891 research outputs found
Rhythms in the biting behaviour of a mosquito Armigeres subalbatus
The biting cycle of Armigeres subalbatus is distinctly crepuscular, exhibiting two peaks of activity, a smaller one at dawn and a larger one at dusk. The biting cycle is entrained to natural light-dark cycles and the time interval from dawn to dawn or dusk to dusk peaks is exactly 24 h and from dawn to dusk or dusk to dawn is about 12 h measured at 50% level. This rhythm manifests itself day after day without any marked qualitative change. The rate of change of light intensity may determine the onset of crepuscular biting. The sudden increase (up to ca. 17 lx) or decrease (down to ca. 4 lx) in the intensity of ambient light at the time of sunrise or sunset coincides with the peak of the biting activity. The density of the population of the host-seeking females fluctuates in relation to the phases of the moon, increasing with the full moon phase and decreasing with the new moon phase. Even though the density of the population is greater outdoors than indoors both at ground levels and in the first floor, the peak of activity occurs at the same time in all the places. A vertical stratification of biting activity was also noticed
Decision making using modified s-curve membership function in fuzzy linear programming problem
In order to develop approaches to solve a fuzzy linear programming problem, it is necessary to study first the formulation of membership functions and then the methodology for applying the solution to real life problems. A S-curve membership function is proposed in this paper. It is important to note that the S-curve membership function has to be flexible to describe the fuzziness in the problem. Fuzziness may occur in several levels of an industrial production management such as manpower requirements, resource availability such as software and the demand to be met. In order to show that the S-curve membership function works well for fuzzy problems, a numerical example is demonstrated. A thorough study on how the non linear membership function used in dealing with fuzzy parameters and fuzzy constraints is also presented. Only one case where all three coefficients (such as objective coefficients, technical coefficients and resource variables) that normally occur in production planning problem, are considered and fuzzified. However, there are several other cases. The result obtained from this paper is to provide confidence in using the proposed S-curve membership function in a real life production planning industrial problem
Studies on energy transformation in the freshwater snail Pila globosa 1. Influence of feeding rate
The effects of eleven chosen feeding levels ranging from 0 to 198 mg damp dry (plant)
Ceratophyllumlg live snail /day on the absorption, conversion and metabolism of the
snail Pi/a globosa (of 1•9 g body weight) have been studied. Absorption rates increased
from 3•0 to 21•0 mg dry food /g live snail/day in snails fed 3-4-28'8 mg dry food/
g live snail/day. In these snails, absorption efficiency decreased from 87•5 to 73•0 %
Effect of organic fortified zinc on growth and yield of green gram (Vigna radiata (L). Wilczek) in typic chromustert
Zinc is a crucial micronutrient for crop growth and enzymatic regulations. The present study was formulated to reveal the effect of organic fortified Zn composite on growth and yield parameters of green gram in Typic chromustert at Vellakulam village, Kalligudi block, Madurai district of Tamil Nadu. A total of eight treatments with three replications were designed to grow in Randomized Block Design (RBD). The treatments consisted of recommend dose fertilizers (25:50:25 Kg ha-1 N: P2O5: K2O) + various sources organics applied such as vermicompost (1:5), poultry manure (1:5), biochar (1:5), FYM (1:10) incubated with ZnSO4 @ 25 kg ha-1 and Tamil Nadu Agricultural University micronutrient mixture enriched with FYM (1:10) for 30 days. Among the treatments, application of RDF (25:50:25 Kg ha-1 N: P2O5: K2O) + soil application of ZnSO4 @ 25 kg ha-1 incubated with 125 kg Vermicompost (1:5) recorded maximum plant height (64 cm), leaf area index (LAI) (3.11), dry matter production (16.33 g plant-1), pods plant-1 (28.46), grains pod-1 (13.5), test weight (3.48 g), seed yield (950 kg ha-1) and haulm yield (1520 kg ha-1) followed by biochar and TNAU MNM shown on par results with each other. The lowest yield parameters were spotted in absolute control. A considerable increase in yield (25 %) was detected when the crop was supplemented with organically fortified Zinc than the commercial ZnSO4. The study concluded that the application of biofortified Zn will deliver higher growth and yield in green gram
A Sample of Intermediate-Mass Star-Forming Regions: Making Stars at Mass Column Densities <1 g/cm^2
In an effort to understand the factors that govern the transition from low-
to high-mass star formation, we identify for the first time a sample of
intermediate-mass star-forming regions (IM SFRs) where stars up to - but not
