Major Problem (major + problem)

Distribution by Scientific Domains
Distribution within Medical Sciences

Selected Abstracts

Does MPA mean ,Major Problem for Assessments'?

Considering the consequences of place-based management systems
Abstract Marine protected areas (MPAs) have been increasingly proposed, evaluated and implemented as management tools for achieving both fisheries and conservation objectives in aquatic ecosystems. However, there is a challenge associated with the application of MPAs in marine resource management with respect to the consequences to traditional systems of monitoring and managing fisheries resources. The place-based paradigm of MPAs can complicate the population-based paradigm of most fisheries stock assessments. In this review, we identify the potential complications that could result from both existing and future MPAs to the science and management systems currently in place for meeting conventional fisheries management objectives. The intent is not to evaluate the effects of implementing MPAs on fisheries yields, or even to consider the extent to which MPAs may achieve conservation oriented objectives, but rather to evaluate the consequences of MPA implementation on the ability to monitor and assess fishery resources consistent with existing methods and legislative mandates. Although examples are drawn primarily from groundfish fisheries on the West Coast of the USA, the lessons are broadly applicable to management systems worldwide, particularly those in which there exists the institutional infrastructure for managing resources based on quantitative assessments of resource status and productivity. [source]

Optimizing in-kind drug donations for Tanzania,a case study

Gaby Gehler Mariacher
Abstract A questionnaire survey (QS) among stakeholders in Tanzania had shown that in-kind drug donations (DDs) are important to boost the drug supply system. Major problems were their insufficient quantity for sustainable treatment and the discrepancy between the needs of the recipients and the donors' supply. Objectives in this study were to discuss these findings and to learn from key informants (KIs) how to improve the DD process. Data were collected through KI interviews in 2001/2002. A 30% gap in drug supply has to be bridged by DDs. KIs confirmed the importance of the World Health Organisation and Tanzanian DD guidelines as a tool for good donation practice and emphasized the role of the government in their implementation. They requested that donors meet the recipient country's regulatory requirements. In contrast to QS respondents, KIs did not view DD quality as a minor problem, and proposed that DD quality should be adapted to the national quality assurance procedures. DD processes could be improved through (a) effective implementation of DD guidelines as an aid for decision-making and for quality assurance, (b) availability of data to improve communication between donors and recipients, (c) transparency between recipients and donors and (d) clearly defined accountability. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Sturgeon aquaculture in China: status of current difficulties as well as future strategies based on 2002,2006/2007 surveys in eleven provinces

By R. Li
Summary A nationwide survey in July and August 2007 employed a representative sample of Chinese sturgeon farms from 2002,2006/2007, including data from previous surveys and official statistics dating back to 1998, showing that the development of China's sturgeon aquaculture has progressed steadily in the past few years. Acipenser baerii and Amur hybrids (Acipenser schrenckii × Huso dauricus) have become the dominant cultured species, accounting for 80% of total production. Production centers moved from the southeastern coast towards the midwestern inland provinces, where cold freshwater resources are available in abundance. The paper presents production trends as well as the price structure for commercial fish/meat and juveniles in the various provinces and also considers import and export data for products, fertilized eggs and fingerlings. Results show that: (i) production of juveniles in hatcheries has risen only slightly during the survey period; (ii) the number of larvae obtained from the wild gradually declines each year; (iii) the price for commercial fish/meat drastically declined between 1998 to 2002, but remained stable from 2002 to 2007; and (iv) total production from the 83 surveyed farms was almost stable from 2002 to 2007. Major problems influencing sustainable development of sturgeon aquaculture were identified, including: (i) insufficient domestic supply of larvae and the ban for commercial use of A. sinensis; (ii) disorganized hybridization; (iii) the potential threat to the genetics of natural stocks in the Yangtze River; (iv) diseases originating from environmental pollution and poor-quality fish feed; (v) limited domestic markets; (vi) low volume of sturgeon export due to lack of intensive processing; and (vii) lack of organizational structure in the industry. [source]

Data processing issues in large-area GPR surveys: correcting trace misalignments, edge discontinuities and striping

Eileen G. Ernenwein
Abstract Ground-penetrating radar (GPR) lags behind other archaeogeophysical methods in terms of speed, efficiency and ability to produce clean site-wide composites owing to complex and time-consuming data processing requirements. Two North American case studies illustrate problems that occur when survey is conducted over long and short periods of time. Some GPR defects have been blamed on differential solar heating of antennae and battery power levels but we show these effects to be negligible. Major problems include gradual changes over time in ground moisture and low-level background noise, which can create discontinuities between adjacent survey blocks when data are collected at different times. These problems are often remedied by globally aligning traces using a stable trace position. Variations in ground moisture through time also cause differences in reflection amplitudes, necessitating different range gain curves to match amplitudes between survey blocks. In some cases changes in ground moisture cause noticeable differences in velocity between survey blocks requiring time-scales to be converted to depths to correctly match the data. These problems must be remedied before horizontal slicing can be considered. Subsequent image processing may also be necessary to generate a seamless mosaic and eliminate striping artefacts commonly seen in slice maps. The latter are probably caused by antenna lift and tilt and can be removed by a de-striping algorithm that uses a one-dimensional low-pass filter to characterize stripes followed by their subtraction from the data. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Agent-Based Interoperability without Product Model Standards

Udo Kannengiesser
A major problem with standard translators is that a seamless data transfer instantly fails when not every translator implements a mapping into or from the standard format. This is frequently the case for large design projects that involve the use of a multitude of heterogeneous tools, possibly in evolving configurations over time. The agent-based approach developed and presented in this article aims to flexibly provide product models in a form adapted to the needs of the particular tools when there is no prior agreement on a common data format. Experiments show the feasibility of this approach as well as its efficacy and efficiency. [source]

