Modelling the neuromechanics of exploration and taxis in larval Drosophiila

The Drosophila larva is emerging as a useful tool in the study of complex behaviours, due to its relatively small size, its genetic tractability, and its varied behavioural repertoire. The larva executes a stereotypical exploratory routine that appears to consist of stochastic alternation between straight peristaltic crawling and reorientation events through lateral bending. The larva performs taxis by biasing this behavioural pattern, allowing it to move up or down attractive and aversive stimulus gradients. Existing explanations of exploration and taxis behaviour often neglect the larva's embodiment, focusing on central pattern generation and decision making circuits within the nervous system. In Chapter 1 of this thesis, I review the current state of knowledge regarding larval peristalsis, exploration, and taxis behaviours, as well as existing theories of their generation. I argue that an understanding of the animal's embodiment should lead to a deeper understanding of its behaviour. In Chapter 2, I present a model of the axial mechanics of the larva, and demonstrate how the animal's body physics can be exploited to produce peristalsis by using segmentally localised, positive feedback of strain rate. The mechanical model includes viscoelastic tissue mechanics, muscular inputs, and substrate interaction while sensory feedback is modelled as a linear feedback control law. In Chapter 3, I extend the mechanical model to study motion in the plane, including both axial and transverse deformations of the body. The feedback law is replaced by a simple model of the larval nervous system. The model includes both a segmentally localised reflex arc as well as long-range, mutual inhibition between segments. The complete model is capable of generating both peristalsis and spontaneous reorientation, leading to emergent exploration behaviour in the form of a deterministic superdiffusion process grounded in the chaotic mechanics of the larva's body. In Chapter 4, I consider taxis behaviour. I introduce a transverse reflex capable of modulating the effective transverse viscosity of the larval body. When the larva is experiencing an increasing attractive (aversive) stimulus, the reflex acts to increase (decrease) the effective transverse viscosity, causing bending to occur less (more) easily. As a result, the model larvae approach attractive stimuli and avoid aversive stumuli. On a population level, I show that the transverse reflex can be thought of as biasing the model animals towards sub- or super-diffusion. I compare the statistics of this behaviour to those of the real larva. In Chapter 5, I shift focus to engineered soft systems. Having successfully deployed an energy-based modelling approach in Chapters 2--4, I argue for the adoption of an energy-focused (specifically, port-Hamiltonian) approach within the field of soft robotics. In Chapter 6, I present some initial theoretical extensions to the models presented in chapter 2--4. I first focus on the mechanics of self-righting and rolling behaviours, before modelling the ventral nerve cord of the larva using a ring attractor architecture. Finally, in Chapter 7, I summarise the results of the previous chapters and discuss directions for future research

A Community-Based Obesity Prevention Program Decreased the Body Mass Index of University-Affiliated Participants

Obesity is a national health concern and the focus of many health promotion programs. The purpose of this study was to evaluate the behavioral impact of a 12-week obesity prevention program on a university campus. Participants were provided questionnaires with weights, heights, and body mass indices (BMIs) determined at the pre-phase weigh-in and post-phase weigh-out. At the weigh-in, participants received pedometers and information about upcoming educational sessions to assist them with reaching their health behavior goals. A total of 247 (38.2% of 646) individuals (79.4% women) completed the program. A mean weight loss of 1.8 kg caused a decrease in BMI from 29.3 at weigh-in to 28.7 at weigh-out (p = .002). Pre- and post-questionnaires indicated increases (p \u3c 0.001) in physical activity; using pedometers; and intakes of fruits, vegetables, and water at the end of the program. The 6-month follow-up questionnaire (33.2% response rate) indicated healthy habits were being maintained for fruit and vegetable consumption. Further intervention development to incorporate innovative strategies for promoting healthy behaviors among students and employees on university campuses could help decrease the prevalence of obesity

Approaches and considerations for the assessment of immunotoxicity for environmental chemicals: A workshop summary

AbstractAs experience is gained with toxicology testing and as new assays and technologies are developed, it is critical for stakeholders to discuss opportunities to advance our overall testing strategies. To facilitate these discussions, a workshop on practices for assessing immunotoxicity for environmental chemicals was held with the goal of sharing perspectives on immunotoxicity testing strategies and experiences, developmental immunotoxicity (DIT), and integrated and alternative approaches to immunotoxicity testing. Experiences across the chemical and pharmaceutical industries suggested that standard toxicity studies, combined with triggered-based testing approaches, represent an effective and efficient approach to evaluate immunotoxic potential. Additionally, discussions on study design, critical windows, and new guideline approaches and experiences identified important factors to consider before initiating DIT evaluations including assay choice and timing and the impact of existing adult data. Participants agreed that integrating endpoints into standard repeat-dose studies should be considered for fulfilling any immunotoxicity testing requirements, while also maximizing information and reducing animal use. Participants also acknowledged that in vitro evaluation of immunosuppression is complex and may require the use of multiple assays that are still being developed. These workshop discussions should contribute to developing an effective but more resource and animal efficient approach for evaluating chemical immunotoxicity

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Optimasi Portofolio Resiko Menggunakan Model Markowitz MVO Dikaitkan dengan Keterbatasan Manusia dalam Memprediksi Masa Depan dalam Perspektif Al-Qur`an

Risk portfolio on modern finance has become increasingly technical, requiring the use of sophisticated mathematical tools in both research and practice. Since companies cannot insure themselves completely against risk, as human incompetence in predicting the future precisely that written in Al-Quran surah Luqman verse 34, they have to manage it to yield an optimal portfolio. The objective here is to minimize the variance among all portfolios, or alternatively, to maximize expected return among all portfolios that has at least a certain expected return. Furthermore, this study focuses on optimizing risk portfolio so called Markowitz MVO (Mean-Variance Optimization). Some theoretical frameworks for analysis are arithmetic mean, geometric mean, variance, covariance, linear programming, and quadratic programming. Moreover, finding a minimum variance portfolio produces a convex quadratic programming, that is minimizing the objective function ðð¥with constraintsð ð 𥠥 ðandð´ð¥ = ð. The outcome of this research is the solution of optimal risk portofolio in some investments that could be finished smoothly using MATLAB R2007b software together with its graphic analysis

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

Search for stop and higgsino production using diphoton Higgs boson decays

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass