Web-based Information Systems (WIS) are becoming increasingly necessary to provide support for users who are in different places with different types of information, by facilitating their access to the information, decision making, workgroups, and so forth. Design of these systems requires the use of standardized methods and techniques that enable a common vocabulary to be defined to represent the underlying knowledge. Thus, mediation elements such as traders enrich the interoperability of web components in open distributed systems. These traders must operate with other third-party traders and/or agents in the system, which must also use a common vocabulary for communication between them. This paper presents the OntoTrader architecture, an Ontological Web Trading agent based on the OMG ODP trading standard. It also presents the ontology needed by some system agents to communicate with the trading agent and the behavioral framework for the SOLERES OntoTrader agent, an Environmental Management Information System (EMIS). This framework implements a “Query-Searching/Recovering-Response” information retrieval model using a trading service, SPARQL notation, and the JADE platform. The paper also presents reflection, delegation and, federation mediation models and describes formalization, an experimental testing environment in three scenarios, and a tool which allows our proposal to be evaluated and validated.Modern  This involves the use of rules and standards for their construction and real-time operation, interaction, and interconnection. In this kind of systems, system “agents”  working in the same ambient (computing space), or even other third-party “agents”, interact. System convergence is possible through three basic parameters: (a) autonomy and intelligence (software agents), (b) a common vocabulary for all convergent systems (ontologies), and (c) trading between subsystems, necessary to enable, coordinate, translate, and maintain this common vocabulary (traders). The most recent Web Information Systems (WIS) have been developed under open and distributed paradigms using rules and standards for the construction and operation of real time interaction and interconnection [In a more open world, information systems must be flexible and readily adaptable, extendable, accessible, and operable by different people or groups of people who are in different places and have different types of information, facilitating access to information by decision-makers, workgroups, and so forth  [ environment has allowed real convergent systems to develop over time. EMIS are social and technical systems with a variety of final users and actors  who cooperate with each other and interact with the system for decision making, problems solving, and so forth. An EMIS uses normally knowledge bases distributed in space and time. Not only is this information used by human actors in the system but also coordinates web software (and autonomous) components requiring a common vocabulary . An example of web-based EMIS is the SOLERES system, a spatiotemporal environmental management system based on neural networks, agents, and software components [s (EMIS)  are a tymponents . Information System supporting environmental management. EMIS are a special case of Geographic Information Systems (GIS), though the granularity of environmental information is more specific . Furthermore, EMIS use a more advanced, more specific technology than geographic information systems; for instance, we use neural networks, multiagents systems, and cellular automata features.An EMIS is an Human and the Computer. Due to the nature of these systems (open and distributed), people organized in workgroups for decision making may be found in different places and be arranged by their profile . This sort of interaction  requires unified protocol and communication policies for all parts of the system. People and groups of people also interact through the system by using user interfaces (UI), which are generally well suited to their needs [Human-to-Computer, HC) also needs to establish communication protocols among users, profiles, groups, and user interface agents. Finally, these user interface agents act as mediators for people interacting with other system agents. This interaction  requires communication protocol, commonly known as choreography (or orchestration). All three of these types of interaction protocol  software have to know the knowledge semantics that manages each part of the system .Two basic roles interact in WIS: their needs . This ty interoperability of web components working in a WIS approach [Mediators (commonly known as “traders”) enrich theapproach , 7. Thesapproach .On the other hand, popularity of the WIS has led to an increasing volume of information available in information systems.Users depend on the web to meet their information needs through search engines, portals, digital libraries, and other information retrieval systems , 10. How Query-Searching/Recovering-Response (QS/RR). This mechanism is based on the traditional client/server model. On one hand, the term “Query” refers to the whole process of creating and formulating the client's question. The term “Searching” refers to the process of locating the repositories where the information is found, and the term “Recovering” refers to the process of locating, identifying, and selecting the data from the data sources . Finally, the term “Response” refers to the whole process of formulation, preparation, and creation of the response by the server to the client. The “Query-Searching” pair is a process that goes from the client to the server. The “Recovering-Response” pair goes from the server to the client.The main WISinformation retrieval mechanism is the traditionalUniversal Description Discovery and Integration) specification and WSDL (Web-Services Definition Language) for SOA  (Service Oriented Architecture) are based on theseclient/server implementations for web systems. Nevertheless, these techniques allow agents to respect a subscribe/publish/response model and a QS/RR information retrieval approach for locating WSDL documents  and connecting web services in WIS, but not for different types of information (non-WDSL information). Traders are another solution for open and distributed systems [http://www.omg.org/) (Object Management Architecture) ORB (Object-Request Broker) mechanism. Although traders are traditionally used as middleware for object interoperability, they can easily be adapted for interoperability of information and functionality. In respect to this, the use of functional ontologies in our work is a good solution for adapting traders to information retrieval in WIS. User information retrieval is an emerging area and a promising avenue for the design and implementation of a new generation of information retrieval systems, especially for new web-based EMIS due to the particularity and complexity of the information and users  [UDDI ( systems  that exttrators) . Ontological Web Trader (OntoTrader) as a mechanism for solving the complexity of information retrieval in the EMIS by means of a trading model for WIS guided and managed by ontologies. This kind of web service is a user-information search service based on a web QS/RR model. Therefore, OntoTrader is a new  information retrieval mechanism that implements a QS/RR model and uses the SPARQL query language and the OWL ontology description language to operate. This service is based on a user request action that identifies the agents involved and their communication protocols. In our system, the ontologies are used in two different contexts: (a) they represent the application domain information itself and (b) the services that some agents request from others during their interaction. Although a trader agent has five interfaces , this paper discusses only the behavioral and data ontology design features of the Lookup trader interface, which is used for searching and recovering user information in a QS/RR model. All research work presented here is part of a complete design strategy for Ontology-Driven Software Engineering (ODSE) that we are developing in SOLERES.In a sense, the SOLERES system , our EMIS model, follows a WIS approach –17. In t OntoTrader, a WIS information retrieval mechanism. In this part, we describe the Lookup interface ontology and the metadata template that the trader manages  in OWL and formalize them in UML.  OntoTrader formalization. Sections The remainder of the paper is organized as follows.  open world, information systems must be flexible and readily adapted, extendable, accessible and operable by different people or groups of people (convergent systems). The convergence of these systems may appear over time with the business needs of the system. For instance, a decision-making system in medicine, originally made up of two subsystems, may increase over time by connecting to other systems in networks which require/provide contents/services to the system service as a whole. The convergence of these systems is possible due to three basic parameters: (a) autonomy and intelligence, (b) a common vocabulary for all convergent systems, and (c) mediation between subsystems, necessary to enable, coordinate, translate, and maintain this common vocabulary. In the first parameter, software agent and multiagent system properties encapsulate traditional concepts of web components (or web services) with repositories of knowledge-based rules that work autonomously (endowing it with a certain degree of intelligence). These rules can be made and applied to agent groups that work in the same communication and behavior patterns (choreography). Ontologies are a good mechanism for establishing this common vocabulary necessary in convergent systems.The progress of the new technologies in web-based information systems is obvious. In a moreSemantic web is a good example of this. It standardizes the criteria, languages, mechanisms, methodologies, and platforms in universal web data semantics. Finally, trading services are a good device for communication-coordination (interoperability) between WIS subsystems as, for example, UDDI and WSDL in SOA. EMIS is an example of WIS developed during recent