bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parameterization of Cloud Microphysics Based on Full Integral Moments
Authors: Kogan Yefim L. , Belochitski Alexei 
Published: March 2012

Abstract
This paper describes a microphysics parameterization based on integral moments of the full drop size distributions (DSDs) as opposed to a partial moments approach (sometimes referred to as Kessler-type parameterization) based on the moments integrated separately over the cloud and rain drop portion of the drop spectrum. This approach does not assume a prescribed form of a DSD but employs as model variables full moments that have clear physical meaning: drop concentration and surface area, water content, precipitation flux, and radar reflectivity. These variables can be directly measured and assimilated into the model forecast cycle without intermediate retrievals. The approach avoids division of DSDs into cloud and rain drops. This eliminates the problem of defining the threshold between these two categories and subdivision of the physical coagulation process into artificial processes of autoconversion, accretion, and self-collection. The development and testing of the parameterization was made using the Cooperative Institute for Mesoscale Meteorological Studies (CIMMS) large-eddy simulation (LES) explicit warm rain microphysical model. The conversion and sedimentation rates were parameterized in the form of a product of power functions using nonlinear regression analysis to determine exponents of the approximated expressions. The comparison of bulk and explicit microphysics models demonstrated reasonably good prediction of both thermodynamic and microphysical parameters of the stratocumulus-topped boundary layer (STBL). The weaknesses and problems of the numerical implementation of the full moment approach are also discussed.
Uncertainties in Hydrologic and Climate Change Impact Analyses in Headwater Basins of British Columbia
Authors: Bennett Katrina E. , Werner Arelia T. , Schnorbus Markus 
Published: March 2012

Abstract
Three headwater basins located across British Columbia (BC) were analyzed using a hydrologic model driven by five global climate models (GCMs) and three scenarios from the Special Report on Emissions Scenarios (SRES) to project future changes in seasonal water budgets and assess the uncertainty in the projections arising from GCMs, emissions scenarios, and hydrologic model parameterizations under two future time periods. Future projected changes in temperature are for annual increases of approximately +2°C by the 2050s and +3°C by the 2080s. The 2050s and 2080s precipitation projections are for increased winter precipitation in all basins and decreases in summertime precipitation for two of the three basins—with increases projected in the northeastern BC subwatershed. The study found that the hydrologic parameter uncertainty ranged up to 55%, (average 31%) for winter runoff anomalies, which was less than the uncertainty associated with GCMs and emissions scenarios that ranged up to 135% and 78% (average 84% and 58%, respectively). The uncertainty results were variable across the three hydroclimate regimes. Coastal headwater systems in British Columbia experience more uncertainty associated with changes during winter and the summer, whereas interior systems experience the greatest uncertainties during the winter and spring. Changes projected for the 2050s at the coastal site fell outside of the range of natural variability, a robust shift that may result in a very different regime for this basin within the short planning horizon of 50 years. A small, semiarid watershed located on the Chilcotin Plateau exhibited changes to the hydrologic regime that were projected to be small in absolute terms and fell within the range of natural variability.
Mid-Twenty-First-Century Changes in Extreme Events over Northern and Tropical Africa
Authors: Vizy Edward K. , Cook Kerry H. 
Published: March 2012

Abstract
Changes in rainfall and temperature extremes are predicted by many global climate models as a response to greenhouse gas increases, and such changes will have significant environmental and social impacts. A regional climate model is used to predict changes in extremes across tropical and northern Africa for 2041–60 under a midline emissions forcing scenario. Six indicators are examined, including annual extreme and daily diurnal temperature ranges, heat wave days, number of dry days, number of extreme wet days, and extreme wet day rainfall intensity. Confidence in the projections is evaluated by examining the ensemble spread and the validation of extreme events in the twentieth-century simulation.
Despite an increase in both daily minimum and maximum temperatures, diurnal temperature ranges decrease from West Africa to Ethiopia during spring and fall, over the Sahel during summer, and over the Congo basin during winter and spring. Diurnal temperature ranges increase over the Horn of Africa during boreal winter and over Kenya and Tanzania during boreal summer. The number of heat wave days increases north of 8°N with the largest increase (60–120 days) over the western Sahel. The number of dry days decreases over the Congo and the central Sahel but increases over East Africa, the latter associated with a reduction in the springtime long rains. The number of extreme wet rainfall days is projected to increase over West Africa, the Sahel, and the Ethiopian Highlands but decrease over the Congo. The predicted changes in extreme wet rainfall intensity are highly regional.
Turbulent Kinetic Energy Dissipation in Barrow Canyon
Authors: Shroyer E. L. 
Published: March 2012

