159 research outputs found

    Obstacle Avoidance by Means of an Operant Conditioning Model

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    This paper describes the application of a model of operant conditioning to the problem of obstacle avoidance with a wheeled mobile robot. The main characteristic of the applied model is that the robot learns to avoid obstacles through a learning-by-doing cycle without external supervision. A series of ultrasonic sensors act as Conditioned Stimuli (CS), while collisions act as an Unconditioned Stimulus (UCS). By experiencing a series of movements in a cluttered environment, the robot learns to avoid sensor activation patterns that predict collisions, thereby learning to avoid obstacles. Learning generalizes to arbitrary cluttered environments. In this work we describe our initial implementation using a computer simulation

    Optical Interconnection Architectures based on Microring Resonators

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    Abstract: Microring resonators are an interesting device to build integrated optical interconnects, but their asymmetric loss behavior could limit the scalability of classical optical interconnects. We present new interconnects able to increase scalability with limited complexity

    Optical Interconnection Networks Based on Microring Resonators

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    Abstract — Interconnection networks must transport an always increasing information density and connect a rising number of processing units. Electronic technologies have been able to sustain the traffic growth rate, but are getting close to their physical limits. In this context, optical interconnection networks are becoming progressively more attractive, especially because new photonic devices can be directly integrated in CMOS technology. Indeed, interest in microring resonators as switching components is rising, but their usability in full optical interconnection architectures is still limited by their physical characteristics. Indeed, differently from classical devices used for switching, switching elements based on microring resonators exhibit asymmetric power losses depending on the output ports input signals are directed to. In this paper, we study classical interconnection architectures such as crossbar, Benes and Clos networks exploiting microring resonators as building blocks. Since classical interconnection networks lack either scalability or complexity, we propose two new architectures to improve performance of microring based interconnection networks while keeping a reasonable complexity. I

    Does the risk of arterial hypertension increase in the course of triptorelin treatment?

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    Gonadotropin-releasing hormone agonists (GnRH-a) are common treatment options for central precocious puberty (CPP) in childhood. GnRH-a treatment is useful and has a good safety profile, with minimal adverse effects and no severe long-term consequences. The common side effects in children are menopause-like symptoms and local adverse events at the injection site

    Central precocious puberty in a girl with LEGIUS syndrome: an accidental association?

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    BACKGROUND: Central precocious puberty is a condition characterized by precocious activation of the hypothalamic-pituitary-gonadal axis. It may be idiopathic or secondary to organic causes, including syndromes such as Neurofibromatosis type 1 (NF1).CASE PRESENTATION: We presented a girl of 6years and 10months with almost 11 cafe-au-lait skin macules, without other clinical or radiological signs typical of NF1, and with a central precocious puberty. Genetic analysis evidenced the new variant NM-152594.2:c.304delAp. (Thr102Argfs*19) in SPRED1 gene, which allowed to diagnose Legius syndrome.CONCLUSIONS: We report for the first time a case of central precocious puberty in a girl with Legius syndrome. The presence of central precocious puberty in a child with characteristic cafe-au-lait macules should suggest pediatricians to perform genetic analysis in order to reach a definitive diagnosis. Further studies on timing of puberty in patients with RASopathies are needed to better elucidate if this clinical association is casual or secondary to their clinical condition

    DYSMORPHIC features and adult short stature: possible clinical markers of KBG syndrome

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    BackgroundGrowth monitoring is an essential part of primary health care in children and short stature is frequently regarded as a relatively early sign of poor health. The association of short stature and dysmorphic features should always lead to exclude an underlying syndromic disorder.Case presentationWe report the case of an Indian school-aged boy with dysmorphic features, intellectual disability and a clinical history characterized by seizures and hearing problems. Although his height was always included in the normal range for age and sex throughout childhood, he presented a short near-adult stature in relation to his mid-parent sex-adjusted target height. This is probably due to a rapidly progressive pubertal development.ConclusionsIn the presence of characteristic dysmorphic features, intellectual disability, seizures and hearing problems, KBG syndrome should always be considered. This emergent condition presents a wide spectrum of clinical phenotypes and is often associated with adult short stature

    CONSTITUTIVE ACTIVATION OF THE RON GENE INDUCES INVASIVE GROWTH BUT NOT TRANSFORMATION

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    Hepatocyte growth factor (HGF) receptor expression is inducible and is part of the delayed-early response to HGF.

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    The c-MET proto-oncogene encodes the tyrosine kinase receptor for hepatocyte growth factor (HGF), also known as scatter factor, a potent mitogen and motogen for epithelial cells. The level of the HGF receptor expressed by epithelial cells varies in different growth conditions, being lower in growth arrested confluent monolayers and higher in growing sparse cells. The amount of HGF receptor mRNA increases from 3- to 5-fold after stimulation of confluent monolayers by serum and up to 10-fold after stimulation of protein kinase C by 12-O-tetradecanoylphorbol-13-acetate (TPA). An increased level of the receptor mRNA was also observed after cell stimulation with nanomolar concentration of HGF itself. The effect was transient, dose, and time-dependent. Transcription of a reporter gene under control of the cloned 297 base pair c-MET promoter was also stimulated by serum, TPA, or HGF. The accumulation of specific mRNA is followed by appearance of the HGF receptor precursor protein, which is further processed to the receptor mature form. After HGF stimulation, HGF receptor expression follows c-FOS and c-JUN induction with a peak approximately 4 h. Pretreatment with the protein synthesis inhibitor puromycin strongly reduced the response to HGF, while cycloheximide alone increased the level of the receptor mRNA. These data show that c-MET behaves as a delayed early-response gene and suggest that the HGF response is autoamplified by inducing the specific receptor

    Phenotypic Overlap in Children with Tall Stature: A Case of Weaver Syndrome

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    Introduction: Tall stature is defined as length or height more than two standard deviations above the mean for age of the refer- ence population. There are different causes of tall stature from a familial trait or a transient anticipation of growth with no major consequences to growth disorders, such as endocrine disorder and syndromic conditions like overgrowth syndromes. Case Presentation: In this study, we reported the case of a 7-year-old girl with tall stature from birth. The patient showed a general- ized overgrowth, associated with extremely advanced bone age, dysmorphic features such as a broad forehead and large extremities, and a slight neurodevelopmental delay. Laboratory tests were normal, and the main hormonal disorders were ruled out. The diag- nosis of overgrowth syndrome was suspected according to the clinical presentation, and the diagnosis of Weaver syndrome was confirmed by the finding of the pathogenic mutation c.2050C > T p.(Arg684Cys) in EZH2 gene through next generation sequencing (NGS). Conclusions: Our patient showed phenotypical features related to different overgrowth syndrome characteristics. We underlined the difficulties in reaching a clinical diagnosis in presence of tall stature. The role of molecular biology, particularly genetic analysis by NGS approach, should be considered in cases of tall stature with phenotypic overlap
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