Designer quantum states on a fractal substrate: compact localization, flat bands and the edge modes

Compact localized single particle eigenstates on a deterministic fractal substrate, modelled by a triangular Sierpinski gasket of arbitrarily large size, are unravelled and examined analytically. We prescribe an exact real space renormalization group (RSRG) decimation scheme within a tight binding formalism to discern these states, and argue that the number of such states can be infinite if the fractal substrate is enlarged to its thermodynamic limit. Interestingly, these localized states turn out to populate the non-dispersive, flat bands in a periodic array of Sierpinski gasket motifs, however large they may be. Our results match and corroborate the recently observed compact localized, flat band states engineered on two dimensional photonic waveguide networks with a fractal geometry, and provide a whole subset of them, which, in principle, should be observable in fractal photonic lattice experiments

Gravitational deflection of light in the Schwarzschild -de Sitter space time

Recent studies suggest that the cosmological constant affects the gravitational bending of photons although the orbital equation for light in Schwarzschild-de Sitter space time is free from cosmological constant. Here we argued that the very notion of cosmological constant independency of photon orbit in the Schwarzschild-de Sitter space time is not proper. Consequently the cosmological constant has some clear contribution to the deflection angle of light rays. We stressed the importance of the study of photon trajectories from the reference objects in bending calculation, particularly for asymptotically non-flat space-time. When such an aspect is taken in to consideration the contribution of cosmological constant to the effective bending is found to depend on the distances of the source and the reference objects.Comment: 5 pages, no figur

Antibiotic usage pattern among inpatients of a paediatric ward in a tertiary care hospital in Eastern India

Background: The inevitable consequence of the widespread use of antimicrobial agents has been the emergence of antibiotic resistant pathogens. The rising incidence of bacterial resistance to common antibiotics, particularly, multi-drug resistant pneumococci, has prompted the need to use antibiotics judiciously in paediatric practice. The present study thus attempted to understand the antibiotic usage pattern among inpatients in a paediatric ward of a tertiary care hospital.Methods: A cross-sectional study was carried out for three months among the inpatients in the Department of Pediatrics in a tertiary care teaching hospital, Kolkata. The data regarding patient’s demographics and antibiotic use was collected daily in a pre-structured proforma. A descriptive statistical analysis of the data was performed.Results: A total of 124 patients were screened of which males and females represented 58.06% and 41.94% of the cases respectively with age group of 2-14 years presenting in majority. Among various causes of hospitalization, prevalence of respiratory disorders were maximum (25.81%), followed by hematological disorders (25%). Among various categories of prescribed drugs, antibiotics were found to be maximum (39.25%). Beta-lactum antibiotics were prescribed in majority (64.41%) with 56.91% being of cephalosporin group. The preferred route of administration was found to be parenteral (64%). 61.29 % cases were ordered laboratory investigations prior to the antimicrobial therapy initiation.  About 63.16% of the total samples for culture & sensitivity tested were reported positive. 39.58% of these positive cases showed resistance to empirical antibiotic therapy on lab reports.Conclusions: The study enables to obtain information on the antibiotic usage pattern in the pediatric population, focusing on prevalence of antibiotic misuse in our set-up and suggesting strategies of its minimization.

Dual versus conventional cardiac resynchronization: A pilot study

Background: Systolic heart failure treatment now includes cardiac resynchronization therapy (CRT) as a necessary element. CRT has been shown to have advantageous impacts on mortality, hospitalization rates, and quality of life. Approximately 30% of patients fail to respond to traditional CRT implantation. Aims and Objectives: This study aimed to compare the outcome of dual resynchronization by placing the right ventricular pacing lead at His bundle or left bundle branch area against conventional CRT. Materials and Methods: This longitudinal follow-up study of a total of 35 patients undergoing CRT device placement for assessment of safety, efficacy, and feasibility of the procedure and post-procedural complications and correlation with parameters obtained from electrocardiogram and echocardiography parameters in a tertiary care set up in India. Results: Among this matched population (mean age 64 years) there was a higher responder rate with the newer technique of dual resynchronization compared to conventional CRT (83% vs. 70%). Conclusion: Dual resynchronization therapy is feasible and safe and provides better electrical resynchronization compared to conventional CRT and could be a better alternative, especially when suboptimal electrical resynchronization is obtained

