bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Elastic Modulus of β‐HMX Crystals Determined by Nanoindentation
Authors: Li Ming , Tan Wu‐Jun , Kang Bin , Xu Rui‐Juan , Tang Wei 
Published: January 2010

AbstractThis paper presents an investigation on the anisotropic modulus of energetic crystals of β‐HMX by using a Hysitron Triboindenter fitted with a Berkovich tip. High quality single crystals of β‐HMX, whose densities were determined by high precision density gradient tube (DGT), were used in order to extract the moduli of two orthogonal crystal faces: (010), the maximum growth habit face (termed face 1), and the face which is perpendicular to it (termed face 2). Contrary to common expectation, the moduli of face 1 and face 2 were found to be 23.4 and 26.1 GPa, respectively, indicating a negligible crystal anisotropy of the system. Nanoindentation measurement gave even narrower difference, with hardness values of 1.1 GPa for face 1 and 0.95 GPa for face 2, thus further supporting the above conclusion. The result obtained from nanoindentation contradicts with those from the impulse stimulated light scattering (ISLS) and the Brillouin scattering, but was close to the result predicted by molecular dynamics (MDs) simulation. It is also suggested that the modulus value of 31 GPa obtained from previous micro‐indentation measurement may be overestimated.
Coupling a mass‐conserving semi‐Lagrangian scheme (SLICE) to a semi‐implicit discretization of the shallow‐water equations: Minimizing the dependence on a reference atmosphere
Authors: Thuburn J. , Zerroukat M. , Wood N. , Staniforth A. 
Published: January 2010

AbstractIn a recent paper, a conservative semi‐Lagrangian mass transport scheme SLICE has been coupled to a semi‐implicit semi‐Lagrangian scheme for the shallow‐water equations. The algorithm involves the solution at each timestep of a nonlinear Helmholtz problem, which is achieved by iterative solution of a linear ‘inner’ Helmholtz problem; this framework, as well as the linear Helmholtz operator itself, are the same as would be used with a non‐conservative interpolating semi‐Lagrangian scheme for mass transport. However, in order to do this, a reference value of geopotential was introduced into the discretization. It is shown here that this results in a weak dependence of the results on that reference value. An alternative coupling is therefore proposed that preserves the same solution framework and linear Helmholtz operator but, at convergence of the nonlinear solver, has no dependence on the reference value. However, in order to maintain accuracy at large timesteps, this approach requires a modification to how SLICE performs its remapping. An advantage of removing the dependence on the reference value is that the scheme then gives consistent tracer transport. Copyright © 2010 Royal Meteorological Society and Crown Copyright. Published by John Wiley & Sons, Ltd.
A radius –depth model for midlatitude cyclones in reanalysis data and simulations
Authors: Schneidereit Andrea , Blender Richard , Fraedrich Klaus 
Published: January 2010

AbstractGeometric properties of winter (DJF) and summer (JJA) midlatitude cyclones are analysed in reanalysis data, present‐day and global warming simulations. Cyclone centres are identified by the minima of the 1000 hPa geopotential height. Fitting an azimuthally symmetric Gaussian function to the surrounding height field provides cyclone depth (difference between the cyclone centre and the synoptic environment), radius (standard deviation), geostrophic wind and vorticity. Analysing ERA‐40 reanalysis data of different resolutions and Intergovernmental Panel on Climate Change (IPCC) scenario simulations by the coupled atmosphere–ocean general circulation model ECHAM5/MPI‐OM yields mean radii of 300–500 km in winter and 300–400 km in summer. Depth maxima occur in the storm tracks (determined by the bandpass‐filtered variance of the geopotential height), and the smallest radii characterize oceanic cyclogenesis regions. The geostrophic vorticity, derived from the fitted Gaussian model, agrees reasonably well with the observed relative vorticity. Future warmer climate scenarios exhibit smaller radii and weaker depths during winter and summer. An intense growth of the depth is found during the 2 –10 day cyclone life cycles, while the radii reveal negligible growth. Compositing depths with respect to normalized total lifetime leads to rescaled depth life cycles, which collapse to a simple universal function, ã(1 − ã), for relative cyclone age ã. Copyright © 2010 Royal Meteorological Society
Generalizing ‘z‐less’ mixing length for stable boundary layers
Authors: Grisogono B. 
Published: January 2010

