Pair Of Bands Research Articles

Insights into vertebral band pair deposition rate in the juvenile common thresher shark (Alopias vulpinus) in the northeastern Pacific Ocean.

Validation of band pair deposition rates in elasmobranch vertebrae is essential for accurate age estimation using band pair counting techniques. We present a validation study of the vertebral band pair deposition rate for juvenile common thresher sharks Alopias vulpinus in the northeastern Pacific Ocean (NEPO) using tag and recapture with oxytetracycline (OTC) injection. A total of 14 juvenile A. vulpinus marked with OTC from 1998 through 2013 were recaptured with times at liberty ranging from 1.08 to 3.81 years with an average of 2.14 years (±0.97 years standard deviation, SD). Shark size ranged from 80 to 128 cm fork length (LF) at the time of OTC injection and from 112 to 168 cm LF for those measured at recapture. The slopes of the relationships between band pairs post OTC and years at liberty for each reader ranged from 0.84 to 0.95, slightly lower than the 1.0 slope expected from annual band pair formation. These findings preliminarily support previous age and growth assumptions based on a one band pair per year deposition rate. However, high variation in band pair deposition rates between samples, coupled with regression slopes falling just under one band pair per year, indicates that further investigation is needed to refine band pair deposition rate estimates.

Revealing Their True Stripes: Mg/Ca Banding in the Paleogene Planktonic Foraminifera GenusMorozovellaand Implications for Paleothermometry

AbstractThe Mg/Ca ratio of foraminiferal calcite is a widely used empirical proxy for ocean temperature. Foraminiferal Mg/Ca‐temperature relationships are based on extant species and are species‐specific, introducing uncertainty when applying them to the fossil tests of extinct groups. Many modern species show remarkable heterogeneity in their intra‐test Mg distributions, typically due to the presence of high Mg bands, which have a biological origin. Importantly, banding patterns differ between species, which could affect Mg/Ca‐temperature relationships. Few studies have looked at intra‐test variability in Mg/Ca ratios in extinct species of foraminifera, despite the obvious implications for paleothermometry. We used electron probe microanalysis (EPMA) to investigate intra‐test Mg distributions in the fossil tests of two species of planktonic foraminifera from the extinct muricate mixed‐layer‐dwelling genusMorozovella, commonly used in Paleogene sea surface temperature reconstructions. BothM.aragonensisandM.cratershow striking Mg banding patterns with multiple high and low Mg/Ca band pairs throughout the test wall in all chambers. The intra‐test Mg variability inM.aragonensisandM.crateris similar to that in modern species widely used in paleoclimate reconstructions and banding patterns are consistent with published growth models for modern forms, albeit with subtle differences. The presence of Mg bands supports the application of Mg/Ca‐palaeothermometry in extinctMorozovellaspecies as well as the utility of EPMA for examining preservation of foraminifera tests in paleoclimatological studies. However, we emphasize the importance of rigorous assessments of inter‐ and intra‐test Mg variability when using microanalytical techniques for foraminiferal Mg/Ca paleothermometry.

Search for Super-Deformed Identical Bands in the A = 190 Mass Region on the Basis of Level Spin

The systematic study of Super-Deformed (SD) bands in the A=190 mass region has been performed. We observed a large number of pairs of SD bands, with different mass numbers, having transition energies nearly equal (within 3 keV) and having identical dynamic moments of inertia. The bands having nearly equal transitions energies and other parameters are called identical bands. We have performed detailed analysis and found 16 pairs of Super-Deformed Identical Bands (SDIBs) whose Eγ energies and moment of inertia are in good agreement with each other. The modified Variable Moment of Inertia (VMI) model is applied to 16 pairs of SDIBs to estimate the band spins by fitting the two parameters J0 and C. We found that out of 16 pairs, the band-head spin is consistent with moment of inertia and transition energies for four pairs. For another seven pairs, the transition energies and moment of inertia are identical, but originate from levels with different spins. The remaining five pairs have the identical energy but spins are either increasing or decreasing by one unit in the pair. Secondly, the NpNn scheme is applied to verify the existence of SDIBs. The parameters deduced from the NpNn scheme are also in good agreement for the mentioned case. The study indicates that each pair of conjugate nuclei have nearly identical spin, moment of inertia (dynamic) and gamma transition energy.

