1,784 research outputs found
Economic and environmental analysis of the introduction of legumes in livestock farming systems
Legumes in low input systems are becoming increasingly important. The socioeconomic implication of the adoption of novel legumes species has been assessed in sheep and dairy cattle grazing systems in Europe using a biological model which has been linked to linear programming models. In the economic sub-model, the mathematical programming models produce an economic evaluation of the legumes in a farming system context, emphasising the land allocation and the availability of nutrients during the different seasons of the production cycle. Then the paper evaluates the impact of adopting the legumes on the regional income and production. In the UK and Germany, the introduction of legumes results in sizeable gains for the farmers whereas in Italy and France the gains are smaller
Statistical Properties of Gamma-Ray Burst Polarization
The emission mechanism and the origin and structure of magnetic fields in
gamma-ray burst (GRB) jets are among the most important open questions
concerning the nature of the central engine of GRBs. In spite of extensive
observational efforts, these questions remain to be answered and are difficult
or even impossible to infer with the spectral and lightcurve information
currently collected. Polarization measurements will lead to unambiguous answers
to several of these questions. Recent developments in X-ray and gamma-ray
polarimetry techniques have demonstrated a significant increase in sensitivity
enabling several new mission concepts, e.g. POET (Polarimeters for Energetic
Transients), providing wide field of view and broadband polarimetry
measurements. If launched, missions of this kind would finally provide
definitive measurements of GRB polarizations. We perform Monte Carlo
simulations to derive the distribution of GRB polarizations in three emission
models; the synchrotron model with a globally ordered magnetic field (SO
model), the synchrotron model with a locally random magnetic field (SR model),
and the Compton drag model (CD model). The results show that POET, or other
polarimeters with similar capabilities, can constrain the GRB emission models
by using the statistical properties of GRB polarizations. In particular, the
ratio of the number of GRBs for which the polarization degrees can be measured
to the number of GRBs that are detected (N_m/N_d) and the distributions of the
polarization degrees (Pi) can be used as the criteria. If N_m/N_d > 30% and Pi
is clustered between 0.2 and 0.7, the SO model will be favored. If instead
N_m/N_d < 15%, then the SR or CD model will be favored. If several events with
Pi > 0.8 are observed, then the CD model will be favored.Comment: Replaced with accepted version in ApJ. A few minor changes done.
References adde
On the construction of model Hamiltonians for adiabatic quantum computation and its application to finding low energy conformations of lattice protein models
In this report, we explore the use of a quantum optimization algorithm for
obtaining low energy conformations of protein models. We discuss mappings
between protein models and optimization variables, which are in turn mapped to
a system of coupled quantum bits. General strategies are given for constructing
Hamiltonians to be used to solve optimization problems of
physical/chemical/biological interest via quantum computation by adiabatic
evolution. As an example, we implement the Hamiltonian corresponding to the
Hydrophobic-Polar (HP) model for protein folding. Furthermore, we present an
approach to reduce the resulting Hamiltonian to two-body terms gearing towards
an experimental realization.Comment: 35 pages, 8 figure
739 observed NEAs and new 2-4m survey statistics within the EURONEAR network
We report follow-up observations of 477 program Near-Earth Asteroids (NEAs)
using nine telescopes of the EURONEAR network having apertures between 0.3 and
4.2 m. Adding these NEAs to our previous results we now count 739 program NEAs
followed-up by the EURONEAR network since 2006. The targets were selected using
EURONEAR planning tools focusing on high priority objects. Analyzing the
resulting orbital improvements suggests astrometric follow-up is most important
days to weeks after discovery, with recovery at a new opposition also valuable.
Additionally we observed 40 survey fields spanning three nights covering 11 sq.
degrees near opposition, using the Wide Field Camera on the 2.5m Isaac Newton
Telescope (INT), resulting in 104 discovered main belt asteroids (MBAs) and
another 626 unknown one-night objects. These fields, plus program NEA fields
from the INT and from the wide field MOSAIC II camera on the Blanco 4m
telescope, generated around 12,000 observations of 2,000 minor planets (mostly
MBAs) observed in 34 square degrees. We identify Near Earth Object (NEO)
candidates among the unknown (single night) objects using three selection
criteria. Testing these criteria on the (known) program NEAs shows the best
selection methods are our epsilon-miu model which checks solar elongation and
sky motion and the MPC's NEO rating tool. Our new data show that on average 0.5
NEO candidates per square degree should be observable in a 2m-class survey (in
agreement with past results), while an average of 2.7 NEO candidates per square
degree should be observable in a 4m-class survey (although our Blanco
statistics were affected by clouds). At opposition just over 100 MBAs (1.6
unknown to every 1 known) per square degree are detectable to R=22 in a 2m
survey based on the INT data, while our two best ecliptic Blanco fields away
from opposition lead to 135 MBAs (2 unknown to every 1 known) to R=23.Comment: Published in Planetary and Space Sciences (Sep 2013
Exploring the coordination chemistry of isomerizable terpyridine derivatives for successful analyses of cis and trans isomers by travelling wave ion mobility mass spectrometry
