Navigating through digital folders uses the same brain structures as real world navigation

Efficient storage and retrieval of digital data is the focus of much commercial and academic attention. With personal computers, there are two main ways to retrieve files: hierarchical navigation and query-based search. In navigation, users move down their virtual folder hierarchy until they reach the folder in which the target item is stored. When searching, users first generate a query specifying some property of the target file (e.g., a word it contains), and then select the relevant file when the search engine returns a set of results. Despite advances in search technology, users prefer retrieving files using virtual folder navigation, rather than the more flexible query-based search. Using fMRI we provide an explanation for this phenomenon by demonstrating that folder navigation results in activation of the posterior limbic (including the retrosplenial cortex) and parahippocampal regions similar to that previously observed during real-world navigation in both animals and humans. In contrast, search activates the left inferior frontal gyrus, commonly observed in linguistic processing. We suggest that the preference for navigation may be due to the triggering of automatic object finding routines and lower dependence on linguistic processing. We conclude with suggestions for future computer systems design

Leadership and decision-making practices in public versus private universities in Pakistan

The goal of this study is to examine differences in leadership and decision-making practices in public and private universities in Pakistan, with a focus on transformational leadership (TL) and participative decision-making (PDM). We conducted semi-structured interviews with 46 deans and heads of department from two public and two private universities in Pakistan. Our findings indicate that leadership and decision-making practices are different in public and private universities. While differences were observed in all six types of TL-behaviour, the following three approaches emerged to be crucial in both public and private universities: (1) articulating a vision, (2) fostering the acceptance of group goals, and (3) high-performance expectations. In terms of PDM, deans and heads of department in public and private universities adopt a collaborative approach. However, on a practical level this approach is limited to teacher- and student-related matters. Overall, our findings suggest that the leadership and decision-making practices in Pakistani public and private universities are transformational and participative in nature

Fault reactivation in the central Indian Ocean and the rheology of oceanic lithosphere

The intraplate deformation in the central Indian Ocean basin is a well-known example of a deviation from an axiom of plate tectonics: that of rigid plates with deformation concentrated at plate boundaries. Here we present multichannel seismic reflection profiles which show that high-angle reverse faults in the sediments of the central Indian Ocean extend through the crust and possibly into the uppermost mantle. The dip of these faults, which we believe result from the reactivation of pre-existing faults formed at the spreading centre, is ˜40° in the basement, which is consistent with the distribution and focal mechanisms of earthquakes on faults now forming at spreading centres. This style of deformation, coupled with the observation of large earthquakes in the mantle lithosphere, indicates that brittle failure of the oceanic lithosphere may nucleate in the vicinity of the brittle/ductile transition and propagate through the crust

Copycat dynamics in leaderless animal group navigation

Background: Many animals are known to have improved navigational efficiency when moving together as a social group. One potential mechanism for social group navigation is known as the 'many wrongs principle', where information from many inaccurate compasses is pooled across the group. In order to understand how animal groups may use the many wrongs principle to navigate, it is important to consider how directional information is transferred and shared within the group. Methods: Here we use an individual-based model to explore the information-sharing and copying dynamics of a leaderless animal group navigating towards a target in a virtual environment. We assume that communication and information-sharing is indirect and arises through individuals partially copying the movement direction of their neighbours and weighting this information relative to their individual navigational knowledge. Results: We find that the best group navigation performance occurs when individuals directly copy the direction of movement of a subset of their neighbours while only giving a small (6%) weighting to their individual navigational knowledge. Surprisingly, such a strategy is shown to be highly efficient regardless of the level of individual navigational error. We find there is little relative improvement in navigational efficiency when individuals copy from more than 7 influential neighbours. Conclusions: Our findings suggest that we would expect navigating group-living animals to predominantly copy the movement of others rather than relying on their own navigational knowledge. We discuss our results in the context of individual and group navigation behaviour in animals

First-time patellar dislocation with resultant habitual dislocation two years later, which was not demonstrated on plain X-rays halfway: a case report