FS13.5 Occupational contact dermatitis: printer worker's viewpoints

Terry Brown
Introduction:, Occupational contact dermatitis (OCD) is very common in the printing industry due to contact with chemicals, paper, and wet work. It can be avoided by adequate protective measures, but the effectiveness of intervention depends heavily on the employer's and employee's awareness of this health risk. Objectives:, The study aimed to collect information on the knowledge, attitudes and beliefs of print workers about the risk of OCD and methods of prevention. Methods:, A series of focus groups were held with print workers, health and safety officers and managers to discuss their awareness of dermal risk factors, risk behaviour at work, attitudes to health and safety and options on possible preventive measures. A number of companies were also visited to observe, overtly and covertly, the normal work practices. Results:, OCD was not perceived to be either a major problem or a health and safety priority. There was general agreement about the processes and work practices that could cause skin problems. However, work practices varied considerably and did not always reflect this awareness. There was general concern about the type and availability of personal protective equipment, especially gloves and after-work skin cream. The provision of an occupational health service was generally felt to be inadequate, and no company had a policy in place that specifically addressed skin care. Conclusions:, These findings highlight the urgency to intensify health and safety education on skin care within the printing industry. Recommendations were developed for the evaluation of a series of risk reduction strategies. [source]

Minimizing Postoperative Drainage with 20% Ferric Chloride After Chemical Matricectomy with Phenol

A. Burhan Aksakal MD
Background. Phenol used in partial matricectomy shows its effects by denaturing matrix proteins. This highly successful method has the major problem of oozing which can continue for 5,6 weeks. Objective. The goal of this study was to determine the effect of 20% ferric chloride (FC) (FeCl3) on minimizing the oozing after chemical matricectomy with phenol. Methods. Sixty-seven patients with stage III onychocryptosis were treated by chemical matricectomy with 90% aqueous phenol. In 32 of these patients FC was applied to the nail bed after the phenolization procedure. Results. We found a statistically significant (P < .001) reduction of oozing in the FC-applied group of patients. Conclusion. We think that using FC after phenol chemical matricectomy results in a significant reduction in oozing from the operation site. [source]

Patient and direct-care staff body mass index in a state mental hospital: implications for management

W. V. R. Vieweg
Objective:, Obesity is a major problem among chronically psychotic patients. Method:, We assessed body mass index (BMI) of chronically psychotic patients on admission to a state mental hospital and in follow-up. We also compared patient BMI to staff BMI. Results:, The initial patient BMI (26.4 ± 5.8 kg/m2) was in the overweight range. The patient BMI (29.1 ± 5.8 kg/m2) increased (P < 0.0001) on follow-up and almost reached the level of obesity. Staff BMI (35.1 ± 8.6 kg/m2) was in the obese range with 64.9% meeting criteria of obesity and 29.9% meeting criteria of morbid obesity. African-American women made up 84.5% of clinical-care staff and constitute the race,sex mix most vulnerable to obesity in the US. Morbid obesity (BMI , 40 kg/m2) was five times more common among these African-American female clinical-care staff than among African-American women in the general US population. Conclusion:, Our findings may have treatment implications for chronically psychotic patients at risk for obesity. [source]

Novel agents to override imatinib resistance mechanisms

Asumi Yokota
Abstract Chronic myelogenous leukemia (CML) is a disorder of hematopoietic stem cells that results from the Philadelphia chromosome (Ph) created through translocation of human chromosomes 9 and 22. The resulting Bcr-Abl fusion protein has constitutively high tyrosine kinase activity that causes transformation of hematopoietic stem cells. Imatinib mesylate (IM) was developed as a specific Bcr-Abl kinase inhibitor and is efficacious in treating Ph-chromosome-positive (Ph+) leukemias such as CML and Ph+ acute lymphoblastic leukemia (ALL). Within a few years of its introduction to the clinic, IM has dramatically altered the first-line therapy for CML. Although most newly diagnosed CML patients in the chronic phase (CP) achieved durable responses when treated with IM, resistance to IM has become a major problem in patients with advanced-stage disease. The most important mechanism of IM resistance are point mutations within the Abl kinase domain; therefore, there is an urgent need for novel agents that can inhibit mutated Bcr-Abl. In this review, we describe novel Bcr-Abl tyrosine kinase inhibitors, the so-called "Super Gleevec" inhibitors. Drug Dev Res 69:398,406, 2008. © 2008 Wiley-Liss, Inc. [source]

Edible insects: Traditional knowledge or western phobia?

Alan L. YEN
Abstract With an increasing human population and environmental degradation, the world faces a major problem in providing adequate animal based proteins. Many traditional societies have used or still use insects as a protein source, while westernized societies are reluctant to use insects, despite being the major consumers of animal proteins. We now need to consider insects as a source of food for humans in a manner that acknowledges both the role of entomophagy in indigenous societies and the need for westernized societies to reduce the size of their environmental footprint with regard to food production. The situation on continents such as Africa, Asia, and Central and South America has some parallels to Australia in that there are two forces in operation: the sustainable traditional use of edible insects and the "westernization" of these societies leading to a movement away from entomophagy. However, the potential to reach a compromise is greater in these continents because entomophagy is already accepted. The major challenges will be establishing sustainable production systems that include food safety and security as well as environmental protection. Whether this will happen or not will depend upon: (i) a major change in attitude in westernized societies towards entomophagy; (ii) pressure to conserve remaining habitats in a sustainable manner; (iii) economic impetus to develop food production systems that include insects; and (iv) an acknowledgement that achieving adequate nutrition on a global basis will involve different diets in much of the developed world. [source]

Performance of a full-scale biotrickling filter treating H2S at a gas contact time of 1.6 to 2.2 seconds

