4,754 research outputs found
Putting Quality Back in the Forest
A FEW YEARS ago one of our best known radio commentators was flying from Florida 1to New York. Chancing to look down upon the green earth, he was seized with inspiration. That night, over a national network, he waxed lyrical âąto millions about the vast forests he had gazed upon and the solid reassurance they have given him - from a couple of miles up - of our country\u27s luxuriant timber resources
The Rise and Fall of Water Net (Hydrodictyon reticulatum) in New Zealand
During the late 1980s to early 1990s a range of aquatic habitats in the central North Island of New Zealand were invaded by the filamentous green alga, water net Hydrodictyon reticulatum (Linn. Lagerheim). The alga caused significant economic and recreational impacts at major sites of infestation, but it was also associated with enhanced invertebrate numbers and was the likely cause of an improvement in the trout fishery. The causes of prolific growth of water net and the range of control options pursued are reviewed. The possible causes of its sudden decline in 1995 are considered, including physical factors, increase in grazer pressure, disease, and loss of genetic vigour
Efficient Refocussing of One Spin and Two Spin Interactions for NMR Quantum Computation
The use of spin echoes to refocus one spin interactions (chemical shifts) and
two spin interactions (spin-spin couplings) plays a central role in both
conventional NMR experiments and NMR quantum computation. Here we describe
schemes for efficient refocussing of such interactions in both fully and
partially coupled spin systems.Comment: 4 pages, RevTeX, including 4 LaTeX figure
Solving Large-Scale Optimization Problems Related to Bell's Theorem
Impossibility of finding local realistic models for quantum correlations due
to entanglement is an important fact in foundations of quantum physics, gaining
now new applications in quantum information theory. We present an in-depth
description of a method of testing the existence of such models, which involves
two levels of optimization: a higher-level non-linear task and a lower-level
linear programming (LP) task. The article compares the performances of the
existing implementation of the method, where the LPs are solved with the
simplex method, and our new implementation, where the LPs are solved with a
matrix-free interior point method. We describe in detail how the latter can be
applied to our problem, discuss the basic scenario and possible improvements
and how they impact on overall performance. Significant performance advantage
of the matrix-free interior point method over the simplex method is confirmed
by extensive computational results. The new method is able to solve problems
which are orders of magnitude larger. Consequently, the noise resistance of the
non-classicality of correlations of several types of quantum states, which has
never been computed before, can now be efficiently determined. An extensive set
of data in the form of tables and graphics is presented and discussed. The
article is intended for all audiences, no quantum-mechanical background is
necessary.Comment: 19 pages, 7 tables, 1 figur
Effective theory for wall-antiwall system
We propose a useful method for deriving the effective theory for a system
where BPS and anti-BPS domain walls coexist. Our method respects an
approximately preserved SUSY near each wall. Due to the finite width of the
walls, SUSY breaking terms arise at tree-level, which are exponentially
suppressed. A practical approximation using the BPS wall solutions is also
discussed. We show that a tachyonic mode appears in the matter sector if the
corresponding mode function has a broader profile than the wall width.Comment: LaTeX file, 30 page, 5 eps figures, references adde
The Problem of the Stabilization of the Dilaton in String Theories
The crucial problem of how the dilaton field is stabilized at a
phenomenologically acceptable value in string theories remains essentially
unsolved. We show that the usual scenario of assuming that the dilaton is fixed
by the (SUSY breaking) dynamics of just the dilaton itself (dilaton dominance
scenario) is {\em inconsistent} unless the K\"ahler potential receives very
important perturbative or non-perturbative contributions. Then, the usual
predictions about soft breaking terms are lost, but still is possible to derive
model-independent predictions for them.Comment: 7 pages, LaTeX. Talk given at SUSY-96, Univ. of Maryland, College
Park, May 29 - June 1, 199
Vacuum Stability Higgs Mass Bound Revisited with Implications for Extra Dimension Theories
We take the standard model to be an effective theory including higher
dimensional operators suppressed by scale and re-examine the higgs
mass bounds from the requirements of vacuum stability. Our results show that
the effects of the higher dimensional operators on the higgs mass limits are
significant. As an implication of our results, we study the vacuum stability
higgs mass bounds in theories with extra dimensions.Comment: Latex, 14 pages, 1 figure. Added references. To appear in Phys. Rev.
