The extended star formation history of omega Centauri

For the first time, the abundances of a large sample of subgiant and turn-off region stars in omega Centauri have been measured, the data base being medium resolution spectroscopy from FORS2 at the VLT. Absolute iron abundances were derived for about 400 member stars from newly defined line indices with an accuracy of +/-0.15 dex. The abundances range between -2.2<[Fe/H]<-0.7 dex, resembling the large metallicity spread found for red giant branch stars. The combination of the spectroscopic results with the location of the stars in the colour magnitude diagram has been used to estimate ages for the individual stars. Whereas most of the metal-poor stars are consistent with a single old stellar population, stars with abundances higher than [Fe/H]=-1.3 dex are younger. The total age spread in omega Cent is about 3 Gyr. The monotonically increasing age-metallicity relation seems to level off above [Fe/H]=-1.0 dex. Whether the star formation in omega Cen occured continuously or rather episodically has to be shown by combining more accurate abundances with highest quality photometry.Comment: 4 pages, 3 figures, accepted for publication in Astronomy & Astrophysics (Letters

Critical State Flux Penetration and Linear Microwave Vortex Response in YBa_2Cu_3O_{7-x} Films

The vortex contribution to the dc field (H) dependent microwave surface impedance Z_s = R_s+iX_s of YBa_2Cu_3O_{7-x} thin films was measured using suspended patterned resonators. Z_s(H) is shown to be a direct measure of the flux density B(H) enabling a very precise test of models of flux penetration. Three regimes of field-dependent behavior were observed: (1) Initial flux penetration occurs on very low field scales H_i(4.2K) 100Oe, (2) At moderate fields the flux penetration into the virgin state is in excellent agreement with calculations based upon the field-induced Bean critical state for thin film geometry, parametrized by a field scale H_s(4.2K) J_c*d 0.5T, (3) for very high fields H >>H_s, the flux density is uniform and the measurements enable direct determination of vortex parameters such as pinning force constants \alpha_p and vortex viscosity \eta. However hysteresis loops are in disagreement with the thin film Bean model, and instead are governed by the low field scale H_i, rather than by H_s. Geometric barriers are insufficient to account for the observed results.Comment: 20 pages, LaTeX type, Uses REVTeX style files, Submitted to Physical Review B, 600 dpi PostScript file with high resolution figures available at http://sagar.physics.neu.edu/preprints.htm

Beyond Prejudice as Simple Antipathy: Hostile and Benevolent Sexism Across Cultures

The authors argue that complementary hostile and benevolent componen:s of sexism exist ac ro.ss cultures. Male dominance creates hostile sexism (HS). but men's dependence on women fosters benevolent sexism (BS)-subjectively positive attitudes that put women on a pedestal but reinforce their subordination. Research with 15,000 men and women in 19 nations showed that (a) HS and BS are coherenl constructs th at correlate positively across nations, but (b) HS predicts the ascription of negative and BS the ascription of positive traits to women, (c) relative to men, women are more likely to reject HS than BS. especially when overall levels of sexism in a culture are high, and (d) national averages on BS and HS predict gender inequal ity across nations. These results challenge prevailing notions of prejudice as an antipathy in that BS (an affectionate, patronizing ideology) reflects inequality and is a cross-culturally pervasive complement to HS

The Psychobiology of Authentic and Simulated Dissociative Personality States:The Full Monty

The etiology of dissociative identity disorder (DID) remains a topic of debate. Proponents of the fantasy model and the trauma model of DID have both called for more empirical research. To this end, the current study presents new and extended data analyses of a previously published (H2O)-O-15 positron emission tomography imaging study. This study included 29 subjects: 11 patients with DID and 10 high- and 8 low-fantasy-prone DID-simulating mentally healthy control subjects. All subjects underwent an autobiographical memory script-driven (neutral and trauma related) imagery paradigm in 2 (simulated) dissociative personality states (neutral and trauma related). Psychobiological and psychophysiological data were obtained. Results of the new post-hoc tests on the psychophysiological responses support the trauma model. New results of the brain imaging data did not support the fantasy model. This study extends previously published results by offering important new supporting data for the trauma model of DID.</p

Microwave Current Imaging in Passive HTS Components by Low-Temperature Laser Scanning Microscopy (LTLSM)

We have used the LTLSM technique for a spatially resolved investigation of the microwave transport properties, nonlinearities and material inhomogeneities in an operating coplanar waveguide YBa_2Cu_3O_{7-\delta} (YBCO) microwave resonator on an LaAlO_3 (LAO) substrate. The influence of twin-domain blocks, in-plane rotated grains, and micro-cracks in the YBCO film on the nonuniform rf current distribution were measured with a micrometer-scale spatial resolution. The impact of the peaked edge currents and rf field penetration into weak links on the linear device performance were studied as well. The LTLSM capabilities and its future potential for non-destructive characterization of the microwave properties of superconducting circuits are discussed.Comment: 8 pages, 9 figures, 2-column format, presented at High Temperature Superconductors in High Frequency Fields 2004, Journal of Superconductivity (in press

Beklag over niet vervolgen:Het gaat het Openbaar Ministerie om met art. 12 Sv-zaken?

