Three ways of treating a linear delay differential equation

This work concerns the occurrence of Hopf bifurcations in delay differential equations (DDE). Such bifurcations are associated with the occurrence of pure imaginary characteristic roots in a linearized DDE. In this work we seek the exact analytical conditions for pure imaginary roots, and we compare them with the approximate conditions obtained by using the two variable expansion perturbation method. This method characteristically gives rise to a “slow flow” which contains delayed variables. In analyzing such approximate slow flows, we compare the exact treatment of the slow flow with a further approximation based on replacing the delayed variables in the slow flow with non-delayed variables, thereby reducing the DDE slow flow to an ODE. By comparing these three approaches we are able to assess the accuracy of making the various approximations. We apply this comparison to a linear harmonic oscillator with delayed self-feedback

Experimental investigation of the excess charge and time constant of minority carriers in the thin diffused layer of 0.1 ohm-cm silicon solar cells

An experimental method is presented that can be used to interpret the relative roles of bandgap narrowing and recombination processes in the diffused layer. This method involves measuring the device time constant by open-circuit voltage decay and the base region diffusion length by X-ray excitation. A unique illuminated diode method is used to obtain the diode saturation current. These data are interpreted using a simple model to determine individually the minority carrier lifetime and the excess charge. These parameters are then used to infer the relative importance of bandgap narrowing and recombination processes in the diffused layer

IN VITRO STUDY ON PROTEASE AND THROMBOLYTIC ACTIVITY OF AQUEOUS EXTRACT FROM LEUCAS ASPERA (L.) LEAVES

Objective: The current study is an attempt to screen for the in vitro clot lysis and proteolytic activity of aqueous extract of Leucas aspera leaves. Methods: Thrombolytic activity and protease activity of the crude enzyme obtained by ammonium sulfate precipitation and dialysis were assayed using blood clot and casein as substrates respectively. Native PAGE and gel documentation studies were performed to calculate the molecular weight of the enzyme. Results: In the study, 40% salt fractioned crude enzyme sample exhibited significant thrombolytic and caseinolytic activity. Further dose-dependent increased activity was observed with the maximum lytic activity of 52.11±1.04 % at 1 mg/ml of the sample when compared to the reference drug streptokinase (71.39±0.32%). Also, 68.72±0.62 U/hr of caseinolytic activity was observed for 1 mg/ml of the sample fraction. Conclusion: The study highlights and validates the efficacy of Leucas aspera leaves extract for thrombolytic and proteolytic actions. Enzyme with an approximate molecular weight, 19.89 KDa could be responsible for the significant lytic activity

Seasonal and Altitudinal Prevalence of Fascioliasis in Buffalo in Eastern Nepal

Buffalo is the most important livestock commodities for milk, meat production and several other multipurpose uses distributed densely from southern tarai to northern mid-hills in Nepal. Among several internal parasitic diseases fascioliasis is highly economic one caused by Fasciola in buffaloes. However, there are only few studies carried on prevalence of fascioliasis emphasizing buffaloes in relation to seasonal (summer and rainy, and winter) and altitudinal variations. Therefore, we examined prevalence of fascioliasis seasonally and vertically. For the purpose, we selected two districts of eastern Nepal and sampled from low altitude area known as Madhesha ranging from 175-200, Dhankuta from 800-1200 m, and Murtidhunga from 1800-2200 m elevation from the sea level, representing tarai, mid hills and high hills, respectively. Altogether from February 2013 to January 2014 at every two months interval we collected 798 fecal samples from buffaloes; 282 from Murtidhunga, 239 from Dhankuta and 277 from Madhesha. The samples were examined microscopically for the presence of Fasciola eggs using sedimentation technique. Results showed that overall prevalence of fascioliasis in buffaloes was 39.9% (319/798), ranging highest 42.6%in Madhesha followed by 39.7% in Murtidhunga and 37.2% in Dhankuta, respectively. The prevalence of fascioliasis was found to be significantly (p <0.05) high in winter (44.9%) comparing to rainy season (34.4%). The prevalence of fascioliasis in buffaloes was relatively higher in low altitude than high altitude, although it was not statistically significant (p <0.05). In our findings the female buffaloes showed higher prevalence for fascioliasis than in male. Since the fascioliasis in buffaloes is highly endemic, thus strategic deworming in high risk period is recommended along with measure to prevent pasture contamination with buffalo feces

The impact of COVID-19 on BAME populations: a systematic review of experiences and perspectives

Black, Asian, Minority Ethnic (BAME) populations have been disproportionately affected by COVID-19, having amongst the highest rates of infection and mortality. Additional risk factors for BAME populations include older age and living with poverty and deprivation. Information has emerged, but peer reviewed research and literature examining the experiences and/or perspectives of this most recent of diseases on BAME populations is fragmented and lacks coalescence. This systematic review will therefore bring together and integrate existing and emergent evidence around the experiences and/or perspectives of COVID-19 on BAME populations

THE PREVALENCE OF HYPOCALCAEMIA AMONG PATIENTS UNDERGOING THYROIDECTOMY AT A SOUTH INDIAN TERTIARY HOSPITAL: A PROSPECTIVE STUDY.

Background After total thyroidectomy, calcium levels drop temporarily and permanently. Parathyroid glands adjacent to the thyroid glands are important for calcium metabolism. An accidental parathyroid gland injury damages calcium metabolism. Surgery-related hypocalcemia may be observed 24-48 hours later. This research also attempts to uncover the biochemical and clinical causes of hypocalcemia. This research evaluates neuromuscular stability using Chvostek and Trousseau signs.  Method An observational study was conducted prospectively at JSS Hospital from Mysuru, Department of General Surgery. The patients undergoing total thyroidectomy were included in the study. the patients were thoroughly examined for their calcium levels after the surgery. Follow up were taken for 6 months if the calcium levels were less than 8 mg then it was classified as permanent hypocalcemia. The data for 100 patients was collected and then statistically analyzed for the occurrence of hypocalcemia.  Results It was found that the operating time (p = 0.03), indication (p = 0.001), and level of thyroid hormone (p = 0.03) can be correlated with the occurrence of hypocalcemia. Other factors, such as gender and age of the patient, could not be correlated to the occurrence of hypocalcemia as the p-value was not statistically significant. Conclusion After total thyroidectomy, the operating time, indication, and level of thyroid hormone can be correlated with the occurrence of hypocalcemia. Checking the calcium levels after 6 hours and 24 hours of the surgery and regular follow-up can prevent the worsening of hypocalcemia.  Recommendations This research highlights the importance of monitoring calcium levels following total thyroidectomy and identifies key factors, including operating time, indication, and thyroid hormone levels, that can contribute to hypocalcemia. To mitigate the risk of hypocalcemia, it is recommended to check calcium levels at specific post-operative intervals and establish a regular follow-up protocol for patients undergoing total thyroidectomy

Approximate Hermitian-Yang-Mills structures and semistability for Higgs bundles. II: Higgs sheaves and admissible structures

We study the basic properties of Higgs sheaves over compact K\"ahler manifolds and we establish some results concerning the notion of semistability; in particular, we show that any extension of semistable Higgs sheaves with equal slopes is semistable. Then, we use the flattening theorem to construct a regularization of any torsion-free Higgs sheaf and we show that it is in fact a Higgs bundle. Using this, we prove that any Hermitian metric on a regularization of a torsion-free Higgs sheaf induces an admissible structure on the Higgs sheaf. Finally, using admissible structures we proved some properties of semistable Higgs sheaves.Comment: 18 pages; some typos correcte