Empirically Driven multiwavelength K-corrections at low redshift

ABSTRACT K-corrections – a necessary ingredient for converting between flux in observed bands to flux in rest-frame bands – are critical for comparing galaxies at differing redshifts. These corrections often rely on fits to empirical or theoretical spectral energy distribution (SED) templates of galaxies. However, templates can only produce reliable K-corrections in regimes where SED models are robust. For instance, the templates utilized in some popular software packages are not well-constrained in some bands (e.g. WISE W4 in Kcorrect), which results in ill-behaved K-corrections. We address this shortcoming by developing an empirically driven approach to K-corrections that limits the dependence on SED templates. We perform a polynomial fit for the K-correction as a function of a galaxy’s rest-frame colour determined in a pair of well-constrained bands (e.g. 0(g − r)) and redshift, exploiting the fact that galaxy SEDs can be approximated as a one-parameter family at low redshift. For bands well-constrained by SED templates, our empirically driven K-corrections yield results comparable to the SED fitting methods used by Kcorrect and the GSWLC-M2 catalogue (the updated medium-deep GALEX–SDSS–WISE Legacy Catalogue). However, our method dramatically outperforms Kcorrect derived K-corrections for WISE W4. Our method is also robust to incorrect template assumptions outside of the optical bands and enforces that the K-correction must be zero at z = 0. Our K-corrected photometry and code are publicly available.

Unconventional hidden Rashba effects in two-dimensional InTe

Much attention has been paid to the hidden Rashba effect exhibiting an intriguing spin-layer locking phenomenon observed in two-dimensional materials with inversion symmetry. This effect provides a new possibility for manipulating Rashba spin polarization even in centrosymmetric materials. We propose a mechanism exhibiting an unconventional hidden Rashba effect showing a unique helical spin texture in which two Fermi circles in different bands have the same spin helicity exhibiting a complete spin separation in space. We demonstrate such an unconventional hidden Rashba effect by showing the unique electronic structures of two-dimensional InTe with inversion symmetry investigated by the first-principles calculations. It is found that spins in both the inner and outer bands with the one helicity are located in the top sublayer whereas spins with the other helicity are in the bottom sublayer indicating a complete spatial spin separation. Strong spin-orbit coupling and a band inversion among two pairs of spin-degenerate bands are the main origins for the unconventional hidden Rashba involving two pairs of spin-degenerate bands rather than one pair, which gets usually involved in the conventional (hidden) Rashba effects. This new type of the hidden Rashba effect observed in two-dimensional InTe would broaden our understanding of the underlying physics of spin polarization phenomena eventually leading to a potential application in future spintronics.

Slow Gamma Oscillations in the Mouse Olfactory Bulb are Correlated with Sniffing in the Dark Period

Neural activity in the olfactory bulb is reflected in local field potentials (LFPs). Functionally, LFPs in the olfactory bulb are categorized into different frequency bands: 1-4 Hz, 6-12 Hz, 25-50 Hz, and 65-130 Hz, which respectively correspond to respiration, sniffing, slow gamma, and fast gamma oscillations. While gamma oscillations in the olfactory bulb are modulated by respiration and sniffing, it remains unknown how and whether the modulation of LFP oscillations is affected by the time of day. To address this question, we recorded LFPs in the olfactory bulb, hippocampus, and neocortex of unrestrained mice for up to 3 d. For each recording site, we calculated the correlation coefficients of normalized LFP powers between pairs of frequency bands in the three regions during the dark and light periods. We then compared these correlations with those generated by surrogate data to investigate whether the correlation was statistically significant. We found that the correlation between sniffing and slow gamma oscillations was higher in the dark period than in the light period. Our finding has the potential to shed light on the coding scheme of olfactory information that is dependent on the light/dark cycle.

