1,512 research outputs found
Process transparency on construction sites : examples from construction companies in Brazil
Process transparency is the core concept in Visual Management (VM), which is one of the founding blocks of the Toyota Production System. This paper presents the
preliminary results of a collaborative research conducted between Brazil and the UK, as part of a research effort focused on the application of Visual Management in
construction. How process transparency is realized on construction sites is the main research question of the paper. The use of this concept and the implementation of the
transparency theory were investigated through multiple case studies, carried out in nine different construction companies. The findings are explained through six theoretical transparency increasing approaches. The affecting parameters in the application of, the management’s perception of and several methods in process
transparency in construction were identified. Further work, especially exploring the functions of process transparency on construction sites and reflecting the worker perception of the issue, is necessary to elaborate the process transparency concept
Composition and evaluation of the lethality of Lippia gracilis essential oil to adults of Biomphalaria glabrata and larvae of Artemia salina
Lippia gracilis essential oil (LGEO) was evaluated for its molluscicidal activity against Biomphalaria glabrata and toxicity to brine shrimps (Artemia salina). L. gracilis was collected from the city Tomar do Gerú- Sergipe, Brazil. The LGEO were characterized by gas chromatography-mass spectrometry (GC/MS). The values of LC10, LC50 and LC90 were respectively 36.9, 62.2 and 82.8 ppm for B. glabrata and 19.6, 23.6 and 26.1 ppm for A. salina. GC/MS analysis showed a total volatile content of 98.6% in the LGEO. The major components were identified as thymol (24.0%), p-cymene (15.9%), methyl-thymol (11.7%), γ-terpinene (10.9%) and β-caryophyllene (7.8%).Keywords: Chemical composition, Lippia species, molluscicidal activity, Verbenacea
Magnetic Fluffy Dark Matter
We explore extensions of inelastic Dark Matter and Magnetic inelastic Dark
Matter where the WIMP can scatter to a tower of heavier states. We assume a
WIMP mass GeV and a constant splitting between
successive states keV. For the
spin-independent scattering scenario we find that the direct experiments CDMS
and XENON strongly constrain most of the DAMA/LIBRA preferred parameter space,
while for WIMPs that interact with nuclei via their magnetic moment a region of
parameter space corresponding to GeV and keV
is allowed by all the present direct detection constraints.Comment: 16 pages, 6 figures, added comments about magnetic moment form factor
to Sec 3.1.2 and results to Sec 3.2.2, final version to be published in JHE
Volatile constituents and behavioral change induced by Cymbopogon winterianus leaf essential oil in rodents
Cymbopogon winterianus Jowitt (‘Java citronella’) is an important essential oil yielding aromatic grass cultivated in India and Brazil and its volatile essential oils extracted from its leaves are used in perfumery, cosmetics, pharmaceuticals and flavoring industries. However, there is no report on any psychopharmacological study of C. winterianus leaf essential oil (LEO) available to date. In this study, the pharmacological effects of the LEO were investigated in animal models and its phytochemical analyses. GC-MS analysis showed a mixture of monoterpenes, as citronellal (36.19%), geraniol (32.82%) and citronellol (11.37%). LEO exhibited an inhibitory effect on the locomotor activity of mice, an antinociceptive effect by increasing the reaction time in the writhing and capsaicin tests. All doses induced a significant increase in the sleeping time of animals not having modified however, the latency. The LEO did not alter the remaining time of the animals on the rota-rod apparatus. These results suggest a possible central effect.Key words: Cymbopogon winterianus, essential oil, CNS, behavioral effects, analgesic
Controlling Cherenkov angles with resonance transition radiation
Cherenkov radiation provides a valuable way to identify high energy particles
in a wide momentum range, through the relation between the particle velocity
and the Cherenkov angle. However, since the Cherenkov angle depends only on
material's permittivity, the material unavoidably sets a fundamental limit to
the momentum coverage and sensitivity of Cherenkov detectors. For example, Ring
Imaging Cherenkov detectors must employ materials transparent to the frequency
of interest as well as possessing permittivities close to unity to identify
particles in the multi GeV range, and thus are often limited to large gas
chambers. It would be extremely important albeit challenging to lift this
fundamental limit and control Cherenkov angles as preferred. Here we propose a
new mechanism that uses constructive interference of resonance transition
radiation from photonic crystals to generate both forward and backward
Cherenkov radiation. This mechanism can control Cherenkov angles in a flexible
way with high sensitivity to any desired range of velocities. Photonic crystals
thus overcome the severe material limit for Cherenkov detectors, enabling the
use of transparent materials with arbitrary values of permittivity, and provide
