281 research outputs found

    Do wholes become more than the sum of their parts in the rodent (Rattus Norvegicus) visual system? A test case with the configural superiority effect

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    The rodent has been used to model various aspects of the human visual system, but it is unclear to what extent human visual perception can be modelled in the rodent. Research suggests rodents can perform invariant object recognition tasks in a manner comparable to humans. There is further evidence that rodents also make use of certain grouping cues, but when performing a shape discrimination they have a tendency to rely much more on local image cues than human participants. In the current work, we exploit the fact that humans sometimes discriminate better between whole shapes, rather than the parts from which they are constructed, to ask whether rodents show a classic Configural Superiority Effect. Using touchscreen-equipped operant boxes, rats were trained to discriminate ‘part’ or ‘whole’ images based off of those used by J. R. Pomerantz et al. (1977) J Exp Psychol Hum Percept Perform, 3, 422–435. Here, we show that rats show no advantage for wholes and that they perform better when presented with simpler image parts, a pattern of effect opposite to what was seen in humans when highly comparable stimuli were used. These results add to our understanding of the similarities and differences between the human and rodent visual system, and suggest that the rodent visual system may not compute part whole relationships in a way comparable to humans. These results are significant from both a comparative anatomy perspective, and of particular relevance for those wishing to use rodents to model visuo-perceptual deficits associated with human psychiatric disorders

    Collicular circuits for flexible sensorimotor routing

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    Context-based sensorimotor routing is a hallmark of executive control. Pharmacological inactivations in rats have implicated the midbrain superior colliculus (SC) in this process. But what specific role is this, and what circuit mechanisms support it? Here we report a subset of rat SC neurons that instantiate a specific link between the representations of context and motor choice. Moreover, these neurons encode animals’ choice far earlier than other neurons in the SC or in the frontal cortex, suggesting that their neural dynamics lead choice computation. Optogenetic inactivations revealed that SC activity during context encoding is necessary for choice behavior, even while that choice behavior is robust to inactivations during choice formation. Searches for SC circuit models matching our experimental results identified key circuit predictions while revealing some a priori expected features as unnecessary. Our results reveal circuit mechanisms within the SC that implement response inhibition and context-based vector inversion during executive control

    Coeducation:A Contested Practice in Nineteenth- and Twentieth-Century Secondary Schooling

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    This chapter discusses the history of coeducation in secondary schooling, mainly in Europe and North America. The analysis focuses on the gendered characteristics of educational systems and curricula, as well as on national discourses about single-sex or mixed schooling. The focus is on the latter half of the nineteenth and the first decades of the twentieth century, when the merits and perils of coeducation were debated for this stage of schooling. Until after World War II, children of the working class hardly ever attended school past the age of 13 or 14. Therefore, this is a history of middle- and upper-class education. In the early nineteenth century, girls had to do with a very limited, private education that prepared only for homemaking and motherhood, while boys could attend public grammar schools that opened the door to the university and the professions. From the mid-nineteenth century, initiatives to improve the quality of girls’ education were taken. Few countries opened up boys’ public schools for girls; in most cases, new girls’ schools were established with more serious but still unequal curricula, focusing mainly on humanities. Schools teaching a curriculum equivalent to that of the boys’ schools were not created until after the turn of the century, when a more critical view of coeducation became the rule. Democratization and coeducation came hand in hand with the introduction of comprehensive mixed secondary schooling in the 1960s and 1970s. The shortcomings of coeducation, however, were not rediscovered until after it had generally been introduced

