7,007 research outputs found
Taber Vibration Isolator for Vacuum and Cryogenic Applications
We present a procedure for the design and construction of a passive,
multipole, mechanical high-stop vibration isolator. The isolator, consisting of
a stack of metal disks connected by thin wires, attenuates frequencies in the
kilohertz range, and is suited to both vacuum and cryogenic environments. We
derive an approximate analytical model and compare its predictions for the
frequencies of the normal modes to those of a finite element analysis. The
analytical model is exact for the modes involving only motion along and
rotation about the longitudinal axis, and it gives a good approximate
description of the transverse modes. These results show that the high-frequency
behavior of a multi-stage isolator is well characterized by the natural
frequencies of a single stage. From the single-stage frequency formulae, we
derive relationships among the various geometrical parameters of the isolator
to guarantee equal attenuation in all degrees of freedom. We then derive
expressions for the attenuation attainable with a given isolator length, and
find that the most important limiting factor is the elastic limit of the spring
wire material. For our application, which requires attenuations of 250 dB at 1
kHz, our model specifies a six-stage design using brass disks of approximately
2 cm in both radius and thickness, connected by 3 cm steel wires of diameters
ranging from 25 to 75 microns. We describe the construction of this isolator in
detail, and compare measurements of the natural frequencies of a single stage
with calculations from the analytical model and the finite element package. For
translations along and rotations about the longitudinal axes, all three results
are in agreement to within 10% accuracy.Comment: 11 pages, 13 figures, REVTe
Market Response to Two Alternative Packages for U.S. No. 2 Grapefruit
Packages, U.S. No. 2 Grapefruits, Grapefruit, Alternatives, Crop Production/Industries, Food Consumption/Nutrition/Food Safety, Marketing,
A Consumer Test of Citrus Drinks made from Comminuted Whole Citrus Fruit
Consumer, Citrus, Whole Citrus Fruit, Citrus Fruit, Consumer Test, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,
A Consumer Test of Canned Seasoned Salad Tomatoes
Consumer, Canned Tomatoes, Salad Tomatoes, Seasoned Tomatoes, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,
Fermi surface, possible unconventional fermions, and unusually robust resistive critical fields in the chiral-structured superconductor AuBe
The noncentrosymmetric superconductor (NCS) AuBe is investigated using a
variety of thermodynamic and resistive probes in magnetic fields of up to 65~T
and temperatures down to 0.3~K. Despite the polycrystalline nature of the
samples, the observation of a complex series of de Haas-van Alphen (dHvA)
oscillations has allowed the calculated bandstructure for AuBe to be validated.
This permits a variety of BCS parameters describing the superconductivity to be
estimated, despite the complexity of the measured Fermi surface. In addition,
AuBe displays a nonstandard field dependence of the phase of dHvA oscillations
associated with a band thought to host unconventional fermions in this chiral
lattice. This result demonstrates the power of the dHvA effect to establish the
properties of a single band despite the presence of other electronic bands with
a larger density of states, even in polycrystalline samples. In common with
several other NCSs, we find that the resistive upper critical field exceeds
that measured by heat capacity and magnetization by a considerable factor. We
suggest that our data exclude mechanisms for such an effect associated with
disorder, implying that topologically protected superconducting surface states
may be involved
Secretome Analysis of Skeletal Myogenesis Using SILAC and Shotgun Proteomics
Myogenesis, the formation of skeletal muscle, is a multistep event that commences with myoblast proliferation, followed by cell-cycle arrest, and finally the formation of multinucleated myotubes via fusion of mononucleated myoblasts. Each step is orchestrated by well-documented intracellular factors, such as cytoplasmic signalling molecules and nuclear transcription factors. Regardless, the key step in getting a more comprehensive understanding of the regulation of myogenesis is to explore the extracellular factors that are capable of eliciting the downstream intracellular factors. This could further provide valuable insight into the acute cellular response to extrinsic cues in maintaining normal muscle development. In this paper, we survey the intracellular factors that respond to extracellular cues that are responsible for the cascades of events during myogenesis: myoblast proliferation, cell-cycle arrest of myoblasts, and differentiation of myoblasts into myotubes. This focus on extracellular perspective of muscle development illustrates our mass spectrometry-based proteomic approaches to identify differentially expressed secreted factors during skeletal myogenesis
A Prospective Study of Religiousness and Psychological Distress among Female Survivors of Hurricanes Katrina and Rita
This prospective study examined the pathways by which religious involvement affected the postdisaster psychological functioning of women who survived Hurricanes Katrina and Rita. The participants were 386 low-income, predominantly Black, single mothers. The women were enrolled in the study before the hurricane, providing a rare opportunity to document changes in mental health from before to after the storm, and to assess the protective role of religious involvement over time. Results of structural equation modeling indicated that, controlling for level of exposure to the hurricanes, pre-disaster physical health, age, and number of children, predisaster religiousness predicted higher levels of post-disaster (1) social resources and (2) optimism and sense of purpose. The latter, but not the former, was associated with better post-disaster psychological outcome. Mediation analysis confirmed the mediating role of optimism and sense of purpose
A high prevalence of abnormal nutrition parameters found in predialysis end-stage kidney disease: is it a result of uremia or poor eating habits?
