Atrazine,deethylatrazine, and deisopropylatrazine in surface runoff from conservation tilled watersheds

Atrazine and two of its metabolites, deethylatrazine (DEA) and deisopropylatrazine (DIA), are frequently detected in surface runoff. Although their health and environmental effects may be similar to that of atrazine and ratios of their concentrations are useful in delineating sources of contamination, there have been few long-term studies of the factors affecting their losses in runoff. Therefore, losses of atrazine, DEA, and DIA were monitored for six years in runoff from seven small (0.45-0.79 ha) watersheds under three tillage practices. Weather year and the timing of runoff-producing rainfall had a greater effect on atrazine, DEA, and DIA concentrations and losses than did tillage practice. DEA was the most frequently detected metabolite with an average concentration in the year of atrazine application, of 2.5 microg L(-1) compared to 0.7 microg L(-1) for DIA. Atrazine exceeded its 3 /g L(-1) maximum contaminant level (MCL) up to 100 days after application. DEA and DIA exceeded the atrazine MCL up to 50 days after atrazine application; thus, failure to monitor their presence may result in underestimation of the environmental impact of atrazine usage. The molar concentration ratio of DEA to atrazine (DAR) was affected by tillage treatment, weather year, and possibly soil type. These factors may need to be taken into account when DAR is used as an index of atrazine movement. The ratio of DIA to DEA (D2R) was fairly constant and should be useful in determining the parent compounds contributing DIA to surface waters.     

Quantitative and quality losses caused by rodents in on-farm stored maize: a case study in the low land tropical zone of Kenya

Rodents are one of the major storage pests in on-farm maize storage in the tropics. However, information on actual magnitude of weight and quality losses caused by rodents in maize stores and species of rodent associated with the losses is scarce and if available would help to improve maize postharvest management. Maize stores of small-scale farmers in the lowland tropical zone of Kenya were monitored for actual weight losses caused by rodents and rodent trapping was conducted to determine species and estimate population of the rodents associated with the losses. Moulds and total aflatoxin contamination and nutritional value of rodent-damaged grain and non-damaged grain samples were also compared to evaluate the impact of rodent infestation on grain quality. In a sample of 20 farmers, we found that cumulative weight losses due to rodents ranged from 2.2 to 6.9% in shelled maize grain and from 5.2 to 18.3% in dehusked cobs after storage for 3 months. Rattus rattus was the only rodent species captured over the whole trapping period with a trap success rate of 0.6–10.0%. Total mould count, Fusarium spp. incidence and total aflatoxin contamination were significantly higher in rodent-damaged grains than in the non-damaged ones whereas no significant differences were observed for the incidence of Aspergillus spp. There were also significant decreases in dry-matter, fat, crude protein and fatty acid content in rodent-damaged grain compared to non-damaged grain. These findings show that rodents are a significant cause of postharvest losses in on-farm maize storage and impact negatively on food nutrition and safety. Mitigation strategies for postharvest losses should therefore include rodent control.     

Susceptibility of varieties of stored rough rice to losses caused by storage insects

Losses caused by Sitophilus oryzae (L.), Rhyzopertha dominica (F.), and Sitotroga cerealella (Olivier) in 6 commercial varieties of rough rice from the Southern United States were assessed as weight loss of rough rice, loss of milling yield, and loss of monetary value. Over 3 insect generations, S. oryzae caused the least damage, probably because this species requires grains with gross hull defects and the proportion of such grains was relatively small. Damage attributable to S. cerealella or R. dominica was approximately equal. The varieties Vista and Lebonnet were the most susceptible and the variety Dawn the most resistant after 3 generations.     

Influence of slope angle and rainfall intensity on the runoff erosion control performance of woven geomesh

In this study, runoff erosion control performance of different coir and jute geomeshes is studied at different slope angle, rainfall intensity, and soil-infiltration conditions using a runoff erosion control tester (based on ASTM D 7101). It is observed that the erosion control percentage under soil-infiltration conditions is lower at higher slope angle and rainfall intensity, due to the higher water flow velocity, and because of the same reason runoff volume under zero-infiltration conditions is higher. It is also observed that the geomeshes with higher weight per unit area results in lower runoff and higher culmination, due to the higher storage volume and restriction offered by larger diameter weft yarn of higher weight geomesh.     

