bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Calabi‐Yau manifolds with small Hodge numbers
Authors: Candelas P. , Davies R. 
Published: March 2010

AbstractIt is known that many Calabi‐Yau manifolds form a connected web. The question of whether all Calabi‐Yau manifolds form a single web depends on the degree of singularity that is permitted for the varieties that connect the distinct families of smooth manifolds. If only conifolds are allowed then, since shrinking two‐spheres and three‐spheres to points cannot affect the fundamental group, manifolds with different fundamental groups will form disconnected webs. We examine these webs for the tip of the distribution of Calabi‐Yau manifolds where the Hodge numbers (h11, h21) are both small. In the tip of the distribution the quotient manifolds play an important role. We generate via conifold transitions from these quotients a number of new manifolds. These include a manifold with χ = ‐6, that is an analogue of the χ = ‐6 manifold found by Yau, and manifolds with an attractive structure that may prove of interest for string phenomenology. We also examine the relation of some of these manifolds to the remarkable Gross‐Popescu manifolds that have Euler number zero.
A three‐generation Calabi‐Yau manifold with small Hodge numbers
Authors: Braun V. , Candelas P. , Davies R. 
Published: March 2010

AbstractWe present a complete intersection Calabi‐Yau manifold Y that has Euler number ‐72 and which admits free actions by two groups of automorphisms of order 12. These are the cyclic group ℤ12 and the non‐Abelian dicyclic group Dic3. The quotient manifolds have χ = ‐6 and Hodge numbers (h11, h21) = (1,4). With the standard embedding of the spin connection in the gauge group, Y gives rise to an E6 gauge theory with 3 chiral generations of particles. The gauge group may be broken further by means of the Hosotani mechanism combined with continuous deformation of the background gauge field. For the non‐Abelian quotient we obtain a model with 3 generations with the gauge group broken to that of the standard model. Moreover there is a limit in which the quotients develop 3 conifold points. These singularities may be resolved simultaneously to give another manifold with (h11, h21) = (2,2) that lies right at the tip of the distribution of Calabi‐Yau manifolds. This strongly suggests that there is a heterotic vacuum for this manifold that derives from the 3 generation model on the quotient of Y. The manifold Y may also be realised as a hypersurface in a toric variety. The symmetry group does not act torically, nevertheless we are able to identify the mirror of the quotient manifold by adapting the construction of Batyrev.
Optical characterization of intersubband transitions in ZnxCd1‐xSe/Znx′Cdy′Mg1‐x′‐y′Se asymmetric coupled quantum well structures by contactless electroreflectance
Authors: Wu Jiun‐De , Huang Chen‐Tai , Huang Ying‐Sheng , Charles William O. , Shen Aidong , Zhang Qiang , Tamargo Maria. C. 
Published: March 2010

AbstractContactless electroreflectance (CER) was used to characterize the possible optical transitions in a ZnxCd1‐xSe/Znx′Cdy′Mg1‐x′‐y′Se asymmetric coupled quantum well (ACQW) structure grown by molecular beam epitaxy for quantum cascade laser (QCL) applications. CER spectrum revealed a wide range of the possible optical transitions in ACQW structure. The ground state transition was assigned by comparing with the photoluminescence emission signal taken from the same structure. A comprehensive analysis of the CER spectrum led to the identification of various interband transitions. The intersubband transitions were estimated and confirmed by FTIR measurements. The results demonstrate the potential of using CER as a complimentary technique for the contactless and nondestructive characterization of the wide band gap II‐VI ACQW structures for QCL applications (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Control of cadmium vapor pressure at growth and annealing of CdZnTe:Cl crystals with variable content of zinc for nuclear detectors
Authors: Terentyev A. I. , Sedov V. E. , Beregulin E. V. , Karpenko V. P. , Tomasov A. A. , Zelenina N. K. , Matveev O. A. 
Published: March 2010

