44 research outputs found

    Learning activation functions from data using cubic spline interpolation

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    Neural networks require a careful design in order to perform properly on a given task. In particular, selecting a good activation function (possibly in a data-dependent fashion) is a crucial step, which remains an open problem in the research community. Despite a large amount of investigations, most current implementations simply select one fixed function from a small set of candidates, which is not adapted during training, and is shared among all neurons throughout the different layers. However, neither two of these assumptions can be supposed optimal in practice. In this paper, we present a principled way to have data-dependent adaptation of the activation functions, which is performed independently for each neuron. This is achieved by leveraging over past and present advances on cubic spline interpolation, allowing for local adaptation of the functions around their regions of use. The resulting algorithm is relatively cheap to implement, and overfitting is counterbalanced by the inclusion of a novel damping criterion, which penalizes unwanted oscillations from a predefined shape. Experimental results validate the proposal over two well-known benchmarks.Comment: Submitted to the 27th Italian Workshop on Neural Networks (WIRN 2017

    How do gender quotas affect workplace relationships? Complementary evidence from a representative survey and labor market experiments

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    This is the author accepted manuscript. The final version is available from INFORMS via the DOI in this recordGender quotas are frequently proposed to address persistent gender imbalances in managerial roles. However, it is unclear how quotas for female managers affect organizations and whether quotas improve or damage relationships between managers and their subordinates. We conduct a representative survey to study opinions on quotas for female managers and, based upon the survey, design a novel set of experiments to investigate how quotas influence wage setting and effort provision. Our findings reveal that both opinions about gender quotas and workplace behavior crucially depend on the workplace environment. In our survey, we observe that approval for gender quotas is low if women are not disadvantaged in the manager-selection process, regardless of whether there are gender differences in performance. Complementing this evidence, we observe in our experiments that quotas lead to lower effort levels and lower wages in such environments. By contrast, in environments in which women are disadvantaged in the selection process, we observe a higher approval of quotas as well as higher effort levels and higher wages. These findings are consistent with the concept of meritocracy and suggest that it is important to evaluate the perception of gender disadvantages in the workplace environment before implementing quotas.Australian Research Council (ARC)Swedish Research Counci

    Do Financial Incentives Encourage Women to Apply for a Tech Job? Evidence from a Natural Field Experiment

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    This is the final version. Available from the American Economic Association via the DOI in this recordWe conduct a natural field experiment to test whether offering financial incentives encourages more female job seekers to complete their applications for a tech job. All eligible applicants for the job were invited to perform an online skill assessment. We randomized whether or not they were offered an incentive of up to $10 for completing the assessment. We find no significant effect of the incentive for female applicants (or male applicants).Australian Research Council (ARC

    OCHRONOTIC ARTHROPATHY - STRUCTURAL AND ULTRASTRUCTURAL FEATURES

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    Fragments of articular cartilage and synovial membrane in a case of ochronosis were studied by light microscopy (LM), polarized light, and transmission electron microscopy (TEM). Granular and/or shard-shaped pigments were observed in the synovia, cartilage, and subchondral tissue, and dispersed pigment was also seen in the synovial fluid. Zones of the articular cartilage surface showed small erosions near shards, and sometimes, when the degenerative process was in an advanced stage, a substitutive fibrosis of the cartilage edge was demonstrated. LM and TEM observations of the samples studied revealed an alteration of collagen fibrils that appeared wavy and sometimes fragmented with loss of periodicity. They were always mixed with the dispersed pigment. A peculiar finding that characterized this ochronotic case was the complete absence of inflammatory infiltrates or signs of monocyte-macrophage activation. These structural and ultrastructural observations suggest that the pigment deposition in the articular surfaces was due to the synovial fluid circulation and partially to subchondral blood flow, which transports and stores the ochronotic pigments in the synovia and cartilage. These etiopathologic elements associated with the mechanical pathogenesis naturally present in the joints can contribute to the explanation of the pathogenesis and origin of ochronotic arthropath

    Eastward Surface Jets in the Central Equatorial Pacific, November 1991- March 1992

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    The central equatorial Pacific typically has westward surface and near-surface flow, interrupted by periods of eastward flow. The processes that may have been responsible for two periods of eastward flow during the 1991-92 El Niño between October 1991 and March 1992 are explored here, based on realistic hindcasts from a high-vertical resolution ocean general circulation model. The model balances indicate that the November-December 1991 surface trapped jet is fully nonlinear, and both wind stress and horizontal pressure gradient forcing are significant. The January-February 1992 jet is less strongly nonlinear. Both jets are strongly affected by local and remote westerly wind event forcing. Linear dynamics are not consistent with the model balances. We note that the mid-November to early December 1991 jet plausibly created the vertical salinity gradient that was observed in late December 1991. Although this salinity gradient can contribute to the maintenance of a vertically sheared eastward flow, it does not appear to have been fundamental in the creation of the two jets observed during this period. Accurate sampling of this region during periods of high variability requires frequent measurements. Local dynamics arrays with high vertical resolution current profiles, from the surface to beneath the Equatorial Undercurrent, are critical to the advancement of our understanding of equatorial dynamics, to evaluating the skill of our numerical models, and to accurate simulation and state estimation for this fascinating area of the ocean

    Insulin prophylaxis down-regulates islet antigen expression and islet autoimmunity in the low-dose Stz mouse model of diabetes.