David Gabriel
Emission of objectionable odors is a major problem for wastewater treatment and other processing facilities. Biological treatment is a promising alternative to conventional control methods, such as chemical scrubbing, but historically, biotreatment has always required significantly larger reactor volumes than chemical scrubbers. In this paper, we present several aspects of the operation and performance of a chemical scrubber, retrofitted to operate as a biotrickling filter treating 16,000 m3 h,1 of foul air with the original gas contact time of 1.6 to 2.2 seconds. In continuous operation for more than a year, the biotrickling filter has shown stable performance and robust behavior for H2S treatment, with pollutant removal performance comparable to using a chemical scrubber. Reclaimed water was used as a nutrient source for the process, and to maintain the pH in the biotrickling filter between 1.5 and 2.2. At a gas contact time of 1.6 seconds, H2S removal was in excess of 95% for sustained inlet H2S concentrations as high as 30 ppmv. This corresponds to volumetric elimination rates of 95 to 105 g H2S m,3 h,1. Efficiencies of about 90% were observed under transient conditions at 2.2 seconds gas contact time for inlet concentration peaks up to 60 ppmv. The biotrickling filter also removed significant amounts of reduced sulfur compounds, ammonia, and volatile organic compounds present in traces in the air, which is important in practical applications. Selected experiments, such as intermittent trickling operation and a one-month operation period at neutral pH, are also presented. Results indicate that the intermittent trickling operation does not have a significant effect on H2S removal. However, when operated at neutral pH, biotrickling filter performance clearly decreased, probably due to an excessive chlorine supply to the reactor through the make-up water. The study demonstrates that biotrickling filters can replace chemical scrubbers as a safer, more economical technique for odor control. [source]

PRECLINICAL STUDY: Conditioned cues and yohimbine induce reinstatement of beer and near-beer seeking in Long-Evans rats

Jemma K. Richards
ABSTRACT Alcohol use disorders (AUDs) impact millions of individuals, yet there are few effective treatments. One major problem in treating AUDs is the high rate of relapse to drinking often induced by stress and/or anxiety states. Although beer accounts for over 81% of all alcohol consumed in hazardous amounts in the United States, the use of beer in pre-clinical research has been limited. It has been shown that rats will self-administer beer and near-beer using a standard operant self-administration paradigm; however, there have been few studies examining reinstatement of beer and near-beer seeking. We have determined that reward-associated cues and/or yohimbine will induce reinstatement of beer and near-beer seeking in a similar manner to that seen for 10% ethanol and sucrose seeking using standard operant self-administration and reinstatement paradigms. We show that rats will self-administer beer, near-beer and 4.5% ethanol using an operant self-administration paradigm and both conditioned cues, and yohimbine will induce reinstatement of beer, near-beer and 4.5% ethanol seeking in previously extinguished animals. This demonstrates that both environmental cues and yohimbine-stress will reinstate beer and near-beer seeking, as previously shown for both 10% ethanol and sucrose seeking. [source]

Guidelines on use of anti-IFN- , antibody measurements in multiple sclerosis: report of an EFNS Task Force on IFN- , antibodies in multiple sclerosis

P. S. Sørensen
Therapy-induced binding and neutralizing antibodies is a major problem in interferon (IFN)- , treatment of multiple sclerosis. The objective of this study was to provide guidelines outlining the methods and clinical use of the measurements of binding and neutralizing antibodies. Systematic search of the Medline database for available publications on binding and neutralizing antibodies was undertaken. Appropriate publications were reviewed by one or more of the task force members. Grading of evidence and recommendations was based on consensus by all task force members. Measurements of binding antibodies are recommended for IFN- , antibody screening before performing a neutralizing antibody (NAB) assay (Level A recommendation). Measurement of NABs should be performed in specialized laboratories with a validated cytopathic effect assay or MxA production assay using serial dilution of the test sera. The NAB titre should be calculated using the Kawade formula (Level A recommendation). Tests for the presence of NABs should be performed in all patients at 12 and 24 months of therapy (Level A recommendation). In patients who remain NAB-negative during this period measurements of NABs can be discontinued (Level B recommendation). In patient with NABs, measurements should be repeated, and therapy with IFN- , should be discontinued in patients with high titres of NABs sustained at repeated measurements with 3- to 6-month intervals (Level A recommendation). [source]

A genetic algorithm multi-objective approach for efficient operational planning technique of distribution systems

C. Lakshminarayana
Abstract This paper presents a genetic algorithm multi-objective approach for efficient operational planning technique for electrical power distribution systems (EPDS). Service restoration is a non-linear, combinatorial, non-differential and multi-objective optimization problem that often has a great number of candidate solutions to be evaluated by the operators. To tackle the problem of service restoration with multiple objectives, the weighted sum strategy is employed to convert these objectives into a single objective function by giving equal weighting values. The transformer/feeders capacity in the post-fault distribution network creates a major problem for the electrical power distribution engineers and distribution system substation operators to satisfy the operational constraints at the consumer localities while restoring power supply. The feasibility of the developed algorithm for service restoration demonstrated on several distribution networks with fast and effective convergence of the results of this technique helps to find the efficient operational planning of the EPDS. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Microarray analysis yields candidate markers for rotation resistance in the western corn rootworm beetle, Diabrotica virgifera virgifera