Abstract
Pacific Water flows across the shallow Chukchi Sea before reaching the Arctic Ocean, where it is a source of heat, freshwater, nutrients, and carbon. A substantial portion of Pacific Water is routed through Barrow Canyon, located in the northeast corner of the Chukchi. Barrow Canyon is a region of complex geometry and forcing where a variety of water masses have been observed to coexist. These factors contribute to a dynamic physical environment, with the potential for significant water mass transformation. The measurements of turbulent kinetic energy dissipation presented here indicate diapycnal mixing is important in the upper canyon. Elevated dissipation rates were observed near the pycnocline, effectively mixing winter and summer water masses, as well as within the bottom boundary layer. The slopes of shear/stratification layers, combined with analysis of rotary spectra, suggest that near-inertial wave activity may be important in modulating dissipation near the bottom. Because the canyon is known to be a hotspot of productivity with an active benthic community, mixing may be an important factor in maintenance of the biological environment.
Mapping GPS Radio Occultation Data by Bayesian Interpolation
Authors: Leroy Stephen S. , Ao Chi O. , Verkhoglyadova Olga 
Published: March 2012

Abstract
Bayesian interpolation for mapping GPS radio occultation data on a sphere is explored and its performance evaluated. Bayesian interpolation is ideally suited to the task of fitting data randomly and nonuniformly distributed with unknown error without overfitting the data. The geopotential height at dry pressure 200 hPa is simulated as data with theoretical distributions of the Challenging Mini-Satellite Payload (CHAMP) and of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC). The simulated CHAMP data are found to be best fit with a spherical harmonic basis of 14th degree; the COSMIC data with a spherical harmonic basis of 20th degree. The best regularizer mimics a spline fit, and relaxing the penalty for purely meridional structures or for the global mean yields little advantage. Climatologies are most accurately established by binning in ≃2-day intervals to best resolve synoptic structures in space and time. Finally, Bayesian interpolation is shown to negate a source of systematic sampling error obtained in binning and averaging highly nonuniform data but to incur another systematic error due to incomplete resolution of the background atmosphere, notably in the Southern Hemisphere.
The Gradient Velocity Track Display (GrVTD) Technique for Retrieving Tropical Cyclone Primary Circulation from Aliased Velocities Measured by Single-Doppler Radar
Authors: Wang Mingjun , Zhao Kun , Lee Wen-Chau , Jou Ben Jong-Dao , Xue Ming 
Published: March 2012

Abstract
The ground-based velocity track display (GBVTD) technique was developed to estimate the primary circulations of landfalling tropical cyclones (TCs) from single-Doppler radar data. However, GBVTD cannot process aliased Doppler velocities, which are often encountered in intense TCs. This study presents a new gradient velocity track display (GrVTD) algorithm that is essentially immune to the Doppler velocity aliasing. GrVTD applies the concept of gradient velocity–azimuth display (GVAD) to the GBVTD method. A GrVTD-simplex algorithm is also developed to accompany GrVTD as a self-sufficient algorithm suite.
The results from idealized experiments demonstrate that the circulation center and winds retrieved from GrVTD with aliased velocity and GBVTD with dealiased velocity are in good agreement, but GrVTD is more sensitive to random observation errors. GrVTD was applied to Hurricane Charley (2004) where the majority of the Doppler velocities of the inner-core region were aliased. The GrVTD-retrieved circulation pattern and magnitude are nearly identical to those retrieved in GBVTD with manually dealiased velocities. Overall, the performance of GrVTD is comparable but is more sensitive to the data distribution than that of the original GBVTD using dealiased velocity. GrVTD can be used as a preprocessor for dealiasing velocity in TCs before the data are used in GBVTD or other algorithms.
Layered titanosilicates
Authors: Lin Zhi , Paz Filipe A. Almeida , Rocha Joāo 
Published: March 2012

Abstract
Layered materials have much potential for applications as ion exchangers, gas sorbents and catalysts. Layered titanosilicates are of particular interest because on the one hand they possess large amounts of titanium and, on the other, they exhibit a wide variety of crystal structures. This chapter summarizes the main structural features in the family of heteropolyhedral layered titanosilicates and presents briefly the synthesis and application studies on some of these materials. The most representative members have been described in terms of the construction of each individual sheet from the individual building blocks. In general, the structures of these materials encompass single layers, micatype layers (heterophyllosilicates) and perforated ‘microporous’ layers. The most commonly used synthesis process and potential applications of some layered titanosilicates are reviewed briefly. The materials with perforated ‘microporous’ sheets are particularly interesting because they can be considered as microporous materials with one of the dimensions in the nano size regime, meaning the materials have fast transport properties. Most of the structures reviewed are known only as minerals. Both the synthesis and potential applications of layered titanosilicates have been significantly underexplored and still present a great number of challenges and opportunities for future research.
Intercalation processes of layered minerals
Authors: Bergaya Faïza , Lagaly Gerhard 
Published: March 2012

