bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantum rotor description of the bosonic superfluid–Mott insulator transition in optical lattices
Authors: Polak T. P. , Kopéc T. K. 
Published: April 2009

AbstractThe physics of the Bose–Hubbard (BH) model is the subject of intensive studies in recent years, since it has been realized that BH Hamiltonian can be applied to systems of cold atoms confined in periodic optical lattice potential, where the effects on interactions are strongly enhanced. Our aim is to extend the widely used mean‐field treatment of the superfluid–Mott insulator (SF–MI) transition in the BH model. Our method also improves the strong‐coupling expansion that works well only for sufficiently large insulating gap. The key point of the approach is to consider the representation of strongly interacting bosons as particles with attached U(1) gauge group flux tubes, which constitutes the quantum rotor description. The effective action formalism allows us to cast the problem in terms of the phaseonly action and obtain an analytical formulas for critical lines. Finally, we calculate the zero‐temperature SF–MI phase diagrams for three‐dimensional BH model and compare our results with the outcome of numerical Monte Carlo simulations. We found a very good agreement for the quantitative results regarding the details of the lobe in the phase diagrams showing the quantum transition from superfluid to the Mott insulating phase (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Entanglement of flux qubits through a joint detection of photons
Authors: Kurpas Marcin , Zipper Elżbieta 
Published: April 2009

AbstractWe study the entanglement creation between two flux qubits interacting with electromagnetic field modes. No direct interaction between the qubits exists. Entanglement is reached using the entanglement swapping method by an interference measurement performed on photons. We discuss the influence of off‐resonance and multi‐photon initial states on the qubit–qubit entanglement. The presented scheme is able to drive an initially separable state of two qubits into an highly entangled state suitable for quantum information processing (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multielectron irreducible representations of the magnetic translation group
Authors: Wal Andrzej 
Published: April 2009

AbstractThe symmetry of a 2D Bloch electron in the magnetic field is described by the magnetic translation groups (MTG). Their irreducible representations (IR), parameterized by numbers k1, k2 and s = 1, classify the states of an electron. This classification is performed by using the symmetry adapted bases, i.e. the bases of irreducible representations generated with the help of projection operator technique.The multielectron system will be described by appropriate tensor products of these “one electron” IRs. From the other hand the same description should be obtained by consideration of irreducible representations of MTG with the parameter s identified as the number of electrons in the Landau level. These methods of classification of states are discussed for finite dimensional planar rectangular lattices (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On quantum entanglement and quantum communication
Authors: Żukowski Marek 
Published: April 2009

AbstractThis article presents a talk given at 23rd International Conference on Theoretical Physics (Ustroń, 2008). A new version of Bell's theorem is presented, with inequalities based on four assumptions: realism, locality and “free will” and “principle of rotational symmetry of physical laws”. The new Bell‐type inequalities are derived using a simple geometrical intuition. The assumptions behind Bell's theorem are discussed. A critique of overinterpretations of violations of Bell inequalities is given. Further on, a new criterion for entanglement is presented, based on simple geometrical ideas. This leads to a new class of entanglement identifiers, which is richer than entanglement witnesses. Finally a link between Bell's theorem and communication complexity problems will be shown. It covers also realizations, which do not involve entanglement (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum entanglement of space domains occupied by interacting electrons
Authors: Ramsak A. , Mravlje J. , Rejec T. 
Published: April 2009

AbstractSpin‐entanglement of two electrons occupying two spatial regions – domains – is expressed in a compact form in terms of spin‐spin correlation functions. The power of the formalism is demonstrated on several examples ranging fromgeneration of entanglement by scattering of two electrons to the entanglement of a pair of qubits represented by a double quantum dot coupled to leads. In the latter case the collapse of entanglement due to the Kondo effect is analyzed (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generating experimental designs involving control and noise variables using genetic algorithms
Authors: Rodriguez Myrta , Montgomery Douglas C. , Borror Connie M. 
Published: April 2009

