Analysing the Complexity of Functional Programs: Higher-Order Meets First-Order

International audienceWe show how the complexity of higher-order functional programs can be analysed automatically by applying program transformations to a defunctionalized versions of them, and feeding the result to existing tools for the complexity analysis of first-order term rewrite systems. This is done while carefully analysing complexity preservation and reflection of the employed transformations such that the complexity of the obtained term rewrite system reflects on the complexity of the initial program. Further, we describe suitable strategies for the application of the studied transformations and provide ample experimental data for assessing the viability of our method

Doing Syringe Exchange: Organizational Transformation and Volunteer Commitment

The authors examine the organizational transformation of Prevention Point, the San Francisco-based syringe exchange program. Their purposes are to explore the processes of organizational change, focus on the impact of formalization on members and organizational goals, and contextualize these in light of belonging to an underground organization. They highlight the volunteers’ motivation and commitment, and their responses to the organizational changes. Drawing on qualitative interviews with 56 service providers, conducted from 1993 to 1995, the authors document the changes in the organization and the members’ perceptions of it as it moved from an illegal, deviant group to a socially sanctioned service organization. This transition is shown to have ultimately undermined much of the basis for volunteer commitment, reinforcing the shift in responsibility from the membership to a new management structure. These findings have implications for the larger problem of maintaining volunteer engagement in volunteer work.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Hepatitis Vaccination of Men Who Have Sex with Men at Gay Pride Events

Prevention researchers have advocated primary prevention such as vaccination in alternative venues. However, there have been major questions about both the attendance of, and the ability to, vaccinate high-risk individuals in such settings. The current study seeks to assess the feasibility of vaccinating high-risk men who have sex with men (MSM) at Gay Pride events. The research questions are: Do gay men who are sampled at Gay Pride events engage in more or less risky behavior than gay men sampled at other venues? Do the gay men who receive hepatitis vaccinations at Gay Pride engage in more or less risky behavior than gay men at Gay Pride who do not receive hepatitis vaccination? Of the 3689 MSM that completed the Field Risk Assessment (FRA), 1095/3689 = 29.68% were recruited at either the 2006 or 2007 Long Beach, California Gay Pride events. The remaining, 2594/3689 = 70.32% were recruited at Long Beach gay bars, gay community organizations and institutions, and through street recruitment in various gay enclaves in the Long Beach area. Logistic regression analysis yielded eight factors that were associated with non-attendance of Gay Pride: Age, had sex while high in the last 12 months, had unprotected anal intercourse (UAI) in the last 12 months, had sex for drugs/money in the last 12 months, been diagnosed with a sexually transmitted infection (STI) in the last 12 months, used nitrites (poppers) in the last 12 months, and used methamphetamine in the last 12 months. Identifying as White, Asian, or African American compared to Hispanic was also associated with non-attendance. Bivariate analysis indicated that, of the MSM sampled at Gay Pride, 280/1095 = 25.57% received a hepatitis vaccination there. The MSM sampled at Gay Pride who reported engaging in UAI or having used any stimulant (cocaine, crack-cocaine, or methamphetamine) in the last 12 months were more likely to receive hepatitis vaccination on-site. The results provide evidence for the viability of successfully vaccinating high-risk MSM at Gay Pride events. However, it is vital that no-cost vaccinations are also funded in other community settings such as STI clinics, drug treatment programs, prisons, universities, and other community resource centers in order to reach those additional high-risk MSM who do not attend Gay Pride

Dynamic calibration of order flow models with generative adversarial networks

Classical models for order flow dynamics based on point processes, such as Poisson or Hawkes processes, have been studied intensively. Often, several days of limit border book (LOB) data is used to calibrate such models, thereby averaging over different dynamics - such as intraday effects or different trading volumes. This work uses generative adversarial networks (GANs) to learn the distribution of calibrations – obtained by many calibrations based on short time frames. The trained GAN can then be used to generate synthetic, realistic calibrations based on external conditions such as time of the day or volatility. Results show that GANs easily reproduce patterns of the order arrival intensities and can fit the distribution well without heavy parameter tuning. The synthetic calibrations can then be used to simulate order streams which contain new dynamics such as temporary drifts, different volatility regimes, but also intra-day patterns such as the commonly observed U-shape that reflects stylized behaviour around open and close of market hours.</p

Automatic Train Coupling: Challenges and Key Enablers

Railways are the safest and most energy efficient means of land transportation. Unfortunately, they are less attractive than other transportation means due to the relatively high ticket prices and unreliable travel times. Both are a consequence of high running and maintenance costs and the inefficient usage of the railway infrastructure. In this article, we introduce new railway applications that increase railway safety and track-use. This will accordingly decrease running costs. For instance, automatic train coupling will enable trains to automatically couple when they use the same track section and to automatically separate when they are required to use different tracks. This will enhance energy efficiency, track use, and running costs while maintaining the safety requirements. To enable such an application, we introduce an ultra-reliable and low-latency (URLLC) millimeter-wave (mmWave) wireless communication system, namely the SBDist system, which provides direct communication and ranging between trains. We show from measurements data and simulations that the SBDist system achieves round-trip latency values below 50µs and that the packet error rate (PER) values are enhanced by using circularly polarized antennas and applying a novel redundancy scheme

