517 research outputs found

    Transport of Mars-Crossing Asteroids from the Quasi-Hilda Region

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    We employ set oriented methods in combination with graph partitioning algorithms to identify key dynamical regions in the Sun-Jupiter-particle three-body system. Transport rates from a region near the 3:2 Hilda resonance into the realm of orbits crossing Mars' orbit are computed. In contrast to common numerical approaches, our technique does not depend on single long term simulations of the underlying model. Thus, our statistical results are particularly reliable since they are not affected by a dynamical behavior which is almost nonergodic (i.e., dominated by strongly almost invariant sets)

    Emergence of long memory in stock volatility from a modified Mike-Farmer model

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    The Mike-Farmer (MF) model was constructed empirically based on the continuous double auction mechanism in an order-driven market, which can successfully reproduce the cubic law of returns and the diffusive behavior of stock prices at the transaction level. However, the volatility (defined by absolute return) in the MF model does not show sound long memory. We propose a modified version of the MF model by including a new ingredient, that is, long memory in the aggressiveness (quantified by the relative prices) of incoming orders, which is an important stylized fact identified by analyzing the order flows of 23 liquid Chinese stocks. Long memory emerges in the volatility synthesized from the modified MF model with the DFA scaling exponent close to 0.76, and the cubic law of returns and the diffusive behavior of prices are also produced at the same time. We also find that the long memory of order signs has no impact on the long memory property of volatility, and the memory effect of order aggressiveness has little impact on the diffusiveness of stock prices.Comment: 6 pages, 6 figures and 1 tabl

    Quantum utility -- definition and assessment of a practical quantum advantage

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    Several benchmarks have been proposed to holistically measure quantum computing performance. While some have focused on the end user's perspective (e.g., in application-oriented benchmarks), the real industrial value taking into account the physical footprint of the quantum processor are not discussed. Different use-cases come with different requirements for size, weight, power consumption, or data privacy while demanding to surpass certain thresholds of fidelity, speed, problem size, or precision. This paper aims to incorporate these characteristics into a concept coined quantum utility, which demonstrates the effectiveness and practicality of quantum computers for various applications where quantum advantage -- defined as either being faster, more accurate, or demanding less energy -- is achieved over a classical machine of similar size, weight, and cost. To successively pursue quantum utility, a level-based classification scheme -- constituted as application readiness levels (ARLs) -- as well as extended classification labels are introduced. These are demonstratively applied to different quantum applications from the fields of quantum chemistry, quantum simulation, quantum machine learning, and data analysis followed by a brief discussion

    Infectious Causes of Acute and Chronic Sinusitis

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    Paranasal sinuses anatomy is paired in 4 parts which includes frontal, maxillary, ethmoid, and sphenoid. Their relevant function is to secrete mucous for moisture, humidify inspired air, impart vocal resonance, and act as shock absorber for intracranial contents. Retention of secretions in the nasal cavity and sinuses can cause inflammation of the mucosa of paranasal sinuses and lead to infection. Classification of sinusitis is based on duration of symptoms. Diagnosis can be achieved clinically, however other diagnosis modalities such as cultures or radiology can help to achieve accurate diagnosis. Depending on the etiology management can be supportive or pharmacological. In some cases, long term monitoring and prevention therapy may be required

    Magnetic Catalysis in AdS4

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    We study the formation of fermion condensates in Anti de Sitter space. In particular, we describe a novel version of magnetic catalysis that arises for fermions in asymptotically AdS4 geometries which cap off in the infra-red with a hard wall. We show that the presence of a magnetic field induces a fermion condensate in the bulk that spontaneously breaks CP symmetry. From the perspective of the dual boundary theory, this corresponds to a strongly coupled version of magnetic catalysis in d=2+1.Comment: 22 pages, 4 figures. v2: References added, factors of 2 corrected, extra comments added in appendix. v3: extra comments about fermion modes in a hard wall background. v4: A final factor of

    Structural and ultrastructural evaluation of the effects induced by IL-22 alone or in combination with psoriatic cytokines in an ex-vivo human skin model