Abstract 29: Detection of Protein Kinase C Isoenzymes in Patients at Risk of Schistosoma Haematobium Induced Bladder Cancer

Abstract Purpose: The Detection of Protein Kinase C Isoenzymes in Patients at risk of Schistosoma haematobium induced Bladder Cancer attending University of Maiduguri Teaching Hospital (UMTH) was carried out. The study comprised of fifty six (56) patients aged ten to fifty six (10-56) years with clinical features of schistosomiasis and confirmed for the presence of S .haematobium eggs in urine samples. Methods: Twenty milliliters (20ml) of urine was centrifuged at 1000 rpm for 10 min to obtain the sediment. The supernatants were then discarded and the sediment (pellet) re-suspended for S. haematobium. A drop of the sediment were transferred to a glass slide, covered with a cover slip and examined using × 40 objective lens. The urine samples were observed for red blood cells and deposits that might contain proteins. The extraction of total urine template RNA was carried out according to Bioneer Specification and protocol; fifty six (56) of the S. haematobium samples of the patients were used. AccuPrep® Universal RNA Extraction Kit (K-3141) from Bioneer Corporation was used and one page protocol was followed for RNA Extraction. Pre- Denaturation was done for 5min at 94oC, Denaturation for 30sec at 94oC, Annealing for 30sec at 52oC, Extension for 1min at 72oC 35 cycles, Final extension for 5min at 72oC. Results: Result was run on 2% agarose gel. The study was able to investigate and detect the putative involvement of different PKC isoforms (alpha, beta, and delta) in patient with risk of schistosoma related bladder cancer. Out of the fifty six (56) Multiplex PCR Amplification of PKC Alpha, PKC Beta and PKC Delta from cDNA of extracted RNA template of S. haematobium infected urine sample investigated, only twenty seven (27) showed detection base pairs predicted size from Lane 1-9; of which PKC Alpha (325bp) has two (2) lane; PKC Beta (490bp) has seven (7) lane; and PKC Delta (404bp) has eighteen (18) lane of predicted base pair according to the cDNA size marker, some empty-zero (0) bands lanes and Unpredicted base pair band size were also seen. Conclusion: The major findings in the present study were the detection of PKC isoenzymes base pairs (band) which indicated the risk level of schistoma induced bladder cancer and stages of the patients using the analysis that proves Isoenzymes are detected by electrophoresis. Snail control, sanitation, avoid contacts with bullinus species and focus on early detection and diagnosis of patients infected with S. haematobium. Citation Format: Zanna Abdulsalam, Adamu Inuwa, Sambo Bello Zailani. Detection of Protein Kinase C Isoenzymes in Patients at Risk of Schistosoma Haematobium Induced Bladder Cancer [abstract]. In: Proceedings of the 11th Annual Symposium on Global Cancer Research; Closing the Research-to-Implementation Gap; 2023 Apr 4-6. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(6_Suppl):Abstract nr 29.

Critical behavior and exchange splitting in the two-dimensional antiferromagnet Mn on Re(0001)

We investigated the temperature-dependent electronic structure of the antiferromagnetic fcc-monolayer Mn on Re(0001) using vacuum-ultraviolet momentum microscopy. At $T=25$ K the collinear, row-wise antiferromagnetic phase of the Mn monolayer results in a spin splitting of states. Density-functional theory, being in good agreement with the experimental results, reveals the spin and orbital projection of the observed electronic bands. The exchange split bands shift in opposite directions with increasing temperature, decreasing the exchange splitting of a pair of itinerant bands from $280\ifmmode\pm\else\textpm\fi{}10$ meV at 25 K down to $185\ifmmode\pm\else\textpm\fi{}10$ meV at the N\'eel temperature ${T}_{\text{N}}=75\ifmmode\pm\else\textpm\fi{}5$ K. The exchange splitting remains constant for $T>{T}_{\text{N}}$. The persisting exchange splitting is attributed to a remaining short-range, fluctuating antiferromagnetic order far above ${T}_{\text{N}}$.

Previously uncharacterized rectangular bacterial structures in the dolphin mouth

Much remains to be explored regarding the diversity of uncultured, host-associated microbes. Here, we describe rectangular bacterial structures (RBSs) in the mouths of bottlenose dolphins. DNA staining revealed multiple paired bands within RBSs, suggesting the presence of cells dividing along the longitudinal axis. Cryogenic transmission electron microscopy and tomography showed parallel membrane-bound segments that are likely cells, encapsulated by an S-layer-like periodic surface covering. RBSs displayed unusual pilus-like appendages with bundles of threads splayed at the tips. We present multiple lines of evidence, including genomic DNA sequencing of micromanipulated RBSs, 16S rRNA gene sequencing, and fluorescence in situ hybridization, suggesting that RBSs are bacterial and distinct from the genera Simonsiella and Conchiformibius (family Neisseriaceae), with which they share similar morphology and division patterning. Our findings highlight the diversity of novel microbial forms and lifestyles that await characterization using tools complementary to genomics such as microscopy.

