bluuebunny/crossref_metadata_2025 huggingface dataset:
Parameterization of topographic effect on surface solar radiation
Authors: Lai Yen‐Jen , Chou Ming‐Dah , Lin Po‐Hsiung
Published: January 2010

Topographic impact on the surface solar (shortwave (SW)) radiation was investigated using a 40 m high‐resolution digital topographic data model and a radiative transfer model. With applications to the complex terrain of Taiwan, we found that the spatial variation of the surface SW radiation has a strong diurnal cycle. The standard deviation of the SW radiation, σf, over Taiwan is nearly constant for a given solar zenith angle (SZA). The maximum σf occurs at SZA ∼55°, corresponding to midmorning (early morning) and midafternoon (late afternoon) in winter (summer). For a spatial resolution of 40 m, the σf over Taiwan attains a maximum value of 300 W m−2, which is ∼50% of the domain mean SW radiation. The topographic impact on the spatial variation of SW radiation increases with decreasing grid box size, Δx. In mesoscale land and atmospheric models, Δx is small, and the topographic impact is strong. Over Taiwan, the standard deviation of the difference between the daily mean SW radiation computed with a spatial resolution of 40 m and that computed with degraded spatial resolution reaches 25 W m−2 for Δx = 1 km and 8 W m−2 for Δx = 10 km, indicating the importance of topographic impact on the surface SW radiation in mesoscale land and atmospheric models. We developed a parameterization of the topographic impact on the surface SW radiation that scales the SW radiation computed for a flat surface without shading by surrounding terrains. The scaling is separately applied to the direct and diffuse radiation. It is applicable to all clear, aerosol‐laden, and cloudy conditions and to all spatial resolutions with Δx > 40 m.
Sampling procedures for throughfall monitoring: A simulation study
Authors: Zimmermann Beate , Zimmermann Alexander , Lark Richard Murray , Elsenbeer Helmut
Published: January 2010

What is the most appropriate sampling scheme to estimate event‐based average throughfall? A satisfactory answer to this seemingly simple question has yet to be found, a failure which we attribute to previous efforts' dependence on empirical studies. Here we try to answer this question by simulating stochastic throughfall fields based on parameters for statistical models of large monitoring data sets. We subsequently sampled these fields with different sampling designs and variable sample supports. We evaluated the performance of a particular sampling scheme with respect to the uncertainty of possible estimated means of throughfall volumes. Even for a relative error limit of 20%, an impractically large number of small, funnel‐type collectors would be required to estimate mean throughfall, particularly for small events. While stratification of the target area is not superior to simple random sampling, cluster random sampling involves the risk of being less efficient. A larger sample support, e.g., the use of trough‐type collectors, considerably reduces the necessary sample sizes and eliminates the sensitivity of the mean to outliers. Since the gain in time associated with the manual handling of troughs versus funnels depends on the local precipitation regime, the employment of automatically recording clusters of long troughs emerges as the most promising sampling scheme. Even so, a relative error of less than 5% appears out of reach for throughfall under heterogeneous canopies. We therefore suspect a considerable uncertainty of input parameters for interception models derived from measured throughfall, in particular, for those requiring data of small throughfall events.
Gene expression patterns of osteocyte‐like MLO‐Y4 cells in response to cyclic compressive force stimulation
Authors: Chen Wenchuan , Qing Hai , He Yun , Wang Jian , Zhu Zhimin , Wang Hang
Published: January 2010

Although osteocytes have long been regarded as mechanosensors for translating mechanical signals into biochemical signals to regulate the other bone cells, the global gene expression patterns and pathways of osteocytes responding to mechanical stimulation are not well defined. We investigated CCF (cyclic compressive force) responsive gene expression patterns at different time‐points using Mouse genome‐wide oligonucleotide microarrays with an osteocyte‐like MLO‐Y4 cell model. We performed a SOM (self‐organizing maps) clustering algorithm based on pattern similarity to organize clusters of temporal expression patterns, and used qRT‐PCR (quantitative reverse transcriptase PCR) analysis to validate expression patterns of selected genes. We also used functional and pathway analysis to evaluate the biological features of the data. In this study, we derived a biological hypothesis from the gene expression profiles that CCF triggers a tightly regulated transcriptional programme to induce bone resorption cell signalling and involves common pathways in osteocytes.
Home Literacy Experiences and Early Childhood Disability: A Descriptive Study Using the National Household Education Surveys (NHES) Program Database
Authors: Breit-Smith Allison , Cabell Sonia Q. , Justice Laura M.
Published: January 2010

Purpose

The present article illustrates how the National Household Education Surveys (NHES; U.S. Department of Education, 2009) database might be used to address questions of relevance to researchers who are concerned with literacy development among young children. Following a general description of the NHES database, a study is provided that examines the extent to which parent-reported home literacy activities and child emergent literacy skills differ for children with (a) developmental disabilities versus those who are developing typically, (b) single disability versus multiple disabilities, and (c) speech-language disability only versus other types of disabilities.

Method

Four hundred and seventy-eight preschool-age children with disabilities and a typically developing matched sample (based on parent report) were identified in the 2005 administration of the Early Childhood Program Participation (ECPP) Survey in the NHES database. Parent responses to survey items were then compared between groups.

Results

After controlling for age and socioeconomic status, no significant differences were found in the frequency of home literacy activities for children with and without disabilities. Parents reported higher levels of emergent literacy skills for typically developing children relative to children with disabilities.

