Anisotropic Electron Spin Lifetime in (In,Ga)As/GaAs (110) Quantum Wells

Anisotropic electron spin lifetimes in strained undoped (In,Ga)As/GaAs (110) quantum wells of different width and height are investigated by time-resolved Faraday rotation and time-resolved transmission and are compared to the (001)-orientation. From the suppression of spin precession, the ratio of in-plane to out-of-plane spin lifetimes is calculated. Whereas the ratio increases with In concentration in agreement with theory, a surprisingly high anisotropy of 480 is observed for the broadest quantum well, when expressed in terms of spin relaxation times.Comment: 4 pages, 4 figures, revise

Parsimonious Kernel Fisher Discrimination

By applying recent results in optimization transfer, a new algorithm for kernel Fisher Discriminant Analysis is provided that makes use of a non-smooth penalty on the coefficients to provide a parsimonious solution. The algorithm is simple, easily programmed and is shown to perform as well as or better than a number of leading machine learning algorithms on a substantial benchmark. It is then applied to a set of extreme small-sample-size problems in virtual screening where it is found to be less accurate than a currently leading approach but is still comparable in a number of cases

The ultrasonically guided percutaneous nephrostomy by trocar – the indications and efficacy

Catedra de Oncologie, Universitatea de Stat de Medicină și Farmacie ”Nicolae Testemițanu”, IMSP Institutul Oncologic, Chișinău, Republica Moldova, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaIntroducere: Nefrostomia percutanată ecoghidată (NPC) este o procedură intervențională minim-invazivă utilizată pentru decompresia sistemului pielo-caliceal renal. În 1955, Goodwin, a publicat un raport care descrie această procedură. Uropatia obstructivă este o afecțiune întâlnită frecvent în tumorile organelor bazinului mic şi constituie aprox. 25% în structura maladiilor oncologice. NPC se poate efectua prin 2 metode: - clasică - prin trocar (unimomentană ) TrNPC Material şi metode: Lotul de studiu a constituit 50 pacienți, tratați în perioada 2016-2019 în departamentul de urologie a IMSP IO, cărora le-au fost aplicate 70 de TrNPC. Metoda a fost implimentată cu succes, iar materialul publicat este propria experiență. Rezultate: Instrumentarul utilizat: ecograful și sonda abdominală cu ghidaj, set de nefrostomie, trocar N9 Fr. Din lotul constituit, femei au fost - 37 (74%) și - 14 (28%) bărbați, vârsta medie fiind de 62 ani. Dintre aceștia, 28 (56%) – bolnavi la prima adresare, 22 (44%) – adresare repetată. Indicațiile pentru TrNPC: pacienții cu tumori avansate ale bazinului mic cu diferite grade de hidronefroză. TrNPC s-au instalat: pe stânga la 19 pacienți, pe dreapta 15, iar 18 pacienți bilateral. În dependență de stadiul tumoral: stadiul I - 2(4%), stadiul II – 3(6%), stadiul III-IV - 45 (90%). Pentru pacienții cu stadiile I – II de boală, indicațiile către TrNPC a servit: traumatismul iatrogen intraoperator sau strictura anastamozei uretero-intestinale postoperatorii. Complicații întâlnite: hemoragie difuză – 2(4%), dislocația drenului cu reinstalarea acestuia 3(6%). Concluzii: 1.TrNPC este o metoda unimomentană mult mai efectivă şi sigură în drenarea obstrucțiilor infra renale în compaţie cu NPC clasică. 2. Având complicații minime TrNPC poate fi efectuată în condiții de ambulatoriu.Background: Ultrasound-guided percutaneous nephrostomy (PNE) is a minimally invasive method used to decompress the renal pyelocalcal system. Goodwin in 1955 published a report describing this procedure. Obstructive uropathy is a common disease founded in pelvic organ tumors and constitutes - 25% of all oncological diseases. PNE can be performed by 2 methods: - classic (multiple maneuvers) - by trocar ( unimoment method ) Methods and materials: The study group consists of 50 patients treated during the 2016-2019 period in the urology department of the IMSP IO, 70 TrPNEs being applied. The method was successfully implemented and the material is own experience. Results: The used instruments: ultrasound scan, abdominal guided catheter, nephrostomy set, trocar N9 Fr. Of the patients group, women were - 37 (74%), men were - 14 (28%), the mean age was 62 years. From them 28 (56%) were first addressed patients and 22 (44%) were patients at secondary address. The TrPNEs indications were: advanced pelvic tumors with clinical manifested hidronefrose. Were performed TrPNE: on the left at 19 patients, on the right at 15 patients, bilateral at 18 patients. The tumor grade: I degree – 2 (4%), II degree – 3 (6%), III – IV degree – 45 (90%). For the I – II degree the TrPNEs indication was the iatrogenic trauma or the ureter-intestinal anastomose stricture. The procedural complications: diffuse haemorrhage – 2 (4%), PNE tube complications 3 (6%). Conclusions: 1.TrPNE it is a more effective and safely unimoment method used for the infrarenal obstructions then the classic method. 2. TrPNE has minimal complications, also it is possible to use the procedure in ambulatory conditions

