bluuebunny/crossref_metadata_2025 huggingface dataset:
Halichoeres sanchezi n. sp., a new wrasse from the Revillagigedo Archipelago of Mexico, tropical eastern Pacific Ocean (Teleostei: Labridae)
Authors: Victor Benjamin C. , Frable Benjamin W. , Ludt William B.
Published: February 2024

A new labrid fish species, Halichoeres sanchezi n. sp., is described from eight specimens collected in the Revillagigedo Archipelago in the tropical eastern Pacific Ocean, off the coast of Mexico. The new species belongs to the Halichoeres melanotis species complex that is found throughout the region, differing by 2.4% in the mtDNA cytochrome c oxidase I sequence from its nearest relative, H. melanotis from Panama, and 2.9% from Halichoeres salmofasciatus from Cocos Island, off Costa Rica. The complex is distinguished from others in the region by having a black spot on the opercular flap and a prominent black area on the caudal fin of males. The juveniles and initial phase of the new species closely resemble those of H. salmofasciatus and Halichoeres malpelo from Malpelo Island of Colombia, differing in having an oblong black spot with a yellow dorsal margin on the mid-dorsal fin of initial-phase adults as well as on juveniles. In contrast, the terminal-phase male color pattern is distinct from other relatives, being vermilion to orangish brown with dark scale outlines, a white patch on the upper abdomen, and a prominent black band covering the posterior caudal peduncle and base of the caudal fin. The new species adds to the list of endemic fish species for the isolated archipelago and is an interesting case of island endemism in the region. The discovery was made during the joint 2022 collecting expedition to the archipelago, which featured a pioneering collaborative approach to an inventory of an island ichthyofauna, specifically including expert underwater photographers systematically documenting specimens in situ, before hand-collection, and then photographed fresh, tissue-sampled, and subsequently vouchered in museum collections.
triact package for R: analyzing the lying behavior of cows from accelerometer data
Authors: Simmler Michael , Brouwers Stijn P.
Published: February 2024

Accelerometers are sensors proven to be useful to analyze the lying behavior of cows. For reasons of algorithm transparency and control, researchers often prefer to use their own data analysis scripts rather than proprietary software. We developed the triact R package that assists animal scientists in analyzing the lying behavior of cows from raw data recorded with a triaxial accelerometer (manufacturer agnostic) attached to a hind leg. In a user-friendly workflow, triact allows the determination of common measures for lying behavior including total lying duration, the number of lying bouts, and the mean duration of lying bouts. Further capabilities are the description of lying laterality and the calculation of proxies for the level of physical activity of the cow. In this publication we describe the functionality of triact and the rationales behind the implemented algorithms. The triact R package is developed as an open-source project and freely available via the CRAN repository.
Comparison of Arterial Stiffness among Prehypertensive and Normotensive Subjects using Photo Pulse Plethysmography: A Pilot Study
Authors: Jeyashree P , Dilara K , Maruthy KN , Dhamodhini KS
Published: February 2024

Introduction: Increased arterial stiffness is a marker of Cardiovascular Disease (CVD), even before clinical signs and symptoms become evident. Hypertension is an established risk factor for CVD. However, recent studies have revealed increased arterial stiffness even among prehypertensives. Photo Pulse Plethysmography (PPG) is an efficient non-invasive, and cost-effective technique to measure arterial stiffness. Studying arterial stiffness using PPG can serve as a surrogate marker of Cardiovascular (CV) risk among prehypertensives. Aim: To compare arterial wall stiffness among prehypertensives and normotensives using PPG. Materials and Methods: This pilot study was conducted at the Sri Ramachandra Institute of Higher Education and Research, Chennai, TamilNadu, India from December 2022 to February 2023. The study population included 10 non diabetic prehypertensives and 10 normotensives, aged between 30- 50 years, with normal lipid profiles. The peripheral pulse was recorded using a PPG module and digitised using AUDACITY software. The Arterial Stiffness Index (SI) was calculated and compared between the two groups. The correlation between anthropometry and arterial SI was also determined. Pearson’s correlation test was used to assess the association using Statistical Package for Social Sciences (SPSS) version 24.0. Results: The SI was found to be higher in prehypertensives compared to normotensives, and this difference was statistically significant (p-value=0.04). SI showed a positive correlation with increasing Blood Pressure (BP) and anthropometric variables (Body Mass Index [BMI] and Waist-Hip Ratio [WHR]; r=0.2 and r=0.15, respectively); however, no significant relationship was observed among these variables. Conclusion: This study concludes that the SI, an important CV risk marker, shows a significant increase in prehypertensive subjects compared to normotensive subjects. However, SI showed mild positive correlation with BP and other anthropometric measurements, though not statistically significant.
Design, Materials and Biomechanics of Orthopaedic Implants: A Narrative Review
Authors: Barreto Melrose , Srivastava Saumya , Mittal Harramb
Published: February 2024