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    L-22 is a pro-inflammatory cytokine playing a crucial role in the pathogenesis of psoriasis, an autoimmune chronic inflammatory skin disease. The immunological acti- vation during the progression of the psoriatic lesion is driven by IL-22 together with other cytokines, such as (TNF)-alpha and interleukin (IL)-17 [1]. The aim of our study was to evaluate the early, direct, and specific effect of IL-22 alone or in combination with TNF-alpha and IL-17 by immunofluorescence on i) the molecular composition of intercellular junctions (desmocollin (DSC)1, E-cadherin, and occludin), ii) keratin(K) 10 and 17 expression, iii) keratinocyte proliferation, and, by transmission electron micros- copy (TEM), on the ultrastructural morphology of the skin. An innovative model of human skin culture standardized in our laboratory, in which a psoriatic microenviron- ment was reproduced, was used [2]. Skin explants obtained from plastic surgery of healthy 20-40 year-old women (n = 7) after informed consent were cultured overnight in Dulbecco’s modified Eagle’s medium, divided before adding IL-22 or a combination of the three cytokines, and harvested 24, 48, and 72 hours after cytokine incubation.Interestingly, keratinocyte proliferation was inhibited after exposure to the combi- nation of cytokines while was not affected by IL-22 incubation. In both experimental groups, starting from T24, occludin immunostaining was non homogeneously distrib- uted, K10 immunostaining gradually decreased in scattered clusters in the spinous layer, while K17 expression was induced and progressively increased with time in the suprabasal layers of epidermis. By TEM, after IL-22 incubation we observed keratin aggregates in the perinuclear cytoplasm of cells, while the combination of the three cytokines induced an enlargement of intercellular spaces.Altogether, our results suggest that IL-22 mainly affects keratinocyte terminal dif- ferentiation, whereas, for inducing an impairment in cell proliferation, a more com- plex psoriatic-like microenvironment is needed.

    Baseline White Matter Hyperintensities and Hippocampal Volume are Associated With Conversion From Normal Cognition to Mild Cognitive Impairment in the Framingham Offspring Study.

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    INTRODUCTION: We examined associations between magnetic resonance imaging (MRI) markers of cerebrovascular disease and neurodegeneration with mild cognitive impairment (MCI) diagnosis at baseline and conversion from normal cognition to MCI at follow-up. METHODS: Framingham Offspring participants underwent brain MRI and neuropsychological assessment at baseline (n=1049) and follow-up (n=561). Participants were classified at baseline and at follow-up as cognitively normal or MCI using sensitive neuropsychological criteria. White matter hyperintensity (WMH) volume, covert brain infarcts, hippocampal volume, and total cerebral brain volume were quantified. RESULTS: Baseline measures of WMH and hippocampal volume were associated with MCI status cross-sectionally and also with conversion from normal cognition to MCI at 6.5-year follow-up. Annualized change rates in total cerebral brain volume and hippocampal volume were associated with conversion from normal cognition to MCI to follow-up. DISCUSSION: Baseline WMH and hippocampal volume are markers that are both associated with conversion from normal cognition to MCI, highlighting the role of both vascular lesions and neurodegeneration in MCI

    Evaluation of protective effect of Thymol on UVBinduced damage in an ex-vivo human skin tissue model: morphological analysis and genotoxic evaluations

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    insult, among which is the most important solar ultraviolet (UV) radiation (Bernerd et al., 2001). For this reason, the use of human skin tissue obtained from plastic aesthetic surgery represents a simple but efficient experimental approach to reproduce a physiological condition to test the early effects of an exogenous stimulus as UV radiation and the possibility of preventing or reducing the early epidermal effects. Normal human skin explants were obtained from healthy young non smoking women 20-40 years old (n=5) after informed consent and cultured epidermal side up at the air-liquid interface overnight in a Transwell system before treatment (Donetti et al., 2005; Bedoni et al., 2007). They were further divided in two groups: the first was exposed to UVB doses ranging from 0.24 J/cm2 to 0.72 J/cm2 and the other one pretreated for 1 h with Thymol (natural monoterpene phenol, 6.6 μM), before the UVB irradiation. In each experiment a cultured sample was not UVB exposed and represented the internal control. Samples were harvested 24 hours after of UVB exposure. Lactate Dehydrogenase (LDH) assay and alkaline comet and micronucleus tests were used to assess cytotoxicity and genotoxicity, respectively. Bioptic fragments were processed both for transmission electron (TEM) and light (LM) microscopy. Epidermal proliferation was investigated by indirect immunofluorescence after incorporation of 5-Bromo- 2’-deoxyuridine (BrdU). UVB induced evident ultrastructural alterations in nucleus and cytoskeleton, while the pretreatment with Thymol showed a reduction of damage in UVB exposed samples both from the morphological point of view that genotoxic aspects. Cell proliferation was strongly inhibited by UVB exposure, while in Thylom pretreated samples was comparable to control. Furthermore these results strongly support the use of ex vivo human skin as a relevant method for safety evaluation of UV skin exposure
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