2,301 research outputs found
Brain mechanisms of arousal, attention and perception
Neural mechanisms underlying visual perception, arousal, and attention processes in man, cat, and monke
Organizational learning and emotion: constructing collective meaning in support of strategic themes
Missing in the organizational learning literature is an integrative framework that reflects the emotional as well as the cognitive dynamics involved. Here, we take a step in this direction by focusing in depth over time (five years) on a selected organization which manufactures electronic equipment for the office industry. Drawing on personal construct theory, we define organizational learning as the collective re-construal of meaning in the direction of strategically significant themes. We suggest that emotions arise as members reflect on progress or lack of progress in achieving organizational learning. Our evidence suggests that invalidation – where organizational learning fails to correspond with expectations – gives rise to anxiety and frustration, while validation – where organizational learning is aligned with or exceeds expectations – evokes comfort or excitement. Our work aims to capture the key emotions involved as organizational learning proceeds
Isolation of H5N6, H7N9 and H9N2 avian influenza A viruses from air sampled at live poultry markets in China, 2014 and 2015
Zoonotic infections by avian influenza viruses occur at the human-poultry interface, but the modes of transmission have not been fully investigated. We assessed the potential for airborne and fomite transmission at live poultry markets in Guangzhou city and in Hong Kong Special Administrative Region (SAR), China, during 2014 and 2015. Viral genome and infectious avian influenza A viruses of H5N6, H7N9, and H9N2 subtypes were detected predominantly from particles larger or equal to 1 μm in diameter in the air sampled with cyclone-based bioaerosol samplers at the live poultry markets in Guangzhou. Influenza A(H9N2) viruses were ubiquitously isolated every month during the study period from air and environmental swabs, and different lineages of H9N2 virus were isolated from markets where chickens and minor land-based poultry were sold. The use of de-feathering devices increased the quantity of virus-laden airborne particles while market closure reduced the amount of such particles. The results highlight the possibility of airborne transmission of avian influenza viruses among poultry or from poultry to humans within such settings. This may explain epidemiological observations in which some patients with H7N9 infection reported being in markets but no direct contact with live poultry or poultry stalls.published_or_final_versio
Fitting Tidal Constituents to Altimeter Data
The gravitational influence of the Moon and Sun have a well-known influence on the Earth’s ocean levels: tides. Radar altimeters make precise measurements of the height of the instrument above ground. With a known altimeter orbit and measured altitude, the height of the ocean tide can be measured to centimetric scales. Accounting for the tidal forces from celestial objects is an important step in finding the residual sea level height. In this paper radar altimeter data from Jason-2 is used to estimate the magnitude and phase of eight dominant tidal constituents over six study regions. Each constituent is estimated by fitting the data to a Fourier series to estimate tidal magnitue and phase. Accounting for the tidal components selected for this paper largely models the tides, but some residual variance remains. This is attributed to an incomplete tidal model and to measurement and model error
ELECTRON MICROSCOPY OF PLASMA-CELL TUMORS OF THE MOUSE : I. MPC-1 and X5563 Tumors
An electron microscope study was made of a series of transplanted MPC-1 plasma-cell tumors carried by BALB/c mice. Large numbers of particles similar in morphology to virus particles were present inside the endoplasmic reticulum of tumor plasma cells. Very few particles were seen outside the cells or in ultracentrifuged preparations of the plasma or ascites fluid. In very early tumors particles were occasionally seen free in the cytoplasm adjacent to finely granular material. In general, the distribution of these particles inside endoplasmic reticulum is similar in early and late tumors. A few transplanted X5563 tumors of C3H mice were also examined. Large numbers of particles were found in the region of the Golgi apparatus in late X5663 tumors. A newly described cytoplasmic structure of plasma cells, here called a "granular body," appears to be associated with the formation of the particles. Particles present in MPC-1 tumors are exclusively of a doughnut form, whereas some of those in the inclusions of the late X5563 tumors show a dense center. Normal plasma cells, produced by inoculation of a modified Freund adjuvant into BALB/c mice. have been compared morphologically with tumor plasma cells of both tumor lines
Diagnosis of progressive disseminated histoplasmosis in advanced HIV: A meta-analysis of assay analytical performance
