Marc A. Evans

High-fat dairy product consumption increases Δ9c’ 11t−18∶2 (rumenic acid) and total lipid concentrations of human milk

Conjugated octadecadienoic acids (18∶2’ conjugated linoleic acids) have been shown to be anticarcinogenic and may influence growth and nutrient partitioning. The Δ9c’ 11t−18∶2 isomer (rumenic acid’ RA) is most common in both food sources and human tissues. To determine if maternal diet can influence milk RA concentration’ breastfeeding women (n=16) were enrolled in a 3-wk crossover study. Women initially consumed minimal amounts of food containing RA during week 1’ then were assigned randomly to consume diets rich in high-fat dairy foods (and thus RA) during week 2 or 3. Milk was collected by complete breast expression twice during each experimental week. Current and chronic RA intakes were estimated by 3-d dietary records and food frequency question-naires’ respectively. Estimated chronic RA intakes ranged from 49 to 659 mg/d. Dietary RA intake was greater during the high compared to the low dairy period (291±75 vs. 15±24 mg/d’ respectively; P<0.0001). Milk contained more RA during the high than the low dairy period (13.5±0.1 vs. 8.2±0.4 μmol/g lipid’ respectively; P<0.0001). Milk lipid concentration was influenced by diet’ such that lipid concentration was greater during the high than the low dairy period (46.6±5.0 vs. 38.3±1.6 mg/g milk’ respectively; P<0.05). Additionally’ multiple regression analyses suggested that body mass index was the primary predictor of milk RA and lipid concentrations. In summary’ these data indicate that both lipid and RA concentrations of human milk can be influenced by diet.

Coordination of Leaf Photosynthesis, Transpiration, and Structural Traits in Rice and Wild Relatives (Genus Oryza)

Linkages of leaf and mesophyll cell traits to CO2 diffusion, photosynthesis, transpiration, and water use efficiency were identified across accessions of the genus Oryza. The genus Oryza, which includes rice (Oryza sativa and Oryza glaberrima) and wild relatives, is a useful genus to study leaf properties in order to identify structural features that control CO2 access to chloroplasts, photosynthesis, water use efficiency, and drought tolerance. Traits, 26 structural and 17 functional, associated with photosynthesis and transpiration were quantified on 24 accessions (representatives of 17 species and eight genomes). Hypotheses of associations within, and between, structure, photosynthesis, and transpiration were tested. Two main clusters of positively interrelated leaf traits were identified: in the first cluster were structural features, leaf thickness (Thickleaf), mesophyll (M) cell surface area exposed to intercellular air space per unit of leaf surface area (Smes), and M cell size; a second group included functional traits, net photosynthetic rate, transpiration rate, M conductance to CO2 diffusion (gm), stomatal conductance to gas diffusion (gs), and the gm/gs ratio. While net photosynthetic rate was positively correlated with gm, neither was significantly linked with any individual structural traits. The results suggest that changes in gm depend on covariations of multiple leaf (Smes) and M cell (including cell wall thickness) structural traits. There was an inverse relationship between Thickleaf and transpiration rate and a significant positive association between Thickleaf and leaf transpiration efficiency. Interestingly, high gm together with high gm/gs and a low Smes/gm ratio (M resistance to CO2 diffusion per unit of cell surface area exposed to intercellular air space) appear to be ideal for supporting leaf photosynthesis while preserving water; in addition, thick M cell walls may be beneficial for plant drought tolerance.

