1,079 research outputs found
Strongly residual coordinates over A[x]
For a domain A of characteristic zero, a polynomial f over A[x] is called a
strongly residual coordinate if f becomes a coordinate (over A) upon going
modulo x, and f becomes a coordinate upon inverting x. We study the question of
when a strongly residual coordinate is a coordinate, a question closely related
to the Dolgachev-Weisfeiler conjecture. It is known that all strongly residual
coordinates are coordinates for n=2 . We show that a large class of strongly
residual coordinates that are generated by elementaries upon inverting x are in
fact coordinates for arbitrary n, with a stronger result in the n=3 case. As an
application, we show that all Venereau-type polynomials are 1-stable
coordinates.Comment: 15 pages. Some minor clarifications and notational improvements from
the first versio
Mass spectra of doubly heavy Omega_QQ' baryons
We evaluate the masses of baryons composed of two heavy quarks and a strange
quark with account for spin-dependent splittings in the framework of potential
model with the KKO potential motivated by QCD with a three-loop beta-function
for the effective charge consistent with both the perturbative limit at short
distances and linear confinement term at long distances between the quarks. The
factorization of dynamics is supposed and explored in the nonrelativistic
Schroedinger equation for the motion in the system of two heavy quarks
constituting the doubly heavy diquark and the strange quark interaction with
the diquark. The limits of approach, its justification and uncertainties are
discussed. Excited quasistable states are classified by the quantum numbers of
heavy diquark composed by the heavy quarks of the same flavor.Comment: 14 pages, revtex4-file, 3 eps-figures, 5 tables, typos correcte
Classification of protein interaction sentences via gaussian processes
The increase in the availability of protein interaction studies in textual format coupled with the demand for easier access to the key results has lead to a need for text mining solutions. In the text processing pipeline, classification is a key step for extraction of small sections of relevant text. Consequently, for the task of locating protein-protein interaction sentences, we examine the use of a classifier which has rarely been applied to text, the Gaussian processes (GPs). GPs are a non-parametric probabilistic analogue to the more popular support vector machines (SVMs). We find that GPs outperform the SVM and na\"ive Bayes classifiers on binary sentence data, whilst showing equivalent performance on abstract and multiclass sentence corpora. In addition, the lack of the margin parameter, which requires costly tuning, along with the principled multiclass extensions enabled by the probabilistic framework make GPs an appealing alternative worth of further adoption
Constraining the MSSM with universal gaugino masses and implication for searches at the LHC
Using a Markov chain Monte Carlo approach, we find the allowed parameter
space of a MSSM model with seven free parameters. In this model universality
conditions at the GUT scale are imposed on the gaugino sector. We require in
particular that the relic density of dark matter saturates the value extracted
from cosmological measurements assuming a standard cosmological scenario. We
characterize the parameter space of the model that satisfies experimental
constraints and illustrate the complementarity of the LHC searches, B-physics
observables and direct dark matter searches for further probing the parameter
space of the model. We also explore the different decay chains expected for the
coloured particles that would be produced at LHC.Comment: 29 pages, 11 figure
Synergy between industry and agriculture: techno-economic and life cycle assessments of waste recovery for crop growth in glasshouses
Controlled-environment agriculture in agro-industrial systems, where carbon dioxide, heat, and other wastes are recovered or recycled, has potential to be an environmentally friendly approach with economic feasibility. However, such approaches need careful exploration to ensure that environmental and economic benefits are maximised. Techno-economic, and life cycle assessments were applied to evaluate the synergy of producing crops (tomato and hemp) and recovering industrial wastes (e.g., heat and carbon dioxide) in glasshouses with robust uncertainty and sensitivity analyses. For each crop, two scenarios were compared, linear scenarios evaluated the use of raw materials with no waste recovery whereas circular scenarios captured industry flows and reused or recycled them in the glasshouse- avoiding raw materials consumption. Circular practices had a net benefit on the global warming potential for both crops, capturing up to 50,000 kg/y of CO2 in crops biomass and providing competitive product prices. The analysis showed that circular operational conditions can reduce, by almost half, the break-even product selling prices and sequester up to, approximately, 500 kg CO2eq./m2 of glasshouse if compared to linear systems. Future investments in this outstanding strategy to supply the United Kingdom's market demand of tomatoes could lead to a low-cost product and negative CO2eq. emissions by mitigating the importation of these products. Alongside, other impact categories scores may not be as favourable as the global warming potential, due to high impact of the waste management phase, chemical fertilisers, and pesticides utilisation
Healthcare Provider N95 Respirator Contamination Worn Behind Face Shields With SARS-CoV-2 During Routine Clinical Care of Patients With COVID-19
