208 research outputs found
Utilization of image analysis for description of drying characteristics of selected tropical fruits
ArticleThis study is focused on the utilization of image analysis for description of dimensions,
and colours changes of fruits during drying process. Selected tropical fruits such are banana
(Musa acuminata), mango (Magnifera indica) and pineapple (Ananas comosus) originally from
North Sumatera in Indonesia were used in this experiment. Sliced pieces of the fruits were dried
in experimental oven under temperature 90 °C for period of time 180 min and image of fruits
samples were recorded by digital camera with HD resolution continuously throughout drying
process. With aid of image analysis using Image J software and regarding to drying characteristics
the colours and dimensions of the samples were analysed
Mutational pathway determines whether drug gradients accelerate evolution of drug-resistant cells
Drug gradients are believed to play an important role in the evolution of
bacteria resistant to antibiotics and tumors resistant to anti-cancer drugs. We
use a statistical physics model to study the evolution of a population of
malignant cells exposed to drug gradients, where drug resistance emerges via a
mutational pathway involving multiple mutations. We show that a non-uniform
drug distribution has the potential to accelerate the emergence of resistance
when the mutational pathway involves a long sequence of mutants with increasing
resistance, but if the pathway is short or crosses a fitness valley, the
evolution of resistance may actually be slowed down by drug gradients. These
predictions can be verified experimentally, and may help to improve strategies
for combatting the emergence of resistance.Comment: 6 pages, 3 figures, final version before acceptance to Phys. Rev.
Letters. P.G and B.W contributed equally to this wor
First results of material charging in the space environment
A satellite experiment, designed to measure potential charging of typical thermal control materials at near geosynchronous altitude, was flown as part of the SCATHA program. Direct observations of charging of typical satellite materials in a natural charging event ( 5 keV) are presented. The results show some features which differ significantly from previous laboratory simulations of the environment
Analysis of the Thermal and Magnetic Properties of Amorphous Fe 61Co10Zr2.5Hf2.5Me2W2B20 (Where Me = Mo, Nb, Ni Or Y) Ribbons
The paper presents the results of structural and magnetic properties and thermal stability for a group of functional materials based on Fe61Co10Zr2.5Hf2.5Me2W2B20 (where Me = Mo, Nb, Ni or Y). Samples were obtained in the form of ribbons using melt-spinning method. The X-ray diffraction patterns of investigated samples confirmed their amorphous structure. Based on the analysis of DSC curves characteristic temperatures: glass forming temperature (Tg), crystallization temperature (Tx) and temperature range of the supercooled liquid ΔTx were determined. Small addition of transition metals elements has strong influence on magnetic and thermal parameters of studied materials. The comprehensive studies revealed that in terms of magnetic properties the Ni-addition resulted in highest reduction in coercivity and anisotropy field
The S Matrix of 6D Super Yang-Mills and Maximal Supergravity from Rational Maps
We present new formulas for -particle tree-level scattering amplitudes of
six-dimensional super Yang-Mills (SYM) and
supergravity (SUGRA). They are written as integrals over
the moduli space of certain rational maps localized on the solutions
of the scattering equations. Due to the properties of spinor-helicity variables
in six dimensions, the even- and odd- formulas are quite different and
have to be treated separately. We first propose a manifestly supersymmetric
expression for the even- amplitudes of SYM theory and
perform various consistency checks. By considering soft-gluon limits of the
even- amplitudes, we deduce the form of the rational maps and the integrand
for odd. The odd- formulas obtained in this way have a new redundancy
that is intertwined with the usual invariance on the
Riemann sphere. We also propose an alternative form of the formulas, analogous
to the Witten-RSV formulation, and explore its relationship with the symplectic
(or Lagrangian) Grassmannian. Since the amplitudes are formulated in a way that
manifests double-copy properties, formulas for the six-dimensional
SUGRA amplitudes follow. These six-dimensional results
allow us to deduce new formulas for five-dimensional SYM and SUGRA amplitudes,
as well as massive amplitudes of four-dimensional SYM on the
Coulomb branch.Comment: 71+23 pages. v2: minor corrections, references added, matches
published JHEP versio
Should We Learn Probabilistic Models for Model Checking? A New Approach and An Empirical Study
Many automated system analysis techniques (e.g., model checking, model-based
testing) rely on first obtaining a model of the system under analysis. System
modeling is often done manually, which is often considered as a hindrance to
adopt model-based system analysis and development techniques. To overcome this
problem, researchers have proposed to automatically "learn" models based on
sample system executions and shown that the learned models can be useful
sometimes. There are however many questions to be answered. For instance, how
much shall we generalize from the observed samples and how fast would learning
converge? Or, would the analysis result based on the learned model be more
accurate than the estimation we could have obtained by sampling many system
executions within the same amount of time? In this work, we investigate
existing algorithms for learning probabilistic models for model checking,
propose an evolution-based approach for better controlling the degree of
generalization and conduct an empirical study in order to answer the questions.
