26,953 research outputs found

    The width-flux relation of the broad iron line during the state transition of the black hole X-ray binaries

    Full text link
    The observation of varying broad iron lines during the state transition of the black hole X-ray binaries (BHXBs) have been accumulating.In this work, the relation between the normalized intensity and the width of iron lines is investigated, in order to understand better the variation of iron lines and possibly its connection to state transition. Considering the uncertainties due to ionization and illuminating X-rays, only the effects of geometry and gravity are taken into account. Three scenarios were studied, i.e., the continuous disk model, innermost annulus model, and the cloud model. As shown by our calculations, at given iron width, the line flux of the cloud model is smaller than that of the continuous disk model; while for the innermost annulus model, the width is almost unrelated with the flux. The range of the line strength depends on both the BH spin and the inclination of the disk. We then apply to the observation of MAXI J1631-479 by NuSTAR during its decay from the soft state to the intermediate state. We estimated the relative line strength and width according to the spectral fitting results by Xu et al.(2020), and then compared with our theoretical width-flux relation. It was found that the cloud model was more favored. We further modeled the iron line profiles, and found that the cloud model can explain both the line profile and its variation with reasonable parameters.Comment: 7 figures, 12 pages, accepted for publication in RA

    Tonelli Approach to Lebesgue Integration

    Full text link
    Leonida Tonelli devised an interesting and efficient method to introduce the Lebesgue integral. The details of this method can only be found in the original Tonelli paper and in an old italian course and solely for the case of the functions of one variable. We believe that it is woth knowing this method and here we present a complete account for functions of every number of variables

    Biological effects of sub-lethal doses of glyphosate and AMPA on cardiac myoblasts

    Get PDF
    Introduction: Glyphosate is the active compound of different non-selective herbicides, being the most used agriculture pesticide worldwide. Glyphosate and AMPA (one of its main metabolites) are common pollutants of water, soil, and food sources such as crops. They can be detected in biological samples from both exposed workers and general population. Despite glyphosate acts as inhibitor of the shikimate pathway, present only in plants and some microorganisms, its safety in mammals is still debated. Acute glyphosate intoxications are correlated to cardiovascular/neuronal damages, but little is known about the effects of the chronic exposure.Methods: We evaluated the direct biological effects of different concentrations of pure glyphosate/AMPA on a rat-derived cell line of cardiomyoblasts (H9c2) in acute (1–2 h) or sub-chronic (24–48 h) settings. We analyzed cell viability/morphology, ROS production and mitochondrial dynamics.Results: Acute exposure to high doses (above 10 mM) of glyphosate and AMPA triggers immediate cytotoxic effects: reduction in cell viability, increased ROS production, morphological alterations and mitochondrial function. When exposed to lower glyphosate concentrations (1 μM—1 mM), H9c2 cells showed only a slight variation in cell viability and ROS production, while mitochondrial dynamic was unvaried. Moreover, the phenotype was completely restored after 48 h of treatment. Surprisingly, the sub-chronic (48 h) treatment with low concentrations (1 μM—1 mM) of AMPA led to a late cytotoxic response, reflected in a reduction in H9c2 viability.Conclusion: The comprehension of the extent of human exposure to these molecules remains pivotal to have a better critical view of the available data

    Refined EnE_n Chern-Simons theory

    Full text link
    The partition function of refined Chern-Simons theory on 3d sphere for the exceptional EnE_n gauge algebras is presented in terms of multiple sine functions. Gopakumar-Vafa (BPS) approximation is calculated and presented in the form of some refined topological string partition function.Comment: On the basis of the talk given at the workshop SQS'2

    On real and observable realizations of input-output equations

    Full text link
    Given a single algebraic input-output equation, we present a method for finding different representations of the associated system in the form of rational realizations; these are dynamical systems with rational right-hand sides. It has been shown that in the case where the input-output equation is of order one, rational realizations can be computed, if they exist. In this work, we focus first on the existence and actual computation of the so-called observable rational realizations, and secondly on rational realizations with real coefficients. The study of observable realizations allows to find every rational realization of a given first order input-output equation, and the necessary field extensions in this process. We show that for first order input-output equations the existence of a rational realization is equivalent to the existence of an observable rational realization. Moreover, we give a criterion to decide the existence of real rational realizations. The computation of observable and real realizations of first order input-output equations is fully algorithmic. We also present partial results for the case of higher order input-output equations

