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Common Practice (common + practice)
Selected AbstractsIllustrative Hybrid Visualization and Exploration of Anatomical and Functional Brain DataCOMPUTER GRAPHICS FORUM, Issue 3 2008W. M. Jainek Abstract Common practice in brain research and brain surgery involves the multi-modal acquisition of brain anatomy and brain activation data. These highly complex three-dimensional data have to be displayed simultaneously in order to convey spatial relationships. Unique challenges in information and interaction design have to be solved in order to keep the visualization sufficiently complete and uncluttered at the same time. The visualization method presented in this paper addresses these issues by using a hybrid combination of polygonal rendering of brain structures and direct volume rendering of activation data. Advanced rendering techniques including illustrative display styles and ambient occlusion calculations enhance the clarity of the visual output. The presented rendering pipeline produces real-time frame rates and offers a high degree of configurability. Newly designed interaction and measurement tools are provided, which enable the user to explore the data at large, but also to inspect specific features closely. We demonstrate the system in the context of a cognitive neurosciences dataset. An initial informal evaluation shows that our visualization method is deemed useful for clinical research. [source] In vivo proton spectroscopy without solvent suppressionCONCEPTS IN MAGNETIC RESONANCE, Issue 4 2001David B. Clayton Abstract In 1H MR spectroscopy of the human brain, it is common practice to suppress the solvent signal prior to acquisition. This reduces the large dynamic range which is otherwise required of the MR receiver and digitizer in order to detect the dilute metabolite resonances in the presence of the much larger water signal. However, complete solvent suppression is not always obtainable, particularly over large volumes and in superficial regions containing large susceptibility gradients. In this work, it demonstrated that modern commercial MR scanners possess the dynamic range necessary to adequately resolve the 1H metabolites in unsuppressed spectra. Moreover, a postacquisition method is presented which can completely remove the intact water signal and accurately quantitate the metabolite peaks. Preserving the water signal in in vivo spectroscopy has several useful benefits, such as providing a high signal-to-noise ratio internal concentration, frequency, and line shape reference. Comparison is made between suppressed and unsuppressed spectra from both a phantom and the human brain acquired at 4 T. © 2001 John Wiley & Sons, Inc. Concepts Magn Reson 13: 260,275, 2001 [source] Augmenting LZ-77 with authentication and integrity assurance capabilitiesCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 11 2004Mikhail J. Atallah Abstract The formidable dissemination capability allowed by the current network technology makes it increasingly important to devise new methods to ensure authenticity and integrity. Nowadays it is common practice to distribute documents in compressed form. In this paper, we propose a simple variation on the classic LZ-77 algorithm that allows one to hide, within the compressed document, enough information to warrant its authenticity and integrity. The design is based on the unpredictability of a certain class of pseudo-random number generators, in such a way that the hidden data cannot be retrieved in a reasonable amount of time by an attacker (unless the secret bit-string key is known). Since it can still be decompressed by the original LZ-77 algorithm, the embedding is completely ,transparent' and backward-compatible, making it possible to deploy it without disrupting service. Experiments show that the degradation in compression due to the embedding is almost negligible. Copyright © 2004 John Wiley & Sons, Ltd. [source] Corporate social responsibility in Asian supply chainsCORPORATE SOCIAL RESPONSIBILITY AND ENVIRONMENTAL MANAGEMENT, Issue 3 2006Richard Welford Abstract This research provides an overview of CSR practices in Asia, evaluates the usefulness of codes of conduct, reviews the benefits of CSR in supply chains and reviews obstacles for companies wishing to adopt good CSR practices. In order to achieve this, interviews were undertaken with CSR managers, factory managers and other experts, conducted in confidence and anonymously. Codes of conduct and associated inspections and audits are common practice but in most cases flawed. Labour issues and the rights of workers are generally seen as the most important aspect of CSR in the region. Benefits of CSR include risk reduction, staff recruitment and retention, cost savings and building good relationships with stakeholders. Obstacles include a lack of resources and skills, a lack of awareness of stakeholders' demands and inefficient production techniques. It is noted that larger firms are more able to overcome such obstacles, with clear adverse implications for smaller companies. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment. [source] Infants' long-term memory for a serial list: Recognition and reactivationDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2001Michelle Gulya Abstract Serial lists contain information about item identity and item order. Using a task designed for nonverbal animals, we previously found that 3- and 6-month-olds exhibited a primacy effect after 24 hr, remembering both item identity and item order. Presently, we examined their memory of list information after longer delays. In Experiment 1, the serial-position curve reverted to a U-shape after 1 week at both ages, revealing that the common practice of attributing primacy and recency effects to long- and short-term memory, respectively, is flawed. In Experiment 2, a precuing procedure confirmed that 6-month-olds' memory still contained order information after 1 week, but 3-month-olds' reactivated memory contained none. Experiments 3A and 3B confirmed that increasing the complexity of information that was learned shortened the delay after which it could be retrieved. Testing infants after delays longer than have previously been used with animals or human adults sheds new light on an old phenomenon. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 38: 174,185, 2001 [source] There is No Puzzle about ChangeDIALECTICA, Issue 1 2009Pablo Rychter This paper argues against the common practice of presenting perdurantism, endurantism, and other views about persistence and time as solutions to an alleged puzzle about change. Various recent attempts to generate a puzzle about change are examined and found unsuccessful. This does not mean, however, that the relevant views about persistence and time are not well motivated, but rather that their interest and purpose is independent of their suitability for solving the alleged puzzle. [source] Trends in morphine prescriptions, illicit morphine use and associated harms among regular injecting drug users in AustraliaDRUG AND ALCOHOL REVIEW, Issue 5 2006LOUISA DEGENHARDT Abstract This paper examines population trends in morphine prescriptions in Australia, and contrasts them with findings from annual surveys with regular injecting drug users (IDU). Data on morphine prescriptions from 1995 to 2003 were obtained from the Drug Monitoring System (DRUMS) run by the Australian Government Department of Health and Ageing. Data collected from regular IDU as part of the Australian Illicit Drug Reporting System (IDRS) were analysed (2001,2004). The rate of morphine prescription per person aged 15,54 years increased by 89% across Australia between 1995 and 2003 (from 46.3 to 85.9 mg per person). Almost half (46%) of IDU surveyed in 2004 reported illicit morphine use, with the highest rates in jurisdictions where heroin was less available. Recent morphine injectors were significantly more likely to be male, unemployed, out of treatment and homeless in comparison to IDU who had not injected morphine. They were also more likely to have injected other pharmaceutical drugs and to report injection related problems. Among those who had injected morphine recently, the most commonly reported injecting harms were morphine dependence (38%), difficulty finding veins into which to inject (36%) and scarring or bruising (27%). Morphine use and injection is a common practice among regular IDU in Australia. In some cases, morphine may be a substitute for illicit heroin; in others, it may be being used to treat heroin dependence where other pharmacotherapies, such as methadone and buprenorphine, are perceived as being unavailable or undesirable by IDU. Morphine injection appears to be associated with polydrug use, and with it, a range of problems related to drug injection. Further research is required to monitor and reduce morphine diversion and related harms by such polydrug injectors. [source] Reduced-complexity flow routing models for sinuous single-thread channels: intercomparison with a physically-based shallow-water equation modelEARTH SURFACE PROCESSES AND LANDFORMS, Issue 5 2009A. P. Nicholas Abstract Reduced-complexity models of fluvial processes use simple rules that neglect much of the underlying governing physics. This approach is justified by the potential to use these models to investigate long-term and/or fundamental river behaviour. However, little attention has been given to the validity or realism of reduced-complexity process parameterizations, despite the fact that the assumptions inherent in these approaches may limit the potential for elucidating the behaviour of natural rivers. This study presents two new reduced-complexity flow routing schemes developed specifically for application in single-thread rivers. Output from both schemes is compared with that from a more sophisticated model that solves the depth-averaged shallow water equations. This comparison provides the first demonstration of the potential for deriving realistic predictions of in-channel flow depth, unit discharge, energy slope and unit stream power using simple flow routing schemes. It also highlights the inadequacy of modelling unit stream power, shear stress or sediment transport capacity as a function of local bed slope, as has been common practice in a number of previous reduced-complexity models. Copyright © 2009 John Wiley & Sons, Ltd. [source] Pricing Loans Using Default ProbabilitiesECONOMIC NOTES, Issue 2 2003Stuart M. Turnbull This paper examines the pricing of loans using the term structure of the probability of default over the life of the loan. We describe two methodologies for pricing loans. The first methodology uses the term structure of credit spreads to price a loan, after adjusting for the difference in recovery rates between bonds and loans. In loan origination, it is common practice to estimate the probability of default for a loan over a specified time horizon and the loss given default. The second methodology shows how to incorporate this information into the arbitrage free pricing of a loan. We also show how to derive an estimate of the credit spread due to liquidity risk. For both methodologies, we show how to calculate a break,even credit spread, taking into account the fee structure of a loan and the costs associated with the term structure of marginal economic capital. The break,even spread is the minimum spread for the loan to be EVA neutral in a multi,period setting. (J.E.L.: G12, G33). [source] Wrinkles in the rare biosphere: pyrosequencing errors can lead to artificial inflation of diversity estimatesENVIRONMENTAL MICROBIOLOGY, Issue 1 2010Victor Kunin Summary Massively parallel pyrosequencing of the small subunit (16S) ribosomal RNA gene has revealed that the