    Anti-angiogenic effect of high doses of ascorbic acid

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    Pharmaceutical doses of ascorbic acid (AA, vitamin C, or its salts) have been reported to exert anticancer activity in vitro and in vivo. One proposed mechanism involves direct cytotoxicity mediated by accumulation of ascorbic acid radicals and hydrogen peroxide in the extracellular environment of tumor cells. However, therapeutic effects have been reported at concentrations insufficient to induce direct tumor cell death. We hypothesized that AA may exert anti-angiogenic effects. To test this, we expanded endothelial progenitor cells (EPCs) from peripheral blood and assessed, whether or not high dose AA would inhibit EPC ability to migrate, change energy metabolism, and tube formation ability. We also evaluated the effects of high dose AA on angiogenic activities of HUVECs (human umbilical vein endothelial cells) and HUAECs (human umbilical arterial endothelial cells). According to our data, concentrations of AA higher than 100 mg/dl suppressed capillary-like tube formation on Matrigel for all cells tested and the effect was more pronounced for progenitor cells in comparison with mature cells. Co-culture of differentiated endothelial cells with progenitor cells showed that there was incorporation of EPCs in vessels formed by HUVECs and HUAECs. Cell migration was assessed using an in vitro wound healing model. The results of these experiments showed an inverse correlation between AA concentrations relative to both cell migration and gap filling capacity. Suppression of NO (nitric oxide) generation appeared to be one of the mechanisms by which AA mediated angiostatic effects. This study supports further investigation into non-cytotoxic antitumor activities of AA

    Lemierre's syndrome due to Klebsiella pneumoniae in a 63-year-old man with diabetes: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Lemierre's syndrome was originally documented to be caused by <it>Fusobacterium necrophorum</it>. It is a very rare condition with a prevalence of one to 14.4 instances per million. Its presentation is varied, not only in composition but also in the infecting organism. Treatment with anticoagulants has been controversial and applied only on a case-by-case basis.</p> <p>Case presentation</p> <p>A 63-year-old Saudi man who had had uncontrolled diabetes mellitus for 47 years presented to our facility with a five-day history of swelling on the right side of his neck and fever. The swelling progressively increased in size and was associated with pain, dysphagia, odynophagia, change of voice ('hot potato voice'), and reduced appetite. Abscess content culture and sensitivity testing revealed <it>Klebsiella pneumoniae</it>. However, blood culture results were repeatedly negative. The abscess was incised and drained without any complication. Our patient was treated with clindamycin and cefuroxime. Warfarin was also administered concurrently for six weeks, for an isolated internal jugular vein thrombosis (IJV), with complete resolution of the thrombus. Normoglycemia was achieved and our patient was discharged after complete wound healing and the return of his biochemical parameters to normal.</p> <p>Conclusions</p> <p>Only two cases of Lemierre's syndrome in patients with diabetes due to <it>K. pneumoniae </it>have been reported previously. A review of the literature suggested that an association exists between deep neck infections due to <it>K. pneumoniae </it>and diabetes mellitus. The reasons for this association are still not clear. This poses a question as to whether diabetes mellitus specifically predisposes these patients to infection with this organism. It is suggested that clinicians should consider infectious agents other than <it>F. necrophorum </it>in the causation of Lemierre's syndrome, especially in patients with diabetes.</p

    Coupling models of cattle and farms with models of badgers for predicting the dynamics of bovine tuberculosis (TB)

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    Bovine TB is a major problem for the agricultural industry in several countries. TB can be contracted and spread by species other than cattle and this can cause a problem for disease control. In the UK and Ireland, badgers are a recognised reservoir of infection and there has been substantial discussion about potential control strategies. We present a coupling of individual based models of bovine TB in badgers and cattle, which aims to capture the key details of the natural history of the disease and of both species at approximately county scale. The model is spatially explicit it follows a very large number of cattle and badgers on a different grid size for each species and includes also winter housing. We show that the model can replicate the reported dynamics of both cattle and badger populations as well as the increasing prevalence of the disease in cattle. Parameter space used as input in simulations was swept out using Latin hypercube sampling and sensitivity analysis to model outputs was conducted using mixed effect models. By exploring a large and computationally intensive parameter space we show that of the available control strategies it is the frequency of TB testing and whether or not winter housing is practised that have the most significant effects on the number of infected cattle, with the effect of winter housing becoming stronger as farm size increases. Whether badgers were culled or not explained about 5%, while the accuracy of the test employed to detect infected cattle explained less than 3% of the variance in the number of infected cattle

    Methylphenidate significantly improves declarative memory functioning of adults with ADHD