AbstractConductance compensation of Cd1‐xZnxTe:Cl crystals with variable content of Zn (x = 0,0002, 0,005, 0,01 and 0,05) for nuclear detectors both during postgrowth annealing of ingots and at annealing of separate samples at different vapor pressures of Cd was investigated. It is established that to obtain the Cd1‐xZnxTe:Cl crystals (x≥0.05) with the best transport performances, it is necessary to control cadmium vapour pressure as well as zinc vapour pressure of during material growing. On crystals with Zn content x=0.0002; 0.005; 0.01 with annealing of conditions change it was possible to achieve high values of μeτeand μhτh, comparable with these values for CdTe:Cl. For crystals with x=0.05; 0.1 μeτeand μhτh practically did not depend on conditions of postgrowth annealing (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of Zn1–x–yBexMgySe solid solutions with luminescence and photoacoustic methods
Authors: Firszt Franciszek , Zakrzewski Jacek , Strzałkowski Karol , Maliński Mirosław , Łęgowski Stanisław , Męczyńska Hanna , Marasek Agnieszka , Huang Ying‐Sheng , Dumcenco Dumitru 
Published: March 2010

AbstractZn1–x–yBexMgySe mixed crystals were grown from the melt by the high pressure Bridgman method. Photoluminescence and photoluminescence‐excitation spectra were measured and the origin of luminescence in Zn1–x–yBexMgySe was discussed. Photothermal properties were investigated with photoacoustic method. From the spectral dependence of the amplitude and phase of photoacoustic signal as well as from photoluminescence spectra the values of energy gap were determined. The influence of surface preparation on photoacoustics data was investigated and discussed. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spin quenching of transition metals deposited on MgO insulator and CdO semiconductor density functional calculations
Authors: Shalabi A. S. , Aal S. Abdel , Abdel Halim W. S. , Ghonaim M. S. 
Published: March 2010

AbstractWe have analyzed spin quenching of first row transition metals deposited on (001) defect‐free and defect‐containing surfaces of MgO insulator and CdO semiconductor by means of density functional calculations and embedded cluster model. Clusters of moderate sizes were embedded in the simulated Coulomb fields that closely approximate the Madelung fields of the host surfaces, and relaxation of ions that surround the defect sites was taken into account. Spin states of metals deposited on the defect free surfaces were maintained as in the isolated metals except for Ti, V, and Co on MgO, and Ti, V, and Cr on CdO. On the defect containing surfaces, spin states were maintained too except for Fe on MgO, and V and Cr on CdO. The metal‐support interactions stabilize the low spin state of the adsorbed metal with respect to the isolated metal, but the effect was not in general enough to quench the spin. Spin polarization effects tend to preserve the spin states of the adsorbed metals relative to those of the isolated metals. Although charge transfer took place from the adsorbed metal to the insulator surface, it took place the other way round from the semiconductor surface to the adsorbed metal. The encountered variations in magnetic properties were attributed to the smaller band gap of the semiconductor, and the behavior of a single metal atom adsorbed on a particular surface was a result of a competition between Hund's rule for the adsorbed metal and the formation of a chemical bond at the interface. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Electronic structure and chemical bonding in the ground and low‐lying electronic states of Ta2
Authors: Borin Antonio Carlos , Gobbo João Paulo 
Published: March 2010

AbstractThe electronic structure and chemical bonding of the ground and low‐lying Λ − S and Ω states of Ta2 were investigated at the multiconfiguration second‐order perturbation theory (CASSCF//CASPT2) level. The ground state of Ta2 is computed to be a X3Σ state (Re = 2.120 Å, ωe = 323 cm−1, and De = 4.65 eV), with two low‐lying singlet states close to it (a1Σ: Te = 409 cm−1, Re = 2.131 Å, and ωe = 313 cm−1; b1Γg: Te = 1,038 cm−1, Re = 2.127 Å, and ωe = 316 cm−1). These electronic states are derived from the same electronic configuration: |13σ14σ7δ13π〉. The effective bond order of the X3Σ state is 4.52, which indicates that the Ta atoms are bound by a quintuple chemical bond. The a1Σ state interacts strongly with the X3Σ ground state by a second‐order spin‐orbit interaction, giving rise to the (1)0 (ground state) (dominated by the X3Σ Λ − S ground state) and (9)0 (dominated by the a1Σ Λ − S state) Ω states. These results are in line with those reported for the group 5B homonuclear transition metal diatomics. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
The Role of SMAD4 in Human Embryonic Stem Cell Self-Renewal and Stem Cell Fate
Authors: Avery Stuart , Zafarana Gaetano , Gokhale Paul J. , Andrews Peter W. 
Published: March 2010

