Analytical Model of ALOHA and Time- and Frequency-Asynchronous ALOHA with Forward Error Correction for IoT Systems.

The blooming of internet of things (IoT) services calls for a paradigm shift in the design of communications systems. Short data packets sporadically transmitted by a multitude of low-cost low-power terminals require a radical change in relevant aspects of the protocol stack. For example, scheduling-based approaches may become inefficient at the medium access (MAC) layer, and alternatives such as uncoordinated access policies may be preferred. In this context random access (RA) in its simplest form, i.e., additive links on-line Hawaii area (ALOHA), may again become attractive as also proved by a number of technologies adopting it. The use of forward error correction (FEC) can improve its performance, yet a comprehensive analytical model including this aspect is still missing. In this paper, we provide a first attempt by deriving exact expressions for the packet loss rate and spectral efficiency of ALOHA with FEC, and extend the result also to time- and frequency-asynchronous ALOHA aided by FEC. We complement our study with extensive evaluations of the expressions for relevant cases of study, including an IoT system served by low-Earth orbit (LEO) satellites. Non-trivial outcomes show how time- and frequency-asynchronous ALOHA particularly benefit from the presence of FEC and become competitive with ALOHA.

Spectral Coexistence of QoS-Constrained and IoT Traffic in Satellite Systems.

The flourishing of Internet of Things (IoT) applications, characterized by vast transmitter populations and the sporadic transmission of small data units, demands innovative solutions for the sharing of the wireless medium. In this context, satellite connectivity is an important enabler for all scenarios in which terminals are under-served by terrestrial communications and are thus fundamental for providing worldwide coverage. In turn, the design of medium access policies that attain efficient use of the scarce spectrum and can cope with flexible yet unpredictable IoT traffic is of the utmost importance. Starting from these remarks, we investigate in this work the coexistence of a quality of service (QoS)-constrained service with IoT traffic in a shared spectrum as alternative to a more traditional orthogonal allocation among the two services, with an eye on satellite applications. Leaning on analytical tools, we provide achievable rate regions, assuming a slotted ALOHA access method for IoT terminals and accounting for practical aspects, such as the transmission of short packets. Interesting trends emerge, showcasing the benefit of an overlay allocation with respect to segregating the resources for the two services.

Number of consulting medical institutions and risk of polypharmacy in community-dwelling older people under a healthcare system with free access: a cross-sectional study in Japan.

BACKGROUND: Under the Japanese free access healthcare system, patients are allowed to consult multiple medical institutions (including clinics and hospitals for general or specialist consultation) without primary care referral. This potentially increases the risk of polypharmacy. We examined the association between the number of consulting medical institutions and polypharmacy under a healthcare system with free access. METHODS: Via a self-administered questionnaire, we identified people aged ≥65 years with ≥1 disease and ≥1 consulting medical institution in a Japanese city in 2016. The exposure of interest was the number of consulting medical institutions (1, 2, or ≥3) and the outcome was polypharmacy (use of ≥6 types of drugs). We performed a multivariate logistic regression analysis, adjusting for age, sex, household economy, and the number and type of comorbidities. To minimize confounding effects, we also performed propensity-score-matched analysis, categorizing patients into two groups: 1 and ≥2 consulting medical institutions. RESULTS: Of 993 eligible individuals (mean (standard deviation) age: 75.1 (6.5) years, men: 52.6%), 15.7% (156/993) showed polypharmacy. Proportions of polypharmacy were 9.7% (50/516), 16.6% (55/332), and 35.2% (51/145) for people who consulted 1, 2, and ≥3 medical institutions, respectively. Relative to people who consulted 1 medical institution, adjusted odds ratios (95% confidence intervals) for polypharmacy were 1.50 (0.94-2.37) and 3.34 (1.98-5.65) for those who consulted 2 and ≥3 medical institutions, respectively. In propensity score matching, of 516 and 477 patients who consulted 1 and ≥2 medical institutions, 307 pairs were generated. The proportion of polypharmacy was 10.8% (33/307) and 17.3% (53/307), respectively (P = 0.020). The odds ratio for polypharmacy (≥2 vs. 1 consulting medical institution) was 1.73 (95% confidence interval 1.09-2.76). CONCLUSIONS: Patients who consulted more medical institutions were more likely to show polypharmacy. The results could encourage physicians and pharmacists to collect medication information more actively and conduct appropriate medication reviews. Strengthening primary care is needed to address the polypharmacy issue, especially in countries with healthcare systems with free access.

Japan's health care system faces a perfect storm.

