8,555 research outputs found
Trade, merchant capital, industrial capital, and blocked capitalist development in early state economies
Trade, for many archaeologists, is the means a society employs to maintain or extend its relations and linkages with the outside world. They also see trade as a motor of social and political-economic development leading to and culminating in the rise of civilization and the formation of states. However, by focusing on the distribution of raw materials and artifacts, they typically assume the nature of trade rather than specifying the social relations that underlie the circulation of goods. Furthermore, they rarely treat the analytical category itself as problematicTrade, for many archaeologists, is the means a society employs to maintain or extend its relations and linkages with the outside world. They also see trade as a motor of social and political-economic leading to and culminating in the rise of civilization and the formation of states. However, by focusing on the distribution of raw materials and artifacts, they typically assume the nature of trade rather than specifying the social relations that underlie the circulation of goods. Furthermore, they rarely treat the analytical category itself as problematicTrade, for many archaeologists, is the a society employs to maintain or its relations and linkages with outside world. They also see trade as motor of social and political-economic leading to and culminating the rise of civilization and the states. , by focusing on distribution of raw materials and, typically the nature of trade rather than the social that underlie the circulation of ., they rarely treat category itself as problematic
Bugs and Brains: The Microbiome & Dementia
Interest in the microbiome and its correlation with different neurological diseases has grown significantly over the past decade. The gut microbiome contains a vast array of diverse organisms living in the gastrointestinal (GI) tract. Predominantly composed of bacteria, the gut microbiome helps regulate homeostasis and metabolism in the host, aiding in immune system development as well as vitamin and nutrient absorption. Studies suggest that, in addition to providing humans with these physiological benefits, the gut microbiome is also linked to and communicates with the brain via the gut-brain axis (GBA). Long-standing research on the GBA has demonstrated that the GI tract and the central nervous system are interconnected through both neurological and immunological signaling pathways. Recent research is expanding our understanding of the microbiome and the GBA, revealing correlations between the microbiome impact on the GBA and neurological conditions such as Alzheimer’s dementia and Lewy body dementia, going as far as to identify and highlight specific microbial species that may serve as risk or protective factors for various forms of dementia. This letter aims to highlight the current findings and recommend the use of tools such as microbial cell-free DNA testing to gain a better understanding of the role of gut dysbiosis in dementia patients
Limited Activity Of Miltefosine In Murine Models Of Cryptococcal Meningoencephalitis And Disseminated Cryptococcosis
Miltefosine is an alkyl phosphocholine with good oral bioavailability and in vitro activity against Cryptococcus species that has gained interest as an additional agent for cryptococcal infections. Our objective was to further evaluate the in vivo efficacy of miltefosine in experimental in vivo models of cryptococcal meningoencephalitis and disseminated cryptococcosis. Mice were infected intracranially or intravenously with either C. neoformans USC1597 or H99. Miltefosine treatment (1.8 to 45 mg/kg of body weight orally once daily) began at either 1 h or 1 day postinoculation. Fluconazole (10 mg/kg orally twice daily) or amphotericin B deoxycholate (3 mg/kg intraperitoneally once daily) served as positive controls. In our standard models, miltefosine did not result in significant improvements in survival or reductions in fungal burden against either C. neoformans isolate. There was a trend toward improved survival with miltefosine at 7.2 mg/kg against disseminated cryptococcosis with the H99 strain but only at a low infecting inoculum. In contrast, both fluconazole and amphotericin B significantly improved survival in mice with cryptococcal meningoencephalitis and disseminated cryptococcosis due to USC1597. Amphotericin B also improved survival against both cryptococcal infections caused by H99. Combination therapy with miltefosine demonstrated neither synergy nor antagonism in both models. These results demonstrate limited efficacy of miltefosine and suggest caution with the potential use of this agent for the treatment of C. neoformans infections.Pharmac
Inventando la civilización occidental
The idea of "civilization" evokes powerful images. We learned from elementary school onwards that a few ancient peoples, like the Egyptians or Greeks, were civilized and that civilization has finally achieved its highest level of development in the United States and other Western countries. Civilization is beneficial, desirable, and definitely preferable to being uncivilized. After all, it brings technological progress, greater productivity, and higher standards of living to a few. Moreover, civilized people are and refined, wealthier, and happier than their uncivilized predecessors or neighbors. The idea of civilization has always had its boosters and critics. Here, I want to explore the similarities and in the two perspectivesLa idea de “civilización” evoca ponderosas imágenes. Hemos aprendido desde la primaria y en adelante que unas pocas personas de la antigüedad, como los o los griegos, fueron civilizados y que la civilización ha finalmente su más alto nivel de desarrollo en los Estados Unidos y otros países occidentales. La civilización se presenta como benéfica, deseable, y preferible a ser incivilizado. Después de, ella otorga el progreso tecnológico, la más alta productividad, y los más altos estándares de vida a unos pocos. Por otra parte, la gente es pulida y refinada, más rica y feliz que sus predecesores y vecinos incivilizados. La idea de siempre ha tenido sus impulsores y críticos. Acá, quiero explorar las similitudes y diferencias en las dos.
