6,345 research outputs found
Formula One Car Downforce Analysis
This document entails the background and process for conducting a project geared towards analyzing Formula One car front wings. The design process includes creating a three-dimensional CAD rendering of three Formula One cars and using CFD to analyze their performance via downforce at various speeds. A comparison of the measured downforce levels is compared to real-world data using Amazon Web Service data collection and video coverage from a selected event. Results indicate that wing geometry has a significant effect on its respective performance
Mechanical Demands of the Hang Power Clean and Jump Shrug: A Joint-level Perspective
The purpose of this study was to investigate the joint- and load-dependent changes in the mechanical demands of the lower extremity joints during the hang power clean (HPC) and the jump shrug (JS). Fifteen male lacrosse players were recruited from an NCAA DI team, and completed three sets of the HPC and JS at 30%, 50%, and 70% of their HPC 1-Repetition Maximum (1-RM HPC) in a counterbalanced and randomized order. Motion analysis and force plate technology were used to calculate the positive work, propulsive phase duration, and peak concentric power at the hip, knee, and ankle joints. Separate three-way analysis of variances were used to determine the interaction and main effects of joint, load, and lift type on the three dependent variables. The results indicated that the mechanics during the HPC and JS exhibit joint-, load-, and lift-dependent behavior. When averaged across joints, the positive work during both lifts increased progressively with external load, but was greater during the JS at 30% and 50% of 1-RM HPC than during the HPC. The JS was also characterized by greater hip and knee work when averaged across loads. The joint-averaged propulsive phase duration was lower at 30% than at 50% and 70% of 1-RM HPC for both lifts. Furthermore, the load-averaged propulsive phase duration was greater for the hip than the knee and ankle joint. The jointaveraged peak concentric power was the greatest at 70% of 1-RM for the HPC and at 30% to 50% of 1-RM for the JS. In addition, the joint-averaged peak concentric power of the JS was greater than that of the HPC. Furthermore, the load-averaged peak knee and ankle concentric joint powers were greater during the execution of the JS than the HPC. However, the loadaveraged power of all joints differed only during the HPC, but was similar between the hip and knee joints for the JS. Collectively, these results indicate that compared to the HPC the JS is characterized by greater hip and knee positive joint work, and greater knee and ankle peak concentric joint power, especially if performed at 30 and 50% of 1-RM HPC. This study provides important novel information about the mechanical demands of two commonly used exercises and should be considered in the design of resistance training programs that aim to improve the explosiveness of the lower extremity joints
Individual Differences in Personality Predict Externalizing Versus Internalizing Outcomes Following Sexual Assault
For some women, the experience of being sexually assaulted leads to increases in externalizing behaviors, such as problem drinking and drug use; for other women, the experience of being assaulted leads to increases in internalizing distress, such as depression or anxiety. It is possible that preassault personality traits interact with sexual assault to predict externalizing or internalizing distress. We tested whether concurrent relationships among personality, sexual assault, and distress were consistent with such a model. We surveyed 750 women just prior to their freshman year at a large public university. Consistent with our hypotheses, at low levels of negative urgency (the tendency to act rashly when distressed), sexual assault exposure had little relationship to problem drinking and drug use. At high levels of negative urgency, being sexually assaulted was highly associated with those externalizing behaviors. At low levels of internalizing personality traits, being assaulted had little relationship to depression and anxiety symptoms; at high levels of the traits, assault experience was highly related to those symptoms. Personality assessment could lead to more person-specific postassault interventions
An Exploration of Sexual Victimization and Academic Performance Among College Women
The literature has documented the widespread nature of sexual assault victimization among college women. While the aftermath of violence against university women has also received focus, that is, documenting trauma-related sequelae; risk factors; reporting patterns; and legal interventions, the impact on academic performance has not received adequate attention in the literature. The primary purpose of this study was to explore the association of rape and sexual assault with academic performance among college women. Its specific aims included the following: to compare high school and college sexual assault experiences with collegiate grade point averages (GPAs) at key points in time; to examine any differences in GPA by type of sexual assault; to urge researchers studying retention and persistence patterns or sexual assault among college students to ensure that the relationship between the two is included in research designs; and to recommend that academic institutions expand programming on retention to include rape and sexual assault among the risk factors associated with a lack of persistence
Ternatin and improved synthetic variants kill cancer cells by targeting the elongation factor-1A ternary complex.
