Ab initio linear scaling response theory: Electric polarizability by perturbed projection

A linear scaling method for calculation of the static {\em ab inito} response within self-consistent field theory is developed and applied to calculation of the static electric polarizability. The method is based on density matrix perturbation theory [Niklasson and Challacombe, cond-mat/0311591], obtaining response functions directly via a perturbative approach to spectral projection. The accuracy and efficiency of the linear scaling method is demonstrated for a series of three-dimensional water clusters at the RHF/6-31G** level of theory. Locality of the response under a global electric field perturbation is numerically demonstrated by approximate exponential decay of derivative density matrix elements.Comment: 4.25 pages in PRL format, 2 figure

Estimation and Uncertainty Assessment of Surface Microclimate Indicators at Local Scale Using Airborne Infrared Thermography and Multispectral Imagery

A precise estimation and the characterization of the spatial variability of microclimate conditions (MCCs) are essential for risk assessment and site-specific management of vector-borne diseases and crop pests. The objective of this study was to estimate at local scale, and assess the uncertainties of Surface Microclimate Indicators (SMIs) derived from airborne infrared thermography and multispectral imaging. SMIs including Surface Temperature (ST) were estimated in southern Quebec, Canada. The formulation of their uncertainties was based on in-situ observations and the law of propagation of uncertainty. SMIs showed strong local variability and intra-plot variability of MCCs in the study area. The ST values ranged from 290 K to 331 K. They varied more than 17 K on vegetable crop fields. The correlation between ST and in-situ observations was very high (r = 0.99, p = 0.010). The uncertainty and the bias of ST compared to in-situ observations were 0.73 K and ±1.42 K respectively. This study demonstrated that very high spatial resolution multispectral imaging and infrared thermography present a good potential for the characterization of the MCCs that govern the abundance and the behavior of disease vectors and crop pests in a given area

Epidemiology and clinical aspects of hematological malignancies at the military hospital of Antananarivo

Background: Malignant hemopathies constitute a group of pathologies having in common the anomalies of the bone marrow or of the lymphatic system cells. In developed countries, the number and actual distribution of cancers is provided by cancer registries. In Madagascar there is no effective cancer registry and only two studies on malignant hemopathies have been carried out to date, but neither has described their epidemiology and clinical aspects. Thus, we aimed to describe the epidemiology and clinical aspects of malignant hemopathies managed in the Medical Oncology Unit of the Military Hospital of Antananarivo.Methods: It was a cross-sectional and descriptive study carried out at this unit from 1st December 2012 to 31st August 2015 (33 months). Authors included all patients followed, then excluded those without pathologic evidence, cases of monoclonal gammapathy of unknown significance and cases of solid cancers.Results: We followed up 57 cases of malignant hemopathies. The mean age was 49.39±15.46 years and the sex ratio was 1.71. Superficial lymphadenopathy was the most frequent warning signs (31.58%) and lymphomas were most represented (52.63%). There was a significant association between warning signs and diagnosis (p value <0.001).Conclusions: Present results are grossly similar to those of other African authors. Present results are distinguished by a low proportion of chronic myeloid leukemia and a very low proportion of chronic lymphocytic leukemia compared to literature data. The effectiveness of the cancer registry will allow us to improve the knowledge about frequency and current distribution of cancer in Madagascar

A portable infrared laser spectrometer for flux measurements of trace gases at the geosphere-atmosphere interface

International audienceA portable infrared laser absorption spectrometer named SPIRIT (SPectrom'etre Infra-Rouge In situ Troposph'erique) has been set up for the simultaneous flux measurements of trace gases at the geosphere-atmosphere interface. It uses a continuous wave distributed feedback room temperature quantum cascade laser and a patented new optical multi-pass cell. The aim of SPIRIT field studies is to get a better understanding of land and water bodies to atmosphere exchange mechanisms of greenhouse gases (GHG). The analytical procedures to derive concentrations and fluxes are described, as well as the performances of the instrument under field conditions. The ability of SPIRIT to assess space and time dependence emissions of two GHG--nitrous oxide (N2O) and methane (CH4)--for different types of ecosystems is demonstrated through in situ measurements on peatland, on fertilized soil, and on water body systems. The objectives of these investigations and preliminary significant results are reported