Winter foraging ecology of woodland caribou in northeastern washington

To better understand late winter foraging ecology of woodland caribou (Rangifer tarandus caribou) feeding on arboreal lichens, we used bottle-raised caribou in experimental arena trials with artificial trees, and in field trials within historical late-winter habitat. Factors with the greatest influence on intake rate differed between experimental arena and field trials. Bite size was the most important variable in experimental arena trials; bite rate was the most important in field trials. During late winter field trials, caribou foraged on lichen primarily on standing subalpine fir (Abies lasiocarpa) and dead trees. Bite size, bite rate, intake rate, tree resident time, and amount of lichen eaten per tree were included in a general linear model with tree species, tree size class, and tree lichen class ( average) as the independent variables. Tree lichen class was the most important variable in the model and 76% of all bites occurred on >average lichen class trees. Compared to theoretical maximums, intake rate was low on all lichen class trees (range = 1.4-2.1 g/min). At these intake rates caribou would have to forage 14-21 hours to meet predicted daily requirements. Tree resident time and time between trees varied inversely with tree density. In cafeteria style preference trials with the 2 primary arboreal lichen genera, caribou strongly preferred Bryoria spp. (92%) compared to Alectoria sarmentosa (8%). Apparent dry matter digestibility of this diet was 82%. Timber stands must be substantially older than traditional harvest rotation lengths to provide the high lichen biomass found on >average lichen class trees. Caribou remained in habitats where Bryoria was the predominant genus of arboreal lichen and would not forage in A. sarmentosa dominated valley bottom habitat.

Viability and development of diploid and triploid salmonid hybrids

Abstract Three single-pair matings were made of each possible cross among Atlantic salmon (Salmo salar), brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), chum salmon (Oncorhynchus keta), coho salmon (Oncorhynchus kisutch), and rainbow trout (Oncorhynchus mykiss). Portions of fertilized eggs from each of the 108 matings were heat shocked to induce triploidy. Analysis of development in 9- and 18-day-old embryos showed that hybrids with a high proportion of malformed embryos usually also showed poor survival. Diploids usually survived better than triploids in within-species matings but poorer in hybrids. Crossing a female from a rapidly developing species with a male from a more slowly developing species usually produced progeny with greater viability than the reciprocal cross, and closely related species usually produced more viable hybrid progeny than did more distantly related species. Although no new hybrids that show potential for aquaculture purposes were identified, the experiments confirmed the potential utility of some hybrids and identified crosses which may be useful for gynogenesis.

C-reactive protein in the differentiation of pyometra from cystic endometrial hyperplasia/mucometra in dogs.

Hematological parameters, plasma C-reactive protein (CRP), and tumor necrosis factor alpha were analyzed in 64 dogs with a presumptive diagnosis of pyometra. Final diagnosis (i.e., pyometra or cystic endometrial hyperplasia [CEH]) was determined by histopathology. As a single test, the percentage of band neutrophils had the highest sensitivity in the prediction of pyometra (sensitivity, 94%). The combination of percentage of bands and CRP had the highest sensitivity (97.7%; specificity, 75%) in predicting the presence of pyometra. The most common clinical signs noted in the study were vaginal discharge, polyuria, polydipsia, lethargy, and gastrointestinal signs. A combination of three or more of these clinical signs was significantly associated with pyometra.

Habitat Conditions Associated With Lynx Hunting Behavior During Winter in Northern Washington

Abstract Effectively managing habitat for threatened populations of Canada lynx (Lynx canadensis) requires knowledge of habitat conditions that provide for the ecological needs of lynx. We snow-tracked lynx to identify habitat conditions associated with hunting behavior and predation during winters of 2002–2003 and 2003–2004 in the northern Cascade Range in Washington state, USA. We recorded number and success of predation attempts, prey species killed, and trail sinuosity on 149 km of lynx trails. Lynx killed snowshoe hares (Lepus americanus), red squirrels (Tamiasciurus hudsonicus), and cricetids more than expected in Englemann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) forests, where snowshoe hare densities were highest. Lynx killed prey less than expected in Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) forests and forest openings. We used the sinuosity of lynx trails as an index of quality of habitat hunted. Lynx trails that included predation attempts were more sinuous than trail segments without predation attempts. Lynx trails had greater sinuosity in forest stands with high hare densities dominated by Engelmann spruce and subalpine fir than in stands with low hare densities dominated by Douglas-fir and ponderosa pine or in forest openings. We encourage forest managers to maintain or create sufficient understory cover to support high densities of snowshoe hares as foraging habitat for lynx.

A general theory for modeling capture-recapture data from a closed population.

A general theory for estimating the size of a closed population from multiple-recapture data is presented. This theory is easily extended to open population models for multiple-recapture data. Estimation is based on a log-linear model developed for modeling dependent capture-recapture data when capture probabilities vary temporally with behavioral response and are heterogeneous among animals. Models for complete capture history data are developed along with the first log-linear models for removal data. The maximum likelihood estimator of the model parameters along with the estimated covariance matrix are presented.

