Analysis Of Variability Research Articles

Cryo-EM and Molecular Dynamics Simulations Reveal Hidden Conformational Dynamics Controlling Ammonia Transport in Human Asparagine Synthetase.

How motions in enzymes might be linked to catalytic function is of considerable general interest. Recent advances in X-ray crystallography and cryogenic electron microscopy offer the promise of elucidating functionally relevant motions in proteins that are not easily amenable to study by other biophysical methods. Here we use 3D variability analysis (3DVA) on cryo-EM maps for wild type (WT) human asparagine synthetase (ASNS) and the R142I ASNS variant to identify conformational changes in the Arg-142 side chain, which mediates the formation of a catalytically relevant intramolecular tunnel. Our 3DVA results for WT ASNS are consistent with independent molecular dynamics (MD) simulations on a model generated from the X-ray structure of human ASNS. Moreover, MD simulations of computational models for the ASNS/β-aspartyl-AMP/MgPPi and R142I/β-aspartyl-AMP/MgPPi ternary complexes, suggest that the structural integrity of the tunnel is impaired in the R142I variant when β-aspartyl-AMP is present in the synthetase active site. The kinetic properties of the R142I ASNS variant support the proposed function of Arg-142. These studies illustrate the power of cryo-EM to identify localized motions and dissect the conformational landscape of large proteins. When combined with MD simulations, 3DVA is a powerful approach to understanding how conformational dynamics might regulate function in multi-domain enzymes possessing multiple active sites.

Analysis of Genome Variability of Escherichia coli when Exposed to Ionizing Radiation

The study of changes in the genetic apparatus of biological systems due to the influence of physical factors contributes to understanding the mechanisms of adaptation. The article is devoted to the analysis of the genome of the modified Escherichia coli PL-6 variant obtained as a result of repeated and gradually increasing exposure to 60Co ɤ-rays at the Researcher facility. The integrity of the genetic material of the studied bacterial cells was checked by electrophoresis in 1.7% agarose gel. For the analysis of genome modifications, primers were designed to amplify several loci characterized by homology in a variety of E. coli strains. Based on the indicators of the number and size of amplified products using each of the presented primer combinations in E. coli before and after gamma irradiation, a significant change in the genome was established.

Comparative evaluation of the promising lines of winter soft wheat in the south of the Rostov region

The analysis of variability of winter soft wheat lines by quantitative traits is presented. The research was conducted in 2020–2023 in the Rostov region. Seven lines of winter soft wheat of the competitive variety trial were taken as an object of research. The Ermak variety was used as a standard. The yields of the lines during the years of study averaged from 9.78 to 10.12 t/ha with an average of 9.76 t/ha in the experiment. Plant height ranged from 85.0 to 115.0 cm. All the lines studied were classified as small- to medium-grained (32.9–45.9 g) in terms of 1000 grain weight. On average for the years of study, the minimum mass of 1000 grains was formed by the line 1638/19 (34.6 g), and the maximum – by the line 1361/19 (43.5 g). The lines had different groups of ripeness according to the indicator of the earing date. The spikelet length varied from 7.3 to 10.0 cm. The highest spikelet length was formed by the line 1361/19 (10.0 cm), the shortest – by the line 1120/19 (7.3 cm). The number of productive stems ranged from 471 to 924 stems/m2. The maximum number of productive stems for the years of the study was formed by the line 1921/20 (758 pcs./m2), the minimum – by the line 1361/19 (689 pcs./m2). The number of grains per plant ranged from 61.6 to 110.6. On average, the highest number of grains per plant was formed by the line 1638/19 (100.6 pcs.), the lowest – 1343/19 (70.4 pcs.). The grain weight per plant averaged 3.54 g and ranged from 2.26 to 4.56 g. The number of grains per ear varied from 28.9 to 51.5 pieces, the maximum number was formed by the lines 1361/19 (42.7 pcs.) and 1638/19 (41.2 pcs.). In terms of the grain weight per ear the standard was exceeded by the line 1361/19 (1.93 g), the values for the indicator varied from 1.02 to 2.28 g.

Feeding Behavior Modifies the Circadian Variation in RR and QT intervals by Distinct Mechanisms in Mice.