Analgesic Effect of Intrathecal Nalbuphine in Comparison with Fentanyl as an Adjuvant with Hyperbaric Bupivacaine (0.5%) during Spinal Anaesthesia in Lower Abdominal Surgery: A Double-blinded Randomised Clinical Study

Introduction: Local anaesthetics are sometimes added with intrathecal adjuvants. Nalbuphine is a synthetic agonistantagonist of opioid μ receptor. Fentanyl is a highly potent lipophilic synthetic opioid with rapid onset of action and it acts like morphine. It can be used during spinal anaesthesia for the purpose of decreasing the postoperative pain. Aim: To compare the safety and efficacy of preservative free intrathecal nalbuphine and fentanyl as additives to intrathecal hyperbaric bupivacaine (0.5%) for spinal anaesthesia. Materials and Methods: A randomised double-blinded clinical study was undertaken at Calcutta National Medical College and Hospital, Kolkata, West Bengal, India during March 2020 to August 2021 in which a total of 100 patients, belonging to American Society of Anaesthesiology (ASA) physical status I and II and undergoing elective lower abdominal surgery, were randomised into two equal group of 50 each. Group N received intrathecally 0.5 mg of nalbuphine with 3 mL (15 mg) of 0.5% hyperbaric bupivacaine, and group F received 25 µg of Fentanyl with 3 mL (15 mg) of 0.5% hyperbaric. Visual Analogue Scale (VAS) score, Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), Mean Arterial Pressure (MAP) and Heart Rate (HR) were recorded at varied intervals during intraoperative and postoperative period. Results: Significantly lower (p-value <0.001) mean VAS scores was observed beyond six hour of postoperative period in the group F. No significant changes (p-value >0.05) in SBP, DBP, MAP and HR were there between the groups. Few adverse effects like (hypotension, nausea, vomiting) were observed more in the fentanyl group which was statistically insignificant (p-value >0.05). Conclusion: Intrathecal fentanyl as compared to nalbuphine produces a significant postoperative analgesia when administered as an adjuvant with hyperbaric bupivacaine in cases of lower abdominal surgery

Effect of crenellation on different semen characteristics of cattle

The present study was conducted to study the crenellation patterns of semen and their relation with different seminal characteristics and post-thaw motility. Dried semen samples were classified into 6 grades (A1, A2, B1, B2, C1 and C2) based on the crenellation patterns. The study showed that breeds/strains had highly significant (P< 0.01) effect on different seminal traits. Significant (P< 0.05) effect of month of collection on sperm concentration and post- thaw motility was also observed. Crenellation patterns had highly significant (P< 0.01) effect on sperm concentration, initial motility and post-thaw motility. Sperm concentration, Initial motility and post-thaw motility was superior in A1, A2 and B1 grade and inferior in C1 and C2. B2 grade was of intermediate quality semen. A1, A2 and B1 grade ejaculates gave best post-thaw motility after cryopreservation. Poor post-thaw motility was found in C1, C2 and B2 grade ejaculates. Thus the crenellation can be effectively used as an indicator for simple and quick evaluation of semen quality in any semen laboratory as well as, at field level

Diving below the spin-down limit:constraints on gravitational waves from the energetic young pulsar PSR J0537-6910