Abstract
Transforming growth factor (TGF)-β superfamily proteins play a key role in the regulation of human embryonic stem cells (hESCs). Those of the TGFβ/activin/nodal branch seem to support self-renewal and pluripotency, whereas those of the bone morphogenic protein (BMP) branch induce differentiation. In contrast to this generalization, we found that hESC remained undifferentiated after knockdown of SMAD4 with inducible short hairpin RNA interference, although the knockdown inhibited TGFβ signaling and rendered the cells nonresponsive to BMP-induced differentiation. Moreover, the rapid differentiation of hESC after pharmacological inhibition of TGFβ/activin/nodal receptor signaling was restricted after SMAD4 knockdown. These results suggest that TGFβ/activin/nodal signaling supports the undifferentiated phenotype of hESC by suppressing BMP activity. During long-term culture, SMAD4 knockdown cell populations became less stable and more permissive to neural induction, a situation that was rescued by re-establishment of SMAD4 expression. These results suggest that SMAD4 is not required for maintenance of the undifferentiated state of hESC, but rather to stabilize that state.
May captive populations of Greater Rhea (Rhea americana) act as genetic reservoirs in Argentina?
Authors: Alonso Roldán V. , Navarro J. L. , Gardenal C. N. , Martella M. B. 
Published: March 2010

AbstractThe Greater Rhea (Rhea americana) is a characteristic bird of the Argentine Pampas. Despite the increasing farming interest of this ratite, their natural populations are progressively decreasing in size and range. The object of this study was to evaluate the status of captive populations as potential genetic reservoirs. Using Inter‐Simple Sequence Repeats as molecular markers, levels of genetic variability of F1 individuals from two captive populations were estimated and compared with those of wild populations in the same region. The captive populations were polymorphic for 12.22 and 13.33% of the loci, with a genetic diversity of 0.050. Differences with wild populations were not significant (z=1.79; P>0.05). Therefore, captive populations of rheas in Argentina should not be overlooked as genetic reservoir and source of individuals for reinforcement of natural populations, through reintroduction and translocation. Zoo Biol 30:65–70, 2011. © 2010 Wiley‐Liss, Inc.
Nutritional composition of the diets of South Asian, black African-Caribbean and white European children in the United Kingdom: The Child Heart and Health Study in England (CHASE)
Authors: Donin A. S. , Nightingale C. M. , Owen C. G. , Rudnicka A. R. , McNamara M. C. , Prynne C. J. , Stephen A. M. , Cook D. G. , Whincup P. H. 
Published: March 2010

In the UK, South Asian adults have increased risks of CHD, type 2 diabetes and central obesity. Black African-Caribbeans, in contrast, have increased risks of type 2 diabetes and general obesity but lower CHD risk. There is growing evidence that these risk differences emerge in early life and that nutritional factors may be important. We have therefore examined the variations in nutritional composition of the diets of South Asian, black African-Caribbean and white European children, using 24 h recalls of dietary intake collected during a cross-sectional survey of cardiovascular health in eighty-five primary schools in London, Birmingham and Leicester. In all, 2209 children aged 9–10 years took part, including 558 of South Asian, 560 of black African-Caribbean and 543 of white European ethnicity. Compared with white Europeans, South Asian children reported higher mean total energy intake; their intakes of total fat, polyunsaturated fat and protein (both absolute and as proportions of total energy intake) were higher and their intakes of carbohydrate as a proportion of energy (particularly sugars), vitamin C and D, Ca and haem Fe were lower. These differences were especially marked for Bangladeshi children. Black African-Caribbean children had lower intakes of total and saturated fat (both absolute and as proportions of energy intake), NSP, vitamin D and Ca. The lower total and saturated fat intakes were particularly marked among black African children. Appreciable ethnic differences exist in the nutritional composition of children's diets, which may contribute to future differences in chronic disease risk.
Recurrent neck abscess due to a bronchogenic cyst in an adult
Authors: Hazenberg A J C , Pullmann L M , Henke R-P , Hoppe F 
Published: March 2010

