Strain and band-mixing effects on the excitonic Aharonov-Bohm effect in In(Ga)As/GaAs ringlike quantum dots

Neutral excitons in strained axially symmetric In(Ga)As/GaAs quantum dots with ringlike shape are investigated. Similar to experimental self-assembled quantum rings, the analyzed quantum dots have volcano-like shapes. The continuum mechanical model is employed to determine the strain distribution, and the single-band envelope function approach is adopted to compute the electron states. The hole states are determined by the axially symmetric multiband Luttinger-Kohn Hamiltonian, and the exciton states are obtained from an exact diagonalization. We found that the presence of the inner layer covering the ring opening enhances the excitonic Aharonov-Bohm (AB) oscillations. The reason is that the hole becomes mainly localized in the inner part of the quantum dot due to strain, whereas the electron resides mainly inside the ring-shaped rim. Interestingly, larger AB oscillations are found in the analyzed quantum dot than in a fully opened quantum ring of the same width. Comparison with the unstrained ring-like quantum dot shows that the amplitude of the excitonic Aharonov-Bohm oscillations are almost doubled in the presence of strain. The computed oscillations of the exciton energy levels are comparable in magnitude to the oscillations measured in recent experiments.Comment: 16 pages, 9 figures, accepted for publication in Physical Review

Spectral and Dynamical Properties in Classes of Sparse Networks with Mesoscopic Inhomogeneities

We study structure, eigenvalue spectra and diffusion dynamics in a wide class of networks with subgraphs (modules) at mesoscopic scale. The networks are grown within the model with three parameters controlling the number of modules, their internal structure as scale-free and correlated subgraphs, and the topology of connecting network. Within the exhaustive spectral analysis for both the adjacency matrix and the normalized Laplacian matrix we identify the spectral properties which characterize the mesoscopic structure of sparse cyclic graphs and trees. The minimally connected nodes, clustering, and the average connectivity affect the central part of the spectrum. The number of distinct modules leads to an extra peak at the lower part of the Laplacian spectrum in cyclic graphs. Such a peak does not occur in the case of topologically distinct tree-subgraphs connected on a tree. Whereas the associated eigenvectors remain localized on the subgraphs both in trees and cyclic graphs. We also find a characteristic pattern of periodic localization along the chains on the tree for the eigenvector components associated with the largest eigenvalue equal 2 of the Laplacian. We corroborate the results with simulations of the random walk on several types of networks. Our results for the distribution of return-time of the walk to the origin (autocorrelator) agree well with recent analytical solution for trees, and it appear to be independent on their mesoscopic and global structure. For the cyclic graphs we find new results with twice larger stretching exponent of the tail of the distribution, which is virtually independent on the size of cycles. The modularity and clustering contribute to a power-law decay at short return times

On unitarizability in the case of classical p-adic groups

In the introduction of this paper we discuss a possible approach to the unitarizability problem for classical p-adic groups. In this paper we give some very limited support that such approach is not without chance. In a forthcoming paper we shall give additional evidence in generalized cuspidal rank (up to) three.Comment: This paper is a merged and revised version of ealier preprints arXiv:1701.07658 and arXiv:1701.07662. The paper is going to appear in the Proceedings of the Simons Symposium on Geometric Aspects of the Trace Formul

Scaling of avalanche queues in directed dissipative sandpiles

We simulate queues of activity in a directed sandpile automaton in 1+1 dimensions by adding grains at the top row with driving rate $0 < r \leq 1$. The duration of elementary avalanches is exactly described by the distribution $P_1(t) \sim t^{-3/2}\exp{(-1/L_c)}$, limited either by the system size or by dissipation at defects $L_c= \min (L,\xi)$. Recognizing the probability $P_1$ as a distribution of service time of jobs arriving at a server with frequency $r$, the model represents a new example of the $$ server queue in the queue theory. We study numerically and analytically the tail behavior of the distributions of busy periods and energy dissipated in the queue and the probability of an infinite queue as a function of driving rate.Comment: 11 pages, 9 figures; To appear in Phys. Rev.

