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A symbiotic relationship exists between the endophytic fungus, Acremonium coenophlalumMorgan‐Jones and Gains and tall fescue (Festuca arundinaceaSchreb.). The response of the host planto the endophyte has been studied by comparing infected or noninfected populations in the field or by an individual plant genotype in the greenhouse. The lack of a more thorough investigation of tall fescue genotypes with and without their endophytes suggests that known responses of tall fescue plants to endophyte infection are limited to the restricted conditions by which they were tested. The objectives of this study were to determine variability in responses of tall fescue genotypes to endophyte infection for select growth characteristics, plant morphology, and chemical components. Five genotypes of tall fescue were grown in both endophyte‐infected (EI) and noninfected (NI) forms in the greenhouse under different clipping treatments. Tiller and dry matter production, crown depth, and total nonstructural carbohydrates (TNC) were measured. In addition, leaf area per plant (LAP), specific leaf weight (SLW), and ergovaline duction were measured on two diverse plant genotypes. Forage yield, tiller number, and TNC varied for EI and NI treatments among plant genotypes. Dry matter production per tiller was greater and crown depth was approximately 1‐cm lower in EI plants than NI plants. Leaf area was greater in EI plants but SLW was higher in EI Genotype 7 (3.94 vs. 3.65 mg cm−2) and lower in El Genotype 17 (4.25 vs. 4.91 mg cm‐2) compared to their NI forms. Ergovaline production was constant regardless of leaf area in Genotype 7, but increased linearly with leaf area in Genotype 17. We conclude that endophytes increased phenotypic variation in this study and thus may increase the ability of mixed EI and NI populations to adapt to diverse environments.

Fifty-four Hereford steers and heifers, equally divided into three groups, were grazed on fescue grass for 180 days. One group was slaughtered after the grazing period and the two remaining groups were fed a high concentrate diet for 56 and 112 days. Longissimusand semitendinosusmuscle characteristics of these animals were determined. Carcass quality grades improved with grain feeding. Sarcomeres were longer and fiber diameters were generally less for semitendinosusthan for longissimusmuscles. Percent moisture declined and ether extractable constituents increased in both muscles as period of grain feeding was increased. Percent protein did not change with grain feeding but was higher for longissimusthan for semitendinosus. Collagen content did not change in semitendinosusbut declined in longissimusas determined from histological sections. Amount of reticulin did not differ among muscles or due to feeding treatment. Elastin was greater in semitendinosusthan in longissimus. Tenderness of both muscles improved with grain feeding but declined for both muscles as internal temperatures were increased from 63 to 68 to 73 C.

1. The mechanisms underlying the exercise hyperpnoea have been difficult to define. Recently it has been suggested that exercise ventilation (VE) changes in proportion to changes in arterial potassium concentration ([K+]a). Similar VE and [K+]a time courses following work rate changes have been cited as supporting evidence. This study compared [K+]a and VE dynamics during moderate exercise in man. 2. We observed VE and gas exchange responses in five healthy men to sinusoidal work rate variation between 25 and approximately 105 W. Tests of approximately 30 min duration were performed at sinusoidal periods of 9, 6 and 3 min and in the steady state. In each test, during two or three sine periods, arterial blood was sampled (24 per test) and analysed for [K+] and blood gases. Response amplitude and phase (relative to work rate) were determined for each variable. 3. [K+]a fluctuated in response to sinusoidal work rate forcing with mean‐to‐peak amplitude averaging 0.15 mmol 1(‐1). However, among tests, VE amplitude and phase were not highly correlated with [K+]a (r = 0.36 and 0.67, respectively). Further, average [K+]a amplitude in the 9 and 6 min sinusoidal studies tended to exceed the steady‐state amplitude, while average VE amplitude fell progressively with increasing forcing frequency. The dissimilar dynamics of [K+]a and VE seem inconsistent with a major role for [K+]a as a proportional controller of ventilation during non‐steady state moderate exercise in man. 4. Among tests, VE and CO2 output (VCO2) amplitude and phase were closely correlated (r = 0.87 and 0.94, respectively). Further, arterial CO2 pressure (Pa,CO2) and arterial pH(pHa) did not fluctuate significantly in ten of twenty and thirteen of twenty studies, respectively. In tests where sinusoidal fluctuation was detected, amplitude averaged 1.1 mmHg and 0.008 units, respectively. Thus VE demonstrated a close dynamic coupling to CO2 output, with consequent tight regulation of Pa,CO2 and pHa.