Rhythmic feeding behavior is critical for regulating phase and amplitude in the »24-hour variation of heart rate (RR intervals), ventricular repolarization (QT intervals), and core body temperature in mice. We hypothesized changes in cardiac electrophysiology associated with feeding behavior were secondary to changes in core body temperature. Telemetry was used to record electrocardiograms and core body temperature in mice during ad libitum-fed conditions and after inverting normal feeding behavior by restricting food access to the light cycle. Light cycle-restricted feeding modified the phase and amplitude of 24-hour rhythms in RR and QT intervals, and core body temperature to realign with the new feeding time. Changes in core body temperature alone could not account for changes in phase and amplitude in the »24-hour variation of the RR intervals. Heart rate variability analysis and inhibiting β-adrenergic and muscarinic receptors suggested that changes in the phase and amplitude of 24-hour rhythms in RR intervals were secondary to changes in autonomic signaling. In contrast, changes in QT intervals closely mirrored changes in core body temperature. Studies at thermoneutrality confirmed that the daily variation in QT interval, but not RR interval, primarily reflected daily changes in core body temperature (even in ad libitum-fed conditions). Correcting the QT interval for differences in core body temperature helped unmask QT interval prolongation after starting light cycle-restricted feeding and in a mouse model of long QT syndrome. We conclude feeding behavior alters autonomic signaling and core body temperature to regulate phase and amplitude in RR and QT intervals, respectively.

Analysis of Heart Rate Variability in Newborns Dogs with Different Types of Delivery during the First 35 Days of Life.

The present study aimed to evaluate the influence of the autonomic nervous system on cardiovascular function during the first 35 days of life in different types of delivery, using heart rate variability (HRV) indices. Thirty newborns were equally divided into two groups based on delivery type: eutocic delivery (EG) and emergency cesarean section (CG). Electrocardiographic evaluation was performed at birth (T0), 24 h postpartum (T1), and at 7, 14, 21, 28, and 35 days of life (T2 to T6). Physical parameters, neonatal reflexes, and Apgar scores were recorded. Over 35 days, the values of the time domain indices were higher in the GE group and increased with age. In the frequency domain, the low frequency (LF) index was higher in the CG, and the opposite occurred for the high frequency (HF) index. Since the CG presented lower HRV than the EG, it was shown that the type of delivery should be considered for the assessment of autonomic nervous system activity in neonates. Thus, as predictive factors of vitality, HRV and Apgar scores can help in the face of neonatal depression, demonstrating that delivery by emergency cesarean section can predispose newborns to delays in the autonomic influence on the heart.

Long term follow-up of heart rate variability in healthcare workers with mild COVID-19.

