bluuebunny/crossref_metadata_2025 huggingface dataset:
Tight‐binding model for the electronic and optical properties of nitride‐based quantum dots
Authors: Schulz S. , Mourad D. , Schumacher S. , Czycholl G.
Published: July 2011

Two slightly different, efficient tight‐binding (TB) models for the description of the electronic properties of nitride‐based semiconductor quantum dots (QDs) have been developed and applied to the calculation of the electronic one‐particle spectrum of these structures. Using these one‐particle QD‐states, dipole and Coulomb matrix elements can be calculated, from which the optical properties of these systems can be obtained. These TB calculations have been performed for nitride‐based QDs with a cubic zincblende structure and those with a wurtzite crystal structure. In this paper, we discuss the general methodology used and the results obtained for the electronic one‐particle states and energies, for the dipole and Coulomb matrix elements, and for the excitonic optical emission and absorption spectra.
Magnetic vortex core reversal by rotating magnetic fields generated on micrometer length scales
Authors: Curcic Michael , Stoll Hermann , Weigand Markus , Sackmann Vitalij , Juellig Patrick , Kammerer Matthias , Noske Matthias , Sproll Markus , Van Waeyenberge Bartel , Vansteenkiste Arne , Woltersdorf Georg , Tyliszczak Tolek , Schütz Gisela
Published: July 2011

Unidirectional switching of the magnetic vortex core can be achieved in micron‐sized ferromagnetic platelets by excitation of the gyrotropic mode of the vortex structure with in‐plane rotating magnetic fields. Circulating fields with a switchable sense of rotation (clockwise, CW or counter clockwise, CCW) have been generated on a micrometer length scale at frequencies up to 1 GHz by two orthogonal electric RF currents with 90° phase shift flowing through crossed but not isolated striplines. Decoupling of these currents is realized by balanced symmetric RF sources. The amplitudes of the rotating magnetic fields and their spatial distributions are calculated and the stripline geometry is discussed. By taking advantage of this technique, unidirectional vortex core reversal by excitation with CW or CCW rotating magnetic fields has been observed by time resolved scanning transmission X‐ray microscopy. An area with reversed magnetization, the “dip,” was observed near the vortex core before vortex core reversal.
Antiproliferative Activity of Three Methoxylated Flavonoids Isolated from Zeyheria montana Mart. (Bignoniaceae) Leaves
Authors: Seito Leonardo Noboru , Ruiz Ana Lucia Tasca Goiz , Vendramini‐Costa Debora , Tinti Sirlene Valério , de Carvalho João Ernesto , Bastos Jairo Kenupp , Di Stasi Luiz Claudio
Published: July 2011

The present study isolated three major active flavonoids, two flavones named 4’,5,7‐trimethoxy‐luteolin (1) and 6‐hydroxy‐5,7‐dimethoxyflavone (2) and the flavanone 5‐hydroxy‐6,7‐dimethoxyflavanone (3) from Zeyheria montana dichloromethane leaf extract. Isolation and purification were conducted with the application of column chromatography and structures were assigned by spectral analysis. All compounds were evaluated for cytotoxic activities against human tumor cell lines UACC‐62 (melanoma), MCF‐7 (breast), NCI‐ADR/RES (breast expressing phenotype multiple drug resistance), 786‐0 (renal), NCI‐H460 (lung, non‐small cells), PC‐3 (prostate), OVCAR‐3 (ovarian), HT‐29 (colon) and K562 (leukemia) in vitro. All compounds were active in different degrees on several tumor cell lines and flavanone 3 showed cytotoxicity against almost all cell lines, particularly against human NCI‐ADR/RES and K562 cell lines. In conclusion, three antiproliferative compounds were isolated for the first time from Zeyheria montana and its leaves were characterized as an important source of methoxylated flavones and flavanone as potential antitumor compounds. Copyright © 2011 John Wiley & Sons, Ltd.
Delay‐dependent exponential H ∞  filtering for discrete‐time switched delay systems
Authors: Wang Dong , Shi Peng , Wang Jianliang , Wang Wei
Published: July 2011

In this paper, the problem of delay‐dependent exponential H ∞  filtering for discrete‐time switched delay systems is investigated under average dwell time switching signals. Time delay under consideration is interval time‐varying in the states. By introducing a proper factor to construct a novel Lyapunov‐Krasovskii function and using average dwell time approach, sufficient conditions for the solvability of this problem, dependent on the upper and lower bounds of time‐varying delay, are obtained in terms of linear matrix inequalities. A numerical example is presented to demonstrate the effectiveness of the developed results. Copyright © 2011 John Wiley & Sons, Ltd.
State feedback control of a class of high‐order stochastic nonlinear systems
Authors: Li Wuquan , Jing Yuanwei , Zhang Siying
Published: July 2011

This paper poses and solves a new problem of state feedback stabilization for a class of high‐order stochastic nonlinear systems in which the power order restriction and growth condition are relaxed to a more general form. Based on the ideas of the homogeneous systems theory and the adding of a power integrator technique, a state feedback controller is constructed to ensure that the equilibrium at the origin of the closed‐loop system is globally asymptotically stable in probability and that the problem of inverse optimal stabilization in probability is solved. The efficiency of the state feedback controller is demonstrated by a simulation example. Copyright © 2011 John Wiley & Sons, Ltd.
Tuning functions‐based robust adaptive tracking control of a class of nonlinear systems with time delays
Authors: Zhang Zhengqiang , Lu Junwei , Xu Shengyuan
Published: July 2011

