1,131 research outputs found
Concluding remarks, trends, and future research on new working spaces
This book provided a novel understanding of the socioeconomic and spatial
consequences of the COVID-19 pandemic on NeWSps such as (i) coworking
spaces and smart work centres; (ii) makerspaces and other technical spaces (fab
labs, open workshops); (iii) other new working spaces (hackerspaces, living
labs, and corporate labs); and (iv) cofee shops and public libraries that provide
formal and informal spaces for working
Information security management:ANP based approach for risk analysis and decision making
In information systems security, the objectives of risk analysis process are to help to identify new threats and vulnerabilities, to estimate their business impact and to provide a dynamic set of tools to control the security level of the information system. The identification of risk factors as well as the estimation of their business impact require tools for assessment of risk with multi-value scales according to different stakeholders' point of view. Therefore, the purpose of this paper is to model risk analysis decision making problem using semantic network to develop the decision network and the Analytical Network Process (ANP) that allows solving complex problems taking into consideration quantitative and qualitative data. As a decision support technique ANP also measures the dependency among risk factors related to the elicitation of individual judgement. An empirical study involving the Forestry Company is used to illustrate the relevance of ANP
Torsional Directed Walks, Entropic Elasticity, and DNA Twist Stiffness
DNA and other biopolymers differ from classical polymers due to their
torsional stiffness. This property changes the statistical character of their
conformations under tension from a classical random walk to a problem we call
the `torsional directed walk'. Motivated by a recent experiment on single
lambda-DNA molecules [Strick et al., Science 271 (1996) 1835], we formulate the
torsional directed walk problem and solve it analytically in the appropriate
force regime. Our technique affords a direct physical determination of the
microscopic twist stiffness C and twist-stretch coupling D relevant for DNA
functionality. The theory quantitatively fits existing experimental data for
relative extension as a function of overtwist over a wide range of applied
force; fitting to the experimental data yields the numerical values C=120nm and
D=50nm. Future experiments will refine these values. We also predict that the
phenomenon of reduction of effective twist stiffness by bend fluctuations
should be testable in future single-molecule experiments, and we give its
analytic form.Comment: Plain TeX, harvmac, epsf; postscript available at
http://dept.physics.upenn.edu/~nelson/index.shtm
Managerial governance and transparency in public sector to improve services for citizens and companies
Recent debate and associated initiatives dealing with public sector innovation have mainly aimed at improving the effectiveness and efficiency of the delivery of public services and improved transparency and user friendliness. Beyond typical administrative reforms, innovation is expected to help address societal challenges such as the aging population, inclusion, health care, education, public safety, environment and greenhouse gas emissions reduction. The public sector consists of a complex open system of organizations with various tasks. Therefore, decision-making can be slower than in the private sector because of large chains of command. Innovations here will often have an impact across this complex organizational structure, and thus must be supported by a robust strategy. To strengthen democracy, promote government efficiency and effectiveness, discourage wastes and misuses of government resources, public administrations have to promote a new stronger level of openness in government. The purpose of this manuscript is to describe an innovative approach for the governance of public systems and services, currently applied in the Italian public administration domain, which could be easily replicated in other countries as well. Two initiatives, to collect and provide relevant public information gathered from different and heterogeneous public organizations, to improve government processes and increase quality of services for citizens and companies, are described. The cases adopted have been validated through a case analysis approach involving the Italian Agency for the public administration digitalization to understand new e-government scenarios within the context of governmental reforms heavily influenced by the principles of Open Government Model
Modeling the Emergence of Whisker Direction Maps in Rat Barrel Cortex
Based on measuring responses to rat whiskers as they are mechanically stimulated, one recent study suggests that barrel-related areas in layer 2/3 rat primary somatosensory cortex (S1) contain a pinwheel map of whisker motion directions. Because this map is reminiscent of topographic organization for visual direction in primary visual cortex (V1) of higher mammals, we asked whether the S1 pinwheels could be explained by an input-driven developmental process as is often suggested for V1. We developed a computational model to capture how whisker stimuli are conveyed to supragranular S1, and simulate lateral cortical interactions using an established self-organizing algorithm. Inputs to the model each represent the deflection of a subset of 25 whiskers as they are contacted by a moving stimulus object. The subset of deflected whiskers corresponds with the shape of the stimulus, and the deflection direction corresponds with the movement direction of the stimulus. If these two features of the inputs are correlated during the training of the model, a somatotopically aligned map of direction emerges for each whisker in S1. Predictions of the model that are immediately testable include (1) that somatotopic pinwheel maps of whisker direction exist in adult layer 2/3 barrel cortex for every large whisker on the rat's face, even peripheral whiskers; and (2) in the adult, neurons with similar directional tuning are interconnected by a network of horizontal connections, spanning distances of many whisker representations. We also propose specific experiments for testing the predictions of the model by manipulating patterns of whisker inputs experienced during early development. The results suggest that similar intracortical mechanisms guide the development of primate V1 and rat S1
Cortical Maps
In this article, we review functional organization in sensory cortical regions-how the cortex represents the world. We consider four interrelated aspects of cortical organization: (1) the set of receptive fields of individual cortical sensory neurons, (2) how lateral interaction between cortical neurons reflects the similarity of their receptive fields, (3) the spatial distribution of receptive-field properties across the horizontal extent of the cortical tissue, and (4) how the spatial distributions of different receptive-field properties interact with one another. We show how these data are generally well explained by the theory of input-driven self-organization, with a family of computational models of cortical maps offering a parsimonious account for a wide range of map-related phenomena. We then discuss important challenges to this explanation, with respect to the maps present at birth, maps present under activity blockade, the limits of adult plasticity, and the lack of some maps in rodents. Because there is not at present another credible general theory for cortical map development, we conclude by proposing key experiments to help uncover other mechanisms that might also be operating during map development
Constraints, Histones, and the 30 Nanometer Spiral
We investigate the mechanical stability of a segment of DNA wrapped around a
histone in the nucleosome configuration. The assumption underlying this
investigation is that the proper model for this packaging arrangement is that
of an elastic rod that is free to twist and that writhes subject to mechanical
constraints. We find that the number of constraints required to stabilize the
nuclesome configuration is determined by the length of the segment, the number
of times the DNA wraps around the histone spool, and the specific constraints
utilized. While it can be shown that four constraints suffice, in principle, to
insure stability of the nucleosome, a proper choice must be made to guarantee
the effectiveness of this minimal number. The optimal choice of constraints
appears to bear a relation to the existence of a spiral ridge on the surface of
the histone octamer. The particular configuration that we investigate is
related to the 30 nanometer spiral, a higher-order organization of DNA in
chromatin.Comment: ReVTeX, 15 pages, 18 figure
Fluctuating Filaments I: Statistical Mechanics of Helices
We examine the effects of thermal fluctuations on thin elastic filaments with
non-circular cross-section and arbitrary spontaneous curvature and torsion.
Analytical expressions for orientational correlation functions and for the
persistence length of helices are derived, and it is found that this length
varies non-monotonically with the strength of thermal fluctuations. In the weak
fluctuation regime, the local helical structure is preserved and the
statistical properties are dominated by long wavelength bending and torsion
modes. As the amplitude of fluctuations is increased, the helix ``melts'' and
all memory of intrinsic helical structure is lost. Spontaneous twist of the
cross--section leads to resonant dependence of the persistence length on the
twist rate.Comment: 5 figure
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