2,391 research outputs found
Competition, quality and contract compliance: evidence from compulsory competitive tendering in local government in Great Britain, 1987-2000
The introduction of competition has frequently been found to cause costs to fall. There has, however, been a question as to whether this was partly achieved at the cost of quality. Auction theory predicts prices would fall more the greater the competition to provide the service. There has been some debate about whether the smaller budgets would make contract compliance more difficult. Evidence is found in support of this hypothesis. We also find some evidence that the better recorded performance of the in-house direct service organisations (DSOs) during this period was due to the information advantage they had from being incumbents
The Effects of Radiation Exposure: An in vivo vs in vitro Biomarker Study Analysis
Cells contain many genes that encode proteins which dictate the cell function. The thousands of genes expressed in a particular cell determine what the cell can do. When a cell is damaged, there are powerful mechanisms to repair damaged genes. Here, we investigated different cell lines that have been exposed to ionizing radiation (IR). To understand the effect of genes to different doses of IR and their correlations to up-regulated and down-regulated genes, a biomarker study has been performed on the following different cell types: In vivo lymphocytes from Metaiodobenzylguanidine (MIBG) isotopic radiation treated neuroblastoma patients and in vitro lymphoblastoid as well as fibroblast cells externally exposed to radiation. Results of the study concluded that qRT PCR analysis can be used to illustrate different trends between irradiated samples. The externally radiated in vitro lymphoblastoid and fibroblast samples showed positive fold change differences for the majority of transcripts studied. In addition, the fibroblast cells showed the highest expression of transcripts compared to the other two studies. This knowledge can be applied to accidental radiation exposures and other biodefense mechanisms. It allows us to understand the process of molecular changes, predict the outcome, and monitor radiation progression
Implications of the kinematical structure of circumnuclear star-forming regions on their derived properties
[Abbreviated] We review the results of high dispersion spectroscopy of 17
circumnuclear starforming regions (CNSFRs) in 3 nearby early spiral galaxies,
NGC2903, NGC3310 and NGC3351. We find that single Gaussian fitting to the
H and [OIII]5007A line profiles results in velocity dispersions around
32km/s and 52km/s, respectively, while the IR CaII triplet cross-correlation
technique provides stellar velocity dispersion values close to 50km/s. Even
though multiple kinematical components are present, the relation between gas
velocity dispersion and Balmer emission line luminosity (L-sigma relation)
reproduces the correlation for disk giant HII regions albeit with a larger
scatter. The scatter in the L-sigma relation is considerably reduced when
theoretical evolutionary corrections are applied suggesting that an age range
is present in the sample of CNSFRs. To analyse the observed complex profiles,
we performed multiple Gaussian component fits to the Hbeta and [OIII]?5007A
lines obtaining optimal fits with two Gaussians of different width. These best
fits indicate that the narrower component has average velocity dispersion close
to 23km/s while the broader component shows average values in the range
50-60km/s for both lines, close to the observed stellar velocity dispersions.
The fluxes of the broad and narrow Hbeta components are similar. This is not
the case for [OIII]5007A for which the broad components have higher fluxes than
the narrow ones, thus producing a clear segregation in their [OIII]/Hbeta
ratios. We suggest a possible scenario for understanding the behaviour of
CNSFRs in the L-sigma and sigma_gas-sigma_star diagrams involving an inner
gaseous disk responsible for the narrow component of the emission lines.Comment: 14 pages, 10 figures, accepted by MNRA
Burchnall-Chaundy polynomials for matrix ODOs and Picard-Vessiot Theory
Burchnall and Chaundy showed that if two ODOs , with analytic
coefficients commute there exists a polynomial with complex
coefficients such that , called the BC-polynomial. This polynomial
can be computed using the differential resultant for ODOs. In this work we
extend this result to matrix ordinary differential operators, MODOs. Matrices
have entries in a differential field , whose field of constants is
algebraically closed and of zero characteristic. We restrict to the case of
order one operators , with invertible leading coefficient. A new
differential elimination tool is defined, the matrix differential resultant. It
is used to compute the BC-polynomial of a pair of commuting MODOs and
proved to have constant coefficients. This resultant provides the necessary and
sufficient condition for the spectral problem to
have a solution. Techniques from differential algebra and Picard-Vessiot theory
allow us to describe explicitly isomorphisms between commutative rings of MODOs
and a finite product of rings of irreducible algebraic curves
Chemical Oxygen Demand Reduction Using the algae Dunaliella primolecta and Chlorella vulgaris
