11,929 research outputs found

    The Use of the Scanning Electron Microscope in Studying the Heat Treatment of Prehistoric Lithic Artifacts from the North Florida Weeden Island Period McKeithen Site

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    In this paper, I discuss a study in which I attempted to determine whether or not the inhabitants of the McKeithen site, a Weeden Island Period mound and village complex in what is today northern Florida, employed heat treatment as part of their lithic reduction technology, and if so, at what point in the reduction sequence it was conducted. I used a scanning electron microscope (SEM) to photograph raw and heat treated control samples of northern Florida chert, then debitage and tools of chert and silicified coral from the McKeithen site which represented the range of colors and luster present in the assemblage. A comparison of the photographs of the controls with those of the archaeological specimens showed that the McKeithen knappers did heat treat some of their lithic materials. Based on this sample, I determined that about 16% of the chert and 38% of the silicified coral had been heat treated. In general, the McKeithen knappers brought potential cores to the village from nearby quarries, heat treated some of them, then detached flakes from them and reduced the flakes, and occasionally the cores, into tools. While this study largely corroborates the finding that luster is a better macroscopic indicator of heat treatment than color change, exceptions occurred which demonstrate the necessity of using instrumental techniques to accurately detect heat treatment

    Transcutaneous electrical nerve stimulation for cancer pain in adults.

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    Background Cancer-related pain is complex and multi-dimensional but the mainstay of cancer pain management has predominately used a biomedical approach. There is a need for non-pharmacological and innovative approaches. Transcutaneous Electric Nerve Stimulation (TENS) may have a role for a significant number of patients but the effectiveness of TENS is currently unknown. Objectives The aim of this systematic review was to determine the effectiveness of TENS for cancer-related pain in adults. Search strategy We searched The Cochrane Library, MEDLINE, EMBASE, CINAHL, PsychINFO, AMED and PEDRO databases (11/04/08). Selection criteria Only randomised controlled trials (RCTS) investigating the use of TENS for the management of cancer-related pain in adults were included. Data collection and analysis The search strategy identified 37 possible published studies which were divided between two pairs of review authors that decided on study selection. A study eligibility form was used to screen each abstract and where study eligibility could not be determined from the abstract, the full paper was obtained and assessed by one pair of review authors. A standardised data extraction sheet was used to collect information on the studies and the quality of the studies was assessed independently by two review authors using the validated five-point Oxford Quality Scale. Final scores were discussed and agreed between all four review authors. The small sample sizes and differences in patient study populations of the two included studies prevented meta-analysis. Main results Only two RCTs met the eligibility criteria (64 participants). These studies were heterogenous with respect to study population, sample size, study design, methodological quality, mode of TENS, treatment duration, method of administration and outcome measures used. In one RCT, there were no significant differences between TENS and placebo in women with chronic pain secondary to breast cancer treatment. In the other RCT, there were no significant differences between acupuncture-type TENS and sham in palliative care patients; this study was underpowered. Authors' conclusions The results of this systematic review are inconclusive due to a lack of suitable RCTs. Large multi-centre RCTs are required to assess the value of TENS in the management of cancer-related pain in adults

    Casimir repulsion between metallic objects in vacuum

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    We give an example of a geometry in which two metallic objects in vacuum experience a repulsive Casimir force. The geometry consists of an elongated metal particle centered above a metal plate with a hole. We prove that this geometry has a repulsive regime using a symmetry argument and confirm it with numerical calculations for both perfect and realistic metals. The system does not support stable levitation, as the particle is unstable to displacements away from the symmetry axis.Comment: 4 pages, 4 figures; added references, replaced Fig.

    Expertise in Trial Advocacy: Some Considerations for Inquiry into Its Nature and Development

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    It is the central thesis of this paper that what is needed to assess the validity of many of the criticisms directed toward legal practice and training, and to resolve many of the controversies surrounding attempts to correct these criticisms, is a representation or documentation of the structure of expertise in legal practice - especially in trial advocacy since this represents the focus of most complaints. Without such a representation it is difficult to support allegations of incompetence or to defend the efficiency of specific reform on other than subjective or intuitive grounds. At this time no systematic representation exists

    A review of the characteristics and treatment progress of 45 pregnant opiate addicts attending the Irish National Drug Advisory and Treatment Centre over a two year period.

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    The increase in the number of patients presenting to the National Drug Advisory and Treatment Centre addicted to opiates has been accompanied by an increase in the number of pregnant opiate addicts attending for treatment. Studies published in January 1982 referred to the emergence of maternal addiction as a serious problem in Ireland. Since then the escalation of this specific problem has continued and a programme designed to meet the needs of the pregnant addict was initiated at the clinic. This paper reviews the characteristics and treatment progress of 45 opiate addicts who were referred to the clinic over a two year period

    Carbon and Strontium Abundances of Metal-Poor Stars

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    We present carbon and strontium abundances for 100 metal-poor stars measured from R∼\sim 7000 spectra obtained with the Echellette Spectrograph and Imager at the Keck Observatory. Using spectral synthesis of the G-band region, we have derived carbon abundances for stars ranging from [Fe/H]=−1.3=-1.3 to [Fe/H]=−3.8=-3.8. The formal errors are ∼0.2\sim 0.2 dex in [C/Fe]. The strontium abundance in these stars was measured using spectral synthesis of the resonance line at 4215 {\AA}. Using these two abundance measurments along with the barium abundances from our previous study of these stars, we show it is possible to identify neutron-capture-rich stars with our spectra. We find, as in other studies, a large scatter in [C/Fe] below [Fe/H]=−2 = -2. Of the stars with [Fe/H]<−2<-2, 9±\pm4% can be classified as carbon-rich metal-poor stars. The Sr and Ba abundances show that three of the carbon-rich stars are neutron-capture-rich, while two have normal Ba and Sr. This fraction of carbon enhanced stars is consistent with other studies that include this metallicity range.Comment: ApJ, Accepte

    Estimation of meiosis and sporulation efficiencies in the fission yeast by ascus analysis.

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    SUMMARYPopulations of linear asci are classified according to the number of spores in an ascus. The resultant five numerical classes are further classified into ten spatial classes according to the arrangement of the spores in an ascus and, by inference, into ten historical classes according to the number and origins of failures during the developmental process. An analysis of the observed frequencies of numerical classes allows derivation of the efficiencies of the first meiotic division, the second meiotic division and sporulation in a fission yeast. The analytical method may be useful in locating the site of action of sporulation inhibitors and in identifying meiosis mutants from sporulation mutants
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