Conclusions

These findings suggest the importance of considering the home literacy experiences and emergent literacy skills of young children with disabilities when making clinical recommendations.
A Review of Developmental and Applied Language Research on African American Children: From a Deficit to Difference Perspective on Dialect Differences
Authors: Stockman Ida J.
Published: January 2010

Purpose

The contemporary practices of delivering speech, language, and hearing services in schools reflect palpable gains in professional sensitivity to linguistic and cultural diversity.

Method

This article reviews the dominant research themes on the oral language of African American preschoolers who contribute to such diversity in the United States. Specifically, it contrasts the historical and current frameworks that have guided studies of (a) such children’s acquisition and use of English and (b) the strategies used to assess and modify their language.

Conclusion

Research initiatives that can expand knowledge about this group are proposed.
Biochemical factors conferring shoot tolerance to oxidative stress in rice grown in low zinc soil
Authors: Frei Michael , Wang Yunxia , Ismail Abdelbagi M. , Wissuwa Matthias
Published: January 2010

Zinc deficiency reduces rice growth and yield, and this is, in part, due to leaf damage caused by reactive oxygen species (ROS). The aim of this study was to identify biochemical mechanisms conferring tolerance to Zn deficiency-induced oxidative stress. A field experiment and three nutrient solution experiments were conducted with the intolerant genotype IR74 and recombinant inbred lines (RILs) derived from a cross between IR74 and the tolerant landrace Jalmagna. After 2 weeks of growth in low Zn soil, stress symptoms developed in leaves of IR74, but not in the tolerant RIL46. Activity of antioxidant enzymes showed clear treatment effects, but did not explain tolerance of RIL46. On the contrary, the intolerant IR74 showed higher activities of superoxide dismutase (SOD), guaiacol peroxidase (POX), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR) under Zn deficiency. This contrasted with a constitutively higher level of total and reduced ascorbic acid (AsA) in RIL46. Three further nutrient solution experiments focussed on enzymes and reducing substrates of the ascorbate–glutathione cycle. The first experiment included the highly sensitive RIL76 in addition to the genotypes used in the field trial, to test whether the patterns of antioxidant response observed in the field were specific to the genotypes used. This genotype had similarly low AsA level as IR74, but did not respond to Zn deficiency with an increase in enzyme activity, leading to even more pronounced leaf symptoms. In a second experiment, co-segregation of AsA concentration and Zn deficiency tolerance was confirmed in five genotypes from the IR74/Jalmagna quantitative trait loci (QTL) mapping population. A third experiment was conducted to determine whether the observed patterns of antioxidant response were specific to Zn deficiency or would also apply to oxidative stress caused by iron deficiency. Although high AsA level apparently conferred tolerance under both types of stress, the enzymatic response to iron deficiency differed from that to Zn deficiency. In particular, APX activity showed a decrease instead of an increase under low iron stress. In conclusion, we suggest that a high AsA level is a promising target for developing rice genotypes with tolerance to oxidative stress.
Ras membrane orientation and nanodomain localization generate isoform diversity
Authors: Abankwa Daniel , Gorfe Alemayehu A. , Inder Kerry , Hancock John F.
Published: January 2010

The structural elements encoding functional diversity among Ras GTPases are poorly defined. The orientation of the G domain of H-ras with respect to the plane of the plasma membrane is recognized by the Ras binding domain of C-Raf, coupling orientation to MAPK activation. We now show that two other proteins, phosphoinositide-3-kinase-α and the structurally unrelated galectin-1, also recognize G-domain orientation. These results rationalize the role of galectin-1 in generating active GTP-H-ras signaling nanoclusters. However, molecular dynamics simulations of K-ras membrane insertion and fluorescence lifetime imaging microscopy (FLIM)-Förster resonance energy transfer (FRET) imaging of the effector interactions of N-Ras, K-Ras, and M-ras suggest that there are two hyperactive, signaling-competent orientations of the Ras G domain. Mutational and functional analyses establish a clear relationship between effector binding and the amphilicities of helix α4 and the C-terminal hypervariable region, thus confirming that these structural elements critically tune the orientation of the Ras G domain. Finally, we show that G-domain orientation and nanoclustering synergize to generate Ras isoform specificity with respect to effector interactions.
BiP-mediated polar nuclei fusion is essential for the regulation of endosperm nuclei proliferation in
Arabidopsis thaliana
Authors: Maruyama Daisuke , Endo Toshiya , Nishikawa Shuh-ichi
Published: January 2010

Nuclear fusion is an essential process in the sexual reproduction of animals and plants. In flowering plants, nuclear fusion occurs three times: once during female gametogenesis, when the two polar nuclei fuse to produce the diploid central cell nucleus, and twice during double fertilization. The yeast Ig binding protein (BiP) is a molecular chaperone Hsp70 in the endoplasmic reticulum that regulates nuclear membrane fusion during mating. Here we report that in
Arabidopsis thaliana
, BiP is involved in the fusion of polar nuclei during female gametophyte development. BiP-deficient mature female gametophytes contain two unfused polar nuclei, in spite of their close contact. This indicates a surprising conservation of BiP function in nuclear fusion between plants and yeasts. We also found that endosperm nuclear division becomes aberrant after fertilization of the BiP-deficient female gametophytes with wild-type pollen. This is experimental evidence for the importance of fusion of the polar nuclei in the proliferation of endosperm nuclei.
Resolvin D1 binds human phagocytes with evidence for proresolving receptors
Authors: Krishnamoorthy Sriram , Recchiuti Antonio , Chiang Nan , Yacoubian Stephanie , Lee Chih-Hao , Yang Rong , Petasis Nicos A. , Serhan Charles N.
Published: January 2010

