Performance Analysis of Heat Sinks With Phase-Change Materials Subjected to Transient and Cyclic Heating

Phase-change cooling technique is a suitable method for thermal management of electronic equipment subjected to transient or cyclic heat loads. The thermal performance of a phase-change based heat sink under cyclic heat load depends on several design parameters, namely, applied heat flux, cooling heat transfer coefficient, thermophysical properties of phase-change materials (PCMs), and physical dimensions of phase-change storage system during melting and freezing processes. A one-dimensional conduction heat transfer model is formulated to evaluate the effectiveness of preliminary design of practical PCM-based energy storage units. In this model, the phase-change process of the PCM is divided into melting and solidification subprocesses, for which separate equations are written. The equations are solved sequentially and an explicit closed-form solution is obtained. The efficacy of analytical model is estimated by comparing with a finite-volume-based numerical solution for both transient and cyclic heat loads.

Study on spatial pattern of land-use change in China during 1995-2000

It is more and more acknowledged that land-use/cover dynamic change has become a key subject urgently to be dealt with in the study of global environmental change. Supported by the Landsat TM digital images, spatial patterns and temporal variation of land-use change during 1995 -2000 are studied in the paper. According to the land-use dynamic degree model, supported by the 1km GRID data of land-use change and the comprehensive characters of physical, economic and social features, a dynamic regionalization of land-use change is designed to disclose the spatial pattern of land-use change processes. Generally speaking, in the traditional agricultural zones, e.g., Huang-Huai-Hai Plains, Yangtze River Delta and Sichuan Basin, the built-up and residential areas occupy a great proportion of arable land, and in the interlock area of farming and pasturing of northern China and the oases agricultural zones, the reclamation I of arable land is conspicuously driven by changes of production conditions, economic benefits and climatic conditions. The implementation of "returning arable land into woodland or grassland" policies has won initial success in some areas, but it is too early to say that the trend of deforestation has been effectively reversed across China. In this paper, the division of dynamic regionalization of land-use change is designed, for the sake of revealing the temporal and spatial features of land-use change and laying the foundation for the study of regional scale land-use changes. Moreover, an integrated study, including studies of spatial pattern and temporal process of land-use change, is carried out in this paper, which is an interesting try on the comparative studies of spatial pattern on change process and the change process of spatial pattern of land-use change.

Luminescence centers and valence change of Eu2+ in KCaF3

The nature of the emission centers and the valence change of Eu2+ in KCaF3:Eu2+ depends strongly on preparation conditions. Experimental results show that there are two different d-->f emission bands, located at 425 and 510 nm, respectively. Their origin, relationship, and the effect of doping concentration on them are discussed. A Eu2+-Eu3+ valence change process is proposed. (C) 2000 Elsevier Science Ltd. All rights reserved.

The effects of blood pressure lowering on development of cognitive impairment and dementia in patients without apparent prior cerebrovascular disease