Prior investigations into post-COVID dysautonomia often lacked control groups or compared affected individuals solely to healthy volunteers. In addition, no data on the follow-up of patients with SARS-CoV-2-related autonomic imbalance are available. In this study, we conducted a comprehensive clinical and functional follow-up on healthcare workers (HCWs) with former mild COVID-19 (group 1, n = 67), to delineate the trajectory of post-acute autonomic imbalance, we previously detected in a case-control study. Additionally, we assessed HCWs for which a test before SARS-CoV-2 infection was available (group 2, n = 29), who later contracted SARS-CoV-2, aiming to validate findings from our prior case-control investigation. We evaluated autonomic nervous system heart modulation by means of time and frequency domain heart rate variability analysis (HRV) in HCWs during health surveillance visits. Short-term electrocardiogram (ECG) recordings, were obtained at about 6, 13 months and both at 6 and 13 months from the negative SARS-CoV-2 naso-pharyngeal swab (NPS) for group 1 and at about 1-month from the negative NPS for group 2. HCWs who used drugs, had comorbidities that affected HRV, or were hospitalized with severe COVID-19 were excluded. Group 1 was split into three subgroups clinically and functionally followed at, about 6 months (subgroup-A, n = 17), 13 months (subgroup-B, n = 37) and both at 6 and 13 months (subgroup-C, n = 13) from the negative SARS-CoV-2 NPS. In subgroup-A, at 6-month follow-up compared with baseline, the spectral components in the frequency domain HRV parameters, showed an increase in normalized high frequency power (nHF) (t = 2.99, p = 0.009), a decrease in the normalized low frequency power (nLF) (t = 2.98, p = 0.009) and in the LF/HF ratio (t = 3.13, p = 0.006). In subgroup B, the comparison of the spectral components in the frequency domain HRV parameters, at 13-month follow-up compared with baseline, showed an increase in nHF (t = 2.54, p = 0.02); a decrease in nLF (t = 2.62, p = 0.01) and in the LF/HF ratio (t = 4.00, p = 0.0003). In subgroup-C, at both 6 and 13-month follow-ups, the spectral components in the frequency domain HRV parameters were higher than baseline in nHF (t = 2.64, p = 0.02 and (t = 2.13, p = 0.05, respectively); lower in nLF (t = 2.64, p = 0.02 and (t = 2.13, p = 0.05, respectively), and in LF/HF (t = 1.92, p = 0.08 and (t = 2.43, p = 0.03, respectively). A significant proportion of HCWs reported persistent COVID-19 symptoms at both the 6 and 13-month follow-ups, seemingly unrelated to cardiac autonomic balance. In group 2 HCWs, at 1-month follow-up compared with baseline, the spectral components in the frequency domain HRV parameters, showed a decrease in nHF (t = 2.19, p = 0.04); an increase in nLF (t = 2.15, p = 0.04) and in LF/HF (t = 3.49, p = 0.002). These results are consistent with epidemiological data suggesting a higher risk of acute cardiovascular complications during the first 30 days after COVID-19. The SARS-CoV-2 associated autonomic imbalance in the post-acute phase after recovery of mild COVID-19 resolved 6 months after the first negative SARS-CoV-2 NPS. However, a significant proportion of HCWs reported long-term COVID-19 symptoms, which dot not seems to be related to cardiac autonomic balance. Future research should certainly further test whether autonomic imbalance has a role in the mechanisms of long-COVID syndrome.

Simulation of climate-adaptation responses to rainfall variability on rainfed yield anomalies

Climate adaptation offers promising approaches to cope with the detrimental impacts of climate change on rainfed agriculture, intending to mitigate yield losses and safeguard food security worldwide. This is especially critical in the semi-arid tropics, characterized by highly variable and often intensified rainfall regimes. The current study explored the potential contribution of climate adaptation measures, specifically sowing windows and supplemental irrigation (SI), to offset the impacts of rainfall variability on rainfed crop yield in the Thondamuthur block, India. Under the proposed adaptation measures, this study analyzed the relationship between historical rainfall variability (1951–2019) and rice, maize, and sorghum yield anomalies. A seamlessly integrated framework was developed to link rainfall variability analysis with yield response simulations using the AquaCrop model. Rainfall classification analysis indicated an increase in rainfall availability during the Kharif season and a decrease during the Rabi season in Period III compared with the baseline. The late-sown Kharif and early-sown Rabi crops demonstrated effective climate adaptation, with the 27th and 38th SMWs identified as optimal climate-adapted sowing weeks, respectively. Significant decreases of 10% and 12% in SI requirements were observed in early-sown Rabi maize and sorghum, respectively. The results showed that substituting Rabi rice and maize with Rabi sorghum led to reductions of 90% and 75% in seasonal SI requirements, respectively. The early-sown Rabi rice and maize contributed to 88% and 12% relative yield increases, respectively, compared with the normal-sown. This study highlights the effectiveness of climate adaptation measures in enabling farmers to withstand climate-induced anomalies.

Spectral analysis of heart rate variability in patients with newly diagnosed atrial fibrillation

Spectral analysis of heart rate variability gives an idea of the role of the autonomic nervous system in the regulation of chronotropic heart function and can be used to evaluate the effectiveness of drug therapy. The selection of drug therapy taking into account the individual clinical form of atrial fibrillation, as well as the vegetative status of the patient, will undoubtedly increase the effectiveness of treatment. In this study, spectral parameters were studied in patients with newly diagnosed atrial fibrillation and the effect of the antiarrhythmic drug class III miodarone on these parameters.

