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Very Short (very + short)
Terms modified by Very Short Selected AbstractsDentists' preferences of anterior tooth proportion,a Web-based studyJOURNAL OF PROSTHODONTICS, Issue 3 2000Stephen F. Rosenstiel BDS Purpose This study aimed to determine dentists' esthetic preferences of the maxillary anterior teeth as influenced by different proportions. The goal was to link choices to demographic data as to the experience, gender, and training of the dentist. Materials and Methods Computer-manipulated images of the 6 maxillary anterior teeth were generated from a single image and assigned to 5 tooth-height groups (very short, short, normal height, tall, and very tall). For each group, 4 images were generated by manipulating the relative proportion of the central incisors, lateral incisors, and canines according to the proportions 62% (or "golden proportion"), 70%, 80%, and "normal" or not further altered. The images were randomly ordered on a web page that contained a form asking for demographic data and fields asking for a ranking of the images. Dentists were asked via e-mail to visit the web page and complete the survey. The responses were tabulated and analyzed with repeated measures logistic regression with the alpha at 0.05. A subset of North American respondents was chosen for further analysis. Results A total of 549 valid responses were received and analyzed from dentists in 38 countries. There were statistically significant differences in all groups for the variables of proportion, group (tooth height), and their interaction. The 80% proportion was judged best for the Very Short and Short groups. Three of the choices were almost equally picked for the Normal Height and Tall groups, and the golden proportion was judged best for the Very Tall group. The variables of year of graduation, gender, professional activity, generalist or specialist, or number of patients were not significantly correlated with the choices for the North American respondents. Conclusions Dentists preferred the 80 percent proportion when viewing short or very short teeth and the golden proportion when viewing very tall teeth. Golden proportion was worst for normal height or shorter teeth and the 80% proportion for tall or very tall teeth. They picked no clear-cut best for normal height or tall teeth, and their choices could not be predicted based on gender, specialist training, experience, or patient load. [source] Lower esophageal palisade vessels and the definition of Barrett's esophagusDISEASES OF THE ESOPHAGUS, Issue 7 2008K. Ogiya SUMMARY., The designated area of the columnar-lined esophagus (CLE) is anatomically defined by the distal limit of the lower esophageal palisade vessels (LEPV) and the term ,Barrett's esophagus' is equally used along with the name CLE in Japan. The aim of this study was to investigate the actual prevalence of CLE based on the Japanese criteria and to evaluate the criteria per se. A total of 42 esophagi consecutively resected at this institute were included. All subjects underwent a surgical resection for squamous cell carcinoma of the esophagus. The position of the LEPV, squamocolumnar junction, the prevalence of CLE and intestinal metaplasia were investigated both pre- and postoperatively. Preoperative endoscopy revealed CLE based on the Japanese criteria in half of all patients. In the resected specimens the distal limit of LEPV was lower than the squamocolumnar junction in 95.2%. In other words, almost all cases had CLE (equivalent to Barrett's mucosa in Japanese criteria). However, most of the CLE areas were very short and their average maximum length was only about 5 mm. In addition, no intestinal metaplasia was observed in any of the CLE cases. Almost all individuals might therefore be diagnosed to have CLE or Barrett's mucosa based on precise endoscopic observations in Japan. The CLE located in a small area, e.g. less than 5 mm, defined according to the LEPV criteria without any other factor concerning typical Barrett's esophagus such as signs of gastroesophageal reflux should therefore be excluded from consideration as a high-risk mucosa. [source] Rapid evolution in introduced species, ,invasive traits' and recipient communities: challenges for predicting invasive potentialDIVERSITY AND DISTRIBUTIONS, Issue 4 2008Kenneth D. Whitney ABSTRACT The damaging effects of invasive organisms have triggered the development of Invasive Species Predictive Schemes (ISPS). These schemes evaluate biological and historical characteristics of species and prioritize those that should be the focus of exclusion, quarantine, and/or control. However, it is not clear how commonly these schemes take microevolutionary considerations into account. We review the recent literature and find that rapid evolutionary changes are common during invasions. These evolutionary changes include rapid adaptation of invaders to new environments, effects of hybridization, and evolution in recipient communities. Strikingly, we document 38 species in which the specific traits commonly associated with invasive potential (e.g. growth rate, dispersal ability, generation time) have themselves undergone evolutionary change following introduction, in some cases over very short (, 10 year) timescales. In contrast, our review of 29 ISPS spanning plant, animal, and microbial taxa shows that the majority (76%) envision invading species and recipient communities as static entities. Those that incorporate evolutionary considerations do so in a limited way. Evolutionary change not only affects the predictive power of these schemes, but also complicates their evaluation. We argue that including the evolutionary potential of species and communities in ISPS is overdue, present several metrics related to evolutionary potential that could be incorporated in ISPS, and provide suggestions for further research on these metrics and their performance. Finally, we