One of our findings is that the effectiveness of learning may sometimes be
limited.Comment: 15 pages, plus 2 reference pages, accepted by FASE 2017 in ETAP
Statistical Inference for Valued-Edge Networks: Generalized Exponential Random Graph Models
Across the sciences, the statistical analysis of networks is central to the
production of knowledge on relational phenomena. Because of their ability to
model the structural generation of networks, exponential random graph models
are a ubiquitous means of analysis. However, they are limited by an inability
to model networks with valued edges. We solve this problem by introducing a
class of generalized exponential random graph models capable of modeling
networks whose edges are valued, thus greatly expanding the scope of networks
applied researchers can subject to statistical analysis
Characterization of crop residues from false banana/Ensete ventricosum/in Ethiopia in view of a full-resource valorization
Research ArticleFalse banana /Ensete ventricosum [Welw.] Cheesman/ is exploited as a food crop in
Ethiopia where it represents an important staple food. The plant is harvested and large
amounts of biomass residues are originated, mainly from the pseudo stem (i.e., fiber bundles
obtained from the leaf sheaths after being scrapped to produce starchy food) and the
inflorescence stalk. These materials were studied in relation to their summative chemical
composition, composition of lignin, lipophilic and polar extracts. Moreover, their structural
characteristics, in view of their valorization, were scrutinized. The analytical studies were
performed with the aid of FTIR, GC/MS, Py-GC/MS and SEM. The fiber bundles are aggregates
of mainly long and slender fibers with low ash, extractives and lignin contents (3.8%.
4.4% and 10.5% respectively) and high holocellulose and α-cellulose contents (87.5% and
59.6% respectively). The hemicelluloses in the fibers are mostly highly acetylated xylans
and the lignin is of the H-type (H:G:S, 1:0.7:0.8). This lignin composition is in line with the
FTIR peaks at 1670 cm-1 and 1250 cm-1.The inflorescence stalk has high ash content
(12.3% in the main stalk and 24.6% in fines) with a major proportion of potassium, high
extractives (25.9%), and low lignin and α-cellulose contents (5.8% and 17.9% respectively).
The stalk includes numerous starch granules in the cellular structure with the predominant
presence of parenchyma. The potential valorization routes for these materials are clearly different.
The fiber bundles could be used as a fiber source for paper pulp production with the
possibility of a prior hemicelluloses removal while the inflorescence stalk has nutritional
value for food and fodder. Furthermore, it can also be used for sugar fermentation productsinfo:eu-repo/semantics/publishedVersio
Aspirin and clonidine in non-cardiac surgery: acute kidney injury substudy protocol of the Perioperative Ischaemic Evaluation (POISE) 2 randomised controlled trial
Introduction: Perioperative Ischaemic Evaluation-2 (POISE-2) is an international 2×2 factorial randomised controlled trial of low-dose aspirin versus placebo and low-dose clonidine versus placebo in patients who undergo non-cardiac surgery. Perioperative aspirin (and possibly clonidine) may reduce the risk of postoperative acute kidney injury (AKI). Methods and analysis: After receipt of grant funding, serial postoperative serum creatinine measurements began to be recorded in consecutive patients enrolled at substudy participating centres. With respect to the study schedule, the last of over 6500 substudy patients from 82 centres in 21 countries were randomised in December 2013. The authors will use logistic regression to estimate the adjusted OR of AKI following surgery (compared with the preoperative serum creatinine value, a postoperative increase ≥26.5 μmol/L in the 2 days following surgery or an increase of ≥50% in the 7 days following surgery) comparing each intervention to placebo, and will report the adjusted relative risk reduction. Alternate definitions of AKI will also be considered, as will the outcome of AKI in subgroups defined by the presence of preoperative chronic kidney disease and preoperative chronic aspirin use. At the time of randomisation, a subpopulation agreed to a single measurement of serum creatinine between 3 and 12 months after surgery, and the authors will examine intervention effects on this outcome. Ethics and dissemination: The authors were competitively awarded a grant from the Canadian Institutes of Health Research for this POISE-2 AKI substudy. Ethics approval was obtained for additional kidney data collection in consecutive patients enrolled at participating centres, which first began for patients enrolled after January 2011. In patients who provided consent, the remaining longer term serum creatinine data will be collected throughout 2014. The results of this study will be reported no later than 2015.Amit X Garg ... Tom Painter ... et al. on behalf of the POISE-2 Investigator
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