518 research outputs found
An efficient method for DNA extraction from Cladosporioid fungi
We developed an efficient method for DNA extraction from Cladosporioid fungi, which are important fungal plant pathogens. The cell wall of Cladosporioid fungi is often melanized, which makes it difficult to extract DNA from their cells. In order to overcome this we grew these fungi for three days on agar plates and extracted DNA from mycelium mats after manual or electric homogenization. High-quality DNA was isolated, with an A260/A280 ratio ranging between 1.6 and 2.0. Isolated genomic DNA was efficiently digested with restriction enzymes and produced distinct banding patterns on agarose gels for the different Cladosporium species. Clear DNA fragments from the isolated DNA were amplified by PCR using small and large subunit rDNA primers, demonstrating that this method provides DNA of sufficiently high quality for molecular analyse
Modelling Entrepreneurship
Two approaches can be distinguished with respect to modelling entrepreneurship: (i) the approach focusing on the net development of the number of entrepreneurs in an equilibrium framework and (ii) the approach focusing on the entries and exits of entrepreneurs. In this paper we unify these ap- proaches to arrive at a model explaining the equilibrium and actual number of entrepreneurs and the entry and exit rate of entrepreneurs simultaneously and consistently. We apply our unified approach to the Netherlands using self-employment data for the 1960-99 period. We find error-correction of about 20% per year and a very different situation in terms of disequilibrium before and after the early 1980's. Periods of high unemployment appear to be characterized by both high entry and high exit rates
Gene expression patterns in anterior pituitary associated with quantitative measure of oestrous behaviour in dairy cows
Intensive selection for high milk yield in dairy cows has raised production levels substantially but at the cost of reduced fertility, which manifests in different ways including reduced expression of oestrous behaviour. The genomic regulation of oestrous behaviour in bovines remains largely unknown. Here, we aimed to identify and study those genes that were associated with oestrous behaviour among genes expressed in the bovine anterior pituitary either at the start of oestrous cycle or at the mid-cycle (around day 12 of cycle), or regardless of the phase of cycle. Oestrous behaviour was recorded in each of 28 primiparous cows from 30 days in milk onwards till the day of their sacrifice (between 77 and 139 days in milk) and quantified as heat scores. An average heat score value was calculated for each cow from heat scores observed during consecutive oestrous cycles excluding the cycle on the day of sacrifice. A microarray experiment was designed to measure gene expression in the anterior pituitary of these cows, 14 of which were sacrificed at the start of oestrous cycle (day 0) and 14 around day 12 of cycle (day 12). Gene expression was modelled as a function of the orthogonally transformed average heat score values using a Bayesian hierarchical mixed model on data from day 0 cows alone (analysis 1), day 12 cows alone (analysis 2) and the combined data from day 0 and day 12 cows (analysis 3). Genes whose expression patterns showed significant linear or non-linear relationships with average heat scores were identified in all three analyses (177, 142 and 118 genes, respectively). Gene ontology terms enriched among genes identified in analysis 1 revealed processes associated with expression of oestrous behaviour whereas the terms enriched among genes identified in analysis 2 and 3 were general processes which may facilitate proper expression of oestrous behaviour at the subsequent oestrus. Studying these genes will help to improve our understanding of the genomic regulation of oestrous behaviour, ultimately leading to better management strategies and tools to improve or monitor reproductive performance in bovines
Geometric Second Order Field Equations for General Tensor Gauge Fields
Higher spin tensor gauge fields have natural gauge-invariant field equations
written in terms of generalised curvatures, but these are typically of higher
than second order in derivatives. We construct geometric second order field
equations and actions for general higher spin boson fields, and first order
ones for fermions, which are non-local but which become local on gauge-fixing,
or on introducing auxiliary fields. This generalises the results of Francia and
Sagnotti to all representations of the Lorentz group.Comment: 34 pages, LaTeX. Reference adde
Higher-Spin Matter Interactions in 2+1 Dimensions
We describe a model of massive matter fields interacting through higher-spin
gauge fields in 2+1 dimensional space-time. The two main conclusions are that
the parameter of mass appears as a module characterizing an appropriate
vacuum solution of the full non-linear model and that affects a structure
of a global vacuum higher-spin symmetry which leaves invariant the chosen
