57,717 research outputs found
Analysis of information use in agricultural science PhD theses at Central University of Venezuela
Purpose – To analyze information use in agricultural science PhD theses submitted between 1986 and 2002 in the Faculty of Agronomy, Central University of Venezuela (UCV).
Design/methodology/approach – The source of information was the UCV Faculty of Agronomy, Library's database, “Tesis”. The unidimensional production and use indicators analyzed included: scientific production, reference density, self-citations, document contemporaneousness and type of documents cited, reference scattering and accessibility of the journals cited.
Findings – The analysis of the data obtained from 4,646 bibliographic references in 42 agricultural science PhD theses provides insight into information use in a Venezuelan agricultural science community. The mean number of references per thesis found was 113?±?21. The number of women earning a PhD in agriculture was observed to grow. The percentage of self-citations varied widely. The half-life was 11 years and the Price's Index 22 per cent. According to the distribution by document type, most of the publications cited were articles in journals, while references to technical standards and internet publications were rare. UCV Faculty of Agronomy PhD students tended to seek information primarily in the Anglo Saxon literature. The Celestino Bonfanti Library periodicals section met a high proportion (92 per cent) of the demand for journals located in the first and second concentration-scattering zones.
Originality/value – This is the only paper on the evaluation of PhD theses in Venezuela. The findings will be useful for education planners in Venezuela and other developing countries.Publicad
Numerical performance of Penalized Comparison to Overfitting for multivariate kernel density estimation
Kernel density estimation is a well known method involving a smoothing
parameter (the bandwidth) that needs to be tuned by the user. Although this
method has been widely used the bandwidth selection remains a challenging issue
in terms of balancing algorithmic performance and statistical relevance. The
purpose of this paper is to compare a recently developped bandwidth selection
method for kernel density estimation to those which are commonly used by now
(at least those which are implemented in the R-package). This new method is
called Penalized Comparison to Overfitting (PCO). It has been proposed by some
of the authors of this paper in a previous work devoted to its statistical
relevance from a purely theoretical perspective. It is compared here to other
usual bandwidth selection methods for univariate and also multivariate kernel
density estimation on the basis of intensive simulation studies. In particular,
cross-validation and plug-in criteria are numerically investigated and compared
to PCO. The take home message is that PCO can outperform the classical methods
without algorithmic additionnal cost
On-site correlation in valence and core states of ferromagnetic nickel
We present a method which allows to include narrow-band correlation effects
into the description of both valence and core states and we apply it to the
prototypical case of nickel. The results of an ab-initio band calculation are
used as input mean-field eigenstates for the calculation of self-energy
corrections and spectral functions according to a three-body scattering
solution of a multi-orbital Hubbard hamiltonian. The calculated quasi-particle
spectra show a remarkable agreement with photoemission data in terms of band
width, exchange splitting, satellite energy position of valence states, spin
polarization of both the main line and the satellite of the 3p core level.Comment: 14 pages, 10 PostScript figures, RevTeX, submitted to PR
Determinants of inappropriate acute pain management in old people unable to communicate verbally in the emergency department
Objectives: Poor pain management is relevant among individuals unable to communicate verbally (UCV). Analgesia may be due to three determinants: patients' status, physician's characteristics and pain etiology. Our aim is to investigate the association between prescription of ED pain treatment and these determinants. Materials and Methods: An observational prospective study including UCV patients was conducted. Severity of pain was evaluated by ALGOPLUS Scale and a score P â¥Â 2 out of 5 on the pain scale was retained as the threshold for the presence of acute pain in elderly UCV patients. Results: Our data showed that only 31,9% of UCV patients received a pharmacological treatment. The presence of the caregiver would influence the rate of therapy administration [OR 6,19 (95% CI 2,6â14,75)]. The presence of leg pain [OR 0,32 (95% CI 0,12â0,86)] and head pain [OR 0,29 (95% CI 0,10â0,84)] were less likely associated to receive analgesia. Pain related to trauma [OR 4.82 (95% CI 1.17 to 19.78)] and youngest physicians [OR 1.08 (95% CI 1.001 to 1.18)] were variables associated with the administration of drugs opiates. Discussion: Older UCV patients presenting to the ED with pain are at high risk of inadequate analgesia. Providers should always suspect presence of pain and an increasing need for behavioural pain evaluation is necessary for a complete assessment. Conclusions: Presence of a caregiver influences a more appropriate pain management in these patients. Staff training on pain management could result in better assessment, treatment, and interaction with caregivers. Keywords: Emergency department, Pain, Oligoanalgesi
Unitarity in periodic potentials: a renormalization group analysis
We explore the universal properties of interacting fermionic lattice systems,
mostly focusing on the development of pairing correlations from attractive
interactions. Using renormalization group we identify a large number of fixed
points and show that they correspond to resonant scattering in multiple
channels. Pairing resonances in finite-density band insulators occur between
quasiparticles and quasiholes living at different symmetry-related wavevectors
in the Brillouin zone. This allows a BCS-BEC crossover interpretation of both
Cooper and particle-hole pairing. We show that in two dimensions the run-away
flows of relevant attractive interactions lead to charged-boson-dominated low
energy dynamics in the insulating states, and superfluid transitions in bosonic
mean-field or XY universality classes. Analogous phenomena in higher dimensions
are restricted to the strong coupling limit, while at weak couplings the
transition is in the pair-breaking BCS class. The models discussed here can be
realized with ultra-cold gases of alkali atoms tuned to a broad Feshbach
resonance in an optical lattice, enabling experimental studies of pairing
correlations in insulators, especially in their universal regimes. In turn,
these simple and tractable models capture the emergence of fluctuation-driven
superconducting transitions in fermionic systems, which is of interest in the
context of high temperature superconductors.Comment: 16 pages, 6 figures, published versio
Old Wine In A New Bottle? Proposed Sugar Industry Restructuring and Land Conflict in Fiji
The proposed restructure of Fiji's sugar industry has the potential to change fundamentally the incentives facing stakeholders and their interaction. How well the stated objective of 'unity in purpose' is achieved will depend on whether the causes of th
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