230 research outputs found
Steady state fluctuations of the dissipated heat for a quantum stochastic model
We introduce a quantum stochastic dynamics for heat conduction. A multi-level
subsystem is coupled to reservoirs at different temperatures. Energy quanta are
detected in the reservoirs allowing the study of steady state fluctuations of
the entropy dissipation. Our main result states a symmetry in its large
deviation rate function.Comment: 41 pages, minor changes, published versio
A new numerical approach to Anderson (de)localization
We develop a new approach for the Anderson localization problem. The
implementation of this method yields strong numerical evidence leading to a
(surprising to many) conjecture: The two dimensional discrete random
Schroedinger operator with small disorder allows states that are dynamically
delocalized with positive probability. This approach is based on a recent
result by Abakumov-Liaw-Poltoratski which is rooted in the study of spectral
behavior under rank-one perturbations, and states that every non-zero vector is
almost surely cyclic for the singular part of the operator.
The numerical work presented is rather simplistic compared to other numerical
approaches in the field. Further, this method eliminates effects due to
boundary conditions.
While we carried out the numerical experiment almost exclusively in the case
of the two dimensional discrete random Schroedinger operator, we include the
setup for the general class of Anderson models called Anderson-type
Hamiltonians.
We track the location of the energy when a wave packet initially located at
the origin is evolved according to the discrete random Schroedinger operator.
This method does not provide new insight on the energy regimes for which
diffusion occurs.Comment: 15 pages, 8 figure
GENETIC ANALYSIS OF PURE ARABIAN BREEDING IN THE REPUBLIC OF CROATIA
Pure arab breeding in the Republic of Croatia has very long tradition. Till the 18th century organized breeding was implemented only in bishop Stud Farm Đakovo. Afterwards pure arab breeding was implemented in many private Stud Farms mostly located in Slavonian and Srijem region. Pure arab, traditional arab and araber (arabrasse) population of horses make together arabian breeding in the Republic of Croatia. Numerical strength of these three populations has increasing trend through out the years. First imports which were ground for foundation of pure arab breeding in Croatia realized in year 1991. Today, population of pure arab breeding count 37 head, from which 28 is imported and 9 born in Croatia. Pedigree depth in 4, 5, 6, 7, 8, 9 and 10 generation show average coefficient of inbreeding of 1.899%, 3.15%, 4.413%, 5.434%, 6.243%, 6.974% and 7.552%. According to genealogy in all pedigree depths, coefficient of inbreeding was higher (P < 0.01) in imported arab horses than in those born in Croatia
Subwavelength hole arrays with nanoapertures fabricated by scanning probe nanolithography
Owing to their surface plasmon-based operation, arrays of subwavelength holes show extraordinary electromagnetic transmission and intense field localizations of several orders of magnitude. Thus they were proposed as the basic building blocks for a number of applications utilizing the enhancement of nonlinear optical effects. We designed and simulated nanometer-sized subwavelength holes using an analytical approach. In our experiments we used the scanning probe method for nanolithographic fabrication of subwavelength hole arrays in silver layers sputtered on a positive photoresist substrate. We fabricated ordered nanohole patterns with different shapes, dispositions and proportions. The smallest width was about 60 nm. We characterized the fabricated samples by atomic force microscopy
GENETIC ANALYSIS OF PURE ARABIAN BREEDING IN THE REPUBLIC OF CROATIA
Pure arab breeding in the Republic of Croatia has very long tradition. Till the 18th century organized breeding was implemented only in bishop Stud Farm Đakovo. Afterwards pure arab breeding was implemented in many private Stud Farms mostly located in Slavonian and Srijem region. Pure arab, traditional arab and araber (arabrasse) population of horses make together arabian breeding in the Republic of Croatia. Numerical strength of these three populations has increasing trend through out the years. First imports which were ground for foundation of pure arab breeding in Croatia realized in year 1991. Today, population of pure arab breeding count 37 head, from which 28 is imported and 9 born in Croatia. Pedigree depth in 4, 5, 6, 7, 8, 9 and 10 generation show average coefficient of inbreeding of 1.899%, 3.15%, 4.413%, 5.434%, 6.243%, 6.974% and 7.552%. According to genealogy in all pedigree depths, coefficient of inbreeding was higher (P < 0.01) in imported arab horses than in those born in Croatia
Measurement of renal function by calculation of fractional uptake of technetium-99m dimercaptosuccinic acid
BACKGROUND: The purpose of this study was to set up normal values of the
fractional uptake (FU) of technetium-99m dimercaptosuccinic acid in adults and
in the pediatric population, as well as to evaluate the validity of this parameter
at different levels of renal function.
MATERIAL AND METHODS: A total of 86 subjects was divided into seven groups.
In group A there were 23 potential kidney donors and in group B, 18 children in
remission after a first urinary tract infection. Another three groups consisted
of patients with diabetes i.e. group C, seven patients with normal values of albuminuria,
group D, 16 patients with microalbuminuria and group E, five patients with macroalbuminuria.
In group F, there were ten patients with a well-functioning transplanted kidney
and in group G, seven patients with suspected acute rejection. The procedure began
with the quantification of the doses of 99mTc-DMSA to be injected and the measurement
of the empty syringe lying on the gamma camera collimator. Thereafter, four planar
views of the kidneys were acquired three hours after the injection. The counts
from the posterior and anterior views were subtracted for background and corrected
for radioactive decay time and patient thickness. The FU was calculated by the
geometric mean of counts per second from the posterior and anterior view. It was
expressed as a fraction of the injected dose.
RESULTS: The mean values of FU in healthy adults were 0.227 ± 0.077 for
one kidney and 0.454 ± 0.146 for both kidneys. The mean values of FU for the left
and right kidney were 0.225 ± ± 0.071 and 0.229 ± 0.079, respectively. In children,
the mean values were 0.220 ± 0.092 for one kidney and 0.432 ± 0.094 for both kidneys.