vacuum solution.Comment: LaTex, 9 pages, no figures, Invited talk at the 10 International
Conference Problems of Quantum Field Theory, Alushta (Cremea - Ukrain), May
13-18, 199
Superfield Theories in Tensorial Superspaces and the Dynamics of Higher Spin Fields
We present the superfield generalization of free higher spin equations in
tensorial superspaces and analyze tensorial supergravities with GL(n) and SL(n)
holonomy as a possible framework for the construction of a non-linear higher
spin field theory. Surprisingly enough, we find that the most general solution
of the supergravity constraints is given by a class of superconformally flat
and OSp(1|n)-related geometries. Because of the conformal symmetry of the
supergravity constraints and of the higher spin field equations such geometries
turn out to be trivial in the sense that they cannot generate a `minimal'
coupling of higher spin fields to their potentials even in curved backgrounds
with a non-zero cosmological constant. This suggests that the construction of
interacting higher spin theories in this framework might require an extension
of the tensorial superspace with additional coordinates such as twistor-like
spinor variables which are used to construct the OSp(1|2n) invariant
(`preonic') superparticle action in tensorial superspace.Comment: LaTeX, 30 pages, no figures. V2. Discussion on conventional
constraints extended, typos corrected, JHEP style, to appear in JHE
Higher-Spin Gauge Interactions for Massive Matter Fields in 3D AdS Space-Time
A remarkable feature of the models with interactions exhibiting higher-spin
(HS) gauge symmetries in is that their most symmetric vacua require
(anti)-de Sitter (AdS) geometry rather than the flat one. In striking
parallelism to what might be expected of M theory HS gauge theories describe
infinite towers of fields of all spins and possess naturally space-time SUSY
and Chan-Paton type inner symmetries. In this paper, we analyze at the level of
the equations of motion the simplest non-trivial HS model which describes HS
gauge interactions (on the top of the usual supergravitational and
(Chern-Simons) Yang-Mills interactions) of massive spin-0 and spin-1/2 matter
fields in d=2+1 AdS space-time. The parameter of mass of the matter fields is
identified with the vev of a certain auxiliary field in the model. The matter
fields are shown to be arranged into d3 N=2 massive hypermultiplets in certain
representations of Yang-Mills gauge groups. Discrete
symmetries of the full system are studied, and the related N=1 supersymmetric
truncations with O(n) and Sp(n) Yang-Mills symmetries are constructed. The
simplicity of the model allows us to elucidate some general properties of the
HS models. In particular, a new result, which can have interesting implications
to the higher-dimensional models, is that our model is shown to admit an
"integrating" flow that proves existence of a non-local B\"acklund-Nicolai-type
mapping to the free system.Comment: LaTeX, 46 pages, no figures; minor corrections, typo
Exploring Outcomes to Consider in Economic Evaluations of Health Promotion Programs: What Broader Non-Health Outcomes Matter Most?
Background
Attention is increasing on the consideration of broader non-health outcomes in economic evaluations. It is unknown which non-health outcomes are valued as most relevant in the context of health promotion. The present study fills this gap by investigating the relative importance of non-health outcomes in a health promotion context.
Method
We investigated the relative importance of ten non-health outcomes of health promotion programs not commonly captured in QALYs. Preferences were elicited from a sample of the Dutch general public (N = 549) by means of a ranking task. These preferences were analyzed using Borda scores and rank-ordered logit models.
Results
The relative order of preference (from most to least important) was: self-confidence, insights into own (un)healthy behavior, perceived life control, knowledge about a certain health problem, social support, relaxation, better educational achievements, increased labor participation and work productivity, social participation, and a reduction in criminal behavior. The weight given to a particular non-health outcome was affected by the demographic variables age, gender, income, and education. Furthermore, in an open question, respondents mentioned a number of other relevant non-health outcomes, which we classified into outcomes relevant for the individual, the direct social environment, and for society as a whole.
Conclusion
The study provides valuable insights in the non-health outcomes that are considered as most important by the Dutch general population. Ideally, researchers should include the most important non-health outcomes in economic evaluations of health promotio
Nonlinear Equations for Symmetric Massless Higher Spin Fields in
Nonlinear field equations for totally symmetric bosonic massless fields of
all spins in any dimension are presented.Comment: 19 pages, latex, no figures, v2 minor correction
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