Rotating star initial data for a constrained scheme in numerical relativity

A new numerical code for computing stationary axisymmetric rapidly rotating stars in general relativity is presented. The formulation is based on a fully constrained-evolution scheme for 3+1 numerical relativity using the Dirac gauge and maximal slicing. We use both the polytropic and MIT bag model equations of state to demonstrate that the code can construct rapidly rotating neutron star and strange star models. We compare numerical models obtained by our code and a well-established code, which uses a different gauge condition, and show that the two codes agree to high accuracy.Comment: Minor changes and one figure added. Version accepted for publication in Class. Quant. Gra

Effects of mowing utilization on forage yield and quality in five oat varieties in alpine area of the eastern Qinghai-Tibetan Plateau

Oat (Avena sativa) is grown to provide feed in winter for livestock production in the alpine area of Qinghai-Tibetan Plateau. The effect of early cutting (T1), late cutting (T2) as well as once cutting andtwice cutting (T3) on forage yields and qualities were investigated for five oat varieties (YTA, CNC, B3, Q473 and Q444). The cutting frequency and time significantly affected forage yield and quality of five varieties with the effects being different among the five varieties. T3 increased hay yield and crude protein yield than T2. The dry hay yield and crude protein yield of T2 were all significantly lower when compared to T1. YTA presented the maximum fresh grass yields, total hay yields and total crude proteinyields under all cutting treatments among five varieties. T3 also improved feed quality on S/L ratio, F/D ratio, CP, CF and CA compared to T2 treatment. The results showed that utilization of two cuttings ofoat artificial grasslands can be used to supply forage for livestock in alpine area. YTA is a good oat introduced variety which has higher hay yield and feeding quality even with two cuttings in alpine area

Distribution of biomass and diversity of Stipa bungeana community to climatic factors in the Loess Plateau of northwestern China

Based on 28 year field data of Stipa bungeana community in arid, semi-arid, semi-humid areas of the Loess Plateau of Northwestern China, we studied species diversity and above ground biomass of S. bungeana community, analyzed the responses of above ground biomass to climate in different areas, and built a model of relationship between biomass and climatic factors. Results showed that there were significant differences for species diversity and above ground biomass among different sampling area. The species diversity range of S. bungeana was from 8.5 - 30.8 (ind/m2), and above ground biomass range was from 407.3 - 817.3 (g/m2) among studied area. The optimal distribution altitude range for S. bungeana is 1400 - 2000 m in arid area, 1200 - 1900 m in semi-arid area, and 600 - 1600 m in semi-humid area. Results also showed that the growth of S. bungeana was affected by different climatic factors, with rainfall as the major factor. Meanwhile, there was a close relationship between monthly biomass and rainfall during the growth stage. The models of monthly biomass and climate were built to compare the results and reveal the relationship between climatic factors and the growth of S. bungeana community.Key words: Stipa bungeana community, biomass model, species diversity, climatic factor, Loess Plateau

A Multi-Phase Transport Model for Relativistic Heavy Ion Collisions

We describe in detail how the different components of a multi-phase transport (AMPT) model, that uses the Heavy Ion Jet Interaction Generator (HIJING) for generating the initial conditions, Zhang's Parton Cascade (ZPC) for modeling partonic scatterings, the Lund string fragmentation model or a quark coalescence model for hadronization, and A Relativistic Transport (ART) model for treating hadronic scatterings, are improved and combined to give a coherent description of the dynamics of relativistic heavy ion collisions. We also explain the way parameters in the model are determined, and discuss the sensitivity of predicted results to physical input in the model. Comparisons of these results to experimental data, mainly from heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC), are then made in order to extract information on the properties of the hot dense matter formed in these collisions.Comment: 33 pages, 38 figures, revtex. Added 9 figures, version published in Phys. Rev. C. The full source code of the AMPT model in the Fortran 77 language and instructions for users are available from the EPAPS ftp site (ftp://ftp.aip.org/epaps/phys_rev_c/E-PRVCAN-72-781512/) and the OSCAR website (http://www-cunuke.phys.columbia.edu/OSCAR/

