643 research outputs found
The Pharmacopsychometric Triangle to Illustrate the Effectiveness of T-PEMF Concomitant with Antidepressants in Treatment Resistant Patients: A Double-Blind, Randomised, Sham-Controlled Trial Revisited with Focus on the Patient-Reported Outcomes
Background. Our T-PEMF trial has been revisited with focus on the pharmacopsychometric triangle in which effect size is used when comparing wanted versus unwanted clinical effects and quality of life as outcomes. In this analysis, we have especially focused on the self-reported HAM-D6. Methods. The antidepressive medication which the patients were resistant to was kept unchanged during the five weeks of active versus sham T-PEMF. Results. In total 21, patients received active T-PEMF, and 19 patients received sham T-PEMF. The effect size was 1.02 and 0.90, respectively, on HAM-D6 and HAM-D6-S. Concerning side effects, the active T-PEMF reduced the baseline score on concentration problems with an effect size of 0.44 while inducing more autonomic symptoms than sham T-PEMF with an effect size of â0.41. The advantage of active over sham T-PEMF obtained an effect size of 0.48. Conclusion. Active T-PEMF was found superior to sham T-PEMF within the pharmacopsychometric triangle with a clinically significant effect size level above 0.40
Electron-electron interaction effects in quantum point contacts
We consider electron-electron interaction effects in quantum point contacts on the first quantization plateau, taking into account all scattering processes. We compute the low-temperature linear and nonlinear conductance, shot noise, and thermopower, by perturbation theory and a self-consistent nonperturbative method. On the conductance plateau, the low-temperature corrections are solely due to momentum-nonconserving processes that change the relative number of left- and right-moving electrons. This leads to a suppression of the conductance for increasing temperature or voltage. The size of the suppression is estimated for a realistic saddle-point potential, and is largest in the beginning of the conductance plateau. For large magnetic field, interaction effects are strongly suppressed by the Pauli principle, and hence the first spin-split conductance plateau has a much weaker interaction correction. For the nonperturbative calculations, we use a self-consistent nonequilibrium Green's function approach, which suggests that the conductance saturates at elevated temperatures. These results are consistent with many experimental observations related to the so-called 0.7 anomaly
Giant bandicoot.
41 p. : ill., map ; 26 cm.
"September 14, 2010."The giant bandicoot, Peroryctes broadbenti (Ramsay, 1879), is represented in museum collections by 23 specimens collected at 12 localities in the lowlands of the southeastern peninsula (the "Papuan Peninsula") of Papua New Guinea. Available data on P. broadbenti are reviewed, including its comparative anatomy and morphological variability, taxonomic relationships, geographic and elevational distribution, dietary and reproductive traits, and conservation status. Despite previous confusion between this species and P. raffrayana (Milne-Edwards, 1878), the two species are readily distinguished by a suite of external, cranial, and dental characters. Diagnostic characters are enumerated and illustrated, and comparisons drawn with other New Guinean bandicoots. Generic distinction of Peroryctes Thomas, 1906, in cranial morphology from other New Guinean bandicoots is also reviewed. A striking degree of sexual dimorphism is documented in both body size and dentition for P. broadbenti; these comparisons are set in context by a review of sexual dimorphism among bandicoots in general
Review of Leptomys
60 p. : ill. (some col.), maps ; 26 cm.Includes bibliographical references (p. 56-60).Two new species of the endemic New Guinea rodent genus Leptomys Thomas, 1897, are described: L. paulus, indigenous to the montane forests in the Owen Stanley Range in eastern New Guinea, and L. arfakensis, known only from the Arfak Mountains on the Vogelkop Peninsula in western New Guinea. These descriptions are presented within a taxonomic review of Leptomys based on all known specimens in collections of the world's museums. In addition to the new species, the morphological attributes and geographic distributions of three others are documented. Leptomys elegans occurs in southcentral and southeastern New Guinea both north and south of the Central Cordillera, ranging from the Kikori River Basin in the west to the southern slopes of the Owen Stanley Range, then extending round to the north side of the Cordillera in the Maneau Range, and in the outlying highland block of Mount Victory. Leptomys signatus is recorded only from the Fly and Kikori River drainages south of the Central Cordillera. Leptomys