Energy levels of a parabolically confined quantum dot in the presence of spin-orbit interaction

We present a theoretical study of the energy levels in a parabolically confined quantum dot in the presence of the Rashba spin-orbit interaction (SOI). The features of some low-lying states in various strengths of the SOI are examined at finite magnetic fields. The presence of a magnetic field enhances the possibility of the spin polarization and the SOI leads to different energy dependence on magnetic fields applied. Furthermore, in high magnetic fields, the spectra of low-lying states show basic features of Fock-Darwin levels as well as Landau levels.Comment: 6 pages, 4 figures, accepted by J. Appl. Phy

Instrumentation of a high-sensitivity microwave vector detection system for low-temperature applications

We present the design and the circuit details of a high-sensitivity microwave vector detection system, which is aiming for studying the low-dimensional electron system embedded in the slots of a coplanar waveguide at low temperatures. The coplanar waveguide sample is placed inside a phase-locked loop; the phase change of the sample may cause a corresponding change in the operation frequency, which can be measured precisely. We also employ a double-pulse modulation on the microwave signals, which comprises a fast pulse modulation for gated averaging and a slow pulse modulation for lock-in detection. In measurements on real samples at low temperatures, this system provides much better resolutions in both amplitude and phase than most of the conventional vector analyzers at power levels below -65 dBm.Comment: 7 pages, 11 figures, 1 table, lette

A Case of Reactive Cervical Lymphadenopathy with Fat Necrosis Impinging on Adjacent Vascular Structures.

A tender neck mass in adults can be a diagnostic challenge due to a wide differential diagnosis, which ranges from reactive lymphadenopathy to malignancy. In this report, we describe a case of a young female with an unusually large and tender reactive lymph node with fat necrosis. The diagnostic imaging findings alone mimicked that of scrofula and malignancy, which prompted a complete workup. Additionally, the enlarged lymph node was compressing the internal jugular vein in the setting of oral contraceptive use by the patient, raising concern for Lemierre's syndrome or internal jugular vein thrombosis. This report shows how, in the appropriate clinical context, and especially with the involvement of adjacent respiratory or neurovascular structures, aggressive diagnostic testing can be indicated

Analytical Solution to Transport in Brownian Ratchets via Gambler's Ruin Model

We present an analogy between the classic Gambler's Ruin problem and the thermally-activated dynamics in periodic Brownian ratchets. By considering each periodic unit of the ratchet as a site chain, we calculated the transition probabilities and mean first passage time for transitions between energy minima of adjacent units. We consider the specific case of Brownian ratchets driven by Markov dichotomous noise. The explicit solution for the current is derived for any arbitrary temperature, and is verified numerically by Langevin simulations. The conditions for vanishing current and current reversal in the ratchet are obtained and discussed.Comment: 4 pages, 3 figure

Effect of Increasing Stocking Density on Performance and Heterophil/Lymphocyte Ratios in Broilers

An experiment on space allowance of 0.095, 0.071, 0.057 and 0.048 m2/bird on wire mesh cages was conducted to study their effects on live-weight, feed intake and feed conversion of Orgal broilers from the age of 4 to 10 weeks. Heterophil/lymphocyte (H/L) ratio,an indicator of stress was also studied to determine whether over-crowding would effect this ratio. During the first 2 weeks of the experiment increasing stocking is reduced feed intake and improve feed conversion without significantly affecting growth rate. Overall, birds on the most liberal floor space allowance (0.095 m2/bird) had the best growth rate (39.2 glda») but this was achieved at a significantly higher feed intake (127.9 g/day) and poorer feed conversion (3.3).Conversely, birds on the highest stocking density (0.048 ,rz2lbiTd) had the poorest performance in terms of growlh rate (32.2 g/day) and feed intake(90.6 g/day). Birds on the two higher stocking density were constantly under stress as indicated by their relatively high H/L. ratios from the fourth week, of the study onwards, these two treatments also had higher mortalities. The results of the present study showed that stress associated with overcrowding reduced performance in broilers. A space allowance of 0.071 m2/bird is sufficient under om- local conditions for broiled reared in raised floor cages

Management of an acute intracranial emergency in pregnancy

We report a case of a mid-20s primigravida at 37 weeks' gestation who presented with severe headache and acute neurological deterioration. The CT brain scan showed hydrocephalus caused by a colloid cyst in the third ventricle. The patient underwent emergency placement of an external ventricular drain for decompression of acute hydrocephalus. Four hours later, labour commenced spontaneously, and in view of her neurological status, a decision was taken to perform a caesarean section under general anaesthetics. Four days postpartum, the patient underwent an endoscopic removal of the cyst. Intracranial emergencies during pregnancy are rare and challenging to manage. The mortality rate can be significant. Diagnostic and surgical intervention should not be delayed because of pregnancy. An individualised treatment approach is required with multidisciplinary input. The collaborative efforts of our multidisciplinary team resulted in prompt diagnosis and surgical treatment in this case that resulted in both a healthy mother and child.</p