argue that the fact of evolutionary change during invasions begs for added caution during risk assessment. [source] Novel coupling Rosenbrock-based algorithms for real-time dynamic substructure testingEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 3 2008O. S. Bursi Abstract Real-time testing with dynamic substructuring is a novel experimental technique capable of assessing the behaviour of structures subjected to dynamic loadings including earthquakes. The technique involves recreating the dynamics of the entire structure by combining an experimental test piece consisting of part of the structure with a numerical model simulating the remainder of the structure. These substructures interact in real time to emulate the behaviour of the entire structure. Time integration is the most versatile method for analysing the general case of linear and non-linear semi-discretized equations of motion. In this paper we propose for substructure testing, L-stable real-time (LSRT) compatible integrators with two and three stages derived from the Rosenbrock methods. These algorithms are unconditionally stable for uncoupled problems and entail a moderate computational cost for real-time performance. They can also effectively deal with stiff problems, i.e. complex emulated structures for which solutions can change on a time scale that is very short compared with the interval of time integration, but where the solution of interest changes on a much longer time scale. Stability conditions of the coupled substructures are analysed by means of the zero-stability approach, and the accuracy of the novel algorithms in the coupled case is assessed in both the unforced and forced conditions. LSRT algorithms are shown to be more competitive than popular Runge,Kutta methods in terms of stability, accuracy and ease of implementation. Numerical simulations and real-time substructure tests are used to demonstrate the favourable properties of the proposed algorithms. Copyright © 2007 John Wiley & Sons, Ltd. [source] Winter survival and oviposition before and after overwintering of a parasitoid wasp, Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae)ENTOMOLOGICAL SCIENCE, Issue 2 2004Takeshi TERAOKA Abstract Winter survival and oviposition before and after overwintering in Ooencyrtus nezarae, an egg parasitoid of phytophagous heteropterans, were examined in Osaka, Japan. Eggs of Riptortus clavatus parasitized by O. nezarae were kept under natural photoperiod and temperature. When honey was supplied, some female adults emerging from early September to late November overwintered. The percentage of overwintering individuals increased as the date of adult emergence advanced. Most female adults supplied with honey and hosts oviposited soon after emergence, then stopped laying eggs. Female adults emerging in mid-October and early November laid eggs and then overwintered. The induction of diapause in the field seems to vary greatly depending on host availability. Without honey, the survival time of female adults was very short, whether host eggs were supplied or not. After overwintering, most females began to lay eggs in early May if host eggs were supplied, and they produced both male and female progeny. In the study area, a legume field in Osaka, parasitization by O. nezarae was observed from early July to November. [source] Characterization in vivo of bilaterally branching pontocerebellar mossy fibre to Golgi cell inputs in the rat cerebellumEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2009Tahl Holtzman Abstract Golgi cells regulate the flow of information from mossy fibres to the cerebellar cortex, through a mix of feedback and feedforward inhibitory actions on granule cells. The aim of the current study was to examine mossy fibre input to Golgi cells, in order to assess their impact on switching Golgi cells into feedforward behaviour. In urethane-anaesthetized rats, extracellular recordings were made from Golgi cells in Crus II (n = 18). Spikes were evoked in all Golgi cells by microstimulation within the contralateral hemispheral cortex, via branches of mossy fibres that terminate in both cerebellar hemispheres. The latencies of these responses were very short, consistent with a monosynaptic mossy fibre contact [average onset latency 2.3 ± 0.1 ms (SEM)]. The same stimuli had no measurable effect on spike responses of nearby Purkinje cells (n = 12). Systematic mapping in the contralateral cerebellar hemisphere (Crus Ib, IIa, IIb and the paramedian lobule) usually revealed one low-intensity stimulus ,hotspot' (12,35 ,A) from which short-latency spikes could be evoked in an individual Golgi cell. Microinjections of red and green retrograde tracers (latex beads, ,50,150 nL injection volume) made at the recording site and the stimulation hotspot resulted in double-labelled neurons within the pontine nuclei. Overall, this suggests that subsets of pontine neurons supply mossy fibres that branch to both hemispheres, some of which directly target Golgi cells. Such an arrangement may provide a common feedforward inhibitory link to temporally couple activity on both sides of the cerebellum during behaviour. [source] Short and Efficient Synthesis of Alkyne-Modified Amino Glycoside Building BlocksEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 17 2009Claudine M. Klemm Abstract In the light of recent progress in RNA biology, the need for molecules that bind to RNA and thus may be suited to manipulating RNA-mediated processes is steadily increasing. We present a very short and efficient synthetic route to alkyne-modified neamine and 2-deoxystreptamine derivatives on a half-gram scale. These derivatives are suitable for constructing a library of potential divalent RNA binders by copper-catalysed 1,3-dipolar cycloaddition to diazides ("click chemistry"). The conjugate dimers thus formed inhibitedDicer-mediated micro-RNA maturation with IC50 values between 0.6 and 15 ,M.