Valley-Polarized Interlayer Conduction of Anisotropic Dirac Fermions in SrMnBi2

We report the valley-selective interlayer conduction of SrMnBi2 under in-plane magnetic fields. The c-axis resistivity of SrMnBi2 shows clear angular magnetoresistance oscillations indicating coherent interlayer conduction. Strong fourfold variation of the coherent peak in the c-axis resistivity reveals that the contribution of each Dirac valley is significantly modulated by the in-plane field orientation. This originates from anisotropic Dirac Fermi surfaces with strong disparity in the momentum-dependent interlayer coupling. Furthermore, we found a signature of broken valley symmetry at high magnetic fields. These findings demonstrate that a quasi-two-dimensional anisotropic Dirac system can host a valley-polarized interlayer current through magnetic valley control. © 2014 American Physical Society.open1

VUV frequency combs from below-threshold harmonics

Recent demonstrations of high-harmonic generation (HHG) at very high repetition frequencies (~100 MHz) may allow for the revolutionary transfer of frequency combs to the vacuum ultraviolet (VUV). This advance necessitates unifying optical frequency comb technology with strong-field atomic physics. While strong-field studies of HHG have often focused on above-threshold harmonic generation (photon energy above the ionization potential), for VUV frequency combs an understanding of below-threshold harmonic orders and their generation process is crucial. Here we present a new and quantitative study of the harmonics 7-13 generated below and near the ionization threshold in xenon gas. We show multiple generation pathways for these harmonics that are manifested as on-axis interference in the harmonic yield. This discovery provides a new understanding of the strong-field, below-threshold dynamics under the influence of an atomic potential and allows us to quantitatively assess the achievable coherence of a VUV frequency comb generated through below threshold harmonics. We find that under reasonable experimental conditions temporal coherence is maintained. As evidence we present the first explicit VUV frequency comb structure beyond the 3rd harmonic.Comment: 16 pages, 4 figures, 1 tabl

Risk Factors for Breast Cancer and Expression of Insulin-Like Growth Factor-2 (IGF-2) in Women with Breast Cancer in Wuhan City, China

PURPOSE: The purpose of this study was to explore the risk factors for breast cancer and establish the expression rate of IGF-2 in female patients. METHODS: A case control study with 500 people in case group and 500 people in control group. A self-administered questionnaire was used to investigate risk factors for breast cancer. All cases were interviewed during a household survey. Immune-histochemical method was used to inspect the expression of IGF-2 in different tissues (benign breast lesions, breast cancer and tumor-adjacent tissue). RESULTS: Multivariate adjusted odds ratios and 95% confidence intervals were calculated using unconditional logistic regression. High body mass index (OR = 1.012,95%CI = 1.008-1.016), working attributes (OR = 1.004, 95%CI = 1.002 = 1.006), long menstrual period (OR = 1.007, 95%CI = 1.005-1.009), high parity OR = 1.003, 95%CI = 1.001-1.005) , frequent artificial abortion (OR = 1.004, 95%CI = 1.001-1.005), family history of cancer (OR = 1.003, 95%CI = 1.000-1.005), period of night shift (OR = 1.003, 95%CI = 1.001-1.006), live in high risk environment (OR = 1.005, 95%CI = 1.002-1.008), and family problems (OR = 1.010, 95%CI = 1.005-1.014) were associated with increased risk for breast cancer. In this study, good sleeping status, positive coping strategies, subjective support, and utility degree of social support were associated with reduced risk for breast cancer (OR = 0.998, 0.997, 0.985, 0.998 respectively; 95%CI = 0.996-1.000, 0.994-1.000, 0.980-0.989, 0.996-1.000, respectively). In benign breast lesions, breast cancer and tumor-adjacent tissue, IGF-2 was mainly expressed in the cytoplasm, but its expression rate was different (p<0.05). CONCLUSIONS: The incidence of breast cancer is a common result of multiple factors. IGF-2 is involved in the development of breast cancer, and its expression varies in different tissues (benign breast lesions, breast cancer and tumor-adjacent tissue)

Multiple ITS Copies Reveal Extensive Hybridization within Rheum (Polygonaceae), a Genus That Has Undergone Rapid Radiation