extent of rare microbial populations in several environments, the ,rare biosphere', is orders of magnitude higher than previously thought. One important caveat with this method is that sequencing error could artificially inflate diversity estimates. Although the per-base error of 16S rDNA amplicon pyrosequencing has been shown to be as good as or lower than Sanger sequencing, no direct assessments of pyrosequencing errors on diversity estimates have been reported. Using only Escherichia coli MG1655 as a reference template, we find that 16S rDNA diversity is grossly overestimated unless relatively stringent read quality filtering and low clustering thresholds are applied. In particular, the common practice of removing reads with unresolved bases and anomalous read lengths is insufficient to ensure accurate estimates of microbial diversity. Furthermore, common and reproducible homopolymer length errors can result in relatively abundant spurious phylotypes further confounding data interpretation. We suggest that stringent quality-based trimming of 16S pyrotags and clustering thresholds no greater than 97% identity should be used to avoid overestimates of the rare biosphere. [source] Measured partitioning coefficients for parent and alkyl polycyclic aromatic hydrocarbons in 114 historically contaminated sediments: Part 1.ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2006KOC values Abstract Polycyclic aromatic hydrocarbon (PAH) partitioning coefficients between sediment organic carbon and water (KOC) values were determined using 114 historically contaminated and background sediments collected from eight different rural and urban waterways in the northeastern United States. More than 2,100 individual KC values were measured in quadruplicate for PAHs ranging from two to six rings, along with the first reported KOC values for alkyl PAHs included in the U.S. Environmental Protection Agency's (U.S. EPA) sediment narcosis model for the prediction of PAH toxicity to benthic organisms. Sediment PAH concentrations ranged from 0.2 to 8,600 ,g/g (U.S. EPA 16 parent PAHs), but no observable trends in KOC values with concentration were observed for any of the individual PAHs. Literature KOC values that are commonly used for environmental modeling are similar to the lowest measured values for a particular PAH, with actual measured values typically ranging up to two orders of magnitude higher for both background and contaminated sediments. For example, the median log KOC values we determined for naphthalene, pyrene, and benzo[a]pyrene were 4.3, 5.8, and 6.7, respectively, compared to typical literature KOC values for the same PAHs of 2.9, 4.8, and 5.8, respectively. Our results clearly demonstrate that the common practice of using PAH KOC values derived from spiked sediments and modeled values based on n -octanol,water coefficients can greatly overestimate the actual partitioning of PAHs into water from field sediments. [source] Caecal impactions managed surgically by typhlotomy in 10 cases (1988,1998)EQUINE VETERINARY JOURNAL, Issue S32 2000C. T. ROBERTS Summary Surgical management of caecal impactions has included several different procedures suggested over the years. Complete bypass of the caecum through an ileocolic or jejunocolic anastomosis has become common practice for first time caecal impaction management, especially when dysfunction is suspected. In our practice, however, caecal impactions have been managed surgically by typhlotomy alone and of the 10 cases (July 1988-June 1998), 9 underwent surgery for first time caecal impactions, received a typhlotomy, and had survived an average of 43 months at time of case review. At the time of surgery, all were considered to have a dysfunctional caecum. All horses received routine postoperative care with the addition of anthelmintics as recovery of Anoplocephala perfoliata occurred in several cases. Typhlotomy should be considered an acceptable technique for surgical management of first time caecal impactions. Postoperative pyrantel pamoate and larvicidal anthelmintics should also be considered. [source] A currency index global capital asset pricing modelEUROPEAN FINANCIAL MANAGEMENT, Issue 1 2000Thomas J. O'Brien The application of an international capital asset pricing relationship with two factors, the global market portfolio and a currency index, is described and illustrated. The model and illustration help demonstrate a problem with the common practice of adjusting an asset's expected rate of return across currencies via nominal riskless interest rate differentials. [source] Do cytogenetic abnormalities precede morphologic abnormalities in a developing malignant condition?EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 2 2007Jill K. Northup Abstract Cytogenetic evaluation of bone marrow and neoplastic tissues plays a critical role in determining patient management and prognosis. Here, we highlight two cases in which the cytogenetic studies challenge the common practice of using hematologic and morphologic changes as key factors in malignant disease management. The first case is that of a lymph node sample from a 40-yr-old non-Hodgkin's lymphoma (NHL) patient sent for determination of disease progress. Hematologic studies showed no evidence of transformation to high-grade NHL (>15% blasts with rare mitotic figures). Cytogenetic studies of lymph node showed multiple clonal abnormalities, most notably a der(18) from a t(14;18) which is associated with high-grade NHL. After two cycles of chemotherapy with fludarabine, the patient did not show any clinical response, suggesting possible progression to high-grade lymphoma. The second case is of a patient with a history of human immunodeficiency virus and blastic natural killer leukemia/lymphoma. Hematologic studies of ascitic fluid classified the patient as having pleural effusion lymphoma whereas bone marrow analysis