1,848 research outputs found
Confinement interaction in nonlinear generalizations of the Wick-Cutkosky model
We consider nonlinear-mediating-field generalizations of the Wick-Cutkosky
model. Using an iterative approach and eliminating the mediating field by means
of the covariant Green function we arrive at a Lagrangian density containing
many-point time-nonlocal interaction terms. In low-order approximations of
theory we obtain the usual two-current interaction as well as
a three-current interaction of a confining type. The same result is obtained
without approximation for a version of the dipole model. The transition to the
Hamiltonian formalism and subsequent canonical quantization is performed with
time non-locality taken into account approximately.
A relativistic three-particle wave equation is derived variationally by using
a three-particle Fock space trial state. The non-relativistic limit of this
equation is obtained and its properties are analyzed and discussed.Comment: 15 pages, 1 figure, LaTe
Primary cutaneous CD4-positive small/medium-sized pleomorphic T-cell lymphoma following heart transplantation
Post-transplantation cutaneous lymphoproliferative diseases (PTCLD) are rare, with 29 cases
have so far been reported in the literature—only 4 cases underwent cardiac transplantation.
Herein, we report on, to the best of our knowledge, the first case in the English literature of primary
cutaneous CD4-positive small/medium-sized pleomorphic T-cell lymphoma in a cardiac
transplant recipient
Root development controls hotspots localization and temperature sensitivity of enzyme activity in the rhizosphere
The rhizosphere is a very important and dynamic hotspot of microbial activity in soil. Consequently, the enzyme activities in the rhizosphere are a footprint of complex plant-microbial interactions and may reflect functional response to climate changes.The temperature sensitivity of enzymes responsible for organic matter decomposition in soil is crucial for predicting the effects of global warming on the carbon cycle and sequestration. For the first time, we applied the in situ soil zymography for identification and localization of hotspots of phosphatase and chitinase activity in the rhizosphere of rice (Oryza sativa L.) under warming effect - (18 and 25 °C) after 14 and 30 days. Thus, we test the hypotheses that due to high inputs of easily degradable organic compounds from the roots canceling effect: strong reduction of temperature sensitvity (Q10~1) of catalytic reactions will not accoure in the rhizosphere. Correspondingly, the Q10 values for reaction rates were always >1, at root-soil interface, with the average range of 1.3 –1.4 Independent of enzymes, canceling was never observed at vicinity of root. Thus, canceling effect is a substrate concentration dependence phenomenon. To our knowledge, this is the first study explored the canceling effect in the rhizosphere. Absence of canceling at root-soil interface for phosphates and chitinase revealed that warming will accelerate P and N mobilization in the rhizosphere. Altogether, for the first time we showed that extent of enzyme activity’s rhizosphere is constant, temporally however, there is a temporal heterogeneity of enzymatic hotspots localization in soil. Thus, increasing in temperature had a positive impact on overall enzyme activities, Rice growth and root development, conducted an enzyme specific impact on hotspots percentage and localization patterns. We conclude that absence of canceling at root-soil interface for tested enzymes revealed that warming will accelerate nutrient mobilization in the rhizosphere more than root free soil
The Rules of Human T Cell Fate in vivo.
The processes governing lymphocyte fate (division, differentiation, and death), are typically assumed to be independent of cell age. This assumption has been challenged by a series of elegant studies which clearly show that, for murine cells in vitro, lymphocyte fate is age-dependent and that younger cells (i.e., cells which have recently divided) are less likely to divide or die. Here we investigate whether the same rules determine human T cell fate in vivo. We combined data from in vivo stable isotope labeling in healthy humans with stochastic, agent-based mathematical modeling. We show firstly that the choice of model paradigm has a large impact on parameter estimates obtained using stable isotope labeling i.e., different models fitted to the same data can yield very different estimates of T cell lifespan. Secondly, we found no evidence in humans in vivo to support the model in which younger T cells are less likely to divide or die. This age-dependent model never provided the best description of isotope labeling; this was true for naïve and memory, CD4+ and CD8+ T cells. Furthermore, this age-dependent model also failed to predict an independent data set in which the link between division and death was explored using Annexin V and deuterated glucose. In contrast, the age-independent model provided the best description of both naïve and memory T cell dynamics and was also able to predict the independent dataset
Study of Soil Compaction Using X-Ray Computed Tomography