During adaptive radiation events, characters can arise multiple times due to parallel evolution, but transfer of traits through hybridization provides an alternative explanation for the same character appearing in apparently non-sister lineages. The signature of hybridization can be detected in incongruence between phylogenies derived from different markers, or from the presence of two divergent versions of a nuclear marker such as ITS within one individual.In this study, we cloned and sequenced ITS regions for 30 species of the genus Rheum, and compared them with a cpDNA phylogeny. Seven species contained two divergent copies of ITS that resolved in different clades from one another in each case, indicating hybridization events too recent for concerted evolution to have homogenised the ITS sequences. Hybridization was also indicated in at least two further species via incongruence in their position between ITS and cpDNA phylogenies. None of the ITS sequences present in these nine species matched those detected in any other species, which provides tentative evidence against recent introgression as an explanation. Rheum globulosum, previously indicated by cpDNA to represent an independent origin of decumbent habit, is indicated by ITS to be part of clade of decumbent species, which acquired cpDNA of another clade via hybridization. However decumbent and glasshouse morphology are confirmed to have arisen three and two times, respectively.These findings suggested that hybridization among QTP species of Rheum has been extensive, and that a role of hybridization in diversification of Rheum requires investigation

Discovery of the Onset of Rapid Accretion by a Dormant Massive Black Hole

Massive black holes are believed to reside at the centres of most galaxies. They can be- come detectable by accretion of matter, either continuously from a large gas reservoir or impulsively from the tidal disruption of a passing star, and conversion of the gravitational energy of the infalling matter to light. Continuous accretion drives Active Galactic Nuclei (AGN), which are known to be variable but have never been observed to turn on or off. Tidal disruption of stars by dormant massive black holes has been inferred indirectly but the on- set of a tidal disruption event has never been observed. Here we report the first discovery of the onset of a relativistic accretion-powered jet in the new extragalactic transient, Swift J164449.3+573451. The behaviour of this new source differs from both theoretical models of tidal disruption events and observations of the jet-dominated AGN known as blazars. These differences may stem from transient effects associated with the onset of a powerful jet. Such an event in the massive black hole at the centre of our Milky Way galaxy could strongly ionize the upper atmosphere of the Earth, if beamed towards us.Comment: Submitted to Nature. 4 pages, 3 figures (main paper). 26 pages, 13 figures (supplementary information

Nonbacterial thrombotic endocarditis associated with cancer of unknown origin complicated with thrombus in the left auricular appendage: case report

A 63-year-old man was admitted to our hospital with a complaint of right lateroabdominal pain. He was diagnosed with metastatic colon cancer, and then developed multiple brain embolic infarctions 7 days after admission. Transesophageal echocardiography showed that mobile, echo-dense masses were attached to the anterior and posterior mitral valve leaflet. Furthermore, there was a thrombus in the left auricular appendage despite sinus rhythm. These findings led to a diagnosis of suspected infectious endocarditis with subsequent multiple brain infarctions. The patient's general condition worsened and he died 13 days after admission. An autopsy was performed, and, while poorly differentiated cancer was observed in multiple organs, no primary tumor could be identified. Histological analysis showed that the masses of the mitral valve consisted mainly of fibrin without bacteria or oncocytes. This patient was therefore diagnosed with nonbacterial thrombotic endocarditis associated with cancer of unknown origin complicated with thrombus in the left auricular appendage

A Bayesian Partition Method for Detecting Pleiotropic and Epistatic eQTL Modules

Studies of the relationship between DNA variation and gene expression variation, often referred to as “expression quantitative trait loci (eQTL) mapping”, have been conducted in many species and resulted in many significant findings. Because of the large number of genes and genetic markers in such analyses, it is extremely challenging to discover how a small number of eQTLs interact with each other to affect mRNA expression levels for a set of co-regulated genes. We present a Bayesian method to facilitate the task, in which co-expressed genes mapped to a common set of markers are treated as a module characterized by latent indicator variables. A Markov chain Monte Carlo algorithm is designed to search simultaneously for the module genes and their linked markers. We show by simulations that this method is more powerful for detecting true eQTLs and their target genes than traditional QTL mapping methods. We applied the procedure to a data set consisting of gene expression and genotypes for 112 segregants of S. cerevisiae. Our method identified modules containing genes mapped to previously reported eQTL hot spots, and dissected these large eQTL hot spots into several modules corresponding to possibly different biological functions or primary and secondary responses to regulatory perturbations. In addition, we identified nine modules associated with pairs of eQTLs, of which two have been previously reported. We demonstrated that one of the novel modules containing many daughter-cell expressed genes is regulated by AMN1 and BPH1. In conclusion, the Bayesian partition method which simultaneously considers all traits and all markers is more powerful for detecting both pleiotropic and epistatic effects based on both simulated and empirical data