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] THE CONDITIONS FOR SPECIATION THROUGH INTRASPECIFIC COMPETITIONEVOLUTION, Issue 11 2006Reinhard Bürger Abstract It has been shown theoretically that sympatric speciation can occur if intraspecific competition is strong enough to induce disruptive selection. However, the plausibility of the involved processes is under debate, and many questions on the conditions for speciation remain unresolved. For instance, is strong disruptive selection sufficient for speciation? Which roles do genetic architecture and initial composition of the population play? How strong must assortative mating be before a population can split in two? These are some of the issues we address here. We investigate a diploid multilocus model of a quantitative trait that is under frequency-dependent selection caused by a balance of intraspecific competition and frequency-independent stabilizing selection. This trait also acts as mating character for assortment. It has been established previously that speciation can occur only if competition is strong enough to induce disruptive selection. We find that speciation becomes more difficult for very strong competition, because then extremely strong assortment is required. Thus, speciation is most likely for intermediate strengths of competition, where it requires strong, but not extremely strong, assortment. For this range of parameters, however, it is not obvious how assortment can evolve from low to high levels, because with moderately strong assortment less genetic variation is maintained than under weak or strong assortment sometimes none at all. In addition to the strength of frequency-dependent competition and assortative mating, the roles of the number of loci, the distribution of allelic effects, the initial conditions, costs to being choosy, the strength of stabilizing selection, and the particular choice of the fitness function are explored. A multitude of possible evolutionary outcomes is observed, including loss of all genetic variation, splitting in two to five species, as well as very short and extremely long stable limit cycles. On the methodological side, we propose quantitative measures for deciding whether a given distribution reflects two (or more) reproductively isolated clusters. [source] Heat transfer by radiation and convection in fire testingFIRE AND MATERIALS, Issue 5 2004Ulf Wickström Abstract Fire safety engineers, especially those experts writing fire test standards, often have different understandings of the concepts of heat transfer from a fire to a surface by radiation and convection. The concepts are therefore often not very well defined, in e.g. ISO and CEN standards, leading in many cases to confusions, misunderstandings and considerable errors. This paper is an effort, in a very simple way, to make the issue a little clearer, particularly for use in international standardization work. ISO/TC92 and the International FORUM of Fire Research Directors are currently endorsing very important work on procedures to calibrate heat flux meters. The two entities, heat transfer by radiation and convection, may be treated independently. The presentation below is deliberately very short and basic avoiding many phenomena that are not immediately needed in most fire standardization work. Recommendations are reached on how to define and measure heat transfer in fire testing. Copyright © 2004 John Wiley & Sons, Ltd. [source] Infiltration of basinal fluids into high-grade basement, South Norway: sources and behaviour of waters and brinesGEOFLUIDS (ELECTRONIC), Issue 1 2003S. A. Gleeson Abstract Quartz veins hosted by the high-grade crystalline rocks of the Modum complex, Southern Norway, formed when basinal fluids from an overlying Palaeozoic foreland basin infiltrated the basement at temperatures of c. 220°C (higher in the southernmost part of the area). This infiltration resulted in the formation of veins containing both two-phase and halite-bearing aqueous fluid inclusions, sometimes with bitumen and hydrocarbon inclusions. Microthermometric results demonstrate a very wide range of salinities of aqueous fluids preserved in these veins, ranging from c. 0 to 40 wt% NaCl equivalent. The range in homogenization temperatures is also very large (99,322°C for the entire dataset) and shows little or no correlation with salinity. A combination of aqueous fluid microthermometry, halogen geochemistry and oxygen isotope studies suggest that fluids from a range of separate aquifers were responsible for the quartz growth, but all have chemistries comparable to sedimentary formation waters. The bulk of the quartz grew from relatively low ,18O fluids derived directly from the basin or equilibrated in the upper part of the basement (T < 200°C). Nevertheless, some fluids acquired higher salinities due to deep wall-rock hydration reactions leading to salt saturation at high temperatures (>300°C). The range in fluid inclusion homogenization temperatures and densities, combined with estimates of the ambient temperature of the basement rocks suggests that at different times veins acted as conduits for influx of both hotter and colder fluids, as well as experiencing fluctuations in fluid pressure. This is interpreted to reflect episodic flow linked to seismicity, with hotter dry basement rocks acting as a sink for cooler fluids from the overlying basin, while detailed flow paths reflected local effects of opening and closing of individual fractures as well as reaction with wall rocks. Thermal considerations suggest that the duration of some flow events was very short, possibly in the order of days. As a result of the complex pattern of fracturing and flow in the Modum basement, it was possible for shallow fluids to penetrate basement rocks at significantly higher temperatures, and this demonstrates the potential for hydrolytic weakening of continental crust by sedimentary fluids. [source] Viscoelastic,afterslip