    Axially overlapped multi-focus light sheet with enlarged field of view

    Full text link
    Light sheet fluorescence microscopy provides optical sectioning and is widely used in volumetric imaging of large specimens. However, the axial resolution and the lateral Field of View (FoV) of the system, defined by the light sheet, typically limit each other due to the spatial band product of the excitation objective. Here, we develop a simple multi-focus scheme to extend the FoV, where a Gaussian light sheet can be focused at three or more consecutive positions. Axially overlapped multiple light sheets significantly enlarge the FoV with improved uniformity and negligible loss in axial resolution. By measuring the point spread function of fluorescent beads, we demonstrated that the obtained light sheet has a FoV of 450 μm and a maximum axial FWHM of 7.5 μm. Compared with the conventional single-focus one, the multi-focus Gaussian light sheet displays a significantly improved optical sectioning ability over the full FoV when imaging cells and zebrafish. Light sheet fluorescence microscopy (LSFM) has become an indispensable tool in volumetric imaging, with the advances in high spatiotemporal resolution and low photo-toxicity to the fluorescent sample. The open-source design with detailed instructions encourages DIY setups, which has significantly accelerated the wide-range adoption and applications of LSFM. Pioneering works, including OpenSPIM,1 OpenSpin,2 and the recent mesoSPIM,3 provide detailed protocols for building and using the microscopes. These joint efforts further allow the biology labs to build their LSFM system for a specific application, including more complex schemes, such as multiview excitation or detection configurations.4

    DataProVe: Fully Automated Conformance Verification Between Data Protection Policies and System Architectures

    Get PDF
    Privacy and data protection by design are relevant parts of the General Data Protection Regulation (GDPR), in which businesses and organisations are encouraged to implement measures at an early stage of the system design phase to fulfil data protection requirements. This paper addresses the policy and system architecture design and propose two variants of privacy policy language and architecture description language, respectively, for specifying and verifying data protection and privacy requirements. In addition, we develop a fully automated algorithm based on logic, for verifying three types of conformance relations (privacy, data protection, and functional conformance) between a policy and an architecture specified in our languages’ variants. Compared to related works, this approach supports a more systematic and fine-grained analysis of the privacy, data protection, and functional properties of a system. Our theoretical methods are then implemented as a software tool called DataProVe and its feasibility is demonstrated based on the centralised and decentralised approaches of COVID-19 contact tracing applications

    Exposure to early childhood maltreatment and its effect over time on social cognition

    Get PDF
    Social cognitive deficits can have many negative consequences, spanning social withdrawal to psychopathology. Prior work has shown that child maltreatment may associate with poorer social cognitive skills in later life. However, no studies have examined this association from early childhood into adolescence. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC; n = 4,438), we examined the association between maltreatment (caregiver physical or emotional abuse; sexual or physical abuse), assessed repeatedly (every 1-3 years) from birth to age 9, and social cognitive skills at ages 7.5, 10.5, and 14 years. We evaluated the role of both the developmental timing (defined by age at exposure) and accumulation of maltreatment (defined as the number of occasions exposed) using a least angle regression variable selection procedure, followed by structural equation modeling. Among females, accumulation of maltreatment explained the most variation in social cognitive skills. For males, no significant associations were found. These findings underscore the importance of early intervention to minimize the accumulation of maltreatment and showcase the importance of prospective studies to understand the development of social cognition over time

    Stratigraphy, chronology, and correlation of the Plio-Pleistocene (c. 2.2-0.8 Ma) Kauroa Ash sequence, western central North Island, New Zealand

