The motion of whips and chains

We study the motion of an inextensible string (a whip) fixed at one point in the absence of gravity, satisfying the equations $$\eta_{tt} = \partial_s(\sigma \eta_s), \qquad \sigma_{ss}-\lvert \eta_{ss}\rvert^2 = -\lvert \eta_{st}\rvert^2, \qquad \lvert \eta_s\rvert^2 \equiv 1$$ with boundary conditions $\eta(t,1)=0$ and $\sigma(t,0)=0$. We prove local existence and uniqueness in the space defined by the weighted Sobolev energy $$\sum_{\ell=0}^m \int_0^1 s^{\ell} \lvert \partial_s^{\ell}\eta_t\rvert^2 \, ds + \int_0^1 s^{\ell+1} \lvert \partial_s^{\ell+1}\eta\rvert^2 \, ds,$$ when $m\ge 3$. In addition we show persistence of smooth solutions as long as the energy for $m=3$ remains bounded. We do this via the method of lines, approximating with a discrete system of coupled pendula (a chain) for which the same estimates hold.Comment: 47 pages, 8 figure

Drinking in social groups. Does 'groupdrink' provide safety in numbers when deciding about risk?

AimsTo investigate the impact of alcohol consumption on risk decisions taken both individually and while part of a four- to six-person ad-hoc group.DesignA 2 (alcohol: consuming versus not consuming alcohol) x 2 (decision: individual, group) mixed-model design; decision was a repeated measure. The dependent variable was risk preference, measured using choice dilemmas.SettingOpportunity sampling in campus bars and a music event at a campus-based university in the United Kingdom.ParticipantsA total of 101 individuals were recruited from groups of four to six people who either were or were not consuming alcohol.MeasurementsParticipants privately opted for a level of risk in response to a choice dilemma and then, as a group, responded to a second choice dilemma. The choice dilemmas asked participants the level of accident risk at which they would recommend someone could drive while intoxicated.FindingsFive three-level multi-level models were specified in the software program HLM 7. Decisions made in groups were less risky than those made individually (B = -0.73, P < 0.001). Individual alcohol consumers opted for higher risk than non-consumers (B = 1.27, P = 0.025). A significant alcohol?×?decision interaction (B = -2.79, P = 0.001) showed that individual consumers privately opted for higher risk than non-consumers, whereas risk judgements made in groups of either consumers or non-consumers were lower. Decisions made by groups of consumers were less risky than those made by groups of non-consumers (B = 1.23, P < 0.001).ConclusionsModerate alcohol consumption appears to produce a propensity among individuals towards increased risk-taking in deciding to drive while intoxicated, which can be mitigated by group monitoring processes within small (four- to six-person) groups

Synchronization of stochastic genetic oscillator networks with time delays and Markovian jumping parameters

The official published version of the article can be found at the link below.Genetic oscillator networks (GONs) are inherently coupled complex systems where the nodes indicate the biochemicals and the couplings represent the biochemical interactions. This paper is concerned with the synchronization problem of a general class of stochastic GONs with time delays and Markovian jumping parameters, where the GONs are subject to both the stochastic disturbances and the Markovian parameter switching. The regulatory functions of the addressed GONs are described by the sector-like nonlinear functions. By applying up-to-date ‘delay-fractioning’ approach for achieving delay-dependent conditions, we construct novel matrix functional to derive the synchronization criteria for the GONs that are formulated in terms of linear matrix inequalities (LMIs). Note that LMIs are easily solvable by the Matlab toolbox. A simulation example is used to demonstrate the synchronization phenomena within biological organisms of a given GON and therefore shows the applicability of the obtained results.This work was supported in part by the Biotechnology and Biological Sciences Research Council (BBSRC) of the UK under Grants BB/C506264/1 and 100/EGM17735, the Royal Society of the UK, the National Natural Science Foundation of China under Grant 60804028, the Teaching and Research Fund for Excellent Young Teachers at Southeast University of China, the International Science and Technology Cooperation Project of China under Grant 2009DFA32050, and the Alexander von Humboldt Foundation of Germany