We present a search for continuous gravitational-wave signals from the young, energetic X-ray pulsar PSR J0537-6910 using data from the second and third observing runs of LIGO and Virgo. The search is enabled by a contemporaneous timing ephemeris obtained using NICER data. The NICER ephemeris has also been extended through 2020 October and includes three new glitches. PSR J0537-6910 has the largest spin-down luminosity of any pulsar and is highly active with regards to glitches. Analyses of its long-term and inter-glitch braking indices provided intriguing evidence that its spin-down energy budget may include gravitational-wave emission from a time-varying mass quadrupole moment. Its 62 Hz rotation frequency also puts its possible gravitational-wave emission in the most sensitive band of LIGO/Virgo detectors. Motivated by these considerations, we search for gravitational-wave emission at both once and twice the rotation frequency. We find no signal, however, and report our upper limits. Assuming a rigidly rotating triaxial star, our constraints reach below the gravitational-wave spin-down limit for this star for the first time by more than a factor of two and limit gravitational waves from the l = m = 2 mode to account for less than 14% of the spin-down energy budget. The fiducial equatorial ellipticity is limited to less than about 3 x 10⁻⁵, which is the third best constraint for any young pulsar

Search for continuous gravitational wave emission from the Milky Way center in O3 LIGO--Virgo data

We present a directed search for continuous gravitational wave (CW) signals emitted by spinning neutron stars located in the inner parsecs of the Galactic Center (GC). Compelling evidence for the presence of a numerous population of neutron stars has been reported in the literature, turning this region into a very interesting place to look for CWs. In this search, data from the full O3 LIGO--Virgo run in the detector frequency band $[10,2000]\rm~Hz$ have been used. No significant detection was found and 95$\%$ confidence level upper limits on the signal strain amplitude were computed, over the full search band, with the deepest limit of about $7.6\times 10^{-26}$ at $\simeq 142\rm~Hz$. These results are significantly more constraining than those reported in previous searches. We use these limits to put constraints on the fiducial neutron star ellipticity and r-mode amplitude. These limits can be also translated into constraints in the black hole mass -- boson mass plane for a hypothetical population of boson clouds around spinning black holes located in the GC.Comment: 25 pages, 5 figure

GWTC-2.1: Deep extended catalog of compact binary coalescences observed by LIGO and Virgo during the first half of the third observing run

The second Gravitational-Wave Transient Catalog, GWTC-2, reported on 39 compact binary coalescences observed by the Advanced LIGO and Advanced Virgo detectors between 1 April 2019 15 ∶ 00 UTC and 1 October 2019 15 ∶ 00 UTC. Here, we present GWTC-2.1, which reports on a deeper list of candidate events observed over the same period. We analyze the final version of the strain data over this period with improved calibration and better subtraction of excess noise, which has been publicly released. We employ three matched-filter search pipelines for candidate identification, and estimate the probability of astrophysical origin for each candidate event. While GWTC-2 used a false alarm rate threshold of 2 per year, we include in GWTC-2.1, 1201 candidates that pass a false alarm rate threshold of 2 per day. We calculate the source properties of a subset of 44 high-significance candidates that have a probability of astrophysical origin greater than 0.5. Of these candidates, 36 have been reported in GWTC-2. We also calculate updated source properties for all binary black hole events previously reported in GWTC-1. If the eight additional high-significance candidates presented here are astrophysical, the mass range of events that are unambiguously identified as binary black holes (both objects ≥ 3 M⊙ ) is increased compared to GWTC-2, with total masses from ∼ 14 M ⊙ for GW190924_021846 to ∼ 182 M⊙ for GW190426_190642. Source properties calculated using our default prior suggest that the primary components of two new candidate events (GW190403_051519 and GW190426_190642) fall in the mass gap predicted by pair-instability supernova theory. We also expand the population of binaries with significantly asymmetric mass ratios reported in GWTC-2 by an additional two events (the mass ratio is less than 0.65 and 0.44 at 90% probability for GW190403_051519 and GW190917_114630 respectively), and find that two of the eight new events have effective inspiral spins χeff > 0 (at 90% credibility), while no binary is consistent with χeff < 0 at the same significance. We provide updated estimates for rates of binary black hole and binary neutron star coalescence in the local Universe