9,638 research outputs found
Gender Differences in K-12 Education: What Indicators Are Important?
Although gender differences have been identified in scholarly research, there is little state reporting of indicators by gender. The purpose of this paper is to identify the gender gaps in K-12 education that have been reported in the literature, to discuss how and when these gaps manifest themselves, and to recommend which of the educational performance indicators should be reported by gender in Georgia. Ultimately, the purpose of reporting indicators by gender is to aid in the efforts to close gender gaps in education.A review of the literature reveals that gender gaps exist at both empirical and experiential levels. Empirically, gaps exist in math, science, and reading proficiency scores, as well as in course enrollment in higher level math and science and graduation rates. Experientially, gaps exist in self esteem levels, personal perceptions of ability, teacher interaction with students, as well as in the advice and opportunities that are afforded students. While studies show that girls and boys start kindergarten on a generally equal footing, by grade twelve girls are generally in a lower academic position than their male counterparts, particularly in the areas of math and science. Research shows that the most critical age for the development of gender gaps is early adolescence, particularly grade seven in which girls= educational performance in math and science begins to plummet.Based on the research and data reported in this paper, the following indicators are recommended to be reported by gender. They are separated into indicators that are currently available by gender, and indicators that are recommended to be reported by gender in the future
Phase transition in thermodynamically consistent biochemical oscillators
Biochemical oscillations are ubiquitous in living organisms. In an autonomous
system, not influenced by an external signal, they can only occur out of
equilibrium. We show that they emerge through a generic nonequilibrium phase
transition, with a characteristic qualitative behavior at criticality. The
control parameter is the thermodynamic force, which must be above a certain
threshold for the onset of biochemical oscillations. This critical behavior is
characterized by the thermodynamic flux associated with the thermodynamic
force, its diffusion coefficient, and the stationary distribution of the
oscillating chemical species. We discuss metrics for the precision of
biochemical oscillations by comparing two observables, the Fano factor
associated with the thermodynamic flux and the number of coherent oscillations.
Since the Fano factor can be small even when there are no biochemical
oscillations, we argue that the number of coherent oscillations is more
appropriate to quantify the precision of biochemical oscillations. Our results
are obtained with three thermodynamically consistent versions of known models:
the Brusselator, the activator-inhibitor model, and a model for KaiC
oscillations.Comment: 13 pages, 11 figure
Spacelab Data Processing Facility (SLDPF) quality assurance expert systems development
The Spacelab Data Processing Facility (SLDPF) is an integral part of the Space Shuttle data network for missions that involve attached scientific payloads. Expert system prototypes were developed to aid in the performance of the quality assurance function of the Spacelab and/or Attached Shuttle Payloads processed telemetry data. The Spacelab Input Processing System (SIPS) and the Spacelab Output Processing System (SOPS), two expert systems, were developed to determine their feasibility and potential in the quality assurance of processed telemetry data. The capabilities and performance of these systems are discussed
Understanding the Transition between High School and College Mathematics and Science
Mathematics and science education is gaining increasing recognition as key for the well-being of individuals and society. Accordingly, the transition from high school to college is particularly important to ensure that students are prepared for college mathematics and science. The goal of this study was to understand how high school mathematics and science course-taking related to performance in college. Specifically, the study employed a nonparametric regression method to examine the relationship between high school mathematics and science courses, and academic performance in college mathematics and science courses. The results provide some evidence pertaining to the positive benefits from high school course-taking. Namely, students who completed high school trigonometry and lab-based chemistry tended to earn higher grades in college algebra and general chemistry, respectively. However, there was also evidence that high school coursework in biology and physics did not improve course performance in general biology and college physics beyond standardized test scores. Interestingly, students who completed high school calculus earned better grades in general biology. The implications of the findings are discussed for high school curriculum and alignment in standards between high schools and colleges
Asymptotics of the solutions of the stochastic lattice wave equation
We consider the long time limit theorems for the solutions of a discrete wave
equation with a weak stochastic forcing. The multiplicative noise conserves the
energy and the momentum. We obtain a time-inhomogeneous Ornstein-Uhlenbeck
equation for the limit wave function that holds both for square integrable and
statistically homogeneous initial data. The limit is understood in the
point-wise sense in the former case, and in the weak sense in the latter. On
the other hand, the weak limit for square integrable initial data is
deterministic
Thermal conductivity in harmonic lattices with random collisions
We review recent rigorous mathematical results about the macroscopic
behaviour of harmonic chains with the dynamics perturbed by a random exchange
of velocities between nearest neighbor particles. The random exchange models
the effects of nonlinearities of anharmonic chains and the resulting dynamics
have similar macroscopic behaviour. In particular there is a superdiffusion of
energy for unpinned acoustic chains. The corresponding evolution of the
temperature profile is governed by a fractional heat equation. In non-acoustic
chains we have normal diffusivity, even if momentum is conserved.Comment: Review paper, to appear in the Springer Lecture Notes in Physics
volume "Thermal transport in low dimensions: from statistical physics to
nanoscale heat transfer" (S. Lepri ed.
