1,177 research outputs found

    Duct liner optimization for turbomachinery noise sources

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    An acoustical field theory for axisymmetric, multisectioned lined ducts with uniform flow profiles was combined with a numerical minimization algorithm to predict optimal liner configurations having one, two, and three sections. Source models studied include a point source located on the axis of the duct and rotor/outlet-stator viscous wake interaction effects for a typical research compressor operating at an axial flow Mach number of about 0.4. For this latter source, optimal liners for equipartition-of energy, zero-phase, and least-attenuated-mode source variations were also calculated and compared with exact results. It is found that the potential benefits of liner segmentation for the attenuation of turbomachinery noise is greater than would be predicted from point source results. Furthermore, effective liner design requires precise knowledge of the circumferential and radial modal distributions

    Protection-motivated behaviors of organizational insiders

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    Protecting information from a wide variety of security threats is an important and sometimes daunting organizational activity. Instead of solely relying on technological advancements to help solve human problems, managers within firms must recognize and understand the roles that organizational insiders have in the protection of information. The systematic study of human influences on organizational information security is termed behavioral information security (Fagnot 2008; Stanton, Stam, Mastrangelo, and Jolton 2006), and it affirms that the protection of organizational information assets is best achieved when the detrimental behaviors of organizational insiders are effectively deterred and the beneficial activities of these individuals are appropriately encouraged. Relative to the former, the latter facet has received little attention in the academic literature. Given this opportunity, this dissertation explicitly focuses upon protective behaviors that help promote the protection of organizational information resources. These behaviors are termed protection-motivated behaviors (PMBs) and are defined as the volitional behaviors organizational insiders can enact that protect (1) organizationally-relevant information within their firms and (2) the computer-based information systems in which that information is stored, collected, disseminated, and/or manipulated from information-security threats. Each of the chapters herein is dedicated to fostering knowledge about these beneficial behaviors and acts as a complement to existing research in order to more fully support the entire scope of behavioral information security. Chapter 2 focuses upon the development of a formal typology of PMBs and relies on the complementary classification techniques of Multidimensional Scaling (MDS), Property Fitting (ProFit) analysis, and cluster analysis. 67 individual PMBs were discovered, and the above classification techniques uncovered a three-dimensional perceptual space common among organizational insiders regarding PMBs. This space verifies that insiders differentiate PMBs according to whether the behaviors (1) require minor or continual level of improvements within organizations, (2) are widely or narrowly standardized and applied throughout various organizations, and (3) are a reasonable or unreasonable request of organizations to make of their insiders. 14 unique clusters were also discovered during this process, which finding further assists information security researchers in their understanding of how organizational insiders perceive the behaviors that help protect information assets. Chapter 3 uses the findings from Chapter 2 to develop a self-report measure of insiders\u27 engagement in PMBs within their organizations. PMBs are modeled as a multiple indicators and multiple causes (MIMIC) structure (Joreskog and Goldberger 1975) with the clusters found in Chapter 2 being first-order, formative constructs of the overall, second-order PMB measure. These clusters explain over 70% of the variance in overall PMB activity. The nomological validity of the newly constructed measure is also empirically examined in this chapter, and the results largely support the conceptualization of PMBs. Chapter 4 places the measure developed in the previous chapter in a motivational model founded on Protection Motivation Theory (PMT) (Rogers 1975, 1983). The findings from covariance-based structural equation modeling show that insiders\u27 motivation to engage in PMBs is largely influenced by the perceived efficacy of protective responses and potential adaptive response costs—both components of the coping appraisal process. Fear, however, is shown to have little influence on these motivational levels. In addition to the PMT components, several rival explanations are examined. Job satisfaction and management support are found to significantly explain variance in organizational insiders\u27 motivation to engage in PMBs. In summary, this dissertation comprises a significant work in the field of behavioral information security by conducting 33 semi-structured interviews, eliciting the participation of 13 subject matter experts, and issuing 6 individual data collections. When these efforts are combined, the results of this dissertation are based on the responses of more than 1,700 organizational insiders. The findings help both information security researchers and managers within organizations more fully understand the protective role that organizational insiders play in the protection of information resources

