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Practical Point (practical + point)
Selected AbstractsWould you like to shrink the welfare state?ECONOMIC POLICY, Issue 32 2001A survey of European citizens The fundamental problems facing European welfare states , high unemployment and unsustainable public pensions plans in particular , have been in the political debate for years, so why have we seen so little reform? To find out, we surveyed the opinions of citizens in France, Germany, Italy and Spain on their welfare states and on various reform options. This is what we found. First, most workers underestimate the costs of public pensions, though they are aware of their unsustainability. Second, the status quo is a majoritarian outcome: a majority of citizens opposes cuts to social security and welfare spending, but also opposes further increases. Since population ageing without reform implies an automatic expansion, our results suggest that most citizens would favour reforms that stabilize but do not shrink the current welfare states. Third, many would welcome changes in the allocation of benefits. A large number of workers in Italy and Germany would be willing to opt out of public pensions and replace them with private pensions, though the details of how this scheme is formulated matter for its popularity. And many Italians and Spaniards would welcome an extension of the coverage of unemployment insurance. Fourth, conflicts over the welfare state are mainly shaped by the economic situation of the respondent, while political ideology plays a limited role. Disagreements are found along three dimensions: young versus old, rich versus poor, and ,outsider' versus ,insider' in terms of labour market status. From a practical point of view, this suggests that there is scope to bundle reforms strategically in order to build a large and mixed coalition of supporters. , Tito Boeri, Axel Börsch-Supan and Guido Tabellini [source] Fast immobilization of probe beads by dielectrophoresis-controlled adhesion in a versatile microfluidic platform for affinity assayELECTROPHORESIS, Issue 19 2005Janko Auerswald Dr. Abstract The use of probe beads for lab-on-chip affinity assays is very interesting from a practical point of view. It is easier to handle and trap beads than molecules in microfluidic systems. We present a method for the immobilization of probe beads at defined areas on a chip using dielectrophoresis (DEP)-controlled adhesion. The method is fast, i.e., it takes between 10 and 120,s , depending on the protocol , to functionalize a chip surface at defined areas. The method is versatile, i.e., it works for beads with different types of probe molecule coatings. The immobilization is irreversible, i.e., the retained beads are able to withstand high flow velocities in a flow-through device even after the DEP voltage is turned off, thus allowing the use of conventional high-conductivity analyte buffers in the following assay procedure. We demonstrate the on-chip immobilization of fluorescent beads coated with biotin, protein,A, and goat,antimouse immunoglobulin G (IgG). The number of immobilized beads at an electrode array can be determined from their fluorescence signal. Further, we use this method to demonstrate the detection of streptavidin and mouse IgG. Finally, we demonstrate the feasibility of the parallel detection of different analyte molecules on the same chip. [source] Trace Metals in Anaerobic Granular Sludge Reactors: Bioavailability and Dosing StrategiesENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 3 2006H. Zandvoort Abstract The trace metal dynamics in anaerobic granular sludge bed reactors and their influence on reactor performance is reviewed in this paper. An insight into the metal dynamics is required from a practical point of view in order to be able to early recognize limitations for essential trace elements, viz., to know when dosing of these elements is required in full-scale anaerobic bioreactor applications. Further such knowledge is indispensable for a rational dosage of these metals, e.g., to ensure maximum substrate conversion rates and to prevent disturbances in reactor performance using a minimum amount of metals. Therefore, the retention, accumulation and release of trace metals in anaerobic granular sludge and the factors affecting these processes need to be known. [source] Metastable zone determination of lipid systems: Ultrasound velocity versus optical back-reflectance measurementsEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 5 2010Kesarin Chaleepa Abstract The metastable zone width (MZW) of a multi-component system as influenced by the process parameters cooling rate, agitation speed, and additive concentration was determined via ultrasound velocity measurements. The results were compared with those obtained by optical back-reflectance measurements (ORM) using coconut oil as a model