Endogenous mechanisms that act in the resolution of acute inflammation are essential for host defense and the return to homeostasis. Resolvin D1 (RvD1), biosynthesized during resolution, displays potent and stereoselective anti-inflammatory actions, such as limiting neutrophil infiltration and proresolving actions. Here, we demonstrate that RvD1 actions on human polymorphonuclear leukocytes (PMNs) are pertussis toxin sensitive, decrease actin polymerization, and block LTB
4
-regulated adhesion molecules (β2 integrins). Synthetic [
3
H]-RvD1 was prepared, which revealed specific RvD1 recognition sites on human leukocytes. Screening systems to identify receptors for RvD1 gave two candidates—ALX, a lipoxin A
4
receptor, and GPR32, an orphan—that were confirmed using a β-arrestin-based ligand receptor system. Nuclear receptors including retinoid X receptor-α and peroxisome proliferator-activated receptor-α, -δ, -γ were not activated by either resolvin E1 or RvD1 at bioactive nanomolar concentrations. RvD1 enhanced macrophage phagocytosis of zymosan and apoptotic PMNs, which increased with overexpression of human ALX and GPR32 and decreased with selective knockdown of these G-protein-coupled receptors. Also, ALX and GPR32 surface expression in human monocytes was up-regulated by zymosan and granulocyte-monocyte–colony-stimulating factor. These results indicate that RvD1 specifically interacts with both ALX and GPR32 on phagocytes and suggest that each plays a role in resolving acute inflammation.
ATM is down-regulated by N-Myc–regulated microRNA-421
Authors: Hu Hailiang , Du Liutao , Nagabayashi Gindy , Seeger Robert C. , Gatti Richard A.
Published: January 2010

Ataxia-telangiectasia mutated (ATM) is a high molecular weight protein serine/threonine kinase that plays a central role in the maintenance of genomic integrity by activating cell cycle checkpoints and promoting repair of DNA double-strand breaks. Little is known about the regulatory mechanisms for ATM expression itself. MicroRNAs are naturally existing regulators that modulate gene expression in a sequence-specific manner. Here, we show that a human microRNA, miR-421, suppresses ATM expression by targeting the 3′-untranslated region (3′UTR) of
ATM
transcripts. Ectopic expression of miR-421 resulted in S-phase cell cycle checkpoint changes and an increased sensitivity to ionizing radiation, creating a cellular phenotype similar to that of cells derived from ataxia-telangiectasia (A-T) patients. Blocking the interaction between miR-421 and
ATM
3′UTR with an antisense morpholino oligonucleotide rescued the defective phenotype caused by miR-421 overexpression, indicating that ATM mediates the effect of miR-421 on cell cycle checkpoint and radiosensitivity. Overexpression of the N-Myc transcription factor, an oncogene frequently amplified in neuroblastoma, induced miR-421 expression, which, in turn, down-regulated ATM expression, establishing a linear signaling pathway that may contribute to N-Myc-induced tumorigenesis in neuroblastoma. Taken together, our findings implicate a previously undescribed regulatory mechanism for ATM expression and ATM-dependent DNA damage response and provide several potential targets for treating neuroblastoma and perhaps A-T.
Leaky RyR2 trigger ventricular arrhythmias in Duchenne muscular dystrophy
Authors: Fauconnier Jérémy , Thireau Jérôme , Reiken Steven , Cassan Cécile , Richard Sylvain , Matecki Stefan , Marks Andrew R. , Lacampagne Alain
Published: January 2010

Patients with Duchenne muscular dystrophy (DMD) have a progressive dilated cardiomyopathy associated with fatal cardiac arrhythmias. Electrical and functional abnormalities have been attributed to cardiac fibrosis; however, electrical abnormalities may occur in the absence of overt cardiac histopathology. Here we show that structural and functional remodeling of the cardiac sarcoplasmic reticulum (SR) Ca
2+
release channel/ryanodine receptor (RyR2) occurs in the
mdx
mouse model of DMD. RyR2 from
mdx
hearts were S-nitrosylated and depleted of calstabin2 (FKBP12.6), resulting in “leaky” RyR2 channels and a diastolic SR Ca
2+
leak. Inhibiting the depletion of calstabin2 from the RyR2 complex with the Ca
2+
channel stabilizer S107 (“rycal”) inhibited the SR Ca
2+
leak, inhibited aberrant depolarization in isolated cardiomyocytes, and prevented arrhythmias in vivo. This suggests that diastolic SR Ca
2+
leak via RyR2 due to S-nitrosylation of the channel and calstabin2 depletion from the channel complex likely triggers cardiac arrhythmias. Normalization of the RyR2-mediated diastolic SR Ca
2+
leak prevents fatal sudden cardiac arrhythmias in DMD.
Development of a mouse model for sporadic and metastatic colon tumors and its use in assessing drug treatment
Authors: Hung Kenneth E. , Maricevich Marco A. , Richard Larissa Georgeon , Chen Wei Y. , Richardson Michael P. , Kunin Alexandra , Bronson Roderick T. , Mahmood Umar , Kucherlapati Raju
Published: January 2010