Re-estimation of juvenile's Isurus oxyrinchus growth in the Mexican Pacific through a multi-model inference approach and verification of growth band periodicity.

An update of the age and growth for juveniles of shortfin mako shark (Isurus oxyrinchus) from the Mexican Pacific is presented, based on the analysis of growth band counts from dorsal vertebrae of 198 individuals (110 females 74-231 cm of total length, TL, and 88 males 72-231 cm TL) caught during 2008-2018. New available information on vertebral growth band periodicity (biannual deposition in juveniles) and the convenience of using vertebrae form the dorsal region over cervical region to count growth bands, as well as a multi-model approach, were used. The von Bertalanffy growth model (VB), Gompertz, logistic and the two parameters of VB were fitted to the length-at-age. Only the ages ≤ 6 years were used for the fitting of the models and their performance was compared with the small-sample bias-corrected form of Akaike information criterion (AICc), their differences and weights . Following a multi-model inference approach, the model averaged asymptotic length , length-at-age 0 and their unconditional standard error , were estimated for each sex scenario using the 3-parameters version of each model.The precision of growth band counts was acceptable for the different methods used and by two different readers. The Centrum edge analysis (CEA) and marginal increment analysis (MIA) did not support the hypothesis of biannual band pair formation for juveniles, likewise for adults the periodicity could not be verified due to the low sample of large animals. Still, age was estimated assuming the formation of two pairs of growth bands per year during the first five years of age and one pair of bands per year afterwards considering direct validation information. The estimated ages ranged from 0-14 for females and 0-6 for males. The Kimura's likelihood ratio test showed no differences in the growth curves of juveniles by sex (P>0.05). According to the AICc, the 2-VB better fitted the length-at-age data for sex combined (Linf = 386.4 cm, k = 0.12 yr-1 , L0 = 70 cm). The model averaged and were 378.3 cm ( = 64.5) and 69.5 cm = 6.3) respectively. The growth parameters determined for juveniles of I. oxyrinchus are similar with those estimated in other regions, showing relatively fast growth rate as previously reported, medium longevity in comparison to other shark species and natural mortality close to those reported in the last stock assessment for the North Pacific Ocean. These life-history parameters should be considered to evaluate the population in the region to develop better fishery management and conservation measures.

Multiple surface states, nontrivial band topology, and antiferromagnetism in GdAuAl4Ge2

Magnetic topological states of matter provide a fertile playground for emerging topological physics and phenomena. The current main focus is on materials whose magnetism stems from 3d magnetic transition elements, e.g., MnBi2Te4, Fe3Sn2, and Co3Sn2S2. In contrast, topological materials with the magnetism from rare earth elements remain largely unexplored. Here we report rare earth antiferromagnet GdAuAl4Ge2 as a candidate magnetic topological metal. Angle resolved photoemission spectroscopy (ARPES) and first-principles calculations have revealed multiple bulk bands crossing the Fermi level and pairs of low energy surface states. According to the parity and Wannier charge center analyses, these bulk bands possess nontrivial Z 2 topology, establishing a strong topological insulator state in the nonmagnetic phase. Furthermore, the surface band pairs exhibit strong termination dependence which provides insight into their origin. Our results suggest GdAuAl4Ge2 as a rare earth platform to explore the interplay between band topology, magnetism and f electron correlation, calling for further study targeting on its magnetic structure, magnetic topology state, transport behavior, and microscopic properties.