substance. Increasing the cooling rate led to the shift of the nucleation point to lower temperatures. This tendency was better visualized by the ultrasonic curves while a significant disturbance of the ORM signal could be observed. Agitation led to an increase of the nucleation temperature and hence a narrower metastable zone. The influence of an additive on the MZW was found to strongly depend on its concentration. The MZW detected by the ultrasound technique was narrower compared to that obtained by the ORM method, indicating the faster response to the phase transition of the ultrasound technique. Another advantage of the ultrasound technique was the in situ evaluation of the experimental data, while ORM needed a linear fitting to estimate the saturation temperature. Furthermore, ultrasound velocity measurements are based on density determination of the medium whereas the ORM sensor is able to detect only particles that are located within the measuring zone and possess a well-defined size. Practical applications: MZW is one of the most important parameters that determine the characteristics of crystalline products. However, a proper technique that can be used in MZW detection in fat systems has rarely been reported, due to the difficulties in dealing with natural fats. The findings of this study can greatly help those who are involved in the field of fat crystallization from both the academic and the practical point of view. This is due to the fact that new and promising techniques for the online and in situ determination of the MZW of fats, with high accuracy, and reproducibility, under most process conditions, were clarified in this work. The readers can easily follow the procedure developed in this paper. Also information about the influence of process parameters and additives on the MZW is included. [source] Distortions of EM transients in coincident loops at short time-delaysGEOPHYSICAL PROSPECTING, Issue 6 2000F. Kamenetsky Transient electromagnetic measurements with short time-delays of transients are used for solving different problems within the upper part of a geoelectric section. However, it is necessary to take into consideration distortions connected with self-transients within the transmitter,receiver system. From the practical point of view, it is important to estimate the minimum time-delay after which these distortions may be neglected. We present such an estimation which uses a simple approximation method for a single-loop (or coincident-loop) configuration. For common values of the loop size (10 m × 10 m to 40 m × 40 m) and of the resistivity of a homogeneous half-space (1,100 ,m), the minimum time-delay beyond which we can use a standard interpretation is in the range of 2,10 µs. This is equivalent to a minimum depth of investigation in the range of 1,30 m. [source] HDL-c is a powerful lipid predictor of cardiovascular diseasesINTERNATIONAL JOURNAL OF CLINICAL PRACTICE, Issue 11 2007E. Bruckert Summary Relationship between HDL-c and cardiovascular diseases:, Beyond the role of low-density lipoprotein cholesterol (LDL-c) in the development of atherosclerosis, growing evidence suggest that high-density lipoprotein cholesterol (HDL-c) is a powerful predictor of cardiovascular disease. Indeed, epidemiological, mechanistic and intervention studies suggest that low HDL-c is a major cardiovascular risk factor and that increasing HDL-c plasma levels may be beneficial, particularly in patients with low HDL-c levels. The inverse association between HDL-c concentrations and cardiovascular risk is continuous without threshold value. Thus, any categorical definition of low HDL-c is arbitrary. Protective effects of HDL:, HDL particles are highly heterogeneous in structure and intravascular metabolism. Antiatherogenic properties of HDL include its role in the reverse cholesterol transfer, besides its antioxidant, anti-inflammatory and antiapoptotic activities. What should clinicians do?:, From a practical point of view, HDL-c should be systematically measured to assess the cardiovascular risk in patients. The first step to consider in subjects with low HDL-c is to look for specific causes and give advice to change inappropriate lifestyle components associated with low HDL-c, such as smoking, lack of physical exercise and overweight. Patients with very low HDL-c need a thorough evaluation by specialist physicians. Statins are associated with a modest increase of HDL-c (5%) while fibrates and nicotinic acid increase HDL-c by 10% and 20% respectively. [source] Imidazol(in)ium-2-carboxylates as N-Heterocyclic Carbene Precursors for the Synthesis of Second Generation Ruthenium Metathesis CatalystsADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2009Xavier Sauvage Abstract Five well-known ruthenium-N-heterocyclic carbene (NHC) catalysts for olefin metathesis and related reactions, including the second generation Grubbs and Hoveyda,Grubbs