Insights into the Fresh Vegetable Sector in Saskatchewan

Saskatchewan has good growing conditions, much land and water resources, minimal pest pressure and the expertise necessary for growing high-quality commercial vegetables. Statistics show, however, that commercial vegetable production occupies a relatively small place in the agricultural economy of Saskatchewan. Saskatchewan production accounts for less than 10 per cent of the total provincial market for fresh vegetables, the other supplies of fresh vegetables marketed in Saskatchewan come from sources outside of the province and imports from the southern United States, Mexico, and other warm regions. The majority of Saskatchewan produced vegetables are sold through market gardens, farmers’ markets and consumer contract sales. In light of the increasing importance of fresh vegetable demand, examining the role of a new marketing organization in the province is important as it might bring about major realignment of the Saskatchewan fresh produce market. Recently, a project supported by the Agriculture Council of Saskatchewan Inc. (ACS) encouraged producers to organize themselves into picking zones and to work together to supply larger retail markets. The Grocery People (TGP) (a retailer) has agreed to purchase vegetables grown in Saskatchewan for their distribution centre in Saskatoon. This new organization, Prairie Fresh Food Corporation (PFFC), despite its numerous benefits, will test the farmer participants’ resolve to cooperate rather than proceed alone. This poses a real opportunity for producers to expand and develop the infrastructure required, as produce can be pooled. This study uses Transaction Cost, Agency and Monopolistic Competition theories to analyze the factors that hamper farmers from participating in contracts and taking advantage of these potential opportunities. It considers the advantages and barriers or potential challenges to wholesalers and retailers cooperating with this plan. In particular, an economic model of economies of scale through collective action is developed. The model assumes that small growers can access higher market share through collective action and achieving economies of scale. The results of personal interviews with eleven members of PFFC are presented and analyzed in a case study format. The case study analysis of PFFC reveals that the organization could provide positive benefits to its members in the early period of its establishment. The results show that the market share of the PFFC is still relatively small throughout the province, but its members expect it to expand in the future. The results suggest that high relative prices in the market and trust in the buyer have a positive effect on the probability of farmer participation in the project

A Healthy and Ecologically Balanced Environment: An Argument for a Third Generation Right

Chymotrypsin-like serine proteases are found in high abundance in mast cell granules. By site-directed mutatgenesis, we have previously shown that basic amino acids in positions 143 and 192 (Arg and Lys respectively) of the human mast cell chymase are responsible for an acidic amino acid residue preference in the P2' position of substrates. In order to study the influence of these two residues in determining the specificity of chymase inhibitors, we have synthesized five different potent inhibitors of the human chymase. The inhibitory effects of these compounds were tested against the wild-type enzyme, against two single mutants Arg143Gln and Lys192Met and against a double mutant, Arg143Gln+Lys192Met. We observed a markedly reduced activity of all five inhibitors with the double mutant, indicating that these two basic residues are involved in conferring the specificity of these inhibitors. The single mutants showed an intermediate phenotype, with the strongest effect on the inhibitor by the mutation in Lys192. The Lys192 and the double mutations also affected the rate of cleavage of angiotensin I but did not seem to affect the specificity in the cleavage of the Tyr(4)-Ile(5) bond. A more detailed knowledge about which amino acids that confer the specificity of an enzyme can prove to be of major importance for development of highly specific inhibitors for the human chymase and other medically important enzymes

Developing equations for estimating reference evapotranspiration in Australia

Quantifying reference evapotranspiration (ET0) is essential in water resources management. Although, many methods have been developed with different level of accuracy, in this study, two new equations were developed and optimized for estimating ET0 using Honey-Bee Mating Optimization (HBMO) algorithm. The firs eq. estimates ET0 from extraterrestrial radiation (Ra), relative humidity (RH) and mean daily temperature (Tmean), while the second uses the same parameters except that mean daily temperatures is replaced with maximum daily air temperature (Tmax). Both equations were developed using climatic data from eight weather stations in Western Australia and subsequently verified using data from ten sites across Australia. The estimated ET0 values from both equations versus the FAO56-Penman-Monteith have a coefficient of determination, R2, of larger than 0.96. Moreover, the performance of six commonly used methods of estimating ET0 including Hargreaves-Samani, Thornthwaith, Hamon, McGuinness-Bordne, Irmak and Jensen-Haise were assessed and the Hargreaves-Samani method performed better than others. An attempt was made to calibrate the Hargreaves-Samani equation; however, its overall performance did not improve and the two newly proposed equations are suggested to be used in Australi