Assessing livestock preference for entries of forage breeding programs is important because livestock defoliate plants discriminantly, and thus influence plant competition and survival. We compared seven non‐destructive methods for evaluating tall fescue (Festuca arundinaceaSchreb.) defoliation. Cross‐section, height, and spread measurements from a grid; hemisphere, cube, and cylinder formulae applied to height and diameter; and settling plate measurements were regressed against non‐subjective determinations using a plane table. The hemisphere equation applied to height and diameter assessed defoliation best. Coefficients of determination ranged from 0.07 to 0.85 for the plate method and hemisphere formula respectively. Our results reflect vegetative plants. Other methods may be better for taller plants.

The effect of production system on beef palatability and carcass characteristics was studied. Weanling steer calves (351 Hereford-Angus crossbred) were allotted to four production systems consisting of 13 dietary treatments: (I) drylot fed corn silage for 203 d, followed by grain feeding for 69 and 102 d; (II) winter backgrounding followed by spring and summer grazing (tall fescue and tall fescue-red clover), then grain on pasture for 67 and 88 d; (III) winter backgrounding followed by spring and summer grazing on tall fescue, tall fescue-red clover and tall fescue-birdsfoot trefoil, and (IV) winter backgrounding and grazing same as system III, followed by grain in drylot for 123 d. Carcasses from the grass-fed animals had lower quality grades, higher cutability and darker color lean (P<.05) than that of carcasses from the other treatments. Loin steaks from grass-fed animals were less desirable in flavor, juiciness, tenderness and overall acceptability (P<.05), while top round roasts were rated less desirable in flavor and overall acceptability (P<.05) than similar cuts from the other dietary treaments. Essentially no differences in sensory characteristics or shear values were noted for steaks and top round roasts between any of the other treatments. Steaks and roasts from silage-fed animals were rated equally acceptable in tenderness and other sensory characteristics as steaks and roasts from animals finished on grain in drylot or on pasture. Longer periods of grain feeding generally increased carcass fat, but did not improve sensory characteristics of steaks and roasts compared with shorter periods of grain feeding.

Rapid, nondestructive methods of estimating herbage mass (HM) are vital to experiments involving frequent collection of data, especially where physical sampling may alter growth. Herbage mass estimation techniques are based on double‐sampling, in which clipped HM and corresponding nondestructive sward measurements are used in regression analysis to obtain prediction equations. Our objective was to evaluate the precision and accuracy of sward height (SH), ground cover (GC), and disk height (DH) as predictors of HM in alfalfa (Medicago sativaL.) at weekly intervals after cutting. Sward height was measured with a sliding crossbar on an upright meter stick. Ground cover was estimated using a 0.18‐ by 0.22‐m grid subdivided into 20 cells. Disk height was measured with 0.96‐ and 1.76‐kg, 0.2‐m2aluminum disks, allowed to settle on the sward canopy. All nondestructive measures were accompanied by clipping ofthe areas measured. Clipped HM ranged from 12 to 794 g m−2. Herbage mass prediction equations were developed following stepwise regression of sample HM on SH, DH, GC, days of growth, and derived variables. The most precise HM prediction models were based on SH and DH, accounting for 79 to 94% of variation in HM of calibration samples. Applying prediction equations to a validation data set generated predicted HM values. Sward height and DH models accounted for 59 to 86%, and 80 to 97%, respectively, of the variation in HM of validation samples. Herbage mass of validation samples was predicted with lower standard errors of validation by DH models (19.5–35.9 g m−2) than by SH models (60.8–65.6 g m−2) on the same stands in the same year. The disk technique provides a rapid, accurate means of nondestructively monitoring growth in alfalfa plots.

Geostrophic wind velocities were calculated using atmospheric pressure data from Bering Strait stations at Uelen (Siberia), Bukhta Provideniya (Siberia) and Nome (Alaska). These velocities were matched to Strait sea ice displacements derived from satellite imagery (1974–1984), resulting in an all-weather ice movement and now-casting model. Also, five ice displacement modes were identified. The first mode is Chukchi to Bering Sea movement when northeasterly winds exceed 11.5 m/s. The second and third modes are Bering to Chukchi Sea movement. Mode two is driven by a pre-existing north-flowing ocean current during weak opposing winds. Mode three is due to winds and currents acting in concert. The first immobilization mode (maximum duration one week) is an apparent balance between northerly wind stress, water stress from the south, and internal ice stresses. The second immobilization mode is due to large, double, solid ice arches jamming the Strait up to four weeks.

