Bézier曲线间最近距离的计算方法

针对Bzier曲线间最近距离计算问题,提出一种简捷、可靠的计算方法.该方法以Bernstein多项式算术运算为工具,建立Bzier曲线间最近距离的计算模型;然后充分利用Bzier曲面的凸包性质和de Casteljau分割算法进行求解.该方法几何意义明确,能有效地避免迭代初始值的选择和非线性方程组的求解,并可进一步推广应用于计算Bzier曲线/曲面间的最近距离.实验结果表明,该方法简捷、可靠且容易实现,与Newton-Raphson方法的融合可进一步提高该方法的运行速度.

模糊自适应PID在磁悬浮系统中的应用

针对EMS型磁悬浮列车悬浮系统的非线性、迟滞性及模型不确定的特点,本文采用了模糊自适应整定PID控制技术来满足其对动态和静态性能的要求。仿真结果表明模糊自适应整定PID控制器学习精度高、收敛速度快、在系统同时存在磁悬浮系统参数的变化和负载扰动时.具有较强的鲁棒性和抗干扰能力。

地质导向钻井关键技术及方法

On the basis of analyzing the principle and realization of geo-steering drilling system, the key technologies and methods in it are systematically studied in this paper. In order to recognize lithology, distinguish stratum and track reservoirs, the techniques of MWD and data process about natural gamma, resistivity, inductive density and porosity are researched. The methods for pre-processing and standardizing MWD data and for converting geological data in directional and horizontal drilling are discussed, consequently the methods of data conversion between MD and TVD and those of formation description and adjacent well contrast are proposed. Researching the method of identifying sub-layer yields the techniques of single well explanation, multi-well evaluation and oil reservoir description. Using the extremum and variance clustering analysis realizes logging phase analysis and stratum subdivision and explanation, which provides a theoretical method and lays a technical basis for tracing oil reservoirs and achieving geo-steering drilling. Researching the technique for exploring the reservoir top with a holdup section provides a planning method of wellpath control scheme to trace oil and gas reservoir dynamically, which solves the problem of how to control well trajectory on condition that the layer’s TVD is uncertain. The control scheme and planning method of well path for meeting the demands of target hitting, soft landing and continuous steering respectively provide the technological guarantee to land safely and drill successfully for horizontal, extended-reach and multi-target wells. The integrative design and control technologies are researched based on geology, reservoir and drilling considering reservoir disclosing ratio as a primary index, and the methods for planning and control optimum wellpath under multi-target restriction, thus which lets the target wellpath lie the favorite position in oil reservoir during the process of geo-steering drilling. The BHA (bottomhole assembly) mechanical model is discussed using the finite element method, and the BHA design methods are given on the basis of mechanical analyses according to the shape of well trajectory and the characteristics of BHA’s structure and deformation. The methods for predicting the deflection rate of bent housing motors and designing their assemblies are proposed based on the principle of minimum potential energy, which can clearly show the relation between the BHA’s structure parameters and deflection rate, especially the key factors’ effect to the deflection rate. Moreover, the interaction model between bit and formation is discussed through the process of equivalent formation and equivalent bit considering the formation anisotropy and bit anisotropy on the basis of analyzing the influence factors of well trajectory. Accordingly, the inherence relationship among well trajectory, formation, bit and drilling direction is revealed, which lays the theory basis and technique for predicting and controlling well trajectory.

