1,904 research outputs found

    How the Individual Differences of Subordinates Within the Workplace Predict Leadership Style Preference and Organizational Commitment

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    The connection between leader and subordinate is a crucial one for businesses. One reason this connection is crucial is that many subordinates see the business through the eyes of their managers or super-ordinates. Leaders with certain abilities and attributes can help employees feel more comfortable with their work environment. Different subordinates in specific work environment situations may desire different attributes in a leader. Conversely, individuals with specific personality attributes and a similar work environment may, therefore, desire the same type of leader. The following study will attempt to describe the relations between subordinates\u27 personality characteristics, gender, job stereo typicality and emotional intelligence, their preferred type of leader and, finally their commitment to their organization

    New insights into pedestrian flow through bottlenecks

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    Capacity estimation is an important tool for the design and dimensioning of pedestrian facilities. The literature contains different procedures and specifications which show considerable differences with respect to the estimated flow values. Moreover do new experimental data indicate a stepwise growing of the capacity with the width and thus challenge the validity of the specific flow concept. To resolve these differences we have studied experimentally the unidirectional pedestrian flow through bottlenecks under laboratory conditions. The time development of quantities like individual velocities, density and individual time gaps in bottlenecks of different width is presented. The data show a linear growth of the flow with the width. The comparison of the results with experimental data of other authors indicates that the basic assumption of the capacity estimation for bottlenecks has to be revised. In contradiction with most planning guidelines our main result is, that a jam occurs even if the incoming flow does not overstep the capacity defined by the maximum of the flow according to the fundamental diagram.Comment: Traffic flow, pedestrian traffic, crowd dynamics, capacity of bottlenecks (16 pages, 8 figures); (+ 3 new figures and minor revisions

    Bond Orientational Order, Molecular Motion and Free Energy of High Density DNA Mesophases

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    By equilibrating condensed DNA arrays against reservoirs of known osmotic stress and examining them with several structural probes, it has been possible to achieve a detailed thermodynamic and structural characterization of the change between two distinct regions on the liquid crystalline phase digram: a higher-density hexagonally packed region with long-range bond orientational order in the plane perpendicular to the average molecular direction; and a lower-density cholesteric region with fluid-like positional order. X-rays scattering on highly ordered DNA arrays at high density and with the helical axis oriented parallel to the incoming beam showed a six-fold azimuthal modulation of the first order diffraction peak that reflects the macroscopic bond-orientational order. Transition to the less-dense cholesteric phase through osmotically controlled swelling shows the loss of this bond orientational order that had been expected from the change in optical birefringence patterns and that is consistent with a rapid onset of molecular positional disorder. This change in motion was previously inferred from intermolecular force measurements and is now confirmed by 31P\rm ^{31}P NMR. Controlled reversible swelling and compaction under osmotic stress, spanning a range of densities between 120\sim 120 mg/ml to 600\sim 600 mg/ml, allows measurement of the free energy changes throughout each phase and at the phase transition, essential information for theories of liquid-crystalline states.Comment: 14 pages, 3 figures in gif format available at http://abulafia.mgsl.dcrt.nih.gov/pics.html E-mail: [email protected]

    The chemokine CXCL13 in acute neuroborreliosis

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    Objective Recent studies have suggested an important role of the B cell chemoattractant CXCL13 in acute neuroborreliosis (NB). Our aim was to confirm the diagnostic role of CXCL13 and to evaluate its relevance as a therapy response and disease activity marker in NB. Methods CXCL13 was measured in cerebrospinal fluid (CSF) and serum of patients with NB (n = 28), systemic borreliosis (SB, n = 9), Guillaine-Barre syndrome (GBS, n = 11), Bell's palsy (BP, n = 19), other cranial nerve palsies (CNP, n = 5), cephalgia (C, n = 20), bacterial CNS infections (B-CNS-I, n = 16) and viral CNS infections (V-CNS-I, n = 18). For follow-up studies, serial sample pairs were evaluated from 25 patients with NB (n = 56), 11 with B-CNS-I (n = 25) and 14 with V-CNS-I (n = 36). Results CSF-CXCL13 was significantly elevated in NB compared with other neurological diseases (p<0.001). Using receiver operating characteristic analysis, 337 ng/g was determined as a cut-off with a sensitivity of 96.4% and a specificity of 96.9%. Of all the parameters investigated, CSF CXCL13 showed the fastest response to antibiotic therapy, decreasing significantly (p = 0.008) within 1 week. In untreated patients, CSF CXCL13 was elevated in patients with a short duration of disease. Borrelia burgdorferi antibody index showed no significant (p = 0.356) change over follow-up. Conclusions The study confirms the relevance of CXCL13 as a diagnostic biomarker of NB and suggests that CSF CXCL13 in NB is linked to duration of disease and could be a marker of disease activity and response to antibiotic therapy