Although Japan has implemented a universal health care system that is universal in terms of free access to health care services, it is managed by fragmented and financially insecure insurance societies that have cumulative deficits even with government subsidies. In terms of insurance premiums, the system is regressive to low-income and unstable workers, and the social benefit scheme only captures 1.6% of this population. The Japanese government is continuously instituting new health care policies to reduce growing health care expenditures. Recent health care reforms may improve economic efficiency, but the changes remain limited to controlling access to health services and pricing measures.

Autonomous Power Decision for the Grant Free Access MUSA Scheme in the mMTC Scenario.

Non-orthogonal multiple access schemes with grant free access have been recently highlighted as a prominent solution to meet the stringent requirements of massive machine-type communications (mMTCs). In particular, the multi-user shared access (MUSA) scheme has shown great potential to grant free access to the available resources. For the sake of simplicity, MUSA is generally conducted with the successive interference cancellation (SIC) receiver, which offers a low decoding complexity. However, this family of receivers requires sufficiently diversified received user powers in order to ensure the best performance and avoid the error propagation phenomenon. The power allocation has been considered as a complicated issue especially for a decentralized decision with a minimum signaling overhead. In this paper, we propose a novel algorithm for an autonomous power decision with a minimal overhead based on a tight approximation of the bit error probability (BEP) while considering the error propagation phenomenon. We investigate the efficiency of multi-armed bandit (MAB) approaches for this problem in two different reward scenarios: (i) in Scenario 1, each user reward only informs about whether its own packet was successfully transmitted or not; (ii) in Scenario 2, each user reward may carry information about the other interfering user packets. The performances of the proposed algorithm and the MAB techniques are compared in terms of the successful transmission rate. The simulation results prove that the MAB algorithms show a better performance in the second scenario compared to the first one. However, in both scenarios, the proposed algorithm outperforms the MAB techniques with a lower complexity at user equipment.

Effects of milk replacer acidification and free-access feeding on early life feeding, oral, and lying behavior of dairy calves.

Acidification is a practical way of preserving the bacteriological quality of milk so that it can be fed to calves under free-access conditions. The objectives of this study were to evaluate how milk replacer acidification and free-access feeding affect dairy calf behavior during the first week of life. Sixteen Holstein male calves were purchased at birth and transported to the University of Guelph Kemptville Campus Dairy Education and Research Centre. Calves were randomly assigned to 1 of 4 milk feeding programs: (1) free-access (ad libitum) feeding of acidified milk replacer (22% crude protein and 17% fat, 150 g/L; FA); (2) restricted (6 L/d, 150 g/L) feeding of acidified milk replacer (RA); (3) free-access feeding of nonacidified milk replacer (FN); and (4) restricted feeding of nonacidified milk replacer (RN). Formic acid was used to acidify milk replacer to a target pH between 4.0 and 4.5. Video recordings of each calf at 1, 2, and 6 d were analyzed continuously over 24 h for all occurrences of each behavior in the ethogram. Feeding behavior observations were organized into sucking bouts, from which feeding behavior outcome variables were calculated. Calves consuming acidified milk replacer demonstrated more fragmented feeding patterns, characterized by more pauses within a sucking bout (FA, FN, RA, and RN calves = 12.4, 4.4, 13.7, and 11.9 pauses/bout, respectively) and longer sucking bout duration (FA, FN, RA, and RN calves = 8.8, 5.2, 9.3, and 8.1 min/bout, respectively), than calves fed nonacidified milk replacer. Restricted-fed calves tended to have longer sucking bouts and performed more within-bout sucks (FA, FN, RA, and RN calves = 10.7, 5.8, 13.5, and 14.1, respectively) and pauses than free-access calves. Acidification and free-access feeding did not affect lying duration. Calves assigned to the acidified feeding treatments tended to perform more grooming behavior than those fed nonacidified milk replacer (FA, FN, RA, and RN calves = 0.9, 0.5, 0.8, and 0.6 h/d, respectively). Free-access feeding did not affect grooming duration. The observed differences in feeding and grooming behavior suggest that acidification to a pH between 4.0 and 4.5 may have altered the palatability of milk replacer. Calves assigned to the acidified milk replacer feeding treatments did not, however, show avoidance toward this feedstuff during the first week of life.

Clinical trial on the effects of a free-access acidified milk replacer feeding program on the health and growth of dairy replacement heifers and veal calves.