Nonuniversal scaling behavior of Barkhausen noise

We simulate Barkhausen avalanches on fractal clusters in a two-dimensional diluted Ising ferromagnet with an effective Gaussian random field. We vary the concentration of defect sites $c$ and find a scaling region for moderate disorder, where the distribution of avalanche sizes has the form $D(s,c,L) = s^{-(1+\tau (c))}{\cal{D}}(sL^{-D_s(c)})$. The exponents $\tau (c)$ for size and $\alpha (c)$ for length distribution, and the fractal dimension of avalanches $D_s(c)$ satisfy the scaling relation $D_s(c)\tau (c) =\alpha (c)$. For fixed disorder the exponents vary with driving rate in agreement with experiments on amorphous Si-Fe alloys.Comment: 5 pages, Latex, 4 PostScript figures include

Analysis of kinetics of poorly water-soluble drug release from hydrogels based on poly (methacrylic acid) and casein with different crosslinker amount

Nowadays, humanity are faced with many challenges which affect health of people all around the globe (such as climate change, new diseases and/or already present ones for which cure has not been found yet – cancer). The efforts of researchers on the field of drug delivery systems bring everyday novel tools for safer and more effective therapy. pH sensitive hydrogels based on poly(methacrylic acid) are recognized as materials with huge potential for controlled release of drugs. The encapsulation and controlled release of many chemotherapeutics is quite challenge due to their poorly water-solubility. In our previous research we overcome this problem by modifying hydrophilic pol(methacrylic acid) with amphiphilic casein and showed that prepared material have potential for encapsulation and controlled release of poorly watersoluble model drug – caffeine (PMAC carriers). In present study we deepened further our research and employed various models: Ritger-Peppas, Higuchi and Kopcha model to analyze how the change of crosslinker amount affect the mechanism of release kinetics of caffeine in medium with pH of 6.8 (which simulated the environment in human intestines). Obtained results showed that only by changing one parameter such as crosslinker amount it is possible to fine tune the type of drug release mechanism, due to which the PMAC carriers would be able to respond to the specific demands of therapy

Magnetization reversal in spin patterns with complex geometry

We study field-driven dynamics of spins with antiferromagnetic interaction along the links of a complex substrate geometry, which is modeled by graphs of a controlled connectivity distribution. The magnetization reversal occurs in avalanches of spin flips, which are pinned by the topological constraints of the underlying graph. The hysteresis loop and avalanche sizes are analyzed and classified in terms of graph's connectivity and clustering. The results are relevant for magnets with a hierarchical spatial inhomogeneity and for design of nanoscale magnetic devices.Comment: 4 pages, 3 color figures, revtex

Influence of 24-hour blood pressure pattern on the rightventricular structure and function in patients with newly diagnosed arterial hypertension