Most genetically engineered mouse (GEM) models for colon cancer are based on tissuewide or germline gene modification, resulting in tumors predominantly of the small intestine. Several of these models involve modification of the adenomatous polyposis coli (
Apc
) gene and are excellent models for familial cancer predisposition syndromes. We have developed a stochastic somatic mutation model for sporadic colon cancer that presents with isolated primary tumors in the distal colon and recapitulates the entire adenoma–carcinoma–metastasis axis seen in human colon cancer. Using this model, we have analyzed tumors that are either solely mutant in the
Apc
gene or in combination with another colon cancer-associated mutant gene, the
Kras
G12D allele. Because of the restricted location in the distal colon, the natural history of the tumors can be analyzed by serial colonoscopy. As the mammalian target of rapamycin (mTOR) pathway is a critical component of the complex signaling network in colon cancer, we used this model to assess the efficacy of mTOR blockade through rapamycin treatment of mice with established tumors. After treatment,
Apc
mutant tumors were more than 80% smaller than control tumors. However, tumors that possessed both
Apc
and
Kras
mutations did not respond to rapamycin treatment. These studies suggest that mTOR inhibitors should be further explored as potential colorectal cancer therapies in patients whose tumors do not have activating mutations in KRAS.
Evidence of an epithelial stem/progenitor cell hierarchy in the adult mouse lung
Authors: McQualter Jonathan L. , Yuen Karen , Williams Brenda , Bertoncello Ivan
Published: January 2010

The role of lung epithelial stem cells in maintenance and repair of the adult lung is ill-defined, and their identity remains contentious because of the lack of definitive markers for their prospective isolation and the absence of clonogenic assays able to measure their stem/progenitor cell potential. In this study, we show that replication of epithelial–mesenchymal interactions in a previously undescribed matrigel-based clonogenic assay enables the identification of lung epithelial stem/progenitor cells by their colony-forming potential in vitro. We describe a population of EpCAM
hi
CD49f
pos
CD104
pos
CD24
low
epithelial cfus that generate colonies comprising airway, alveolar, or mixed lung epithelial cell lineages when cocultured with EpCAM
neg
Sca-1
pos
lung mesenchymal cells. We show that soluble fibroblast growth factor-10 and hepatocyte growth factor partially replace the requirement for mesenchymal support of epithelial colony formation, allowing clonal passaging and demonstration of their capacity for self-renewal. These data support a model in which the adult mouse lung contains a minor population of multipotent epithelial stem/progenitor cells with the capacity for self-renewal and whose descendants give rise to airway and alveolar epithelial cell lineages in vitro.
Cocaine is pharmacologically active in the nonhuman primate fetal brain
Authors: Benveniste Helene , Fowler Joanna S. , Rooney William D. , Scharf Bruce A. , Backus W. Walter , Izrailtyan Igor , Knudsen Gitte M. , Hasselbalch Steen G. , Volkow Nora D.
Published: January 2010

Cocaine use during pregnancy is deleterious to the newborn child, in part via its disruption of placental blood flow. However, the extent to which cocaine can affect the function of the fetal primate brain is still an unresolved question. Here we used PET and MRI and show that in third-trimester pregnant nonhuman primates, cocaine at doses typically used by drug abusers significantly increased brain glucose metabolism to the same extent in the mother as in the fetus (∼100%). Inasmuch as brain glucose metabolism is a sensitive marker of brain function, the current findings provide evidence that cocaine use by a pregnant mother will also affect the function of the fetal brain. We are also unique in showing that cocaine’s effects in brain glucose metabolism differed in pregnant (increased) and nonpregnant (decreased) animals, which suggests that the psychoactive effects of cocaine are influenced by the state of pregnancy. Our findings have clinical implications because they imply that the adverse effects of prenatal cocaine exposure to the newborn child include not only cocaine’s deleterious effects to the placental circulation, but also cocaine’s direct pharmacological effect to the developing fetal brain.
Platform for in situ real-time measurement of protein-induced conformational changes of DNA
Authors: Spuhler Philipp S. , Knežević Jelena , Yalçin Ayça , Bao Qiuye , Pringsheim Erika , Dröge Peter , Rant Ulrich , Ünlü M. Selim
Published: January 2010

A platform for in situ and real-time measurement of protein-induced conformational changes in dsDNA is presented. We combine electrical orientation of surface-bound dsDNA probes with an optical technique to measure the kinetics of DNA conformational changes. The sequence-specific
Escherichia coli
integration host factor is utilized to demonstrate protein-induced bending upon binding of integration host factor to dsDNA probes. The effects of probe surface density on binding/bending kinetics are investigated. The platform can accommodate individual spots of microarrayed dsDNA on individually controlled, lithographically designed electrodes, making it amenable for use as a high throughput assay.
Localized bases of eigensubspaces and operator compression
Authors: E Weinan , Li Tiejun , Lu Jianfeng
Published: January 2010