showed no malignancy. Bone marrow cytogenetic studies showed multiple clonal abnormalities including a t(8;14), which is commonly associated with Burkitt's lymphoma (BL). To our knowledge, this is the first case wherein a morphologically normal bone marrow showed presence of clonal abnormalities consistent with BL or Pleural effusion lymphoma. After two cycles of CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) chemotherapy, the patient's general condition and ascitis improved and she was discharged. These studies clearly demonstrate that genetic changes often precede morphologic changes in a developing malignant condition. Therefore, the critical information needed for care of patients with malignant disorders may be incomplete or inaccurate if cytogenetic evaluation is overlooked. [source] A new space-vector transformation for four-conductor systemsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 3 2000A. Ferrero Linear transformations are often employed in the study of three-phase systems, since they allow for simplifying the equations describing the system behaviour. Among them, the Fortescue, Clarke and Park transformations are very widely employed. In particular, the last one leads to the formulation of the Space-Vector theory, that is currently employed in the fields of AC machine theory, power definitions and active filtering. The greatest limitation in the use of these transformations is that they are restricted to systems with only three conductors. However, four-conductor systems are often present in the common practice of the electric systems and the application of the Space- Vector theory to such systems is not as straightforward as in the case of the three-conductor systems: a zero-sequence quantity must be considered separately. This paper proposes a linear transformation that extends the properties of the Space- Vector theory to four-conductor systems, and includes the Park transformation as a special case. The mathematical derivation of this new transformation is reported, and its application is discussed by means of some examples. [source] The use of probiotics in shrimp aquacultureFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2006Ali Farzanfar Abstract Shrimp aquaculture, as well as other industries, constantly requires new techniques in order to increase production yield. Modern technologies and other sciences such as biotechnology and microbiology are important tools that could lead to a higher quality and greater quantity of products. Feeding and new practices in farming usually play an important role in aquaculture, and the addition of various additives to a balanced feed formula to achieve better growth is a common practice of many fish and shrimp feed manufacturers and farmers. Probiotics, as ,bio-friendly agents' such as lactic acid bacteria and Bacillus spp., can be introduced into the culture environment to control and compete with pathogenic bacteria as well as to promote the growth of the cultured organisms. In addition, probiotics are nonpathogenic and nontoxic microorganisms without undesirable side-effects when administered to aquatic organisms. These strains of bacteria have many other positive effects, which are described in this article. [source] River restoration, habitat heterogeneity and biodiversity: a failure of theory or practice?FRESHWATER BIOLOGY, Issue 2010MARGARET A. PALMER Summary 1. Stream ecosystems are increasingly impacted by multiple stressors that lead to a loss of sensitive species and an overall reduction in diversity. A dominant paradigm in ecological restoration is that increasing habitat heterogeneity (HH) promotes restoration of biodiversity. This paradigm is reflected in stream restoration projects through the common practice of re-configuring channels to add meanders and adding physical structures such as boulders and artificial riffles to restore biodiversity by enhancing structural heterogeneity. 2. To evaluate the validity of this paradigm, we completed an extensive evaluation of published studies that have quantitatively examined the reach-scale response of invertebrate species richness to restoration actions that increased channel complexity/HH. We also evaluated studies that used manipulative or correlative approaches to test for a relationship between physical heterogeneity and invertebrate diversity in streams that were not in need of restoration. 3. We found habitat and macroinvertebrate data for 78 independent stream or river restoration projects described by 18 different author groups in which invertebrate taxa richness data in response to the restoration treatment were available. Most projects were successful in enhancing physical HH; however, only two showed statistically significant increases in biodiversity rendering them more similar to reference reaches or sites. 4. Studies manipulating structural complexity in otherwise healthy streams were generally small in scale and less than half showed a significant positive relationship with invertebrate diversity. Only one-third of the studies that attempted to correlate biodiversity to existing levels of in-stream heterogeneity found a positive relationship. 5. Across all the studies we evaluated, there is no evidence that HH was the primary factor controlling stream invertebrate diversity, particularly in a restoration context. The findings indicate that physical heterogeneity should not be the driving force in selecting restoration approaches for most degraded waterways. Evidence suggests that much more must be done to restore streams impacted by multiple stressors than simply re-configuring channels and enhancing structural complexity with meanders, boulders, wood, or other structures. 