    Changes in Power Output in NCAA Football Linemen During Competitive Season

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    Changes in Power Output in NCAA Football Linemen During Competitive Season. Posey, Q., R. Cole, and J. Priest, Tarleton State University, Stephenville, TX 76402 Introduction Measuring power is a practice currently being developed by researchers. An available tool is the TENDO Weightlifting Analyzer (TWA). Although the TWA is a common research tool, there is little published research. The purpose of this study is to analyze OL and DL power output during in-season football. Methods Experimental Approach Seventeen NCAA division II football players in the Lone Start Conference were monitored during organized in-season weight training workouts. TWA measured and recorded their last set of squat. Bio feedback provided by the TWA was used to analyze each group. Subjects Seventeen NCAA division II football players (Age 21.1 ± 4.6 yrs, Ht. 1.6 ± 0.01m, Wt. 123.1 ± 7.4 kg , BMI 35.3 ± 3.2 kg.m-2), volunteered for the study, and had previously trained at least twice per week for 12 weeks. Subjects were familiarized with the TWA and squat protocol during pre-season. Protocol All subjects were required to lift four times a week. On the third workout of every week subjects back-squatted. All subjects completed a standardized warm-up. Subjects determine their own lifting weight. Researchers monitored squats and emphasized bar speed. The TWA was attached to the outside of the bar and measured average power (AP) and peak power (PP) output. Measurements were uploaded from the TWA into TENDO Sports Machine computer program and exported to Microsoft Excel®. Results Repeated measures ANOVA revealed no change in AP (F(3,45)=0.996, p\u3e.05), change in overall PP (F(3,45)=15.3, p\u3c.001) across 4 measures of the competitive season. No group interaction for AP (F(3,45)=.488, p\u3e.05), but PP by group interaction (F(3,45)=6.07, p=.001). AP 1 (W) AP 2 (W) AP 3 (W) AP 4 (W) PP 1 (W) PP 2 (W) PP 3 (W) PP4 (W) OL 911 ± 136 910 ± 124 850 ± 89 893 ± 19 1507 ± 251 1775 ± 258 1207 ± 141 1690 ±142 DL 947 ± 214 905 ± 184 904 ± 184 880 ± 110 1605 ± 343 1728 ± 487 1637 ± 317 1801 ± 215 Table 1. Average (AP) and Peak Power (PP) of Offensive (OL) and Defensive Linesmen (DL) During Competitive Season. Discussion The competitive football season produced normal bumps, bruises, and sprains which impacted the results obtained from bi-weekly measures of AP and PP. The observed changes in PP were attributed to the changes in peak bar velocities for this instantaneous measure, whereas the stability of AP was explained by the less volatile factor of average bar velocities. Conclusion Organized in-season weight training activities are effective at maintaining power output of offensive and defensive linemen

    The Cauchy-Schlomilch transformation

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    The Cauchy-Schl\"omilch transformation states that for a function ff and a, b>0a, \, b > 0, the integral of f(x2)f(x^{2}) and af((ax−bx−1)2af((ax-bx^{-1})^{2} over the interval [0,∞)[0, \infty) are the same. This elementary result is used to evaluate many non-elementary definite integrals, most of which cannot be obtained by symbolic packages. Applications to probability distributions is also given

    Protection of Soil From Erosion by Swiftly Flowing Water

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    Changing direction of flow in a watercourse is accompanied by non-hydrostatic pressure distribution, fixed in location where the curvature is steady, and constantly shifting in location and magnitude when the deviations arc due to turbulence. The response of the subflow in the boundary soil, from high pressure areas to low pressure areas, is practically instantaneous. Erosion (or rupture of waterproof linings) is most likely to occur at the low pressure areas, where the direction of flow is from the soil into the watercourse. Terzaghi\u27s reverse filter can be used to prevent removal of soil as long as the topmost layers of the filter remain stable. This is achieved by using the ancient Chinese rock snake or sausage. The economy and practicality of the method for new and old erosion problems are under continuing investigation, as illustrated by a 16 mm silent motion picture prepared by the author

    Chop (Ddit3) Is Essential for D469del-COMP Retention and Cell Death in Chondrocytes in an Inducible Transgenic Mouse Model of Pseudoachondroplasia