The objectives of this study were to evaluate the effects of free-access acidified milk replacer feeding on the pre- and postweaning health of dairy and veal calves. Individually housed calves were systematically assigned at birth to 1 of 2 feeding programs: free-access feeding (ad libitum) of acidified milk replacer (ACD, n=249) or traditional restricted feeding (3L fed twice daily) of milk replacer (RES, n=249). Calves were fed milk replacer containing 24% crude protein and 18% fat. Acidified milk replacer was prepared to a target pH between 4.0 and 4.5 using formic acid. Calves were weaned off milk replacer at approximately 6wk of age. Weaning occurred over 5d, and during this weaning period, ACD calves had access to milk replacer for 12h/d and RES calves were offered only one feeding of milk replacer (3 L) daily. Calves were monitored daily for signs of disease. Fecal consistency scores were assigned each week from birth until weaning. A subset of calves was systematically selected for fecal sampling at 3 time points between 7 and 27d of age. Fecal samples were analyzed for enterotoxigenic Escherichia coli F5, Cryptosporidium parvum, rotavirus, and coronavirus. Hip width, hip height, body length, heart girth, and body weight were measured at birth and weaning. Postweaning body weight measurements were collected from the heifers at approximately 8mo of age. Postweaning body weight and carcass grading information was collected from the veal calves at slaughter once a live weight between 300 and 350kg had been achieved. The odds of ACD calves being treated for a preweaning disease event tended to be lower than that of the RES calves (1.2 vs. 5.2%, respectively). Preweaning mortality, postweaning disease treatment, and postweaning mortality did not differ between feeding treatments. The ACD feeding treatment supported greater preweaning average daily gain (0.59 vs. 0.43kg/d) and structural growth than RES feeding. Postweaning average daily gain and carcass characteristics were similar for ACD and RES calves. These results indicate that free-access acidified milk replacer feeding tended to support improved health, and greater body weight gain and structural growth during the preweaning period; these effects did not persist in the postweaning period. The growth advantage observed before weaning in the ACD calves likely disappeared due to the weaning methods used.

Reproductive dynamics shapes genomotype composition in an allopolyploid complex.

Hybrid complexes are composed of organisms with multiple combinations of parental genomes (genomotypes) that interconnect through nets of crosses. Although several such complexes are well established without speciation or extinction, mechanisms shaping their dynamics remain poorly understood. In this study, we quantified the reproductive success of the allopolyploid Iberian fish Squalius alburnoides in experimental free-access and directional crosses involving the most common genomotypes. Specifically, we analysed the paternity of the offspring produced when females had free access to male genomotypes and quantified variations in egg allocation, fertilization rate, and offspring survival among crosses involving each male genomotype. The composition of the offspring produced from free-access crosses varied significantly from that expected from random mating, suggesting that offspring production and viability are not independent of parental male genomotype. Moreover, directional crosses producing the genomotype most commonly found in wild populations appeared to be the most successful, with females laying more eggs, and fertilization rate and offspring survival being the highest. These results suggest that reproductive dynamics plays a relevant role in structuring the genomotype composition of populations and opens a path to future research on the ecology and evolutionary biology of allopolyploids and their multiplicity of possible evolutionary pathways.

FunRich proteomics software analysis, let the fun begin!

Protein MS analysis is the preferred method for unbiased protein identification. It is normally applied to a large number of both small-scale and high-throughput studies. However, user-friendly computational tools for protein analysis are still needed. In this issue, Mathivanan and colleagues (Proteomics 2015, 15, 2597-2601) report the development of FunRich software, an open-access software that facilitates the analysis of proteomics data, providing tools for functional enrichment and interaction network analysis of genes and proteins. FunRich is a reinterpretation of proteomic software, a standalone tool combining ease of use with customizable databases, free access, and graphical representations.

Cannabis self-administration in the human laboratory: a scoping review of ad libitum studies.

Cannabis self-administration studies may be helpful for identifying factors that influence cannabis consumption and subjective response to cannabis. Additionally, these paradigms could be useful for testing novel pharmacotherapies for cannabis use disorder. This scoping review aims to summarize the findings from existing ad libitum cannabis self-administration studies to determine what has been learned from these studies as well as their limitations. We examined studies that specifically examined cannabis smoking, focusing on subjective response and self-administration behavior (e.g., smoking topography). A systematic search was conducted using PubMed and Embase from inception to October 22, 2022. Our search strategy identified 26 studies (total N = 662, 79% male) that met our eligibility criteria. We found that tetrahydrocannabinol (THC) concentration significantly affected subjective response to cannabis in some but not all studies. In general, cannabis self-administration tended to be most intense at the beginning of the laboratory session and decreased in later parts of the session. There was limited data on cannabis self-administration in adults older than 55. Data on external validity and test-retest reliability were also limited. Addressing these limitations in future ad libitum cannabis self-administration studies could lead to more valid and generalizable paradigms, which in turn could be used to improve our understanding of cannabis use patterns and to help guide medication development for cannabis use disorder.

