921 research outputs found

    Metastatic Renal Cell Carcinoma to Submandibular Gland: A Rare Occurrence

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    Approximately 20-30% of patients affected by renal cell carcinoma (RCC) present with metastatic disease, and 20% to 40% undergoing nephrectomy for clinically localized disease will develop metastases. A 53 years old female patient developed a left submandibular swelling. Four years before she experienced a left radical nephrectomy for a clear cell tumor and two years later right kidney was removed for a cancer having the same histologic subtype. In that circumstance duodenal pancreasectomy was required for infiltration of pancreatic gland. A sialoadenectomy has been performed and pathology demonstrated an intraglandular neoplasm with characteristics of a clear renal cell carcinoma. Although it is extremely rare, submandibular salivary gland may be a site of RCC metastasis. Diagnosis of metastatic disease for patients affected by submandibular swelling with a previous history of RCC should be always considered

    Untangling perceptual memory: hysteresis and adaptation map into separate cortical networks

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    Perception is an active inferential process in which prior knowledge is combined with sensory input, the result of which determines the contents of awareness. Accordingly, previous experience is known to help the brain “decide” what to perceive. However, a critical aspect that has not been addressed is that previous experience can exert 2 opposing effects on perception: An attractive effect, sensitizing the brain to perceive the same again (hysteresis), or a repulsive effect, making it more likely to perceive something else (adaptation). We used functional magnetic resonance imaging and modeling to elucidate how the brain entertains these 2 opposing processes, and what determines the direction of such experience-dependent perceptual effects. We found that although affecting our perception concurrently, hysteresis and adaptation map into distinct cortical networks: a widespread network of higher-order visual and fronto-parietal areas was involved in perceptual stabilization, while adaptation was confined to early visual areas. This areal and hierarchical segregation may explain how the brain maintains the balance between exploiting redundancies and staying sensitive to new information. We provide a Bayesian model that accounts for the coexistence of hysteresis and adaptation by separating their causes into 2 distinct terms: Hysteresis alters the prior, whereas adaptation changes the sensory evidence (the likelihood function)

    Event boundaries shape temporal organization of memory by resetting temporal context

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    In memory, our continuous experiences are broken up into discrete events. Boundaries between events are known to influence the temporal organization of memory. However, how and through which mechanism event boundaries shape temporal order memory (TOM) remains unknown. Across four experiments, we show that event boundaries exert a dual role: improving TOM for items within an event and impairing TOM for items across events. Decreasing event length in a list enhances TOM, but only for items at earlier local event positions, an effect we term the local primacy effect. A computational model, in which items are associated to a temporal context signal that drifts over time but resets at boundaries captures all behavioural results. Our findings provide a unified algorithmic mechanism for understanding how and why event boundaries affect TOM, reconciling a long-standing paradox of why both contextual similarity and dissimilarity promote TOM

    Memory guidance of value-based decision making at an abstract level of representation

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    Value-based decisions about alternatives we have never experienced can be guided by associations between current choice options and memories of prior reward. A critical question is how similar memories need to be to the current situation to effectively guide decisions. We address this question in the context of associative learning of faces using a sensory preconditioning paradigm. We find that memories of reward spread along established associations between faces to guide decision making. While memory guidance is specific for associated facial identities, it does not only occur for the specific images that were originally encountered. Instead, memory guidance generalizes across different images of the associated identities. This suggests that memory guidance does not rely on a pictorial format of representation but on a higher, view-invariant level of abstraction. Thus, memory guidance operates on a level of representation that neither over- nor underspecifies associative relationships in the context of obtaining reward

    A variable delay integrated receiver for differential phase-shift keying optical transmission systems

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    An integrated variable delay receiver for DPSK optical transmission systems is presented. The device is realized in silicon-on-insulator technology and can be used to detect DPSK signals at any bit-rates between 10 and 15 Gbit/s

    Tunable delay lines in silicon photonics: coupled resonators and photonic crystals, a comparison