years. Experimentation with technological advances in WIS in fields like medicine, biology, and especially environment has allowed real convergent systems to gradually emerge. In the following sections, we analyze some relevant EMIS found in the literature and see how agents, ontologies, and trading services are applied, ending with a case study, the SOLERES system architecture, as an example of an environmental information system developed by the Applied Computing Group (ACG) at the University of Almeria, Spain [a, Spain . information management, agents can be used for searching for information (such as a database); they can filter results, recall them, organize, or even automatically distribute them.In control and supervision processes (monitoring), an agent can monitor a particular element or activity and respond to any event that may occur, for example, in transport system modeling and control or in industrial processes.InComputer Supported Cooperative Work, CSCW), where, due to their nature, agents can support the information flow necessary for the activity and interaction of group members.In cooperative work, group applications  in Web-based Environmental Information Systems (our main line of research).OntoTrader), http://jade.tilab.com/) (Java Agent Development Framework) to implement the SOLERES multiagent system because it simplifies the implementation of multiagent systems through middleware and provides a tool-set as support for depuration and implementation of open, distributed, and heterogeneous information systems.We used these four contexts to design and implement the QS/RR model for a web-based trading agent  from different sources and different ways of reasoning.There are several languages available for modeling knowledge domains , in partIn the literature, ontologies have been used to represent environmental knowledge. In , the autIn , the autExtensions of existing ontologies have also appeared in this knowledge domain. In , the aut trading function is one of the 24 functions of ISO/ITU-T ODP model [The Reference Model of Open Distributed Processing (RM-ODP) is a model jointly developed by the International Standard Organisation (ISO) and the International Telecommunication Union (ITU-T). This model defends the transparent use of services distributed in platforms and heterogeneous networks and dynamic location of these services. TheDP model . This sp exporters and those requiring capacities from the system objects are called importers (From the viewpoint of object-oriented programming (OOP), a trading function (trader) is a software object which serves as an intermediary between objects that provide certain capacities (services) and objects that require dynamic use of these capacities. From the ODP perspective, those objects providing capacities to other objects are calledmporters . legacy system properties in federated trader systems.A trading object uses five interfaces to interact with client objects (importer and exporter): Register, Lookup, Link, Proxy, and Admin. The Lookup interface allows clients to ask the trader about the services stored in the trading service. With the Register interface, clients can export services offered in the trader. The Link interface allows the trader to be connected to other traders . This enables the system administrator to connect his trader with other well-known traders and propagate requests in a network. The trader can also send the request to connected traders and locate new offers with the same searching conditions imposed on the target trader. The Admin interface allows administrators to configure the trader . The Proxy interface is used to enableThis section presents the main SOLERES system architecture, a spatiotemporal information system for environmental management (an example of EMIS). This system is supported by the application, integration, and development (extension) of multidisciplinary studies in satellite imaging, neural networks, cooperative systems based on multiagent architectures and intelligent agents, and software systems with commercial components. The general idea of the system is a framework for integrating the disciplines above for “environmental information” as the application domain, specifically ecology and landscape connectivity. The system has two main subsystems, SOLERES-HCI and SOLERES-KRS.  Computer Supported Cooperative Work (CSCW) paradigm and implemented using innovative intelligent agent technology and multiagent architectures. The system is designed to be used for cooperative environmental decision-making tasks by different people (systems users) arranged in different organization models . There may be politicians, technicians, or administrators, among others, who need to interact with each other and with the system.SOLERES-HCI is the framework specialized in human-computer interaction. This level of the information system is defined by means of theA user of the cooperative system has an intelligent agent  can be distributed, consulted, and geographically located in different ambients  called Environmental Process Units (EPU). Thus, the system is formed by a cooperative group of knowledge-based EPUs. These groups operate separately by using an intelligent agent to find better solutions .OntoTrader) based on the ODP trader specification [External_DB repository in <<OWLrepository>>). These EIM documents are the first level of information in the KRS subsystem.We accomplished the distributed cooperation of these EPUs by developing a web trading agent , or EID documents. These documents contain the most important EIM metadata that could be used in an information retrieval service and, furthermore, incorporate other new metadata necessary for agent management itself. To a certain extent, an EID document represents a “template” with the basic metadata from the EIM document data. The EID documents have also been specified by an ontology to accomplish open distributed system requirements. EID documents represent the second level of information in the KRS subsystem. Each EPU keeps its own EID document (or sets of documents) locally and also registers them with the OntoTrader (the web trading agent). This way, the OntoTrader has an overall repository of all the EID documents from all EPUs in an ambient and can thereby offer an information search service, as described further below.The second repository contains metadata calledThe trading service implemented and the requirements that it must fulfill to be considered open and distributed are described below. Afterwards, the structure and ontology used by the software agent responsible for this service (the trader agent) are explained.Trading is a well-known concept for searching and locating services. In a trader-based architecture, a client component that requires a particular service can query a matchmaking agent  for references to available components that provide the kind of service required. We based our work on the traditional functionality of a trader, but with adapting it to knowledge-based agents instead of objects (or software components). But first, let us see the requirements a trader should have. repository-based federation strategy makes it possible for different trading services to read and write in the same repository at the same time, each unaware of the presence of the others in the federation, and thereby allowing the approach to be scalable. On the other hand, the traditional “direct” federation strategy requires a trading service to communicate directly with the trading services with which it is federated. Although this federation-based scheme is very safe and effective, communication overloads increase with the number of federated trading services.Although the trading services could be compared to web search engines, in reality, web searches are more structured. In a trading service, the matching heuristics need to model the vocabulary, the distance functions, and the equivalence classes in a specific domain. For cooperation among web traders, trading services using different strategies should be able to federate. For example, aCurrent information searching and selection (recovery) use “hard” matchmaking operations which are too restrictive, and “soft” matching criteria are often necessary. In trading services, especially in independently extendable open systems , it must be decided whether “soft” or “hard” matching is required. A trading service should thus allow users to be able to specify heuristic or metric functions in the search, particularly in cases where matches are “soft.” For instance, the trading service could return results ordered by a search criterion or discard some search sequences in the repositories where they are carried out. request-response action, can refer either to a list of results that meet the restrictions imposed on the query or to a “failure” notice if the search could not find a solution. If a “failure” notice is returned, the trading service should also be able to demand that the query request must necessarily be satisfied; otherwise, the query request is stored, and the response is delayed. This request-response behaviour is called store and forward query. Finally, a trading service should also allow query requests to be delegated to other (known) traders if they cannot be satisfied by the current trading service.Furthermore, after processing, a trading service should respond to a user-query request (through a SOLERES-HCI interface agent) with a result. This result, found after aNow that the demanded requirements of the trading service have been identified, the service support structure can be described.As outlined in Ontologies are written in the OWL notation and formalized as a metamodel using UML class diagrams. We also use graphs to show details of relationships between properties. Throughout the explanation, these notations are used to refer to data or functionality ontology, though all three notations represent the same thing.  