Magnetotransport in Double Quantum Well with Inverted Energy Spectrum: HgTe/CdHgTe

We present the first experimental study of the double-quantum-well (DQW) system made of 2D layers with inverted energy band spectrum: HgTe. The magnetotransport reveals a considerably larger overlap of the conduction and valence subbands than in known HgTe single quantum wells (QW), which may be regulated by an applied gate voltage $V_g$. This large overlap manifests itself in a much higher critical field $B_c$ separating the range above it where the quantum peculiarities shift linearly with $V_g$ and the range below with a complicated behavior. In the latter case the $N$-shaped and double-$N$-shaped structures in the Hall magnetoresistance $\rho_{xy}(B)$ are observed with their scale in field pronouncedly enlarged as compared to the pictures observed in an analogous single QW. The coexisting electrons and holes were found in the whole investigated range of positive and negative $V_g$ as revealed from fits to the low-field $N$-shaped $\rho_{xy}(B)$ and from the Fourier analysis of oscillations in $\rho_{xx}(B)$. A peculiar feature here is that the found electron density $n$ remains almost constant in the whole range of investigated $V_g$ while the hole density $p$ drops down from the value a factor of 6 larger than $n$ at extreme negative $V_g$ to almost zero at extreme positive $V_g$ passing through the charge neutrality point. We show that this difference between $n$ and $p$ stems from an order of magnitude larger density of states for holes in the lateral valence band maxima than for electrons in the conduction band minimum. We interpret the observed reentrant sign-alternating $\rho_{xy}(B)$ between electronic and hole conductivities and its zero resistivity state in the quantum Hall range of fields on the basis of a calculated picture of magnetic levels in a DQW.Comment: 15 pages, 13 figure

The peculiarities of ultrasound wave propagation in magnetorheological fluid with complex dispersive phase

This work is devoted to experimental study of the peculiarities of ultrasound wave propagation in magnetorheological fluid (MRF) with complex disperse phase under evaluation of changing of ultrasonic waves (UW) velocity in MRF on the base of water, oxide powder and carbonyl iron particles vs. intensity of applied magnetic field have been obtained. It was found that in the result of magnetic field separation the oxide layer thickness of MRF is increasing with the field value and can be determined by 2-3 µm and lesser

Quasi-ballistic transport in HgTe quantum-well nanostructures

The transport properties of micrometer scale structures fabricated from high-mobility HgTe quantum-wells have been investigated. A special photoresist and Ti masks were used, which allow for the fabrication of devices with characteristic dimensions down to 0.45 $\mu$m. Evidence that the transport properties are dominated by ballistic effects in these structures is presented. Monte Carlo simulations of semi-classical electron trajectories show good agreement with the experiment.Comment: 3 pages, 3 figures; minor revisions: replaced "inelastic mean free path" with "transport mean free path"; corrected typing errors; restructered most paragraphs for easier reading; accepted for publication in AP

Učinci probiotika koji sadrže Bacillus subtilis na crijevnu mikrofloru, kakvoću žutanjka i koncentracije lipida u krvi prepelica nesilica pasmine faraon