Lisa M. Knolhoff
Abstract As pest species may evolve resistance to chemical controls, they may also evolve resistance to cultural control methods. Yearly rotation of corn (Zea mays) with another crop interrupts the life cycle of the western corn rootworm beetle (Diabrotica virgifera virgifera, Coleoptera: Chrysomelidae), but behavioral resistance to crop rotation is now a major problem in the Midwest of the USA. Resistant adult females exhibit reduced fidelity to corn as a host and lay their eggs in the soil of both corn and soybean (Glycine max) fields. Behavioral assays suggest that the adaptation is related to increased locomotor activity, but finding molecular markers has been difficult. We used microarray analysis to search for gene expression differences between resistant and wild-type beetles. Candidates validated with real-time polymerase chain reaction exhibit predicted patterns from the microarray in independent samples across time and space. Many genes more highly expressed in the rotation-resistant females have no matches to known proteins, and most genes that were more lowly expressed are involved in antimicrobial defense. [source]

Cell wall hemicelluloses as mobile carbon stores in non-reproductive plant tissues

Summary 1As essential compounds of plant cell walls, hemicelluloses account for about a quarter of all plant biomass worldwide. 2In seed cotyledons and endosperm of species from several plant families, hemicelluloses are used as mobile carbon reserves. Whether cell wall hemicelluloses of non-reproductive plant tissue are multifunctional molecules, which can also serve as carbon sources during periods of enhanced carbon demand, is still equivocal. 3This review summarizes the current understanding of a possible reserve function of hemicelluloses. Although several descriptive and experimental studies suggested at least partial mobility of cell wall polysaccharides in mature, non-reproductive plant tissues, there is still a need for a broad-scale, ecophysiological exploration of the actual nature of hemicelluloses beyond their structural function. 4The chemical heterogeneity of hemicelluloses may be the major problem for precise quantitative analyses on a large, comparative scale. 5Because of the abundant distribution of hemicelluloses in plants, the existence of a significant mobile carbohydrate pool in cell walls of non-reproductive organs would shed rather new light on plant carbon relations in a source-sink context. 6Consequently, a reserve function of hemicelluloses questions the conventional division of cell compounds into structural (i.e. immobile) and non-structural (i.e. mobile) compounds. [source]

Evaluations of maximization procedures for estimating linkage parameters under heterogeneity

Swati Biswas
Abstract Locus heterogeneity is a major problem plaguing the mapping of disease genes responsible for complex genetic traits via linkage analysis. A common feature of several available methods to account for heterogeneity is that they involve maximizing a multidimensional likelihood to obtain maximum likelihood estimates. The high dimensionality of the likelihood surface may be due to multiple heterogeneity (mixing) parameters, linkage parameters, and/or regression coefficients corresponding to multiple covariates. Here, we focus on this nontrivial computational aspect of incorporating heterogeneity by considering several likelihood maximization procedures, including the expectation maximization (EM) algorithm and the stochastic expectation maximization (SEM) algorithm. The wide applicability of these procedures is demonstrated first through a general formulation of accounting for heterogeneity, and then by applying them to two specific formulations. Furthermore, our simulation studies as well as an application to the Genetic Analysis Workshop 12 asthma datasets show that, among other observations, SEM performs better than EM. As an aside, we illustrate a limitation of the popular admixture approach for incorporating heterogeneity, proved elsewhere. We also show how to obtain standard errors (SEs) for EM and SEM estimates, using methods available in the literature. These SEs can then be combined with the corresponding estimates to provide confidence intervals of the parameters. © 2004 Wiley-Liss, Inc. [source]

Wind erosion and intensive prehistoric agriculture: A case study from the Kalaupapa field system, Moloka'i Island, Hawai'i

Mark D. McCoy
Wind erosion is a major problem for modern farmers, a key variable affecting nutrient levels in ecosystems, and a potentially major force impacting archaeological site formation; however, it has received scant consideration in geoarchaeological studies of agricultural development compared with more easily quantifiable environmental costs, such as vegetation change or fluvial erosion. In this study, soil nutrient analysis is used in the Kalaupapa field system, Moloka'i Island, Hawai'i, to detect an increase in wind erosion attributable to intensive agriculture following the burning of endemic forest. This practice began on a small scale in the 13th century A.D., expanded around cal A.D. 1450,1550, and continued until the near total abandonment of the fields after European contact in the 18th century. Nutrients that naturally occur in high amounts in coastal windward areas due to the long-term, cumulative effect of sea spray were especially impacted. However, thanks to the unique landform of the Kalaupapa Peninsula, nutrient depletion in windward areas was offset by downwind enrichment and likely contributed to the long-term sustainability of the system as a whole. Future research on tropical and arid agriculture should consider the cumulative environmental cost of increased eolian erosion attributable to anthropogenic landscape modification. © 2007 Wiley Periodicals, Inc. [source]

Physician characteristics associated with prescription of inappropriate medications using Beers criteria

Hirohisa Imai
Background: The prescription of potentially inappropriate medications (PIM) for elderly patients represents a major problem. In the published work, various practice characteristics associated with physicians prescribing habits have been reported. However, existing data has shed little light on the characteristics of physicians who tend to prescribe PIM. We examined whether personal, professional or practice characteristics differ between physicians who prescribe PIM and those who do not. Methods: The subjects comprised primary care and general practice physicians. Physicians were identified from the pharmacy database of a managed care organization as having prescribed medications for Medicare patients over 65 years enrolled in a managed care plan. We adopted Beers criteria to describe the prevalence of PIM use. The physicians were divided into three groups according to number of PIM prescribed. To examine the extent of associations between all the physician-related characteristics studied, polychotomous logistic regression was conducted. Results: Physicians who prescribed one to five PIMs were 0.63 (95% confidence interval [CI], 0.41,0.98) times more likely to have publications than physicians who prescribed no PIM. Physicians who prescribed more than six PIM were 3.18 (95% CI, 2.05,4.95) times more likely to be certified by an internal medicine board, 0.48 (95% CI, 0.30,0.78) times more likely to have publications, and 1.84 (95% CI, 1.01,3.35) times more likely to be in solo practice than physicians who prescribed no PIM. Conclusion: In this study, we found three predictors of PIM prescribing incidence. Since the current study could only describe associations and not causality, further research is necessary. [source]

