5,121 research outputs found

    Special Relativity

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    The results of an agricultural analysis of the ERTS-1 MSS data at the Johnson Space Center

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    The initial analysis of the ERTS-1 multispectral scanner (MSS) data at the Johnson Space Center (JSC), Houston, Texas is discussed. The primary data set utilized was the scene over Monterey Bay, California, on July 25, 1972, NASA ERTS ID No. 1002-18134. It was submitted to both computerized and image interpretative processing. An area in the San Joaquin Valley was submitted to an intensive evaluation of the ability of the data to (1) discriminate between crop types and (2) to provide a reasonably accurate area measurement of agricultural features of interest. The results indicate that the ERTS-1 MSS data is capable of providing the identifications and area extent of agricultural lands and field crop types

    Prenatal diagnosis and follow-up of congenital splenic cysts

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    Los quistes esplénicos congénitos son entidades poco frecuentes, particularmente en la edad pediátrica. En la literatura especializada existen pocos casos publicados con diagnóstico durante el período prenatal. Los autores describen 2 casos clínicos, identificados por ecografía prenatal a las 34 y 30 semanas de gestación, y su evolución posnatal hasta su resolución espontánea a los 5 meses y a los 2 años de vida, respectivamente. Se revisa la etiología, clínica y evolución de esta patología.Congenital splenic cysts are uncommon entities, especially in children. Few cases diagnosed in the prenatal period have been reported in the literature. We describe two cases that were identified by prenatal sonography at 34 and 30 gestational weeks. Their follow- up until spontaneous full regression at 5 months and 2 years, respectively, is discussed. The etiology, clinical findings, and clinical course of this entity are reviewed

    Poisoning with the recreational drug paramethoxyamphetamine ("death")

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    The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Objective: To describe the clinical features of paramethoxyamphetamine (PMA; "death") poisoning and to compare these with those of people with self-reported "ecstasy" poisoning. Design: Retrospective casenote review. Participants and setting: 22 patients who presented to the Emergency Department of the Royal Adelaide Hospital (RAH), a major metropolitan teaching hospital, between 1 January 1996 and 31 December 1998 with PMA poisoning identified through urine drug screens; and 61 patients with self-reported ecstasy poisoning between 1 September 1997 and 31 December 1998 found through the hospital databases. Results: Patients with PMA poisoning presented with tachycardia (64%), hyperthermia (temperature > 37.5ºC; 36%), coma (41%), seizures (32%), arrhythmias (23%), and QRS intervals 100 ms (50%) with greater frequency and often greater severity than those with self-reported ecstasy poisoning. Two patients with PMA poisoning presented with severe hypoglycaemia (blood glucose level, 7.5 mmol/L). Conclusions: At our hospital, PMA poisonings accounted for most of the severe reactions among people who believed they had taken ecstasy. Hypoglycaemia and hyperkalaemia may be specific to PMA poisoning. PMA toxicity should be suspected with severe or atypical reactions to "ecstasy", and confirmed by chromatographic urine drug screens.Liang Han Ling, Colin Marchant, Nicholas A. Buckley, Michael Prior and Rod J. Irvin

    New Hamiltonian formalism and quasi-local conservation equations of general relativity

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    I describe the Einstein's gravitation of 3+1 dimensional spacetimes using the (2,2) formalism without assuming isometries. In this formalism, quasi-local energy, linear momentum, and angular momentum are identified from the four Einstein's equations of the divergence-type, and are expressed geometrically in terms of the area of a two-surface and a pair of null vector fields on that surface. The associated quasi-local balance equations are spelled out, and the corresponding fluxes are found to assume the canonical form of energy-momentum flux as in standard field theories. The remaining non-divergence-type Einstein's equations turn out to be the Hamilton's equations of motion, which are derivable from the {\it non-vanishing} Hamiltonian by the variational principle. The Hamilton's equations are the evolution equations along the out-going null geodesic whose {\it affine} parameter serves as the time function. In the asymptotic region of asymptotically flat spacetimes, it is shown that the quasi-local quantities reduce to the Bondi energy, linear momentum, and angular momentum, and the corresponding fluxes become the Bondi fluxes. The quasi-local angular momentum turns out to be zero for any two-surface in the flat Minkowski spacetime. I also present a candidate for quasi-local {\it rotational} energy which agrees with the Carter's constant in the asymptotic region of the Kerr spacetime. Finally, a simple relation between energy-flux and angular momentum-flux of a generic gravitational radiation is discussed, whose existence reflects the fact that energy-flux always accompanies angular momentum-flux unless the flux is an s-wave.Comment: 36 pages, 3 figures, RevTex

    ‘It’s better than daytime television’: questioning the socio-spatial impacts of massage parlours on residential communities

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    It has been shown that street sex work is problematic for some communities, but there is less evidence of the effects of brothels. Emerging research also suggests that impact discourses outlined by residential communities and in regulatory policies should be critiqued, because they are often based on minority community voices, and limited tangible evidence is used to masquerade wider moral viewpoints about the place of sex work. Using a study of residents living in close proximity to brothels in Blackpool, this paper argues that impact is socially and spatially fluid. Impact needs to be evaluated in a more nuanced manner, which is considerate of the heterogeneity of (even one type of) sex work, and the community in question. Brothels in Blackpool had a variety of roles in the everyday socio-spatial fabric; thus also questioning the common assumption that sex work only impacts negatively on residential communities

    Rich Situated Attitudes

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    We outline a novel theory of natural language meaning, Rich Situated Semantics [RSS], on which the content of sentential utterances is semantically rich and informationally situated. In virtue of its situatedness, an utterance’s rich situated content varies with the informational situation of the cognitive agent interpreting the utterance. In virtue of its richness, this content contains information beyond the utterance’s lexically encoded information. The agent-dependence of rich situated content solves a number of problems in semantics and the philosophy of language (cf. [14, 20, 25]). In particular, since RSS varies the granularity of utterance contents with the interpreting agent’s informational situation, it solves the problem of finding suitably fine- or coarse-grained objects for the content of propositional attitudes. In virtue of this variation, a layman will reason with more propositions than an expert
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