Farm industry wastewater is characterized by high organic materials and by high chemical oxygen demand (COD). Farms with large livestock and poultry operations can be a major source of wastewater thus a major concern for effective environmental and industrial management. Effective environmental and industrial management are high in cost therefor biofuels produced from plants have a potential of replacing a portion of fossil fuel consumption with a renewable efficient alternative. Due to California’s water crisis in the recent years, it is questioned if a biological treatment system that uses algal growth to create renewable energy in the form of biodiesel is able to remove polluting nutrients and greenhouse gases from dairy wastewater
Canopy structural attributes derived from AVIRIS imaging spectroscopy data in a mixed broadleaf/conifer forest
There is a well-established need within the remote sensing community for improved estimation and understanding of canopy structure and its influence on the retrieval of leaf biochemical properties. The main goal of this research was to assess the potential of optical spectral information from NASA's Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) to discriminate different canopy structural types. In the first phase, we assessed the relationships between optical metrics and canopy structural parameters obtained from LiDAR in terms of different canopy structural attributes (biomass (i.e., area under Vegetation Vertical Profile, VVPint), canopy height and vegetation complexity). Secondly, we identified and classified different âcanopy structural typesâ by integrating several structural traits using Random Forests (RF). The study area is a heterogeneous forest in Sierra National Forest in California (USA). AVIRIS optical properties were analyzed by means of several sets of variables, including single narrow band reflectance and 1st derivative, sub-pixel cover fractions, narrow-band indices, spectral absorption features, optimized normalized difference indices and Principal Component Analysis (PCA) components. Our results demonstrate that optical data contain structural information that can be retrieved. The first principal component, used as a proxy for albedo, was the most strongly correlated optical metric with vegetation complexity, and it also correlated well with biomass (VVPint) and height. In conifer forests, the shade fraction was especially correlated to vegetation complexity, while water-sensitive optical metrics had high correlations with biomass (VVPint). Single spectral band analysis results showed that correlations differ in magnitude and in direction, across the spectrum and by vegetation type and structural variable. This research illustrates the potential of AVIRIS to analyze canopy structure and to distinguish several structural types in a heterogeneous forest. Furthermore, RF using optical metrics derived from AVIRIS proved to be a powerful technique to generate maps of structural attributes. The results emphasize the importance of using the whole optical spectrum, since all spectral regions contributed to canopy structure assessment
A Rhizobium leguminosarum CHDL- (Cadherin-Like-) Lectin Participates in Assembly and Remodeling of the Biofilm Matrix
In natural environments most bacteria live in multicellular structures called biofilms. These cell aggregates are enclosed in a self-produced polymeric extracellular matrix, which protects the cells, provides mechanical stability and mediates cellular cohesion and adhesion to surfaces. Although important advances were made in the identification of the genetic and extracellular factors required for biofilm formation, the mechanisms leading to biofilm matrix assembly, and the roles of extracellular proteins in these processes are still poorly understood. The symbiont Rhizobium leguminosarum requires the synthesis of the acidic exopolysaccharide and the PrsDE secretion system to develop a mature biofilm. PrsDE is responsible for the secretion of the Rap family of proteins that share one or two Ra/CHDL (cadherin-like-) domains. RapA2 is a calcium-dependent lectin with a cadherin-like β sheet structure that specifically recognizes the exopolysaccharide, either as a capsular polysaccharide (CPS) or in its released form [extracellular polysaccharide (EPS)]. In this study, using gain and loss of function approaches combined with phenotypic and microscopic studies we demonstrated that RapA lectins are involved in biofilm matrix development and cellular cohesion. While the absence of any RapA protein increased the compactness of bacterial aggregates, high levels of RapA1 expanded distances between cells and favored the production of a dense matrix network. Whereas endogenous RapA(s) are predominantly located at one bacterial pole, we found that under overproduction conditions, RapA1 surrounded the cell in a way that was reminiscent of the capsule. Accordingly, polysaccharide analyses showed that the RapA lectins promote CPS formation at the expense of lower EPS production. Besides, polysaccharide analysis suggests that RapA modulates the EPS size profile. Collectively, these results show that the interaction of RapA lectins with the polysaccharide is involved in rhizobial biofilm matrix assembly and remodeling.Fil: Vozza, Nicolas Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Abdian, Patricia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Russo, Daniela Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Mongiardini, Elias Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Lodeiro, Anibal. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Biotecnología y Biología Molecular. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Biotecnología y Biología Molecular; ArgentinaFil: Molin, Soren. Technical University of Denmark; DinamarcaFil: Zorreguieta, Ángeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentin
Report on productivity in relation to housing conditions and community facilities in Hambaek, Korea
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