255 research outputs found
Evaluating the seasonal accumulation of Heat units as an agroclimatic indicator on Baby corn (Zea mays L.) under different sowing windows
Temperature determines the plant's growth and development, which decides the onset of different phenophasic stages of the Baby corn. This study aimed to evaluate the phenological behaviour and yield of Baby corn (Zea mays L.) influenced by sowing windows and heat units with the field investigations carried out during winter (January – April) and kharif (June – September) 2022 at Eastern Block Farm of Tamil Nadu Agricultural University, Coimbatore. Growing Degree Days (GDD), Photo Thermal Units (PTU), Helio Thermal Units (HTU), Relative Temperature Disparity (RTD), Heat Unit Efficiency (HUE) and seasonal efficiency were calculated at different phenological stages. The results revealed that early attainment of phenophases was noticed during winter (62.5 days - January 21st to 27th April) than kharif (77.1 days – 15th June to 4th October). Among seasons, higher accumulation of GDD (1553) and PTU (19099) was observed during kharif 2022, whereas maximum accumulation of HTU (9923) and RTD (2146) was observed in winter 2022. Seasonal efficiency was higher during kharif (118) than during the winter season (81). The sowing windows significantly influenced the higher accumulation of heat units and yield attributes. Hence, higher yield (11922.7 kg ha-1) and HUE (7.3) were obtained during kharif than in winter 2022 (yield – 7849 kg ha-1 and HUE – 5.8). Weather parameters showed a negative correlation except RH-I, WS, SR and HUE during winter 2022 (R2=0.802) and RH-II, WS, RF, Daylength, HUE during kharif 2022, which had a positive correlation (R2=0.795). Baby corn is highly sensitive to increasing temperature. Hence, the study expresses the effect of varying ambient temperature on the duration between the phenological stages and yield.
Studies on the relationship of weather on Fall armyworm damage in maize (Zea mays L.) under different growing environments
Fall armyworm is a recently occurring invasive pest in India, the most important defoliator causing drastic damage to maize production. Hence, the present study aimed to understand the temporal infestation level of Fall armyworms on maize (Zea mays L.) with weather patterns. Field experiments were conducted during Summer (February-May) and Rainy seasons, 2022 (August-December) at Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore. Three different growing environments (GE1, GE2 and GE3) were created by providing staggered sowing. Regression models were developed for per cent leaf damage against three-days lagged (LT3) and seven-day lagged (LT7) weather variables. Results showed that irrespective of growing environments, weather variables showed negative correlation (Tmax: r = -0.57, -0.81*, -0.31; SSH: -0.30, -0.48, -0.39; Tmean: -0.49, -0.23, -0.30; and SR: -0.48, -0.94*, -0.40) during summer season whereas same variables (i.e Tmax =0.62*, 0.41, 0.33; SSH = 0.09, 0.68*, 0.24; Tmean = 0.29, 0.32, 0.44; and SR=0.13, 0 .67*, 0.26 ) showed a positive correlation with PLD. Rainfall exhibits positive relation (0.06, 0.54, 0.53) and negative correlation (-0.64*, -0.10, -0.02) during summer and rainy season, respectively. Among the regression models, LT7 model had higher R2 (0.65 and 0.76) than LT3 (0.57 and 0.68) during summer and rainy seasons, respectively. These models had good regression values of 0.56 and 0.70 during Rainy and Summer, respectively. It was concluded that Tmax (32.9 °C), Tmin (23.7 °C), Tmean (28.3 °C), RH-I (85.6%), RH-II (56.4%), SSH (4.1), SR (274.6 cal cm-2 m-2), afternoon cloud cover (4.8 okta) and weekly total rainfall (10.2 mm) were very conducive for the greater leaf damage
Growth and yield response of winter blackgram (Vigna mungo) under high temperature and elevated CO2 conditions
Blackgram is the most important legume crop grown throughout India. It is mostly cultivated during the rainy and winter seasons in central and southern India. An investigation was carried out during winter 2021 to evaluate the effect of High Day Temperature (ambient+3oC) and Elevated CO2 (600ppm) (HDT and eCO2) and High Day and Night Temperature (ambient+3oC) and Elevated CO2 (600ppm) (HDNT and eCO2) on growth and yield of blackgram (Vigna mungo) under soil plant atmospheric research (SPAR) and ambient conditions with eleven treatments (T1 to T11). The results revealed that significant (P=0.05) increase in photosynthetic rate, stomatal conductance, transpiration rate, number of pods per plant and grain yield by 22.3%, 80.6%, 29.2%, 28% and 41.3%, respectively, under HDT and eCO2 conditions from 46 to 60 DAS (days after sowing) in comparison with HDNT and eCO2 and ambient conditions. The increase in chlorophyll index under HDT and eCO2 during 16 to 30 DAS by 12.9%. The significant increase in the number of flowers per plant and biomass of the blackgram was increased under HDT and eCO2 during 31 to 45 DAS by 7% and 38.1%, respectively. However, the plant height and leaf area index of the blackgram were found to have significantly increased under HDT and eCO2 during the early stage (1 to 15 DAS) by 29.3% and 44.5%, respectively. This experiment indicated a significant increase in crop growth, leaf photosynthesis and yield of blackgram under HDT and eCO2 at flowering stage to pod development stage (31 to 60 DAS) followed by HDNT and eCO2 and ambient condition. The overall findings of the study showed that increased temperature and CO2 levels would result in greater biomass production and increased yield for the black gram.
