bluuebunny/crossref_metadata_2025_split huggingface dataset:
Formation of Jets by Baroclinic Turbulence
Authors: Farrell Brian F. , Ioannou Petros J. 
Published: May 2008

Abstract
Turbulent fluids are frequently observed to spontaneously self-organize into large spatial-scale jets; geophysical examples of this phenomenon include the Jovian banded winds and the earth’s polar-front jet. These relatively steady large-scale jets arise from and are maintained by the smaller spatial- and temporal-scale turbulence with which they coexist. Frequently these jets are found to be adjusted into marginally stable states that support large transient growth. In this work, a comprehensive theory for the interaction of jets with turbulence, stochastic structural stability theory (SSST), is applied to the two-layer baroclinic model with the object of elucidating the physical mechanism producing and maintaining baroclinic jets, understanding how jet amplitude, structure, and spacing is controlled, understanding the role of parameters such as the temperature gradient and static stability in determining jet structure, understanding the phenomenon of abrupt reorganization of jet structure as a function of parameter change, and understanding the general mechanism by which turbulent jets adjust to marginally stable states supporting large transient growth.
When the mean thermal forcing is weak so that the mean jet is stable in the absence of turbulence, jets emerge as an instability of the coupled system consisting of the mean jet dynamics and the ensemble mean eddy dynamics. Destabilization of this SSST coupled system occurs as a critical turbulence level is exceeded. At supercritical turbulence levels the unstable jet grows, at first exponentially, but eventually equilibrates nonlinearly into stable states of mutual adjustment between the mean flow and turbulence. The jet structure, amplitude, and spacing can be inferred from these equilibria.
With weak mean thermal forcing and weak but supercritical turbulence levels, the equilibrium jet structure is nearly barotropic. Under strong mean thermal forcing, so that the mean jet is unstable in the absence of turbulence, marginally stable highly nonnormal equilibria emerge that support high transient growth and produce power-law relations between, for example, heat flux and temperature gradient. The origin of this power-law behavior can be traced to the nonnormality of the adjusted states.
As the stochastic excitation, mean baroclinic forcing, or the static stability are changed, meridionally confined jets that are in equilibrium at a given meridional wavenumber abruptly reorganize to another meridional wavenumber at critical values of these parameters.
The equilibrium jets obtained with this theory are in remarkable agreement with equilibrium jets obtained in simulations of baroclinic turbulence, and the phenomenon of discontinuous reorganization of confined jets has important implications for storm-track reorganization and abrupt climate change.
Tropical Atlantic Variability Modes (1979–2002). Part II: Time-Evolving Atmospheric Circulation Related to SST-Forced Tropical Convection
Authors: García-Serrano Javier , Losada Teresa , Rodríguez-Fonseca Belén , Polo Irene 
Published: May 2008

Abstract
The ways in which deep convection over the tropical Atlantic affects the midlatitude climate variability through meridional circulation, planetary wave teleconnection, and wave–mean flow interaction is examined for the 1979–2002 period, by following the North Atlantic anomalous rainfall evolution from summer to late winter. In this way, the first two covariability modes between anomalous summer tropical Atlantic sea surface temperature (SST) and anomalous summer–late-winter precipitation over the North Atlantic basin are analyzed using the same methodology of extended maximum covariance analysis developed for Part I. This work updates the results given by other authors, whose studies are based on different datasets dating back to the 1950s. To this end, the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) dataset, which includes measures over the ocean, is used to give a complete picture of the interannual rainfall patterns for the last decades.
The first mode, which accounts for more than 40% of the squared covariance fraction (SCF), involves SST anomalies related to the equatorial mode or Atlantic Niño. Its atmospheric response shows variations of the Atlantic Hadley and Ferrel circulations, reinforcing the direct and indirect circulation cells, respectively, displacements of the Atlantic Walker circulation, and the excitation of Rossby waves, which are trapped in the North African–Asian jet. The second mode, which accounts for 15% of the SCF, is associated with the summer horseshoe and winter tripole SST patterns. The related atmospheric circulation anomalies include direct thermal forcing (altering the local Hadley cell), perturbations in the ITCZ, and wavelike responses from the Caribbean region.
The method used in this work highlights the seasonal dependence of the modes, in contrast to previous work that neglects to take into account the month-to-month evolution of these modes. The results add new and valuable information to the understanding of these modes from the important period back to the 1980s.
An Improved Parameterization for Simulating Arctic Cloud Amount in the CCSM3 Climate Model
Authors: Vavrus Steve , Waliser Duane 
Published: May 2008