6. Thematic implications: as integrators of all activities on the land, streams are sensitive to a host of stressors including impacts from urbanisation, agriculture, deforestation, invasive species, flow regulation, water extractions and mining. The impacts of these individually or in combination typically lead to a decrease in biodiversity because of reduced water quality, biologically unsuitable flow regimes, dispersal barriers, altered inputs of organic matter or sunlight, degraded habitat, etc. Despite the complexity of these stressors, a large number of stream restoration projects focus primarily on physical channel characteristics. We show that this is not a wise investment if ecological recovery is the goal. Managers should critically diagnose the stressors impacting an impaired stream and invest resources first in repairing those problems most likely to limit restoration. [source] Timing of predation by rainbow trout controls Daphnia demography and the trophic status of a Minnesota lakeFRESHWATER BIOLOGY, Issue 6 2005LEIF K. HEMBRE Summary 1. Stocking of lakes with rainbow trout is a common practice that presents a potential conflict for lake managers who must balance the interests of anglers with those concerned that zooplanktivory by trout may trigger a trophic cascade and result in decreased water clarity. 2. This study examined how the timing of trout stocking (autumn versus spring) in a Minnesota (U.S.A.) lake affected (i) the population dynamics of their zooplankton food supply (Daphnia pulicaria), (ii) phytoplankton biomass and water clarity and (iii) trout survival. Sizes of both Daphnia and trout populations were estimated acoustically with high-frequency (192 kHz) sonar. 3. Daphnia were nearly eliminated from the lake during winters after trout were stocked in autumn. In both of these years (1996 and 1997), the Daphnia population was small in the spring, and grew during the summer and into the autumn as the trout population diminished. 4. The lake was then stocked in spring for 2 years (1998 and 1999). This fisheries manipulation alleviated predation over the winter, but increased predation on D. pulicaria during the spring, summer and autumn. However, the high mortality caused by the spring-stocked trout was offset by even higher rates of reproduction by the relatively large populations of fecund Daphnia that survived the winter in 1998 and 1999. 5. Grazing by these dense populations of Daphnia produced clear-water phases during May and June that were inhibited in autumn stocking years. In addition, the large Daphnia populations present during the spring and early summer of 1998 and 1999 provided abundant forage for trout. 6. This fisheries manipulation achieved seemingly mutually exclusive management objectives: a robust planktivorous sport fishery, and clear water for other forms of recreation. [source] Which parameters differ in very old patients with chronic atrial fibrillation treated by anticoagulant or aspirin?FUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 5 2008Antithrombotic treatment of atrial fibrillation in the elderly Abstract The objective was to determine the main parameters taken into account for the decision of antithrombotic treatment of atrial fibrillation (AF) by vitamin K antagonist or aspirin. This was a prospective clinical study of four clinical services of geriatric medicine. Two hundred and nine inpatients, 84.7 ± 7 years (women 60.8%), with chronic AF were included. The patients were distributed into two groups (anticoagulant or aspirin) according to medical decision. All the decision criteria for treatment were recorded: cardiopathy, conditions of life, clinical examination (nutrition and autonomy, mini-mental state examination (MMSE), walking evaluation, comorbidity), subjective evaluation of risk of falls and glomerular filtration rate. The thromboembolic risk and the bleeding risk, evaluated subjectively for each patient, were compared with two scores of thrombo-embolic risk and bleeding risk. The evolution of the patients was recorded after 3 months. Student's t -test and chi-squared tests were used for statistical analysis. One hundred and two patients (48.8%) received anticoagulant and 107 patients received aspirin. Patients in the aspirin group were significantly older (86.5 ± 6.5 vs. 82.9 ± 7.1 years), with more frequent social isolation, higher systolic blood pressure, and had more important subjective bleeding risk and risk of falls. Patients in the anticoagulant group had significantly more valvulopathies and a more important subjective thromboembolic risk. Thrombo-phlebitis antecedents, dementia, denutrition and walking alterations were only slightly more frequent in patients in the aspirin group. Physicians underestimated thromboembolic risk (one-third of patients) and they overestimated bleeding risk (half of the patients). After 3 months, the two groups did not significantly differ for death, bleeding or ischaemic events. In common practice, the decision of antithrombotic treatment for AF should take into account not only cardiovascular but also geriatric criteria. [source] Relationship uncertainty linkage statistics (RULS): affected relative pair statistics that model relationship uncertaintyGENETIC EPIDEMIOLOGY, Issue 4 2008Amrita Ray Abstract Linkage analysis programs invariably assume that the stated familial relationships are correct. Thus, it is common practice to resolve relationship errors by either discarding individuals with erroneous relationships or using an inferred alternative pedigree structure. These approaches are less than ideal because discarding data is wasteful and using inferred data can be statistically unsound. We have developed two linkage statistics that model relationship uncertainty by weighting over the possible true relationships. Simulations of data containing relationship errors were used to assess our statistics and compare them to the maximum-likelihood statistic (MLS) and the Sall non-parametric LOD score using true and discarded (where problematic individuals with erroneous relationships are