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Maximum Limit (maximum + limit)
Selected AbstractsMaximum limits of organic and inorganic mercury in fish feedAQUACULTURE NUTRITION, Issue 2 2004M.H.G. Berntssen Abstract The relatively high levels of mercury found in fish feeds might form a fish health and food safety risk. The present study aims to establish sublethal toxic threshold levels in fish and assess feed-fillet transfer of dietary mercury. Atlantic salmon (Salmo salar L.) parr were fed for 4 months on fish meal-based diets supplemented with mercuric chloride (0, 0.1, 1, 10 or 100 mg Hg kg,1 dry weight (DW)) or methylmercuric chloride (0, 0.1, 0.5, 5 or 10 mg MeHg kg,1 DW). At the end of the experiment, dietary inorganic mercury mainly accumulated in intestine (80% of body burden) and assimilation was low (6%). In contrast, methylmercury readily accumulated in internal organs and muscle (80% of body burden) and had a relatively high assimilation (23%). Highest accumulation of dietary inorganic mercury was observed in the gut and kidney. Fish fed 10 mg Hg kg,1 had an early (after 2 months) significant increase in renal metallothionein (MT) level and intestinal cell proliferation, followed by intestinal pathological conditions after 4 months of exposure. At 100 mg Hg kg,1, intestinal and renal function were reduced as seen from the significantly reduced protein and glycogen digestibility and increased plasma creatinine levels. For dietary methylmercury (MeHg), highest accumulation was found in blood and muscle. Intestinal cell proliferation and liver MT significantly increased at 5 mg MeHg kg,1 after 2 months of exposure. At the end of the experiment, blood haematology was significantly affected in fish fed 5 mg MeHg kg,1 and these fish exceeded the current food safety limit for mercury. Tissue MT induction and intestinal cell proliferation appeared to be useful and quantifiable early indicators of toxic mercury exposures. Based on the absence of induction of these early biological markers such as MT and cell proliferation, nonobserved effect levels (NOELs) could be set to 0.5 mg Hg kg,1 for dietary methylmercury and 1 mg Hg kg,1 for inorganic mercury. Lowest observed effect levels (LOELs) levels could be set to 5 mg kg,1 for methylmercury and 10 mg Hg kg,1 for inorganic mercury. [source] Utilization of a Copper Solid Amalgam Electrode for the Analytical Determination of AtrazineELECTROANALYSIS, Issue 22 2005Djenaine De, Souza Abstract A copper solid amalgam electrode was prepared and used for the voltammetric determination of atrazine in natural water samples by square wave voltammetry. This electrode is a convenient substitute for the hanging mercury electrode since it is selective, sensitive, reliable and inexpensive and presents low toxicity characteristic. The detection limit of atrazine obtained in pure water (laboratory samples) was shown to be lower than the maximum limit of residue established for natural water by the Brazilian Environmental Agency. The relative standard deviation for 10 different measurements was found to be only 3.98% in solutions containing 8.16×10,6,mol L,1 of atrazine. In polluted stream water samples, the recovery measurements were approximately 70.00%, sustaining the applicability of the proposed methodology to the analysis of atrazine in such matrices. [source] The one-warehouse multiretailer problem with an order-up-to level inventory policyNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 7 2010uz Solyal Abstract We consider a two-level system in which a warehouse manages the inventories of multiple retailers. Each retailer employs an order-up-to level inventory policy over T periods and faces an external demand which is dynamic and known. A retailer's inventory should be raised to its maximum limit when replenished. The problem is to jointly decide on replenishment times and quantities of warehouse and retailers so as to minimize the total costs in the system. Unlike the case in the single level lot-sizing problem, we cannot assume that the initial inventory will be zero without loss of generality. We propose a strong mixed integer program formulation for the problem with zero and nonzero initial inventories at the warehouse. The strong formulation for the zero initial inventory case has only T binary variables and represents the convex hull of the feasible region of the problem when there is only one retailer. Computational results with a state-of-the art solver reveal that our formulations are very effective in solving large-size instances to optimality. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010 [source] Antimicrobial efficiency and sorbic acid migration from active films into pastry doughPACKAGING TECHNOLOGY AND SCIENCE, Issue 4 2007M. F. A. Silveira Abstract Antimicrobial films of 25 and 70¯m thickness, incorporated with 7 and 3% sorbic acid, respectively, were layered with pastry dough without additive and evaluated for sorbic acid migration and antimicrobial efficiency. Pastry dough containing potassium sorbate layered with low-density polyethylene films (LDPE) was used as a control. The films/pastry sandwiches were stored in LDPE bags at 8 ± 1°C. After 40 days of storage, the dough layered with 25¯m/7% films showed a reduction of 2log cycles in the aerobic mesophilic count; however, there were no significant differences (p , 0.05) for the psychotropic and Staphylococcus spp. counts. For the dough layered with 70¯m/3% films there were reductions of 2 and 1.5log cycles in the mesophilic and psychotropic counts, respectively. In the control dough, the aerobic mesophilic, psychotropic and Staphylococcus spp. counts increased by 1.5, 1 and 2log cycles, respectively. Regardless of the film, the counts of filamentous fungi, yeasts and coagulase-positive staphylococcus were <1.0 ¥ 102CFU/g, whereas the coliform counts at 35 and 45°C, and Escherichia coli were <3.0 ¥ 100NMP/g. The diffusion coefficients of the sorbic acid from the films into the dough had values in the order of 10 -18m2/s. There were no differences (p , 0.05) between migration values among the films. The maximum additive release from the 25¯m/7% film into the dough after 20 days was 0.07%, and from the 70¯m/3% film after 9 days was 0.09%. Both values are below the maximum limit allowed by current legislation. Copyright © 2007 John Wiley & Sons, Ltd. [source] Tolerance of Atlantic salmon (Salmo salar) to dietborne endosulfan assessed by haematology, biochemistry, histology and growthAQUACULTURE NUTRITION, Issue 5 2010A.