Abstract
A simple alternative parameterization for predicting cloud fraction in the Community Climate System Model, version 3 (CCSM3) global climate model is presented. This formula, dubbed “freeezedry,” is designed to alleviate the bias of excessive low clouds during polar winter by reducing the cloud amount under very dry conditions. During winter, freezedry decreases the low cloud amount over the coldest regions in high latitudes by over 50% locally and more than 30% averaged across the Arctic. The cloud reduction causes an Arctic-wide drop of 15 W m−2 in surface cloud radiative forcing (CRF) during winter and about a 50% decrease in mean annual Arctic CRF. Consequently, wintertime surface temperatures fall by up to 4 K on land and 2–8 K over the Arctic Ocean, thus significantly reducing the model’s pronounced warm bias. Freezedry also affects CCSM3’s sensitivity to greenhouse forcing. In a transient-CO2 experiment, the model version with freezedry warms up to 20% less in the North Polar and South Polar regions (1.5- and 0.5-K-smaller warming, respectively). Paradoxically, the muted high-latitude response occurs despite a much larger increase in cloud amount with freezedry during nonsummer months (when clouds warm the surface), apparently because of the colder modern reference climate. While improving the polar climate simulation in CCSM3, freezedry has virtually no influence outside of very cold regions and has already been implemented in another climate model, the Global Environmental and Ecological Simulation of Ecological Systems, version 1 (GENESIS1). Furthermore, the simplicity of this parameterization allows it to be readily incorporated into other GCMs, many of which also suffer from excessive wintertime polar cloudiness.
Lagrangian H/U3 Values Computed around Fronts Using a Fine-Resolution Numerical Model and Ferryboat-Monitored SST Dataset
Authors: Sun Youn-Jong , Isobe Atsuhiko 
Published: May 2008

Abstract
Front locations are identified as the local maximum of the sea surface temperature gradient revealed in the continuously ferryboat-monitored data in the Seto Inland Sea, Japan. In addition, Simpson and Hunter’s H/U3 values, where H is the water depth and U is the tidal-current amplitude, are computed at each cell using a fine-resolution, finite-volume ocean model to find the values at the fronts (i.e., Eulerian critical H/U3 values). Moreover, Lagrangian critical H/U3 values are computed using the same model in conjunction with particle-tracking experiments in which the particle’s H/U3 values saved along their trajectories are all averaged at each cell. In comparison with the Eulerian H/U3 values, it is revealed that the standard deviation of the Lagrangian critical values considerably reduces, especially for the fronts near straits. This accurate estimate of the critical H/U3 values shows that critical values depend on the tidal-current amplitude at the front locations. The dependency of critical H/U3 values on the tidal-current amplitude is likely due to dependency of the efficiency factor for vertical mixing in the original Simpson and Hunter formula on the amplitude. It is suggested that the efficiency factor for vertical mixing must be small (large) at locations with the large (small) tidal-current amplitude.
Vortex Interactions and Barotropic Aspects of Concentric Eyewall Formation
Authors: Kuo Hung-Chi , Schubert Wayne H. , Tsai Chia-Ling , Kuo Yu-Fen 
Published: May 2008

