Second Set Of Trials Research Articles

Energy saving potential of interstage screen fractionation for production of board grade BCTMP

Over the last few decades, the continuing decline in mechanical pulp-based grades has led pulp producers to modify operations and implement measures to reduce production costs in order to stay competitive. In spite of a considerable effort to reduce energy consumption, the latter is still a major portion of production costs in the process of making bleached chemithermomechanical pulp (BCTMP). In this study, we evaluated the impact of interstage screening fractionation (ISSF) and secondary refining strategy for producing BCTMP with the objective of reducing refining energy consumption while maintaining or improving bulk and strength properties. In the first step and to establish a baseline for a mill’s existing configuration, the collected primary refined pulp and reject streams from the ISSF were refined in a high consistency (HC) refiner to target freeness levels. The accepts and refined rejects streams were recombined, and their properties were compared to those of the refined primary pulp. The results showed that, at a given freeness of 400 mL and compared to the control case (without fractionation), the ISSF using an 0.070 in. basket followed by rejects refining could lead to about 25% energy saving in the second stage HC refining. Handsheet properties showed that utilization of ISSF could produce BCTMP with higher bulk and similar average fiber length and tear index. However, a slight reduction in tensile strength was observed. In the second set of trials, the primary refined pulp and the rejects from the ISSF using the 0.070 in. basket were refined by a low-consistency (LC) refiner. The results showed that, at the same freeness of 400 mL and compared to refined primary pulp, the ISSF saved about 26% in net LC refining energy. At a specific edge load (SEL) of 0.4 J/m, the produced pulp had similar bulk and strength properties compared to those of the control sample. A higher SEL of 0.6 J/m in LC refining could further decrease net refining energy consumption; however, it also led to reduction in fiber length, bulk, and strength properties.

Shedding Light on Races of the Spinach Fusarium Wilt Pathogen, Fusarium oxysporum f. sp. spinaciae.

Two pathogenicity groups of Fusarium oxysporum f. sp. spinaciae, the causal agent of Fusarium wilt of spinach (Spinacia oleracea), were described recently based on virulence of isolates on proprietary spinach inbreds. In this study, a wide range in severity of wilt was observed for 68 spinach cultivars inoculated with an isolate of each pathogenicity group, with 22 (32.4%) cultivars displaying differential responses to the isolates. In a second set of trials, seven spinach cultivars were inoculated with five isolates of each pathogenicity group. The cultivars had similar wilt responses to isolates within each group. In both sets of trials, the most severe wilt developed on cultivars inoculated with pathogenicity group 2 isolates when daylength was shorter and light intensity lower. To test whether light intensity exacerbates severity of Fusarium wilt, three spinach cultivars were inoculated with two isolates of each pathogenicity group and grown with or without shading. Shaded plants developed more severe wilt than nonshaded plants. This difference in wilt severity was greatest for plants inoculated with pathogenicity group 2 isolates. We propose naming isolates of pathogenicity groups 1 and 2 as races 1 and 2 of F. oxysporum f. sp. spinaciae, respectively, and recommend the cultivars Kiowa (susceptible to both races) and Magnetic (susceptible to race 2 and highly resistant to race 1) as differentials. Results of this study should help breeders screen spinach germplasm for resistance to both races of F. oxysporum f. sp. spinaciae.

Male mate choice in mosquitofish: personality outweighs body size

BackgroundDespite its important implications in behavioural and evolutionary ecology, male mate choice has been poorly studied, and the relative contribution of personality and morphological traits remains largely unknown. We used standard two-choice mating trials to explore whether two personality traits (i.e., shyness and activity) and/or body size of both sexes affect mate choice in male mosquitofish Gambusia affinis. In the first set of trials involving 40 males, we tested whether males would prefer larger females and whether the preference would be affected by males’ body length and personality traits, and females’ activity level. In the second set of trials (using another 40 males), we tested whether males would prefer more active females and whether the preference would be affected by males’ body length and personality traits.ResultsBoth shyness and activity in males were significantly repeatable and constituted a behavioural syndrome. No overall directional preference for large (or small) females with the same activity levels was detected because larger males preferred larger females and smaller males chose smaller females. Males’ strength of preference for larger females was also positively correlated with the activity level of larger females but negatively with the activity level of smaller females. Males spent more time associating with active females regardless of their body lengths, indicating males’ selection was more influenced by female activity level than body size. Males’ preference for inactive females was enhanced when females became active. There was no convincing evidence for the effect of males’ personality traits or body length on their preferences for females’ activity level.ConclusionsOur study supports the importance of body size in male mate choice but highlights that personality traits may outweigh body size preferences when males choose mating partners.

