WorldWideScience

Sample records for steers grazing wet

  1. Effects of grazing system on production and parasitism of dairy breed heifers and steers grazing wet marginal grasslands

    DEFF Research Database (Denmark)

    Kristensen, Troels; Thamsborg, S.M.; Andersen, Refsgaard

    2006-01-01

    Production and endoparasitism of first grazing season Holstein heifers and steers were investigated over two grazing seasons. Studies were conducted on low-lying peaty soil. In year 2000, 40 animals were included in a 2x2 factorial, replicated experiment with two sexes (steers v. heifers) and two...

  2. supplementation of energy and/or protein to steers grazing summer ...

    African Journals Online (AJOL)

    Some aspects of the effect of supplementary energy and/or protein, strategically ptovided to steers on summer veld, were investi gated. 40 Friesland steers in the age ... was posed whether the strategic provision of energy and or protein to steers grazing .... Definitions and abbreviotions was determined after cooling for 24 h ...

  3. Effects of chicory/perennial ryegrass swards compared with perennial ryegrass swards on the performance and carcass quality of grazing beef steers.

    Directory of Open Access Journals (Sweden)

    Christina L Marley

    Full Text Available An experiment investigated whether the inclusion of chicory (Cichorium intybus in swards grazed by beef steers altered their performance, carcass characteristics or parasitism when compared to steers grazing perennial ryegrass (Lolium perenne. Triplicate 2-ha plots were established with a chicory/ryegrass mix or ryegrass control. Forty-eight Belgian Blue-cross steers were used in the first grazing season and a core group (n = 36 were retained for finishing in the second grazing season. The experiment comprised of a standardisation and measurement period. During standardisation, steers grazed a ryegrass/white clover pasture as one group. Animals were allocated to treatment on the basis of liveweight, body condition and faecal egg counts (FEC determined 7 days prior to the measurement period. The measurement period ran from 25 May until 28 September 2010 and 12 April until 11 October 2011 in the first and second grazing year. Steers were weighed every 14 days at pasture or 28 days during housing. In the first grazing year, faecal samples were collected for FEC and parasite cultures. At the end of the first grazing year, individual blood samples were taken to determine O. ostertagi antibody and plasma pepsinogen levels. During winter, animals were housed as one group and fed silage. In the second grazing year, steers were slaughtered when deemed to reach fat class 3. Data on steer performance showed no differences in daily live-weight gain which averaged 1.04 kg/day. The conformation, fat grade and killing out proportion of beef steers grazing chicory/ryegrass or ryegrass were not found to differ. No differences in FEC, O. ostertagi antibody or plasma pepsinogen levels of beef steers grazing either chicory/ryegrass or ryegrass were observed. Overall, there were no detrimental effects of including chicory in swards grazed by beef cattle on their performance, carcass characteristics or helminth parasitism, when compared with steers grazing ryegrass.

  4. Steers grazing of a rye cover crop influences growth of rye and no-till cotton

    Science.gov (United States)

    Small grain cover crops offer opportunities for grazing but effects on following row crops are not well understood. From 1999 through 2008, stocker steers sequence grazed small grains in a 2-paddock rye-cotton-wheat-fallow- rye rotation. Treatments imposed on rye included 1) zero-grazing from 1999; ...

  5. Carcass mass gains of steers grazing star grass, with different ...

    African Journals Online (AJOL)

    Carcass mass gains of steers grazing dryland Cynodon aethiopicus cv. No. 2 Star grass pastures during the growing season were determined for each of 16 treatments comprising four levels of nitrogen fertilisation in combination with four overlapping sets of stocking rates. The treatments were repeated over four growing ...

  6. Effect of yearling steer sequence grazing of perennial and annual forages in an integrated crop and livestock system on grazing performance, delayed feedlot entry, finishing performance, carcass measurements, and systems economics.

    Science.gov (United States)

    Sentürklü, Songul; Landblom, Douglas G; Maddock, Robert; Petry, Tim; Wachenheim, Cheryl J; Paisley, Steve I

    2018-06-04

    In a 2-yr study, spring-born yearling steers (n = 144), previously grown to gain <0.454 kg·steer-1·d-1, following weaning in the fall, were stratified by BW and randomly assigned to three retained ownership rearing systems (three replications) in early May. Systems were 1) feedlot (FLT), 2) steers that grazed perennial crested wheatgrass (CWG) and native range (NR) before FLT entry (PST), and 3) steers that grazed perennial CWG and NR, and then field pea-barley (PBLY) mix and unharvested corn (UC) before FLT entry (ANN). The PST and ANN steers grazed 181 d before FLT entry. During grazing, ADG of ANN steers (1.01 ± SE kg/d) and PST steers (0.77 ± SE kg/d) did not differ (P = 0.31). But even though grazing cost per steer was greater (P = 0.002) for ANN vs. PST, grazing cost per kg of gain did not differ (P = 0.82). The ANN forage treatment improved LM area (P = 0.03) and percent i.m. fat (P = 0.001). The length of the finishing period was greatest (P < 0.001) for FLT (142 d), intermediate for PST (91 d), and least for ANN (66 d). Steer starting (P = 0.015) and ending finishing BW (P = 0.022) of ANN and PST were greater than FLT steers. Total FLT BW gain was greater for FLT steers (P = 0.017), but there were no treatment differences for ADG, (P = 0.16), DMI (P = 0.21), G: F (P = 0.82), and feed cost per kg of gain (P = 0.61). However, feed cost per steer was greatest for FLT ($578.30), least for ANN ($276.12), and intermediate for PST ($381.18) (P = 0.043). There was a tendency for FLT steer HCW to be less than ANN and PST, which did not differ (P = 0.076). There was no difference between treatments for LM area (P = 0.094), backfat depth (P = 0.28), marbling score (P = 0.18), USDA yield grade (P = 0.44), and quality grade (P = 0.47). Grazing steer net return ranged from an ANN system high of $9.09/steer to a FLT control system net loss of -$298 and a PST system that was slightly less than the ANN system (-$30.10). Ten-year (2003 to 2012) hedging and net return

  7. Effects of grazing intensity on small mammal population ecology in wet meadows

    DEFF Research Database (Denmark)

    Schmidt, Niels Martin; Olsen, Henrik; Bildsøe, Mogens

    2005-01-01

    Livestock grazing is common management practice in wet grasslands. However, knowledge of its effects on small mammals is limited. We studied the influence of grazing intensity on small mammals in general and field voles Microtus agrestis in particular in two Danish wet meadows, 1998-2000. General...

  8. Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season.

    Science.gov (United States)

    Murillo, M; Herrera, E; Ruiz, O; Reyes, O; Carrete, F O; Gutierrez, H

    2016-05-01

    Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS) supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW]) were distributed randomly into 3 groups (each of 40 steers), which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May). Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size). Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G), urea-nitrogen (UN) and non-esterified fatty acids. Final BW, average daily gain (ADG) and supplement conversion (CDDGS-C) increased with increasing levels of CDDGS supplementation (p<0.05).The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05). In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg) were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW), and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI), apparent digestibility of dry matter (ADDM), crude protein (ADCP) and neutral detergent fiber (ADNDF) increased with increasing levels of CDDGS supplementation (p<0.05). The ruminal degradation rates of CP (kdCP), NDF (kdNDF) and passage rate (kp) also increased with increasing levels of CDDGS supplementation (p<0.05). Ruminal ammonia nitrogen (NH3-N) and propionate concentrations also increased with

  9. Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season

    Directory of Open Access Journals (Sweden)

    M. Murillo

    2016-05-01

    Full Text Available Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW] were distributed randomly into 3 groups (each of 40 steers, which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May. Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size. Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G, urea-nitrogen (UN and non-esterified fatty acids. Final BW, average daily gain (ADG and supplement conversion (CDDGS-C increased with increasing levels of CDDGS supplementation (p<0.05.The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05. In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW, and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI, apparent digestibility of dry matter (ADDM, crude protein (ADCP and neutral detergent fiber (ADNDF increased with increasing levels of CDDGS supplementation (p<0.05. The ruminal degradation rates of CP (kdCP, NDF (kdNDF and passage rate (kp also increased with increasing levels of CDDGS supplementation (p<0.05. Ruminal ammonia nitrogen (NH3-N and propionate concentrations also increased with

  10. Effect of Supplemental Corn Dried Distillers Grains with Solubles Fed to Beef Steers Grazing Native Rangeland during the Forage Dormant Season

    Science.gov (United States)

    Murillo, M.; Herrera, E.; Ruiz, O.; Reyes, O.; Carrete, F. O.; Gutierrez, H.

    2016-01-01

    Two experiments were conducted to evaluate the effects of the level of corn dry distillers grains with solubles (CDDGS) supplementation on growing performance, blood metabolites, digestion characteristics and ruminal fermentation patterns in steers grazing dormant forage. In Exp. 1, of growth performance, 120 steers (204±5 kg initial body weight [BW]) were distributed randomly into 3 groups (each of 40 steers), which were provided with the following levels of CDDGS supplement: 0%, 0.25%, or 0.50% BW. All groups of steers were grazed for 30 days in each of 3 grazing periods (March, April, and May). Approximately 1,000 ha of the land was divided with electric fencing into 3 equally sized pastures (333 ha in size). Blood samples were collected monthly from 20 steers in each grazing group for analysis of glucose (G), urea-nitrogen (UN) and non-esterified fatty acids. Final BW, average daily gain (ADG) and supplement conversion (CDDGS-C) increased with increasing levels of CDDGS supplementation (p<0.05).The CDDGS supplementation also increased the plasma G and UN concentrations (p<0.05). In Exp. 2, of digestive metabolism, 9 ruminally cannulated steers (BW = 350±3 kg) were distributed, following a completely randomized design, into groups of three in each pasture. The ruminally cannulated steers were provided the same levels of CDDGS supplementation as in the growing performance study (0%, 0.25%, and 0.50% BW), and they grazed along with the other 40 steers throughout the grazing periods. The dry matter intake, crude protein intake, neutral detergent fiber intake (NDFI), apparent digestibility of dry matter (ADDM), crude protein (ADCP) and neutral detergent fiber (ADNDF) increased with increasing levels of CDDGS supplementation (p<0.05). The ruminal degradation rates of CP (kdCP), NDF (kdNDF) and passage rate (kp) also increased with increasing levels of CDDGS supplementation (p<0.05). Ruminal ammonia nitrogen (NH3-N) and propionate concentrations also increased with

  11. Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

    Directory of Open Access Journals (Sweden)

    Roberta Carrilho Canesin

    2014-04-01

    Full Text Available Reduced supplementation frequency is a broadly applied management practice. Ruminants consuming low quality forages/pastures, supplemented less than once daily are able to maintain body weight gain (BWG, efficiency of use of dry matter, nitrogen and other nutrients, as compared with animals supplemented once daily. We evaluated the feeding behavior, dry matter intake (DMI, dry matter and organic matter digestibility (DMD and OMD, BWG, Longissimus muscle area and backfat depth of Nellore steers raised on Brachiaria brizantha cv. Marandu pastures during the dry season, with different supplementation patterns. Thirty six animals (338 ± 40.7 kg were distributed over nine paddocks according to a completely randomized design. Treatments were based on supplementation frequency: once daily (OD, once daily except Saturdays and Sundays (SS, or on alternate days (AD, at 1.0 %, 1.4 % and 2.0 % BW, respectively. Average total DMI accounted for 1.6 % BW day-1, with no effect of supplementation frequency. Supplementation frequency had no effect on BWG or grazing time during the day. There was no difference in Longissimus muscle area animals supplemented daily, SS and AD. The backfat depth was thinner in animals supplemented AD, but even in this case, it was within the standards considered satisfactory for a finishing steer. Reducing supplementation frequency seems a good option to lower labor costs without affecting feed efficiency or carcass quality in beef cattle grazing tropical pastures.

  12. Effect of corn dry distiller grains plus solubles supplementation level on performance and digestion characteristics of steers grazing native range during forage growing season.

    Science.gov (United States)

    Martínez-Pérez, M F; Calderón-Mendoza, D; Islas, A; Encinias, A M; Loya-Olguín, F; Soto-Navarro, S A

    2013-03-01

    Two experiments were conducted to evaluate effects of corn dry distiller grains plus condensed solubles (DDGS) supplementation level on performance digestion characteristics of steers grazing native range during the forage growing season. In the performance study, 72 (206 ± 23.6 kg; 2008) and 60 (230 ± 11.3 kg; 2009) English crossbred steer calves were used in a randomized complete block design replicated over 2 yr. The grazing periods lasted 56 and 58 d and started on August 11 and 18 for 2008 and 2009, respectively. Each year, steers were blocked by BW (light, medium, and heavy), stratified by BW within blocks, and randomly assigned to 1 of 4 grazing groups. Each grazing group (6 steers in 2008 and 5 in 2009) was assigned to a DDGS supplementation levels (0, 0.2, 0.4, and 0.6% BW). Grazing group served as the experimental unit with 12 groups per year receiving 1 of 4 treatments for 2 yr (n = 6). In the metabolism study, 16 English crossbred steers (360 ± 28.9 kg) fitted with ruminal cannulas grazing native range during the summer growing season were used in a completely randomized design to evaluate treatment effects on forage intake and digestion. The experiment was conducted during the first and second weeks of October 2008. Steers were randomly assigned to supplement level (0, 0.2, 0.4, and 0.6% BW; n = 4) and grazed a single native range pasture with supplements offered individually once daily at 0700 h. In the performance study, ADG (0.64, 0.75, 0.80, and 0.86 ± 0.03 kg/d for 0, 0.2, 0.4, and 0.6% BW, respectively) increased linearly (P = 0.01) with increasing DDGS supplementation level. In the metabolism study, forage OM, NDF, CP, and ether extract (EE) intake decreased (P ≤ 0.05) linearly with increasing DDGS supplementation level. Total CP and EE intake increased (P ≤ 0.002) with increasing DDGS supplementation level. Digestibility of OM, NDF, and EE increased (linear; P ≤ 0.008) whereas the soluble CP fraction of forage masticate sample

  13. Longitudinal shifts in bacterial diversity and fermentation pattern in the rumen of steers grazing wheat pasture.

    Science.gov (United States)

    Pitta, D W; Pinchak, W E; Dowd, S; Dorton, K; Yoon, I; Min, B R; Fulford, J D; Wickersham, T A; Malinowski, D P

    2014-12-01

    Grazing steers on winter wheat forage is routinely practiced in the Southern Great Plains of the US. Here, we investigated the dynamics in bacterial populations of both solid and liquid ruminal fractions of steers grazing on maturing wheat forage of changing nutritive quality. The relationship between bacterial diversity and fermentation parameters in the liquid fraction was also investigated. During the first 28 days, the wheat was in a vegetative phase with a relatively high crude protein content (CP; 21%), which led to the incidence of mild cases of frothy bloat among steers. Rumen samples were collected on days 14, 28, 56 and 76, separated into solid and liquid fractions and analyzed for bacterial diversity using 16S pyrotag technology. The predominant phyla identified were Bacteroidetes (59-77%) and Firmicutes (20-33%) across both ruminal fractions. Very few differences were observed in the rumen bacterial communities within solid and liquid fractions on day 14. However, by day 28, the relatively high CP content complemented a distinct bacterial and chemical composition of the rumen fluid that was characterized by a higher ratio (4:1) of Bacteroidetes:Firmicutes and a corresponding lower acetate:propionate (3:1) ratio. Further, a greater accumulation of biofilm (mucopolysaccharide complex) on day 28 was strongly associated with the abundance of Firmicutes lineages such as Clostridium, Ruminococcus, Oscillospira and Moryella (Prumen microbiome and their association with fermentation activity in the rumen of steers during the vegetative (bloat-prone) and reproductive stages of wheat forage. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. In vitro bacterial growth and in vivo ruminal microbiota populations associated with bloat in steers grazing wheat forage.

    Science.gov (United States)

    Min, B R; Pinchak, W E; Anderson, R C; Hume, M E

    2006-10-01

    The role of ruminal bacteria in the frothy bloat complex common to cattle grazing winter wheat has not been previously determined. Two experiments, one in vitro and another in vivo, were designed to elucidate the effects of fresh wheat forage on bacterial growth, biofilm complexes, rumen fermentation end products, rumen bacterial diversity, and bloat potential. In Exp. 1, 6 strains of ruminal bacteria (Streptococcus bovis strain 26, Prevotella ruminicola strain 23, Eubacterium ruminantium B1C23, Ruminococcus albus SY3, Fibrobacter succinogenes ssp. S85, and Ruminococcus flavefaciens C94) were used in vitro to determine the effect of soluble plant protein from winter wheat forage on specific bacterial growth rate, biofilm complexes, VFA, and ruminal H2 and CH4 in mono or coculture with Methanobrevibacter smithii. The specific growth rate in plant protein medium containing soluble plant protein (3.27% nitrogen) was measured during a 24-h incubation at 39 degrees C in Hungate tubes under a CO2 gas phase. A monoculture of M. smithii was grown similarly, except under H2:CO2 (1:1), in a basal methanogen growth medium supplemented likewise with soluble plant protein. In Exp. 2, 6 ruminally cannulated steers grazing wheat forage were used to evaluate the influence of bloat on the production of biofilm complexes, ruminal microbial biodiversity patterns, and ruminal fluid protein fractions. In Exp. 1, cultures of R. albus (P bloated than for nonbloated steers when grazing wheat forage. The molecular analysis of the 16S rDNA showed that 2 different ruminal microbiota populations developed between bloated and nonbloated animals grazing wheat forage. Bloat in cattle grazing wheat pastures may be caused by increased production of biofilm, resulting from a diet-influenced switch in the rumen bacterial population.