Neural mechanisms of economic commitment in the human medial prefrontal cortex

Neurobiologists have studied decisions by offering successive, independent choices between goods or gambles. However, choices often have lasting consequences, as when investing in a house or choosing a partner. Here, humans decided whether to commit (by acceptance or rejection) to prospects that provided sustained financial return. BOLD signals in the rostral medial prefrontal cortex (rmPFC) encoded stimulus value only when acceptance or rejection was deferred into the future, suggesting a role in integrating value signals over time. By contrast, the dorsal anterior cingulate cortex (dACC) encoded stimulus value only when participants rejected (or deferred accepting) a prospect. dACC BOLD signals reflected two decision biases–to defer commitments to later, and to weight potential losses more heavily than gains–that (paradoxically) maximised reward in this task. These findings offer fresh insights into the pressures that shape economic decisions, and the computation of value in the medial prefrontal cortex. - See more at: http://elifesciences.org/content/3/e03701#sthash.rpmo51q5.dpu

Two treatments, one disease: childhood malaria management in Tanga, Tanzania

<p>Abstract</p> <p>Background</p> <p>In the Tanga District of coastal Tanzania, malaria is one of the primary causes of mortality for children under the age of five. While some children are treated with malaria medications in biomedical facilities, as the World Health Organization recommends, others receive home-care or treatment from traditional healers. Recognition of malaria is difficult because symptoms can range from fever with uncomplicated malaria to convulsions with severe malaria. This study explores why caregivers in the Tanga District of Tanzania pursue particular courses of action to deal with malaria in their children.</p> <p>Methods</p> <p>Qualitative data were collected through interviews with three samples: female caregivers of children under five (N = 61), medical practitioners (N = 28), and traditional healers (N = 18) in urban, peri-urban, and rural areas. The female caregiver sample is intentionally stratified to reflect the greater population of the Tanga District in level of education, marital status, gender of household head, religion, and tribal group affiliation. Qualitative data were counted, coded and analysed using NVivo7 software.</p> <p>Results</p> <p>Results indicate that a variety of factors influence treatment choice, including socio-cultural beliefs about malaria symptoms, associations with spiritual affliction requiring traditional healing, knowledge of malaria, and fear of certain anti-malaria treatment procedures. Most notably, some caregivers identified convulsions as a spiritual condition, unrelated to malaria. While nearly all caregivers reported attending biomedical facilities to treat children with fever (N = 60/61), many caregivers stated that convulsions are best treated by traditional healers (N = 26/61). Qualitative interviews with medical practitioners and traditional healers confirmed this belief.</p> <p>Conclusion</p> <p>Results offer insight into current trends in malaria management and have implications in healthcare policy, educational campaigns, and the importance of integrating traditional and biomedical approaches.</p

The association of exposure, risk, and resiliency factors with PTSD among Jews and Arabs exposed to repeated acts of terrorism in Israel

Israel has faced ongoing terrorism since the beginning of the Al Aqsa Intifada in September 2000. The authors examined risk and resiliency factors associated with posttraumatic stress disorder (PTSD) among 1,117 Jews and 394 Arab adult citizens of Israel during August and September 2004 through telephone interviews. Probable PTSD was found among 6.6% of Jews and 18.0% of Arabs. Predictors of probable PTSD in a multivariate model for Jews were refusal to report income, being traditionally religious, economic and psychosocial resource loss, greater traumatic growth, and lower social support. For Arabs, predictors were low education and economic resource loss among those exposed to terrorism. Findings for only those directly exposed to terrorism were similar to those for the overall national sample.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58032/1/20307_ftp.pd

DHA supplementation during pregnancy does not reduce BMI or body fat mass in children: follow-up of the DHA to Optimize Mother Infant Outcome randomized controlled trial