Acceptability of Bedding Plants by the Leatherleaf Slug, Leidyula floridana (Mollusca: Gastropoda: Veronicellidae)

Leidyula floridana (Leidy) (Gastropoda: Veronicellidae) has long been known to be a plant pest in the Caribbean region and southern Florida, though its range has expanded to include northern Florida, other Gulf Coast states, and Mexico. It is nocturnal, and often overlooked as a source of plant damage. Although polyphagous, it does not feed on all plants, and it is desirable to know what bedding plants will likely be damaged by this common herbivorous slug. To identify readily accepted bedding plants, I conducted a series of comparative trials of 7 d duration to assess the acceptance of 30 commonly grown bedding plants relative to French marigold, a plant that is commonly fed upon by slugs and snails. Several commonly grown bedding plants were shown to be very susceptible to feeding injury. In a second set of 7-d trials, I compared 14 plants from among those that were not readily accepted in the first set of trials to determine if they would remain poorly accepted when not provided with favored food. In the second set of trials, the levels of herbivory shown in the first trials were maintained, demonstrating that some bedding plants are not acceptable to L. floridana even when the slugs do not have access to acceptable food. Thus, a list of readily available bedding plants that resist herbivory by this slug has been determined, providing gardeners with slug-resistant choices. The most unacceptable species (damage rating = 1.00) were: lantana (Lantana camara L.; Verbenaceae), tickseed (Coreopsis spp.; Asteraceae), torenia (Torenia fournieri Linden ex E. Fourn.; Linderiaceae), angelonia (Angelonia angustifolia Benth.; Plantaginaceae), and snapdragon (Antirrhinum majus L.; Plantaginaceae). Additional plant species that were not very acceptable (damage rating of between 1.00 and 1.50) were blue daze (Evolvulus glomeratus Choisy; Convolvulaceae), dusty miller (Centaurea cineraria [L.] Jacq. ex Nym.; Asteraceae), viola (Viola hybrid; Violaceae), celosia (Celosia argentea L.; Amaranthaceae), and geranium (Geranium spp.; Geraniaceae). In contrast, plant species that seem to be at considerable risk of damage (damage rating 3 to 5) by L. floridana were: French marigold (Tagetes patula L.; Asteraceae), Madagascar periwinkle (Catharanthus roseus [L.] G. Don; Apocyanaceae), coleus (Plectranthus scutellarioides [L.] R. Br.; Laminaceae), petchoa (Petunia × Calibrachoa; Solanaceae), zinnia (Zinnia elegans Jacq.; Asteraceae), polka dot plant (Hypoestes phyllostachya Baker; Acanthaceae), chrysanthemum (Chrysanthemum morifolium Ramat; Solanaceae), petunia (Petunia spp.; Solanaceae), Stokes' aster (Stokesia laevis [Hill] Greene; Asteraceae), scarlet sage (Salvia splendens Sellow ex Nees; Lamiaceae), butter daisy (Melampodium paludosum Kunth; Asteraceae) and verbena (Verbena spp.; Geraniaceae). A few species were intermediate in susceptibility, namely: impatiens (Impatiens hawkeri W. Bull; Balsamaniaceae), wax begonia (Begonia × Semperflorens × Cultorum; Begoniaceae), sweet potato vine (Ipomoea spp.; Convolvulaceae), firecracker flower (Crossandra infundibuliformis [L.] Nees; Acanthceae), sweet William (Dianthus barbatus L.; Caryophyllaceae), pansy (Viola × Wittrochinana; Violaceae), purslane (Portulaca oleraceae L.; Portulacaceae), and alyssum (Lobularia maritima [L.] Desv.; Brasscaeae).

