Entropy and Barrier-Hopping Determine Conformational Viscoelasticity in Single Biomolecules

Biological macromolecules have complex and non-trivial energy landscapes, endowing them a unique conformational adaptability and diversity in function. Hence, understanding the processes of elasticity and dissipation at the nanoscale is important to molecular biology and also emerging fields such as nanotechnology. Here we analyse single molecule fluctuations in an atomic force microscope (AFM) experiment using a generic model of biopolymer viscoelasticity that importantly includes sources of local `internal' conformational dissipation. Comparing two biopolymers, dextran and cellulose, polysaccharides with and without the well-known `chair-to-boat' transition, reveals a signature of this simple conformational change as minima in both the elasticity and internal friction around a characteristic force. A calculation of two-state populations dynamics offers a simple explanation in terms of an elasticity driven by the entropy, and friction by barrier-controlled hopping, of populations on a landscape. The microscopic model, allows quantitative mapping of features of the energy landscape, revealing unexpectedly slow dynamics, suggestive of an underlying roughness to the free energy.Comment: 25 pages, 7 figures, naturemag.bst, modified nature.cls (naturemodified.cls

RIVER ECOLOGICAL STUDY: BUILDING THE KNOWLEDGE BASE FOR VARIETY OF ASSESSMENTS SUCH AS CLIMATE CHANGE IN NEPAL

Climate change is now universally acknowledged to be taking place across the globe. It is generally presumed that the impacts of climate change would be more severe in the country like Nepal due to its location, physiography, poverty and lack of preparedness to cope with the changes. The last reason is mainly associated with knowledge, information and ability to use technologies based on science.The main objective of this research is to analyze and evaluate the effects of climate change by taking fish as an indicator. However, an even more important outcome is to prepare a solid foundation of fish-based information, which could be used in the future as a reference for a variety of purposes including the study of climate change. Two sets of examples, one in the tributaries of a glacial river and another in the tributary of a rain -fed river are compared in terms of fish ecological attributes to test for effects of climate change. In addition to fish-based information, this research also studies physico-chemical parameters and benthic fauna so as to build up an ecological profile of the rivers

Factors Affecting the Productivity of Coffee in Gulmi and Arghakhanchi Districts of Nepal

Coffee is one of the major potential cash crops with lucrative export value grown in mid-hills of Nepal. Nepalese coffee production has suffered long by low productivity. Research was conducted from February to May, 2019 to analyze the factors affecting the productivity of coffee in Arghakhanchi and Gulmi districts of Nepal. These two districts were, purposively selected for this study taking account of comparative advantage and past studies recommendations for coffee sector. Altogether, 100 coffee growing households 50 from each, Arghakhanchi and Gulmi, were sampled by using multistage sampling technique. A pre-tested semi-structured interview schedule was used to collect the primary information while secondary information was collected reviewing the relevant publications. Ordinary Least Square (OLS) regression model was used to determine the factors affecting the productivity of coffee. The study revealed that the number of active family members involved in coffee production (0.000), adoption of income diversification through intercropping (0.005), training (0.072) and technical assistance (0.021) had positive and significant effect on coffee productivity. Encouraging the household to have coffee production as their primary occupation, providing technical assistance on rational land utilization and intercropping and strengthening the skill and knowledge of farmers through trainings could significantly support in increasing the productivity of coffee

A study of prevalence and seasonal trends of different malarial species in district hospital

Background: Malaria imposes great socio-economic burden on humanity. In India, the epidemiology of malaria is complex because of wide distribution of anopheline vectors which transmitting mainly two Plasmodial species named P. falciparum and P. vivax. Though India is one of the known endemic countries, incidence of malaria is commonly influenced by environmental factors like climate, season, temperature and socioeconomic status. Objectives of the study were to know the prevalence of different malarial species and to know the seasonal trend of malaria.Methods: This study done microbiology department of district hospital over period of June 2015 to December 2015. We had collected total 6763 samples. We used Microscopic examination for the diagnosis of malaria by preparing thick and thin smears and stained using field stain.Results: We had collected total 6763 samples out of which 108 samples are found microscopically positive (1.5%). In our hospital we observed only Plasmodium vivax and Plasmodium falciparum spp. Prevalence of P. vivax (64%) found more compare to P. falciparum (34%) and peak positivity rate found in July to October.Conclusions: In our study the most frequently implicated species was P. vivax. This indicates that P. vivax is the most widespread infection in India which results in a pronounced morbidity and the seasonal prevalence observed high in July to October. In order to implement effective preventive measures, proper surveillance on the incidence and prevalence of malaria is required

