540 research outputs found
Experimental Hamiltonian identification for controlled two-level systems
We present a strategy to empirically determine the internal and control Hamiltonians for an unknown two-level system (black box) subject to various (piecewise constant) control fields when direct readout by measurement is limited to a single, fixed observable
From rods to helices: evidence of a screw-like nematic phase
Evidence of a special chiral nematic phase is provided using numerical
simulation and Onsager theory for systems of hard helical particles. This phase
appears at the high density end of the nematic phase, when helices are well
aligned, and is characterized by the C symmetry axes of the helices
spiraling around the nematic director with periodicity equal to the particle
pitch. This coupling between translational and rotational degrees of freedom
allows a more efficient packing and hence an increase of translational entropy.
Suitable order parameters and correlation functions are introduced to identify
this screw-like phase, whose main features are then studied as a function of
radius and pitch of the helical particles. Our study highlights the physical
mechanism underlying a similar ordering observed in colloidal helical flagella
[E. Barry et al. \textit{Phys. Rev. Lett.} \textbf{96}, 018305 (2006)] and
raises the question of whether it could be observed in other helical particle
systems, such as DNA, at sufficiently high densities.Comment: List of authors correcte
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A review of topical corticosteroid sprays for the treatment of inflammatory dermatoses
Background: Topical corticosteroids are available in many vehicles. However, patients' preference for vehicles are variable and could be tailored to maximize patient adherence. Spray vehicles may offer, convenience, and strong efficacy. Methods: A literature review was conducted using keywords: clobetasol, desoximetasone, betamethasone, triamcinolone, corticosteroid, topical, spray, vehicles, treatment, and clinical trial. Results: For moderate-to-severe plaque psoriasis, 87% of subjects achieved an Overall Disease Severity (ODS) Score ≤2 at week two and 78% achieved an ODS ≤1 after four weeks with clobetasol propionate (CP) 0.05% spray compared to 17% and 3% in the control group, respectively (P<0.001). For desoximetasone 0.25% spray, 31%-53% with moderate-to-severe psoriasis achieve Physician's Global Assessment (PGA) score ≤1 at day 28 versus 5%-18% in the vehicle spray group (P<0.01). For betamethasone dipropionate 0.05% spray, 19% with mild-to-moderate plaque psoriasis achieved an Investigator's Global Assessment (IGA) score ≤1 or a 2-grade reduction in IGA versus 2.3% in vehicle group (P≤0.001). For mild-to-severe steroid responsive inflammatory dermatoses, 64% using triamcinolone acetonide 0.2% spray achieved clear or almost clear skin at day 14 (no P value reported). Adverse events including burning, irritation, and dryness were similar across all corticosteroids
Optimizing Sequence Coverage for a Moderate Mass Protein in Nano-Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry
Sample pretreatment was optimized to obtain high sequence coverage for human serum albumin (HSA, 66.5 kDa) when using nano-electrospray ionization quadrupole time-of-flight mass spectrometry (nESI-Q-TOF-MS). Use of the final method with trypsin, Lys-C and Glu-C digests gave a combined coverage of 98.8%. The addition of peptide fractionation resulted in 99.7% coverage. These results were comparable to those obtained previously with matrixassisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The sample pretreatment/nESI-Q-TOF-MS method was also used with collision-induced dissociation to analyze HSA digests and to identify peptides that could be employed as internal mass calibrants in future studies of modifications to HSA
Optimizing Sequence Coverage for a Moderate Mass Protein in Nano-Electrospray Ionization Quadrupole Time-of-Flight Mass Spectrometry
Sample pretreatment was optimized to obtain high sequence coverage for human serum albumin (HSA, 66.5 kDa) when using nano-electrospray ionization quadrupole time-of-flight mass spectrometry (nESI-Q-TOF-MS). Use of the final method with trypsin, Lys-C and Glu-C digests gave a combined coverage of 98.8%. The addition of peptide fractionation resulted in 99.7% coverage. These results were comparable to those obtained previously with matrixassisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). The sample pretreatment/nESI-Q-TOF-MS method was also used with collision-induced dissociation to analyze HSA digests and to identify peptides that could be employed as internal mass calibrants in future studies of modifications to HSA
Scaling up index insurance for smallholder farmers: Recent evidence and insights
This report explores evidence and insights from five case studies that have made significant recent progress in addressing the challenge of insuring poor smallholder farmers and pastoralists in the developing world. In India, national index insurance programmes have reached over 30 million farmers through a mandatory link with agricultural credit and strong government support. In East Africa (Kenya, Rwanda and Tanzania), the Agriculture and Climate Risk Enterprise (ACRE) has recently scaled to reach nearly 200,000 farmers, bundling index insurance with agricultural credit and farm inputs. ACRE has built on strong partnerships with regional initiatives such as M-PESA mobile banking. In Ethiopia and Senegal, the R4 Rural Resilience Initiative has scaled unsubsidized index insurance to over 20,000 poor smallholder farmers who were previously considered uninsurable, using insurance as an integral part of a comprehensive risk management portfolio. With strong public and private sector support, the Mongolia Index-Based Livestock Insurance Project (IBLIP) insures more than 15,000 nomadic herders and links commercial insurance with a government disaster safety net. Finally, the Index-Based Livestock Insurance (IBLI) project in Kenya and Ethiopia demonstrates innovative approaches to insuring poor nomadic pastoralists in challenging circumstances.
A few common features appear to have contributed to recent progress within these case studies:
explicitly targeting obstacles to improving farmer income;
integration of insurance with other development interventions;
giving farmers a voice in the design of products;
investing in local capacity; and
investing in science-based index development.