catalysts, were prepared by phosphane exchange between first generation ruthenium-benzylidene or indenylidene complexes and NHCs generated in situ upon thermolysis of imidazol(in)ium-2-carboxylates. Because N-heterocyclic carbene carbon dioxide adducts (NHC,CO2) are stable zwitterionic compounds that can be stored and handled with no particular precautions, this procedure is particularly attractive from a practical point of view. Reaction courses were conveniently monitored by 31P,NMR spectroscopy and the experimental conditions were carefully adjusted to obtain high yields of pure products within short periods of time. [source] An outlier robust GARCH model and forecasting volatility of exchange rate returnsJOURNAL OF FORECASTING, Issue 5 2002Beum-Jo Park Abstract Since volatility is perceived as an explicit measure of risk, financial economists have long been concerned with accurate measures and forecasts of future volatility and, undoubtedly, the Generalized Autoregressive Conditional Heteroscedasticity (GARCH) model has been widely used for doing so. It appears, however, from some empirical studies that the GARCH model tends to provide poor volatility forecasts in the presence of additive outliers. To overcome the forecasting limitation, this paper proposes a robust GARCH model (RGARCH) using least absolute deviation estimation and introduces a valuable estimation method from a practical point of view. Extensive Monte Carlo experiments substantiate our conjectures. As the magnitude of the outliers increases, the one-step-ahead forecasting performance of the RGARCH model has a more significant improvement in two forecast evaluation criteria over both the standard GARCH and random walk models. Strong evidence in favour of the RGARCH model over other competitive models is based on empirical application. By using a sample of two daily exchange rate series, we find that the out-of-sample volatility forecasts of the RGARCH model are apparently superior to those of other competitive models. Copyright © 2002 John Wiley & Sons, Ltd. [source] A self-normalized approach to confidence interval construction in time seriesJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES B (STATISTICAL METHODOLOGY), Issue 3 2010Xiaofeng Shao Summary., We propose a new method to construct confidence intervals for quantities that are associated with a stationary time series, which avoids direct estimation of the asymptotic variances. Unlike the existing tuning-parameter-dependent approaches, our method has the attractive convenience of being free of any user-chosen number or smoothing parameter. The interval is constructed on the basis of an asymptotically distribution-free self-normalized statistic, in which the normalizing matrix is computed by using recursive estimates. Under mild conditions, we establish the theoretical validity of our method for a broad class of statistics that are functionals of the empirical distribution of fixed or growing dimension. From a practical point of view, our method is conceptually simple, easy to implement and can be readily used by the practitioner. Monte Carlo simulations are conducted to compare the finite sample performance of the new method with those delivered by the normal approximation and the block bootstrap approach. [source] Do prior knowledge, personality and visual perceptual ability predict student performance in microscopic pathology?MEDICAL EDUCATION, Issue 6 2010Laura Helle Medical Education 2010:44:621,629 Objectives, There has been long-standing controversy regarding aptitude testing and selection for medical education. Visual perception is considered particularly important for detecting signs of disease as part of diagnostic procedures in, for example, microscopic pathology, radiology and dermatology and as a component of perceptual motor skills in medical procedures such as surgery. In 1968 the Perceptual Ability Test (PAT) was introduced in dental education. The aim of the present pilot study was to explore possible predictors of performance in diagnostic classification based on microscopic observation in the context of an undergraduate pathology course. Methods, A pre- and post-test of diagnostic classification performance, test of visual perceptual skill (Test of Visual Perceptual Skills, 3rd edition [TVPS-3]) and a self-report instrument of personality (Big Five Personality Inventory) were administered. In addition, data on academic performance (performance in histology and cell biology, a compulsory course taken the previous year, in addition to performance on the microscopy examination and final examination) were collected. Results, The results indicated that one personality factor (Conscientiousness) and one element of visual perceptual ability (spatial relationship awareness) predicted performance on the pre-test. The only factor to predict performance on the post-test was performance on the