Effect of biocontrol agents and potassium phosphite against Phytophthora crown rot, caused by Phytophthora capsici, on zucchini in a closed soilless system

Five biocontrol agents and potassium phosphite, used at various concentrations and at a different number of applications, have been tested to establish their ability to control Phytophthora capsici on hydroponically grown zucchini plants. In a first set of trials, various experimental biocontrol agents (Trichoderma sp. TW2, a mixture of Pseudomonas FC7B, FC8B, FC9B, Fusarium solani FUS25 and Pseudomonas sp. PB26) and a commercial formulation of Trichoderma gamsii +T. asperellum (Remedier) were applied at the artificial infestation with the pathogen of a peat substrate, 5–7 days before planting the zucchini seedlings, and later at 5-day-intervals. BCAs were compared with a potassium phosphite-based fertiliser. In a second set of trials, the potassium phosphite fertiliser was applied directly to the growing media or via a nutrient solution every 6 days, starting at the infestation with the pathogen and 5–7 days before planting, in order to select the optimal rate, type and number of applications. Potassium phosphite reduced Phytophthora crown rot of zucchini by 62–94%, providing more consistant disease severity reduction than those achieved using the experimental BCAs, alone or in mixture, and the Trichoderma gamsii + T. apserellum formulated mixture (29–47% reduction in disease severity). One application of potassium phosphite, at the highest tested concentration, was less effective than three applications. Potassium phosphite consistently reduced the severity of Phytophthora crown rot under different disease pressure (by 48–79%) when applied via a treated peat growing media or via a nutrient solution with 3–6 applications, thereby offering growers an important opportunity to control P. capsici on soilless grown zucchini.

Chance or choice? Understanding parasite selection and infection in multi-host communities

Ongoing debate over the relationship between biodiversity and disease risk underscores the need to develop a more mechanistic understanding of how changes in host community composition influence parasite transmission, particularly in complex communities with multiple hosts. A key challenge involves determining how motile parasites select among potential hosts and the degree to which this process shifts with community composition. Focusing on interactions between larval amphibians and the pathogenic trematode Ribeiroia ondatrae, we designed a novel, large-volume set of choice chambers to assess how the selectivity of free-swimming infectious parasites varied among five host species and in response to changes in assemblage composition (four different permutations). In a second set of trials, cercariae were allowed to contact and infect hosts, allowing comparison of host-parasite encounter rates (parasite choice) with infection outcomes (successful infections). Cercariae exhibited consistent preferences for specific host species that were independent of the community context; large-bodied amphibians, such as larval bullfrogs (Rana catesbeiana), exhibited the highest level of parasite attraction. However, because host attractiveness was decoupled from susceptibility to infection, assemblage composition sharply affected both per-host infection as well as total infection (summed among co-occurring hosts). Species such as the non-native R. catesbeiana functioned as epidemiological ‘sinks’ or dilution hosts, attracting a disproportionate fraction of parasites relative to the number that established successfully, whereas Taricha granulosa and especially Pseudacris regilla supported comparatively more metacercariae relative to cercariae selection. These findings provide a framework for integrating information on parasite preference in combination with more traditional factors such as host competence and density to forecast how changes within complex communities will affect parasite transmission.

