Mechanisms regulating inter‐annual variability in zooplankton advection over the Lofoten shelf,implications for cod larvae survival

Variability in the availability of suitable prey (mainly nauplii stages of Calanus spp.) in the early life stages of cod is likely a significant contributor to the fluctuations in the year‐class strength in the Arcto Norwegian cod stock. We have investigated the origin of the Lofoten shelf population of Calanus using a particle tracking model approach based on velocity fields simulated from 2002 to 2012. By performing backwards simulations of trajectories from particles released on the Lofoten shelf in early spring, we assessed the relative contribution of potential Calanus sources, such as the Lofoten Basin, the local overwintering on the continental shelf and the adjacent fjords. This analysis revealed significant interannual differences in advection patterns mainly driven by changes in wind conditions and variable strength of the Norwegian Coastal Current. Most of the particles advected into our study area originated on the shelf, and contrary to expectations, only a few originated from the Lofoten Basin where Calanus abundances tend to be high. These results suggest that contribution from the Lofoten Basin to the early spring shelf Calanus population may be overestimated and that contribution from more local sources, especially from adjacent fjords, may play a more important role than what has been previously anticipated. Our results highlight the necessity to improve quantification of shelf‐fjord exchange processes, as these may contribute more to the regulation of spring zooplankton stocks on the northern Norwegian shelf, and, as a result, may affect the survival of cod larvae in this area.     

Surface application of ammonium thiosulfate fertilizer to reduce volatilization of 1,3‐dichloropropene from soil

Atmospheric emission of the soil fumigant 1,3‐dichloropropene (1,3‐D) is of environmental concern because of its toxicity and carcinogenicity. Thiosulfate fertilizers have been found to rapidly transform 1,3‐D in soil to non‐volatile ions which are less toxic. We investigated the use of surface application of ammonium thiosulfate (ATS) for reducing 1,3‐D volatilization. In packed soil columns, emission of 1,3‐D applied by sub‐surface injection decreased with increasing ATS application rate and the amount of water used for delivering ATS. When ATS was applied in 9 mm water at 64 g m⁻², total 1,3‐D emission was reduced by 61%. The reduction was 89% when ATS was applied at 193 g m⁻². Bioassays showed that ATS application did not affect the effectiveness of 1,3‐D for controlling citrus nematodes. In field plots where a 1,3‐D emulsified formulation was applied via sub‐surface drip, surface spray of ATS reduced 1,3‐D emissions by 50%, and by 71% when the surface was also covered with polyethylene film. ATS application had no effect on the efficacy of root‐knot nematode control or tomato yields. These results suggest that surface application of thiosulfate fertilizers may be a feasible and effective strategy for minimizing 1,3‐D emissions. © 2000 Society of Chemical Industry     

Natural Removal of Crude and Heavy Fuel Oil on Rocky Shorelines in Arctic Climate Regimes

Water, Air, &; Soil Pollution - The ecotoxicity of nickel depends on water quality characteristics such as pH and dissolved organic carbon. Bioavailability models to predict nickel toxicity have...     

Reference interval and critical difference for canine serum fructosamine concentration

The purposes of the study were to obtain a reference interval and to calculate the critical difference between two analytical results for canine serum fructosamine concentration. To obtain a reference interval, the serum fructosamine concentration was measured in blood samples from 29 adult dogs after a 15-h fasting period. To calculate the critical difference, blood samples from 20 apparently clinically healthy dogs were collected once weekly for five consecutive weeks, and the total variance of the analytical results was divided into the component of variance between dogs (S _inter ² ), the component of variance for weeks within dogs (S _intra ² ) and the component of variance for measurements (S _anal ² ), using nested analysis of variance. The critical difference was then calculated fromS _intra ² andS _anal ² .The main conclusions are in summary: The reference interval for canine serum fructosamine concentration is 258.6–343.8 µmol/L, and the critical difference between two consecutive measurements on a week-to-week basis is 32.4 µmol/L. The critical difference may be used as a guideline to indicate potentially important changes in the serum fructosamine concentration, though the analytical results should not be assessed by the critical differences alone, but should also be compared to the corresponding reference intervals.     