BACKGROUND: Hypertension and cognitive impairment are prevalent in older people. It is known that hypertension is a direct risk factor for vascular dementia and recent studies have suggested hypertension also impacts upon prevalence of Alzheimer's disease. The question is therefore whether treatment of hypertension lowers the rate of cognitive decline. OBJECTIVES: To assess the effects of blood pressure lowering treatments for the prevention of dementia and cognitive decline in patients with hypertension but no history of cerebrovascular disease. SEARCH STRATEGY: The trials were identified through a search of CDCIG's Specialised Register, CENTRAL, MEDLINE, EMBASE, PsycINFO and CINAHL on 27 April 2005. SELECTION CRITERIA: Randomized, double-blind, placebo controlled trials in which pharmacological or non-pharmacological interventions to lower blood pressure were given for at least six months. DATA COLLECTION AND ANALYSIS: Two independent reviewers assessed trial quality and extracted data. The following outcomes were assessed: incidence of dementia, cognitive change from baseline, blood pressure level, incidence and severity of side effects and quality of life. MAIN RESULTS: Three trials including 12,091 hypertensive subjects were identified. Average age was 72.8 years. Participants were recruited from industrialised countries. Mean blood pressure at entry across the studies was 170/84 mmHg. All trials instituted a stepped care approach to hypertension treatment, starting with a calcium-channel blocker, a diuretic or an angiotensin receptor blocker. The combined result of the three trials reporting incidence of dementia indicated no significant difference between treatment and placebo (Odds Ratio (OR) = 0.89, 95% CI 0.69, 1.16). Blood pressure reduction resulted in a 11% relative risk reduction of dementia in patients with no prior cerebrovascular disease but this effect was not statistically significant (p = 0.38) and there was considerable heterogeneity between the trials. The combined results from the two trials reporting change in Mini Mental State Examination (MMSE) did not indicate a benefit from treatment (Weighted Mean Difference (WMD) = 0.10, 95% CI -0.03, 0.23). Both systolic and diastolic blood pressure levels were reduced significantly in the two trials assessing this outcome (WMD = -7.53, 95% CI -8.28, -6.77 for systolic blood pressure, WMD = -3.87, 95% CI -4.25, -3.50 for diastolic blood pressure).Two trials reported adverse effects requiring discontinuation of treatment and the combined results indicated a significant benefit from placebo (OR = 1.18, 95% CI 1.06, 1.30). When analysed separately, however, more patients on placebo in SCOPE were likely to discontinue treatment due to side effects; the converse was true in SHEP 1991. Quality of life data could not be analysed in the three studies. There was difficulty with the control group in this review as many of the control subjects received antihypertensive treatment because their blood pressures exceeded pre-set values. In most cases the study became a comparison between the study drug against a usual antihypertensive regimen. AUTHORS' CONCLUSIONS: There was no convincing evidence from the trials identified that blood pressure lowering prevents the development of dementia or cognitive impairment in hypertensive patients with no apparent prior cerebrovascular disease. There were significant problems identified with analysing the data, however, due to the number of patients lost to follow-up and the number of placebo patients given active treatment. This introduced bias. More robust results may be obtained by analysing one year data to reduce differential drop-out or by conducting a meta-analysis using individual patient data.

'Ulster's policing goes global': The police reform process in Northern Ireland and the creation of a global brand

This paper engages with contemporary discussions in relation to the commodification of policing and security. It suggests that the existing literature regarding these trends has been geared primarily towards commercial security providers and has failed to address the processes by which public policing models are commodified and marketed both within, and through, the transnational policing community. Drawing upon evidence from the police change process in Northern Ireland, we argue that a Northern Irish Policing Model (NIPM) has emerged in the aftermath of the Independent Commission on Policing (ICP) reforms. This is increasingly branded and promoted on the global stage. Furthermore, we suggest that the NIPM is not monolithic, but segmented, and targeted towards a number of different 'consumers' both domestically and transnationally. Reflecting these diverse markets, the NIPM draws upon two seemingly incongruous constituent elements: the 'best practice' lessons of policing transition, as embodied in the ICP reforms; and, the legacy of counter-terrorism expertise drawn from the preceding decades of conflict. The discussion concludes by querying as to which of these components of the NIPM is in the ascendancy.

Blood pressure lowering in patients without prior cerebrovascular disease for prevention of cognitive impairment and dementia

