170 research outputs found
Nefazodone in psychotic unipolar and bipolar depression: A retrospective chart analysis and open prospective study on its efficacy and safety versus combined treatment with amitriptyline and haloperidol
Although atypical antipsychotics are on the rise, traditional treatment of psychotic (or delusional) depression mostly includes the addition of classical antipsychotics to antidepressants. As there are only few data supporting this approach compared with antidepressant monotherapy, and almost no data comparing it with antidepressants of the latest generation, we conducted a retrospective chart analysis and a prospective, randomized open study on the efficacy and tolerability of nefazodone monotherapy versus combined treatment with amitriptyline and haloperidol in psychotic depression. The results suggest that the addition of classical antipsychotics should be reserved for those with very severe psychotic symptoms, but may not be needed in milder forms. Copyright (c) 2003 S. Karger AG, Basel
Strong-field spatial interference in a tailored electromagnetic bath
Light scattered by a regular structure of atoms can exhibit interference
signatures, similar to the classical double-slit. These first-order
interferences, however, vanish for strong light intensities, restricting
potential applications. Here, we show how to overcome these limitations to
quantum interference in strong fields. First, we recover the first-order
interference in strong fields via a tailored electromagnetic bath with a
suitable frequency dependence. At strong driving, the optical properties for
different spectral bands are distinct, thus extending the set of observables.
We further show that for a two-photon detector as, e.g., in lithography,
increasing the field intensity leads to twice the spatial resolution of the
second-order interference pattern compared to the weak-field case.Comment: final versio
Is the Atlantic subpolar gyre bistable in comprehensive coupled climate models?
The Atlantic subpolar gyre (SPG) is one of the main drivers of decadal climate variability in the North Atlantic. Here we analyze its dynamics in pre-industrial control simulations of 19 different comprehensive coupled climate models. The analysis is based on a recently proposed description of the SPG dynamics that found the circulation to be potentially bistable due to a positive feedback mechanism including salt transport and enhanced deep convection in the SPG center. We employ a statistical method to identify multiple equilibria in time series that are subject to strong noise and analyze composite fields to assess whether the bistability results from the hypothesized feedback mechanism. Because noise dominates the time series in most models, multiple circulation modes can unambiguously be detected in only six models. Four of these six models confirm that the intensification is caused by the positive feedback mechanis
Quantum storage of polarization qubits in birefringent and anisotropically absorbing materials
Storage of quantum information encoded into true single photons is an
essential constituent of long-distance quantum communication based on quantum
repeaters and of optical quantum information processing. The storage of
photonic polarization qubits is, however, complicated by the fact that many
materials are birefringent and have polarization-dependent absorption. Here we
present and demonstrate a simple scheme that allows compensating for these
polarization effects. The scheme is demonstrated using a solid-state quantum
memory implemented with an ensemble of rare-earth ions doped into a biaxial
yttrium orthosilicate () crystal. Heralded single photons generated
from a filtered spontaneous parametric downconversion source are stored, and
quantum state tomography of the retrieved polarization state reveals an average
fidelity of , which is significantly higher than what is
achievable with a measure-and-prepare strategy.Comment: 7 pages, 3 figures, 1 table, corrected typos and added ref. 3
DNA methylation analysis of the angiotensin converting enzyme (ACE) gene in major depression.
The angiotensin converting enzyme (ACE) has been repeatedly discussed as susceptibility factor for major depression (MD) and the bi-directional relation between MD and cardiovascular disorders (CVD). In this context, functional polymorphisms of the ACE gene have been linked to depression, to antidepressant treatment response, to ACE serum concentrations, as well as to hypertension, myocardial infarction and CVD risk markers. The mostly investigated ACE Ins/Del polymorphism accounts for ~40%-50% of the ACE serum concentration variance, the remaining half is probably determined by other genetic, environmental or epigenetic factors, but these are poorly understood.
The main aim of the present study was the analysis of the DNA methylation pattern in the regulatory region of the ACE gene in peripheral leukocytes of 81 MD patients and 81 healthy controls.
