1,053 research outputs found
Observation of a possible superflare on Proxima Centauri
We report the observation on UT 2017 July 1 of an unusually powerful flare detected in near-infrared continuum photometry of Proxima Centauri. During a campaign monitoring the star for possible exoplanet transits, we identified an increase in Sloan i' flux leading to an observed peak at BJD 2457935.996 that was at least 10 per cent over pre-flare flux in this band. It was followed by a two-component rapid decline in the first 100 s that became a slower exponential decay with time constant of 1350 s. A smaller flare event 1300 s after the first added an incremental peak flux increase of 1 per cent of pre-flare flux. Since the onset of the flare was not fully time resolved at a cadence of 62 s, its actual peak value is unknown but greater than the time average over a single exposure of 20 s. The i' band is representative of broad optical and near-IR continuum flux over which the integrated energy of the flare is 100 times the stellar luminosity. This meets the criteria that established the concept of superflares on similar stars. The resulting implied ultraviolet flux and space weather could have had an extreme effect on the atmospheres of planets within the star's otherwise habitable zone
Evaluating Pre-Service Teacher Workforce: Environmental Health Knowledge, Attitude, and Behavior
Abstract
Research has shown that personal health behaviors and actions established early in life are often carried through adulthood. Thus, working with children to increase environmental health literacy may improve the environmental health literacy of future adults, potentially improving the health of the Nation. Given the amount of time children spend in school, this setting could be an ideal place to address environmental health with children. According to social cognitive theory, observation is one way in which learning takes place. Consequently, the environmental behaviors and attitudes modeled by teachers would likely impact the environmental behaviors and attitudes learned by students. A research study including 101 pre-service teachers from a large Midwestern university was conducted to determine participants’ knowledge, attitudes, and behaviors regarding environmental health. Results indicated major deficiencies in basic knowledge as well as many unfavorable environmental behaviors. On average, participants answered only 49.7% of knowledge items correctly. Less than half (46.0%) recycle bottles or cans “often” or “almost always.” Given these results, pre-service teachers are likely ill-prepared to address environmental health literacy in their classrooms. Teacher education programs need to address this deficiency in pre-service teachers through the implementation of new courses focused on environmental health or the redesign of current courses to include environmental health content
A twin-mirrored galvanometer laser light sheet generator
A galvanometer mirror-based laser light sheet system has been developed for use in the Basic Aerodynamics Research Tunnel at NASA Langley. This system generates and positions single or multiple light sheets over aeronautical research models being tested in the low speed tunnel. This report describes a twin mirrored galvanometer laser light sheet generator and shows typical light sheet arrangements in use. With this system, illumination of smoke entrained in the flow over a delta wing model reveals the vortical flow produced by the separation of the flow at the leading edge of the model. The light sheet system has proven to be very adaptable and easy to use in sizing and positioning light sheets in wind tunnel applications
Cross-cultural effects of color, but not morphological masculinity, on perceived attractiveness of men's faces
This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 ElsevierMuch attractiveness research has focused on face shape. The role of masculinity (which for adults is thought to be a relatively stable shape cue to developmental testosterone levels) in male facial attractiveness has been examined, with mixed results. Recent work on the perception of skin color (a more variable cue to current health status) indicates that increased skin redness, yellowness, and lightness enhance apparent health. It has been suggested that stable cues such as masculinity may be less important to attractiveness judgments than short-term, more variable health cues. We examined associations between male facial attractiveness, masculinity, and skin color in African and Caucasian populations. Masculinity was not found to be associated with attractiveness in either ethnic group. However, skin color was found to be an important predictor of attractiveness judgments, particularly for own-ethnicity faces. Our results suggest that more plastic health cues, such as skin color, are more important than developmental cues such as masculinity. Further, unfamiliarity with natural skin color variation in other ethnic groups may limit observers' ability to utilize these color cues
Healthy ageing and binding features in working memory: measurement issues and potential boundary conditions
Accurate memory for an object or event requires that multiple diverse features are
bound together and retained as an integrated representation. There is overwhelming
evidence that healthy ageing is accompanied by an associative deficit in that older
adults struggle to remember relations between items above any deficit exhibited in
remembering the items themselves. However, the effect of age on the ability to
bind features within novel objects (for example, their colour and shape) and retain
correct conjunctions over brief intervals is less clear. The relatively small body of
work that exists on this topic to-date has suggested no additional working memory
impairment for conjunctions of features beyond a general age-related impairment in
the ability to temporarily retain features. This is in stark contrast to the feature
binding deficit observed in the early stages of Alzheimer’s disease. Nevertheless,
there have been reports of age-related feature binding deficits in working memory
under specific circumstances. Thus a major focus of the present work was to assess
these potential boundary conditions.