Bias reduction for multiple-recapture estimators of closed population size.

A bias correction for multiple-recapture sampling is proposed. The correction is similar to Chapmans (1951, University of California Publication in Statistics 1, 131-160) correction of the Lincoln-Petersen estimator of population size. Small-sample properties of the modified population size estimator are examined using Monte Carlo simulation. Substantial reductions in estimator bias and variance are obtained with the modified estimator.

Autumn foraging dynamics of woodland caribou in experimentally manipulated habitats, northeastern Washington, USA.

Foraging options of woodland caribou (Rangifer tarandus caribou) in the high snowpack ecosystems of western North America become narrowed after freezing temperatures in antumn precipitate leaf-drop in deciduous shrubs. The objectives of this research were to determine the influence of (1) removing arborca lichen (Ascompecytes) on windthrown trees and myrtle boxwood (Pachistime myrsinites) and (2) stand type (oldgrowth versus clearcnt) on woodland caribou foraging dynamics during autum. Foraging trials were conducted with 3 tame woodland caribou in 6 0.5-ha pens. In 3 treatment pens all windthrown arboreal lichen-bearing trees were removed from the old-growth portion of the pen and extant invrtle hoxwood plants were removed from the entire pen. In the 3 control pens all extant windthrown trees and invrtle boxwood plants were retained In addition, pens were constructed such that half of each pen was in an old-growth stand of western red-cedar (Thuja plicata)-western hemlock (Tsuga heterophylla) and half was in an adjacent clearent. Arboreal hcher had the greatest influence on dry-matter intake rate (DMIR) because of the large bite size provided by this forage. In control pens, caribou had higher DMIR (P = 0.006) and crude protein intake rate (CPIR) (P = 0.007) than in treatment pens where lichen-bearing windthrown trees had been removed. Arboreal lichen from windthrown trees was 52% (range 43-61) of the total DMI in the old-growth portious of control pens Arboreal lichen from windthrown trees comprised 81% (range = 75-92) of the arboreal lichen bites (i.e., 19% of arboreal lichen bites were from litterfall and standing trees), and 28% range = 16-48) of total bites in the timbered portion of control peus. The DMIR (P = 0.004) and CPIR (P = 0.004) of caribou was also greater in old-growth than in clearcat portions of pens. Search time was greater (P = 0.008) in clearent portions or pens than in old-growth portions. Myrtle boxwood comprised <0.4% of caribou diets. These data suggest that arboreal lichen is an important dietary component earlier in antamn than previously reported.

Considerations for measuring genetic variation and population structure with multilocus fingerprinting

Multilocus DNA fingerprinting provides a cost‐effective means to rapidly assay genetic variation at many loci. While this makes the technique particularly attractive for studies of evolution and conservation biology, fingerprint data can be difficult to interpret. Measurement errors inherent with the technique force investigators to group similar‐sized alleles (bands) into discrete bins before estimating genetic parameters. If too little error is accounted for in this process homologous alleles will not be grouped in a common bin, whereas overestimated error can produce bins with homoplasic alleles. We used simulations and empirical data for two frog species (Rana luteiventris and Hyla regilla) to demonstrate that mean band‐sharing (S¯xy) and heterozygosity (H¯E) are a function of both bin width and band profile complexity (i.e. number and distribution of bands). These estimators are also sensitive to the number of lanes included in the analysis when bin width is wide and a floating bin algorithm is employed. Multilocus estimates of H¯E were highly correlated with S¯xy and thus provide no additional information about genetic variation. Estimates of population subdivision (F^ and Φ^ST) appeared robust to changes in bin size. We also examined the issue of statistical independence for band‐sharing data when comparisons are made among all samples. This analysis indicated that the covariance between band‐sharing statistics was very small and not statistically different from zero. We recommend that sensitivity analyses for bin size be used to improve confidence in the biological interpretation of multilocus fingerprints, and that the covariance structure for band‐sharing statistics be examined.