Milking-Related Changes in the Surface Temperature of the Bovine Teat Skin

The surface temperature of the teat at rest is about 30°C in healthy dairy cows kept indoor under ordinary conditions. It usually decreases by about 1°C during manual premising teat stimulation (Hamann & Dück 1984, Eichel 1986, Hamann 1988,1992). And it usually increases above the level prior to the stimulation by up to about 2.5°C during the milk removal phase of conventional machine milking (Schneider 1981, Hamann & Dück 1984, Hamann 1985,1988,1989, Mayntz 1990, Eichel 1992). The statements made are supported by the results of our own investigations, i.e. − 0.8 and + 2.1 °C, respectively.     

Sorption, mineralization and mobility of N-(phosphonomethyl)glycine (glyphosate) in five different types of gravel

Sorption, mineralization and mobility of glyphosate were studied in six substrates: the five types of gravel most frequently used as surfacing in Denmark and a sandy agricultural soil from Simmelkaer that served as a reference soil. Cumulative mineralization of [methyl-14C]glyphosate in batch studies was highest in coarse gravel, amounting to 14% after 4 days at 30 degrees C and 32% after 31 days. Mineralization was slowest in the sandy reference soil, amounting to only 2% after 31 days. The adsorption coefficient (Kd) of glyphosate in gravel ranged from 62 to 164 litre kg(-1), while that in the sandy reference soil was 410 litre kg(-1). The results indicate that the relatively low Kd in gravel allows a relatively high rate of glyphosate mineralization by the biomass. When Kd is high, in contrast, mineralization is slow. Lowering the temperature to 10 degrees C decreased mineralization by 50% in one of two gravels. The leaching of glyphosate was screened in simple columns of gravel or soil in which precipitation events (20 mm over a 2-h period) were simulated on three occasions, starting either immediately after or 2 days after application of glyphosate. [14C]Glyphosate was applied as a tracer mixed with the commercial product Roundup Garden at the recommended rate of 2.4 kg glyphosate ha(-1), equivalent to 1 microg g(-1) soil. The highest concentration of [14C] compounds (expressed in terms of glyphosate concentration) in leachate from the columns exceeded 1300 microg litre(-1), and was detected in rounded gravel after the first rain event. No glyphosate was detected in leachate from the sandy reference soil.     

Effect of romifidine on the nociceptive withdrawal reflex and temporal summation in conscious horses

OBJECTIVE: To investigate the action of a single IV administration of romifidine on the thresholds of the nociceptive withdrawal reflex (NWR) and temporal summation in conscious horses. ANIMALS: 10 adult horses. PROCEDURE: Single electrical stimulations were applied on the digital nerves to evoke NWR from the left forelimb and hind limb. Repeated electrical stimulations (10 stimuli, 5 Hz) were given to obtain temporal summation. Surface electromyographic reflex activity was recorded from the common digital extensor and cranial tibial muscles. After baseline assessment of NWR and temporal summation thresholds, romifidine (80 microg x kg(-1), IV) was administered. Successive determinations of NWR and temporal summation thresholds were performed 5, 25, and 55 minutes after administration. RESULTS: Romifidine significantly increased the current intensities necessary to evoke NWR and temporal summation in forelimbs and hind limbs of horses. Values were significantly higher than baseline values 55 minutes after romifidine administration. After administration of romifidine, a facilitation of reflex components of tactile origin was observed when repeated stimulations were applied. CONCLUSIONS AND CLINICAL RELEVANCE: Results confirm antinociceptive activity of romifidine and may represent an objective demonstration of the well-known hypersensitivity to tactile stimuli observed in horses receiving alpha2-adrenoreceptor agonists in clinical practice. Romifidine can be included in analgesic and anesthetic protocols to provide additional analgesia in horses.     

