402 research outputs found

    STRATEGY MANAGEMENT IN A MULTI-AGENT SYSTEM USING NEURAL NETWORKS FOR INDUCTIVE AND EXPERIENCE-BASED LEARNING

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    Intelligent agents and multi-agent systems prove to be a promising paradigm for solving problems in a distributed, cooperative way. Neural networks are a classical solution for ensuring the learning ability of agents. In this paper, we analyse a multi-agent system where agents use different training algorithms and different topologies for their neural networks, which they use to solve classification and regression problems provided by a user. Out of the three training algorithms under investigation, Backpropagation, Quickprop and Rprop, the first demonstrates inferior performance to the other two when considered in isolation. However, by optimizing the strategy of accepting or rejecting tasks, Backpropagation agents succeed in outperforming the other types of agents in terms of the total utility gained. This strategy is learned also with a neural network, by processing the results of past experiences. Therefore, we show a way in which agents can use neural network models for both external purposes and internal ones.agents, learning, neural networks, strategy management multi-agent system.

    Phase-sensitive evidence for dx2-y2-pairing symmetry in the parent-structure high-Tc cuprate superconductor Sr1-xLaxCuO2

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    Even after 25 years of research the pairing mechanism and - at least for electron doped compounds - also the order parameter symmetry of the high transition temperature (high-Tc) cuprate superconductors is still under debate. One of the reasons is the complex crystal structure of most of these materials. An exception are the infinite layer (IL) compounds consisting essentially of CuO2 planes. Unfortunately, these materials are difficult to grow and, thus, there are only few experimental investigations. Recently, we succeeded in depositing high quality films of the electron doped IL compound Sr1-xLaxCuO2 (SLCO), with x approximately 0.15, and on the fabrication of well-defined grain boundary Josephson junctions (GBJs) based on such SLCO films. Here we report on a phase sensitive study of the superconducting order parameter based on GBJ SQUIDs from a SLCO film grown on a tetracrystal substrate. Our results show that also the parent structure of the high-Tc cuprates has dx2-y2-wave symmetry, which thus seems to be inherent to cuprate superconductivity.Comment: Submitted to PRL, 5 pages, 3 figures, supplementary information included (4 pages, 4 figures

    Laparoscopic adjustable gastric banding – should a second chance be given?

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    Background: Obesity is a chronic relapsing-remitting disease and a global pandemic, being associated with multiple comorbidities. Laparoscopic adjustable gastric banding (LAGB) is one of the safest surgical procedures used for the treatment of obesity, and even though its popularity has been decreasing over time, it still remains an option for a certain group of patients, producing considerable weight loss and improvement in obesity-associated comorbidities. Methods: The aim of this study was to evaluate the impact of weight loss following LAGB on obesity-associated comorbidities, and to identify factors that could predict better response to surgery, and patient sub-groups exhibiting greatest benefit. A total of 99 severely obese patients (81.2% women, mean age 44.19 ± 10.94 years, mean body mass index (BMI) 51.84 ± 8.77 kg/m2) underwent LAGB in a single institution. Results obtained 1, 2, and 5 years postoperatively were compared with the pre-operative values using SPPS software version 20. Results: A significant drop in BMI was recorded throughout the follow-up period, as well as in A1c and triglycerides, with greatest improvement seen 2 years after surgery (51.8 ± 8.7 kg/m2 vs 42.3 ± 9.2 kg/m2, p < 0.05, 55.5 ± 19.1 mmol/mol vs 45.8 ± 13.7 mmol/mol, p < 0.05, and 2.2 ± 1.7 mmol/l vs 1.5 ± 0.6 mmol/l). Better outcomes were seen in younger patients, with lower duration of diabetes before surgery, and lower pre-operative systolic blood pressure. Conclusions: Younger age, lower degree of obesity, and lower severity of comorbidities at the time of surgery can be important predictors of successful weight loss, making this group of patients the ideal candidates for LAGB

    Transmission electron microscopy on interface engineered superconducting thin films

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    Male obesity associated gonadal dysfunction and the role of bariatric surgery