Given a complex local operator, such as the generator of a Markov chain on a large network, a differential operator, or a large sparse matrix that comes from the discretization of a differential operator, we would like to find its best finite dimensional approximation with a given dimension. The answer to this question is often given simply by the projection of the original operator to its eigensubspace of the given dimension that corresponds to the smallest or largest eigenvalues, depending on the setting. The representation of such subspaces, however, is far from being unique and our interest is to find the most localized bases for these subspaces. The reduced operator using these bases would have sparsity features similar to that of the original operator. We will discuss different ways of obtaining localized bases, and we will give an explicit characterization of the decay rate of these basis functions. We will also discuss efficient numerical algorithms for finding such basis functions and the reduced (or compressed) operator.
MYCN-regulated microRNAs repress estrogen receptor-α (
ESR1
) expression and neuronal differentiation in human neuroblastoma
Authors: Lovén Jakob , Zinin Nikolay , Wahlström Therese , Müller Inga , Brodin Petter , Fredlund Erik , Ribacke Ulf , Pivarcsi Andor , Påhlman Sven , Henriksson Marie
Published: January 2010

MYCN
, a proto-oncogene normally expressed in the migrating neural crest, is in its amplified state a key factor in the genesis of human neuroblastoma (NB). However, the mechanisms underlying MYCN-mediated NB progression are poorly understood. Here, we present a MYCN-induced miRNA signature in human NB involving the activation and transrepression of several miRNA genes from paralogous clusters. Several family members derived from the
miR-17∼92
cluster, including miR-18a and miR-19a, were among the up-regulated miRNAs. Expression analysis of these miRNAs in NB tumors confirmed increased levels in
MYCN
-amplified samples. Specifically, we show that miR-18a and miR-19a target and repress the expression of estrogen receptor-α (
ESR1
), a ligand-inducible transcription factor implicated in neuronal differentiation. Immunohistochemical staining demonstrated ESR1 expression in human fetal sympathetic ganglia, suggesting a role for ESR1 during sympathetic nervous system development. Concordantly, lentiviral restoration of ESR1 in NB cells resulted in growth arrest and neuronal differentiation. Moreover, lentiviral-mediated inhibition of miR-18a in NB cells led to severe growth retardation, outgrowth of varicosity-containing neurites, and induction of neuronal sympathetic differentiation markers. Bioinformatic analyses of microarray data from NB tumors revealed that high
ESR1
expression correlates with increased event-free survival in NB patients and favorable disease outcome. Thus,
MYCN
amplification may disrupt estrogen signaling sensitivity in primitive sympathetic cells through deregulation of
ESR1
, thereby preventing the normal induction of neuroblast differentiation. Collectively, our findings demonstrate the molecular consequences of abnormal miRNA transcription in a MYCN-driven tumor and offer unique insights into the pathology underlying
MYCN
-amplified NB.
Recreation of the terminal events in physiological integrin activation
Authors: Ye Feng , Hu Guiqing , Taylor Dianne , Ratnikov Boris , Bobkov Andrey A. , McLean Mark A. , Sligar Stephen G. , Taylor Kenneth A. , Ginsberg Mark H.
Published: January 2010

Increased affinity of integrins for the extracellular matrix (activation) regulates cell adhesion and migration, extracellular matrix assembly, and mechanotransduction. Major uncertainties concern the sufficiency of talin for activation, whether conformational change without clustering leads to activation, and whether mechanical force is required for molecular extension. Here, we reconstructed physiological integrin activation in vitro and used cellular, biochemical, biophysical, and ultrastructural analyses to show that talin binding is sufficient to activate integrin αIIbβ3. Furthermore, we synthesized nanodiscs, each bearing a single lipid-embedded integrin, and used them to show that talin activates unclustered integrins leading to molecular extension in the absence of force or other membrane proteins. Thus, we provide the first proof that talin binding is sufficient to activate and extend membrane-embedded integrin αIIbβ3, thereby resolving numerous controversies and enabling molecular analysis of reconstructed integrin signaling.
Fine structure in the cluster decay of radium isotopes
Authors: Santhosh K P
Published: January 2010

Half-life times for 14C cluster emission from various radium isotopes are computed taking interacting potential as the sum of Coulomb and proximity potentials. The half-life time values are compared with experimental data and with the values reported by Poenaru et al using the analytical super-asymmetric fission model (ASAFM). The lowest half-life time for 222Ra stresses the role of the doubly magic 208Pb daughter in the exotic decay process. It is found that neutron excess in the parent nucleus slows down the exotic decay process. The high hindrance factor (HF) of the 14C branch to the ground state (9/2+) and the low HF to the first excited state (11/2+) of the 209Pb daughter are in good agreement with the experimental result. The fine structure from 223Ra gives direct evidence of the presence of a spherical component in the deformed parent nucleus.
Effect of Fe3+ substitution on elastic properties of yttrium iron garnet
Authors: Sharma P U , Modi K B
Published: January 2010

The effect of Fe3+ substitution on the elastic properties of yttrium iron garnet (Y3−x
Fe5+x
O12, x=0.0, 0.1, 0.3 and 0.5) was studied by means of x-ray diffraction, scanning electron microscopy and ultrasonic pulse transmission technique at 300 K. Elastic moduli of the specimens were computed and these are corrected to the void-free state by employing different models. Contrary to expectation, the magnitude of elastic constants is found to decrease with increasing Fe3+ substitution. The lowering of elastic stiffness is mainly due to residual stress-induced spontaneous cracking in the material and its development on increasing grain size with Fe3+ substitution in the system. The variation of elastic moduli and the lower value of lattice energy for polycrystalline specimens as compared to its single crystalline counterpart were explained in the light of various structural and microstructural parameters and the grain boundary misorientation effect.
Entanglement and entropy rates in open quantum systems
Authors: Benatti Fabio , Liguori-Schremp Alexandra M , Paluzzano Giacomo
Published: January 2010