concurrence: a possible mechanism in the early post-seismic deformation of the Mw 7.6, 1999 Chi-Chi (Taiwan) earthquakeGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2004Shyh-Yang Sheu SUMMARY Observed coseismic data as well as 97 days of post-seismic GPS data for the Chi-Chi earthquake are used as constraints in the modelling of crustal evolution using the 3-D finite-element method. First, the coseismic GPS data are used to justify the use of the elastic earth model and the source rupture model. Subsequently, the most likely rheological model is determined by analysing several modelled time-dependent displacements for various viscosity structures. The range of viscosities of the lower crust in central Taiwan is determined in advance from laboratory measurements and the long-term strain rate. The estimated viscosity of 5.0 × 1017 Pa s seems to be very low and a relaxation time of 116 days seems very short, but the latter approximates the GPS measurement of 86 days. Since earlier studies have indicated that both the viscoelastic response model and the afterslip model may affect post-seismic deformation, we compare theoretical surface displacements for each of the two models that we evaluate. The results reveal that there is little doubt that while neither of these models alone is able to predict the GPS measurements well in a 97-day period, the combination of the two models improves the predictions considerably. We conclude that the afterslip mainly dominated Chi-Chi post-seismic deformation in the rupture area while the viscoelastic model did so elsewhere. [source] Screening for local and regional cancer recurrence in patients curatively treated for laryngeal cancer: Definition of a high-risk group and estimation of the lead timeHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 5 2007Savitri C. Ritoe MD Abstract Background. All patients treated for laryngeal cancer are offered the same follow-up schedule to detect asymptomatic locoregional recurrences. In this study, we evaluated the prognostic profile of patients for cancer recurrence and estimated the lead time. Methods. A cohort study was performed between 1990 and 1995. Cox proportional hazards model was used to analyze the prognostic factors. The effect of altering the follow-up for asymptomatic recurrence detection was determined after estimating the lead time. Results. The variables cT classification, smoking, and histologic grade proved to be prognostic factors. The risk of locoregional failure was 15% in the low-risk group versus 29% in the high-risk group. The estimated lead time was 2 to 4 weeks. Conclusion. Risk profiles for locoregional relapse were defined. Intensifying the follow-up schedule is not advisable because the lead time is very short. An excessively high number of routine visits would have to be performed to increase the detection rate for asymptomatic recurrences. © 2006 Wiley Periodicals, Inc. Head Neck, 2007 [source] What is the current evidence for antigen involvement in the development of chronic lymphocytic leukemia?HEMATOLOGICAL ONCOLOGY, Issue 1 2006Gerard Tobin Abstract For many years it has been evident that B-cell chronic lymphocytic leukemia (CLL) displays preferential usage of individual immunoglobulin (Ig) variable heavy chain (VH) genes. The VH1-69 gene was the first to be reported overrepresented in a large number of CLL patients, where the VH1-69+ CLL rearrangements showed characteristic molecular features, such as unmutated VH genes, usage of specific diversity/joining gene segments, and a longer than average complementarity determining region (CDR) 3 with certain common amino acid motifs. Also, biased usage of the VH3-07 and VH4-34 genes with specific rearrangement characteristics was reported in CLL. These findings led to the speculation that antigens could be involved during CLL development by triggering proliferation of B-cells with specific B-cell receptors (BCRs) leading to an increased risk of transforming events. Recently, we characterized a subset of CLL utilizing the VH3-21 gene that also displayed peculiar Ig features, e.g. very short and homologous CDR3s, predominant , expression and preferential V,2-14 gene usage. This VH3-21+ subgroup also had poor prognosis despite the fact that two-thirds of cases carried mutated VH genes. Moreover, we and others have thereafter described further CLL subsets with very similar heavy and light chain gene rearrangement features. These latter findings of subsets expressing restricted BCRs have emphasized the hypothesis that antigens could play a role during the pathogenesis of CLL. Interestingly, recombinant antibodies produced from these restricted subsets showed similar cytoplasmatic reactivity within each group, thus suggesting recognition of a limited number of autoantigens. Further characterization of antigens is now necessary in order to understand their nature and exact role in CLL development. Copyright © 2005 John Wiley & Sons, Ltd. [source] Tree-ring reconstructions of precipitation and streamflow for north-western TurkeyINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2008Ünal Akkemik Abstract We describe tree-ring reconstructions of spring (May-June) precipitation and spring-summer (May-August) streamflow for north-western Turkey, both beginning in AD 1650. These are among the first such reconstructions for the region, and the streamflow reconstruction is among the first of its kind for Turkey and the entire Middle East. The reconstructions, which both emphasize high-frequency variations, account for 34 and 53% of their respective instrumental variance. Comparison to precipitation and runoff data provides some means of verification for the instrumental streamflow record, which is very short (30 years). Drought and flood events in the reconstructions are compared to historical archives and other tree-ring reconstructions for Turkey. The results reveal common climatic extremes