Millions of patients’ lives have been improved by orthopaedic implants. Joint replacement surgery has helped to relieve pain and improve function, while fracture fixation implants promote faster bone healing, resulting in a quicker return to daily activities. The use of more wear-resistant bearing surfaces has increased the longevity of artificial joints. As with any implant, special attention must be paid to the material and design used to create the implants; otherwise, bone fractures or defects may occur, and bone healing may not occur at all. This review highlights the parameters of implant design, the different biomaterials used in implants, and the types of implants, along with their biomechanics. The review provides a brief explanation of the factors involved in designing an implant, the materials used to manufacture it, and the biomechanical principles behind the most common types of implants.
Effect of Organic Sources on Vegetative Growth, Fruit Quality and Yield of Phalsa (Grewia subinaequalis D.C.)
Authors: Sharma Shubham , Ram D. , Tiwari Saurabh , Mishra Divyansh , Pratap Ravi , Kumar Rahul , Maurya Aman Kumar , Sonkar Abhishek , Sachan Dhruvendra Singh
Published: February 2024

Phalsa (Grewia subinaequalis D.C.) is a native plant with nutritionally rich fruits, yet it faces challenges like uneven ripening and small fruit size. This study assessed the efficacy of organic nutrient sources, including Farm Yard Manure (F.Y.M.), Poultry Manure, and Jeevamrit, in improving Phalsa growth and fruit quality. Results revealed that the combination of F.Y.M. and Poultry Manure with Jeevamrit significantly enhanced vegetative growth, increasing shoot length, number of shoots per plant, and inter-nodal length. These benefits are attributed to the nutrient-rich organic sources, which stimulate cell elongation and division, leading to accelerated plant growth. Furthermore, organic sources positively impacted fruit yield, with the highest yield observed under F.Y.M. and Poultry Manure with Jeevamrit treatment. Additionally, there were increased fruiting nodes and extended harvesting periods, contributing to enhanced fruit production. Phalsa fruit size and quality improved substantially due to organic source applications, resulting in larger fruit dimensions and elevated total soluble solids content. Jeevamrit and F.Y.M. facilitated better nutrient transport to developing fruits, enhancing metabolic processes and fruit size. Regarding sugar content, organic sources significantly influenced non-reducing and reducing sugars. F.Y.M. with Jeevamrit yielded higher non-reducing sugar content, while reducing sugar content increased with F.Y.M. and Jeeva Ghanamrit. Phalsa fruit acidity was not significantly affected by organic sources, but there was a non-significant increase in ascorbic acid content under various combination treatments. Economically, the benefit-cost ratio was most favourable with F.Y.M. and Poultry Manure combined with Jeevamrit, showcasing the economic viability of these organic nutrient sources in Phalsa cultivation. In conclusion, this study demonstrates the positive impact of organic nutrient sources, particularly F.Y.M., Poultry Manure, and Jeevamrit, on Phalsa plant growth, fruit yield, and fruit quality. These findings provide valuable insights into sustainable and organic methods for enhancing Phalsa cultivation, potentially leading to increased production and improved fruit quality in this indigenous crop. Further research should explore the applicability of these organic sources in different crops and regions.
Policy‐related issues and recommendations
Authors: Leslie David W. , Janson Natasha , Conley Valerie Martin
Published: April 2006

Those who address questions about phased retirement policies should see them in a larger context of needs for flexibility in the terms of faculty employment.
Evaluation of model complexity and space–time resolution on the prediction of long‐term soil salinity dynamics, western San Joaquin Valley, California
Authors: Schoups G. , Hopmans J. W. , Tanji K. K.
Published: April 2006

The numerical simulation of long‐term large‐scale (field to regional) variably saturated subsurface flow and transport remains a computational challenge, even with today's computing power. Therefore, it is appropriate to develop and use simplified models that focus on the main processes operating at the pertinent time and space scales, as long as the error introduced by the simpler model is small relative to the uncertainties associated with the spatial and temporal variation of boundary conditions and parameter values. This study investigates the effects of various model simplifications on the prediction of long‐term soil salinity and salt transport in irrigated soils. Average root‐zone salinity and cumulative annual drainage salt load were predicted for a 10‐year period using a one‐dimensional numerical flow and transport model (i.e. UNSATCHEM) that accounts for solute advection, dispersion and diffusion, and complex salt chemistry. The model uses daily values for rainfall, irrigation, and potential evapotranspiration rates. Model simulations consist of benchmark scenarios for different hypothetical cases that include shallow and deep water tables, different leaching fractions and soil gypsum content, and shallow groundwater salinity, with and without soil chemical reactions. These hypothetical benchmark simulations are compared with the results of various model simplifications that considered (i) annual average boundary conditions, (ii) coarser spatial discretization, and (iii) reducing the complexity of the salt‐soil reaction system. Based on the 10‐year simulation results, we conclude that salt transport modelling does not require daily boundary conditions, a fine spatial resolution, or complex salt chemistry. Instead, if the focus is on long‐term salinity, then a simplified modelling approach can be used, using annually averaged boundary conditions, a coarse spatial discretization, and inclusion of soil chemistry that only accounts for cation exchange and gypsum dissolution–precipitation. We also demonstrate that prediction errors due to these model simplifications may be small, when compared with effects of parameter uncertainty on model predictions. The proposed model simplifications lead to larger time steps and reduced computer simulation times by a factor of 1000. Copyright © 2006 John Wiley & Sons, Ltd.
Influence of flow rate and organic carbon content on benzene transport in a sandy soil
Authors: Kim Song‐Bae , Ha Heon‐Cheol , Choi Nag‐Choul , Kim Dong‐Ju
Published: April 2006

