911 research outputs found
Study of water recovery and solid waste processing for aerospace and domestic applications. Volume 2: Final report
The manner in which current and advanced technology can be applied to develop practical solutions to existing and emerging water supply and waste disposal problems is evaluated. An overview of water resource factors as they affect new community planning, and requirements imposed on residential waste treatment systems are presented. The results of equipment surveys contain information describing: commercially available devices and appliances designed to conserve water; devices and techniques for monitoring water quality and controlling back contamination; and advanced water and waste processing equipment. System concepts are developed and compared on the basis of current and projected costs. Economic evaluations are based on community populations of from 2,000 to 250,000. The most promising system concept is defined in sufficient depth to initiate detailed design
Decay of Quantum Accelerator Modes
Experimentally observable Quantum Accelerator Modes are used as a test case
for the study of some general aspects of quantum decay from classical stable
islands immersed in a chaotic sea. The modes are shown to correspond to
metastable states, analogous to the Wannier-Stark resonances. Different regimes
of tunneling, marked by different quantitative dependence of the lifetimes on
1/hbar, are identified, depending on the resolution of KAM substructures that
is achieved on the scale of hbar. The theory of Resonance Assisted Tunneling
introduced by Brodier, Schlagheck, and Ullmo [9], is revisited, and found to
well describe decay whenever applicable.Comment: 16 pages, 11 encapsulated postscript figures (figures with a better
resolution are available upon request to the authors); added reference for
section
Arnol'd Tongues and Quantum Accelerator Modes
The stable periodic orbits of an area-preserving map on the 2-torus, which is
formally a variant of the Standard Map, have been shown to explain the quantum
accelerator modes that were discovered in experiments with laser-cooled atoms.
We show that their parametric dependence exhibits Arnol'd-like tongues and
perform a perturbative analysis of such structures. We thus explain the
arithmetical organisation of the accelerator modes and discuss experimental
implications thereof.Comment: 20 pages, 6 encapsulated postscript figure
A Classic Model in a Low Fertility Context: The Proximate Determinants of Fertility in South Korea and the United States
John Bongaarts' proximate determinants model of fertility has accounted for over 90 percent of variation in the total fertility rate (TFR) of primarily developing nations and historical populations. Recently, dramatically low fertility rates across the globe have raised questions regarding whether this model could be applied to exclusively below-replacement nations. This study follows Knodel, Chamratrithirong, and Debavalya's 1987 analysis of fertility decline in Thailand by conducting in-depth case studies of the proximate determinants in two low fertility countries over time: South Korea, where fertility is well below the level of replacement, and the United States, where fertility has hovered around replacement level for many years. Then, the fertility-inhibiting effect of the proximate determinants is assessed by comparing the quantitative index representing each determinant measured in the 1960s/1970s with its measurement in the 2000s. For both years, I consider the fertility level that would prevail in the determinant's presence as well as the level that would exist in its absence. Finally, I use each of the indices to calculate the TFR and assess how the strength of the model varies over time in the two countries.
Ultimately, results indicate that the proximate determinants model does not offer a clean picture of the fertility level in either South Korea or the United States; when trends uncovered by the case studies are compared to the results of the quantitative analysis, a number of inconsistencies are revealed. This suggests that certain components in the model may need to be respecified for more effective application in low-fertility contexts. However, that is not to say that it offers no insight into fertility at all or that it is no longer a useful tool. On the contrary, it is shown that the proximate determinants model holds a lot of potential for analysis in low-fertility nations. The implications of these results, as well as the need for improvements in international data collection efforts, are also discussed
The Impact of Body Image Preoccupation on College Adjustment
Faculty Research Day 2018: Graduate Student Poster Honorable MentionThe physical and psychological adjustment to college is a often a disorienting time for students. Upon entering college, students are met with a new set of societal, personal, and academic expectations that decide the degree to which they are able to adapt to their new lives (Tinto, 1993). Given the taxing mental demands associated with the college transition, as well as the increasing prevalence of mental illnesses among college students (Duarte, Ferreira, Trindade, & Pinto-Gouveia, 2015; Hunt & Eisenberg, 2010), extensive research has examined the many psychological components that can effect studentsâ college experiences. Yet, despite the extensive literatures centering around body image preoccupation and college studentsâ psychological health/adjustment to college, there have been no studies that assess body image alongside college adjustment. The present study aims to fill this gap in the literature by examining the association of body image preoccupation and studentsâ adjustment to college
[OP.2D.05] RELATIONSHIP OF OXIDATIVE STRESS WITH CARDIAC HYPERTROPHY IN HYPERTENSIVE PATIENTS
OBJECTIVE: Left ventricular hypertrophy is common in hypertensive patients. In these subjects increased oxidative stress has been observed. Our aim was to evaluate the association of biomarkers of both oxidative stress and inflammation with markers of cardiovascular damage in a large group of hypertensives with different stages of renal function.