EID repository.As mentioned above, the trading service takes part in the search for environmental information based on the QS/RR model. As shown in Figures The system makes use of ontologies. Specifically, it distinguishes data ontologies, which represent the information in the domain on two levels, and service/process ontologies, which represent the actions that can be performed in the system, the information necessary to perform them, and the results of those actions. In SOLERES, the EIM and EID data ontologies, as well as the Lookup, Register, Admin, and Link service/process ontologies, are described, and they in turn are related to the mediation system interfaces. Classification). A cartographic map stores its information in layers (Layer), each of which is identified by a set of variables (Variable). For instance, we are using cartographic maps classified in 4 layers  with over a hundred variables .Classification), which is made at a given time (Time) by a technician or group of technicians (Technician). As a complement and formalization for graphs and metamodel, Satellite images work almost the same way. The information is also stored in layers, but here they are called bands. An example of satellite images are the LANDSAT images, which have 7 bands (but no variables are stored in this case). Finally, both the cartographic and satellite classifications have geographic information associated (Communication); (b) a parser that codes and decodes the trading ontology-based messages exchanged (Parser); and (c) trading itself (Trader). The third component is inspired by the traditional OMG trading object service specification concepts [  Lookup, Register, Admin, and  Link interfaces, but none has been implemented for the last one yet. The  Lookup interface offers the search-information in a repository under certain query criteria. The  Register interface enables objects in this repository to be inserted, modified, and deleted. The  Admin interface can modify the main parameters of the trader configuration, and finally, the  Link interface makes trading agent federation possible.The functionality of our web trading agent , 36 is dconcepts   from the trading agents. For example, a resource agent (belonging to a given EPU) could request the trading agent of the ambient where both are located to register a new EID document by using the  Register interface. Under these circumstances, how is this request between agents expressed? In SOLERES, this is done by specifying the service requests as ontologies. The ontologies used to describe services are known as “process ontologies,” and they are for three types of entities: concepts, actions, and predicates.As previously explained, this paper focuses on identifying and explaining how ontologies appear and intervene in the web trading agent service. Of the interfaces implemented, we only explain here how the  Lookup service ontology is query, which makes the search for EID documents according to specified prerequisites. The concepts identified in the ontology areQueryForm gives the information in the EID document necessary to make the query.PolicySeq represents the set of policies that specify how the search is to be made. These policies may affect the functionality of the trader during the execution time.OfferSeq refers to the set of EID documents that meet the query requirements. It therefore represents the result of the service requested.OfferSeqMach refers to the matchmaking process result. Results can be hard or soft solutions. The first one represents an exact solution  and the second one refers to a partial solution.In our system, an ontology has been created for each of the four interfaces (services) implemented by the trading agent. The set of all ontologies used for these trading agent services is called the trading ontology. Creation of specific ontologies for specific services allows the agents to use only the ontology that they need at any given time. Let us now see how the ontological web trading agent operates in the query process following the QS/RR model, since the query made by the user (or group of users) remains in the user interface until the results are retrieved.  <I,T,D>, each of which intervenes on a different level, depending on the treatment of the query. The implementation of these objects then corresponds to agents. Level 1 (L1) is like the client side. Queries are generated and dealt with by an interface object (I). Level 3 (L3) is the server side. System data (D) reside on this level. In our case, these are the EIM repositories with the environmental information. Level 2 (L2) is the middleware that enables the source information to be located. This is the level where the trader objects (T) operate. In our case, associated with the trader (T), the EID repositories with the source environmental information metadata (EIM) also reside there. All three objects use the Lookup ontology , where the three basic objects  reside, and the three trading models are permissible in OntoTrader, as described below. Trading Reflection model is a model for direct trading on the trader. The query may be solved directly by the trader. The query is generated on the interface and the information can be reached by the metadata that reside in the repository associated with the trader. In this case, the model  <I,T> pair intervenes.The Trading Delegation model trades indirectly with the trader. The query is partly resolved by the trader. A query is generated on the interface level that goes on to the trading level (T). The trader locates the source (or sources) of the source data (D) in its repository, inferring this information from its metadata repository. Therefore, the trader delegates the query to the outside data source (D). In this case, the object series intervening is  <I,T,D>.The Trading Federation model is a case in which two or more traders are able to federate. As in the cases above, the query remains preset on the interface. This query is passed on to the associated trader. The trader can propagate the query to another federated trader, who locates the external data source (D). In this case, the object series intervening is  <I,T,T,D>.Finally, theIn this three-level architecture, three different scenarios or trading models are possible: Query action and the query form concept  and a  uri (reference to the file where the query is stored). In addition, there could be a set of query policies (Policy) through the  Policy Seq concept, and each “policy” is represented by means of a tuple . For instance, some of the tuples implemented are def_search_card_Policy or max_search_card_Policy, indicating the number of records to be located by default and the maximum number of records to be located in the query, respectively. Possible exceptions are  𝒪 = {𝒪d, 𝒪f} and 𝒢 is a set of scheduling and control agents, where𝒪d is an OWL repository used by the trader,𝒪f is a set of five ontologies: 𝒪f = {ℒ, ℰ, 𝒟, 𝒦, 𝒳}, where ℒ is the ontology of the Lookup interface, ℒ ≠ ∅  (mandatory).ℰ is the ontology of the Register interface, ℰ ≠ ∅  (mandatory). 𝒟 is the ontology of the Admin interface. 𝒦 is  the  ontology  of  the  Link  interface.  𝒳 is the ontology of the Proxy interface. A web trader 𝒪d are related to ecological information repositories written in OWL. Ontological functions 𝒪f refer to trader functionality. There are at least two ontological functions: (a) the Lookup ontology (ℒ), which models the query made to the trader about information (templates) stored in the trading service, and (b) the Register ontology (ℰ), which models the export (register) of OWL instances in the trader. The three remaining ontologies are not mandatory in a web trader. The Link ontology (𝒟) models the interconnection of traders . An Admin ontology (𝒦) models the trader configuration . Finally, a Proxy ontology (𝒳) models the legacy systems properties in a federated trader system.In the framework of SOLERES system, ontological data 𝒞, a finite set of concepts: ℱ is a query form ℱ = {id, uri, type, source, target};𝒴 is a policy sequence, for instance: {def_search_cardPolicy, max_search_cardPolicy, exact_type_matchPolicy};𝒪 is an offer sequence 𝒪 = {id, uri};ℳ = {id, uri}.𝒜, an action 𝒜 = {𝒬} where 𝒬 is an input query action.𝒫, a finite set of predicates 𝒫 = {ℳ}, where ℳ is a returned message.ℛ, a relation of request.The Lookup interface of a web trader agent is defined as an ontology 𝒜 represents the set of possible actions , while ℱ is a concept related to a Query action, which represents the query made.UnknownQueryForm, PolicyTypeMismatch, InvalidPolicyValue, DuplicatePolicyName, and QueryError) or a successful action; that is, it has been performed satisfactorily (EmptyOfferSeq and NotEmptyOfferSeq).Predicates report any errors in the previous action ∪(ℱ × 𝒬 × 𝒴).Given a query form concept 𝒞) and actions (set 𝒜).The purpose of the relation of request is to define the relationships that exist between concepts  → M = UnknownQueryForm(a)  → M = NotEmptyOfferSeq(b) ( (c) Let us assume a given query 𝒬, a message http://tkrs.ual.es/SKRS/. Several different OntoTrader trading service functionality tests can be carried out in this environment. Behind it, the objects which comprise the OntoTrader system have been implemented by agents using the JADE platform. Three test cases, one corresponding to each of the three possible scenarios , were prepared. Below we explain some details of OntoTrader implementation, the framework of experimentation and testing, and the three case studies implemented.To evaluate the proposal, a specific environment was developed for experimentation, which is available at the website:   OntoTrader model levels  <I,T,D> were implemented by agents. The interface (I) was implemented by two agents: the  Interface Agent and the  IMI Agent. The trading level (T) was implemented by another two agents: Query Agent and  Trading Agent. The data level (D) was implemented by a  Resource Agent.For design reasons, the three basic  Interface Agent is the agent in charge of receiving the queries from the user over the user interface, transferring them to the  IMI Agent for management and returning the result to the user. The  IMI Agent acts like a hub between the user interface and the rest of the modules and is responsible for managing user demands. The  Query Agents are in charge of solving the information queries demanded. The  Trading Agents enable search and location of the information