AbstractCurrent research shows, recent and former research suggests, that the nature and evolution of the stable atmospheric boundary layer(s) (SABL) is still understood and modelled inadequately. The ‘classical’ SABL, almost always stratified weakly (i.e. gradient Richardson number Ri ≪ ∞, typically 0 < Ri ≤ 1), has been modelled reasonably well during the last few decades or so, but the very stable case, i.e. the VSABL (Ri ≫ 1), is generally not well understood. Excessively diffusive and much too deep VSABL flows, as often appearing in numerical models, were recently addressed; the over‐diffusion was alleviated by improving the local turbulent mixing length. This demands an explicit inclusion of the vertical shear of horizontal wind, S, in the mixing length, besides the previously known role of buoyancy frequency, N. A generalization of this recent work is given here by a simplified turbulent kinetic energy (TKE) equation and a set of subsequent parametrizations for the eddy diffusivity and conductivity, i.e. K‐parametrizations, in terms of a generalized ‘z‐less’ mixing length, Λ. The aim is to produce a parametrization that is uniformly valid for all Ri ≥ 0. It is shown that Λ ∼ (TKE)1/2/ | S | ·f(Ri, Pr), uniformly valid for 0 ≤ Ri, regardless of the other parametrization details (the details appear as corrections); Pr is the turbulent Prandtl number and f(Ri, Pr) is a simple set of derived functions depending on the parametrization properties.A couple of important shortcomings of the current turbulence parametrizations for the SABL, as modelled in numerical weather prediction, air‐chemistry and climate models, will be remedied by using this new generalized ‘z‐less’ mixing length. This approach also recommends that it should be better if various mixing length scales were derived from simplified main principles, instead of only being guessed from plausible reasoning or dimensional analysis. In particular, it has often been assumed that K and Λ profiles could be chosen for modelling purposes more or less independently from each other. It is shown, based on a simple renormalization for Λ, that this is not the case if one wishes to use a more consistent parametrization scheme. Copyright © 2010 Royal Meteorological Society
Convergence properties of the primal and dual forms of variational data assimilation
Authors: Akkraoui Amal El , Gauthier Pierre 
Published: January 2010

AbstractThe variational data assimilation problem can be solved in either its primal (3D/4D‐Var) or dual (3D/4D‐PSAS) form. The methods are equivalent at convergence but the dual method exhibits a spurious behaviour at the beginning of the minimization which leads to less probable states than the background state. This is a serious concern when using the dual method in operational implementations when only a finite number of iterations can be afforded. Two classes of minimization algorithms are examined in this article: the conjugate gradient (CG) and the minimum residual (MINRES) methods. While the CG algorithms ensure a monotonic reduction of the cost function, those based on the MINRES enforce instead a monotonic decrease of the norm of the gradient. In this article, it is shown that when applied to the minimization of the dual problem, the MINRES algorithms also lead to iterates for which their ‘image’ in physical space leads to a monotonic decrease of the primal cost function. A relationship is established showing that the primal objective function is related to the value of the dual cost function and the norm of its gradient. This holds for the incremental forms of both the three‐ and four‐dimensional cases. A new convergence criterion is introduced based on the error norm in model space to make sure that, for the dual problem, the same accuracy is obtained in the analysis when only a finite number of iterations is completed. Copyright © 2010 Royal Meteorological Society
The influence of rotational frontogenesis and its associated shearwise vertical motions on the development of an upper‐level front
Authors: Lang Andrea A. , Martin Jonathan E. 
Published: January 2010