over much of the country. Many of these events have had profound impacts on the peoples of Turkey over the past several centuries. Copyright © 2007 Royal Meteorological Society [source] Comparison of performance of heat regenerators: Relation between heat transfer efficiency and pressure dropINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2001Françoise Duprat Abstract Heat regenerators transfer heat from one gas to another, with an intermediate storage in solids. The heat transfer surface for gas flow application should provide at the same time high surface area and low friction factor. Three geometries of heat transfer surface, monolith, stack of woven screens and bed of spheres, have been compared. Their performance was evaluated from the pressure drop of the heat regenerator working at a given heat transfer efficiency. The comparison was performed using numerical simulation and published measurements of heat transfer and flow friction characteristics. By adjusting the length and the period of the exchanger, it is possible to obtain the same heat transfer efficiency with the three geometries. Beds of spheres give very short and compact heat regenerators, working at high pressure drop. At the opposite, monoliths form long regenerators working at low pressure drop. Stacks of woven screens cover a wide range of performance: low porosity woven screens give high heat transfer efficiency and high pressure drop, while high porosity woven screens offer performance similar to that of the monoliths. Copyright © 2001 John Wiley & Sons, Ltd. [source] Improving the K6 short scale to predict serious emotional disturbance in adolescents in the USAINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue S1 2010Jennifer Greif Green Abstract Effective screening for emotional and behavioral disorders among youth requires brief screening scales with good validity to identify youth requiring further evaluation and to estimate prevalence of target disorders in populations of interest such as schools or neighborhoods. This paper examines the psychometric properties of a very short (six-item) screening scale, the K6, to assess serious emotional disturbance (SED) among youth. The K6, which is made up of symptoms of depression and anxiety, has been shown in previous research to be a strong predictor of serious mental illness (SMI) in adults, but no information is available on the ability of the scale to screen for SED among youth. The current report examines the K6 as a screen for SED in a national survey of US adolescents, the National Comorbidity Survey Replication Adolescent Supplement (NCS-A). The K6 is shown to provide fairly good prediction of SED [area under curve (AUC) = 0.74] that is somewhat higher for internalizing (AUC = 0.80) than behavior (AUC = 0.75) disorders. Based on this result, we augmented the K6 with questions about symptoms of behavior disorders. This improved prediction of SED (from AUC = 0.74 to AUC = 0.83) as well as of SED associated with pure behavior disorders (from AUC = 0.53 to AUC = 0.78). These results show that although the symptoms of depression and anxiety in the K6 are sufficient to detect SMI among adults, high rates of behavior disorders among adolescents require indicators of behavior disorders to be added to the K6 to screen adequately for adolescent SED. Copyright © 2010 John Wiley & Sons, Ltd. [source] Searching the global minimum of a peptide/bilayer potential energy surface by fast heating and cooling cycles of simulated annealingINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 13 2008C. A. Fuzo Abstract The total time reached by molecular dynamics simulation in the study of the interactions between hydrated bilayers and peptides is still very short. A scheme of fast heating and cooling cycles of simulated annealing (FHCCSA) is proposed to improve the efficiency of the search for the global minimum of the peptide/bilayer potential energy surface. In FHCCSA, the high temperatures facilitate the transitions between stable configurations; i.e., heating and cooling cycles make easier the escape of the system outside the local energy minimum. The FHCCSA efficiency is confirmed by comparing its results with conventional NpT simulations. The new scheme saves more than 90% of the total cpu time compared with ordinary NpT simulations. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Sperm ultrastructure of the hydrothermal vent octopod Vulcanoctopus hydrothermalisJOURNAL OF MORPHOLOGY, Issue 8 2010A. Roura Abstract Sperm ultrastructure of the deep-sea hydrothermal vent octopod Vulcanoctopus hydrothermalis has been carried out by transmission electron microscopy. Spermatozoa of this species have the shortest head observed so far in octopodids. The acrosome possesses a helix with six gyres. The rod-shaped nucleus is short and wide in relation with other octopodids. Noteworthy features along the nucleus are the regularly disposed dense bands of cytoplasm, which have not been observed before in octopodids. The nuclear fossa is very short and wavy. Mitochondrial sheath has 10 elongated mitochondria running parallel to the axoneme-coarse fibers complex. Sperm morphology of V. hydrothermalis resembles that of Enteroctopus dofleini, suggesting a close phylogenetic relationship. J. Morphol. 