638 research outputs found
Risk evaluation with enhaced covariance matrix
We propose a route for the evaluation of risk based on a transformation of
the covariance matrix. The approach uses a `potential' or `objective' function.
This allows us to rescale data from different assets (or sources) such that
each data set then has similar statistical properties in terms of their
probability distributions. The method is tested using historical data from both
the New York and Warsaw Stock Exchanges.Comment: see urbanowicz.org.p
Triage of women with equivocal or low-grade cervical cytology results: a meta-analysis of the HPV test positivity rate
Introduction Methods Results Discussion Conclusion Abstract Consistent evidence underlines the utility of human papillomavirus (HPV) DNA testing in the management of women with equivocal cervical cytological abnormalities, but not in case of low-grade lesions. We performed a meta-analysis including studies where the high-risk probe of the Hybrid Capture-II is used to triage these two cytological categories. The triage test-positivity rate reflects the colposcopy referral workload.Data were pooled on the HPV test positivity rate in women with atypical squamous cells of undetermined significance (ASCUS/ASC-US) or low-grade squamous intraepithelial lesions (LSIL), derived from different cytological classification systems. The meta-analysis was restricted to studies, published between 1991 and 2007. A random-effect model was applied for meta-analytical pooling and the influence of covariates on the HPV positivity rate was analyzed by meta-regression. The variation by age was assessed within individual studies since age strata were not defined uniformly. On an average, 43% (95% CI: 40-46%) of women with ASCUS/ASC-US were high-risk HPV positive (range 23-74%). In women with LSIL, the pooled positivity rate was 76% (95% CI: 71-81%; range 55-89%). In spite of considerable inter-study heterogeneity, the difference in HPV positivity between the two triage groups was large and highly significant: 32% (95% CI: 27-38%). HPV rates dropped tremendously as age and cutoffs of test positivity increased. Other factors (cytological classification system, country, continent, collection method and year of publication) had no statistically significant impact, except in LSIL triage where HPV positivity was significantly lower in European compared to American studies. Women with LSIL, especially younger women, have high HPV positivity rates suggesting limited utility of reflex HPV triaging these cases. Research is needed to identify more specific methods to triage women with low-grade squamous cervical lesions
Effect of Re-impacting Debris on the Solidification of the Lunar Magma Ocean
Anorthosites that comprise the bulk of the lunar crust are believed to have
formed during solidification of a Lunar Magma Ocean (LMO) in which these rocks
would have floated to the surface. This early flotation crust would have formed
a thermal blanket over the remaining LMO, prolonging solidification.
Geochronology of lunar anorthosites indicates a long timescale of LMO cooling,
or re-melting and re-crystallization in one or more late events. To better
interpret this geochronology, we model LMO solidification in a scenario where
the Moon is being continuously bombarded by returning projectiles released from
the Moon-forming giant impact. More than one lunar mass of material escaped the
Earth-Moon system onto heliocentric orbits following the giant impact, much of
it to come back on returning orbits for a period of 100 Myr. If large enough,
these projectiles would have punctured holes in the nascent floatation crust of
the Moon, exposing the LMO to space and causing more rapid cooling. We model
these scenarios using a thermal evolution model of the Moon that allows for
production (by cratering) and evolution (solidification and infill) of holes in
the flotation crust that insulates the LMO. For effective hole production,
solidification of the magma ocean can be significantly expedited, decreasing
the cooling time by more than a factor of 5. If hole production is inefficient,
but shock conversion of projectile kinetic energy to thermal energy is
efficient, then LMO solidification can be somewhat prolonged, lengthening the
cooling time by 50% or more
The SCUBA Bright Quasar Survey (SBQS): 850micron observations of the z>4 sample
We present initial results of a new, systematic search for massive
star-formation in the host galaxies of the most luminous and probably most
massive z>=4 radio-quiet quasars (M(B) 10^13Lsun).
A total of 38 z>=4 radio-quiet quasars have been observed at the JCMT using
SCUBA at 850microns: 8 were detected (>3sigma) with S(850microns)>~ 10mJy
(submillimetre-loud). The new detections almost triple the number of optically
selected, submillimetre-loud z>~4 radio-quiet quasars known to date. We include
a detailed description of how our quasar sample is defined in terms of radio
and optical properties.