in the system and a filter based on the query parameters. Finally, the  Resource Agents are responsible for managing the information bases.TheScenario number 1 (reflection). The user query can be solved directly by a trading agent without the action of any of the resource agents.Scenario number 2 (delegation). The user query cannot be solved directly by a trading agent and requires the action of one or more resource agents.Scenario number 3 (federation). The user query can be solved by a federated trading agent or other trading agents with/without the action of a resource agent.Given the agent architecture, a multitude of scenarios could be suggested for processing a query made by a user. All the possible scenarios result in a combination of the three main scenarios which we have identified and used to evaluate and validate the proposal. OntoTrader model, which was implemented as a prototype for testing and validating the web trader agent implementation. Keep this figure in mind during the description of the three scenarios below.In general, the sequence of the three models is very similar, as follows. The sequence begins when a user writes a query from the user interface. The following section shows how a query from the user interface is constructed. Connected to the interface is an interface agent which is in charge of translating this query into the SPARQL query language. The requests that are sent between agents are constructed based on “QUERY-REF” forms in which the query is embedded in SPARQL. The results returned by the agents are constructed using “INFORM-REF” forms. We show some of these forms further below. The interface agent transfers the query to the IMI agent which is in charge of deciding which query model to follow  based on the type of data in the query. The IMI agent tells the Query Agent which path to take. The tests for the three scenarios (three paths) are shown below.Find the name of the soil science classification variables for the year 2008.” As mentioned, we show further below how a query is formed from the user interface (message number 1 in   QUERY-REF message which it passes on to the IMI agent. The message form is as shown in   :sender clause (line number 2), where the name of the agent sending the message is given , the  :receiver clause (line number 4) where the name of the agent that receives the message is given (in this case  IMIAgent), and the  :content clause which contains the content of the message. Observe how the query is made in SPARQL in the message content (lines number 7 to number 20). Finally, the  :language clause is where the type of language used to write the message content is given. In this case, it indicates that the content is written in SPARQL.A QUERY-REF form always has four basic clauses: theWhen the IMI agent interprets the query, it detects a query that can be solved directly by the trader (reflection model). The IMI analyzes the query sentence and the types of metadata in the trader repository to determine whether the query can be solved directly by the trader. If so, it resends this request to a Query Agent. In the case of the example above (Scenario 1), all the types of data in the query are available in the trader. The message to the Query Agent is as shown in   :content clause is a document in RDF. Specifically, the Lookup ontology is used for this type of request between agents. The message makes use of the “concept/action” pair in the ontology to formulate the query. Specifically, the concept  QueryForm (lines number 2 to number 11), where the query (generated in SPARQL) and the action to be performed, Query, are specified (line number 10), is used. Observe how the concept and action were defined in the ontology in   :language clause, gives the type of ontology used (line number 12). The new  :ontology  clause gives the path where the ontology is found.Certain parts of the message have been omitted to reduce its length in this paper. The OWL ontology is used to write the content of this message . The argument in the  QUERY-REF message similar to the one before, again using the Lookup ontology (sequence number 6), and sends it to the trading agent, which launches the  sparql query to its repository (sequence number 9), obtaining results. These results are returned to the Query Agent, constructing an  INFORM-REF form in this case, as shown in When the Query Agent receives this message, it infers that this query can be solved directly by the trading agent and generates a new  OfferSeq (lines number 4 to number 24) in the Lookup ontology shows the results found after processing the query. The action  Query (line number 26) and the predicate  NotEmptyOfferSeq (line number 25) show that the query returns a result, all of them in the Lookup ontology. If the query should not return any result, or if there were an error in the message constructed, the predicate  EmptyOfferSeq  or some predicates in the ontology indicating error would be used instead of the concept  OfferSeq, respectively.The ontology series “concept/action/predicate” is used to construct this message. The concept  INFORM-REF form with the headings  :sender and  :receiver . The IMI agent performs the same operation in turn, constructing its return form for the interface agent , which decodes the message and shows the results on the user interface, thus ending the trading reflection sequence in Scenario number 1.Then, when the Query Agent receives the results from the trading agent, it transfers them directly to the IMI agent, constructing a new “Find the minimum value of variable X used in information layer Y.” In this case, the result cannot be found directly in the meta-metadata that the trading agent stores in its repository and the metadata in the resource agent must be queried.  QUERY-REF  forms  . In this case, the above query generates the text in SPARQL shown in own) see .  split (sequence number 6) to prepare a double query. The first is the original query, which continues its course to the trading agent (sequence number 8). After querying its associated EID repository, the trading agent returns a message .This message states that the trader has found variable “E6” in its repository in document “EIM_0000000003” coded as “VAR_0000000202”. Notice that “EIM_0000000003” is a metadata  of an EIM resource found in a resource agent repository. This message is received by the Query Agent which generates a new message using the Lookup Ontology and applying a filter to the original SPARQL query with the data found in the last query (previous message). Specifically, the results are filtered for those documents that contain the variable called “VAR_0000000202.” This message is sent to the resource agent so it can complete the query by applying this filter. The new message (with the filter) is as shown in Finally, the sequence ends by returning the results between agents until arriving at the interface agent, which is in charge of displaying the results on the user interface.delegated federation” appears, that is, federation on the first trader and then delegation to the resource. There could also be a case of “multiple federation” where the system has been configured for queries to be propagated among federated traders if they cannot be satisfied.As mentioned, the federation-based model arises when the system has been configured for the trader to propagate the query to a second federated trader if the query could not be satisfied by the first. In this model, several different combinations are possible. One situation is that the second trader can satisfy the query directly in what is known as a case of “reflexive federation,” that is, a federation model on the first trader and in continuation reflection on the second. Another situation appears when the second trader redirects the query to a data resource (resource agent). For this case, a “ “Find the identifier of the classifications of city X in which there is information on variable V1 and variable V2.” From the type of query, the data may be found in the metadata of a trading repository. For this example, we assume that Variable V1 is a metadatum in the repository of one trader, and Variable 2 is in the repository of another.One possible query in this scenario could be the following:  QUERY-REF calls and their corresponding  INFORM-REF among the system agents is similar to those explained in the scenarios above . From this zone, it can be checked whether the result returned by the system is well constructed by making use of a standard external (third-party) tool, which does not belong to the system, called “Pellet.” Another capability enables the query made to be displayed in SPARQL. In order to validate the implementation, we have included a third capability which makes it possible to trace the messages exchanged by the different system agents. The traces of the messages exchanged among system agents after executing the query above are shown in the “Trace” tab see . These t  insertionOf (AND) and/or  unionOf (OR) type conditions may also be added. Once the query is executed, the result of its execution appears on the “Result” sheet, as shown in XML.Any type of complex system query can be constructed in the section “Complex Query.” This section is also divided vertically into two parts . On the The section “Graphics” of the website enables graphical display of the information repositories. A basic repository of the system may be displayed, or it is also possible to introduce a URL where an external repository is located. On the right-hand side of the window, an “applet” draws its content graphically. This “applet” can also make searches for concepts in the data ontology represented.For the validation of our environmental information system, the starting point is establishing certain “contracts” or restrictions to be evaluated in different areas of our framework. Each of these features has a series of restrictions that make it possible for the system implemented to function as desired . In the case of the trading function, a trader was designed and implemented following the standard RM-ODP specification, which enabled us to develop a trading system with the functions we required properly. The ODP