AbstractConcentric eyewall formation can be idealized as the interaction of a tropical cyclone core with nearby weaker vorticity of various spatial scales. This paper considers barotropic aspects of concentric eyewall formation from modified Rankine vortices. In this framework, the following parameters are found to be important in concentric eyewall formation: vorticity strength ratio, separation distance, companion vortex size, and core vortex skirt parameter. A vorticity skirt on the core vortex affects the filamentation dynamics in two important ways. First, the vorticity skirt lengthens the filamentation time, and therefore slows moat formation in the region just outside the radius of maximum wind. Second, at large radii, a skirted core vortex induces higher strain rates than a corresponding Rankine vortex and is thus more capable of straining out the vorticity field far from the core. Calculations suggest that concentric structures result from binary interactions when the small vortex is at least 4–6 times as strong as the larger companion vortex. An additional requirement is that the separation distance between the edges of the two vortices be less than 6–7 times the smaller vortex radius. Broad moats form when the initial companion vortex is small, the vorticity skirt outside the radius of maximum wind is small, and the strength ratio is large. In concentric cases, an outer vorticity ring develops when the initial companion vortex is large, the vorticity skirt outside the radius of maximum wind is small, and the strength ratio is not too large. In general, when the companion vortex is 3 times as strong as the core vortex and the separation distance is 4–6 times the radius of the smaller vortex, a core vortex with a vorticity skirt produces concentric structures. In contrast, a Rankine vortex produces elastic interaction in this region of parameter space. Thus, a Rankine vortex of sufficient strength favors the formation of a concentric structure closer to the core vortex, while a skirted vortex of sufficient strength favors the formation of concentric structures farther from the core vortex. This may explain satellite microwave observations that suggest a wide range of radii for concentric eyewalls.
Bayesian Model Averaging’s Problematic Treatment of Extreme Weather and a Paradigm Shift That Fixes It
Authors: Bishop Craig H. , Shanley Kevin T. 
Published: May 2008

Abstract
Methods of ensemble postprocessing in which continuous probability density functions are constructed from ensemble forecasts by centering functions around each of the ensemble members have come to be called Bayesian model averaging (BMA) or “dressing” methods. Here idealized ensemble forecasting experiments are used to show that these methods are liable to produce systematically unreliable probability forecasts of climatologically extreme weather. It is argued that the failure of these methods is linked to an assumption that the distribution of truth given the forecast can be sampled by adding stochastic perturbations to state estimates, even when these state estimates have a realistic climate. It is shown that this assumption is incorrect, and it is argued that such dressing techniques better describe the likelihood distribution of historical ensemble-mean forecasts given the truth for certain values of the truth. This paradigm shift leads to an approach that incorporates prior climatological information into BMA ensemble postprocessing through Bayes’s theorem. This new approach is shown to cure BMA’s ill treatment of extreme weather by providing a posterior BMA distribution whose probabilistic forecasts are reliable for both extreme and nonextreme weather forecasts.
Unheard Voices: Themes Emerging From Studies of the Views About School Engagement of Young People With High Support Needs in the Area of Mental Health
Authors: Holdsworth Roger , Blanchard Michelle 
Published: May 2008

AbstractWe know that students' positive engagement with school is closely linked to their positive mental health. In particular, a positive engagement assists students to develop the human connections and resilience that reduces the risk of developing later mental health problems. What do students themselves say about what assists them to engage successfully with school? In particular, what is known of the views of students with high support needs in the area of mental health? The MindMatters Plus Project commissioned a review of existing studies of students' perspectives about engagement. This overview summarises the literature that typifies the three overlapping areas of school engagement, student voice and students with high support needs in the area of mental health, drawing on an extensive annotated bibliography of sources (available online at mmplus.agca.com.au/studeng_unheard_voices.php?x=13). The students about whom MindMatters Plus has a particular concern — those who are at greater risk of having high support needs in the area of mental health — are often less likely to voice their opinion and concerns to adults. As a consequence, less is known about what they are saying about factors that engage them with school — theirs are frequently ‘unheard voices’.
The Prevention of Depression in 8- to 9-Year-Old Children: A Pilot Study
Authors: Rooney Rosanna , Roberts Clare , Kane Robert , Pike Lisbeth , Winsor Amber , White Julia , Brown Annette 
Published: May 2008