EFFECTIVENESS OF SPINOSAD AND MINERAL OIL BASED COMMERCIAL PRODUCTS ON OVIPOSITION AND EGG HATCHING OF GRAPHOLITA FUNEBRANA TREITSCHKE

Laboratory trials were performed to evaluate the actionof spinosad and mineral oil on eggs of GrapholitafunebranaTreitschke, the key pest in plum orchards. Fruits of cultivars Angeleno, President and Stanley were used in thetrials. The first set of tests was carried out by introducing two mated females of G. funebranainto a cage together withfruits of a single cultivar. The second set of trials tested the three cultivars simultaneously. In all trials, one third of thefruits of each cultivar was treated with mineral oil, another third with spinosad and the final third was left untreated.Treatments were carried out before introducing mated females into the cages. The number of fruits with eggs, the numberof eggs laid on each fruit and the number of hatched eggs were recorded. The number of eggs per fruit recorded in all trialswas the same, indicating that plum moth females, after choosing the fruits for oviposition on the basis of the cultivar or theapplied product, tend to use all suitable fruits in the same way. Oviposition in terms of number of fruits was significantlylower in mineral oil and spinosad treatments in all trials, compared to the control. Differences between the two productswere found in trials carried out with Angeleno alone and with the three cultivars together. The percentage of egg hatchingon the fruits was always significantly lower with spinosad treatment compared to the mineral-oil treatment and the control.In the trials carried out using the three cultivars, the number of infested fruits was significantly higher for Angeleno and nodifferences in the hatching percentages were found among the cultivars. The ovicidal and antiovideponent activities ofcommercial products containing mineral oils orspinosad could represent an interesting tool to reduce G. funebranadamage, both in organic and conventional plum orchards.

Rapid large-volume concentration for increased detection of Escherichia coli O157:H7 and Listeria monocytogenes in lettuce wash water generated at commercial facilities

In pilot-scale testing, dead-end ultrafiltration concentration (DEUF-C) sampling increased detection of pathogens in lettuce wash water. This study investigated DEUF-C performance when scaled up to commercial processing levels. Two sets of experiments were done to: 1) compare pathogen detection probability in lettuce wash water generated from commercial pilot-scale processing using DEUF-C versus standard grab sampling, and 2) evaluate DEUF-C to concentrate pathogens inoculated into commercially-generated flume and centrifuge lettuce wash water. In pilot-scale runs, one lettuce head inoculated to contain 2–8 × 104 CFU of Escherichia coli O157:H7 and 3–10 × 105 CFU of Listeria monocytogenes was processed along with 907 kg of uninoculated lettuce using sanitizer-free tap water. Two to four 40-L volumes of the wash water were concentrated to 400 mL by DEUF-C, and pathogen detection probability in these samples was compared to standard grab samples after 24 h–48 h of enrichment using qPCR. In the second set of trials, chlorine in flume and centrifuge water from a local commercial processing facility was neutralized with sodium thiosulfate (100 mg/L), spiked with both E. coli O157:H7 and L. monocytogenes at 102 CFU/mL, and processed by DEUF-C. Total filterable volume was determined for DEUF-C samples, and detection (qPCR) probabilities in unenriched DEUF-C and grab samples were determined. E. coli O157:H7 and L. monocytogenes were detected in 100% of the DEUF-C samples from pilot-scale water samples. Comparable grab samples yielded 6.7% detection for E. coli O157:H7, and 20 and 60% for 24 h- and 48 h-enriched L. monocytogenes samples, respectively. The total filterable volume in commercially-generated waters was significantly higher for flume than for centrifuge water. All unenriched DEUF-C samples yielded E. coli O157:H7 and L. monocytogenes compared to 11.1 and 22.2%, respectively, for the unenriched grab samples. These findings indicate DEUF-C can improve the probability of detecting E. coli and Listeria in commercial wash water. However, filtration of commercial lettuce wash water remains challenging, with more work needed to ensure DEUF-C is feasible for commercial use.

Long‐term survival of blast pathogen in infected rice residues as major source of primary inoculum in high altitude upland ecology

Magnaporthe oryzae is the fungal plant pathogen that causes rice blast. The sources of primary inoculum and overwintering mode of the fungus remain largely unknown. The effect of rice residues on the onset of blast epidemics and the potential for survival of M. oryzae in the residues were studied in upland conditions in Madagascar. Blast disease was observed in a 3‐year field experiment in three treatments: with either infected or uninfected rice residues on the soil surface, or without rice residues. Leaf blast incidence was significantly higher in the treatment with infected rice residues than in the two other treatments at the early stages of the epidemic. In a second set of trials, the survival of M. oryzae on rice residues was monitored. Infected rice stems were placed by lots in three places: on the mulch of rice residues, under the mulch, and buried at a depth of 10 cm in the soil. Each month, samples were taken from the field and tested for sporulation. The survival of the blast fungus decreased rapidly on the stems buried in the soil but remained high for the other conditions. Sporulation of the fungus was observed on stems left on the mulch for up to 18 months. It is concluded that under field conditions, the presence of infected rice residues could initiate an epidemic of blast. The results of this study may help in designing effective management strategies for rice residues infected by M. oryzae.

