10,277 research outputs found
Income Rank and Upward Comparisons
Many studies have argued that relative income predicts individual well-being. More recently, it has been suggested that the relative rank of an individual’s income, rather than how that income compares to a mean or reference income, is important. Here the relative rank hypothesis is examined along with the additional hypothesis that individuals compare their incomes predominantly with those of slightly higher earners. A study of over 12,000 British adults using the British Household Panel Survey (a) confirms the importance of rank and (b) finds evidence that individuals compare upwards and to those most similar. This paper appears to be the first to show in fixed effect well-being equations that the influence of rank is more important than the influence of relative pay.Rank ; social comparison ; life satisfaction ; relative income ; BHPS
Developing a common understanding of a teacher competency framework through video analysis : experiences of Victorian regional independent middle school teachers
This study was deliberately focussed upon the careful examination of a model of professional learning for Middle School teachers, which has at its core, a Teaching and Learning Framework depicting essential elements of effective teaching practice. Set within the context of Middle School classrooms in a Regional Independent school, the intent was to research the impact of the framework on the professional learning of a group of teachers. Research was also undertaken to investigate the effectiveness of feedback and analysis structured around the framework, using video recordings taken from classroom observations.
A group of eight Middle School teachers participated actively in the study to determine how the use of video-stimulated reflective processes might affect improvements in their practice and professional learning. Professional learning opportunities were examined and explored in termsof the impact of the observation and feedback cycle on individual teacher’s progress and against rubric levels within the framework.
At a time when the issue of the tenuous links between professional learning and school improvement is at the forefront of the educational agenda in schools and school systems, it is of significant importance to be able to reflect on a range of models designed to improve teaching, and in turn student learning outcomes in schools. The Teaching and Learning Framework including its subsequent feedback and professional learning processes investigated within this study served to add valuable perspectives to these links
Energy Dependence of Scattering Ground State Polar Molecules
We explore the total cross section of ground state polar molecules in an
electric field at various energies, focusing on RbCs and RbK. An external
electric field polarizes the molecules and induces strong dipolar interactions
leading to non-zero partial waves contributing to the scattering even as the
collision energy goes to zero. This results in the need to compute scattering
problems with many different values of total M to converge the total cross
section. An accurate and efficient approximate total cross section is
introduced and used to study the low field temperature dependence. To
understand the scattering of the polar molecules we compare a semi-classical
cross section with quantum unitarity limit. This comparison leads to the
ability to characterize the scattering based on the value of the electric field
and the collision energy.Comment: Accepted PRA, 10 pages, 5 figure
Trade-offs between fisheries and the conservation of ecosystem function are defined by management strategy
Efforts to conserve marine biodiversity must move beyond conserving individual species within protected areas and seek to preserve the functional roles that species perform in ecosystems across seascapes. For instance, herbivorous and predatory (including invertebrate-feeding) fish are critical for maintaining coralreef habitat and the diversity of dependent fish assemblages. However, increasing the biomasses of fished species may come at a cost to fisheries. Using coral reefs as an example, we examined critical functional roles and model trade-offs between fishery profits and the spatial extent of functional fish communities. The nature of the trade-off depended on the management scenario: protecting functions in small areas could be achieved with marine reserves at minimal cost to fisheries, whereas reducing fishing effort was a more effective method for protecting functional communities across a seascape. An appropriate choice of management actions can alter the trade-off and, in doing so, ameliorate potential for conflict with resource users
Lessons Learned from a Review of 50 ASR Projects from the United States, England, Australia, India, and Africa