ernstmayri is found in montane forests of the eastern Central Cordillera (Aroa River to Mt. Karimui), reaches to the outlying mountains on the Huon Peninsula and the Adelbert Range, and also occurs in the isolated Foja Mountains of far western New Guinea. Judged by variation in qualitative and morphometric external, cranial, and dental traits associated with available samples, L. arfakensis, n. sp., is likely more closely related to L. elegans and L. signatus, all with large bodies and relatively short tails, than to L. ernstmayri and L. paulus, n. sp., that are characterized, among other features, by smaller body size and relatively longer tails. There is significant phenetic divergence among the geographic samples identified here as L. ernstmayri, and additional inquiry, especially utilizing data from molecular sources, is required to determine whether this intersample variation reflects the presence of separate species, each endemic to the Huon Peninsula, Adelbert Range, Central Cordillera, and possibly the Foja Mountains, or instead represents montane variation within a single morphologically variable species
Intershell resistance in multiwall carbon nanotubes: A Coulomb drag study
We calculate the intershell resistance R_{21} in a multiwall carbon nanotube
as a function of temperature T and Fermi level (e.g. a gate voltage), varying
the chirality of the inner and outer tubes. This is done in a so-called Coulomb
drag setup, where a current I_1 in one shell induces a voltage drop V_2 in
another shell by the screened Coulomb interaction between the shells neglecting
the intershell tunnelling. We provide benchmark results for R_{21}=V_2/I_1
within the Fermi liquid theory using Boltzmann equations. The band structure
gives rise to strongly chirality dependent suppression effects for the Coulomb
drag between different tubes due to selection rules combined with mismatching
of wave vector and crystal angular momentum conservation near the Fermi level.
This gives rise to orders of magnitude changes in R_{21} and even the sign of
R_{21} can change depending on the chirality of the inner and outer tube and
misalignment of inner and outer tube Fermi levels. However for any tube
combination, we predict a dip (or peak) in R_{21} as a function of gate
voltage, since R_{21} vanishes at the electron-hole symmetry point. As a
byproduct, we classified all metallic tubes into either zigzag-like or
armchair-like, which have two different non-zero crystal angular momenta m_a,
m_b and only zero angular momentum, respectively.Comment: 17 pages, 10 figure
ThermoElectric Transport Properties of a Chain of Quantum Dots with Self-Consistent Reservoirs
We introduce a model for charge and heat transport based on the
Landauer-Buttiker scattering approach. The system consists of a chain of
quantum dots, each of them being coupled to a particle reservoir. Additionally,
the left and right ends of the chain are coupled to two particle reservoirs.
All these reservoirs are independent and can be described by any of the
standard physical distributions: Maxwell-Boltzmann, Fermi-Dirac and
Bose-Einstein. In the linear response regime, and under some assumptions, we
first describe the general transport properties of the system. Then we impose
the self-consistency condition, i.e. we fix the boundary values (T_L,\mu_L) and
(T_R,mu_R), and adjust the parameters (T_i,mu_i), for i = 1,...,N, so that the
net average electric and heat currents into all the intermediate reservoirs
vanish. This condition leads to expressions for the temperature and chemical
potential profiles along the system, which turn out to be independent of the
distribution describing the reservoirs. We also determine the average electric
and heat currents flowing through the system and present some numerical
results, using random matrix theory, showing that these currents are typically
governed by Ohm and Fourier laws.Comment: Minor changes (45 pages
Electronic transport in inhomogeneous quantum wires
We study the transport properties of a long non-uniform quantum wire where
the electron-electron interactions and the density vary smoothly at large
length scales. We show that these inhomogeneities lead to a finite resistivity
of the wire, due to a weak violation of momentum conservation in the collisions
between electrons. Estimating the rate of change of momentum associated with
non-momentum-conserving scattering processes, we derive the expression for the
resistivity of the wire in the regime of weakly interacting electrons and find
a contribution linear in temperature for a broad range of temperatures below
the Fermi energy. By estimating the energy dissipated throughout the wire by
low-energy excitations, we then develop a different method for deriving the
resistivity of the wire, which can be combined with the bosonization formalism.