The photochemical cis-trans isomerization of the 4-{4-[2-(pyridin-4-yl)ethenyl]phenyl}-2,2': 6',2''-terpyridine ligand (vpytpy) was investigated by UV-vis, NMR and TWIM-MS. Ion mobility mass spectrometry was performed pursuing the quantification of the isomeric composition during photolysis, however an in-source trans-to-cis isomerization process was observed. In order to overcome this inherent phenomenon, the isomerization of the vpytpy species was suppressed by complexation, reacting with iron(II) ions, and forming the [Fe(vpytpy)(2)](2+) complex. The strategy of "freezing" the cis-trans isomerizable ligand at a given geometric conformation was effective, preventing further isomerization, thus allowing the distinction of each one of the isomers in the photolysed mixture. In addition, the experimental drift times were related to the calculated surface areas of the three possible cis-cis, cis-trans and trans-trans iron(II) complex isomers. The stabilization of the ligand in a given conformation also allows us to obtain the cis-cis and cis-trans complexes exhibiting the ligand in the metastable cis-conformation, as well as in the thermodynamically stable trans-conformation.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq
Daily-Life Monitoring of Stroke Survivors Motor Performance: The INTERACTION Sensing System
The objective of the INTERACTION Eu project is to develop and validate an unobtrusive and modular system for monitoring daily life activities, physical interactions with the environment and for training upper and lower extremity motor function in stroke subjects. This paper describes the development and preliminary testing of the project sensing platform made of sensing shirt, trousers, gloves and shoes. Modular prototypes were designed and built considering the minimal set of inertial, force and textile sensors that may enable an efficient monitoring of stroke patients. The single sensing elements are described and the results of their preliminary lab-level testing are reported
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A Photometric Redshift of z ~ 9.4 for GRB 090429B
Gamma-ray bursts (GRBs) serve as powerful probes of the early universe, with their luminous afterglows revealing the locations and physical properties of star-forming galaxies at the highest redshifts, and potentially locating first-generation (Population III) stars. Since GRB afterglows have intrinsically very simple spectra, they allow robust redshifts from low signal-to-noise spectroscopy, or photometry. Here we present a photometric redshift of z ~ 9.4 for the Swift detected GRB 090429B based on deep observations with Gemini-North, the Very Large Telescope, and the GRB Optical and Near-infrared Detector. Assuming a Small Magellanic Cloud dust law (which has been found in a majority of GRB sight lines), the 90% likelihood range for the redshift is 9.06 7. The non-detection of the host galaxy to deep limits (Y(AB) ~ 28, which would correspond roughly to 0.001L* at z = 1) in our late-time optical and infrared observations with the Hubble Space Telescope strongly supports the extreme-redshift origin of GRB 090429B, since we would expect to have detected any low-z galaxy, even if it were highly dusty. Finally, the energetics of GRB 090429B are comparable to those of other GRBs and suggest that its progenitor is not greatly different from those of lower redshift bursts
Silver sulfadiazine eradicates antibiotic-tolerant Staphylococcus aureus and Pseudomonas aeruginosa biofilms in patients with infected diabetic foot ulcers
Infections are among the most frequent and challenging events in diabetic foot ulcers (DFUs). Pathogenic bacteria growing in biofilms within host tissue are highly tolerant to environmental and chemical agents, including antibiotics. The present study was aimed at assessing the use of silver sulfadiazine (SSD) for wound healing and infection control in 16 patients with DFUs harboring biofilm-growing Staphylococcus aureus and Pseudomonas aeruginosa. All patients received a treatment based on a dressing protocol including disinfection, cleansing, application of SSD, and application of nonadherent gauze, followed by sterile gauze and tibio-breech bandage, in preparation for toilet surgery after 30 days of treatment. Clinical parameters were analyzed by the T.I.M.E. classification system. In addition, the activity of SSD against biofilm-growing S. aureus and P. aeruginosa isolates was assessed in vitro. A total of 16 patients with S. aureus and P. aeruginosa infected DFUs were included in the study. Clinical data showed a statistically significant (p < 0.002) improvement of patientsâ DFUs after 30 days of treatment with SSD with significant amelioration of all the parameters analyzed. Notably, after 30 days of treatment, resolution of infection was observed in all DFUs. In vitro analysis showed that both S. aureus and P. aeruginosa isolates developed complex and highly structured biofilms. Antibiotic susceptibility profiles indicated that biofilm cultures were significantly (p †0.002) more tolerant to all tested antimicrobials than their planktonic counterparts. However, SSD was found to be effective against fully developed biofilms of both S. aureus and P. aeruginosa at concentrations below those normally used in clinical preparations (10 mg/mL). These results strongly suggest that the topical administration of SSD may represent an effective alternative to conventional antibiotics for the successful treatment of DFUs infected by biofilm-growing S. aureus and P. aeruginosa
GRB Polarimetry with POET
POET (Polarimeters for Energetic Transients) represents a concept for a Small Explorer (SMEX) satellite mission, whose principal scientific goal is to understand the structure of GRB sources through sensitive Xâray and Îłâray polarization measurements. The payload consists of two wide fieldâofâview (FoV) instruments: a Low Energy Polarimeter (LEP) capable of polarization measurements in the energy range from 2â15 keV and a high energy polarimeter (GammaâRay Polarimeter Experiment or GRAPE) that would measure polarization in the 60â500 keV energy range. The POET spacecraft provides a zenithâpointed platform for maximizing the exposure to deep space. Spacecraft rotation provides a means of effectively dealing with any residual systematic effects in the polarization response. POET provides sufficient sensitivity and sky coverage to measure statistically significant polarization (for polarization levels in excess of 20%) for âŒ80 GRBs in a twoâyear mission. High energy polarization data would also be obtained for SGRs, solar flares, pulsars and other sources of astronomical interest
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