Evaluating spray programs for managing copper resistant Pseudomonas syringae pv. tomato populations on tomato in the Limpopo region of South Africa

Bacterial speck of tomato caused by Pseudomonas syringae pv. tomato is an economically important disease in the Limpopo production region of South Africa. Two field trials were conducted to evaluate different spray programs for management of the disease. In the first trial, applications were only made in the field, and the main product evaluated was acibenzolar-S-methyl (ASM), with and without copper + mancozeb. In the second trial, spray programs were already started in the nursery and then continued in the field. The main products evaluated in the second trial were ASM and biological products. In the first trial, ASM field programs included a South African registration (3.75 g/100 L every 21 days), a USA registration (1.16 g/100 L to 2.63 g a.i./100 L every 14 days) and an ASM low rate (1.16 g/100 L weekly) application. These spray programs were all effective, and comparable in suppressing foliar infections and severely infected fruit (fruit with more than five lesions). The addition of copper + mancozeb to ASM spray programs did not improve control. In most of the first and second set of trials, the commercial standard of weekly applied copper + mancozeb was ineffective in suppressing foliar and fruit damage. It furthermore resulted in a significant increase in fruit infections in most trials. The ineffectiveness of copper + mancozeb spray programs, and programs that contained these compounds, were due to copper resistant P. syringae pv. tomato strains. The strains were identified in all trials through in vitro copper sensitivity testing. This was further confirmed through a tomato seedling bioassay using a copper resistant strain. In the second trial, starting spray programs in the nursery was beneficial. ASM applications in the nursery, followed by ASM + copper + mancozeb field applications were more effective in suppressing fruit infections, compared to only field applications of the latter products. The application of B. subtilis in the nursery, followed by field applied biologicals (B. subtilis and Microbacterium maritypicum) combined with ASM sprays, also improved the reduction of infected fruit, when compared to field only applications of ASM + copper + mancozeb.

An integrated vegetated ditch system reduces chlorpyrifos loading in agricultural runoff.

Agricultural runoff containing toxic concentrations of the organophosphate pesticide chlorpyrifos has led to impaired water body listings and total maximum daily load restrictions in California's central coast watersheds. Chlorpyrifos use is now tightly regulated by the Central Coast Regional Water Quality Control Board. This study evaluated treatments designed to reduce chlorpyrifos in agricultural runoff. Initial trials evaluated the efficacy of 3 different drainage ditch installations individually: compost filters, granulated activated carbon (GAC) filters, and native grasses in a vegetated ditch. Treatments were compared to bare ditch controls, and experiments were conducted with simulated runoff spiked with chlorpyrifos at a 1.9 L/s flow rate. Chlorpyrifos concentrations and toxicity to Ceriodaphnia dubia were measured at the input and output of the system. Input concentrations of chlorpyrifos ranged from 858 ng/L to 2840 ng/L. Carbon filters and vegetation provided the greatest load reduction of chlorpyrifos (99% and 90%, respectively). Toxicity was completely removed in only one of the carbon filter trials. A second set of trials evaluated an integrated approach combining all 3 treatments. Three trials were conducted each at 3.2 L/s and 6.3 L/s flow rates at input concentrations ranging from 282 ng/L to 973 ng/L. Chlorpyrifos loadings were reduced by an average of 98% at the low flow rate and 94% at the high flow rate. Final chlorpyrifos concentrations ranged from nondetect (<50 ng/L) to 82 ng/L. Toxicity to C. dubia was eliminated in 3 of 6 integrated trials. Modeling of the ditch and its components informed design alterations that are intended to eventually remove up to 100% of pesticides and sediment. Future work includes investigating the adsorption capacity of GAC, costs associated with GAC disposal, and real-world field trials to further reduce model uncertainties and confirm design optimization. Trials with more water-soluble pesticides such as neonicotinoids are also recommended. Integr Environ Assess Manag 2017;13:423-430. © 2016 SETAC.

