The role of body wall muscles in C. elegans locomotion

Over the past four decades, one of the simplest nervous systems across the animal kingdom, that of the nematode worm C. elegans, has drawn increasing attention. This system is the subject of an intensive concerted effort to understand the behaviour of an entire living animal, from the bottom up and the top down. C. elegans locomotion, in particular, has been the subject of a number of models, but there is as yet no general agreement about the key (rhythm generating) elements. In this paper we investigate the role of one component of the locomotion subsystem, namely the body wall muscles, with a focus on the role of inter-muscular gap junctions. We construct a detailed electrophysiological model which suggests that these muscles function, to a first approximation, as mere actuators and have no obvious rhythm generating role. Furthermore, we show that within our model inter-muscular coupling is too weak to have a significant electrical effect. These results rule out muscles as key generators of locomotion, pointing instead to neural activity patterns. More specifically, the results imply that the reduced locomotion velocity observed in unc-9 mutants is likely to be due to reduced neuronal rather than inter-muscular coupling

Photometry of 40 LMC Cepheids

We present V and I_c CCD photometry for 40 LMC Cepheids at 1 to 3 epochs. This represents a significant increase in the number of LMC Cepheids with $I$-band data, and, as we show, is a useful addition to the sample which can be used to calibrate the period--luminosity relations in these important bands

An integrated neuro-mechanical model of C. elegans forward locomotion

One of the most tractable organisms for the study of nervous systems is the nematode Caenorhabditis elegans, whose locomotion in particular has been the subject of a number of models. In this paper we present a first integrated neuro-mechanical model of forward locomotion. We find that a previous neural model is robust to the addition of a body with mechanical properties, and that the integrated model produces oscillations with a more realistic frequency and waveform than the neural model alone. We conclude that the body and environment are likely to be important components of the worm’s locomotion subsystem

An integrated neuro-mechanical model of C. elegans forward locomotion

One of the most tractable organisms for the study of nervous systems is the nematode Caenorhabditis elegans, whose locomotion in particular has been the subject of a number of models. In this paper we present a first integrated neuro-mechanical model of forward locomotion. We find that a previous neural model is robust to the addition of a body with mechanical properties, and that the integrated model produces oscillations with a more realistic frequency and waveform than the neural model alone. We conclude that the body and environment are likely to be important components of the worm’s locomotion subsystem

Health Insurance and the Labor Supply Decisions of Older Workers: Evidence from the U.S. Department of Veterans Affairs

This paper exploits a major mid-1990s expansion in the U.S. Department of Veterans Affairs health care system to provide evidence on the labor market effects of expanding health insurance availability. Using data from the Current Population Survey, we compare the labor market behavior of older veterans and non-veterans before and after the VA health benefits expansion to test the impact of public health insurance on labor supply. We find that older workers are significantly more likely to decrease work both on the extensive and intensive margins after receiving access to non-employer based insurance. Older workers are also more likely to leave self-employment, a result inconsistent with "job-lock" effects of employer-based insurance, but consistent with a positive income effect from new access to public insurance. Some relatively disadvantaged subpopulations, however, may increase their labor supply after gaining greater access to public insurance, consistent with complementary positive health effects of health care access for these groups. We conclude that this reform has affected employment and retirement decisions, and suggest that future moves toward universal coverage or expansions of Medicare are likely to have significant labor market effects. To illustrate, we calculate that as much as 10% of the difference in retirement rates in the US and Canada may be due to Canada's provision of universal health care.labor supply, job-lock, retirement, older workers, health insurance, VA, Medicare, veteran

Do tasks make a difference? Accounting for heterogeneity of performance of children with reading difficulties on tasks of executive function : findings from a meta-analysis