Optimal rate allocation in cluster-tree WSNs.

In this paper, we propose a solution to the problem of guaranteed time slot allocation in cluster-tree WSNs. Our design uses the so-called Network Utility Maximization (NUM) approach as far as we aim to provide a fair distribution of the available resources. From the point of view of implementation, we extend here the authors' proposed Coupled-Decompositions Method (CDM) in order to compute the NUM problem inside the cluster tree topology and we prove the optimality of this new extended version of the method. As a result, we obtain a distributed solution that reduces the total amount of signalling information in the network up to a factor of 500 with respect to the classical techniques, that is, primal and dual decomposition. This is possible because the CDM finds the optimal solution with a small number of iterations. Furthermore, when we compare our solution to the standard-proposed First Come First Serve (FCFS) policy, we realize that FCFS becomes pretty unfair as the traffic load in the network increases and thus, a fair allocation of resources can be considered whenever the price to pay in terms of signalling and computational complexity is controlled.

Recommending no further treatment: Gatekeeping work of generalists at a Japanese university hospital.

In medical decision-making, doctors have to take into consideration whether patients' expectations can be satisfied while appropriately allocating medical resources. This study explores how recommendations for no further treatment, or gate-closing recommendations, are resisted by patients and how doctors react to resistance in outpatient consultations at a university hospital in Japan. We show how the type of patient resistance shapes doctors' reactions. Problem-focused resistance problematizes the doctor's understanding of the patient's problem or the treatment itself without focusing on the gate-closing aspect of a recommendation, and is met with doctors' persuasion through diagnosis-based accounts. Provider-focused resistance focuses on the gate-closing aspect of a recommendation, and leads doctors to manage their dual roles as patient advocate and resource steward. Two subtypes of provider-focused resistance further shape this work differently. Unwillingness-focused resistance is met with persuasion mainly through institution-based accounts. Unavailability-focused resistance is met with a concession. Doctors systematically respond to patients' resistance in order to reach an agreement during decision-making. They take measures to reconcile their dual roles, and orient themselves toward the implicit rationale of gatekeeping, which has a moral nature.

Why this clinic now? A context-sensitive aspect of accounting for visits.

In presenting problems in medical consultations, patients face the task of justifying their visit to the doctor. Previous studies have shown that patients establish the legitimacy of their visit by characterizing their problem as "doctorable" and presenting themselves as reasonable patients (Halkowski, 2006; Heritage and Robinson, 2006). This study explores a context-sensitive aspect of this justification issue by analyzing patients' first visits to a department of general medicine under the Japanese "free access" system. Patients are shown to present their problem in a way that conveys its relevance to the particular medical setting: they characterize their problem as suitable for relatively high-level medical care or as not easily falling under other specialties. The patient's problem's relevance to the setting is treated as normative in that participants take measures to remedy the possible mismatch between the problem and the setting. The institutional arrangement of the Japanese free access system is "talked into being" as a relevant context for the consultations through the practices participants use to establish the legitimacy of their visits.

Free Marine Natural Products Databases for Biotechnology and Bioengineering.

Marine organisms and micro-organisms are a source of natural compounds with unique chemical features. These chemical properties are useful for the discovery of new functions and applications of marine natural products (MNPs). To extensively exploit the potential implementations of MNPs, they are gathered in chemical databases that allow their study and screening for applications of biotechnological interest. However, the classification of MNPs is currently poor in generic chemical databases. The present availability of free-access-focused MNP databases is scarce and the molecular diversity of these databases is still very low when compared to the paid-access ones. In this review paper, the current scenario of free-access MNP databases is presented as well as the hindrances involved in their development, mainly compound dereplication. Examples and opportunities for using freely accessible MNP databases in several important areas of biotechnology are also assessed. The scope of this paper is, as well, to notify the latent potential of these information sources for the discovery and development of new MNPs in biotechnology, and push future efforts to develop a public domain MNP database freely available for the scientific community.

Improving the mental health system for trauma victims in France.

