5,910 research outputs found

    Properties of the Power Envelope for Tests Against Both Stationary and Explosive Alternatives: The Effect of Trends

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    This paper details a precise analytic e¤ect that inclusion of a linear trend has on the power of Neyman-Pearson point optimal unit root tests and thence the power envelope. Both stationary and explosive alternatives are considered. The envelope can be characterized by probabilities for two, related, sums of chi-square random variables. A stochastic expansion, in powers of the local-to-unity parameter, of the di¤erence between these loses its leading term when a linear trend is included. This implies that the power envelope converges to size at a faster rate, which can then be exploited to prove that the power envelope must necessarily be lower. This e¤ect is shown to be, analytically, greater asymptotically than in small samples and numerically far greater for explosive than for stationary alternatives. Only a linear trend has a speci…c rate e¤ect on the power envelope, however other deterministic variables will have some e¤ect. The methods of the paper lead to a simple direct measure of this e¤ect which is then informative about power, in practice

    Interventions to improve the sleep quality of adults with personality disorder: a systematic review

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    Poor quality sleep is common for people who have a diagnosis of personality disorder (PD). Core cognitive and behavioral features of PD may cause and perpetuate poor sleep, but to date, no review has collated the evidence on the efficacy of interventions to improve sleep quality for people with PD. Structured searches for interventional studies among adults with PD and reporting validated measures of sleep quality were conducted up to November 2022 in multiple databases. Single-case reports were excluded. Study quality was assessed with standardized risk of bias tools. Unreported data was sought systematically from authors. This review was pre-registered with an international prospective register of systematic reviews (PROSPERO) (CRD42021282105). Of the 3503 identified studies, nine met inclusion criteria, representing a range of psychological, pharmaceutical, and other interventions and outcome measures. Meta-analytic methods were not feasible because of the serious risk of bias in all studies, and results were therefore synthesized narratively. There is limited and low-quality evidence of the effects of a variety of interventions to improve the sleep quality of people living with PD. Further research might consider specifically including people diagnosed with PD in trials of sleep interventions and using sleep outcome measures in trials of established PD treatments

    Friction and wear behavior of glasses and ceramics

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    Adhesion, friction, and wear behavior of glasses and ionic solids are reviewed. These materials are shown to behave in a manner similar to other solids with respect to adhesion. Their friction characteristics are shown to be sensitive to environmental constituents and surface films. This sensitivity can be related to a reduction in adhesive bonding and the changes in surficial mechanical behavior associated with Rehbinder and Joffe effects. Both friction and wear properties of ionic crystalline solids are highly anisotropic. With metals in contact with ionic solids the fracture strength of the ionic solid and the shear strength in the metal and those properties that determine these will dictate which of the materials undergoes adhesive wear. The chemical activity of the metal plays an important role in the nature and strength of the adhesive interfacial bond that develops between the metal and a glass or ionic solid

    Bridging flavour violation and leptogenesis in SU(3) family models

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    We reconsider basic, in the sense of minimal field content, Pati-Salam x SU(3) family models which make use of the Type I see-saw mechanism to reproduce the observed mixing and mass spectrum in the neutrino sector. The goal of this is to achieve the observed baryon asymmetry through the thermal decay of the lightest right-handed neutrino and at the same time to be consistent with the expected experimental lepton flavour violation sensitivity. This kind of models have been previously considered but it was not possible to achieve a compatibility among all of the ingredients mentioned above. We describe then how different SU(3) messengers, the heavy fields that decouple and produce the right form of the Yukawa couplings together with the scalars breaking the SU(3) symmetry, can lead to different Yukawa couplings. This in turn implies different consequences for flavour violation couplings and conditions for realizing the right amount of baryon asymmetry through the decay of the lightest right-handed neutrino. Also a highlight of the present work is a new fit of the Yukawa textures traditionally embedded in SU(3) family models.Comment: 26 pages, 5 figures, Some typos correcte

    Masculinity as Governance: police, public service and the embodiment of authority, c. 1700-1850