We study a recent conjecture about the behavior of the quantum relative entropy compared to the relative entropy of entanglement in open bipartite systems. The conjecture states that, under a dissipative time evolution, the positive rate of change of the relative entropy will always be larger than that of the relative entropy of entanglement. After explicitly solving a 2-qubit master equation of Lindblad type with separable and entangled stationary states, we show that the conjecture can be violated for initial states with an entangled asymptotic state, while it appears to be confirmed when the asymptotic states are separable.
Computation of Weyl groups of 𝐺-varieties
Authors: Losev Ivan
Published: January 2010

Let

G
G

be a connected reductive group. To any irreducible

G
G

-variety one assigns a certain linear group generated by reflections called the Weyl group. Weyl groups play an important role in the study of embeddings of homogeneous spaces. We establish algorithms for computing Weyl groups for homogeneous spaces and affine homogeneous vector bundles. For some special classes of

G
G

-varieties (affine homogeneous vector bundles of maximal rank, affine homogeneous spaces, homogeneous spaces of maximal rank with a discrete group of central automorphisms) we compute Weyl groups more or less explicitly.
Isolation of Bioactive Compounds That Relate to the Anti‐Platelet Activity of Cymbopogon ambiguus
Authors: Grice I. Darren , Rogers Kelly L. , Griffiths Lyn R.
Published: January 2010

Infusions and decoctions of Cymbopogon ambiguus have been used traditionally in Australia for the treatment of headache, chest infections and muscle cramps. The aim of the present study was to screen and identify bioactive compounds from C. ambiguus that could explain this plant’s anti‐headache activity. A dichloromethane extract of C. ambiguus was identified as having activity in adenosine‐diphosphate‐induced human platelet aggregation and serotonin‐release inhibition bioassays. Subsequent fractionation of this extract led to the isolation of four phenylpropenoids, eugenol, elemicin, eugenol methylether and trans‐isoelemicin. While both eugenol and elemicin exhibited dose‐dependent inhibition of ADP‐induced human platelet serotonin release, only eugenol displayed potent inhibitory activity with an IC50 value of 46.6 μM, in comparison to aspirin, with an IC50 value of 46.1 μM. These findings provide evidence to support the therapeutic efficacy of C. ambiguus in the non‐conventional treatment of headache and inflammatory conditions.
Antioxidant Potential ofMomordica Charantiain Ammonium Chloride‐Induced Hyperammonemic Rats
Authors: Thenmozhi A. Justin , Subramanian P.
Published: January 2010

The present study was aimed to investigate the antioxidant potential ofMomordica charantiafruit extract (MCE) in ammonium chloride‐induced (AC) hyperammonemic rats. Experimental hyperammonemia was induced in adult male Wistar rats (180–200 g) by intraperitoneal injections of ammonium chloride (100 mg kg−1body weight) thrice a week. The effect of oral administration (thrice a week for 8 consecutive weeks) of MCE (300 mg kg−1body weight) on blood ammonia, plasma urea, serum liver marker enzymes and oxidative stress biomarkers in normal and experimental animals was analyzed. Hyperammonemic rats showed a significant increase in the activities of thiobarbituric acid reactive substances, hydroperoxides and liver markers (alanine transaminase, aspartate transaminase and alkaline phosphatase), and the levels of glutathione peroxidase, superoxide dismutase, catalase and reduced glutathione were decreased in the liver and brain tissues. Treatment with MCE normalized the above‐mentioned changes in hyperammonemic rats by reversing the oxidant‐antioxidant imbalance during AC‐induced hyperammonemia, and offered protection against hyperammonemia. Our results indicate that MCE exerting the antioxidant potentials and maintaining the cellular integrity of the liver tissue could offer protection against AC‐induced hyperammonemia. However, the exact underlying mechanism is yet to be investigated, and examination of the efficacy of the active constituents of theM. charantiaon hyperammonemia is desirable.
A Valepotriate Fraction of Valeriana glechomifolia Shows Sedative and Anxiolytic Properties and Impairs Recognition But Not Aversive Memory in Mice
Authors: Maurmann Natasha , Reolon Gustavo Kellermann , Rech Sandra Beatriz , Fett-Neto Arthur Germano , Roesler Rafael
Published: January 2010

Plants of the genus Valeriana (Valerianaceae) are used in traditional medicine as a mild sedative, antispasmodic and tranquilizer in many countries. This study was undertaken to explore the neurobehavioral effects of systemic administration of a valepotriate extract fraction of known quantitative composition of Valeriana glechomifolia (endemic of southern Brazil) in mice. Adult animals were treated with a single intraperitoneal injection of valepotriate fraction (VF) in the concentrations of 1, 3 or 10 mg kg-1, or with vehicle in the pre‐training period before each behavioral test. During the exploration of an open field, mice treated with 10 mg kg-1 of VF showed reduced locomotion and exploratory behavior. Although overall habituation sessions for locomotion and exploratory behavior among vehicle control and doses of VF were not affected, comparison between open‐field and habituation sessions within each treatment showed that VF administration at 1 and 10 mg kg-1 impaired habituation. In the elevated plus‐maze test, mice treated with VF (10 mg kg-1) showed a significant increase in the percentage of time spent in the open arms without significant effects in the number of total arm entries. VF at 3 mg kg-1 produced an impairment of novel‐object recognition memory. In contrast, VF did not affect fear‐related memory assessed in an inhibitory avoidance task. The results indicate that VF can have sedative effects and affect behavioral parameters related to recognition memory.
The Level of Democracy during Interregnum Periods: Recoding the polity2 Score
Authors: Plümper Thomas , Neumayer Eric
Published: January 2010