Evaluation of two selection tests for recruitment into radiology specialty training
BACKGROUND: This study evaluated whether two selection tests previously validated for primary care General Practice (GP) trainee selection could provide a valid shortlisting selection method for entry into specialty training for the secondary care specialty of radiology. METHODS: We conducted a retrospective analysis of data from radiology applicants who also applied to UK GP specialty training or Core Medical Training. The psychometric properties of the two selection tests, a clinical problem solving (CPS) test and situational judgement test (SJT), were analysed to evaluate their reliability. Predictive validity of the tests was analysed by comparing them with the current radiology selection assessments, and the licensure examination results taken after the first stage of training (Fellowship of the Royal College of Radiologists (FRCR) Part 1). RESULTS: The internal reliability of the two selection tests in the radiology applicant sample was good (α ≥ 0.80). The average correlation with radiology shortlisting selection scores was r = 0.26 for the CPS (with p < 0.05 in 5 of 11 shortlisting centres), r = 0.15 for the SJT (with p < 0.05 in 2 of 11 shortlisting centres) and r = 0.25 (with p < 0.05 in 5 of 11 shortlisting centres) for the two tests combined. The CPS test scores significantly correlated with performance in both components of the FRCR Part 1 examinations (r = 0.5 anatomy; r = 0.4 physics; p < 0.05 for both). The SJT did not correlate with either component of the examination. CONCLUSIONS: The current CPS test may be an appropriate selection method for shortlisting in radiology but would benefit from further refinement for use in radiology to ensure that the test specification is relevant. The evidence on whether the SJT may be appropriate for shortlisting in radiology is limited. However, these results may be expected to some extent since the SJT is designed to measure non-academic attributes. Further validation work (e.g. with non-academic outcome variables) is required to evaluate whether an SJT will add value in recruitment for radiology specialty training and will further inform construct validity of SJTs as a selection methodology
Domed, 40-cm-Diameter Ion Optics for an Ion Thruster
Improved accelerator and screen grids for an ion accelerator have been designed and tested in a continuing effort to increase the sustainable power and thrust at the high end of the accelerator throttling range. The accelerator and screen grids are undergoing development for intended use as NASA s Evolutionary Xenon Thruster (NEXT) a spacecraft thruster that would have an input-power throttling range of 1.2 to 6.9 kW. The improved accelerator and screen grids could also be incorporated into ion accelerators used in such industrial processes as ion implantation and ion milling. NEXT is a successor to the NASA Solar Electric Propulsion Technology Application Readiness (NSTAR) thruster - a state-of-the-art ion thruster characterized by, among other things, a beam-extraction diameter of 28 cm, a span-to-gap ratio (defined as this diameter divided by the distance between the grids) of about 430, and a rated peak input power of 2.3 kW. To enable the NEXT thruster to operate at the required higher peak power, the beam-extraction diameter was increased to 40 cm almost doubling the beam-extraction area over that of NSTAR (see figure). The span-to-gap ratio was increased to 600 to enable throttling to the low end of the required input-power range. The geometry of the apertures in the grids was selected on the basis of experience in the use of grids of similar geometry in the NSTAR thruster. Characteristics of the aperture geometry include a high open-area fraction in the screen grid to reduce discharge losses and a low open-area fraction in the accelerator grid to reduce losses of electrically neutral gas atoms or molecules. The NEXT accelerator grid was made thicker than that of the NSTAR to make more material available for erosion, thereby increasing the service life and, hence, the total impulse. The NEXT grids are made of molybdenum, which was chosen because its combination of high strength and low thermal expansion helps to minimize thermally and inertially induced deflections of the grids. A secondary reason for choosing molybdenum is the availability of a large database for this material. To keep development costs low, the NEXT grids have been fabricated by the same techniques used to fabricate the NSTAR grids. In tests, the NEXT ion optics have been found to outperform the NSTAR ion optics, as expected
SPH Simulations of Negative (Nodal) Superhumps: A Parametric Study
Negative superhumps in cataclysmic variable systems result when the accretion
disc is tilted with respect to the orbital plane. The line of nodes of the
tilted disc precesses slowly in the retrograde direction, resulting in a
photometric signal with a period slightly less than the orbital period. We use
the method of smoothed particle hydrodynamics to simulate a series of models of
differing mass ratio and effective viscosity to determine the retrograde
precession period and superhump period deficit as a function of
system mass ratio . We tabulate our results and present fits to both
and versus , as well as compare the
numerical results with those compiled from the literature of negative superhump
observations. One surprising is that while we find negative superhumps most
clearly in simulations with an accretion stream present, we also find evidence
for negative superhumps in simulations in which we shut off the mass transfer
stream completely, indicating that the origin of the photometric signal is more
complicated than previously believed.Comment: 14 pages, 15 figures. Accepted for publication in MNRA
The views and practice of oncologists towards nutritional support in patients receiving chemotherapy
Malnutrition in patients with cancer is common and an adverse prognostic indicator. A questionnaire answered by 357 (72%) UK specialist oncological trainees suggests that they lack the ability to identify factors that place patients at risk from malnutrition. Major barriers to effective nutritional practice included lack of guidelines, knowledge and time
- …