Categorical, low-dimensional decomposition of human odor space with non-negative matrix factorization
Recent studies using Principal Components Analysis (PCA) support low-dimensional models of odor space, in which one or two dimensions - with hedonic valence featuring prominently - explain most odor variability. Here we use non-negative matrix factorization (NMF) - a nonlinear optimization method - to discover an alternative, reduced-dimensional representation of the Dravnieks odor database (144 odors x 146 descriptors). NMF is theoretically well-suited for these types of analyses, as odor profiling data is inherently non-negative (e.g. descriptors either apply, or do not). We divided the dataset into training and testing halves, and found that RMSD testing error attained a minimum for subspace choice of 25, motivating this as an upper bound for odor perceptual space dimensionality. More parsimonious representations were found by comparing reconstruction errors (fraction of unexplained variance) of NMF with reconstruction errors of PCA on scrambled data (PCAsd). For subspace sizes > 10, NMF error was indistinguishable from PCAsd error, indicating no gain in retaining more than 10 perceptual dimensions. As is typical of NMF basis sets, the 10 odor dimensions we obtain are sparse (only a small subset of the 146 descriptors apply), and categorical (represent a positive valued quality). Moreover, these 10 dimensions were near-orthogonal, with a mean angle of 73 degrees between all pairs of basis vectors. Investigating the distribution of odors in this 10-dimensional space, we find marked clustering (Figure 1), with each odor being well-defined by its membership in a single dimension, and to the exclusion of others. In ongoing work, we are using graph-kernel methods to define a rudimentary mapping between physicochemical features of odorants and the 10 descriptor dimensions
Translocation-coupled DNA cleavage by the Type ISP restriction-modification enzymes
Endonucleolytic double-strand DNA break production requires separate strand cleavage events. Although catalytic mechanisms for simple dimeric endonucleases are available, there are many complex nuclease machines which are poorly understood in comparison. Here we studied the single polypeptide Type ISP restriction-modification (RM) enzymes, which cleave random DNA between distant target sites when two enzymes collide following convergent ATP-driven translocation. We report the 2.7 Angstroms resolution X-ray crystal structure of a Type ISP enzyme-DNA complex, revealing that both the helicase-like ATPase and nuclease are unexpectedly located upstream of the direction of translocation, inconsistent with simple nuclease domain-dimerization. Using single-molecule and biochemical techniques, we demonstrate that each ATPase remodels its DNA-protein complex and translocates along DNA without looping it, leading to a collision complex where the nuclease domains are distal. Sequencing of single cleavage events suggests a previously undescribed endonuclease model, where multiple, stochastic strand nicking events combine to produce DNA scission
2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial fibrillation: executive summary.