三角洲储层孔隙结构模型与剩余油分布研究——以临南油田沙河街组储层为例

The study of pore structure in reservoir was paid attention to in the early reservoir research and now a systematic research methodology is set up. On the limits of tools and conditions, methodologies and technologies on formation condition and distribution laws of pore structure and the relationship between remaining oil distribution and pore structure are uncertain and some knownage about it is also uncertain. As the development of petroleum industry, the characterization of pore structure and the prediction of remaining oil are the hot spot and difficult point in the research of oil development. The author pays a close attention to this subject and has done much research on it. In a case study in Linnan oilfield Huimin sag Jiyang Depression Bohai Bay basin by using a new method, named varied scale comprehensive modeling of pore structure, the author builds pore structure models for delta reservoir, reveals the remaining oil distribution laws in delta facies, and predicts the distribution of remaining oil in Linnan oilfield. By the application of stratigraphy, sedimentology and structure geology. the author reveals the genetic types of sandbody and its distribution laws, builds the reservoir geological models for delta sandstone reservoir in Shahejie group in Linnan oilfield and points out the geological Factors that control the development of pores and throats. Combining petrology and the reservoir sensitive analysis, the author builds the rock matrix models. It is the first time to state that rocks in different sentimental micro facies have different sensitive .response to fluid pressed into the rocks. Normally. the reservoirs in the delta front have weaker sensitivity to fluid than the reservoirs in delta plain, In same subfacies, the microfacies that have fine grain, such as bank and crevasse splay, have stronger reservoir sensitivity than the microfacies that have coarse grains, such as under-water branched channel and debauch bar. By the application of advanced testing, such as imagine analysis, scan electronic microscope, and morphology method, the author classifies the pore structure and set up the distribution models of pore, throat and pore structure. By the application of advanced theory in well-logging geology, the author finds the relationship between microscope pore structure and macroscopic percolation characteristics, and then builds the well-logging interpretation formulae for calculating pore structure parameters. By using the geostatistics methods, the author reveals the spatial correlative characteristics of pore structure. By application of conditional stochastic simulation methods, the author builds the 3D models of pore structure in delta reservoir. It is the base of predicting remaining oil distribution. By a great deal of experiments and theoretical deduction, The author expounds the laws of percolation flow in different pore structures, and the laws by which the pore structure controls the micro distribution of remaining oil, and then, states the micro mechanism of remaining oil distribution. There are two types of remaining oil. They are by-pass flow caused by micro-fingering and truncation caused by non-piston movement. By new method, the author states the different pore structure has different replacement efficiency, reveals the formation condition and distribution laws of remaining oil. predicts the remaining oil distribution in Linnan oil field, and put forward some idea about how to adjust the oil production. The study yielded good results in the production in Linnan oilfield.

凝析油气藏描述及开发对策研究-以莫北2油气藏为例

Gas condensate reservoir research involves not only structure sediment reservoir liquid properties characterization but also the change of the temperature field, the change of the pressure field, the change of liquid phase and the reservoir sensitivity. To develop the gas condensate reservoir effectively .we must depict the static properties of the oil and gas system ,build exact and comprehensive parameter field, predict the rule of dynamic change and do the necessary reservoir characterization development plan dynamic prediction direct production. The MoBei Oil and Gas Field is the first gas condensate reservoirs which is found by the Xinjiang Oil Field Company in ZhunGaEr basin belly.it has deserved some knowledge after prospect evaluation, the MoBei Oil and Gas Field start development ,it is one of the important development blocks of Xinjiang Oil Field Company productivity constuction. During its development , it gradually appears some problems, such as complex oil and gas phase, great change of reservoir stretch .uncertain reservoir type and scale, controling its development strategy and plan difficultly. To deserve the high efficient development and long-term stable production of the gas condensate reservoir, it is necessary to characterize it systematically and form a suit of scientific development strategy. This thesis take the MoBei zone SanGongHe sand group reservoir as research object, applied advanced log techniques ,such as the nulear magnetism log ,MDT testing .etc. After comprehensive research of loging geology information, set up a suit of methods to identify oil gas water layer .these methods can identify the gas-oil level and the oil-water level. On the basis of reasonable development object system, according fine structure interpretation and structure modeling. build any oil water column height of the reservoir accurately. Through carefully analysis of the basic theory and method of reservoir seism prediction. optimize a reservoir inversion method .technique. software fitting the research region aiming strata, set up the GR field, porosity field, Rt field, impedence field .permeability field and initial oil saturation field, generating the base of quantity reservoir characterization. Discussing the characteristic of reservoir fluid and the movement and reallocating of muti-phase fluid in reservoir. And according the material of 100 soviet gas condensate reservoir ,build the recognition method and mode of gas condensate reservoir. Building the 3D geology model ,carry on the static and production evaluation, propose the development strategy and improve plan , provide the base of increasing reserves and advancing production and enriching the prospect development theory of the gas condensate reservoi