AbstractBackground:Neck abscesses can originate from congenital cervical cysts. Cervical cysts of bronchogenic origin are rare and often asymptomatic. Common symptoms of bronchogenic cysts are stridor, dyspnoea and dysphagia. The reported patient represents the second published case of a bronchogenic cyst causing a neck abscess in an adult.Case report:We report a case of a cervical bronchogenic cyst presenting as a recurrent supraclavicular abscess in a middle-aged woman. During extirpation, a fistula was demonstrated to the right upper lobe of the lung, suspected because the cyst inflated synchronously with respiration.Discussion:The symptoms of bronchogenic cysts are due to the effects of compression or fistulas. In the majority of these cysts, a thorough investigation involving history, examination and radiological imaging does not clearly demonstrate a fistula. Therefore, extirpation is both diagnostic and therapeutic.Conclusion:A bronchogenic cyst is a very rare cause of a recurrent deep neck abscess. Total extirpation is the treatment of choice.
Emotion-modulated startle in anxiety disorders is blunted by co-morbid depressive episodes
Authors: Taylor-Clift A. , Morris B. H. , Rottenberg J. , Kovacs M. 
Published: March 2010

BackgroundWhile anxiety has been associated with exaggerated emotional reactivity, depression has been associated with blunted, or context insensitive, emotional responding. Although anxiety and depressive disorders are frequently co-morbid, surprisingly little is known about emotional reactivity when the two disorders co-occur.MethodWe utilized the emotion-modulated startle (EMS) paradigm to examine the effects of a concurrent depressive episode on emotional reactivity in young adults with anxiety disorders. Using an archival dataset from a multi-disciplinary project on risk factors in childhood-onset depression, we examined eye-blink startle reactions to late-onset auditory startle probes while participants viewed pictures with affectively pleasant, unpleasant and neutral content. EMS response patterns were analyzed in 33 individuals with a current anxiety (but no depressive) disorder, 24 individuals with a current anxiety disorder and co-morbid depressive episode and 96 healthy controls.ResultsControl participants and those with a current anxiety disorder (but no depression) displayed normative linearity in startle responses, including potentiation by unpleasant pictures. By contrast, individuals with concurrent anxiety and depression displayed blunted EMS.ConclusionsAn anxiety disorder concurrent with a depressive episode is associated with reactivity that more closely resembles the pattern of emotional responding that is typical of depression (i.e. context insensitive) rather than the pattern that is typical for anxiety (i.e. exaggerated).
Parity criterion for unstabilized Heegaard splittings
Authors: LEE JUNG HOON 
Published: March 2010

AbstractWe give a parity condition of a Heegaard diagram implying that it is unstabilized. As applications, we show that Heegaard splittings of 2-fold branched coverings of n-component, n-bridge links in S3 are unstabilized, and we also construct unstabilized Heegaard splittings by Dehn twists on any given Heegaard splitting.
Redistributive Nature of the Chinese Social Benefit System: Progressive or Regressive?
Authors: Gao Qin 
Published: March 2010

AbstractUsing nationally representative household survey data and a revealing statistical method, this article investigates the redistributive nature of the Chinese social benefit system within urban and rural areas respectively and in the national context. Like many other dimensions of Chinese society, the redistributive nature of social benefits appeared to be a two-sided story: urban social benefits were much more generous and predominantly progressive, while rural social benefits were minimal and consistently regressive. The national social benefit system was redistributed regressively, but the extent of its regressivity decreased over time, suggesting an equity-oriented policy direction echoed by several recent government initiatives to support rural residents, migrants and the urban poor. The outcomes of these initiatives, especially their redistributive effects, require close observation and await evaluation.
On the Edge between “the People” and “the Population”: Ethnographic Research on the Minimum Livelihood Guarantee
Authors: Cho Mun Young 
Published: March 2010