AbstractThe outcomes of a new universal program aimed at preventing depressive symptoms and disorders in 8- to 9-year-old children are presented. The Positive Thinking Program is a mental health promotion program based on cognitive and behavioural strategies. It is designed to meet the developmental needs of children in the middle primary school Years 4 and 5. Four state primary schools were randomly assigned to receive the program implemented by psychologists or to a control condition involving their regular Health Education curriculum. Seventy-two children participated in the intervention condition and 48 children in the control condition. Children completed measures of depressive and anxiety symptomatology, depressive disorders, and attribution style. The intervention was associated with reductions in depressive symptoms and more positive attributions at post-intervention. Compared to the control group, there was a lower prevalence of depressive disorders at posttest and fewer intervention group children developed a depressive disorder at a 9-month follow-up.
Corrosion and Oxide Properties of HANA Alloys
Authors: Park Jeong-Yong , Choi Byung-Kwon , Jo Yoo Seung , Hwan Jeong Yong 
Published: May 2008

Abstract
The corrosion behavior of HANA alloys has been investigated at 360°C in a pure water autoclave as well as in a pressurized water reactor (PWR)-simulating loop. The grain morphology and the incorporated precipitates of the oxide were characterized to elucidate the corrosion mechanism of HANA alloys. HANA alloys showed a much lower corrosion rate when compared to Zircaloy-4 in the investigated corrosion environments with HANA-6 (Zr-1.1Nb-0.05Cu), revealing a lower corrosion rate than HANA-4 (Zr-1.5Nb-0.4Sn-0.2Fe-0.1Cr). The corrosion rate was increased with an increase of the final annealing temperature of the alloys and the dissolved oxygen content in the corrosion environment. The oxide grain morphology of the HANA alloys was changed periodically from equiaxed grains to columnar ones during its growth to form a layered structure of the oxide. The change of the oxide grain morphology correlated well with the transition of the corrosion kinetics. It was revealed that the fully developed layer was thicker and the columnar grain size was larger in the protective oxide with a lower corrosion rate. The precipitates of HANA alloys were more finely distributed and oxidized more slowly in the oxide when compared to those of Zircaloy-4. Such oxidation characteristics of the precipitates along with the reduction of the Sn content were considered to be more favorable for growing an oxide to a greater thickness before transition and increasing the columnar grain size of the oxide, thereby improving the corrosion resistance of HANA alloys.
Experimental Estimation of J-R Curves from Load-CMOD Record for SE(B) Specimens
Authors: Zhu Xian-Kui , Leis Brian N. , Joyce James A. 
Published: May 2008

Abstract
Fracture resistance of ductile materials is often characterized by a J-R curve, and measured using the fracture toughness testing standard ASTM E1820 (Standard Test Method for Measurement of Fracture Toughness). The recommended elastic unloading compliance method or resistance curve test method requires simultaneous measurements of applied load (P), load-line displacement (LLD), and crack-mouth opening displacement (CMOD) from a single test for the single-edge notched bend [SE(B)] specimen. The P-CMOD record is used to determine crack extension, and the P-LLD record in conjunction with the crack extension is used to calculate the J-integral. However, it is well known that while highly accurate CMOD measurements can be made, the measurement of LLD is less accurate and more difficult because of transducer mounting difficulties, specimen load point indentions and load train deflections, or a combination thereof. Extensive finite element analyses showed that the LLD-based J equation may give inaccurate results for a shallow-cracked SE(B) specimen because its geometry factor η may depend on the strain hardening exponent. In contrast for the same geometry, the CMOD-based η factor is insensitive to the hardening exponent, and thus a CMOD-based J equation could be more accurate to be used in the determination of J-R curves. Based on the energy principle, this paper proposes a CMOD-based J equation for a growing crack using an incremental function similar to the present ASTM E1820-06 formulation that is applicable to the J calculations for a J-R curve testing. The proposed CMOD-based J formulation contains two geometry factors, i.e., CMOD-based η and γ, and can consider the crack growth correction. The solutions of four geometry factors are presented for the SE(B) specimens with a wide range of crack length. The proposed formulation is then applied to determine J-R curves for HY80 steel using the load-CMOD record for SE(B) specimens, and the results are compared with those using the traditional LLD-based formulation. The comparison shows close agreement between these two formulations. It is recommended that the proposed formulation be used in ASTM E1820 to determine more accurate J-R curves and reduce test costs as well.
Erythropoietin Receptors on Tumor Cells: What Do They Mean?
Authors: Fandrey Joachim 
Published: May 2008

