1,695 research outputs found
KeV Warm Dark Matter and Composite Neutrinos
Elementary keV sterile Dirac neutrinos can be a natural ingredient of the
composite neutrino scenario. For a certain class of composite neutrino
theories, these sterile neutrinos naturally have the appropriate mixing angles
to be resonantly produced warm dark matter (WDM). Alternatively, we show these
sterile neutrinos can be WDM produced by an entropy-diluted thermal freeze-out,
with the necessary entropy production arising not from an out-of-equilibrium
decay, but rather from the confinement of the composite neutrino sector,
provided there is sufficient supercooling.Comment: 12 pages, 2 figures, published versio
Evaluation of the Total Design Method in a survey of Japanese dentists
BACKGROUND: This study assessed the application of the Total Design Method (TDM) in a mail survey of Japanese dentists. The TDM was chosen because survey response rates in Japan are unacceptably low and the TDM had previously been used in a general population survey. METHODS: Four hundred and seventy eight dentist members of the Okayama Medical and Dental Practitioner's Association were surveyed. The nine-page, 27-item questionnaire covered dentist job satisfaction, physical practice, and dentist and patient characteristics. Respondents to the first mailing or the one-week follow-up postcard were defined as early responders; others who responded were late responders. Responder bias was assessed by examining age, gender and training. RESULTS: The overall response rate was 46.7% (223/478). The response rates by follow-up mailing were, 18% after the first mailing, 35.4% after the follow-up postcard, 42.3% after the second mailing, and 46.7% after the third mailing. Respondents did not differ from non-respondents in age or gender, nor were there differences between early and late responders. CONCLUSION: The application of TDM in this survey of Japanese dentists produced lower rates of response than expected from previous Japanese and US studies
Atividade fĂsica, qualidade de vida e depressĂŁo durante a gravidez
This study examines physical activity patterns among women, from pre-pregnancy to the second trimester of pregnancy, and the relationship between physical activity status based on physical activity guidelines and health-related quality of life (HRQoL) and depression over pregnancy. 56 healthy pregnant women self reported physical activity, HRQoL and depression at 10-15 and 19-24 weeks of pregnancy and physical activity before pregnancy. Whereas vigorous leisure physical activity decreased after conception, moderate leisure physical activity and work related physical activity remained stable over time. The prevalence of recommended physical activity was 39.3% and 12.5% in the 1st and 2nd trimesters of pregnancy respectively, and 14.3% pre-pregnancy. From the 1st to the 2nd pregnancy trimester, most
physical HRQoL dimensions scores decreased and only mental component increased, independently
of physical activity status. No changes in mean depression scores were observed. These data suggest
that physical activity patterns change with pregnancy and that physical and mental components
are differentially affected by pregnancy course, independently of physical activity status.Este estudo examina os padrĂ”es de atividade fĂsica antes
da concepção até o segundo trimestre de gravidez
e a relação entre o nĂvel de atividade fĂsica, com base
nas recomendaçÔes de atividade fĂsica, a qualidade de
vida relacionada Ă saĂșde (QVRS) e depressĂŁo ao longo
da gravidez. Cinquenta e seis grĂĄvidas saudĂĄveis reportaram
nĂvel de atividade fĂsica, QVRS e depressĂŁo
às 10-15 e 19-24 semanas de gravidez, além de atividade
fĂsica antes da concepção. Enquanto a atividade
fĂsica vigorosa no lazer diminuiu depois da concepção,
as atividades fĂsicas moderadas no lazer e no trabalho
mantiveram-se estĂĄveis. A prevalĂȘncia de atividade fĂ-
sica recomendada foi de 39,3%, 12,5% e 14,3% antes,
no primeiro e no segundo trimestres de gravidez, respectivamente.