We present an instructive case of habitual left patellar dislocation in which the patella had appeared odd due to lateral tilt relative to contralateral side, but had been radiologically confirmed to be on the trochlea at 1 year prior to the referral. An 11-year-old girl presented to our hospital 2 years after the left patella had dislocated with a 'giving way' when cutting to the left. Our physical and radiological examinations confirmed that the left patella was laterally tilted in the patellar groove with the knee in extension but was dislocated in flexion beyond 45°. In spite of these findings, she had been untreated at the previous hospital since all plain X-rays, including a skyline patellar view, had failed to demonstrate the dislocation. Consequently, in addition to reconstruction of medial patellofemoral ligament, she had to undergo a lateral retinacular release, which might have been unnecessary if treated earlier. This case illustrates that first-time patellar dislocation can gradually lead to habitual dislocation subsequently, and that cautious physical examinations in regard to patella tracking are essential since radiological examinations do not always reveal the pathophysiology of patellar instability

Abnormalities in autonomic function in obese boys at-risk for insulin resistance and obstructive sleep apnea.

Study objectivesCurrent evidence in adults suggests that, independent of obesity, obstructive sleep apnea (OSA) can lead to autonomic dysfunction and impaired glucose metabolism, but these relationships are less clear in children. The purpose of this study was to investigate the associations among OSA, glucose metabolism, and daytime autonomic function in obese pediatric subjects.MethodsTwenty-three obese boys participated in: overnight polysomnography; a frequently sampled intravenous glucose tolerance test; and recordings of spontaneous cardiorespiratory data in both the supine (baseline) and standing (sympathetic stimulus) postures.ResultsBaseline systolic blood pressure and reactivity of low-frequency heart rate variability to postural stress correlated with insulin resistance, increased fasting glucose, and reduced beta-cell function, but not OSA severity. Baroreflex sensitivity reactivity was reduced with sleep fragmentation, but only for subjects with low insulin sensitivity and/or low first-phase insulin response to glucose.ConclusionsThese findings suggest that vascular sympathetic activity impairment is more strongly affected by metabolic dysfunction than by OSA severity, while blunted vagal autonomic function associated with sleep fragmentation in OSA is enhanced when metabolic dysfunction is also present

Association of MC1R Variants and host phenotypes with melanoma risk in CDKN2A mutation carriers: a GenoMEL study

<p><b>Background</b> Carrying the cyclin-dependent kinase inhibitor 2A (CDKN2A) germline mutations is associated with a high risk for melanoma. Penetrance of CDKN2A mutations is modified by pigmentation characteristics, nevus phenotypes, and some variants of the melanocortin-1 receptor gene (MC1R), which is known to have a role in the pigmentation process. However, investigation of the associations of both MC1R variants and host phenotypes with melanoma risk has been limited.</p> <p><b>Methods</b> We included 815 CDKN2A mutation carriers (473 affected, and 342 unaffected, with melanoma) from 186 families from 15 centers in Europe, North America, and Australia who participated in the Melanoma Genetics Consortium. In this family-based study, we assessed the associations of the four most frequent MC1R variants (V60L, V92M, R151C, and R160W) and the number of variants (1, ≥2 variants), alone or jointly with the host phenotypes (hair color, propensity to sunburn, and number of nevi), with melanoma risk in CDKN2A mutation carriers. These associations were estimated and tested using generalized estimating equations. All statistical tests were two-sided.</p> <p><b>Results</b> Carrying any one of the four most frequent MC1R variants (V60L, V92M, R151C, R160W) in CDKN2A mutation carriers was associated with a statistically significantly increased risk for melanoma across all continents (1.24 × 10−6 ≤ P ≤ .0007). A consistent pattern of increase in melanoma risk was also associated with increase in number of MC1R variants. The risk of melanoma associated with at least two MC1R variants was 2.6-fold higher than the risk associated with only one variant (odds ratio = 5.83 [95% confidence interval = 3.60 to 9.46] vs 2.25 [95% confidence interval = 1.44 to 3.52]; Ptrend = 1.86 × 10−8). The joint analysis of MC1R variants and host phenotypes showed statistically significant associations of melanoma risk, together with MC1R variants (.0001 ≤ P ≤ .04), hair color (.006 ≤ P ≤ .06), and number of nevi (6.9 × 10−6 ≤ P ≤ .02).</p> <p><b>Conclusion</b> Results show that MC1R variants, hair color, and number of nevi were jointly associated with melanoma risk in CDKN2A mutation carriers. This joint association may have important consequences for risk assessments in familial settings.</p&gt