  15. Ingestive behavior of grazing steers fed increasing levels of concentrate supplementation with different crude protein contents.

    Science.gov (United States)

    Mendes, Fabrício Bacelar Lima; Silva, Robério Rodrigues; de Carvalho, Gleidson Giordano Pinto; da Silva, Fabiano Ferreira; Lins, Túlio Otávio Jardim D Almeida; da Silva, Anderson Luiz Nascimento; Macedo, Venício; Abreu Filho, George; de Souza, Sinvaldo Oliveira; Guimarães, Joanderson Oliveira

    2015-02-01

    This study aimed to evaluate the ingestive behavior of steers on Brachiaria brizantha pasture fed diets with increasing levels of concentrate supplementation. Thirty-two crossbred steers in the finishing phase with average weight of 420 ± 8 kg were distributed in a completely randomized design with four treatments and eight replicates per treatment. Their behavior was assessed every 5 min for 24 h, in the middle of the experimental period. Variance and regression analyses at 0.05 % probability were adopted. The times spent grazing and ruminating reduced linearly (P <0.05), whereas the times spent at the trough (eating) and on other activities increased linearly (P <0.05) as the supplementation levels were elevated. The total feeding and chewing times decreased linearly (P <0.05) as the concentrate levels in the diet were elevated. By increasing the supplementation levels, the number of bites per day decreased linearly (P <0.05), and the feed efficiency of dry matter increased quadratically. Rumination efficiency of dry matter increased linearly (P <0.05) with increasing levels of concentrate supplementation. Grazing and rumination activities are reduced when the time devoted to other activities and at the trough are increased, as a result of the substitution effect.

  16. Ganho de peso vivo e fermentação ruminal em novilhos mantidos em pastagem cultivada de clima temperado e recebendo diferentes suplementos Live weight gain and ruminal fermentation by steers grazing cool-season grass pasture and given different supplements

    Directory of Open Access Journals (Sweden)

    Magali Floriano da Silveira

    2006-06-01

    Full Text Available Foram conduzidos dois experimentos para avaliar o ganho de peso vivo (Experimento 1 e parâmetros da fermentação ruminal (Experimento 2 em quarenta novilhos cruzados Charolês e Nelore, mantidos em pastagem cultivada de inverno, por quatro horas diárias e não suplementados, ou por somente duas horas, mas suplementados (1% do peso vivo com silagem de planta inteira, silagem de grão úmido ou com grão seco de sorgo. Os animais alimentados somente com pastagem obtiveram os maiores ganhos de peso vivo (P0,05 pela suplementação, as de amônia e açúcares foram maiores nos animais mantidos somente com pastagem e nos suplementados com silagem de grão úmido, e menores nos animais suplementados com silagem de planta inteira ou com grão seco de sorgo (PTwo experiments to evaluate daily weight gain (Experiment 1 and ruminal fermentation parameters (Experiment 2 were carried out. Nelore and Charolais crossbreed steers grazing on cool-season pasture during four hours daily or during only two hours daily but supplemented (1% of live weight with sorghum whole plant silage, wet grain silage or dry grain were used. Animals fed only with pasture obtained the highest and, those supplemented with whole plant silage, the lowest daily weight gain (P0.05 by supplementation. Ammonia and sugar concentrations were higher by animals fed only with pasture or supplemented with sorghum wet grain silage and lower by those supplemented with whole plant silage or dry grain (P<0.05. Ruminal pH values were lower by animals supplemented with sorghum wet grain silage (P<0.05. Supplements did not improve weight gain of steers grazing cool-season pasture but ruminal fermentation varied through a day and was different among supplements. Results also indicate that, besides supplement type, synchrony between grazing and supplementation schedule may represent a conditioning factor to improve feed efficiency use by animals.

  17. Impact of grazing dairy steers on winter rye (Secale cereale versus winter wheat (Triticum aestivum and effects on meat quality, fatty acid and amino acid profiles, and consumer acceptability of organic beef.

    Directory of Open Access Journals (Sweden)

    Hannah N Phillips

    Full Text Available Meat from Holstein and crossbred organic dairy steers finished on winter rye and winter wheat pastures was evaluated and compared for meat quality, fatty acid and amino acid profiles, and consumer acceptability. Two adjacent 4-ha plots were established with winter rye or winter wheat cover crops in September 2015 at the University of Minnesota West Central Research and Outreach Center (Morris, MN. During spring of 2015, 30 steers were assigned to one of three replicate breed groups at birth. Breed groups were comprised of: Holstein (HOL; n = 10, crossbreds comprised of Montbéliarde, Viking Red, and HOL (MVH; n = 10, and crossbreds comprised of Normande, Jersey, and Viking Red (NJV; n = 10. Dairy steers were maintained in their respective replicate breed group from three days of age until harvest. After weaning, steers were fed an organic total mixed ration of organic corn silage, alfalfa silage, corn, soybean meal, and minerals until spring 2016. Breed groups were randomly assigned to winter rye or winter wheat and rotationally grazed from spring until early summer of 2016. For statistical analysis, independent variables were fixed effects of breed, forage, and the interaction of breed and forage, with replicated group as a random effect. Specific contrast statements were used to compare HOL versus crossbred steers. Fat from crossbreds had 13% greater omega-3 fatty acids than HOL steers. Furthermore, the omega-6/3 ratio was 14% lower in fat from crossbreds than HOL steers. For consumer acceptability, steaks from steers grazed on winter wheat had greater overall liking than steers grazed on winter rye. Steak from crossbreeds had greater overall liking than HOL steers. The results suggest improvement in fatty acids and sensory attributes of beef from crossbred dairy steers compared to HOL steers, as well as those finished on winter wheat compared to winter rye.

  18. Impact of grazing dairy steers on winter rye (Secale cereale) versus winter wheat (Triticum aestivum) and effects on meat quality, fatty acid and amino acid profiles, and consumer acceptability of organic beef.

    Science.gov (United States)

    Phillips, Hannah N; Heins, Bradley J; Delate, Kathleen; Turnbull, Robert

    2017-01-01

    Meat from Holstein and crossbred organic dairy steers finished on winter rye and winter wheat pastures was evaluated and compared for meat quality, fatty acid and amino acid profiles, and consumer acceptability. Two adjacent 4-ha plots were established with winter rye or winter wheat cover crops in September 2015 at the University of Minnesota West Central Research and Outreach Center (Morris, MN). During spring of 2015, 30 steers were assigned to one of three replicate breed groups at birth. Breed groups were comprised of: Holstein (HOL; n = 10), crossbreds comprised of Montbéliarde, Viking Red, and HOL (MVH; n = 10), and crossbreds comprised of Normande, Jersey, and Viking Red (NJV; n = 10). Dairy steers were maintained in their respective replicate breed group from three days of age until harvest. After weaning, steers were fed an organic total mixed ration of organic corn silage, alfalfa silage, corn, soybean meal, and minerals until spring 2016. Breed groups were randomly assigned to winter rye or winter wheat and rotationally grazed from spring until early summer of 2016. For statistical analysis, independent variables were fixed effects of breed, forage, and the interaction of breed and forage, with replicated group as a random effect. Specific contrast statements were used to compare HOL versus crossbred steers. Fat from crossbreds had 13% greater omega-3 fatty acids than HOL steers. Furthermore, the omega-6/3 ratio was 14% lower in fat from crossbreds than HOL steers. For consumer acceptability, steaks from steers grazed on winter wheat had greater overall liking than steers grazed on winter rye. Steak from crossbreeds had greater overall liking than HOL steers. The results suggest improvement in fatty acids and sensory attributes of beef from crossbred dairy steers compared to HOL steers, as well as those finished on winter wheat compared to winter rye.

  19. Effects of sorghum wet distillers grains plus solubles in steam-flaked corn-based finishing diets on steer performance, carcass characteristics, and digestibility characteristics

    Science.gov (United States)

    Two studies were conducted to evaluate the effects of sorghum wet distillers grains (SWDGS) in finishing diets on steer performance, carcass characteristics, and nutrient digestibility. In Exp. 1, 240 steers (initial BW = 379 +/-1 kg) were fed steam-flaked corn (SFC)-based diets with or without 25%...

  20. Effects of condensed tannins supplementation level on weight gain and in vitro and in vivo bloat precursors in steers grazing winter wheat.

    Science.gov (United States)

    Min, B R; Pinchak, W E; Anderson, R C; Fulford, J D; Puchala, R

    2006-09-01

    Research was conducted to determine the effects of level of supplementation with quebracho condensed tannins (CT) on in vitro ruminal fluid gas production, in vivo ruminal fluid protein fractions, bloat dynamics, and ADG of steers grazing winter wheat. Two experiments were conducted to 1) enumerate the effect of ruminal fluid from steers fed quebracho CT (0, 1, and 2% CT/kg of DMI) on in vitro gas and methane production from minced fresh wheat forage; and 2) quantify the influence of CT supplementation on ruminal protein characteristics, biofilm complexes, bloat potential, and ADG of steers grazing wheat pasture. Eighteen ruminally cannulated steers (386 +/- 36 kg of BW) were randomly allocated to 1 of 3 treatments that included a control (water infusion) and 2 CT treatment levels (1 or 2% CT/kg of DMI). Treatments were administered daily (63 d) through the rumen cannula as pre-mixes with warm water (approximately 30 degrees C). Rumen contents were collected 2 h postinfusion (at 1030 to 1130) on d 0, 20, 40, 50, and 60. Bloat was visually scored daily for 5 d each wk. In Exp. 1, supplementation of CT decreased the rate of in vitro gas production in a dose-dependent response. In Exp. 2, ADG increased (P bloat score across stage of growth and replicates decreased linearly with increasing CT supplementation; bloat scores were greater (P rumen fluid protein fractions varied among CT treatments and stage of growth. Addition of CT reduced the severity of bloat, principally through reducing microbial activities, biofilm production, and ruminal gas production. Quebracho CT is potentially a value-added supplement that can decrease the impacts of frothy bloat and increase BW gains in stocker cattle-wheat systems.

  1. Individual intake and antiparasitic efficacy of free choice mineral containing fenbendazole for grazing steers.

    Science.gov (United States)

    Garossino, K C; Ralston, B J; Olson, M E; McAllister, T A; Milligan, D N; Genswein, B M A

    2005-04-20

    A 95-day study (June 25-September 27, 2001) was conducted using 120 steers (311.9+/-2.4 kg) randomly allocated to two treatments: (1) mineral containing 0.55% fenbendazole (FBZ) and (2) control, no FBZ in the mineral. Animals in the FBZ group were individually identified by an electronic tag that was read each time an animal attended the mineral feeder. The feeder was equipped with load cells that enabled individual mineral intakes to be estimated. The FBZ group was provided with non-medicated mineral during a 14-day adaptation period (July 23-August 5) and an 8-day post-medication period (September 17-24). The intake of FBZ was monitored for 14 days during each of the two treatment periods; August 6-19 and September 3-16, separated by a 14-day non-medicated period, August 20-September 2. Control animals had access to non-medicated mineral for the entire 95-day study period. All steers were grazed on alfalfa-grass pasture for the duration of the study and had free access to flocculated, filtered and chlorinated water via an automatic waterer. Fecal samples were collected from steers three times during the experiment July 23, August 27 and September 27, and analyzed for nematode eggs and Giardia sp. cysts. Seventy-five and 83% of the steers in the FBZ group visited the mineral feeder during the first and second treatment periods, respectively. Individual daily mineral and FBZ intake for the first and second treatment periods was 52.9+/-6.6g per day and 10.1+/-1.2mg/kg BW; 72.3+/-8.4 g per day and 11.8+/-1.4 mg/kg BW, respectively. FBZ animals were separated into three groups during each treatment period based on the recommended dose (RD) of FBZ (5 mg/kg/BW), those that received > the RD, those that received 50% RD and those that received 0.05) by FBZ as compared to controls in either treatment period. These results may be a reflection of Giardia re-infection occurring following treatment and highlight the need for variation in treatment regimes specifically targeted

  2. Dietary selection by steers grazing kikuyu

    African Journals Online (AJOL)

    being grazeA for a period of 3,5 days in a four-week rotation, at ... Cattle improve the quality of their diet by actively seeking ... of stem in their diet. This would explain why the stem fraction mad~ no significant contribution to the equation predicting diet~ry selection. A:1unusual fact which emerged is that the animals selected.

  3. Day and night grazing by cattle in the Sahel

    NARCIS (Netherlands)

    Ayantunde, A.A.; Fernandez-Rivera, S.; Hiernaux, P.H.; Keulen, van H.; Udo, H.M.J.

    2002-01-01

    The influence of night grazing on feeding behavior, nutrition and performance of cattle was studied. Twenty-four steers weighing 367 kg (SD = 76) grazed either from 0900 to 1900 (day grazers), 2100 to 0700 (night grazers) or 0900 to 1900 and 2400 to 0400 (day-and-night grazers) during 13 weeks. Four

  4. Growth, carcass characteristics, and profitability of organic versus conventional dairy beef steers.

    Science.gov (United States)

    Bjorklund, E A; Heins, B J; Dicostanzo, A; Chester-Jones, H

    2014-03-01

    Bull calves (n=49), born at the University of Minnesota West Central Research and Outreach Center (Morris) between March and May 2011, were used to compare growth measurements and profitability of conventional and organic dairy steers. Calves were assigned to 1 of 3 replicated groups at birth: conventional (CONV; n=16), organic (pasture and concentrate; ORG; n=16), or organic grass only (GRS; n=17), and analysis of variables was on a pen basis. Breed groups of calves were Holstein (HO; n=9); Holsteins (n=11) maintained at 1964 breed average level; crossbreds (n=19) including combinations of HO, Montbéliarde, and Swedish Red; and crossbreds (n=10) including combinations of HO, Jersey, Swedish Red, and Normande. The CONV steers were fed a diet of 80% concentrate and 20% forage. The ORG steers were fed a diet of organic corn, organic corn silage, and at least 30% of their diet consisted of organic pasture during the grazing season. The GRS steers grazed pasture during the grazing season and were fed high-quality hay or hay silage during the nongrazing season. Intakes of a total mixed ration were recorded daily with herd management software. A profit function was defined to include revenues and expenses for beef value, feed intake, pasture intake, health cost, and yardage. The GRS (358.6 kg) steers had lesser total gains from birth to slaughter than ORG (429.6 kg) and CONV (534.5 kg) steers. Furthermore, the GRS (0.61 kg/d) steers had lesser average daily gain from birth compared with ORG (0.81 kg/d) and CONV (1.1 kg/d) steers. The GRS and ORG steers had smaller rib eye area (49.5 and 65.8 cm(2), respectively) compared with CONV (75.4 cm(2)) steers. For profitability, GRS steers had 43% greater profit than CONV steers due to organic beef price premiums and lower feed costs. On the other hand, ORG steers had substantially less profit than CONV steers. The higher cost of production for the ORG steers is due to the extreme high value of organic corn. The results of the

  5. Summer-long grazing of high versus low endophyte (Neotyphodium coenophialum-infected tall fescue by growing beef steers results in distinct temporal blood analyte response patterns, with poor correlation to serum prolactin levels

    Directory of Open Access Journals (Sweden)

    Joshua J. Jackson

    2015-12-01

    Full Text Available Previously, we reported the effects of fescue toxicosis on developing Angus-cross steer growth, carcass, hepatic mRNA and protein expression profiles of selected serum proteins, and blood clinical and chemical profiles, after summer-long grazing (85 d of high (HE- vs low (LE-endophyte-infected fescue pastures. We now report the temporal development of acute, intermediate, and chronic responses of biochemical and clinical blood analytes determined at specified time intervals (period 1, d 0 to 36; period 2, d 37 to 58; and period 3, d 59 to 85. Throughout the trial, the alkaloid concentrations of the HE forage was consistently 19 to 25 times greater (P < 0.049 the concentration in the LE forage, and HE vs LE steers had continuously lower (P < 0.049 serum prolactin (85%, cholesterol (27%, and albumin (5%, but greater red blood cells (7%. The HE steers had decreased (P = 0.003 ADG only during period 1 (-0.05 vs 0.4 kg/d. For period 1, HE steers had reduced (P < 0.090 numbers of eosinophils (55% and lymphocytes (18%, serum triglyceride (27%, and an albumin/globulin ratio (9%, but an increased bilirubin concentration (20%. During period 2, serum LDH activities were 18% lower (P = 0.022 for HE vs LE steers. During period 3, serum levels of ALP (32%, ALT (16%, AST (15%, creatine kinase (35%, glucose (10%, and LDH (23% were lower (P < 0.040 for HE steers. Correlation analysis of serum prolactin and other blood analytes revealed that triglycerides (P = 0.042 and creatinine (P = 0.021 were moderately correlated (r < 0.433 with HE serum prolactin. In conclusion, three HE-induced blood analyte response patterns were identified: continually altered, initially altered and subsequently recovered, or altered only after long-term exposure. Blood analytes affected by length of grazing HE vs LE forages were either not, or poorly, correlated with serum prolactin. These data reveal important, temporal, data about how young cattle respond to the challenge of consuming

  6. Metagenomic Analysis of the Rumen Microbiome of Steers with Wheat-Induced Frothy Bloat

    OpenAIRE

    Pitta, D. W.; Pinchak, W. E.; Indugu, N.; Vecchiarelli, B.; Sinha, R.; Fulford, J. D.