The influence of organic carbon content at various flow rates on the transport of aqueous benzene in a sandy soil was investigated. Column experiments were conducted for a sandy soil with different carbon contents (0%, 0·5%, and 2% by weight) and flow rates (0·25, 0·625, and 1·25 ml min−1) to observe breakthrough curves of KCl and benzene using a step application. Three types of convection–dispersion transport model (equilibrium, reversible two‐site, and reversible–irreversible sorption) were used to determine the appropriate model that best described the observed benzene transport. The modelling results revealed that the reversible–irreversible transport model was suitable for describing the transport and sorption behaviour of benzene in the sandy soil studied. Retardation and irreversible sorption coefficients increased with increasing carbon content, since the increment of carbon content resulted in the enhancement of sorption capacity for benzene. With increasing flow rate, decreased retardation of aqueous benzene was observed due to less reaction time; however, the model parameter for irreversible sorption increased unrealistically. This was attributed to the interference of velocity change on the irreversible sorption coefficient during parameter estimation. In order to avoid this problem, we introduced a Damköhler number (Da1), which took into account the velocity changes in estimating the irreversible sorption coefficient. A reasonable relationship was then found between Da1 and flow rate, which showed a decrease of Da1 with the increase in flow rate. Copyright © 2006 John Wiley & Sons, Ltd.
When does bedload transport begin in steep boulder‐bed streams?
Authors: Aristide Lenzi Mario , Mao Luca , Comiti Francesco
Published: April 2006

The paper presents the results of field measurements of critical conditions for bedload motion conducted in the Rio Cordon, a steep boulder‐bed stream in the Italian Alps, under conditions of high Reynolds numbers and low relative submergence poorly explored before. Two methods have been used to determine threshold of motion: the displacement of marked clasts and the flow competence approach, which uses the largest grain size diameter transported by each flood event.

The high values of $\tau_{\rm {c}i}^{*}$ confirm the great relevance of non‐bedload effective shear stresses in step–pool streams given by the additional form drag associated with this morphology. Relative submergence effects on the dimensionless critical shear stress $\tau_{\rm {c}i}^{*}$ have been quantified by considering the relative submergence ratio Rh/D84, and the major effect of relative size on the mobility of each particle in steep, widely graded bed mixtures has been evaluated. Finally, the dimensionless critical unit discharge $q_{\rm {c}i}^{*}$ has also been adopted in the regression equations as the critical hydraulic parameter, because it may represent an easier parameter to use than the critical shear stress for steep, rough mountain rivers. Copyright © 2006 John Wiley & Sons, Ltd.
Peptide nucleic acid (PNA) — a review
Authors: Shakeel Shabih , Karim Sajjad , Ali Arif
Published: April 2006

Peptide nucleic acid (PNA) is a nucleobase oligomer in which the entire backbone has been replaced by a backbone composed of N‐(2‐aminoethyl)glycine units. In other words, PNA can be regarded as DNA with a neutral peptide backbone instead of a negatively charged sugar–phosphate backbone. It is chemically stable and resistant to hydrolytic (enzymatic) cleavage and thus not expected to be degraded inside a living cell, although its transportation within the cell is difficult. PNA is capable of recognising specific sequences of DNA and RNA obeying the Watson–Crick hydrogen bonding scheme, and the hybrid complexes exhibit extraordinary thermal stability and unique ionic strength effects. It may also recognise duplex homopurine sequences of DNA to which it binds by strand invasion, forming a stable PNA/DNA/PNA triplex with a looped‐out DNA strand. PNA exhibits superior hybridisation characteristics and improved chemical and enzymatic stability relative to nucleic acids, which is why PNA finds major applications in the diagnostic and pharmaceutical fields. Studies indicate that PNA is capable of inhibiting transcription as well as translation, so it can be used as a new tool for antigene and antisense therapy. Owing to its superior properties, PNA could replace DNA as a probe for many investigation purposes. This paper reviews the synthesis of PNA, its important properties making it a new hot tool in the market and its major applications. Copyright © 2006 Society of Chemical Industry
Characterization of the fracture behavior of polyethylene using measured cohesive curves. III. Structure–property relationships
Authors: Ting S.K.M. , Williams J.G. , Ivankovic A.
Published: April 2006

In part I of this article, the deformation and failure mechanisms of different polyethylene grades formed under different rate and constraint conditions were identified. This study attempts to develop a microstructural understanding of the long term behavior of polyethylene by linking it to the measured fracture properties. Examination of the influence of the microstructural properties, particularly the effect of the chain structure and their interrelated nature on the crack growth resistance forms a basis of discussion. The study performed here should provide pipe manufacturers a valuable understanding of the crack growth behavior of polyethylene. POLYM. ENG. SCI., 46:792–798, 2006. © 2006 Society of Plastics Engineers
Effects of ball milling dispersion of nano‐SiOx particles on impact strength and crystallization behavior of nano‐SiOx–poly(phenylene sulfide) nanocomposites
Authors: Lu Dan , Pan Shiwei
Published: April 2006

