Experimental investigation of the excess charge and time constant of minority carriers in the thin diffused layer of 0.1 ohm-cm silicon solar cells

An experimental method is presented that can be used to interpret the relative roles of bandgap narrowing and recombination processes in the diffused layer. This method involves measuring the device time constant by open-circuit voltage decay and the base region diffusion length by X-ray excitation. A unique illuminated diode method is used to obtain the diode saturation current. These data are interpreted using a simple model to determine individually the minority carrier lifetime and the excess charge. These parameters are then used to infer the relative importance of bandgap narrowing and recombination processes in the diffused layer

Mifepristone versus intracervical prostaglandin E2 gel for cervical ripening in primigravid patients at term

Background: The cervix has to play dual role in human reproduction. During pregnancy, it should remain firm and closed allowing the fetus to grow in utero until functional maturity is attained while during labour it should soften and dilate, allowing the fetus to pass through the birth canal. Objective of present study was to know and compare the effect of oral Mifepristone with intracervical dinoprostone gel for cervical priming prior to induction of labour at term in an unfavorable cervix of primigravida.Methods: This was prospective randomized comparative study. 100 primigravid patients were included, 50 were placed in each group A and B. Tablet Mifepristone 200mg orally was given in group A patients and intracervical dinoprostone gel induction was done in group B patients. Pre induction Bishop’s score was noted at beginning to compare improvement in Bishop’s score after induction. Mode of delivery and induction to delivery interval in both the groups were studied.Results: After induction with Mifepristone 76% women had successful cervical ripening as compared to 56% with dinoprostone. Rate of vaginal delivery was 70% with Mifepristone and 58% with dinoprostone. There was no significant difference in induction to delivery interval between the groups. Ten percent and 2% belonging to mifepristone and dinoprostone group respectively, required NICU admissions.Conclusions: Mifepristone is more effective than dinoprostone for preinduction cervical ripening as it has high success rate of achieving cervical ripening, however there is no significant difference in the vaginal delivery rate and other maternal and fetal outcome

Fluctuation induces evolutionary branching in a modeled microbial ecosystem

The impact of environmental fluctuation on species diversity is studied with a model of the evolutionary ecology of microorganisms. We show that environmental fluctuation induces evolutionary branching and assures the consequential coexistence of multiple species. Pairwise invasibility analysis is applied to illustrate the speciation process. We also discuss how fluctuation affects species diversity.Comment: 4 pages, 4 figures. Submitted to Physical Review Letter

Patterns, spin-spin correlations and competing instabilities in driven quasi-two-dimensional spin-1 Bose-Einstein condensates

We analyze the formation of transient patterns and spin-spin correlations in quasi-two-dimensional spin-1 homogeneous Bose-Einstein condensates subjected to parametric driving of $s$-wave scattering lengths. The dynamics for an initial ferromagnetic phase is identical to that of a scalar condensate. In contrast, intriguing dynamics emerges for an initial polar state. For instance, we show that competition exists between density patterns and spin-mixing dynamics. Dominant spin-mixing dynamics lead to a gas of polar core vortices and anti-vortices of different spin textures. The density modes of the Bogoliubov spectrum govern the wavenumber selection of Faraday patterns. The spin modes determine the vortex density and the spatial dependence of spin-spin correlation functions. When the density patterns outgrow the spin-mixing dynamics, the spin-spin correlations decay exponentially with a correlation length of the order a spin healing length; otherwise, they exhibit a Bessel function dependence. Strikingly, competing instabilities within density and spin modes emerge when both scattering lengths are modulated at different frequencies and appropriate modulation amplitudes. The competing instability leads to a superposition of density patterns or correlation functions of two distinct wavelengths. Our studies reveal that fine control over the driven dynamics can be attained by tuning interaction strengths, quadratic Zeeman field, driving frequencies, and amplitudes.Comment: 11 pages, 13 figure

