2,954 research outputs found
The Effects of Perceived Overqualification on Job Satisfaction, Organizational Commitment, and Turnover: A Study of AFIT Graduates
The U.S. Air Force provides multiple program to increase the educational skills of its workforce. This study focuses on the Air Force Institute of Technology (AFIT) graduate level, in-residence degree program. The Air Force is making a significant investment in the education of its members. Studies on perceived overqualification, overeducation, and match quality suggest that utilization plays a role in an individual\u27s job satisfaction and organizational commitment. Job satisfaction and organizational commitment levels can be used as predictors of turnover. This research studies the levels of perceived overqualification in AFIT graduates and how it effects their job satisfaction, organizational commitment, and turnover. Data for this research was collected using an on-line survey tool, Facilitate.com. Analysis indicates that US Air Force officers who perceived that they were overqualified for their AFIT follow-on assignment did experience lower levels of job satisfaction and organizational commitment. The hypotheses, results, and analysis of this study are presented along with recommendations and suggestions for future research
Beating the blackberry
The blackberry is an aggressive, strongly-growing plant that has spread throughout parts of the south-west of Western Australia.
Although most blackberry infestations on agricultural land have been dramatically reduced since compulsory control measures were introduced 30 years ago, about 3,600 hectares are still infested today.
Recent research has shown that three new herbicides are highly effective against blackberry, and much safer to use than the older ones.
Effective biological control of blackberry may also be possible
Drosophila by the dozen
A report of the 48th Annual Drosophila Research Conference, Philadelphia, USA, 7-11 March 2007
Cereal weed control, Cereal disease, Roundup effects on wheat & barley, Noxious weed control.
Pre-seeding Grass Control, 85AL41. Sorrel control with Ally, 85AL39. Capeweed control pre-seeding, 85AL40. Effect of PP 450 on wheat diseases, 83AL36. Roundup effects on wheat and barley, 85AL64. History effects on wheat responses, 85AL42. Garlon 480 time of spraying on blackberry. Blackberry herbicide (high volume) demonstrations and observations. Blackberry herbicide (low volume) demo sites. Comparison of sprayers and spray volume for blackberry control. Blackberry herbicides screening. Krenite on blackberry, 76 AL 8. Methods of Krenite application for blackberry Control. Blackberry Wettability. Ropewick applied 2,4-D Amine for Arum Lily control. Arum lily herbicide screening. Herbicide screening for Arum lily control. Herbicide screening on gorse
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A Lagrangian analysis of ice-supersaturated air over the North Atlantic
Understanding the nature of air parcels that exhibit ice-supersaturation is important because they are the regions of potential formation of both cirrus and aircraft contrails, which affect the radiation balance. Ice-supersaturated air parcels in the upper troposphere and lower stratosphere over the North Atlantic are investigated using Lagrangian trajectories. The trajectory calculations use ERA-Interim data for three winter and three summer seasons, resulting in approximately 200,000 trajectories with ice-supersaturation for each season. For both summer and winter, the median duration of ice-supersaturation along a trajectory is less than 6 hours. 5% of air which becomes ice-supersaturated in the troposphere, and 23% of air which becomes ice-supersaturated in the stratosphere will remain ice-supersaturated for at least 24 hours. Weighting the ice-supersaturation duration with the observed frequency indicates the likely overall importance of the longer duration ice-supersaturated trajectories. Ice-supersaturated air parcels typically experience a decrease in moisture content while ice-supersaturated, suggesting that cirrus clouds eventually form in the majority of such air. A comparison is made between short-lived (less than 24 h) and long-lived (greater than 24 h) ice-supersaturated air flows. For both air flows, ice-supersaturation occurs around the northernmost part of the trajectory. Short-lived ice-supersaturated air flows show no significant differences in speed or direction of movement to subsaturated air parcels. However, long-lived ice-supersaturated air occurs in slower moving air flows, which implies that they are not associated with the fastest moving air through a jet stream
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The counter-propagating Rossby-wave perspective on baroclinic instability. Part III: Primitive-equation disturbances on the sphere
Baroclinic instability of perturbations described by the linearized primitive quations, growing on steady zonal jets on the sphere, can be understood in terms of the interaction of pairs of counter-propagating Rossby waves (CRWs). The CRWs can be viewed as the basic components of the dynamical system where the Hamiltonian is the pseudoenergy and each CRW has a zonal coordinate and pseudomomentum. The theory holds for adiabatic frictionless flow to the extent that truncated forms of pseudomomentum and pseudoenergy are globally conserved. These forms focus attention on Rossby wave activity. Normal mode (NM) dispersion relations for realistic jets are explained in terms of the two CRWs associated with each unstable NM pair. Although derived from the NMs, CRWs have the conceptual advantage that their structure is zonally untilted, and can be anticipated given only the basic state. Moreover, their zonal propagation, phase-locking and mutual interaction can all be understood by ‘PV-thinking’ applied at only two ‘home-bases’—potential vorticity (PV) anomalies at one home-base induce circulation anomalies, both locally and at the other home-base, which in turn can advect the PV gradient and modify PV anomalies there. At short wavelengths the upper CRW is focused in the mid-troposphere just above the steering level of the NM, but at longer wavelengths the upper CRW has a second wave-activity maximum at the tropopause. In the absence of meridional shear, CRW behaviour is very similar to that of Charney modes, while shear results in a meridional slant with height of the air-parcel displacement-structures of CRWs in sympathy with basic-state zonal angular-velocity surfaces. A consequence of this slant is that baroclinically growing eddies (on jets broader than the Rossby radius) must tilt downshear in the horizontal, giving rise to up-gradient momentum fluxes that tend to accelerate the barotropic component of the jet