中-新元古代海洋的硫和碳同位素的演化

Data on seawater carbon isotope in the Mesoproterozoic and Neoproterozoic is abundant. However, the sulfur isotopic age curve of seawater sulfates determined through the analysis of sulfur isotopic composition of marine evaporite is uncertain in the Mesoproterozoic and Neoproterozoic since evaporites are generally rare in Precambrian. The Mesoproterozoic and Neoproterozoic Carbonate Formations preserve not only the carbon isotopic records, but also the sulfur isotopic records of coeval seawater in the Huabei Platform and the Yangtze Platform, China. Sulfur isotopic composition can be determined by the extraction of trace sulfate from carbonate samples. Successive measurements of sulfur and carbon isotopic compositions of carbonate samples from the Mesoproterozoic and Neoproterozoic strata in the Huabei Platform and the Yangtze Platform was accomplished through the extracting of trace sulfate from carbonates. Sulfur and carbon isotopic compositions of coeval seawater were obtained from analytical results of sulfur and carbon isotopes of the same sample without diagenetic alteration. The high-resolution age curve of sulfur isotope given in this paper may reflect the trend of variations in sulfur isotope composition of seawater sulfates during the Mesoproterozoic and Neoproterozoic. It can be correlated with the characteristics of variation in age curve of carbon isotope of coeval seawater carbonates. The δ34S values of seawater varied from +10.3-37.0‰ during the Mesoproterozoic, which took on oscillated variation on the whole. The δ34S values took on high values in the Mesoproterozoic Chuanlinggou stage, Tuanshanzi stage Tieling stage and in Neoproterozoic Jing'eryu stage. The average of those was about +30‰. The sulfates have low δ34S values in the Mesoproterozoic Yangzhuang stage and Hongshuizhuang stage, The average of those was all lower than +20‰. There occured large-amplitude changs in δ34S values of seawater during the Mesoproterozoic. Large-amplitude oscillate of 534S values occured in the intervals of 1600~1400Ma and 1300~1200Ma. The δ13C values of seawater are mostly negative in Changcheng stage of late Paleoproterozoic, -0 ± 1‰ range in Jixian stage of Mesoproterozoic , and the positive 2±2‰ commonly in early Neoproterozoic Jing'eryu stage. From 1000 Ma to 900 Ma, about 108 years interval of oceanic 513C record is shortage. At the end of Paleoproterozoic (1700 - 1600 Ma), the oceanic 813C values change from -3‰ to 0‰, but strongly oscillate near 1600 Ma. Two larger variations of seawater 513C values occur in the Mesoproterozoic: one is a cycle of about 4%o happens at ca. 1400 Ma; another is rise from >2‰ to>5‰ at ca. 1250 Ma and then become stable at the near 1000 Ma. There appears a large positive excursion over +20‰ in 534S value of ancient seawater sulfates in the early Doushantuo stage. Simultaneously, 8 C values of ancient seawater occur a positive excursion reaching 10‰. These allow δ4S values and 513C values to reach high values of+51.7‰ and +6.9‰, respectively. The range of variation in 834S values of seawater is relatively narrow and 513C values are quite high in the middle Doushantuo stage. Then, δ34S values of seawater become oscillating, the same happens in δ13C values. Negative excursions in 834S values and 813C values occur simultaneously at the end of the Doushantuo stage, and the minimum of δ34S values and δ13C values dropped to -11.3‰ and -5.7‰, respectively. The ancient seawater in the Dengying stage has high δS values and δ13C values. Most of the δ34S values of the trace sulfate samples varied between +23.6‰ and +37.9‰ except two boundaries of the Dengying Formation, and the S13C values of the carbonate samples of the Dengying Formation varied between +0.5‰ and +5.0‰. There appeared large negative excursion in 834S values and δ13C values of ancient seawater at the bounder of Precambrian-Cambrian. The isotopic characteristics of sulfur and carbon implicated that the organic productivity and isotopic fractionation caused by biology were low and the palaeoceanic environment was quite unstable during the Mesoproterozoic. The increase and subsequent oscillation of seawater δ13C value occurred from 1700 to 1600 Ma and near 1300 Ma may be responsible to the two global tectonic events happened at coeval time. The characteristics of variation in sulfur and carbon isotopes of ancient seawater imply strong changes in oceanic environment, which became beneficial to inhabitation and propagation of organism. The organic production and the burial rate of organic carbon once reached a quite high level during the Doushantuo stage. However, the state of environment became unstable that means the global climate and the environment possibly were fluctuating and reiterating after the global glaciation. The negative excursions of S34S values and δ13C values occurring at the end of the Doushantuo stage represent a global event, which might be relative to the oxidation of deep seawater. The isotopic characteristics of sulfur and carbon implicated that there were a high organic productivity and a high burial rate of organic carbon in the Dengying stage. It is obvious that the palaeoceanic environment in Dengying stage was stable corresponding and beneficial for biology to inhabit and propagate except for the two boundaries. The tendency of sulfur and carbon isotopic variations maybe resulted from the gradual oxygenation of ocean environment during the Dengying stage. It has been reported that the secular variations of the sulfur isotopic compositions in seawater was negative correlated with that of carbon isotopic compositions. However, our results show that it is not the case. They were negatively correlated in some intervals and positively in some other intervals of the Mesoproterozoic and Neoproterozoic. The difference in correlation may be associated with the changes in conditions of redox in oceanic environment, e.g. sharp change of the oxidation-reduction interface. The strong changes in global environment may induce the abnormality to occur in the biogeo chemical S and C cycles in the ocean and accordingly sharp Variations in isotopic composition of seawater sulfur and carbon during the Mesoproterozoic and Neoproterozoic. Simultaneously, the global tectonism caused large changes of 87Sr/86Sr ratios. The leading factor that causes the variation in isotopic composition is different in the different intervals of the Mesoproterozoic and Neoproterozoic. Thus, there may exist different models of the biogeochemical S and C cycles in the ocean during the Mesoproterozoic and Neoproterozoic.