Past and future climate variability analysis in bhutan

Past and future climate variability analysis in bhutan

Genetic variability, correlation and path analysis in the BC2F2 population of groundnut

The present study was carried out in the backcross population of groundnut involving TMV 7 and ICG 15419. Allele-specific primers were used to screen the population for high oleic acid and a total of 11 yield-contributing traits were included in this study. The number of primary and secondary branches had higher estimates of PCV and GCV whereas pod yield per plant had moderate PCV but low GCV. Along with the variability parameters, plant height, number of primary and secondary branches, pod width, 100 pod weight, oleic acid content and linoleic acid content had good estimates of heritability and genetic advance as a percent of the mean, whereas pod yield per plant had moderate and low, heritability and GAM respectively, with a negatively significant skewed distribution. Association analysis exhibited a positive correlation between the number of primary branches, number of secondary branches, pod length and 100 pod weight with pod yield per plant and it was evident that oleic acid was indirectly proportional to linoleic acid content. Hundred pod weights had the highest direct effect on pod yield per plant. Selection based on traits with a better relationship with pod yield per plant and moderate to high estimates of PCV, GCV, heritability and genetic advancement would help in accelerating the groundnut improvement program. High oleic, low linolenic lines of BC2F2 with better pod yield would be forwarded to the next generation.

Spatial variability and source analysis of soil heavy metals: A case study of the key planting area of special agricultural products in Cangxi County, China.

Heavy metal pollution in farmland soil represents a considerable risk to ecosystems and human health, constituting a global concern. Focusing on a key area for the cultivation of special agricultural products in Cangxi County, we collected 228 surface soil samples. We analyzed the concentration, spatial distribution, and pollution levels of six heavy metals (Cr, Cu, Pb, Ni, Zn, and Hg) in the soil. Moreover, we investigated the sources and contribution rates of these heavy metals using Principal Component Analysis/Absolute Principal Component Scores (PCA/APCS) and Positive Matrix Factorization (PMF) models. Our findings indicate that none of the six metals exceeded the pollution thresholds for farmland soils. However, the mean concentrations of Cr and Ni surpassed the background levels of Sichuan Province. A moderate spatial correlation existed between Pb and Ni, attributable to both natural and anthropogenic factors, whereas Zn, Cu, Hg, and Cr displayed a strong spatial correlation, mainly due to natural factors. The spatial patterns of Cr, Cu, Zn, Pb, and Ni were similar, with higher concentrations in the northern and eastern regions and lower concentrations centrally. Hg's spatial distribution differed, exhibiting a broader range of lower values. The single pollution index evaluation showed that Cr and Ni were low pollution, and the other elements were no pollution. The average value of comprehensive pollution index is 0.994, and the degree of pollution is close to light pollution. Predominantly, higher pollution levels in the northern and eastern regions, lower around reservoirs. The PCA/APCS model identified two main pollution sources: agricultural traffic mixed source (65.2%) and natural parent source (17.2%). The PMF model delineated three sources: agricultural activities (32.59%), transportation (30.64%), and natural parent sources (36.77%). Comparatively, the PMF model proved more accurate and reliable, yielding findings more aligned with the study area's actual conditions.

Effect of listening music (Rabindra Sangeet) on autonomic dysfunction in patients with generalized anxiety disorder: A power spectral analysis of heart rate variability

Background: Power spectral analysis of heart rate variability (HRV) is a complex method for assessing cardiac autonomic nerve function (CANF) in generalized anxiety disorder (GAD) patients which is a common mental disorder in the world. Recently, music therapy is used as an adjunct to pharmacotherapy in clinical psychiatry for GAD. Objective: To observe the effect of music therapy on CANF by power spectral analysis of HRV in GAD patients was designed. Methods: This prospective non randomized intervention study was done in 2019 on 60 newly diagnosed GAD patients aged 20- 40 years, both male and female. Among them 30 patients were under music therapy with listening of Raga Bhairabi based Rabindra sangeet for 3 months and 30 patients were without music therapy for three months. Age, sex and BMI matched healthy control were also enrolled. HRV of all GAD patients and control were recorded at baseline and after three months of follow up. HRV were recorded by Power Lab 8/35. For statistical analysis Bonferroni’s Post Hoc test and paired sample‘t’ test were done. Results: Total power, LF power, HF power, LF n.u, HF n.u and LF/HF and were significantly lower in all GAD patients compared to healthy control at baseline. After 3 months of music therapy, significant increment of Total power, HF power, HF n.u and significant decrement of LF n.u and LF/HF occurred whereas no change of these except HF n.u were noted in patients without music after 3 months. Moreover, after three months of music therapy, Total power, HF n.u, and LF/HF were almost same to control. Conclusion: So this study concluded that music therapy improve autonomic dysfunction in GAD patients and can be used as an adjunct to pharmacotherapy in clinical psychiatry for good cardiac health in GAD patients. J Bangladesh Soc Physiol 2022;17(2): 91-100