trading standard was described in http://www.fipa.org/)  specification. FIPA is an IEEE Computer Society Standards organization that promotes agent-based technology and the interoperability of its standards with other technologies.Several different system objects (including the trader) were implemented as software agents using the JADE platform, which enabled us to validate their behavior, as well as their proper functioning. Furthermore, JADE is an implementation framework that complies with the FIPA  tool, a standard ontologies tool, and with this tool we were able to verify that the implementation of the ontologies is correct.Besides the trading and software agents mentioned above, the third key feature in the development of the TKRS is the ontologies  to which our data ontology and the SPARQL query made are sent as parameters, obtaining as a result the data that must be returned to the query. It also checks the validity of the ontology, warning if there is any type of error in it. TKRS implementation was checked with these five system features  evaluation techniques only examine whether information retrieval is done correctly and that the data are what was asked for.Furthermore, several sample scenarios were developed where the different types of query that can be executed were tested. In addition, a tool with which several evaluation and validation tests, predefined system queries, generic queries on system documents, display of the system document ontologies, and so forth, can be made was developed and is available on the web. The tool has a mechanism for agent message Distributed Information Systems (DIS) appear to provide the answer to these new requirements [Modern information systems are increasingly required to provide support for users who are in different places and have different types of data, facilitating access to information, decision-making, workgroups, and so forth.irements . Web-basirements , for insirements .EMIS, a type of WIS, have been under development in the last few years . The EMIOntoTrader), an extension of the traditional OMG trading service to support ontological information retrieval issues on web-based EMIS. The paper also presents three trading models for “information retrieval”: trading reflection, trading delegation, and trading federation.The present paper showed how traditional traders, properly extended to operate in WIS, are a good solution for information retrieval. An example of web-based EMIS is the SOLERES system, a spatiotemporal environmental management system based on neural networks, agents, and software components . In this OntoTrader model implementation using software agent-based approaches. This kind of web service is a search service based on a “Query-Searching/Recovering-Response” web model using the SPARQL query language and the OntoTrader ontology description language for information retrieval. This service is based on a user request action that identifies the agents involved and their communication protocols. Ontologies are used in two different contexts: (a) to represent the application domain information itself (data ontology) and (b) the services that some agents request from others during their interaction (process ontology). In this paper, we have described the process and data ontology design features of the Lookup trader interface. All research work presented in this paper was part of the completeOntology-Driven Software Engineering (ODSE) design strategy we are now developing in SOLERES. Implementation details and a prototype of OntoTrader are available at  http://tkrs.ual.es/SKRS/.We have also shown anFuture work will focus on several open lines of research. On one hand, we are studying the possibility of grouping all ontology management under a single agent (ontology agent). This agent would manage a database with all the ontologies used in the system and would code/decode them. This would considerably simplify the implementation of other agents and would provide more efficient management. Our work regarding the implementation of SOLERES-HCI (human-computer interaction) is also ongoing. This level of the EMIS is defined by means of the Computer Supported Cooperative Work (CSCW) paradigm  and implIn literature review, there are no approaches with enough similarities to make an empirical comparison between our processes and other existing algorithms. However, we intend to add some experimental comparisons with some isolated parts of other works, in order to highlight the advantages of our proposal. Finally, we would like to study, develop, and incorporate new evaluation and validation techniques, such as measuring the precision of data returned to queries, response time in executing the query, and usability.


On the occasion of the 60th anniversary of the publication of the DNA double helix and the 10th anniversary of the completion of the Human Genome Project, the value of genomic information to medicine continues to be widely debated. When the human genome was first sequenced it provided a “reference sequence,” an incomplete composite based on DNA from many different individuals, and the promise that it would revolutionize medical research and clinical practice. Figure Mutation detection for clinical diagnostic purposes is rapidly evolving from single disease gene testing to candidate-gene panels, to whole-exome sequencing (WES), and on to whole-genome sequencing (WGS). I have no doubt that highly automated WGS will supersede WES because it offers a more complete coverage of the genome, including all exons – beyond those captured on current exon arrays – all regulatory regions and noncoding RNA genes. Academic and commercial company scientists are making rapid progress in the filtering, interpretation, and annotation of WGS data.As newborn screening has expanded from a handful of tests to quantitative data on compounds of known or unknown identity by tandem mass spectrometry, a global method, so will WGS be done on cord blood samples routinely collected at the time of delivery. It has been proposed that the information be stored and scrutinized over time for age-appropriate information. I would argue, however, that the discovery of highly penetrant BRCA or other cancer gene mutations via newborn screening is of great relevance for adult relatives who may be at high cancer risk without knowing it. The highly charged ethical debate about which “incidental findings” – discovered via a physician-ordered sequence-based diagnostic test – to share with patients and their families will become moot when in newborn WGS screening, or in screening of healthy individuals in general, all abnormal results are “incidental” and generalized standards for informed consent and appropriate counseling will be in place.Looking ahead, as genome sequencing becomes widely available, how will genomic information affect the theory and practice of medicine? First, I do not think we need a new genetics subspecialty called “genomic medicine” or a “clinical genomicist” as a new professional specialist. Another model would be an interdisciplinary clinic staffed by experts in medical genetics, genetic counseling, molecular genetics, bioinformatics, and bioethics, possibly with individual members able to cover more than one area. While academic medical centers may experiment with establishing such “Genomic Medicine” clinics where people can take their genome data and receive interpretation, counseling, and referrals to disease-specific medical specialists, this approach does not seem scalable, mostly for manpower and reimbursement reasons.In reality, I believe genomics will enter medicine, as other new technologies have done, one specialty at a time, with variable speed and impact. Eventually, all healthcare providers will have to learn to incorporate genomic data, together with clinical, imaging, and standard laboratory data, in work-up and treatment plans. The newly discovered abundance of genome variants, copy number variants (CNVs) and single nucleotide variants (SNVs) – with detrimental, benign, or unknown effects on gene function and phenotype – are best interpreted in the context of medical knowledge of the disease and the individual's personal and family medical history. Risk prediction algorithms incorporating polygenic scores, as well as diagnostic and therapeutic decision trees, will be developed by panels of experts to help the front-line clinicians. Genomic data provide genetic risk estimates. But most diseases result from the combination of genetic and environmental factors, in an additive or interactive fashion. Therefore, knowing one's genetic risk is a great motivator for life-style changes with the goal of minimizing nongenetic risk factors.Oncology is the leading specialty in applying new cancer genomics information. The number of genes and pathways implicated in the predisposition and development of neoplasias is truly staggering. Tumorigenesis can be driven by mutations in one or more of ∼140 different genes that function in 12 different signaling pathways controlling cell growth, survival, and genome maintenance  that increase the activity of the mitogen-activated protein kinase signaling pathway. Following treatment with drugs that specifically inhibit mutant BRAF, tumor and metastases literally melted away. But the disease invariably relapsed a few months later  the Cross-Disorder Group of the Psychiatric Genomics Consortium  discoverAnother emerging theme is that “common diseases” may not be single disorders at all, but include a collection of rare disorders with similar overlapping phenotypes that are distinguished by the underlying genetic causation. As genomic information infiltrates various areas of medicine, it will lead to fundamental changes in disease classification, diagnostic concepts, and therapeutic approaches.Finally, the patient–doctor relationship will be drastically changed by the consumer empowering movement. As people gain greater access to their health information, including genomic information, and to tools allowing them to monitor their health parameters, they will increasingly become partners in managing their health. We are on a fast-moving train and the destination may surprise us.