Objective To describe the baseline nutritional characteristics of a cohort of end-stage kidney disease (ESKD) patients attending a pre-dialysis clinic. Setting Outpatient clinic of a metropolitan tertiary teaching hospital in Sydney, Australia. Subjects All ESKD patients attending the multidisciplinary pre-dialysis assessment clinic between April 2002 and March 2008. Methods Retrospective analysis of data extracted from the routine initial nutrition assessment records. These included anthropometric and biochemical measures, Subjective Global Assessment, appetite score, presence of symptoms, dietary energy, protein, and other macro- and micronutrient intakes. Results Of the 210 patients assessed, 60.5% were male; mean age was 65.7 ± 13.6 years with a mean glomerular filtration rate of 17.3 ± 6.5 mL/min/1.73 m2; 17.1% and 62.4% were underweight (body mass index /m2) and overweight or obese (BMI ≥26 kg/m2), respectively; 40.5% were rated as malnourished (Subjective Global Assessment scores B and C) with 19.0% overweight/obese and malnourished. Energy and protein intakes correlated positively with glomerular filtration rate, with r = 0.17, P = .01, and r = 0.29, P \u3c .0001 respectively. Mean energy and protein intakes were 23.7 ± 6.7 kcal/kg IBW/day and 1.18 ± 0.42 g/kg IBW/day, with 62.6% and 13.1% not meeting the recommended intake, respectively. The positive predictive values (95%CI) of self-rated appetite score for energy and protein were 0.41 (0.36-0.45) and 0.92 (0.88-0.95), respectively, indicating subjective rating of a good appetite was associated with adequate protein but not energy intake. Fifty-one percent of the patients experienced the symptoms, whereas 17.5% of the patients self-imposed a dietary regimen inappropriately due to beliefs on dietary needs in ESKD. Suboptimal nutrient intakes were observed, including vitamin B2 (41.2%), vitamin E (61.8%), folate (67.6.2%), vitamin D (100.0%), and zinc (64.2%). Conclusion Patients presented to the pre-dialysis assessment clinic with abnormal nutrition parameters associated with decreased renal function, symptoms burden, and poor dietary intake. This clinic may provide an opportunity to optimize the nutritional status of ESKD patients in the pre-dialysis period
Accounting for the association of family conflict and heavy alcohol use among adolescent girls: the role of depressed mood
Objective: Heavy alcohol use increases dramatically at age 14, and there is emerging cross-sectional evidence that when girls experience family conflict at younger ages (11-13 years) the risk of alcohol use and misuse is high. This study evaluated the role of family conflict and subsequent depressed mood in predicting heavy alcohol use among adolescent girls. Method: This was a three-wave longitudinal study with annual assessments (modal ages 12, 13, and 14 years). The participants (N = 886, 57% female) were from 12 metropolitan schools in Victoria, Australia, and participants completed questionnaires during school class time. The key measures were based on the Communities That Care Youth Survey and included family conflict (Wave 1), depressed mood (Wave 2), and heavy alcohol use (Wave 3). Control variables included school commitment, number of peers who consumed alcohol, whether parents were living together, and ethnic background. Results: With all controls in the model, depressed mood at Wave 2 was predicted by family conflict at Wave 1. The interaction of family conflict with gender was significant, with girls showing a stronger association of family conflict and depressed mood. Depressed mood at Wave 2 predicted heavy alcohol use at Wave 3. Conclusions: Girls may be especially vulnerable to family conflict, and subsequent depressed mood increases the risk of heavy alcohol use. The results support the need for gender-sensitive family-oriented prevention programs delivered in late childhood and early adolescence. (J. Stud. Alcohol Drugs, 74, 396-405, 2013
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