This allows us to compare our results with previous works relying on an
extension of the Tomonaga-Luttinger model to inhomogeneous systems.Comment: 18 pages, 2 figures. Invited paper for special issue of Journal of
Physics: Condensed Matter on "The 0.7 Feature and Interactions in
One-dimensional Systems
Three-particle collisions in quantum wires: Corrections to thermopower and conductance
We consider the effect of electron-electron interaction on the electron
transport through a finite length single-mode quantum wire with reflectionless
contacts. The two-particle scattering events cannot alter the electric current
and therefore we study the effect of three-particle collisions. Within the
Boltzmann equation framework, we calculate corrections to the thermopower and
conductance to the leading order in the interaction and in the length of wire
. We check explicitly that the three-particle collision rate is identically
zero in the case of several integrable interaction potentials. In the general
(non-integrable) case, we find a positive contribution to the thermopower to
leading order in . The processes giving rise to the correction involve
electron states deep in the Fermi sea. Therefore the correction follows an
activation law with the characteristic energy of the order of the Fermi energy
for the electrons in the wire.Comment: 13 pages, 4 figure
The merit of high-frequency data in portfolio allocation
This paper addresses the open debate about the usefulness of high-frequency (HF) data in large-scale portfolio allocation. Daily covariances are estimated based on HF data of the S&P 500 universe employing a blocked realized kernel estimator. We propose forecasting covariance matrices using a multi-scale spectral decomposition where volatilities, correlation eigenvalues and eigenvectors evolve on different frequencies. In an extensive out-of-sample forecasting study, we show that the proposed approach yields less risky and more diversified portfolio allocations as prevailing methods employing daily data. These performance gains hold over longer horizons than previous studies have shown
The role of healthcare professionals in encouraging parents to see and hold their stillborn baby: a meta-synthesis of qualitative studies.
Background: Globally, during 2013 there were three million recorded stillbirths. Where clinical guidelines exist some recommend that professionals do not encourage parental contact. The guidance is based on quantitative evidence that seeing and holding the baby is not beneficial for everyone, but has been challenged by bereaved parents' organisations. We aim to inform future guideline development through a synthesis of qualitative studies reporting data relevant to the research question; how does the approach of healthcare professionals to seeing and holding the baby following stillbirth impact parents views and experiences?
Methods/Findings: Using a predetermined search strategy of PubMed and PsychINFO we identified robust qualitative studies reporting bereaved parental views and/or experiences relating to seeing and holding their stillborn baby (final search 24 February, 2014). Eligible studies were English language, reporting parental views, with gestational loss >20weeks. Quality was independently assessed by three authors using a validated tool. We used meta-ethnographic techniques to identify key themes and a line of argument synthesis. We included 12 papers, representing the views of 333 parents (156 mothers, 150 fathers, and 27 couples) from six countries. The final themes were: "[Still]birth: Nature of care is paramount", "Real babies: Perfect beauties, monsters and spectres", and "Opportunity of a lifetime lost." Our line-of-argument synthesis highlights the contrast between all parents need to know their baby, with the time around birth being the only time memories can be made, and the variable ability that parents have to articulate their preferences at that time. Thus, we hypothesised that how health professionals approach contact between parents and their stillborn baby demands a degree of active management. An important limitation of this paper is all included studies originated from high income, westernised countries raising questions about the findings transferability to other cultural contexts. We do not offer new evidence to answer the question "Should parents see and hold their stillborn baby?", instead our findings advance understanding of how professionals can support parents to make appropriate decisions in a novel, highly charged and dynamic situation.
Conclusions: Guidelines could be more specific in their recommendations regarding parental contact. The role of healthcare professionals in encouraging parents to see and hold their stillborn baby is paramount. Parental choice not to see their baby, apprehension, or uncertainty should be continuously revisited in the hours after birth as the opportunity for contact is fleeting and final
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