Ball milling and mixing with strong shear force and strike force were applied to get fine dispersion of nano‐SiOx particles in poly(phenylene sulfide) (PPS) powder. Nano‐SiOx/PPS composites were manufactured by intensive compounding with 3 wt% nano‐SiOx particles. Effects of the ball milling dispersion on crystal behavior and impact strength of nano‐SiOx/PPS nanocomposites were studied. Physical mechanisms of ball milling dispersion were investigated. Evaluations based on both WAXD and DSC indicates that crystallization behavior of nano‐SiOx/heat‐treated PPS (HT‐PPS) nanocomposites was influenced by the ball milling process. Their crystallinity was 25% less while Izod impact strength was 89% better than those of as‐received neat PPS. Increased kinetic energy via ball milling by external work makes nano‐SiOx able to overcome the attraction from itself to prevent agglomeration. Interfacial bonding of two phases between nano‐SiOx and PPS was enhanced by crosslinking in HT‐PPS and reduction in surface tension of interface during ball milling. The bonds allow SiOx to dissipate energy and thus improve PPS impact strength from the addition of nano‐SiOx. POLYM. ENG. SCI., 46:820–825, 2006. © 2006 Society of Plastics Engineers
Influence of processing aids on the uniaxial extensional behavior of metallocene polyethylenes
Authors: Vogel R. , Brünig H. , Häußler L. , Hatzikiriakos S.G.
Published: April 2006

It has been reported in the literature that boron nitride powders with hexagonal crystal structure in combination with fluoroelastomers at small concentrations (typically 500–1000 ppm) can be used as suitable processing aids in melt extrusion processes to overcome flow instabilities such as sharkskin and gross melt fracture. They essentially act as energy dissipaters and suppress the unbound increase of extensional stresses, which are responsible for triggering gross melt fracture. This paper reports on the mechanism by which the presence of a small amount of boron nitride changes the behavior of metallocene polyethylenes in uniaxial elongation. Samples modified with different processing aids were tested in solid and molten state using uniaxial elongation and other rheological tests. The stress–strain behavior is described by the BDEW (Ball–Doi–Edwards–Warner; Ball et al., Polymer, 22, 1010, (1981)) network theory. This theory predicts a reduction of the entanglement density (number of “slip‐links”) in the presence of boron nitride particles that explains the decrease in extensional stresses. Thus, it can be argued that the presence of boron nitride particles dissipates the release of elastic energy at lower extensional stress levels due to the decrease in the entanglement density, thus preventing catastrophic failures such as gross melt fracture. POLYM. ENG. SCI., 46:735–742, 2006. © 2006 Society of Plastics Engineers
Nanostructures and nanocrystalline composite materials—synthesis, stability and phase transformations
Authors: Wilde Gerhard
Published: April 2006

Nanostructured materials offer particular promise for new and potentially very useful products since they can have very different and often superior properties that crucially depend on the atomistic details of interior or exterior interfaces. The nanostructures may be used in a wide range of contexts, most of these are ones in which ensembles of nanostructures are assembled into complex, functional arrangements. As nanostructured materials are structures that are far from the thermodynamic equilibrium and since they have short transport pathways, fast diffusion and rapid transformation kinetics often lead to coarsening and to the deterioration of the microstructure and the associated properties. Ensuring the stability of the nanoscale structures, e.g. by utilizing a composite approach, is therefore a key issue. This approach, however, imposes additional constraints on processing‐related issues as well as on the stability of phases and phase mixtures, and also on the phase transformations within the nanoscale structural units because of the size confinement and the presence of internal heterophase interfaces. While the entire field is far too vast to be addressed in a single overview, an attempt will be made to highlight recent developments concerning advanced synthesis options and phase stability and phase transformation issues of inorganic nanocrystalline composite materials. These issues are to be considered generally for nanostructured systems, i.e. for systems that are characterized by a large specific interface area. Copyright © 2006 John Wiley & Sons, Ltd.
Effects of intermolecular interactions on the controlled assembly of organic monolayers: an STM study
Authors: Yang Yanlian , Deng Ke , Zeng Qingdao , Wang Chen
Published: April 2006

Representative types of intermolecular interactions were seen to affect self‐assembled molecular architectures, as studied by scanning tunneling microscopy (STM) under ambient conditions. As an example, the ππ interaction is attributed to the formation of chiral domains consisting of 4‐octadecylnitrobenzene (ONB). It is further demonstrated that the ONB assembly can serve as a buffer layer to immobilize coronene molecules on large areas of two‐dimensional close‐packed assemblies. Assemblies of 1,4‐dicarboxylic benzoic acid (DBA) and 4,4′‐bipyridine (Bpy) are associated with two different hydrogen‐bonded, two‐dimensional supramolecular networks. The results of theoretical calculations using density functional theory (DFT) are in qualitative agreement with the observed STM images. Copyright © 2006 John Wiley & Sons, Ltd.
Multistable features of boronized interstitial‐pentamers on Si(113) surfaces
Authors: Zhang Zhaohui , Liu Zhenghui , Sumitomo Koji , Zhu Xing
Published: April 2006

On Si(113) surfaces there exists a peculiar type of reconstructing blocks called pentamers, which are stabilized by self‐interstitial atoms at the subsurface. Here, we demonstrate that such interstitial‐pentamers (IP) can be boronized with different numbers of B atoms and therefore behave as differently stable blocks. The multistable features of the blocks are presented by images of scanning tunneling microscopy and investigated by ab initio calculations, which revealed the surface energy as a function of the number of B atoms in an IP and a minimum of the surface energy for three B atoms in each block. Copyright © 2006 John Wiley & Sons, Ltd.
Social Integration and Suicide in South Korea
Authors: Park B.C. Ben , Lester David
Published: April 2006