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    Obesity is an ever growing pandemic and a prevalent problem among men of reproductive age that can both cause and exacerbate male-factor infertility by means of endocrine abnormalities, associated comorbidities, and direct effects on the precision and throughput of spermatogenesis. Robust epidemiologic, clinical, genetic, epigenetic, and preclinical data support these findings. Clinical studies on the impact of medically induced weight loss on serum testosterone concentrations and spermatogenesis is promising but may show differential and unsustainable results. In contrast, literature has demonstrated that weight loss after bariatric surgery is correlated with an increase in serum testosterone concentrations that is superior than that obtained with only lifestyle modifications, supporting a further metabolic benefit from surgery that may be specific to the male reproductive system. The data on sperm and semen parameters is controversial to date. Emerging evidence in the burgeoning field of genetics and epigenetics has demonstrated that paternal obesity can affect offspring metabolic and reproductive phenotypes by means of epigenetic reprogramming of spermatogonial stem cells. Understanding the impact of this reprogramming is critical to a comprehensive view of the impact of obesity on subsequent generations. Furthermore, conveying the potential impact of these lifestyle changes on future progeny can serve as a powerful tool for obese men to modify their behavior. Healthcare professionals treating male infertility and obesity need to adapt their practice to assimilate these new findings to better counsel men about the importance of paternal preconception health and the impact of novel non-medical therapeutic interventions. Herein, we summarize the pathophysiology of obesity on the male reproductive system and emerging evidence regarding the potential role of bariatric surgery as treatment of male obesity-associated gonadal dysfunction

    Diagnosis and management of parathyroid carcinoma: a state-of-the-art review

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    Parathyroid carcinoma is one of the least common endocrine malignancies and accounts for approximately 1% of all patients with primary hyperparathyroidism. A systematic review of peer-reviewed literature published between January 2000 and March 2022 via Medline, Embase, Cochrane Central Register of Controlled Trials, EudraCT, ClinicalTrials.gov, CINAHL and SCOPUS was conducted. Manuscripts were eligible if they included data on adult non-pregnant populations with parathyroid carcinoma. No restrictions regarding interventions, comparators or duration of follow-up were imposed. Single case reports, reviews or meta-analyses were excluded. Outcomes of interest were molecular pathogenesis, clinical presentation, differential diagnosis, treatment, follow-up and overall survival. Study quality was evaluated using the Newcastle-Ottawa Scale for observational studies. This review included 75 studies from 17 countries, reporting on more than 3000 patients with parathyroid carcinoma. CDC73 mutation has been recognised as playing a pivotal role in molecular pathogenesis. Parathyroid carcinoma typically presents with markedly increased calcium and parathyroid hormone levels. The most frequently described symptoms were bone and muscle pain or weakness. En bloc resection remains the gold standard for the surgical approach. The 5-year overall survival ranged from 60 to 93%, with resistant hypercalcaemia a significant cause of mortality. Emerging evidence indicating that targeted therapy, based on molecular biomarkers, presents a novel treatment option. The rarity of PC and need for personalised treatment warrant multidisciplinary management in a 'centre of excellence' with a track record in PC management

    Entrepreneurial sons, patriarchy and the Colonels' experiment in Thessaly, rural Greece

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    Existing studies within the field of institutional entrepreneurship explore how entrepreneurs influence change in economic institutions. This paper turns the attention of scholarly inquiry on the antecedents of deinstitutionalization and more specifically, the influence of entrepreneurship in shaping social institutions such as patriarchy. The paper draws from the findings of ethnographic work in two Greek lowland village communities during the military Dictatorship (1967–1974). Paradoxically this era associated with the spread of mechanization, cheap credit, revaluation of labour and clear means-ends relations, signalled entrepreneurial sons’ individuated dissent and activism who were now able to question the Patriarch’s authority, recognize opportunities and act as unintentional agents of deinstitutionalization. A ‘different’ model of institutional change is presented here, where politics intersects with entrepreneurs, in changing social institutions. This model discusses the external drivers of institutional atrophy and how handling dissensus (and its varieties over historical time) is instrumental in enabling institutional entrepreneurship

    Cumulative culture in nonhumans : overlooked findings from Japanese monkeys?

