2,487 research outputs found
On a class of rational and mixed soliton-rational solutions of Toda lattice
A class of rational solutions of Toda lattice satisfying certain Backlund
transformations and a class of mixed rational-soliton solutions (quasisolitons)
in wronskian formare obtained using the method of Ablowitz and Satsuma. Also an
extended class of rational solutions are found using an appropriate recursion
relation. They are also solutions of Boussinesq equation and it is conjectured
that there is a larger class of common solutions of both equations.Comment: 10 pages, Late
Differences of interface and bulk transport properties in polymer field-effect devices
The influence of substrate treatment with self-assembled monolayers and
thermal annealing was analysed by electrical and structural measurements on
field-effect transistors (FETs) and metal-insulator-semiconductor (MIS) diodes
using poly(3-hexylthiophene) (P3HT) as a semiconducting polymer and Si/SiO2
wafers as a substrate. It is found that surface treatment using silanising
agents like hexamethyldisilazane (HMDS) and octadecyltrichlorosi-lane (OTS) can
increase the field-effect mobility by up to a factor of 50, reaching values in
saturation of more than 4E-2 cm^2/Vs at room temperature. While there is a
clear correlation between the obtained field-effect mobility and the contact
angle of water on the treated substrates, X-ray diffraction and capacitance
measurements on MIS diodes show that structural and electrical properties in
the bulk of the P3HT films are not influenced by the surface treatment. On the
other hand, thermal annealing is found to cause an increase of grain size, bulk
relaxation frequency and thereby of the mobility perpendicular to the SiO2/P3HT
interface, but has very little influence on the field-effect mobility.
Temperature dependent investigations on MIS diodes and FETs show that the
transport perpendicular to the substrate plane is thermally activated and can
be described by hopping in a Gaussian density of states, whereas the
field-effect mobility in the substrate plane is almost temperature independent
over a wide range. This investigations reveal significant differ-ences between
interface and bulk transport properties in polymer field-effect devices.Comment: accepted at Organic electronic
Appendicopathies in emergency surgery - a substantian problem
Catedra Chirurgie, FEC MF, USMF „N. Testemițanu”, Chișinău, Moldova, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Dacă pînă în prezent au fost atinse succese notabile în chirurgia apendicitei acute, nu ne dă posibilitatea să constatăm faptul că problema este rezolvată
definitiv, au rămas probleme neclare şi discutabile: 1) nu este perfectă diagnostica; 2) sunt divergenţe în privinţa tacticii chirurgicale; 3) lipsesc intraoperator criteriile unice a modificărilor macroscopice; 4) sunt divergenţe în diagnosticul clinic şi rezultatele morfohistologice. Studiile din literatura franceză au constatat faptul că la 20% din cei operaţi s-a înlăturat apendicele neafectat. Au fost studiaţi 235 pacienţi cu vîrsta 14-80 ani. Femei-bărbaţi 1,5:1. Durerea manifestată la 100% bolnavi caracterizată prin (spontană, permanentă, intermitentă, difuză, localizată, violentă, transfixiantă, iradiere
topografică). Defens muscular, meteorism, pulsmetria, temperatura corpului s-au manifestat în raport variabil. Simptoamele subiective (diaree, constipaţie, vomă, s.Koher, greţuri) prezente la toţi bolnavii. Prevalenţa s. obiective (Blumberg, Rowzing, triada Dieulafoy, Bartomie-Mihelson, Coop) a fost notată la bolnavii cu semne evidente de apendicită acută. La 80% - hiperleucocitoză. Polinucleoza a fost marcată variabil: normal, moderată, notabilă, excesivă şi majorată enorm. USG abdominală : pneumatoză intestinală, apendice vizualizat, mobil, imobil, îngroşat, lichid în cavitatea abdominală notate variabil. Intraoperator s-a înregistrat lichid seros, serohemoragic, seropurulent, purulent cu variaţii. S-a constatat faptul că 22% nu au modificări patomorfologice în apendice. Coeficientul identificării diagnosticului clinic cu cel patomorfologic este în raport 4,5:1. Acestea sunt cazurile apendicopatiilor cu manifestări clinice evidente şi cu lipsă de substrat patomorfologic, mai bine spus, apendice neafectat. Concluzii:
1. Apendicopatiile diferă radical de apendicita acută prin faptul că ele se manifestă clinic printr-un complex simptomatologic evident de apendicită acută şi cu lipsa totală a substratului patomorfologic. 2. Pentru a clarifica aceste probleme definitiv, va fi necesar un studiu clinic mai profund si identificarea mai sigură a modificărilor patologomorfologice.