Dominant-Negative CK2α Induces Potent Effects on Circadian Rhythmicity

Circadian clocks organize the precise timing of cellular and behavioral events. In Drosophila, circadian clocks consist of negative feedback loops in which the clock component PERIOD (PER) represses its own transcription. PER phosphorylation is a critical step in timing the onset and termination of this feedback. The protein kinase CK2 has been linked to circadian timing, but the importance of this contribution is unclear; it is not certain where and when CK2 acts to regulate circadian rhythms. To determine its temporal and spatial functions, a dominant negative mutant of the catalytic alpha subunit, CK2αTik, was targeted to circadian neurons. Behaviorally, CK2αTik induces severe period lengthening (∼33 h), greater than nearly all known circadian mutant alleles, and abolishes detectable free-running behavioral rhythmicity at high levels of expression. CK2αTik, when targeted to a subset of pacemaker neurons, generates period splitting, resulting in flies exhibiting both long and near 24-h periods. These behavioral effects are evident even when CK2αTik expression is induced only during adulthood, implicating an acute role for CK2α function in circadian rhythms. CK2αTik expression results in reduced PER phosphorylation, delayed nuclear entry, and dampened cycling with elevated trough levels of PER. Heightened trough levels of per transcript accompany increased protein levels, suggesting that CK2αTik disturbs negative feedback of PER on its own transcription. Taken together, these in vivo data implicate a central role of CK2α function in timing PER negative feedback in adult circadian neurons

Improving interface bonding of double-skinned CFST columns

It has been demonstrated that high-strength concrete (HSC) is able to improve the strength-to-weight ratio of reinforced concrete columns and maximise the usable areas of tall buildings. However, closely spaced transverse reinforcement needs to be installed to provide stronger confinement for averting brittle failure of HSC. To resolve the problem, double-skinned concrete-filled-steel-tubular (CFST) columns have been advocated, which eliminates the steel congestion problem for better concrete placing and reduces the concrete arching action thus providing a more uniform confining pressure. Despite these advantages, a major shortcoming of double-skinned CFST columns is that imperfect interface bonding occurs in the elastic stage that reduces elastic strength and stiffness. Thus, the authors proposed to adopt external confinement to restrict the lateral dilation of the outer tube of double-skinned CFST columns. To verify the effectiveness of the proposed external rings, a total of 20 double-skinned normal- and high-strength CFST columns were tested. From the test results, it was observed that the stiffness, axial load-carrying capacity and ductility of ringconfined double-skinned CFST columns were significantly higher than the unconfined columns

Adrenal computed tomography and NP-59 usefulness for diagnosing aldosterone-producing adenomas and idiopathic hyperaldosteronism in primary hyperaldosteronism

AbstractObjectivesTwo major causes of primary aldosteronism are aldosterone-producing adenomas (APA) and idiopathic hyperaldosteronism (IHA). In this study, we attempted to determine the role of NP-59 in identifying APA prior to adrenalectomy, especially when diagnostic computer tomography (CT) is equivocal.MethodsWe performed a retrospective analysis in patients with a clinical diagnosis of primary aldosteronism. The medical records of 36 patients were reviewed, which included 25 patients who had received adrenalectomy. All patients underwent adrenal CT alone or a combination of adrenal CT and NP-59 prior to surgery for the subtyping of primary aldosteronism, based on the protocols established in our institution. The accuracy of the adrenal CT and NP-59 findings was determined by a comparison with the pathologic findings and postoperative outcomes.ResultsTwenty-three patients received unilateral adrenalectomy under the diagnosis of APA. The diagnoses were based on CT findings in 11 patients and on CT and NP-59 findings in 12 patients. The results of pathology were adrenal cortical adenoma in these 23 patients and the positive predictive value was 100%. Blood pressure and potassium levels significantly improved after surgery in these patients (p < 0.01). Serum biochemistry and adrenal size of the limbs and bodies of patients with IHA were not significantly different from those of patients with APA.ConclusionFor the subtyping of primary aldosteronism, the imaging modality of adrenal CT alone or the combination of adrenal CT and NP-59 adrenal scan has a high positive predictive value for APAs. We suggest that all patients undergo an adrenal CT as their initial study, after confirming the diagnosis of primary aldosteronism, and to use NP-59 when adrenal CT findings are atypical or inconclusive. Lateralization by this modality prior to adrenalectomy can reduce unnecessarily invasive examinations such as adrenal venous sampling and also provide excellent treatment outcomes

Cross section for charmonium absorption by nucleons

Journals published by the American Physical Society can be found at http://publish.aps.org/The cross section for J/psi absorption by nucleons is studied using a gauged SU(4) hadronic Lagrangian but with empirical particle masses, which has been used previously to study the cross sections for J/psi absorption by pion and rho meson. Including both two-body and three-body final states, we find that with a cutoff parameter of 1 GeV at interaction vertices involving charm hadrons, the J/psi-N absorption cross section is at most 5 mb and is consistent with that extracted from J/psi production from both photonuclear and proton-nucleus reactions