a promising option suited for identification of particles at high energy with
enhanced sensitivity.Comment: There are 16 pages and 4 figures for the manuscript. Supplementary
information with 18 pages and 5 figures, appended at the end of the file with
the manuscript. Source files in Word format converted to PDF. Submitted to
Nature Physic
LHC Coverage of RPV MSSM with Light Stops
We examine the sensitivity of recent LHC searches to signatures of
supersymmetry with R-parity violation (RPV). Motivated by naturalness of the
Higgs potential, which would favor light third-generation squarks, and the
stringent LHC bounds on spectra in which the gluino or first and second
generation squarks are light, we focus on scenarios dominated by the pair
production of light stops. We consider the various possible direct and cascade
decays of the stop that involve the trilinear RPV operators. We find that in
many cases, the existing searches exclude stops in the natural mass range and
beyond. However, typically there is little or no sensitivity to cases dominated
by UDD operators or LQD operators involving taus. We propose several ideas for
searches which could address the existing gaps in experimental coverage of
these signals.Comment: 41 pages, 12 figures; v2: included new searches (see footnote 10),
minor corrections and improvement
Oatmeal particle size alters glycemic index but not as a function of gastric emptying rate
The aim of this study was to determine the extent to which oat particle size in a porridge could alter glucose absorption, gastric emptying, gastrointestinal hormone response, and subjective feelings of appetite and satiety. Porridge was prepared from either oat flakes or oat flour with the same protein, fat, carbohydrate, and mass. These were fed to eight volunteers on separate days in a crossover study, and subjective appetite ratings, gastric contents, and plasma glucose, insulin, and gastrointestinal hormones were determined over a period of 3 h. The flake porridge gave a lower glucose response than the flour porridge, and there were apparent differences in gastric emptying in both the early and late postprandial phases. The appetite ratings showed similar differences between early- and late-phase behavior. The structure of the oat flakes remained sufficiently intact to delay their gastric emptying, leading to a lower glycemic response, even though initial gastric emptying rates were similar for the flake and flour porridge. This highlights the need to take food structure into account when considering relatively simple physiological measures and offering nutritional guidance
Interactions of Candida albicans with host epithelial surfaces
Candida albicans is an opportunistic, fungal pathogen of humans that frequently causes superficial infections
of oral and vaginal mucosal surfaces of debilitated and susceptible individuals. The organism is however,
commonly encountered as a commensal in healthy individuals where it is a component of the normal
microflora. The key determinant in the type of relationship that Candida has with its host is how it interacts
with the epithelial surface it colonises. A delicate balance clearly exists between the potentially damaging
effects of Candida virulence factors and the nature of the immune response elicited by the host. Frequently, it
is changes in host factors that lead to Candida seemingly changing from a commensal to pathogenic existence.
However, given the often reported heterogeneity in morphological and biochemical factors that exist between
Candida species and indeed strains of C. albicans, it may also be the fact that colonising strains differ in the
way they exploit resources to allow persistence at mucosal surfaces and as a consequence this too may affect
the way Candida interacts with epithelial cells. The aim of this review is to provide an overview of some of the
possible interactions that may occur between C. albicans and host epithelial surfaces that may in turn dictate
whether Candida removal, its commensal persistence or infection follows
MFV Reductions of MSSM Parameter Space
The 100+ free parameters of the minimal supersymmetric standard model (MSSM)
make it computationally difficult to compare systematically with data,
motivating the study of specific parameter reductions such as the cMSSM and
pMSSM. Here we instead study the reductions of parameter space implied by using
minimal flavour violation (MFV) to organise the R-parity conserving MSSM, with
a view towards systematically building in constraints on flavour-violating
physics. Within this framework the space of parameters is reduced by expanding
soft supersymmetry-breaking terms in powers of the Cabibbo angle, leading to a
24-, 30- or 42-parameter framework (which we call MSSM-24, MSSM-30, and MSSM-42
respectively), depending on the order kept in the expansion. We provide a
Bayesian global fit to data of the MSSM-30 parameter set to show that this is
manageable with current tools. We compare the MFV reductions to the
19-parameter pMSSM choice and show that the pMSSM is not contained as a subset.
The MSSM-30 analysis favours a relatively lighter TeV-scale pseudoscalar Higgs
boson and with multi-TeV sparticles.Comment: 2nd version, minor comments and references added, accepted for
publication in JHE
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