Studies on Genetic Variability, Correlation and Path Coefficient Analysis for Yield and Yield Contributing Traits in Bread Wheat (Triticum aestivum L.)

A study was undertaken to analyse the genetic variability, correlation and estimates path coefficient analysis of yield and yield contributing traits in twenty-eight wheat genotypes grown at BAU Agricultural Farm, ranchi during Rabi season of 2019-2020 in three different dates of sowing with an interval of 15 days which is considered as three environments E1, E2, E3. In this investigation the pooled analysis of variance revealed that the treatments were highly significant for all the characters. Wide genetic variation was observed among genotypes for plant height, number of grains per spike, 1000 kernel weight, days to maturity and flag leaf area. Considering genetic parameters, high genotypic co-efficient of variation (GCV), was observed for 1000 kernel weight (11.95), no of grains per spike (12.73), flag leaf area (13.74), spike length (15.83), grain yield per plant (17.64), no of effective tillers (18.38) Whereas, low GCV was observed for plant height (3.49), days to 50% flowering (1.46), days to maturity (2.54) and harvest index (6.90). In most of the cases, phenotypic variances were higher than the genotypic variances. Environmental variance is much higher in harvest index (35.64), days to 50% flowering (33.47). low environmental variance was observed in plant height (16.75), flag leaf area (10.29), days to maturity (13.93), no of grains per spike (14.07), spike length (0.49) and biological yield (35.64). High heritability with low genetic advance in per cent of mean was observed for plant height, days to maturity, days to 50% flowering & harvest index which indicated the involvement of non-additive gene action for the expression of this character and selection for such trait might not be rewarding. High heritability with high genetic advance in per cent of mean was observed for grain yield per plant (27.73), no of grains per spike (20.93), 1000 kernel weight (23.58) and no of effective tillers (27.91) indicating that these traits were under additive gene control and selection for genetic improvement for these traits would be effective. Biological yield had high positive and significant correlation with plant height, number of effective tillers and number of grains per spike. Path coefficient analysis revealed maximum direct contribution towards yield per plot with sheath length followed by grains per spike.

Changes in autonomic regulation in workers under conditions of long-term fluoride intoxication

Introduction. Long-term intake and accumulation of fluoride compounds in the body, in addition to pathological changes in the bronchopulmonary system, bone tissue, liver, leads to changes in the regulatory systems, primarily the autonomic ones, in the conditions of chronic fluoride intoxication. The aim of the study was to assess the nature and severity of the changes in autonomic regulation in workers of the main occupations in aluminum production under exposure to chronic fluoride intoxication. Material and methods. We examined fifty two male workers of aluminum production over the age range from 40 to 56 years; work experience was more than 15 years. Autonomic regulation was assessed using spectral analysis of the heart rate variability, highlighting oscillations in the ranges of very low frequency (0.004–0.08 Hz), low (0.09–0.16 Hz), and high frequencies (0.17–0.5 Hz). Results. Analysis of the heart rate variability made it possible to identify 4 groups of subjects: 16 individuals had a moderate decrease in variability and a predominance of low-frequency oscillations, 12 subjects examined cases had a pronounced decline in variability in all frequency ranges; a decrease in the capabilities of autonomic regulation was manifested during a test with hyperventilation by an increase in very low frequency oscillations frequency indicating the need for activation of suprasegmental autonomic centers. In 24 subjects, the stable predominance of low-frequency oscillations indicates an enhancement in sympathetic influence. In response to the hyperventilation test, most of them (18 subjects were included in the group 3) showed an increase in low and very low frequency oscillations as a sign of a violation of baroreceptor regulation. Limitations. The study was limited by the number of workers with long-term work experience in aluminum production who underwent an in-depth medical examination. Conclusion. Changes in autonomic regulation are observed in the majority of aluminum production workers with long-term work experience, which gives grounds to recommend a study of neurovegetative status using heart rate variability analysis during preventive examinations to identify individuals at high risk of developing comorbid diseases.