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    The aims of this study were to evaluate in an autoimmune diabetes animal model [low-dose streptozotocin (LD-STZ) mouse] (a) the efficacy of a prophylactic insulin treatment as a diabetes prevention tool, and (b) its possible mechanisms through both the insulitis evaluation and islets antigen expression. Diabetes was induced in male C57Bl6/J mice with STZ (50 mg/kg b/w for five consecutive days); insulin (1 U/day) was injected subcutaneously for ten consecutive days before the induction of diabetes and for a further ten days. Seventy-one male C57Bl6/J mice were grouped as follows: Group 1 (n = 25) made diabetic with i.p. STZ, Group 2 (n = 21) made diabetic with i.p. STZ and injected subcutaneously with insulin, Group 3 (n = 15) injected with insulin, while Group 4 (n = 10) comprised normal animals as controls. The animals of each group were killed at two intervals: half of them at day 12 and the remainder at day 24 from the beginning of the STZ treatment. A significant reduction of glycemia levels and insulitis severity was observed between mice of Group 1 vs. Group 2 at day 12 and day 24. Down-regulation of islet antigen expression (insulin, A2B5, GM2-1, ICA Ag) was achieved even without a complete metabolic suppression of beta-cell activity. In conclusion, prophylactic insulin treatment is effective to reduce glycemia levels and insulitis severity and down-regulates islet antigen expression in the LD-STZ model

    [Clinical and prognostic importance of changes in the number of circulating lymphocytes in cerebral infarction of the ischemic type].

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    Aim of the present study was to assess the increase of peripheral white blood cell (WBC) count and its clinical and prognostic significance in patients with cerebral ischemic infarction (CI). Thirty-six subjects (17 males, 19 females; mean age 73 +/- 10 years) with CI confirmed at CT scans were studied. A significant increase of WBC, not related to complicating infections, was observed in the early phase of CI. There was a significant linear correlation between the level of serum creatine phosphokinase and the number of circulating WBC which were higher in patients who died 6-30 days after the occurrence of CI. These data suggest that the increase in circulating WBC is dependent on the extent of the cerebral damage and should be considered as unfavourable prognostic sign

    Insulin prophylaxis down-regulates islet antigen expression and islet autoimmunity in the low-dose STZ mouse model of diabetes

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    The aims of this study were to evaluate in an autoimmune diabetes animal model [low-dose streptozotocin (LD-STZ) mouse] (a) the efficacy of a prophylactic insulin treatment as a diabetes prevention tool, and (b) its possible mechanisms through both the insulitis evaluation and islets antigen expression, Diabetes was induced in male C57B16/J mice with STZ (50 mg/kg b/w for five consecutive days); insulin (1 U/day) was injected subcutaneously for ten consecutive days before the induction of diabetes and for a further ten days. Seventy-one male C57B16/J mite were grouped as follows: Group I (n = 25) made diabetic with i,p, STZ, Group 2 (n = 21) made diabetic with i,p, STZ and injected subcutaneously with insulin, Group 3 (It = 15) injected with insulin, while Group 4 (n = 10) comprised normal animals as controls. The animals of each group were killed at two intervals: half of them at day 12 and the remainder at day 24 from the beginning of the STZ treatment. A significant reduction of glycemia levels and insulitis severity was observed between mice of Group 1 vs. Group 2 at day 12 and day 24, Down-regulation of islet antigen expression (insulin, A2B5, GM2-1, ICA Ag) was achieved even without a complete metabolic suppression of beta-cell activity. In conclusion, prophylactic insulin treatment is effective to reduce glycemia levels and insulitis severity and down-regulates islet antigen expression in the LD-STZ model

    [Plasma osteocalcin in children: effects of age, sex and body surface].

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    The aim of the study was the evaluation of plasma osteocalcin (O.), alkaline phosphatases (A.P.) and urinary hydroxyproline excretion (uOHPr) in subjects 3-20 years aged. O., A.F. and uOHPr were increased in patients less than 15 years aged; thereafter the values were similar to normal adult values. O. correlates with age and body surface area in children aged less than 15 years; the highest values were observed at the expected age of puberal spurt. This behaviour was not evident for the other bone turnover markers studied. In conclusion, it could be suggested that O. is a useful index of bone peak mass reached at puberty

    Anti-ganglioside antibodies in new onset type 1 diabetic patients and high risk subjects.

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    Insulin dependent (type 1) diabetes mellitus appears to be a genetically determined autoimmune disease. Gangliosides have been implicated in type 1 diabetes as antigenic determinants recognized by islet cell antibodies (ICA) and shown to be able to modulate autoimmune phenomena in experimental diabetes. In order to explore in type 1 diabetes the humoral immune reactivity against gangliosides, taking into account their pancreatic localization and molecular characteristics, antibodies to gangliosides GM3, GM2, GM1, GD3, GD1a, GD1b, and GT1b have been investigated in sera from new onset type 1 diabetics and relatives of type 1 diabetic patients with or without insulin (CIAA) and/or islet cell autoantibodies. Using a purposefully designed sensitive ELISA method we found that presence of antibodies directed against the pacreatic disialo-ganglioside GD3 in a significant percentage of newly diagnosed type 1 diabetics (p < 0.001 vs normal controls) but not in CIAA and/or ICA positive relatives of type 1 diabetics. These findings confirm the involvement of gangliosides in autoimmune phenomena related to type 1 diabetes and suggest disialo-ganglioside GD3 as target of a humoral immune response associated with the onset of insulin-dependent diabetes
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