discarded from the pedigree) structures. We simulated both small pedigree (SP) and large pedigree (LP) data sets typed genome-wide. Both data sets have several underlying true relationships; SP has one apparent relationship,full sibling,and LP has several different apparent relationship types. The results show that for both SP and LP, our relationship uncertainty linkage statistics (RULS) have power nearly as high as the MLS and Sall using the true structure. Also, the RULS have greater power to detect linkage than the MLS and Sall using the discarded structure. For example, for the SP data set and a dominant disease model, both the RULS had power of about 93%, while Sall and MLS have 90% and 83% power on the discarded structure. Thus, our RULS provide a statistically sound and powerful approach to the commonly encountered problem of relationship errors. Genet. Epidemiol. © 2008 Wiley-Liss, Inc. [source] Relevance of the genes for bone mass variation to susceptibility to osteoporotic fractures and its implications to gene search for complex human diseasesGENETIC EPIDEMIOLOGY, Issue 1 2002Hong-Wen Deng Abstract We investigate the relevance of the genetic determination of bone mineral density (BMD) variation to that of differential risk to osteoporotic fractures (OF). The high heritability (h2) of BMD and the significant phenotypic correlations between high BMD and low risk to OF are well known. Little is reported on h2 for OF. Extensive molecular genetic studies aimed at uncovering genes for differential risks to OF have focussed on BMD as a surrogate phenotype. However, the relevance of the genetic determination of BMD to that of OF is unknown. This relevance can be characterized by genetic correlation between BMD and OF. For 50 Caucasian pedigrees, we estimated that h2 at the hip is 0.65 (P < 0.0001) for BMD and 0.53 (P < 0.05) for OF; however, the genetic correlation between BMD and OF is nonsignificant (P > 0.45) and less than 1% of additive genetic variance is shared between them. Hence, most genes found important for BMD may not be relevant to OF at the hip. The phenotypic correlation between high BMD and low risk to OF at the hip (approximately ,0.30) is largely due to an environmental correlation (,E = ,0.73, P < 0.0001). The search for genes for OF should start with a significant h2 for OF and should include risk factors (besides BMD) that are genetically correlated with OF. All genes found important for various risk factors must be tested for their relevance to OF. Ideally, employing OF per se as a direct phenotype for gene hunting and testing can ensure the importance and direct relevance of the genes found for the risk of OF. This study may have significant implications for the common practice of gene search for complex diseases through underlying risk factors (usually quantitative traits). Genet. Epidemiol. 22:12,25, 2002. © 2002 Wiley-Liss, Inc. [source] A damage mechanics model for power-law creep and earthquake aftershock and foreshock sequencesGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2000Ian G. Main It is common practice to refer to three independent stages of creep under static loading conditions in the laboratory: namely transient, steady-state, and accelerating. Here we suggest a simple damage mechanics model for the apparently trimodal behaviour of the strain and event rate dependence, by invoking two local mechanisms of positive and negative feedback applied to constitutive rules for time-dependent subcritical crack growth. In both phases, the individual constitutive rule for measured strain , takes the form ,(t),=,,0,[1,+,t/m,]m, where , is the ratio of initial crack length to rupture velocity. For a local hardening mechanism (negative feedback), we find that transient creep dominates, with 0,<,m,<,1. Crack growth in this stage is stable and decelerating. For a local softening mechanism (positive feedback), m,<,0, and crack growth is unstable and accelerating. In this case a quasi-static instability criterion , , , can be defined at a finite failure time, resulting in the localization of damage and the formation of a throughgoing fracture. In the hybrid model, transient creep dominates in the early stages of damage and accelerating creep in the latter stages. At intermediate times the linear superposition of the two mechanisms spontaneously produces an apparent steady-state phase of relatively constant strain rate, with a power-law rheology, as observed in laboratory creep test data. The predicted acoustic emission event rates in the transient and accelerating phases are identical to the modified Omori laws for aftershocks and foreshocks, respectively, and provide a physical meaning for the empirical constants measured. At intermediate times, the event rate tends to a relatively constant background rate. The requirement for a finite event rate at the time of the main shock can be satisfied by modifying the instability criterion to having a finite crack velocity at the dynamic failure time, dx/dt , VR,, where VR is the dynamic rupture velocity. The same hybrid model can be modified to account for dynamic loading (constant stress rate) boundary conditions, and predicts the observed loading rate dependence of the breaking strength. The resulting scaling exponents imply systematically more non-linear behaviour for dynamic loading. [source] Analytical Studies on the Impact of Land Reclamation on Ground Water FlowGROUND WATER, Issue 6 2001Jiu J. Jiao Land reclamation has been a common practice to produce valuable land in coastal areas. The impact of land reclamation on coastal environment and marine ecology is well recognized and widely studied. It has not been recognized yet that reclamation may change the regional ground water regime, which may in turn modify the coastal environment, flooding pattern, and stability of slopes and foundations. This paper represents the first attempt to