LANDSAT 8 LST Pan sharpening using novel principal component based downscaling model

The panchromatic (PAN) band is accessible at a much higher spatial resolution than the thermal infrared (TIR) band in remote sensing satellites. To mitigate this issue, current research proposes a fusion method based on principal components of PAN and TIR band pairs to enhance the spatial resolution of Land surface temperature (LST) images. In this research, LANDSAT-8 LST images of 100 m resolution have been downscaled to 15 m resolution by the Novel principal component (NPC) based downscaling model. The downscaled LST image's thermal values have been cross-verified by in situ thermal points collected by the thermal data logger and image quality indices. The results have shown the root mean square error (RMSE) of 0.51–0.92 for downscaled LST image from 100m to 15m resolution. The correlation between downscaled LST and ground truth points is between 0.54 and 0.83. The proposed NPC-based LST-PAN combination technique collects spatial details of the Earth's surface from PAN data as well as indulges thermal information of TIR image. The proposed fusion technique has upgraded the spatial goal and peculiarity of TIR images data set. The higher spatial resolution of thermal images can increase the level of precision in various remote sensing applications. These improved data sets can be used in a variety of applications, including urban heat island mapping, agricultural crop monitoring, forest fire detection, and hydrological modeling, to name a few. The increased spatial resolution provided by NPC fusion results in more accurate and consistent temperature readings, leading to improved decision-making and management in these and other applications.

Age and Growth of the Threatened Smalleye Round Ray, Urotrygon microphthalmum, Delsman, 1941, from Northeastern Brazil

The age and growth of Urotrygon microphthalmum were studied using specimens captured between March 2010 and March 2012 as by-catch in the shrimp trawl fishery off the coast of the state of Pernambuco, Brazil. A total of 347 vertebrae were read, 161 from males (81.6–249.55 mm) and 186 from females (86.15–298.1 mm). The estimated average percentage index (IAPE) ranged from 0.71% to 4.33% (mean = 2.5%) in vertebrae from specimens with 1 and 6 band pairs, respectively. In the present study, the different approaches to validation produced variable results (partially valid growth zones). We then decided to discuss the growth of the species considering the formation of an annual ring. There were statistically significant differences in growth between the sexes. The best model to describe male growth was the von Bertalanffy growth model for two phases (VBGM TP) with growth parameters L∞ (maximum theoretical length) = 230.35 mm, k (growth constant) = 1.00, t0 (theoretical age of size zero) = −0.76 years and for females it was the von Bertalanffy with birth size (VBGM L0) model with parameters L∞ = 282.55 mm, k = 0.37. The age of maturity for males and females was 1.52 and 2.02 years, respectively, and the maximum age observed was 5.5 and 8.5 years, respectively. Despite being a fast-growing species, Urotrygon microphthalmum is threatened, probably due to the high mortality levels from shrimp trawling in a very narrow range of the shelf where all the life stages are captured.

Magnetohydrodynamic Instabilities of Double Magnetic Bands in a Shallow-water Tachocline Model. I. Cross-equatorial Interactions of Bands

Along with a butterfly diagram of sunspots, combined observational studies of ephemeral active regions, X-ray and EUV bright points, plage, filaments, faculae, and prominences demonstrate a pattern, which is known as the Extended Solar Cycle. This pattern indicates that the wings of the sunspot butterfly could be extended to much higher latitudes (up to ∼60°), to an earlier time than the start of a sunspot cycle, hence yielding a strong overlap between cycles. Thus, during the ongoing cycle’s activity near 30° latitude in each hemisphere, the next cycle kicks off at around 60°. By representing these epochs of overlaps by oppositely directed double magnetic bands in each hemisphere, we compute the unstable eigenmodes for MHD Rossby waves at the base of the convection zone and study how the properties of these energetically active Rossby waves change as these band pairs migrate equatorward. We find that in each hemisphere the low-latitude band interacts with the high-latitude band and drives the MHD instability as the solar activity progresses from 35°–15° latitude, which is essentially the rising phase. When the activity proceeds further equatorward from 15°, the interaction between low- and high-latitude bands weakens, and the cross-equatorial interaction between two low-latitude bands in each hemisphere starts. The eigenmodes in the latitude-longitude plane also reflect such changes in their pattern as the bend of the active cycle moves below 15° latitude.