Background: This is an update of a previous review (McGuinness 2006). Hypertension and cognitive impairment are prevalent in older people. Hypertension is a direct risk factor for vascular dementia (VaD) and recent studies have suggested hypertension impacts upon prevalence of Alzheimer's disease (AD). Therefore does treatment of hypertension prevent cognitive decline?
Objectives: To assess the effects of blood pressure lowering treatments for the prevention of dementia and cognitive decline in patients with hypertension but no history of cerebrovascular disease.
Search strategy: The Specialized Register of the Cochrane Dementia and Cognitive Improvement Group, The Cochrane Library, MEDLINE, EMBASE, PsycINFO, CINAHL, LILACS as well as many trials databases and grey literature sources were searched on 13 February 2008 using the terms: hypertens$ OR anti-hypertens$. Selection criteria: Randomized, double-blind, placebo controlled trials in which pharmacological or non-pharmacological interventions to lower blood pressure were given for at least six months.
Data collection and analysis: Two independent reviewers assessed trial quality and extracted data. The following outcomes were assessed: incidence of dementia, cognitive change from baseline, blood pressure level, incidence and severity of side effects and quality of life.
Main results: Four trials including 15,936 hypertensive subjects were identified. Average age was 75.4 years. Mean blood pressure at entry across the studies was 171/86 mmHg. The combined result of the four trials reporting incidence of dementia indicated no significant difference between treatment and placebo (236/7767 versus 259/7660, Odds Ratio (OR) = 0.89, 95% CI 0.74, 1.07) and there was considerable heterogeneity between the trials. The combined results from the three trials reporting change in Mini Mental State Examination (MMSE) did not indicate a benefit from treatment (Weighted Mean Difference (WMD) = 0.42, 95%CI 0.30, 0.53). Both systolic and diastolic blood pressure levels were reduced significantly in the three trials assessing this outcome (WMD = -10.22, 95% CI -10.78, -9.66 for systolic blood pressure, WMD = -4.28, 95% CI -4.58, -3.98 for diastolic blood pressure). Three trials reported adverse effects requiring discontinuation of treatment and the combined results indicated no significant difference (OR = 1.01, 95% CI 0.92, 1.11). When analysed separately, however, more patients on placebo in Syst Eur 1997 were likely to discontinue treatment due to side effects; the converse was true in SHEP 1991. Quality of life data could not be analysed in the four studies. Analysis of the included studies in this review was problematic as many of the control subjects received antihypertensive treatment because their blood pressures exceeded pre-set values. In most cases the study became a comparison between the study drug against a usual antihypertensive regimen.
Authors' conclusions: There is no convincing evidence fromthe trials identified that blood pressure lowering in late-life prevents the development of dementia or cognitive impairment in hypertensive patients with no apparent prior cerebrovascular disease. There were significant problems identified with analysing the data, however, due to the number of patients lost to follow-up and the number of placebo patients who received active treatment. This introduced bias. More robust results may be obtained by conducting a meta-analysis using individual patient data.

Tracking Change in Northern Ireland Policing: Temporal Phases and Key Themes

Purpose
– The purpose of this paper is to explore and explain the change process in Northern Ireland policing through an analysis of temporally bracketed change phases and key change delivery themes ranging from 1996 to 2012.

Design/methodology/approach
– The research approach adopted is process based, longitudinal and multi-method, utilising “temporal bracketing” to determine phases of change and conjunctural reasoning to unravel the systematic factors interacting over time, within the case.

Findings
– The paper identifies and temporally brackets four phases of change: “Tipping point”; “Implementation, Symbolic Modification and Resistance”; “Power Assisted Steering”; and “A Return to Turbulence”, identifies four themes that emerge from RUC-PSNI experience: the role of adaptive leadership; pace and sequencing of change implementation; sufficient resourcing; and the impact of external agents acting as boundary spanners, and comments on the prominence of these themes through the phases. The paper goes on to reflect upon how these phases and themes inform our understanding of organisational change within policing organisations generally and within politically pressurised transition processes.

Originality/value
– The contribution of the paper lies in the documentation of an almost unique organisational case in an environmentally forced change process. In this it contains lessons for other organisations facing similar, if less extreme challenges and presents an example of intense change analysed longitudinally.

Symposium - Organisational transformation in policing: Leadership and change in extreme contexts

Nearly 4000 people died in Northern Ireland’s long running conflict, 314 of them police officers (Brewer and Magee 1991, Brewer 1996, Hennessey 1999, Guelke and Milton-Edwards 2000). The republican and loyalist ceasefires of 1994 were the first significant signal that NI society was moving beyond the ‘troubles’ and towards a normalised political environment. The Belfast (Good Friday) Agreement of 1998 cemented that movement (Hennessey 1999). Policing was a key and seemingly unresolvable element of the conflict, seen as unrepresentative and partisan. Its reform or ‘recasting’ in a new dispensation was an integral part of the conflict transformation endeavour(Ellison 2010). As one of the most controversial elements of the conflicted past, it had remained outside the Agreement and was subject to a specific commission of interest (1999), generally known as the Patten Commission. The Commission’s far reaching proposals included a change of name, badge and uniform, the introduction of 50/50 recruitment (50% Roman Catholic and 50% other), a new focus on human rights, a new district command and headquarter structure, a review of ‘Special Branch’ and covert techniques, a concern for ‘policing with the community’ and a significant voluntary severance process to make room for new recruits, unconnected with the past history of the organisation(Murphy 2013).

