843 research outputs found
Power spectral measurements of clear-air turbulence to long wavelengths for altitudes up to 14,000 meters
Measurements of three components of clear air atmospheric turbulence were made with an airplane incorporating a special instrumentation system to provide accurate data resolution to wavelengths of approximately 12,500 m (40,000 ft). Flight samplings covered an altitude range from approximately 500 to 14,000 m (1500 to 46,000 ft) in various meteorological conditions. Individual autocorrelation functions and power spectra for the three turbulence components from 43 data runs taken primarily from mountain wave and jet stream encounters are presented. The flight location (Eastern or Western United States), date, time, run length, intensity level (standard deviation), and values of statistical degrees of freedom for each run are provided in tabular form. The data presented should provide adequate information for detailed meteorological correlations. Some time histories which contain predominant low frequency wave motion are also presented
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Push and Pull Factors: Influence on Female Managers and Executivesâ Exit From the Workplace, Impact on Job Satisfaction and Organizational Commitment
The entry of women into the professional world has, without a doubt, changed the dynamics of the workplace over the past few decades. That observation still holds true today and becomes more prevalent with the changing face of the labor market in terms of diversity. However, in spite of that strong overall female presence, there still exists an unfair share between the number of women compared to the number of men holding high managerial and executive positions. Women experience difficulties advancing in their careers because of various factors that Hewlett and Luce (2005) divided in two separate categories called âpushâ and âpullâ.
This research determined how those factors negatively influence those women\u27s job satisfaction as well as organizational commitment, and therefore increase their propensity to leave the workforce, even after they have achieved somewhat high levels in their career. The research also attempted to provide recommendation approaches to assist organizations in implementing effective retention initiatives
Early Size Distributions of Chondrule Subgroups Overprinted by the Final Accumulation Process of Particle Components in Allende
Populations of compositionally distinct particles are fundamental components of undifferentiated chondritic meteorites. Many theories explain the formation of chondrites, one class of which includes mechanisms for sorting the component particles in the solar nebula prior to their accretion. Mechanisms include sorting by mass, turbulent concentration, X-winds, and photophoresis, which will produce characteristic distributions of observable properties such as particle size. Distinguishing processes that occur in specific astrophysical environments requires characterization of particle types, which include refractory Ca-Al-rich Inclusions (CAIs) and less-refractory chondrules. Previous investigations of modal abundances of CAIs and chondrules exist, but differences within and between these two groups, both of which are made up of diverse subgroups with different thermal histories and chemical compositions, remain mostly unstudied. The presence of rims, a significant event occurring after the formation of at least some chondrules, have also yet to be considered with respect to sorting. Here we present the sizes of CAIs and chondrules in Allende with attention to the smallest sizes, subgroups, and particle rims
The HI and Ionized Gas Disk of the Seyfert Galaxy NGC 1144 = Arp 118: A Violently Interacting Galaxy with Peculiar Kinematics
We present observations of the distribution and kinematics of neutral and
ionized gas in NGC 1144, a galaxy that forms part of the Arp 118 system.
Ionized gas is present over a huge spread in velocity (1100 km/s) in the disk
of NGC 1144, but HI emission is detected over only 1/3 of this velocity range,
in an area that corresponds to the NW half of the disk. In the nuclear region
of NGC 1144, a jump in velocity in the ionized gas component of 600 km/s is
observed. Faint, narrow HI absorption lines are also detected against radio
sources in the SE part of the disk of NGC 1144, which includes regions of
massive star formation and a Seyfert nucleus. The peculiar HI distribution,
which is concentrated in the NW disk, seems to be the inverse of the molecular
distribution which is concentrated in the SE disk. Although this may partly be
the result of the destruction of HI clouds in the SE disk, there is
circumstantial evidence that the entire HI emission spectrum of NGC 1144 is
affected by a deep nuclear absorption line covering a range of 600 km/s, and is
likely blueshifted with respect to the nucleus. In this picture, a high
column-density HI stream is associated with the nuclear ionized gas velocity
discontinuity, and the absorption effectively masks any HI emission that would
be present in the SE disk of NGC 1144.Comment: manuscript, arp118.ps: 28 pages; 1 Table: arp118.tab1.ps; 16 Figures:
arp118.fig1-16.ps; Accepted to Ap
Elevational richness patterns of sphingid moths support area effects over climatic drivers in a nearâglobal analysis
Not sure if this is the pre-refereed or final submitted version.Aim
We test hypotheses on the environmental control of elevational richness patterns of sphingid moths for their global applicability and generality. Specifically, we compare effects of area with climateârelated drivers, such as primary productivity and temperature, while also considering direct effects of precipitation.
Major taxa
Sphingid moths (Lepidoptera).
Location
Eightyâsix mountain ranges of the Old World and the Australia/Pacific region, from Scandinavia and Siberia through the African and Australasian tropics to South Africa and Southern Australia.
