62 research outputs found
Middle East Health and Air Quality Utilizing NASA EOS in the Saharan and Arabian Deserts to Examine Dust Particle Size and Mineralogy of Aerosols
Ground-based studies conducted in Iraq have revealed the presence of potential human pathogens in airborne dust. According to the Environmental Protection Agency (EPA), airborne particulate matter below 2.5micron (PM2.5) can cause long-term damage to the human respiratory system. NASA fs Earth Observing System (EOS) can be used to determine spectral characteristics of dust particles and dust particle sizes. Comparing dust particle size from the Sahara and Arabian Deserts gives insight into the composition and atmospheric transport characteristics of dust from each desert. With the use of NASA SeaWiFS DeepBlue Aerosol, dust particle sizes were estimated using Angstrom Exponent. Brightness Temperature Difference (BTD) equation was used to determine the area of the dust storm. The Moderate-resolution Imaging Spectroradiometer (MODIS) on Terra satellite was utilized in calculating BTD. Mineral composition of a dust storm that occurred 17 April 2008 near Baghdad was determined using imaging spectrometer data from the JPL Spectral Library and EO-1 Hyperion data. Mineralogy of this dust storm was subsequently compared to that of a dust storm that occurred over the Bodele Depression in the Sahara Desert on 7 June 2003
The Maunakea Spectroscopic Explorer Book 2018
(Abridged) This is the Maunakea Spectroscopic Explorer 2018 book. It is
intended as a concise reference guide to all aspects of the scientific and
technical design of MSE, for the international astronomy and engineering
communities, and related agencies. The current version is a status report of
MSE's science goals and their practical implementation, following the System
Conceptual Design Review, held in January 2018. MSE is a planned 10-m class,
wide-field, optical and near-infrared facility, designed to enable
transformative science, while filling a critical missing gap in the emerging
international network of large-scale astronomical facilities. MSE is completely
dedicated to multi-object spectroscopy of samples of between thousands and
millions of astrophysical objects. It will lead the world in this arena, due to
its unique design capabilities: it will boast a large (11.25 m) aperture and
wide (1.52 sq. degree) field of view; it will have the capabilities to observe
at a wide range of spectral resolutions, from R2500 to R40,000, with massive
multiplexing (4332 spectra per exposure, with all spectral resolutions
available at all times), and an on-target observing efficiency of more than
80%. MSE will unveil the composition and dynamics of the faint Universe and is
designed to excel at precision studies of faint astrophysical phenomena. It
will also provide critical follow-up for multi-wavelength imaging surveys, such
as those of the Large Synoptic Survey Telescope, Gaia, Euclid, the Wide Field
Infrared Survey Telescope, the Square Kilometre Array, and the Next Generation
Very Large Array.Comment: 5 chapters, 160 pages, 107 figure
The longitudinal association between anxiety and Internet addiction in adolescence: the moderating effect of classroom extraversion
Background and aims: The risk effect of anxiety on addictive behaviors, including Internet addiction (IA), has repeatedly been highlighted in the international literature. However, there is a lack of longitudinal studies examining this association in relation to proximal context effects, particularly in adolescence. Such findings would shed light on potential age- and proximal context-related variations in the anxiety–IA association that could better inform IA prevention and intervention initiatives. Methods: In this study, 648 adolescents, embedded in 34 classrooms, were assessed at the age of 16 and again at the age of 18 to examine the effect of anxiety on IA behaviors in relation to the
average level of classroom extraversion. IA was assessed with the Internet Addiction Test (Young, 1998), anxiety with the relevant subscale of the Symptom Checklist 90 – Revised (Derogatis & Savitz, 1999) and classroom extraversion with the synonymous subscale of the Five Factor Questionnaire (Asendorpf & van Aken, 2003). A three-level hierarchical linear model was calculated. Results: The present findings demonstrated that: (a) higher levels of anxiety were significantly associated with higher IA behaviors, (b) the strength of this association did not vary over time (between 16 and 18 years old), and (c) however, it tended to weaken within classrooms higher in extraversion. Discussion: This
study indicated that the contribution of individual IA risk factors might differently unfold within different contexts
Feedback as intervention for team learning in virtual teams: the role of team cohesion and personality