The change detection paradigm was used throughout this work to examine age-differences in visual working memory. Despite the popularity of this task important
issues regarding the way in which working memory is probed have been left unaddressed.
Chapter 2 reports three experiments with younger adults comparing two
methods of testing recognition memory for features or conjunctions. Contrary to an
influential study in the field, it appears that processing multiple items at test does
not differentially impact on participants’ ability to detect binding changes.
Chapters 3, 4, and 5 report a series of experiments motivated by previous findings
of specific age-related feature binding deficits. These experiments, improving on previous methodology where possible, demonstrate that increasing the amount of time
for which items can be studied (Chapter 3) or mixing feature-conjunction changes in
trial-blocks with more salient changes to individual features (Chapters 4 and 5) does
not differentially impact on healthy older adults’ ability to detect binding changes.
Rather, the argument is made that specific procedural aspects of previous work led
to the appearance of deficits that do not generalise. Chapter 5 also addresses the
suggestion that healthy ageing specifically affects the retention of item-location conjunctions.
The existing evidence for this claim is reviewed, and found wanting, and
new data are presented providing evidence against it.
To follow-up on the absence of a deficit for simple feature conjunctions, Chapter 6
contrasts two theoretically distinct binding mechanisms: one for features intrinsic
to an object and another for extrinsic, contextual features. Preliminary evidence is
reported that the cost associated with retaining pairings of features is specifically
pronounced for older adults when the features are extrinsic to each other.
In an attempt to separate out the contribution of working memory capacity
and lapses of attention to age-differences in overall task performance, Chapter 7
reports the results of an exploratory analysis using processing models developed
in Chapter 2. Analysis of two data sets from Chapters 4 and 5 demonstrates that
lapses of attention make an important contribution to differences in change detection
performance.
Chapter 8 returns to the issue of measurement in assessing the evidence for
specific age-related deficits. Simulations demonstrate that the choice of outcome
measure can greatly affect conclusions regarding age-group by condition interactions,
suggesting that some previous findings of such interactions in the literature may have
been more apparent than real.
In closing the General Discussion relates the present work to current theory
regarding feature binding in visual working memory and to the wider literature on
binding deficits in healthy and pathological ageing
Healthy aging and visual working memory:The effect of mixing feature and conjunction changes
It has been suggested that an age-related decrease in the ability to bind and retain conjunctions of features may account for some of the pronounced decline of visual working memory across the adult life-span. So far the evidence for this proposal has been mixed with some suggesting a specific deficit in binding to location, while the retention of surface feature conjunctions (e.g. color-shape) appears to remain largely intact. The present experiments follow up on the results of an earlier study, which found that older adults were specifically poor at detecting conjunction changes when they were mixed with trials containing changes to individual features, relative to when these trials were blocked (Cowan et al., 2006, Dev. Psychol., 42, pp. 1089). Using stimuli defined by conjunctions of color and shape (Experiment 1), and color and location (Experiment 2) we find no evidence that older adults are less accurate at detecting binding changes when trial types are mixed. Further, analysis of estimates of discriminability provides substantial-to-strong evidence against this suggestion. We discuss these findings in relation to previous studies addressing the same question and suggest that much of the evidence for specific age-related VWM binding deficits is not as strong as it first appears
Analysing and supporting spare parts and maintenance supply chains for handpumps in rural DR Congo
This paper presents findings from a study of spare parts and maintenance supply chains for handpumps in rural areas of the Democratic Republic of the Congo (DRC) in 2014 by the consultants Absolute Options for Concern Worldwide, and the steps taken by Concern towards implementing some of the key recommendations as part of the DRC WASH Consortium. The analysis and findings are relevant for other actors working on rural water supply. Key emerging issues are the role of international NGOs and donors in supporting supply chain development through more local procurement; the feasible level of professionalization of rural water management; and how INGOs can play a facilitation role in linking local actors to discuss and address these challenges
Tackling concentrated worklessness: integrating governance and policy across and within spatial scales
Spatial concentrations of worklessness remained a key characteristic of labour markets in advanced industrial economies, even during the period of decline in aggregate levels of unemployment and economic inactivity evident from the late 1990s to the economic downturn in 2008. The failure of certain localities to benefit from wider improvements in regional and national labour markets points to a lack of effectiveness in adopted policy approaches, not least in relation to the governance arrangements and policy delivery mechanisms that seek to integrate residents of deprived areas into wider local labour markets. Through analysis of practice in the British context, we explore the difficulties of integrating economic and social policy agendas within and across spatial scales to tackle problems of concentrated worklessness. We present analysis of a number of selected case studies aimed at reducing localised worklessness and identify the possibilities and constraints for effective action given existing governance arrangements and policy priorities to promote economic competitiveness and inclusion
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