We detected intensive DNA methylation within a recently described, functional important region of the ACE gene promoter including hypermethylation in depressed patients (p = 0.008) and a significant inverse correlation between the ACE serum concentration and ACE promoter methylation frequency in the total sample (p = 0.02). Furthermore, a significant inverse correlation between the concentrations of the inflammatory CVD risk markers ICAM-1, E-selectin and P-selectin and the degree of ACE promoter methylation in MD patients could be demonstrated (p = 0.01 - 0.04).
The results of the present study suggest that aberrations in ACE promoter DNA methylation may be an underlying cause of MD and probably a common pathogenic factor for the bi-directional relationship between MD and cardiovascular disorders
Saving time and money: a validation of the self ratings on the prospective NIMH life-chart method (NIMH-LCM)
Background: Careful observation of the longitudinal course of bipolar disorders is pivotal to finding optimal treatments and improving outcome. A useful tool is the daily prospective Life-Chart Method, developed by the National Institute of Mental Health. However, it remains unclear whether the patient version is as valid as the clinician version. Methods: We compared the patient-rated version of the Lifechart (LC-self) with the Young-Mania-Rating Scale (YMRS), Inventory of Depressive Symptoms-Clinician version (IDS-C), and Clinical Global Impression-Bipolar version (CGI-BP) in 108 bipolar I and II patients who participated in the Naturalistic Follow-up Study (NFS) of the German centres of the Bipolar Collaborative Network (BCN; formerly Stanley Foundation Bipolar Network). For statistical evaluation, levels of severity of mood states on the Lifechart were transformed numerically and comparison with affective scales was performed using chi-square and t tests. For testing correlations Pearson's coefficient was calculated. Results: Ratings for depression of LC-self and total scores of IDS-C were found to be highly correlated (Pearson coefficient r = -.718; p < .001), whilst the correlation of ratings for mania with YMRS compared to LC-self were slightly less robust (Pearson coefficient r = .491; p = .001). These results were confirmed by good correlations between the CGI-BP IA (mania), IB (depression) and IC (overall mood state) and the LC-self ratings (Pearson coefficient r = .488, r = .721 and r = .65, respectively; all p < .001). Conclusions: The LC-self shows a significant correlation and good concordance with standard cross sectional affective rating scales, suggesting that the LC-self is a valid and time and money saving alternative to the clinician-rated version which should be incorporated in future clinical research in bipolar disorder. Generalizability of the results is limited by the selection of highly motivated patients in specialized bipolar centres and by the open design of the study
Warm Greenland during the last interglacial: the role of regional changes in sea ice cover
The last interglacial, also known as the Eemian, is characterized by warmer
than present conditions at high latitudes. This is implied by various Eemian
proxy records as well as by climate model simulations, though the models
mostly underestimate the warming with respect to proxies. Simulations of
Eemian surface air temperatures (SAT) in the Northern Hemisphere extratropics
further show large variations between different climate models, and it has
been hypothesized that this model spread relates to diverse representations
of the Eemian sea ice cover. Here we use versions 3 and 4 of the Community
Climate System Model (CCSM3 and CCSM4) to highlight the crucial role of sea
ice and sea surface temperatures changes for the Eemian climate, in
particular in the North Atlantic sector and in Greenland. A substantial
reduction in sea ice cover results in an amplified atmospheric warming and
thus a better agreement with Eemian proxy records. Sensitivity experiments
with idealized lower boundary conditions reveal that warming over Greenland
is mostly due to a sea ice retreat in the Nordic Seas. In contrast, sea ice
changes in the Labrador Sea have a limited local impact. Changes in sea ice
cover in either region are transferred to the overlying atmosphere through
anomalous surface energy fluxes. The large-scale spread of the warming
resulting from a Nordic Seas sea ice retreat is mostly explained by anomalous
heat advection rather than by radiation or condensation processes. In
addition, the sea ice perturbations lead to changes in the hydrological
cycle. Our results consequently imply that both temperature and snow
accumulation records from Greenland ice cores are sensitive to sea ice
changes in the Nordic Seas but insensitive to sea ice changes in the Labrador
Sea. Moreover, the simulations suggest that the uncertainty in the Eemian sea