AbstractUnderstanding clay mineral intercalation is the aim of this chapter. Intercalation, which corresponds to a reversible inclusion of different species between two layers, depends on the geometrical, physical and chemical characteristics of each type of clay mineral.In most phyllosilicates, the interlayer space is occupied by cations which are more or less hydrated. These water molecules which separate two successive layers enable further intercalation reactions by physical adsorption or by chemical grafting of a great variety of species. It is noteworthy that intercalation of inorganic or organic species by ion exchange of these interlayer cations is often the first step in intercalation and is of primary importance in much basic and applied research of the modified clay minerals obtained. This concerns organo-clay minerals (OC), pillared clays (PILC) and clay mineral-polymer nanocomposites (CPN). In non-swelling clay minerals where, generally, the interlayer space is empty, the layers are held by van der Waals interactions or by hydrogen bonds between the stacked layers. In this case, different mechanisms of intercalation can occur and are described.X-ray diffraction (XRD) and adsorption methods, which induce swelling, and how they are used to confirm intercalation are described below. The meanings of the commonly used terms ‘intercalated’ and ‘exfoliated structures’ in CPN literature and the meanings of the confusing terms, ‘exfoliation’ and ‘delamination’, are also discussed.When the reversibility of the intercalation can be controlled, applications become possible. In conclusion, this chapter aims to draw attention to the importance of the geo-metrical arrangement of the different clay mineral units in predicting their properties. The unique intercalation property of clay minerals allows us to consider possible further development in aid of our environment, our health and our wellbeing.
Trace inequalities for positive semidefinite matrices with centrosymmetric structure
Authors: Zhao Di , Li Hongyi , Gong Zhiguo 
Published: March 2012

Abstract
In this article, we present some results on the Hadamard product of positive semidefinite matrices with centrosymmetric structure. Based on these results, several trace inequalities on positive semidefinite centrosymmetric matrices are obtained.
Association of single nucleotide polymorphic sites in candidate genes with aggressiveness and deoxynivalenol production in Fusarium graminearum causing wheat head blight
Authors: Talas Firas , Würschum Tobias , Reif Jochen C , Parzies Heiko K , Miedaner Thomas 
Published: March 2012

Abstract

Background

Fusarium graminearum sensu stricto (s.s.) is an ubiquitous pathogen of cereals. The economic impact of Fusarium head blight (FHB) is characterized by crop losses and mycotoxin contamination. Our objective was to associate SNP diversity within candidate genes with phenotypic traits. A total of 77 F. graminearum s.s. isolates was tested for severity of fungal infection (= aggressiveness) and deoxynivalenol (DON) production in an inoculated field experiment at two locations in each of two years. For seven genes known to control fungal growth (MetAP1, Erf2) or DON production (TRI1, TRI5, TRI6 TRI10 and TRI14) single nucleotides polymorphic sites (SNPs) were determined and evaluated for the extent of linkage disequilibrium (LD). Associations of SNPs with both phenotypic traits were tested using linear mixed models.

Results
Decay of LD was in most instances fast. Two neighboring SNPs in MetAP1 and one SNP in Erf2 were significantly (P < 0.05) associated with aggressiveness explaining proportions of genotypic variance (p

G
) of 25.6%, 0.5%, and 13.1%, respectively. One SNP in TRI1 was significantly associated with DON production (p

G
= 4.4).

Conclusions
We argue that using the published sequence information of Fusarium graminearum as a template to amplify comparative sequence parts of candidate genes is an effective method to detect quantitative trait loci. Our findings underline the potential of candidate gene association mapping approaches to identify functional SNPs underlying aggressiveness and DON production for F. graminearum s.s populations.
Alternative sigma factor σH activates competence gene expression in Lactobacillus sakei
Authors: Schmid Solveig , Bevilacqua Claudia , Crutz-Le Coq Anne-Marie 
Published: March 2012

Abstract

Background
Alternative sigma factors trigger various adaptive responses. Lactobacillus sakei, a non-sporulating meat-borne bacterium, carries an alternative sigma factor seemingly orthologous to σH of Bacillus subtilis, best known for its contribution to the initiation of a large starvation response ultimately leading to sporulation. As the role of σH-like factors has been little studied in non-sporulating bacteria, we investigated the function of σH in L. sakei.

Results
Transcription of sigH coding for σH was hardly affected by entry into stationary phase in our laboratory conditions. Twenty-five genes potentially regulated by σH in L. sakei 23 K were revealed by genome-wide transcriptomic profiling of sigH overexpression and/or quantitative PCR analysis. More than half of them are involved in the synthesis of a DNA uptake machinery linked to genetic competence, and in DNA metabolism; however, σH overproduction did not allow detectable genetic transformation. σH was found to be conserved in the L. sakei species.