First published March 30, 2016The omega-3 (n-3) long-chain polyunsaturated fatty acid (LCPUFA) docosahexaenoic acid (DHA) has proven effective at reducing fat storage in animal studies. However, a systematic review of human trials showed a lack of quality data to support or refute this hypothesis.We sought to determine whether maternal DHA supplementation during the second half of pregnancy results in a lower body mass index (BMI) and percentage of body fat in children.We conducted a follow-up at 3 and 5 y of age of children who were born to mothers enrolled in the DOMInO (DHA to Optimize Mother Infant Outcome) double-blind, randomized controlled trial, in which women with a singleton pregnancy were provided with DHA-rich fish-oil capsules (800 mg DHA/d) or vegetable-oil capsules (control group) in the second half of pregnancy. Primary outcomes were the BMIzscore and percentage of body fat at 3 and 5 y of age. Potential interactions between prenatal DHA and the peroxisome proliferator-activated receptor-γ (PPARγ) genotype as a measure of the genetic predisposition to obesity were investigated.A total of 1614 children were eligible for the follow-up. Parent or caregiver consent was obtained for 1531 children (95%), and these children were included in the analysis. BMIzscores and percentages of body fat of children in the DHA group did not differ from those of children in the control group at either 3 y of age [BMIzscore adjusted mean difference: 0.03 (95% CI: -0.07, 0.13;P= 0.61); percentage of body fat adjusted mean difference: -0.26 (95% CI: -0.99, 0.46;P= 0.47)] or 5 y of age [BMIzscore adjusted mean difference: 0.02 (95% CI: -0.08, 0.12;P= 0.66); percentage of body fat adjusted mean difference: 0.11 (95% CI: -0.60, 0.82;P= 0.75)]. No treatment effects were modified by thePPARγgenotype of the child.Independent of a genetic predisposition to obesity, maternal intake of DHA-rich fish oil during the second half of pregnancy does not affect the growth or body composition of children at 3 or 5 y of age. This trial was registered atwww.anzctr.org.auas ACTRN1260500056906 and ACTRN12611001127998.Beverly S Muhlhausler, Lisa N Yelland, Robyn McDermott, Linda Tapsell, Andrew McPhee, Robert A Gibson, and Maria Makride

Ask Me! Self-reported features of adolescents experiencing neglect or emotional maltreatment: a rapid systematic review

Neglect is often overlooked in adolescence, due in part to assumptions about autonomy and misinterpretation of behaviors being part of normal adolescent development. Emotional maltreatment (abuse or neglect) has a damaging effect throughout the lifespan, but is rarely recognized amongst adolescents. Our review aims to identify features that adolescents experiencing neglect and/ or emotional maltreatment report. METHOD: A rapid review methodology searched 8 databases (1990-2014), supplemented by hand searching journals, and references, identifying 2,568 abstracts. Two independent reviews were undertaken of 279 articles, by trained reviewers, using standardised critical appraisal. Eligible studies: primary studies of children aged 13-17 years, with substantiated neglect and/ or emotional maltreatment, containing self-reported features. RESULTS: 19 publications from 13 studies were included, demonstrating associations between both neglect and emotional maltreatment with internalising features (9 studies) including depression, post traumatic symptomatology and anxiety; emotional maltreatment was associated with suicidal ideation, while neglect was not (1 study); neglect was associated with alcohol related problems (3 studies), substance misuse (2 studies), delinquency for boys (1 study), teenage pregnancy (1 study), and general victimization for girls (1 study), while emotionally maltreated girls reported more externalising symptoms (1 study). Dating violence victimization was associated with neglect and emotional maltreatment (2 studies), while emotional abuse of boys, but not neglect, was associated with dating violence perpetration (1 study), and neither neglect nor emotional maltreatment had an association with low self-esteem (2 studies). Neither neglect nor emotional maltreatment had an effect on school performance (1 study), but neglected boys showed greater school engagement than neglected girls (1 study). CONCLUSIONS: If asked, neglected or emotionally maltreated adolescents describe significant difficulties with their mental health, social relationships, and alcohol or substance misuse. Practitioners working with youths who exhibit these features should recognize the detrimental impact of maltreatment at this developmental stage, and identify whether maltreatment is a contributory factor that should be addressed

Rats that differentially respond to cocaine differ in their dopaminergic storage capacity of the nucleus accumbens

Cocaine (COC) inhibits the re-uptake of dopamine. However, the dopamine response to COC also depends on dopamine inside storage vesicles. The aim of this study was to investigate whether rats that differentially respond to COC differ in their dopaminergic storage capacity of the nucleus accumbens. Total and vesicular levels of accumbal dopamine as well as accumbal vesicular monoamine transporter-2 levels were established in high (HR) and low responders (LR) to novelty rats. Moreover, the effects of reserpine (RES) on the COC-induced increase of extracellular accumbal dopamine were investigated. HR displayed higher accumbal levels of total and vesicular dopamine than LR. Moreover, HR displayed more accumbal vesicular monoamine transporters-2 than LR. COC increased extracellular accumbal dopamine more strongly in HR than in LR. A low dose of RES prevented the COC-induced increase of accumbal dopamine in LR, but not in HR. A higher dose of RES was required to inhibit the COC-induced increase of accumbal dopamine in HR. These data demonstrate that HR were marked by a larger accumbal dopaminergic storage pool than LR. It is hypothesized that HR are more sensitive to COC than LR, because COC can release more dopamine from accumbal storage vesicles in HR than in LR