This paper reflects upon the first data collection phase of a long term processual study of organisational change within the Royal Ulster Constabulary / Police Service of Northern Ireland. This phase (1996-2002) covers early organisational change initiation (including the pre-change period) and implementation including the instigation of symbolic changes (name, badge, and crest) and structural changes (new HQ structure and District Command structure). It utilises internal documentation including messages from the organisations leaders, interviews with forty key informants (identified through a combination of snow-balling from referrals by initial contacts, and key interviews with significant individuals), as well as external documentation and commentary on public perceptions of the change. Using a processual lens (Langley, Smallman et al. 2013) it seeks to understand this initial change phase and its relative success in a highly politicised environment.

By engaging key individuals internally and externally, setting up a dedicated change team, adopting a non normative, non urgent, calming approach to dissent, communicating in orthodox and unorthodox ways with members, acknowledging the huge emotional strain of letting go of the organisation’s name and all it embodied, and re-emphasising the role of officers as ‘police first’, rather than ‘RUC first’, the organisations leadership remained in control of a volatile and unhappy organisational body and succeeded in moving it on through this initial phase, even while much of the political establishment lambasted them externally. Three years into this change process the organisation had a new name, a new crest, new structures, procedures and was deeply engaged in embedding the joint principles of human rights and community policing within its re-woven fabric. While significant problems remained, the new Police Service of Northern Ireland had successfully begun a long journey to full community acceptance in a post conflict context.

This case illustrates the significant challenges of leading change under political pressure, with external oversight and no space for failure(Hannah, Uhl-Bien et al. 2009). It empirically reflects the reality of change implementation as messy, disruptive and unpredictable and highlights the significance of political skill and contextual understanding to success in the early stages(Buchanan and Boddy 1992). The implications of this for change theory and the practice of change implementation are explored (Eisenhardt and Graebner 2007) and some conclusions drawn about what such an extreme case tells us about change generally and change implementation under pressure.

Historical Dialogue and Memory in Policing Change: the Case of the Police in Northern Ireland

This paper explores the complex relationship between organisational change and historical dialogue in transitional societies. Using the policing reform process in Northern Ireland as an example, the paper does three things: the first is to explore the ways in which policing changes were understood within the policing organisation and ‘community’ itself. The second is to make use of a processual approach, privileging the interactions of context, process and time within the analysis. Thirdly, it considers this perspective through the relatively new lens of ‘historical dialogue’: understood here as a conversation and an oscillation between the past, present and future through reflections on individual and collective memory. Through this analysis, we consider how members’ understandings of a difficult past (and their roles in it) facilitated and/or impeded the organisations change process. Drawing on a range of interviews with previous and current members of the organisation, this paper sheds new light on how institutions deal with and understand the past as they experience organisational change within the a wider societal transition from conflict to non-violence.

Organizational change: implications of culture and leadership in the transformation to a total quality management paradigm

The study was undertaken to investigate organizational readiness for change to a total quality management (TQM) paradigm as the corporate-wide strategy within a long-term care facility. The focus of the study was on leadership values and organizational cultural characteristics that could either accelerate or impede the change process at The Public Hospital. structurally, the ~tudy included 'three distinct components. The first component examined the management philosophy outlined by Deming (1986) and his contemporary Juran (1989) in order to determine what leadership values best support the new Total Quality Management paradigm. Secondly, this information was compared to present leadership values at The Public Hospital with the purpose of identifying opportunities for improvement within the organization's current culture as the hospital moves toward the desired TQM culture. The final component, a roadmap, was developed to reflect the most appropriate direction for organizational change at The Public Hospital.