Independentemente do estatuto de atividade
fĂsica, a maior parte dos escores nas dimensĂ”es
fĂsicas da QVRS diminui do primeiro para o segundo
trimestre de gestação, e apenas o componente mental
aumenta. Não se verificaram alteraçÔes nos escores
médios de depressão. Estes dados sugerem que, com a
gravidez, hĂĄ alteração nos padrĂ”es de atividade fĂsica;
alĂ©m disso, os componentes fĂsico e mental sĂŁo diferentemente
afetados pelo curso da gestação, independentemente
do nĂvel de atividade fĂsica
Effects of a mechanical engineering design course on studentsâ motivational features
Diverse learning opportunities and deep engagement are needed to support development of engineering competencies and expertise. Deep engagement evolves from productive and high-quality motivation that derives from both internal and external sources. Motivation to learn is lacking in many fields, like engineering, because it is too often assumed or ignored, rather than explicitly built into course instruction. While the lack of motivation in engineering education is clear in data-like attrition, there is little relevant research that informs the necessary changes for the field. The purpose of this study is to present a systematic approach that explicitly considers motivational elements in engineering courses. First a comprehensive set of motivational characteristics and the interrelationships for productive motivation of mechanical engineering students are identified. Studentsâ motivational characteristics and profiles of change over time are assessed using a multipoint predictive correlational design. This information is then used to strategically redesign motivational elements of a senior-level mechanical engineering design course. The SUCCESS framework has been used to redesign motivational features of the existing course. This paper reports results of the study, including implications for redesign of other engineering courses. Analysis of the data demonstrates the complexity of motivation in the engineering classroom, which includes addressing implicit and explicit, intrinsic and extrinsic, individual and team interaction and instruction. These elements extend not only to direct communication and interactions of instructor with students but into the full scope of the learning environment, peer-to-peer interactions, grading, (a)synchronous activities, face to face, and virtual communications. Key features of engineering studentsâ productive (learning and engagement-related) motivational profiles consisted of clusters of perceptual and experiential variables that were strongly correlated with motivational and learning outcomes. Tracking these factors demonstrated that they changed over time. These changes corresponded to perceptions of instructor and peer interactions, which were amenable to instructional intervention and responsive to social modeling. This study also revealed links among engineering studentsâ perceptions of their field of study, their own development of self-efficacy, and success expectations in both the design course and for their careers. This work revealed important distinctions between engineering studentsâ self-efficacy for, and engagement in, the course generally and for group tasks more specifically. These newly revealed relationships offer the opportunity to improve engineering instruction and the design of dynamic learning environments that support adaptive skill development.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline
Interviews with Irish healthcare workers from different disciplines about palliative care for people with Parkinsonâs disease: a definite role but uncertainty around terminology and timing
Background: An integrated palliative care approach is recommended in all life-limiting diseases, including Parkinsonâs disease (PD). However research shows that people with PD have unmet palliative care needs. The study aimed to explore multidisciplinary healthcare workersâ (HCWs) views on palliative care for people with PD, identifying perceived barriers and facilitators. Methods: A qualitative design was used; data was analysed using Thematic Analysis. Semi-structured interviews were conducted with 30 HCWs, working either with people with PD or in a palliative care setting in Ireland. Results: A number of perceived barriers were evident helping to account for the previously reported unmet palliative care needs in PD. A lack of education about PD and palliative care meant that HCWs were unsure of the appropriateness of referral, and patients and carers werenât equipped with information to seek palliative care. A lack of communication between PD and palliative care specialists was seen to impede collaboration between the disciplines. Uncertainty about the timing of palliative care meant that it was often not introduced until a crisis point, despite the recognised need for early planning due to increased prevalence of dementia. Conclusions: Most HCWs recognised a need for palliative care for people with PD; however several barriers to implementing a palliative care approach in this population need to be addressed. Implications for clinical practice and policy include the need for an integrated model of care, and education for all HCWs, patients, carers, and the public on both the nature of advanced PD, and the potential of palliative care in support of patients and their family members
Properties of Blood, Porphyrins, and Exposure to Legacy and Emerging Persistent Organic Pollutants in Surf Scoters (Melanitta perspicillata) Overwintering on the South Coast of British Columbia, Canada
The surf scoter (Melanitta perspicillata) is a little-studied species of North American sea duck. Estimates suggest it has experienced a precipitous decline in breeding numbers over the latter half of the past century. To investigate the potential role of contaminant uptake and toxicity in the population decline, this study undertook to measure blood chemistry, porphyrin concentrations, EROD, and organic contaminants in mature surf scoters wintering in the Strait of Georgia, BC, Canada. Hepatic organochlorine pesticide, polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofuran, polychlorinated biphenyl (PCB), polybrominated diphenyl ether, and nonylphenol concentrations were relatively low; for example, ÎŁTEQs (toxic equivalents) for PCBs, dioxins, and furans combined ranged from 4.7Â ng/kg wet weight in reference-site (Baynes Sound) birds to 11.4Â ng/kg wet weight in birds from Vancouver Harbour. Nonetheless, elevated EROD activity indicated that birds in Howe Sound were responding to an Ah-receptor-mediated stressor, which was also affecting hematocrit values and possibly vitamin A status. In addition, a low proportion of lymphocytes in individuals across locations in early spring samples was associated with poor body condition. The apparent loss of fitness just prior to the onset of northerly migrations to breeding grounds is of particular concern. Compromised health of mature birds at this point in the season might impact negatively on the productivity and survival of some individuals, particularly those overwintering in Howe Sound
Confined dense circumstellar material surrounding a regular type II supernova
With the advent of new wide-field, high-cadence optical transient surveys, our understanding of the diversity of core-collapse supernovae has grown tremendously in the last decade. However, the pre-supernova evolution of massive stars, which sets the physical backdrop to these violent events, is theoretically not well understood and difficult to probe observationally. Here we report the discovery of the supernova iPTF 13dqy = SN 2013fs a mere âŒ3 h after explosion. Our rapid follow-up observations, which include multiwavelength photometry and extremely early (beginning at âŒ6 h post-explosion) spectra, map the distribution of material in the immediate environment (âČ1015 cm) of the exploding star and establish that it was surrounded by circumstellar material (CSM) that was ejected during the final âŒ1 yr prior to explosion at a high rate, around 10-3 solar masses per year. The complete disappearance of flash-ionized emission lines within the first several days requires that the dense CSM be confined to within âČ1015 cm, consistent with radio non-detections at 70â100 days. The observations indicate that iPTF 13dqy was a regular type II supernova; thus, the finding that the probable red supergiant progenitor of this common explosion ejected material at a highly elevated rate just prior to its demise suggests that pre-supernova instabilities may be common among exploding massive stars. © 2017 Nature Publishing Grou
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