Removal of turbidity from water by dissolved air flotation and conventional sedimentation systems using poly aluminum chloride as coagulant

Flotation is a method in which particles in liquid phase are transported to the surface by air bubbles. In this experimental study, a comparison has been made between conventional sedimentation and dissolved air flotation (DAF) systems to remove turbidity from water. Initially, optimal operational conditions for each system utilized using water artificially turbid with Kaolin. For each system, samples were taken at 20-min interval after the system reached its optimal operational conditions. Parameters, such as turbidity, alkalinity, temperature, pH, and total suspended solids, were measured. For 20, 30–50 and 90–110 NTU, turbidity average removal efficiencies in DAF system were 14.7, 11.1 and 10.9%, respectively, larger than the conventional sedimentation system. The effect of coagulant dose indicated that DAF system with lower dosage of coagulant have higher removal efficiency. On the other hand, the results showed that due to increased efficiency of DAF system, solid concentration of sludge produced in this system was more than the sedimentation system (p \u3c 0.01). However, operation of DAF system needs accurate control devices and experienced technical staff to operate the system

Removal of turbidity from water by dissolved air flotation and conventional sedimentation systems using poly aluminum chloride as coagulant

Flotation is a method in which particles in liquid phase are transported to the surface by air bubbles. In this experimental study, a comparison has been made between conventional sedimentation and dissolved air flotation (DAF) systems to remove turbidity from water. Initially, optimal operational conditions for each system utilized using water artificially turbid with Kaolin. For each system, samples were taken at 20-min interval after the system reached its optimal operational conditions. Parameters, such as turbidity, alkalinity, temperature, pH, and total suspended solids, were measured. For 20, 30-50 and 90-110NTU, turbidity average removal efficiencies in DAF system were 14.7, 11.1 and 10.9, respectively, larger than the conventional sedimentation system. The effect of coagulant dose indicated that DAF system with lower dosage of coagulant have higher removal efficiency. On the other hand, the results showed that due to increased efficiency of DAF system, solid concentration of sludge produced in this system was more than the sedimentation system (p<0.01). However, operation of DAF system needs accurate control devices and experienced technical staff to operate the system

Water resource options for sustainable development in the Pilbara region of Western Australia

Water resources management in the Pilbara region of Western Australia is vital to industry, economy and the environment. This dissertation has aimed to develop a comprehensive hydrological and hydrogeological assessment of water resources in the Yandi mine area located in the Weeli Wolli Creek catchment in the Pilbara. Water resources in this area have become increasingly vulnerable due to growing demand. Climate conditions, geology and hydrogeology, streamflow and the groundwater system of the study area were assessed. Lumped, data-driven and numerical models were employed to develop an understanding of the available surface water and groundwater resources. Three equations were derived showing the rainfall-runoff relationship within Weeli Wolli Creek catchment and subsequent modelling was undertaken for more hydrology system evaluation. Artificial Neural Networks (ANNs) and IHACRES models were used to simulate the Marillana Creek streamflow discharge, upstream of Yandi. The results suggested that ANN models perform better for a complex catchment hydrological system, compared to IHACRES model. A VISUAL MODFLOW model was used to investigate the groundwater system and its trend in the Yandi area. The model helped to understand the groundwater responses to future development with various pumping strategies and climate conditions. The scenario analysis assisted identification of zones vulnerable to a significant decline in groundwater level in response to dewatering. The analysis indicated that the maximum water level drawdown of 25m occurred in the aquifer from maximum annual pumping of 23GL. With respect to groundwater yield in particular, abstraction has a more direct impact on the groundwater system compared to climate change. The recharge into the groundwater was estimated from the fluctuations of groundwater level, groundwater modelling and water balance method. The estimated recharge from these methods was comparable and consistent within 3 to 5% of rainfall. This suggests that direct rainfall infiltration is less, compared to localised infiltration. Two new equations, applicable to Australian conditions, were developed to estimate potential evapotranspiration (ET0). These equations form a part of the water balance equation for groundwater recharge estimation. An artificial intelligent model, based on the Honey-Bee Mating Optimization algorithm (HBMO), was introduced to calibrate the new ET0 equations. The newly developed equations had better performances than available popular equations. The results of this study showed that the water resources in Yandi are considerably affected by progressing activities and their associated water requirements. A combination of multiple water assessments and modellings suggested that it is feasible to predict future access to surface water as a function of its influencing factors such as climate condition and mining activities. Scenario analysis in groundwater assessment suggested possible alternative future dewatering strategies in the Yandi mine area. The possible groundwater level recovery time is estimated to be one hundred years, which indicates this resource may not be a reliable option in future. Hydrological water balance analysis also indicated that the available surface water volume would decrease to half upon cease of discharge due to closure of mines in the study area, which is controversial condition for future water management. This research can lead to the implementation of a sustainable water resources plan, and development of appropriate strategies

