Genetic Variability, Correlation and Path Analysis in Fenugreek Grown under Sub-humid Sub-tropical Red Lateritic Belt of Eastern India

Thirty genotypes of fenugreek were grown during two consecutive winter seasons in sub-humid sub-tropical red lateritic belt of eastern India. Genetic variability, correlation and path coefficients were studied on eight agronomic characters, viz., plant height, days to flowering, branches per plant, pods per plant, pod length, seeds per pod, test weight and seed yield per plant. Analysis of variance pooled over the seasons revealed that the mean squares due to genotypes for all the characters studied were highly significant indicating presence of genetic variation in the test population. The estimates of genotypic and phenotypic coefficient of variation were high for branches per plant, moderate for plant height and test weight, and low for days to flowering and pod length. Heritability estimates were high for plant height, days to flowering, branches per plant and test weight and low for pod number, pod length, seeds per pod and seed yield The results of phenotypic and genotypic coefficient of variability, heritability and genetic advance revealed that improvement through selection for branches per plant, pods per plant and test weight would be effective in this population. Seed yield was positively and significantly correlated with plant height, branch number, pods per plant and seeds per pod at both genotypic and phenotypic levels indicating the importance of these characters for seed yield. The results of path analysis indicated that selection for tall plant height, late flowering with reasonable branch number, high number of seeds per pod and pods per plant are important which will help improve seed yield in this population

Stability analysis for seed yield and its component characters in fenugreek (Trigonella foenum-graecum L.)

Fourteen genotypes of fenugreek (Trigollella foenum-graecum) were grown at Sriniketan (West Bengal) in four different environments during winter season for three consecutive years. Genotype x environment (G x E) interaction was studied for seed yield and its component characters namely, pods plant-', seeds pod" and test weight. G x E interactions were highly significant for all the characters. Both linear and non-linear components of G x E interactions were highly significant, non-linear component being predominant for seeds pod" and seed yield plant·" while linear component was predominant for test weight. However, both linear and non-linear components were equally important for pods plant-'. The genotypes UM-129, UM-301 and UM-302 were stable. &nbsp

Analysis of genetic divergence in fenugreek (Trigonella foenum-graecum L.)

Genetic divergence among 22 genotypes of fenugreek (Trigon ella foenum-graecum) was estimated for 8 quantitative characters using Mahalanobis's D' statistic and the genotypes were grouped into 6 clusters. Cluster I consisted of maximum number of 13 genotypes followed by 4 and 2 genotypes in clusters II and III, respectively. Three clusters were monogenotypic. Clustering pattern of genotypes was not related to geographical differentiation. Inter-cluster distance was highest between clusters III and VI and lowest between clusters II and VI while, intra-cluster distance was highest in cluster III. Plant height, pods plant-1, days to flowering and test weight were the major forces for divergence. &nbsp

Genetic variability, correlation and path analysis in fenugreek (Trigonella foenum-graecum L.)

Genetic variability was studied in a population of 22 genotypes of fenugreek (Trigonella foenum-graecum) at Sriniketan (West Bengal). Phenotypic and genotypic coefficients of variability were high for stem weight; moderate for plant height, branches plant-1, days to flowering, duration of flowering, shelling per cent and test weight; and low for pod length. High to moderate estimates of heritability coupled with moderate to high genetic advance were recorded for plant height, days to flowering, duration of flowering, shelling per cent and test weight indicating the predominance of additive gene action. Grain yield was positively correlated with branches plant-1 pods plant-1, pod length, seeds pod-1, pod weight, biological yield, shelling per cent and harvest index at both phenotypic and genotypic levels. Results of path analysis revealed that days to flowering, pods plant-1, pod length and seeds podol are the important characters determining seed yield in fenugreek. &nbsp

Penetrating particle ANalyzer (PAN)