    Get PDF
    The Kauroa Ash beds (K-beds) comprise a 12-20 m-thick sequence of extremely weathered, clay-rich (40-95% <4 μm clay) beds of tephra and loess, and associated paleosols. Found in isolated remnants throughout the western central North Island, the sequence comprises 15 defined members, with as many as 44 constituent macroscopic beds. The type site, ‘Woodstock’, near Raglan, is the most comprehensive sequence known, but other sites (e.g. Papakura Creek and Tiritirimatangi Peninsula) contain units not found or poorly defined at Woodstock. Field properties as well as magnetic susceptibility measurements and particle-size analysis characterise the facies in the sequence. Field properties (in particular colour, consistence, macrofabric) describe the lithostratigraphy. The sequence contains five interpretive (i.e. genetic) ‘facies’: paleosols, primary tephra, very weathered tephra (possibly composite beds), loess and ‘tephric loess’ beds. At least seven loess beds are (newly) identified in the sequence: K4a, K5, K6ai, K8ai, K8bi, K10a and K14ai. Mass-specific susceptibility and frequency-dependent susceptibility results partly conform to established models (developed mostly on Chinese loess-paleosol deposits) of susceptibility enhancement in paleosols and depletion in loess. Many parts of the sequence do not appear to conform to this model and the results more closely resemble the inverse relationship found on Alaskan loess-paleosol beds. Frequency-dependent susceptibility is reliable in delineating paleosols by their ‘ultrafine’ ferrimagnetic mineral content, and citrate-bicarbonate-dithionite treatments successfully remove all iron oxides so that remeasurement of susceptibility isolates a strictly ‘pedogenic’, rather than lithogenic, fraction. Laser diffraction particle-size analysis shows that the Kauroa Ash beds are texturally reasonably homogenous. They have bimodal particle-size distributions with the most dominant mode at around 11.25 ɸ inferred to be the product of intense and prolonged weathering. Other modes are variously centred on 7-8.5 ɸ and, despite weathering and pedogenesis, have some relationship to the original depositional particle-size distributions because trends between facies (i.e. genetic units) are delineated. Principal components analysis objectively characterises these modes as (Wentworth size classes) ‘very fine clay’ and ‘coarse silt’, although there is no proportional relationship between them, supporting a post-depositional origin for the former mode. The chronology of the sequence, previously poorly defined, is greatly improved by a combination of tephrochronologic correlations, fission-track dating, and paleomagnetism. Five zircon fission-track dates provide independent age ‘spikes’ and range from 2.24 ± 0.29 Ma in the basal member, K1, to 1.28 ± 0.11 Ma for the distal ignimbrite unit K12a. Paleomagnetism is invaluable in providing additional age information. The top of the sequence, member K15, is dated as >0.78 Ma (Brunhes-Matuyama boundary) because of its reversed polarity; two episodes of normal polarity are found in beds K14b and K2b and are inferred to represent the Jaramillo (1.07-0.99 Ma) and Olduvai (1.95-1.79 Ma) subchrons, respectively. Beds underlying the Kauroa Ash sequence are also of normal polarity, indicating that they were deposited in the Gauss Chron (>2.6 Ma). Identification and correlation of tephras by conventional means (fingerprinting by their lithological or geochemical properties) is impossible in the Kauroa Ash sequence because the beds have no remaining volcanic glass, which has instead been altered to an assemblage of authigenic phases (clays) by weathering and pedogenesis. However, a new technique analysing fresh glass found as melt inclusions in quartz grains is successful in circumventing this problem. Inclusions represent samples of non-degassed magma that became entrapped during phenocryst growth prior to eruption. The glass has remained unaltered because it is hermetically sealed in a chemically resistant phenocryst, which has protected it from weathering processes. Electron microprobe analysis of the glass inclusions yield results which are wholly reasonable for glass (totals ranging from 93-97%; low standard deviations of <1 %), and a number of provisional correlations are established by comparing the major element composition of Kauroa Ash tephra beds with those of proximal deposits. The Kauroa Ash sequence may contain deposits correlated with at least seven major TVZ eruptions, in many cases expanding the known extent of the (distal) deposit and, for the first time answering the question as to the origin of the Kauroa Ash beds. These correlations, together with an improved chronology, enable the Kauroa Ash sequence to be placed in a regional stratigraphic framework alongside other New Zealand Plio-Pleistocene sequences such as those in the Wanganui Basin, Wairarapa, Cape Kidnappers and Port Waikato. Using paleosols as chrono- and climatostratigraphic entities (correlated to warm periods in global climate), the sequence can also be placed alongside a global reference, the marine oxygen isotope stratigraphy. A further correlation to the Chinese loess-paleosol record suggests that large parts of the Kauroa Ash sequence were deposited in an incremental manner akin to deposition of loess, so that the sequence is not only a record of TVZ volcanism, but also of Plio-Pleistocene paleoclimate
    corecore