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Our primary objective in this study was to determine the plant level and environmental factors that affect oviposition choice and subsequent offspring survival in Megathymus yuccae (Boisduval and Leconte) on its host plant, Yucca filamentosa L. A preliminary survey suggested that the frequency of pupal eclosion tent presence increased only with host plant height. In an expanded survey conducted during the adult flight period the following spring, we found that plant height increased the probability of oviposition, whereas the density of herbaceous stems and fire damage decreased the probability of egg presence. Similarly, the number of eggs on occupied plants increased with plant height arid decreased with fire damage. When we surveyed the plants from the spring 2008 sampling the following winter to determine presence of late-instar larvae or pupae, we found that the probability that at least one larva survived on previously occupied plants decreased with the density of herbaceous stems. These results collectively suggest that larger, unburned Y. filarnentosa individuals and those in relatively open areas are more attractive as host plants for oviposition and that larval performance is generally, but not exclusively, consistent with female preference in this system. [ABSTRACT FROM AUTHOR]

Crossbred beef steers (n = 96) were utilized in a study conducted at the University of Nebraska-Lincoln Agricultural Research and Development Center research feedlot near Mead, NE to determine the effect of feeding Agrimos (Lallemand Animal Nutrition; Montreal, Canada) and 2.5-cm ground wheat straw to finishing steers during the summer on body temperature and panting score in addition to performance, carcass characteristics and blood metabolites. Three treatments with 4 replications per treatment were set up in a completely randomized design. Treatments consisted of abasal control diet (CON); consisting of 68.5% corn 20% modified distillers grains plus solubles, 7.5% sorghum silage, and 4% supplement, the inclusion of Agrimos (MOS; 30 g/steer daily), and 2.5-cm ground wheat straw replacing 5% corn (WHT). Cattle were stratified by initial BW between pens and pen was assigned randomly to treatment. Rumen boluses to collect body temperature were inserted on d 21 of the trial after cattle were adapted to finishing diets. Blood was collected in July and August (7 collection wk) of the trial via jugular venous puncture. There were no differences (P > 0.19) observed for final BW, ADG, and DMI among treatments. Additionally, no difference (P > 0.24) was observed for carcass-adjusted final BW or ADG. Feed efficiency was decreased (P < 0.02) on both a live- and carcass-adjusted basis for cattle fed WHT when compared to CON and MOS. Hot carcass weight, dressing %, LM area, and marbling score were not different (P > 0.36) among treatments. Cattle fed the CON had greater 12th rib fat depth and USDA yield grade (P < 0.02) than cattle fed WHT and MOS. Both average and maximum body temperatures were greater (P < 0.01) for cattle fed MOS than for cattle fed CON or WHT. There was no difference (P = 0.18) for area under the curve body temperature between treatments. Panting scores were least (P < 0.01) for cattle fed the WHT when compared to CON and MOS. Time and treatment interactions (P < 0.05) were observed for bilirubin, blood urea nitrogen, calcium, chloride, carbon dioxide, creatinine, potassium lactate dehydrogenase, phosphorus, total protein, triglyceride, uric acid red blood cell count, hemoglobin, and hematocrit levels. No effect on animal performance was realized from the addition of Agrimos to the diet, however, body temperature was increased slightly. Adding 5% finely ground wheat straw decreased G:F and reduced panting score but did not affect body temperature. [ABSTRACT FROM AUTHOR]

Two finishing trials were conducted utilizing 80 crossbred beef steers (in each) across 2 seasons (summer and winter, initial BW = 489 ± 20.4,387 ± 15.9 kg, respectively) at the University of Nebraska-Lincoln Agricultural Research and Development Center near Mead Neb. Continuous rumen temperature was collected tiiroughout die duration of both trials. Blood samples were taken via jugular venous puncture every 2 wk until 4 wk before harvest for a total of 6 collections during the summer and 8 collections during the winter. Came in both trials were fed the same diet consisting of 51% HMC, 40% Sweet Bran, 5% wheat straw, and 4% supplement. Individual steer rumen temperature was used in the statistical model as a covariate. Only blood measures where rumen temperature was significant as a covariate were chosen to be reported. These selected blood measures were correlated to the 3-d prior average environmental temperature and the 3-d comprehensive climate index (CCI) relative to that blood collection day. Correlations between the change in blood measures and the respective change in rumen temperature, across collection points, were also analyzed. Additionally, environmental conditions were correlated to DMI and rumen temperature. Direct bilirubin, red blood cell count, hematocrit, and hemoglobin levels were all correlated (R > 0.22), during at least one season, to both the 3 d average environmental conditions and 3-d rumen temperature. Lactate dehydrogenase was negatively correlated (R < -0.62) to both 3-d averaged environmental conditions during the winter trial and also during the summer trial (R > -0.28). Red blood cell count was negatively correlated (R < -0.23) to 3-d environmental conditions during the winter trial however, was not correlated (R > -0.10) to environmental conditions during the summer trial. Rumen temperature was positively correlated to CCI and environmental temperature (R = 0.65, R = 0.63; respectively) during the summer During the winter, rumen temperature was negatively correlated to CCI and environmental temperature (R = -0.27 and R = - 0.19). Intake was negatively correlated to both CCI and environmental temperature (R = -0.32; R = -0.30) in me summer trial, however, during the winter trial DMI was positively correlated to CCI and environmental temperature (R = 0.22 andi? = 0.24). Some blood metabolites change in accordance to environmental conditions and may be important during times of environmental stress. Additionally, environmental conditions affect both DMI and rumen temperature. [ABSTRACT FROM AUTHOR]

Toward improving DNA separations, this work reports the effects of high-frequency square-wave AC fields superimposed perpendicular to the direct current (DC) separation field on DNA migration in both polyacrylamide-based interpenetrating networks (IPNs) and in agarose networks. Compared to standard polyacrylamide gels, IPNs allow the separation of larger DNA (9000 bp vs. 5000 bp at 5 V/cm). In novel polyacrylamide-based IPNs, an alternating current (AC) field of 5 Hz increased the maximum DNA size separable. This effect was extended to larger DNA sizes with increasing electric-field strength up to and apparently beyond the power supply-limited maximum electric-field strength of 48 V/cm. The orthogonal AC field also increased mobility. These two results combine to yield a reduction in separation time of up to a factor of 20 in novel polyacrylamide-based IPNs. When negatively charged acrylic-acid groups were incorporated into the IPNs, the use of the AC field changed the DNA-network interaction, which altered the size dependence of DNA mobility. In agarose gels, an AC field of 50 Hz increased the size range separable; however, there was no increase in DNA mobility. There was no change in size dependence of mobility in an AC field when the number of charged groups in the agarose network was increased. Based on results in the literature, possible mechanisms were examined for the effects of the AC field on DNA separation.