In this paper, an adaptive backstepping tracking control scheme is proposed for a class of nonlinear state time‐varying delay systems, which are subject to parametric uncertainties and external disturbances. The bounds of the time delays and their derivatives are assumed to be unknown. Tuning functions method is exploited to construct the control law and adaptive laws. Unknown time‐varying delays are compensated by using appropriate Lyapunov–Krasovskii functional. It is shown that the proposed controller can guarantee the boundedness of all the closed‐loop signals. The tracking performance can be adjusted by choosing suitable design parameters. At the end, a simulation example is provided to illustrate the effectiveness of the design procedure. Copyright © 2011 John Wiley & Sons, Ltd.
Alcohol and men's health
Authors: Bell Steven , Britton Annie
Published: July 2011

Excessive alcohol consumption has serious implications for physical, psychological and social wellbeing, although there is inconclusive evidence of the role of alcohol in the aetiology of male‐specific disorders. Copyright © 2011 Wiley Interface Ltd
A guide to genital piercing
Authors: Anderson William R. , Summerton Duncan J. , Sharma Davendra M. , Holmes Simon A.
Published: July 2011

Healthcare professionals should be aware of the seemingly bizarre practice of genital piercing, as they may sometimes be required to manage the inevitable complications. Copyright © 2011 Wiley Interface Ltd
In vivo injectable gels for tissue repair
Authors: Hilborn Jons
Published: July 2011

The desire to reduce healthcare costs while improving outcomes drives minimally invasive methods to replacing traditional surgical procedures. Various treatments that would previously have needed open‐type surgeries can be carried out using endoscopes, catheters, and needles. These advantages have become especially obvious for tissue engineering and regenerative medicine with in vivo gel injectable nanomaterials. In this review, the state of the art in this rapidly developing field is given. This is done by contrasting functional evaluation in vitro with in vivo followed by describing (1) synthetic materials, (2) the body's own polymers, (3) polymers in nature, (4) self‐assembled peptides, and (5) new innovations and combinations. With increased understanding of the relationship between material characteristics and the outcome in vivo more rational design criteria are emerging . WIREs Nanomed Nanobiotechnol 2011 3 589–606 DOI: 10.1002/wnan.91

This article is categorized under:

Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement
Subjective well-being in European countries—on the age-specific impact of physical activity
Authors: Pawlowski Tim , Downward Paul , Rasciute Simona
Published: July 2011

As an attempt to measure the ‘experienced’ utility of individuals in economics, the investigation of individuals’ subjective well-being (SWB) was pioneered by Van Praag and Frijters (1999) and Kahneman et al. (1999). Since then, a number of studies has analysed the factors associated with SWB and policy makers are now recognising the importance of SWB as a policy target, with the implication being that one could target its factors associated with increase in the overall SWB in countries. However, despite its significance to economies, and increasing policy relevance, investigations on the impact of sport and physical activity on SWB are relatively rare [e.g. Rasciute and Downward in Kyklos 63(2):256–270, 2010]. More specifically, despite sports participation and engagement in physical activity having a strong age-specific profile (Breuer et al. in Eur Rev Aging Phys Act 7:61–70, 2010; Hinrichs et al. in Eur J Sport Soc 6(1):49–57, 2010; Mechling and Netz in European Rev Aging Physical Activity 6(2):89–97, 2009), there is no study that investigates whether the magnitude of this impact is age-specific. Consequently, this paper seeks to make a unique contribution to the existing literature by exploring the age-specific effects of physical activity on SWB for a broad cross-section of 19 European countries. Overall, the results suggest that engagement in physical activity generally contributes to the SWB of individuals on a European level but that significant age-specific differences exist.
THE GENERALIZED SYLVESTER MATRIX EQUATION, RANK MINIMIZATION AND ROTH’S EQUIVALENCE THEOREM
Authors: LIN MINGHUA , WIMMER HARALD K.
Published: July 2011

Roth’s theorem on the consistency of the generalized Sylvester equationAX−YB=Cis a special case of a rank minimization theorem.
PRODUCTS OF BASE-κ-PARACOMPACT SPACES AND COMPACT SPACES
Authors: MOU LEI
Published: July 2011

Let λ be a regular ordinal with λ≥ω1. Then we prove that (λ+1)×λ is not base-countably metacompact. This implies that base-κ-paracompactness is not an inverse invariant of perfect mappings, which answers a question asked by Yamazaki.
REVERSIBLE SKEW GENERALIZED POWER SERIES RINGS
Authors: NASR-ISFAHANI A. R.
Published: July 2011

In this note we show that there exist a semiprime ring R, a strictly ordered artinian, narrow, unique product monoid (S,≤) and a monoid homomorphism ω:S⟶End(R) such that the skew generalized power series ring R[[S,ω]] is semicommutative but R[[S,ω]] is not reversible. This answers a question posed in Marks et al. [‘A unified approach to various generalizations of Armendariz rings’, Bull. Aust. Math. Soc.81 (2010), 361–397].
BOUNDS FOR ODD k-PERFECT NUMBERS
Authors: CHEN SHI-CHAO , LUO HAO
Published: July 2011