The increasing suicide rate in South Korea in recent decades was found to be associated with measures of social integration/regulation (birth and divorce rates).
Parametric study of two-dimensional potential structures induced by radio-frequency sheaths coupled with transverse currents in front of the Ion Cyclotron Resonance Heating antenna
Authors: Faudot E. , Heuraux S. , Colas L.
Published: April 2006

For the first time, a two-dimensional (2D) fluid model and an analytical expression for the rectified potential with respect to the transverse polarization current are established and verified by a 2D PIC (particle in cell) code over the validity domain of our model. Then the model is extended to the overall ion cyclotron frequency range used in different heating and current drive scenarios. First, the models demonstrate that these transverse polarization currents add some inertia in the temporal dynamic. Due to the nonlinear behavior of the I-V sheath characteristic, the time average amplitude (dc potential) of the rectified potential structure is increased compared to the time average rf potential. Second, they induce only a slight widening of the potential structure. Such modifications are quantified using a “test map” initially characterized by a Gaussian shape. The map is assumed to remain Gaussian near its summit. The time behavior of the peak can be estimated analytically in the presence of polarization current as a function of its width r0 and amplitude ϕ0 (normalized to local temperature and to a characteristic length for transverse transport). A potential peaking criterion has been built to determine the peaking zone of the dc potential structure induced by the rf field. Computations made for typical parameters of the edge plasma in front of the antenna of the Tokamak Tore Supra show that the dc rectified potential is up to 50% higher than the previous computations neglecting polarization current effects. The weak diffused and high dc potential structures computed can explain the hot spot formation induced by convective cells associated to high energetic ion fluxes on the corners of the Ion Cyclotron Resonance Heating antenna.
Structural activation of Mad2 in the mitotic spindle checkpoint: the two-state Mad2 model versus the Mad2 template model
Authors: Yu Hongtao
Published: April 2006

The inheritance of a normal assortment of chromosomes during each cell division relies on a cell-cycle surveillance system called the mitotic spindle checkpoint. The existence of sister chromatids that do not achieve proper bipolar attachment to the mitotic spindle in a cell activates this checkpoint, which inhibits the ubiquitin ligase activity of the anaphase-promoting complex or cyclosome (APC/C) and delays the onset of anaphase. The mitotic arrest deficiency 2 (Mad2) spindle checkpoint protein inhibits APC/C through binding to its mitotic-specific activator, Cdc20. Binding of Mad2 to Cdc20 involves a large conformational change of Mad2 and requires the Mad1–Mad2 interaction in vivo. Two related but distinct models of Mad1-assisted activation of Mad2, the “two-state Mad2” and the “Mad2 template” models, have been proposed. I review the recent structural, biochemical, and cell biological data on Mad2, discuss the differences between the two models, and propose experiments that test their key principles.
Measuring the extent of linkage disequilibrium in commercial pig populations
Authors: Harmegnies N. , Farnir F. , Davin F. , Buys N. , Georges M. , Coppieters W.
Published: April 2006

To evaluate the extent of linkage disequilibrium in domestic pigs, we genotyped 33 and 44 unrelated individuals from two commercial populations for 29 and five microsatellite markers located on chromosomes 15 and 2 respectively. A high proportion of marker pairs up to 40 cM apart exhibited significant linkage disequilibrium in both populations. Pair‐wise r2 values averaged between 0.15 and 0.50 (depending on chromosome and population) for markers <1 cM apart and declined to values of 0.05 for more distant syntenic markers. Our results suggest that both populations underwent a bottleneck approximately 20 generations ago, which reduced the effective population size from thousands to <200 animals.
Validation of the European Prognostic Index for younger adult patients with acute myeloid leukaemia in first relapse
Authors: Giles Francis , Verstovsek Srdan , Garcia‐Manero Guillermo , Thomas Deborah , Ravandi Farhad , Wierda William , Ferrajoli Alessandra , Kornblau Steve , Jabbour Elias , Shan Jianqin , O'Brien Susan , Albitar Maher , Kantarjian Hagop
Published: April 2006

In order to validate the European Prognostic Index (EPI) for patients 60 years with acute myeloid leukaemia in first relapse, a cohort of 599 such patients, treated between 1980 and 2004 at the MD Anderson Cancer Center, were assessed using this prognostic index. Three risk groups were defined: favourable, 76 patients (13%) [Overall survival (OS), 64% at 1 year, 22% at 5 years]; intermediate, 137 patients (23%) (OS, 38% at 1 year, 12% at 5 years); and poor, 386 patients (64%) (OS, 17% at 1 year 6% at 5 years). The EPI is reproducible and useful.
Hepatotoxicity of antiretroviral drugs in HIV HCV patients with congenital coagulopathies followed at an Haemophilia Unit during a decade
Authors: SAULEDA S. , MARTORELL M. , ESTEBAN J. I. , TURAL C. , RUIZ I. , PUIG L. , ESTEBAN R. , GUARDIA J. , VARGAS V.
Published: April 2006