PAN is a scientific instrument suitable for deep space and interplanetary missions. It can precisely measure and monitor the flux, composition, and direction of highly penetrating particles ($> \sim$100 MeV/nucleon) in deep space, over at least one full solar cycle (~11 years). The science program of PAN is multi- and cross-disciplinary, covering cosmic ray physics, solar physics, space weather and space travel. PAN will fill an observation gap of galactic cosmic rays in the GeV region, and provide precise information of the spectrum, composition and emission time of energetic particle originated from the Sun. The precise measurement and monitoring of the energetic particles is also a unique contribution to space weather studies. PAN will map the flux and composition of penetrating particles, which cannot be shielded effectively, precisely and continuously, providing valuable input for the assessment of the related health risk, and for the development of an adequate mitigation strategy. PAN has the potential to become a standard on-board instrument for deep space human travel. PAN is based on the proven detection principle of a magnetic spectrometer, but with novel layout and detection concept. It will adopt advanced particle detection technologies and industrial processes optimized for deep space application. The device will require limited mass (~20 kg) and power (~20 W) budget. Dipole magnet sectors built from high field permanent magnet Halbach arrays, instrumented in a modular fashion with high resolution silicon strip detectors, allow to reach an energy resolution better than 10\% for nuclei from H to Fe at 1 GeV/n

Power laws in microrheology experiments on living cells: comparative analysis and modelling

We compare and synthesize the results of two microrheological experiments on the cytoskeleton of single cells. In the first one, the creep function J(t) of a cell stretched between two glass plates is measured after applying a constant force step. In the second one, a micrometric bead specifically bound to transmembrane receptors is driven by an oscillating optical trap, and the viscoelastic coefficient $G_e(\omega)$ is retrieved. Both $J(t)$ and $G_e(\omega)$ exhibit power law behavior: $J(t)= A(t/t_0)^\alpha$ and $\bar G_e(\omega)\bar = G_0 (\omega/\omega_0)^\alpha$, with the same exponent $\alpha\approx 0.2$. This power law behavior is very robust ; $\alpha$ is distributed over a narrow range, and shows almost no dependance on the cell type, on the nature of the protein complex which transmits the mechanical stress, nor on the typical length scale of the experiment. On the contrary, the prefactors $A_0$ and $G_0$appear very sensitive to these parameters. Whereas the exponents $\alpha$ are normally distributed over the cell population, the prefactors $A_0$ and $G_0$ follow a log-normal repartition. These results are compared with other data published in the litterature. We propose a global interpretation, based on a semi-phenomenological model, which involves a broad distribution of relaxation times in the system. The model predicts the power law behavior and the statistical repartition of the mechanical parameters, as experimentally observed for the cells. Moreover, it leads to an estimate of the largest response time in the cytoskeletal network: $\tau_m \approx 1000$ s.Comment: 47 pages, 14 figures // v2: PDF file is now Acrobat Reader 4 (and up) compatible // v3: Minor typos corrected - The presentation of the model have been substantially rewritten (p. 17-18), in order to give more details - Enhanced description of protocols // v4: Minor corrections in the text : the immersion angles are estimated and not measured // v5: Minor typos corrected. Two references were clarifie

Photonic band gaps in materials with triply periodic surfaces and related tubular structures

We calculate the photonic band gap of triply periodic bicontinuous cubic structures and of tubular structures constructed from the skeletal graphs of triply periodic minimal surfaces. The effect of the symmetry and topology of the periodic dielectric structures on the existence and the characteristics of the gaps is discussed. We find that the C(I2-Y**) structure with Ia3d symmetry, a symmetry which is often seen in experimentally realized bicontinuous structures, has a photonic band gap with interesting characteristics. For a dielectric contrast of 11.9 the largest gap is approximately 20% for a volume fraction of the high dielectric material of 25%. The midgap frequency is a factor of 1.5 higher than the one for the (tubular) D and G structures

Na+ imaging reveals little difference in action potential–evoked Na+ influx between axon and soma

Author Posting. © The Authors, 2010. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature Neuroscience 13 (2010): 852-860, doi:10.1038/nn.2574.In cortical pyramidal neurons, the axon initial segment (AIS) plays a pivotal role in synaptic integration. It has been asserted that this property reflects a high density of Na+ channels in AIS. However, we here report that AP–associated Na+ flux, as measured by high–speed fluorescence Na+ imaging, is about 3 times larger in the rat AIS than in the soma. Spike evoked Na+ flux in the AIS and the first node of Ranvier is about the same, and in the basal dendrites it is about 8 times lower. At near threshold voltages persistent Na+ conductance is almost entirely axonal. Finally, we report that on a time scale of seconds, passive diffusion and not pumping is responsible for maintaining transmembrane Na+ gradients in thin axons during high frequency AP firing. In computer simulations, these data were consistent with the known features of AP generation in these neurons.Supported by US– Israel BSF Grant (2003082), Grass Faculty Grant from the MBL, NIH Grant (NS16295), Multiple Sclerosis Society Grant (PP1367), and a fellowship from the Gruss Lipper Foundation