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    In this paper, we report a direct comparison between coupled resonator optical waveguides (CROWs) and photonic crystal waveguides (PhCWs), which have both been exploited as tunable delay lines. The two structures were fabricated on the same silicon-on-insulator (SOI) technological platform, with the same fabrication facilities and evaluated under the same signal bit-rate conditions. We compare the frequency- and time-domain response of the two structures; the physical mechanism underlying the tuning of the delay; the main limits induced by loss, dispersion, and structural disorder; and the impact of CROW and PhCW tunable delay lines on the transmission of data stream intensity and phase modulated up to 100 Gb/s. The main result of this study is that, in the considered domain of applications, CROWs and PhCWs behave much more similarly than one would expect. At data rates around 100 Gb/s, CROWs and PhCWs can be placed in competition. Lower data rates, where longer absolute delays are required and propagation loss becomes a critical issue, are the preferred domain of CROWs fabricated with large ring resonators, while at data rates in the terabit range, PhCWs remain the leading technology

    Low loss, high contrast optical waveguides based on CMOS compatible LPCVD processing

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    A new class of integrated optical waveguide structures is presented, based on low cost CMOS compatible LPCVD processing. This technology allows for medium and high index contrast waveguides with very low channel attenuation. The geometry is basically formed by a rectangular cross-section silicon nitride (Si3N4)(Si_{3}N_{4}) filled with and encapsulated by silicon dioxide (SiO2)(SiO_{2}). The birefringence and minimal bend radius of the waveguide is completely controlled by the geometry of the waveguide layer structures. Experiments on typical geometries will be presented, showing excellent characteristics (channel attenuation ≤0.06 dB/cm, IL ≤0.6 dB, PDL ≤0.2 dB, Bg «1 x 10310^{-3}, bend radius ≤500 μm)

    Untangling perceptual memory: Hysteresis and adaptation map into separate cortical networks

    Get PDF
    Perception is an active inferential process in which prior knowledge is combined with sensory input, the result of which determines the contents of awareness. Accordingly, previous experience is known to help the brain "decide" what to perceive. However, a critical aspect that has not been addressed is that previous experience can exert 2 opposing effects on perception: An attractive effect, sensitizing the brain to perceive the same again (hysteresis), or a repulsive effect, making it more likely to perceive something else (adaptation). We used functional magnetic resonance imaging and modeling to elucidate how the brain entertains these 2 opposing processes, and what determines the direction of such experience-dependent perceptual effects. We found that although affecting our perception concurrently, hysteresis and adaptation map into distinct cortical networks: a widespread network of higher-order visual and fronto-parietal areas was involved in perceptual stabilization, while adaptation was confined to early visual areas. This areal and hierarchical segregation may explain how the brain maintains the balance between exploiting redundancies and staying sensitive to new information. We provide a Bayesian model that accounts for the coexistence of hysteresis and adaptation by separating their causes into 2 distinct terms: Hysteresis alters the prior, whereas adaptation changes the sensory evidence (the likelihood function)

    Impression management strategies in the Letter to Shareholders: empirical evidence from Italian listed firms

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    The importance of the Letter to Shareholders (LS) as a form of corporate communication is well documented in the previous literature. However, existent contributions also suggest that LS are used opportunistically by firms as locus of Impression Management (IM) strategy, possibly because of their voluntary and unregulated nature. The aim of this study is to assess whatever Italian firms use LS to convey a manipulated view of firms\u2019 behaviour. In particular, the paper verifies if unprofitable firms adopt a biased language in the LS manipulating the textual characteristics of these letters. A manual content analysis and a multivariate statistical analysis are run analysing the disclosure offered in all the LS made available by Italian listed firms referring to year 2013. The key results show that firms tend to use biased language to obfuscate their weak achievements, thus demonstrating that firms adopt IM in their LS. The evidence has relevant implications as we show that LS cannot be considered informative but rather than as a communication strategy to advance corporate image
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