Stand thinning has been observed when N‐fertilized cool‐season grasses are harvested in late spring. These losses appear to be greater when hot, clear weather follows a harvest. Earlier spring cuts appear to ameliorate the stress. This 2‐year investigation examined effects of spring N at 50 and 160 kg/ha; and spring cutting (biweekly, monthly, and zero spring cuts) to 5 and 10 cm stubbles on regrowth of tall fescue (Festuca arundinaceaSchreb.). Stubble canopy structure, microenvironment, and stand regrowth were examined following a June harvest at which all plots were moved at their respective cutting heights (save an unharvested check). The high N rate caused greater forage yields to be present at the June harvest. Stubble leaf area index (LAI), vegetative tiller density, and live stubble yields were not affected by N rate. Cutting during spring increased tiller density and LAI. Cutting managements had significant effects on the stubble temperafure and soil temperature that were associated negatively with stubble LA1 and tiller density. There was no detrimental effect of cutting management or N rate on stand recovery except in 1975 when lodged areas of spring accumulated swards with high N fertilization had poor regrowth. Stand losses in these area was associated with only 3 to 4% noncarbohydrates (TNC) in the stubble. Lodging is hypothesized to be partially responsible for stand losses in dense stands through detrimental effects on TNC storage and other unknown effects.

The availability and the choice of appropriate comparison groups are essential for valid occupational epidemiologic studies. Too often, however, adequate comparison groups cannot easily be found within a workplace environment or extracted from the general population. An evaluation of the efficacy of using a pool of comparison subjects from the health and Nutrition Examination Survey (HANES) was performed on data gathered by the National Institute for Occupational Safety and Health in 1979. Comparison groups from the HANES pool were derived for 246 workers at four different commercial/industrial facilities in the Niagara Falls, New York, area and the comparability between the groups was assessed for several demographic, behavioural, and biomedical variables. The HANES groups exhibited a high degree of comparability with regard to most variables, excluding ancestry. The HANES pool may serve as a useful source of subjects to allow for the comparison of disease rates where occupational exposure is the key distinguishing feature between groups.

Tall fescue (Festuca arundinaceaSchreb.) is a common pasture grass adapted to a wide range of environmental conditions. An endophyte, Acremoninm coenophialum Morgan‐Jones & Gams, growing in association with tall fescue is known to produce ergopeptine alkaloids that are thought to be detrimental to animal health. Endophyteinfection changes how tall fescue plants grow and may be involved in the adaptability of tall fescue to environmental extremes. The objective of this study was to determine whether plant‐endophyte associations that had previously tested as high and low ergopeptine alkaloid producers varied in competitive ability when their endophytes were removed. Two identical field studies were conducted on a Cecil sandy clay loam and a Pacolet sandy clay loam soil (both clayey, kaolinitic, thermic Typic Hapluduits) in 1987 and 1988, respectively. In each study, a modified Nelder's design was used to test the competitiveness between infected and noninfected forms of two tall fescue genotypes. Endophyte‐infected plants were larger and, generally, more competitive in mixtures with noninfected plants. When infected with endophyte, the high ergopeptine alkaloid‐ producing genotype of tall fescue had similar or reduced competitiveness than the low‐alkaloid genotype when compared with their noninfected forms. We conclude that if ergopeptine alkaloids can be genetically removed from tall fescue‐endophyte associations, the competitiveness of the plant would be unaffected in nongrazed conditions. Reduction or elimination of ergopeptine alkaloids would help improve animal health when consuming endophyte‐infected tall fescue forage.

An analysis of remotely sensed imagery of the Exxon Valdez oil spill is described and the usefulness of the various wavelengths and platforms available (Landsat, AVHRR, SPOT) is discussed. The spill was sufficiently large that the main body could be detected by the low resolution (I km) AVHRR system. However the higher resolution of Landsat TM and SPOT (30 m and 10 m) was required to identify individual features such as windrows, etc. The utility and uniqueness of a multispectral TM signature developed lo identify spilled oil is discussed in detail with reference to direct terrestrial measurements of oil reflectance and the possibility of other sources of the signature such as ocean vegetation and direct reflectance from some beach materials. Other directly observable ocean parameters such as sea surface temperature and suspended sediment were noted and incorporated into the analysis in terms of ocean circulation and the creation of weathered spill products such as 'tar balls'. The 'mid-infrared' (TM band 5) provided the strongest component of the oil signature. However, the spill was observable in other wavelengths as well, including the thermal infrared where at various times and locations it appeared either warmer or cooler than the surrounding waters. These observations are discussed in terms of oil emissivity and reflected solar radiation.