271:932,936, 2010. © 2010 Wiley-Liss, Inc. [source] Structural, spectroscopic, and theoretical studies of a very short OHO hydrogen bond in bis(4-(N -methylpiperidinium)-butyrate) hydrobromideJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 5 2009bieta Bartoszak-Adamska Abstract The molecular structure of bis(4-(N -methylpiperidinium)-butyrate) hydrobromide, (MPBu)2HBr, has been characterized by single crystal X-ray diffraction, infrared and NMR spectroscopies, and by DFT calculations. The crystals of the title compound at 140,K are monoclinic, space group C2/c, with a,=,11.7118(4), b,=,7.8737(2), c,=,23.9240(8),Å3,, ,,=,90.431(3)°, V,=,2206.1(1),Å3, and Z,=,4. Two 4-(N -methylpiperidinium)-butyrate moieties are joined by a very short and centrosymmetric O.H.O hydrogen bond of 2.436(2),Å3,. The piperidine ring adopts a chair conformation with the methyl group in the equatorial and the bulky (CH2)3COO substituent in the axial position. The broad absorption band below 1500,cm,1 in the FTIR spectrum confirms the existence of a very short O,H,O hydrogen bond. The 1H and 13C NMR spectra are interpreted on the basis of 2D experiments and the calculated GIAO/B3LYP/6-31G(d,p) magnetic isotropic shielding tensors. In the optimized structure of the complex, a 4-(N -methylpiperidinium)-butyrate zwitterion interacts with a 4-(N -methylpiperidinium)-butyric acid cation forming an O,. HO hydrogen bond of 2.580,Å3,. Copyright © 2008 John Wiley & Sons, Ltd. [source] Dentists' preferences of anterior tooth proportion,a Web-based studyJOURNAL OF PROSTHODONTICS, Issue 3 2000Stephen F. Rosenstiel BDS Purpose This study aimed to determine dentists' esthetic preferences of the maxillary anterior teeth as influenced by different proportions. The goal was to link choices to demographic data as to the experience, gender, and training of the dentist. Materials and Methods Computer-manipulated images of the 6 maxillary anterior teeth were generated from a single image and assigned to 5 tooth-height groups (very short, short, normal height, tall, and very tall). For each group, 4 images were generated by manipulating the relative proportion of the central incisors, lateral incisors, and canines according to the proportions 62% (or "golden proportion"), 70%, 80%, and "normal" or not further altered. The images were randomly ordered on a web page that contained a form asking for demographic data and fields asking for a ranking of the images. Dentists were asked via e-mail to visit the web page and complete the survey. The responses were tabulated and analyzed with repeated measures logistic regression with the alpha at 0.05. A subset of North American respondents was chosen for further analysis. Results A total of 549 valid responses were received and analyzed from dentists in 38 countries. There were statistically significant differences in all groups for the variables of proportion, group (tooth height), and their interaction. The 80% proportion was judged best for the Very Short and Short groups. Three of the choices were almost equally picked for the Normal Height and Tall groups, and the golden proportion was judged best for the Very Tall group. The variables of year of graduation, gender, professional activity, generalist or specialist, or number of patients were not significantly correlated with the choices for the North American respondents. Conclusions Dentists preferred the 80 percent proportion when viewing short or very short teeth and the golden proportion when viewing very tall teeth. Golden proportion was worst for normal height or shorter teeth and the 80% proportion for tall or very tall teeth. They picked no clear-cut best for normal height or tall teeth, and their choices could not be predicted based on gender, specialist training, experience, or patient load. [source] Systematic review: the effects of carbonated beverages on gastro-oesophageal reflux diseaseALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2010T. JOHNSON Aliment Pharmacol Ther,31, 607,614 Summary Background, Carbonated beverages have unique properties that may potentially exacerbate gastro-oesophageal reflux disease (GERD), such as high acidity and carbonation. Cessation of carbonated beverage consumption is commonly recommended as part of lifestyle modifications for patients with GERD. Aims, To evaluate the relationship of carbonated beverages with oesophageal pH, oesophageal motility, oesophageal damage, GERD symptoms and GERD complications. Methods, A systematic review. Results, Carbonated beverage consumption results in a very short decline in intra-oesophageal pH. In addition, carbonated beverages may lead to a transient reduction in lower oesophageal sphincter basal pressure. There is no evidence that carbonated beverages directly cause oesophageal damage. Carbonated beverages have not been consistently shown to cause GERD-related symptoms. Furthermore, there is no evidence that these popular drinks lead to GERD complications or oesophageal cancer. Conclusions, Based on the currently available literature, it appears that there is no direct evidence that carbonated beverages promote or exacerbate GERD. [source] Quality of life in functional dyspepsia: responsiveness of the Nepean Dyspepsia Index and development of a new 10-item short formALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 2 2001N. J. Talley Background: The Nepean Dyspepsia Index is a reliable and valid measure of quality of life in functional dyspepsia, but responsiveness has been little studied. The Nepean Dyspepsia Index originally contained 42 items designed to measure impairment of a subject's ability to engage in relevant aspects of their life because of dyspepsia, and their enjoyment of these aspects; in addition, the individual importance of areas was assessed. It was subsequently shortened to 25 items, yielding five sub-scales. Aim: To test the Nepean Dyspepsia Index's responsiveness and develop a responsive, very short form. Methods: A randomized, double-blind controlled trial was performed in 589 patients with documented functional dyspepsia. Symptoms and quality of life were measured at baseline, 2 and 4 weeks. Responsiveness of the Nepean Dyspepsia Index quality-of-life section was evaluated by correlation with symptom scores and calculation of standardized changes in scores. Two items from each sub-scale which best represented the area of life (by factor loadings) were selected to create the 10-item short form (SF; short form-Nepean Dyspepsia Index). Internal consistency was assessed by Cronbach's alpha and responsiveness was assessed as