590 research outputs found
Activities of \gamma-ray emitting isotopes in rainwater from Greater Sudbury, Canada following the Fukushima incident
We report the activity measured in rainwater samples collected in the Greater
Sudbury area of eastern Canada on 3, 16, 20, and 26 April 2011. The samples
were gamma-ray counted in a germanium detector and the isotopes 131I and 137Cs,
produced by the fission of 235U, and 134Cs, produced by neutron capture on
133Cs, were observed at elevated levels compared to a reference sample of
ice-water. These elevated activities are ascribed to the accident at the
Fukushima Dai-ichi nuclear reactor complex in Japan that followed the 11 March
earthquake and tsunami. The activity levels observed at no time presented
health concerns.Comment: 4 pages, 8 figure
Comparation of the new rebound tonometer IOPen and the Goldmann tonometer, and their relationship to corneal properties
Purpose To compare the intraocular pressures
(IOPs) obtained with the IOPen rebound
tonometer, Goldmann applanation tonometer
(GAT) and the ocular response analyzer (ORA)
and investigate the effects of corneal
biomechanical properties on IOPen
measurements.
Methods A total of 198 normal eyes were
included in this cross-sectional and
randomized study. Three measurements were
taken using IOPen. Agreement between
tonometers was calculated using the Bland
and Altman limits of agreement (LoA)
analysis.
Results The median IOPen IOP was 3mmHg
below the GAT (Po0.001), 3mmHg below
the ORA IOP similar to Goldmann (IOPg),
and 3mmHg below the ORA IOP corrected
using corneal parameters (IOPcc)(Po0.01).
The LoA width between the IOPen and GAT
IOPs varied between 13.92 (mean IOPen IOP)
and 15.99mmHg (third IOPen measurement).
The central corneal thickness (CCT) was
unrelated to IOPen measurements (P40.05).
Corneal hysteresis (CH) and corneal rigidity
factor (CRF) were correlated with IOPen
and GAT.
Conclusions IOPen underestimated the IOP
compared with GAT and ORA. The effect of
measurement quality or measurement order on
IOPen was low. CCT did not affect the IOPen,
but the CH and CRF did. The LoA width
between the IOPen and GAT IOPs was higher
than between the ORA IOPg or ORA IOPcc
and GAT IOPs
Signatures of electron correlations in the transport properties of quantum dots
The transition matrix elements between the correlated and
electron states of a quantum dot are calculated by numerical diagonalization.
They are the central ingredient for the linear and non--linear transport
properties which we compute using a rate equation. The experimentally observed
variations in the heights of the linear conductance peaks can be explained. The
knowledge of the matrix elements as well as the stationary populations of the
states allows to assign the features observed in the non--linear transport
spectroscopy to certain transition and contains valuable information about the
correlated electron states.Comment: 4 pages (revtex,27kB) + 3 figures in one file ziped and uuencoded
(postscript,33kB), to appear in Phys.Rev.B as Rapid Communicatio
Effect of oxygen plasma etching on graphene studied with Raman spectroscopy and electronic transport
We report a study of graphene and graphene field effect devices after
exposure to a series of short pulses of oxygen plasma. We present data from
Raman spectroscopy, back-gated field-effect and magneto-transport measurements.
The intensity ratio between Raman "D" and "G" peaks, I(D)/I(G) (commonly used
to characterize disorder in graphene) is observed to increase approximately
linearly with the number (N(e)) of plasma etching pulses initially, but then
decreases at higher Ne. We also discuss implications of our data for extracting
graphene crystalline domain sizes from I(D)/I(G). At the highest Ne measured,
the "2D" peak is found to be nearly suppressed while the "D" peak is still
prominent. Electronic transport measurements in plasma-etched graphene show an
up-shifting of the Dirac point, indicating hole doping. We also characterize
mobility, quantum Hall states, weak localization and various scattering lengths
in a moderately etched sample. Our findings are valuable for understanding the
effects of plasma etching on graphene and the physics of disordered graphene
through artificially generated defects.Comment: 10 pages, 5 figure
Harvest index, a parameter conditioning responsiveness of wheat plants to elevated CO2
The expansion of the world’s population requires the development of high production agriculture. For this purpose, it is essential to identify target points conditioning crop responsiveness to predicted [CO2]. The aim of this study was to determine the relevance of ear sink strength in leaf protein and metabolomic profiles and its implications in photosynthetic activity and yield of durum wheat plants exposed to elevated [CO2]. For this purpose, a genotype with high harvest index (HI) (Triticum durum var. Sula) and another with low HI (Triticum durum var. Blanqueta) were exposed to elevated [CO2] (700 µmol mol–1 versus 400 µmol mol–1 CO2) in CO2 greenhouses. The obtained data highlighted that elevated [CO2] only increased plant growth in the genotype with the largest HI; Sula. Gas exchange analyses revealed that although exposure to 700 µmol mol–1 depleted Rubisco content, Sula was capable of increasing the light-saturated rate of CO2 assimilation (Asat) whereas, in Blanqueta, the carbohydrate imbalance induced the down-regulation of Asat. The specific depletion of Rubisco in both genotypes under elevated [CO2], together with the enhancement of other proteins in the Calvin cycle, revealed that there was a redistribution of N from Rubisco towards RuBP regeneration. Moreover, the down-regulation of N, NO3 –, amino acid, and organic acid content, together with the depletion of proteins involved in amino acid synthesis that was detected in Blanqueta grown at 700 µmol mol–1 CO2, revealed that inhibition of N assimilation was involved in the carbohydrate imbalance and consequently with the down-regulation of photosynthesis and growth in these plants
SCOR Model for a Dual-Channel Supply Chain using Drop Shipping to Reduce Overstock in Small- and Medium-Sized Retail Enterprises