滚石机理及滚石灾害评价研究

Rockfall is a geological evolution process involving detachment of blocks or boulders from a slope face, then their free falls, bouncing, rolling or sliding, and finally deposition near the toe of the slope. Many facts indicate that the rockfall can cause hazards to peoples, and it can be regarded as a geological hazard. A rockfall event may only involve a boulder or rock, and also several ones. When there are peoples, buildings, or other man-made establishments within the scope of rockfall trajectory, losses will be possibly induced in tenns of human lives or damages to these facilities. Researches into mechanism, kinematics, dynamics, hazard assessment, risk analysis, and mitigation measures of rockfalls are extremely necessary and important. Occurrence of rockfall is controlled by a lot of conditions, mainly including topographical, geomorphic, geological ones and triggering factors. The rockfall especially in mountainous areas, has different origins, and occurs to be frequent, unexpected, uncertain, in groups, periodic and sectional. The characterization and classification of the rockfalls not only increase knowledge about rockfall mechanism, but also can instruct mitigation of the hazards. In addition, stability of potential rockfalls have various sensitivity to different triggering factors and changes of geometrical conditions. Through theoretical analyses, laboratory experiments and field tests, the author presents some back-analysis methods for friction coefficients of sliding and rolling, and restitution coefficients. The used input data can be obtained economically and accurately in the field. Through deep studies on hazard assessment methods and analysis of factors influencing rockfall hazard, this paper presents a new assessment methodology consisting of preliminary assessment and detailed one. From the application in a 430 km long stretch of the Highway, which is located between Paksho and Nyingtri in Tibet, the methodology can be applicable for the rockfall hazard assessment in complex and difficult terrains. In addition, risk analyses along the stretch are conducted by computing the probability of encountering rockfalls and life losses resulting from rockfall impacts. Rockfall hazards may be mitigated by avoiding hazardous areas, clearness of dangerous rocks, reinforcement, obstructing the rockfalls, leading the rockfalls, warning and monitoring for rockfalls, etc. Seen from present remedial level of rockfall hazards, different mitigation measures, economical and effective buffering units, monitoring tecliniques and consciousness of environmental protection for rockfall mitigations should be further developed.