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Coupling changes in cell shape to chromosome segregation
Animal cells undergo dramatic changes in shape, mechanics and polarity as they progress through the different stages of cell division. These changes begin at mitotic entry, with cell–substrate adhesion remodelling, assembly of a cortical actomyosin network and osmotic swelling, which together enable cells to adopt a near spherical form even when growing in a crowded tissue environment. These shape changes, which probably aid spindle assembly and positioning, are then reversed at mitotic exit to restore the interphase cell morphology. Here, we discuss the dynamics, regulation and function of these processes, and how cell shape changes and sister chromatid segregation are coupled to ensure that the daughter cells generated through division receive their fair inheritance
Selective Reduction of Post-Selection CD8 Thymocyte Proliferation in IL-15Rα Deficient Mice
Peripheral CD8+ T cells are defective in both IL-15 and IL-15Rα knock-out (KO) mice; however, whether IL-15/IL-15Rα deficiency has a similar effect on CD8 single-positive (SP) thymocytes remains unclear. In this study, we investigated whether the absence of IL-15 transpresentation in IL-15Rα KO mice results in a defect in thymic CD8 single positive (SP) TCRhi thymocytes. Comparison of CD8SP TCRhi thymocytes from IL-15Rα KO mice with their wild type (WT) counterparts by flow cytometry showed a significant reduction in the percentage of CD69− CD8SP TCRhi thymocytes, which represent thymic premigrants. In addition, analysis of in vivo 5-bromo-2-deoxyuridine (BrdU) incorporation demonstrated that premigrant expansion of CD8SP TCRhi thymocytes was reduced in IL-15Rα KO mice. The presence of IL-15 transpresentation-dependent expansion in CD8SP TCRhi thymocytes was assessed by culturing total thymocytes in IL-15Rα-Fc fusion protein-pre-bound plates that were pre-incubated with IL-15 to mimic IL-15 transpresentation in vitro. The results demonstrated that CD8SP thymocytes selectively outgrew other thymic subsets. The contribution of the newly divided CD8SP thymocytes to the peripheral CD8+ T cell pool was examined using double labeling with intrathymically injected FITC and intravenously injected BrdU. A marked decrease in FITC+ BrdU+ CD8+ T cells was observed in the IL-15Rα KO lymph nodes. Through these experiments, we identified an IL-15 transpresentation-dependent proliferation process selective for the mature CD8SP premigrant subpopulation. Importantly, this process may contribute to the maintenance of the normal peripheral CD8+ T cell pool
Winding up superfluid in a torus via Bose Einstein condensation
Phase transitions are usually treated as equilibrium phenomena, which yields telltale universality classes with scaling behavior of relaxation time and healing length. However, in second-order phase transitions relaxation time diverges near the critical point (“critical slowing down”). Therefore, every such transition traversed at a finite rate is a non-equilibrium process. Kibble-Zurek mechanism (KZM) captures this basic physics, predicting sizes of domains – fragments of broken symmetry – and the density of topological defects, long-lived relics of symmetry breaking that can survive long after the transition. To test KZM we simulate Bose-Einstein condensation in a ring using stochastic Gross-Pitaevskii equation and show that BEC formation can spontaneously generate quantized circulation of the newborn condensate. The magnitude of the resulting winding numbers and the time-lag of BEC density growth – both experimentally measurable – follow scalings predicted by KZM. Our results may also facilitate measuring the dynamical critical exponent for the BEC transition
STAT1-dependent expression of energy metabolic pathways links tumour growth and radioresistance to the Warburg effect
<p>Abstract</p> <p>Background</p> <p>The Signal Transducer and Activator of Transcription 1 (STAT1) has traditionally been regarded as a transmitter of interferon signaling and a pro-apoptotic tumour suppressor. Recent data have identified new functions of STAT1 associated with tumourigenesis and resistance to genotoxic stress, including ionizing radiation (IR) and chemotherapy. To investigate the mechanisms contributing to the tumourigenic functions of STAT1, we performed a combined transcriptomic-proteomic expressional analysis and found that STAT1 is associated with regulation of energy metabolism with potential implication in the Warburg effect.</p> <p>Methods</p> <p>We generated a stable knockdown of STAT1 in the SCC61 human squamous cell carcinoma cell line, established tumour xenografts in athymic mice, and compared transcriptomic and proteomic profiles of STAT1 wild-type (WT) and knockdown (KD) untreated or irradiated (IR) tumours. Transcriptional profiling was based on Affymetrix Human GeneChip<sup>® </sup>Gene 1.0 ST microarrays. Proteomes were determined from the tandem mass spectrometry (MS/MS) data by searching against the human subset of the UniProt database. Data were analysed using Significance Analysis of Microarrays for ribonucleic acid and Visualize software for proteins. Functional analysis was performed with Ingenuity Pathway Analysis with statistical significance measured by Fisher's exact test.</p> <p>Results</p> <p>Knockdown of STAT1 led to significant growth suppression in untreated tumours and radio sensitization of irradiated tumours. These changes were accompanied by alterations in the expression of genes and proteins of glycolysis/gluconeogenesis (GG), the citrate cycle (CC) and oxidative phosphorylation (OP). Of these pathways, GG had the most concordant changes in gene and protein expression and demonstrated a STAT1-dependent expression of genes and proteins consistent with tumour-specific glycolysis. In addition, IR drastically suppressed the GG pathway in STAT1 KD tumours without significant change in STAT1 WT tumours.</p> <p>Conclusion</p> <p>Our results identify a previously uncharacterized function of STAT1 in tumours: expressional regulation of genes encoding proteins involved in glycolysis, the citrate cycle and mitochondrial oxidative phosphorylation, with predominant regulation of glycolytic genes. STAT1-dependent expressional regulation of glycolysis suggests a potential role for STAT1 as a transcriptional modulator of genes responsible for the Warburg effect.</p
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