ice cover accounts for 1.6 °C of the Eemian warming at the NEEM ice
core site. The estimated Eemian warming of 5 °C above present day
based on the NEEM δ15N record can be reconstructed by the CCSM4
model for the scenario of a substantial sea ice retreat in the Nordic Seas
combined with a reduced Greenland ice sheet
Application-oriented Method for Determining the Adhesion between Insulated Flat Copper Wire and Impregnation Resin
In the field of hairpin stator technology, increasing demands are currently being made on the semi-finished product of insulated flat copper wire. In particular, the focus is on the electrical requirements against the background of increasing voltage levels to 800 V and more. The test procedures described in the standards IEC 60317 & 60851 for verifying the properties of insulated flat copper wires only partially map the requirements from the point of automotive industry. An example for insufficiently considered properties lays in the correlation between wire and insulation resin. In addition to electrical and thermal benefits, impregnation helps to mechanically stabilize the winding and protect it from ambient factors. Adhesion between the winding and the impregnating resin is a key parameter here, but is not considered in material pre-selection today. The adhesion of the impregnation resin to the insulated wire is essential to ensure the lifetime of electric motors. This paper describes a method for determining the adhesion of the impregnating resin to the insulation of the wire. It could be shown that there is a correlation between the material of the wire insulation and the impregnating resin in terms of adhesion. Further on the described method can be used for an application-oriented specification of insulated copper flat wires to ensure a consistent composition of the insulation material
Dependence of Eemian Greenland temperature reconstructions on the ice sheet topography
The influence of a reduced Greenland Ice Sheet (GrIS) on Greenland's surface climate during the Eemian interglacial is studied using a set of simulations with different GrIS realizations performed with a comprehensive climate model. We find a distinct impact of changes in the GrIS topography on Greenland's surface air temperatures (SAT) even when correcting for changes in surface elevation, which influences SAT through the lapse rate effect. The resulting lapse-rate-corrected SAT anomalies are thermodynamically driven by changes in the local surface energy balance rather than dynamically caused through anomalous advection of warm/cold air masses. The large-scale circulation is indeed very stable among all sensitivity experiments and the Northern Hemisphere (NH) flow pattern does not depend on Greenland's topography in the Eemian. In contrast, Greenland's surface energy balance is clearly influenced by changes in the GrIS topography and this impact is seasonally diverse. In winter, the variable reacting strongest to changes in the topography is the sensible heat flux (SHF). The reason is its dependence on surface winds, which themselves are controlled to a large extent by the shape of the GrIS. Hence, regions where a receding GrIS causes higher surface wind velocities also experience anomalous warming through SHF. Vice-versa, regions that become flat and ice-free are characterized by low wind speeds, low SHF, and anomalous low winter temperatures. In summer, we find surface warming induced by a decrease in surface albedo in deglaciated areas and regions which experience surface melting. The Eemian temperature records derived from Greenland proxies, thus, likely include a temperature signal arising from changes in the GrIS topography. For the Eemian ice found in the NEEM core, our model suggests that up to 3.1 °C of the annual mean Eemian warming can be attributed to these topography-related processes and hence is not necessarily linked to large-scale climate variations
Atomistic-to-continuum coupling
Atomistic-to-continuum (a/c) coupling methods are a class of computational multiscale schemes that combine the accuracy of atomistic models with the efficiency of continuum elasticity. They are increasingly being utilized in materials science to study the fundamental mechanisms of material failure such as crack propagation and plasticity, which are governed by the interaction between crystal defects and long-range elastic fields.
In the construction of a/c coupling methods, various approximation errors are committed. A rigorous numerical analysis approach that classifies and quantifies these errors can give confidence in the simulation results, as well as enable optimization of the numerical methods for accuracy and computational cost. In this article, we present such a numerical analysis framework, which is inspired by recent research activity
- …