AbstractThis article examines how local resistance against government attempts to reduce poverty to a technical problem ironically reinforces the precarious state of the poor. It looks at the workings of the minimum livelihood guarantee (dibao) through mundane interactions between street-level officials and poor residents in a workers' village on the periphery of Harbin. As the party-state's primary policy for urban poverty,dibaohas introduced a new rationality that poverty is calculable and flexible. Urban laid-off workers have resisted this by invoking the socialist claim that they are “the people.” I examine how this resistance has led street-level officials to be preoccupied with the old socialist norm of “an ability to work” rather than with “income” asdibao's official criterion. The new local criterion has produced the ironic effect that urban laid-off workers, who were understood to bedibao's main target, have been mostly excluded from the scheme.
What is New in the “New Rural Co-operative Medical System”? An Assessment in One Kazak County of the Xinjiang Uyghur Autonomous Region
Authors: Klotzbücher Sascha , Lässig Peter , Jiangmei Qin , Weigelin-Schwiedrzik Susanne 
Published: March 2010

AbstractIn 2002, the Chinese leadership announced a change in national welfare policy: Voluntary medical schemes at county level, called the “New Rural Co-operative Medical System” should cover all counties by 2010. This article addresses the main characteristics of this system, analyses the introduction of local schemes based on our own field studies in one Kazak county of the Xinjiang Uyghur Autonomous Region since 2006, and argues that the fast progressing of the local scheme and the flexibility shown by local administrators in considering structural and procedural adjustments are not the result of central directives but of local initiatives. Recentralization from the township governments to functional departments in the provincial and the central state administration is only one aspect of current rural governance. Complementary forms of locally embedded responsiveness to the needs of health care recipients are crucial in restructuring the administration and discharge of health care. These new modes of governance are different from the hierarchical control and institutionalized representation of interests of the local population.
Dynamic Statism and Memory Politics: A Case Analysis of the Chinese War Reparations Movement
Authors: Xu Bin , Pu Xiaoyu 
Published: March 2010

AbstractThis study addresses the Chinese Second World War victims' reparations movement (CWRM) against Japan as a case of contemporary Chinese memory politics. While many studies indicate the Chinese government's use of the war memories for political purposes, ours focuses on how official discourses are translated into citizens' political participation and how the state–society interactions lead to variation in the development of the movement sectors within the case of CWRM. Drawing on textual and ethnographic data and a theoretical “dynamic statism,” we argue that the central government's ambivalent attitude towards this ideologically useful yet institutionally troublesome movement created room for local governments and the movement to pursue their own causes. Yet the local and central governments' strong interventions, either facilitation or repression, discouraged civil society's participation and led to the underdevelopment of some movement sectors. In the sectors where the local governments held an attitude of absenteeism or co-operation, the movement was able to mobilize resources from civil society and state institutions and finally developed well.
Global classical solutions of the Boltzmann equation with long-range interactions
Authors: Gressman Philip T. , Strain Robert M. 
Published: March 2010

This is a brief announcement of our recent proof of global existence and rapid decay to equilibrium of classical solutions to the Boltzmann equation without any angular cutoff, that is, for long-range interactions. We consider perturbations of the Maxwellian equilibrium states and include the physical cross-sections arising from an inverse-power intermolecular potential
r

-(
p
-1)

with
p
> 2, and more generally. We present here a mathematical framework for unique global in time solutions for all of these potentials. We consider it remarkable that this equation, derived by Boltzmann (
1
) in 1872 and Maxwell (
2
) in 1867, grants a basic example where a range of geometric fractional derivatives occur in a physical model of the natural world. Our methods provide a new understanding of the effects due to grazing collisions.