France has a rich history of exposure to large-scale traumas such as wars, disasters and terrorist attacks, and psychiatric teams specialized in emergency interventions for mass trauma have been created across the territory. However, no public resources are dedicated for long-term interventions or for individual trauma cases. This letter describes how a government supported model of care has been created and implemented in 2019. A national centre for resources and resilience (CN2R) and 10 regional ambulatory services specializing in psychotraumatology were created with the aim of improving public mental health-care delivery while providing a comprehensive suite of services for trauma victims from the most immediate to longer-term considerations.

A free-access online key to identify Amazonian ferns.

There is urgent need for more data on species distributions in order to improve conservation planning. A crucial but challenging aspect of producing high-quality data is the correct identification of organisms. Traditional printed floras and dichotomous keys are difficult to use for someone not familiar with the technical jargon. In poorly known areas, such as Amazonia, they also become quickly outdated as new species are described or ranges extended. Recently, online tools have allowed developing dynamic, interactive, and accessible keys that make species identification possible for a broader public. In order to facilitate identifying plants collected in field inventories, we developed an internet-based free-access tool to identify Amazonian fern species. We focused on ferns, because they are easy to collect and their edaphic affinities are relatively well known, so they can be used as an indicator group for habitat mapping. Our key includes 302 terrestrial and aquatic entities mainly from lowland Amazonian forests. It is a free-access key, so the user can freely choose which morphological features to use and in which order to assess them. All taxa are richly illustrated, so specimens can be identified by a combination of character choices, visual comparison, and written descriptions. The identification tool was developed in Lucid 3.5 software and it is available at http://keyserver.lucidcentral.org:8080/sandbox/keys.jsp.

Wikipedia como medio de divulgación y comunicación científica: influencia en el campo educativo, investigativo y bibliotecológico-documental

Este artículo identifica elementos prácticos de aplicación de Wikipedia en sus contribuciones hacia la divulgación y comunicación científica aplicados a campos disciplinares distintos, tales como: (1) educativo (medio de transferencia en procesos de aprendizaje colaborativo, constructivismo, pensamiento crítico y transdisciplinariedad); (2) investigación científica (sistema estructurado de macrodatos y derivación de hallazgos a través de sus contenidos); y (3) bibliotecológico-documental (aplicación de métricas de la información, la derivación de lenguajes documentales controlados y no controlados, y formación de usuarios de la información). El desarrollo del artículo se basa en el uso de una metodología centrada en la fenomenología (desde la perspectiva de la ciencia), para lo cual se estudió un cuerpo de conocimiento sobre Wikipedia, relacionado con ámbitos educativos, de investigación científica y de la bibliotecología-documentación, a través de un análisis consistente, que condujo a la descripción e interpretación de experiencias vividas, reconociendo su significado e importancia como sistema de información con capacidad de influencia positiva y ética. Los resultados ofrecen elementos que fortalecen la credibilidad de Wikipedia como sistema de información, ya que ha sido paradigmáticamente cuestionada de forma negativa, por tanto, se propicia la identificación de aportaciones que justifican su valor como un sistema complejo, innovador y único en la socialización del conocimiento académico y científico, con amplia influencia en diversos campos formales del conocimiento, sin que se tenga aún un reconocimiento suficientemente sólido.

This article identifies practical elements of application of Wikipedia in its contributions towards the popularization and scientific communication applied to different disciplinary fields, such as: (1) educational (means of transfer in collaborative learning processes, constructivism, critical thinking and transdisciplinarity); (2) scientific research (structured system of big data and derivation of findings through its contents); and (3) library-documentary (application of information metrics, derivation of controlled and uncontrolled document languages, and training of information users). The development of the article is based on the use of a methodology focused on phenomenology (from the perspective of science), for which, a body of knowledge about Wikipedia was studied, related to educational, scientific research and library science fields. -documentation, through a consistent analysis, which led to the description and interpretation of lived experiences, recognizing its meaning and importance as an information system with the capacity for positive and ethical influence. The results offer elements that strengthen the credibility of Wikipedia as an information system, since it has been paradigmatically questioned in a negative way, therefore, the identification of contributions that justify its value as a complex, innovative and unique system in the socialization of the academic and scientific knowledge, with wide influence in various formal fields of knowledge, without yet having a sufficiently solid recognition.

Can free open access resources strengthen knowledge-based emerging public health priorities, policies and programs in Africa?

