756 research outputs found
Optimal conditions for tissue growth and branch induction of Gracilariopsis persica
The species Gracilariopsis persica was first described by Bellorin et al. (2008). G. persica grows from late September to July and shows high growth rate from January to May in the Persian Gulf. Tissue growth and branch induction of red seaweed, Gracilariopsis persica from the Persian Gulf investigated under various culture levels of temperature, light intensity, photoperiod, salinity, initial length, propagule density and chemical preservatives. Optimal size of propagules used as seed was 2 cm and faster growth of tissue and branch induction obtained at lower density. The apical part of the G. persica showed as the starting point of growth. The G. persica showed optimal growth in PES medium at 24°C, 60μmol m-2 s-1 light intensity, 12L: 12D and salinity of 39‰. But maximum branch production occurred under condition of 24°C, 20 μmol m-2 s-1 light intensity, photoperiod of 16L: 8D and salinity 39‰. Addition of chemical preservatives of p-hydroxybenzoic acid and potassium sorbate in culture medium showed marginal suppression on tissue growth and branch induction, that suitable for preparation of semi-axenic culture condition
Methodology to determine the extent of anaerobic digestion, composting and CH4 oxidation in a landfill environment
Abstract: An examination of the processes contributing to the production of landfill greenhouse gas (GHG) emissions is required, as the actual level to which waste degrades anaerobically and aerobically beneath covers has not been differentiated. This paper presents a methodology to distinguish between the rate of anaerobic digestion (rAD), composting (rCOM) and CH4 oxidation (rOX) in a landfill environment, by means of a system of mass balances developed for molecular species (CH4, CO2) and stable carbon isotopes (δ13C-CO2 and δ13C-CH4). The technique was applied at two sampling locations on a sloped area of landfill. Four sampling rounds were performed over an 18 month period after a 1.0 m layer of fresh waste and 30-50 cm of silty clay loam had been placed over the area. Static chambers were used to measure the flux of the molecular and isotope species at the surface and soil gas probes were used to collect gas samples at depths of approximately 0.5, 1.0 and 1.5 m. Mass balances were based on the surface flux and the concentration of the molecular and isotopic species at the deepest sampling depth. The sensitivity of calculated rates was considered by randomly varying stoichiometric and isotopic parameters by ±5% to generate at least 500 calculations of rOX, rAD and rCOM for each location in each sampling round. The resulting average value of rAD and rCOM indicated anaerobic digestion and composting were equally dominant at both locations. Average values of rCOM: ranged from 9.8 to 44.5 g CO2 m-2 d-1 over the four sampling rounds, declining monotonically at one site and rising then falling at the other. Average values of rAD: ranged from 10.6 to 45.3 g CO2 m-2 d-1. Although the highest average rAD value occurred in the initial sampling round, all subsequent rAD values fell between 10 and 20 g CO2 m-2 d-1. rOX had the smallest activity contribution at both sites, with averages ranging from 1.6 to 8.6 g CO2 m-2 d-1. This study has demonstrated that for an interim cover, composting and anaerobic digestion of shallow landfill waste can occur simultaneously
Population density and spatial distribution pattern of Hypera postica (Coleoptera: Curculionidae) in Ardabil, Iran
The alfalfa weevil, Hypera postica (Gyllenhal), feeds almost exclusively on alfalfa, Medicago saliva L. in most region of the world where forage crop is grown. It has been investigated the population density and spatial distribution of alfalfa weevil on alfalfa in Ardabil during 2010. Using a 0.25 m(2) quadrate sample unit a reliable sample size was 65, with maximum relative variation of 15%. The relative variation (RV) of the primary sampling data was 13.6. The highest population density of the alfalfa weevil was recorded on 17(th) April. To estimate the spatial distribution pattern of this pest, data were analyzed through index of dispersion. Lloyd's mean crowding. Morisita's index and two regression models (Taylor's Power Law and Iwao's Patchiness Regression). Taylor's model showed an aggregated distribution pattern for all life stages. Iwao's patchiness regression indicated that larvae, adult and total life cycle had aggregated spatial distribution (t(c
Energy use pattern and sensitivity analysis of rice production: A case study of Guilane province of Iran
Rice is one of the most important crop supplying the world's
population's food. Because of the direct links between energy and crop
yields, and food supplies, rice energy analysis is essential. The
objective of this study was to evaluate the energy balance between
inputs and outputs of rice production in Guilane Province of Iran. Data
were collected from 105 rice farmers with face to face questionnaire. A
total energy input and output of 39.3 and 60.3 G J ha-1 was observed.