The University of Florida has conducted a significant research program over the last four years investigating various aspects of Aquifer, Storage and Recovery (ASR). One pillar of this research effort was the compilation of ASR field data from around the world. Data and supporting information was compiled for over 50 ASR sites located in the United States, England, Australia, India, and Africa. This field data review was completed with two main objectives. First, the ASR operating data was reviewed to evaluate operational similarities and differences. Second, the ASR field data was reviewed to identify fatal flaws that could be avoided at future ASR projects or lessons learned that could aid existing and future ASR projects. Summary tables were prepared comparing basic site information, such as geologic environment or aquifer transmissivity, and site operational characteristics, such as recharge water quality and geochemical issues. Data from 50 of the ASR sites are reviewed in this article. The data revealed that a majority of the sites have been successful in meeting their project goals and objectives; however, a few of the sites have had considerable problems that have limited their overall feasibility
Human sperm ion channel (dys)function:implications for fertilization
BACKGROUND: Intensive research on sperm ion channels has identified members of several ion channel families in both mouse and human sperm. Gene knock-out studies have unequivocally demonstrated the importance of the calcium and potassium conductances in sperm for fertility. In both species, the calcium current is carried by the highly complex cation channel of sperm (CatSper). In mouse sperm, the potassium current has been conclusively shown to be carried by a channel consisting of the pore forming subunit SLO3 and auxiliary subunit leucine-rich repeat-containing 52 (LRRC52). However, in human sperm it is controversial whether the pore forming subunit of the channel is composed of SLO3 and/or SLO1. Deciphering the role of the proton-specific Hv1 channel is more challenging as it is only expressed in human sperm. However, definitive evidence for a role in, and importance for, human fertility can only be determined through studies using clinical samples.OBJECTIVE AND RATIONALE: This review aims to provide insight into the role of sperm ion channels in human fertilization as evidenced from recent studies of sperm from infertile men. We also summarize the key discoveries from mouse ion channel knock-out models and contrast the properties of mouse and human CatSper and potassium currents. We detail the evidence for, and consequences of, defective ion channels in human sperm and discuss hypotheses to explain how defects arise and why affected sperm have impaired fertilization potential.SEARCH METHODS: Relevant studies were identified using PubMed and were limited to ion channels that have been characterized in mouse and human sperm. Additional notable examples from other species are included as appropriate.OUTCOMES: There are now well-documented fundamental differences between the properties of CatSper and potassium channel currents in mouse and human sperm. However, in both species, sperm lacking either channel cannot fertilize in vivo and CatSper-null sperm also fail to fertilize at IVF. Sperm-lacking potassium currents are capable of fertilizing at IVF, albeit at a much lower rate. However, additional complex and heterogeneous ion channel dysfunction has been reported in sperm from infertile men, the causes of which are unknown. Similarly, the nature of the functional impairment of affected patient sperm remains elusive. There are no reports of studies of Hv1 in human sperm from infertile men.WIDER IMPLICATIONS: Recent studies using sperm from infertile men have given new insight and critical evidence supporting the supposition that calcium and potassium conductances are essential for human fertility. However, it should be highlighted that many fundamental questions remain regarding the nature of molecular and functional defects in sperm with dysfunctional ion channels. The development and application of advanced technologies remains a necessity to progress basic and clinical research in this area, with the aim of providing effective screening methodologies to identify and develop treatments for affected men in order to help prevent failed ART cycles. Conversely, development of drugs that block calcium and/or potassium conductances in sperm is a plausible strategy for producing sperm-specific contraceptives.</p
Keck Speckle Imaging of the White Dwarf G29-38: No Brown Dwarf Companion Detected
The white dwarf Giclas 29-38 has attracted much attention due to its large
infrared excess and the suggestion that excess might be due to a companion
brown dwarf. We observed this object using speckle interferometry at the Keck
telescope, obtaining diffraction-limited resolution (55 milliarcseconds) at K
band, and found it unresolved. Assuming the entire K band excess is due to a
single point-like companion, we place an upper limit on the binary separation
of 30 milliarcseconds, or 0.42 AU at the star's distance of 14.1 pc. This
result, combined with astroseismological data and other images of G29-38,
supports the hypothesis that the source of the near-infrared excess is not a
cool companion but a dust cloud.Comment: 7 pages, 2 figure
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