Surface Defect incorporated Diamond Machining of Silicon

This paper reports the performance enhancement benefits in diamond turning of the silicon wafer by incorporation of the Surface Defect Machining (SDM) method. The hybrid micromachining methods usually require additional hardware to leverage the added advantage of hybrid technologies such as laser heating, cryogenic cooling, electric pulse or ultrasonic elliptical vibration. The SDM method tested in this paper does not require any such additional baggage and is easy to implement in a sequential micro-machining mode. This paper made use of Raman spectroscopy data, average surface roughness data and imaging data of the cutting chips of silicon for drawing a comparison between conventional Single Point Diamond Turning (SPDT) and SDM while incorporating surface defects in the (i) circumferential and (ii) radial directions. Complimentary 3D Finite Element Analysis (FEA) was performed to analyse the cutting forces and the evolution of residual stress on the machined wafer. It was found that the surface defects generated in the circumferential direction with an interspacing of 1 mm revealed the lowest average surface roughness (Ra) of 3.2 nm as opposed to 8 nm Ra obtained through conventional SPDT using the same cutting parameters. The observation of the Raman spectroscopy performed on the cutting chips showed remnants of phase transformation during the micromachining process in all cases. FEA was used to extract quantifiable information about the residual stress as well as the sub-surface integrity and it was discovered that the grooves made in the circumferential direction gave the best machining performance. The information being reported here is expected to provide an avalanche of opportunities in the SPDT area for low-cost machining solution for a range of other nominal hard, brittle materials such as SiC, ZnSe and GaAs as well as hard steels

Determining Specific Window Period for Common Scab Disease Infection in Potato Tubers

A series of experiments was conducted under glasshouse and hydroponic conditions to determine the specific window period for common scab disease infection in potato tubers. The study was performed in a glasshouse system where separate tubers from the root zone were inoculated at different intervals during plant growth along with a novel hydroponic system to inoculate individual tubers at specific times of development growth allowing non-destructive observations of common scab symptoms developing. The window of tuber susceptibility to common scab disease infection was shown to vary with the season or conditions under which the plants were grown. Different internodes on tubers were found susceptible to infection at different times during tuber development. Basal internodes, which are the first sections of the tuber to expand, were susceptible to infection in the beginning of tuber development, whereas apical internodes only became susceptible later in tuber growth when the basal internodes were no longer susceptible.Journal of Nepal Agricultural Research Council Vol.3 2017: 19-2

Computation using Noise-based Logic: Efficient String Verification over a Slow Communication Channel

Utilizing the hyperspace of noise-based logic, we show two string verification methods with low communication complexity. One of them is based on continuum noise-based logic. The other one utilizes noise-based logic with random telegraph signals where a mathematical analysis of the error probability is also given. The last operation can also be interpreted as computing universal hash functions with noise-based logic and using them for string comparison. To find out with 10^-25 error probability that two strings with arbitrary length are different (this value is similar to the error probability of an idealistic gate in today's computer) Alice and Bob need to compare only 83 bits of the noise-based hyperspace.Comment: Accepted for publication in European Journal of Physics B (November 10, 2010

Analysis of Yield Attributing Characters of Different Genotypes of Wheat in Rupandehi, Nepal

Field experiment was conducted at National Wheat Research Program, Bhairahawa, Rupandehi with the objective to identify high yielding superior wheat genotypes for Rupandehi district of Nepalduring 2014. Experiment was laid out in one factorial Randomized completely block design with ten wheat genotypes including both released and promising; Annapurna 1, Annapurna 3, Pasang Lahmu, Bijaya, BL 3623, Bhirkuti, NL 297, BL 4316, BL 3978 and BL 4347with three replications. The results showed that the grain yield of BL 3978 was found higher (4.03 t ha-1) than other genotypes followed by BL 4347 (3.93t ha-1). BL 3978 have also higher number of effective tillers m-2 and test weight. Among release varieties, NL 297 show higher yield (4 t ha-1) followed by Bhirkuti (3.43 t ha-1)and Bijaya (3.37 t ha-1). From this experiment it can be concluded that BL 3978 was found promising among all genotypes however should be tested at on-farms before promoted for general cultivation in Rupandehi district of Nepal

Free-vibration Characteristics of Laminated Angle-ply Non-circular Cylindrical Shells

This paper deals with the free-vibration behaviour of anisotropic laminated angle-ply noncircular cylindrical shells using finite element approach. The formulation is based on first-ordershear deformation theory. The present model accounts for in-plane and rotary inertia effects. A detailed study has been carried out to highlight the effects of shell geometry, cross-sectionalproperties, lay-up and ply-angles on the natural frequencies of different types of modes of vibration of non-circular elliptical shell structures