The Crisis in the Investiture Crisis Narrative

Maureen C. Miller
Recent research has undermined the connection between lay investiture and the iconic event usually seen as the most dramatic expression of the investiture conflict: the encounter of Pope Gregory VII and King Henry IV of Germany at Canossa. This is just one, however, of many interpretive problems plaguing historical narratives of the investiture crisis. This essay briefly summarizes the classic interpretations that have dominated 20th-century understanding of these events and sets out the major problem raised in more recent research. Arguing that a new interpretive framework is necessary, the author suggests two paths forward: a radical reconsideration of the papacy from a truly post-confessional perspective and a reevaluation of the conflict in the context of new understandings of lordship and political change. [source]

Correction for pulse height variability reduces physiological noise in functional MRI when studying spontaneous brain activity

Petra J. van Houdt
Abstract EEG correlated functional MRI (EEG-fMRI) allows the delineation of the areas corresponding to spontaneous brain activity, such as epileptiform spikes or alpha rhythm. A major problem of fMRI analysis in general is that spurious correlations may occur because fMRI signals are not only correlated with the phenomena of interest, but also with physiological processes, like cardiac and respiratory functions. The aim of this study was to reduce the number of falsely detected activated areas by taking the variation in physiological functioning into account in the general linear model (GLM). We used the photoplethysmogram (PPG), since this signal is based on a linear combination of oxy- and deoxyhemoglobin in the arterial blood, which is also the basis of fMRI. We derived a regressor from the variation in pulse height (VIPH) of PPG and added this regressor to the GLM. When this regressor was used as predictor it appeared that VIPH explained a large part of the variance of fMRI signals acquired from five epilepsy patients and thirteen healthy volunteers. As a confounder VIPH reduced the number of activated voxels by 30% for the healthy volunteers, when studying the generators of the alpha rhythm. Although for the patients the number of activated voxels either decreased or increased, the identification of the epileptogenic zone was substantially enhanced in one out of five patients, whereas for the other patients the effects were smaller. In conclusion, applying VIPH as a confounder diminishes physiological noise and allows a more reliable interpretation of fMRI results. Hum Brain Mapp, 2010. © 2009 Wiley-Liss, Inc. [source]

Functional analysis helps to clarify the clinical importance of unclassified variants in DNA mismatch repair genes,

HUMAN MUTATION, Issue 11 2007
Jianghua Ou
Abstract Hereditary nonpolyposis colorectal cancer (HNPCC) or Lynch syndrome is caused by DNA variations in the DNA mismatch repair (MMR) genes MSH2, MLH1, MSH6, and PMS2. Many of the mutations identified result in premature termination of translation and thus in loss-of-function of the encoded mutated protein. These DNA variations are thought to be pathogenic mutations. However, some patients carry other DNA mutations, referred to as unclassified variants (UVs), which do not lead to such a premature termination of translation; it is not known whether these contribute to the disease phenotype or merely represent rare polymorphisms. This is a major problem which has direct clinical consequences. Several criteria can be used to classify these UVs, such as: whether they segregate with the disease within pedigrees, are absent in control individuals, show a change of amino acid polarity or size, provoke an amino acid change in a domain that is evolutionary conserved and/or shared between proteins belonging to the same protein family, or show altered function in an in vitro assay. In this review we discuss the various functional assays reported for the HNPCC-associated MMR proteins and the outcomes of these tests on UVs identified in patients diagnosed with or suspected of having HNPCC. We conclude that a large proportion of MMR UVs are likely to be pathogenic, suggesting that missense variants of MMR proteins do indeed play a role in HNPCC. Hum Mutat 28(11), 1047,1054, 2007. © 2007 Wiley-Liss, Inc. [source]

Implementing quality control on a random number stream to improve a stochastic weather generator,,

Charles R. Meyer
Abstract For decades, stochastic modellers have used computerized random number generators to produce random numeric sequences fitting a specified statistical distribution. Unfortunately, none of the random number generators we tested satisfactorily produced the target distribution. The result is generated distributions whose mean even diverges from the mean used to generate them, regardless of the length of run. Non-uniform distributions from short sequences of random numbers are a major problem in stochastic climate generation, because truly uniform distributions are required to produce the intended climate parameter distributions. In order to ensure generation of a representative climate with the stochastic weather generator CLIGEN within a 30-year run, we tested the climate output resulting from various random number generators. The resulting distributions of climate parameters showed significant departures from the target distributions in all cases. We traced this failure back to the uniform random number generators themselves. This paper proposes a quality control approach to select only those numbers that conform to the expected distribution being retained for subsequent use. The approach is based on goodness-of-fit analysis applied to the random numbers generated. Normally distributed deviates are further tested with confidence interval tests on their means and standard deviations. The positive effect of the new approach on the climate characteristics generated and the subsequent deterministic process-based hydrology and soil erosion modelling are illustrated for four climatologically diverse sites. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Assessing the reliability of biodiversity databases: identifying evenly inventoried island parasitoid faunas (Hymenoptera: Ichneumonoidea) worldwide

