4,023 research outputs found
Hopping magneto-transport via nonzero orbital momentum states and organic magnetoresistance
In hopping magnetoresistance of doped insulators, an applied magnetic field
shrinks the electron (hole) s-wave function of a donor or an acceptor and this
reduces the overlap between hopping sites resulting in the positive
magnetoresistance quadratic in a weak magnetic field, B. We extend the theory
of hopping magnetoresistance to states with nonzero orbital momenta. Different
from s-states, a weak magnetic field expands the electron (hole) wave functions
with positive magnetic quantum numbers, m > 0, and shrinks the states with
negative m in a wide region outside the point defect. This together with a
magnetic-field dependence of injection/ionization rates results in a negative
weak-field magnetoresistance, which is linear in B when the orbital degeneracy
is lifted. The theory provides a possible explanation of a large low-field
magnetoresistance in disordered pi-conjugated organic materials (OMAR).Comment: 4 pages, 3 figure
Dynamical Semigroups for Unbounded Repeated Perturbation of Open System
We consider dynamical semigroups with unbounded Kossakowski-Lindblad-Davies
generators which are related to evolution of an open system with a tuned
repeated harmonic perturbation. Our main result is the proof of existence of
uniquely determined minimal trace-preserving strongly continuous dynamical
semigroups on the space of density matrices. The corresponding dual W
*-dynamical system is shown to be unital quasi-free and completely positive
automorphisms of the CCR-algebra. We also comment on the action of dynamical
semigroups on quasi-free states
Cystomanometry – One of the Assessment Methods of the Urodynamic Indexes in Patients with Infiltrative Cervical Cancer
Aim: To evaluate contractile function of urinary bladder in patients with infiltrative cervical cancer after nerve-sparing radical hysterectomy (NSRH).Patients and Methods: Ninety patients with infiltrative cervical cancer were treated with nerve-sparing radical hysterectomy (n=45, NSRH group), or radical hysterectomy (RHE III) without preservation of pelvic autonomic plexuses (n=45, RHE group). Cystomanometry was carried out using urodynamic apparatus “Uro-Pro” by standard method.Results: Using cystomanometry, we have evaluated the main urodynamic indexes such as pressure upon bladder filling (P1), first vesical tenesmus pressure (P2); change of detrusor pressure upon change of bladder volume (P), volume of urinary bladder (V), and complience of urinary bladder wall (C) at preoperative period and postoperative period in both groups of patients. While at preoperative period P1 indexes did not differ significantly between the groups, after NSRH performance, P1 values were significantly higher than P1 values in the group of patients treated with RHE III (8,29±1,1 cm H2O versus 3,51±0,8 cm H2O (р<0,05)). P2 indexes in patients from both groups before and after surgical treatment differed significantly and were 6,82±0,4 cm H2O and 12,27±1,2 cm H2O (р<0,05) in NSRH group, and 5,44±0,6 cm H2O and 10,62±1,1 cm H2O (р<0,05) in RHE III group. The P value in both patients groups before and after the surgical treatments was significantly different, and demonstrated a gradual elevation of urinary bladder pressure, especially in the patients from RHE III treated group. Urinary bladder volume at preoperative and postoperative periods in NSRH-treated group remained practically unaltered (209,78±14,2 ml and 216,86±14,9 ml (р>0,5) respectively), while in the patients from RHE III-treated group after surgical treatment an urinary bladder volume significantly decreased from 188,4±10,5 ml to 161,9±9,8 ml (р<0,05). An analysis of compliance of urinary bladder wall (C) has shown that after surgical treatment in RHE group C value decreased by 75% while in NSE group this index decreased just by 25%.Conclusions: The data of urodynamic study evidence the better preservation of urinary bladder functions in patients with infiltrative cervical cancer after NSRH than in the patients treated with RHE III
On Classification of QCD defects via holography
We discuss classification of defects of various codimensions within a
holographic model of pure Yang-Mills theories or gauge theories with
fundamental matter. We focus on their role below and above the phase transition
point as well as their weights in the partition function. The general result is
that objects which are stable and heavy in one phase are becoming very light
(tensionless) in the other phase. We argue that the dependence of the
partition function drastically changes at the phase transition point, and
therefore it correlates with stability properties of configurations. Some
possible applications for study the QCD vacuum properties above and below phase
transition are also discussed.Comment: 21 pages, 2 figure
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