The same year, 1939, the author elaborated in a letter that his goal in writing the book was “to rip a reader’s nerves to rags” by laying bare the life of the Dust Bowl migrants with whom he had spent time. Oklahoma Congressman Lyle Boren called the book “an infernal creation of a twisted distorted mind.”After Congress passed the Homestead Act in 1862, thousands of settlers moved to the semi-arid grasslands of the North American plains to farm and graze cattle. They plowed the fields and planted dryland wheat. High demand generated the promise of economic development and brought in more powerful plows, further expanding arable land. The grasses receded, leaving the ground exposed and vulnerable. When the drought came in 1930, strong winds whipping across the plains created severe dust storms, which continued for nearly a decade, moving millions of tons of topsoil and wiping out farms and ranches across 19 states in the heartland, which became known as the Dust Bowl.“And then the dispossessed were drawn west―from Kansas, Oklahoma, Texas, New Mexico; from Nevada and Arkansas, families, tribes, dusted out, tractored out. Car-loads, caravans, homeless and hungry; twenty thousand and fifty thousand and a hundred thousand and two hundred thousand,” Steinbeck wrote. Eleanor Roosevelt was less critical of his literary account, “The book is coarse in spots, but life is coarse in spots.”The Gleaners, a painting of peasant women gleaning a field of wheat after the harvest, foreshadowed Hogue’s lifelong interest in rural society and the land. He attended the Minneapolis College of Art and Design and took lessons from Clarence Conaughy and the muralist Lauros Phoenix.In 1898, Alexandre Hogue’s family moved from Memphis, Missouri, where he was born, to Denton, Texas, where his life and art would later become inextricably connected with the Dust Bowl. His early copy of Millet’s Hogue spent time in New York, absorbing the art scene and forming his own philosophy as painter, lithographer, printmaker, and muralist. “The true artist in painting or any other aesthetic expression sets out to express himself in terms of life he really knows.” He denied lasting influence from any training or external source. “I was considered a dead-on radical when I was young.”After a 4-year stint in the big city, Hogue became a vocal member of the Dallas Nine and their circle, a group of artists active in the mid-1920s. Other well-known members were Jerry Bywaters, Otis Dozier, Olin Travis, William Lester, Everett Spruce, Thomas Stell, Perry Nichols, Harry Carnohan, and John Douglass. These artists believed in creating their own idiom by portraying the local scene.Beginning in 1926, Hogue spent time each year in New Mexico, until the beginning of World War II. There he met founding member of the Taos Society of Artists Ernest Blumenschein and American masters Joseph Imhof, Victor Higgins, Emil Bisttram, and Buck Dunton. He made sketching trips into Indian Territory and became acquainted with Indian culture. For creating lasting art, Hogue believed, a feeling for the locality was more important than the natural beauty of the area.In the 1930s Hogue painted his Erosion series, depicting the devastation of the Dust Bowl, which he witnessed firsthand, “both before and after the dust menace, working and painting on a Panhandle ranch near Dalhart.” It had been “Plowed in on all sides by the ‘suitcase’ farmers, whose uncontrolled loose dirt, pushed before the wind, has gnawed away every sprig of grass that dares show above ground.” When the images appeared in national magazines, reaction was mixed. “Such misinformation will undoubtedly cause tourists and others to abandon or postpone visits to the many important and interesting points in the State of Texas.”Drouth Stricken Area, “The windmill and the drink tub are taken from life,” he wrote. “I worked on that windmill. In fact I was knocked off it by lightning. It was the windmill that was on my sister and brother-in-law’s place―the Bishop Ranch near Dalhart, Texas. The house was strictly my own. I just depicted it so it would be typical of the time…. The placing of a top of a shed coming in front of the tank is strictly a matter of composition. The whole thing is just visually built.”Hogue described his work as “psycho-reality,” involving “mind reactions to real situations, not dreams or subconscious.” He converted his thoughts into abstract visual terms, which were stronger than nature itself. In his work is most unpleasant. To record its beautiful moments without its tragedy would be false indeed. At one and the same time the drouth is beautiful in its effects and terrifying in its results. The former shows peace on the surface but the latter reveals tragedy underneath. Tragedy as I have used it is simply visual psychology, which is beautiful in a terrifying way.”“Some may feel that in these paintings… I may have chosen an unpleasant subject, but after all the drouth Dust Bowl, on this month’s cover, the footprints and tire tracks leading away from the farm denote those who fled, the “exodusters.” The angular shapes of fallen fence posts and tangled barbed wire mimic the blood-red wedge of thick dust against the sky. Along the rippled earth, a diminishing truck tire mark suggests that the family has just moved away, their traces already fading in the dust.In the More people actually stayed on their land than left, and many died of malnutrition and dust pneumonia―not the only illness eventually associated with the dust. Many discoveries about coccidioidomycosis arose from careful epidemiologic and clinical investigations in California’s San Joaquin Valley during the 1930s, when people migrated there from the Dust Bowl, and during the 1940s when World War II brought military recruits, prisoners of war, and persons of Japanese descent to camps and other areas where the disease is endemic.Now reemerging, coccidioidomycosis is sometimes called San Joaquin Valley fever or Valley fever. It is caused by a soil fungus found in the southwestern United States, mostly California and Arizona, and in northern Mexico and parts of Central and South America. Dormant during long dry spells, it develops as a mold when the rains come. Spores are swept into the air when the soil is disrupted during construction, farming, earthquakes, or other dust-cloud generating events and are inhaled into the lungs, where the infection begins.Life magazine called me, ‘painter of the Dust Bowl,” proclaimed Hogue even as he urged farmers to cooperate with federal soil conservation efforts. “My paintings are as much a statement of what may happen as what has happened―a warning of impending danger in terms of present conditions.”“I don’t like to be called a ‘regionalist’ or ‘American scene painter,’ or, as Continued economic development changes the land and draws new populations into disease-endemic areas. In the past decade, state-specific increases in the number of reported coccidioidomycosis cases have been observed in Arizona and in California, where hospitalization costs are increasing. Hogue’s ecologic concerns still apply because, as much as it is vital for creating lasting art, understanding the locality is indispensable for deciphering disease emergence, which is so much a circumstance of time and place. Steinbeck understood the complexity: “The land is so much more than its analysis.”


Crack use is prevalent across the Americas, and specifically among marginalized urban street drug users in Brazil. Crack users commonly feature multiple physical and mental health problems, while low rates of and distinct barriers to help service use have been observed in these populations. This study examined profiles and determinants of social and health service utilization, and unmet service needs, in a two-city sample of young (18–24 years), marginalized crack users in Brazil.N = 160 study participants were recruited by community-based methods from impoverished neighborhoods in the cities of Rio de Janeiro (n = 81) and Salvador (n = 79). A mixed methods protocol was used. Participants’ drug use, health, and social and health service utilization characteristics were assessed by an anonymous interviewer-administered questionnaire completed in a community setting; descriptive statistics on variables of interest were computed. Service needs and barriers were further assessed by way of several focus groups with the study population; narrative data were qualitatively analyzed. The study protocol was approved by institutional ethics review boards; data were collected between November 2010 and June 2011.The majority of the sample was male, without stable housing, and used other drugs . About half the sample reported physical and mental health problems, yet most had not received medical attention for these problems. Only small minorities had utilized locally available social or health services; utilization appeared to be influenced by sex, race and housing characteristics in both sites. Participants cited limited service resources, lack of needs-specific professional skills, bureaucratic barriers and stigma as obstacles to better service access. However, most respondents stated strong interest and need for general social, health and treatment services designed for the study population, for which various key features were emphasized as important.The study contributes substantive evidence to current discussions about the development and utilization of health and treatment interventions for crack use in Brazil. Based on our data, crack users’ social, service needs are largely unmet; these gaps appear to partly root in systemic barriers of access to existing services, while improved targeted service offers for the target population seem to be needed also. Crack use is prevalent across the Americas. Since the early 1990s, crack use has widely spread in cities across Brazil, and has become prevalent among street drug users . While nDrawing on both data from Brazil and other settings in the Americas  where crack use is also common, it is evident that crack users typically feature extensive health and social problems, even when compared to other illicit drug users -11. For Based on the common profile of extensive social and health risks and problems, crack users consequentially are in high need of appropriate social and health services and interventions -35. In BEvidence, however, suggests that only small proportions of drug users do access or receive the social or health (including treatment) services they need. For example, North American data suggest that only limited proportions of problematic drug users receive basic social or health services -43, and This multi-methods study examined aspects of social and health service utilization among a sample of