Evidence from these case studies can inform the ongoing debate about the viability of scaling up index-based insurance for vulnerable smallholder farmers in the developing world. The rapid progress observed in recent years suggests that index insurance has the potential to benefit smallholder farmers at a meaningful scale, and suggests the need to reassess arguments that lack of demand and practical implementation challenges prevent index-based insurance from being a useful tool to reduce rural poverty
Studies of concentration and temperature dependencies of precipitation kinetics in iron-copper alloys using kinetic monte carlo and stochastic statistical simulations
The earlier-developed ab initio model and the kinetic Monte Carlo method
(KMCM) are used to simulate precipitation in a number of iron-copper alloys
with different copper concentrations x and temperatures T. The same simulations
are also made using the improved version of the earlier-suggested stochastic
statistical method (SSM). The results obtained enable us to make a number of
general conclusions about the dependencies of the decomposition kinetics in
Fe-Cu alloys on x and T. We also show that the SSM describes the precipitation
kinetics in a fair agreement with the KMCM, and employing the SSM in
conjunction with the KMCM enables us to extend the KMC simulations to the
longer evolution times. The results of simulations seem to agree with available
experimental data for Fe-Cu alloys within statistical errors of simulations and
the scatter of experimental results. Comparison of results of simulations to
experiments for some multicomponent Fe-Cu-based alloys enables us to make
certain conclusions about the influence of alloying elements in these alloys on
the precipitation kinetics at different stages of evolution.Comment: 18 pages, 17 postscript figures, LaTe
Clinical, Laboratory and Etiological Profile of Community Acquired Pneumonia in Elderly
Background: Community Acquired Pneumonia (CAP) is third leading cause of death in older people worldwide. Apart from typical symptoms the elderly present with atypical symptoms. The diagnosis of pneumonia and its treatment poses a challenge for clinicians. Aim and Objectives: The study was undertaken to study clinical, radiological and bacterial profile of CAP in elderly (> 60 years). Material and Methods: The elderly patient population consisted of 63 patients admitted with the diagnosis of CAP, as defined by British Thoracic society, were included in this prospective observational study over 24 months. Results: Among 63 patients, males were 38(60%) and females 25(40%), predominantly between the age group 60-74 years. Diabetes mellitus 12(19%) and anaemia 12(19%) were common co-morbidities. Cough 62(98%) was predominant presenting symptom. Patients presenting with atypical symptoms were 19(30%). Staphylococcus aureus was commonly isolated organism in 20(32%) patients on sputum examination. Left lower zone was commonly involved in 29(47%) on chest radiogram. The commonest complication was acute kidney injury in 9(15%).The overall mortality was 13% in this study group. Conclusion: CAP in elderly is a serious problem in clinical practice. In view of atypical presentation and associated co-morbidities, there is a delay in diagnosis, treatment initiation which may result in to high mortality. Early recognition, health education and awareness regarding pneumococcal vaccination are necessary
Crop type identification and spatial mapping using Sentinel-2 satellite data with focus on field-level information
Accurate monitoring of croplands helps in making decisions (for
insurance claims, crop management and contingency plans) at
the macro-level, especially in drylands where variability in cropping
is very high owing to erratic weather conditions. Dryland
cereals and grain legumes are key to ensuring the food and nutritional
security of a large number of vulnerable populations living
in the drylands. Reliable information on area cultivated to such
crops forms part of the national accounting of food production
and supply in many Asian countries, many of which are employing
remote sensing tools to improve the accuracy of assessments
of cultivated areas. This paper assesses the capabilities and limitations
of mapping cultivated areas in the Rabi (winter) season and
corresponding cropping patterns in three districts characterized
by small-plot agriculture. The study used Sentinel-2 Normalized
Difference Vegetation Index (NDVI) 15-day time-series at 10m
resolution by employing a Spectral Matching Technique (SMT)
approach. The use of SMT is based on the well-studied relationship
between temporal NDVI signatures and crop phenology. The
rabi season in India, dominated by non-rainy days, is best suited
for the application of this method, as persistent cloud cover will
hamper the availability of images necessary to generate clearly
differentiating temporal signatures. Our study showed that the
temporal signatures of wheat, chickpea and mustard are easily
distinguishable, enabling an overall accuracy of 84%, with wheat
and mustard achieving 86% and 94% accuracies, respectively. The
most significant misclassifications were in irrigated areas for mustard
and wheat, in small-plot mustard fields covered by trees and
in fragmented chickpea areas. A comparison of district-wise
national crop statistics and those obtained from this study
revealed a correlation of 96%
Electrostatic interactions mediate the nucleation and growth of a bacterial functional amyloid
Bacterial biofilm formation can have severe impacts on human and environmental health. Enteric bacteria produce functional amyloid fibers called curli that aid in biofilm formation and host colonization. CsgA is the major proteinaceous component of curli amyloid fibers and is conserved in many gram-negative enteric bacteria. The CsgA amyloid core consists of five imperfect repeats (R1-R5). R2, R3, and R4 have aspartic acid (D) and glycine (G) residues that serve as “gatekeeper” residues by modulating the intrinsic aggregation propensity of CsgA. Here, using mutagenesis, salt-mediated charge screening, and by varying pH conditions, we show that the ability of CsgA variants to nucleate and form amyloid fibers is dictated by the charge state of the gatekeeper residues. We report that in Citrobacter youngae CsgA, certain arginine (R) and lysine (K) residues also act as gatekeeper residues. A mechanism of gatekeeping is proposed wherein R and K residues electrostatically interact with negatively charged D residues, tempering CsgA fiber formation
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