Histoplasmosis is an important cause of mortality in people with advanced HIV, especially in countries with limited access to diagnostic assays. Histoplasmosis can be diagnosed using culture, histopathology, and antibody, antigen, and molecular assays. Several factors may affect the analytical performance of these laboratory assays, including sample type, clinical stage of the disease, and previous use of antifungal treatment, among others. Here we describe the results of a systematic literature review, followed by ameta-analysis of the analytical performances of the diagnostic laboratory assays employed. Our initial search identified 1631 references, of which 1559 references were excluded after title and abstract screening, leaving 72 references identified as studies relevant to the validation of histoplasmosis diagnostic assays. After evaluating the full text, 30 studies were selected for final review, including one paper not identified in the initial search. The meta-analysis for assay analytical performance shows the following results for the overall sensitivity (Sen) and specificity (Spe) of the various methods evaluated: Culture, Sen 77%(no data for specificity calculation); antibody detection assays, Sen 58%/Spe 100%; antigen detection assays, Sen 95%/Spe 97%; and DNA detection assays (molecular), Sen 95%/Spe 99%. Of the 30 studies reviewed, nearly half (n = 13) evaluated Histoplasma antigen assays, which were determined to be the most accurate methodology for diagnosis of progressive disseminated histoplasmosis in advanced HIV (inverse of the negative likelihood ratio was 13.2). Molecular assays appear promising for accurate diagnosis of histoplasmosis, but consensus on exact techniques is needed. Cultures showed variable sensitivity related to sample type and laboratory handling. Finally, antibody assays presented high specificity but low sensitivity. This poor sensitivity is most likely due the highly immunosuppressed state of this patient population. Diagnostic assays are crucial for accurate diagnosis of progressive disseminated histoplasmosis (PDH) with advanced HIV disease. © 2019 by the authors. All rights reserved
Mission impossible? The paradoxes of stretch goal setting
© 2016, © The Author(s) 2016. Stretch goal setting is a process involving multiple and nested paradoxes. The paradoxical side of stretch is attractive because it holds great promise yet dangerous because it triggers processes that are hard to control. Paradoxes are not readily managed by assuming a linear relation between the here and now and the intended future perfect. Before adopting stretch goal setting, managers should thus be prepared for the tensions and contradictions created by nested or interwoven paradoxes. Achieving stretch goals can be as difficult for the managers seeking to direct the process as for designated delegates. While the increasing popularity of stretch goal setting is understandable, its unexpected consequences must be taken into account. The inadequate use of stretch goals can jeopardize the social sustainability of organizations as well as their societal support systems
New Alloying Systems for Sintered Steels: Critical Aspects of Sintering Behavior
Oxygen-sensitive alloying elements such as Mn, Si, and Cr have a high potential for improving the properties of low alloyed sintered steels while reducing the alloying cost. However, it is necessary to find a way for avoiding, or at least minimizing, the oxidation of these elements especially during the early stages of the sintering cycle. In this study Mn, Si, and Cr were introduced in the form of a master alloy powder designed to be mixed with the iron base powder and provide the final composition of the steel during the sintering process. The reduction/oxidation phenomena taking place during the heating stage were studied by thermogravimetry, dilatometry, and mass spectroscopy, using either reducing (H2) or inert (Ar) atmospheres. The results show how the difference in chemical activity between base iron powder and master alloy causes the so called "internal-getter" effect, by which the reduction of less stable iron oxides leads to oxidation of the elements with higher affinity for oxygen. This effect can be somehow minimized when sintering in H2, since the iron oxides are reduced at lower temperatures at which the reactivity of the elements in the master alloy is lower. However, H2 concentration in the processing atmosphere needs to be carefully adapted to the specific composition of the materials being processed in order to minimize decarburization by methane formation during sintering.Höganäs AB Sweden, financial support provided through the Höganäs Chair IVPublicad
Early lineage restriction in temporally distinct populations of Mesp1 progenitors during mammalian heart development.
Cardiac development arises from two sources of mesoderm progenitors, the first heart field (FHF) and the second (SHF). Mesp1 has been proposed to mark the most primitive multipotent cardiac progenitors common for both heart fields. Here, using clonal analysis of the earliest prospective cardiovascular progenitors in a temporally controlled manner during early gastrulation, we found that Mesp1 progenitors consist of two temporally distinct pools of progenitors restricted to either the FHF or the SHF. FHF progenitors were unipotent, whereas SHF progenitors were either unipotent or bipotent. Microarray and single-cell PCR with reverse transcription analysis of Mesp1 progenitors revealed the existence of molecularly distinct populations of Mesp1 progenitors, consistent with their lineage and regional contribution. Together, these results provide evidence that heart development arises from distinct populations of unipotent and bipotent cardiac progenitors that independently express Mesp1 at different time points during their specification, revealing that the regional segregation and lineage restriction of cardiac progenitors occur very early during gastrulation.This is the author's accepted manuscript and will be under embargo until the 24th of February 2015. The final version is published by NPG in Nature Cell Biology here: http://www.nature.com/ncb/journal/v16/n9/full/ncb3024.html
- …