AbstractThe total quasi‐geostrophic (QG) vertical motion is partitioned into transverse and shearwise couplets oriented parallel to, and along, the geostrophic vertical shear, respectively, in order to examine the role of rotational frontogenesis, and its associated shearwise circulation, in the life cycle of an upper‐front/jet system in northwesterly flow. In particular the analysis emphasizes two aspects of that role: (1) the influence of shearwise ω on scalar frontogenesis, and (2) the effect of rotational frontogenesis, and its associated vertical circulation, on the initiation of along‐flow cold air advection during upper frontogenesis.The case‐study analysis reveals that shearwise subsidence persistently and significantly contributes to scalar frontogenesis throughout the life cycle. The transverse subsidence contribution to scalar frontogenesis is initially weak but grows more substantial after the establishment of along‐flow cold air advection near the base of the thermal trough.Prior work has argued that the development of along‐flow cold air advection arises from a cyclonic rotation of ∇θ promoted either by contributions from tilting or horizontal kinematics. From the QG perspective adopted in the present study, the tilting and kinematic rotations are seen as interconnected aspects of a single, underlying dynamical process: rotational frontogenesis, in which the rotation of ∇θ produced by vertical vorticity is accompanied by a discrete vertical circulation (the shearwise circulation) that provides the subsidence upshear of the vorticity maximum required to initiate along‐flow cold air advection. It is further suggested that the characteristic distribution of the kinematic and tilting contributions to rotation of ∇θ in the vicinity of an upper‐tropospheric vorticity maximum underlies the observed preference for the development of upper‐level fronts in northwesterly flow. Copyright © 2010 Royal Meteorological Society
Intraseasonal variability of the ocean — atmosphere coupling in the Gulf of Guinea during boreal spring and summer
Authors: Coëtlogon Gaëlle de , Janicot Serge , Lazar Alban 
Published: January 2010

AbstractStatistical analyses of the satellite TMI sea‐surface temperature (SST) and QuikSCAT surface winds in boreal spring and summer are performed to investigate the intraseasonal variability of air–sea interactions in the Gulf of Guinea. There, empirical orthogonal function decomposition shows the existence of peaks around 15 days, and their lagged cross‐correlation the signature of an expected 5‐day lag wind forcing and 3‐day lag strong negative SST feedback. Lagged linear regressions are performed onto a reference SST index of the cold tongue northern front in the Gulf of Guinea. A cold SST anomaly covering the equatorial and coastal upwelling is forced after about one week by stronger‐than‐usual south‐easterlies linked to the St Helena anticyclone, suggesting that intraseasonal variability in the Gulf of Guinea is connected to large‐scale fluctuations in the South Atlantic. Within about 5°S and 5°N, two retroactions between SST and surface wind appear to dominate near‐surface atmosphere conditions. When the wind leads the SST, stronger monsoonal winds north of 2°N are partly sustained by the developing SST anomaly and bring more humidity and rainfall toward the continent. When the SST leads the wind, a reversal of anomalous winds is observed mainly south of 2°N, closing a negative feedback loop with a biweekly periodicity. Eventually, further investigation with an ocean model emphasizes the contribution of the horizontal advection in shaping these intraseasonal SST signals. The contribution of vertical processes may also be important but was more difficult to estimate. Copyright © 2010 Royal Meteorological Society
A composite look at short‐time‐scale sea‐surface temperature changes in the western North Pacific based on ships and buoys
Authors: Danielson Richard E. , Gyakum John R. 
Published: January 2010

AbstractA simple method of interpolating sea‐surface temperature (SST) and its measurement method is applied to western North Pacific ship and buoy observations taken between 1970 and 2000. Comparisons are made between the resulting quasi‐daily in situ analyses and more inclusive analyses based mainly on satellite infrared observations. In terms of analysis differences, spatial correlation, and temporal spectra, the in situ analyses are found to be of moderate quality and are taken to be appropriate for composite diagnoses. This use is illustrated in a novel comparison of short‐time‐scale SST changes observed during the passage of two groups of midlatitude cold‐season cyclones.Transient cooling is found to be preferentially associated with the stronger of the two cyclone groups. The significance of this cooling is quantified and the possibility of oceanic mixed‐layer cooling and heat loss from bucket observations is explored. Although the bias in bucket observations is confirmed using composites constructed without such observations, the signature of transient cooling is still apparent. (Independent bucket observations also permit composite analysis errors to be estimated.) Engine intake observations are then identified as a primary source of both SST information in general and of the transient cooling signal in particular. A related bias in this type of observation is proposed. Greater sophistication in the analysis of in situ observations is also briefly discussed. Copyright © 2010 Royal Meteorological Society
Dose‐response analyses using restricted cubic spline functions in public health research
Authors: Desquilbet Loic , Mariotti François 
Published: January 2010

