1,944 research outputs found
Environmental leadership and consciousness development : a case study among canadian SMEs
The objective of this paper is to explore how the various stages of consciousness development of top managers can influence, in practical terms, their abilities in and commitment to environmental leadership in different types of SMEs. A case study based on 63 interviews carried out in 15 industrial SMEs showed that the organizations that displayed the most environmental management practices were mostly run by managers at a post-conventional stage of consciousness development. Conversely, the SMEs that displayed less sustainable environmental management practices were all run by managers at conventional stages of development. Drawing upon diverse examples of environmental leadership, this paper analyzes the reasons why the stages of post-conventional consciousness development of top managers seem to foster corporate greening in SMEs. The study also sheds light on the key values and abilities associated with both environmental leadership and the upper-stages of consciousness development, which include a broader and systemic perspective, long-range focus, integration of conflicting goals, collaboration with stakeholders, complexity management, collaborative learning, among others
Baryon masses with dynamical twisted mass fermions
We present results on the mass of the nucleon and the using two
dynamical degenerate twisted mass quarks. The evaluation is performed at four
quark masses corresponding to a pion mass in the range of 690-300 MeV on
lattices of size 2.1 fm and 2.7 fm. We check for cutoff effects by evaluating
these baryon masses on lattices of spatial size 2.1 fm with lattice spacings
fm and fm, determined from
the pion sector and find them to be within our statistical errors. Lattice
results are extrapolated to the physical limit using continuum chiral
perturbation theory.
The nucleon mass at the physical point provides a determination of the
lattice spacing. Using heavy baryon chiral perturbation theory at we find fm, with a systematic error due to
the chiral extrapolation estimated to be about the same as the statistical
error. This value of the lattice spacing is in good agreement with the value
determined from the pion sector. We check for isospin breaking in the
-system. We find that and are almost
degenerate pointing to small flavor violating effects.Comment: 7 pages, 9 figures. Talk presented at the XXV International Symposium
on Lattice Field Theory, July 30 - August 4 2007, Regensburg, German
The Eight Modes of Local Governance in West Africa
Used in an analytical and non?normative way, the concept of governance may be taken to refer to any organised method of delivering public or collective services and goods according to specific logics and norms, and to specific forms of authority. This article applies the concept to analysis of local arenas in which public goods and services are delivered or co?delivered in Niger and other countries of West Africa. The analysis proposes eight ‘modes of local governance’ and describes their main characteristics drawing on fieldwork evidence collected over an extended period. Chiefly, associational, municipal (municipal council), project?based, bureaucratic, sponsorship?based, religious and merchant modes of governance are distinguished. The article concludes by defining and delimiting a concept of local political culture, referring to a set of shared modern practices and representations relating to the practical operation of modes of local governance in specific local arenas
Major role of iron uptake systems in the intrinsic extra-intestinal virulence of the genus Escherichia revealed by a genome-wide association study
The genus Escherichia is composed of several species and cryptic clades, including E. coli, which behaves as a vertebrate gut commensal, but also as an opportunistic pathogen involved in both diarrheic and extra-intestinal diseases. To characterize the genetic determinants of extra-intestinal virulence within the genus, we carried out an unbiased genome-wide association study (GWAS) on 370 commensal, pathogenic and environmental strains representative of the Escherichia genus phylogenetic diversity and including E. albertii (n = 7), E. fergusonii (n = 5), Escherichia clades (n = 32) and E. coli (n = 326), tested in a mouse model of sepsis. We found that the presence of the high-pathogenicity island (HPI), a similar to 35 kbp gene island encoding the yersiniabactin siderophore, is highly associated with death in mice, surpassing other associated genetic factors also related to iron uptake, such as the aerobactin and the sitABCD operons. We confirmed the association in vivo by deleting key genes of the HPI in E. coli strains in two phylogenetic backgrounds. We then searched for correlations between virulence, iron capture systems and in vitro growth in a subset of E. coli strains (N = 186) previously phenotyped across growth conditions, including antibiotics and other chemical and physical stressors. We found that virulence and iron capture systems are positively correlated with growth in the presence of numerous antibiotics, probably due to co-selection of virulence and resistance. We also found negative correlations between virulence, iron uptake systems and growth in the presence of specific antibiotics (i.e. cefsulodin and tobramycin), which hints at potential "collateral sensitivities" associated with intrinsic virulence. This study points to the major role of iron capture systems in the extra-intestinal virulence of the genus Escherichia. Author summary Bacterial isolates belonging to the genus Escherichia can be human commensals but also opportunistic pathogens, with the ability to cause extra-intestinal infection. There is therefore the need to identify the genetic elements that favour extra-intestinal virulence, so that virulent bacterial isolates can be identified through genome analysis and potential treatment strategies be developed. To reduce the influence of host variability on virulence, we have used a mouse model of sepsis to characterize the virulence of 370 strains belonging to the genus Escherichia, for which whole genome sequences were also available. We have used a statistical approach called Genome-Wide Association Study (GWAS) to show how the presence of genes that encode for iron scavenging are significantly associated with the propensity of a bacterial isolate to cause extra-intestinal infections. Taking advantage of previously generated growth data on a subset of the strains and its correlation to virulence we generated hypothesis on the relationship between iron scavenging and growth in the presence of various antimicrobials, which could have implications for developing new treatment strategies
Comparative static curing versus dynamic curing on tablet coating structures
