859 research outputs found

    Central band interosseus membrane reconstruction for longitudinal instability injuries of the forearm

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    Aims Acute and chronic injuries of the interosseus membrane can result in longitudinal instability of the forearm. Reconstruction of the central band of the interosseus membrane can help to restore biomechanical stability. Different methods have been used to reconstruct the central band, including tendon grafts, bone-ligament-bone grafts, and synthetic grafts. This Idea, Development, Exploration, Assessment, and Long-term (IDEAL) phase 1 study aims to review the clinical results of reconstruction using a synthetic braided cross-linked graft secured at either end with an Endobutton to restore the force balance between the bones of the forearm. Methods An independent retrospective review was conducted of a consecutive series of 21 patients with longitudinal instability injuries treated with anatomical central band reconstruction between February 2011 and July 2019. Patients with less than 12 months’ follow-up or who were treated acutely were excluded, leaving 18 patients in total. Preoperative clinical and radiological assessments were compared with prospectively gathered data using range of motion and the abbreviated version of the Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH) functional outcome score. Results Of the 18 patients (nine male, nine female) who met the inclusion criteria, the median follow-up was 8.5 years (interquartile range (IQR) 5.6 to 10). Their mean age was 49 years (SD 11). The mean extension improved significantly from 38° (SD 15°) to 24° (SD 9°) (p = 0.027), with a mean flexion-extension arc change from 81° (SD 27°) to 93° (SD 30°) (p = 0.172) but with no forearm rotational improvement (p = 0.233) at latest follow-up. The QuickDASH functional score improved significantly from 80 (SD 14) to 52 (SD 26) following reconstruction (p = 0.031), but generally the level of disability remains high. Radiological assessment showed no progression of proximal migration of the radius, with a stable interbutton distance and ulnar variance from immediate postoperative radiograph to the latest follow-up. Conclusion Central band interosseus membrane reconstruction using a synthetic braided cross-linked graft can improve patient-rated arm function and range of motion, but significant functional deficits remain in patients with chronic injuries.</p

    Bound on the multiplicity of almost complete intersections

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    Let RR be a polynomial ring over a field of characteristic zero and let IRI \subset R be a graded ideal of height NN which is minimally generated by N+1N+1 homogeneous polynomials. If I=(f1,...,fN+1)I=(f_1,...,f_{N+1}) where fif_i has degree did_i and (f1,...,fN)(f_1,...,f_N) has height NN, then the multiplicity of R/IR/I is bounded above by i=1Ndimax{1,i=1N(di1)(dN+11)}\prod_{i=1}^N d_i - \max\{1, \sum_{i=1}^N (d_i-1) - (d_{N+1}-1) \}.Comment: 7 pages; to appear in Communications in Algebr

    On Dijkgraaf-Witten Type Invariants

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    We explicitly construct a series of lattice models based upon the gauge group ZpZ_{p} which have the property of subdivision invariance, when the coupling parameter is quantized and the field configurations are restricted to satisfy a type of mod-pp flatness condition. The simplest model of this type yields the Dijkgraaf-Witten invariant of a 33-manifold and is based upon a single link, or 11-simplex, field. Depending upon the manifold's dimension, other models may have more than one species of field variable, and these may be based on higher dimensional simplices.Comment: 18 page

    Молодежь современной Беларуси: базовые ценности, жизненные планы и поведенческие стратегии

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    The article considers the transformation of basic values, life plans and behavioral strategies of the youth in contemporary Belarus. The changes in basic values are directly connected with the youth's adaptation to the conditions of global instability. The new generation is sensitive to social injustice, violations of rights and freedoms, unwillingness to take into account their opinions on current issues of social development and the future. The self-perception of people regarding the possibility to realize basic values in the current social-economic conditions is an important factor of social stability. In both 1990 and 2018, family holds the first place among the basic values in Belarus; work takes the second place as a factor of decent life and family's success; the importance of friends and leisure remains the same over the decades, while the importance of politics and religion grows. International comparisons show that Belarus has the same hierarchy of values as European countries. The surveys prove a decrease in popularity of the traditional media among the youth and an increase in individualism, importance of personal self-realization in family and at work, and in reliance on one’s own forces. In the public space, the needs and expectations of people have changed - there is an increase in political radicalization and critical perception of the most important events, which affects the behavioral patterns of social-demographic groups. Education together with the family and new information technologies have a significant impact on values - there is an intragenerational gap, alienation from society and increasing informatization. The article is based on the results of the sociological surveys conducted in the framework of the European Values Study (EVS) (the results of 1990 and 2018 are compared)