    Transmission dynamics and prospects for the elimination of canine rabies

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    Rabies has been eliminated from domestic dog populations in Western Europe and North America, but continues to kill many thousands of people throughout Africa and Asia every year. A quantitative understanding of transmission dynamics in domestic dog populations provides critical information to assess whether global elimination of canine rabies is possible. We report extensive observations of individual rabid animals in Tanzania and generate a uniquely detailed analysis of transmission biology, which explains important epidemiological features, including the level of variation in epidemic trajectories. We found that the basic reproductive number for rabies, R&lt;sub&gt;0&lt;/sub&gt;, is very low in our study area in rural Africa (&#8764;1.2) and throughout its historic global range (&#60;2). This finding provides strong support for the feasibility of controlling endemic canine rabies by vaccination, even near wildlife areas with large wild carnivore populations. However, we show that rapid turnover of domestic dog populations has been a major obstacle to successful control in developing countries, thus regular pulse vaccinations will be required to maintain population-level immunity between campaigns. Nonetheless our analyses suggest that with sustained, international commitment, global elimination of rabies from domestic dog populations, the most dangerous vector to humans, is a realistic goal

    Sharp interface limit for a phase field model in structural optimization

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    We formulate a general shape and topology optimization problem in structural optimization by using a phase field approach. This problem is considered in view of well-posedness and we derive optimality conditions. We relate the diffuse interface problem to a perimeter penalized sharp interface shape optimization problem in the sense of Γ\Gamma-convergence of the reduced objective functional. Additionally, convergence of the equations of the first variation can be shown. The limit equations can also be derived directly from the problem in the sharp interface setting. Numerical computations demonstrate that the approach can be applied for complex structural optimization problems

    PASS: An ImageNet replacement for self-supervised pretraining without humans

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    Computer vision has long relied on ImageNet and other large datasets of images sampled from the Internet for pretraining models. However, these datasets have ethical and technical shortcomings, such as containing personal information taken without consent, unclear license usage, biases, and, in some cases, even problematic image content. On the other hand, state-of-the-art pretraining is nowadays obtained with unsupervised methods, meaning that labelled datasets such as ImageNet may not be necessary, or perhaps not even optimal, for model pretraining. We thus propose an unlabelled dataset PASS: Pictures without humAns for Self-Supervision. PASS only contains images with CC-BY license and complete attribution metadata, addressing the copyright issue. Most importantly, it contains no images of people at all, and also avoids other types of images that are problematic for data protection or ethics. We show that PASS can be used for pretraining with methods such as MoCo-v2, SwAV and DINO. In the transfer learning setting, it yields similar downstream performances to ImageNet pretraining even on tasks that involve humans, such as human pose estimation. PASS does not make existing datasets obsolete, as for instance it is insufficient for benchmarking. However, it shows that model pretraining is often possible while using safer data, and it also provides the basis for a more robust evaluation of pretraining methods

    Innovation and modernization to prolong the South African mining beyond 2040

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    In June 2016, the Southern African Institute of Mining and Metallurgy (SAIMM) held a colloquium in Johannesburg South Africa the purpose of which was to create a dialogue between industry, government, research institutes and academia in the area of new technology and innovation. One of the key findings presented at the colloquium was the Chamber of Mines (COM) study indicating that the South African gold reserves dependent upon conventional mining methods will be depleted by 2031 with Platinum Group Metals (PGM) reserves signaling a similar fate..
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