The maximum dry density and optimum moisture content obtained from the laboratory compaction curve have been used customarily to characterize the field behavior of compacted soils. It is well known, however, that the microstructure of compacted soils is dependent on the method of compaction. The structure has an important influence on the engineering behavior of compacted soils. Therefore, in order to provide a better description of compacted soils, methods that can quantify the changes in microstructure are needed. In this study, compacted specimens at various densities and water content were scanned using X-ray Computed Tomography (CT). It has been found that there is direct correspondence between the CT numbers, soil dry density and moisture content. The scanning observations showed also the development of shear planes parallel to the surface of the compacted soil, and changes in structure of the soil towards a more uniform arrangement around the point of optimum moisture content. Compaction of the soil beyond the optimum moisture content appears to disperse soil particles with an overall uniform structure
On kilka fishing status in the Caspian Sea
lran's commercial catch on this fish commenced in 1971 and in spite of recent years endeavour to boost the development of kilka fishery, the catch did not exceed 15 thousand tones by year 1991. In this regard a one year survey program conducted in 1991 data collected and stock status identified in Iranian coastline at areas with a seabed depth of 40 to 80 m, in 56 fishing stations spaced at 10 mile intervals along the coast. The survey showed that Clupeonella engruliformis is dominant (91.8 %) followed by Clupeonella grimmi (6.84%) and Clupeonella cultriventris which shared only 1.35% of the total catch. Furthermore 69.95% of Anchovy type kilka, 81.06% of Big eye kilka and 80.88% of common kilka belonged to 2+ and 3+ year class. This major fishing study which carried out in Bandar Anzali using "Catch per Unit Effort" Method, reflects practical variability in fishing and shows that there are more suitable areas with higher densities than Bandar Anzati stations which are yet unexploited. 17 fishing stations from among 56 demonstrate catch rate ranging from 800-1200 kg kilka per unit effort per hour which can h ranked in the first class of kilka yielding grounds, Traditional fishing grounds in Anzali show the catch rate of 400-800 kg per unit effort per hour which is the second class in kilka fishing grounds category. The Iranian coastline bottom topography features sharp slopes which is a favorable habitat for wintering of kilka. The present study shows that possible yearly catch can be promoted up to a ceiling of 100, 1000 metric tons
Automatic Detection of COVID-19 Based on Short-Duration Acoustic Smartphone Speech Analysis
Currently, there is an increasing global need for COVID-19 screening to help reduce the rate of infection and at-risk patient workload at hospitals. Smartphone-based screening for COVID-19 along with other respiratory illnesses offers excellent potential due to its rapid-rollout remote platform, user convenience, symptom tracking, comparatively low cost, and prompt result processing timeframe. In particular, speech-based analysis embedded in smartphone app technology can measure physiological effects relevant to COVID-19 screening that are not yet digitally available at scale in the healthcare field. Using a selection of the Sonde Health COVID-19 2020 dataset, this study examines the speech of COVID-19-negative participants exhibiting mild and moderate COVID-19-like symptoms as well as that of COVID-19-positive participants with mild to moderate symptoms. Our study investigates the classification potential of acoustic features (e.g., glottal, prosodic, spectral) from short-duration speech segments (e.g., held vowel, pataka phrase, nasal phrase) for automatic COVID-19 classification using machine learning. Experimental results indicate that certain feature-task combinations can produce COVID-19 classification accuracy of up to 80% as compared with using the all-acoustic feature baseline (68%). Further, with brute-forced n-best feature selection and speech task fusion, automatic COVID-19 classification accuracy of upwards of 82–86% was achieved, depending on whether the COVID-19-negative participant had mild or moderate COVID-19-like symptom severity
A Distributed Transaction and Accounting Model for Digital Ecosystem Composed Services
This paper addresses two known issues for dynamically
composed services in digital ecosystems. The first
issue is that of efficient distributed transaction management.
The conventional view of transactions is unsuitable as the local
autonomy of the participants is vital for the involvement of
SMEs. The second issue is that of charging for such distributed
transactions, where there will often be dynamically created
services whose composition is not known in advance and might
involve parts of different transactions. The paper provides solutions
for both of these issues, which can be combined to provide
for a unified approach to transaction management and
accounting of dynamically composed services in digital ecosystems
Alternative schemes for measurement-device-independent quantum key distribution
Practical schemes for measurement-device-independent quantum key distribution
using phase and path or time encoding are presented. In addition to immunity to
existing loopholes in detection systems, our setup employs simple encoding and
decoding modules without relying on polarization maintenance or optical
switches. Moreover, by employing a modified sifting technique to handle the
dead-time limitations in single-photon detectors, our scheme can be run with
only two single-photon detectors. With a phase-postselection technique, a
decoy-state variant of our scheme is also proposed, whose key generation rate
scales linearly with the channel transmittance.Comment: 30 pages, 5 figure
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