Long-term retention of a divided attention psycho-motor test combining choice reaction test and postural balance test: A preliminary study

Driving in degraded psychophysical conditions, such as under the influence of alcohol or drugs but also in a state of fatigue or drowsiness, is a growing problem. The current roadside tests used for detecting drugs from drivers suffer various limitations, while impairment is subjective and does not necessarily correlate with drug metabolite concentration found in body fluids. This work is a validation step towards the study of feasibility of a novel test conceived to assess psychophysical conditions of individuals performing at-risk activities. Motor gestures, long-term retention and learning phase related to the protocol are analysed in unimpaired subjects. The protocol is a divided attention test, which combines a critical tracking test achieved with postural movements and a visual choice reaction test. Ten healthy subjects participated in a first set of trials and in a second set after about six months. Each session required the carrying out of the test for ten times in order to investigate learning effect and performance over repetitions. In the first set the subjects showed a learning trend up to the third trial, whilst in the second set of trials they showed motor retention. Nevertheless, the overall performance did not significantly improve. Gestures are probably retained due to the type of tasks and the way in which the instructions are conveyed to the subjects. Moreover, motor retention after a short training suggests that the protocol is easy to learn and understand. Implications for roadside test usage and comparison with current tests are also discussed.

Women and the post-war Nazi trials

Were women judged for crimes committed during the Nazi period? To attempt an answer to that question, one must make a distinction between the trials taking place immediately after the German capitulation in the different occupied zones, and those that were subsequently held in Nuremberg under new international law. The second set of trials concerned criminals holding responsibilities in the various organizations of the Nazi state: such responsibilities were not open to women. The earlier trials were held on the basis of existing laws, and concerned those who had personally, and with their own hands, perpetrated crimes. Analysis of these initial trials reveal that some very young women were condemned to death and hanged for crimes committed in the concentration camps.

Does Gut Passage Affect Post-dispersal Seed Fate in a Wild Chili, Capsicum annuum?

Abstract Seeds of Capsicum spp. (wild chilies ) are coated with capsaicin, which deters mammalian seed predators. During gut passage through frugivorous birds, its presence on seeds likely is greatly reduced, presumably increasing the seeds' susceptibility to postdispersal seed predation by mammals. We tested whether gut passage influences the rate at which dispersed seeds are removed from dispersal sites by different types of seed consumers. We predicted that seeds passed through birds (passed seeds) would be removed at higher rates than seeds taken directly from fruits (non-passed seeds). Removal rates of passed seeds were either lower or no different than removal rates of non-passed seeds, contrary to our prediction. In a second set of trials, we placed caged and exposed (control) seeds in pairs on the ground to determine whether vertebrates or invertebrates were primarily responsible for post-dispersal seed removal. We found an inconsistent effect of caging on frequency of seed removal, indicating tha...

Integrated management of Phytophthora capsici on bell pepper by combining grafting and compost treatment