Monolayer and bilayer PtCl3 : Energetics, magnetism, and band topology

Two-dimensional (2D) magnetic materials hosting nontrivial topological states are interesting for fundamental research as well as practical applications. Recently, the topological state of 2D Weyl half-semimetal (WHS) was proposed, which hosts fully spin polarized Weyl points robust against spin-orbit coupling in a 2D ferromagnetic system, and single-layer ${\mathrm{PtCl}}_{3}$ was predicted as a platform for realizing this state. Here, we perform an extensive search of 2D ${\mathrm{PtCl}}_{3}$ structures, by using the particle swarm optimization technique and density-functional theory calculation. We show that the desired ${\mathrm{PtCl}}_{3}$ phase corresponds to the most stable one at its stoichiometry. The 2D structure also possesses good thermal stability up to 600 K. We suggest ${\mathrm{SnS}}_{2}$ as a substrate for the growth of 2D ${\mathrm{PtCl}}_{3}$, which has excellent lattice matching and preserves the WHS state in ${\mathrm{PtCl}}_{3}$. We find that uniaxial strains along the zigzag direction maintain the WHS state, whereas small strains along the armchair direction drives a topological phase transition from the WHS to a quantum anomalous Hall (QAH) insulator phase. Furthermore, we study bilayer ${\mathrm{PtCl}}_{3}$ and show that the stacking configuration has strong impact on the magnetism and the electronic band structure. Particularly, the $A{A}^{\ensuremath{'}}$ stacked bilayer ${\mathrm{PtCl}}_{3}$ realizes an interesting topological state---the 2D antiferromagnetic mirror Chern insulator, which has a pair of topological gapless edge bands. Our work provides guidance for the experimental realization of 2D ${\mathrm{PtCl}}_{3}$ and will facilitate the study of 2D magnetic topological states, including WHS, QAH insulator, and magnetic mirror Chern insulator states.

First observation of high-spin states in 116In and possible new region of chirality

High-spin states in neutron-rich indium isotope 116In have been observed for the first time by using incomplete fusion of 7Li on a 116Cd target at a beam energy of 42 MeV. A negative-parity band with πg9/2−1⊗νh11/2 configuration and a pair of positive-parity doublet bands with πg9/2−1⊗ν(g7/2/d5/2)h11/22 configurations have been identified. The positive-parity doublet bands are tentatively interpreted as chiral doublet bands, which is supported by the adiabatic and configuration-fixed constrained triaxial relativistic-mean-field and multiparticle plus rotor model calculations. This observation reports a possible new region of chirality in neutron-rich A≈ 120 mass region.

Cross-Serological Reaction of Glandless Cottonseed Proteins to Peanut and Tree Nut Allergic IgE

Food allergy is a potentially life-threatening health concern caused by immunoglobulin E (IgE) antibodies that mistakenly recognize normally harmless food proteins as threats. Peanuts and tree nuts contain several seed storage proteins that commonly act as allergens. Glandless cottonseed, lacking the toxic compound gossypol, is a new food source. However, the seed storage proteins in cottonseed may act as allergens. To assess this risk, glandless cottonseed protein extracts were evaluated for IgE binding by peanut and tree nut allergic volunteers. ELISA demonstrated that 25% of 32 samples had significant binding to cottonseed extracts. Immunoblot analysis with pooled sera indicated that IgE recognized a pair of bands migrating at approximately 50 kDa. Excision of these bands and subsequent mass-spectrometric analysis demonstrated peptide matches to cotton C72 and GC72 vicilin and legumin A and B proteins. Further, in silico analysis indicated similarity of the cotton vicilin and legumin proteins to peanut vicilin (Ara h 1) and cashew nut legumin (Ana o 2) IgE-binding epitopes among others. The observations suggest both the cotton vicilin and legumin proteins were recognized by the nut allergic IgE, and they should be considered for future allergen risk assessments evaluating glandless cottonseed protein products.

Nanobelt and nanoplatelet structured molybdenum disulfide thin film as a saturable absorber under nanopulsed green laser excitation