Summary.  The aim of the study was to assess the incidence and the cumulative probability of cytolytic and cholestatic hepatotoxicity during antiretroviral treatment in a group of HIV HCV haemophiliacs. We evaluated 47 patients that received 246 courses of antiretroviral treatment [98 courses of pre‐highly active antiretroviral therapy (pre‐HAART) and 148 HAART treatments]. Liver function tests were assessed at baseline of each treatment, after 1 month and at least every 4 months thereafter. Cytolytic and cholestatic hepatotoxicity was recorded. Of the 246 treatments, 28 (12.45%) were followed by cytolytic hepatotoxicity and 32 (13%) by cholestatic hepatotoxicity. Cytolytic hepatotoxicity was similar in HAART (16/148; 10.8%) and in pre‐HAART treatment (12/98; 12.2%) and cholestatic hepatotoxicity was more frequent in HAART (29/148; 19.6%) than in pre‐HAART treatment (3/98; 3.1%) (P < 0.001). The actuarial probability of developing cytolytic and cholestatic hepatotoxicity at 10 years of onset of antiretroviral treatments was 39% and 56%, respectively. Most enzyme elevations were asymptomatic, but in eight cases therapy was discontinued or changed and in one case a cirrhotic patient died of progressive liver failure. In HIV HCV haemophiliacs, the cumulative probability of developing hepatotoxicity during follow‐up is high and although in the most cases the toxicity is mild, fatal cases can occur.
The‘Lightspeed’preparation technique evaluated by Swiss clinicians after attending continuing education courses
Authors: BARBAKOW F. , LUTZ F.
Published: April 2006

This survey evaluated acceptance of the Lightspeed canal preparation (LS) technique by Swiss practitioners. The technique was introduced to Switzerland inJune 1994and 10 other continuing education (CE) courses were held at the Zurich Dental School by July 1995. Acceptance was assessed by posting questionnaires to the CE course attendees. Of the 305 questionnaires posted, 177 (58%) were returned. Of the CE participants 80% had used the technique with 60% finding the method easier and 43% finding it quicker than their usual preparation techniques. Of the respondents 58% used the technique on all tooth types and 76% of the LS users had fractured an instrument at least once. Amongst others, fractures were caused by too much pressure (25%), incorrect insertion angles (17%) and by a complicated root morphology (15%). Fractures occurred high up on the instrument shaft (74%) and near the tip (7%). Working lengths were claimed by 62% to be easier to maintain by LS than their usual preparation techniques. Among the respondents 52% obturated LS prepared canals more easily and quickly compared with their usual preparation techniques. Only 10% of LS users would not recommend the technique, but those who would suggested that proper tuition was necessary to minimize the risk of instrument fracture. The LS technique was positively assessed by clinicians who attended the CE courses in Switzerland where endodontics is not accepted as a speciality
The sequence of sediment behaviour during wave‐induced liquefaction
Authors: MUTLU SUMER B. , HATIPOGLU FIGEN , FREDSØE JØRGEN , KAAN SUMER S.
Published: April 2006

This paper presents the results of an experimental investigation of the complete sequence of sediment behaviour beneath progressive waves. The sediment was silty with d50 = 0.060 mm. Two kinds of measurements were carried out: pore‐water pressure measurements (across the sediment depth), and water‐surface elevation measurements. The process of liquefaction/compaction was videotaped from the side simultaneously with the pressure and water‐surface elevation measurements. The video records were then analysed to measure: (i) the time development of the mudline, (ii) the time development of liquefaction and compaction fronts in the sediment and (iii) the characteristics of the orbital motion of the liquefied sediment including the motion of the interface between the water body and the sediment. The ranges of the various quantities in the tests were: wave height, H = 9–17 cm, wave period, T = 1.6 sec, water depth = 42 cm, and the Shields parameter = 0.34–0.59. The experiments reveal that, with the introduction of waves, excess pore pressure builds up, which is followed by liquefaction during which internal waves are experienced at the interface of the water body and the liquefied sediment, the sequence of processes known from a previous investigation. This sequence of processes is followed by dissipation of the accumulated excess pore pressure and compaction of the sediment which is followed by the formation of bed ripples. The present results regarding the dissipation and compaction appear to be in agreement with recent centrifuge wave‐tank experiments. As for the final stage of the sequence of processes (formation of ripples), the ripple steepness (normalized with the angle of repose) for sediment with liquefaction history is found to be the same as that in sediment with no liquefaction history.
Postoperative sleep disturbance in pediatric patients using patient‐controlled devices (PCA)
Authors: KELLY J.J. , DONATH SUSAN , JAMSEN KRIS , CHALKIADIS G.A.
Published: April 2006

Background : Sleep disturbance has not been well quantified in pediatric postoperative management, yet has broad implications in pain management as well as upon the physical and psychological well‐being of the young patient admitted for surgery. We aimed to describe sleep disturbance in this population using patient‐controlled analgesia (PCA) and then identify the predictors of disturbed sleep.

Methods : A retrospective audit and analysis of sleep disturbance in postoperative pediatric patients using PCA devices were performed in a postoperative surgical ward population of a major tertiary referral center. PCA presses were used as a proxy measure of sleep. The description of the sleep disturbance included an unadjusted and adjusted analysis of the proposed predictors of sleep disturbance: age, sex, nature of presentation, operation type, PCA opioid type, presence of background infusion, postoperative night number, and adjuvant medication. All data were entered into an access database developed for the audit and analyzed using stata 8.0.