Tackling emerging epidemics and infectious diseases burden in Africa requires increasing unrestricted open access and free use or reuse of regional and global policies reforms as well as timely communication capabilities and strategies. Promoting, scaling up data and information sharing between African researchers and international partners are of vital importance in accelerating open access at no cost. Free Open Access (FOA) health data and information acceptability, uptake tactics and sustainable mechanisms are urgently needed. These are critical in establishing real time and effective knowledge or evidence-based translation, proven and validated approaches, strategies and tools to strengthen and revamp health systems.  As such, early and timely access to needed emerging public health information is meant to be instrumental and valuable for policy-makers, implementers, care providers, researchers, health-related institutions and stakeholders including populations when guiding health financing, and planning contextual programs.

Group space allowance has little effect on sow health, productivity, or welfare in a free-access stall system.

Free-access stalls allow sows to choose the protection of a stall or use of a shared group space. This study investigated the effect of group space width, 0.91 (SS), 2.13 (IS), and 3.05 (LS) m, on the health, production, behavior, and welfare of gestating sows. Nine replications of 21 (N = 189) gestating sows were used. At gestational d 35.4 ± 2.3, the pregnant sows were distributed into 3 pens of 7 sows, where they remained until 104.6 ± 3.5 d. Each treatment pen had 7 free-access stalls and a group space that together provided 1.93 (SS), 2.68 (IS), or 3.24 (LS) m(2)/sow. Baseline measurements were obtained before mixing. Back fat depth, BW, BCS, and lameness were measured monthly, and skin lesions were scored weekly. Blood was collected monthly for hematological, immunological, and cortisol analyses. Sow behavior was video recorded continuously during the initial 4 d of treatment and 24 h every other week thereafter. Behavior was analyzed for location, posture, pen investigation, social contact, and aggression. Skin response to the mitogen concanavalin A (Con A) was tested at mean gestational d 106. Litter characteristics including size and weight were collected at birth and weaning. The data were analyzed using a mixed model. Multiple comparisons were adjusted with the Tukey-Kramer and Bejamini-Hochberg methods. Group space allowance had no effect on any measure of sow health, physiology, or production (P ≥ 0.10). Sows in the SS, IS, and LS pens spent 77.88% ± 3.88%, 66.02% ± 3.87%, and 63.64% ± 3.91%, respectively, of their time in the free-access stalls (P = 0.12). However, SS sows used the group space less than IS and LS sows (P = 0.01). Overall, pen investigatory behavior was not affected by group space allowance (P = 0.91). Sows in the LS pens spent more time in a social group than SS sows (P = 0.02), whereas sows in IS pens were intermediate to, but not different from, the other treatments (P ≥ 0.10). The size of the social groups was also affected by the group space allowance (P = 0.03), with SS sows forming smaller groups than LS sows; again, IS sows were intermediate to, but not different from, the other treatments. Although the group space allowance had no measurable impact on the health, physiology, or productivity of the sows, the lower group space use and social contact of the SS sows reduced the behavioral diversity benefits of group housing and may indicate an avoidance of social stressors or a lack of physical comfort in the smallest pens.

[Socio-demographic characteristics and health status of patients at a free-of-charge outpatient clinic in Paris]. / Analyse du profil socio-démographique et médical des patients de 5 permanences d'accès aux soins de santé (PASS) parisiennes.

PURPOSE: In the context of the French National Health Service, a free access to healthcare facilities (the PASS: "permanence d'accès aux soins de santé") has been implanted in 2000 for patients without health insurance or those dealing with financial hardship. There is few data about socio-demographic characteristics of the patients using these services. The objective of this study was to provide descriptive data about socio-demographic characteristics and motivation of those patients who use these clinics. METHODS: This descriptive cross-sectional study was conducted between April an May 2008, in 5 PASS clinics from academic tertiary hospitals in Paris. Descriptive data on patient were collected by general practitioners at the end of their consultations. RESULTS: This study included 581 patients. The mean age was 42 years, and 65% of patients were males. Only 50.9% declared a salary income and 38.5% had a health insurance. Half of the patients were homeless, and 80% were migrants. The main reasons to visit these health facilities were direct access (no appointment needed), being in financial difficulty and having a medical record in the same hospital. Half of the patients had one chronic disease at least, while only a third of them saw regularly a physician. A total of 834 diseases were found among the 581 patients, including 411 chronic diseases, and 17% of the patients had a psychologic or a psychiatric disorder. Prognosis was divided in three grades: good, low and poor. Almost a half of the patients were considered by the doctor as having a low or a poor prognosis if they would not receive a therapy. CONCLUSIONS: The findings of this study suggest that the PASS carry out their mission: most of the patients frequenting these facilities live under poor conditions and are in poor health status compared to the patients having access to conventional outpatient services.