examine quantitatively the effect of reclamation on ground water levels. Analytical solutions are developed to study the ground water change in response to reclamation based on two hypothetical models. In the first model, the ground water flow regime changes only in the hillside around the reclamation areas. In the second model, the ground water regime changes in the entire hill. Both models assume that the ground water flow is in a steady state and satisfies the Dupuit assumptions. Hypothetical examples are used to demonstrate how the ground water level, ground water divide and ground water submarine discharge will change with the scale and hydraulic conductivity of the reclamation materials. The results show that the change of ground water regime depends mainly on the length of the reclaimed area and the values of hydraulic conductivity of the reclaimed materials. It is also seen that the reclamation may impact not only the ground water regime near the coast areas around the reclamation site, but also that in the coast areas opposite the reclamation area. A reclamation site near Tseung Kwan O in the New Territories in Hong Kong, China, is used as a case study to discuss the possible modification of the ground water system caused by reclamation. [source] Numerical Modeling of Unsaturated Flow in Wastewater Soil Absorption SystemsGROUND WATER MONITORING & REMEDIATION, Issue 2 2003Deborah N. Huntzinger Beach It is common practice in the United States to use wastewater soil absorption systems (WSAS) to treat domestic wastewater. WSAS are expected to provide efficient, long-term removal of wastewater contaminants prior to ground water recharge. Soil clogging at the infiltrative surface of WSAS occurs due to the accumulation of suspended solids, organic matter, and chemical precipitates during continued wastewater infiltration. This clogging zone (CZ) creates an impedance to flow, restricting the hydraulic conductivity and rate of infiltration. A certain degree of clogging may improve the treatment of wastewater by enhancing purification processes, in part because unsaturated flow is induced and residence times are significantly increased. However, if clogging becomes excessive, the wastewater pond height at the infiltrative surface can rise to a level where system failure occurs. The numerical model HYDRUS-2D is used to simulate unsaturated flow within WSAS to better understand the effect of CZs on unsaturated flow behavior and hydraulic retention times in sandy and silty soil. The simulations indicate that sand-based WSAS with mature CZs are characterized by a more widely distributed flow regime and longer hydraulic retention times. The impact of clogging on water flow within the silt is not as substantial. For sand, increasing the hydraulic resistance of the CZ by a factor of three to four requires an increase in the pond height by as much as a factor of five to achieve the same wastewater loading. Because the degree of CZ resistance directly influences the pond height within a system, understanding the influence of the CZ on flow regimes in WSAS is critical in optimizing system design to achieve the desired pollutant-treatment efficiency and to prolong system life. [source] Marginal mandibular nerve injury during neck dissection and its impact on patient perception of appearanceHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 5 2009FRACDS(OMS), FRCS(OMFS), Martin D. Batstone MPhil(Surg) Abstract Background. Neck dissection to remove cervical lymph nodes is common practice in head and neck cancer management. The marginal mandibular nerve may be injured during neck dissection, particularly of level 1. The rate of injury to this nerve is underreported in the literature and its impact on patients is not well defined. Methods. An observational study was undertaken on patients who had undergone neck dissection over a 5-year period. The patients were examined for weakness and given a questionnaire related their perception of their appearance and their function. Results. Sixty-six patients were identified who had undergone 85 neck dissections. The rate of House Brackmann injury was 18% when analyzed by patient and 23% by neck. There were moderate correlations between observed injury and subjective responses to questions relating to ability to smile and weakness of the lower lip. Discussion. The rate of smile asymmetry following neck dissection is relatively high; however, severe injuries to the marginal mandibular nerve are uncommon. © 2009 Wiley Periodicals, Inc. Head Neck, 2009 [source] Routine inclusion of level IV in neck dissection for squamous cell carcinoma of the larynx: Is it justified?HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 4 2004Avi Khafif MD Abstract Background. Dissection of levels II,IV as part of an elective or therapeutic neck dissection is common practice during laryngectomy for laryngeal squamous cell carcinoma (SCC). The necessity of routine dissection at level IV has recently been questioned. The purpose of this study was to find the incidence of level IV metastases in patients with transglottic and supraglottic SCC who underwent neck dissections. Methods. The charts of 71 suitable patients were reviewed. Forty-two had supraglottic primary cancers, and 29 had transglottic primary tumors. Levels II,IV had been removed in them all, and their neck specimens were marked according to the levels of the neck. The surgical specimens were pathologically diagnosed. Results. Of 43 patients who underwent elective lateral neck dissection, the only one (2.3%) with level IV metastases also showed metastases at level II. Nine (32%) of the other 28 patients with clinical adenopathy had level IV metastases. Conclusions. Dissection of level IV as part of a therapeutic neck dissection for supraglottic and transglottic SCC is recommended for patients with clinically enlarged lymph nodes, but its