Glucose-induced cAMP elevation in β-cells involves amplification of constitutive and glucagon-activated GLP-1 receptor signalling

AIM: cAMP typically signals downstream of Gs -coupled receptors and regulates numerous cell functions. In β-cells, cAMP amplifies Ca2+ -triggered exocytosis of insulin granules. Glucose-induced insulin secretion is associated with Ca2+ - and metabolism-dependent increases of the sub-plasma-membrane cAMP concentration ([cAMP]pm ) in β-cells, but potential links to canonical receptor signalling are unclear. The aim of this study was to clarify the role of glucagon-like peptide-1 receptors (GLP1Rs) for glucose-induced cAMP signalling in β-cells. METHODS: Total internal reflection microscopy and fluorescent reporters were used to monitor changes in cAMP, Ca2+ and ATP concentrations as well as insulin secretion in MIN6 cells and mouse and human β-cells. Insulin release from mouse and human islets was also measured with ELISA. RESULTS: The GLP1R antagonist exendin-(9-39) (ex-9) prevented both GLP1- and glucagon-induced elevations of [cAMP]pm , consistent with GLP1Rs being involved in the action of glucagon. This conclusion was supported by lack of unspecific effects of the antagonist in a reporter cell-line. Ex-9 also suppressed IBMX- and glucose-induced [cAMP]pm elevations. Depolarization with K+ triggered Ca2+ -dependent [cAMP]pm elevation, an effect that was amplified by high glucose. Ex-9 inhibited both the Ca2+ and glucose-metabolism-dependent actions on [cAMP]pm . The drug remained effective after minimizing paracrine signalling by dispersing the islets and it reduced basal [cAMP]pm in a cell-line heterologously expressing GLP1Rs, indicating that there is constitutive GLP1R signalling. The ex-9-induced reduction of [cAMP]pm in glucose-stimulated β-cells was paralleled by suppression of insulin secretion. CONCLUSION: Agonist-independent and glucagon-stimulated GLP1R signalling in β-cells contributes to basal and glucose-induced cAMP production and insulin secretion

Glucose controls glucagon secretion by directly modulating cAMP in alpha cells

Aims/hypothesis Glucagon is critical for normal glucose homeostasis and aberrant secretion of the hormone aggravates dysregulated glucose control in diabetes. However, the mechanisms by which glucose controls glucagon secretion from pancreatic alpha cells remain elusive. The aim of this study was to investigate the role of the intracellular messenger cAMP in alpha-cell-intrinsic glucose regulation of glucagon release. Methods Subplasmalemmal cAMP and Ca2+ concentrations were recorded in isolated and islet-located alpha cells using fluorescent reporters and total internal reflection microscopy. Glucagon secretion from mouse islets was measured using ELISA. Results Glucose induced Ca2+-independent alterations of the subplasmalemmal cAMP concentration in alpha cells that correlated with changes in glucagon release. Glucose-lowering-induced stimulation of glucagon secretion thus corresponded to an elevation in cAMP that was independent of paracrine signalling from insulin or somatostatin. Imposed cAMP elevations stimulated glucagon secretion and abolished inhibition by glucose elevation, while protein kinase A inhibition mimicked glucose suppression of glucagon release. Conclusions/interpretation Glucose concentrations in the hypoglycaemic range control glucagon secretion by directly modulating the cAMP concentration in alpha cells independently of paracrine influences. These findings define a novel mechanism for glucose regulation of glucagon release that underlies recovery from hypoglycaemia and may be disturbed in diabetes