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    About the book: Public Men offers an introduction to an exciting new field: the history of masculinities in the political domain and will be essential reading for students and specialists alike with interests in gender or political culture. By building upon new work on gender and political culture, these new case studies explore the gendering of the political domain and the masculinities of the men who have historically dominated it. As such, Public Men is a major contribution to our understanding of the history of Britain between the Eighteenth and the Twentieth centuries

    Examining the Relationships among the Coaching Climate, Life Skills Development and Well-Being in Sport

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    Using Benson and Saito's framework for positive youth development, we investigated the relationships between the coaching climate, young people's perceived life skills development within sport, and their psychological well-being. British youth sport participants (N=326, Mage=13.81, range=11–18 years) completed a survey assessing the coaching climate, participants' perceived life skills development (teamwork, goal setting, time management, emotional skills, interpersonal communication, social skills, leadership, and problem solving and decision making) and psychological well-being (self-esteem, positive affect, and satisfaction with life). In all analyses, the coaching climate was positively related to young peoples' perceived development of life skills within sport and their psychological well-being. Total life skills development (a summative score of all eight life skills scores) was positively related to all three psychological well-being indicators – providing support for the "pile-up" effect – and partially mediated the relationships between the coaching climate and participants' psychological well-being. Interpretation of the results indicated that coaches should foster the development of multiple life skills in youth sport participants, as they are associated with participants' psychological well-being. One way this can be achieved is through autonomy-supportive coaching behaviours

    'It is like a tomato stall where someone can pick what he likes': structure and practices of female sex work in Kampala, Uganda.

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    BACKGROUND: Effective interventions among female sex workers require a thorough knowledge of the context of local sex industries. We explore the organisation of female sex work in a low socio-economic setting in Kampala, Uganda. METHODS: We conducted a qualitative study with 101 participants selected from an epidemiological cohort of 1027 women at high risk of HIV in Kampala. Repeat in-depth life history and work practice interviews were conducted from March 2010 to June 2011. Context specific factors of female sex workers' day-to-day lives were captured. Reported themes were identified and categorised inductively. RESULTS: Of the 101 women, 58 were active self-identified sex workers operating in different locations within the area of study and nine had quit sex work. This paper focuses on these 67 women who gave information about their involvement in sex work. The majority had not gone beyond primary level of education and all had at least one child. Thirty one voluntarily disclosed that they were HIV-positive. Common sex work locations were streets/roadsides, bars and night clubs. Typically sex occurred in lodges near bars/night clubs, dark alleyways or car parking lots. Overall, women experienced sex work-related challenges at their work locations but these were more apparent in outdoor settings. These settings exposed women to violence, visibility to police, a stigmatising public as well as competition for clients, while bars provided some protection from these challenges. Older sex workers tended to prefer bars while the younger ones were mostly based on the streets. Alcohol consumption was a feature in all locations and women said it gave them courage and helped them to withstand the night chill. Condom use was determined by clients' willingness, a woman's level of sobriety or price offered. CONCLUSIONS: Sex work operates across a variety of locations in the study area in Kampala, with each presenting different strategies and challenges for those operating there. Risky practices are present in all locations although they are higher on the streets compared to other locations. Location specific interventions are required to address the complex challenges in sex work environments

    Dynein structure and power stroke

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    Dynein ATPases are microtubule motors that are critical to diverse processes such as vesicle transport and the beating of sperm tails; however, their mechanism of force generation is unknown. Each dynein comprises a head, from which a stalk and a stem emerge. Here we use electron microscopy and image processing to reveal new structural details of dynein c, an isoform from Chlamydomonas reinhardtii flagella, at the start and end of its power stroke. Both stem and stalk are flexible, and the stem connects to the head by means of a linker approximately 10 nm long that we propose lies across the head. With both ADP and vanadate bound, the stem and stalk emerge from the head 10 nm apart. However, without nucleotide they emerge much closer together owing to a change in linker orientation, and the coiled-coil stalk becomes stiffer. The net result is a shortening of the molecule coupled to an approximately 15-nm displacement of the tip of the stalk. These changes indicate a mechanism for the dynein power stroke
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