Conclusion
Our results are indicative of the existence of a genetic competence state activated by σH in L. sakei, and sustain the hypothesis that σH-like factors in non sporulating Firmicutes share this common function with the well-known ComX of naturally transformable streptococci.
Protein kinase CK2 localizes to sites of DNA double-strand break regulating the cellular response to DNA damage
Authors: Olsen Birgitte B , Wang Shih-Ya , Svenstrup Tina H , Chen Benjamin PC , Guerra Barbara 
Published: March 2012

Abstract

Background
The DNA-dependent protein kinase (DNA-PK) is a nuclear complex composed of a large catalytic subunit (DNA-PKcs) and a heterodimeric DNA-targeting subunit Ku. DNA-PK is a major component of the non-homologous end-joining (NHEJ) repair mechanism, which is activated in the presence of DNA double-strand breaks induced by ionizing radiation, reactive oxygen species and radiomimetic drugs. We have recently reported that down-regulation of protein kinase CK2 by siRNA interference results in enhanced cell death specifically in DNA-PKcs-proficient human glioblastoma cells, and this event is accompanied by decreased autophosphorylation of DNA-PKcs at S2056 and delayed repair of DNA double-strand breaks.

Results
In the present study, we show that CK2 co-localizes with phosphorylated histone H2AX to sites of DNA damage and while CK2 gene knockdown is associated with delayed DNA damage repair, its overexpression accelerates this process. We report for the first time evidence that lack of CK2 destabilizes the interaction of DNA-PKcs with DNA and with Ku80 at sites of genetic lesions. Furthermore, we show that CK2 regulates the phosphorylation levels of DNA-PKcs only in response to direct induction of DNA double-strand breaks.

Conclusions
Taken together, these results strongly indicate that CK2 plays a prominent role in NHEJ by facilitating and/or stabilizing the binding of DNA-PKcs and, possibly other repair proteins, to the DNA ends contributing to efficient DNA damage repair in mammalian cells.
Betalain production is possible in anthocyanin-producing plant species given the presence of DOPA-dioxygenase and L-DOPA
Authors: Harris Nilangani N , Javellana John , Davies Kevin M , Lewis David H , Jameson Paula E , Deroles Simon C , Calcott Kate E , Gould Kevin S , Schwinn Kathy E 
Published: March 2012

Abstract

Background
Carotenoids and anthocyanins are the predominant non-chlorophyll pigments in plants. However, certain families within the order Caryophyllales produce another class of pigments, the betalains, instead of anthocyanins. The occurrence of betalains and anthocyanins is mutually exclusive. Betalains are divided into two classes, the betaxanthins and betacyanins, which produce yellow to orange or violet colours, respectively. In this article we show betalain production in species that normally produce anthocyanins, through a combination of genetic modification and substrate feeding.

Results
The biolistic introduction of DNA constructs for transient overexpression of two different dihydroxyphenylalanine (DOPA) dioxygenases (DODs), and feeding of DOD substrate (L-DOPA), was sufficient to induce betalain production in cell cultures of Solanum tuberosum (potato) and petals of Antirrhinum majus. HPLC analysis showed both betaxanthins and betacyanins were produced. Multi-cell foci with yellow, orange and/or red colours occurred, with either a fungal DOD (from Amanita muscaria) or a plant DOD (from Portulaca grandiflora), and the yellow/orange foci showed green autofluorescence characteristic of betaxanthins. Stably transformed Arabidopsis thaliana (arabidopsis) lines containing 35S: AmDOD produced yellow colouration in flowers and orange-red colouration in seedlings when fed L-DOPA. These tissues also showed green autofluorescence. HPLC analysis of the transgenic seedlings fed L-DOPA confirmed betaxanthin production.

Conclusions
The fact that the introduction of DOD along with a supply of its substrate (L-DOPA) was sufficient to induce betacyanin production reveals the presence of a background enzyme, possibly a tyrosinase, that can convert L-DOPA to cyclo-DOPA (or dopaxanthin to betacyanin) in at least some anthocyanin-producing plants. The plants also demonstrate that betalains can accumulate in anthocyanin-producing species. Thus, introduction of a DOD and an enzyme capable of converting tyrosine to L-DOPA should be sufficient to confer both betaxanthin and betacyanin production to anthocyanin-producing species. The requirement for few novel biosynthetic steps may have assisted in the evolution of the betalain biosynthetic pathway in the Caryophyllales, and facilitated multiple origins of the pathway in this order and in fungi. The stably transformed 35S: AmDOD arabidopsis plants provide material to study, for the first time, the physiological effects of having both betalains and anthocyanins in the same plant tissues.