运动距离效应的认知编码机制

Among the cognitive studies of action, an important behavioral method is used to observe Reaction Time (RT) and Movement Time (MT) as the functions of motor parameters. RT is measured from the beginning of target presentation to the initiation of a movement, which is regarded as the programming of the ongoing movement. MT is measured from the initiation to the end of the movement, which is regarded as the execution of the movement. However, the relationship between RT and motor parameters remains uncertain till now. Under the uncertainty many related issues cannot be settled for long period, especially the issues as whether the amplitude effect appears during RT, or what should the amplitude effect be during RT. The present study aimed to find out the amplitude effect and the related cognitive process under different experimental conditions. First, we discussed the potential composition of RT and suggested that RT that normally measured in previous experiments might not reflect motor programming very well. Then we designed a series experiments to observe the relationship between RT and motor programming by using different Index of Difficulty (ID), different instructions in which speed and accuracy were emphasized respectively, different vision condition during movement execution and Go/NoGo paradigm. Meanwhile, we compared the amplitude effect under the respective RT to make the specific conclusion about the amplitude effect, and the relationship between RT and MT as well. The main findings are showed as following. 1) Because of the existing of “preview”, “visual feedback control” and “speed-accuracy tradeoff”, RT reflects motor programming differently under different experimental conditions. 2) Under different experimental conditions, the amplitude effect on RT varies. RT could be too short to exhibit the amplitude effect. Or the amplitude effect could be that more RT is needed for shorter movement when RT is prolonged. Or the amplitude effect could be that more RT is needed for longer movement when RT is further prolonged. 3) Under the present experimental conditions, the amplitude effect on MT showed consistently that longer movement needs longer MT. 4) Under the present experimental conditions, the relationship between RT and MT is a kind of compensation. The present study has important theoretic significance. The cognitive process of action is an important part of human cognitive behavior. The related studies could be very helpful for human people to know about themselves and the relation between themselves and the surroundings as well. Keywords motor programming; amplitude effect; Reaction Time (RT); Movement Time (MT)

5-9岁儿童对常见病病因及其致病不确定性的认知发展

Research on children's naive concepts has previously tended to focus on the domains of physics and psychology, but more recently attention has turned to conceptual development in biology as a core domain of knowledge. Because of its familiarity, illness has been a popular topic for researchers in this domain. However, they have only studied the children’s understanding of its causes. Other aspects of illness, such as treatment and prognosis, have received little attention. This research addresses the development of 5- to 9-year-old children’s understanding of the causes of illness and their probabilities via open-ended and forced choice interviews. The results of this research are: 1) Most of the 5- to 7-year-old children used behavioral causes to explain illness, and the 9-year-old children primarily used biological causes to interpret illness. With age, more and more children selected psychological causes to explain illness. 2) Pre-school children did not over-generalize contagions to non-contagious illnesses. They used behavioral and biological causes to explain contagious illnesses. For non-contagious illnesses, they chose only behavioral causes. 3) Most of the children used only one kind of cause to explain illness. 4) Some preschool-aged children viewed outcomes of familiar causes of illness as probabilistic. With age, more and more could make uncertain predictions of illness. 5) The children’s understanding of the causes’ probabilities appeared to be based on naïve biology. 5- to 9-year-old children often made probabilistic predictions by analyzing a single cause of illness. 6) Children coming from higher educational backgrounds outperformed their counterparts coming from lower educational backgrounds with respect to understanding illness. 7) Specific knowledge acquired could generally improved the preschoolers’ understanding of causes of illness and their probabilities.