AbstractTaking into account a continuous exposure in regression models by using categorization, when non‐linear dose‐response associations are expected, have been widely criticized. As one alternative, restricted cubic spline (RCS) functions are powerful tools (i) to characterize a dose‐response association between a continuous exposure and an outcome, (ii) to visually and/or statistically check the assumption of linearity of the association, and (iii) to minimize residual confounding when adjusting for a continuous exposure. Because their implementation with SAS® software is limited, we developed and present here an SAS macro that (i) creates an RCS function of continuous exposures, (ii) displays graphs showing the dose‐response association with 95 per cent confidence interval between one main continuous exposure and an outcome when performing linear, logistic, or Cox models, as well as linear and logistic‐generalized estimating equations, and (iii) provides statistical tests for overall and non‐linear associations. We illustrate the SAS macro using the third National Health and Nutrition Examination Survey data to investigate adjusted dose‐response associations (with different models) between calcium intake and bone mineral density (linear regression), folate intake and hyperhomocysteinemia (logistic regression), and serum high‐density lipoprotein cholesterol and cardiovascular mortality (Cox model). Copyright © 2010 John Wiley & Sons, Ltd.
A U‐statistics‐based approach for modeling Cronbach coefficient alpha within a longitudinal data setting
Authors: Yan Ma , Alejandro Gonzalez Della Valle , Hui Zhang , Tu X. M. 
Published: January 2010

AbstractCronbach coefficient alpha (CCA) is a classic measure of item internal consistency of an instrument and is used in a wide range of behavioral, biomedical, psychosocial, and health‐care‐related research. Methods are available for making inference about one CCA or multiple CCAs from correlated outcomes. However, none of the existing approaches effectively address missing data. As longitudinal study designs become increasingly popular and complex in modern‐day clinical studies, missing data have become a serious issue, and the lack of methods to systematically address this problem has hampered the progress of research in the aforementioned fields. In this paper, we develop a novel approach to tackle the complexities involved in addressing missing data (at the instrument level due to subject dropout) within a longitudinal data setting. The approach is illustrated with both clinical and simulated data. Copyright © 2010 John Wiley & Sons, Ltd.
The dialectical systems theory's capacity for multi‐criteria decision‐making
Authors: Čančer Vesna , Mulej Matjaž 
Published: January 2010

AbstractThe article introduces the Quantified Dialectical Systems Theory (DST), which is one of the cases of new systems theories. It arises from the need for the appropriate knowledge about the basics of both systems theory and the applied computer supported qualitative and quantitative methods that can help individuals or groups in researching important complex decision‐making problems; among them we emphasize the multi‐criteria decision‐making (MCDM) ones. Moreover, the article presents the framework procedure for MCDM, based on assigning weights, which we developed by following the original procedures of several MCDM methods, adapted mainly by the conclusions of experts in practice regarding the suitability of different multi‐criteria methods, and own experience. We demonstrate how the DST's guidelines defining the subjective starting points can be followed when approaching MCDM problems step‐by‐step, as well as the DST's guidelines concerning implementation of starting points. In the efforts to support creating and decision‐making it helps a lot, if the application of theory can take place in an informal style. This article introduces ways of incorporation of informal systemic thinking and the DST's guidelines in the framework procedure for MCDM when solving several real‐life complex problems, presented by example cases. Copyright © 2010 John Wiley & Sons, Ltd.
Intrabiliary Rupture of Hepatic Echinococcosis, a Risk Factor for Developing Postoperative Morbidity: A Cohort Study
Authors: Manterola Carlos , Vial Manuel , Sanhueza Antonio , Contreras Juan 
Published: January 2010