Results : The first 126 children prescribed PCA devices in the year 2004 were audited. One‐third of patients in the population prescribed PCA experienced sleep disturbance. Observed predictors of sleep disturbance include older children (OR: 0.86, P = 0.001) and those receiving a background infusion (OR: 0.19, P = 0.002).Other predictors were not significant.

Conclusions : Sleep disruption is common in children‐prescribed PCA opioid analgesia. Older children and those receiving a background infusion were observed to experience less sleep. Other proposed predictors were not found to be reliable. Further investigation into the predictors of disturbed sleep in the postoperative patient is warranted.
Within and Beyond Communities of Practice: Making Sense of Learning Through Participation, Identity and Practice*
Authors: Handley Karen , Sturdy Andrew , Fincham Robin , Clark Timothy
Published: April 2006

abstract Situated learning theory offers a radical critique of cognitivist theories of learning, emphasizing the relational aspects of learning within communities of practice in contrast to the individualist assumptions of conventional theories. However, although many researchers have embraced the theoretical strength of situated learning theory, conceptual issues remain undeveloped in the literature. Roberts, for example, argues in this issue that the notion of ‘communities of practice’– a core concept in situated learning theory – is itself problematic. To complement her discussion, this paper explores the communities of practice concept from several perspectives. Firstly, we consider the perspective of the individual learner, and examine the processes which constitute ‘situated learning’. Secondly, we consider the broader socio‐cultural context in which communities of practice are embedded. We argue that the cultural richness of this broader context generates a fluidity and heterogeneity within and beyond communities. Finally, we argue that it is sometimes difficult to distinguish conceptually between the terms ‘participation’ and ‘practice’ because of occasional duplication of meaning. We propose, instead, a refinement of the definition to allow for greater conceptual clarity.
The mechanism of emergenesis
Authors: Lykken D. T.
Published: April 2006

Since each individual produced by the sexual process contains a unique set of genes, very exceptional combinations of genes are unlikely to appear twice even within the same family.

E. O. Wilson (1978)

The intraclass correlations of monozygotic twins who were separated in infancy and reared apart (MZA twins) provide estimates of trait heritability, and the Minnesota Study of Twins Reared Apart [MISTRA: Bouchard et al. (1990), The sources of human psychological differences: the Minnesota study of twins reared apart, Science 250, 223–228] has demonstrated that MZA pairs are as similar in most respects as MZ pairs reared together. Some polygenic traits—e.g. stature, IQ, harm avoidance, negative emotionality, interest in sports—are polygenic‐additive, so pairs of relatives resemble one another on the given trait in proportion to their genetic similarity. But the existence and the intensity of other important psychological traits seem to be emergent properties of gene configurations (or configurations of independent and partially genetic traits) that interact multiplicatively rather than additively. Monozygotic (MZ) twins may be strongly correlated on such emergenic traits, while the similarity of dizygotic (DZ) twins, sibs or parent–offspring pairs may be much less than half that of MZ pairs. Some emergenic traits, although strongly genetic, do not appear to run in families. MISTRA has provided at least two examples of traits for which MZA twins are strongly correlated, and DZA pairs correlate near zero, while DZ pairs reared together (DZTs) are about half as similar as MZTs. These findings suggest that even more traits may be emergenic than those already identified. Studies of adoptees reared together (who are perhaps more common than twins reared apart) may help to identify traits that are emergenic, but that also are influenced by a common rearing environment.
Which Factors Are Associated with the Application of Reperfusion Therapy in ST-Elevation Acute Coronary Syndromes?
Authors: Nieuwlaat R. , Lenzen M. , Crijns H.J.G.M. , Prins M.H. , Scholte op Reimer W.J. , Battler A. , Hasdai D. , Danchin N. , Gitt A.K. , Simoons M.L. , Boersma E.
Published: April 2006

Background/Aims:A large proportion of patients with a ST-elevation acute coronary syndrome do not receive reperfusion therapy. In order to contribute to a better understanding of the clinical decision making process, we analyzed which factors are associated with the application of reperfusion therapy. Methods: From the Euro Heart Survey of Acute Coronary Syndromes I, 4,260 patients with ST-elevation acute coronary syndrome were selected for the current analysis, of which 1,539 (36%) patients received fibrinolysis and 904 (21%) primary percutaneous coronary intervention (PCI). The analysis contained 32 variables on demographics, medical history, admission parameters and reperfusion therapy. Results: A short pre-hospital delay, arrival in a hospital with PCI facilities, severe ST-elevation, and participation in a clinical trial were the strongest predictors for receiving reperfusion therapy. Primary PCI was more likely to be performed than fibrinolysis in patients with a long pre-hospital delay, arriving in a hospital with PCI facilities, not participating in a clinical trial, and with at least one previous PCI. Conclusion:Hospital facilities and culture, pre-hospital delay and infarction size play a major role in management decisions regarding reperfusion therapy in ST-elevation acute coronary syndrome. This analysis indicates which factors require special attention when implementing and reviewing the reperfusion guidelines.
Dynamics of Sheared Convective Boundary Layer Entrainment. Part II: Evaluation of Bulk Model Predictions of Entrainment Flux
Authors: Conzemius Robert J. , Fedorovich Evgeni
Published: April 2006