pre-test. Similarly, the microscopy examination score was predicted by the pre-test score, in addition to the histology and cell biology grade. The course examination score was predicted by two personality factors (Conscientiousness and lack of Openness) and the histology and cell biology grade. Conclusions, Visual spatial ability may be related to performance in the initial phase of training in microscopic pathology. However, from a practical point of view, medical students are able to learn basic microscopic pathology using worked-out examples, independently of measures of personality or visual perceptual ability. This finding should reassure students about their abilities to improve with training independently of their scores on tests on basic abilities and personality. [source] Standardized protocol for a depletion of intramyocellular lipids (IMCL)NMR IN BIOMEDICINE, Issue 5 2010Michael Ith Abstract Intramyocellular lipids (IMCL) are flexible fuel stores that are depleted by physical exercise and replenished by fat intake. IMCL or their degradation products are thought to interfere with insulin signaling thereby contributing to insulin resistance. From a practical point of view it is desirable to deplete IMCL prior to replenishing them. So far, it is not clear for how long and at which intensity subjects have to exercise in order to deplete IMCL. We therefore aimed at developing a standardized exercise protocol that is applicable to subjects over a broad range of exercise capacity and insulin sensitivity and allows measuring reliably reduced IMCL levels. Twelve male subjects, including four diabetes type 2 patients, with wide ranges of exercise capacity (VO2peak per total body weight 27.9,55.8,ml*kg,1*min,1), insulin sensitivity (glucose infusion rate per lean body mass 4.7,15.3,mg*min,1*kg,1), and BMI (21.7,31.5,kg*m,2), respectively, were enrolled. Using 1H magnetic resonance spectroscopy (1H-MRS), IMCL was measured in m.tibialis anterior and m.vastus intermedius before and during a depletion protocol of a week, consisting of a moderate additional physical activity (1,h daily at 60% VO2peak) and modest low-fat (10,15%) diet. Absolute IMCL-levels were significantly reduced in both muscles during the first 3 days and stayed constant for the next 3 days of an identical diet/exercise-scheme. These reduced IMCL levels were independent of insulin sensitivity, yet a tendency to lower depleted IMCL levels has been observed in subjects with higher VO2peak. The proposed protocol is feasible in subjects with large differences in exercise capacity, insulin sensitivity, and BMI, leading to reduced IMCL levels that neither depend on the exact duration of the depletion protocol nor on insulin sensitivity. This allows for a standardized preparation of IMCL levels either for correlation with other physiological parameters or for replenishment studies. Copyright © 2010 John Wiley & Sons, Ltd. [source] On the multilevel preconditioning of Crouzeix,Raviart elliptic problemsNUMERICAL LINEAR ALGEBRA WITH APPLICATIONS, Issue 5 2008J. Kraus Abstract We consider robust hierarchical splittings of finite element spaces related to non-conforming discretizations using Crouzeix,Raviart type elements. As is well known, this is the key to the construction of efficient two- and multilevel preconditioners. The main contribution of this paper is a theoretical and an experimental comparison of three such splittings. Our starting point is the standard method based on differences and aggregates (DA) as introduced in Blaheta et al. (Numer. Linear Algebra Appl. 2004; 11:309,326). On this basis we propose a more general (GDA) splitting, which can be viewed as the solution of a constraint optimization problem (based on certain symmetry assumptions). We further consider the locally optimal (ODA) splitting, which is shown to be equivalent to the first reduce (FR) method from Blaheta et al. (Numer. Linear Algebra Appl. 2004; 11:309,326). This means that both, the ODA and the FR splitting, generate the same subspaces, and thus the local constant in the strengthened Cauchy,Bunyakowski,Schwarz inequality is minimal for the FR (respectively ODA) splitting. Moreover, since the DA splitting corresponds to a particular choice in the parameter space of the GDA splitting, which itself is an element in the set of all splittings for which the ODA (or equivalently FR) splitting yields the optimum, we conclude that the chain of inequalities ,,,,,,3/4 holds independently of mesh and/or coefficient anisotropy. Apart from the theoretical considerations, the presented numerical results provide a basis for a comparison of these three approaches from a practical point of view. Copyright © 2007 John Wiley & Sons, Ltd. [source] Combination of Jacobi,Davidson and conjugate gradients for the partial symmetric eigenproblemNUMERICAL LINEAR ALGEBRA WITH APPLICATIONS, Issue 1 2002Y. Notay Abstract To