young marginalized crack users in two Brazilian cities . Specifically, the study aimed to: 1) describe the utilization of key social and health services and identify factors associated with service use based on quantitative data; and 2) examine experiences, factors and dynamics of service access and use on the basis of qualitative data.The study [for details see Cruz et al. ] relied The study’s eligibility criteria included: 1) crack use on three days or more per week in the last three months; 2) 18 to 24 years of age; and 3) consent to participate in all study elements. Individuals either acutely intoxicated or experiencing acute mental health problem episodes, or displaying aggressive or other problematic behavior that would impede assessment were not included. If eligible, study participants were guided to the community-based local study offices  for assessments.Individual assessments were conducted in a private space in the local study sites, following the participant’s informed written consent. Quantitative assessments consisted of an interviewer-administered questionnaire with 31 items on socio-demographic and drug use characteristics, and health and treatment service needs. A total of 175  individuals were screened for study eligibility , and a total of n = 160 study assessments (81/79) were completed between November 2010 and June 2011. All data were sent to the Oswaldo Cruz Foundation (FIOCRUZ) for processing and analysis. Questionnaire data were scanned using Teleform® procedures and manually quality-checked; statistical analyses were performed using STATA v.9. Descriptive analysis for key social-demographic, health and drug use, and the main social, health and treatment service variables of interest were reported by site. Then, exploratory analyses of univariate associations between ‘any health or social service use in the past 30 days’ (collapsed omnibus variable) and select variables of interest (identified from existing evidence and experiences elsewhere) were conducted by site, including: Sex, age, ethnicity, housing status, education level, arrest history (past year), length of crack use (in months), sexual risk behavior (sex without condom in the last 30 days), current alcohol use (past 30 days), self-rated physical health, self-rated mental health, and oral sores, burns or wounds (last 30 days).Qualitative data on utilization, barriers and needs related to social, health and service utilization were collected from a total of 12 focus groups , 8 in Rio de Janeiro (n = 31) and 4 in Salvador (n = 13), with a numeric range of 5 to 8 participants per focus group, conducted in community-based settings between June 2011 and August 2011. There were several focus group participants who participated in more than one focus group in both sites, in order to allow to explore key issues in adequate depth, and hence included repeat participants. The focus groups were led by trained facilitators, following a semi-structured guide of key questions (see Appendix 1), which had been pilot-tested and adapted following results. The focus groups had a median duration of 30–45 minutes; their content was audio-taped and transcribed. The narrative data from the transcripts were manually coded and organized by the major emerging themes, organized and extracted through a systematic and reflective process , mainly The study protocol was approved by the Ethical Review Committee, Institute of Psychiatry, Federal University of Rio de Janeiro as well as the Brazilian National Ethics Committee (CONEP 519/2010).In terms of key socio-demographic characteristics, the mean age of the samples in both study sites was 21 years . The mean length of crack use was 46 months  and 55 months , respectively. As displayed in Table While half the sample reported good or better physical health status in Rio, a quarter did in Salvador Table ; just unEach of the available social or health services were only utilized by small minorities of the local samples Table . In Rio,The self-rating of specific service characteristics potentially influencing the utilization of social or health service offers  in the two local study samples found the following associations. Specifically, sex  was significantly associated with service utilization in both sites ; furthermore, length of crack use in Rio (p < 0.018), and unstable housing status in Rio (p < 0.054) were borderline associated with service utilization. A final multivariate analysis of these factors’ associations with service utilization was precluded due to the small sample sizes and overlapping confidence intervals.The qualitative results from the focus groups were separated into two initial categories, namely data on a) physical and mental health care, and b) drug abuse care.“[The] last time I went to a health services…it was very distressful, because the lines are very long…if someone needs a bandage for the foot or help to extract a tooth, there are too many lines, the person is humiliated in front of everybody and if I am under crack intoxication it is even worse, in this case I don’t wait in the line, I leave right way…” Similarly, another participant elaborated: “Some time ago I went [to a health service], I had dengue, with very high fever. The health service closed and I was not attended”. [Note: All quotes have been translated from Portuguese into English by the authors].Almost all respondents in both sites suggested that they only seek physical health services in case of emergencies, choosing not to try and access such services for preventive or non-emergency reasons. In Salvador, most respondents reported general health care access barriers such as: long wait times; closure of service before patients are seen; lack of doctors, dentists and other professionals; lack of resources . As one participant explained: “Hey crack man, get out! This is no emergency room!”In contrast, some respondents in Rio reported they were satisfied with the care provided by the health services they used, but complained of prejudices by health service professionals encountered by homeless patients . A participant illustrated how he experienced this: “[…] where I live is a community health centre where I usually get condoms…to avoid the diseases. But there is no dentist. And I think that this is very wrong because all crack user need a dentist. If there is no dentist the teeth will be gone, will get rotten”.Participants also cited excessive bureaucracy  and high transportation costs in order to get to and access services. A few respondents in both sites stated a desire that there should be basic clinical care services, such as dental and laboratory examination . Moreover, they stated a desire for better and more psychiatric and psychological treatment services for mental health problems experienced in the context of crack dependence. One participant described: “After smoking, I get depressed, I think about my family, I am here using drugs and my kids are far way, I become regretful because I had used. Then sometimes, I stay one whole day without using, I won’t use crack anymore, I will only smoke pot and all that. But when I get money, then it is like a disease, the desire arrives immediately, the craving, then I use it again, then the sadness hits my again – shit, I had fifty Reais and I spent it all on crack, I did not even buy no food ─ then the sadness, the regrets come again, do you get it? It is like that”. Another one emphasized what his/her desires were: “One year from now, I intend to be free of this drug, without a trace of it…one year from now I would like to be working, to have a family, to have a good job, to be what kind of person […] to be admired by my family. What I think for one year from now is that…to be alive!”Virtually all individuals in both sites reported intense desires to stop using crack. One participant elaborated on their experience: However, respondents demonstrated little knowledge about the availability of or access procedures to drug abuse treatment facilities, and mostly were under the impression that there is a severe lack of such services. Conversely, most participants perceived there to be several shelters available in their cities that were prepared and open to receiving crack-addicted individuals. However, they considered those shelters rather unsuited to help or support the treatment of their addiction problems, also because they were considered dirty, disorganized, without leisure activities (for distraction) or longer-term treatment resources that would enable them to abstain from crack use.“[…] It was a pig stall! […] On the streets, at least you can look for a clean place to sleep, but in that shelter no, you have to sleep there…in that filthy place…you have to use that stinky bathroom…I don’t even want to remember that.” Yet then, there were some discordant voices who saw good sides to the shelters: “But the food there was good” and “It is better to sleep there in peace […] than to sleep in the streets doing shit”.One of the participants recalled that he entered a shelter and left shortly after because “… [The] drug abuse facilities do not have a television set. What they should have? A sports area, some computers for the users to learn something, to get a job, what else? A car repair shop, so that the users would leave with a job…so to be able to have good food, every day”.One Salvador participant explained: Several participants from Salvador reported ongoing active crack use within such services. Respondents in Salvador also reported expressions of prejudice by drug addiction service professionals, saying that many professionals were not skilled or qualified to treat their addiction problems.“[…] What is missing there, it is not so much with the doctors, but with the people who work there…they were trained to do what? […] In many health centres, when the person gets there, the employee who will attend you is looking at you angry, many times turning their back on you, talking on the cell phone. So we may die there and he is talking on the cell phone, I think it is completely wrong, it is a lack of training”.“[…] If the person has easy access to the streets…he may relapse…so the person has to be in inpatient treatment [in order for treatment to work]” and “crack use has to be controlled [because] if you have access to it, you will use it”.Almost all participants in Salvador suggested that effective crack addiction treatment needs to start with inpatient treatment, including access to appropriate medications to support abstinence from crack use. Numerous respondents illustrated that because of the overwhelming cravings and desires to use crack in the context of addiction, they are not successfully able to continue and complete treatment if they have easy exposure or access to environments where they usually consume or buy crack. As two participants explained: Some respondents from Rio echoed these observations, although not in as large numbers as observed in Salvador. Rather, most respondents in Rio reported the desire to be able to freely access and leave services or shelters as they wished and felt necessary.