Fertiliser and fuel were the highest energy inputs with amount of 14.1
and 11.6 G J ha-1, followed by electricity and seed with 5.2 and 3.1 G
J ha-1, respectively. Energy use efficiency, energy productivity,
specific energy and net energy were 1.57, 0.09, 11.20 and 21 G J ha-1,
respectively. The share of non-renewable energy was almost 89%, while
the direct and indirect energy usage based on inputs was approximately
equal (49 and 51%, respectively). The econometric model showed that
fuel and machinery had a significant effect on rice yield. The marginal
physical productivity (MPP) value of fuel and machinery was 0.93 and
0.23, respectively. The total cost of production, gross and net returns
were 3156, 1629 and 927 US ha-1, respectively. The benefit-cost ratio
was calculated to be 1.29.Le riz est parmi d'importantes cultures qui fournissent de la
nourriture aux populations du monde. A cause des liens directs entre
l'\ue9nergie et les rendements de cultures, l'analyse de
l'\ue9nergie pour le riz est primordial. L'objectif de cette
\ue9tude \ue9tait d'\ue9valuer la balance \ue9nerg\ue9tique
entre apports et sorties de la production du riz dans la Province de
Guilane en Iran. De donn\ue9es \ue9taient recuillies de 105
riziculteurs \ue0 l'aide d'un questionnaire face \ue0 face. Un
total d'apport et sortie d'\ue9nergie de 39.3 et 60.3 G J ha-1
\ue9tait respectivement observ\ue9. Les fertilisants et le
carburant constituaient un apport plus \ue9lev\ue9 d'\ue9nergie
de l'ordre de 14.1 et 11.6 G J ha-1 suivis de l'\ue9lecticit\ue9 et
semence avec 5.2 et 3.1 G J ha-1, respectivement. L'utilisation
efficiente de l'\ue9nergie, la productivit\ue9 de l'\ue9nergie,
l'\ue9nergie sp\ue9cifique et l' \ue9nergie nette \ue9taient de
1.57, 0.09, 11.20 et 21 G J ha-1, respectivement. La part de
l'\ue9nergie non renouvelable \ue9tait d'environ 89%, pendant que
l'usage direct et indirect de l'\ue9nergie bas\ue9 sur les apports
\ue9tait approximativement \ue9gal (49 et 51%, respectivement). Le
mod\ue8le \ue9conom\ue9trique avait montr\ue9 que le carburant
et les machines avaient 0.93 et 0.23, respectivement. Le co\ufbt
total de production, le gros et le revenu net \ue9taient de 3156,
1629 et 927 US ha-1, respectivement. Le rapport
co\ufbt-b\ue9n\ue9fice calcul\ue9 \ue9tait de 1.29
Energy use pattern and sensitivity analysis of rice production: A case study of Guilane province of Iran
Rice is one of the most important crop supplying the world’s population’s food. Because of the direct links between energy and crop yields, and food supplies, rice energy analysis is essential. The objective of this study was to evaluate the energy balance between inputs and outputs of rice production in Guilane Province of Iran. Data were collected from 105 rice farmers with face to face questionnaire. A total energy input and output of 39.3 and 60.3 G J ha-1 was observed. Fertiliser and fuel were the highest energy inputs with amount of 14.1 and 11.6 G J ha-1, followed by electricity and seed with 5.2 and 3.1 G J ha-1, respectively. Energy use efficiency, energy productivity, specific energy and net energy were 1.57, 0.09, 11.20 and 21 G J ha-1, respectively. The share of non-renewable energy was almost 89%, while the direct and indirect energy usage based on inputs was approximately equal (49 and 51%, respectively). The econometric model showed that fuel and machinery had a significant effect on rice yield. The marginal physical productivity (MPP) value of fuel and machinery was 0.93 and 0.23, respectively. The total cost of production, gross and net returns were 3156, 1629 and 927 US $ ha-1, respectively. The benefit-cost ratio was calculated to be 1.29
Localized Surface Plasmon Resonance as a Biosensing Platform for Developing Countries