Sales are central to retail companies. One of the main problems for these companies is when products are sold later than expected, causing overstock due to lower inventory turnover, which increases inventory levels. Therefore, for many retailers, it is important to solve this problem. This is mostly applicable to companies engaged in sales; however, if we take into account the main supplier and the way they act within the supply chain, we must also consider an additional approach. Since online sales are a major innovation brought about by the new digital era, it is standard for sales strategies to focus on this new requirement of customers. In this way, the main supplier takes a leap forward on Internet sales, creating another sales channel. This is when companies under the supply chain start losing sales. According to the above, a dual supply chain model was suggested using the SCOR model and drop shipping. After the improvement proposal was implemented, the company reported a reduction of approximately S/13,000 when comparing the first quarter of 2018 to that of 2019
Effect of a diet supplemented with sphingomyelin and probiotics on colon cancer development in mice
Previous studies have reported that dietary sphingomyelin could inhibit early stages of colon cancer. Lactic acid–producing bacteria have also been associated with an amelioration of cancer symptoms. However, little is known about the potential beneficial effects of the combined administration of both sphingomyelin and lactic acid–producing bacteria. This article analyzes the effect of a diet supplemented with a combination of the probiotics Lacticaseibacillus casei and Bifidobacterium bifidum (108 CFU/ml) and sphingomyelin (0.05%) on mice with 1,2-dimethylhydrazine (DMH)-induced colon cancer. Thirty-six BALB/c mice were divided into 3 groups: one healthy group (group C) and two groups with DMH-induced cancer, one fed a standard diet (group D) and the other fed a diet supplemented with sphingomyelin and probiotics (DS). The number of aberrant crypt foci, marker of colon cancer development, was lower in the DS. The dietary supplementation with the synbiotic reversed the cancer-induced impairment of galactose uptake in enterocyte brush–border–membrane vesicles. These results confirm the beneficial effects of the synbiotic on the intestinal physiology of colon cancer mice and contribute to the understanding of the possible mechanisms involved.This study was supported by the Government of Spain grant number AGL 2006–1029-C02-01/ALI, CIBER (CB12/03/30002) and the Department of Innovation, Business and Employment of the Government of Navarra (Spain)
Effect of antihistamine up-dosing in chronic urticaria
Chronic urticaria has an important impact upon patient quality of life, and no treatment has yet been developed capable of effectively
controlling the disease. The most recent guidelines recommend the use of non-sedating antihistamines at high doses as second-step
therapy before resorting to other treatments. The present review examines the studies published to date on the use of H1 antihistamines
at doses higher than those indicated as therapeutic doses in chronic urticaria. Most of the studies report no significant differences among
the studied doses – only a tendency towards increased response on elevating the dose.There are no clinically well designed, randomized
double-blind trials comparing efficacy between therapeutic doses and doses higher than those indicated in the corresponding Summary
of Product Characteristics. Likewise, there are insufficient data to conduct a meta-analysis and thus classify the degree of evidence of the
few available studies, which moreover present contradictory results. At present, the prescription of high-dose H1 antihistamines is based
only on experts opinion. However, considering the high safety profile of these drugs, it would be a good option to evaluate their efficacy
at high doses, before moving on to other therapeutic steps
Molecular diagnosis in Allergology: application of the microarray tecnique
Recombinant and purified allergens are currently available for determining
specific IgE targeted to different allergenic components. In this way it is
possible to diagnose the sensitization profile of each individual patient. The
microarray technique makes it possible to determine specific IgE against multiple
allergens simultaneously in one same patient, with a minimum amount of serum, and
even allows the determination of IgG and IgM against the same allergens in one
same serum sample. Microarray procedures are being developed not only for the
determination of antibodies but also for cell activation tests. In addition,
microarray technology will help explain cross-reactions, and will facilitate the
evaluation of subjects in which skin tests cannot be performed. These techniques
will allow a great step forward in the development of immunotherapy specifically
targeted to the sensitizations found in each individual patient, yielding
especially hypoallergenic forms of great immunogenic capacity, and thus improving
the safety and efficacy of immunotherapy. Lastly, microarrays will improve our
understanding of the physiopathology of allergic diseases
Correlations between Ground and Excited State Spectra of a Quantum Dot
We have studied the ground and excited state spectra of a semiconductor
quantum dot for successive numbers of electron occupancy using linear and
nonlinear magnetoconductance measurements. We present the first observation of
direct correlation between the mth excited state of the N electron system and
the ground state of the N+m electron system for m up to 4. Results are
consistent with a non-spin-degenerate single particle picture of the filling of
levels. Electron-electron interaction effects are also observed as a
perturbation to this model. Magnetoconductance fluctuations of ground states
are shown as anticrossings where wavefunction characteristics are exchanged
between adjacent levels.Comment: 8 pages pdf; gzipped ps available at
http://www-leland.stanford.edu/group/MarcusLab/grouppubs.htm
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