In 2010 and 2011 an initial set of trials were carried out in order to evaluate the susceptibility of rootstocks used for grafting bell pepper (Capsicum annuum L.) in Italy to Phytophthora capsici, in comparison with widely used cultivars of pepper. In a second set of trials carried out in 2011 and 2012, grafting bell pepper onto resistant or partially resistant rootstock was combined with the use of compost-amended soil, to control Phytophthora blight. Trials were carried out in artificially or naturally infested soil, using five bell pepper cultivars (Fenice, Sienor, San Marco, Fiume, Cuneo) as susceptible not-grafted controls. In three trials, carried out in the presence of soil artificially infested with P. capsici, disease incidence in control plots ranged from 73 to 100% for the cvs. Cuneo and Fiume. Both cvs. Cuneo and Kaiman grafted on “Tecnico F1” rootstock provided complete control of P. capsici. A lower disease control, on the same cultivar, was provided by “Robusto” and “Capsifort”. On the cv. Fiume, “Terrano” provided complete control of the disease. By grafting all cultivars on “Robusto”, “Brutus”, “Snooker” and “Capsifort” a disease reduction by 68%–93%, 86%–100%, 67%–100% and 55%–78%, respectively, was provided. The general linear model analysis showed that for trials carried out under natural infestation the addition of compost to the soil, as well as the interaction of compost-amended soil with grafting, were significant factors influencing disease incidence reduction. The effect of grafting was a significant factor in reducing the percentage of diseased plants in all the trials. The addition of compost to the soil resulted in an effective and low-cost disease management solution, particularly when combined with susceptible not-grafted hybrids of bell pepper or when partially resistant rootstocks were used.

The effects of eight single microalgal diets on sex-ratio and gonad development throughout European flat oyster (Ostrea edulis L.) conditioning

To determine the effects of food quality on Ostrea edulis reproduction, European flat oysters were conditioned during two sets of experiments, carried out in spring and autumn, during 40days at 19°C, in 50l transparent flow-through tanks, in triplicate, and fed constantly at 900μm3μl−1, with eight different types of microalgae. Four species were fed per group of trials: Isochrysis affinis galbana, Chaetoceros gracilis, Skeletonema marinoï, and Tetraselmis suecica were fed to flat oysters in the first set; whereas Rhodomonas salina, Thalassiosira weissflogii, Thalassiosira pseudonana, and Pavlova lutheri were provided during the second set of experiments. At the beginning and end of both conditioning periods, oysters were sampled and processed for histology analysis for each diet. Each oyster was classified for its sex and gonad development stage. Oysters fed S. marinoï and C. gracilis exhibited the highest ratio of hermaphrodites with 96 and 77% respectively, whereas those fed T. suecica showed the lowest hermaphrodite percentage, 59%. When oysters were conditioned throughout the second set of experiments with four other species, oysters fed R. salina and T. weissflogii exhibited 83 and 87% of hermaphrodites. Regardless of the diet, a gonad development occurred during the first set of experiments with ≥60% ripe oysters (stage 3) and spawned oysters (stage 4). In the second set of trials, oysters fed R. salina and T. weissflogii were highly mature with 90% and 75% of stage 3 and stage 4 respectively; whereas those fed P. lutheri showed low maturation with only 17% of ripe oysters.

Cattle preference for forage kochia, crested wheatgrass, and velvet lupine

ABSTRACT Alkaloids in velvet lupine (Lupinus leucophyllus Douglas ex Lindl.) cause a crooked calf syndrome if the dam consumes the plant between d 40 and 100 of gestation. In spring calving operations, this coincides with late summer when annual grasses are mature and senescent in the Scabland region of eastern Washington. Velvet lupine is the only green-growing forb during this period on the annual grasslands and is readily consumed. Planting an alternative forage that is more palatable than velvet lupine may reduce the risk of crooked calves. Preference trials were conducted to compare the palatability of 2 varieties of forage kochia, ‘Immigrant’ (Kochia prostrata ssp. virescens) and the experimental line Otvsel (K. prostrata ssp. grisea), with crested wheatgrass (Agropyron desertorum [Fisch. ex Link] Schult.) and velvet lupine. Preferences were ranked by sequential Latin squares. The first trial consisted of four 4 × 4 Latin squares: 4 forages, 4 heifers, 4 d, and 4 feed locations. The most preferred forage was then removed and preference for the remaining forages was evaluated in a 3 × 3 Latin square. The 2 trials were repeated using 4 new heifers. Crested wheatgrass was preferred in the first trial, but the Immigrant forage kochia replaced it as most preferred feed in the second set of trials. There was no difference in preference between Otvsel and velvet lupine. Results indicate that Immigrant forage kochia and crested wheatgrass should be selected to evaluate their establishment and palatability in subsequent seeding and field-scale palatability trials in the Scabland region of eastern Washington.

