A biomechanical model of the spine to predict trunk muscle forces: Optimizing the relationship between spinal stability and spinal loading.

The purpose of this study was to develop an optimization model of the spine that, incorporating a measure of spinal stability as a constraint, allowed for realistic predictions of trunk muscle and spine compression forces. A 3-dimensional, 52 muscle, single joint model of the lumbar spine was developed and tested in situations of pure trunk flexor and lateral bend moments. Spinal stability, about each anatomical axis, was calculated at the L4/L5 spinal joint. Estimates of the optimal level of spinal stability, in a given loading situation, obtained through the use of regression equations developed from experimental findings, were utilized as constraints in the optimization model. Two separate optimization cost functions were tested: (1) minimization of the sum of the cubed trunk muscle forces; (2) minimization of the intervetebral force at the L4/L5 joint level. The addition of spinal stability measures, about each anatomical axis, as constraints in the optimization model, caused significantly improved estimates of the compressive forces acting on the spine, as well as improved prediction of trunk muscle forces as a whole. Furthermore, the addition of stability constraints allowed the model to predict activity in muscles functioning as pure antagonists to the applied external moment, a first for optimization models of the spine. Thus, it is concluded that spinal stability plays a vital role in dictating the recruitment patterns of trunk muscles. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2003 .B76. Source: Masters Abstracts International, Volume: 42-02, page: 0572. Adviser: Jim Potvin. Thesis (M.H.K.)--University of Windsor (Canada), 2003

Examining the Neuromuscular and Mechanical Characteristics of the Abdominal Musculature and Connective Tissues: Implications for Stiffening the Lumbar Spine

Research has uncovered an essential role of proper abdominal muscle function in ensuring the health and integrity of the lumbar spine. The anatomical arrangement of the abdominal musculature (rectus abdominis, external oblique, internal oblique, transverse abdominis) and intervening connective tissues is unique in the human body. Despite the hypothesized importance and uniqueness of the abdominal muscles, very little research has been directed to understanding their role from a neuro-mechanical standpoint. Thus, this thesis was designed to study the neuro-activation and mechanical characteristics of the abdominal musculature and connective tissues, with a specific focus on torso stiffening mechanisms. Several experiments were performed and unified around this theme. The first study explored the fundamental relationship between EMG muscle activation recordings and the moments generated by the trunk musculature. This study was novel in that investigation of the abdominal musculature was augmented with consideration of antagonist muscle co-activation. The main finding was that the EMG-moment relationships were quite similar in both the abdominal and extensor muscle groups; however, the form of this relationship differed from that often reported in the literature. Specifically, consideration of antagonist muscle moments linearized the EMG-moment relationship of the agonist muscle groups. Once this activation-moment relationship had been established, the next line of questioning explored the association between torso muscle activation, driven through the abdominals, and torso stiffness. Two studies addressed this issue: the first examined the intrinsic resistance of the torso to bending in the flexion, extension, and lateral bend directions, while varying the levels of torso muscle activation; the second examined the response of the trunk to perturbations while varying the levels of torso muscle activation under the presence of limited reflexes. The first of these two studies demonstrated a rise in trunk stiffness as muscle activation increased over the lower 40% of range of motion. At greater ranges of motion in flexion and lateral bend the trunk appeared to become less stiff as the musculature contracted to higher levels. The latter study revealed substantial spinal displacements in response to trunk perturbations, indicating that in the absence of reflex activity, the stiffness produced by muscular contraction may be inadequate to stiffen the torso to prevent damage to spinal tissues. The fourth study was designed to enable in-vivo observation of abdominal muscle and connective tissue deformation using ultrasound imaging. During relatively simple abdominal contractions, the oblique aponeurosis demonstrated surprising deformation patterns that often exhibited the characteristic of a negative Poisson’s ratio. This was hypothesized to be facilitated by the composite laminate arrangement of the abdominal wall, whereby the loose connective tissues separating layers of collagen fibres may allow for separation of adjacent layers, giving the appearance of structural volume expansion. Further, a lateral displacement of the rectus abdominis muscle was noted in a majority of contractions, highlighting the dominance of the laterally oriented forces generated by the oblique muscles. The final study questioned, at a basic level, the nature of the anatomical arrangement of the abdominal muscle-connective tissue network. Examining the contraction of the rat abdominal wall uncovered the transfer of muscularly generated force and stiffness through the connective tissues binding the layered muscles. This suggests a functionality of the abdominal wall as a composite laminate structure, allowing substantial multi-directional stiffness to be generated and transmitted around the torso, thereby enhancing the ability to effectively stabilize the spine