International audienceCuring is generally required to stabilize film coating from aqueous polymer dispersion. This post-coating drying step is traditionally carried out in static conditions, requiring the transfer of solid dosage forms to an oven. But, curing operation performed directly inside the coating equipment stands for an attractive industrial application. Recently, the use of various advanced physico-chemical characterization techniques i.e., X-ray micro-computed tomography, vibrational spectroscopies (near infrared and Raman) and X-ray microdiffraction, allowed new insights into the film-coating structures of dynamically cured tablets. Dynamic curing end-point was efficiently determined after 4 h. The aim of the present work was to elucidate the influence of curing conditions on film-coating structures. Results demonstrated that 24 h of static curing and 4 h of dynamic curing, both performed at 60 degrees C and ambient relative humidity, led to similar coating layers in terms of drug release properties, porosity, water content, structural rearrangement of polymer chains and crystalline distribution. Furthermore, X-ray microdiffraction measurements pointed out different crystalline coating compositions depending on sample storage time. An aging mechanism might have occur during storage, resulting in the crystallization and the upward migration of cetyl alcohol, coupled to the downward migration of crystalline sodium lauryl sulfate within the coating layer. Interestingly, this new study clearly provided further knowledge into film-coating structures after a curing step and confirmed that curing operation could be performed in dynamic conditions
Identification of the bacteria and their metabolic activities associated with the microbial spoilage of custard cream desserts
The famous French dessert “ile flottante” consists of a sweet egg white foam floating on a vanilla custard cream,which contains highly nutritive raw materials, including milk, sugar and egg. Spoilage issues are therefore a keyconcern for the manufacturers. This study explored the bacterial diversity of 64 spoiled custard cream dessertsmanufactured by 2 French companies. B. cereus group bacteria, coagulase negative Staphylococcus, Enterococcus and Leuconostoc spp. were isolated from spoiled products. Thirty-one bacterial isolates representative of the main spoilage species were tested for their spoilage abilities. Significant growth and pH decrease were observed regardless of species. While off-odours were detected with B. cereus group and staphylococci, yoghurt odours were detected with Enterococcus spp. and Leuconostoc spp. B. cereus group bacteria produced various esters and several compounds derived from amino acid and sugar metabolism. Most Staphylococci produced phenolic compounds. Enterococcus spp. and Leuconostoc spp. isolates produced high levels of compounds derived from sugar metabolism. Each type of spoilage bacteria was associated with a specific volatile profile and lactic acid was identified as a potential marker of spoilage of custard cream-based desserts. These findings provide valuable information for manufacturers to improve food spoilage detection and prevention of chilled desserts made with milk and egg
Comprehensive study of dynamic curing effect on tablet coating structure
International audienceThe dissolution method is still widely used to determine curing end-points to ensure long-term stability of film coatings. Nevertheless, the process of curing has not yet been fully investigated. For the first time, joint techniques were used to elucidate the mechanisms of dynamic curing over time from ethylcellulose (Aquacoat (R))-based coated tablets. X-ray micro-computed tomography (X mu CT), Near Infrared (NIR), and Raman spectroscopies as well as X-ray microdiffraction were employed as non-destructive techniques to perform direct measurements on tablets. All techniques indicated that after a dynamic curing period of 4 h, reproducible drug release can be achieved and no changes in the microstructure of the coating were any longer detected. X mu CT analysis highlighted the reduced internal porosity, while both NIR and Raman measurements showed that spectral information remained unaltered after further curing. X-ray microdiffraction revealed densification of the coating layer with a decrease in the overall coating thickness of about 10 pm as a result of curing. In addition, coating heterogeneity attributed to cetyl alcohol was observed from microscopic images and Raman analysis. This observation was confirmed by X-ray microdiffraction that showed that crystalline cetyl alcohol melted and spread over the coating surface with curing. Prior to curing, X-ray microdiffraction also revealed the existence of two coating zones differing in crystalline cetyl alcohol and sodium lauryl sulfate concentrations which could be explained by migration of these constituents within the coating layer. Therefore, the use of non-destructive techniques allowed new insights into tablet coating structures and provided precise determination of the curing end-point compared to traditional dissolution testing. This thorough study may open up new possibilities for process and formulation control
Defective microtubule-dependent podosome organization in osteoclasts leads to increased bone density in Pyk2−/− mice
The protein tyrosine kinase Pyk2 is highly expressed in osteoclasts, where it is primarily localized in podosomes. Deletion of Pyk2 in mice leads to mild osteopetrosis due to impairment in osteoclast function. Pyk2-null osteoclasts were unable to transform podosome clusters into a podosome belt at the cell periphery; instead of a sealing zone only small actin rings were formed, resulting in impaired bone resorption. Furthermore, in Pyk2-null osteoclasts, Rho activity was enhanced while microtubule acetylation and stability were significantly reduced. Rescue experiments by ectopic expression of wild-type or a variety of Pyk2 mutants in osteoclasts from Pyk2−/− mice have shown that the FAT domain of Pyk2 is essential for podosome belt and sealing zone formation as well as for bone resorption. These experiments underscore an important role of Pyk2 in microtubule-dependent podosome organization, bone resorption, and other osteoclast functions
SNP analysis infers that recombination is involved in the evolution of Amitraz resistance in Rhipicephalus microplus
Rhipicephalus microplus, better known as the Asiatic cattle tick, is a largely invasive
ectoparasite of great economic importance due to the negative effect it has on agricultural
livestock on a global scale, particularly cattle. Tick-borne diseases (babesiosis and anaplasmosis)
transmitted by R. microplus are alarming as they decrease the quality of livestock
health and production. In sub-Saharan Africa, cattle represent a major source of meat and
milk, but this region of the world is severely affected by the Rhipicephalus microplus tick.
