773 research outputs found
Astrophysical observables for regular black holes with sub-Planckian curvature
We investigate the photon sphere and the extremal stable circular orbit
(ESCO) for massive particles over a recently proposed regular black holes with
sub-Planckian curvature and Minkowskian core. We derive the effective potential
for geodesic orbits and determine the radius of circular photon orbits, with an
analysis on the stability of these orbits. We extend our analysis to the
background of compact massive object (CMO) without horizon, whose mass is below
the lowest bound for the formation of a black hole. For massive particles, the
ESCOs become double-valued in CMO phase and we calculate the innermost stable
circular orbits (ISCO) and the outermost stable circular orbits (OSCO). By
comparing wih Bardeen black hole and Hayward black hole, it is also found that
the locations of photon sphere and ESCO in CMO phase with Minkowskian core are
evidently different from the ones in CMO phase with dS core, which potentially
provides a way to distinguish these two sorts of black holes by astronomical
observation.Comment: V1:23pages,8figures,V2:Changed the annotation format of figure 3, two
clerical errors were corrected on pages 18,19, no physics change
Accretion Disk for regular black holes with sub-Planckian curvature
We investigate the accretion disk for a sort of regular black holes which are
characterized by sub-Planckian curvature and Minkowskian core. We derive null
geodesics outside the horizon of such regular black holes and analyze the
feature of the light rays from the accretion disk which can be classified into
direct emission, lensed rings, and photon rings. We find that the observed
brightness under different emission models is mainly determined by direct
emission, while the contribution from the flux of the lensed and photon rings
is limited. By comparing with Bardeen black hole with a dS core, it is found
that the black hole with a Minkowskian core exhibits distinct astronomical
optical features when surrounded by accretion disk, which potentially provides
a way to distinguish these two sorts of black holes by astronomical
observation.Comment: 26 pages,9 figure
Poly[diaquabis(μ3-1H-benzimidazole-5,6-dicarboxylato-κ4 N 3:O 5,O 5′:O 6)bis(μ2-1H,3H-benzimidazolium-5,6-dicarboxylato-κ3 O 5,O 5′:O 6)digadolinium(III)]
In the title complex, [Gd2(C9H4N2O4)2(C9H5N2O4)2(H2O)2]n, two of the benzimidazole-5,6-dicarboxylate ligands are protonated at the imidazole groups. Each GdIII ion is coordinated by six O atoms and one N atom from five ligands and one water molecule, displaying a distorted bicapped trigonal-prismatic geometry. The GdIII ions are linked by the carboxylate groups and imidazole N atoms, forming a layer parallel to (001). These layers are further connected by O—H⋯O and N—H⋯O hydrogen bonds into a three-dimensional supramolecular network
Risk for Gestational Diabetes Mellitus and Adverse Birth Outcomes in Chinese Women with Polycystic Ovary Syndrome
Objective. To examine the association of polycystic ovary syndrome (PCOS) in early pregnancy with gestational diabetes mellitus (GDM) and adverse birth outcomes. Methods. In this retrospective cohort study including 2389 pregnant women, the medical records of 352 women diagnosed with PCOS were evaluated. Outcomes included GDM, preterm birth, low birth weight, macrosomia, and being small and large for gestational age. Multivariable logistic regression models were used to examine the association of the risk for GDM and adverse birth outcomes with PCOS after adjusting for confounders. Results. Women previously diagnosed with PCOS had a higher risk of GDM (adjusted odds ratio [OR] 1.55, 95% confidence interval [CI]: 1.14–2.09). A strong association was seen between PCOS and preterm birth (adjusted OR 1.69, 95% CI: 1.08–2.67). On stratified analysis, the adjusted OR for GDM among women with PCOS undergoing assisted reproductive technology was 1.44 (95% CI: 1.03–1.92) and among women with PCOS who conceived spontaneously was 1.60 (1.18–2.15). No increased risk for other adverse birth outcomes was observed. Conclusions. Women with PCOS were more likely to experience GDM and preterm birth
Poly[(6-carboxypicolinato-κ3 O 2,N,O 6)(μ3-pyridine-2,6-dicarboxylato-κ5 O 2,N,O 6:O 2′:O 6′)dysprosium(III)]
In the title complex, [Dy(C7H3NO4)(C7H4NO4)]n, one of the ligands is fully deprotonated while the second has lost only one H atom. Each DyIII ion is coordinated by six O atoms and two N atoms from two pyridine-2,6-dicarboxylate and two 6-carboxypicolinate ligands, displaying a bicapped trigonal-prismatic geometry. The average Dy—O bond distance is 2.40 Å, some 0.1Å longer than the corresponding Ho—O distance in the isotypic holmium complex. Adjacent DyIII ions are linked by the pyridine-2,6-dicarboxylate ligands, forming a layer in (100). These layers are further connected by π–π stacking interactions between neighboring pyridyl rings [centroid–centroid distance = 3.827 (3) Å] and C—H⋯O hydrogen-bonding interactions, assembling a three-dimensional supramolecular network. Within each layer, there are other π–π stacking interactions between neighboring pyridyl rings [centroid–centroid distance = 3.501 (2) Å] and O—H⋯O and C—H⋯O hydrogen-bonding interactions, which further stabilize the structure
A saúde mental é o fator mais importante que influencia a qualidade de vida de idosos deixados para trás quando as famílias emigram da China rural