    2016-01-01

    Frothy bloat is a serious metabolic disorder that affects stocker cattle grazing hard red winter wheat forage in the Southern Great Plains causing reduced performance, morbidity, and mortality. We hypothesize that a microbial dysbiosis develops in the rumen microbiome of stocker cattle when grazing on high quality winter wheat pasture that predisposes them to frothy bloat risk. In this study, rumen contents were harvested from six cannulated steers grazing hard red winter wheat (three with bl...

  7. Herbage intake and animal performance of cattle grazing dwarf elaphant grass with two access times to a forage peanut area

    Directory of Open Access Journals (Sweden)

    Diego Melo de Liz

    2014-12-01

    Full Text Available Relatively short grazing periods in a pure legume pasture can be an alternative for increasing animal performance in medium-quality tropical pastures. Thus, the aim was to evaluate the herbage intake and animal performance of steers grazing dwarf elephant grass (Pennisetum purpureum Schum. cv. BRS Kurumi with two access times [2 h (07:00 - 9:00 and 6 h (07:00 - 13:00] to an area of forage peanut (Arachis pintoi cv. Amarillo. Twelve steers (219 ± 28.8 kg LW were divided into four groups and assessed during three consecutive grazing cycles, from January to March 2013. The crude protein and neutral detergent fiber contents were 158 and 577 g/kg dry matter (DM for dwarf elephant grass and 209 and 435 g/kg DM for forage peanut, respectively. The pre-grazing height and leaf mass of dwarf elephant grass and forage peanut were 94 cm and 2782 kg DM/ha and 15 cm and 1751 kg DM/ha, respectively. The herbage intake (mean = 2.7 ± 0.06% LW and average daily weight gain (mean = 1.16 ± 0.31 kg/day were similar for both treatments. However, animals with 2-h access to the legume paddock grazed for 71% of the time, whereas those with 6-h access grazed for 48% of the time. The performance of the steers that were allowed to graze forage peanut pasture for 2 h is similar to that of those that were allowed to graze the legume pasture for 6 h.

  8. Performance and Grazing Pattern of West African Dwarf Sheep to ...

    African Journals Online (AJOL)

    Sixty (60) West African Dwarf sheep managed semi intensively and grazing on natural pastures were used in a study to determine the performance and grazing pattern to seasonal forage supply and quality. The animals were allowed to graze for about 6 hours daily for four months each in the dry and wet seasons, ...

  9. The Effects of Timing of Grazing on Plant and Arthropod Communities in High-Elevation Grasslands

    Science.gov (United States)

    Davis, Stacy C.; Burkle, Laura A.; Cross, Wyatt F.; Cutting, Kyle A.

    2014-01-01

    Livestock grazing can be used as a key management tool for maintaining healthy ecosystems. However, the effectiveness of using grazing to modify habitat for species of conservation concern depends on how the grazing regime is implemented. Timing of grazing is one grazing regime component that is less understood than grazing intensity and grazer identity, but is predicted to have important implications for plant and higher trophic level responses. We experimentally assessed how timing of cattle grazing affected plant and arthropod communities in high-elevation grasslands of southwest Montana to better evaluate its use as a tool for multi-trophic level management. We manipulated timing of grazing, with one grazing treatment beginning in mid-June and the other in mid-July, in two experiments conducted in different grassland habitat types (i.e., wet meadow and upland) in 2011 and 2012. In the upland grassland experiment, we found that both early and late grazing treatments reduced forb biomass, whereas graminoid biomass was only reduced with late grazing. Grazing earlier in the growing season versus later did not result in greater recovery of graminoid or forb biomass as expected. In addition, the density of the most ubiquitous grassland arthropod order (Hemiptera) was reduced by both grazing treatments in upland grasslands. A comparison of end-of-season plant responses to grazing in upland versus wet meadow grasslands revealed that grazing reduced graminoid biomass in the wet meadow and forb biomass in the upland, irrespective of timing of grazing. Both grazing treatments also reduced end-of-season total arthropod and Hemiptera densities and Hemiptera biomass in both grassland habitat types. Our results indicate that both early and late season herbivory affect many plant and arthropod characteristics in a similar manner, but grazing earlier may negatively impact species of conservation concern requiring forage earlier in the growing season. PMID:25338008

  10. Traditional cattle grazing in a mosaic alkali landscape: effects on grassland biodiversity along a moisture gradient.

    Directory of Open Access Journals (Sweden)

    Péter Török

    Full Text Available Extensively managed pastures are of crucial importance in sustaining biodiversity both in local- and landscape-level. Thus, re-introduction of traditional grazing management is a crucial issue in grassland conservation actions worldwide. Traditional grazing with robust cattle breeds in low stocking rates is considered to be especially useful to mimic natural grazing regimes, but well documented case-studies are surprisingly rare on this topic. Our goal was to evaluate the effectiveness of traditional Hungarian Grey cattle grazing as a conservation action in a mosaic alkali landscape. We asked the following questions: (i How does cattle grazing affect species composition and diversity of the grasslands? (ii What are the effects of grazing on short-lived and perennial noxious species? (iii Are there distinct effects of grazing in dry-, mesophilous- and wet grassland types? Vegetation of fenced and grazed plots in a 200-ha sized habitat complex (secondary dry grasslands and pristine mesophilous- and wet alkali grasslands was sampled from 2006-2009 in East-Hungary. We found higher diversity scores in grazed plots compared to fenced ones in mesophilous- and wet grasslands. Higher cover of noxious species was typical in fenced plots compared to their grazed counterparts in the last year in every studied grassland type. We found an increasing effect of grazing from the dry- towards the wet grassland types. The year-to-year differences also followed similar pattern: the site-dependent effects were the lowest in the dry grassland and an increasing effect was detected along the moisture gradient. We found that extensive Hungarian Grey cattle grazing is an effective tool to suppress noxious species and to create a mosaic vegetation structure, which enables to maintain high species richness in the landscape. Hungarian Grey cattle can feed in open habitats along long moisture gradient, thus in highly mosaic landscapes this breed can be the most suitable

  11. Consumo e tempo diário de pastejo por novilhos Nelore em pastagem de capim-tanzânia sob diferentes ofertas de forragem Effects of herbage allowance on the intake and grazing time of Nellore steers grazing tanzâniagrass pasture

    Directory of Open Access Journals (Sweden)

    Miguel Marques Gontijo Neto

    2006-02-01

    Full Text Available Os efeitos de diferentes níveis de oferta de forragem, associados a alterações no dossel induzidas pelo pastejo, sobre o tempo de pastejo e o consumo de forragem por novilhos mantidos em pastagem de capim-tanzânia foram avaliados neste experimento. Os quatro níveis planejados de oferta de forragem (OF (kg de MS de lâmina foliar/100 kg de PV animal/dia, % resultaram em OF de 6,1 ± 0,59; 11,1 ± 0,77; 18,0 ± 1,24; e 23,9 ± 1,15%. Cada piquete foi pastejado por oito animais Nelore, com peso médio de 229,0 e 249,5 kg, para o primeiro e segundo períodos de amostragem, respectivamente. Foi utilizado um delineamento em blocos casualizados com quatro tratamentos, definidos pelos níveis médios de oferta de forragem. O tempo de pastejo, a disponibilidade de matéria seca de folhas, a relação folha/colmo e a altura do dossel apresentaram alta correlação com o consumo de forragem e podem ser utilizados no desenvolvimento de modelos de predição de consumo de forragem ou desempenho animal em pastejo. Estudos avaliando consumo e desempenho de animais em pastejo em relação a ofertas de forragem necessitam de descrições das disponibilidades e condições estruturais da pastagem para interpretação e comparação de resultados. Alteraçõses nas OF de capim-tanzânia, associadas àquelas nas condições estruturais da pastagem induzidas pelo pastejo tiveram efeito quadrático sobre o tempo diário de pastejo e o consumo de forragem de novilhos Nelore. O menor tempo de pastejo e o maior consumo de forragem foram verificados no nível de OF próximo a 22,5 kg de lâminas foliares/100 kg PV, que corresponde a um resíduo pós-pastejo em torno de 4.323,2 kg/ha de MS, 2.887,6 kg/ha de matéria verde seca e altura média do dossel de 64 cm.This work aimed to evaluate the effects of forage allowances on canopy changes, the grazing time and forage intake by steers grazing tanzaniagrass (Panicum maximum Jacq. pasture. The four levels of herbage

  12. Grazing alters net ecosystem C fluxes and the global warming potential of a subtropical pasture.

    Science.gov (United States)

    Gomez-Casanovas, Nuria; DeLucia, Nicholas J; Bernacchi, Carl J; Boughton, Elizabeth H; Sparks, Jed P; Chamberlain, Samuel D; DeLucia, Evan H

    2018-03-01

    The impact of grazing on C fluxes from pastures in subtropical and tropical regions and on the environment is uncertain, although these systems account for a substantial portion of global C storage. We investigated how cattle grazing influences net ecosystem CO 2 and CH 4 exchange in subtropical pastures using the eddy covariance technique. Measurements were made over several wet-dry seasonal cycles in a grazed pasture, and in an adjacent pasture during the first three years of grazer exclusion. Grazing increased soil wetness but did not affect soil temperature. By removing aboveground biomass, grazing decreased ecosystem respiration (R eco ) and gross primary productivity (GPP). As the decrease in R eco was larger than the reduction in GPP, grazing consistently increased the net CO 2 sink strength of subtropical pastures (55, 219 and 187 more C/m 2 in 2013, 2014, and 2015). Enteric ruminant fermentation and increased soil wetness due to grazers, increased total net ecosystem CH 4 emissions in grazed relative to ungrazed pasture (27-80%). Unlike temperate, arid, and semiarid pastures, where differences in CH 4 emissions between grazed and ungrazed pastures are mainly driven by enteric ruminant fermentation, our results showed that the effect of grazing on soil CH 4 emissions can be greater than CH 4 produced by cattle. Thus, our results suggest that the interactions between grazers and soil hydrology affecting soil CH 4 emissions play an important role in determining the environmental impacts of this management practice in a subtropical pasture. Although grazing increased total net ecosystem CH 4 emissions and removed aboveground biomass, it increased the net storage of C and decreased the global warming potential associated with C fluxes of pasture by increasing its net CO 2 sink strength. © 2017 by the Ecological Society of America.

  13. Characteristics of Wet and Dried Distillers Grains on Ruminal Fermentation and Effects of Dietary Wet Distillers Grains on Performance of Hanwoo Steers

    Directory of Open Access Journals (Sweden)

    Ill Young Kim

    2015-05-01

    Full Text Available Two experiments were conducted to evaluate the nutrient composition, in vitro dry matter disappearance (IVDMD and organic matter disappearance (IVOMD of three kinds of distillers grains (DG; i wet distillers grains (WDG, KRW 25/kg, ii dried distillers grains (DDG, KRW 280/kg, iii dried distillers grains with solubles (DDGS, KRW 270/kg produced from tapioca 70% and rice 30%, and to evaluate dietary effects of WDG on the performance of Hanwoo steers. In Exp. 1, twelve-WDG, four-DDG and one-DDGS were collected from seven ethanol plants. Average crude protein, crude fiber, neutral detergent fiber, and acid detergent fiber of WDG, DDG, and DDGS were: 32.6%, 17.8%, 57.5%, and 30.2% for WDG, 36.7%, 13.9%, 51.4%, and 30.5% for DDG, and 31.0%, 11.9%, 40.3%, and 21.2% for DDGS (DM basis, respectively. The DDGS had a higher quantity of water-soluble fraction than WDG and DDG and showed the highest IVDMD (p<0.05 in comparison to others during the whole experimental time. The IVDMD at 0 to 12 h incubation were higher (p<0.05 in DDG than WDG, but did not show significant differences from 24 to 72 h. The same tendency was observed in IVOMD, showing that DG made from tapioca and rice (7:3 can be used as a feed ingredient for ruminants. Considering the price, WDG is a more useful feed ingredient than DDG and DDGS. In Exp. 2, 36 Hanwoo steers of 21 months (495.1±91 kg were randomly assigned to one of three dietary treatments for 85 days; i Control (total mixed ration, TMR, ii WDG 10% (TMR containing 10% of WDG, as fed basis, and iii WDG 20% (TMR containing 20% of WDG, as fed basis. With respect to body weight and average daily gain, there were no differences between control and WDG treatments during the whole experimental period. Dry matter intake of control (9.34 kg, WDG 10% (9.21 kg and 20% (8.86 kg and feed conversion ratio of control (13.0, WDG 10% (13.2 and 20% (12.1 did not show differences between control and WDG treatments. Thus, the use of WDG up to 20

  14. Effects of calcium oxide treatment of dry and modified wet corn distillers grains plus solubles on growth performance, carcass characteristics, and apparent digestibility of feedlot steers.

    Science.gov (United States)

    Schroeder, A R; Duckworth, M J; Shike, D W; Schoonmaker, J P; Felix, T L

    2014-10-01

    The objectives of this study were to determine the effects of feeding dried corn distillers grains (DDGS) or modified wet corn distillers grains (MDGS) with or without CaO treatment to feedlot steers on 1) growth performance and carcass characteristics and 2) diet digestibility, pattern of intake, and meal distribution. In Exp. 1, steers (n = 139; average initial BW = 336 ± 75 kg) were used in a randomized complete block design. Treatments were arranged in a 2 × 2 factorial design, and pens were randomly allotted to 1 of the 4 dietary treatments (DM basis): 1) 50% DDGS untreated, 2) 48.8% DDGS treated with 1.2% CaO, 3) 50% MDGS untreated, or 4) 48.8% MDGS treated with 1.2% CaO. The remainder of the diet was corn husklage, dry rolled corn, and vitamin and mineral supplement. In Exp. 2, fistulated steers (n = 8; average initial BW = 540 ± 250 kg) were used in a replicated 4 × 4 Latin square design with the same dietary treatments as in Exp. 1. There was no interaction (P ≥ 0.14) between distillers grains plus solubles (DGS) and CaO inclusion for DMI, ADG, final BW, or USDA yield and quality grades. However, steers fed CaO-treated DGS had decreased (P < 0.01) DMI, regardless of DGS type. Because CaO treatment decreased DMI without affecting (P = 0.66) ADG, steers fed CaO-treated DGS had increased (P < 0.01) G:F compared to steers not fed CaO. The variation in DMI found in this experiment could be explained by differences in meal size and distribution. Steers fed CaO-treated DGS ate a similar (P = 0.36) number of meals but ate smaller (P < 0.01) meals. No effects (P ≥ 0.55) of CaO treatment or its interaction with DGS type were found for apparent total tract DM or NDF digestibility. However, steers fed MDGS had increased (P < 0.01) NDF digestibility compared to steers fed DDGS. In conclusion, CaO treatment of DGS improved feed efficiency when DGS-based diets were fed but did not improve digestibility.

  15. Alterations in serotonin receptor-induced contractility of bovine lateral saphenous vein in cattle grazing endophyte-infected tall fescue.

    Science.gov (United States)

    Klotz, J L; Brown, K R; Xue, Y; Matthews, J C; Boling, J A; Burris, W R; Bush, L P; Strickland, J R

    2012-02-01

    As part of a 2-yr study documenting the physiologic impact of grazing endophyte-infected tall fescue on growing cattle, 2 experiments were conducted to characterize and evaluate effects of grazing 2 levels of toxic endophyte-infected tall fescue pastures on vascular contractility and serotonin receptors. Experiment 1 examined vasoconstrictive activities of 5-hydroxytryptamine (5HT), α-methylserotonin (ME5HT; a 5HT(2) receptor agonist), d-lysergic acid (LSA), and ergovaline (ERV) on lateral saphenous veins collected from steers immediately removed from a high-endophyte-infected tall fescue pasture (HE) or a low-endophyte-infected mixed-grass (LE) pasture. Using the same pastures, Exp. 2 evaluated effects of grazing 2 levels of toxic endophyte-infected tall fescue on vasoconstrictive activities of (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), BW 723C86 (BW7), CGS-12066A (CGS), and 5-carboxamidotryptamine hemiethanolate maleate (5CT), agonists for 5HT(2A),( 2B), 5HT(1B), and 5HT(7) receptors, respectively. One-half of the steers in Exp. 2 were slaughtered immediately after removal from pasture, and the other one-half were fed finishing diets for >91 d before slaughter. For Exp. 1, maximal contractile intensities were greater (P 91 d. Experiment 1 demonstrated that grazing of HE pastures for 89 to 105 d induces functional alterations in blood vessels, as evidenced by reduced contractile capacity and altered serotonergic receptor activity. Experiment 2 demonstrated that grazing HE pastures alters vascular responses, which may be mediated through altered serotonin receptor activities, and these alterations may be ameliorated by the removal of ergot alkaloid exposure as demonstrated by the absence of differences in finished steers.