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The counter-propagating Rossby-wave perspective on baroclinic instability. Part IV: Nonlinear life cycles
Pairs of counter-propagating Rossby waves (CRWs) can be used to describe baroclinic instability in linearized primitive-equation dynamics, employing simple propagation and interaction mechanisms at only two locations in the meridional plane—the CRW ‘home-bases’. Here, it is shown how some CRW properties are remarkably robust as a growing baroclinic wave develops nonlinearly. For example, the phase difference between upper-level and lower-level waves in potential-vorticity contours, defined initially at the home-bases of the CRWs, remains almost constant throughout baroclinic wave life cycles, despite the occurrence of frontogenesis and Rossby-wave breaking. As the lower wave saturates nonlinearly the whole baroclinic wave changes phase speed from that of the normal mode to that of the self-induced phase speed of the upper CRW. On zonal jets without surface meridional shear, this must always act to slow the baroclinic wave. The direction of wave breaking when a basic state has surface meridional shear can be anticipated because the displacement structures of CRWs tend to be coherent along surfaces of constant basic-state angular velocity, U. This results in up-gradient horizontal momentum fluxes for baroclinically growing disturbances. The momentum flux acts to shift the jet meridionally in the direction of the increasing surface U, so that the upper CRW breaks in the same direction as occurred at low level
Rossby wave dynamics of the North Pacific extra-tropical response to El Niño: importance of the basic state in coupled GCMs
The extra-tropical response to El Nino in a "low" horizontal resolution coupled climate model, typical of the Intergovernmental Panel on Climate Change fourth assessment report simulations, is shown to have serious systematic errors. A high resolution configuration of the same model has a much improved response that is similar to observations. The errors in the low resolution model are traced to an incorrect representation of the atmospheric teleconnection mechanism that controls the extra-tropical sea surface temperatures (SSTs) during El Nino. This is due to an unrealistic atmospheric mean state, which changes the propagation characteristics of Rossby waves. These erroneous upper tropospheric circulation anomalies then induce erroneous surface circulation features over the North Pacific. The associated surface wind speed and direction errors create erroneous surface flux and upwelling anomalies which finally lead to the incorrect extra-tropical SST response to El Nino in the low resolution model. This highlights the sensitivity of the climate response to a single link in a chain of complex climatic processes. The correct representation of these processes in the high resolution model indicates the importance of horizontal resolution in resolving such processes
The effect of a sports chiropractic manual therapy intervention on the prevention of back pain, hamstring and lower limb injuries in semi-elite Australian Rules footballers: a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Hamstring injuries are the most common injury in Australian Rules football. It was the aims to investigate whether a sports chiropractic manual therapy intervention protocol provided in addition to the current best practice management could prevent the occurrence of and weeks missed due to hamstring and other lower-limb injuries at the semi-elite level of Australian football.</p> <p>Methods</p> <p>Sixty male subjects were assessed for eligibility with 59 meeting entry requirements and randomly allocated to an intervention (n = 29) or control group (n = 30), being matched for age and hamstring injury history. Twenty-eight intervention and 29 control group participants completed the trial. Both groups received the current best practice medical and sports science management, which acted as the control. Additionally, the intervention group received a sports chiropractic intervention. Treatment for the intervention group was individually determined and could involve manipulation/mobilization and/or soft tissue therapies to the spine and extremity. Minimum scheduling was: 1 treatment per week for 6 weeks, 1 treatment per fortnight for 3 months, 1 treatment per month for the remainder of the season (3 months). The main outcome measure was an injury surveillance with a missed match injury definition.</p> <p>Results</p> <p>After 24 matches there was no statistical significant difference between the groups for the incidence of hamstring injury (OR:0.116, 95% CI:0.013-1.019, p = 0.051) and primary non-contact knee injury (OR:0.116, 95% CI:0.013-1.019, p = 0.051). The difference for primary lower-limb muscle strains was significant (OR:0.097, 95%CI:0.011-0.839, p = 0.025). There was no significant difference for weeks missed due to hamstring injury (4 v14, χ2:1.12, p = 0.29) and lower-limb muscle strains (4 v 21, χ2:2.66, p = 0.10). A significant difference in weeks missed due to non-contact knee injury was noted (1 v 24, χ2:6.70, p = 0.01).</p> <p>Conclusions</p> <p>This study demonstrated a trend towards lower limb injury prevention with a significant reduction in primary lower limb muscle strains and weeks missed due to non-contact knee injuries through the addition of a sports chiropractic intervention to the current best practice management.</p> <p>Trial registration</p> <p>The study was registered with the Australian and New Zealand Clinical Trials Registry (ACTRN12608000533392).</p
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