947 resultados para Conditioning place preference


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Référence bibliographique : Rol, 57019

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I am tremendously honored to receive the 2012 Women in Cell Biology Junior Award. In this essay, I recount my career path over the past 15 years. Although many details are specific to my own experiences, I hope that some generalizations can be made to encourage more women to pursue independent scientific careers. Mine is a story of choosing a captivating question, making the most of your opportunities, and finding a balance with life outside the lab.

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These experiments were designed to analyze how medial septal lesions reducing the cholinergic innervation in the hippocampus might affect place learning. Rats with quisqualic lesions of the medial septal area (MS) were trained in a water maze and on a homing table where the escape position was located at a spatially fixed position and further indicated by a salient cue suspended above it. The lesioned rats were significantly impaired in reaching the cued escape platform during training. In addition rats, did not show any discrimination of the training sector during a probe trial in which no platform or cue was present. This impairment remained significant during further training in the absence of the cue. When the cued escape platform was located at an unpredictable spatial location, the MS-lesioned rats showed no deficit and spent more time under the cue than control rats during the probe trial. On the homing board, with a salient object in close proximity to the escape hole, the MS rats showed no deficit in escape latencies, although a significant reduction in spatial memory was observed. However, this was overcome by additional training in the absence of the cue. Under these conditions, rats with septal lesions were prone to develop a pure guidance strategy, whereas normal rats combined a guidance strategy with a memory of the escape position relative to more distant landmarks. The presence of a salient cue appeared to decrease attention to environmental landmarks, thus reducing spatial memory. These data confirm the general hypothesis that MS lesions reduce the capacity to rely on a representation of the relation between several landmarks with different salience.

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The discovery in 1988 of endothelin, the most potent human endogenous vasoconstrictor, has opened the race to the discovery of a new weapon against arterial hypertension. The development of the endothelin receptors antagonists (ERAs) and the demonstration of their efficacy in preclinical models initially raised a wave of enthusiasm, which was however tempered due to their unfavorable side effect profile. In this article we will review the phases of the development ERAs, and their current and future place as therapeutic tool against arterial hypertension.

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There are still many vintage portland cement concrete (PCC) pavements, 18 ft wide (5.4 m), dating back to pre-World War II era in use today. Successive overlays have been placed to cover joints and to improve rideability. The average thickness of the existing asphalt cement concrete (ACC) along route E66 in Tama County, Iowa, was 6.13 in. (15.6 cm). The rehabilitation strategy called for widening the base using the top 3 in. (7.6 cm) of the existing ACC by a recycling process involving cold milling and mixing with additional emulsion/rejuvenator. The material was then placed into a widening trench and compacted to match the level of the milled surface. This project was undertaken to develop a rehabilitation methodology to widen these older pavements economically and to have a finished surface capable of carrying traffic with little or no additional work.

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Training future pathologists is an important mission of many hospital anatomic pathology departments. Apprenticeship-a process in which learning and teaching tightly intertwine with daily work, is one of the main educational methods in use in postgraduate medical training. However, patient care, including pathological diagnosis, often comes first, diagnostic priorities prevailing over educational ones. Recognition of the unique educational opportunities is a prerequisite for enhancing the postgraduate learning experience. The aim of this paper is to draw attention of senior pathologists with a role as supervisor in postgraduate training on the potential educational value of a multihead microscope, a common setting in pathology departments. After reporting on an informal observation of senior and junior pathologists' meetings around the multihead microscope in our department, we review the literature on current theories of learning to provide support to the high potential educational value of these meetings for postgraduate training in pathology. We also draw from the literature on learner-centered teaching some recommendations to better support learning in this particular context. Finally, we propose clues for further studies and effective instruction during meetings around a multihead microscope.

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Velocity-density tests conducted in the laboratory involved small 4-inch diameter by 4.58-inch-long compacted soil cylinders made up of 3 differing soil types and for varying degrees of density and moisture content, the latter being varied well beyond optimum moisture values. Seventeen specimens were tested, 9 with velocity determinations made along two elements of the cylinder, 180 degrees apart, and 8 along three elements, 120 degrees apart. Seismic energy was developed by blows of a small tack hammer on a 5/8-inch diameter steel ball placed at the center of the top of the cylinder, with the detector placed successively at four points spaced 1/2-inch apart on the side of the specimen involving wave travel paths varying from 3.36 inches to 4.66 inches in length. Time intervals were measured using a model 217 micro-seismic timer in both laboratory and field measurements. Forty blows of the hammer were required for each velocity determination, which amounted to 80 blows on 9 laboratory specimens and 120 blows on the remaining 8 cylinders. Thirty-five field tests were made over the three selected soil types, all fine-grained, using a 2-foot seismic line with hammer-impact points at 6-inch intervals. The small tack hammer and 5/8-inch steel ball was, again, used to develop seismic wave energy. Generally, the densities obtained from the velocity measurements were lower than those measured in the conventional field testing. Conclusions were reached that: (1) the method does not appear to be usable for measurement of density of essentially fine-grained soils when the moisture content greatly exceeds the optimum for compaction, and (2) due to a gradual reduction in velocity upon aging, apparently because of gradual absorption of pore water into the expandable interlayer region of the clay, the seismic test should be conducted immediately after soil compaction to obtain a meaningful velocity value.

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Usefulness of a predictive score in subarachnoid hemorrhage diagnosis Nearly half of the patients with non-traumatic subarachnoid hemorrhage (SAH) present with no neurological signs, inducing clinical underestimation of the gravity of their affection. As the outcome of aneurismal SAH is highly dependant on the initial neurological status and the recurrence of untreated hemorrhagic events, these neurologically intact patients stand to suffer the most from delayed diagnosis. Although there is currently no validated predictive score that reliably identifies SAH-induced headache, a combination of clinical criteria derived from a cohort of sudden-onset headache patients should allow risk stratification and identification of those patients requiring further investigation.

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There is a sustained controversy in the literature about the role and utility of self-monitoring of blood glucose (SMBG) in type 2 diabetes. The study results in this field do not provide really useful clues for the integration of SMBG in the follow-up of the individual patient, because they are based on a misconception of SMBG. It is studied as if it was a medical treatment whose effect on glycemic control is to be isolated. However, SMBG has no such intrinsic effect. It gains its purpose only as an inseparable component of a comprehensive and structured educational strategy. To be appropriate this strategy cannot be based on the health care professionals' view on diabetes only. It rather has to be tailored to the individual patient's needs through an ongoing process of shared reflection with him.