Pressure induced electronic topological transition in Sb2S3

Pressure induced electronic topological transitions in the wide band gap semiconductor Sb2S3 (Eg = 1.7-1.8 eV) with similar crystal symmetry (SG: Pnma) to its illustrious analog, Sb2Se3, has been studied using Raman spectroscopy, resistivity and the available literature on the x-ray diffraction studies. In this report, the vibrational and the transport properties of Sb2S3 have been studied up to 22 GPa and 11 GPa, respectively. We observed the softening of phonon modes Ag(2), Ag(3) and B2g and a sharp anomaly in their line widths at 4 GPa. The resistivity studies also shows an anomaly around this pressure. The changes in resistivity as well as Raman line widths can be ascribed to the changes in the topology of the Fermi surface which induces the electron-phonon and the strong phonon-phonon coupling, indicating a clear evidence of the electronic topological transition (ETT) in Sb2S3. The pressure dependence of a/c ratio plot obtained from the literature showed a minimum at ~ 5 GPa, which is consistent with our high pressure Raman and resistivity results. Finally, we give the plausible reasons for the non-existence of a non-trivial topological state in Sb2S3 at high pressures.Comment: 24 pages, 6 Figures, 2 tables submitted for publicatio

Trawl fishery of the mid-shelf region off Mangalore coast

Trawl fishery over the mid-shelf region off Mangalore coast was studied during 1979/80,1987/88. Details of craft and gear employed, the nature and extent of fishing ground and the changing pattern of fishins are dealt with. There was an eight-fold increase in fishing effort from 4,132 unit days in 1979•80 to a maximum of 34,758 unit days in 1984•85. The annual production rose from 527 t in 1979-80 to a maximum of 10,327 t in ' 1986-87, showing a twenty-fold increase. The catch rate, however, showed an increasing trend initially reaching a peak value of 299 kg in 1981 -82 and declined thereafter only to register another peak of 335 kg in 1985-86

Fishery, biology and population dynamics of Nemipterus japonicus (Bloch) off Visakhapatnam

Threadfin breams formed 9% of the total small trawler catches of Visakhapatnam, Nemipterus mesoprion and N. japonicus being the dominant species. The estimated growth parameters for N. japonicus are L = 340 mm and K = 0.52 year-1. Size at first maturity is estimated as 128 mm. The species spawns during July to April with a peak in September. The mortality rate Z, F and M were 3.52, 2.41 and 1.11 respectively

Sciaenid fishery off Visakhapatnam with some aspects of population dynamics of Johnius carutta (Bloch)

The average annual catch of sciaenids by small-mechanized units operated off Visakhapatnam was 465 t, which formed 5.76% of the total landings. Of the thirteen species of sciaenids landed, Johnius carutta and Nibea maculata dominated the fishery. The estimated asymptotic length (L∝) and growth constant (K-year) of J. carutta were 295 mm and 0.40, respectively. The size at first maturity was 154 mm and the spawning season was during March - May. The mortality rates Z, F and M were 3.02, 2.05 and 0.97 respectively. The exploitation rate of 0.68 indicated heavy exploitation of the species. The yield/ recruit curves showed that the exploitation rate could be brought down to E max (0.57) without affecting the catch

Lizardfish fishery, biology and population dynamics of Saurida undosquamis (Richardson) off Visakhapatnam

The average annual estimated catch of lizardfishes off Visakhapatnam is 229 t, which formed 5.3% of the total landings during the period 1990-2001. Five species of lizardfishes are landed of which, Saurida undosquamis and S. tumbil are the dominant and contributed 88% to the total lizardfish landings of small trawlers. The fishery, biology and some aspects of population dynamics of S. undosquamis are studied. The estimated asymptotic length (L ) and growth constant (K) in S. undosquamis are 395 mm and 0.31 year –1 respectively. The fish attained maturity at 230 mm, with spawning period extending from October to March. The estimated mortality rates Z, F, and M in the species are 1.81, 1.05 and 0.76 respectively. The exploitation rate (E) of S.undosquamis is 0.58

First mesospheric turbulence study using coordinated rocket and MST radar measurements over Indian low latitude region