The principal method for tick control is the use of chemical acaricides, notably amitraz,
which was implemented in the 1990’s after resistance to other acaricides surfaced. However,
the efficiency of chemical control is hindered by an increase in the frequency of mutant
resistance alleles to amitraz in tick populations. Presently, the only way to assess amitraz
resistance is by means of larval packet tests, but this technique is time-consuming and not
particularly cost effective. The main aims of this study were three-fold. First, we attempted
to correlate two known SNPs in the octopamine/tyramine (OCT/Tyr) receptor with amitraz
resistance in South African field samples of R. microplus. Second, we calculated gametic
disequilibrium for these SNPs to determine whether they are randomly associated. Lastly,
we conducted a study to assess the evolutionary effects of recombination within the OCT/
Tyr receptor. Our results confirmed that the two SNPs are associated with amitraz resistance
in the South African tick strain, and that they are in gametic disequilibrium. Additionally,
recombination was detected in the OCT/Tyr receptor generating two recombinant haplotypes. These results are of concern to farmers in sub-Saharan Africa, and the emergence
of amitraz resistance should be closely monitored in future. Therefore, we present a
quick and affordable RFLP based diagnostic technique to assess amitraz resistance in field
samples of R. microplus.S1 Fig. Subpopulation structure of ticks across South Africa. Ticks from each farm were
placed into subpopulations (1–15) depending on the region from which they were collected.
Grid blocks were constructed 300 x 300 km over the country for accurate overall segregation of
populations. The farms from which tick samples were analyzed are indicated in the table, along
with their grid block number and province. Farm numbers correspond with sample number,
e.g. sample 44.1MF is sample 1 of female R. microplus from farm 44.S1 Table. GenBank accession numbers for all R. microplus OCT/Tyr receptor sequences.S2 Table. Genotypes of field samples of R. microplus ticks at the two published SNP positions.S3 Table. Rhipicephalus microplus larval packet test results.Funding was provided by (a) Gauteng
Department of Agriculture and Rural Development, C
Maritz-Olivier. (b) Zoetis South Africa (Pty) Ltd., C
Maritz-Olivier (c) National Research Foundation,
THRIP grant nr: 83890.http://www.plosone.orgam201
High Accuracy 65nm OPC Verification: Full Process Window Model vs. Critical Failure ORC
It is becoming more and more difficult to ensure robust patterning after OPC due to the continuous reduction of layout dimensions and diminishing process windows associated with each successive lithographic generation. Lithographers must guarantee high imaging fidelity throughout the entire range of normal process variations. The techniques of Mask Rule Checking (MRC) and Optical Rule Checking (ORC) have become mandatory tools for ensuring that OPC delivers robust patterning. However the first method relies on geometrical checks and the second one is based on a model built at best process conditions. Thus those techniques do not have the ability to address all potential printing errors throughout the process window (PW). To address this issue, a technique known as Critical Failure ORC (CFORC) was introduced that uses optical parameters from aerial image simulations. In CFORC, a numerical model is used to correlate these optical parameters with experimental data taken throughout the process window to predict printing errors. This method has proven its efficiency for detecting potential printing issues through the entire process window [1]. However this analytical method is based on optical parameters extracted via an optical model built at single process conditions. It is reasonable to expect that a verification method involving optical models built from several points throughout PW would provide more accurate predictions of printing errors for complex features. To verify this approach, compact optical models similar to those used for standard OPC were built and calibrated with experimental data measured at the PW limits. This model is then applied to various test patterns to predict potential printing errors. In this paper, a comparison between these two approaches is presented for the poly layer at 65 nm node patterning. Examples of specific failure predictions obtained separately with the two techniques are compared with experimental results. The details of implementing these two techniques on full product layouts are also included in this study
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