24,385 research outputs found
Herschel-PACS imaging of protostars in the HH 1–2 outflow complex
We present 70 and 160 μm Herschel science demonstration images of a field in the Orion A molecular cloud that contains the prototypical Herbig-Haro objects HH 1 and 2, obtained with the Photodetector Array Camera and Spectrometer (PACS). These observations demonstrate Herschel’s unprecedented ability to study the rich population of protostars in the Orion molecular clouds
at the wavelengths where they emit most of their luminosity. The four protostars previously identified by Spitzer 3.6–40 μm imaging and spectroscopy are detected in the 70 μm band, and three are clearly detected at 160 μm. We measure photometry of the protostars in the PACS bands and assemble their spectral energy distributions (SEDs) from 1 to 870 μm with these data, Spitzer spectra and
photometry, 2MASS data, and APEX sub-mm data. The SEDs are fit to models generated with radiative transfer codes. From these fits we can constrain the fundamental properties of the protostars. We find luminosities in the range 12–84 L_⊙ and envelope densities spanning over two orders of magnitude. This implies that the four protostars have a wide range of envelope infall rates and evolutionary
states: two have dense, infalling envelopes, while the other two have only residual envelopes. We also show the highly irregular and filamentary structure of the cold dust and gas surrounding the protostars as traced at 160 μm
Teaching percutaneous renal biopsy using unfixed human cadavers
Background:
Percutaneous renal biopsy (PRB) is an important diagnostic procedure. Despite advances in its safety profile there remains a small but significant risk of bleeding complications. Traditionally, operators train to perform PRB through tutor instruction and directly supervised PRB attempts on real patients. We describe an approach to teaching operators to perform PRB using cadaveric simulation.
Methods:
We devised a full day course hosted in the Clinical Anatomy Skills Centre, with places for nine candidates. Course faculty consisted of two Consultant Nephrologists, two Nephrology trainees experienced in PRB, and one Radiologist.
Classroom instruction included discussion of PRB indications, risk minimisation, and management of complications. Two faculty members acted as models for the demonstration of kidney localisation using real-time ultrasound scanning. PRB was demonstrated using a cadaveric model, and candidates then practised PRB using each cadaver model.
Results:
Written candidate feedback was universally positive. Faculty considered the cadaveric model a realistic representation of live patients, while the use of multiple cadavers introduced anatomical variation.
Conclusions:
Our model facilitates safe simulation of a high risk procedure. This might reduce serious harm associated with PRB and improve patient safety, benefiting trainee operators and patients alike
General Lower Bounds for b -> d Penguin Processes
For the exploration of flavour physics, b -> d penguin processes are an
important aspect, with the prominent example of \bar B^0_d -> K^0 \bar K^0. We
recently derived lower bounds for the CP-averaged branching ratio of this
channel in the Standard Model; they were found to be very close to the
corresponding experimental upper limits, thereby suggesting that \bar B^0_d ->
K^0 \bar K^0 should soon be observed. In fact, the BaBar collaboration
subsequently announced the first signals of this transition. Here we point out
that it is also possible to derive lower bounds for \bar B -> \rho \gamma
decays, which are again surprisingly close to the current experimental upper
limits. We show that these bounds are realizations of a general bound that
holds within the Standard Model for b -> d penguin processes, allowing further
applications to decays of the kind B^\pm -> K^{(\ast)\pm} K^{(\ast)} and B^\pm
-> \pi^\pm \ell^+ \ell^-, \rho^\pm \ell^+ \ell^-.Comment: Minor changes, to appear as rapid communication in Phys. Rev
Optical nanolithography using a scanning near-field probe with an integrated light source
An ultracompact near-field optical probe is described that is based on a single, integrated assembly consisting of a gallium nitride (GaN) light-emitting diode (LED), a microlens, and a cantilever assembly containing a hollow pyramidal probe with a subwavelength aperture at its apex. The LED emits ultraviolet light and may be used as a light source for near-field photolithographic exposure. Using this simple device compatible with many commercial atomic force microscope systems, it is possible to form nanostructures in photoresist with a resolution of 35 nm, corresponding to λ/10. © 2008 American Institute of Physics