  16. Effects of dry-rolled or high-moisture corn with twenty-five or forty-five percent wet distillers' grains with solubles on energy metabolism, nutrient digestibility, and macromineral balance in finishing beef steers

    Science.gov (United States)

    The effects of feeding dry-rolled corn (DRC) or high-moisture corn (HMC) with 25% and 45% wet distillers grains with solubles (WDGS) on energy metabolism, and nutrient and mineral balance were evaluated in 8 finishing beef steers using a replicated Latin square design. The model included the fixed ...

  17. Growth, carcass and meat quality traits in beef from Angus, Hereford and cross-breed grazing steers, and their association with SNPs in genes related to fat deposition metabolism.

    Science.gov (United States)

    Papaleo Mazzucco, J; Goszczynski, D E; Ripoli, M V; Melucci, L M; Pardo, A M; Colatto, E; Rogberg-Muñoz, A; Mezzadra, C A; Depetris, G J; Giovambattista, G; Villarreal, E L

    2016-04-01

    Grazing steers from Angus and Hereford breeds, their cross-breeds and a three-way cross-breed (Limousin × Angus-Hereford) were measured for growth, carcass and meat quality traits. Breed effects were studied, and the association of SNPs with fat deposition and fatty acid (FA) composition (leptin, melanocortin-4 receptor, stearoyl-CoA desaturase, FA synthase and thyroglobulin) was tested. Limousin cross-breed showed the greatest final body weight, ultrasound rib eye area, dressing percentage, carcass and leg length, and the lowest backfat thickness and intramuscular fat content. Genetic groups had similar pH, shear force, cooking loss, L* and b* and n-6:n-3 ratio. Meat from 1/2-Angus presented greater a* than Limousin cross-breed. Whereas Angus had the highest total SFA content, Hereford had the lowest total SFA and the highest total MUFA. Limousin cross-breed had greater content of several individual PUFAs, total PUFA, n-6 and n-3 FA than Angus and 1/2-Angus. Leptin and FA synthase were associated with some FAs, supporting their influence over fat metabolism for grazing animals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Weight gain and behavior of Raramuri Criollo versus Corriente steers developed on Chihuahuan Desert rangeland

    Science.gov (United States)

    Ranchers that raise Criollo cattle must overcome the challenge of lack of markets for weaned calves. Raramuri Criollo (RC) steers are commonly raised for beef and finished on rangelands, while Corriente (CR) are often raised for rodeo sports. No data exist on weight gains and grazing behavior of ran...

  19. Weight gain and behavior of Raramuri Criollo versus crossbred steers developed on Chihuahuan Desert rangeland

    Science.gov (United States)

    Ranchers that raise Raramuri Criollo (RC) cattle must overcome the challenge of lack of markets for weaned calves. Growing and finishing RC or RC-crossbred steers on rangeland pastures is increasingly common; however, no data exist on their weight gains or grazing behavior. We tracked the weight a...

  20. Riparian Meadow Response to Modern Conservation Grazing Management

    Science.gov (United States)

    Oles, Kristin M.; Weixelman, Dave A.; Lile, David F.; Tate, Kenneth W.; Snell, Laura K.; Roche, Leslie M.

    2017-09-01

    Riparian meadows occupy a small proportion of the public lands in the western United States but they provide numerous ecosystem services, including the production of high-quality forage for livestock grazing. Modern conservation management strategies (e.g., reductions in livestock stocking rates and adoption of new riparian grazing standards) have been implemented to better balance riparian conservation and livestock production objectives on publicly managed lands. We examined potential relationships between long-term changes in plant community, livestock grazing pressure and environmental conditions at two spatial scales in meadows grazed under conservation management strategies. Changes in plant community were not associated with either livestock stocking rate or precipitation at the grazing allotment (i.e., administrative) scale. Alternatively, both grazing pressure and precipitation had significant, albeit modest, associations with changes in plant community at the meadow (i.e., ecological site) scale. These results suggest that reductions in stocking rate have improved the balance between riparian conservation and livestock production goals. However, associations between elevation, site wetness, precipitation, and changes in plant community suggest that changing climate conditions (e.g., reduced snowpack and changes in timing of snowmelt) could trigger shifts in plant communities, potentially impacting both conservation and agricultural services (e.g., livestock and forage production). Therefore, adaptive, site-specific management strategies are required to meet grazing pressure limits and safeguard ecosystem services within individual meadows, especially under more variable climate conditions.

  1. Effects of feeding corn modified wet distillers grain plus solubles co-ensiled with direct-cut forage on feedlot performance, carcass characteristics, and diet digestibility of finishing steers.

    Science.gov (United States)

    Arias, R P; Unruh-Snyder, L J; Scholljegerdes, E J; Baird, A N; Johnson, K D; Buckmaster, D; Lemenager, R P; Lake, S L

    2012-10-01

    Two experiments were conducted to evaluate the effects of feeding corn modified wet distillers grain plus solubles (MWDGS) co-ensiled with direct-cut forage (DC) to beef steers, on feedlot performance and total tract digestibility. In Exp. 1, sixty-four crossbred Angus steers (n = 64; 329 ± 43 kg) were blocked by BW and randomly assigned to 1 of 4 dietary treatments: 1) corn-silage and soybean meal (CON), 2) DC co-ensiled with MWDGS (CO-EN), 3) haylage mixed with MWDGS at feeding (H+WDG), and 4) haylage mixed with dry distillers grains plus solubles at feeding (H+DDG). Steers were harvested when they reached an endpoint of 1.1 cm of 12th-rib back fat. In Exp. 2, four ruminally cannulated beef steers (initial BW = 556 ± 31 kg) were used in a 4 × 4 Latin square to evaluate digestibility of diets used in Exp. 1. Experimental periods were 14 d in length with 10 d for diet adaptation and 4 d for sample collection. Three linear orthogonal contrasts were used to compare effects of 1) CON vs. diets containing distillers grains (DGD), 2) CO-EN vs. diets where distillers grains were mixed at feeding (MIX), and 3) H+WDG vs. H+DDG. In Exp. 1, DMI was less (P 0.10) in DM, OM, or N intakes were observed. Apparent total tract DM (P = 0.01) and N (P = 0.02) digestibility were greatest in steers fed CON compared with all others. Steers fed DGD had less (P = 0.02) rumen NH(3) concentrations compared with CON. The CON diet resulted in greater molar concentrations of VFA (P = 0.03) and decreased acetate to propionate ratio (P = 0.03) compared with all DGD. These data suggest that feeding MWDGS co-ensiled with direct-cut forage results in reduced diet digestibility but equal or greater feedlot performance and similar carcass and characteristics when compared with a corn diet supplemented with soybean meal and diets where MWDGS and DDGS were added at the mixer.

  2. Characteristics of Wet Distillers Grains on Ruminal Fermentation and Its Effects on Performance and Carcass Characteristics of Finishing Hanwoo Steers

    Directory of Open Access Journals (Sweden)

    Gyu Chul Ahn

    2016-04-01

    Full Text Available Two experiments were conducted to determine the nutrient composition, in vitro ruminal ammonia concentrations and pH of wet distillers grains (WDG, produced from tapioca 70% and rice 30% and to evaluate dietary effects of fermented total mixed ration (TMR using WDG on the performance, blood metabolites and carcass characteristics of Hanwoo steers from mid fattening to slaughter. In Exp. I, average dry matter (DM, crude protein, ether extract, crude fiber, ash, neutral detergent fiber, acid detergent fiber, and nitrogen free extract of seven WDG samples from an ethanol plant with different sampling dates were 19.9%, 24.8%, 3.8%, 21.8%, 8.87%, 60.3%, 34.5%, and 40.7% (DM basis, respectively. For in vitro ammonia concentrations and pH, each sample was assigned to 7 incubation times (0, 4, 8, 12, 24, 48, and 72 h. Linear increase was observed between 12 and 48 h for ammonia concentrations, but final ammonia concentrations (72 h were not significantly different among WDG samples and fermentation patterns of WDG samples showed similar tendency. In vitro pH varied among treatments from 0 to 24 h, but were not different statistically after 48 h. In Exp. II, 45 Hanwoo steers of 23 months (641±123 kg from mid fattening period to slaughter (248 days were randomly divided into three groups of 15 pens each (five repetitions/each treatment and assigned to one of three dietary treatments; i Control (TMR, ii WDG 15 (TMR containing 15% of WDG, as fed basis and iii WDG 28 (TMR containing 28% of WDG, as fed basis. The body weight (BW, ADG, and feed conversion ratio (FCR of control and WDG 15 and 28 during 248 days were 760.8, 740.1, and 765.5 kg, and 0.50, 0.50, and 0.52 kg/d, and 18.6, 17.6, and 17.1, respectively. The dry matter intake (DMI (kg/d of control (9.11 was higher (p<0.05 than WDG treatments (WDG 15%, 8.57; 28%, 8.70. Nevertheless, DMI did not affect BW, ADG, and FCR of Hanwoo finishing steers. Blood metabolites were in normal ranges and were not

  3. Livestock grazing intensity affects abundance of Common shrews (Sorex araneus) in two meadows in Denmark

    Science.gov (United States)

    Schmidt, Niels M; Olsen, Henrik; Leirs, Herwig

    2009-01-01

    Background Current nature conservation in semi-natural grasslands often includes grazing and hay cutting, as well as the abandonment of draining. Semi-natural grassland and in particular meadows constitute important habitat type for a large number of animal species in today's fragmented and intensively cultivated landscape of Europe. Here we focus on the population characteristics of Common shrews Sorex araneus in relation to livestock grazing intensity in two wet meadows in western Denmark. Results High grazing intensity had a significant negative effect on Common shrew number compared to low grazing intensity and no grazing. Common shrew abundance was generally, but not significantly, higher on the low grazing intensity plots than on the ungrazed controls. No differences in body mass, sex ratio, or reproductive output between Common shrew individuals from the various grazing treatments were found. Conclusion No negative effects of low intensity grazing on Common shrew abundance were found compared to the ungrazed control. Low intensity grazing thus seems a suitable management regime for Common shrews, when grazing is needed as part of the meadow management scheme. High intensity grazing on the other hand is not a suitable management tool. PMID:19152713

  4. Livestock grazing intensity affects abundance of Common shrews (Sorex araneus in two meadows in Denmark

    Directory of Open Access Journals (Sweden)

    Olsen Henrik

    2009-01-01

    Full Text Available Abstract Background Current nature conservation in semi-natural grasslands often includes grazing and hay cutting, as well as the abandonment of draining. Semi-natural grassland and in particular meadows constitute important habitat type for a large number of animal species in today's fragmented and intensively cultivated landscape of Europe. Here we focus on the population characteristics of Common shrews Sorex araneus in relation to livestock grazing intensity in two wet meadows in western Denmark. Results High grazing intensity had a significant negative effect on Common shrew number compared to low grazing intensity and no grazing. Common shrew abundance was generally, but not significantly, higher on the low grazing intensity plots than on the ungrazed controls. No differences in body mass, sex ratio, or reproductive output between Common shrew individuals from the various grazing treatments were found. Conclusion No negative effects of low intensity grazing on Common shrew abundance were found compared to the ungrazed control. Low intensity grazing thus seems a suitable management regime for Common shrews, when grazing is needed as part of the meadow management scheme. High intensity grazing on the other hand is not a suitable management tool.

  5. Vehicle steering by side stick: optimising steering characteristics

    NARCIS (Netherlands)

    Zuurbier, J.; Hogema, J.H.; Brekelmans, J.A.W.J.

    2000-01-01

    This paper describes a study that was conducted to investigate the possibilities for optimizing task performance when driving a side stick-steered vehicle. Using steer-by-wire technology, a conventional steering system was mimicked, thus yielding the possibility to modify the steering

  6. Biological soil crusts exhibit a dynamic response to seasonal rain and release from grazing with implications for soil stability

    Science.gov (United States)

    Jimenez, Aguilar A.; Huber-Sannwald, E.; Belnap, J.; Smart, D.R.; Arredondo, Moreno J.T.

    2009-01-01

    In Northern Mexico, long-term grazing has substantially degraded semiarid landscapes. In semiarid systems, ecological and hydrological processes are strongly coupled by patchy plant distribution and biological soil crust (BSC) cover in plant-free interspaces. In this study, we asked: 1) how responsive are BSC cover/composition to a drying/wetting cycle and two-year grazing removal, and 2) what are the implications for soil erosion? We characterized BSC morphotypes and their influence on soil stability under grazed/non-grazed conditions during a dry and wet season. Light- and dark-colored cyanobacteria were dominant at the plant tussock and community level. Cover changes in these two groups differed after a rainy season and in response to grazing removal. Lichens with continuous thalli were more vulnerable to grazing than those with semi-continuous/discontinuous thalli after the dry season. Microsites around tussocks facilitated BSC colonization compared to interspaces. Lichen and cyanobacteria morphotypes differentially enhanced resistance to soil erosion; consequently, surface soil stability depends on the spatial distribution of BSC morphotypes, suggesting soil stability may be as dynamic as changes in the type of BSC cover. Longer-term spatially detailed studies are necessary to elicit spatiotemporal dynamics of BSC communities and their functional role in biotically and abiotically variable environments. ?? 2009 Elsevier Ltd.

  7. Cyanobacterial crusts linked to soil productivity under different grazing management practices in Northern Australia

    Science.gov (United States)

    Alchin, Bruce; Williams, Wendy

    2015-04-01

    In arid and semi-arid Australia, the central role of healthy soil ecosystems in broad-acre grazing lands may be attributed to the widespread presence of cyanobacterial crusts. In terms of soil nutrient cycling and stability their role is particularly crucial in a climate dominated by annual dry seasons and variable wet seasons. In this study, we aimed to measure the contribution of cyanobacteria to soil nutrient cycling under contrasting levels of disturbance associated with grazing management. Field sampling was carried out on six paired sites (twelve properties) located across an east-west 3,000 km transect that covered different rangeland types on grazing properties in northern Australia (Queensland, Northern Territory and Western Australia). At each location paired sites were established and two different management systems were assessed, cell-paddock rotations (25-400 ha) and continuous grazing (200-2,000 ha). Cyanobacterial soil crusts were recorded from all of the twelve sites and cyanobacteria with the capacity to fix nitrogen were found at ten of the twelve sites. The overall diversity of cyanobacteria varied from three to ten species under any type of grazing system. As field work was conducted in the dry season, it is likely that the diversity may be greater in the wet season than the initial data may indicate. The average cyanobacterial soil crust cover across soil surfaces, between grass tussocks, during the dry season was estimated to be 50.9% and, 42.6% in the early wet season. This reflected longer established crust cover (dry season) versus newly established crusts. There was a high level of variability in the biomass of cyanobacteria however; the grazing system did not have any marked effect on the biomass for any one rangeland type. The grazing system differences did not appear to significantly influence the diversity at any location except on a floodplain in the Pilbara (WA). Biological nitrogen fixation by cyanobacteria was recorded at all

  8. Herbage intake, methane emissions and animal performance of steers grazing dwarf elephant grass v. dwarf elephant grass and peanut pastures.

    Science.gov (United States)

    Andrade, E A; Almeida, E X; Raupp, G T; Miguel, M F; de Liz, D M; Carvalho, P C F; Bayer, C; Ribeiro-Filho, H M N

    2016-10-01

    Management strategies for increasing ruminant legume consumption and mitigating methane emissions from tropical livestock production systems require further study. The aim of this work was to evaluate the herbage intake, animal performance and enteric methane emissions of cattle grazing dwarf elephant grass (DEG) (Pennisetum purpureum cv. BRS Kurumi) alone or DEG with peanut (Arachis pintoi cv. Amarillo). The experimental treatments were the following: DEG pastures receiving nitrogen fertilization (150 kg N/ha as ammonium nitrate) and DEG intercropped with peanut plus an adjacent area of peanut that was accessible to grazing animals for 5 h/day (from 0700 to 1200 h). The animals grazing legume pastures showed greater average daily gain and herbage intake, and shorter morning and total grazing times. Daily methane emissions were greater from the animals grazing legume pastures, whereas methane emissions per unit of herbage intake did not differ between treatments. Allowing animals access to an exclusive area of legumes in a tropical grass-pasture-based system can improve animal performance without increasing methane production per kg of dry matter intake.

  9. Technical Note: Daily variation in intake of a salt-limited supplement by grazing steers

    Science.gov (United States)

    The objective of this research was to develop and test an automated supplement intake measurement system (SmartFeed, SF) in grazing trials. The SF was developed by C-lock Inc., (Rapid City, SD), and was designed using a stainless steel feed bin with load cells and an radio frequency identification ...

  10. Livestock grazing intensity affects abundance of Common shrews (Sorex araneus) in two meadows in Denmark

    OpenAIRE

    Schmidt, Niels M; Olsen, Henrik; Leirs, Herwig

    2009-01-01

    Abstract Background Current nature conservation in semi-natural grasslands often includes grazing and hay cutting, as well as the abandonment of draining. Semi-natural grassland and in particular meadows constitute important habitat type for a large number of animal species in today's fragmented and intensively cultivated landscape of Europe. Here we focus on the population characteristics of Common shrews Sorex araneus in relation to livestock grazing intensity in two wet meadows in western ...