Seed source variation and conservation of Pinus wallichiana in India

Pinus wallichiana A.B. Jacks is an important component of the middleand high altitude Himalayan forests having large natural distribution ranging between 260 to 360 N latitude and 690 to 750 E longitudes. It is commonly known as Himalayan blue pine or blue pine, being indigenous to Himalayan Mountain regions and because of its bluish or grayish-green leaves. It is a five needle pine which gained world-wide attention for its resistance to blister rust among white pines. This species has been crossed successfully with other white pines and vigorous hybrids have been obtained. Considerable variation in morphological and anatomical characteristics of needles, cones and seeds in natural stands exists across the natural distribution of the species, especially in mesic and xeric habitats. These variationssuggested the differentiation of this species in ecotypes or varieties as reported by various authors. However, the level of genetic diversity was found to be relatively high and the degree of genetic differentiation was low compared to other pines. Thewide range of climatic conditions in the natural distribution of this pine is expected to result in high genetic variation within different populations of the species. The study aims to determine the nature and extent of variation present in the populations of the species in respect to cone and seed characteristics across its natural distribution. Seed of 17 seed sources from the states of Uttaranchal and Himachal Pradesh was collected and analyzed for cone characters (fresh weight of cones, cone length, cone width, specific gravity) and seed characters (seed weight, moisture content, germination percent, cotyledon number). Significant variations have beenobserved in these traits among different seed sources of the species. The cone weight varied from 44.4 to114g and the higher cone weight was recorded at higher altitudes.The germination percent varied from 40 to 85 whereas cotyledon number varied from 7 to12. Seed weight ranged from 35.70 to 69.30g in all seed sources. These variations can be utilized further in identifying the best seed sources in improving the productivity of the species. The genetic variability present in this pine has been conserved in preservation plots demarcated and maintained in its natural ranges ofdistribution in the country, since the early 19th century

A cartilage growth mixture model for infinitesimal strains: solutions of boundary-value problems related to in vitro growth experiments

A cartilage growth mixture (CGM) model is linearized for infinitesimal elastic and growth strains. Parametric studies for equilibrium and nonequilibrium boundary-value problems representing the in vitro growth of cylindrical cartilage constructs are solved. The results show that the CGM model is capable of describing the main biomechanical features of cartilage growth. The solutions to the equilibrium problems reveal that tissue composition, constituent pre-stresses, and geometry depend on collagen remodeling activity, growth symmetry, and differential growth. Also, nonhomogeneous growth leads to nonhomogeneous tissue composition and constituent pre-stresses. The solution to the nonequilibrium problem reveals that the tissue is nearly in equilibrium at all time points. The results suggest that the CGM model may be used in the design of tissue engineered cartilage constructs for the repair of cartilage defects; for example, to predict how dynamic mechanical loading affects the development of nonuniform properties during in vitro growth. Furthermore, the results lay the foundation for future analyses with nonlinear models that are needed to develop realistic models of cartilage growth

Grasspea: A Potential Fodder and Feed Resources

Grasspea (Lathyrus sativus L.) is a an important legume crop grown in India, Bangladesh, China, Ethiopia, Nepal, and Pakistan for human food, animal feed and soil health improvement. In India, grasspea is grown in about 521,100 ha, mainly in Chhattisgarh, Bihar, Jharkhand, Maharashtra, Orissa, Assam, West Bengal, and eastern Uttar Pradesh. Grasspea cultivation is low-cost and easy. Inherently grasspea possesses resistance to drought, excess moisture, salinity, diseases, and insect pests. As grasspea has an ambivalent reputation due to ODAP content in its plant parts, efforts are on to develop low or ODAP-free grasspea varieties with high biomass for dual purpose for human food and animal feed. A number of such varieties are now available in India, Bangladesh, Nepal and Ethiopia. Grasspea is known as excellent feed and fodder crop for centuries as a main concentrate for horses (Anonymous, 1894). Livestock is a key component of farming systems in South Asia and in Africa, and most particularly with small and marginal farmers, estimated about 678 million, and indicates importance of livestock to their livelihoods (ILRI, 2000)

Location and function of the slow afterhyperpolarization channels in the basolateral amygdala

The basolateral amygdala (BLA) assigns emotional significance to sensory stimuli. This association results in a change in the output (action potentials) of BLA projection neurons in response to the stimulus. Neuronal output is controlled by the intrinsic excitability of the neuron. A major determinant of intrinsic excitability in these neurons is the slow after hyperpolarization (sAHP) that follows action potential (AP) trains and produces spike-frequency adaptation. The sAHP is mediated by a slow calcium-activated potassium current (sI(AHP)), but little is known about the channels that underlie this current. Here, using whole-cell patch-clamp recordings and high-speed calcium imaging from rat BLA projection neurons, we examined the location and function of these channels. We determined the location of the sI(AHP) by applying a hyperpolarizing voltage step during the sI(AHP) and measuring the time needed for the current to adapt to the new command potential, a function of its electrotonic distance from the somatic recording electrode. Channel location was also probed by focally uncaging calcium using a UV laser. Both methodologies indicated that, in BLA neurons, the sI(AHP) is primarily located in the dendritic tree. EPSPs recorded at the soma were smaller, decayed faster, and showed less summation during the sAHP. Adrenergic stimulation and buffering calcium reduced the sAHP and the attenuation of the EPSP during the sAHP. The sAHP also modulated the AP in the dendrite, reducing the calcium response evoked by a single AP. Thus, in addition to mediating spike-frequency adaptation, the sI(AHP) modulates communication between the soma and the dendrite