AbstractEfficient estimation of response variables in a process is an important problem that requires experimental designs appropriated for each specific situation. When we have a system involving control and noise variables, we are often interested in the simultaneous optimization of the prediction variance of the mean (PVM) and the prediction variance of the slope (PVS). The goal of this simultaneous optimization is to construct designs that will result in the efficient estimation of important parameters. We construct new computer‐generated designs using a desirability function by transforming PVM and PVS into one desirability value that can be optimized using a genetic algorithm. Fraction of design space (FDS) plots are used to evaluate the new designs and six cases are discussed to illustrate the procedure. Copyright © 2009 John Wiley & Sons, Ltd.
HyBAR: hybrid bone‐attached robot for joint arthroplasty
Authors: Song S. , Mor A. , Jaramaz B. 
Published: April 2009

AbstractBackgroundA number of small bone‐attached surgical robots have been introduced to overcome some disadvantages of large stand‐alone surgical robots. In orthopaedics, increasing demand on minimally invasive joint replacement surgery has also been encouraging small surgical robot developments. Among various technical aspects of such an approach, optimal miniaturization that maintains structural strength for high speed bone removal was investigated.MethodsBy observing advantages and disadvantages from serial and parallel robot structures, a new hybrid kinematic configuration was designed for a bone‐attached robot to perform precision bone removal for cutting the femoral implant cavity during patellofemoral joint arthroplasty surgery. A series of experimental tests were conducted in order to evaluate the performance of the new robot, especially with respect to accuracy of bone preparation.ResultsA miniaturized and rigidly‐structured robot prototype was developed for minimally invasive bone‐attached robotic surgery. A new minimally invasive modular clamping system was also introduced to enhance the robotic procedure. Foam and pig bone experimental results demonstrated a successful implementation of the new robot that eliminated a number of major design problems of a previous prototype.ConclusionsFor small bone‐attached surgical robots that utilize high speed orthopaedic tools, structural rigidity and clamping mechanism are major design issues. The new kinematic configuration using hinged prismatic joints enabled an effective miniaturization with good structural rigidity. Although minor problems still exist at the prototype stage, the new development would be a significant step towards the practical use of such a robot. Copyright © 2009 John Wiley & Sons, Ltd.
MicroRNA 92b Controls the G1/S Checkpoint Gene p57 in Human Embryonic Stem Cells
Authors: Sengupta Srikumar , Nie Jeff , Wagner Ryan J. , Yang Chuhu , Stewart Ron , Thomson James A. 
Published: April 2009

Abstract
Human embryonic stem (ES) cells exhibit a shorter G1 cell cycle phase than most somatic cells. Here, we examine the role of an abundant, human ES cell-enriched microRNA, miR-92b, in cell cycle distribution. Inhibition of miR-92b in human ES cells results in a greater number of cells in the G1 phase and a lower number in the S phase. Conversely, overexpression of miR-92b in differentiated cells results in a decreased number of cells in G1 phase and an increased number in S-phase. p57, a gene whose product inhibits G1 to S-phase progression, is one of the predicted targets of miR-92b. Inhibition of miR-92b in human ES cells increases p57 protein levels, and miR-92b overexpression in differentiated cells decreases p57 protein levels. Furthermore, miR-92b inhibits a luciferase reporter construct that includes part of the 3′ untranslated region of the p57 gene containing the predicted target of the miR-92b seed sequence. Thus, we show that the miRNA miR-92b directly downregulates protein levels of the G1/S checkpoint gene p57.
Disclosure of potential conflicts of interest is found at the end of this article.
Upregulation of RAGE at the blood‐brain barrier in streptozotocin‐induced diabetic mice
Authors: Liu Li Ping , Hong Hao , Liao Jian Ming , Wang Tong Sheng , Wu Jing , Chen Si Si , Li Yong Qi , Long Yan , Xia Yuan Zheng 
Published: April 2009