How reliable are femoropelvic kinematics during deep squats? The influence of subject-specific skeletal modelling on measurement variability

BackgroundBiplanar radiography displays promising results in the production of subject-specific (S.specific) biomechanical models. However, the focus has predominantly centred on methodological investigations in gait analysis. Exploring the influence of such models on the analysis of high range of motion tasks linked to hip pathologies is warranted. The aim of this study is to investigate the effect of S.Specific modelling techniques on the reliability of deep squats kinematics in comparison to generic modelling. Methods8 able-bodied male participants attended 5 motion capture sessions conducted by 3 observers and performed 5 deep squats in each. Prior to each session a biplanar scan was acquired with the reflective-markers attached. Inverse kinematics of pelvis and thigh segments were calculated based on S.specific and Generic model definition. Agreement between the two models femoropelvic orientation in standing was assessed with Bland-Altman plots and paired t- tests. Inter-trial, inter-session, inter-observer variability and observer/trial difference and ratio were calculated for squat kinematic data derived from the two modelling approaches. ResultsCompared to the Generic model, the S.Specific model produced a calibration trial that is significantly offset into more posterior pelvis tilt (–2.8±2.7), hip extension (–2.2±3.8), hip abduction (–1.2±3.6) and external rotation (–13.8±11.4). The S.specific model produced significantly different squat kinematics in the sagittal plane of the pelvis (entire squat cycle) and hip (between 40 % and 60 % of the squat cycle). Variability analysis indicated that the error magnitude between the two models was comparable (difference<2°). The S.specific model exhibited a lower variability in the observer/trial ratio in the sagittal pelvis and hip, the frontal hip, but showed a higher variability in the transverse hip. SignificanceS.specific modelling appears to introduce a calibration offset that primarily translates into an effect in the sagittal plane kinematics. However, the clinical added value of S.specific modelling in terms of reducing experimental sources of kinematic variability was limited.

Fetal magnetocardiographic recordings with a prototype bed-based array system of optically-pumped magnetometers

ObjectiveTo record and extract features of fetal cardiac activities with a semi-rigid prototype optically-pumped magnetometers (OPM) sensor array. MethodsFetal magnetocardiography (fMCG) data were collected from 15 pregnant women between 28 and 40 weeks gestation. Mothers were lying flat in a customized bed with sensors touching their abdomen from below using a prototype grid. fMCG was extracted to perform standard fetal heart rate variability (FHRV) analysis. ResultsfMCG was observed in 13 of the 15 pregnant women. OPM FHRV indicators were in the range of previous SQUID studies. ConclusionSemi-rigid prototype OPM system has the ability to record quality fMCG. fMCG is capable of identifying lethal cardiac rhythm disturbances in the fetus. Our novel application of OPM technology may lower costs and increase maternal comfort, thus expanding fMCG's generalizability.

BASiCS workflow: a step-by-step analysis of expression variability using single cell RNA sequencing data

Cell-to-cell gene expression variability is an inherent feature of complex biological systems, such as immunity and development. Single-cell RNA sequencing is a powerful tool to quantify this heterogeneity, but it is prone to strong technical noise. In this article, we describe a step-by-step computational workflow that uses the BASiCS Bioconductor package to robustly quantify expression variability within and between known groups of cells (such as experimental conditions or cell types). BASiCS uses an integrated framework for data normalisation, technical noise quantification and downstream analyses, propagating statistical uncertainty across these steps. Within a single seemingly homogeneous cell population, BASiCS can identify highly variable genes that exhibit strong heterogeneity as well as lowly variable genes with stable expression. BASiCS also uses a probabilistic decision rule to identify changes in expression variability between cell populations, whilst avoiding confounding effects related to differences in technical noise or in overall abundance. Using a publicly available dataset, we guide users through a complete pipeline that includes preliminary steps for quality control, as well as data exploration using the scater and scran Bioconductor packages. The workflow is accompanied by a Docker image that ensures the reproducibility of our results.