OBJECTIVES: to investigate the quality of life and the associated factors on left behind elderly in rural China. METHOD: the research was conducted cluster sampling to select 456 elderly left behind when family members migrated out of rural China to participate in a cross-sectional study by completing a general data questionnaire and Quality of Life questionnaire. RESULTS: 91.5% of the elderly requested psychological counseling and education. For the elderly, scores for mental health (39.56±13.73) were significantly lower compared with Chinese standard data (61.6±13.7) (POBJETIVOS: investigar la calidad de vida y los factores asociados a los adultos mayores que se quedan en las zonas rurales de China. MÉTODO: la investigación se realizó por medio de muestreo por conglomerados para seleccionar 456 adultos mayores que se quedaron cuando los miembros de la familia emigraron de zonas rurales de China, para participar en un estudio de corte transversal, completando un cuestionario de datos generales y cuestionario de calidad de vida. RESULTADOS: el 91.5% de los adultos mayores solicitó asistencia psicológica y educación. Para los adultos mayores, las puntuaciones de salud mental (39.56±13.73) fueron significativamente más bajos en comparación con los datos estándar de China (61.6±13.7) (pOBJETIVOS: investigar a qualidade de vida e fatores associados de idosos deixados para trás na China rural. MÉTODO: foi realizada amostragem por conglomerado para selecionar 456 idosos deixados para trás quando os membros da família emigram da China rural. Este é um estudo transversal com preenchimento de um questionário de dados gerais e de qualidade de vida. RESULTADOS: 91,5% dos idosos convidados solicitaram aconselhamento e educação psicológicos. Para os idosos, os escores de saúde mental (39,56±13,73) foram significativamente menores em comparação aos dados padrões chineses (61,6±13,7) (
Reducing the aerodynamic drag of high-speed trains by air blowing from the nose part: Effect of blowing speed
To reduce the aerodynamic drag of high-speed trains, this work proposes an air blowing configuration on the head and tail cars of high-speed trains. The variation in the aerodynamic drag and slipstream velocity is analyzed under different blowing velocities, and the flow mechanism for train aerodynamic performance alteration is explained. The results show that under the blowing speeds of Ub = 0.05Ut, 0.10Ut, 0.15Ut, and 0.20Ut, where Ut is the train speed, the total drag coefficient (Cd) decreases by 5.81%, 10.78%, 13.70%, and 15.43% compared to the without-blowing case, respectively. However, with the increase in the blowing speed, the reduction trend of Cd tends to be smoother; namely, the decrement ratio compared to the previous blowing speed for the head car is 9.08%, 0.11%, 0.60%, and 1.14% for Ub = 0.05Ut, 0.10Ut, 0.15Ut, and 0.20Ut, respectively. The blowing measure generates an air gap between the coming flow and train surface, consequently causing a reduction in the viscous and pressure drag. In addition, the structure size and strength of the wake flow under different blowing cases show a decreasing trend from Ub = 0.00Ut to 0.10Ut and then an increasing trend from Ub = 0.10Ut to 0.20Ut. Thus, considering the blowing cost, efficiency, and flow structure evolution comprehensively, the case of Ub = 0.10Ut is recommended. Under this blowing speed, the reduction ratio of the aerodynamic drag is 9.18%, 12.77%, 10.90%, and 10.78% for the head, middle, tail car, and total train, respectively
Identification and association of the single nucleotide polymorphisms in calpain3 (CAPN3) gene with carcass traits in chickens
<p>Abstract</p> <p>Background</p> <p>The aim of this study is to screen single nucleotide polymorphisms (SNP) of chicken <it>Calpain3 </it>(<it>CAPN3</it>) gene and to analyze the potential association between <it>CAPN3 </it>gene polymorphisms and carcass traits in chickens. We screened <it>CAPN3 </it>single nucleotide polymorphisms (SNP) in 307 meat-type quality chicken from 5 commercial pure lines (S01, S02, S03, S05, and D99) and 4 native breeds from Guangdong Province (Huiyang Huxu chicken and Qingyuan Ma chicken) and Sichuan Province (Caoke chicken and Shandi Black-bone chicken), China.</p> <p>Results</p> <p>Two SNPs (11818T>A and 12814T>G) were detected by single strand conformation polymorphism (SSCP) method and were verified by DNA sequencing. Association analysis showed that the 12814T>G genotypes were significantly associated with body weight (BW), carcass weight (CW), breast muscle weight (BMW), and leg muscle weight (LMW). Haplotypes constructed on the two SNPs (H1, TG; H2, TT; H3, AG; and H4, AT) were associated with BW, CW (<it>P </it>< 0.05), eviscerated percentage (EP), semi-eviscerated percentage (SEP), breast muscle percentage (BMP), and leg muscle percentage (LMP) (<it>P </it>< 0.01). Diplotype H1H2 was dominant for BW, CW, and LMP, and H2H2 was dominant for EP, SEP, and BMP.</p> <p>Conclusion</p> <p>We speculated that the <it>CAPN3 </it>gene was a major gene affecting chicken muscle growth and carcass traits or it was linked with the major gene(s). Diplotypes H1H2 and H2H2 might be advantageous for carcass traits.</p
Tissue-Specific Expression of the Chicken Calpain2 Gene
We quantified chicken calpain 2 (CAPN2) expression in two Chinese chicken breeds (mountainous black-bone chicken breed [MB] and a commercial meat type chicken breed [S01]) to discern the tissue and ontogenic expression pattern and its effect on muscle metabolism. Real-time quantitative PCR assay was developed for accurate measurement of the CAPN2 mRNA expression in various tissues from chickens of different ages (0, 2, 4, 6, 8, 10, and 12 weeks). Results showed that the breast muscle and leg muscle tissues had the highest expression of CAPN2 compared to the other tissues from the same individual (P < .05). Overall, the CAPN2 mRNA level exhibited a “rise” developmental change in all tissues. The S01 chicken had a higher expression of the CAPN2 mRNA in all tissues than the MB chicken. Our results suggest that chicken CAPN2 expression may be related to chicken breeds and tissues
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