    Quantum walks on quotient graphs

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    A discrete-time quantum walk on a graph is the repeated application of a unitary evolution operator to a Hilbert space corresponding to the graph. If this unitary evolution operator has an associated group of symmetries, then for certain initial states the walk will be confined to a subspace of the original Hilbert space. Symmetries of the original graph, given by its automorphism group, can be inherited by the evolution operator. We show that a quantum walk confined to the subspace corresponding to this symmetry group can be seen as a different quantum walk on a smaller quotient graph. We give an explicit construction of the quotient graph for any subgroup of the automorphism group and illustrate it with examples. The automorphisms of the quotient graph which are inherited from the original graph are the original automorphism group modulo the subgroup used to construct it. We then analyze the behavior of hitting times on quotient graphs. Hitting time is the average time it takes a walk to reach a given final vertex from a given initial vertex. It has been shown in earlier work [Phys. Rev. A {\bf 74}, 042334 (2006)] that the hitting time can be infinite. We give a condition which determines whether the quotient graph has infinite hitting times given that they exist in the original graph. We apply this condition for the examples discussed and determine which quotient graphs have infinite hitting times. All known examples of quantum walks with fast hitting times correspond to systems with quotient graphs much smaller than the original graph; we conjecture that the existence of a small quotient graph with finite hitting times is necessary for a walk to exhibit a quantum speed-up.Comment: 18 pages, 7 figures in EPS forma

    Белорусское общество: от ценностей выживания к ценностям развития и самовыражения

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    The article considers new trends in the value system of the Belarusian society. Based on the data of the international sociological surveys conducted as waves of the European Values Study and World Values Study, the authors identify changes in the value orientations of the Belarusian society over the past thirty years. The authors use the methodological approach to identifying the system of value orientations that was developed by R. Inglehart and K. Welzel. The study of fundamental trends in the changing value world of the contemporary society is of practical importance for understanding internal factors of the current socialpolitical processes and for assessing prospects for the further sustainable development of socialpolitical institutions. The article aims at identifying the main directions in the transformation of the value orientations of the Belarusian society since the acquisition of state sovereignty. The authors conclude that the Belarusian society moves from the values of survival to the values of development and self-expression. In the project, the authors conducted an analysis of the demographic structure of the Belarusian society in terms of value priorities and found out that the demographic base of secular-individualistic and self-expression values consists of highly educated residents of large cities of younger (under 30) and middle (up to 49) age. Given the growth of the share of population with higher education and the second wave of urbanization (the outflow from small towns to large cities), we should expect an expansion of this demographic base and, accordingly, the further spread of these value orientations. In this situation, the education system acts as a source of the ongoing changes and develops the value matrix of the coming social reality

    UTILIZING SAR AND MULTISPECTRAL INTEGRATED DATA FOR EMERGENCY RESPONSE

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    Satellite images are used widely in the risk cycle to understand the exposure, refine hazard maps and quickly provide an assessment after a natural or man-made disaster. Though there are different types of satellite images (e.g. optical, radar) these have not been combined for risk assessments. The characteristics of different remote sensing data type may be extremely valuable for monitoring and evaluating the impacts of disaster events, to extract additional information thus making it available for emergency situations. To base this approach, two different change detection methods, for two different sensor's data were used: Coherence Change Detection (CCD) for SAR data and Covariance Equalization (CE) for multispectral imagery. The CCD provides an identification of the stability of an area, and shows where changes have occurred. CCD shows subtle changes with an accuracy of several millimetres to centimetres. The CE method overcomes the atmospheric effects differences between two multispectral images, taken at different times. Therefore, areas that had undergone a major change can be detected. To achieve our goals, we focused on the urban areas affected by the tsunami event in Sendai, Japan that occurred on March 11, 2011 which affected the surrounding area, coastline and inland. High resolution TerraSAR-X (TSX) and Landsat 7 images, covering the research area, were acquired for the period before and after the event. All pre-processed and processed according to each sensor. Both results, of the optical and SAR algorithms, were combined by resampling the spatial resolution of the Multispectral data to the SAR resolution. This was applied by spatial linear interpolation. A score representing the damage level in both products was assigned. The results of both algorithms, high level of damage is shown in the areas closer to the sea and shoreline. Our approach, combining SAR and multispectral images, leads to more reliable information and provides a complete scene for the emergency response following an event
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