The highest values of FU of 0.322 ± 0.078 (0.644 ± 0.138 for both kidneys) were
measured in group C. In group D, FU was 0.185 ± 0.065 (0.361 ± 0.125 for both
kidneys) and in group E 0.082 ± 0.040 (0.163 ± 0.080 total). In patients with
a transplanted kidney, fractional uptake was 0.162 ± ± 0.039 in group F and 0.065
± 0.021 in group G. There was no significant difference in the values of FU between
healthy adults and children. The uptake in group C was 41% higher than in group
A and the difference was statistically significant. In groups D and E, the uptake
was significantly lower than in A. In both groups of patients with transplanted
kidneys, the uptake was significantly lower than in control group. The correlation
between FU and biochemical parameters of renal function [blood urea nitrogen (BUN),
serum creatinine (Cr) and creatinine clearance (CCr)] was significant: FU/BUN
r = –0.86; FU/Cr r = –0.77; FU/CCr r = 0.60.
CONCLUSION: Fractional uptake of99mTc-DMSA could serve as a sensitive
parameter of renal function. The mean values of FU in adults were 0.454 and in
children 0.432. There was no significant difference between values for the left
and right kidney. In diabetes mellitus, fractional uptake correlated well with
the degree of diabetic nephropathy. In patients with a well-functioning transplant,
the uptake was slightly reduced. Low values of fractional uptake in acute rejection
were related to lesions in kidney blood vessels and in tubular cells
A note on the Landauer principle in quantum statistical mechanics
The Landauer principle asserts that the energy cost of erasure of one bit of
information by the action of a thermal reservoir in equilibrium at temperature
T is never less than . We discuss Landauer's principle for quantum
statistical models describing a finite level quantum system S coupled to an
infinitely extended thermal reservoir R. Using Araki's perturbation theory of
KMS states and the Avron-Elgart adiabatic theorem we prove, under a natural
ergodicity assumption on the joint system S+R, that Landauer's bound saturates
for adiabatically switched interactions. The recent work of Reeb and Wolf on
the subject is discussed and compared
'Return to equilibrium' for weakly coupled quantum systems: a simple polymer expansion
Recently, several authors studied small quantum systems weakly coupled to
free boson or fermion fields at positive temperature. All the approaches we are
aware of employ complex deformations of Liouvillians or Mourre theory (the
infinitesimal version of the former). We present an approach based on polymer
expansions of statistical mechanics. Despite the fact that our approach is
elementary, our results are slightly sharper than those contained in the
literature up to now. We show that, whenever the small quantum system is known
to admit a Markov approximation (Pauli master equation \emph{aka} Lindblad
equation) in the weak coupling limit, and the Markov approximation is
exponentially mixing, then the weakly coupled system approaches a unique
invariant state that is perturbatively close to its Markov approximation.Comment: 23 pages, v2-->v3: Revised version: The explanatory section 1.7 has
changed and Section 3.2 has been made more explici
Einfluss gewisser Faktoren auf die Bestimmung des biochemischen Sauerstoffbedarfs (BSB) der Zellstoffabwasser
U prethodnim radovima praćena je promjena BPK u inkubacionom periodu od O do 5 dana u otpadnim vodama proizvodnje celuloze. Uočene poteškoće kod određivanja se sistematizuju i prati se njihov uticaj na rezultat testa. Ispitivanjima su utvrđeni optimalni uslovi za dobijanje reproduktivnih rezultata.In den vorläufigen Arbeiten hat man die Änderung von BSB während der Inkubationsperiode von 0-5 Tagen bei den Zellstoffabwässern gefolgt. Die bei der Bestimmung bemerkten Schwierigkeiten wurden systematisiert und deren Einfluss auf die Testergebnisse wurde gefolgt. Durch Untersuchungen wurden die optimalen Bedingungen bestimmt die zur Erreichung von reproduzierbaren Ergebnissen führen
The application of hydrogen-palladium electrode for potentiometric acid-base determinations in tetrahydrofuran
The application of the hydrogen-palladium electrode (H2/Pd) as the indicator electrode for the determination of relative acidity scale (Es, mV) of tetrahydrofuran (THF) and the potentiometric titrations of acids in this solvent was investigated. The relative acidity scale tetrahydrofuran was determined from the difference half-neutralization potentials of perchloric acid and tetrabutylammonium hydroxide (TBAH), which were measured by using both H2/Pd-SCE and glass-SCE electrode pairs. The experimentally obtained value of Es scale THF with a H2/Pd-SCE electrode pair was 1155 mV, and those obtained with glass-SCE electrode pair 880 mV. By using a H2/Pd indicator electrode, the individual acids (benzoic acid, palmitic acid, maleic acid, acetyl acetone, α-naphthol) and two component acid mixtures (benzoic acid + α-naphthol, palmitic acid + α-naphthol, maleic acid + α-naphthol and maleic acid + ftalic acid) were titrated with a standard solution of TBAH. In addition, sodium methylate and potassium hydroxide proved to be very suitable titrating agents for titrating of the individual acids and the acids in mixtures, respectively. The relative error of the determination of acids in mixture was less than 3%. The results are in agreement with those obtained by a conventional glass electrode. The advantages of H2/Pd electrode over a glass electrode in potentiometric acid-base determinations in tetrahydrofuran lie in the following: this electrode gives wider relative acidity scale THF, higher the potential jumps at the titration end-point and relatively fast response time; furthermore, it is very durable, simple to prepare and can be used in the titrations of small volumes. [Projekat Ministarstva nauke Republike Srbije, br.172051
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