The current literature is not comprehensive concerning the influence of Bacillus subtilis on lipid metabolism, egg chemical characteristics, and intestinal microbiota of Japanese quail. The aim of this study was to evaluate the effects of a Bacillus subtilis strain on yolk quality, gut bacterial populations, and total cholesterol and triglyceride concentrations in the plasma of organically farmed Pharaon quail layers. Forty-five-day-old female quails were randomly distributed into four groups of 10 birds each: a no-treatment control group and three test groups receiving powder of Bacillus subtilis DSM 32424 at a minimum rate of 1 × 106 colony forming units per gram, dissolved in drinking water at doses of 50, 75 and 100 mg per kg body weight, daily during 30 days. The use of the probiotic at doses of 50 and 100 mg resulted in significantly reduced faecal staphylococci count on day 30 (P<0.05), while no significant changes were detected in lactobacilli or coliform bacteria. This study gives the first evidence of the influence of Bacillus subtilis on acid value and carotenoid levels in egg yolks laid by quails. Carotenoids were significantly elevated in the 75 mg group on day 30 (P<0.05), but significantly decreased in the 50 and 100 mg groups (P<0.05). Acidity, triglyceride and total cholesterol concentrations in quail serum were not affected significantly by the treatment throughout the study, though their values were reduced. The inclusion of Bacillus subtilis DSM 32424 in drinking water for laying Pharaon quails inhibited faecal staphylococci proliferation and enhanced yolk carotenoid content. Therefore, it can be proposed that including this probiotic in laying quail diets may have beneficial outcomes for both layers and the second generation.Ovaj rad nije sveobuhvatan obzirom na utjecaj Bacillus subtilis na metabolizam lipida, kemijska svojstva jaja te crijevne mikroorganizme japanskih prepelica. Istraživanje je obavljeno u svrhu procjene učinaka Bacillus subtilis soja na kakvoću žutanjka, populacije bakterija u crijevima uz ukupne koncentracije kolesterola i triglicerida u krvi organski uzgajanih prepelica nesilica pasmine faraon. Četrdesetpetodnevne ženke prepelice nasumice su podijeljene u četiri skupine od po 10 ptica: kontrolnu skupinu koja nije primala dodatak prehrani i tri pokusne skupine koje su primale prašak Bacillus subtilis DSM 32424 pri najmanjem postotku od 1 × 106 jedinica koje stvaraju koloniju po gramu, otopljen u pitkoj vodi u dozama od 50, 75 i 100 mg po kilogramu tjelesne težine, svakodnevno tijekom 30 dana. Uporaba probiotika u dozama od 50 i 100 mg rezultirala je značajnim smanjenjem količine fekalnih stafilokoka na 30. dan (P<0,05), dok značajnije promjene laktobacila i koliformnih bakterija nisu otkrivene. Ovo je istraživanje prvi put pokazalo utjecaj Bacillus subtilis na vrijednost kiseline i razine karotenoida u žutanjcima koje nesu prepelice. Karotenoidi su se značajno podigli na 30. dan u skupini koja je primala 75 mg (P<0,05), ali su se i značajno smanjili u skupinama koje su primale 50 i 100 mg (P<0,05). Terapija nije statistički značajno djelovala na kiselinu. Pokusni dodatak nije značajno utjecao niti na koncentracije triglicerida i ukupni kolesterol u krvi prepelica tijekom ispitivanja, premda su te koncentracije dosta smanjene. Na temelju dobivenih rezultata, zaključeno je da je dodavanje Bacillus subtilis DSM 32424 u pitku vodu za prepelice nesilice pasmine Faraon gotovo na svim proučavanim razinama inhibiralo proliferaciju fekalnih stafilokoka i povećalo udio karotenoida u žutanjku. Stoga se može reći da uključivanje probiotika u prehranu prepelica nesilica može imati korisni učinak i na nesilice i na drugu generaciju

Spatial and Wavenumber Resolution of Doppler Reflectometry

Doppler reflectometry spatial and wavenumber resolution is analyzed within the framework of the linear Born approximation in slab plasma model. Explicit expression for its signal backscattering spectrum is obtained in terms of wavenumber and frequency spectra of turbulence which is assumed to be radially statistically inhomogeneous. Scattering efficiency for both back and forward scattering (in radial direction) is introduced and shown to be inverse proportional to the square of radial wavenumber of the probing wave at the fluctuation location thus making the spatial resolution of diagnostics sensitive to density profile. It is shown that in case of forward scattering additional localization can be provided by the antenna diagram. It is demonstrated that in case of backscattering the spatial resolution can be better if the turbulence spectrum at high radial wavenumbers is suppressed. The improvement of Doppler reflectometry data localization by probing beam focusing onto the cut-off is proposed and described. The possibility of Doppler reflectometry data interpretation based on the obtained expressions is shown.Comment: http://stacks.iop.org/0741-3335/46/114