Several bulk model–based entrainment parameterizations for the atmospheric convective boundary layer (CBL) with wind shear are reviewed and tested against large-eddy simulation (LES) data to evaluate their ability to model one of the basic integral parameters of convective entrainment—the entrainment flux ratio. Test results indicate that many of these parameterizations fail to correctly reproduce entrainment flux in the presence of strong shear because they underestimate the dissipation of turbulence kinetic energy (TKE) produced by shear in the entrainment zone. It is also found that surface shear generation of TKE may be neglected in the entrainment parameterization because it is largely balanced by dissipation. However, the surface friction has an indirect effect on the entrainment through the modification of momentum distribution in the mixed layer and regulation of shear across the entrainment zone. Because of this effect, parameterizations that take into account the surface friction velocity but exclude entrainment zone shear may sufficiently describe entrainment when wind shear in the free atmosphere above the CBL is small. In this case, the surface shear acts as a proxy for the entrainment zone shear. Such parameterizations can be most useful if applied in situations where atmospheric data are insufficient for calculating entrainment zone shear. The importance of modeling a Richardson-number-limited, finite-depth entrainment zone is evidenced by the relatively accurate entrainment flux predictions by models that explicitly account for effects of entrainment zone shear, but predictions by these models are often adversely affected by the underestimation of TKE dissipation in the entrainment zone.
Extracting Envelopes of Nonzonally Propagating Rossby Wave Packets
Authors: Zimin Aleksey V. , Szunyogh Istvan , Hunt Brian R. , Ott Edward
Published: April 2006

Previously developed techniques that have been used to extract envelopes of Rossby wave packets are based on the assumption of zonally propagating waves. In this note a method that does not require such an assumption is proposed. The advantages of the new technique, both on analytical and real-world examples, are demonstrated.
A Comparison of Data Assimilation Methods Using a Planetary Geostrophic Model
Authors: Zaron Edward D.
Published: April 2006

Assimilating hydrographic observations into a planetary geostrophic model is posed as a problem in control theory. The cost functional is the sum of weighted model and data residuals. Model errors are assumed to be spatially correlated, and hydrographic station data are assimilated directly. Searches in state space and data space, for minimizing the cost functional, are compared to a direct matrix inversion algorithm in the data space.

State-space methods seek the minimizer of the cost functional by performing a preconditioned search in an N-dimensional space of state or control variables, where N is approximately 650 000 in the present calculations. Data-space methods solve the Euler–Lagrange equations for the extremum of the cost functional by working in an M-dimensional dual space, where M is the number of measurements. The following four solvers are compared: (i) an iterative state-space solver, with a naive diagonal matrix preconditioner; (ii) an iterative state-space solver, with a sophisticated preconditioner based on the inverse of the model’s dynamical operators; (iii) an iterative data-space solver, with no preconditioning; and (iv) a direct, M × M matrix inversion, data-space solver. The best solver is the iterative data-space solver, (iii), which is approximately 10 times faster than the sophisticated preconditioned state-space solver, (ii), and 100 times faster than the direct data-space solver, (iv).
United Kingdom Collaborative Randomized Trial of Neonatal Extracorporeal Membrane Oxygenation: Follow-up to Age 7 Years
Authors: McNally Helena , Bennett Charlotte C. , Elbourne Diana , Field David J. ,   for the UK Collaborative ECMO Trial Group
Published: April 2006

OBJECTIVE. The UK Collaborative ECMO trial provided an opportunity to describe mortality and morbidity associated with a neonatal ECMO policy compared with conventional management. The improved survival in the ECMO group was not offset by an increase in disability at 4 years, but the children were too young to assess educational and other longer-term impacts. The objective of this study was to assess the longer-term impact of these policies at age 7 years.

METHODS. A psychologist assessed 90 of the 100 children available for follow-up without prior knowledge of treatment allocation. The assessments took place at the children's schools within 3 months of their 7th birthdays.

RESULTS. Sixty-eight of 89 (76%) children recorded a cognitive level within the normal range. Learning problems were similar in the 2 groups, and there were notable difficulties with spatial and processing tasks. A higher respiratory morbidity and increased risk of behavioral problems among children treated conventionally persisted. Progressive sensorineural hearing loss was found in both groups.

CONCLUSIONS. The underlying disease processes appear to be the major influence on morbidity at 7 years. The beneficial influence of an ECMO policy is still present at 7 years.
HYBRIDIZATION AND THE EVOLUTION OF PLANTS
Authors: Barber H. N.
Published: April 2006

Polyploidy — both auto‐ and allo — may have dominated the short term evolution of plants because it increases “biochemical versatility” at the primary enzyme level. It actually creates new enzymes with different properties which may extend the range of environments in which normal and successful development may occur.. The new enzymes arise by oligomerisation of related polypeptides produced by related (homoeologous) genes (“hybrid” enzymes).

Further study of polyploids may help us understand more about the control of development of the phenotype. There is evidence that the concentration of different isoenzymes changes with the development of tissues. Whether this denotes a causal connection between differentiation and enzyme production, we do not know. But the presence of isoenzymes generated by polyploidy may have allowed such controls to be made more refined and delicate and, thus, helped in ecological success. The determination of the actual amino‐acid sequences of such enzymes may, in the future, perhaps contribute to a further understanding of the role of enzyme hybridization for biochemical versatility as a factor in evolution.