Research studies have implicated executive functions in reading difficulties (RD). But while some studies have found children with RD to be impaired on tasks of executive function other studies report unimpaired performance. A meta-analysis was carried out to determine whether these discrepant findings can be accounted for by differences in the tasks of executive function that are utilized. A total of 48 studies comparing the performance on tasks of executive function of children with RD with their typically developing peers were included in the meta-analysis, yielding 180 effect sizes. An overall effect size of 0.57 (SE .03) was obtained, indicating that children with RD have impairments on tasks of executive function. However, effect sizes varied considerably suggesting that the impairment is not uniform. Moderator analysis revealed that task modality and IQ-achievement discrepancy definitions of RD influenced the magnitude of effect; however, the age and gender of participants and the nature of the RD did not have an influence. While the children's RD were associated with executive function impairments, variation in effect size is a product of the assessment task employed, underlying task demands, and definitional criteria

Neutral kaon mixing beyond the standard model with nf=2+1 chiral fermions

We compute the hadronic matrix elements of the four-quark operators needed for the study of neutral kaon mixing beyond the Standard Model (SM). We use nf=2+1 flavours of domain-wall fermions (DWF) which exhibit good chiral-flavour symmetry. The renormalization is performed non-perturbatively through the RI-MOM scheme and our results are converted perturbatively to MSbar. The computation is performed on a single lattice spacing a=0.086 fm with a lightest unitary pion mass of 290 MeV. The various systematic errors, including the discretisation effects, are estimated and discussed. Our results confirm a previous quenched study, where large ratios of non-SM to SM matrix elements were obtained.Comment: 5 pages, 4 figures, 1 table. v2 paper version, R3 and B3 corrected, conversion to 2GeV added, references adde

Spousal Labor Market Effects from Government Health Insurance: Evidence from a Veterans Affairs Expansion

Although government expansion of health insurance to older workers leads to labor supply reductions for recipients, there may be spillover effects on the labor supply of affected spouses who are not covered by the programs. In the simplest model, health insurance on the job is paid for in terms of lower compensation on the job. Receiving health insurance exogenous to employment is akin to a positive income shock for the household, causing total household labor supply to drop. However, it is not clear within the household whether this decrease in labor supply will be borne by both spouses or by a specific spouse. We use a mid-1990s expansion of health insurance for U.S. veterans to provide evidence on the effects of expanding health insurance availability on the labor supply of spouses. Using data from the Current Population Survey, we employ a difference-in-differences strategy to compare the labor market behavior of the wives of older male veterans and non-veterans before and after the VA health benefits expansion to test the impact of public health insurance on these spouses. Our findings suggest that although household labor supply may decrease because of the income effect, the more flexible labor supply of wives allows the wife’s labor supply to increase, particularly for those with lower education levels.Health Economics, Labor force participation

Evaluation of initial collector field performance at the Langley Solar Building Test Facility

The thermal performance of the solar collector field for the NASA Langley Solar Building Test Facility is given for October 1976 through January 1977. A 1,180 square meter solar collector field with seven collector designs helped to provide hot water for the building heating system and absorption air conditioner. The collectors were arranged in 12 rows with nominally 51 collectors per row. Heat transfer rates for each row were calculated and recorded along with sensor, insolation, and weather data every five minutes using a minicomputer. The agreement between the experimental and predicted collector efficiencies was generally within five percentage points

The Adjudication and Enforcement of Rights After Brexit

This report records the inaugural meeting and roundtable of the Brexit and Rights Engagement Network (BREN) on Tuesday 3rd July 2018 at Edinburgh Law School. Attendees at the roundtable included network members, fellow academics, representatives of the Scottish Parliament, the Scottish Government, the Scottish Human Rights Commission, the Equality and Human Rights Commission, the legal professions, and NGOs. Two years after the EU Referendum and only a few days after the European Union (Withdrawal) Act 2018 (the 2018 Act) receiving Royal Assent, the Brexit and Rights Engagement Network met for the first time. The purpose of the roundtable was to ignite debate amongst legal scholars and policy makers, and others working in a rights environment relating to interpretation, adjudication and enforcement of rights in the lead up to, and following “Brexit Day,” (March 29, 2019). This report is split into two sections, Part A will consider the adjudication of EU rights, but also their enforcement under the 2018 Act and the Withdrawal Agreement, whilst ‘options for the future’ will be broached in Part B