12,236 research outputs found

    "Rapid and dramatic changes in vegetation" of a small pond on Holy Island (Northumbria): Chaotic dynamics?

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    This note describes changes to the relative extent of four structurally dominant submerged macrophytes in a pond on Holy Island National Nature Reserve, Northumbria, between 1991 and 1998. The estimated extent of the four submerged macrophytes and bare substratum between 1991 and 1998 showed dramatic changes with no obvious pattern or periodicity, as well as no identifiable natural or anthropogenic causes. Chaotic variation may be an important character of submerged pond plant populations, so that surveys taken in a single year may give an unreliable picture of plant populations

    Management of rapid eye movement sleep behavior disorder in patients with Parkinson's disease

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    Among all of the devastating effects that Parkinson’s disease (PD) has on an individual, sleep dysfunction is one that can have a profound effect on the entire family of the patient. The most potentially destructive of these sleep syndromes being that of Rapid Eye Movement Sleep Behavior Disorder (RBD). This disorder not only causes sleep impairment to the patient, but can occasionally result in life-threatening injury to the individual or their bed partner. While this condition is manageable with medication, the current treatment of choice is a long-acting benzodiazepine, clonazepam. This drug, while effective in treating RBD, comes with a significant burden of side effects. Patients with neurodegenerative disorders, like PD, are at even higher risk of suffering the negative impacts of this treatment. One potential alternative treatment that has been considered is a supplement of exogenous melatonin, a hormone that plays a role in maintaining one’s circadian rhythm. Several small case studies have shown potential efficacy of this treatment, and with very few side effects. However, this efficacy has not yet been proven by randomized clinical trial. This proposed study will perform a double-blind randomized clinical trial of melatonin vs. placebo in a population of PD patients with RBD. Subjects will be analyzed via polysomnographic sleep study, where symptoms will be scored on the RBD Severity Scale (RBDSS) at baseline and after a treatment intervention. Statistical analysis will then ascertain whether or not a significant symptom reduction is seen following melatonin treatment, compared to a group receiving placebo. If melatonin proves to be efficacious in this patient population, this would give clinicians a new treatment option to consider to effectively manage symptoms of RBD with a much lower risk of potentially harmful side effects. Finding an effective method of managing this condition, the prevalence of which continues to rise worldwide, will have a great impact on improving the safety and quality of life of these patients

    Gendered judgments: Differentiation in criminal court outcomes

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    A summary of international and national research shows that, in comparison to men, women generally receive less severe judicial outcomes (e.g. sentences) even when they appear before the court under seemingly similar circumstances. Such a finding leads to the questions: How do we interpret these differences between men and women? Is this disparity in criminal court outcomes just or unjust, warrant or unwarranted? In this paper, I will explore these questions by addressing feminist debates of equality versus difference in the context of criminal court sanctioning

    The Dirichlet problem

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    Thesis (M.A.)--Boston UniversityThe problem of finding the solution to a general eliptic type partial differential equation, when the boundary values are given, is generally referred to as the Dirichlet Problem. In this paper I consider the special eliptic equation of ∇2 J=0 which is Laplace's equation, and I limit myself to the case of two dimensions. Subject to these limitations I discuss five proofs for the existence of a solution to Laplace's equation for arbitrary regions where the boundary values are given. [TRUNCATED

    On the lithium abundance dispersion in late-type Pleiades stars

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    I present the results of a programme to monitor the strengths of the Li I 6708A, K I 7699A and chromospheric Halpha lines in a group of cool Pleiades stars. Consistent instrumentation and analysis techniques are used to show that there is no Li I variability on timescales of 1 year that could possibly account for the apparent spread in Li abundances seen in Pleiades stars between effective temperatures of 4800-5200K. Comparison with published data reveals tentative evidence for variability on 10 year timescales, but at a very low level. The lack of chromospheric activity variability above levels of 20 to 30 percent makes it difficult however, to rule out evenly distributed magnetic activity regions causing a scatter in the Li I line strengths at a given abundance. The similar star to star scatter of K I line strengths in these and published data reinforces the conclusion that it is still unsafe to attribute the Li I line strength dispersion to a large variation in Li depletion at a given mass.Comment: Latex 7 pages, 3 postscript figures to appear in MNRA

    Skills for Creativity in Games Design (Part 2) Practitioner Conceptions of Creativity in Games Design.

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    Skills for creativity in games design

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    This paper reports on an experimental study to understand further the extent to which academics may differ to practitioners in their conception of skills relevant to creativity within a specific design related subject: in this instance, Games Design. Ten academics, sampled from BA Hons games courses in the UK, participated in identifying what factors they each considered important to creativity in games design, and how, collectively, they rated particular skills, knowledge, talents and abilities relevant to creativity in games design. With the same research methodology, theoretical framework and procedures, the focus was placed on ten games design practitioners’ conceptions of skills for creativity in games design. A detailed comparison is made between the findings from both groups

    Using rotation, magnetic activity and lithium to estimate the ages of low mass stars

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    The rotation rate, level of magnetic activity and surface lithium abundance are age-dependent quantities in stars of about a solar mass and below. The physical reasons for the evolution of these phenomena are qualitatively understood, but accurate quantitative models remain dependent on empirical calibration using the Sun and stars of known age, chiefly in clusters. In this work I review the status of these "empirical age indicators", outlining the astrophysics of their time dependence, describing the measurements, assessing the precision (and accuracy) of age estimates when applied to individual stars, and identifying their principle limitations in terms of the mass and age ranges over which they are useful. Finally, I discuss the "lithium depletion boundary" technique which, in contrast to the empirical methods, appears to provide robust, almost model-independent ages that are both precise and accurate, but which is only applicable to coeval groups of stars.Comment: 38 pages; contribution to the proceedings of the 23rd Evry Schatzman School on Stellar Astrophysics, "The Ages of Stars", Roscoff 2013, EAS Publications Series, eds. C. Charbonnel et al. This version has minor corrections/additions to the bibliograph
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