The therapeutic effect of the neuropeptide hormone somatostatin on Schistosoma mansoni caused liver fibrosis

BACKGROUND: The neuropeptide somatostatin is one of the major regulatory peptides in the central nervous system and the digestive tract. Our recent work has delineated an association between fibrosis and low levels of endogenous somatostatin plasma levels in Schistosoma mansoni infected subjects. Based on these results this paper explores the therapeutic potential of somatostatin in a mouse model of hepatic fibrosis associated with S. mansoni infections. METHODS: Groups of outbred Swiss mice were infected with 100 S. mansoni cercariae, infection maintained till weeks 10 or 14, and then somatostatin therapy delivered in two regimens – Either a one or a two-day treatment. All animals were sacrificed one week after therapy and controlled for liver, spleen and total body weight. Circulating somatostatin levels in mice plasma were measured at the time of sacrifice by means of a radio-immuno assay. GraphPad Prism(® )was used for statistical calculations. RESULTS: Somatostatin administration showed little toxicity, probably due to its short half-life. Total liver and spleen weights of S. mansoni infected animals increased over time, with no changes observed due to somatostatin therapy. Total body weights were decreased after infection but were not affected by somatostatin therapy. Snap frozen liver sections were stained with haematoxylin-eosin or Masson's trichrome to study parasite count, hepatocyte status, granuloma size and cellularity. After somatostatin treatment mean egg counts per liver section (43.76 ± 3.56) were significantly reduced as compared to the egg counts in untreated mice after 10 weeks of infection (56.01 ± 3.34) (P = 0.03). Similar significant reduction in parasite egg counts were also observed after somatostatin treatment at 14 weeks of infection (56.62 ± 3.02) as compared to untreated animals (69.82 ± 2.77)(P = 0.006). Fibrosis was assessed from the spectrophotometric determination of tissue hydroxyproline. Infection with S. mansoni caused increased hydroxyproline levels (9.37 ± 0.63 μmol at wk10; 9.65 ± 0.96 μmol at wk14) as compared to uninfected animals (1.06 ± 0.10 μmol). This significant increase in collagen content (P = 0.01; 0.007 respectively) marks the fibrosis observed at these time points. Treatment with somatostatin resulted in a significant decrease in hydroxyproline levels both at wk10 (4.76 ± 0.58 μmol) and at wk14 (5.8 ± 1.13 μmol) (P = 0.01; 0.03 respectively). Endogenous somatostatin levels were increased at wk10 (297 ± 37.24 pg/ml) and wk14 (206 ± 13.30 pg/ml) of infection as compared to uninfected mice (119 ± 11.99 pg/ml) (P = 0.01; 0.008 respectively). Circulating somatostatin levels in infected animals were not significantly affected by somatostatin treatment. Hepatocyte status remained unaltered and granulomas were not remarkably changed in size or cellularity. CONCLUSION: Our experiments reveal an antifibrotic effect of somatostatin in schistosomiasis. We have previously shown that the somatostatin receptors SSTR2 and SSTR3 are present on the parasite egg and worms. We therefore hypothesize that somatostatin reduces either the number of parasite eggs or the secretion of fibrosis inducing-mediators. Our data suggest somatostatin may have therapeutic potential in S. mansoni mediated liver pathology