Let k≥2 be an integer. A natural number n is called k-perfect if σ(n)=kn. For any integer r≥1, we prove that the number of odd k-perfect numbers with at most r distinct prime factors is bounded by (k−1)4r3.
Mutual interactions between an invasive bark beetle and its associated fungi
Authors: Wang B. , Salcedo C. , Lu M. , Sun J.
Published: July 2011

Interactions between invasive insects and their fungal associates have important effects on the behavior, reproductive success, population dynamics and evolution of the organisms involved. The red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Scolytinae), an invasive forest pest in China, is closely associated with fungi. By carrying fungi on specialized structures in the exoskeleton, RTB inoculates fungi in the phloem of pines (when females dig galleries for egg laying and when males join them for mating). After eggs hatch, larvae gregariously feed on the phloem colonized by the fungi. We examined the effects of five isolates of RTB associated fungi (two from North America, Leptographium terebrantis and L. procerum, and three from China, Ophiostoma minus, L. sinoprocerum and L. procerum) on larval feeding activity, development and mortality. We also studied the effects of volatile chemicals produced in the beetle hindgut on fungal growth. Ophiostoma minus impaired feeding activity and reduced weight in RTB larvae. Leptographium sinoprocerum, L. terebrantis and L. procerum did not dramatically influence larval feeding and development compared to fungi-free controls. Larval mortality was not influenced by any of the tested fungi. Hindgut volatiles of RTB larvae, verbenol, myrtenol and myrtenal, inhibited growth rate of all the fungi. Our results not only show that D. valens associated fungus, O. minus, can be detrimental to its larvae; but, most importantly, they also show that these notorious beetles have an outstanding adaptive response evidenced by the ability to produce volatiles that inhibit growth of harmful fungus.
Novel sequence types (STs) ofStaphylococcus aureusisolates causing clinical and subclinical mastitis in flocks of sheep in the northeast of Brazil
Authors: de Almeida Lara M , de Almeida Mayra Zilta PRB , de Mendonça Carla L , Mamizuka Elsa M
Published: July 2011

Staphylococcus aureusis one of the most important infectious mastitis causative agents in small ruminants. In order to know the distribution ofStaph. aureusstrains associated with infectious mastitis in flocks of sheep in the northeast of Brazil and establish whether these clones are related to the strains distributed internationally, this study analysed the genetic diversity ofStaph. aureusisolates from cases of clinical and subclinical mastitis in ewes by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). In this research, 135 ewes with mastitis from 31 sheep flocks distributed in 15 districts were examined.Staph. aureuswas isolated from sheep milk in 9 (29%) out of 31 herds located in 47% of the districts surveyed. MLST analysis allowed the identification of four STs (ST750, ST1728, ST1729 and ST1730). The last three with their respective novel alleles (glp-220;pta-182 andyqil-180) were recently reported in theStaph. aureusMLST database (http://www.mlst.net). Each novel allele showed only a nucleotide different from those already described. The occurrence of CC133 (ST750 and ST1729) in this study is in agreement with other reports that only a few clones ofStaph. aureusseem to be responsible for most cases of mastitis in dairy farms and that some of these clones may have broad geographic distribution. However, the prevalence of CC5 (ST1728 and ST1730)—an important group related to cases of colonization or infection in humans—differs from previous studies by its widespread occurrence and may suggest human contamination followed by selective pressures of the allelic diversifications presented for these STs.
Deterministic model to evaluate the impact of lactational treatment of subclinical mastitis due to coagulase-negative staphylococci
Authors: Bexiga Ricardo , Ellis Kathryn A , Vilela Cristina L , Mellor Dominic J
Published: July 2011

Coagulase-negative staphylococci (CNS) are the most frequently isolated bacteria from milk samples in several studies worldwide. Despite their relative frequency, specific measures aiming at their control are not well established. One possible measure to include in a control programme is lactational antimicrobial treatment. The decision to perform such treatment, as well as other actions on farm, should be based on the likelihood of financial return. A deterministic model was used to evaluate whether performing an antimicrobial treatment during the lactation for quarters infected with CNS was financially justifiable. Input variables for the impact of CNS on udder health were based on a previous study by the same authors and on available literature on the subject. Prices included in the model were based on 2009/2010 conditions in Portugal. The average result per antimicrobial treated quarter was a net loss of €38·74. Performing a sensitivity analysis to evaluate how systematic variation of the input variables of the model would lead to outcome changes showed that variation in input variables nearly always led to a negative outcome, with the greatest variation in losses observed for variation in the length of treatment and milk withdrawal period (−€46·26 to −€28·49). The situations in which a net benefit was to be expected included the bulk tank somatic cell count decreasing to a level corresponding to a premium payment or to penalties being avoided, and the prevention of transmission of CNS in the milking parlour when the possibility of transmission was at its highest level. For most situations, lactational treatment of CNS subclinical mastitis was not financially justifiable.
Detection of cow milk in donkey milk by chemometric procedures on triacylglycerol stereospecific analysis results
Authors: Cossignani Lina , Blasi Francesca , Bosi Ancilla , D'Arco Gilda , Maurelli Silvia , Simonetti Maria Stella , Damiani Pietro
Published: July 2011