3. Extirparea apendicelui alterat în apendicopatie, cauză a fenomenelor dureroase sau a crizelor repetate, se impune ca singura măsură de a vindeca răul prezent şi de a evita pericolele viitorului.The fact that until now has been achieved notable success in the surgery of acute appendicitis doesn’t give us the possibility to say that the problem is entirely solved; there still are many confusing and contestable problems:
1) the diagnosis is not perfect.
2) there are many divergences about the surgical tactics.
3) there are no unique criteriafor macroscopical changes during the operation.
4) there are different opinionsamong surgeons as for clinical diagnosis and morphological characteristics.
The study of French literature have concluded that in the case of 20% of operations unaffected appendix has been removed. 235 patients aged 14-80 years in rapport of 1,5:1 women and men have been examined. The pain manifested at 100% of patients was characterized as spontaneous, continuous, intermittent, diffuse, localized, violent, topographical radiation. The muscle defense, flatulence, pulsation, high temperature occurred in several cases. Subjective symptoms (diarrhea, constipation, vomiting, Koher’s
sign and nausea) have been noticed at all the patients. The prevalence of objective symptoms (Blumberg, Rowzing, Dieulafoy triad, Bartomie-Mihelson, Coop) has been noticed at the patients with obvious signs of acute appendicitis. 80% manifested hyperleukocytosis. The mark of polynucleosys was variable: normal, moderate, noticeable, excessive and increased enormously. The ultrasound check of abdomen showed intestinal pneumatosis, visible, mobile, immobile, thickened, fluid appendix in the abdominal cavity has been detected in several cases. Intraoperative serous, sero-hemorrhagic,
seropurulent and purulentliquid was noticed 22% of patients had no pathomorphologicchanges coefficient was 4,5:1. These are the appendicopathy
cases with clinicalmanifestations and lack of pathomorphological base, batter said: normal, unaffected appendix.
Conclusions:
1. Appendicopathies differ radically from acute appendicitis in that they manifest clinically evident symptomatic complex of acute appendicitis and
total lack of pathomorphological substrate.
2. To clarify these issues ultimately a deeper clinical study and a more reliable identification of pathomorphological changes would be necessary.
3. The removal of altered appendix in appendicitis, cause of pain phenomena or repeated crisis imposes itself as the only measure to cure the present
disease and to avoid future dangers
Localised and nonlocalised structures in nonlinear lattices with fermions
We discuss the quasiclassical approximation for the equations of motions of a
nonlinear chain of phonons and electrons having phonon mediated hopping.
Describing the phonons and electrons as even and odd grassmannian functions and
using the continuum limit we show that the equations of motions lead to a
Zakharov-like system for bosonic and fermionic fields. Localised and
nonlocalised solutions are discussed using the Hirota bilinear formalism.
Nonlocalised solutions turn out to appear naturally for any choice of wave
parameters. The bosonic localised solution has a fermionic dressing while the
fermionic one is an oscillatory localised field. They appear only if some
constraints on the dispersion are imposed. In this case the density of fermions
is a strongly localised travelling wave. Also it is shown that in the multiple
scales approach the emergent equation is linear. Only for the resonant case we
get a nonlinear fermionic Yajima-Oikawa system. Physical implications are
discussed.Comment: 7 pages, LaTeX, no figures. to appear in Europhysics Latter
Vertical Heating Structures Associated with the MJO as Characterized by TRMM Estimates, ECMWF Reanalyses, and Forecasts: A Case Study during 1998/99 Winter
The Madden–Julian oscillation (MJO) is a fundamental mode of the tropical atmosphere variability that exerts significant influence on global climate and weather systems. Current global circulation models, unfortunately, are incapable of robustly representing this form of variability. Meanwhile, a well-accepted and comprehensive theory for the MJO is still elusive. To help address this challenge, recent emphasis has been placed on characterizing the vertical structures of the MJO. In this study, the authors analyze vertical heating structures by utilizing recently updated heating estimates based on the Tropical Rainfall Measuring Mission (TRMM) from two different latent heating estimates and one radiative heating estimate. Heating structures from two different versions of the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses/forecasts are also examined. Because of the limited period of available datasets at the time of this study, the authors focus on the winter season from October 1998 to March 1999.