  11. Studies of transuranic element ingestion by fistulated steers grazing Area 13 of the Nevada Test Site

    International Nuclear Information System (INIS)

    Blincoe, C.; Bohman, V.R.; Smith, D.D.

    1985-01-01

    Area 13 is one of several areas of the Nevada Test Site (NTS) contaminated with transuranics. Cattle were grazed on the area to study the botanical and chemical composition of the forage, the digestibility of range plants as selected by range cattle, and the intake of plutonium and americium by grazing cattle. The digestibility of dry matter ranged from 34 to 44%. Cattle generally consumed over 2 kilograms per 100 kilograms body weight of dry matter daily, which resulted in a daily intake of 3600 to 11,100 pCi of plutonium-238, 85,000 to 400,000 pCi of plutonium-239, and 11,000 to 56,000 pCi of americium-241. The soil ingested by range cattle constituted the principal and possibly only source of ingested plutonium and americium. 21 references, 1 figure, 9 tables

  12. One-way EPR steering and genuine multipartite EPR steering

    Science.gov (United States)

    He, Qiongyi; Reid, Margaret D.

    2012-11-01

    We propose criteria and experimental strategies to realise the Einstein-Podolsky-Rosen (EPR) steering nonlocality. One-way steering can be obtained where there is asymmetry of thermal noise on each system. We also present EPR steering inequalities that act as signatures and suggest how to optimise EPR correlations in specific schemes so that the genuine multipartite EPR steering nonlocality (EPR paradox) can also possibly be realised. The results presented here also apply to the spatially separated macroscopic atomic ensembles.

  13. Steering Maps and Their Application to Dimension-Bounded Steering

    Science.gov (United States)

    Moroder, Tobias; Gittsovich, Oleg; Huber, Marcus; Uola, Roope; Gühne, Otfried

    2016-03-01

    The existence of quantum correlations that allow one party to steer the quantum state of another party is a counterintuitive quantum effect that was described at the beginning of the past century. Steering occurs if entanglement can be proven even though the description of the measurements on one party is not known, while the other side is characterized. We introduce the concept of steering maps, which allow us to unlock sophisticated techniques that were developed in regular entanglement detection and to use them for certifying steerability. As an application, we show that this allows us to go beyond even the canonical steering scenario; it enables a generalized dimension-bounded steering where one only assumes the Hilbert space dimension on the characterized side, with no description of the measurements. Surprisingly, this does not weaken the detection strength of very symmetric scenarios that have recently been carried out in experiments.

  14. Grazing behavior and intake of goats rotationally grazing Tanzania-grass pasture with different post-grazing residues

    Directory of Open Access Journals (Sweden)

    Marcia H.M.R. Fernandes

    2016-05-01

    Full Text Available This study aimed to evaluate intake and ingestive behavior of goats rotationally grazing Tanzania (Panicum maximum cv. Tanzânia 1 pastures with 2 levels of post-grazing residue. The experimental area consisted of 1.2 ha of Tanzania pasture divided into 12 paddocks (24 areas, managed under 2 post-grazing residues: low green (leaf + stem herbage mass (GHM post-grazing (LR, approximately 1,500 kg/ha GHM; and high GHM post-grazing (HR, approximately 3,000 kg/ha GHM. Each paddock was grazed for 3 consecutive days (D1, D2, D3 followed by 33 days rest and evaluated from October 2005 to April 2006. Animal behavior (grazing time, bite rate and bite size/weight was evaluated on each grazing day. While goats spent more time grazing on LR than HR (P=0.02, bite rate did not differ between treatments or among days (P=0.31 and averaged 26.5 bites/min. In contrast, bite weight was greater in HR (0.15 g/bite than in LR (0.12 g/bite, and decreased from D1 to D3 (P<0.001. Absolute dry matter intake of goats was greater in the HR (2.19 kg/d than the LR (1.89 kg/d treatment; however, differences were not significant (P>0.05 when intake was determined on a body weight or metabolic weight basis. Our findings are consistent with the general assumption that bite weight is a trade-off between quantity and quality of the herbage mass and is the main determinant of animal performance. More studies are needed to determine animal performance on the various treatments and to determine management strategies to provide a desirable balance between animal weight gain and pasture stability.Keywords: Animal behavior, foraging, grazing systems, Megathyrsus maximus, plant - animal relations.DOI: 10.17138/TGFT(491-100

  15. Comportamento ingestivo de novilhos de corte em pastagem de aveia preta e azevém com níveis distintos de folhas verdes Ingestive behaviour of beef steers grazing oat and Italian ryegrass pasture with different levels of green leaves

    Directory of Open Access Journals (Sweden)

    Naíme de Barcellos Trevisan

    2004-10-01

    Full Text Available O objetivo deste trabalho foi avaliar como dois níveis distintos de biomassa de folhas verdes, representados por 350 e 600kg ha-1 de matéria seca de folhas verdes (MSFV afetam o comportamento de novilhos de corte e sua taxa de bocados. Para as avaliações de comportamento ingestivo, foi utilizado o método direto de observação visual de animais focais em dois períodos de 24 horas, com início e término às 13:00 horas, durante o ciclo de duração da pastagem, nos dias 16-17/08 e 24-25/09/2002. Para cada turno de seis horas, foram utilizados três observadores treinados, um para cada dois potreiros contíguos (três animais focais por potreiro. A intervalos de 10 minutos eram registrados as atividades de pastejo, ruminação, ócio e realizadas medidas relativas à taxa de bocados, correspondente ao número de bocados de apreensão por minuto. A menor porcentagem de matéria seca existente na pastagem durante a primeira avaliação do comportamento ingestivo foi responsável pelo aumento no tempo de pastejo, na comparação entre períodos. A atividade complementar ao pastejo, na primeira avaliação, foi a ruminação, sem diferenças para ócio. As mais baixas biomassas induziram os animais a aumentar o número de bocados como forma de otimizar o consumo de forragem.The objective of this trial was to evaluate how two levels of green leaves biomass, represented by 350 and 600kg ha-1 of green leaves dry matter (GLDM affected beef steers behaviour and its bite rate. Evaluations of ingestive behaviour were performed with focal animals observed visually on two periods of 24 hours, with beginning and end at 01 pm, during pasture growth season, at 08/16-17 and 09/24-25/2002. Three trained observers were used for each turn of six hours, one for each two contiguous paddocks (where three focal animals grazed. At 10 minutes intervals, grazing time, rumination activities and rest were registered and estimated the bite rate, as the number of

  16. Livestock grazing intensity affects abundance of Common shrews (Sorex araneus) in two meadows in Denmark

    DEFF Research Database (Denmark)

    Schmidt, Niels Martin; Olsen, Henrik; Leirs, Herwig

    2009-01-01

    habitat type for a large number of animal species in today's fragmented and intensively cultivated landscape of Europe. Here we focus on the population characteristics of Common shrews Sorex araneus in relation to livestock grazing intensity in two wet meadows in western Denmark. Results: High grazing...... as well as in most other European countries, the amount of land covered by semi-natural grassland has decreased dramatically during the 20th century concurrent with the general intensification of the agricultural production. To reverse this trend, actions are being taken in many places to either maintain...

  17. Grazing studies on a plutonium-contaminated range of the Nevada Test Site

    International Nuclear Information System (INIS)

    Smith, D.D.; Barth, J.; Patzer, R.G.

    1976-01-01

    A grazing study on a plutonium-contaminated range on the Nevada Test Site was initiated in May 1973 and is continuing. The primary objective of this study is to determine the uptake and tissue distribution of the plutonium by ruminants. Other objectives are to evaluate maternal-foetal transfer, to determine uptake and distribution differences in young versus mature animals, and to compare these data with those collected from other contaminated areas. Steers with surgically prepared rumen fistulas served as biological samplers to determine grazing habits (quantity and type of forage ingested) as a function of seasonal plant availability and preference, to estimate intake of actinides over specified periods of time, and to determine the actinide ratios within the ingesta. Since the study began tissue samples have been collected from seven cows, four calves, and three foetusses. All animals sacrificed were necropsied and selected tissue and organ samples collected for histo-pathological examination and actinide analyses. No significant lesions have been found and actinide accumulations in the tissues have been relatively minimal. Using activity levels found in the rumen contents of fistulated steers, it was estimated that a study cow ingested 100μCi prior to sacrifice. Of this, 16.4μCi was in rumen fluids from which a combined retention factor of 0.0034% was calculated for the bone, muscle and liver. Comparisons of 239 Pu/ 238 Pu ratios in ingesta and tissues indicate that the 238 Pu is more readily absorbed and retained. Analysis of ingesta from the fistulated steers indicates that grasses are preferred in the late spring and early summer months, with shrubs making up the bulk of the diet the rest of the year. Plutonium acitivity in rumen contents was higher when Eurotia lanata was the preferred shrub species. Studies on labelled particles indicate that ingested particles from 75 to 500μm in size have a half-time of 3.5 to 5 days in the intestinal tract, while

  18. Aridity and grazing as convergent selective forces: an experiment with an Arid Chaco bunchgrass.

    Science.gov (United States)

    Quiroga, R Emiliano; Golluscio, Rodolfo A; Blanco, Lisandro J; Fernández, Roberto J

    2010-10-01

    It has been proposed that aridity and grazing are convergent selective forces: each one selects for traits conferring resistance to both. However, this conceptual model has not yet been experimentally validated. The aim of this work was to experimentally evaluate the effect of aridity and grazing, as selective forces, on drought and grazing resistance of populations of Trichloris crinita, a native perennial forage grass of the Argentinean Arid Chaco region. We collected seeds in sites with four different combinations of aridity and grazing history (semiarid/ subhumid x heavily grazed/lightly grazed), established them in pots in a common garden, and subjected the resulting plants to different combinations of drought and defoliation. Our results agreed with the convergence model. Aridity has selected T. crinita genotypes that respond better to drought and defoliation in terms of sexual reproduction and leaf growth, and that can evade grazing due to a lower shoot: root ratio and a higher resource allocation to reserves (starch) in stem bases. Similarly, grazing has selected genotypes that respond better to drought and defoliation in terms of sexual reproduction and that can evade grazing due to a lower digestibility of leaf blades. These results allow us to extend concepts of previous models in plant adaptation to herbivory to models on plant adaptation to drought. The only variable in which we obtained a result opposite to predictions was plant height, as plants from semiarid sites were taller (and with more erect tillers) than plants from subhumid sites; we hypothesize that this result might have been a consequence of the selection exerted by the high solar radiation and soil temperatures of semiarid sites. In addition, our work allows for the prediction of the effects of dry or wet growing seasons on the performance of T. crinita plants. Our results suggest that we can rely on dry environments for selecting grazing-resistant genotypes and on high grazing pressure

  19. Equine Grazing in Managed Subalpine Wetlands: Effects on Arthropods and Plant Structure as a Function of Habitat

    Science.gov (United States)

    Holmquist, Jeffrey G.; Schmidt-Gengenbach, Jutta; Haultain, Sylvia A.

    2013-12-01

    Grazing management necessarily emphasizes the most spatially extensive vegetation assemblages, but landscapes are mosaics, often with more mesic vegetation types embedded within a matrix of drier vegetation. Our primary objective was to contrast effects of equine grazing on both subalpine vegetation structure and associated arthropods in a drier reed grass ( Calamagrostis muiriana) dominated habitat versus a wetter, more productive sedge habitat ( Carex utriculata). A second objective was to compare reed grass and sedge as habitats for fauna, irrespective of grazing. All work was done in Sequoia National Park (CA, USA), where detailed, long-term records of stock management were available. We sampled paired grazed and control wet meadows that contained both habitats. There were moderate negative effects of grazing on vegetation, and effects were greater in sedge than in reed grass. Conversely, negative grazing effects on arthropods, albeit limited, were greater in the drier reed grass, possibly due to microhabitat differences. The differing effects on plants and animals as a function of habitat emphasize the importance of considering both flora and fauna, as well as multiple habitat types, when making management decisions. Sedge supported twice the overall arthropod abundance of reed grass as well as greater diversity; hemipteran and dipteran taxa were particularly abundant in sedge. Given the greater grazing effects on sedge vegetation, greater habitat provision for terrestrial arthropods, and value as aquatic arthropod habitat, the wetter sedge assemblage is worthy of additional consideration by managers when planning for grazing and other aspects of land usage.

  20. Online optimized hysteresis-based steering feel model for steer-by-wire systems

    Directory of Open Access Journals (Sweden)

    Ahmet Kirli

    2016-06-01

    Full Text Available In rubber-wheeled road vehicles, the mechanical connection between steering wheel and front wheels provides steering-related feedback to the driver. The torque fed back to the driver through the steering linkages and steering wheel, which is called steering feel, helps the driver in controlling the vehicle. The torque feedback is reproduced via artificial methods in steer-by-wire systems due to the lack of mechanical connection. In this work, in order to minimize the physical workload and the lateral acceleration under the consideration of handling performance, optimization of a hysteresis-based steering feel has been studied. A 2-degree-of-freedom bicycle model based on the magic formula tire model has been used for simulations and hardware-in-the-loop experiments. A mathematical model is proposed in order to create an adaptive model-based optimization of the hysteresis parameters simultaneously while driving. A hardware-in-the-loop experimental setup has been used for the driving tests. The weave and the double-lane change tests have been performed with different drivers in order to demonstrate and quantify the optimization methods that are presented in this work.

  1. A new model to compute the desired steering torque for steer-by-wire vehicles and driving simulators

    Science.gov (United States)

    Fankem, Steve; Müller, Steffen

    2014-05-01

    This paper deals with the control of the hand wheel actuator in steer-by-wire (SbW) vehicles and driving simulators (DSs). A novel model for the computation of the desired steering torque is presented. The introduced steering torque computation does not only aim to generate a realistic steering feel, which means that the driver should not miss the basic steering functionality of a modern conventional steering system such as an electric power steering (EPS) or hydraulic power steering (HPS), and this in every driving situation. In addition, the modular structure of the steering torque computation combined with suitably selected tuning parameters has the objective to offer a high degree of customisability of the steering feel and thus to provide each driver with his preferred steering feel in a very intuitive manner. The task and the tuning of each module are firstly described. Then, the steering torque computation is parameterised such that the steering feel of a series EPS system is reproduced. For this purpose, experiments are conducted in a hardware-in-the-loop environment where a test EPS is mounted on a steering test bench coupled with a vehicle simulator and parameter identification techniques are applied. Subsequently, how appropriate the steering torque computation mimics the test EPS system is objectively evaluated with respect to criteria concerning the steering torque level and gradient, the feedback behaviour and the steering return ability. Finally, the intuitive tuning of the modular steering torque computation is demonstrated for deriving a sportier steering feel configuration.

  2. On Electrohydraulic Pressure Control for Power Steering Applications : Active Steering for Road Vehicles

    OpenAIRE

    Dell'Amico, Alessandro

    2016-01-01

    This thesis deals with the Electrohydraulic Power Steering system for road vehicles, using electronic pressure control valves. With an ever increasing demand for safer vehicles and fewer traffic accidents, steering-related active safety functions are becoming more common in modern vehicles. Future road vehicles will also evolve towards autonomous vehicles, with several safety, environmental and financial benefits. A key component in realising such solutions is active steering. The power steer...

  3. Consumo e digestibilidade de novilhos Nelore sob pastagem suplementados com misturas múltiplas Intake and digestibility of Nelore steers grazing pasture and supplemented with multiple mixture

    Directory of Open Access Journals (Sweden)

    L.O.F. Oliveira

    2004-02-01

    Full Text Available Estudou-se o efeito da suplementação com misturas múltiplas sobre o consumo, digestibilidade e desempenho de novilhos Nelore, em pastagens de Brachiaria brizantha Cv. Marandu, submetidos a quatro tratamentos. No tratamento um (T1, cada animal recebeu 800g/dia de suplemento contendo uréia como fonte de nitrogênio não protéico (NNP; no tratamento dois (T2, recebeu 800g/dia de mistura na qual a uréia foi substituída por amiréia como fonte de NNP; no tratamento três (T3, recebeu 1500g/dia de uma mistura com amiréia; e no tratamento quatro (T4= controle, recebeu sal mineral. Seis animais por tratamento foram utilizados para se medir o consumo pela técnica de indicador externo (óxido crômico, e 10 animais foram usados na avaliação de ganho de peso. Foram utilizados dois animais canulados no esôfago para coleta de amostra de extrusa. Os animais suplementados obtiveram ganhos de peso superiores (PThe effect of three multiple mixtures supplementation on intake, digestibility and performance of Nelore steers grazing pasture of Brachiaria decumbens CV Marandu was studied. The multiple mixtures (treatments - T were defined as: T1 - 800g of supplement with urea as crude protein source, T2 - 800g of mixture in which urea was replaced by starea, T3 - 1500g of starea, and T4 - mineral salt fed ad libitum as a control group. Six animals per treatment were given chromic oxide as a marker to measure intake and 10 animals per treatment were used to evaluate their performance. Two esophageal fistulated steers were used to collect samples of extruse. The animals fed on supplement diets showed higher weight gains (335, 419, 467g/animal than those from the control group (271g/animal. Dry matter digestibility were 56.7, 49.8, 48.9 and 45.5%, respectively, for T1, T2, T3 and T4. A positive correlation between dry matter digestibility and in vitro dry matter digestibility (P<0.05 was observed. Supplementation with multiple mixtures increased dry matter

  4. 49 CFR 570.7 - Steering systems.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Steering systems. 570.7 Section 570.7... Pounds or Less § 570.7 Steering systems. (a) System play. Lash or free play in the steering system shall... in the steering system. Table 1—Steering System Free Play Values Steering wheel diameter (inches...