Low permeability triple-layer plastic bags prevent losses of maize caused by insects in rural on-farm stores

Participatory on-farm trials were conducted to assess effectiveness of Purdue Improved Crop Storage (PICS?) bags for storage of maize in small-scale farmers’ stores in rural villages in eastern Kenya. A PICS bag is a three-layered hermetic bag-system that forms a barrier against the influx of oxygen and the escape of carbon dioxide. Jute, woven polypropylene or PICS bags were filled with shelled maize grain, purchased from the participating farmers, and the three sets of bags kept in the farmers’ own stores for 35 weeks. Oxygen and carbon dioxide levels in the PICS bags were monitored, as well as the temperature and relative humidity in all the bags. Grain moisture, live insect population, grain damage and weight loss were examined at intervals of seven weeks. Oxygen and carbon dioxide composition demonstrated that PICS bags are capable of sustaining good air-barrier properties under farmer storage conditions. Moreover, moisture content of maize stored in PICS bags did not change throughout the storage period whereas the moisture content of maize stored in polypropylene and jute bags decreased significantly in the final 14 weeks. Maize stored in PICS bags remained free from insect infestation and the weight loss due to insect damage was below 1 %. On the contrary, polypropylene and jute bags permitted profuse build-up of insect populations. At 35 weeks, grain damage reached 77.6 % and 82.3 % corresponding to 41.2 % and 48.5 % weight loss in the polypropylene and jute bags respectively. These findings demonstrate that PICS bags are effective in controlling losses caused by storage pests under farmer storage conditions.     

Strategies to analyze milk losses caused by diseases with potential incidence throughout the lactation: a lameness example

The objective of this study was to test the hypothesis that lameness incidence in lactating dairy cows decreases milk production compared with controls and to determine the best method of the 5 combinations of 2 study designs (retrospective cohort and retrospective matched cohort) and 3 repeated measures statistical methods: ANOVA (with binary classification of lameness); ANOVA with a lameness index (LAMIX) as the variable of interest; and analysis of covariance (ANCOVA, controlling for mean milk production for the first 3 wk of lactation and with a binary classification of lameness). Data were from 1 dairy farm located near Ithaca, NY, and from cows that calved between January 1, 2004 and January 1, 2007. The LAMIX was defined as −1, −2, −3, −4, and −5 = 1, 2, 3, 4, and ≥5 mo before lameness was detected, respectively; 1, 2, 3, 4, and 5 = 1, 2, 3, 4, and 5 mo after diagnosis, respectively; and 0 = cows that were never lame. With the binary lameness classification analyzed by repeated measures ANOVA, there was no effect of lameness on milk yield. The model was biased because lame cows had higher milk yields before lameness compared with nonlame cows. When the LAMIX was used, milk production before lameness was greater than after lameness (3.1 ± 0.28 kg/d). Yet, point estimates generated for LAMIX were inaccurate because of the multicollinearity detected between LAMIX and week of lactation and because of the inability of adjusting the least squares means for the interaction of LAMIX and week of lactation. Therefore, the most appropriate models were the ANCOVA models (both for the matched and nonmatched retrospective-cohort designs). The estimated losses associated with lameness were 314 and 424 kg/cow per 305-d lactation, respectively, for the matched and nonmatched designs. Furthermore, high milk yield in the beginning of the lactation was a risk factor for lameness.     