Stereospecific analysis is an important tool for the characterization of lipid fraction of food matrices, and also of milk samples. The results of a chemical-enzymatic-chromatographic analytical method were elaborated by chemometric procedures such as linear discriminant analysis (LDA) and artificial neural network (ANN). According to the total composition and intrapositional fatty acid distribution in the triacylglycerol (TAG) backbone, the obtained results were able to characterize pure milk samples and milk mixtures with 1, 3, 5% cow milk added to donkey milk. The resulting score was very satisfactory. Totally correct classified samples were obtained when the TAG stereospecific results of all the considered milk mixtures (donkey-cow) were elaborated by LDA and ANN chemometric procedures.
Auditory and vestibular hair cell stereocilia: relationship between functionality and inner ear disease
Authors: Ciuman R R
Published: July 2011

The stereocilia of the inner ear are unique cellular structures which correlate anatomically with distinct cochlear functions, including mechanoelectrical transduction, cochlear amplification, adaptation, frequency selectivity and tuning. Their function is impaired by inner ear stressors, by various types of hereditary deafness, syndromic hearing loss and inner ear disease (e.g. Ménière's disease). The anatomical and physiological characteristics of stereocilia are discussed in relation to inner ear malfunctions.
Confucian Constitutionalism: Mencius and Xunzi on Virtue, Ritual, and Royal Transmission
Authors: Kim Sungmoon
Published: July 2011

By examining Xunzi's and Mencius's contrary reactions toward royal transmission by individual merit or “abdication” (shanrang禪讓), this article attempts to reveal the distinctive features of their respective political theories, which I reconstruct in terms oflizhiconstitutionalism anddezhiconstitutionalism. Resisting the conventional tendency to capture Mencius's and Xunzi's political theories in such dichotomous terms as idealism and realism, this paper draws attention to the complex mixture of idealism and realism found in both thinkers' constitutional political theories and identifies such common ground in terms of “Confucian constitutionalism.” This paper presents Mencius's idealistic defense of abdication and his realistic resolution of the constitutional crisis latent in it, then it examines Xunzi's refutation of the three conventional rationalizations of abdication, and it concludes by recapitulating the common Confucian constitutionalist ground that Mencius and Xunzi shared and discussing its implications for the study of constitutional theory.
Liberal Realism: A Liberal Response to the Realist Critique
Authors: Sleat Matt
Published: July 2011

In recent years a powerful body of literature has emerged that challenges contemporary liberal thought on a series of related fronts, which can usefully be described as “realist.” This article focuses on the realist criticism of the dominant liberal account of legitimacy and explores the possibility of developing a political theory that can overcome this challenge while remaining distinctively liberal (hence “liberal realism”). Drawing on the work of a wide range of thinkers who fall outside of the standard Rawlsian tradition in contemporary liberal thinking, the article pursues three different directions in which a theory of liberal realism might be developed—negative, minimal, and partisan—and explores the advantages and shortcomings of each. It attempts to further demonstrate the salience and force of the realist challenge to liberal legitimacy and the need for liberalism to develop an adequate response to it, and offers some proposals concerning the appropriate theoretical framework for doing so.
Modernisation and filial piety among traditional family care-givers: a study of Arab-Israelis in cultural transition
Authors: KHALAILA RABIA , LITWIN HOWARD
Published: July 2011

The purpose of this paper was to examine the association of modernisation and filial piety among adult children care-givers of elderly Arab parents in Israel, and to identify factors that mediate the association. Cross-sectional data were collected in 2006–07 through structured interviews with 250 randomly sampled Arab-Israeli adult children care-givers. Hierarchical regression was then applied to the study variables in the respondents’ scores on a culturally relevant filial piety scale. The results revealed a negative correlation between modernisation, as measured by individualistic lifestyle and level of urbanisation, and filial piety scores. The association between individualistic lifestyle and filial piety was partially mediated by perceived care-giver burden. Given the observed trends, programme and policy planners should establish more services that are uniquely suited to the needs of a changing Arab society, in order to provide culturally relevant long-term support for the family network in a period of accelerated modernisation.
ORDER STATISTICS FROM HETEROGENOUS NEGATIVE BINOMIAL RANDOM VARIABLES
Authors: Xu Maochao , Hu Taizhong
Published: July 2011

In this article, we study the order statistics from heterogenous negative binomial random variables. Sufficient conditions are provided for comparing the extreme order statistics according to the usual stochastic order. For the special case of geometric distribution, a sufficient condition is established for comparing order statistics in the sense of multivariate stochastic order. Applications in the Poisson–Gamma shock model and redundant systems have been described as well.
DETERMINING THE MODE FOR CONVOLUTION POWERS OF DISCRETE UNIFORM DISTRIBUTION
Authors: Belbachir Hacène
Published: July 2011

We specify the smallest mode of the ordinary multinomials leading to the expression of the maximal probability of convolution powers of the discrete uniform distribution. The generating function for an extension of the maximal probability is given.
The Antislavery Judge Reconsidered
Authors: Schmitt Jeffrey M.
Published: July 2011

It is conventionally believed that neutral legal principles required antislavery judges to uphold proslavery legislation in spite of their moral convictions against slavery. Under this view, an antislavery judge who ruled on proslavery legislation was forced to choose, not between liberty and slavery, but rather between liberty and fidelity to his conception of the judicial role in a system of limited government. Focusing on the proslavery Fugitive Slave Act of 1850, this article challenges the conventional view by arguing that the constitutionality of the fugitive act was ambiguous; meaning that neutral legal principles supported a ruling against the fugitive act as well as a ruling in favor of it, and that prominent antislavery judges were influenced to uphold the act by a belief that doing so was necessary in order to preserve the Union.
Quality Assurance Testing for Modern Optical Imaging Systems
Authors: Stack Robert F. , Bayles Carol J. , Girard Anne-Marie , Martin Karen , Opansky Cynthia , Schulz Katherine , Cole Richard W.
Published: July 2011