Development and/or change of the notion of permanent object and operative causality: empirical evidence in the first year of life

This study examines the notion of permanent object during the first year of life, taking into account the controversy of two approaches about the nature of change: developmental change and cognitive change. Using a longitudinal/cross-sectional design, tasks adapted of the subscale of permanent object and operative causality of the Uzgiris-Hunt Scale (Uzgiris and Hunt, 1975) (Uzgiris & Hunt, 1975) were presented to 110 infants of 0, 3, 6 and 9 months-old, which reside in three cities of Colombia. The results showed three types of strategies: (a) Not resolution; (b) Exploratory and (c) Resolution, which follow different trajectories in children’s performance. This allows affirming that adaptive conquests of the cognitive development stay together with the variety of strategies. Using strategies reveals adjustments and transformations of action programs that consolidate the notion of permanent object not necessarily with age, but with self-regulatory processes. Empirical evidence contributes to the understanding of the relations between the emergence of novelty in the development and performance variability

An in-depth view of the facets, antecedents and effects of leaders’ change competency: lessons from a case study

Leaders across companies initiate and implement change and thus are crucial for successful organizations. This study takes a competency perspective on leaders and investigates the competencies leaders show to facilitate effective change. The article explores the content of the construct of leaders’ change competency and examines its antecedents and effects. We conducted a case study in a German tourism company undergoing a major change process. The study identified (a) distinct content facets regarding the construct of leaders’ change competency along its two dimensions of leaders’ readiness for change and leaders’ change ability; (b) the construct’s antecedents, specifically contextual factors, leaders’ competency potentials, and attitudes toward change; and (c) beneficial effects of leaders’ change competency. The study ends with implications for research and leadership practice as well as suggestions for future studies on leaders’ change competency.

Muscle delta C-13 change in nile tilapia (Oreochromis niloticus) fingerlings fed lants grain-based diets

The effects of grain-based diets from C3 or C4-cycle plants on muscle delta C-13 change process in Nile tilapia (Oreochromis niloticus) fingerlings were investigated. Two groups of sex reversal males Nile tilapia fingerlings were fed with isoproteic (32.0% DP) and isocaloric (3200 kcal DE/kg) diets, differing from each other by their delta C-13. Muscle samples were collected and the carbon isotopic composition was measured. For C4 diet, the formula for the muscle delta C-13 change related to the intake time of a new diet was delta C-13=- 14.88 - 9.2 1 e(-0.0209t) and the half-life (T) of the muscle carbon was 33.2 days. For C3 diet, the formula was delta C-13 = - 25.43 + 8.59e(-0.0533), with T = 13 days. The C3 diet was considered more appropriate based on its palatability and consequent larger food intake than the C4 diet, resulting in an increased muscle delta C-13 change rate. However, for future studies, would be necessary to mix both the C3 and C4 feedstuffs to formulate diets nutritionally appropriated, with contrasting stable isotopes signatures. Tissue delta C-13 change rate is therefore indicated as a promising tool to better understand the biotic and abiotic factors that influence nutrients utilization from the diet and animal growth. (c) 2006 Elsevier B.V. All rights reserved.

Muscle delta C-13 change in Nile tilapia (Oreochromis niloticus): Effects of growth and carbon turnover

The contribution of growth and turnover to the muscle delta C-13 change process was investigated using mathematical models which associate delta C-13 change to time of intake of a new diet or increase in body mass. Two groups of Nile tilapia (Oreochromis niloticus) were fed on diets based on C3 (sigma C-13 = - 25.64 +/- 0.06 parts per thousand) or C4 (delta C-13= -16.01 +/- 0.06 parts per thousand) photosynthetic cycle plants to standardize the muscle delta C-13. After establishing the carbon isotopic equilibrium, fish (mean mass 24.12 +/- 6.79 g) then received the other treatment diet until a new carbon isotopic equilibrium could be established, characterizing T1 (C3-C4) and T2 (C4-C3) treatments. No significant differences were observed in fish productive performance. Good fits were obtained for the models that associated the delta C-13 change to time, resulting in carbon half-life values of 23.33 days for T1 and 25.96 days for T2. Based on values found for the muscle delta C-13 change rate from growth (0.0263 day(-1) and 0.0254 day(-1)) and turnover (0.0034 day(-1) and 0.0013 day(-1)), our results indicate that most of the delta C-13 change could be attributed to growth. The application of model that associated the delta C-13 change to body mass increase seems to produce results with no apparent biological explanation. The delta C-13 change rate could directly reflect the daily ration and growth rate, and consequently the isotopic change rates of carbon and other tissue elements can be properly used to assess different factors that may interfere in nutrient utilization and growth. (c) 2006 Published by Elsevier B.V.

Polissemia nos usos do verbo ter: arbitrariedade ou iconicidade?

Pós-graduação em Estudos Linguísticos - IBILCE