Solvent contribution to the stability of a physical gel characterized by quasi-elastic neutron scattering

The dynamics of a physical gel, namely the Low Molecular Mass Organic Gelator {\textit Methyl-4,6-O-benzylidene-$\alpha$ -D-mannopyranoside ($\alpha$-manno)} in water and toluene are probed by neutron scattering. Using high gelator concentrations, we were able to determine, on a timescale from a few ps to 1 ns, the number of solvent molecules that are immobilised by the rigid network formed by the gelators. We found that only few toluene molecules per gelator participate to the network which is formed by hydrogen bonding between the gelators' sugar moieties. In water, however, the interactions leading to the gel formations are weaker, involving dipolar, hydrophobic or $\pi-\pi$ interactions and hydrogen bonds are formed between the gelators and the surrounding water. Therefore, around 10 to 14 water molecules per gelator are immobilised by the presence of the network. This study shows that neutron scattering can give valuable information about the behaviour of solvent confined in a molecular gel.Comment: Langmuir (2015

Giant capsids from lattice self-assembly of cyclodextrin complexes

Proteins can readily assemble into rigid, crystalline and functional structures such as viral capsids and bacterial compartments. Despite ongoing advances, it is still a fundamental challenge to design and synthesize protein-mimetic molecules to form crystalline structures. Here we report the lattice self-assembly of cyclodextrin complexes into a variety of capsidlike structures such as lamellae, helical tubes and hollow rhombic dodecahedra. The dodecahedral morphology has not hitherto been observed in self-assembly systems. The tubes can spontaneously encapsulate colloidal particles and liposomes. The dodecahedra and tubes are respectively comparable to and much larger than the largest known virus. In particular, the resemblance to protein assemblies is not limited to morphology but extends to structural rigidity and crystallinity-a well-defined, 2D rhombic lattice of molecular arrangement is strikingly universal for all the observed structures. We propose a simple design rule for the current lattice self-assembly, potentially opening doors for new protein-mimetic materials

Assessing Communities of Practice in health policy : A conceptual framework as a first step towards empirical research

Peer reviewe

Variation of the chemical composition of four forage shrubs (Albizia lebbeck, Leucaena leucocephala, Morinda lucida and Senna siamea) in dry season in southeast of Gabon

Objective: This study is conducted, to know the chemical composition at different periods of the dry season, of four major fodder shrubs (Albizia lebbeck, Leucaena leucocephala, Morinda lucida and Senna siamea), used to supplement poor fodders in animal feed, in the conditions of southeast Gabon.Methodology and results: The leaves of each species were harvested at the beginning, at mid-season and at the end of dry season. They were dried and crushed to determine their chemical composition. The results showed that, with A. lebbeck, the levels of DM obtained at mid-season and the end that one, were higher (P&lt;0.05) than at the first harvest. The levels of DM and CP obtained at mid-season and the end of dry season, with L. leucocephala were higher (p&lt;0.05) than those observed at beginning. Variations of DM and CP levels of M. lucida leaves and DM content of S. siamea leaves were not significant (p&gt;0.05). In addition, catechic tannins were not found in the leaves of S. siamea. However, the variations of this tannins type, observed in the leaves of L. leucocephala, M. lucida and A. lebbeck were not significant (p&gt;0.05). On the other hand, the contents of gallic tannins measured in the leaves of S. siamea decreased at the end of the dry season (p&lt;0.05).Conclusion: Finally, it appears that these species showed few variations in protein, cellulose and tannins throughout the dry season. Taking into account the results obtained, the shrub species studied could constitute good forage in supplementation of poor grass in the dry season. However, L. leucocephala and S. siamea should be used with much moderation for the feeding of ruminants, given the presence of gallic tannins in their leaves. Nevertheless, it would be important to study the digestibility of these forages in the dry season.Key words: legumes, fabaceae, rubiaceae, ruminants, tannins

Les Houches 2011: Physics at TeV Colliders New Physics Working Group Report

We present the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our report includes new agreements on formats for interfaces between computational tools, new tool developments, important signatures for searches at the LHC, recommendations for presentation of LHC search results, as well as additional phenomenological studies.Comment: 243 pages, report of the Les Houches 2011 New Physics Group; fix three figure