Fisher-information condition for enhanced signal detection via stochastic resonance

Various situations where a signal is enhanced by noise through stochastic resonance are now known. This paper contributes to determining general conditions under which improvement by noise can be a priori decided as feasible or not. We focus on the detection of a known signal in additive white noise. Under the assumptions of a weak signal and a sufficiently large sample size, it is proved, with an inequality based on the Fisher information, that improvement by adding noise is never possible, generically, in these conditions. However, under less restrictive conditions, an example of signal detection is shown with favorable action of adding noise.Fabing Duan, François Chapeau-Blondeau, Derek Abbot

Sustainable development of smallholder crop-livestock farming in developing countries

Meeting the growing demand for animal-sourced food, prompted by population growth and increases in average per-capita income in low-income countries, is a major challenge. Yet, it also presents significant potential for agricultural growth, economic development, and reduction of poverty in rural areas. The main constraints to livestock producers taking advantage of growing markets include; lack of forage and feed gaps, communal land tenure, limited access to land and water resources, weak institutions, poor infrastructure and environmental degradation. To improve rural livelihood and food security in smallholder crop-livestock farming systems, concurrent work is required to address issues regarding efficiency of production, risk within systems and development of whole value chain systems. This paper provides a review of several forage basedstudies in tropical and non-tropical dry areas of the developing countries. A central tenet of this paper is that forages have an essential role in agricultural productivity, environmental sustainability and livestock nutrition in smallholder mixed farming systems

Rethinking energy security and services in practice: national vulnerability and three energy pathways in Tajikistan

To help answer questions about availability, accessibility, sustainability and other dimensions of energy security, the vulnerability approach concentrates the attention of policymakers on the assessment of risks associated with natural, technical, political and economic factors. This understanding, combined with a focus on energy services (e.g. lighting, heating, telecommunications, mobility, etc.) helps to prioritize actions to achieve the goal of energy security. This paper conceptualizes energy security as low vulnerability of vital energy systems and sustained provision of modern energy services. Taking Tajikistan as a case, this paper highlights key vulnerabilities including neglect of environmental conditions, insufficient energy production capacity, unreliable and expensive energy imports, dwindling power infrastructure causing technical and economic losses, inadequate transparency in the power sector, lack of regional cooperation in energy and water resources sharing, and inadequate financial resources to address these challenges. Three major proposals presented by the World Bank, the United Nations Development Program, and the Government of Tajikistan to achieve energy security in Tajikistan are evaluated. Specifically, they lack a focus on energy services and therefore overlook people's socio-cultural context and appropriate energy needs. This paper highlights energy services as critical to people’s wellbeing and socio-economic development

Seriously Injured Urban Black Men’s Perceptions of Clinical Research Participation

Purpose: Black men are uniquely vulnerable in American society and our health care system: they bear a disproportionate burden of injury, yet are underrepresented in clinical research. This study aimed to explore the reasons why urban Black men with serious injuries chose to participate in clinical research and their concerns about research participation. Methods: This qualitative study was conducted within the context of a larger study focused on psychological effects of serious injury in urban Black men; 83 Black men with serious injuries were recruited while hospitalized in an urban trauma center. Informed consent was obtained. Semi-structured interviews were conducted in participants’ homes three months after discharge from the hospital and were audiotaped, transcribed, and de-identified. Thematic content analysis was used to identify themes about perceptions of participating in clinical research. Results: The mean age of our sample was 38.2 years, and the mean injury severity score was 10.7 (SD 9.6). The majority (53.2 %) of injuries was due to interpersonal violence, and 47 % were due to unintentional mechanisms. Eight reasons for research participation emerged from the data: human connection, altruism/community, self-improvement, compensation, gaining knowledge, curiosity/interest, low risk, and reciprocity. Conclusions: A major finding was that injured urban Black men participated in clinical research for the opportunity for human and therapeutic connection. Despite some expressions of mistrust, participants were willing to participate for altruistic reasons rooted in community priorities, and as part of their recovery process post-injury

Seriously Injured Urban Black Men’s Perceptions of Clinical Research Participation

Purpose: Black men are uniquely vulnerable in American society and our health care system: they bear a disproportionate burden of injury, yet are underrepresented in clinical research. This study aimed to explore the reasons why urban Black men with serious injuries chose to participate in clinical research and their concerns about research participation. Methods: This qualitative study was conducted within the context of a larger study focused on psychological effects of serious injury in urban Black men; 83 Black men with serious injuries were recruited while hospitalized in an urban trauma center. Informed consent was obtained. Semi-structured interviews were conducted in participants’ homes three months after discharge from the hospital and were audiotaped, transcribed, and de-identified. Thematic content analysis was used to identify themes about perceptions of participating in clinical research. Results: The mean age of our sample was 38.2 years, and the mean injury severity score was 10.7 (SD 9.6). The majority (53.2 %) of injuries was due to interpersonal violence, and 47 % were due to unintentional mechanisms. Eight reasons for research participation emerged from the data: human connection, altruism/community, self-improvement, compensation, gaining knowledge, curiosity/interest, low risk, and reciprocity. Conclusions: A major finding was that injured urban Black men participated in clinical research for the opportunity for human and therapeutic connection. Despite some expressions of mistrust, participants were willing to participate for altruistic reasons rooted in community priorities, and as part of their recovery process post-injury

