14,081 research outputs found
The use of NASTRAN in the design of wind tunnel research aircraft
The relationship between NASTRAN and the wind tunnel model design process is discussed. Specific cases illustrating the use of NASTRAN for static, heat transfer, dynamic, and aeroelastic analyses are presented. Advantages and disadvantages of using NASTRAN are summarized
Galaxy Environments in DEEP2: The Birth of the Red Sequence
The DEEP2 Galaxy Redshift Survey is the first project to study the distant
Universe by obtaining a data set comparable in size and nature to recent
generations of local surveys. Made possible by the largest ground-based optical
telescopes and new instrumentation, DEEP2 was designed to measure both the
properties of galaxies at z ~ 1 and their distribution in space, enabling a
number of unique tests of galaxy formation and evolution. Here, we first
provide an overview of the survey, including the planned second major data
release scheduled for early 2007. We then present new results from DEEP2
pertaining to the relationship between galaxy properties and environment at
intermediate redshift, revealing where and when typical ~L* galaxies began
quenching and moved onto the red sequence in significant number.Comment: 2 pages (1 figure), for the IAU Symposium 235, Galaxies Across the
Hubble Time, J. Palous & F. Combes, eds. Uses iaus.cls, include
Job-related stress and burnout
Occupational stress is a topic of substantial interest to organizational researchers and managers, as well as society at large. Stress arising from work conditions can be pervasive and significant in its impact on individuals, their families and organizations. There is also a widespread belief that management of job stress is a key factor for enhancing individual performance on the job, hence increasing organizational effectiveness. Sethi and Schuler 1984 outlined four major reasons why job stress and coping have become prominent issues: a concern for individual employee health and well-being; b the financial impact on organizations including days lost due to stress-related illness; c organizational effectiveness; and d legal obligations on employers to provide safe and healthy working environments
Determinants of job satisfaction and dissatisfaction among practitioners employed in intercollegiate sport organizations
The purpose of this study was to gain insight into factors that influence job satisfaction and dissatisfaction among intercollegiate athletics department employees. Factors influencing job satisfaction could impact one’s job performance and willingness to remain in a job. When employees are satisfied with their work, they are more likely to remain at their job and successfully complete tasks in association with the job (Kaltenbaugh, 2009; Dixon & Warner, 2010). In order to gain insight with regard to factors influencing job satisfaction, five individuals who were employed within intercollegiate athletics departments participated in this study. Four of the participants worked at NCAA Division I institutions. One participant worked at an NCAA Division II institution. Two themes responsible for feelings of satisfaction and two themes connected to feelings of dissatisfaction emerged from the interview data. The themes related to satisfaction were: (a) student development and achievement and (b) workplace relationships and environment. The themes related to dissatisfaction were: (a) personnel management and (b) financial pressures /lack of resources. Further examination of perspectives and experiences of current employees could be beneficial to those who are interested in pursuing a career in this profession. Understanding the elements that contribute to job satisfaction could help upper level management attract and retain quality employees. In addition, these findings can help individuals who possess an interest in entering the sport industry be better prepared for the challenges and circumstances they might encounter
Local taxation, spending and poverty : new choices and tax justice
In the environment of the 2014 Independence Referendum, a number of key questions have been raised about the future Scotland we want to see and live in. Core to such discussions have been the interventions on wealth creation and benefits, by the leaders of the Conservatives and Labour Parties in Scotland, respectively. However, and as rigorously debated in the Whose Economy? Seminar Series (Danson and Trebeck, 2011), such questions need to be considered in their wider contexts to identify and analyse fully all aspects of ‘who pays?’ and ‘who benefits?’. Indeed, several of the papers to that seminar series echoed previous classical work on poverty and the welfare state by Townsend, Abel-Smith and others which confirmed there are some long-standing myths to be addressed. These commentaries have suggested that all is not what it seems in the review of statistics of income and benefits, and robust, objective and clinical assessment of the dat
Temperature-based metallicity measurements at z=0.8: direct calibration of strong-line diagnostics at intermediate redshift
We present the first direct calibration of strong-line metallicity