AbstractDeposition of amyloid‐β peptide (Aβ) in the brain of diabetes is poorly understood. The receptor for advanced glycation end products (RAGE) at the blood‐brain barrier (BBB) is critical for regulation of Aβ homeostasis in the brain. In this studies, we used streptozotocin‐induced diabetic mice to observe the expression of RAGE at the BBB by Western blot and immunocytochemical analysis, and the in vivo blood‐to‐brain influx transport of 125I‐Aβ1–40 using the permeability surface area product (PS) and brain capillary uptake. In the diabetic mice with hyperglycemia (>16.0 mmol/L) at 6 weeks, RAGE expression at the BBB was significantly upregulated, no significant changes of RAGE levels were found at 1 and 3 weeks after diabetes induction. The data of PS and brain capillary uptake for Aβ showed significant RAGE‐dependent transport of Aβ across the BBB and substantial RAGE‐dependent brain capillary uptake at 6 weeks after diabetes induction. We conclude that the upregulation of RAGE at the BBB contributes to cerebral Aβ deposition in the diabetes. Synapse 63:636–642, 2009. © 2009 Wiley‐Liss, Inc.
Phenotypic characterization of mice heterozygous for a null mutation of glutamate carboxypeptidase II
Authors: Han Liqun , Picker Jonathan D. , Schaevitz Laura R. , Tsai Guochuan , Feng Jiamin , Jiang Zhichun , Chu Hillary C. , Basu Alo C. , Berger‐Sweeney Joanne , Coyle Joseph T. 
Published: April 2009

AbstractGlutamate is the major excitatory neurotransmitter in the mammalian central nervous system. Disturbed glutamate signaling resulting in hypofunction of N‐methyl‐D‐aspartate receptors (NMDAR) has been implicated in the pathophysiology of schizophrenia. Glutamate Carboxypeptidase II (GCP II) hydrolyzes N‐acetyl‐alpha L‐aspartyl‐L‐glutamate (NAAG) into glutamate and N‐acetyl‐aspartate. NAAG is a neuropeptide that is an NMDAR antagonist as well as an agonist for the metabotropic glutamate receptor‐3 (mGluR3), which inhibits glutamate release. The aggregate effect of NAAG is thus to attenuate NMDAR activation. To manipulate the expression of GCP II, LoxP sites were inserted flanking exons 1 and 2, which were excised by crossing with a Cre‐expressing mouse. The mice heterozygous for this deletion showed a 50% reduction in the expression level of protein and functional activity of GCP II in brain samples. Heterozygous mutant crosses did not yield any homozygous null animals at birth or as embryos (N > 200 live births and fetuses). These data are consistent with the previous report that GCP II homozygous mutant mice generated by removing exons 9 and 10 of GCP II gene were embryonically lethal and confirm our hypothesis that GCP II plays an essential role early in embryonic development. Heterozygous mice, however, developed normally to adulthood and exhibited increased locomotor activity, reduced social interaction, and a subtle cognitive deficit in working memory. Synapse 63:625–635, 2009. © 2009 Wiley‐Liss, Inc.
Sex Differences in the Effects of Neighborhood Socioeconomic Disadvantage and Social Organization on Rural Adolescents' Aggression Trajectories
Authors: Karriker-Jaffe Katherine J. , Foshee Vangie A. , Ennett Susan T. , Suchindran Chirayath 
Published: April 2009

AbstractWe determined whether effects of neighborhood socioeconomic disadvantage on trajectories of aggression were moderated or mediated by neighborhood social organization and examined sex differences in neighborhood effects for rural adolescents. We used five waves of survey data collected over 2.5 years linked with neighborhood data from interviews with parents and the US Census. The sample (N= 5,118) was 50.1% female, 52.0% white and 38.3% African–American; average age at baseline was 13.1 years. Multilevel growth curve models for both girls and boys showed no significant interactions between neighborhood socioeconomic disadvantage and indicators of social organization. Neither sample showed evidence of mediated effects. In main effects models, neighborhood disadvantage was associated with the average aggression trajectory for girls. For boys, the effects of neighborhood socioeconomic disadvantage and social disorganization appeared to be confounded with each other. Neighborhood disadvantage is detrimental for rural girls regardless of the level of social organization.
Geometrical method to determine the reciprocal screws and applications to parallel manipulators
Authors: Zhao Jianguo , Li Bing , Yang Xiaojun , Yu Hongjian 
Published: April 2009