Historical Scientific Racism and Psychiatric Publications: A Necessary International Anti-racist Code of Ethics

Ethical aspects of publishing in scientific journals are an important issue addressed since the late 1970s by the International Committee of Medical Journal Editors (1978). Today, medical journals also benefit from other international organizations’ recommendations such as the Committee on Publication Ethics, World Association of Medical Editors, and World Health Organization (WHO). These international best practices guidelines cover various ethical issues related to integrity in research, authorship, conflicts of interest, and so on

Effect of Acute Exposure to Hypergravity (Gx vs. Gz) on Dynamic Cerebral Autoregulation

We examined the effects of 30 min of exposure to either +3G(sub x) or +3G(sub z) centrifugation on cerebrovascular responses to 800 head-up tilt (HUT) in 14 healthy individuals. Both before and after +3G(sub x) or +3G(sub z) centrifugation, eye-level blood pressure (BP(sub eye)), end tidal CO2 (P(sub ET)CO2), mean cerebral flow velocity (CFV) in the middle cerebral artery (trans cranial Doppler ultrasound), cerebral vascular resistance (CVR) and dynamic cerebral autoregulatory gain (GAIN) were measured with subjects in the supine position and during subsequent 800 HUT for 30 min. Mean BP(sub eye) decreased with HUT in both the G(sub x) (n= 7) and G(sub z) (n=7) groups (P less than 0.00l), with the decrease being greater after centrifugation only in the G(sub z) group (P less than 0.05). P(sub ET)CO2 also decreased with HUT in both groups (P less than 0.0l), but the absolute level of decrease was unaffected by centrifugation. CFV decreased during HUT more significantly after than before centrifugation in both groups (P less than 0.02). However, these greater decreases were not associated with greater increases in CVR. In the supine position after compared to before centrifugation, GAIN increased in both groups (P less than 0.05, suggesting an autoregulatory deficit), with the change being correlated to a measure of otolith function (the linear vestibulo-ocular reflex) in the G(sub x) group (R=0.76, P less than 0.05) but not in the G(sub z) group (R=0.24, P=0.60). However, GAIN was subsequently restored to pre-centrifugation levels during post-centrifugation HUT (i.e., as BP(sub eye) decreased), suggesting that both types of centrifugation resulted in a leftward shift of the cerebral autoregulation curve. We speculate that this leftward shift may have been due to vestibular activation (especially during +G(sub x)) or potentially to an adaptation to reduced cerebral perfusion pressure during +G(sub z)

Youth\u27s Strategies for Staying Safe and Coping With the Stress of Living in Violent Communities.

Youth living in urban environments of pervasive violence are exposed to a variety of violence-related stressors. This qualitative descriptive study sought to ascertain how community-dwelling youth perceived exposure to violence and how these youth identified and used available resources. The intent of this community-based participatory research study was to help inform the design of a youth violence prevention center intervention. Semi-structured interviews were conducted with a purposive sample of 18 youth ages 10-16. Youth reported high levels of exposure to neighborhood violence. A theme of identifying and navigating safe and unsafe places emerged. Other stressors were more proximal and included interpersonal issues and conflicts. Youth used neighborhood and individual resources to cope with stressors. Youth maintained a high level of vigilance and developed clear strategies to safely navigate violent neighborhoods. Implications for youth due to the constant vigilance and exquisite sensitivity to stressors of chronic neighborhood violence are discussed

An excess power statistic for detection of burst sources of gravitational radiation

We examine the properties of an excess power method to detect gravitational waves in interferometric detector data. This method is designed to detect short-duration (< 0.5 s) burst signals of unknown waveform, such as those from supernovae or black hole mergers. If only the bursts' duration and frequency band are known, the method is an optimal detection strategy in both Bayesian and frequentist senses. It consists of summing the data power over the known time interval and frequency band of the burst. If the detector noise is stationary and Gaussian, this sum is distributed as a chi-squared (non-central chi-squared) deviate in the absence (presence) of a signal. One can use these distributions to compute frequentist detection thresholds for the measured power. We derive the method from Bayesian analyses and show how to compute Bayesian thresholds. More generically, when only upper and/or lower bounds on the bursts duration and frequency band are known, one must search for excess power in all concordant durations and bands. Two search schemes are presented and their computational efficiencies are compared. We find that given reasonable constraints on the effective duration and bandwidth of signals, the excess power search can be performed on a single workstation. Furthermore, the method can be almost as efficient as matched filtering when a large template bank is required. Finally, we derive generalizations of the method to a network of several interferometers under the assumption of Gaussian noise.Comment: 22 pages, 6 figure