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    The authors thank Corpus Christi College (Cambridge) for funding DS’s visit to Koshima and Prof. Tetsuro Matsuzawa for funding WCM’s visit to Koshima.Cumulative culture, generally known as the increasing complexity or efficiency of cultural behaviors additively transmitted over successive generations, has been emphasized as a hallmark of human evolution. Recently, reviews of candidates for cumulative culture in nonhuman species have claimed that only humans have cumulative culture. Here, we aim to scrutinize this claim, using current criteria for cumulative culture to re-evaluate overlooked qualitative but longitudinal data from a nonhuman primate, the Japanese monkey (Macaca fuscata). We review over 60 years of Japanese ethnography of Koshima monkeys, which indicate that food-washing behaviors (e.g., of sweet potato tubers and wheat grains) seem to have increased in complexity and efficiency over time. Our reassessment of the Koshima ethnography is preliminary and nonquantitative, but it raises the possibility that cumulative culture, at least in a simple form, occurs spontaneously and adaptively in other primates and nonhumans in nature.Publisher PDFPeer reviewe

    (B)ordering South of Lebanon: Hizbullah’s identity building strategy

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    International audienceThis paper examines the importance of the Lebanese southern borderland area in the political strategy of Hizbullah's identity building. It highlights how Hizbullah succeeded in its quest to become a major political player in Lebanon by using South Lebanon. The main hypothesis is that this borderland area has been ordered and bordered by Hizbullah to create a common identity among the Lebanese Shi'i population based on a Shi'i religious involvement and the " duty " of armed resistance against Israel. To support this idea, I will rely on a theoretical framework articulating space and identity building and will refer to concepts provided by Middle Eastern studies. In the first part of the paper, I will discuss the conditions of the emergence of the group of solidarity and how it articulates to the religious Shi'i ideology. Then, I will highlight the " lebanonization " process Hizbullah undertaken at the end of the civil war and how during the 1990s it transformed the South into a sanctuary. Finally, I will show how Hizbullah enforced the national legitimacy of its social, political and military actions before targeting the state apparatus

    Retinol-binding protein 4 (RBP4) circulating levels and gestational diabetes mellitus:a systematic review and meta-analysis

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    Background: Gestational diabetes mellitus (GDM) is a prevalent condition where diabetes is diagnosed during pregnancy, affecting both maternal and fetal outcomes. Retinol-binding protein 4 (RBP4) is a circulating adipokine which belongs to the lipocalin family and acts as a specific carrier protein that delivers retinol (vitamin A) from the liver to the peripheral tissues. Growing data indicate that circulating RBP4 levels may positively correlate with GDM. Thus, this systematic review and meta-analysis aimed to investigate the potential relationship between circulating RBP4 levels and GDM when measured at various stages of pregnancy. Methods: MEDLINE, CINAHL, EMCARE, EMBASE, Scopus, and Web of Science databases were searched to identify studies comparing pregnant women with and without GDM, whose circulating RBP4 levels were measured in at least one pregnancy trimester. Findings were reported using standardized mean difference (SMD) and random-effects models were used to account for variability among studies. Furthermore, the risk of bias was assessed using the RoBANS tool. Results: Out of the 34 studies identified, 32 were included in the meta-analysis (seven with circulating RBP4 levels measured in the first trimester, 19 at 24–28 weeks, and 14 at >28 weeks of pregnancy). RBP4 levels were statistically higher in the GDM group than in controls when measured during all these pregnancy stages, with the noted RBP4 SMD being 0.322 in the first trimester (95% CI: 0.126–0.517; p 28 weeks of gestation (95% CI: 0.252–1.498; p = 0.006; 870 GDM cases vs. 1942 non-GDM controls). Significant study heterogeneity was noted for all three pregnancy timepoints. Conclusion: The present findings indicate consistently higher circulating RBP4 levels in GDM cases compared to non-GDM controls, suggesting the potential relevance of RBP4 as a biomarker for GDM. However, the documented substantial study heterogeneity, alongside imprecision in effect estimates, underscores the need for further research and standardization of measurement methods to elucidate whether RBP4 can be utilized in clinical practice as a potential GDM biomarker. Systematic review registration: PROSPERO (CRD42022340097: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022340097)
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