There is no strong evidence for trends in either detectability or 850microns
flux with absolute magnitude, M(B). We find that the weighted mean flux of the
undetected sources is 2.0 +/- 0.6mJy, consistent with an earlier estimate of
\~3mJy based on more sensitive observations of a sample z>~4 radio-quiet
quasars (McMahon et al., 1999). This corresponds to an inferred starformation
rate of \~1000Msun/yr, similar to Arp220. The typical starformation timescale
for the submillimetre-bright sources is ~1Gyr, 10 times longer than the typical
accretion-driven e-folding timescale of ~5x10^7 years. Our 850micron detection
of the z=4.4 quasar PSS J1048+4407 when analysed in conjunction with 1.2mm
single-dish and interferometric observations suggests that this source is
resolved on angular scales of 1-2" (6-12 kpc). In addition, we present a new
optical spectrum of this source, identifying it as a broad absorption line
(BAL) quasar. The new redshift is outside that covered in a recent CO line
search by Guilloteau et al., (1999), highlighting the need for accurate
redshifts for the obervation and interpretation of high-redshift line studies.Comment: 16 pages, 11 figures. Accepted by Monthly Notices of the Royal
Astronomical Societ
Female Barrenness, Bodily Access and Aromatic Treatments in Seventeenth-Century England
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, CC BY-NC-ND 3.0 which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made, see https://creativecommons.org/licenses/by-nc-nd/3.0/.Scholars examining medical practice in early modern England have often remarked upon the complexities of the relationship between male physicians and female patients. It has been noted that ideas of female modesty and concern about the potential erotic nature of contact between patients and practitioners could affect the treatment of certain disorders. This paper contributes to this on-going discussion by examining the use of pungent substances to diagnose and treat female barrenness. Diagnostic tests included in medical treatises could rely upon the woman’s ability to perceive a particular substance. These tests thus put women at the centre of the diagnosis of their disorders and allowed them to negotiate access to their reproductive bodies. Similarly medical practitioners included a range of treatments for infertility that involved the fumes of certain substances entering the womb or surrounding the body. These treatments may have allowed women, and perhaps their medical practitioners, to choose a method of remedy that did not involve the application of external lotions to the genitalia. Thus by considering the multi-sensory nature of medical treatment this paper will highlight that the diversity of remedies advocated in early modern medical texts would perhaps have allowed women to restrict access to their reproductive bodies, while still obtaining diagnosis and treatment.Peer reviewe
EMDR as a treatment for long term depression: a feasibility study
Objective. Current treatments for long-term depression – medication and psy-chotherapy – are effective for some but not all clients. New approaches need to bedeveloped to complement the ones already available. This study was designed to test thefeasibility of using an effective post-traumatic stress disorder treatment for people withlong-term depression.
Design. A single-case experimental design with replications was undertaken as afeasibility study of eye movement desensitization and reprocessing (EMDR) in treatinglong-term depression.
Methods. Thirteen people with recurrent and/or long-term depression were recruitedfrom primary care mental health services and given standard protocol EMDR for amaximum of 20 sessions. Levels of depression were measured before and after treatmentand at follow-up, clients also rated their mood each day.
Results. Eight people engaged with the treatment; seven of these had clinically significantand statistically reliable improvement on the Hamilton Rating Scale for Depression. Dailymood ratings were highly variable both during baseline and intervention.