The days of being able to ascertain instrument performance by simply peering through the eye pieces at a specimen are gone. However, users and granting agencies need to be confident that data collected on these instruments is uniform and quantifiable both over time and between instruments. Ideally, a LASER should not fluctuate, illumination should be completely uniform, and colors should be perfectly aligned. To check the current performance of imaging equipment, we conducted a worldwide research study utilizing three image-based tests: long-/short-term illumination stability, co-registration of signals across various wavelengths, and field illumination uniformity. To differentiate between “acceptable” and “unacceptable” performance, the deviation in illumination power could not exceed 10% (long term) or 3% (short term), the difference in the center-of-mass of imaged multicolored beads could not exceed >1 pixel between different wavelengths, and field illumination values could not exceed 10% (horizontal) or 20% (diagonal) deviation. This study established the current state of microscope performance through simple, efficient, and robust tests, while defining relative standards to assist cores in maintaining their instruments in optimal operating conditions. We developed cross-platform performance standards that will improve the validity of quantitative measurements made using various light microscopes.
The role of enteric glia in gut inflammation
Authors: von Boyen Georg , Steinkamp Martin
Published: July 2011

A neuro-glia interaction is part of gut inflammation and essential for the integrity of the bowel. A loss of enteric glia cells (EGCs) led to a fatal haemorrhagic jejuno-ileitis and death in a few days. Although a diminished EGC network is postulated in inflammatory bowel disease and enteric glia pathology is described in Chagas' disease the role of EGCs in the onset of these disease complexes is not definitely clear. Several lines of evidence implicate that the secretion of different factors by enteric glia may be the key for modulating gut homeostasis. As mucosal integrity might be important for remission in Crohn's disease and inflammation of the enteric nervous system is part of the pathology in Chagas' disease, the role of EGCs during gut inflammation could be part of the key to understand these diseases.
3‐D flow and scour near a submerged wing dike: ADCP measurements on the Missouri River
Authors: Jamieson E. C. , Rennie C. D. , Jacobson R. B. , Townsend R. D.
Published: July 2011

Detailed mapping of bathymetry and three‐dimensional water velocities using a boat‐mounted single‐beam sonar and acoustic Doppler current profiler (ADCP) was carried out in the vicinity of two submerged wing dikes located in the Lower Missouri River near Columbia, Missouri. During high spring flows the wing dikes become submerged, creating a unique combination of vertical flow separation and overtopping (plunging) flow conditions, causing large‐scale three‐dimensional turbulent flow structures to form. On three different days and for a range of discharges, sampling transects at 5 and 20 m spacing were completed, covering the area adjacent to and upstream and downstream from two different wing dikes. The objectives of this research are to evaluate whether an ADCP can identify and measure large‐scale flow features such as recirculating flow and vortex shedding that develop in the vicinity of a submerged wing dike; and whether or not moving‐boat (single‐transect) data are sufficient for resolving complex three‐dimensional flow fields. Results indicate that spatial averaging from multiple nearby single transects may be more representative of an inherently complex (temporally and spatially variable) three‐dimensional flow field than repeated single transects. Results also indicate a correspondence between the location of calculated vortex cores (resolved from the interpolated three‐dimensional flow field) and the nearby scour holes, providing new insight into the connections between vertically oriented coherent structures and local scour, with the unique perspective of flow and morphology in a large river.
Relevance of local compound‐specific transverse dispersion for conservative and reactive mixing in heterogeneous porous media
Authors: Chiogna Gabriele , Cirpka Olaf A. , Grathwohl Peter , Rolle Massimo
Published: July 2011

Different measures of dilution have been proposed to describe solute mixing in heterogeneous porous media. Most of these approaches lead to the definition of effective dispersion coefficients. In order to quantify mixing, these up‐scaled parameters should account for both local‐scale dispersion and effects of flow variability in heterogeneous formations (e.g., flow focusing in high‐conductivity and defocusing in low‐conductivity inclusions). The correct quantification of mixing is particularly important for transport of compounds undergoing reactions. Recent results of multitracer laboratory experiments showed a dependency of local transverse dispersion on molecular diffusion over a wide range of flow velocities, implying compound‐specific transverse mixing even at intermediate and high Péclet numbers. The goal of this study is to assess the relevance of a compound‐specific local‐scale transverse dispersion on conservative and reactive mixing in heterogeneous domains at the field scale. We restrict our analysis to steady state two‐dimensional flow and transport with continuous injection from a line source. We present numerical simulations in heterogeneous domains with different characteristics of variability in the conductivity field, and apply as measures of solute mixing: (1) the effective transverse dispersion coefficient derived from second central spatial moments, (2) a dispersion coefficient derived from flux‐related second central spatial moments, (3) the scalar dissipation rate, and (4) a dispersion coefficient derived from the flux‐related dilution index. The results indicate compound‐specific transverse mixing behavior also at the field scale which is particularly significant in case of low to moderately heterogeneous porous media. Moreover, we show that measures of dilution calculated in a flux‐related framework result in an improved quantification of mixing processes and allow to define up‐scaled parameters (i.e., effective transverse dispersion coefficients) affected by a low degree of uncertainty. For mixing‐controlled reactive transport we illustrate the importance of compound‐dependent local effects on the length of reactive solute plumes.
Ecohydrological consequences of non‐native riparian vegetation in the southwestern United States: A review from an ecophysiological perspective
Authors: Hultine K. R. , Bush S. E.
Published: July 2011