Production and spatial price differences for charcoal in Uganda

Charcoal production activity assumes importance not only for generating large employment and income and supplying major fuel requirements in Uganda but also for triggering environmental degradation. Based on production and marketing data collected from one of the important charcoal producing districts, namely, Nakasongola, this study found that charcoal production being less capital intensive and risk free, is mainly carried out by numerous small, economically weak and unorganised individual producers. The price-distance relationship was analysed for the average prices of a bag of charcoal prevalent in each town over a stretch of 140 km between Kampala, the capital and main consuming center for charcoal in Uganda, and Kafu Bridge during the years 1995 and 1999. A movement of 1 km from Kampala resulted in a price decline of about 28 UShs in 1995 and 33 UShs in 1999 (prices held constant at 1995 level). The price-distance relationship and responsiveness of charcoal prices to distance from Kampala, as measured through distance elasticity of price, remained unchanged over the period 1995 to 1999. There is no statistical evidence to prove that the charcoal producers were better paid in 1999 than in 1995. It appears unlikely to halt the harmful environmental degradation effects of charcoal making activity without generating adequate alternate employment opportunities in rural areas and internalizing the full environmental costs of forest degradation in the consumer price of charcoal.     

Contribution of fallow periods between rice crops to seasonal GHG emissions: effect of water and tillage management

ABSTRACT

Irrigated rice cultivation is a major source of greenhouse gas (GHG) emissions from agriculture. Methane (CH₄) and nitrous oxide (N₂O) are emitted not only throughout the growing season but also in the fallow period between crops. A study was conducted for two transition periods between rice crops (dry to wet season transition and wet to dry season transition) in the Philippines to investigate the effect of water and tillage management on CH₄ and N₂O emissions as well as on soil nitrate and ammonium. Management treatments between rice crops included (1) continuous flooding (F), (2) soil drying (D), (3) soil drying with aerobic tillage (D + T), and (4) soil drying and wetting (D + W). The static closed chamber method was used to measure CH₄ and N₂O fluxes.

Soil nitrate accumulated and N₂O was emitted in treatments with soil drying. Nitrate disappeared while ammonium gradually increased after the soil was flooded during land preparation, indicating net nitrogen mineralization. N₂O emissions were highest in both transition periods in D + W (437 and 645 µg N₂O m^?2 h^?1). Methane emissions were significant in only the F treatment. The highest global warming potential (GWP) in the transition between rice crops occurred in F, with CH₄ contributing almost 100% to the GWP. The GWP from other treatments was lower than F, with about 60–99% of the GWP attributed to N₂O emissions in treatments with soil drying. The GWP in the transition between rice crops represented up to 26% of the total GWP from harvest to harvest. This study demonstrates that the transition period can be an important source of GHG emissions with relative importance of CH₄ and N₂O depending on the soil water regime. Therefore, the transition period should not be disregarded when estimating GHG emissions for rice cropping systems.     

Hammerstein-Wiener model for the prediction of temperature variations inside silage stack-bales using wireless sensor networks

Animal forage plays an important role in agriculture. To maintain the silage quality during storage, preserving it from decomposition by wrapping the harvested crop with plastic stretch film is crucial. Any failure in the preserving process permits the infusion of oxygen, which allows the growth of undesirable aerobic microorganisms and silage decomposition. To study the state of the silage, temperature inside the stack could be used as indicator of decomposition. However, no previous study has developed a model that can detect decomposition based on abnormal temperature variations inside a silage stack. The first objective of this paper was to develop a structured nonlinear model to estimate the dynamics of temperature variations measured by a wireless sensor network-based monitoring system (nRF95E) inside a silage bale and stack prior to the decomposition process. The requirement of a robust nonlinear model is that sensor nonlinearities that are inherent in nature are considered. The results showed that a Hammerstein-Wiener (HW) model with sigmoid network performed the best in terms of percentage of fit (91.70%) between the measured and simulated output. The second objective was to estimate the length of time required to detect the decomposition process after the airtight seal was punctured using the model. The error between the predicted model output and the sensor readings exceeded a preset threshold interval 17 days after the cover film was punctured and 9 days after the decomposition process was detected due to the odour released.