Abstract
Given the apparent presence of erythropoietin receptors (EPORs) in cancer tissues, questions have been raised about the possible influence of erythropoiesis-stimulating agents (ESAs) on tumor growth and proliferation. Preclinical studies of ESAs have shown no greater tumor proliferation in cell lines and no adverse effect on treatment outcomes in animal models. Furthermore, it appears that the commercially available antibodies that have been used in clinical studies are not specific to EPORs. In particular, they detect isoforms of heat shock protein 70, which is found in tumor cells and is associated with poor prognosis. For this reason, results from clinical studies purporting to relate the administration of ESAs to shorter survival must be considered inconclusive and complicated by methodological and sampling issues. Ongoing studies will help clarify whether the existence of the EPOR has any relevance at all in the cancer setting.
Safety Update on Erythropoiesis-Stimulating Agents: Trials Within and Outside the Accepted Indications
Authors: Gascón Pere 
Published: May 2008

Abstract
Certain studies in which erythropoiesis-stimulating agents (ESAs) have been given not with the aim of correcting anemia but to achieve higher target levels of hemoglobin have shown significantly poorer survival among treated patients. However, studies in which ESAs were administered with the aim of reducing the need for RBC transfusions in patients with chemotherapy-associated anemia demonstrate that the use of these agents is not associated with any adverse effect on survival when compared with placebo controls. We can therefore be reassured that using ESAs within the labeled indications will not adversely affect patient outcome.
Heavy metal accumulation of Danube river aquatic plants — indication of chemical contamination
Authors: Pajević Slobodanka , Borišev Milan , Rončević Srđan , Vukov Dragana , Igić Ružica 
Published: May 2008

Abstract
In this paper, the ecological status of a section of the Danube River flowing through Serbia from Bezdan to Djerdap was evalutated. Using the chemical composition of water, sediment samples from the littoral zone and dominant aquatic macrophytes, the level of chemical pollution was ascertained. Chemical analyses of the water and sediment indicated that the tributaries flowing into the Danube significantly influenced the chemical load of the water and as a direct consequence, the sediment. The concentration of heavy metals including Cu, Mn and Cd found in plants of the Potamogeton genus, further indicated significant chemical pollution, establishing a clear link between the chemical composition of plant tissues and the chemical composition of water and sediment. This paper therefore describes how the chemical composition of aquatic plants can be used as a reliable indicator for heavy metal pollution of aquatic ecosystems.
Correlation of low molecular weight advanced glycation end products and nitric oxide metabolites with chronic complications in type 1 diabetic patients
Authors: Heltianu Constantina , Manea Simona-Adriana , Guja Cristian , Mihai Carina , Ionescu-Tirgoviste Constantin 
Published: May 2008

Abstract
Advanced glycation end products (AGEs) are involved in the occurrence of vascular complications in diabetes. The present study was undertaken to investigate the level of low-molecular weight products of AGEs (LMW-AGEs) in relation to microvascular complications in type 1 diabetes, and the possible relationship with nitric oxide (NO) as a marker of endothelial function. Patients with normal renal function (NRF) were classified into two groups: (1) without, and (2) with diabetic neuropathy; and patients with renal impairment also into two groups: (3) diabetic renal disease, and (4) end-stage renal disease. The fluorescence of LMW-AGEs and measurement of NO metabolites was assessed in 277 serum samples. In addition, multiple regression analysis was performed. In group 1, LMW-AGEs level (9.3±1.1 AF%) was higher than in the control group (2.4±0.3 AF%). A trend in the increase of LMW-AGEs with neuropathy (29.7±5.5 AF%, group 2), and further with renal impairment (47.0±8.0, group 3 and 137.8±25.5 AF%, group 4), was observed. In multivariate regression analysis LMW-AGEs were associated with NO metabolites in group 2. In NRF patients, diabetic neuropathy was significantly correlated with LMW-AGEs and NO metabolites, independently of serum creatinine and duration of diabetes. This relationship suggests that the NO and LMW-AGEs’ actions (possibly synergistic) in endothelial activation possess a role in the initiation and development of diabetic microvascular complications.