Renal endothelial dysfunction in acute kidney ischemia reperfusion injury
Acute kidney injury is associated with alterations in vascular tone that contribute to an overall reduction in GFR. Studies in animal models indicate that ischemia triggers alterations in endothelial function that contribute significantly to the overall degree and severity of a kidney injury. Putative mediators of vasoconstriction that may contribute to the initial loss of renal blood flow and GFR are highlighted. In addition, there is discussion of how intrinsic damage to the endothelium impairs homeostatic responses in vascular tone as well as promotes leukocyte adhesion and exacerbating the reduction in renal blood flow. The timing of potential therapies in animal models as they relate to the evolution of AKI, as well as the limitations of such approaches in the clinical setting are discussed. Finally, we discuss how acute kidney injury induces permanent alterations in renal vascular structure. We posit that the cause of the sustained impairment in kidney capillary density results from impaired endothelial growth responses and suggest that this limitation is a primary contributing feature underlying progression of chronic kidney disease
Anti-angiogenic activity of kidney derived endothelial cells
poster abstractThe identification of novel endogenous mediators of angiogenic/vasculogenic processes may provide for novel therapeutic targets to modulate blood vessel growth in disease states, such as cardiovascular disease or cancer. Studies in our lab have shown that blood vessels in kidney have little endogenous regenerative capacity. Kidney derived microvascular endothelial cells (KEC) were isolated from rat kidney or from transgenic mice bearing the temperature sensitive SV40 mutant (and subsequently grown at non-permissive temperature, 37oC). Both rat and mouse KECs manifested significantly reduced growth rates when compared with several commonly used EC lines (rat pulmonary EC, HUVEC and human cord blood colony forming ECs). In 2D matrigel assays, all commonly used ECs faithfully formed characteristic branching structures; while all KECs failed to form stabile branching structures. Time-course analysis of branching activity demonstrated that KEC initially formed primitive branching nodes within 3 hours of culture, but these structures regressed such that no branched structures were observed between 6-12 hours. Co-culture of KECs with any branching competent EC impaired branching dose dependently. When co-cultured with ECFC, labeled KECs incorporated into primitive ECFC branches within the first 3 hours of plating. However, when compared with ECFC branches, ECFC-KEC mixed branches showed a more rapid regression of the branched structures between 12-24 hrs. Interestingly, conditioned media from KEC did not affect branching of competent ECFC. Taken together, these data indicate that KEC have anti-angiogenic activity that may destabilize ECs during angiogenesis. The anti-angiogenic activity requires cell-cell contact, suggesting the possible presence of an angio-inhibitory molecule on the cell surface of KECs. Current and future studies seek to generate additional KEC lines, and will determine if KEC cell fractions mediate the anti-angiogenic effect. In addition, we will seek to determine if KECs mitigate progression of angiogenic dependent tumor formation in vivo
LCC analysis for glued laminated timber components exposed in external
The aim of the experimentation is to characterize the performances of glued laminated timber components exposed to atmospheric agents, in the light of the concept of Life Cycle Cost, particularly emphasized in the Italian new legislation on public works.
In fact, it could be seen that the design of the construction details and the initial characteristics of glue laminated timber components, require a particular attention to avoid errors that may undermine the possibility to perform the structural functions for which, above all, this material it is dedicated.
The experimentation consisted of a series of tests aimed to identify the performance of glued laminated timber beams taken in site, after a work executed some years ago on a theatre built in Roman era, and to compare them with similarly manufactured new elements. The tests performed were thermography, ultrasound, Wood-Pecker penetrometer, mechanical characterization.
The results will be used to begin setting limits and conditions for outdoor use of glue
laminated timber, and assume a reliable life cycle, and consequently identify the most
appropriate maintenance strategy for the LCC
Structure crustale de la marge transformante de Côte-d'Ivoire - Ghana déduite des observations de gravimétrie en mer
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