Scholars and practitioners agree that virtual teams (VTs) have become commonplace in today's digital workplace. Relevant literature argues that learning constitutes a significant contributor to team member satisfaction and performance, and that, at least in face-to-face teams, team cohesion fosters team learning. Given the additional challenges VTs face, e.g. geographical dispersion, which are likely have a negative influence on cohesion, in this paper we shed light on the relationship between team cohesion and team learning. We adopted a quantitative approach and studied 54 VTs in our quest to understand the role of feedback in mediating this relationship and, more specifically, the role of personality traits in moderating the indirect effect of team feedback and guided reflection intervention on TL through team cohesion within the VT context. Our findings highlight the importance of considering aspects related to the team composition when devising intervention strategies for VTs, and provide empirical support for an interactionist model between personality and emergent states such as cohesion. Implications for theory and practice are also discussed
The Energy Landscapes of Repeat-Containing Proteins: Topology, Cooperativity, and the Folding Funnels of One-Dimensional Architectures
Repeat-proteins are made up of near repetitions of 20– to 40–amino acid stretches. These polypeptides usually fold up into non-globular, elongated architectures that are stabilized by the interactions within each repeat and those between adjacent repeats, but that lack contacts between residues distant in sequence. The inherent symmetries both in primary sequence and three-dimensional structure are reflected in a folding landscape that may be analyzed as a quasi–one-dimensional problem. We present a general description of repeat-protein energy landscapes based on a formal Ising-like treatment of the elementary interaction energetics in and between foldons, whose collective ensemble are treated as spin variables. The overall folding properties of a complete “domain” (the stability and cooperativity of the repeating array) can be derived from this microscopic description. The one-dimensional nature of the model implies there are simple relations for the experimental observables: folding free-energy (ΔGwater) and the cooperativity of denaturation (m-value), which do not ordinarily apply for globular proteins. We show how the parameters for the “coarse-grained” description in terms of foldon spin variables can be extracted from more detailed folding simulations on perfectly funneled landscapes. To illustrate the ideas, we present a case-study of a family of tetratricopeptide (TPR) repeat proteins and quantitatively relate the results to the experimentally observed folding transitions. Based on the dramatic effect that single point mutations exert on the experimentally observed folding behavior, we speculate that natural repeat proteins are “poised” at particular ratios of inter- and intra-element interaction energetics that allow them to readily undergo structural transitions in physiologically relevant conditions, which may be intrinsically related to their biological functions
Discrete Kinetic Models from Funneled Energy Landscape Simulations
A general method for facilitating the interpretation of computer simulations of protein folding with minimally frustrated energy landscapes is detailed and applied to a designed ankyrin repeat protein (4ANK). In the method, groups of residues are assigned to foldons and these foldons are used to map the conformational space of the protein onto a set of discrete macrobasins. The free energies of the individual macrobasins are then calculated, informing practical kinetic analysis. Two simple assumptions about the universality of the rate for downhill transitions between macrobasins and the natural local connectivity between macrobasins lead to a scheme for predicting overall folding and unfolding rates, generating chevron plots under varying thermodynamic conditions, and inferring dominant kinetic folding pathways. To illustrate the approach, free energies of macrobasins were calculated from biased simulations of a non-additive structure-based model using two structurally motivated foldon definitions at the full and half ankyrin repeat resolutions. The calculated chevrons have features consistent with those measured in stopped flow chemical denaturation experiments. The dominant inferred folding pathway has an “inside-out”, nucleation-propagation like character
Invited reaction: Investigating the influences of core self-evaluations, job autonomy, and intrinsic motivation on in-role job performance
Business; Human Resources Managemen
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