Protecting water resources for expanding human enterprise while conserving valued natural habitat is among the greatest challenges of the 21st century. Global change processes such as climate change and intensive land use pose significant threats to water resources, particularly in arid regions where potential evapotranspiration far exceeds annual rainfall. Potentially compounding these shortages is the progressive expansion of non‐native plant species in riparian areas along streams, canals and rivers in geographically arid regions. This paper sets out to identify when and where non‐native riparian plant species are likely to have the highest potential impact on hydrologic fluxes of arid and semiarid river systems. We develop an ecophysiological framework that focuses on two main criteria: (1) examination of the physiological traits that promote non‐native species establishment and persistence across environmental gradients, and (2) assessment of where and to what extent hydrologic fluxes are potentially altered by the establishment of introduced species at varying scales from individual plants, to small river reaches, to entire river basins. We highlight three non‐native plant species that currently dominate southwestern United States riparian forests. These include tamarisk (Tamarix spp.), Russian olive (Eleagnus angustifolia), and Russian knapweed (Acroptilon repens). As with other recent reviews, we suspect that in many cases the removal of these, and other non‐native species will have little or no impact on either streamflow volume or groundwater levels. However, we identify potential exceptions where the expansion of non‐native plant species could have significant impact on ecohydrologic processes associated with southwestern United States river systems. Future research needs are outlined that will ultimately assist land managers and policy makers with restoration and conservation priorities to preserve water resources and valued riparian habitat given limited economic resources.
Truncation of the Mrp20 protein reveals new ribosome‐assembly subcomplex in mitochondria
Authors: Kaur Jasvinder , Stuart Rosemary A
Published: July 2011

Mitochondrial ribosomal protein 20 (Mrp20) is a component of the yeast mitochondrial large (54S) ribosomal subunit and is homologous to the bacterial L23 protein, located at the ribosomal tunnel exit site. The carboxy‐terminal mitochondrial‐specific domain of Mrp20 was found to have a crucial role in the assembly of the ribosomes. A new, membrane‐bound, ribosomal‐assembly subcomplex composed of known tunnel‐exit‐site proteins, an uncharacterized ribosomal protein, MrpL25, and the mitochondrial peroxiredoxin (Prx), Prx1, accumulates in an mrp20ΔC yeast mutant. Finally, data supporting the idea that the inner mitochondrial membrane acts as a platform for the ribosome assembly process are discussed.
USP22 regulates cell proliferation by deubiquitinating the transcriptional regulator FBP1
Authors: Atanassov Boyko S , Dent Sharon Y R
Published: July 2011

Ubiquitin‐specific protease 22 (USP22) edits the histone code by deubiquitinating H2A and H2B as part of the mammalian SAGA (Spt‐Ada‐Gcn5) complex, and is required for transcriptional regulation and normal cell‐cycle progression. Here, we show that USP22 affects the expression of p21 by altering far upstream element (FUSE)‐binding protein 1 (FBP1) ubiquitination, as ablation of USP22 leads to increased FBP1 ubiquitination and decreased FBP1 protein occupancy at the p21 gene. Surprisingly, increased polyubiquitination of FBP1 does not alter its protein stability, but instead modulates the stable recruitment of FBP1 to target loci. Our results indicate a mechanism by which USP22 regulates cell proliferation and tumorigenesis.
Proteomic insights into the lifestyle of an environmentally relevant marine bacterium
Authors: Christie-Oleza Joseph Alexander , Fernandez Bernard , Nogales Balbina , Bosch Rafael , Armengaud Jean
Published: July 2011

In terms of lifestyle, free-living bacteria are classified as either oligotrophic/specialist or opportunist/generalist. Heterogeneous marine environments such as coastal waters favour the establishment of marine generalist bacteria, which code for a large pool of functions. This is basically foreseen to cope with the heterogeneity of organic matter supplied to these systems. Nevertheless, it is not known what fraction of a generalist proteome is needed for house-keeping functions or what fraction is modified to cope with environmental changes. Here, we used high-throughput proteomics to define the proteome of Ruegeria pomeroyi DSS-3, a model marine generalist bacterium of the Roseobacter clade. We evaluated its genome expression under several natural environmental conditions, revealing the versatility of the bacterium to adapt to anthropogenic influence, poor nutrient concentrations or the presence of the natural microbial community. We also assayed 30 different laboratory incubations to increase proteome coverage and to dig further into the functional genomics of the bacterium. We established its core proteome and the proteome devoted to adaptation to general cellular physiological variations (almost 50%). We suggest that the other half of its theoretical proteome is the opportunist genetic pool devoted exclusively to very specific environmental conditions.
Phylogeny and fitness of Vibrio fischeri from the light organs of Euprymna scolopes in two Oahu, Hawaii populations
Authors: Wollenberg Michael S , Ruby Edward G
Published: July 2011