The results suggest that diabatic heating associated with the MJO convection in the ECMWF outputs exhibits much stronger amplitude and deeper structures than that in the TRMM estimates over the equatorial eastern Indian Ocean and western Pacific. Further analysis illustrates that this difference might be due to stronger convective and weaker stratiform components in the ECMWF estimates relative to the TRMM estimates, with the latter suggesting a comparable contribution by the stratiform and convective counterparts in contributing to the total rain rate. Based on the TRMM estimates, it is also illustrated that the stratiform fraction of total rain rate varies with the evolution of the MJO. Stratiform rain ratio over the Indian Ocean is found to be 5% above (below) average for the disturbed (suppressed) phase of the MJO. The results are discussed with respect to whether these heating estimates provide enough convergent information to have implications on theories of the MJO and whether they can help validate global weather and climate models
Combining Satellite Microwave Radiometer and Radar Observations to Estimate Atmospheric Latent Heating Profiles
In this study, satellite passive microwave sensor observations from the TRMM Microwave Imager (TMI) are utilized to make estimates of latent + eddy sensible heating rates (Q1-QR) in regions of precipitation. The TMI heating algorithm (TRAIN) is calibrated, or "trained" using relatively accurate estimates of heating based upon spaceborne Precipitation Radar (PR) observations collocated with the TMI observations over a one-month period. The heating estimation technique is based upon a previously described Bayesian methodology, but with improvements in supporting cloud-resolving model simulations, an adjustment of precipitation echo tops to compensate for model biases, and a separate scaling of convective and stratiform heating components that leads to an approximate balance between estimated vertically-integrated condensation and surface precipitation. Estimates of Q1-QR from TMI compare favorably with the PR training estimates and show only modest sensitivity to the cloud-resolving model simulations of heating used to construct the training data. Moreover, the net condensation in the corresponding annual mean satellite latent heating profile is within a few percent of the annual mean surface precipitation rate over the tropical and subtropical oceans where the algorithm is applied. Comparisons of Q1 produced by combining TMI Q1-QR with independently derived estimates of QR show reasonable agreement with rawinsonde-based analyses of Q1 from two field campaigns, although the satellite estimates exhibit heating profile structure with sharper and more intense heating peaks than the rawinsonde estimates.
A new approach to radon temporal correction factor based on active environmental monitoring devices
The present study aims to identify novel means of increasing the accuracy of the estimated annual indoor radon concentration based on the application of temporal correction factors to short-term radon measurements. The necessity of accurate and more reliable temporal correction factors is in high demand, in the present age of speed. In this sense, radon measurements were continuously carried out, using a newly developed smart device accompanied by CR-39 detectors, for one full year, in 71 residential buildings located in 5 Romanian cities. The coefficient of variation for the temporal correction factors calculated for combinations between the start month and the duration of the measurement presented a low value (less than 10%) for measurements longer than 7 months, while a variability close to 20% can be reached by measurements of up to 4 months. Results obtained by generalized estimating equations indicate that average temporal correction factors are positively associated with CO2 ratio, as well as the interaction between this parameter and the month in which the measurement took place. The impact of the indoor-outdoor temperature differences was statistically insignificant. The obtained results could represent a reference point in the elaboration of new strategies for calculating the temporal correction factors and, consequently, the reduction of the uncertainties related to the estimation of the annual indoor radon concentration.Acknowledgements: The research is supported by the project ID P_37_229, Contract No. 22/01.09.2016, with the title, Smart Systems for Public Safety through Control and Mitigation of Residential Radon linked with Energy Efficiency Optimization of Buildings in Romanian Major Urban Agglomerations SMART-RAD-EN” of the POC Programme
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