generate organ-analogous structures such organoids. So far, this field has focused mostly on the combination of the right molecular components, with viscoelastic properties of the microenvironment only just starting to be considered [Examples of tissue interactions, such as the one showing that the EMT and collective migration of the neural crest are triggered by mesoderm stiffening in vivo , or the y embryo , invite nsidered ,226.in vivo rat models, it was shown that mechanical stress exerted by gastric tumours into their microenvironment lead to major molecular effects which correlate with poor prognosis [Furthermore, if we understand how these feedback loops operate in embryo morphogenesis we could consider applying this knowledge for more effective therapies when approaching major diseases such as cancer or when aiming for effective regenerative strategies. Using rognosis . Charact