The evolutionary relationship among Vibrio fischeri isolates obtained from the light organs of Euprymna scolopes collected around Oahu, Hawaii, were examined in this study. Phylogenetic reconstructions based on a concatenation of fragments of four housekeeping loci (recA, mdh, katA, pyrC) identified one monophyletic group (‘Group-A’) of V. fischeri from Oahu. Group-A V. fischeri strains could also be identified by a single DNA fingerprint type. V. fischeri strains with this fingerprint type had been observed to be at a significantly higher abundance than other strains in the light organs of adult squid collected from Maunalua Bay, Oahu, in 2005. We hypothesized that these previous observations might be related to a growth/survival advantage of the Group-A strains in the Maunalua Bay environments. Competition experiments between Group-A strains and non-Group-A strains demonstrated an advantage of the former in colonizing juvenile Maunalua Bay hosts. Growth and survival assays in Maunalua Bay seawater microcosms revealed a reduced fitness of Group-A strains relative to non-Group-A strains. From these results, we hypothesize that there may exist trade-offs between growth in the light organ and in seawater environments for local V. fischeri strains from Oahu. Alternatively, Group-A V. fischeri may represent an example of rapid, evolutionarily significant, specialization of a horizontally transmitted symbiont to a local host population.
Active and total microbial communities in forest soil are largely different and highly stratified during decomposition
Authors: Baldrian Petr , Kolařík Miroslav , Štursová Martina , Kopecký Jan , Valášková Vendula , Větrovský Tomáš , Žifčáková Lucia , Šnajdr Jaroslav , Rídl Jakub , Vlček Čestmír , Voříšková Jana
Published: July 2011

Soils of coniferous forest ecosystems are important for the global carbon cycle, and the identification of active microbial decomposers is essential for understanding organic matter transformation in these ecosystems. By the independent analysis of DNA and RNA, whole communities of bacteria and fungi and its active members were compared in topsoil of a Picea abies forest during a period of organic matter decomposition. Fungi quantitatively dominate the microbial community in the litter horizon, while the organic horizon shows comparable amount of fungal and bacterial biomasses. Active microbial populations obtained by RNA analysis exhibit similar diversity as DNA-derived populations, but significantly differ in the composition of microbial taxa. Several highly active taxa, especially fungal ones, show low abundance or even absence in the DNA pool. Bacteria and especially fungi are often distinctly associated with a particular soil horizon. Fungal communities are less even than bacterial ones and show higher relative abundances of dominant species. While dominant bacterial species are distributed across the studied ecosystem, distribution of dominant fungi is often spatially restricted as they are only recovered at some locations. The sequences of cbhI gene encoding for cellobiohydrolase (exocellulase), an essential enzyme for cellulose decomposition, were compared in soil metagenome and metatranscriptome and assigned to their producers. Litter horizon exhibits higher diversity and higher proportion of expressed sequences than organic horizon. Cellulose decomposition is mediated by highly diverse fungal populations largely distinct between soil horizons. The results indicate that low-abundance species make an important contribution to decomposition processes in soils.
Consumer Estimation of Recommended and Actual Calories at Fast Food Restaurants
Authors: Elbel Brian
Published: July 2011

Recently, localities across the United States have passed laws requiring the mandatory labeling of calories in all chain restaurants, including fast food restaurants. This policy is set to be implemented at the federal level. Early studies have found these policies to be at best minimally effective in altering food choice at a population level. This paper uses receipt and survey data collected from consumers outside fast food restaurants in low‐income communities in New York City (NYC) (which implemented labeling) and a comparison community (which did not) to examine two fundamental assumptions necessary (though not sufficient) for calorie labeling to be effective: that consumers know how many calories they should be eating throughout the course of a day and that currently customers improperly estimate the number of calories in their fast food order. Then, we examine whether mandatory menu labeling influences either of these assumptions. We find that approximately one‐third of consumers properly estimate that the number of calories an adult should consume daily. Few (8% on average) believe adults should be eating over 2,500 calories daily, and approximately one‐third believe adults should eat lesser than 1,500 calories daily. Mandatory labeling in NYC did not change these findings. However, labeling did increase the number of low‐income consumers who correctly estimated (within 100 calories) the number of calories in their fast food meal, from 15% before labeling in NYC increasing to 24% after labeling. Overall knowledge remains low even with labeling. Additional public policies likely need to be considered to influence obesity on a large scale.
Expression of New Loci Associated With Obesity in Diet‐Induced Obese Rats: From Genetics to Physiology
Authors: Gutierrez‐Aguilar Ruth , Kim Dong‐Hoon , Woods Stephen C. , Seeley Randy J.
Published: July 2011