  5. Experimental verification of multidimensional quantum steering

    Science.gov (United States)

    Li, Che-Ming; Lo, Hsin-Pin; Chen, Liang-Yu; Yabushita, Atsushi

    2018-03-01

    Quantum steering enables one party to communicate with another remote party even if the sender is untrusted. Such characteristics of quantum systems not only provide direct applications to quantum information science, but are also conceptually important for distinguishing between quantum and classical resources. While concrete illustrations of steering have been shown in several experiments, quantum steering has not been certified for higher dimensional systems. Here, we introduce a simple method to experimentally certify two different kinds of quantum steering: Einstein-Podolsky-Rosen (EPR) steering and single-system (SS) steering (i.e., temporal steering), for dimensionality (d) up to d = 16. The former reveals the steerability among bipartite systems, whereas the latter manifests itself in single quantum objects. We use multidimensional steering witnesses to verify EPR steering of polarization-entangled pairs and SS steering of single photons. The ratios between the measured witnesses and the maximum values achieved by classical mimicries are observed to increase with d for both EPR and SS steering. The designed scenario offers a new method to study further the genuine multipartite steering of large dimensionality and potential uses in quantum information processing.

  6. Driver steering model for closed-loop steering function analysis

    Science.gov (United States)

    Bolia, Pratiksh; Weiskircher, Thomas; Müller, Steffen

    2014-05-01

    In this paper, a two level preview driver steering control model for the use in numerical vehicle dynamics simulation is introduced. The proposed model is composed of cascaded control loops: The outer loop is the path following layer based on potential field framework. The inner loop tries to capture the driver's physical behaviour. The proposed driver model allows easy implementation of different driving situations to simulate a wide range of different driver types, moods and vehicle types. The expediency of the proposed driver model is shown with the help of developed driver steering assist (DSA) function integrated with a conventional series production (Electric Power steering System with rack assist servo unit) system. With the help of the DSA assist function, the driver is prevented from over saturating the front tyre forces and loss of stability and controllability during cornering. The simulation results show different driver reactions caused by the change in the parameters or properties of the proposed driver model if the DSA assist function is activated. Thus, the proposed driver model is useful for the advanced driver steering and vehicle stability assist function evaluation in the early stage of vehicle dynamics handling and stability evaluation.

  7. Study on control schemes of flexible steering system of a multi-axle all-wheel-steering robot

    Directory of Open Access Journals (Sweden)

    Pingxia Zhang

    2016-05-01

    Full Text Available It is well known that a multi-axle wheeled robot possesses larger load capability and also higher drive performance. However, its steering flexibility is degraded due to the large number of wheels. In order to solve this problem, in this article, we proposed three control schemes based on the center of rotation or the steering angles of both the first- and last-axle wheels. To release these control schemes, steering mode selection and also the left wheel’s steering angle in a specific axle are added approaching a practical application. Thereafter, the remaining wheels’ steering angles can be calculated with the Ackerman steering theorem. In order to verify the control effects, a five-axle all-wheel-steering wheeled robot has been developed with the Bluetooth wireless monitor system. Based on the newly designed robot, validation experiments are carried out, such as lateral movement, situ rotation, and multi-mode steering within a narrow space. The results indicate that the proposed design in this article can ensure a more flexible and faster movement within a narrow space. It shows large potential in obstacle avoidance compared with the conventional partial-wheel steering mode.

  8. Steering smog prediction

    NARCIS (Netherlands)

    R. van Liere (Robert); J.J. van Wijk (Jack)

    1997-01-01

    textabstractThe use of computational steering for smog prediction is described. This application is representative for many underlying issues found in steering high performance applications: high computing times, large data sets, and many different input parameters. After a short description of the

  9. A Frictionless Steering Mechanism for the Front Steering ECCD ITER Upper Port Launcher

    International Nuclear Information System (INIS)

    Chavan, R; Henderson, M A; Sanchez, F

    2005-01-01

    A FS launcher is being designed for the ITER upper port, which offers enhanced physics performance over the RS launcher. A two mirror system is used to decouple the focusing and steering aspects of the launcher and provide a relatively small beam waist ( 1.6 m from the steering mirror). The resulting NTM stabilization efficiency (maximum CD density divided by the local bootstrap current >1.6) is above marginal for the q = 2 and 3/2 rational flux surfaces of the relevant ITER equilibria (scenarios 2, 3a and 5) and a factor of ∼3 relative to an equivalent RS launcher. The performance of the FS launcher strongly depends on the reliability of the steering mechanism, which is used to rotate the plasma facing steering mirror. CRPP has designed a frictionless steering mechanism assembled in a compact cartridge capable of up to ±10 deg. rotation (corresponding to a poloidal steering range of up to ±20 deg. for the microwave beam around a fixed axis of rotation) that offers a high operation reliability despite the close proximity to the thermal and neutron flux coming from the ITER plasma

  10. Effect of inclusion of different levels of silage on rumen microbial population and microbial protein synthesis in dairy steers fed on rice straw

    Directory of Open Access Journals (Sweden)

    Thien Truong Giang Nguyen

    2017-02-01

    Full Text Available Objective Leucaena leucocephala (Leucaena is a perennial tropical legume that can be directly grazed or harvested and offered to ruminants as hay, silage, or fresh. However, Leucaena contain phenolic compounds, which are considered anti-nutritional factors as these may reduce intake, digestibility and thus animal performance. Therefore, the objective of this experiment was to determine effects of Leucaena silage (LS feeding levels on rumen microbial populations, N-balance and microbial protein synthesis in dairy steers. Methods Four, rumen fistulated dairy steers with initial weight of 167±12 kg were randomly assigned to receive dietary treatments according to a 4×4 Latin square design. Treatments were as followings: T1 = untreated rice straw (RS; Control, T2 = 70% RS+30% LS, T3 = 40% RS+60% LS, and T4 = 100% LS. Dairy steers were fed rice straw and LS ad libitum and supplemented with concentrate at 0.2% of body weight/d. Results Results revealed that the rumen microbial population, especially cellulolytic, proteolytic bacteria and fungal zoospores were enhanced in steers that received 60% of LS (p0.05. Protozoal population was linearly decreased with increasing level of LS (p<0.05. Moreover, N-balance and microbial protein synthesis were enhanced by LS feeding (p<0.05 and were the highest in 60% LS group. Conclusion Based on this study, it could be concluded that replacement of RS with 60% LS significantly improved microbial population and microbial protein synthesis in diary steers.

  11. Bio-economic efficiency of supplementation for steers in Marandu Grass pasture

    Directory of Open Access Journals (Sweden)

    Daniel Marino Guedes de Carvalho

    2014-09-01

    Full Text Available The objective was to evaluate the effect of mineral salt (MS, multiple (MS, energy (ES and protein supplements (PS on performance, behavior and production cost of the cattle in Marandu grass pasture. The experiment lasted 84 days, conducted in the experimental area consists of four paddocks of 1.45 ha. Twenty steers were used with age and initial body weight of 172 kg and 10 months, respectively. It used a completely randomized design with four treatments and five replicate. The energy, multiple and protein supplements was supplied on 1.0 kg day-1. The animals were weighed at the beginning and end of the experiment, to determine the average daily gain (ADG. The weight gain of animals was 0.380, 0.600, 0.750 and 0.730 kg/day, respectively, for treatments MS, ES, MS and PS, have been verified statistical difference between supplemented animals and animals than received only mineral salt. The multiple supplement produced ADG 49.33% and 20.00% higher than the mineral salt. The multiple and protein supplements permitted average performance 18.92% higher than the energy supplement. There was no difference in behavior of grazing (P> 0.05. Animals receiving the mineral mixture had time to 8.40 hours of grazing animal day-1. The multiple supplement provided better economic performance considering the sale of animals to 350 kg body weight.

  12. Networks: structure and action : steering in and steering by policy networks

    NARCIS (Netherlands)

    Dassen, A.

    2010-01-01

    This thesis explores the opportunities to build a structural policy network model that is rooted in social network theories. By making a distinction between a process of steering in networks, and a process of steering by networks, it addresses the effects of network structures on network dynamics as

  13. Steering handbook

    CERN Document Server

    Pfeffer, Peter

    2017-01-01

    This edited volume presents basic principles as well as advanced concepts of the computational modeling of steering systems. Moreover, the book includes the components and functionalities of modern steering system, which are presented comprehensively and in a practical way. The book is written by more than 15 leading experts from the automotive industry and its components suppliers. The target audience primarily comprises practicing engineers, developers, researchers as well as graduate students who want to specialize in this field.

  14. 46 CFR 182.610 - Main steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Main steering gear. 182.610 Section 182.610 Shipping...) MACHINERY INSTALLATION Steering Systems § 182.610 Main steering gear. (a) A vessel must be provided with a main steering gear that is: (1) Of adequate strength and capable of steering the vessel at all service...

  15. Quantum steering in cascaded four-wave mixing processes.

    Science.gov (United States)

    Wang, Li; Lv, Shuchao; Jing, Jietai

    2017-07-24

    Quantum steering is used to describe the "spooky action-at-a-distance" nonlocality raised in the Einstein-Podolsky-Rosen (EPR) paradox, which is important for understanding entanglement distribution and constructing quantum networks. Here, in this paper, we study an experimentally feasible scheme for generating quantum steering based on cascaded four-wave-mixing (FWM) processes in hot rubidium (Rb) vapor. Quantum steering, including bipartite steering and genuine tripartite steering among the output light fields, is theoretically analyzed. We find the corresponding gain regions in which the bipartite and tripartite steering exist. The results of bipartite steering can be used to establish a hierarchical steering model in which one beam can steer the other two beams in the whole gain region; however, the other two beams cannot steer the first beam simultaneously. Moreover, the other two beams cannot steer with each other in the whole gain region. More importantly, we investigate the gain dependence of the existence of the genuine tripartite steering and we find that the genuine tripartite steering exists in most of the whole gain region in the ideal case. Also we discuss the effect of losses on the genuine tripartite steering. Our results pave the way to experimental demonstration of quantum steering in cascaded FWM process.

  16. Nutritional parameters of steers receiving different levels of sunflower crushed in partial replacement of soybean meal

    Directory of Open Access Journals (Sweden)

    HELLEN L. LIMA

    2013-10-01

    Full Text Available ABSTRACT To evaluate of the sunflower crushed in nutritional parameters in steers, supplemented at pasture, we used four steers in 4×4 Latin square design. The supplements were provided in 6 g/kg of body weight/animal/day, consisting of sunflower crushed, corn, soybean meal and mineral. All the supplements was isonitrogenous and soybean meal was replaced in 0, 20, 40, and 60% for sunflower crushed. The determination of ruminal pH and ammonia was at 0, 2, 4, 6 and 8 h. after feeding and for short-chain fatty acids it was collected at 0 and 6 h. post-feeding. The dry matter intake was not affected (P>0.05 by inclusion of sunflower crushed (mean=6.59 kg/day. There was no significant effect (P>0.05 for pH for the inclusion of sunflower crushed (mean=6.41. For contents of ruminal NH3-N was a significant effect (P <0.05 only for collection time, and ammonia peaks occurred between 2 and 4 h after feeding, with values of 22.56 and 21.40 mg/dL. The total concentration of short chain fatty acids and the C2:C3 ratio was reduced in 9.6 and 15.43%. The ruminal degradability of NDF was not affected by the supplements. The supplementation with sunflower crushed to beef steers grazing, in partial replacement of soybean meal did not alter nutrition parameters.

  17. Effect of sulfur content in wet or dry distillers grains fed at several inclusions on cattle growth performance, ruminal parameters, and hydrogen sulfide.

    Science.gov (United States)

    Sarturi, J O; Erickson, G E; Klopfenstein, T J; Vasconcelos, J T; Griffin, W A; Rolfe, K M; Benton, J R; Bremer, V R

    2013-10-01

    Effects of S from wet or dry distillers grains with solubles (DGS) containing 0.82 or 1.16% S on animal growth performance, carcass characteristics, apparent total tract digestibility, and ruminal parameters were evaluated. In Exp. 1, crossbred beef steers (n = 120; 345 ± 34 kg BW) were individually fed ad libitum using Calan gates. Treatments were applied as a 2 × 2 × 3 + 1 factorial treatment arrangement with factors of DGS type (wet or dry), S content in DGS (0.82 or 1.16% DM basis), and DGS inclusion (20, 30, and 40%, DM basis), as well as a corn control diet (no DGS). In Exp. 2, ruminally cannulated crossbred beef steers (n = 6; 381 ± 31 kg BW) were assigned to 1 of 5 diets in a 5 × 6 unbalanced Latin Square design and fed ad libitum through five 14-d periods. A 2 × 2 + 1 factorial treatment arrangement was used with the factors of DGS type and S content in DGS (similar to Exp. 1). Inclusion of DGS was 40%, except for a MATCH diet containing wet 1.16% S DGS included at 31.4% (DM basis). Intake of DM decreased linearly (P content (P = 0.52). Feeding diets with wet 1.16% S DGS linearly decreased (P = 0.03) HCW. In Exp. 2, molar proportion of propionate declined (P = 0.01) 9% and A:P ratio tended (P = 0.13) to be greater when 1.16 compared with 0.82% S DGS was fed. Apparent total tract DMD was not affected (P > 0.16) and only subtle changes (P ruminal pH parameters were observed. Greater (P = 0.02) ruminal H2S concentration for steers fed wet compared with dry DGS was observed, while 1.16% S DGS tended (P = 0.12) to produce greater ruminal H2S than 0.82% S. Sulfur in wet DGS appears to be more prone to be converted to ruminal H2S, because feeding 1.16% S as wet DGS had a greater impact on ADG, DMI, and ruminal H2S compared with dry DGS.

  18. Metagenomic Analysis of the Rumen Microbiome of Steers with Wheat-Induced Frothy Bloat.

    Science.gov (United States)

    Pitta, D W; Pinchak, W E; Indugu, N; Vecchiarelli, B; Sinha, R; Fulford, J D

    2016-01-01

    Frothy bloat is a serious metabolic disorder that affects stocker cattle grazing hard red winter wheat forage in the Southern Great Plains causing reduced performance, morbidity, and mortality. We hypothesize that a microbial dysbiosis develops in the rumen microbiome of stocker cattle when grazing on high quality winter wheat pasture that predisposes them to frothy bloat risk. In this study, rumen contents were harvested from six cannulated steers grazing hard red winter wheat (three with bloat score "2" and three with bloat score "0"), extracted for genomic DNA and subjected to 16S rDNA and shotgun sequencing on 454/Roche platform. Approximately 1.5 million reads were sequenced, assembled and assigned for phylogenetic and functional annotations. Bacteria predominated up to 84% of the sequences while archaea contributed to nearly 5% of the sequences. The abundance of archaea was higher in bloated animals (P bloated samples. Co-occurrence analysis revealed syntrophic associations between bacteria and archaea in non-bloated samples, however; such interactions faded in bloated samples. Functional annotations of assembled reads to Subsystems database revealed the abundance of several metabolic pathways, with carbohydrate and protein metabolism well represented. Assignment of contigs to CaZy database revealed a greater diversity of Glycosyl Hydrolases dominated by oligosaccharide breaking enzymes (>70%) in non-bloated samples. However, the abundance and diversity of CaZymes were greatly reduced in bloated samples indicating the disruption of carbohydrate metabolism. We conclude that mild to moderate frothy bloat results from tradeoffs both within and between microbial domains due to greater competition for substrates that are of limited availability as a result of biofilm formation.

  19. Multiobjective optimization of a steering linkage

    Energy Technology Data Exchange (ETDEWEB)

    Sleesonsom, S.; Bureerat, S. [Sustainable and Infrastructure Research and Development Center, Dept. of Mechanical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen (Thailand)

    2016-08-15

    In this paper, multi-objective optimization of a rack-and-pinion steering linkage is proposed. This steering linkage is a common mechanism used in small cars with three advantages as it is simple to construct, economical to manufacture, and compact and easy to operate. In the previous works, many researchers tried to minimize a steering error but minimization of a turning radius is somewhat ignored. As a result, a multi-objective optimization problem is assigned to simultaneously minimize a steering error and a turning radius. The design variables are linkage dimensions. The design problem is solved by the hybrid of multi-objective population-based incremental learning and differential evolution with various constraint handling schemes. The new design strategy leads to effective design of rack-and-pinion steering linkages satisfying both steering error and turning radius criteria.

  20. Multiobjective optimization of a steering linkage

    International Nuclear Information System (INIS)

    Sleesonsom, S.; Bureerat, S.