A campaign to study turbulence in the mesosphere, over low latitudes in India, using rocket-borne measurements and Indian MST radar, was conducted during July 2004. A rocket-borne Langmuir probe detected a spectrum of electron density irregularities, with scale sizes in the range of about 1m to 1 km, in 67.5-78.0 km and 84-89 km altitude regions over a low latitude station Sriharikota (13.6°N, 80.2°E). A rocket-borne chaff experiment measured zonal and meridional winds about 30 min after the Langmuir probe flight. The MST radar located at Gadanki (13.5°N, 79.2°E), which is about 100 km west of Sriharikota, also detected the presence of a strong scattering layer in 73.5-77.5 km region from which radar echoes corresponding to 3m irregularities were received. Based on the region of occurrence of irregularities, which was highly collisional, presence of significant shears in zonal and meridional components of wind measured by the chaff experiment, 10 min periodicity in zonal and meridional winds obtained by the MST radar and the nature of wave number spectra of the irregularities, it is suggested that the observed irregularities were produced through the neutral turbulence mechanism. The percentage amplitude of fluctuations across the entire scale size range showed that the strength of turbulence was stronger in the lower altitude regions and decreased with increasing altitude. It was also found that the amplitude of fluctuations was large in regions of steeper electron density gradients. MST radar observations showed that at smaller scales of turbulence such as 3 m, (a) the thickness of the turbulent layer was between 2 and 3 km and (b) and fine structures, with layer thicknesses of about a km or less were also embedded in these layers. Rocket also detected 3-m fluctuations, which were very strong (a few percent) in lower altitudes (67.5 to 71.0 km) and small but clearly well above the noise floor at higher altitudes. Rocket and radar results also point to the possibility of existence of thin layers of turbulence (<450 m). The turbulence parameters estimated from rocket-borne measurements of electron density fluctuations are consistent with those determined from MST radar observed Doppler spectra and the earlier works

Evaluation of electrocardiographic and serum biochemical changes in arrhythmias associated with renal diseases of dogs

The present study was conducted to investigate electrocardiographical (ECG) and haemato-biochemical changes in arrhythmia associated with renal diseases in dogs. The dogs with renal affections confirmed through appropriate diagnostic methods were selected and screened for arrhythmia. The ECG and haemato-biochemical parameters of twenty dogs with arrhythmia were compared with that of the control group and ECG parameters were statistically correlated with the haemato-biochemical parameters for correlation studies. It was found that the occurrence of arrhythmia was 51.2 per cent in renal diseases. Arrhythmia was more predominant in dogs with chronic kidney disease (CKD) followed by acute kidney injury (AKI). Sinus arrhythmia followed by first-degree AV block and wandering pacemaker were the common types of arrhythmias observed. A significant increase in R-R interval and a decrease in heart rate was noticed in comparison. The haemato-biochemical analysis revealed anaemia, leukocytosis with neutrophilia, elevated blood urea nitrogen (BUN), creatinine and magnesium level. A significant positive correlation was noticed between haemoglobin, volume of packed red cells (VPRC) and red blood cell count (RBC) with T amplitude and, creatinine and BUN levels with corrected Q-T interval. A significant negative correlation was noticed between VPRC, RBC and haemoglobin with the corrected QT interval. The present study revealed ECG and haemato-biochemical parameters had a significant role in renal diseases in dogs which might help in the early diagnosis and proper management of arrhythmia associated with renal diseases

Variability in soil properties influencing pigeonpea (Cajanus cajana L.) yield: a multivariate statistical analysis [version 3; peer review: 2 approved]

Aims: The aim of the study was to reveal the variability in soil properties influencing pigeonpea (Cajanus cajana L.) seed yield under semi-arid rainfed condition. Methods: Soils were initially classified into series level and further these series were divided into soil-phase units. For two site years viz., 2018-19 and 2019-20, surface soil samples from each soil-phase unit were collected before sowing of pigeonpea and subsequently crop growth parameters at critical stages were recorded. Results: The principal component analysis with varimax rotation resulted in seven components for both the site years, having eigenvalues greater than one, explained more than 80% of the variability. The step wise linear regression analysis showed that the pigeonpea seed yield was linearly correlated with PC3 (p<0.01), PC4 (p<0.01) and PC7 (p<0.05) of soil properties with R2 = 0.679, during 2018-19. Whereas, during 2019-20, the seed yield was linearly correlated with PC1 (p<0.01), PC3 (p<0.01) and PC6 (p<0.05) with R2 = 0.677. In site year 1, the available P2O5, Fe, Zn, S, Cu, number of pods, surface soil moisture determined the yield. In site year 2, the available K2O, P2O5, Fe, Zn, S, clay, CEC and available water content determined the yield. All these variables together explain variability in yield