necessity in the absence of detectable adenopathy is challenged. © 2004 Wiley Periodicals, Inc. Head Neck26: 309,312, 2004 [source] Random fields,Union intersection tests for detecting functional connectivity in EEG/MEG imagingHUMAN BRAIN MAPPING, Issue 8 2009Felix Carbonell Abstract Electrophysiological (EEG/MEG) imaging challenges statistics by providing two views of the same underlying spatio-temporal brain activity: a topographic view (EEG/MEG) and tomographic view (EEG/MEG source reconstructions). It is a common practice that statistical parametric mapping (SPM) for these two situations is developed separately. In particular, assessing statistical significance of functional connectivity is a major challenge in these types of studies. This work introduces statistical tests for assessing simultaneously the significance of spatio-temporal correlation structure between ERP/ERF components as well as that of their generating sources. We introduce a greatest root statistic as the multivariate test statistic for detecting functional connectivity between two sets of EEG/MEG measurements at a given time instant. We use some new results in random field theory to solve the multiple comparisons problem resulting from the correlated test statistics at each time instant. In general, our approach using the union-intersection (UI) principle provides a framework for hypothesis testing about any linear combination of sensor data, which allows the analysis of the correlation structure of both topographic and tomographic views. The performance of the proposed method is illustrated with real ERP data obtained from a face recognition experiment. Hum Brain Mapp 2009. © 2009 Wiley-Liss, Inc. [source] Hybrid crossover operators with multiple descendents for real-coded genetic algorithms: Combining neighborhood-based crossover operatorsINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 5 2009Ana M. Sánchez Most real-coded genetic algorithm research has focused on developing effective crossover operators, and as a result, many different types of crossover operators have been proposed. Some forms of crossover operators are more suitable to tackle certain problems than others, even at the different stages of the genetic process in the same problem. For this reason, techniques that combine multiple crossovers, called hybrid crossover operators, have been suggested as alternative schemes to the common practice of applying only one crossover model to all the elements in the population. On the other hand, there are operators with multiple offsprings, more than two descendants from two parents, which present a better behavior than the operators with only two descendants, and achieve a good balance between exploration and exploitation. © 2009 Wiley Periodicals, Inc. [source] Transient anuria requiring nephrostomy after intravesical bacillus Calmette-Guérin instillations for superficial bladder cancerINTERNATIONAL JOURNAL OF UROLOGY, Issue 3 2006TOMOYUKI KANEKO Abstract, A 76-year-old man received intravesical bacillus Calmette-Guérin (BCG) instillations for recurrent superficial bladder cancer. He had undergone right nephroureterectomy for right renal pelvic cancer 9 months previously. He presented with anuria and left hydronephrosis after the fourth instillation, with serum creatinine increasing up to 15.7 mg/dL. Percutaneous nephrostomy was indwelled, and antegrade pyelography showed left vesicoureteral obstruction. There was no sign of recurrent bladder cancer or ureteral cancer. He started spontaneous voiding on day 4 and the nephrostomy was removed on day 8. Most of the side-effects of intravesical BCG therapy are minor, and major adverse reactions are rare. Life-threatening ureteral obstruction would be a rare complication of BCG immunotherapy. Although BCG intravesical instillation after nephroureterectomy is a common practice, special care should be taken of renal function in patients with unilateral kidney during BCG therapy. [source] Barriers to reducing the use of restraints in residential elder care facilitiesJOURNAL OF ADVANCED NURSING, Issue 6 2007Kirsten Moore Abstract Title.,Barriers to reducing the use of restraints in residential elder care facilities Aim., This paper is a report of a study to compare perspectives of staff in residential elder care facilities with those of residents and family members from the same facilities about barriers to reducing the use of physical, chemical and environmental restraints. Background., There is growing research evidence of the potential risk of physical and emotional harm of restraining residents in residential elder care facilities. Despite the potential harms, restraints continue to be a common practice in facilities across Australia. Little research has been undertaken to explore the barriers to reducing the use of restraints. Method., Eighteen individual interviews were conducted with staff, general practitioners and a pharmacist and three focus groups were conducted with a total of 12 residents and 17 family members associated with three residential elder care facilities in Melbourne, Australia in 2004. Findings., The three participating facilities were committed to reducing the use of restraints, although physical, chemical and environmental restraints were used in all three facilities. Barriers to reducing restraint use included fear of resident injury, staff and resource limitations, lack of education and information about alternatives to restraints, environmental constraints, policy and management issues, beliefs and expectations (of staff, family and residents), inadequate review practices and communication barriers. Conclusion., Further education and support for staff and family members in evidence-based practice in relation to resident care and restraint use is needed in at least some residential elder care facilities. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||