Strength properties of Scots pine from harbour piles degraded by erosion bacteria

140-year-old Scots pine piles displaying various levels of degradation by erosion bacteria were excavated from the harbour of Hamburg and investigated. Bending and compression strength correlated to the basic density, moisture content and lignin content. The compression strength was determined both on samples with dimensions of 30 mm?×?20 mm?×?20 mm and using 6.6 mm-increment cores taken perpendicular to the grain direction. Both sizes of the samples showed almost identical results. The sapwood of all samples was completely water-saturated; the heartwood did not even achieve 50% water saturation. The sapwood samples showed a good correlation between moisture content and strength properties, whereas basic density correlated well with the strength properties of both sapwood and heartwood. With increasing bacterial attack and resulting lower basic density, the lignin content increased in relation to holocellulose. The measured lignin content of the sapwood showed a good conformity with all strength properties. Determination of the lignin content represents an alternative method for predicting strength values of waterlogged wood while leaving most of the test material intact.     

Electrical stimulation and ageing of carcasses from red,fallow and New Zealand wapiti-type male deer

Farmed male red deer (15 and 26 months), fallow deer (16 months) and New Zealand wapiti-type deer (26 months) slaughtered in an experimental abattoir were used to determine the influence of processing practices on tenderness and pH. Carcasses were electrically stimulated (low voltage) through the leg or anus immediately after bleeding and compared with non-stimulated carcasses. Portions of loin and leg from all carcasses were subjected to a range of conditioning and ageing treatments before tenderness assessment was done with a Warner-Bratzler shear press. Tenderness was measured in some samples after a freeze and slow thaw cycle. Electrical stimulation in all deer types had a highly significant effect in improving tenderness and the effects were most dramatic when carcasses were placed in a chiller 2 h after slaughter. Conditioning and ageing regimes (maximum 96 h post-slaughter) further improved tenderness, particularly in non-stimulated carcasses. Processing effects were more marked in loin pieces; these cooled more rapidly than leg. The process of freezing and slow thawing (20 h at 4°C in loins and 24–96 h at 0°C for legs) improved tenderness by 10–40% when compared with unfrozen pieces. There were highly significant reductions in the pH values of legs due to stimulation as measured during the early stages after slaughter. A decline in pH with time post-slaughter was also evident. The results were consistent with the post-slaughter pH profile of loins. Electrical stimulation, via either the leg or the anus, gave similar results. An exception was the loin pH measurement from anally stimulated wapiti stags which appeared higher than their leg-stimulated counterparts. Where data were collected from both sides of leg-stimulated carcasses, pH values were around 0.13 units lower for the stimulated shackled leg than for the free leg. Leg temperatures rose to over 40°C at 0.5 h post-slaughter in all deer. Temperatures were generally similar between stimulated and non-stimulated carcasses for both loin and leg data.     

Prediction of fluid losses from pork using subjective and objective paleness

Meat paleness in pork Longissimus dorsi (LD) 1 day post-mortem (p-m) was measured subjectively using Japanese Pork Colour Scores (JPCS) and objectively using a Colormet fibre-optic (FO) meat probe (400–700 nm). Water-holding capacity (WHC), fluid loss during thin-slicing, and drip loss were measured in unfrozen and in frozen and thawed (FT) samples. FT caused a decrease in WHC, and an increase in slicing and drip loss (P < 0·001). FO interactance (i) was correlated (P < 0·01) with unfrozen WHC (R = 0·55), with FT WHC (r = −0·45 at 440 nm), with FT slicing loss (R = 0·81), with unfrozen drip loss (R = 0·66), and with FT drip loss (R = 0·61). Objective measurements proved that the development of pork paleness takes several days p-m and that paleness is increased by FT. Where fluid losses were predictable from paleness, the FO probe was superior to subjective evaluation by JPCS.     

胶体金免疫层析试纸条快速检测水和玉米中阿特拉津的残留

本文以胶体金作为抗体标记物,建立了一种检测阿特拉津残留的免疫层析试纸条快速检测方法.该方法的检出限为2ng/mL,10min内可以得到检测结果.本文以自来水和玉米作为样品进行了添加回收实验,水样不需要任何前处理直接检测,水样的检出限为2 ng/mL;玉米样品经简单前处理后检测,玉米样品的检出限为40 ng/g,且该方法的检测结果与间接竞争ELISA方法的结果一致.该方法具有成本低、操作简单、灵敏度高、检测快速,结果易于判定等优点,适用于大量样品的现场筛选.     