-K. LUNDEBYE Abstract The inclusion of plant-based ingredients in commercial fish feeds may pose a challenge because of the presence of undesirable substances, such as the pesticide endosulfan. Waterborne endosulfan is highly toxic to fish, whereas dietborne exposure has varied toxicity in different species. To investigate the systemic effects of endosulfan exposure, quadruplicate groups of Atlantic salmon (Salmo salar) were fed either 0 (control), 0.005 mg kg,1; the European Union's maximum limit, or 10 or 20 times this level (0.05 and 0.1 mg kg,1 respectively) for 95 days. There were no significant differences (P > 0.05) in liver somatic index, spleen somatic index, condition factor or growth among treatments. There were no indications of liver damage in fish from any of the groups in the biomarkers measured: plasma aspartate aminotransferase, plasma alanine aminotransferase and histopathology. Similarly, there were no apparent treatment-related effects on the haematological parameters Hct, Hb, mean corpuscular volume, mean corpuscular haemoglobin concentration and mean corpuscular haemoglobin, and blood sodium, potassium, calcium and chloride levels were not significantly (P > 0.05) different among groups. Lipid digestibility, but not energy, protein, or glycogen digestibility, was significantly (P < 0.05) reduced at the highest exposure concentration. However, no significant differences were observed in lipid production value or lipid efficiency ratio. In contrast to previous studies, clinical histological abnormalities were not observed in the intestine, liver or spleen of endosulfan-treated fish. [source] Late Weichselian glacial history and postglacial emergence of Phippsøya, Sjuøyane, northern Svalbard: a comparison of modelled and empirical estimates of a glacial-rebound hinge lineBOREAS, Issue 1 2000STEVEN L. FORMAN Field research on Phippsøya, the largest island in the Sjuøyane archipelago, defines the course and timing of postglacial emergence, documents past-glacier movements, and reinterprets deglacial sedimentary sequences. Previously described tills were not identified in sections exposed along the northeast shore of Phippsøya, but instead sublittoral sediments with rock-fall concentrations derived from the adjacent slope. A glacio-isostatically higher sea level >40 ka deposited sublittoral sediment and is possibly correlative to a deglacial event in oxygen isotope stage 4 or 5 identified at other sites on Svalbard. The postglacial marine limit is 22 ± 1 m aht and occurs as an escarpment or washing limit into a stony drift. This drift contains granite and quartzite erratics from Nordaustlandet that indicate coverage by a northward flowing ice sheet during the Late Weichselian. Datable material on the raised-beach sequence was rare and a 14C age of c. 9.2 ka on an articulated Balanus balanus from 10 m aht provides a minimum constraining age on the marine limit. A mild transgression occurred by 6.2 ka, with sea level falling close to present levels by c. 5.0 ka. The zone of zero emergence (hinge line) lies 10 to 20 km north of Sjuøyane and is approximately coincident with the last glacial maximum limit on the continental shelf. There is an approximately 75 to 100 km offset between observed and modelled zone of zero emergence, indicating a need to refine earth rheology-based ice-sheet models. [source] The bacterial quality of red meat and offal in Casablanca (Morocco)MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 6 2006Nozha Cohen Abstract The present study aimed to evaluate the bacteriological quality of beef (n = 52), lamb (n = 52) and beef offal (n = 52) marketed in Casablanca, Morocco. Meat and offal samples (n = 156), were collected randomly from butcheries, supermarkets, and slaughterhouses. Two sampling periods were considered, one during the hot season and the second one during the cold season. The samples were analyzed for the presence of the following bacteria: Escherichia coli, coagulase-positive Staphylococcus, Clostridium perfringens, Salmonella, and Listeria monocytogenes. Results indicated that counts of the aerobic plate count, and fecal coliforms were particularly high in all the samples analyzed. E. coli, coagulase-positive Staphylococcus and C. perfringens were detected in 37.8, 16, and 4.5% of the meat samples, respectively. Neither Salmonella nor L. monocytogenes were isolated from meat samples. Approximately 26.9% of beef, 34.6% of lamb and 28.8% of beef offal samples contained bacteria above the maximum limits established by the Moroccan regulatory standards for meat and meat products. Seasonality and the distribution location significantly (p < 0.05) affected bacterial populations: the hot season and butcheries appeared to be cases where the highest populations of bacteria in meat were observed. These high levels of microbiological contamination attest the poor hygienic quality of meat and offal, possibly due to uncontrolled processing, storage, and handling of these products. [source] Path optimization for the resource-constrained searcher,NAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 5 2010Hiroyuki Sato Abstract We formulate and solve a discrete-time path-optimization problem where a single searcher, operating in a discretized three-dimensional airspace, looks for a moving target in a finite set of cells. The searcher is constrained by maximum limits on the consumption of one or more resources such as time, fuel, and risk along any path. We develop a specialized branch-and-bound algorithm for this problem that uses several network reduction procedures as well as a new bounding technique based on Lagrangian relaxation and network expansion. The resulting algorithm outperforms a state-of-the-art algorithm for solving time-constrained problems and also is the first algorithm to solve multi-constrained problems. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010 [source] | ||||||||||