diagnostics at significant cosmological distances using a sample at z=0.8 drawn
from the DEEP2 Galaxy Redshift Survey. Oxygen and neon abundances are derived
from measurements of electron temperature and density. We directly compare
various commonly used relations between gas-phase metallicity and strong line
ratios of O, Ne, and H at z=0.8 and z=0. There is no evolution with redshift at
high precision (, ). O, Ne, and H line ratios follow the same
locus at z=0.8 as at z=0 with 0.02 dex evolution and low scatter
(0.04 dex). This suggests little or no evolution in physical
conditions of HII regions at fixed oxygen abundance, in contrast to models
which invoke more extreme properties at high redshifts. We speculate that
offsets observed in the [N II]/H versus [O III]/H diagram at
high redshift are therefore due to [NII] emission, likely as a result of
relatively high N/O abundance. If this is indeed the case, then nitrogen-based
metallicity diagnostics suffer from systematic errors at high redshift. Our
findings indicate that locally calibrated abundance diagnostics based on
alpha-capture elements can be reliably applied at z1 and possibly at
much higher redshifts. This constitutes the first firm basis for the widespread
use of empirical calibrations in high redshift metallicity studies.Comment: 14 pages, 10 figures, accepted to Ap
Real Estate Securities and a Filter-based, Short-term Trading Strategy
Anecdotal evidence provides overwhelming support to the belief that sophisticated real estate investors profit by timing long-run real estate cycles. This article examines the investment performance benefits that sophisticated investors may derive from short-run cycles in real estate, specifically, through the publicly traded real estate markets. Using a simple strategy that filters out noise in real estate investment trust (REIT) price reversals, this study shows that a contrarian strategy is many times more profitable than the associated execution costs. Furthermore, the study demonstrates that the REIT market has been sufficiently liquid to execute this trading strategy. This last point is directly related to the filter strategy since only REITs with large price movements satisfy the hypothetical investor’s selection criteria.
The Local Group: The Ultimate Deep Field
Near-field cosmology -- using detailed observations of the Local Group and
its environs to study wide-ranging questions in galaxy formation and dark
matter physics -- has become a mature and rich field over the past decade.
There are lingering concerns, however, that the relatively small size of the
present-day Local Group ( Mpc diameter) imposes insurmountable
sample-variance uncertainties, limiting its broader utility. We consider the
region spanned by the Local Group's progenitors at earlier times and show that
it reaches co-moving Mpc in linear size (a volume of ) at . This size at early cosmic epochs is large enough
to be representative in terms of the matter density and counts of dark matter
halos with . The Local
Group's stellar fossil record traces the cosmic evolution of galaxies with
(reaching
at ) over a region that is comparable to or larger than
the Hubble Ultra-Deep Field (HUDF) for the entire history of the Universe. It
is highly complementary to the HUDF, as it probes much fainter galaxies but
does not contain the intrinsically rarer, brighter sources that are detectable
in the HUDF. Archaeological studies in the Local Group also provide the ability
to trace the evolution of individual galaxies across time as opposed to
evaluating statistical connections between temporally distinct populations. In
the JWST era, resolved stellar populations will probe regions larger than the
HUDF and any deep JWST fields, further enhancing the value of near-field
cosmology.Comment: 6 pages, 5 figures; MNRAS Letters, in pres
Optogenetic control of genetically-targeted pyramidal neuron activity in prefrontal cortex
A salient feature of prefrontal cortex organization is the vast diversity of cell types that support the temporal integration of events required for sculpting future responses. A major obstacle in understanding the routing of information among prefrontal neuronal subtypes is the inability to manipulate the electrical activity of genetically defined cell types over behaviorally relevant timescales and activity patterns. To address these constraints, we present here a simple approach for selective activation of prefrontal excitatory neurons in both in vitro and in vivo preparations. Rat prelimbic pyramidal neurons were genetically targeted to express a light-­activated nonselective cation channel, channelrhodopsin-­2, or a light-­driven inward chloride pump, halorhodopsin, which enabled them to be rapidly and reversibly activated or inhibited by pulses of light. These light responsive tools provide a spatially and temporally precise means of studying how different cell types contribute to information processing in cortical circuits. Our customized optrodes and optical commutators for in vivo recording allow for efficient light delivery and recording and can be requested at www.neuro-­cloud.net/nature-precedings/baratta
- …