SUMMARYScrew theory has demonstrated its wide applications in robot kinematics and statics. We aim to propose an intuitive geometrical approach to obtain the reciprocal screws for a given screw system. Compared with the traditional Plücker coordinate method, the new approach is free from algebraic manipulation and can be used to obtain the reciprocal screws just by inspecting the structure of manipulator. The approach is based on three observations that describe the geometrical relation for zero pitch screw and infinite pitch screw. Based on the observations, the reciprocal screw systems of several common kinematic elements are analyzed, including usual kinematic pairs and chains. We also demonstrate usefulness of the geometrical approach by a variety of applications in mobility analysis, Jacobian formulation, and singularity analysis for parallel manipulator. This new approach can facilitate the parallel manipulator design process and provide sufficient insights for existing manipulators.
Was/werevariation: A perspective from London
Authors: Cheshire Jenny , Fox Sue 
Published: April 2009

AbstractThis article presents a systematic analysis of morphosyntactic variation in London English, investigatingwas/werevariation in the speech of adolescents and elderly speakers in a multicultural inner London area and a less diverse outer London area. In outer London, dialect leveling to a mixedwas/weren'tsystem is well underway, as in many other areas of the U.K. Negativeweren'tis frequent and a grammaticalized invariantweren't ittag is developing. In inner London, variation in adolescent speech is strongly influenced by ethnicity, resulting in a lower overall frequency ofwasleveling and, in negative contexts, a mixed pattern of leveling to bothwasn'tandweren't. The patterns of variation of Anglo “heritage” inner London adolescents differ both from elderly speakers in the same area and from their peers in outer London. Our analysis confirms the need for socially realistic models of language change that take account of the social diversity of large multicultural urban cities.
The varying influence of social and linguistic factors on language stability and change: The case of Eskilstuna
Authors: Sundgren Eva 
Published: April 2009

AbstractContinuity and Change in Present-Day Swedish: Eskilstuna Revisited is a large-scale study of language change in real time. In this article, the focus is on the results of a trend study and the analysis of how extralinguistic and linguistic factors influence how language varies and changes.The empirical material consists of informal conversationlike interviews, in which seven morphological and morphophonological variables have been analyzed in terms of the traditional extralinguistic factors of social group, gender, and age, as well as in terms of social networks. These morpho(phono)logical variables are sociolinguistically marked and have been hypothesized to show a process of more or less rapid change from regional dialect toward spoken standard. The rate of change at the level of the community has been slow, however. Comparisons between the influence of extralinguistic and linguistic factors indicate that social forces are more influential than linguistic ones.
The Postcolonial Paradox: Becoming Less than Whole(s) Producing Parts that Exclude Other Parts
Authors: Duggan Joseph F. 
Published: April 2009

AbstractThe purpose of this article is to address coexistent Anglican faith identities that have flourished in contexts after the colonial period. Thus far these identities have been treated as differences in viewpoints. Metaphysically speaking member differences are included as ‘parts’ of the one ‘whole’ Body of Christ. Without a postcolonial metaphysical and theological critique that decolonizes the Body of Christ, as the Church, then parts repeatedly seek, to redefine, restore or reform the ‘whole’ to maintain the whole’s coherence and empowering the former part. Ignoring the metaphysical aspect of ecclesial identity postpones the emergence of a postcolonial Anglican Communion where multiple faith identities can coexist.
Pseudohypha budding patterns of Candida albicans
Authors: Veses Verónica , Gow Neil A.R. 
Published: April 2009