Demonstration of saturable absorption (SA) in MoS2 thin films with varying NLO coefficients as a function of reaction time of hydrothermal method is made using the open aperture Z-scan technique. Under nanosecond pulsed laser excitation (532 ​nm, 9 ns, 10 HZ), saturable absorption occurred involving the overtone of electron - hole pair state and band edge state of MoS2. Further higher ground state cross-section than excited state cross-section favors SA process in MoS2 thin films. The strong saturable absorption behaviors of nanobelt like structured MoS2 film could be attributed to the coexistence of 1T and 2H crystal phases and lower dimension morphology that allows more photons to transit to the higher energy state. Earlier the fabrication of MoS2 thin film on a FTO substrate with a varying reaction time of the hydrothermal technique such as 24, 36, 48 and 60 ​h was made. Raman spectrum has two sets of characteristics vibration representing the metallic 1T – octahedral coordination Oh phase and the semiconducting 2H – trigonal prismatic D3h phase. XRD and Raman studies confirm the formation of mixed phases of MoS2 with 1T phase dominating over 2H phase in MoS2 thin films. Here the absorbance and band gap of the MoS2 thin film increased with increase in reaction time. The luminescence spectra exhibit prominent peaks at 594 ​nm and 621 ​nm resulting from a direct bandgap transition and they are mostly due to the VBM splitting at the K-point. All the films exhibit maximum absorbance in the UV region (291 ​nm) due to the excitonic features of MoS2 and notable absorbance in the visible region (680 ​nm) due to the overtones of MoS2 ‘s electron-hole pair. SEM images confirm that nanoplatelet and nanobelt structured MoS2 was formed with varying size with respect to reaction time. Furthermore, while the nanoplatelet structure faded, nanobelts were grown for a prolonged reaction time. Thus, MoS2 nanostructure coated thin film would be useful for the design of saturable absorbers for fabricating optical switches and mode locking devices.

Using a multimodel approach to determine the age and growth of an endangered small shark species in the southern Gulf of Mexico

The bonnethead shark (Sphyrna tiburo), recently upgraded to endangered by the IUCN red list, is frequent in artisanal fisheries’ catches of the southern Gulf of Mexico (GOM). The age and growth parameters were determined from 162 vertebral centra collected from bonnethead sharks (28.2–112.1 cm total length; TL) between 2010 and 2019 in the southern GOM. Two readers determined age estimates using two rounds of independent band pair counts (opaque and translucent). The average percent error (APE) and coefficient of variation (CV) were estimated to assess count precision, and a Bowker test of symmetry was performed to determine potential bias between readers’ counts. The edge and marginal increment analyses were conducted to validate the band pair deposition periodicity, and a multimodel approach was used to select the best growth model. The reading precision was good because APE and CV values were 7.9% and 5.6%, respectively, and the Bowker’s symmetry test indicated no systematic differences between readers. The validation analyses did not provide evidence to determine the band pair deposition periodicity; thus, it was assumed that one band pair is deposited yearly. The oldest male and female were five (95.4 cm TL) and eight (112.1 cm TL) years. The Gompertz growth function provided the best statistical fit and best describes the growth of bonnethead sharks. The parameters were L∞=113 cm, k2=0.49/year, L0=39 cm for females, and L∞=83.6 cm, k2=0.79/year, L0=40.2 cm for males. These are the first age and growth parameters estimated for the bonnethead shark in the southern GOM, which is the second most landed shark and needs a population assessment for proper management.

Two-dimensional superconductors with intrinsic p-wave pairing or nontrivial band topology

Over the past fifteen years, tremendous efforts have been devoted to realizing topological superconductivity in realistic materials and systems, predominately propelled by their promising application potentials in fault-tolerant quantum information processing. In this article, we attempt to give an overview on some of the main developments in this field, focusing in particular on two-dimensional crystalline superconductors that possess either intrinsic p-wave pairing or nontrivial band topology. We first classify the three different conceptual schemes to achieve topological superconductor (TSC), enabled by real-space superconducting proximity effect, reciprocal-space superconducting proximity effect, and intrinsic TSC. Whereas the first scheme has so far been most extensively explored, the subtle difference between the other two remains to be fully substantiated. We then move on to candidate intrinsic or p-wave superconductors, including Sr2RuO4,UTe2,Pb3Bi, and graphene-based systems. For TSC systems that rely on proximity effects, the emphases are mainly on the coexistence of superconductivity and nontrivial band topology, as exemplified by transition metal dichalcogenides, cobalt pnictides, and stanene, all in monolayer or few-layer regime. The review completes with discussions on the three dominant tuning schemes of strain, gating, and ferroelectricity in acquiring one or both essential ingredients of the TSC, and optimizations of such tuning capabilities may prove to be decisive in our drive towards braiding of Majorana zero modes and demonstration of topological qubits.