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    Cartilage oligomeric matrix protein (COMP), a secreted glycoprotein synthesized by chondrocytes, regulates proliferation and type II collagen assembly. Mutations in the COMP gene cause pseudoachondroplasia and multiple epiphyseal dysplasia. Previously, we have shown that expression of D469del-COMP in transgenic mice causes intracellular retention of D469del-COMP, thereby recapitulating pseudoachondroplasia chondrocyte pathology. This inducible transgenic D469del-COMP mouse is the only in vivo model to replicate the critical cellular and clinical features of pseudoachondroplasia. Here, we report developmental studies of D469del-COMP-induced chondrocyte pathology from the prenatal period to adolescence. D469del-COMP retention was limited prenatally and did not negatively affect the growth plate until 3 weeks after birth. Results of immunostaining, transcriptome analysis, and qRT-PCR suggest a molecular model in which D469del-COMP triggers apoptosis during the first postnatal week. By 3 weeks (when most chondrocytes are retaining D469del-COMP), inflammation, oxidative stress, and DNA damage contribute to chondrocyte cell death by necroptosis. Importantly, by crossing the D469del-COMP mouse onto a Chop null background (Ddit3 null), thereby eliminating Chop, the unfolded protein response was disrupted, thus alleviating both D469del-COMP intracellular retention and premature chondrocyte cell death. Chop therefore plays a significant role in processes that mediate D469del-COMP retention. Taken together, these results suggest that there may be an optimal window before the induction of significant D469del-COMP retention during which endoplasmic reticulum stress could be targeted

    Independent large scale duplications in multiple M. tuberculosis lineages overlapping the same genomic region

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    Mycobacterium tuberculosis, the causative agent of most human tuberculosis, infects one third of the world's population and kills an estimated 1.7 million people a year. With the world-wide emergence of drug resistance, and the finding of more functional genetic diversity than previously expected, there is a renewed interest in understanding the forces driving genome evolution of this important pathogen. Genetic diversity in M. tuberculosis is dominated by single nucleotide polymorphisms and small scale gene deletion, with little or no evidence for large scale genome rearrangements seen in other bacteria. Recently, a single report described a large scale genome duplication that was suggested to be specific to the Beijing lineage. We report here multiple independent large-scale duplications of the same genomic region of M. tuberculosis detected through whole-genome sequencing. The duplications occur in strains belonging to both M. tuberculosis lineage 2 and 4, and are thus not limited to Beijing strains. The duplications occur in both drug-resistant and drug susceptible strains. The duplicated regions also have substantially different boundaries in different strains, indicating different originating duplication events. We further identify a smaller segmental duplication of a different genomic region of a lab strain of H37Rv. The presence of multiple independent duplications of the same genomic region suggests either instability in this region, a selective advantage conferred by the duplication, or both. The identified duplications suggest that large-scale gene duplication may be more common in M. tuberculosis than previously considere

    Moderation of antipsychotic-induced weight gain by energy balance gene variants in the RUPP autism network risperidone studies.

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    Second-generation antipsychotic exposure, in both children and adults, carries significant risk for excessive weight gain that varies widely across individuals. We queried common variation in key energy balance genes (FTO, MC4R, LEP, CNR1, FAAH) for their association with weight gain during the initial 8 weeks in the two NIMH Research Units on Pediatric Psychopharmacology Autism Network trials (N=225) of risperidone for treatment of irritability in children/adolescents aged 4-17 years with autism spectrum disorders. Variants in the cannabinoid receptor (CNR)-1 promoter (P=1.0 × 10(-6)), CNR1 (P=9.6 × 10(-5)) and the leptin (LEP) promoter (P=1.4 × 10(-4)) conferred robust-independent risks for weight gain. A model combining these three variants was highly significant (P=1.3 × 10(-9)) with a 0.85 effect size between lowest and highest risk groups. All results survived correction for multiple testing and were not dependent on dose, plasma level or ethnicity. We found no evidence for association with a reported functional variant in the endocannabinoid metabolic enzyme, fatty acid amide hydrolase, whereas body mass index-associated single-nucleotide polymorphisms in FTO and MC4R showed only trend associations. These data suggest a substantial genetic contribution of common variants in energy balance regulatory genes to individual antipsychotic-associated weight gain in children and adolescents, which supersedes findings from prior adult studies. The effects are robust enough to be detected after only 8 weeks and are more prominent in this largely treatment naive population. This study highlights compelling directions for further exploration of the pharmacogenetic basis of this concerning multifactorial adverse event
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