compute the smallest eigenvalues and associated eigenvectors of a real symmetric matrix, we consider the Jacobi,Davidson method with inner preconditioned conjugate gradient iterations for the arising linear systems. We show that the coefficient matrix of these systems is indeed positive definite with the smallest eigenvalue bounded away from zero. We also establish a relation between the residual norm reduction in these inner linear systems and the convergence of the outer process towards the desired eigenpair. From a theoretical point of view, this allows to prove the optimality of the method, in the sense that solving the eigenproblem implies only a moderate overhead compared with solving a linear system. From a practical point of view, this allows to set up a stopping strategy for the inner iterations that minimizes this overhead by exiting precisely at the moment where further progress would be useless with respect to the convergence of the outer process. These results are numerically illustrated on some model example. Direct comparison with some other eigensolvers is also provided. Copyright © 2001 John Wiley & Sons, Ltd. [source] X-ray-induced debromination of nucleic acids at the Br,K absorption edge and implications for MAD phasingACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2002E. Ennifar Multi-wavelength anomalous dispersion (MAD) using brominated derivatives is considered a common and convenient technique for solving chemically synthesized nucleic acid structures. Here, it is shown that a relatively moderate X-ray dose (of the order of 5 × 1015,photons,mm,2) can induce sufficient debromination to prevent structure determination. The decrease in bromine occupancy with radiation dose can be accounted for by a simple exponential, with an estimated rate constant at the absorption-peak wavelength, 7.4,(0.8),MGy, that is not significantly different from its value at the absorption-edge wavelength, 9.2,(2.6),MGy (the given e.s.d.s assess the relative closeness of the two values, not their absolute accuracy, which is probably worse). Chemically, these results (and others) are consistent with bromine cleavage resulting from direct photodissociation and/or from the action of free electrons, rather than from the action of hydroxyl radicals originating from water dissociation. The free bromine species (Br,) diffuse too quickly, even in amorphous ice around 100,K, to allow the determination of a diffusion coefficient. From a practical point of view, it is suggested that a single data collection with a crystal consisting of iodinated instead of brominated derivatives could provide both anomalous scattering and SIR phase information by the progressive cleavage of iodine. [source] Seasonal dynamics, dispersion, sequential sampling plans and treatment thresholds for the citrus leafminer, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), in a mature lemon block in coastal New South Wales, AustraliaAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 3 2008Zhong Min Liu Abstract, Studies of citrus leafminer in a coastal orchard in NSW, Australia indicated that an increase in abundance to about one mine per flush was followed during the midseason flush by a rapid increase in population that was related to an increase in the percentage of leaves infested within flushes and the number of mines per leaf. The fits of frequency distributions and Iwao's patchiness regression indicated that populations were highly contagious initially, and as the exponent k of the negative binomial distribution increased with increasing population density, the distribution approached random. Concurrently, the coefficient of variation of mines per flush (which was strongly related to the proportion of un-infested flushes) decreased to about unity as the proportion of un-infested flushes reached zero and fell further as the number of mines per flush increased. Both numerative and binomial sequential sampling plans were developed using a decision threshold based on 1.2 mines per flush. The binomial sampling plan was based on a closely fitting model of the functional relationship between mean density and proportion of infested flushes. Functional relationships using the parameters determined from Iwao's patchiness regression and Taylor's power law were equally satisfactory, and one based on the negative binomial model also fitted well, but the Poisson model did not. The three best fitting models indicated that a decision threshold of 1.2 mines per flush was equivalent to 50% of flushes infested. From a practical point of view, the transition from 25% infestation of flushes through 50% is so rapid that it may be prudent to take action when the 25% level is reached; otherwise, the 50% may be passed before the crop is checked again. For valuable nursery stock should infestation be detected in spring, it may be advisable to apply prophylactic treatment as the