University of Texas at Austin

About: University of Texas at Austin is a education organization based out in Austin, Texas, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 94352 authors who have published 206297 publications receiving 9070052 citations. The organization is also known as: UT-Austin & UT Austin.

Valley-dependent optoelectronics from inversion symmetry breaking

Abstract: Inversion symmetry breaking allows contrasted circular dichroism in different $k$-space regions, which takes the extreme form of optical selection rules for interband transitions at high symmetry points. In materials where band edges occur at noncentral valleys, this enables valley-dependent interplay of electrons with light of different circular polarizations, in analogy to spin dependent optical activities in semiconductors. This discovery is in perfect harmony with the previous finding of valley contrasted Bloch band features of orbital magnetic moment and Berry curvatures from inversion symmetry breaking [D. Xiao, W. Yao, and Q. Niu, Phys. Rev. Lett. 99, 236809 (2007)]. A universal connection is revealed between the $k$-resolved optical oscillator strength of interband transitions, the orbital magnetic moment and the Berry curvatures, which also provides a principle for optical measurement of orbital magnetization and intrinsic anomalous Hall conductivity in ferromagnetic systems. The general physics is demonstrated in graphene where inversion symmetry breaking leads to valley contrasted optical selection rule for interband transitions. We discuss graphene based valley optoelectronics applications where light polarization information can be interconverted with electronic information.

Information technology relatedness, knowledge management capability, and performance of multibusiness firms

Abstract: Business value of information technology is an enduring research question. The elusive link between IT and financial firm performance calls for further research into intermediate organizational variables through which IT may influence firm performance. This study proposes that knowledge management (KM) is a critical organizational capability through which IT influences firm performance. In the context of multibusiness firms, the study examines how the IT resources of a firm should be organized and managed to enhance the firm's KM capability, and whether and how KM capability influences firm performance. The study develops two hypothesizes: (1) IT relatedness of the firm's business units enhances cross-unit KM capability; (2) KM capability, in turn, leads to superior firm performance. Data from 250 Fortune 1000 firms provide empirical support for these hypotheses. IT relatedness of business units enhances the cross-unit KM capability of the firm. The KM capability creates and exploits cross-unit synergies from the product, customer, and managerial knowledge resources of the firm. These synergies increase the financial performance of the firm. IT relatedness also has significant indirect effects on firm performance through the mediation of KM capability.

The Inventory of Depressive Symptomatology, Clinician Rating (IDS-C) and Self-Report (IDS-SR), and the Quick Inventory of Depressive Symptomatology, Clinician Rating (QIDS-C) and Self-Report (QIDS-SR) in public sector patients with mood disorders: a psychometric evaluation.

Abstract: Background. The present study provides additional data on the psychometric properties of the 30-item Inventory of Depressive Symptomatology (IDS) and of the recently developed Quick Inventory of Depressive Symptomatology (QIDS), a brief 16-item symptom severity rating scale that was derived from the longer form. Both the IDS and QIDS are available in matched clinician-rated (IDS-C 30 ; QIDS-C 16 ) and self-report (IDS-SR 30 ; QIDS-SR 16 ) formats. Method. The patient samples included 544 out-patients with major depressive disorder (MDD) and 402 out-patients with bipolar disorder (BD) drawn from 19 regionally and ethnicically diverse clinics as part of the Texas Medication Algorithm Project (TMAP). Psychometric analyses including sensitivity to change with treatment were conducted. Results. Internal consistencies (Cronbach's alpha) ranged from 0.81 to 0.94 for all four scales (QIDS-C 16 , QIDS-SR 16 , IDS-C30 and IDS-SR 30 ) in both MDD and BD patients. Sad mood, involvement, energy, concentration and self-outlook had the highest item-total correlations among patients with MDD and BD across all four scales. QIDS-SR 16 and IDS-SR 30 total scores were highly correlated among patients with MDD at exit (c=0.83). QIDS-C 16 and IDS-C 30 total scores were also highly correlated among patients with MDD (c=0.82) and patients with BD (c=0.81). The IDS-SR 30 , IDS-C 30 , QIDS-SR 16 , and QIDS-C 16 were equivalently sensitive to symptom change, indicating high concurrent validity for all four scales. High concurrent validity was also documented based on the SF-12 Mental Health Summary score for the population divided in quintiles based on their IDS or QIDS score. Conclusion. The QIDS-SR 16 and QIDS-C 16 , as well as the longer 30-item versions, have highly acceptable psychometric properties and are treatment sensitive measures of symptom severity in depression.

Line formation in solar granulation IV. (O I), O I and OH lines and the photospheric O abundance

Abstract: The solar photospheric oxygen abundance has been determined from (O I), O I, OH vibration-rotation and OH pure rotation lines by means of a realistic time-dependent, 3D, hydrodynamical model of the solar atmosphere. In the case of the O I lines, 3D non-LTE calculations have been performed, revealing significant departures from LTE as a result of photon loss es in the lines. We derive a solar oxygen abundance of log ǫO = 8.66 ± 0.05. All oxygen diagnostics yield highly consistent abundances, in sharp contrast with the results of classical 1D model atmospheres. This low value is in good agreement with measurements of the local interstellar medium and nearby B stars. This low abundance is also supported by the excellent correspondence between lines of very different line formation sensitivities, and between the observed and predicted line shapes and center-to-limb variations. Together with the corresponding down-ward revisions of the solar carbon, nitrogen and neon abundances, the resulting significant decrease in solar met al mass fraction to Z = 0.0126 can, however, potentially spoil the impressive agreement between predicted and observed sound speed in the solar interior determined from helioseismology.