Re-evaluating soil moisture-based drought criteria for rainfed crops in peninsular India

Background: Peninsular India, being completely under the influence of monsoonal climate, suffers crop yield variability due to rainfall distribution-induced soil moisture constraints. Timely and appropriate assessment of this rainfall and soil moisture-induced crop yield variability serves as a key for exemplary relief assistance. Per cent available soil moisture (PASM) is one among several drought declaration indices followed by stakeholders in India for declaration of drought, needs re-evaluation as the existing criteria in unable to capture the yield loss due to ineffective classification of PASM categories. This study attempts to revise the agricultural drought classes by PASM based on relationships established between yield of major rainfed crops of the study region and PASM.Methods: Analysis of yield variability due to PASM was carried out based on long term observations in experiments conducted at five dry farming locations (Akola, Parbhani, Kovilpatti, Ananthapuramu and Bengaluru) of peninsular India. The average yield for each category of PASM was calculated and tabulated for regression analysis. The PASM versus yield in each group was correlated and regression equations were developed if significant positive correlations were established.Results: The range of available soil moisture to obtain at least 50 percent of optimum yield in cereals (maize: 26 and finger millet: 52.9 PASM), pulses (pigeon pea: 37.2 PASM), oilseeds (soybean: 26.8 to 30.5, groundnut: 53.8 to 61.7 PASM) and commercial crops (cotton: 26.3 PASM) was 26–61 percent.Conclusion: The revised PASM-based drought classes (0–50 severe; 51–75 mild and 76–100 no drought) would help in drought declaration and precise identification of drought-hit areas for meaningful relief assistance. However, there is further investigation is needed to include a soil component for further fine-tuning of the criteria.

Winter “warm Arctic-cold Eurasia” pattern and its statistical linkages to oceanic precursors during the era of satellite observations

AbstractA striking recurrent feature of winter climate variability is the “warm Arctic-cold Eurasia” (WACE) pattern of opposite sign anomalies of surface air temperature (SAT) in the Barents Sea region and midlatitude Eurasia. Its origins and mechanisms are hotly debated, and its predictability remains unknown. This study investigates statistical relationships of the winter WACE dipole with concurrent anomalies of atmospheric circulation and oceanic precursors during the era of satellite observations. The results reveal a high potential for seasonal predictability of not only the WACE dipole but also several related indicators of winter climate variability, including the Arctic and Eurasian SAT anomalies. During subperiods of extreme covariability between the Arctic and Eurasian SATs around the early 1980s and late 2000s, most of the WACE variability is explained by ocean temperature and surface turbulent heat flux anomalies in the Barents Sea region during the preceding months. Anomalies in summer Atlantic water temperature (AWT) and autumnal sea surface temperature (SST) in this region explain about 70–80% of the variance of the following winter WACE variability during all events of strong Arctic-Eurasian SAT covariability. Analysis of SST variability in the Arctic-North Atlantic region suggests that the winter WACE link to the summer AWT anomalies reflects an atmospheric response to a large-scale surface reemergence of ocean temperature anomalies. However, this linkage had been robust only until the early 2000s. Since then, the winter WACE variability has been strongly related to autumnal SST anomalies in the Barents Sea region and the North Pacific.

Efficient Verilog-A based time-domain variability analysis method for passive photonic integrated circuits

The performance of silicon photonic integrated circuits (PICs), especially wavelength filters, can be highly sensitive to variations in the fabrication process due to the large refractive index contrast of the silicon on insulator platform. This paper proposes an easy-to-implement and efficient time-domain variability analysis method for passive PICs. The method utilizes the polynomial chaos expansion technique to construct Verilog-A based models for estimating the statistical information of stochastic passive PICs. In comparison to existing methods, this approach is considerably easy to implement, efficient, and exhibits superior scalability, particularly as the numbers of ports and random parameters in the studied PICs increase. The technique is demonstrated via the time-domain variability analysis of a ring-resonator-based wavelength filter and a Mach-Zehnder interferometer-based demultiplexer filter.