DESIGN AND METHOD: In 517 hypertensives we analyzed left ventricular mass indexed for body surface area, and we assayed plasma levels of 8-isoprostaglandin F2alpha and high sensitivity C reactive protein.
RESULTS: Multivariate analysis carried out considering left ventricular mass as dependent variable, and including 8-isoprostaglandin F2alpha, high sensitivity C reactive protein, age, sex, body mass index, estimated glomerular filtration rate, serum glucose, (log)triglycerides, hemoglobin, pulse pressure or systolic blood pressure, mean or diastolic blood pressure, and antihypertensive treatment showed that in hypertensives plasma levels of 8-isoprostaglandin F2alpha were correlated with left ventricular mass (beta=0.269, p\u200a<\u200a0.0001).The bivariate relationship of left ventricular mass with 8-isoprostaglandin F2alpha in hypertensives with estimated glomerular filtration rate higher and lower than 60\u200aml/min/1.73m2 was also calculated separately, demonstrating no significant differences in both correlations coefficients and slopes of the regression lines (r\u200a=\u200a0.254, p\u200a<\u200a0.001 and r\u200a=\u200a0.226, p\u200a<\u200a0.002; respectively).In the overall group, receiver operating characteristic curves showed that 8-isoprostaglandin F2alpha and high sensitivity C reactive protein were predictors of left ventricular hypertrophy, p\u200a<\u200a0.0001.
CONCLUSIONS: To the best of our knowledge, this is the first demonstration that in hypertensives oxidative stress is correlated to left ventricular hypertrophy independently of other confounding factors. Oxidative stress might participate in the development of hypertensive cardiac hypertrophy
The presence of dominant follicles and corpora lutea does not perturb response to controlled ovarian stimulation in random start protocols
The advent of random start protocols to shorten the time needed to store oocytes in women with malignancies has represented an important improvement in the field of fertility preservation. However, Randomized Controlled Trials are difficult to implement in this area and available evidence that supports this approach remains modest. To shed more light on this issue, we compared the follicular development between the ovary carrying the dominant follicle or the corpus luteum and the contralateral resting ovary in 90 women who underwent random start controlled ovarian stimulation (COS). In fact, ovarian response did not differ between the two ovaries. Subgroup analyses according to the phase of the cycle at the initiation of COS, the type of malignancy, the use of letrozole and the magnitude of the ovarian response did not allow to identify any condition showing a difference in the follicular response between the active and the resting ovaries. In conclusion, follicular growth does not seem to be perturbed by the presence of a dominant follicle or a corpus luteum
Fractal fluctuations in quantum integrable scattering
We theoretically and numerically demonstrate that completely integrable
scattering processes may exhibit fractal transmission fluctuations, due to
typical spectral properties of integrable systems.
Similar properties also occur with scattering processes in the presence of
strong dynamical localization, thus explaining recent numerical observations of
fractality in the latter class of systems.Comment: revtex, 4 pages, 3 eps figure
Optimizing aesthetic outcomes after goldilocks mastectomy: A new method of nipple reconstruction
On the spacing distribution of the Riemann zeros: corrections to the asymptotic result
It has been conjectured that the statistical properties of zeros of the
Riemann zeta function near z = 1/2 + \ui E tend, as , to the
distribution of eigenvalues of large random matrices from the Unitary Ensemble.
At finite numerical results show that the nearest-neighbour spacing
distribution presents deviations with respect to the conjectured asymptotic
form. We give here arguments indicating that to leading order these deviations
are the same as those of unitary random matrices of finite dimension , where is a well
defined constant.Comment: 9 pages, 3 figure
- âŠ