Dynamics of a single exciton in strongly correlated bilayers

We formulated an effective theory for a single interlayer exciton in a bilayer quantum antiferromagnet, in the limit that the holon and doublon are strongly bound onto one interlayer rung by the Coulomb force. Upon using a rung linear spin wave approximation of the bilayer Heisenberg model, we calculated the spectral function of the exciton for a wide range of the interlayer Heisenberg coupling \alpha=J_{\perp}/Jz. In the disordered phase at large \alpha, a coherent quasiparticle peak appears representing free motion of the exciton in a spin singlet background. In the N\'{e}el phase, which applies to more realistic model parameters, a ladder spectrum arises due to Ising confinement of the exciton. The exciton spectrum is visible in measurements of the dielectric function, such as c-axis optical conductivity measurements.Comment: 28 pages, 12 figure

Space--time fluctuations and the spreading of wavepackets

Using a density matrix description in space we study the evolution of wavepackets in a fluctuating space-time background. We assume that space-time fluctuations manifest as classical fluctuations of the metric. From the non-relativistic limit of a non-minimally coupled Klein-Gordon equation we derive a Schr\"odinger equation with an additive gaussian random potential. This is transformed into an effective master equation for the density matrix. The solutions of this master equation allow to study the dynamics of wavepackets in a fluctuating space-time, depending on the fluctuation scenario. We show how different scenarios alter the diffusion properties of wavepackets.Comment: 11 page

Digital dermoscopy to determine skin melanin index as an objective indicator of skin pigmentation

Clinical assessment of skin photosensitivity is subjectively determined by erythema and tanning responses to sunlight recalled by the subject, alternatively known as Fitzpatrick Skin Phototype (SPT). Responses may be unreliable due to recall bias, subjective bias by clinicians and subjects, and lack of cultural sensitivity of the questions. Analysis of red-green-blue (RGB) color spacing of digital images may provide an objective determination of SPT. This paper presents the studies to assess the melanin index (MI), as determined by RGB images obtained by both standard digital camera as well as by videodermoscope, and to correlate the MI with SPT based upon subjects' verbal responses to standardized questions administered by a dermatologist. A sample of subjects representing all SPTs I–VI was selected. Both the digital camera and videodermoscope were calibrated at standard illumination, light source and white balance. Images of constitutive skin of the upper ventral arm were taken of each subject using both instruments. The studies showed that 58 subjects (20 M, 38 F) were enrolled in the study (mean age: 47 years; range: 20–89), stratified to skin phototype I–VI. MI obtained by using both digital camera and videodermoscope increased significantly as the SPT increased (p = 0.004 and p &lt; 0.0001, respectively) and positively correlated with dermatologist-assessed SPT (Spearman correlation, r = 0.48 and r = 0.84, respectively). Digital imaging can quantify melanin content in order to quantitatively approximate skin pigmentation in all skin phototypes including Type VI skin. This methodology holds promise as a simple, non-invasive, rapid and objective approach to reliably determine skin phototype and, with further investigation, may prove to be both practical and useful in the prediction of skin cancer risk.</p

Monitoring of heart failure: comparison of left atrial pressure with intrathoracic impedance and natriuretic peptide measurements in an experimental model of ovine heart failure

Monitoring of HF (heart failure) with intracardiac pressure, intrathoracic impedance and/or natriuretic peptide levels has been advocated. We aimed to investigate possible differences in the response patterns of each of these monitoring modalities during HF decompensation that may have an impact on the potential for early therapeutic intervention. Six sheep were implanted with a LAP (left atrial pressure) sensor and a CRT-D (cardiac resynchronization therapy defibrillator) capable of monitoring impedance along six lead configuration vectors. An estimate of ALAP (LAP from admittance) was determined by linear regression. HF was induced by rapid ventricular pacing at 180 and 220 bpm (beats/min) for a week each, followed by a third week with daily pacing suspensions for increasing durations (1–5 h). Incremental pacing induced progressively severe HF reflected in increases in LAP (5.9 ± 0.4 to 24.5 ± 1.6 mmHg) and plasma atrial (20 ± 3 to 197 ± 36 pmol/l) and B-type natriuretic peptide (3.7 ± 0.7 to 32.7 ± 5.4 pmol/l) (all P<0.001) levels. All impedance vectors decreased in proportion to HF severity (all P<0.001), with the LVring (left ventricular)-case vector correlating best with LAP (r2=0.63, P<0.001). Natriuretic peptides closely paralleled rapid acute changes in LAP during alterations in pacing (P<0.001), whereas impedance changes were delayed relative to LAP. ALAP exhibited good agreement with LAP. In summary, impedance measured with an LV lead correlates significantly with changes in LAP, but exhibits a delayed response to acute alterations. Natriuretic peptides respond rapidly to acute LAP changes. Direct LAP, impedance and natriuretic peptide measurements all show promise as early indicators of worsening HF. ALAP provides an estimate of LAP that may be clinically useful