Cyclic peptide natural products have evolved to exploit diverse protein targets, many of which control essential cellular processes. Inspired by a series of cyclic peptides with partially elucidated structures, we designed synthetic variants of ternatin, a cytotoxic and anti-adipogenic natural product whose molecular mode of action was unknown. The new ternatin variants are cytotoxic toward cancer cells, with up to 500-fold greater potency than ternatin itself. Using a ternatin photo-affinity probe, we identify the translation elongation factor-1A ternary complex (eEF1A·GTP·aminoacyl-tRNA) as a specific target and demonstrate competitive binding by the unrelated natural products, didemnin and cytotrienin. Mutations in domain III of eEF1A prevent ternatin binding and confer resistance to its cytotoxic effects, implicating the adjacent hydrophobic surface as a functional hot spot for eEF1A modulation. We conclude that the eukaryotic elongation factor-1A and its ternary complex with GTP and aminoacyl-tRNA are common targets for the evolution of cytotoxic natural products
Evaluation of Content and Accessibility of Orthopaedic Trauma Fellowship Websites
Background: Residents frequently use the internet to find material on fellowship programs. The Orthopaedic Trauma Association (OTA) website serves as a central hub for information on an orthopaedic trauma fellowship (OTF). This study aims to evaluate the accessibility, content, and perceived importance of OTF websites.
Methods: We reviewed the 49 OTFs accredited by the OTA fellowship database as of January 2014. We searched for corresponding OTF websites by using the provided OTA hyperlinks and conducting a separate Google search of program location and institution. Links to websites of general orthopaedic programs were not counted. Content of OTF websites was analyzed by noting the presence or absence of specific items in fellow education (11 items) and recruitment (5 items).
Results: Of 49 OTFs, a total of 39 (80%) websites specific to the fellowship were identified by searching the OTA database and Google browser. Seven (14%) programs listed on the OTA database provided links directly to fellowship programs. Most programs (28; 57%) did not provide links to specific OTFs or provided non-functional links on the OTA website. Of the 39 accessible OTF websites, a total of 24 (61%) had complete information regarding recruitment and 14 (36%) provided complete details on education.
Conclusions: Most accredited OTFs do not adequately use the internet to provide easily accessible and complete information. Further details (especially regarding the role, education, and schedule) would help prospective candidates in thoroughly evaluating programs. The discrepancy in content and accessibility can hinder prospective fellows from appropriately investigating fellowship programs
Nonsuicidal Self-injury as a Risk Factor for Purging Onset: Negatively Reinforced Behaviours that Reduce Emotional Distress
Both nonsuicidal self-injury (NSSI) and purging behaviour are thought to involve harm to the self. The acquired capability for self-harm model holds that engaging in one self-harming behaviour increases the capability to tolerate harm to the self, thus increasing risk for engaging on other such behaviours. In addition, both behaviours are thought to serve the similar function of relief from distress. We thus tested whether engagement in one of these behaviours predicts the subsequent onset of the other. In a longitudinal design, 1158 first-year college women were assessed for purging and NSSI at two time points. Engagement in NSSI at time 1 predicted the college onset of purging behaviour 9 months later (OR = 2.20, p \u3c .04, CI = 1.07-4.19) beyond prediction from time 1 binge behaviour, and purging behaviour at time 1 predicted the subsequent onset of NSSI (OR = 6.54, p \u3c .01, CI = 1.71-25.04). These findings are consistent with the acquired capability for harm model and with the possibility that the two behaviours serve a similar function
Comparison of antimicrobial resistance phenotypes and genotypes in enterotoxigenic Escherichia coli isolated from Australian and Vietnamese pigs
This study aimed to compare the antibiogram phenotype and carriage of antimicrobial resistance genes (ARGs) of 97 porcine multidrug-resistant (MDR) enterotoxigenic Escherichia coli (ETEC) isolates obtained from Vietnam and 117 porcine MDR-ETEC obtained from Australia, two countries with different antimicrobial regulation systems. An antimicrobial resistance index (ARI) was calculated to quantify their potential significance to public health. Both Vietnamese and Australian isolates had moderate to high levels of resistance to commonly used antibiotics (ampicillin, tetracycline and sulphonamides). None of the Australian isolates were resistant to fluoroquinolones or third-generation cephalosporins and none possessed associated plasmid-mediated ARGs. However, 23.1% of Australian isolates were resistant to gentamicin owing to ARGs associated with apramycin or neomycin resistance [e.g. aac(3)-IV] that impart cross-resistance to gentamicin. Whilst Vietnamese isolates carried aminoglycoside ARGs, 44.4% of commercial pig isolates were resistant to gentamicin in comparison with 0% of village pig isolates. The plasmid-mediated fluoroquinolone ARG qnrB was commonly detected in Vietnamese isolates (52.3% commercial, 44.1% village), but phenotypic resistance was low (3.2% and 11.8%, respectively). The mean ARI for Vietnamese isolates (26.0) was significantly different (P < 0.001) from the mean ARI for Australian isolates (19.8), primarily reflecting fluoroquinolone resistance in the former collection. This comparison suggests the effectiveness of regulations that slow the dissemination of 'critical' resistance by restricting the availability of important classes of antimicrobials
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