“Talking about the schedule needs, there are different kinds of crack users. Some crack users are homeless, some have houses, some users go to the gutter, start to use on and on, so it is necessary to be different kinds of services…”.Virtually all respondents in both sites voiced a desire for availability and access to addiction services that were available 24 hours a day, 7 days a week in order to effectively address their service needs in the context of their strong and omnipresent compulsions to use crack. Given the large proportion of homeless individuals in the samples, the need for shelters exclusively for crack users was also widely voiced. As one participant stated: “[There should be] movies that everyone could watch …to have a course…those courses about informatics, something to occupy the mind!”Similarly, the vast majority in both sites stated a strong need for addiction treatment services with resources and programming – including leisure, games and sports activities – to distract crack users’ minds from their ubiquitous and strong cravings to use crack. As one participant stated: “[We should have a] way of making money, with something that we like to do […] and after work, to have a time of leisure, do you understand? To do things that occupy the mind!” and “I would like to go back to work! I would like to get my job back, to be trained […] to be able to go back to school!”Most respondents also suggested that addiction treatment facilities should include and offer educational or professional courses in order to help with their social reintegration and to keep them away from the dangerous lure of crack use as part of effective recovery. Two respondents explained their desires: “[…] And doctor, if everything that I and my friends said here existed, I guarantee to you that I would sign a commitment and would enter this treatment center right now. Because I really don’t want to just be using crack. If I have a choice, I will not die because of crack. I really want to quit yet all that we just mentioned is lacking”.All respondents also demanded that addiction treatment services should be staffed by professionals who are better trained, skilled, open, respectful, specialized in addiction treatment, capable of understanding the difficulties and severity of the experience of crack addiction, and sincerely willing to help them in rebuilding their lives. One Salvador participant expressed: Some respondents in Rio furthermore stated that the existence of strict rules and schedules within their treatment programs would be necessary and helpful to increase the prospects of positive treatment outcomes. Some respondents voiced a desire to be able to smoke marijuana in the context of crack addiction treatment, as the use of marijuana would reduce their craving for crack and help them with their sleep and appetite.This study examined patterns, determinants and unmet needs of health and social service utilization in two samples of young crack users, recruited from impoverished communities in Rio de Janeiro and Salvador, by drawing on multi-methods data. In addition to characteristics of social marginalization – as indicated by high proportions of unstable housing as well as exposure to law enforcement – our samples featured  comparably long histories of crack use, and high prevalence of use of other drugs as key risk factors for health problems ,22,57. TSubstantive pluralities of study participants in both sites reported both compromised physical and mental health statuses and, correspondingly, high rates of physical and mental health problems; large extents of problems in both these categories were seen as linked to participants’ drug use. Irrespective of the specific nature of these health problems, these general results are in line with findings from other studies confirming the common occurrence of diverse, overlapping and commonly chronic physical and mental health problems among marginalized drug user populations, and specifically crack user populations ,26,59,60In the context of high rates of physical and mental health problems in our sample as a first key finding, a second cluster of relevant findings is that our samples’ overall utilization of various social or health services was markedly low. This confirms widely observed patterns of low social or health service utilization in different jurisdictions and settings ,61,62. MThese results strongly suggest a situation of substantive discrepancies or gaps between apparent physical and mental health needs, and service utilization among the two local samples of young Brazilian crack users included in this study. This situation naturally provides grounds for considerable concern, as many physical or mental health problems reported among marginalized street drug users can be chronic and/or severe, and are associated with extensive disease burden ,63-65. AMainly drawing on our qualitative data, our results suggest that in regards to the services available, the vast majority of participants do not see these services well-suited for their needs, and they do not see themselves well-served in these facilities. While some of these barriers appear to relate to general problems, like lack of service capacity or resources, others refer to mundanely practical or bureaucratic issues  that are proven to affect marginalized populations more tangibly than others. Notably, participants also emphasized that they perceive many service providers not to be adequately prepared, qualified or experienced to deal with addiction-related health problems , or simpIn Brazil, health and drug abuse treatment services are offered and organized in different ‘networks’ of services, including institutionalized  and community-based care . Most oComplementing our study’s results indicating substantive service access and utilization gaps among crack users, it offers important evidence on the study population’s acute needs in these realms. Concretely, substantive majorities of participants in both sites reported that they, if available, would utilize basic social or health services specifically designed and tailored for drug users. Details of our quantitative data list a number of key components – ranging from both basic existential  and social support services to specialized health and addiction care services, yet also access and control features – that are considered important to make such facilities appealing and attractive for utilization see Figure 1. These mentions underscore the study populations’ needs for basic and existential social and health care that have also been reported for similar populations in other contexts ,42,84-87Notably, our qualitative data especially emphasizes a strong need and desire for adequate addiction treatment or care services among the study participants that would allow them to effectively address and treat their substance use problems, primarily crack addiction. While it is important to recognize that desires for addiction treatment or care are commonly present yet also differ in specifics in this population, it is principally disconcerting that most users currently do not see adequate treatment service or options available to them. As noted elsewhere, crack abuse or dependence is a form of psychoactive drug use for which few standard and commonly available treatment interventions exist -91. HoweThis study has some important limitations. It is based on local convenience samples, which may involve participation bias, and not be representative of crack user populations in the study sites, or elsewhere in Brazil. Data are based on self-report, which may influence validity, although great care was exercised  to address key sensitivities; validity in studies relying in similar approaches has been found to be good .Based on the above, our study provides major implications for policy and practice as related to social and health service development and implementation for the large populations of crack users in the two Brazilian study sites (and likely reflect similar situations in other Brazilian cities). While our study samples were characterized by high levels of physical and mental health problems, and substance use co-morbidities, current health and social services are largely perceived to be inaccessible, inadequate or unappealing; in addition, special interventions designed to meet crack users’ service needs – also concerning addiction treatment – largely appear to not exist. Given the high prevalence of and extensive health problem burden related to crack use in Brazil, these service gaps urgently need to be ameliorated with targeted and effective measures. This will need to include tearing down and addressing key barriers and obstacles to utilization of existing services, yet also the development and implementation of new and better social, health and treatment service options for the target population.1. Which kind of health facilities have you used recently? Tell us about the last time you went to a health service. What was your experience like?2. Have you had any difficulties in the last service you used? If yes, which difficulties? In case there were no difficulties with your last visit, have you ever had any difficulty when using a health service?3. Which services for drug users would you like to use and how do you think those services should be designed/what should they offer?4. How do you think that, for yourself, good addiction treatment should be offered and done? For example, which services and activities should be included? Who should provide the treatment? Where should it located?5. What would be the best access and service arrangements ? How would you like to use the service, e.g. how many times a week, which days/hours?6. In other interviews, crack users told us that drug abuse treatment facilities should provide referral to shelters. How should such shelters be designed and operated in order to work for you? Have you ever been in a shelter? What was your experience like?The authors declare that they have no competing interests.MC, TA, EL, FB, BF designed and co-led the study and the analysis plan. NB, LL and CB co-executed literature reviews and assisted with quantitative and qualitative data analyses. BF led the write-up; all authors reviewed and substantively contributed to draft revisions, and approved the draft as submitted. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1472-6963/13/536/prepub