Abstract
Pseudohyphal growth of Candida albicans has been recognized as a morphological growth form that exhibits characteristics that are distinct from those of the budding yeast phase and true hyphal form of this pathogenic fungus. In Saccharomyces cerevisiae, pseudohypha growth involves synchronous unipolar cell divisions that are a modification of the bipolar budding pattern of diploid cells. While pseudohyphae of C. albicans also exhibit unipolar cell divisions, live cell imaging demonstrated departures from the normal unipolar pattern. Buds occasionally followed a bipolar or axial budding event in which buds could be formed from the proximal or distal ends of a parent pseudohypha. This extends the known morphological repertoire of cell division patterns in C. albicans pseudohyphal cells.
Are There Differences in Hospital Cost Between Patients With Nosocomial Methicillin-ResistantStaphylococcus aureusBloodstream Infection and Those With Methicillin-SusceptibleS. aureusBloodstream Infection?
Authors: Ben-David Debby , Novikov Ilya , Mermel Leonard A. 
Published: April 2009

Objective.To examine the impact of methicillin resistance on in-hospital mortality, length of stay, and hospital cost after the onset of nosocomialStaphylococcus aureusbloodstream infection (BSI).Design.A retrospective cohort study.Setting.A tertiary care hospital in Rhode Island.Patients.A cohort of 182 consecutive patients who developed nosocomial BSI due to methicillin-susceptible and methicillin-resistantS. aureus(MSSA and MRSA, respectively)Results.Patients with MRSA BSI had a significantly longer total length of hospital and intensive care unit (ICU) stay before the onset of BSI and a higher average daily cost. Compared with ICU patients with MSSA BSI, those with MRSA BSI had a higher median total hospital cost ($42,137 vs $113,852), higher hospital cost after infection ($17,603 vs $51,492), and greater length of stay after infection (10.5 vs 20.5 days). After multivariable adjustment, ICU patients with MRSA BSI had significantly increased total hospital cost, hospital cost after infection, and length of stay after infection. However, using a propensity score approach, we found that, among ICU patients, the difference in cost after infection and the difference in length of stay after infection for MRSA, compared with MSSA BSI, were not significant. The differences among non-ICU patients who developed MRSA or MSSA BSI were not significant after multivariable adjustment or by propensity score.Conclusions.On the basis of propensity score, we found that methicillin resistance did not independently increase hospital cost or length of stay after onset ofS. aureusBSI. We believe that use of a propensity score on a comparable subset of patients may be a better method than multivariable adjustment for assessing the impact of methicillin resistance in cohort studies.
Allergic airway inflammation and susceptibility to pneumococcal pneumonia in a murine model with real-timein vivoevaluation
Authors: Kang C-I , Rouse M S , Patel R , Kita H , Juhn Y J 
Published: April 2009

SummaryThe relationship between allergic airway inflammation and pneumococcal pneumonia is not well understood. We assessed susceptibility to experimental pneumococcal pneumonia in mice with and without allergic airway inflammation. Susceptibility to pneumococcal pneumonia was evaluated by challenging mice with a bioluminescent Streptococcus pneumoniae strain after sensitization with ovalbumin (OVA), with subsequent monitoring of pneumococcal infection using real-time photonic imaging. Of 46 OVA-sensitized mice challenged with pneumococci, 13 (28%) developed imaging findings consistent with pneumococcal pneumonia. In comparison, 28 (57%) of 49 non-sensitized control mice developed pneumococcal pneumonia (P = 0·005). While none of the control group developed meningitis (0%, none of 28), two mice in the OVA-sensitized group developed meningitis (15·4%, two of 13) (P = 0·09). The mean bacterial count in the lung was significantly lower in the OVA-sensitized than the non-sensitized group (8·26 ± 0·69 versus 9·21 ± 0·67 log10 colony-forming units (CFU)/g, P = 0·002). There was a trend towards the mean bacterial count in the spleen being higher in the OVA-sensitized versus the non-sensitized group (8·14 ± 0·89 versus 7·45 ± 1·07 log10 CFU/g, P = 0·071). A high level of interleukin (IL)-4 in lung homogenates was associated with risk of pneumococcal infection independent of sensitization with OVA (odds ratio: 49·7, 95% confidence interval 2·92-846·5, per increment of 1·0 pg/ml). In the murine model studied, acute allergic airway inflammation reduced susceptibility to pneumococcal pneumonia. IL-4 may increase the risk of pneumococcal pneumonia independently of allergic airway inflammation.