Cilj: Svrha ovog istraživanja je da se odredi uticaj non-dipping profila krvnog pritiska na strukturu, dijastolnu i globalnu funkciju desne komore (DK) kod novootkrivenih pacijenata sa arterijskom hipertenzijom. Metodologija: Ova studija preseka je uključila 167 hipertenzivnih pacijenata sa novootkrivenom hipertenzijom. Svim ispitanicima je urađeno 24-časovno praćenje krvnog pritiska i kompletan ehokardiografski pregled (dvodimenzioni pregled, pulsni i tkivni Doppler). DK hipertrofija je definisana debljinom zida DK ≥ 6.0 mm kod muškaraca i ≥ 5.5 mm kod žena. Rezultati: Dipping profil krvnog pritiska je nađen kod 101 (60%) pacijenta, dok je non-dipping profil bio prisutan kod 66 (40%) hipertenzivnih pacijenata. Dijastolna i globalna funkcija leve komore (LK) su značajno više bile poremećene kod non-dippera u poređenju sa dipperima. Većina parametara dijastolne funkcije LK (E/A, e´/a´, E/e´) se značajno i postepeno pogoršavala idući od ekstremnih dippera ka inverznim dipperima. Nasuprot tome, strukturni parametri LK (IVS, RWT, LK masa indeks) su se značajno razlikovali samo kada su dipperi i ekstremni dipperi poređeni sa ostalim pacijentima. Debljina zida DK kao i (E/e´)t odnos i Tei indeks DK su statistički bili značajno povišeni kod non-dippera u odnosu na dippere. Svi navedeni parametri (debljina zidova DK, (E/e´)t i Tei indeks) progresivno su se rasli od ekstremnih dippera prema inverznim dipperima. Analize rezultata su pokazale da su noćni sistolni i dijastolni pritisak, kao i (E/e´)t odnos nezavisno povezani sa debljinom zida desne komore (p < 0.01 za sve). Non-dipping profil, debljina zida DK, relativna debljina zida LK, (E/e´)m i sistolni oritisak u desnoj komori su nezavisno prediktori dijastolne funkcije DK (E/e´)t, dok su dnevne vrednosti sistolnog i dijastolnog pritiska, kao i noćni dijastolni pritisak i inverzni dipping profil predstavljali prediktore globalne funkcije DK (Tei index DK). Zaključak: Struktura, dijastolna i globalna funkcija DK su značajno poremećene kod non-dippera. Non-dipping i inverzni dipping profil krvnog pritiska predstavljaju nezavisne prediktore dijastolne i globalne funkcije DK.Objective: The purpose of this study was to determine the influence of a non-dipping arterial blood pressure pattern on the right ventricular (RV) structure, diastolic, and global function in recently diagnosed hypertensive patients. Methods: This cross-sectional study included 167 recently diagnosed hypertensive patients. All participants underwent 24 h ambulatory blood pressure monitoring and a complete two-dimensional, pulsed and tissue Doppler echocardiography. RV hypertrophy was defined by RV wall thickness at least 6.0mm in men and at least 5.5 mm in women. Results: The dipping blood pressure pattern was found in 101 (60%) participants, whereas the non-dipping pattern was present in 66 (40%) hypertensive patients. Left ventricular (LV) diastolic and global function were more impaired in non-dippers comparing with dippers. Most of the parameters of the left ventricular diastolic function (E/A, e´/a´, E/e´) significantly and progressively deteriorated from the extreme dippers to the reverse dippers. In contrast, LV structural parameters (IVS, RWT, LV mass index) showed a statistically important difference only by comparing the dippers and the extreme dippers with the rest of the patients. The RV wall thickness as well as the (E/e´)t ratio and the RV Tei index were significantly increased in the non-dippers comparing with dippers. All these parameters (RV wall thickness, (E/e´)t and Tei index) progressively increased from extreme dippers to inverse dippers. Analyses revealed that night-time systolic and diastolic blood pressure, and (E/e´)t ration were independently associated with RV wall thickness (p < 0.001 for all). Non-dipping profile, RV wall thickness, relative wall thickness, (E/e´)m and systolic pressure in right ventricle were identified as independent predictors of RV diastolic function (E/e´)t, whereas daytime systolic and diastolic blood pressure, night-time diastolic blood pressure and inverse dipping profile were independent predictors of RV global function (RV Tei index). Conclusion: RV structure, diastolic, and global functions were significantly impaired in non-dippers. A non-dipping and inverse dipping blood pressure patterns represent the independent predictors of RV diastolic and global function

Reconstruction of Vehicle Trajectory in Crash by Integrating Satellite and Inertial Navigation.

Преко милион особа годишње изгуби живот у саобраћајним несрећама. Према подацима Светске Здравствене Организације, од 1896. године је на овај начин погинуло преко 30 милиона људи1. Веродостојно расветљавање околности саобраћајних несрећа, првенствено судара, може указати и на потенцијалне пропусте у безбедности. Постојећи алати и методе за анализу судара друмских возила, често не пружају довољно информација за једнозначно расветљавање свих околности и узрока догађаја, већ пружају смернице које стручњаци надаље комбинују са другим доступним изворима. Реконструкција сложених и тешких саобраћајних судара често доводи до спорова у судском вештачењу. Уређаји за бележење догађаја при судару се непрестано унапређују, а њихова уградња у возила је de facto обавезна. У току су бројне националне, међународне и струковне иницијативе за њихову даљу стандардизацију и повећање количине корисних информација о судару...Over one million people die in road crashes each year. According to the World Health Organization, since 1986. more than 30 million people died this way. Faithful elucidation of traffic crash circumstances can lead to revealing of safety issues. Existing crash investigation tools and methods provide only directions of approach to investigators, and therefore can lead to ambiguous conclusions in otherwise solvable cases. Complex and fatal road vehicle crashes are often a matter of dispute in forensic investigation. Crash Event Data Recorders (EDRs), which are today standard equipment of passenger cars, provide sensor captures for post-accident forensic analysis. There are many ongoing national, international and expert initiatives for further standardization and improvement of EDRs..