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    Contains fulltext : 87790.pdf (publisher's version ) (Closed access)BACKGROUND: Declarative memory deficits are common in untreated adults with attention-deficit hyperactivity disorder (ADHD), but limited evidence exists to support improvement after treatment with methylphenidate. The objective of this study was to examine the effects of methylphenidate on memory functioning of adults with ADHD. METHODS: Eighteen adults with ADHD who were clinical responders to methylphenidate participated in this randomized crossover trial. After 3 days of no treatment, patients received in random order either their usual methylphenidate dose (mean: 14.7 mg; range: 10-30 mg) or placebo, separated by a 6-7-day washout period. Patients performed an immediate word recall test 1 h after treatment administration. Three hours after intake, patients performed the second part of the memory test (delayed word recall and a recognition test). RESULTS: Delayed recognition and immediate recall was similar on treatment and on placebo. Delayed word recall was significantly better in the methylphenidate than in the placebo condition (F (1, 17) = 7.0, p < 0.017). A significant correlation was found between prestudy CES-D depression scores and difference scores on delayed recall (r = 0.602, p < 0.008). CONCLUSION: Methylphenidate improves declarative memory functioning in patients with ADHD. New studies should further examine whether subclinical depressive symptoms mediate the effect of methylphenidate on declarative memory.1 oktober 201

    From universal service to universal connectivity

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    Two features of the century-old policy goal of promoting universal telephone service in the United States have been enduring. Policymakers have focused on (1) wireline telephone (and more recently, fixed-line broadband) services and (2) households. The widespread adoption of mobile telephones compels a fresh examination of this focus. We construct a new measure of universal connectivity which accounts for consumers’ choices of communications technologies and for their geographic mobility over the course of the day. This measure, in turn, compels a conceptual and empirical investigation of the determinants of mobile telephone diffusion within families. Our estimations of intra-household demand for mobile service permit us to develop simulations that estimate the economic impact of modernizing a key element of existing universal service policy (viz., the Lifeline Program) to reflect the goal of improving individual connectivity. We find that a policy expansion from a single subsidy per household to multiple subsidies per eligible household members would increase mobile subscriptions by 2.25 million and Lifeline costs by $250 million

    Renal function in HIV-infected children and adolescents treated with tenofovir disoproxil fumarate and protease inhibitors

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    <p>Abstract</p> <p>Background</p> <p>Kidney disease is an important complication in HIV infected people, and this may be related to infection or antiretroviral therapy (ART). Our aim is to assess renal function in HIV infected paediatric patients, who may be particularly affected and are likely to take ART for longer than adults, and investigate the long term role of Tenofovir Disoproxil Fumarate (TDF) alone or co-administered with Ritonavir-boosted Protease Inhibitors (PI).</p> <p>Methods</p> <p>Serum creatinine, phosphate and potassium levels, with estimated Glomerular Filtration Rate (eGFR), had been prospectively evaluated for 2 years in a cohort of HIV infected children and adolescents (age 9-18) on ART, and data analyzed according to the exposure to TDF or simultaneous TDF and PI.</p> <p>Results</p> <p>Forty-nine patients were studied (57% female, mean age 14). Sixty-three percent were treated with ART containing TDF (Group A), and 37% without TDF (Group B); 47% with concomitant use of TDF and PI (Group C) and 53% without this combination (Group D). The groups didn't differ for age, gender or ethnicity. The median creatinine increased in the entire cohort and in all the groups analyzed; eGFR decreased from 143.6 mL/min/1.73 m<sup>2 </sup>at baseline to 128.9 after 2 years (<it>p </it>= 0.006) in the entire cohort. Three patients presented a mild eGFR reduction, all were on TDF+PI. Phosphatemia decreased significantly in the entire cohort (<it>p </it>= 0.0003) and in TDF+PI group (<it>p </it>= 0.0128) after 2 years. Five patients (10%) developed hypophosphatemia (Division of Acquired Immune Deficiency AE grade 1 or 2), and four of them were on TDF+PI.</p> <p>Conclusions</p> <p>Renal function decrease and hypophosphatemia occur over time in HIV infected children and adolescents on ART. The association with co-administration of TDF and PI appears weak, and further studies are warranted.</p
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