Abstract., 1.,Taxonomic and geographic biases are common in biodiversity inventories, especially in hyperdiverse taxa, such as the Ichneumonoidea. Despite these problems, biodiversity databases could be a valuable source of information if their reliability is carefully assessed. 2.,One major problem of using these data for large-scale analyses is the unevenness of data quality from different areas, which makes them difficult to compare. One way of surpassing such problem would be to identify sets of areas that are evenly inventoried. 3.,Here, we propose a scoring protocol for the identification of sets of evenly inventoried areas from taxonomic databases, based on three criteria: (i) completeness at high taxonomic levels, (ii) congruence with well-established ecological relationships (such as species,area relationship), and (iii) publication effort received. We apply this protocol to the selection of a set of evenly inventoried islands worldwide for two Ichneumonoidea families (Braconidae and Ichneumonidae) from the data gathered in Taxapad database. 4.,From the 118 islands included in Taxapad, 53 and 70 can be considered sufficiently inventoried for Braconidae and Ichneumonidae, respectively. The publication effort criterion was more restrictive than the other two criteria. The Indomalayan, Nearctic and Palearctic regions had more than half of their islands identified as evenly inventoried, for both families. 5.,We discuss the generality of the biases and incompleteness of most biodiversity data, and also how the basic principles of the protocol proposed here can be applied to taxonomic databases devoted to other taxa. Also, the islands identified here can serve as the basis for large-scale analyses of the poorly known biogeography of the Ichneumonoidea. [source]

Adaptive mesh technique for thermal,metallurgical numerical simulation of arc welding processes

M. Hamide
Abstract A major problem arising in finite element analysis of welding is the long computer times required for a complete three-dimensional analysis. In this study, an adaptative strategy for coupled thermometallurgical analysis of welding is proposed and applied in order to provide accurate results in a minimum computer time. The anisotropic adaptation procedure is controlled by a directional error estimator based on local interpolation error and recovery of the second derivatives of different fields involved in the finite element calculation. The methodology is applied to the simulation of a gas,tungsten-arc fusion line processed on a steel plate. The temperature field and the phase distributions during the welding process are analyzed by the FEM method showing the benefits of dynamic mesh adaptation. A significant increase in accuracy is obtained with a reduced computational effort. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Characteristics of skin aging in Korean men and women