Iridescence in beef caused by multilayer interference from sarcomere discs

Microscope photometry of raw and cooked iliocostalis was used to test the hypothesis that interference colours in beef may originate from reflections from sarcomere discs. Evidence in support of the hypothesis was, firstly, that interference colours were not altered by rotating a polarizer in the illumination pathway, or by rotating a polarizer in the measuring pathway. But when both pathways contained polarizers, iridescence was completely extinguished when the polarizers were crossed. Secondly, the reflectance spectra of interference colours all showed multiple interference peaks, with a major peak possibly originating from the top sarcomere and minor peaks originating from lower sarcomeres. Thirdly, major peaks were strongly dependent on the angle of measurement. Iridescence in beef is quite rare, but reflections from sarcomere discs may be a ubiquitous source of light scattering in meat.     

Synergistic effects of insect-resistant maize and Teretrius nigrescens on the reduction of grain losses caused by Prostephanus truncatus (Horn.)

Prostephanus truncatus is a pest that causes serious losses in stored maize (Zea mays L.) especially in developing countries. This research was conducted to investigate the use of post-harvest insect resistance maize in combination with biological control of P. truncatus by the predator Teretrius nigrescens to reduce maize storage losses. We studied the population dynamics of P. truncatus with and without a predator in combination with susceptible maize and resistant maize to insects under laboratory conditions. This study confirms that P84c3 is a resistant variety against P. truncatus. Maize resistant kernels had a reduction of 30% losses in comparison with susceptible kernels. Significant and favorable interactions were observed between P84c3 maize and presence of T. nigrescens. A dramatic reduction of 80% in progeny number, 81% grain weight loss, and 75% frass production caused by P. truncatus was observed when the predator was used in combination with P84c3. Resistant maize reduced the prey development time and consequently the insect density allowing the predator to control more effectively the population. Prey/predator proportion on resistant maize was significantly higher in comparison with susceptible kernels; thus, giving a more effective pest population control by the predator. These results demonstrated that the combination of post-harvest insect resistance maize with the predator T. nigrescens reduces grain maize losses by P. truncatus.     

Swimmer risk of gastrointestinal illness from exposure to tropical coastal waters impacted by terrestrial dry-weather runoff

This study used molecular methods to measure concentrations of four enteric viruses (adenovirus, enterovirus, norovirus GI, and norovirus GII) and fecal source tracking markers (human, ruminant, and pig Bacteroidales) in land-based runoff from 22 tropical streams on O'ahu, Hawai'i. Each stream was sampled twice in the morning and afternoon during dry weather. Viruses and human Bacteroidales were widespread in the streams. Watershed septic tank densities were positively associated with higher occurrence of human Bacteroidales and norovirus. There were no associations between occurrence of viruses and fecal indicator concentrations. Virus concentrations and previously reported culturable Salmonella and Campylobacter were used as inputs to a quantitative microbial risk assessment (QMRA) model to estimate the risk of acquiring gastrointestinal (GI) illness from swimming in tropical marine waters adjacent to discharging streams. Monte Carlo methods were used to incorporate uncertainties in the dilution of stream discharge with seawater, swimmer ingestion volumes, pathogen concentrations, and dose-response parameters into the model. Median GI illness risk to swimmers from exposure to coastal waters adjacent to the 22 streams ranged from 0 to 21/1000. GI illness risks from viral exposures were generally orders of magnitude greater than bacterial exposures. Swimming adjacent to streams positive for norovirus or adenovirus resulted in the highest risks. The median risk adjacent to each stream was positively, significantly correlated to the concentration of Clostridium perfringens in the stream. Although a number of important assumptions were made to complete the QMRA, results suggest land-based runoff in the tropics as a potential source of GI illness risk, with pathogens coming from both human and nonhuman nonpoint sources including septic tanks.     