    2016-01-01

    In this paper, multi-objective optimization of a rack-and-pinion steering linkage is proposed. This steering linkage is a common mechanism used in small cars with three advantages as it is simple to construct, economical to manufacture, and compact and easy to operate. In the previous works, many researchers tried to minimize a steering error but minimization of a turning radius is somewhat ignored. As a result, a multi-objective optimization problem is assigned to simultaneously minimize a steering error and a turning radius. The design variables are linkage dimensions. The design problem is solved by the hybrid of multi-objective population-based incremental learning and differential evolution with various constraint handling schemes. The new design strategy leads to effective design of rack-and-pinion steering linkages satisfying both steering error and turning radius criteria

  1. 7 CFR 760.305 - Eligible grazing losses.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Eligible grazing losses. 760.305 Section 760.305... grazing losses. (a) A grazing loss due to drought is eligible for LFP only if the grazing loss for the... period for the specific type of grazing land or pastureland for the county.) (b) A grazing loss is not...

  2. Antagonism of lateral saphenous vein serotonin receptors from steers grazing endophyte-free, wild-type, or novel endophyte-infected tall fescue

    Science.gov (United States)

    Pharmacologic profiling of 5-hydroxytryptamine (5HT) receptors of bovine lateral saphenous vein has shown that cattle grazing endophyte-infected (Neotyphodium coenophialum) tall fescue (Lolium arundinaceum) have altered responses to ergovaline (ERV), 5HT, 5HT2A and 5HT7 agonists. To determine if 5HT...

  3. Steering and evasion assist

    NARCIS (Netherlands)

    Dang, T.; Desens, J.; Franke, U.; Gavrila, D.; Schäfers, L.; Ziegler, W.; Eskandarian, A.

    2012-01-01

    Steering and evasion assistance defines a new and future class of driver assistance systems to avoid an impending collision with other traffic participants. Dynamic and kinematic considerations reveal that an evasive steering maneuver has high potential for collision avoidance in many driving

  4. Improvement of motor inertia influence of electric power steering; Dendoshiki power steering no motor kansei no eikyo to hosho

    Energy Technology Data Exchange (ETDEWEB)

    Takehara, S; Sakamoto, K; Hanamoto, Y [Mazda Motor Corp., Hiroshima (Japan); Noritsugu, T [Okayama University, Okayama (Japan)

    1997-10-01

    Motor inertia of electric power steering affects not only steering characteristics but vehicle dynamics. We have investigated the influence of motor inertia and proposed a feedback strategy to compensate it. Weight of the test vehicle is 1100Kg and the steering system is pinion type electric power steering. By using simulation model and vehicle test, we have realized natural steering maneuvering and stable vehicle dynamics. 4 refs., 11 figs.

  5. Fundamental X-mode electron cyclotron current drive using remote-steering symmetric direction antenna at larger steering angles

    International Nuclear Information System (INIS)

    Idei, H.; Hanada, K.; Zushi, H.; Sato, K.N.; Sakamoto, M.; Iyomasa, A.; Kawasaki, S.; Nakashima, H.; Higashijima, A.; Ohkubo, K.; Kubo, S.; Shimozuma, T.; Ito, S.; Hasegawa, M.; Nakamura, K.; Notake, T.; Hoshika, H.; Maezono, N.; Nishi, S.; Nakashima, K.

    2005-01-01

    A remote steering antenna has been newly developed for Electron Cyclotron Heating and Current Drive (ECH/ECCD) experiments on the TRIAM-1M tokamak. It is a first application of the remote steering antenna to the ECH/ECCD experiments under the conditions relevant to International Thermonuclear Experimental Reactor. Our launcher is a symmetric direction antenna with extended steering capability. The larger steering angles of 8-19 degrees are available, in addition to that near 0 degree. The output beam from the antenna is the well-defined Gaussian beam with a correct steering angle. The Gaussian content and the steering angle accuracy are 0.85 and -0.3 degrees, respectively. Antenna transmission efficiency in the high power test is evaluated as 0.95. The efficiencies at the low and high power tests are consistent with those in the calculation with higher-order modes. The difference between plasma currents increased at co- and counter-steering injections [+/-19 degrees] is clearly observed in the superposition to the Lower Hybrid Current Driven (LHCD) plasma of the fundamental X-mode injection. (author)

  6. Modeling the grazing effect on dry grassland carbon cycling with modified Biome-BGC grazing model

    Science.gov (United States)

    Luo, Geping; Han, Qifei; Li, Chaofan; Yang, Liao

    2014-05-01

    Identifying the factors that determine the carbon source/sink strength of ecosystems is important for reducing uncertainty in the global carbon cycle. Arid grassland ecosystems are a widely distributed biome type in Xinjiang, Northwest China, covering approximately one-fourth the country's land surface. These grasslands are the habitat for many endemic and rare plant and animal species and are also used as pastoral land for livestock. Using the modified Biome-BGC grazing model, we modeled carbon dynamics in Xinjiang for grasslands that varied in grazing intensity. In general, this regional simulation estimated that the grassland ecosystems in Xinjiang acted as a net carbon source, with a value of 0.38 Pg C over the period 1979-2007. There were significant effects of grazing on carbon dynamics. An over-compensatory effect in net primary productivity (NPP) and vegetation carbon (C) stock was observed when grazing intensity was lower than 0.40 head/ha. Grazing resulted in a net carbon source of 23.45 g C m-2 yr-1, which equaled 0.37 Pg in Xinjiang in the last 29 years. In general, grazing decreased vegetation C stock, while an increasing trend was observed with low grazing intensity. The soil C increased significantly (17%) with long-term grazing, while the soil C stock exhibited a steady trend without grazing. These findings have implications for grassland ecosystem management as it relates to carbon sequestration and climate change mitigation, e.g., removal of grazing should be considered in strategies that aim to increase terrestrial carbon sequestrations at local and regional scales. One of the greatest limitations in quantifying the effects of herbivores on carbon cycling is identifying the grazing systems and intensities within a given region. We hope our study emphasizes the need for large-scale assessments of how grazing impacts carbon cycling. Most terrestrial ecosystems in Xinjiang have been affected by disturbances to a greater or lesser extent in the past

  7. Demand side management using profile steering

    NARCIS (Netherlands)

    Gerards, Marco Egbertus Theodorus; Toersche, Hermen; Hoogsteen, Gerwin; van der Klauw, Thijs; Hurink, Johann L.; Smit, Gerardus Johannes Maria

    2015-01-01

    Many Demand Side Management (DSM) approaches use energy prices as steering signals. This paper shows that such steering signals may result in power quality problems and high losses. As an alternative, this paper proposes to use desired (e.g., flat) power profiles as steering signals and presents an

  8. Experimental temporal quantum steering

    Czech Academy of Sciences Publication Activity Database

    Bartkiewicz, K.; Černoch, Antonín; Lemr, K.; Miranowicz, A.; Nori, F.

    2016-01-01

    Roč. 6, Nov (2016), 1-8, č. článku 38076. ISSN 2045-2322 R&D Projects: GA ČR GAP205/12/0382 Institutional support: RVO:68378271 Keywords : temporal quantum steering * EPR steering Subject RIV: BH - Optics, Masers, Lasers Impact factor: 4.259, year: 2016

  9. The grazing capacity of sweetveld: 2. A model to estimate grazing ...

    African Journals Online (AJOL)

    The relations between grazing capacity and three independent variables were investigated in the False Thornveld of the Eastern Cape. The variables were veld condition, rainfall and density of woody species. These relations were used to develop a preliminary model to assess grazing capacity in the veld type. Despite its ...

  10. 46 CFR 176.814 - Steering systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering systems. 176.814 Section 176.814 Shipping COAST...) INSPECTION AND CERTIFICATION Material Inspections § 176.814 Steering systems. At each initial and subsequent inspection for certification the owner or managing operator shall be prepared to test the steering systems of...

  11. Effects of a blended garlic and cinnamon essential oil extract with and without monensin sodium on the performance of grazing steers

    Science.gov (United States)

    A series of stocker grazing experiments were conducted with the objective to determine the efficacy of supplementing growing calf diets with essential oils from garlic and cinnamon extracts (GCOE) in promoting growth on cool-season annuals in Arkansas (SWREC) and Oklahoma (SPRRS), or native rangelan...

  12. Performance, profitability and greenhouse gas emissions of alternative finishing strategies for Holstein-Friesian bulls and steers.

    Science.gov (United States)

    Murphy, B; Crosson, P; Kelly, A K; Prendiville, R

    2018-02-06

    Modifying finishing strategies within established production systems has the potential to increase beef output and farm profit while reducing greenhouse gas (GHG) emissions. Thus, the objectives of this study were to investigate the effects of finishing duration on animal performance of Holstein-Friesian (HF) bulls and steers and evaluate the profitability and GHG emissions of these finishing strategies. A total of 90 HF calves were assigned to a complete randomised block design; three bull and three steer finishing strategies. Calves were rotationally grazed in a paddock system for the first season at pasture, housed and offered grass silage ad libitum plus 1.5 kg DM of concentrate per head daily for the first winter and returned to pasture for a second season. Bulls were slaughtered at 19 months of age and either finished indoors on concentrates ad libitum for 100 days (19AL), finished at pasture supplemented with 5 kg DM of concentrate per head daily for 100 (19SP) or 150 days (19LP). Steers were slaughtered at 21 months of age and finished at pasture, supplemented with 5 kg DM of concentrate per head daily for 60 (21SP) and 110 days (21LP) or slaughtered at 24 months of age and finished indoors over the second winter on grass silage ad libitum plus 5 kg DM of concentrate per head daily (24MO). The Grange Dairy Beef Systems Model and the Beef Systems Greenhouse Gas Emissions Model were used to evaluate profitability and GHG emissions, respectively. Average daily gain during the finishing period (Pprofit.

  13. The Effect of Different Type of Herbivores, Grazing Types and Grazing Intensities on Alpine Basiphillous Vegetation of the Romanian Carpathians

    Science.gov (United States)

    Ballová, Zuzana; Pekárik, Ladislav; Šibík, Jozef

    2017-04-01

    The major purpose of the present study was to test the hypothesis that there are significant differences in vegetation structure, plant species composition, and soil chemical properties in relation to type of grazing animals, various levels of grazing intensity and grazing type, and if potential differences alter with ecosystem productivity (increase in more productive ecosystems). The study was conducted in three mountain ranges of the Romanian Carpathians with a predominance of alkaline substrates (the Bucegi Mts, the Little Retezat Mts and the Ceahlău Massif). Statistical analyses were performed in R statistical software environment. The effects of grazing animals (cattle, horses and sheep), grazing types (fence, regular, irregular) and grazing intensity (low, medium, high) on the community structure were tested using ordination methods. In the case of soil properties, General Linear Mixed Model was applied. Special statistical approach eliminated the differences between the examined mountains and sites. Type of grazing animal does not significantly influence species cover but it is related to specific species occurrence. According to our results, grazing horses had similar effects as cattle compared to sheep. Grazing in restricted areas (surrounded by fence) and regular unrestricted grazing were more similar if compared to irregular grazing. When comparing the intensity of grazing, high and medium intensity were more similar to each other than to the low intensity grazing. Cattle grazed sites had significantly higher lichens cover, while the sheep patches were covered with increased overall herb layer (forbs, graminoids and low shrubs together). Medium grazing intensity decreased the lichens cover, cover of overall herb layer, and total vegetation cover compared to high and low grazing intensity. Grazing type had important impact on the lichens cover and cover of overall herb layer. The lichens cover appeared to decrease while the cover of overall herb layer

  14. Effect of early weaning and concentrate supplementation at forage intake and ingestive behavior of sheep grazing Tifton 85 (Cynodon spp.

    Directory of Open Access Journals (Sweden)

    Marina Gabriela Berchiol da Silva

    2012-12-01

    Full Text Available The objective of this study was to evaluate then early weaning and concentrate supplementation effect at pasture characteristics, forage intake and ingestive behavior of lambs grazing Tifton 85 (Cynodon spp.. A randomized block design was used with four treatments, three replications and five lambs per replicate. A total of 60 Suffolk lambs, that 36 were females and 24 steers. The treatments had corresponded to the combinations between early weaning precocious and concentrate supplementation strategies, that resulted in the following ones finishing systems: 1 lambs kept with mothers without supplementation; 2 lambs kept with mothers supplemented with concentrate in creep feeding at 2% of body weigh (BW in DM/day; 3 weaned lambs at 45 ± 5 days without supplementation and 4 weaned lambs at 45 ± 5 days and supplemented with concentrate at 2% of BW in DM/day. Grazing utilization method was continuous stocking with adjustment every 21 days, to maintain forage offer at 12% of BW in DM/day. To characterize the pastoral environment was assessed: morphological composition of pasture. There were made four observations the behavioral activities for individually lambs per 24 hours, such as: grazing, ruminating, suckling, supplementation, and others activities. The intake rate was measured using the technique of double sampling and determination of bite rate was made by visual observation of the number of bits made for animal. The behavior and the distribution of daily activities made by the lambs are influenced for the strategies evaluated. The exclusive presence of milk or supplement concentrate in the diet are important modulators of grazing activity, and the absence of these nutrient sources were offset per an increase in grazing time. This response considered the decrease in nutritional support and lower efficiency in harvesting the forage by lambs. The weaning influenced the morphological characteristics of the pasture, which showed favored the

  15. Beam Steering Devices Reduce Payload Weight

    Science.gov (United States)

    2012-01-01

    Scientists have long been able to shift the direction of a laser beam, steering it toward a target, but often the strength and focus of the light is altered. For precision applications, where the quality of the beam cannot be compromised, scientists have typically turned to mechanical steering methods, redirecting the source of the beam by swinging the entire laser apparatus toward the target. Just as the mechanical methods used for turning cars has evolved into simpler, lighter, power steering methods, so has the means by which researchers can direct lasers. Some of the typical contraptions used to redirect lasers are large and bulky, relying on steering gimbals pivoted, rotating supports to shift the device toward its intended target. These devices, some as large and awkward as a piece of heavy luggage, are subject to the same issues confronted by mechanical parts: Components rub, wear out, and get stuck. The poor reliability and bulk not to mention the power requirements to run one of the machines have made mechanical beam steering components less than ideal for use in applications where weight, bulk, and maneuverability are prime concerns, such as on an unmanned aerial vehicle (UAV) or a microscope. The solution to developing reliable, lighter weight, nonmechanical steering methods to replace the hefty steering boxes was to think outside the box, and a NASA research partner did just that by developing a new beam steering method that bends and redirects the beam, as opposed to shifting the entire apparatus. The benefits include lower power requirements, a smaller footprint, reduced weight, and better control and flexibility in steering capabilities. Such benefits are realized without sacrificing aperture size, efficiency, or scanning range, and can be applied to myriad uses: propulsion systems, structures, radiation protection systems, and landing systems.

  16. Operator space approach to steering inequality

    International Nuclear Information System (INIS)

    Yin, Zhi; Marciniak, Marcin; Horodecki, Michał

    2015-01-01

    In Junge and Palazuelos (2011 Commun. Math. Phys. 306 695–746) and Junge et al (2010 Commun. Math. Phys. 300 715–39) the operator space theory was applied to study bipartite Bell inequalities. The aim of the paper is to follow this line of research and use the operator space technique to analyze the steering scenario. We obtain a bipartite steering functional with unbounded largest violation of steering inequality, as well as constructing all ingredients explicitly. It turns out that the unbounded largest violation is obtained by a non maximally entangled state. Moreover, we focus on the bipartite dichotomic case where we construct a steering functional with unbounded largest violation of steering inequality. This phenomenon is different to the Bell scenario where only the bounded largest violation can be obtained by any bipartite dichotomic Bell functional. (paper)

  17. Simulating grazing practices in a complete livestock system model: estimating soil carbon storage and greenhouse gas emissions in grazed versus un-grazed agroecosystems using the Manure-DNDC model

    Science.gov (United States)

    Campbell, E. E.; Dorich, C.; Contosta, A.; Varner, R. K.