Ray-acoustic caustic formation and timing effects from ocean sound-speed relative curvature

Author Posting. © Acoustical Society of America, 1994. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 96 (1994): 1033-1046, doi:10.1121/1.410380.Using deterministic ray-acoustic modeling of 1000-km propagation in the North Pacific, a depth-dependent parameter of ocean sound channels has been found to strongly influence geometrical ray propagation. This parameter is the sound speed times the second vertical derivative of sound speed divided by the square of the first derivative. Ray and wavefront timing and intensity can be influenced within realistic ocean sound channels by unpredictable wavefront triplications and caustics. These triplications are associated with large values of the parameter at ray turning points. The parameter, a relative curvature, behaves as a random variable because of ocean finestructure, causing the unpredictability. The relative curvature has a higher mean value near the sound-speed minimum for both an internal-wave model and actual data, so that this mechanism is a plausible explanation of poor multipath resolution and identifiability late in North Pacific pulse trains.This work was supported by the Office of Naval Technology (N00014-90-C-0098) and the Office of Naval Research, Ocean Acoustics Program (N00014-92-J-1162)

Fractal Descriptors in the Fourier Domain Applied to Color Texture Analysis

The present work proposes the development of a novel method to provide descriptors for colored texture images. The method consists in two steps. In the first, we apply a linear transform in the color space of the image aiming at highlighting spatial structuring relations among the color of pixels. In a second moment, we apply a multiscale approach to the calculus of fractal dimension based on Fourier transform. From this multiscale operation, we extract the descriptors used to discriminate the texture represented in digital images. The accuracy of the method is verified in the classification of two color texture datasets, by comparing the performance of the proposed technique to other classical and state-of-the-art methods for color texture analysis. The results showed an advantage of almost 3% of the proposed technique over the second best approach.Comment: Chaos, Volume 21, Issue 4, 201

Dynamic quantum clustering: a method for visual exploration of structures in data

A given set of data-points in some feature space may be associated with a Schrodinger equation whose potential is determined by the data. This is known to lead to good clustering solutions. Here we extend this approach into a full-fledged dynamical scheme using a time-dependent Schrodinger equation. Moreover, we approximate this Hamiltonian formalism by a truncated calculation within a set of Gaussian wave functions (coherent states) centered around the original points. This allows for analytic evaluation of the time evolution of all such states, opening up the possibility of exploration of relationships among data-points through observation of varying dynamical-distances among points and convergence of points into clusters. This formalism may be further supplemented by preprocessing, such as dimensional reduction through singular value decomposition or feature filtering.Comment: 15 pages, 9 figure