Conclusions. EMDR is a feasible treatment for recurrent and/or long-term depression.Research on treatment efficacy and effectiveness is now required
X-ray absorption spectroscopy systematics at the tungsten L-edge
A series of mononuclear six-coordinate tungsten compounds spanning formal oxidation states from 0 to +VI, largely in a ligand environment of inert chloride and/or phosphine, has been interrogated by tungsten L-edge X-ray absorption spectroscopy. The L-edge spectra of this compound set, comprised of [W<sup>0</sup>(PMe<sub>3</sub>)<sub>6</sub>], [W<sup>II</sup>Cl<sub>2</sub>(PMePh<sub>2</sub>)<sub>4</sub>], [W<sup>III</sup>Cl<sub>2</sub>(dppe)<sub>2</sub>][PF<sub>6</sub>] (dppe = 1,2-bis(diphenylphosphino)ethane), [W<sup>IV</sup>Cl<sub>4</sub>(PMePh<sub>2</sub>)<sub>2</sub>], [W<sup>V</sup>(NPh)Cl<sub>3</sub>(PMe<sub>3</sub>)<sub>2</sub>], and [W<sup>VI</sup>Cl<sub>6</sub>] correlate with formal oxidation state and have usefulness as references for the interpretation of the L-edge spectra of tungsten compounds with redox-active ligands and ambiguous electronic structure descriptions. The utility of these spectra arises from the combined correlation of the estimated branching ratio (EBR) of the L<sub>3,2</sub>-edges and the L<sub>1</sub> rising-edge energy with metal Z<sub>eff</sub>, thereby permitting an assessment of effective metal oxidation state. An application of these reference spectra is illustrated by their use as backdrop for the L-edge X-ray absorption spectra of [W<sup>IV</sup>(mdt)<sub>2</sub>(CO)<sub>2</sub>] and [W<sup>IV</sup>(mdt)<sub>2</sub>(CN)<sub>2</sub>]<sup>2–</sup> (mdt<sup>2–</sup> = 1,2-dimethylethene-1,2-dithiolate), which shows that both compounds are effectively W<sup>IV</sup> species. Use of metal L-edge XAS to assess a compound of uncertain formulation requires: 1) Placement of that data within the context of spectra offered by unambiguous calibrant compounds, preferably with the same coordination number and similar metal ligand distances. Such spectra assist in defining upper and/or lower limits for metal Z<sub>eff</sub> in the species of interest; 2) Evaluation of that data in conjunction with information from other physical methods, especially ligand K-edge XAS; 3) Increased care in interpretation if strong π-acceptor ligands, particularly CO, or π-donor ligands are present. The electron-withdrawing/donating nature of these ligand types, combined with relatively short metal-ligand distances, exaggerate the difference between formal oxidation state and metal Z<sub>eff</sub> or, as in the case of [W<sup>IV</sup>(mdt)<sub>2</sub>(CO)<sub>2</sub>], add other subtlety by modulating the redox level of other ligands in the coordination sphere
Examination of the recommended safe and unsafe zone for placement of surgical instruments in thoracentesis and video-assisted thoracic surgery: a cadaveric study
Background: Thoracentesis and video-assisted thoracic surgery procedures can result in haemorrhage as a consequence of severing the collateral branches of the posterior intercostal artery. These branches have been shown to be most common in the 5th intercostal space (ICS). Tortuosity has been shown to be especially prevalent nearer to midline. A group of investigators have recommended the 4th and 7th ICS, 120 mm lateral to midline as a safe zone, least likely to hit branches when cutting into the ICS. The present study aimed to investigate that safe zone as a better entry points for procedures. In addition, investigation of the least safe 5th ICS was also performed.
Materials and methods: A total of 56 embalmed human cadavers were selected for the study. With the cadavers laid prone, 2 cm incisions were made at the 4th, 5th and 7th ICS, 120 mm lateral to midline bilaterally. The cadavers were then placed supine and the incisions were dissected. Careful attention was paid to identify if any collateral branches were cut.
Results: After thorough dissection of the 4th, 5th and 7th ICS incision sites, it was shown that damage to the 5th intercostal was seen most frequently.
Conclusions: Based on this cadaveric study, a 2 cm incision at the 4th, 5th and 7th ICS 120 mm lateral from midline resulted in the most damage at the level of the 5th ICS. The 4th ICS had the least damage seen. Therefore, it is recommended that insertion should be placed at the level of the 4th ICS bilaterally
Catalytic Cycle of Multicopper Oxidases Studied by Combined Quantum- and Molecular-Mechanical Free-Energy Perturbation Methods
We have used combined quantum mechanical and molecular mechanical free-energy perturbation
methods in combination with explicit solvent simulations to study the reaction mechanism of the
multicopper oxidases, in particular the regeneration of the reduced state from the native
intermediate. For 52 putative states of the trinuclear copper cluster, differing in the oxidation states
of the copper ions and the protonation states of water- and O2-derived ligands, we have studied
redox potentials, acidity constants, isomerisation reactions, as well as water- and O2 binding
reactions. Thereby, we can propose a full reaction mechanism of the multicopper oxidases with
atomic detail. We also show that the two copper sites in the protein communicate so that redox
potentials and acidity constants of one site are affected by up to 0.2 V or 3 pKa units by a change
in the oxidation state of the other site
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