16,271 research outputs found
Absolute quantum energy inequalities in curved spacetime
Quantum Energy Inequalities (QEIs) are results which limit the extent to
which the smeared renormalised energy density of the quantum field can be
negative, when averaged along a timelike curve or over a more general timelike
submanifold in spacetime. On globally hyperbolic spacetimes the
minimally-coupled massive quantum Klein--Gordon field is known to obey a
`difference' QEI that depends on a reference state chosen arbitrarily from the
class of Hadamard states. In many spacetimes of interest this bound cannot be
evaluated explicitly. In this paper we obtain the first `absolute' QEI for the
minimally-coupled massive quantum Klein--Gordon field on four dimensional
globally hyperbolic spacetimes; that is, a bound which depends only on the
local geometry. The argument is an adaptation of that used to prove the
difference QEI and utilises the Sobolev wave-front set to give a complete
characterisation of the singularities of the Hadamard series. Moreover, the
bound is explicit and can be formulated covariantly under additional (general)
conditions. We also generalise our results to incorporate adiabatic states.Comment: 31 pages. Corrections and clarifications added. Final version to
appear in Ann. H. Poincar
ILR Impact Brief - Pathways to Success: Human Resource Practices Do Matter
[Extract] Most researchers agree that human resource (HR) practices affect attitudes and discretionary behavior on the job and that employee actions and motivations influence company performance. The academic literature also suggests that investing in employees, through high-commitment HR practices such as internal labor markets, selecting new employees who “fit” the company rather than a particular job, compensating employees on the basis of group and company results, and training and development programs that stress team building and long-term growth, are all indirectly related to organizational success. Missing from the literature is an exploration of the causal mechanisms that mediate between these HR practices and favorable outcomes for companies operating in dynamic environments; this research begins filling the void
Session:management of drainage near source – disconnection/minimise surface water entering public drainage
Many combined sewer networks are currently constrained due to lack of capacity. Surface water entering the network may have an impact on the local environment by causing additional spills from Combined Sewer Overflows (CSOs) and flooding events. With the increasing number of developments taking place in Scotland, more and more demands are being placed upon the existing wastewater assets and infrastructure of the drainage utility, Scottish Water. The principal way of preventing these CSO spills/flooding event s is to reduce the number of surface water connections to the combined sewer network and promote more surface water discharges to nearby watercourses.The problem is being addressed by examining all development applications as they are considered by a drainage planning officer in the water authority. The research reported in this paper is investigating the conditions under which it is reasonable and practical for Scottish Water to accept surface water flows into its combined sewer network . This paper presents a summary of the initial findings of the research to date by examining a sample of the sites examined. The objective of the work is to develop a methodology to support a rigorous stance on the acceptance of surface water flows into the combined sewer network. The results have not as yet been obtained
Human Resource Practices, Knowledge-Creation Capability And Performance In High Technology Firms
This study examines the relationship among key HR practices (i.e., effective acquisition, employee-development, commitment-building, and networking practices), three dimensions of knowledge-creation capability (human capital, employee motivation, and information combination and exchange), and firm performance. Results from a sample of 78 high technology firms showed that the three dimensions of knowledge creation interact to positively affect sales growth. Further, the HR practices were found to affect sales growth through their affect on the dimensions of knowledge-creation capability
Support for Drought Response and Community Preparedness: Filling the Gaps between Plans and Action
This chapter examines which levels of government handle various aspects of drought, as well as interactions between levels of government, providing examples from states across the western United States. It also takes a look at aspects of drought that fall outside traditional lines of authority and disciplinary boundaries. As part of a discussion on how states support local drought response, the chapter details and contrasts how California and Colorado track public water supply restrictions, and describes Colorado’s process for incorporating input from river basins across the state into its water plan. Case studies focus on drought planning in the Klamath River and Upper Colorado River basins through the lens of collaborative environmental planning. The chapter concludes that drought planning will be more effective as more states coordinate and align goals and policies at multiple levels of government
Epistemological Problems In Planning
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145225/1/anti19724123.pd
Stress Fractures of the Elbow in the Throwing Athlete: A Systematic Review.
Background: Stress fractures of the elbow are rare in throwing athletes and present a challenge from both a management and rehabilitation perspective. Although the incidence of stress fractures of the elbow is increasing, there is a lack of data in the literature focused on throwers.
Purpose: To evaluate studies regarding the management and outcomes of stress fractures of the elbow in throwing athletes.
Study Design: Systematic review; Level of evidence, 4.
Methods: A systematic review was conducted by searching the Scopus, PubMed, and Cochrane Library electronic databases to identify studies reporting on the management and outcomes of stress fractures in overhead-throwing athletes. Management data included nonoperative and operative modalities, and outcome data included return to play, encompassing the timing and level of activity. Studies were excluded if the stress fracture of the elbow was not a result of a sport injury attributed to throwing or if the study failed to report whether an athlete returned to play.
Results: Fourteen studies met the inclusion criteria and were included in this analysis. There were 52 patients in total (50 male, 2 female) with a mean age of 19.7 years (range, 13-29.1 years). The olecranon was the most common location of the stress fracture (51 patients; 98.1%), followed by the distal humerus (1 patient; 1.9%). The majority of patients (n = 40; 76.9%) were treated operatively. Of the 40 patients who were treated surgically, 14 (35.0%) underwent a period of conservative treatment preoperatively that ultimately failed because of persistent nonunion or continued elbow pain. A total of 50 patients (96.2%) returned to sport either at or above their preinjury level. Of the 2 patients (3.8%) who did not return to sport, 1 did not return because of continued elbow pain postoperatively, and the other was lost to follow-up. Complications occurred in 9 patients (17.3%), all of whom were treated surgically.
Conclusion: On the basis of this systematic review, the majority of elbow stress fractures were treated operatively and approximately one-third after a period of failed nonoperative management. The return-to-sport rate was high. Further, higher level studies are needed to optimize management and return-to-sport rates in this population
DPSIR-Two decades of trying to develop a unifying framework for marine environmental management?
© 2016 PatrĂcio, Elliott, Mazik, Papadopoulou and Smith. Determining and assessing the links between human pressures and state-changes in marine and coastal ecosystems remains a challenge. Although there are several conceptual frameworks for describing these links, the Drivers-Pressures-State change-Impact-Response (DPSIR) framework has been widely adopted. Two possible reasons for this are: either the framework fulfills a major role, resulting from convergent evolution, or the framework is used often merely because it is used often, albeit uncritically. This comprehensive review, with lessons learned after two decades of use, shows that the approach is needed and there has been a convergent evolution in approach for coastal and marine ecosystem management. There are now 25 derivative schemes and a widespread and increasing usage of the DPSIR-type conceptual framework as a means of structuring and analyzing information in management and decision-making across ecosystems. However, there is less use of DPSIR in fully marine ecosystems and even this was mainly restricted to European literature. Around half of the studies are explicitly conceptual, not illustrating a solid case study. Despite its popularity since the early 1990s among the scientific community and the recommendation of several international institutions (e.g., OECD, EU, EPA, EEA) for its application, the framework has notable weaknesses to be addressed. These primarily relate to the long standing variation in interpretation (mainly between natural and social scientists) of the different components (particularly P, S, and I) and to over-simplification of environmental problems such that cause-effect relationships cannot be adequately understood by treating the different DPSIR components as being mutually exclusive. More complex, nested, conceptual models and models with improved clarity are required to assess pressure-state change links in marine and coastal ecosystems. Our analysis shows that, because of its complexity, marine assessment and management constitutes
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