The polity2 variable from the Polity IV project is the most popular measure of a country's political regime. This article contends that the coding rules employed to create a polity2 score during years of so-called interregnum and affected transitions produce a measure of democracy that lacks face validity. Using both single and multiple imputation methods, we construct and evaluate several variables that offer alternative measures to polity2 during such periods. We recommend that scholars using polity2 test whether their results are robust to using our alternatives and using multiple imputation techniques instead. Where robustness cannot be established, scholars need to theoretically justify the choice of either polity2 or one of the alternatives.
Shallow‐lacustrine sand‐rich deltaic depositional cycles and sequence stratigraphy of the Upper Triassic Yanchang Formation, Ordos Basin, China
Authors: Caineng Zou , Xingyang Zhang , Ping Luo , Lan Wang , Zhong Luo , Liuhong Liu
Published: January 2010

Shallow‐lacustrine delta deposits of the Upper Triassic Yanchang Formation form the most important petroleum reservoir sandstone units in the Ordos Basin, China. Recent hydrocarbon exploration and outcrop studies demonstrated that shallow‐lacustrine sand‐rich deltas developed extensively along the gentle flanks and central part of the basin. The vertical succession of facies indicates that the Yanchang Formation records the entire lacustrine life cycle of the Late Triassic Ordos Basin. Four third‐order transgressive–regressive cycles and two larger shallow‐lacustrine deltaic cycles have been recognized. A process‐based depositional model, derived in part from the modern Ganjiang delta in Poyang Lake, China, is used to infer the origins of the sand‐rich lacustrine delta deposits. Slow basin subsidence, abundant sediment supply, autocyclic processes and a hydrologically open (overfilled) lake setting were the four main controls on the development of basin‐wide sand‐rich deltaic sequences. Recognition that inter‐connected delta‐plain sand bodies lying above the lower sequence boundary of the Yanchang Formation act as important migration pathways for oil, gas and other basin fluids, aids in exploration for stratigraphic and diagenetic traps in the delta plain area.
Soil–atmosphere exchange of CH4, CO, N2O and NOx and the effects of land‐use change in the semiarid Mallee system in Southeastern Australia
Authors: GALBALLY IAN , MEYER C.P. (MICK) , WANG YING‐PING , KIRSTINE WAYNE
Published: January 2010

The semiarid and arid zones cover a quarter of the global land area and support one‐fifth of the world's human population. A significant fraction of the global soil–atmosphere exchange for climatically active gases occurs in semiarid and arid zones yet little is known about these exchanges. A study was made of the soil–atmosphere exchange of CH4, CO, N2O and NOx in the semiarid Mallee system, in north‐western Victoria, Australia, at two sites: one pristine mallee and the other cleared for approximately 65 years for farming (currently wheat). The mean (± standard error) rates of CH4 exchange were uptakes of −3.0 ± 0.5 ng(C) m−2 s−1 for the Mallee and −6.0 ± 0.3 ng(C) m−2 s−1 for the Wheat. Converting mallee forest to wheat crop increases CH4 uptake significantly. CH4 emissions were observed in the Mallee in summer and were hypothesized to arise from termite activity. We find no evidence that in situ growing wheat plants emit CH4, contrary to a recent report. The average CO emissions of 10.1 ± 1.8 ng(C) m−2 s−1 in the Mallee and 12.6 ± 2.0 ng(C) m−2 s−1 in the Wheat. The average N2O emissions were 0.5 ± 0.1 ng(N) m−2 s−1 from the pristine Mallee and 1.4 ± 0.3 ng(N) m−2 s−1 from the Wheat. The experimental results show that the processes controlling these exchanges are different to those in temperate systems and are poorly understood.
Geographic variation in growth response of Douglas‐fir to interannual climate variability and projected climate change
Authors: CHEN PEI‐YU , WELSH CEDAR , HAMANN ANDREAS
Published: January 2010

We used 179 tree ring chronologies of Douglas‐fir [Pseudotsuga menziesii(Mirb.) Franco] from the International Tree‐Ring Data Bank to study radial growth response to historical climate variability. For the coastal variety of Douglas‐fir, we found positive correlations of ring width with summer precipitation and temperature of the preceding winter, indicating that growth of coastal populations was limited by summer dryness and that photosynthesis in winter contributed to growth. For the interior variety, low precipitation and high growing season temperatures limited growth. Based on these relationships, we chose a simple heat moisture index (growing season temperature divided by precipitation of the preceding winter and current growing season) to predict growth response for the interior variety. For 105 tree ring chronologies or 81% of the interior samples, we found significant linear correlations with this heat moisture index, and moving correlation functions showed that the response was stable over time (1901–1980). We proceeded to use those relationships to predict regional growth response under 18 climate change scenarios for the 2020s, 2050s, and 2080s with unexpected results: for comparable changes in heat moisture index, the most southern and outlying populations of Douglas‐fir in Mexico showed the least reduction in productivity. Moderate growth reductions were found in the southern United States, and strongly negative response in the central Rocky Mountains. Growth reductions were further more pronounced for high than for low elevation populations. Based on regional differences in the slope of the growth–climate relationship, we propose that southern populations are better adapted to drought conditions and could therefore contain valuable genotypes for reforestation under climate change. The results support the view that climate change may impact species not just at the trailing edges but throughout their range due to genetic adaptation of populations to local environments.
The contribution of deep‐sea macrohabitat heterogeneity to global nematode diversity
Authors: Vanreusel Ann , Fonseca Gustavo , Danovaro Roberto , Da Silva Maria Cristina , Esteves André M. , Ferrero Tim , Gad Gunnar , Galtsova Valentina , Gambi Cristina , Da Fonsêca Genevois Veronica , Ingels Jeroen , Ingole Baban , Lampadariou Nikolaos , Merckx Bea , Miljutin Dmitry , Miljutina Maria , Muthumbi Agnes , Netto Sergio , Portnova Daria , Radziejewska Teresa , Raes Maarten , Tchesunov Alexei , Vanaverbeke Jan , Van Gaever Saskia , Venekey Virág , Bezerra Tania Nara , Flint Hannah , Copley John , Pape Ellen , Zeppilli Daniela , Martinez Pedro Arbizu , Galeron Joelle
Published: January 2010