不确定性类型对概率表达和概率判断的影响

The present research firstly reviewed the experimental literature on probability expression and probability judgment, hypothesizing that individuals’ preference of probability expressions (verbal probability vs. numerical probability) and tendency for overextremity in probability judgment might differ with respect to different types of uncertainty. Five studies were conducted to test this hypothesis. In Study 1, questionnaires were used to explore the communication preference among Chinese-speaking people. Study 2 adapted the View of Uncertainty Questionnaire to explore the difference of verbal answers to three kinds of uncertainty. Study 3 and Study 4 used methods of the paper-and-pencil questionnaire and the laboratory experiment, respectively, to test the effects of uncertainty types on the preference of probability expressions and on the tendency for over-extreme probability judgment. Finally, Study 5 focused on individuals’ preference of probability expressions under various kinds of scenarios. The results were as follows: 1. The Communication Model Preference paradox phenomenon appears to be even more pronounced in the Chinese culture than in American English cultural settings. 2. The Chinese prefer more verbal probability expressions when communicating uncertainty in a weather-forecasting context than in a general context. 3. Sample groups with lower level of westernization tend to give more extreme answers and less probabilistic answers. 4. Types of uncertainty did have effects on individuals’ tendency for over-extreme probability judgment: under a traditional probability judgment task, people tend to be more over-extreme on internal uncertainty events than on external uncertainty events; however, this result is reversed under a gambling task. 5. Individuals’ preference for verbal probability expressions is more salient on internal uncertain events than on external uncertain events.

服务质量要素体系的探讨

The study explored consumers' evaluation factor system and the zone of tolerance in the service quality, and the impact on consumer behavior in two branches of trade: the shopping center and the architectural material corporation, with the method of questionnaire survey. The main conclusions are as following: 1) The basic factors on service quality of shopping center are five, such as assurance、tangibles、the services of the post-selling、convenience and reliability. 2) There are also five factors on service quality of the architectural material corporation, such as the supplying of the products, the abilities of the salesmen, courtesy, package and the information. 3) The zones of tolerance of the factors in service quality are difference. In some way, they reflect the importance of the factors. 4) the service quality and its factors have positive impacts on the consumer behaviors. 5) In the branch of glass producing in our country, the service quality of a corporation is significant below the ideal level, even if it is a good one which the consumers expressed positive purchase intention on the corporate. The service quality of the coporate on which the consumers expressed uncertain purchase intention, is in nearby of the minimum acceptable level.

Purification of human tissue prokallikrein excreted from insect cells by liquid chromatography

Tissue kallikrein, generally existing in living bodies as prokallikrein, is a serine proteinase that has proven of great significance to treat hypertension, cardiopathy and nephropathy. Although the extraction of tissue kallikrein from human urine is the most commonly used method to obtain such a protein, not only the yield is very little, but also the procedure is rather complex. Furthermore, the biological safety is uncertain. Therefore, the preparation of such a protein by genetic engineering method, including gene expression, cell culture, separation and purification, is very important. In this paper, a new method to obtain purified tissue prokallikrein excreted from insect cells by liquid chromatography has been proposed. In contrast to the previously published papers, the purification procedure is simplified to only three steps with the final yield of 57% and the purity of 95%, which is not only convenient, but also low-cost and suitable for the large-scale preparation of such a protein. The purified protein is further validated as prokallikrein by high performance liquid chromatography-mass spectrometry and amino acid sequencing. (c) 2005 Elsevier B.V. All rights reserved.

Water-based exercise for adults with asthma

BackgroundAsthma is a common condition characterised by airway inflammation and airway narrowing, which can result in intermittent symptoms of wheezing, coughing and chest tightness, possibly limiting activities of daily life. Water-based exercise is believed to offer benefits for people with asthma through pollen-free air, humidity and effects of exercise on physical function.ObjectivesTo evaluate the effectiveness and safety of water-based exercise for adults with asthma.Search methodsWe searched the Cochrane Airways Group Specialised Register of Trials (CAGR), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Allied and Complementary Medicine Database (AMED), PsycINFO, the Latin American and Caribbean Health Science Information Database (LILACS), the Physiotherapy Evidence Database (PEDro), the System for Information on Grey Literature in Europe (SIGLE) and Google Scholar on 13 May 2014. We handsearched ongoing clinical trial registers and meeting abstracts of the American Thoracic Society (ATS), the European Respiratory Society (ERS) and the British Thoracic Society (BTS).Selection criteriaWe included all randomised controlled trials (RCTs) of adults with asthma comparing a water-based exercise group versus one or more of the following groups: usual care, land-based exercise, non-exercise.Data collection and analysisTwo review authors (AJG, VS) independently extracted data fromthe primary studies using a standard form developed for this purpose, which includes methods, participants, interventions and outcomes. We contacted trial authors to request additional data. Data were input by one review author and were double-checked by a second review author.Main resultsIn this systematic review, we provide a narrative synthesis of available evidence from three small studies including 136 adult participants. the studies were at high risk of bias. No meta-analysis was possible because of methodological and interventional heterogeneity between included studies. the primary outcomes of quality of life and exacerbations leading to use of steroids were not reported by these studies. for exacerbations leading to health centre/hospital visits, uncertainty was wide because a very small number of events was reported (in a single study). Secondary outcomes symptoms, lung function, changes in medication and adverse effects, where available, described for each included study. the overall quality of the studies was very low, and no clear differences were noted between water-based exercise and comparator treatments. Therefore, we remain very uncertain about the effects of water-based exercise for adults with asthma.Authors' conclusionsThe small number of participants in the three included studies, the clinical and methodological heterogeneity observed and the high risk of bias assessed mean that we are unable to assess the place of water-based exercise in asthma. Randomised controlled trials are needed to assess the efficacy and safety of water-based exercise for adults with asthma. for future research, we suggest greater methodological rigour (participant selection, blinding of outcome assessors, reporting of all outcomes analysed and registering of the study protocol).