J. H. Chung
Introduction Korea is located between Japan and Mainland China. The people of these three countries have similar appearances and it is difficult to differentiate between them. Although the population of Asia is more than half of the total population of the Earth, the inherent characteristics of Asian skin have not been well investigated. Commercial markets for cosmetics and drugs for photoaged skin are rapidly expanding in many Asian countries. Therefore, many investigators in the field of dermatology and cosmetology have become interested in brown Asian skin. Clinical characteristics of skin aging and photoaging in Asians Skin aging can be divided into two basic processes: intrinsic aging and photoaging [1]. Intrinsic aging is characterized by smooth, dry, pale, and finely wrinkled skin, whereas photoaging, which indicates premature skin aging in chronically photodamaged skin, is characterized by severe wrinkling and irregular pigmentation. The pattern of wrinkling in Asians seems to differ from that in Caucasians. Asians have coarser, thicker and deep wrinkles, particularly in the forehead, perioral and Crow's foot areas. In contrast, Caucasians usually have relatively fine cheek and Crow's foot wrinkles. The reasons for these differences are not known and need further investigation. There are racial, ethnic and genetic differences, and differences of skin structure and function, between the brown skin of Asians and the white skin of Caucasians. As Asian skin is more pigmented, acute and chronic cutaneous responses to UV irradiation differ from those in white skin. Many people believe, based on clinical impressions, that the main process of photoaging in Asians involves pigmentary changes, rather than wrinkling. However, no study has been performed to confirm this belief. Risk factors for skin wrinkles and their relative risks in Korean skin [2] Various factors such as age, sun-exposure, and smoking are known to be important risk factors for wrinkles. However, the relative risks of each factor on wrinkles in the brown skin of Asians have not been investigated, and they could differ from those in Caucasians. An evaluation system for skin wrinkling is necessary for Asian skin [3]. Thus, we developed an eight-point photographic scale for assessing wrinkles in both Korean genders [2]. This scale can probably be applied to the populations of other Asian countries, at least to the Japanese and Chinese. The pattern of wrinkles in both genders appears to be similar. Age Age is an important risk factor for wrinkling in Asians, as in Caucasians. Korean subjects in their 60s showed a 12-fold increased risk of wrinkling, while subjects in their 70s have a 56-fold increased risk compared with young age group. UV light It is well known that the UV component in sunlight can cause and accelerate photoaging. The pigmented skin of Asian may better protect skin from acute and chronic UV damage. However, we found a strong association between sun-exposure and the development of wrinkling in Koreans. It was found that sun exposure of more than 5 h per day was associated with a 4.8-fold increased risk in wrinkling versus less than 2 h of sun-exposure in Koreans. Estrogen deficiency Korean females have more wrinkles than men, after controlling for age, sun exposure, and smoking, it was found that they have a 3.6-fold increased risk of developing wrinkles than their male counterparts [2]. It has also been reported, that the relative risk for wrinkling in women is higher than in men as for in white Caucasians [4]. The reason why women show more wrinkles remains to be determined. It is possible that a reduction in skin collagen because of estrogen deficiency in postmenopausal woman may aggravate wrinkling severity. Korean women with more than 10 years since menopause showed a 3.9-fold higher risk of wrinkling than the women 5 years of beyond menopause [5]. We demonstrated that women with a history of HRT have a significantly lower risk, more specifically, one fifth of the risk of facial wrinkling relative to those who had no history of HRT. Interestingly, we found that wrinkle severity significantly increased with an increasing number of full term pregnancies. The relative risk for severe wrinkling is increased by approximately 1.8-fold per full term pregnancy. Smoking It is known that smoking causes skin wrinkling in Caucasians, and that it plays no role in Blacks [6, 7]. Koreans with have a smoking history of more than 30 pack years showed a more than 2.8-fold increased risk of wrinkles [2]. The relative risks of wrinkles associated with a 30,50 pack-years history of smoking were 2.8- and 5.5-fold, respectively. Dyspigmentation in Asian skin To follow pigmentary changes, six photographic standards for both genders were developed for Korean skin, to produce a 6-point scale [2, 8]. Hyperpigmented spots, mostly lentigines, were prominent among women, while seborrheic keratosis tended to be more prominent in men. Seborrheic keratosis in Korean men Seborrheic keratoses (SKs) are benign cutaneous tumors. They have diverse clinical and histopathological appearances and are very common in the elderly (over 50 years old). The etiology of SKs is not well understood, although patients with a great number of lesionsshow a familial trait with an autosomal dominant pattern, and human papilloma virus has been suggested as possible cause because of verrucous appearance of the lesions. Exposure to sunlight has been suggested to be a risk factor for SKs. However, there is still some debate in terms of the role of sunlight. Recently, we have investigated the clinical characteristics of SKs and relationship between SKs and sunlight exposure in Korean males [9]. The prevalence of SKs in Koreans increases with age; it rose from 78.9% at 40 years, to 93.9% at 50 years and 98.7% in those over 60 years. Exposed areas, i.e. the face, neck and dorsum of the hands, demonstrate a significant increase in the prevalence of SKs by decade, whereas partly exposed areas, although SKs tended to increase in prevalence with age, this trend was not significant. When the estimated body surface area (BSA) is taken into account, the number of SKs on both the face and dorsum of the hands (0.51 ± 0.08 per 1% BSA) was over-represented compared with the trunk. SKs were also concentrated on the neck (0.38 ± 0.07 per 1% BSA) and in the V-area (0.47 ± 0.09 per 1% BSA). Outer forearms also showed 3-fold more SKs per unit area than neighboring arms and inner forearms, which are classified as partly exposed area (0.09 ± 0.02, 0.03 ± 0.01, respectively). The total area covered by SKs on exposed area also became significantly larger with aging than on intermittently exposed areas. These results indicate that exposure to sunlight might be related to SK growth. Our results indicated that excessive sun exposure is an independent risk factor of SKs. After controlling for age, smoking, and skin type, subjects with a sun exposure history of more than 6 hours per day showed a 2.28-fold increased risk of having severe SKs (n , 6) compared with those exposed for less that 3 h per day. These findings indicated that sun-exposure may play an important role in SK development. In summary, SKs are very common in Korean males and represent one of the major pigmentary problems. SKs concentrate on exposed skin, especially on the face and dorsum of the hands. Both age and lifetime cumulative sunlight exposure are important contributing factors and may work in a synergistic manner. Conclusion Many people tend to believe that wrinkles are not a prominent feature of Asian photoaged skin, and that dyspigmentation is a major manifestation in Asian skin. Contrary to this impression, wrinkling is also a major problem in the photoaged skin of Asians, and Korean people showing severe pigmentary changes usually tend to have severe wrinkles. In conclusion, the wrinkling patterns and pigmentary changes of photoaged skin in East Asians differ from those of Caucasians, and the relative risks of aggravating factors may be different from those of Caucasian skin. References 1.,Gilchrest, B.A. Skin aging and photoaging: an overview. J. Am. Acad. Dermatol. 21, 610,613 (1989). 2.,Chung, J.H. et al. Cutaneous photodamage in Koreans: influence of sex, sun exposure, smoking, and skin color. Arch. Dermatol. 137, 1043,1051 (2001). 3.,Griffiths, C.E. et al. A photonumeric scale for the assessment of cutaneous photodamage. Arch. Dermatol. 128, 347,351 (1992). 4.,Ernster, V.L. et al. Facial wrinkling in men and women, by smoking status. Am. J. Public Health. 85, 78,82 (1995). 5.,Youn, C.S. et al. Effect of pregnancy and menopause on facial wrinkling in women. Acta Derm. Venereol. 83, 419,424 (2003). 6.,Kadunce, D.P. et al. Cigarette smoking: risk factor for premature facial wrinkling. Ann. Intern. Med. 114, 840,844 (1991). 7.,Allen, H.B., Johnson, B.L. and Diamond, S.M. Smoker's wrinkles? JAMA. 225, 1067,1069 (1973). 8.,Chung, J.H. Photoaging in Asians. Photodermatol. Photoimmunol. Photomed. 19, 109,121 (2003). 9.,Kwon, O.S. et al. Seborrheic keratosis in the Korean males: causative role of sunlight. Photodermatol. Photoimmunol. Photomed. 19, 73,80 (2003). [source]