The discovery of the phenomena known as localized surface plasmon resonance (LSPR) has provided the basis for many research areas, ranging from materials science to biosensing. LSPR has since been viewed as a transduction platform that could yield affordable, portable devices for a multitude of applications. This review aims to outline the potential applications within developing countries and the challenges that are likely to be faced before the technology can be effectively employed
Cyclosporin A differentially inhibits multiple steps in VEGF induced angiogenesis in human microvascular endothelial cells through altered intracellular signaling
The immunosuppressive agent cyclosporin A (CsA), a calcineurin inhibitor which blocks T cell activation has provided the pharmacologic foundation for organ transplantation. CsA exerts additional effects on non-immune cell populations and may adversely effect microvascular endothelial cells, contributing to chronic rejection, a long-term clinical complication and significant cause of mortality in solid-organ transplants, including patients with small bowel allografts. Growth of new blood vessels, or angiogenesis, is a critical homeostatic mechanism in organs and tissues, and regulates vascular populations in response to physiologic requirements. We hypothesized that CsA would inhibit the angiogenic capacity of human gut microvessels. Primary cultures of human intestinal microvascular endothelial cells (HIMEC) were used to evaluate CsA's effect on four in vitro measures of angiogenesis, including endothelial stress fiber assembly, migration, proliferation and tube formation, in response to the endothelial growth factor VEGF. We characterized the effect of CsA on intracellular signaling mechanisms following VEGF stimulation. CsA affected all VEGF induced angiogenic events assessed in HIMEC. CsA differentially inhibited signaling pathways which mediated distinct steps of the angiogenic process. CsA blocked VEGF induced nuclear translocation of the transcription factor NFAT, activation of p44/42 MAPK, and partially inhibited JNK and p38 MAPK. CsA differentially affected signaling cascades in a dose dependent fashion and completely blocked expression of COX-2, which was integrally linked to HIMEC angiogenesis. These data suggest that CsA inhibits the ability of microvascular endothelial cells to undergo angiogenesis, impairing vascular homeostatic mechanisms and contributing to the vasculopathy associated with chronic rejection
A discrete geometric approach for simulating the dynamics of thin viscous threads
We present a numerical model for the dynamics of thin viscous threads based
on a discrete, Lagrangian formulation of the smooth equations. The model makes
use of a condensed set of coordinates, called the centerline/spin
representation: the kinematical constraints linking the centerline's tangent to
the orientation of the material frame is used to eliminate two out of three
degrees of freedom associated with rotations. Based on a description of twist
inspired from discrete differential geometry and from variational principles,
we build a full-fledged discrete viscous thread model, which includes in
particular a discrete representation of the internal viscous stress.
Consistency of the discrete model with the classical, smooth equations is
established formally in the limit of a vanishing discretization length. The
discrete models lends itself naturally to numerical implementation. Our
numerical method is validated against reference solutions for steady coiling.
The method makes it possible to simulate the unsteady behavior of thin viscous
jets in a robust and efficient way, including the combined effects of inertia,
stretching, bending, twisting, large rotations and surface tension
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