Automatic Train Coupling: Challenges and Key Enablers

Railways are the safest and most energy efficient means of land transportation. Unfortunately, they are less attractive than other transportation means due to the relatively high ticket prices and unreliable travel times. Both are a consequence of high running and maintenance costs and the inefficient usage of the railway infrastructure. In this article, we introduce new railway applications that increase railway safety and track-use. This will accordingly decrease running costs. For instance, automatic train coupling will enable trains to automatically couple when they use the same track section and to automatically separate when they are required to use different tracks. This will enhance energy efficiency, track use, and running costs while maintaining the safety requirements. To enable such an application, we introduce an ultra-reliable and low-latency (URLLC) millimeter-wave (mmWave) wireless communication system, namely the SBDist system, which provides direct communication and ranging between trains. We show from measurements data and simulations that the SBDist system achieves round-trip latency values below 50µs and that the packet error rate (PER) values are enhanced by using circularly polarized antennas and applying a novel redundancy scheme

Healthcare professionals’ perceived barriers in providing palliative care in primary care and nursing homes: a survey study

Background: Palliative care in primary care and nursing home settings is becoming increasingly important. A multidimensional palliative care approach, provided by a multiprofessional team, is essential to meeting patients’ and relatives’ values, wishes, and needs. Factors that hamper the provision of palliative care in this context have not yet been fully explored. Objectives: To identify the barriers to providing palliative care for patients at home or in nursing homes as perceived by healthcare professionals. Design: Cross-sectional survey study. Methods: A convenience sample of nurses, doctors, chaplains, and rehabilitation therapists working in primary care and at nursing homes in the Netherlands is used. The primary outcome is barriers, defined as statements with ⩾20% negative response. The survey contained 56 statements on palliative reasoning, communication, and multiprofessional collaboration. Data were analyzed using descriptive statistics. Results: In total, 249 healthcare professionals completed the survey (66% completion rate). The main barriers identified in the provision of palliative care were the use of measurement tools (43%), consultation of an expert (31%), estimation of life expectancy (29%), and documentation in the electronic health record (21% and 37%). In primary care, mainly organizational barriers were identified, whereas in nursing homes, most barriers were related to care content. Chaplains and rehabilitation therapists perceived the most barriers. Conclusion: In primary care and nursing homes, there are barriers to the provision of palliative care. The provision of palliative care depends on the identification of patients with palliative care needs and is influenced by individual healthcare professionals, possibilities for consultation, and the electronic health record. An unambiguous and systematic approach within the multiprofessional team is needed, which should be patient-driven and tailored to the setting

Understanding HIV Risks of Chronic Drug-Using Men Who Have Sex with Men

Focus groups and individual structured interviews were conducted in six cities with 98 predominantly street-recruited men who had a recent history of smoking crack or injecting drugs and who reported having had sex with other men (MSM) in the past year. Twenty-six focus groups explored the cultural and social context of participant\u27s drug use and sexual activity and addressed outreach and HIV prevention issues pertinent to this population. Narrative summaries developed from verbatim focus group transcripts identified seven themes: (a) sexual orientation and gender identity; (b) interactions within and between MSM networks; (c) drug use, sexual activity and personal relationships; (d) HIV transmission bridges; (e) preferred HIV information sources; (f) HIV knowledge, prevention practices and risk behaviours; and (g) availability of HIV and drug-related services. Of the 98 MSM drug users, 42% identified publicly as gay or homosexual; 35% identified publicly, but only 21% privately, as heterosexual. A total of 51% had one or more female sex partners in the past year. There was a high frequency of unprotected sex in conjunction with drug use and a distinct preference for having sex when high. For most participants, drug use rather than sexual orientation formed the core of personal identity. Participants reported associating primarily with other drug users, usually MSM, and had limited contact with people who did not use drugs and the mainstream gay community. Participants\u27 sexual and drug-injecting activities were judged to be a bridge for transmission of HIV to both people who used drugs and those who did not

Understanding HIV Risks of Chronic Drug-Using Men Who Have Sex with Men

Focus groups and individual structured interviews were conducted in six cities with 98 predominantly street-recruited men who had a recent history of smoking crack or injecting drugs and who reported having had sex with other men (MSM) in the past year. Twenty-six focus groups explored the cultural and social context of participant\u27s drug use and sexual activity and addressed outreach and HIV prevention issues pertinent to this population. Narrative summaries developed from verbatim focus group transcripts identified seven themes: (a) sexual orientation and gender identity; (b) interactions within and between MSM networks; (c) drug use, sexual activity and personal relationships; (d) HIV transmission bridges; (e) preferred HIV information sources; (f) HIV knowledge, prevention practices and risk behaviours; and (g) availability of HIV and drug-related services. Of the 98 MSM drug users, 42% identified publicly as gay or homosexual; 35% identified publicly, but only 21% privately, as heterosexual. A total of 51% had one or more female sex partners in the past year. There was a high frequency of unprotected sex in conjunction with drug use and a distinct preference for having sex when high. For most participants, drug use rather than sexual orientation formed the core of personal identity. Participants reported associating primarily with other drug users, usually MSM, and had limited contact with people who did not use drugs and the mainstream gay community. Participants\u27 sexual and drug-injecting activities were judged to be a bridge for transmission of HIV to both people who used drugs and those who did not