443 research outputs found
Striatal dopamine D2 receptor binding of risperidone in schizophrenic patients as assessed by 123I-iodobenzamide SPECT: a comparative study with olanzapine
The aim of this investigation was to compare the degree of striatal dopamine-(D2) receptor blockade by two atypical antipsychotic drugs, risperidone and olanzapine. The percentage of D2 receptor occupancy during treatment was calculated by comparing the results of 123I-iodobenzamide SPECT with those from healthy control subjects. Twenty inpatients suffering from schizophrenia or schizoaffective psychosis according to DSM IV/ICD-10 criteria were treated with clinically recommended doses of risperidone and compared with 13 inpatients treated with up to 20 mg olanzapine. Neuroleptic dose and D2 receptor blockade correlated strongly for both risperidone (Pearson r = –0.86, p = 0.0001) and olanzapine (Pearson r = –0.77, p = 0.002). There was no significant difference between the D2 receptor occupancy of the two substances when given in the clinically recommended dose range (unpaired t-test, t= –0.112, p=0.911)
Cosmic Swarms: A search for Supermassive Black Holes in the LISA data stream with a Hybrid Evolutionary Algorithm
We describe a hybrid evolutionary algorithm that can simultaneously search
for multiple supermassive black hole binary (SMBHB) inspirals in LISA data. The
algorithm mixes evolutionary computation, Metropolis-Hastings methods and
Nested Sampling. The inspiral of SMBHBs presents an interesting problem for
gravitational wave data analysis since, due to the LISA response function, the
sources have a bi-modal sky solution. We show here that it is possible not only
to detect multiple SMBHBs in the data stream, but also to investigate
simultaneously all the various modes of the global solution. In all cases, the
algorithm returns parameter determinations within (as estimated from
the Fisher Matrix) of the true answer, for both the actual and antipodal sky
solutions.Comment: submitted to Classical & Quantum Gravity. 19 pages, 4 figure
Rotating Nuclear Rings and Extreme Starbursts in Ultraluminous Galaxies
New high resolution interferometer data of 10 IR ultraluminous galaxies shows
the molecular gas is in rotating nuclear rings or disks with radii 300 to 800
pc. Most of the CO flux comes from a moderate-density, warm, intercloud medium
rather than self-gravitating clouds. Gas masses of ~ 5 x 10^9 Msun, 5 times
lower than the standard method are derived from a model of the molecular disks.
The ratio of molecular gas to dynamical mass, is M_gas/M_dyn ~ 1/6 with a
maximum ratio of gas to total mass surface density of 1/3. For the galaxies
VIIZw31, Arp193, and IRAS 10565+24, there is good evidence for rotating
molecular rings with a central gap. In addition to the rotating rings a new
class of star formation region is identified which we call an Extreme
Starburst. They have a characteristic size of only 100 pc., about 10^9 Msun of
gas and an IR luminosity of ~3 x 10^11 Lsun. Four extreme starbursts are
identified in the 3 closest galaxies in the sample Arp220, Arp193 and Mrk273.
They are the most prodigious star formation events in the local universe, each
representing about 1000 times as many OB stars as 30 Doradus. In Arp220, the CO
and 1.3 mm continuum maps show the two ``nuclei'' embedded in a central ring or
disk and a fainter structure extending 3 kpc to the east, normal to the nuclear
disk. There is no evidence that these sources really are the pre-merger nuclei.
They are compact, extreme starburst regions containing 10^9 Msun of dense
molecular gas and new stars, but no old stars. Most of the dust emission and
HCN emission arises in the two extreme starbursts. The entire bolometric
luminosity of Arp~220 comes from starbursts, not an AGN. In Mrk231, the disk
geometry shows that the molecular disk cannot be heated by the AGN; the far IR
luminosity of Mrk~231 is powered by a starburst, not the AGN. (Abridged)Comment: 97 pages Latex with aasms.sty, including 29 encapsulated Postscript
figures. Figs 18 and 23 are GIFs. 31 figures total. Text and higher quality
versions of figures available at
http://sbastk.ess.sunysb.edu/www/RINGS_ESB_PREPRINT.html To be published in
Ap. J., 10 Nov. 199
Stripes, Pseudogaps, and Van Hove Nesting in the Three-band tJ Model
Slave boson calculations have been carried out in the three-band tJ model for
the high-T_c cuprates, with the inclusion of coupling to oxygen breathing mode
phonons. Phonon-induced Van Hove nesting leads to a phase separation between a
hole-doped domain and a (magnetic) domain near half filling, with long-range
Coulomb forces limiting the separation to a nanoscopic scale. Strong
correlation effects pin the Fermi level close to, but not precisely at the Van
Hove singularity (VHS), which can enhance the tendency to phase separation. The
resulting dispersions have been calculated, both in the uniform phases and in
the phase separated regime. In the latter case, distinctly different
dispersions are found for large, random domains and for regular (static)
striped arrays, and a hypothetical form is presented for dynamic striped
arrays. The doping dependence of the latter is found to provide an excellent
description of photoemission and thermodynamic experiments on pseudogap
formation in underdoped cuprates. In particular, the multiplicity of observed
gaps is explained as a combination of flux phase plus charge density wave (CDW)
gaps along with a superconducting gap. The largest gap is associated with VHS
nesting. The apparent smooth evolution of this gap with doping masks a
crossover from CDW-like effects near optimal doping to magnetic effects (flux
phase) near half filling. A crossover from large Fermi surface to hole pockets
with increased underdoping is found. In the weakly overdoped regime, the CDW
undergoes a quantum phase transition (), which could be obscured