midseason flush starts. [source] Symptoms associated with malignancy of peripheral nerve sheath tumours: a retrospective study of 69 patients with neurofibromatosis 1BRITISH JOURNAL OF DERMATOLOGY, Issue 1 2005L. Valeyrie-Allanore Summary Background, Neurofibromatosis 1 (NF1) is a common genetic disorder with variable clinical manifestations and an unpredictable course. Plexiform neurofibromas are common complications of NF1. Their malignant transformation is the main cause of mortality in adult patients with NF1. Objectives, To identify clinical factors associated with malignant transformation of plexiform neurofibromas. Methods, Using the database of our neurofibromatosis clinic we included in a retrospective study all patients with NF1 having at least one peripheral nerve sheath tumour for which they underwent surgery or surgical biopsy. Predictive values for malignant transformation of three clinical symptoms, i.e. pain, enlargement of mass and neurological symptoms, were evaluated in association with histological parameters. Results, Of 69 patients studied, 48 had at least one plexiform neurofibroma and 21 had a malignant peripheral nerve sheath tumour. Only enlargement of the tumour had high negative and positive predictive values for malignant transformation: 0·92 and 0·95, respectively. In multivariate analysis, tumour enlargement was independently associated with malignant transformation (odds ratio 167·8, 95% confidence interval 14·0,2012·1). Conclusions, From a practical point of view, pain, neurological deficit and enlargement of a pre-existing peripheral nerve sheath tumour in NF1 must lead to deep surgical biopsy to rule out malignant transformation. [source] Changes in Panayiotopoulos syndrome over timeEPILEPSIA, Issue 2009Giuseppe Capovilla Summary In its first description (1989), Panayiotopoulos syndrome was defined as an idiopathic epilepsy syndrome with an excellent prognosis, characterized by a clinical ictal triad of nocturnal seizures, tonic deviation of the eyes, and vomiting. The electroencephalographic and clinical features of this condition were highly suggestive of occipital lobe involvement. Subsequently, the concept of this benign age-related focal epilepsy has been expanded over the years, including a wider and larger spectrum of seizure manifestations far beyond the occipital manifestations, and for which the eponym of Panayiotopoulos syndrome (PS) has been adopted. However, many theoretical and practical points, including diagnostic, genetic, and pathophysiologic issues remain still unresolved for PS. [source] Shifted factor analysis,Part III: N -way generalization and applicationJOURNAL OF CHEMOMETRICS, Issue 7 2003Sungjin Hong Abstract The ,quasi-ALS' algorithm for shifted factor estimation is generalized to three-way and n -way models. We consider the case in which mode A is the only shifted sequential mode, mode B determines shifts, and modes above B simply reweight the factors. The algorithm is studied using error-free and fallible synthetic data. In addition, a four-way chromatographic data set previously analyzed by Bro et al. (J. Chemometrics 1999; 13: 295,309) is reanalyzed and (two or) three out of four factors are recovered. The reason for the incomplete success may be factor shape changes combined with the lack of distinct shift patterns for two of the factors. The shifted factor model is compared with Parafac2 from both theoretical and practical points of view. Copyright © 2003 John Wiley & Sons, Ltd. [source] ,Weaving thoughts' A method for presenting and commenting psychoanalytic case material in a peer groupTHE INTERNATIONAL JOURNAL OF PSYCHOANALYSIS, Issue 5 2005JOHAN NORMAN The authors argue that there are good reasons for seriously considering the dynamics of the peer group when discussing psychoanalytical case material. The setting and procedure have to protect and facilitate for the presenter and the group members to work together. The aim of this paper is to discuss the problems connected with presenting and discussing clinical psychoanalytical material in a peer group and to describe one such specifi c method, which the authors call the ,weaving thoughts' method. The design is primarily inspired by Bion's formulation ,thoughts in search of a thinker'. The group participants refl ect on the presented clinical material in a way that the authors metaphorically describe as creating a weave of thoughts that emerges from the material. The aim of the method is to facilitate a work-group climate that allows thoughts to wander about, and to avert group members from debating and compromising the integrity of its members by letting basic assumptions come into power. The method is described from theoretical and practical points of view, with two illustrations of seminars according to this design and fi nally a discussion of the advantages and drawbacks of the method. [source] | ||||||||||||||||||||||