The great variety of geological and hydrological conditions in the deep sea generates many different habitats. Some are only recently explored, although their true extent and geographical coverage are still not fully established. Both continental margins and mid‐oceanic seafloors are much more complex ecologically, geologically, chemically and hydrodynamically than originally thought. As a result, fundamental patterns of species distribution first observed and explained in the context of relatively monotonous slopes and abyssal plains must now be re‐evaluated in the light of this newly recognized habitat heterogeneity. Based on a global database of nematode genus composition, collected as part of the Census of Marine Life, we show that macrohabitat heterogeneity contributes significantly to total deep‐sea nematode diversity on a global scale. Different deep‐sea settings harbour specific nematode assemblages. Some of them, like coral rubble zones or nodule areas, are very diverse habitats. Factors such as increased substrate complexity in the case of nodules and corals seem to facilitate the co‐existence of a large number of genera with different modes of life, ranging from sediment dwelling to epifaunal. Furthermore, strong biochemical gradients in the case of vents or seeps are responsible for the success of particular genera, which are not prominent in more typical soft sediments. Many nematode deep‐sea genera are cosmopolitan, inhabiting a variety of deep‐sea habitats and oceans, whereas only 21% of all deep‐sea genera recorded are restricted to a single habitat. In addition to habitat heterogeneity, regional differences are important in structuring nematode assemblages. For instance, seeps from different regions yield different genera that thrive on the sulphidic sediments. This study also shows that many areas and habitats remain highly under‐sampled, affecting our ability to understand fully the contribution of habitat heterogeneity versus regional differences to global nematode diversity.
Allelic diversity and geographical pattern at soybean Kunitz trypsin inhibitor single locus in Chinese wild soybean (Glycine soja Sieb. & Zucc.)
Authors: Wang K. J. , Li X. H. , Takahata Y. , Yamashita T.
Published: January 2010

With 6 figures and 2 tables

Soybean Kunitz trypsin inhibitor (SKTI) is extensively studied for its biological function, anti‐nutritional feature, transgenic insect‐resistant breeding and as a genetic marker for tracing the origin and dissemination of soybeans. In this study, SKTI was revealed to exist with a high level of polymorphism at its single locus in the genus Glycine subgenus Soja. We investigated 5612 individual plants of Chinese wild soybean for polymorphic variation and geographical distribution of SKTI in China. As a result, five new variants were detected. These variants were Tibi7, Tih, Tii, Tij and Tik. Together with the known variants at this locus, the sum surprisingly has accounted up to at least eight electrophoretically distinguishable variants at this locus in Chinese wild soybean. This strongly suggests that Chinese wild soybean has high level of polymorphism at SKTI locus, and this protein has high mutability in the phylogenetic history of SKTI. The geographical pattern of the polymorphism indicated that the variability of SKTI abounded in Northeast China and Tib allele existed with high frequency in the southeastern littoral of China.
Comparison of the play of children with attention deficit hyperactivity disorder by subtypes
Authors: Cordier Reinie , Bundy Anita , Hocking Clare , Einfeld Stewart
Published: January 2010

Background:  Studies have found differences in the nature and severity of social problems experienced by children with different subtypes of attention deficit hyperactivity disorder (ADHD). Given that play is often the context for acquiring social skills, there is surprisingly limited research examining whether these differences distinguish the play of children within the groups.

Methods:  Using the Test of Playfulness (ToP), we examined the similarities and differences in play between children (aged 5–11 years) diagnosed with the three
DSM‐IV ADHD subtypes: inattentive (I‐subtype;n = 46), hyperactive‐impulsive (HI‐subtype;n = 28) and combined subtypes (C‐subtype;n = 31).

Results and conclusions:  Bias interaction, an item‐by‐item analysis, revealed that the hierarchy of ToP items was similar for children with the HI‐ and C‐subtypes, but differed for children with the I‐subtype. Specifically, children with the I‐subtype found it more difficult to become intensely engaged in play and to take on playful mischief and clowning; however, they found social play items to be easier. Conversely, whereas mischief and clowning were relatively easier for children with the HI‐ and C‐subtypes, many items reflecting social interaction were more difficult. These findings suggest that interventions can be tailored to these differing presentations. However, further research is needed to confirm the findings.