Een aangifte van een strafbaar feit door een burger leidt vaak niet tot een strafvervolging. De officier van justitie kan beslissen dat de zaak niet aan de rechter wordt voorgelegd, maar wordt geseponeerd. Tegen deze beslissing kan de belanghebbende zich op grond van artikel 12 Wetboek van Strafvordering beklagen bij het gerechtshof. Dit boek bevat een verslag van een onderzoek naar de praktijk van deze beklagprocedure en de kwaliteit van het werk van het Openbaar Ministerie. De centrale vraag in het onderzoek is of het werk van het Openbaar Misisterie in de beklagprocedure beantwoordt aan de kwaliteitseisen die daaraan mogen worden gesteld. Relevante informatie is verkregen door een kwantitatieve analyse van beklagzaken over de jaren 2010-2014, een uitvoerig dossieronderzoek en interviews met functionarissen die betrokken zijn bij een afhandeling van beklagzaken

Decreased blood–brain barrier P-glycoprotein function in the progression of Parkinson’s disease, PSP and MSA

Decreased blood–brain barrier (BBB) efflux function of the P-glycoprotein (P-gp) transport system could facilitate the accumulation of toxic compounds in the brain, increasing the risk of neurodegenerative pathology such as Parkinson’s disease (PD). This study investigated in vivo BBB P-gp function in patients with parkinsonian neurodegenerative syndromes, using [11C]-verapamil PET in PD, PSP and MSA patients. Regional differences in distribution volume were studied using SPM with higher uptake interpreted as reduced P-gp function. Advanced PD patients and PSP patients had increased [11C]-verapamil uptake in frontal white matter regions compared to controls; while de novo PD patients showed lower uptake in midbrain and frontal regions. PSP and MSA patients had increased uptake in the basal ganglia. Decreased BBB P-gp function seems a late event in neurodegenerative disorders, and could enhance continuous neurodegeneration. Lower [11C]-verapamil uptake in midbrain and frontal regions of de novo PD patients could indicate a regional up-regulation of P-gp function

Systematics of c-axis Phonons in the Thallium and Bismuth Based Cuprate Superconductors

We present grazing incidence reflectivity measurements in the far infrared region at temperatures above and below Tc for a series of thallium (Tl2Ba2CuO6, Tl2Ba2CaCu2O8) and bismuth (Bi2Sr2CuO6, Bi2Sr2CaCu2O8, and Bi(2-x)Pb(x)Sr2CaCu2O8) based cuprate superconductors. From the spectra, which are dominated by the c-axis phonons, longitudinal frequencies (LO) are directly obtained. The reflectivity curves are well fitted by a series of Lorentz oscillators. In this way the transverse (TO) phonon frequencies were accurately determined. On the basis of the comparative study of the Bi and Tl based cuprates with different number of CuO2 layers per unit cell, we suggest modifications of the assignment of the main oxygen modes. We compare the LO frequencies in Bi2Sr2CaCu2O8 and Tl2Ba2Ca2Cu3O10 obtained from intrinsic Josephson junction characteristics with our measurements, and explain the discrepancy in LO frequencies obtained by the two different methods.Comment: 8 pages Revtex, 6 eps figures, 3 tables, to appear in Phys. Rev.

Parkinson's disease-related perfusion and glucose metabolic brain patterns identified with PCASL-MRI and FDG-PET imaging

AbstractIntroductionUnder normal conditions, the spatial distribution of resting cerebral blood flow and cerebral metabolic rate of glucose are closely related. A relatively new magnetic resonance (MR) technique, pseudo-continuous arterial spin labeling (PCASL), can be used to measure regional brain perfusion. We identified a Parkinson's disease (PD)-related perfusion and metabolic covariance pattern in the same patients using PCASL and FDG-PET imaging and assessed (dis)similarities in the disease-related pattern between perfusion and metabolism in PD patients.MethodsNineteen PD patients and seventeen healthy controls underwent [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging. Of 14 PD patients and all healthy controls PCASL-MRI could be obtained. Data were analyzed using scaled subprofile model/principal component analysis (SSM/PCA).ResultsUnique Parkinson's disease-related perfusion and metabolic covariance patterns were identified using PCASL and FDG-PET in the same patients. The PD-related metabolic covariance brain pattern is in high accordance with previously reports. Also our disease-related perfusion pattern is comparable to the earlier described perfusion pattern. The most marked difference between our perfusion and metabolic patterns is the larger perfusion decrease in cortical regions including the insula.ConclusionWe identified PD-related perfusion and metabolic brain patterns using PCASL and FDG-PET in the same patients which were comparable with results of existing research. In this respect, PCASL appears to be a promising addition in the early diagnosis of individual parkinsonian patients