above. Results: The Nepean Dyspepsia Index quality-of-life scales demonstrated excellent responsiveness to change in both the active and placebo arms (standardized response means all > 1.0). The Nepean Dyspepsia Index accounted for only 8% of the variance in percentage change in symptoms (by visual analogue scales), indicating that it was evaluating areas of life not covered by symptoms. The 10-item short form had adequate internal consistency (all scales , 0.70) and all strongly (and significantly) correlated with the long form sub-scales; it was also highly responsive. Conclusion: The Nepean Dyspepsia Index is a responsive disease-specific quality-of-life measure; the 10-item short form can be applied in clinical trials of functional dyspepsia. [source] Shock-melted material in the Krymka LL3.1 chondrite: Behavior of the opaque mineralsMETEORITICS & PLANETARY SCIENCE, Issue 2 2005Vira P. Semenenko The shock pressure, nominally in the range of 75,90 GPa, could only have been 30,35 GPa in a porous material like fine-grained matrix. The melted regions have an igneous texture and their silicates are zoned and unequilibrated. Large metal-troilite intergrowths formed in these regions. The metal has a nickel content corresponding to martensite and the troilite contains up to 4.2 wt% nickel. Melting must have been very short and cooling very fast (>100 °C/h at high temperature). The metal contains up to 0.7 wt% phosphorus. Abundant chromite crystals and sodium-iron phosphate glass globules are found in troilite. The differences in composition between the opaque phases found in the melted regions and those generally observed in unmetamorphosed chondrules are assigned to melting under closed system conditions. Surprisingly high Co concentrations (up to 13 wt%) were found in some metal grains in or at the periphery of melted regions. They likely resulted from sulfurization of metal by sulfur vapor produced during the shock. After solidification, at least one other shock led to mechanical effects in the melted regions. [source] The performance of QoS-aware IP multicast routing protocols,NETWORKS: AN INTERNATIONAL JOURNAL, Issue 2 2003Chih-Jen Tseng Abstract Research in the area of QoS-aware dynamic multicast routing protocols has been very active in recent years. Protocols based on dynamic Steiner tree strategies, such as YAM and QoSMIC, have been consistently shown to outperform those based on shortest path heuristics, such as PIM and DVMRP. However, these protocols all suffer from the problem of poor scalability for one or more of the following reasons: high control overhead, insufficient robustness with the adoption of a centralized group manager, and excessively long join latency. In addition, these protocols perform well only when group members are either densely populated or sparsely populated, but, unfortunately, not both. In this paper, we propose a protocol, named DSDMR, which can adapt its strategy based on sensed group member densities. Underlying DSDMR is an adaptive two-direction join mechanism that tries to find good attaching points for new group members either from the source or from the new joining member depending on member densities. We evaluate our scheme using extensive simulations and found that DSDMR can build multicast trees with costs close to the best greedy strategy, very low control overhead, and very short join latency across a wide member density spectrum. Furthermore, its success ratio is only slightly lower than is the best greedy strategy in finding feasible routes subject to both bandwidth and end-to-end delay constraints. © 2003 Wiley Periodicals, Inc. [source] Mixed singlet-triplet superconducting state in doped antiferromagnetsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2006A. Maci¸ag Abstract We analyze symmetry mixing in the superconducting (SC) order parameter of planar cuprates. The behavior of thermal conductivity observed in some systems doped with magnetic impurities or in some systems exposed to external magnetic field seems to indicate that such symmetry mixing takes place. We discuss this phenomenon in the framework of the spin polaron model (SPM). We assume that antiferromagnetic (AF) correlations, which are at least of short range, tend to confine motion of holes which have been created in the AF spin background. The nature of the propagation of quasiparticles which are hole-like and the nature of the interaction between quasiparticles is determined by a tendency to restore the local AF order. It is known that two holes in the t ,J model (tJ M) form bound states with dx 2,y2 or p-wave symmetry. The d-wave bound state has lower energy and is the ground state. The mixing of d-wave symmetry with p-wave symmetry takes place in the SC order parameter at some range of finite values of the doping parameter. That range lies at the applicability verge of the SPM, where AF correlation are already very short. On the other hand, these correlations may be strengthened by above mentioned external factors, which seems to explain why symmetry mixing is observed in this case. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis and molecular structure of Cr(salen)(,-N)RhCl(COD): the first example of a heterobimetallic nitride-bridged complex containing chromiumACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2010Johan Vibenholt Five-coordinate Cr(N)(salen) {salen is 2,2,-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolate} reacts with [RhCl(COD)]2 (COD is 1,5-cyclooctadiene) to yield the heterobimetallic nitride-bridged title compound, namely chlorido-2,Cl -[2(,4)-1,5-cyclooctadiene]{2,2,-[ethane-1,2-diylbis(nitrilomethylidyne)]diphenolato-1,4O,N,N,,O,}-,-nitrido-1:2,2N:N -chromium(V)rhodium(I), [CrRh(C16H14N2O2)ClN(C8H12)]. The Cr,N bond of 1.5936,(14),Å is elongated by only 0.035,Å compared to the terminal Cr,N bond in the precursor. The nitride bridge is close to being linear [173.03,(9)°] and the Rh,N bond of 1.9594,(14),Å is very short for a monodentate nitrogen-donor ligand, indicating significant ,-acceptor character of the Cr[triple-bond]N group. [source] Apparent shortening of the Csp3,Csp3 bond analysed via a variable-temperature X-ray diffraction study in racemic 1,1,-binaphthalene-2,2,-diyl diethyl bis(carbonate)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 5 2009Susanta K. Nayak Crystal structure determination at room temperature [292,(2),K] of racemic 1,1,-binaphthalene-2,2,-diyl diethyl bis(carbonate), C26H22O6, showed that one of the terminal carbon,carbon bond lengths is very short [Csp3,Csp3 = 1.327,(6),Å]. The reason for such a short bond length has been analysed by collecting data sets on the same crystal at 393, 150 and 90,K. The values of the corrected bond lengths clearly suggest that the shortening is mainly due to positional disorder at two sites, with minor perturbations arising as a result of thermal vibrations. The positional disorder has been resolved in the analysis of the 90,K data following the changes in the unit-cell parameters for the data sets at 150 and 90,K, which appear to be an artifact of a near centre of symmetry relationship between the two independent molecules in the space group P at these temperatures. Indeed, the unit cell at low temperature (150 and 90,K) is a supercell of the room-temperature unit cell. [source] Sperm motility and seminal plasma characteristics in Barbus sharpeyi (Günther, 1874)AQUACULTURE RESEARCH, Issue 10 2010Sayyed Mohammad Hadi Alavi Abstract Spermatozoa concentration, ionic composition, osmolality, glucose and total protein contents of seminal plasma and sperm motility were determined in Barbus sharpeyi (Cyprinidae, Teleosotei). Spermatozoa concentration ranged from 9.77 to 20.20 × 109 spermatozoa mL,1. Osmolality (mOsmol kg,1) and ionic contents (mM L,1) of the seminal plasma were 274.5±9.0, 70.0±3.4 Na+, 28.8±0.9 K+, 101.7±3.1 Cl,, 0.9±0.1 Mg2+ and 2.1±0.1 Ca2+ respectively. Total protein and glucose were 5.3±0.2 g L,1 and 76.7±4.3 mM L,1 respectively. Sperm motility was initiated in a hypo-osmotic condition, composed of either an ionic (KCl or NaCl) or a non-ionic (sucrose) activation medium. Duration of sperm motility was very short: <2 min after activation in distilled water. Percentage of motile spermatozoa was significantly higher in an activation medium containing NaCl compared with that of distilled water. An activating medium containing NaCl or KCl higher than 150 mM or sucrose higher than 275 mM totally inhibited the activation of sperm motility. Immediately after sperm activation, wave(s) propagated along the flagellum, but waves were restricted to the proximal part of the flagellum (close to the head) at 1 min post activation. Studied characteristics in the present study were compared with those of other cyprinids for understanding inter-species differences. [source] Tumor necrosis factor antagonist therapy and lymphoma development: Twenty-six cases reported to the Food and Drug Administration,ARTHRITIS & RHEUMATISM, Issue 12 2002S. Lori Brown PhD Objective Etanercept and infliximab are tumor necrosis factor (TNF) antagonists that have been recently approved for the treatment of rheumatoid arthritis (RA) and Crohn's disease (CD). This study was undertaken to investigate the occurrence of lymphoproliferative disorders in patients treated with these agents. Methods Relevant data in the MedWatch postmarket adverse event surveillance system run by the US Food and Drug Administration were reviewed. Results We identified 26 cases of lymphoproliferative disorders following treatment with etanercept (18 cases) or infliximab (8 cases). The majority of cases (81%) were non-Hodgkin's lymphomas. The interval between initiation of therapy with etanercept or infliximab and the development of lymphoma was very short (median 8 weeks). In 2 instances (1 infliximab, 1 etanercept), lymphoma regression was observed following discontinuation of anti-TNF treatment, in the absence of specific cytotoxic therapy directed toward the lymphoma. Conclusion Although data from a case series such as this cannot establish a clear causal relationship between exposure to these medications and the risk of lymphoproliferative disease, the known predisposition of patients with RA and CD to lymphoma, the known excess of lymphoma in other immunosuppressed populations, and the known immunosuppressive effects of the anti-TNF drugs provide a biologic basis for concern and justification for the initiation of additional epidemiologic studies to formally evaluate this possible association. [source] Assembling the stratigraphic record: depositional patterns and time-scales in an experimental alluvial basinBASIN RESEARCH, Issue 3 2002B. A. Sheets ABSTRACT Our understanding of sedimentation in alluvial basins is best for very short and very long time-scales (those of bedforms to bars and basinwide deposition, respectively). Between these end members, the intermediate time-scales of stratigraphic assembly are especially hard to constrain with field data. We address these ,mesoscale' fluvial dynamics with data from an experimental alluvial system in a basin with a subsiding floor. Observations of experimental deposition over a range of time-scales illustrate two important properties of alluvial systems. First, ephemeral flows are disproportionately important in basin filling. Lack of correlation between flow occupation and sedimentation indicates that channelized flows serve mainly as conduits for sediment, while most deposition occurs via short-lived unchannelized flow events. Second, there is a characteristic time required for individual depositional events to average to basin-scale stratal patterns. This time can be scaled in terms of the time required for a single channel-depth of aggradation, and in this form is constant through a four-fold variation of experimental subsidence rate. [source] | |||||||||||||||||||||||||