Genome‐wide association studies (GWAS) are a powerful tool for revealing genes associated with common human obesity. New loci associated with obesity have recently been reported, but their function and metabolic implications remain to be elucidated. In order to begin identifying the role of some of these obesity‐related loci, the closest genes to the polymorphism of each locus were selected and their expression was compared in the hypothalamus, adipose tissue, liver, soleus muscle, and extensor digitorum longus muscle (EDL) of Long‐Evans rats maintained on chow or a high‐fat diet (HFD) for 6 weeks. From a total of 19 genes analyzed, seven genes (ETV5, FTO, GNPDA2, KCTD15, TMEM18, MC4R, and SH2B1) were down‐regulated in the hypothalamus of HFD compared to chow‐fed rats. In adipose tissue of rats fed on HFD, the mRNA levels of BCDIN3, KCTD15, and SULT1A1 were down‐regulated, whereas those of MTCH2, PTER, and TUFM were up‐regulated. In the liver, three genes were up‐regulated (PTER, SULT1A1, and TUFM) in HFD relative to chow‐fed rats, and TMEM18 was down‐regulated. Finally, in soleus muscle of HFD‐fed rats, BCDIN3, BDNF, and TMEM18 were down‐regulated, and in the EDL muscle SH2B1 and TUFM were up‐regulated. mRNA levels in the hypothalamus were compared between fed and fasted states, and only KCTD15 was down‐regulated during fasting when fed a chow diet. In conclusion, novel genes found to be associated with obesity are regulated by a HFD and the mRNA levels of KCTD15 is dependent on the nutritional status. These results suggest a potential role of these genes in the regulation of energy balance.
Dephosphorylation of specific sites in the kinase-specificity sequence domain leads to ubiquitin-mediated degradation of the tyrosine phosphatase STEP
Authors: Mukherjee Saibal , Poddar Ranjana , Deb Ishani , Paul Surojit
Published: July 2011

STEP (striatal-enriched phosphatase) is a non-receptor tyrosine phosphatase that is specifically expressed in the neurons of the central nervous system. STEP regulates the activity of several effector molecules involved in synaptic plasticity and neuronal cell survival, including MAPKs (mitogen-activated protein kinases), Src family kinases and NMDA (N-methyl-D-aspartic acid) receptors. The critical role of STEP in regulating these effectors requires that its activity be tightly regulated. Previous studies have demonstrated that the activity of STEP is regulated through reversible phosphorylation of a serine residue within the KIM (kinase-interacting motif), by cAMP-dependent PKA (protein kinase A). In the present paper we show that STEP is endogenously phosphorylated at two additional sites located within the KISs (kinase-specificity sequences). The basal activity of ERK (extracellular-signal-regulated kinase) and p38 MAPKs plays an important role in the phosphorylation of these two sites. Dephosphorylation of these two sites leads to polyubiquitination and proteolytic degradation of STEP. Conversely, the proteasome inhibitors MG-132 and epoxomicin can stabilize STEP. The active form of STEP is more susceptible to degradation than the inactive form. Taken together the results of the present paper establish that ubiquitin-dependent proteolysis could be a novel mechanism for irreversibly terminating the activity of STEP.
Symmetric dimethylarginine is a marker of detrimental outcome in the acute phase after ischaemic stroke: role of renal function
Authors: Lüneburg Nicole , von Holten Rouven-Alexander , Töpper Rudolf F. , Schwedhelm Edzard , Maas Renke , Böger Rainer H.
Published: July 2011

Methylarginines have been shown to interfere with NO (nitric oxide) formation by inhibiting NOS (NO synthase)–ADMA (asymmetric dimethylarginine) and cellular L-arginine uptake into the cell [ADMA and SDMA (symmetric dimethylarginine)]. In a recent study, elevation of SDMA was related to long-term mortality in patients recruited 30 days after a stroke event. In the present study, we aimed at investigating the association of SDMA and adverse clinical outcome in the early phase (first 30 days) after acute ischaemic stroke. A total of 137 patients were recruited immediately upon admission to the emergency unit with an acute ischaemic stroke. Plasma levels of methylarginines were determined by a validated LC–MS/MS (liquid chromatography–tandem MS) method. Patients were prospectively followed for 30 days. A total of 25 patients (18.2%) experienced the primary composite endpoint [death, recurrent stroke, MI (myocardial infarction) and rehospitalization]. SDMA plasma levels were significantly higher in stroke patients compared with patients without event (0.89±0.80 compared with 0.51±0.24 μmol/l; P<0.001). SDMA levels were significantly correlated with markers of renal function. Kaplan–Meier survival analysis demonstrated that cumulative survival decreased significantly with ascending tertiles of SDMA (P<0.001). Our study provides the first data indicating that SDMA is strongly associated with adverse clinical outcome during the first 30 days after ischaemic stroke. Our results strengthen the prognostic value of renal function in patients with stroke and confirm the hypothesis that SDMA is a promising marker for renal function.
Point defects in hexagonal BN, BC3 and BCxN compounds studied by x-ray absorption near-edge structure
Authors: Caretti Ignacio , Jiménez Ignacio
Published: July 2011

The generation of point defects in highly oriented pyrolytic boron nitride (HOPBN) after Ar+ ion bombardment in ultrahigh vacuum and subsequent exposure to air was studied by angle-resolved x-ray absorption near edge structure (XANES). The pristine HOPBN showed well-oriented boron nitride (BN) basal planes parallel to the surface, with a negligible amount of defects. Amorphization of the BN structure took place after Ar+ sputtering, as indicated by the broadening of the XANES spectra and significant decrease of the characteristic π* states. Following air exposure, the XANES analysis revealed a spontaneous reorganization of the sample structure. The appearance of four new B1s π* excitonic peaks indicates an oxygen decoration process of the nitrogen vacancies created by ion bombardment. A core-level shift model is presented to support this statement. This model is successfully extended to the case of oxygen substitutional defects in hexagonal BC3 and BCxN (0 < x < 4) materials, which can be applied to any B-based sp2-bonded honeycomb structure.