Comparative efficacy of escitalopram in the treatment of major depressive disorder
Mazen K Ali, Raymond W LamDepartment of Psychiatry, University of British Columbia, and Mood Disorders Centre, University of British Columbia Hospital, Vancouver, CanadaBackground: Escitalopram is an allosteric selective serotonin reuptake inhibitor (SSRI) with some indication of superior efficacy in the treatment of major depressive disorder. In this systematic review, we critically evaluate the evidence for comparative efficacy and tolerability of escitalopram, focusing on pooled and meta-analysis studies.Methods: A literature search was conducted for escitalopram studies that quantitatively synthesized data from comparative randomized controlled trials in MDD. Studies were excluded if they did not focus on efficacy, involved primarily subgroups of patients, or synthesized data included in subsequent studies. Outcomes extracted from the included studies were weighted mean difference or standard mean difference, response and remission rates, and withdrawal rate owing to adverse events.Results: The search initially identified 24 eligible studies, of which 12 (six pooled analysis and six meta-analysis studies) met the criteria for review. The pooled and meta-analysis studies with citalopram showed significant but modest differences in favor of escitalopram, with weighted mean differences ranging from 1.13 to 1.73 points on the Montgomery Asberg Depression Rating Scale, response rate differences of 7.0%–8.3%, and remission rate differences of 5.1%–17.6%. Pooled analysis studies showed efficacy differences compared with duloxetine and with serotonin noradrenaline reuptake inhibitors combined, but meta-analysis studies did not. The effect sizes of the efficacy differences increased in the severely depressed patient subgroups.Conclusion: Based on pooled and meta-analysis studies, escitalopram demonstrates superior efficacy compared with citalopram and with SSRIs combined. Escitalopram shows similar efficacy to serotonin noradrenaline reuptake inhibitors but the number of trials in these comparisons is limited. Efficacy differences are modest but clinically relevant, especially in more severely depressed patients.Keywords: escitalopram, depressive disorders, meta-analysis, pooled analysis, efficacy, antidepressant
The impact of reservoir conditions on the residual trapping of carbon dioxide in Berea sandstone
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Method of identifying inhibitors of glutathione S-transferase (GST) gene expression
Complementary DNA and genomic clones for three variants of GST-.pi. are disclosed. It is demonstrated that certain of these variants are overexpressed in gliomas, thereby indicating an involvement with that form of cancer. This permits the detection and treatment of certain classes of tumors using new compositions such as GST-.pi. genes, oligonucleotides, peptides and antibodies.Board of Regents, University of Texas Syste
Simple generalizations of Anti-de Sitter space-time
We consider new cosmological solutions which generalize the cosmological
patch of the Anti-de Sitter (AdS) space-time, allowing for fluids with
equations of state such that . We use them to derive the associated
full manifolds. We find that these solutions can all be embedded in flat
five-dimensional space-time with signature, revealing deformed
hyperboloids. The topology and causal-structure of these spaces is therefore
unchanged, and closed time-like curves are identified, before a covering space
is considered. However the structure of Killing vector fields is entirely
different and so we may expect a different structure of Killing horizons in
these solutions.Comment: 6 Pages, 5 Figures, Corrections and additions made for publication in
Journal of Classical and Quantum Gravit
Erratum to “Regularity theory for time-fractional advection-diffusion-reaction equations” [Comput. Math. Appl. 79 (2020) 947–961] (Computers and Mathematics with Applications (2020) 79(4) (947–961), (S0898122119304055), (10.1016/j.camwa.2019.08.008))
In this note, we correct the statement of Theorem 12 from the paper in the title above (McLean et al., 2020) and fill some gaps in the proof
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