Methods
We used a large compilation of point locality records for 744 species, in addition to fineâgrained range maps derived from species distribution modelling of these records, to characterize the elevational pattern of species richness in 86 customâdelineated mountain regions. For both types of data, we compared the effects of environmental drivers on richness by comparing standardized coefficients of multivariate models for pooled data after accounting for betweenâregion variation in richness.
Results
We observed varying patterns of elevational richness across the research region, with a higher prevalence of midpeaks in arid regions. We found overwhelming support for area as a main determinant of richness, modulated by temperature and productivity, whereas we detected no effect of precipitation.
Main conclusions
Area, productivity and temperature are the main environmental predictors explaining a large proportion of variability in sphingid richness. This is consistent not only with other elevational studies, but also with empirical and theoretical biodiversity research in a nonâelevational context (with the caveat of some unresolved issues in elevational area effects). However, distinct differences in elevational patterns remain even within the same mountain ranges when comparing with other Lepidoptera, that is, geometrid moths, which highlights the importance of understanding higher clade differentiation in ecological responses, within insects and in other groups.© 2019 John Wiley & Sons Ltd. This is the pre-peer reviewed version of the following article: BĂ€rtschi, F, McCain, CM, BallesterosâMejia, L, Kitching, IJ, Beerli, N, Beck, J. Elevational richness patterns of sphingid moths support area effects over climatic drivers in a nearâglobal analysis. Global Ecol Biogeogr. 2019; 28: 917â 927. https://doi.org/10.1111/geb.12903, which has been published in final form at doi:10.1111/geb.12903. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
Whither Evidentialist Reliabilism?
Evidentialism and Reliabilism are two of the main contemporary theories of epistemic justification. Some authors have thought that the theories are not incompatible with each other, and that a hybrid theory which incorporates elements of both should be taken into account. More recently, other authors have argued that the resulting theory is well- placed to deal with fine-grained doxastic attitudes (credences).
In this paper I review the reasons for adopting this kind of hybrid theory, paying attention to the case of credences and the notion of probability involved in their treatment. I argue that the notion of probability in question can only be an epistemic (or evidential) kind of probability. I conclude that the resulting theory will be incompatible with Reliabilism in one important respect: it cannot deliver on the reductivist promise of Reliabilism. I also argue that attention to the justification of basic beliefs reveals limitations in the Evidentialist framework as well. The theory that results from the right combination of Evidentialism and Reliabilism, therefore, is neither Evidentialist nor Reliabilist
Particle size distributions in chondritic meteorites: Evidence for pre-planetesimal histories
Magnesium-rich silicate chondrules and calcium-, aluminum-rich refractory inclusions (CAIs) are fundamental components of primitive chondritic meteorites. It has been suggested that concentration of these early-formed particles by nebular sorting processes may lead to accretion of planetesimals, the planetary bodies that represent the building blocks of the terrestrial planets. In this case, the size distributions of the particles may constrain the accretion process. Here we present new particle size distribution data for Northwest Africa 5717, a primitive ordinary chondrite (ungrouped 3.05) and the well-known carbonaceous chondrite Allende (CV3). Instead of the relatively narrow size distributions obtained in previous studies (Ebel et al., 2016, Friedrich et al., 2015, Paque and Cuzzi, 1997, and references therein), we observed broad size distributions for all particle types in both meteorites. Detailed microscopic image analysis of Allende shows differences in the size distributions of chondrule subtypes, but collectively these subpopulations comprise a composite âchondruleâ size distribution that is similar to the broad size distribution found for CAIs. Also, we find accretionary âdustâ rims on only a subset (âŒ15â20%) of the chondrules contained in Allende, which indicates that subpopulations of chondrules experienced distinct histories prior to planetary accretion. For the rimmed subset, we find positive correlation between rim thickness and chondrule size. The remarkable similarity between the size distributions of various subgroups of particles, both with and without fine grained rims, implies a common size sorting process. Chondrite classification schemes, astrophysical disk models that predict a narrow chondrule size population and/or a common localized formation event, and conventional particle analysis methods must all be critically reevaluated. We support the idea that distinct âlithologiesâ in NWA 5717 are nebular aggregates of chondrules. If â„cm-sized aggregates of chondrules can form it will have implications for planet formation and suggests the sticking stage is where the preferential size physics is operating
Theoretical studies of the historical development of the accounting discipline: a review and evidence
Many existing studies of the development of accounting thought have either been atheoretical or have adopted Kuhn's model of scientific growth. The limitations of this 35-year-old model are discussed. Four different general neo-Kuhnian models of scholarly knowledge development are reviewed and compared with reference to an analytical matrix. The models are found to be mutually consistent, with each focusing on a different aspect of development. A composite model is proposed. Based on a hand-crafted database, author co-citation analysis is used to map empirically the entire literature structure of the accounting discipline during two consecutive time periods, 1972â81 and 1982â90. The changing structure of the accounting literature is interpreted using the proposed composite model of scholarly knowledge development
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