exceeding - 8 solar masses are being produced. We use IRAS colors and Spitzer
Space Telescope mid-IR images, in conjunction with millimeter continuum and CO
maps, to compile a sample of 50 IM SFRs in the inner Galaxy. These are likely
to be precursors to Herbig AeBe stars and their associated clusters of low-mass
stars. IM SFRs constitute embedded clusters at an early evolutionary stage akin
to compact HII regions, but they lack the massive ionizing central star(s). The
photodissociation regions that demarcate IM SFRs have typical diameters of ~1
pc and luminosities of ~10^4 solar luminosities, making them an order of
magnitude less luminous than (ultra)compact HII regions. IM SFRs coincide with
molecular clumps of mass ~10^3 solar masses which, in turn, lie within larger
molecular clouds spanning the lower end of the giant molecular cloud mass
range, 10^4-10^5 solar masses. The IR luminosity and associated molecular mass
of IM SFRs are correlated, consistent with the known luminosity-mass
relationship of compact HII regions. Peak mass column densities within IM SFRs
are ~0.1-0.5 g/cm^2, a factor of several lower than ultra-compact HII regions,
supporting the proposition that there is a threshold for massive star formation
at ~1 g/cm^2.Comment: 61 pages, 6 tables, 20 figures. Accepted for publication in the
Astronomical Journa
Agricultural bio-waste recycling through efficient microbial consortia
In India and other countries, rice straw, a byproduct of rice production, is burned in enormous amounts, which contributes to environmental pollution and climate change by releasing greenhouse gases viz., CO2, N2O, CH4, into the atmosphere. This study aimed to accelerate the degradation of this enormous amount of agricultural biomass via microbial inoculants. Four treatments—rice straw (RS), rice straw plus water (RSW), rice straw plus water plus Pusa decomposer (RSWF), and rice straw plus water plus Tamil Nadu Agricultural University (TNAU) biomineralizer (RSWB) were used in the current investigation. The study's findings demonstrated that rice straw treated with microorganisms decomposed more quickly than RS and RSW treatments. According to EDAX spectra of elemental composition, the carbon content of rice straw in the RS, RSW, RSWF, and RSWB treatments was 33.66%, 29.75%, 13.33%, and 20.65% w/w, respectively. The RSWF treatment of rice straw was found to have the highest nitrogen concentration (0.64% w/w), followed by RSWB (0.61% w/w), RSW (0.45%) w/w, and RS (0.43% w/w). Treatments RSWF and RSWB had lower C/N ratios 20.83, and 33.85, respectively, than that RSW (66.11) and RS (78.28). The RSWF and RSWB treatments' porous, distorted, and rough surface structures provided further evidence that both microbial consortia could decompose rice straw more quickly than the RSW and RS treatments. Therefore, the results of this study imply that rice straw could be added to the soil to improve soil fertility for sustainable crop production rather than being burned
Characterizing star formation activity in infrared dark cloud MSXDC G048.65-00.29
Infrared Dark Clouds (IRDCs), condensed regions of the ISM with high column
densities, low temperatures and high masses, are suspected sites of star
formation. Thousands of IRDCs have already been identified. To date, it has not
been resolved whether IRDCs always show star formation activity and, if so, if
massive star formation (> 8 solar masses) is the rule or the exception in
IRDCs. Previous analysis of sub-millimeter cores in the cloud MSXDC
G048.65-00.29 (G48.65) indicates embedded star formation activity. To
characterize this activity in detail, mid-infrared photometry (3-30 micron) has
been obtained with the Spitzer Space Telescope. This paper analyzes the point
sources seen in the 24 micron band, combined with counterparts or upper limits
at shorter and longer wavelengths. Data points in wavelength bands ranging from
1 up to 850 micron are used to compare each 24 micron source to a set of
Spectral Energy Distributions of Young Stellar Object (YSO) models. By
assessing the models that fit the data, an attempt is made to identify YSOs as
such and determine their evolutionary stages and stellar masses. A total of 17
sources are investigated, 13 of which are classified as YSOs, primarily - but
not exclusively - in an early embedded phase of star formation. The modeled
masses of the central stellar objects range from sub-solar to ~8 solar masses.
Every YSO is at less than 1 pc projected distance from its nearest YSO
neighbor. We conclude that IRDC G48.65 is a region of active star formation. We
find YSOs in various evolutionary phases, indicating that the star formation in
this cloud is not an instantaneous process. The inferred masses of the central
objects suggest that this IRDC hosts only low to intermediate mass YSOs and
none with masses exceeding ~8 solar masses.Comment: 10 pages, 6 figures; v2: minor editorial changes to match published
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