by phase separation.Comment: 15 pages, Latex, 18 PS figures Corrects a sign error: major changes,
esp. in Sect. 3, Figs 1-4,6 replace
Shared Genetic Etiology Between Alcohol Dependence and Major Depressive Disorder
The clinical comorbidity of alcohol dependence (AD) and
major depressive disorder (MDD) is well established,
whereas genetic factors influencing co-occurrence remain
unclear. A recent study using polygenic risk scores (PRS)
calculated based on the first-wave Psychiatric Genomics
Consortium MDD meta-analysis (PGC-MDD1) suggests a
modest shared genetic contribution to MDD and AD. Using a
(∼10 fold) larger discovery sample, we calculated PRS
based on the second wave (PGC-MDD2) of results, in a
severe AD case–control target sample. We found significant associations between AD disease status and MDD-PRS derived from both PGC-MDD2 (most informative
P-threshold=1.0, P=0.00063, R2=0.533%) and PGCMDD1
(P-threshold=0.2, P=0.00014, R2=0.663%) metaanalyses;
the larger discovery sample did not yield
additional predictive power. In contrast, calculating PRS in a MDD target sample yielded increased power when using
PGC-MDD2 (P-threshold=1.0, P=0.000038, R2=1.34%)
versus PGC-MDD1 (P-threshold=1.0, P=0.0013,
R2=0.81%). Furthermore, when calculating PGC-MDD2
PRS in a subsample of patients with AD recruited explicitly excluding comorbid MDD, significant associations were still found (n=331; P-threshold=1.0, P=0.042, R2=0.398%). Meanwhile, in the subset of patients in which MDD was not the explicit exclusion criteria, PRS predicted more variance (n=999; P-threshold=1.0, P=0.0003, R2=0.693%). Our findings replicate the reported genetic overlap between AD and MDD and also suggest the need for improved, rigorous phenotyping to identify true shared cross-disorder genetic factors. Larger target samples are needed to reduce noise and take advantage of increasing discovery sample size
Human Auditory Cortical Activation during Self-Vocalization
During speaking, auditory feedback is used to adjust vocalizations. The brain systems mediating this integrative ability have been investigated using a wide range of experimental strategies. In this report we examined how vocalization alters speech-sound processing within auditory cortex by directly recording evoked responses to vocalizations and playback stimuli using intracranial electrodes implanted in neurosurgery patients. Several new findings resulted from these high-resolution invasive recordings in human subjects. Suppressive effects of vocalization were found to occur only within circumscribed areas of auditory cortex. In addition, at a smaller number of sites, the opposite pattern was seen; cortical responses were enhanced during vocalization. This increase in activity was reflected in high gamma power changes, but was not evident in the averaged evoked potential waveforms. These new findings support forward models for vocal control in which efference copies of premotor cortex activity modulate sub-regions of auditory cortex
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Remarks on the Concept of Critique in Habermasian Thought
The main purpose of this paper is to examine the concept of critique in Habermasian thought. Given that the concept of critique is a central theoretical category in the work of the Frankfurt School, it comes as a surprise that little in the way of a systematic account which sheds light on the multifaceted meanings of the concept of critique in Habermas’s oeuvre can be found in the literature. This paper aims to fill this gap by exploring the various meanings that Habermas attributes to the concept of critique in 10 key thematic areas of his writings: (1) the public sphere, (2) knowledge, (3) language, (4) morality, (5) ethics, (6) evolution, (7) legitimation, (8) democracy, (9) religion, and (10) modernity. On the basis of a detailed analysis of Habermas’s multifaceted concerns with the nature and function of critique, the study seeks to demonstrate that the concept of critique can be considered not only as a constitutive element but also as a normative cornerstone of Habermasian thought. The paper draws to a close by reflecting on some of the limitations of Habermas’s conception of critique, arguing that in order to be truly critical in the Habermasian sense we need to turn the subject of critique into an object of critique
Big data-driven fuzzy cognitive map for prioritising IT service procurement in the public sector
YesThe prevalence of big data is starting to spread across the public and private sectors however, an impediment to its widespread adoption orientates around a lack of appropriate big data analytics (BDA) and resulting skills to exploit the full potential of big data availability. In this paper, we propose a novel BDA to contribute towards this void, using a fuzzy cognitive map (FCM) approach that will enhance decision-making thus prioritising IT service procurement in the public sector. This is achieved through the development of decision models that capture the strengths of both data analytics and the established intuitive qualitative approach. By taking advantages of both data analytics and FCM, the proposed approach captures the strength of data-driven decision-making and intuitive model-driven decision modelling. This approach is then validated through a decision-making case regarding IT service procurement in public sector, which is the fundamental step of IT infrastructure supply for publics in a regional government in the Russia federation. The analysis result for the given decision-making problem is then evaluated by decision makers and e-government expertise to confirm the applicability of the proposed BDA. In doing so, demonstrating the value of this approach in contributing towards robust public decision-making regarding IT service procurement.EU FP7 project Policy Compass (Project No. 612133
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