Rotational and vibrational spectra of quantum rings

One can confine the two-dimensional electron gas in semiconductor heterostructures electrostatically or by etching techniques such that a small electron island is formed. These man-made ``artificial atoms'' provide the experimental realization of a text-book example of many-particle physics: a finite number of quantum particles in a trap. Much effort was spent on making such "quantum dots" smaller and going from the mesoscopic to the quantum regime. Far-reaching analogies to the physics of atoms, nuclei or metal clusters were obvious from the very beginning: The concepts of shell structure and Hund's rules were found to apply -- just as in real atoms! In this Letter, we report the discovery that electrons confined in ring-shaped quantum dots form rather rigid molecules with antiferromagnetic order in the ground state. This can be seen best from an analysis of the rotational and vibrational excitations

The Local Bubble and Interstellar Material Near the Sun

The properties of interstellar matter (ISM) at the Sun are regulated by our location with respect to the Local Bubble (LB) void in the ISM. The LB is bounded by associations of massive stars and fossil supernovae that have disrupted natal ISM and driven intermediate velocity ISM into the LB interior void. The Sun is located in such a driven ISM parcel. The Local Fluff has a bulk velocity of 19 km/s in the LSR, and an upwind direction towards the center of the gas and dust ring formed by the Loop I supernova remnant interaction with the LB. When the ram pressure of the LIC is included in the total LIC pressure, and if magnetic thermal and cosmic ray pressures are similar, the LIC appears to be in pressure equilibrium with the local hot bubble plasma.Comment: Proceedings of Symposium on the Composition of Matter, honoring Johannes Geiss on the occasion of his 80th birthday. Space Science Reviews (in press

Spin- and charge-density oscillations in spin chains and quantum wires

We analyze the spin- and charge-density oscillations near impurities in spin chains and quantum wires. These so-called Friedel oscillations give detailed information about the impurity and also about the interactions in the system. The temperature dependence of these oscillations explicitly shows the renormalization of backscattering and conductivity, which we analyze for a number of different impurity models. We are also able to analyze screening effects in one dimension. The relation to the Kondo effect and experimental consequences are discussed.Comment: Final published version. 15 pages in revtex format including 22 epsf-embedded figures. The latest version in PDF format is available from http://fy.chalmers.se/~eggert/papers/density-osc.pd

Prognostic importance of anaemia in HIV type-1-infected patients starting antiretroviral therapy: collaborative analysis of prospective cohort studies

Background: In HIV type-1-infected patients starting highly active antiretroviral therapy (HAART), the prognostic value of haemoglobin when starting HAART, and of changes in haemoglobin levels, are not well defined. Methods: We combined data from 10 prospective studies of 12,100 previously untreated individuals (25% women). A total of 4,222 patients (35%) were anaemic: 131 patients (1.1%) had severe (<8.0 g/dl), 1,120 (9%) had moderate (male 8.0-<11.0 g/dl and female 8.0-<10.0g/dl) and 2,971 (25%) had mild (male 11.0-<13.0g/dl and female 10.0-<12.0 g/dl) anaemia. We separately analysed progression to AIDS or death from baseline and from 6 months using Weibull models, adjusting for CD4+ T-cell count, age, sex and other variables. Results: During 48,420 person-years of follow-up 1,448 patients developed at least one AIDS event and 857 patients died. Anaemia at baseline was independently associated with higher mortality: the adjusted hazard ratio (95% confidence interval) for mild anaemia was 1.42 (1.17-1.73), for moderate anaemia 2.56 (2.07-3.18) and for severe anaemia 5.26 (3.55-7.81). Corresponding figures for progression to AIDS were 1.60 (1.37-1.86), 2.00 (1.66-2.40) and 2.24 (1.46-3.42). At 6 months the prevalence of anaemia declined to 26%. Baseline anaemia continued to predict mortality (and to a lesser extent progression to AIDS) in patients with normal haemoglobin or mild anaemia at 6 months. Conclusions: Anaemia at the start of HAART is an important factor for short- and long-term prognosis, including in patients whose haemoglobin levels improved or normalized during the first 6 months of HAART

Static and Dynamic Load Deflection Tests of Steel Structures

The results of four phases of a study of the resistance of structural steel frames and frame components are described in this report. Three of the phases, the study of full-scale beam-columns laterally loaded in a principal direction, the model frame study, and the study of obliquely loaded full-scale beam-columns, are concerned with the investigation of static resistance. The fourth phase is concerned with the nature of dynamic resistance of beams. The purpose of this program is to obtain the structural parameters necessary to define the resistance of buildings and building components to blast loading. The static resistances, as measured in tests of the beam-columns and frames, are compared with the resistances predicted using the elasto-plastic theory and an extension of this theory to include the effect of strain hardening. In all studies described the influence of constant axial loads is discussed and techniques for including this effect in the analysis are presented except for the case of the oblique loading study. The last section of this report describes the results of a dynamic test of a simply-supported beam and the analytical studies undertaken in conjunction with this test. A criterion for determining the dynamic yield stress, based on available information on the delay time for yielding, is described and applied to the data obtained in the test. Two possible forms for the dynamic resistance of the beam after yielding are discussed and a comparison of the measured response with the response predicted assuming these forms of the resistance is made.Wright Air Force Development Center. United States Air Force.Contract No. AF 33(616)-170Expenditure Order No. R 449-37 AW-

Robustness of the maladaptive personality plaster: An investigation of stability of the PSY-5-r in adults over 20 years

The long-term stability of maladaptive personality traits in the general population has been under-investigated. The current study examined the longitudinal 20-year mean-level stability and rank-order consistency of five maladaptive personality traits - as measured with the Personality Psychopathology-5-r scales. Correlations and regression analysis were conducted to test both types of stability comparing raw scores of scale administrations in a general population sample in both 1992 and 2012 (N = 65). Repeated measures analysis of variance demonstrated significant mean-level stability of the PSY-5-r traits over 20 years. The PSY-5-r scales demonstrated significant rank-order consistency as evidenced by correlational analyses and reliability coefficients. The scales Aggressiveness-r (r = .73), Neuroticism/Negative Emotionality-r (r = .65), Introversion/Low Positive Emotionality-r (r = .63), and Disconstraint-r (r = .56), evidenced strong rank-order stability, whereas Psychoticism-r (r = .3) showed moderate rank-order consistency. The results of the present study indicate that maladaptive personality traits as measured with the PSY-5-r scales are relatively stable over 20 years in an adult community population

Trait polarity of the Personality Psychopathology 5 (PSY-5-r): A content analysis in relation to the patient description form

The maladaptive trait model of personality has gained popularity in the assessment of personality pathology. The Minnesota Multiphasic Personality Inventory (MMPI-2-RF) is a widely used instrument to measure maladaptive traits, by means of the Personality Psychopathology 5 (PSY-5-r) scales. Polarity of these maladaptive trait measures - whether these traits are unipolar or bipolar maladaptive - has not been empirically established in the literature. In a clinical sample (N = 275), we investigated content polarity of these traits in relation to 25 psychological symptoms, measured by the Patient Description Form. Hierarchical regression analyses were applied to compare linear and curvilinear models and determine optimal fit. The results provided evidence for content unipolarity of all five traits, with small exceptions. We conclude that, in practice, the MMPI-2-RF PSY-5-r scales do not assess the PSY-5 theoretical model as expected, such that the higher the score on these scales the more it is likely impairing or impacting daily functioning. Conceptual and clinical implications are discussed