Evidence for an additive inhibitory component of contrast adaptation

The latency of visual responses generally decreases as contrast increases. Recording in the lateral geniculate nucleus (LGN), we find that response latency increases with increasing contrast in ON cells for some visual stimuli. We propose that this surprising latency trend can be explained if ON cells rest further from threshold at higher contrasts. Indeed, while contrast changes caused a combination of multiplicative gain change and additive shift in LGN cells, the additive shift predominated in ON cells. Modeling results supported this theory: the ON cell latency trend was found when the distance-to-threshold shifted with contrast, but not when distance-to-threshold was fixed across contrasts. In the model, latency also increases as surround-to-center ratios increase, which has been shown to occur at higher contrasts. We propose that higher-contrast full-field stimuli can evoke more surround inhibition, shifting the potential further from spiking threshold and thereby increasing response latency

THE MENTAL HEALTH OF MOTHERS AND FATHERS BEFORE AND AFTER COHABITATION AND MARITAL DISSOLUTION

Using data from years one and three of the Fragile Families and Child Well-being Study, changes in depressive and anxious symptoms are compared for mothers and fathers who: 1) dissolve a cohabitating union versus remain intact; 2) dissolve a marital union versus remain intact; and 3) dissolve a cohabiting as compared to a marital union. In order to take into account potential sources of third variable bias from selection factors that differentiate those who are in cohabitations from those who are in marriages, mothers and fathers were matched on several sociodemographic control variables that research has demonstrated to be related to union formation and mental health outcomes. Results indicated that fathers who dissolve cohabitating or marital unions have greater increases in depressive and anxious symptoms over time than those who remain in their unions. In contrast, mothers increased in depressive and anxious symptoms, regardless of the type or stability of the union. For both mothers and fathers, no differences were found in change in mental health by type of union dissolution. In this low income sample of parents, results suggest that the impact of cohabitation and marital dissolution on mental health are similar in magnitude.Depression, fragile families, marriage, cohabitation, income, mental health

IMPLICATIONS OF VIOLENT AND CONTROLLING UNIONS FOR MOTHERS’ MENTAL HEALTH AND LEAVING

We used two waves of the Fragile Families Study (N = 2639) to examine links between control and violence with maternal mental health and relationship dissolution. Mothers in controlling-only or controlling and violent unions had more symptoms of depression and anxiety and greater odds of dissolution than mothers not experiencing violence or control. Over time, all mothers increased in depressive symptoms, but the magnitude of the increase in depressive symptoms was greatest for mothers in violent and controlling stable unions followed by those in controlling-only stable unions. Mothers dissolving violent and/or controlling unions also experienced increases depressive symptoms over time. Results indicate negative consequences for both mothers who remain in and leave violent and controlling unions.

Infertility problems and mental health symptoms in a community-based sample: depressive symptoms among infertile men, but not women

Most researchers agree that men’s and women’s experiences of infertility are fundamentally different, and impacts upon the nature of psychological distress encountered. However, design flaws, including non-random samples unrepresentative of the general population, compromise many existing studies. Data derived from a random general community sample provides prevalence of current infertility, and permits examination of longitudinal associations between mental health symptoms and infertility among 1,978 participants aged 28-32 years. In the previous 12-months, infertility was experienced by 2.1% and 5.4% partnered men and women. Infertility independently predicted depressive symptomatology in men, and anxiety symptoms among women. Gender differences were sustained, even controlling for prior depression and anxiety. Health professionals are encouraged to proactively enquire about affective symptoms experienced by both women and men with infertility problems

Benzo-pyrones for reducing and controlling lymphoedema of the limbs.

Background Lymphoedema is the accumulation of excess fluid in the body caused by obstruction of the lymphatic drainage mechanisms. Treatment with Benzo-pyrones is thought to reduce fluid forming in the subcutaneous tissues and reduce pain and discomfort of the affected area. Objectives To assess the effectiveness of benzo-pyrones compared to placebo in the management of lymphoedema. Search strategy We searched the Cochrane Breast Cancer Group register (September 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 4,2003), MEDLINE, EMBASE, CINAHL, UnCover, PASCAL, SIGLE, reference lists produced by The British Lymphology Society, the National Research Register (NRR) and The International Society of Lymphology congress proceedings. Selection criteria Randomised controlled trials comparing Benzo-pyrones with placebo. Data collection and analysis Trials were selected for eligibility and tested for quality by two blinded reviewers who independently extracted data. Meta-analysis was not performed due to the poor quality of the trials. Main results Fifteen trials were included. Three oxerutin trials tested the same dose over 6 months against placebo and included a total of 127 participants (data were available for 81). There were insufficient data from these to calculate the per cent reduction or increase in baseline excess limb volume. One trial testing Cyclo 3 Fort (approved name) was found (57 participants) but insufficient data was provided to allow a proper analysis of its findings. A single trial of Daflon (approved name) was found (104 participants) but this also provided insufficient information to reach a conclusion about the effectiveness of the drug. Three trials of coumarin combined with troxerutin were found which tested two different doses of the drug against each other with no placebo, however participant numbers and baseline data were not provided. Eight trials of coumarin were identified. Two of these reported the same trial and the other potentially also referred to the same trial but this could not be confirmed. A further two papers also appeared to refer to the same trial but again this was unconfirmed. Five studies added anti-filarial drugs to the interventions tested. Participant data could not be extracted and the reporting of outcome measures in most was unclear. Loprinzi's 1999 trial was reported in more detail but its conclusions were very much at odds with other findings. Authors' conclusions It is not possible to draw conclusions about the effectiveness of Benzopyrones in the management of lymphoedema from the current available trials

Some problems with a behavioristic account of early group pretense

Free to read on publishers website In normal child development, both individual and group pretense first emerges at approximately two years of age. The metarepresentational account of pretense holds that children already have the concept PRETEND when they first engage in early group pretense. A behavioristic account suggests that early group pretense is analogous to early beliefs or desires and thus require no mental state concepts. I argue that a behavioral account does not explain the actual behavior observed in children and it cannot explain how children come to understand that a specific action is one of pretense versus one of belief. I conclude that a mentalistic explanation of pretense best explains the behavior under consideration

The reduction of the critical current in Nb3Sn cables under transverse loads

The degradation of the critical current of impregnated Rutherford type Nb3Sn cables was investigated as a function of the applied transverse load and magnetic field. The cable is made of modified jelly-roll-type strand material and has a keystone angle of 1.0°. The voltage-current characteristics were determined for the magnetic field ranging from 2 to 11 T and transverse pressure up to 250 MPa on the cable surface. It was found that the 48-strand cable, made of strands with six elements in the matrix, showed a larger critical current degradation than the 26-strand cable with 36 elements per strand. The global degradation of the 48-strand cable was 63% at 150 MPa, and 40% at 150 MPa for the 26-strand cable. Microanalysis of the cross-section before and after compression is presented, showing significant permanent damage to the superconducting strands