Genetic effects on gene expression across human tissues

Characterization of the molecular function of the human genome and its variation across individuals is essential for identifying the cellular mechanisms that underlie human genetic traits and diseases. The Genotype-Tissue Expression (GTEx) project aims to characterize variation in gene expression levels across individuals and diverse tissues of the human body, many of which are not easily accessible. Here we describe genetic effects on gene expression levels across 44 human tissues. We find that local genetic variation affects gene expression levels for the majority of genes, and we further identify inter-chromosomal genetic effects for 93 genes and 112 loci. On the basis of the identified genetic effects, we characterize patterns of tissue specificity, compare local and distal effects, and evaluate the functional properties of the genetic effects. We also demonstrate that multi-tissue, multi-individual data can be used to identify genes and pathways affected by human disease-associated variation, enabling a mechanistic interpretation of gene regulation and the genetic basis of diseas

Abdominal aortic aneurysm is associated with a variant in low-density lipoprotein receptor-related protein 1

Abdominal aortic aneurysm (AAA) is a common cause of morbidity and mortality and has a significant heritability. We carried out a genome-wide association discovery study of 1866 patients with AAA and 5435 controls and replication of promising signals (lead SNP with a p value < 1 × 10-5) in 2871 additional cases and 32,687 controls and performed further follow-up in 1491 AAA and 11,060 controls. In the discovery study, nine loci demonstrated association with AAA (p < 1 × 10-5). In the replication sample, the lead SNP at one of these loci, rs1466535, located within intron 1 of low-density-lipoprotein receptor-related protein 1 (LRP1) demonstrated significant association (p = 0.0042). We confirmed the association of rs1466535 and AAA in our follow-up study (p = 0.035). In a combined analysis (6228 AAA and 49182 controls), rs1466535 had a consistent effect size and direction in all sample sets (combined p = 4.52 × 10-10, odds ratio 1.15 [1.10-1.21]). No associations were seen for either rs1466535 or the 12q13.3 locus in independent association studies of coronary artery disease, blood pressure, diabetes, or hyperlipidaemia, suggesting that this locus is specific to AAA. Gene-expression studies demonstrated a trend toward increased LRP1 expression for the rs1466535 CC genotype in arterial tissues; there was a significant (p = 0.029) 1.19-fold (1.04-1.36) increase in LRP1 expression in CC homozygotes compared to TT homozygotes in aortic adventitia. Functional studies demonstrated that rs1466535 might alter a SREBP-1 binding site and influence enhancer activity at the locus. In conclusion, this study has identified a biologically plausible genetic variant associated specifically with AAA, and we suggest that this variant has a possible functional role in LRP1 expression

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

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

Severe early onset preeclampsia: short and long term clinical, psychosocial and biochemical aspects

Preeclampsia is a pregnancy specific disorder commonly defined as de novo hypertension and proteinuria after 20 weeks gestational age. It occurs in approximately 3-5% of pregnancies and it is still a major cause of both foetal and maternal morbidity and mortality worldwide1. As extensive research has not yet elucidated the aetiology of preeclampsia, there are no rational preventive or therapeutic interventions available. The only rational treatment is delivery, which benefits the mother but is not in the interest of the foetus, if remote from term. Early onset preeclampsia (<32 weeks’ gestational age) occurs in less than 1% of pregnancies. It is, however often associated with maternal morbidity as the risk of progression to severe maternal disease is inversely related with gestational age at onset2. Resulting prematurity is therefore the main cause of neonatal mortality and morbidity in patients with severe preeclampsia3. Although the discussion is ongoing, perinatal survival is suggested to be increased in patients with preterm preeclampsia by expectant, non-interventional management. This temporising treatment option to lengthen pregnancy includes the use of antihypertensive medication to control hypertension, magnesium sulphate to prevent eclampsia and corticosteroids to enhance foetal lung maturity4. With optimal maternal haemodynamic status and reassuring foetal condition this results on average in an extension of 2 weeks. Prolongation of these pregnancies is a great challenge for clinicians to balance between potential maternal risks on one the eve hand and possible foetal benefits on the other. Clinical controversies regarding prolongation of preterm preeclamptic pregnancies still exist – also taking into account that preeclampsia is the leading cause of maternal mortality in the Netherlands5 - a debate which is even more pronounced in very preterm pregnancies with questionable foetal viability6-9. Do maternal risks of prolongation of these very early pregnancies outweigh the chances of neonatal survival? Counselling of women with very early onset preeclampsia not only comprises of knowledge of the outcome of those particular pregnancies, but also knowledge of outcomes of future pregnancies of these women is of major clinical importance. This thesis opens with a review of the literature on identifiable risk factors of preeclampsia