Effectiveness and safety of cryotherapy after arthroscopic anterior cruciate ligament reconstruction. A systematic review of the literature

Cryotherapy is widely used in rehabilitation; however, its effectiveness after anterior cruciate ligament (ACL) reconstruction remains uncertain. To investigate the effectiveness and safety of cryotherapy following ACL reconstruction through a systematic review, randomized and quasi-randomized clinical trials were searched in the databases: MEDLINE, EMBASE, CENTRAL PEDro, SportDiscus, CINAHL, LILACS (June 2013). the primary outcomes measures were pain, edema and adverse events; the secondary outcomes were knee function, analgesic medication use, range of motion, blood loss, hospital stay, quality of life and patient satisfaction. the methodological quality of studies was evaluated using the Cochrane Collaboration risk-of-bias tool. Ten trials (a total of 573 patients) were included. Results of meta-analysis showed that the use of cold compression devices produced a significant reduction in pain scores 48 h after surgery (p < 0.00001), compared to no cryotherapy. the risk for adverse events did not differ between patients receiving cryotherapy versus no treatment (p = 1.00). the limited evidence currently available is insufficient to draw definitive conclusions on the effectiveness of cryotherapy for other outcomes. There is a need for well designed, good quality randomized trials to answer other questions related to this intervention and increase the precision of future systematic reviews. (C) 2014 Elsevier B.V. All rights reserved.

Moving to manage: A mixed methods study of later life relocation into supported housing.

This study describes relocation experiences of older people moving to supported housing in Scotland focusing on the nature of support. Using mixed methods, Phase one involved a Scottish cross-sectional survey of all people aged 65 and over moving into Coburg (Scotland) Housing Association supported accommodation during the first six months of 2008. A total of 122 respondents were included in the survey (59% response rate). People moved locally at advanced ages with moderate disability levels to achieve more manageable housing and support, suggesting ‘assistance migration’. Expectations were high, with many seeing it as a new start in life and generally positive views of moving were reported. In Phase two, five in-depth multiple-perspective longitudinal case studies were conducted to explore the experience of relocation into supported housing. In each case an older person, primary carer and the housing manager - all women – were interviewed over six months following relocation. Analysis was undertaken using a thematic framework approach (Ritchie et al., 2003). Findings suggested older women acted with agency to adapt to their new lives; recreating ‘normality’ through organising space and routines. It is argued that returning to normality formed the overarching objective of the older women as they sought to feel ‘in place’. Responsibilities for meeting assistance needs were often implicit, contested and shifting, leading to fragile, uncertain and transitory arrangements. Drawing on recent advances in developmental psychology it is argued ‘longings’ of older people, and others, to achieve an optimal life can relate and motivate towards actions such as relocation. Yet, personal ‘longings’ can be prioritised differently and may result in disputes over goal setting and ways needs are met. Further, utopian ideals must be reconciled with the reality of daily life. Policy and practitioners could adopt broader, dignity based objectives to assist older people to identify ways of aiding such reconciliation.