The study which provided the basis for the development of the standards for yield grades of beef carcasses was reported by Murphey et al.(1960). The equation which was used as a basis for the yield grade standards was adpated from the regression equation, percent boneless retail cuts from round, loin, rib and chuck=51.34 −5.78 (single fat thickness over ribeye, in.) −.462 (percent kidney fat) + .740 area of ribeye, sq. in.) −.0093 (carcass wt., lb.). This equation was developed from data taken from 162 carcasses covering the full range of the quality grades (Prime to Canner) and included steers, heifers and cows. “When the U.S.D.A. equation is applied to another population of more homogeneous carcasses, one should not expect necessarily to obtain the exact relationship between estimated yield of retail cuts and actual yield of retail cuts as observed in the original U.S.D.A. study,” (Stringer et al., 1968).The objective of this study was to determine the predictive values of five carcass measurements when weight and percent retail cuts were predicted, using measurements taken from steer carcasses with a narrow range of quality grades and carcass weights.

Forty-eight average Choice and 36 average Good conformation steer carcasses were used to study the effect of carcass conformation, hot carcass weight and fat thickness at the 12th rib on yield of uniformly trimmed retail cuts.Average Choice conformation carcasses yielded a higher percent (P<.05) of total retail cuts than average Good conformation carcasses mainly due to a higher yield of minor retail cuts and less bone. There were no significant differences in percent of retail cuts from the primal wholesale cuts or percent of thick retail cuts (roasts and steaks) attributable to conformation.Hot carcass weight did not significantly affect the percent of retail cuts when conformation and fat thickness were similar.Fat thickness at the 12th rib (1.31 to 2.0 vs.0.8 to 1.3 cm.) had a more consistent effect on weight and percent retail cuts than conformation or carcass weight. Carcasses with greater fat thickness yielded less retail cuts and more fat than carcasses with less fat thickness.

Two hundred steers, progeny of 12 pure-bred beef sires, were allotted equally by sire group into five lots after being weaned and were full-fed a growing and finishing ration for 139 to 251 days. A lot of cattle was slaughtered every 28 days during this period. The right side of each carcass was processed into retail cuts.Slaughter weight and carcass weight increased as the length of time on feed increased. A slight over-all decrease in rate of gain and an over-all increase in dressing percent were associated with extended time on feed. Mean carcass quality grade by lot did not improve significantly after 195 days on feed.Significant differences in quantitative and qualitative carcass characteristics existed among progeny of the various sires. Some sire differences in percent retail yield were affected by days on feed.The most significant effect of extended feeding from 139 to 251 days was an increase in percent fat and a decrease in percent retail cuts.Steers full-fed on a finishing ration beyond average to high Good had a disadvantage in total percent retail cuts and in the percent of retail cuts from the high priced primal cuts. Percent retail cuts from progeny of most sires decreased as days on full feed increased.

Short loin steaks from 200 beef steers were evaluated to determine the effects of sire, length of feeding, and sire x length of feeding upon flavor, tenderness, and over-all desirability. The steers were the progeny of 12 beef sires, neither the steers or the sires being a random sample of the population. Lot 1 was fed 139 days and thereafter, a lot was taken off feed every 28 days; for example, lot 5 was on feed 251 days.Laboratory flavor intensity scores were affected by length of time on feed (P<.01) and by sire (P<.05). Significant (P<.01) differences in flavor desirability scores due to length of feeding and sire were observed by the laboratory panel but not by the consumer panel. Tenderness desirability scores were significantly (P<.01) affected by sire, length of time on feed, and by sire x length of time on feed in the laboratory panel. The consumer panel did not detect any significant differences in tenderness desirability (P<.05). Mean Warner-Bratzler shear values were significantly (P<.05) affected by sire and length on feed. Over-all desirability scores were significantly (P<.01) affected by sire, length of time on feed and by sire x length of time on feed in the laboratory panel. The consumer panel did not detect any significant differences in over-all desirability of the steaks.Under the conditions of this study, feeding beyond 139 days (lot 1) did not result in consistent increases or decreases in flavor intensity, flavor desirability, tenderness desirability or over-all desirability. Sire and sire length of time on feed effects upon palatability appear to be worthy of further consideration.