Cloning and Characterization of a Putative TAC1 Ortholog Associated with Leaf Angle in Maize (Zea mays L.)

BACKGROUND: Modifying plant architecture to increase photosynthesis efficiency and reduce shade avoidance response is very important for further yield improvement when crops are grown in high density. Identification of alleles controlling leaf angle in maize is needed to provide insight into molecular mechanism of leaf development and achieving ideal plant architecture to improve grain yield. METHODOLOGY/PRINCIPAL FINDINGS: The gene cloning was done by using comparative genomics, and then performing real-time polymerase chain reaction (RT-PCR) analysis to assay gene expression. The gene function was validated by sequence dissimilarity analysis and QTL mapping using a functional cleaved amplified polymorphism (CAP). CONCLUSIONS: The leaf angle is controlled by a major quantitative trait locus, ZmTAC1 (Zea mays L. Leaf Angle Control 1). ZmTAC1 has 4 exons encoding a protein with 263 amino acids, and its domains are the same as those of the rice OsTAC1 protein. ZmTAC1 was found to be located in the region of qLA2 by using the CAP marker and the F(2:3) families from the cross between Yu82 and Shen137. Real-time PCR analysis revealed ZmTAC1 expression was the highest in the leaf-sheath pulvinus, less in the leaf and shoot apical meristem, and the lowest in the root. A nucleotide difference in the 5'-untranslated region (UTR) between the compact inbred line Yu82 ("CTCC") and the expanded inbred line Shen137 ("CCCC") influences the expression level of ZmTAC1, further controlling the size of the leaf angle. Sequence verification of the change in the 5'-UTR revealed ZmTAC1 with "CTCC" was present in 13 compact inbred lines and ZmTAC1 with "CCCC" was present in 18 expanded inbred lines, indicating ZmTAC1 had been extensively utilized in breeding with regard to the improvement of the maize plant architecture

The prevalence of metabolic syndrome and cardiovascular risk factors in adults in southern China

<p>Abstract</p> <p>Background</p> <p>The metabolic syndrome has been shown to increase the incidence of cardiovascular disease. Little information exists on the prevalence of the metabolic syndrome for southern Chinese. We therefore investigate the prevalence of the metabolic syndrome in a southern Chinese population with 85 million residents.</p> <p>Methods</p> <p>The Guangdong Nutrition and Health Survey 2002 is a cross-sectional survey designed to assess the health and nutritional status of 85 million residents in Guangdong province located in southern China. Stratified multistage random sampling method was applied in this survey and a provincial representative sample of 6,468 residents aged 20 years or above was obtained in the present study. The participants received a full medical check-up including measurement of blood pressure, obesity indices, fasting lipids and glucose levels. Data describing socioeconomic and lifestyle factors was also collected through interview. Metabolic syndrome was defined in accordance with the International Diabetes Federation criteria.</p> <p>Results</p> <p>The prevalence of metabolic syndrome was 7.30%, translating into a total of 4.0 million residents aged 20 years or above having the condition in this southern Chinese population. The urban population had higher prevalence of the syndrome than the rural population (10.57% vs 4.30%). Females had a higher prevalence of metabolic syndrome than males (8.99% vs 5.27%). More than 60% of the adults had at least one component of the metabolic syndrome.</p> <p>Conclusions</p> <p>Our results indicate that a large proportion of southern Chinese adults have the metabolic syndrome and associated risk factors. The metabolic syndrome has become an important public health problem in China. These findings emphasize the urgent need to develop population level strategies for the prevention, detection, and treatment of cardiovascular risk in China.</p