Causes of hair loss and the developments in hair rejuvenation

D. H. Rushton
Synopsis Hair is considered to be a major component of an individual's general appearance. The psychological impact of hair loss results in a measurably detrimental change in self-esteem and is associated with images of reduced worth. It is not surprising that both men and women find hair loss a stressful experience. Genetic hair loss is the major problem affecting men and by the age of 50, up to 50% will be affected. Initial attempts to regenerate the lost hair have centred on applying a topical solution of between 2% to 5% minoxidil; however, the results proved disappointing. Recently, finasteride, a type II 5, reductase inhibitor has been found to regrow a noticeable amount of hair in about 40% of balding men. Further developments in treatments have lead to the use of a dual type I and type II inhibitor where 90% of those treated regrow a noticeable amount of hair. In women the major cause of hair loss before the age of 50 is nutritional, with 30% affected. Increased and persistent hair shedding (chronic telogen effluvium) and reduced hair volume are the principle changes occurring. The main cause appears to be depleted iron stores, compromised by a suboptimal intake of the essential amino acid l -lysine. Correction of these imbalances stops the excessive hair loss and returns the hair back to its former glory. However, it can take many months to redress the situation. Résumé Les cheveux sont considérés comme étant une composante majeure de l'aspect général d'un individu. L'impact psychologique de la perte des cheveux conduit à une diminution mesurable de l'estime de soi et s'associe à des images de contexte négatif. Il n'est pas surprenant que les hommes comme les femmes ressentent la perte de cheveux comme une expérience stressante. La perte génétique des cheveux est le problème principal qui touche les hommes et autour de l'âge de 50 ans, jusqu'à 50% seront concernés. Les premières tentatives de régénération des cheveux perdus se sont focalisées sur l'application topique d'une solution comprenant entre 2% et 5% de minoxidil; cependant, les résultats se sont avérés décevants. Récemment, le finastéride, un inhibiteur de la 5,-réductase de type II s'est avéré permettre la repousse d'une quantité significative de cheveux chez environ 40% des hommes dégarnis. Les développements ultérieurs des traitements ont conduit à l'utilisation d'un inhibiteur associant type I et type II pour lequel 90% des personnes traitées constatent une repousse significative des cheveux. Chez les femmes la cause principale de la perte des cheveux avant l'âge de 50 ans est d'origine nutritionnelle, avec 30% de la population affectée. Une perte de cheveux persistante et croissante (telogen effluvium chronique) et un volume des cheveux réduit sont les principaux effets qui se produisent. La cause principale semble être des réserves de fer épuisées, associées à une prise insuffisante de l'acide aminé essentiel L-lysine. La correction de ces déséquilibres stoppe la perte excessive de cheveux et rend aux cheveux leur éclat d'antan. Cependant, plusieurs mois peuvent être nécessaires pour redresser la situation. [source]

The relevance of a geriatric sub-classification of personality disorders in the DSM-V

S. P. J. van Alphen
Abstract Little is known about the course of personality disorders across the life span. A major problem is that the current DSM nosology for personality disorders does not account for age-associated changes in behaviour and interpersonal functioning. This editorial will discuss the main diagnostic bottlenecks when applying the current DSM-IV-TR Axis II criteria to older adults. Subsequently, suggestions will be given for future research and the development of a geriatric sub-classification. Copyright © 2006 John Wiley & Sons, Ltd. [source]

The course of neuropsychiatric symptoms in dementia.

Part I: findings from the two-year longitudinal Maasbed study
Abstract Background Although neuropsychiatric symptoms in dementia are common, there have been few large long-term prospective studies assessing the course of a broad range of neuropsychiatric symptoms in dementia. Objectives To investigate the course of neuropsychiatric symptoms in patients with dementia, including data about prevalence, incidence and persistence. Methods One hundred and ninety-nine patients with dementia were assessed every six months for two-years, using the Neuropsychiatric Inventory (NPI) to evaluate neuropsychiatric symptoms. Results Nearly all patients (95%) developed one or more neuropsychiatric symptoms in the two-year study period. Mood disorders were the most common problem. The severity of depression decreased, whereas the severity of apathy and aberrant motor behaviour increased during follow-up. The cumulative incidence was highest for hyperactive behaviours and apathy. Overall behavioral problems were relatively persistent, but most symptoms were intermittent, with apathy and aberrant motor behaviour being persistent for longer consecutive periods. Conclusions Neuropsychiatric symptoms in dementia are a common and major problem. Different symptoms have their own specific course, most of the time show a intermittent course, but behavioural problems overall are chronically present. The data have implications for developing treatment strategies. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Prescription practices of public and private health care providers in Attock District of Pakistan

S. Siddiqi
Abstract The irrational use of drugs is a major problem of present day medical practice and its consequences include the development of resistance to antibiotics, ineffective treatment, adverse effects and an economic burden on the patient and society. A study from Attock District of Pakistan assessed this problem in the formal allopathic health sector and compared prescribing practices of health care providers in the public and private sector. WHO recommended drug use indicators were used to study prescription practices. Prescriptions were collected from 60 public and 48 private health facilities. The mean (±,SE) number of drugs per prescription was 4.1,±,0.06 for private and 2.7,±,0.04 for public providers (,p,<,0.0001). General practitioners (GPs) who represent the private sector prescribed at least one antibiotic in 62% of prescriptions compared with 54% for public sector providers. Over 48% of GP prescriptions had at least one injectable drug compared with 22.0% by public providers (,p,<,0.0001). Thirteen percent of GP prescriptions had two or more injections. More than 11% of GP prescriptions had an intravenous infusion compared with 1% for public providers (,p,<,0.001). GPs prescribed three or more oral drugs in 70% of prescriptions compared with 44% for public providers (,p,<,0.0001). Prescription practices were analysed for four health problems, acute respiratory infection (ARI), childhood diarrhoea (CD), fever in children and fever in adults. For these disorders, both groups prescribed antibiotics generously, however, GPs prescribed them more frequently in ARI, CD and fever in children (,p,<,0.01). GPs prescribed steroids more frequently, however, it was significantly higher in ARI cases (,p,<,0.001). For all the four health problems studied, GPs prescribed injections more frequently than public providers (,p,<,0.001). In CD cases GPs prescribed oral rehydration salt (ORS) less frequently (33.3%) than public providers (57.7%). GPs prescribed intravenous infusion in 12.3% cases of fever in adults compared with none by public providers (,p,<,0.001). A combination of non-regulatory and regulatory interventions, directed at providers as well as consumers, would need to be implemented to improve prescription practices of health care providers. Regulation alone would be ineffective unless it is supported by a well-established institutional mechanism which ensures effective implementation. The Federal Ministry of Health and the Provincial Departments of Health have to play a critical role in this respect, while the role of the Pakistan Medical Association in self-regulation of prescription practices can not be overemphasized. Improper prescription practices will not improve without consumer targeted interventions that educate and empower communities regarding the hazards of inappropriate drug use. Copyright © 2002 John Wiley & Sons, Ltd. [source]