Establishing a high performing culture in an emerging rugby nation
Building and sustaining effective high performing team cultures has been at the forefront of sport research for a number of years. Findings from elite level teams, talent development and collegiate environments share several key features of effective high performing cultures that include a clear vision, strong and adaptable leadership, daily displays of shared winning behaviours and long-term holistic development for example. Although these features â and others - may provide guidance for future theoretical and applied work in these specific domains, there appears a lack of understanding regarding how to build and manage sport team culture in emerging nations. Emerging nations are unique and may experience context specific challenges such as smaller talent pools and less financial and/or resource support for example. Emerging nations may look towards more established environments to mimic best practice, with the movement of coaches from established teams to emerging nations part of this transfer of knowledge. However, although the boundary-less features might be applicable, for a culture to be effective it needs to be the right âfitâ and, due to the specific nuances of teams in emerging nations, directly lifting practices from more established environments may be questionable as the emerging context is ultimately different. Subsequently, and with the aim of increasing the knowledge base of building and sustaining a high performing culture in specific sporting contexts, this thesis aimed to provide pragmatic, evidence-based guidelines for building a high-performing culture in an emerging rugby nation, with three key objectives: 1. To examine and evaluate the creation of a high performing culture within an existing emerging rugby nation 2. Given the global nature of todayâs sporting landscape, to investigate best practice in nurturing a high performing culture within multicultural teams and as a foreign coach 3. To investigate the âopposite poleâ of best practice to highlight what should be avoided when building a high performing culture as a foreign coach. These objectives were met through chapters three to six. The first phase of the research included two studies (chapters three and four) that addressed the first objective. Chapter Three, to the researcherâs knowledge was the first study of its kind in examining an emerging rugby nationâs team culture. Eleven full time professional male rugby union players, the Head of the Hong Kong Rugby Unionâs (HKRU) Elite Rugby Program (ERP) and the HKRUâs peripatetic sport psychologist were interviewed. Through the unique theoretical lens of combining Performance Management and the Resource Based View, inductive thematic analysis of semistructured interview data revealed five emerging themes, namely, 1) an amateur environment that required change; 2) ERPâs professional culture building blocks; 3) leadership strategy and managing key stake holders; 4) evidencing and reenforcing the change and 5) managing ongoing challenges in the ERPâs professional culture. Theoretical and applied implications for practitioners and program leaders responsible for driving cultural change in their respective emerging environments were revealed. Following the unique qualitative insight into the development of the ERPâs team culture over a four-year period, ascertained in study one, study two, in further meeting the thesisâs first objective, aimed to quantitatively examine the current status of the ERPâs culture. Triangulating the findings from the previous study, the specific aim for study two was to quantitatively evaluate the evidence-based features of an effective rugby talent development culture in Hong Kong. The cultural tool used for this purpose was Martindale et alâs. (2010) Talent Development Environment Questionnaire (TDEQ). Although not an explicit cultural assessment tool, the TDEQ appeared to be appropriate for this current sport context due to; 1) its focus on identifying environmental strengths and weaknesses to inform intervention needs; 2) its factors and items are representative of effective TDE culture in sport and 3) the evidence of strong ecological validity and reliability in this context and its applicability through a range of sports. Results from the TDEQ indicated a number of current cultural strengths of the ERP; such as the regularity with which playersâ performances were reviewed; the effectiveness of the integrated, accessible and approachable support staff; the robust planning of training and training content and the extent with which playersâ dual careers were developed through the ERPâs âEarn or Learnâ scheme. There were also a number of items that were identified by the players as areas that required improvement. These individual items were themed to help shape potential intervention strategies. The four themes were 1) role models and peer pressure; 2) forward planning and welfare; 3) clarity of required process focus and 4) player empowerment. In meeting the first objective the combination of findings from the first phase of the thesis provided a more rounded understanding of the ERPâs team culture. In meeting the second objective and increasing the paucity of knowledge in how elite coaches acculturate and how they manage their acculturation environment, study three was carried out. This study was again unique in its examination of the acculturation experiences of elite rugby union coaches and their management of multi-cultural squads. Five male elite coaches participated in the research. Each of the five coaches arguably fit a âbest of the bestâ criterion, boasting between them multiple European and UK domestic championships as well as multiple Super Rugby titles with similar accomplishments at international level across fifteen and seven-a-side. Using Berryâs (1997) Framework for Acculturation, inductive thematic analysis of semi-structured interview data revealed two emerging themes, a) proactively managing personal acculturation and b) pro-actively managing player acculturation. Implications for coaches managing their own acculturation experience and their respective acculturation environments are discussed with findings synthesised for the emerging context. Finally, in meeting the third objective, study four examined the âopposite poleâ of best coaching practice and, developing the knowledge surrounding failures of sport leaders, examined the failure of an elite rugby union coaching team through the specific lens of leadership derailment. This study was another unique contribution to the literature given there were no prior reported studies of leadership/coach derailment in sport. Eleven male elite rugby union players participated in the research all of whom were part of the playing squad during the failed season in question. Data from semi structured interviews was abductively analysed and revealed previously established derailment factors that were pivotal to the derailment of the coaching team; namely, problems with interpersonal relationships, an inability to lead the team, an inability to adapt and change; too narrow a functional orientation and a failure to meet performance objectives. By examining these findings, several unique contributions that offer both theoretical and applied advances in the âopposite poleâ of sport coach leadership were presented. In keeping with the pragmatic philosophy adopted throughout the thesis, with the aim of providing real world solutions to specific problems (Giacobbi et al., 2005), practical guidelines emanating from the four studies, combined with researcher reflections, were provided for coaches of teams within emerging nations to help steer future direction in the creation and development of high performing cultures
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