Thirty-one choice grade beef short loins were used to determine the effect of cooking method (broiling and cooking in deep fat), sample core size (1.27 cm. and 2.54 cm.), temperature of sample when sheared (hot and cold), and sample core position (medial, central and lateral) on Warner-Bratzler shear values. Shear values were significantly affected by all treatments. Sample cores from steaks cooked in deep fat had higher shear values than samples from broiled steaks. Sample cores sheared cold had higher shear values than sample cores sheared hot. Sample cores from the central and lateral locations had higher shear values than sample cores from the medial location. Low but significant positive relationships were observed between shear values for the various treatments employed.

Relative seed yields should be an important measure of the effects of the endophytic fungus Acremonium coenophialumMorgan‐Jones & Gams on relative fitness in tall fescue (Festuca arundinaceaSchreb.). Two field experiments were conducted on Cecil sandy‐loam soils (clayey, kaolinitic, thermic Typic Kanhapuldults) to investigate the effects of endophyte infection on seed production and associated traits. The studies used endophyte‐infected and uninfected clones of the same plant genotypes. In Exp. I and II, endophyte infection resulted in 79 and 32% more total seed by weight, 60 and 33% more seeds per plant, 20 and 34% more panicles per plant, and 32 and 4% more seeds per panicle, respectively. The 300‐seed wt. was greater for infected plants in Exp. I but not in Exp. II. Plant genotype ✕ fungal status interactions occurred for all traits except for seeds per plant and seeds per panicle in Exp. II. These interactions occurred largely because the effect of the endophyte varied from no or small increases to significant increases in trait expression for different plant genotypes. The results indicate that endophyte‐infected tall fescue plants have much higher relative fitness for seed production than uninfected plants. Populations with low fungal incidence could rapidly shift toward high levels of infestation during seed increase or in pastures when seed production is allowed, leading to establishment of volunteer plants.

Widespread infection of tall fescue (Festuca arundinaceaSchreber) by the endophytic fungus (Acremonium coenophudumMorgan‐Jones and Gams) is responsible for poor performance of grazing animals. Because infection results in changes in phenotypic means for numerous traits, changes in phenotypic variances could also be a result of infection. Phenotypic variances for forage and seed production were investigated in studies of polycross families from endophyte‐infected (El) and endophyte‐free (EF) clones of 20 tall fescue genotypes. No significant phenotypic variance for forage production was detected among El families during the study. In 1989, phenotypic variances for EF were greater than El for both harvests, suggesting that the endophyte can mask plant genotypic variance. Significant phenotypic variances were observed for all seed production traits in both El and EF. Phenotypic variances for total seed weight and seed numbers in 1990 were greater for El than for EF. Estimates of genetic variance for these traits were not greater than twice the standard error in the EF state but were greater than twice the standard error in the El state. The resulting heritability estimates reflected this difference. Endophyte presence could result in overestimates of plant genotypic variance for these traits. Breeding strategies should consider presence or absence of endophyte and the possible effects on variances.

Soil contamination of herbage samples during harvesting may inflate forage yields and render samples unfit for chemical analysis. Observations of soil in herbage samples led to these experiments to quantify soil contamination of herbage samples by various plot harvesting methods. Three harvester designs were compared: the Carter flail harvester; a Penn State‐designed flail harvester with a blower to provide lift to the forage stream; and the conventional sicklebar and rake method. Soil contamination by harvesting was determined by comparing ash content of harvested samples with that of handharvested samples. The flail harvesters resulted in considerable soil contamination of samples. The Carter harvester consistently introduced more soil (5.1 to 9.1% by weight) into the herbage than the sicklebar and rake (0.1 to 1.0% by weight). However, the flail‐with‐fan did not always exceed the sicklebar‐and‐rake in soil introduction. It appears that significant soil contamination and yield inflation is possible with flail‐type forage harvesters.

THE purpose of this communication is to show that the southern edge of the auroral belt (the latitudinal range over which aurorae occur at a given time and longitude) can be reliably tracked by radio means. With the multi-frequency high-frequency system used at College, Alaska, the auroral belt can be tracked from overhead at 65° to above 80° north latitude. This wide coverage is possible because the high-frequency system utilizes ordinary ionospheric reflexion to extend the northern limit of detection, and normal E and F layer refraction to produce perpendicularity between the wave and the geomagnetic field. The very-high-frequency auroral radar, on the other hand, can detect only those aurorally associated scatterers located in the E layer near the relatively limited region where the line of sight is normal to the geomagnetic field.