N95 respirator contamination with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during clinical care of patients with coronavirus disease 2019 is poorly understood. We performed a prospective observational study on healthcare provider's (HCP's) N95 respirators' and face shields' SARS-CoV-2 contamination during aerosol-generating procedures on SARS-CoV-2- positive patients housed in a COVID-19-specific unit. Medical masks worn on top of HCP's N95 respirators, and under face shields, during study aerosol-generating procedures were used as surrogates to detect contamination to avoid waste. Thirtythree HCPs were studied, and a total of 33 mask and 27 face shields were sampled. Masks were cut into 9 pieces and face shields were sampled twice, front and back, to determine locality of contamination; however, no positive samples were identified using standard polymerase chain reaction techniques with a CT value up to 40. All 9 mask piece samples were then pooled, as were face shield samples, using centrifugal concentration with polyethersulfone membranes. Once pooled and concentrated, overall, 9 (15%) samples were positive via real-time polymerase chain reaction: 5 from masks (15.2%) and 4 from face shields (14.8%)
Current constraints on Cosmological Parameters from Microwave Background Anisotropies
We compare the latest observations of Cosmic Microwave Background (CMB)
Anisotropies with the theoretical predictions of the standard scenario of
structure formation. Assuming a primordial power spectrum of adiabatic
perturbations we found that the total energy density is constrained to be
while the energy density in baryon and Cold Dark
Matter (CDM) are and ,
(all at 68% C.L.) respectively. The primordial spectrum is consistent with
scale invariance, () and the age of the universe is
Gyrs. Adding informations from Large Scale Structure and
Supernovae, we found a strong evidence for a cosmological constant
and a value of the Hubble parameter
. Restricting this combined analysis to flat universes, we put
constraints on possible 'extensions' of the standard scenario. A gravity waves
contribution to the quadrupole anisotropy is limited to be (95%
c.l.). A constant equation of state for the dark energy component is bound to
be (95% c.l.). We constrain the effective relativistic degrees
of freedom and the neutrino chemical potential and (massless neutrinos).Comment: The status of cosmological parameters before WMAP. In press on Phys.
Rev. D., Rapid Communication, 6 pages, 5 figure
Comparative Study of Erythrina indica Lam. (Febaceae) Leaves Extracts for Antioxidant Activity
The present study was designed to investigate the antioxidant activity of aqueous and methanol extracts of Erythrina indica Lam leaves by in vitro methods viz. 1, 1-Diphenyl-2-Picrylhydrazyl, nitric oxide radical scavenging activity, and inhibition of lipid peroxidation by thiobarbituric acid reactive substances (TBARS) method on isolated rat liver tissues. Quantitative analysis of antioxidative components like total amount of phenolics, flavonoids, and flavonols were estimated using the spectrophotometric method. Linear regression analysis was used to calculate the IC50 value. Results showed that the aqueous and methanol extracts exhibited significant DPPH radicals scavenging activity with an IC50 value 342.59 ± 19.59, 283.24 ± 12.28 µg/mL respectively. Nitric oxide radicals were significantly scavenged by the aqueous and methanol extracts (IC50 = 250.12 ± 10.66; 328.29 ± 3.74 µg/mL). Lipid peroxidation induced by the Fe2+ was inhibited by the aqueous extract with low IC50 value (97.29 ± 2.05 µg/mL) as compared to methanol extract (IC50 = 283.74 ± 5.70 µg/mL). Both the extracts were exhibited similar quantities of total phenolics. Total flavonoids were found to be in higher quantities than total flavonols in aqueous extract as compared to methanol extract. From the results, it is concluded that the aqueous and methanol extracts of E. indica leaves possesses significant antioxidant activity that may be due to the presence of flavonoids and related polyphenolic compounds
Fertility, Living Arrangements, Care and Mobility
There are four main interconnecting themes around which the contributions in this book are based. This introductory chapter aims to establish the broad context for the chapters that follow by discussing each of the themes. It does so by setting these themes within the overarching demographic challenge of the twenty-first century – demographic ageing. Each chapter is introduced in the context of the specific theme to which it primarily relates and there is a summary of the data sets used by the contributors to illustrate the wide range of cross-sectional and longitudinal data analysed
Structure, mass and stability of galactic disks
In this review I concentrate on three areas related to structure of disks in
spiral galaxies. First I will review the work on structure, kinematics and
dynamics of stellar disks. Next I will review the progress in the area of
flaring of HI layers. These subjects are relevant for the presence of dark
matter and lead to the conclusion that disk are in general not `maximal', have
lower M/L ratios than previously suspected and are locally stable w.r.t.
Toomre's Q criterion for local stability. I will end with a few words on
`truncations' in stellar disks.Comment: Invited review at "Galaxies and their Masks" for Ken Freeman's 70-th
birthday, Sossusvlei, Namibia, April 2010. A version with high-res. figures
is available at
http://www.astro.rug.nl/~vdkruit/jea3/homepage/Namibiachapter.pd
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