Response of Potatoes to Soil-Applied Insecticides, Fungicides, and Herbicides

Non-target impacts of pesticides are well documented in crops such as soybeans and corn. However, little effort has been made to evaluate these impacts in potatoes. Field trials were conducted at the Parma and Aberdeen Research and Extension Centers during 2005 and 2006 to evaluate the potential for systemic insecticides, fungicides, and herbicides to affect disease development, crop injury, and tuber yield. The first set of trials evaluated six insecticide treatments (aldicarb, oxamyl, phorate, imidacloprid, thiamethoxam, and non-treated) in a factorial combination with in-furrow application of the fungicide azoxystrobin. Azoxystrobin significantly decreased Rhizoctonia stem canker, while aldicarb and phorate tended to increase it compared to the non-treated control. There was a significant insecticide by fungicide interaction due to a bigger reduction in disease index by the fungicide when certain insecticides were used. Despite the association of these insecticides with increased disease incidence, there was no significant impact on yield. In the second set of trials, sulfentrazone herbicide was applied just prior to plant emergence to potatoes treated with the same six insecticides to evaluate the potential for the in-furrow treatments to increase plant injury. Sulfentrazone caused stunting and visible plant injury, but the level of plant injury was influenced by insecticide treatment in only one out of four trials.

Optimality vs. variability: an example of multi-finger redundant tasks

Two approaches to motor redundancy, optimization and the principle of abundance, seem incompatible. The former predicts a single, optimal solution for each task, while the latter assumes that families of equivalent solutions are used. We explored the two approaches using a four-finger pressing task with the requirement to produce certain combination of total normal force and a linear combination of normal forces that approximated the total moment of force in static conditions. In the first set of trials, many force-moment combinations were used. Principal component (PC) analysis showed that over 90% of finger force variance was accounted for by the first two PCs. The analytical inverse optimization (ANIO) approach was applied to these data resulting in quadratic cost functions with linear terms. Optimal solutions formed a hyperplane ("optimal plane") in the four-dimensional finger force space. In the second set of trials, only four force-moment combinations were used with multiple repetitions. Finger force variance within each force-moment combination in the second set was analyzed within the uncontrolled manifold (UCM) hypothesis. Most finger force variance was confined to a hyperplane (the UCM) compatible with the required force-moment values. We conclude that there is no absolute optimal behavior, and the ANIO yields the best fit to a family of optimal solutions that differ across trials. The difference in the force-producing capabilities of the fingers and in their moment arms may lead to deviations of the "optimal plane" from the subspace orthogonal to the UCM. We suggest that the ANIO and UCM approaches may be complementary in the analysis of motor variability in redundant systems.

A New Approach for the Measurement of Film Thickness in Liquid Face Seals

Face seals operate by allowing a small volume of the sealed fluid to escape and form a thin film between the contacting parts. The thickness of this film must be optimized to ensure that the faces are separated, yet the leakage is minimized. In this work the liquid film is measured using a novel ultrasonic approach with a view to developing a condition monitoring tool. The trials were performed in two stages. Initially tests were based on a lab simulation, where it was possible to compare the ultrasonic film thickness measurements with optical interference methods and capacitance methods. A direct correlation was seen between ultrasonic measurements and capacitance. Where ultrasonic and optical methods overlap, good correlation is observed; however, the optical method will not record film thickness above ∼ 0.72 μ m. A second set of trials was carried out, where the film thickness was monitored inside a seal test apparatus. Film thickness was successfully recorded as speed and load were varied. The results showed that while stationary the film thickness varied noticeably with load. When rotating, however, the oil film remained relatively stable around 2 μ m. During the normal operation of the seal, both sudden speed and load changes were applied in order to initiate a seal failure. During these events, the measured film thickness was seen to drop dramatically down to 0.2 μ m. This demonstrated the ability of the technique to predict failure in a face seal and therefore its aptitude for condition monitoring.