Anthracycline-Induced Cardiotoxicity: Cardiac Monitoring by Continuous Wave-Doppler Ultrasound Cardiac Output Monitoring and Correlation to Echocardiography

Background: Anthracyclines are agents with a well-known cardiotoxicity. The study sought to evaluate the hemodynamic response to an anthracycline using real-time continuous-wave (CW)-Doppler ultrasound cardiac output monitoring (USCOM) and echocardiography in combination with serum biomarkers. Methods: 50 patients (26 male, 24 female, median age 59 years) suffering from various types of cancer received an anthracycline-based regimen. Patients' responses were measured at different time points (T0 prior to infusion, T1 6 h post infusion, T2 after 1 day, T3 after 7 days, and T4 after 3 months) with CW-Doppler ultrasound (T0-T4) and echocardiography (T1, T4) for hemodynamic parameters such as stroke volume (SV; SVUSCOM ml) and ejection fraction (EF; EFechocardiography%) and with NT-pro-BNP and hs-Troponin T (T0-T4). Results: During the 3-month observation period, the relative decrease in the EF determined by echocardiography was -2.1% (Delta T0-T4, T0 71 +/- 7.8%, T4 69.5 +/- 7%, p = 0.04), whereas the decrease in SV observed using CW-Doppler was -6.5% (Delta T0-T4, T0 54 +/- 19.2 ml, T4 50.5 +/- 20.6 ml, p = 0.14). The kinetics for serum biomarkers were inversely correlated. Conclusions: Combining real-time CW-Doppler USCOM and serum biomarkers is feasible for monitoring the immediate and chronic hemodynamic changes during an anthracycline-based regimen; the results obtained were comparable to those from echocardiography

Аліментні обов'язки інших членів сім'ї та родичів

Виявлено проблеми у врегулюванні аліментних обов’язків інших членів сім’ї та родичів, вироблено рекомендації щодо їх вирішення. Проаналізовано специфіку правового регулювання аліментних зобов’язань зазначених суб’єктів, сімейне законодавство та міжнародний досвід. Ключові слова: аліментні обов’язки, правове регулювання, сімейне законодавство.Выявлены проблемы в урегулировании алиментных обязанностей других членов семьи и родственников, выработаны рекомендации по их решению. Проанализирована специфика правового регулирования алиментных обязательств указанных субъектов, семейное законодательство и международный опыт. Ключевые слова: алиментные обязанности, правовое регулирование, семейное законодавствоThis article is dedicated to identifying problems in the regulation of the alimentary obligations of other family members and relatives, and to making recommendations and proposing solutions. Studing the specificity of the legal regulation of alimentary obligations of these entities, analysing the current family law and international experience are very important. Key words: alimentary obligations, legal regulation, family law

Case Report: A Truck Driver with Pelvic Pain

Extraskeletal myxoid chondrosarcoma (EMC) is a relatively rare soft tissue malignancy, originally described in the 1950s and characterized as a distinct entity from chondrosarcoma of the bone in the 1970s. These tumors most commonly originate in the proximal extremities, and their occurrence in the genitourinary tract is exceedingly rare, with few case reports citing origination in its component organs. We present a clinical case report of an EMC originating from the base of the penis with significant local involvement of the bony pelvis