AbstractBackgroundThe aim of this study was to determine if intrabiliary rupture (IBR), an evolutive complication of hepatic echinococcosis (HE), is a risk factor for developing postoperative morbidity (POM).MethodsThis was a concurrent cohort study that included patients operated on for HE between 1996 and 2006 and who had clinical check‐ups at 1, 6, 12, 24, 36, 48, and 60 months postoperatively. Principal outcome variable was “development POM,” considered dichotomously. The exposure variable was the presence of IBR, analyzed dichotomously (present or absent) and according to the number of IBR (without, with one, and with two or more). The sample size was considered on the basis of a 95% confidence interval (95% CI), a power of 80%, a 1:2 ratio of patients without and with IBR, and a 10% proportion of POM in patients without IBR and 26% in patients with IBR. Descriptive statistics and bivariate and multivariate analyses were used. Relative risks (RR) and 95% CI were calculated.ResultsThe cohorts (median age of 42 years, 56.4% female, a median cyst diameter of 15 cm, and a follow‐up of 118 months) were composed of 96 patients without IBR (38.1%) and 156 patients with IBR (61.9%). A morbidity rate of 17.1% was verified (9.4% in the group without IBR and 21.8% in the group with IBR [p = 0.011]). An adjusted RR of 3.4 (95% CI = 2.64, 4.18) was verified for the comparison of subgroups without IBR vs. with two or more IBR (p < 0.001).ConclusionThe presence of two or more IBR constitutes a risk factor for developing POM in patients with HE.
Advancing a Community Psychology of Men
Authors: Watts Roderick J. 
Published: January 2010

AbstractThis commentary reviews and integrates several themes described in this special issue on men. Social forces of the past and present such as colonialism and hegemonic masculinity are noted as a continuing influence on men's social roles, as are the social‐justice movements that contribute to the liberation of women and sexual minorities. The early sections of the commentary examine the studies in the context of these forces and movements, emphasizing how men both resist and accept traditional masculinities. In the latter sections the commentary turns to the research process –first with a discussion of the structural and constructionist themes in the studies, followed by the issue of how men are classified (implicitly or otherwise) as either agents or targets of oppression. The implications of these for community psychology research with men are considered, along with the idea that research is a social “performance” in which a researcher's concern about her or his audience influence the research process. The conclusion summarizes the challenges of conducting research with men while making the case that community psychology offers some distinct advantages in managing them. Of particular value is the field's emphasis on diversity, social justice, and social ecology.
No relationship between the ins del polymorphism of the serotonin transporter promoter and pain perception in fibromyalgia patients and healthy controls
Authors: Potvin Stéphane , Larouche Annie , Normand Edith , de Souza Juliana Barcellos , Gaumond Isabelle , Marchand Serge , Grignon Sylvain 
Published: January 2010

AbstractBackground:In animals, decades of research have shown that serotonin (5‐HT) is involved in endogenous pain inhibition systems, which are deficient in chronic pain disorders such as fibromyalgia (FM). In humans, there is preliminary evidence showing that 5‐HT is involved in the FM pathophysiology. In the current endophenotyping study, we sought to investigate, for the first time in humans, the relationships between the serotonin transporter promoter region (5‐HTTLPR) polymorphism and experimentally‐induced pain perception/inhibition in healthy controls (HC) and FM patients.Methods:Participants were 58 FM patients and 60 HC, who did not differ in age, sex or menstrual cycle. Thermal stimuli were used to measure pain thresholds. Pain inhibition was elicited using a tonic thermal test (Peltier thermode) administered before and after activation of the diffuse noxious inhibitory controls (DNIC) by means of a cold‐pressor test (CPT).Results:Thermal pain thresholds were higher in HC compared to FM patients. Pain ratings during the CPT were lower in HC, relative to FM patients. Also, DNIC efficacy was stronger in HC compared to FM patients. However, there was no relationship between 5‐HTTLPR and experimentally‐induced pain perception/inhibition.Discussion:Our results further confirm that FM is associated with thermal hyperalgesia and deficient DNIC. However, we found no evidence showing that the 5‐HTTLPR polymorphism influences pain perception and DNIC. Potential reasons for this negative result will be discussed. Further endophenotyping studies of 5‐HT‐related gene polymorphisms are required to ascertain the potential relationships between 5‐HT and human pain perception/inhibition.