Electro-hydraulic generator of vibrations

Приведені результати експериментального дослідження двоканального електрогідравлічного генератора коливань. Показано, що у всьому діапазоні частот поршень гідравлічної коливальної системи здійснює стійкі коливальні рухи завдяки введенню в структуру генератора датчика стабілізації середнього положення привода. Підтверджено можливість регулювання амплітуди коливань вихідної ланки привода двома способами: безпосереднім регулюванням подачі насосної установки або за рахунок зміни величини керуючого сигналу, що подається на електрогідравлічний підсилювач від блоку керування.The results of experimental research of twochannel electro-hydraulic generator of vibrations are resulted. It is showed that in all of range of frequencies the piston of the hydraulic oscillating system carries out stable fluctuating motions due to introduction to the structure of generator of sensor of stabilizing of midposition there is a drive. Possibility of adjusting of amplitude of vibrations of output link is confirmed there is a drive two methods: direct adjusting of serve of the pumping setting or due to the change of size of managing signal which is given on an electro-hydraulic strengthener from the block of management.Приведены результаты экспериментального исследования двухканального электрогидравлического генератора колебаний. Показано, что во всем диапазоне частот поршень гидравлической колебательной системы осуществляет устойчивые колебательные движения благодаря введению в структуру генератора датчика стабилизации среднего положения привода. Подтверждена возможность регулировки амплитуды колебаний выходного звена привода двумя способами: непосредственным регулированием подачи насосной установки или за счет изменения величины управляющего сигнала, подаваемого на электрогидравлический усилитель от блока управления

Severe community-acquired pneumonia in adult patients managed in a general ward at a public hospital

Indexación: Web of Science; ScieloIntroducción: La neumonía grave del adulto adquirida en la comunidad (NAC grave) se caracteriza por requerir manejo en la unidad de cuidados intensivos (UCI), dado su mayor mortalidad y riesgo de complicaciones, por lo cual se han diseñado distintas escalas de predicción de gravedad. Objetivo: Identificar apacientes adultos con NAC grave manejados en la sala de cuidados generales. Pacientes y Métodos: Estudio clínico descriptivo retrospectivo, se revisaron las fichas clínicas de 131 pacientes adultos egresados del servicio de medicina del hospital de Quilpué con el diagnóstico de NAC entre el 1 de enero y 31 de diciembre del 2010. Se examinaron los criterios de NAC grave de la Sociedad de Tórax Americana (ATS) y se midió el CURB-65 de 89 pacientes que consignaban esta información. Resultados: En 16 pacientes (18%) se obtuvo una puntuación del CURB-65 ≥ 3 y en 8 pacientes (9%) se identificaron ≥ 3 criterios menores de la ATSy en 2 de ellos un criterio mayor. Conclusión: Se identificaron pacientes con NAC grave manejados en la sala de cuidados generales de un hospital publico.Introduction: Severe community-acquired pneumonia (severe CAP) is characterized by intensive care unit (ICU) requirement, given its higher mortality and complications rate. Different prediction scales have been designed to assess severity. Objective: Identify adult patients with severe CAP managed in the general ward of a public hospital. Patients and Methods: Retrospective descriptive study, including all adult patients dischargedfrom hospital with CAP diagnosis, from January 1st to December 31st, 2010, with a total of 131 medical records reviewed. The American Thoracic Society criteria (ATS) of severe CAP and CURB-65 scores from 89 medical records were calculated. Results: 16 patients (18%) had CURB-65 score ≥ 3, 8 patients (9%) had ≥ 3 minor ATS criteria, and 2 of those patients had a major criterion. Conclusion: A significant number of patients with severe CAP were managed on the general ward of a public hospital.http://www.scielo.cl/pdf/rcher/v29n1/art02.pd