Reducing gaseous losses of nitrogen from cattle slurry applied to grassland by the use of additives

Losses of nitrogen (N) through ammonia (NH₃) volatilisation and denitrification were determined following the application of cattle slurry to grassland in autumn or spring. Denitrification was examined on two contrasting soils. A system of small wind tunnels was used to measure NH₃ loss and an acetylene inhibition technique for denitrification. Between 31 and 84% of the ammonium N (NH-N) applied in slurry was lost through NH₃ volatilisation. Acidifying the slurry to pH c 5.5 prior to application reduced these losses to between 14 and 57%. On a freely drained loam soil, denitrification from unacidified slurry applied in the autumn at 80 m³ ha^?1 was continuous throughout the winter, with the maximum rate of 0.91 kg N ha^?1 day^?1 occurring a few weeks after slurry application. The total denitrification losses were equivalent to about 29% of the NH-N applied for this treatment and 41% for the acidified slurry. The nitrification inhibitor dicyandiamide reduced the amount of N lost through denitrification by 70% when applied with the slurry at 25 kg ha^?1, by 55% at 20 kg ha^?1 and by 30% at 15 kg ha^?1. The nitrification inhibitor nitrapyrin did not appreciably reduce denitrification. Denitrification losses were consistently small from slurry applied to the freely drained loam soil in spring, or to a poorly drained, silty clay in autumn or spring. Neither nitrification inhibitor was of benefit in these situations.     

Endogenous nitrogen losses in rats fed by intravenous and enteral routes

Endogenous losses of nitrogen were studied under the feeding with isocaloric mixtures containing glucose, polycose, mineral substances, and vitamins. At the end of the first week endogenous losses of nitrogen with urine and feces under both routes of feeding were higher than at the end of the second week of nitrogen-free feeding. Upon intravenous feeding the nitrogen-saving action of the mixture containing glucose was more remarkable at the end of the second week than that of the mixture containing glucose and fatty emulsion. Endogenous losses of nitrogen upon intravenous feeding with a mixture containing fatty emulsion and glucose and losses upon intragastric feeding with a mixture of fatty emulsion and polycose were similar at the end of the second week.     

Body protein losses estimated by nitrogen balance and potassium-40 counting

Body protein losses estimated from N balance were compared with those estimated by 40K counting. Six nonlactating dairy cows were fed an adequate N diet for 7 wk, a low N diet for 9 wk, and a replete N diet for 3 wk. The low N diet contained high cell wall grass hay plus ground corn, starch, and molasses. Soybean meal was added to the low N diet to increase N in the adequate N and replete N diets. Intake was measured daily. Digestibilities, N balance, and body composition (estimated by 40K counting) were determined during each dietary regimen. During low N treatment, hay dry matter intake declined 2 kg/d, and supplement increased about .5 kg/d. Dry matter digestibility was not altered by N treatment. Protein and acid detergent fiber digestibilities decreased from 40 and 36% during adequate N to 20 and 2%, respectively, during low N. Fecal and urinary N also declined when cows were fed the low N diet. By the end of repletion, total intake, fiber, and protein digestibilities as well as N partition were similar to or exceeded those during adequate N intake. Body protein (N) loss was estimated by N balance to be about 3 kg compared with 8 kg by 40K counting. Body fat losses (32 kg) were large because of low energy digestibility and intake. Seven kilograms of body fat were regained during repletion, but there was no change in body protein.     

几种辣椒酱对动物机体上火作用的研究

研究了几种辣椒酱中维生素B1、B2的含量,并通过动物实验测定了维生素含量与动物机体上火程度的关系.上海川湘生产的三种辣椒酱的维生素B1含量在7.053～12.167μg/g之间,维生素B2含量在21.300～33.783μg/g之间;对照样品中维生素B1的含量为3.000μg/g,维生素B2的含量为16.500μg/g.动物实验中灌喂三种川湘辣酱的实验组小白鼠的大便含水量较高于灌普通辣椒酱的实验组小白鼠,表明该辣酱比普通辣酱较不易使动物机体上火.