    2017-12-01

    In livestock agroecosystems, the combined contributions of enteric fermentation, manure management, and livestock grazing and/or feed production play an important role in agroecosystem carbon (C) storage and GHG losses, with complete livestock system models acting as important tools to evaluate the full impacts of these complex systems. The Manure-DeNitrification-DeComposition (DNDC) model is one such example, simulating impacts on C and nitrogen cycling, estimating methane, carbon dioxide, nitrous oxide, and ammonium dynamics in fields, manure storage, and enteric emissions. This allows the evaluation of differences in GHG and soil C impacts between conventional and organic dairy production systems, which differ in their use of grazed pasture versus confined feeding operations. However, Manure-DNDC has received limited testing in representing variations in grazed pasture management (i.e. intensive rotational grazing versus standard grazing practices). Using a set of forage biomass, soil C, and GHG emissions data collected at four sites across New England, we parameterized and validated Manure-DNDC estimations of GHG emissions and soil C in grazed versus un-grazed systems. Soil observations from these sites showed little effect from grazing practices, but larger soil carbon differences between farms. This may be due to spatial variation in SOC, making it difficult to measure and model, or due to controls of edaphic properties that make management moot. However, to further address these questions, model development will be needed to improve Manure-DNDC simulation of rotational grazing, as high stocking density grazing over short periods resulted in forage not re-growing sufficiently within the model. Furthermore, model simulations did not account for variation in interactions between livestock and soil given variability in field microclimates, perhaps requiring simulations that divide a single field into multiple paddocks to move towards more accurate evaluation of

  18. Driver behavior following an automatic steering intervention.

    Science.gov (United States)

    Fricke, Nicola; Griesche, Stefan; Schieben, Anna; Hesse, Tobias; Baumann, Martin

    2015-10-01

    The study investigated driver behavior toward an automatic steering intervention of a collision mitigation system. Forty participants were tested in a driving simulator and confronted with an inevitable collision. They performed a naïve drive and afterwards a repeated exposure in which they were told to hold the steering wheel loosely. In a third drive they experienced a false alarm situation. Data on driving behavior, i.e. steering and braking behavior as well as subjective data was assessed in the scenarios. Results showed that most participants held on to the steering wheel strongly or counter-steered during the system intervention during the first encounter. Moreover, subjective data collected after the first drive showed that the majority of drivers was not aware of the system intervention. Data from the repeated drive in which participants were instructed to hold the steering wheel loosely, led to significantly more participants holding the steering wheel loosely and thus complying with the instruction. This study seems to imply that without knowledge and information of the system about an upcoming intervention, the most prevalent driving behavior is a strong reaction with the steering wheel similar to an automatic steering reflex which decreases the system's effectiveness. Results of the second drive show some potential for countermeasures, such as informing drivers shortly before a system intervention in order to prevent inhibiting reactions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Solubility of plutonium and americium-241 from rumen contents of cattle grazing on plutonium-contaminated desert vegetation in in vitro bovine gastrointestinal fluids - August 1975 to January 1977

    International Nuclear Information System (INIS)

    Barth, J.; Giles, K.R.; Brown, K.W.

    1985-01-01

    The alimentary solubility of plutonium and americium-241 ingested by cattle grazing at Area 13 of the Nevada Test Site and the Clean Slate II site on the Tonopah Test Range in Nevada was studied in a series of experiments. For each experiment, or trial, rumen contents collected from a fistulated steer or a normal animals at the time of sacrifice were incubated in simulated bovine gastrointestinal fluids, and the solubility of plutonium and americium was analyzed following the abomasal, duodenal, jejunal, and lower intestinal digestive states. For Area 13, the peak plutonium-238 solubilities ranged from 1.09 to 9.60 percent for animals grazing in the inner enclosure that surrounds ground zero (GZ); for animals grazing in the outer enclosure, the peaks ranged from 1.86 to 18.46%. The peak plutonium-239 solubilities ranged from 0.71 to 4.81% for animals from the inner enclosure and from 0.71 to 3.61% for animals from the outer enclosure. Plutonium-238 was generally more soluble than plutonium-239. Plutonium ingested by cattle grazing in the outer enclosure was usually more soluble than plutonium ingested by cattle grazing in the inner enclosure. The highest concentrations of plutonium in the rumen contents of cattle grazing in the inner enclosure were found in trials conducted during August and November 1975 and January 1976. These concentrations decreased during the February, May, and July 1976 trials. The decrease was followed by an increase in plutonium concentration during the November 1976 trial. The concentration of americium-241 followed the same trend. 13 references, 13 tables

  20. Biogas production from steer manures in Vietnam

    DEFF Research Database (Denmark)

    Pham, Cuong H.; Saggar, Surinder; Vu, Cuong C.

    2017-01-01

    manures collected from two different experiments of steers fed diets containing feed supplements. BMP was 110.1 (NLkg-1 VS) for manure from steers receiving a control diet, significantly lower 79.0 (NL kg-1 VS) for manure from steers fed a diet containing 0.3% tannin (%DM), but then showed an increasing...... trend to 90.9 and 91.2 (NL kg-1 VS) for manures from steers receiving 0.4 and 0.5% tannin (%DM) supplements, respectively. Similarly, the CH4 production (NL kg-1 VS) of manure from steers was 174 for control, 142 for control supplemented concentrate (C), 143 for control added rice straw treated...

  1. 25 CFR 166.307 - Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not...

    Science.gov (United States)

    2010-04-01

    ... § 166.307 Will the grazing capacity be increased if I graze adjacent trust or non-trust rangelands not... trust or non-trust rangeland in common with the permitted land. Grazing capacity will be established... 25 Indians 1 2010-04-01 2010-04-01 false Will the grazing capacity be increased if I graze...

  2. 46 CFR 108.641 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary steering...

  3. 36 CFR 293.7 - Grazing of livestock.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Grazing of livestock. 293.7...-PRIMITIVE AREAS § 293.7 Grazing of livestock. (a) The grazing of livestock, where such use was established..., shall be permitted to continue under the general regulations covering grazing of livestock on the...

  4. Analysis of Vehicle Steering and Driving Bifurcation Characteristics

    Directory of Open Access Journals (Sweden)

    Xianbin Wang

    2015-01-01

    Full Text Available The typical method of vehicle steering bifurcation analysis is based on the nonlinear autonomous vehicle model deriving from the classic two degrees of freedom (2DOF linear vehicle model. This method usually neglects the driving effect on steering bifurcation characteristics. However, in the steering and driving combined conditions, the tyre under different driving conditions can provide different lateral force. The steering bifurcation mechanism without the driving effect is not able to fully reveal the vehicle steering and driving bifurcation characteristics. Aiming at the aforementioned problem, this paper analyzed the vehicle steering and driving bifurcation characteristics with the consideration of driving effect. Based on the 5DOF vehicle system dynamics model with the consideration of driving effect, the 7DOF autonomous system model was established. The vehicle steering and driving bifurcation dynamic characteristics were analyzed with different driving mode and driving torque. Taking the front-wheel-drive system as an example, the dynamic evolution process of steering and driving bifurcation was analyzed by phase space, system state variables, power spectral density, and Lyapunov index. The numerical recognition results of chaos were also provided. The research results show that the driving mode and driving torque have the obvious effect on steering and driving bifurcation characteristics.

  5. 50 CFR 35.9 - Livestock grazing.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 6 2010-10-01 2010-10-01 false Livestock grazing. 35.9 Section 35.9... NATIONAL WILDLIFE REFUGE SYSTEM WILDERNESS PRESERVATION AND MANAGEMENT General Rules § 35.9 Livestock grazing. (a) The grazing of livestock, where established prior to the date of legislation which designates...

  6. Method of Controlling Steering of a Ground Vehicle

    Science.gov (United States)

    Dawson, Andrew D. (Inventor); Bluethmann, William J. (Inventor); Lee, Chunhao J. (Inventor); Vitale, Robert L. (Inventor); Guo, Raymond (Inventor); Atluri, Venkata Prasad (Inventor)

    2016-01-01

    A method of controlling steering of a vehicle through setting wheel angles of a plurality of modular electronic corner assemblies (eModules) is provided. The method includes receiving a driving mode selected from a mode selection menu. A position of a steering input device is determined in a master controller. A velocity of the vehicle is determined, in the master controller, when the determined position of the steering input device is near center. A drive mode request corresponding to the selected driving mode to the plurality of steering controllers is transmitted to the master controller. A required steering angle of each of the plurality of eModules is determined, in the master controller, as a function of the determined position of the steering input device, the determined velocity of the vehicle, and the selected first driving mode. The eModules are set to the respective determined steering angles.

  7. Effects of a long-term disturbance on arthropods and vegetation in subalpine wetlands: manifestations of pack stock grazing in early versus mid-season.

    Directory of Open Access Journals (Sweden)

    Jeffrey G Holmquist

    Full Text Available Conclusions regarding disturbance effects in high elevation or high latitude ecosystems based solely on infrequent, long-term sampling may be misleading, because the long winters may erase severe, short-term impacts at the height of the abbreviated growing season. We separated a long-term effects of pack stock grazing, manifested in early season prior to stock arrival, from b additional pack stock grazing effects that might become apparent during annual stock grazing, by use of paired grazed and control wet meadows that we sampled at the beginning and end of subalpine growing seasons. Control meadows had been closed to grazing for at least two decades, and meadow pairs were distributed across Sequoia National Park, California, USA. The study was thus effectively a landscape-scale, long-term manipulation of wetland grazing. We sampled arthropods at these remote sites and collected data on associated vegetation structure. Litter cover and depth, percent bare ground, and soil strength had negative responses to grazing. In contrast, fauna showed little response to grazing, and there were overall negative effects for only three arthropod families. Mid-season and long-term results were generally congruent, and the only indications of lower faunal diversity on mid-season grazed wetlands were trends of lower abundance across morphospecies and lower diversity for canopy fauna across assemblage metrics. Treatment x Season interactions almost absent. Thus impacts on vegetation structure only minimally cascaded into the arthropod assemblage and were not greatly intensified during the annual growing season. Differences between years, which were likely a response to divergent snowfall patterns, were more important than differences between early and mid-season. Reliance on either vegetation or faunal metrics exclusively would have yielded different conclusions; using both flora and fauna served to provide a more integrative view of ecosystem response.

  8. Effects of a long-term disturbance on arthropods and vegetation in subalpine wetlands: manifestations of pack stock grazing in early versus mid-season.

    Science.gov (United States)

    Holmquist, Jeffrey G; Schmidt-Gengenbach, Jutta; Haultain, Sylvia A

    2013-01-01

    Conclusions regarding disturbance effects in high elevation or high latitude ecosystems based solely on infrequent, long-term sampling may be misleading, because the long winters may erase severe, short-term impacts at the height of the abbreviated growing season. We separated a) long-term effects of pack stock grazing, manifested in early season prior to stock arrival, from b) additional pack stock grazing effects that might become apparent during annual stock grazing, by use of paired grazed and control wet meadows that we sampled at the beginning and end of subalpine growing seasons. Control meadows had been closed to grazing for at least two decades, and meadow pairs were distributed across Sequoia National Park, California, USA. The study was thus effectively a landscape-scale, long-term manipulation of wetland grazing. We sampled arthropods at these remote sites and collected data on associated vegetation structure. Litter cover and depth, percent bare ground, and soil strength had negative responses to grazing. In contrast, fauna showed little response to grazing, and there were overall negative effects for only three arthropod families. Mid-season and long-term results were generally congruent, and the only indications of lower faunal diversity on mid-season grazed wetlands were trends of lower abundance across morphospecies and lower diversity for canopy fauna across assemblage metrics. Treatment x Season interactions almost absent. Thus impacts on vegetation structure only minimally cascaded into the arthropod assemblage and were not greatly intensified during the annual growing season. Differences between years, which were likely a response to divergent snowfall patterns, were more important than differences between early and mid-season. Reliance on either vegetation or faunal metrics exclusively would have yielded different conclusions; using both flora and fauna served to provide a more integrative view of ecosystem response.

  9. 46 CFR 61.20-1 - Steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of Inspections...

  10. Epidemiological studies of parasitic gastrointestinal nematodes, cestodes and coccidia infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

    Directory of Open Access Journals (Sweden)

    D.M. Pfukenyi

    2007-09-01

    Full Text Available Between January 1999 and December 2000 faecal samples from 16 264 cattle at 12 dipping sites in the highveld and nine in the lowveld communal grazing areas of Zimbabwe were examined for gastrointestinal (GI nematode and cestodes eggs, and coccidia oocysts. Strongyle larvae were identified following culture of pooled faecal samples collected at monthly intervals. The effects of region, age, sex and season on the prevalence of GI nematodes, cestodes and coccidia were determined. Faecal egg and oocyst counts showed an overall prevalence of GI nematodes of 43 %, coccidia 19.8 % and cestodes 4.8 %. A significantly higher prevalence of infection with GI nematodes, cestodes and coccidia was recorded in calves (P < 0.01 than in adults. Pregnant and lactating cows had significantly higher prevalences than bulls, oxen and non-lactating (dry cows (P < 0.01. The general trend of eggs per gram (epg of faeces and oocysts per gram (opg of faeces was associated with the rainfall pattern in the two regions, with high epg and opg being recorded during the wet months. The most prevalent genera of GI nematodes were Cooperia, Haemonchus and Trichostrongylus in that order. Strongyloides papillosus was found exclusively in calves. Haemonchus was significantly more prevalent during the wet season than the dry season (P < 0.01. In contrast, Trichostrongylus was present in significantly (P < 0.01 higher numbers during the dry months than the wet months, while Cooperia and Oesophagostomum revealed no significant differences between the wet and dry season. These findings are discussed with reference to their relevance for strategic control of GI parasites in cattle in communal grazing areas of Zimbabwe.

  11. Relative entropy of steering: on its definition and properties

    International Nuclear Information System (INIS)

    Kaur, Eneet; Wilde, Mark M

    2017-01-01

    In Gallego and Aolita (2015 Phys. Rev . X 5 041008), the authors proposed a definition for the relative entropy of steering and showed that the resulting quantity is a convex steering monotone. Here we advocate for a different definition for relative entropy of steering, based on well grounded concerns coming from quantum Shannon theory. We prove that this modified relative entropy of steering is a convex steering monotone. Furthermore, we establish that it is uniformly continuous and faithful, in both cases giving quantitative bounds that should be useful in applications. We also consider a restricted relative entropy of steering which is relevant for the case in which the free operations in the resource theory of steering have a more restricted form (the restricted operations could be more relevant in practical scenarios). The restricted relative entropy of steering is convex, monotone with respect to these restricted operations, uniformly continuous, and faithful. (paper)

  12. Effects of nitrogen fertilization and grazing on the emission of nitrous oxide from grassland

    Energy Technology Data Exchange (ETDEWEB)

    Velthof, G.L.; Brader, A.B.; Oenema, O. [NMI, Dept. of Soil Science and Plant Nutrition, Wageningen Agricultural Univ. (Netherlands)

    1995-11-01

    In the Netherlands, managed grasslands are potentially a large source of nitrous oxide (N{sub 2}O), because of the large nitrogen (N) input and the relatively high ground water levels. To provide insight into the major factors that contribute to N{sub 2}O emission from grassland and to provide quantitative N{sub 2}O emission rates, a monitoring study was carried out on four sites, during March 1992 to March 1994. Fluxes of N{sub 2}O increased after N fertilizer application and grazing, especially during wet conditions. Fluxes were higher from peat soils than from sand and clay soils. Fluxes were low during the winter periods. Total N{sub 2}O losses were 2 to 4.5 times higher on grassland fertilized with 160-460 kg N ha{sup -1} yr{sup -1} than on unfertilized grassland. Losses from grazed grasslands were 1.5 to 3.5 times higher than losses from mown grassland. This study shows that management practice of grassland and soil type are major factors controlling N{sub 2}O emission from grasslands. 2 figs., 3 refs.

  13. A study on electric properties for pulse laser annealing of ITO film after wet etching

    International Nuclear Information System (INIS)

    Lee, C.J.; Lin, H.K.; Li, C.H.; Chen, L.X.; Lee, C.C.; Wu, C.W.; Huang, J.C.

    2012-01-01

    The electric properties of ITO thin film after UV or IR laser annealing and wet etching was analyzed via grazing incidence in-plane X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectra and residual stress measurement. The laser annealing process readily induced microcracks or quasi-microcracks on the ITO thin film due to the residual tension stress of crystalline phase transformation between irradiated and non-irradiated areas, and these defects then became the preferred sites for a higher etching rate, resulting in discontinuities in the ITO thin film after the wet etching process. The discontinuities in the residual ITO thin film obstruct carrier transmission and further result in electric failure. - Highlights: ► The laser annealing process induces microcracks in InSnO 2 thin films. ► The defects result in higher local etching rate during wet etching. ► These process defects originate from residual tension stress. ► Decreasing the thermal shock is suggested in order to reduce these process defects.

  14. Wireless traffic steering for green cellular networks

    CERN Document Server

    Zhang, Shan; Zhou, Sheng; Niu, Zhisheng; Shen, Xuemin (Sherman)

    2016-01-01

    This book introduces wireless traffic steering as a paradigm to realize green communication in multi-tier heterogeneous cellular networks. By matching network resources and dynamic mobile traffic demand, traffic steering helps to reduce on-grid power consumption with on-demand services provided. This book reviews existing solutions from the perspectives of energy consumption reduction and renewable energy harvesting. Specifically, it explains how traffic steering can improve energy efficiency through intelligent traffic-resource matching. Several promising traffic steering approaches for dynamic network planning and renewable energy demand-supply balancing are discussed. This book presents an energy-aware traffic steering method for networks with energy harvesting, which optimizes the traffic allocated to each cell based on the renewable energy status. Renewable energy demand-supply balancing is a key factor in energy dynamics, aimed at enhancing renewable energy sustainability to reduce on-grid energy consum...

  15. Grass composition and rangeland condition of the major grazing ...

    African Journals Online (AJOL)

    One area represented lightly grazed government ranches or parks which were used as benchmarks, another area represented the seasonal grazing areas with an intermediate grazing pressure and the remaining were the heavily grazed roadsides, lakeshores and other communal grazing lands. The range condition ...

  16. Modelling nitrous oxide emissions from grazed grassland systems

    International Nuclear Information System (INIS)

    Wang Junye; Cardenas, Laura M.; Misselbrook, Tom H.; Cuttle, Steve; Thorman, Rachel E.; Li Changsheng

    2012-01-01

    Grazed grassland systems are an important component of the global carbon cycle and also influence global climate change through their emissions of nitrous oxide and methane. However, there are huge uncertainties and challenges in the development and parameterisation of process-based models for grazed grassland systems because of the wide diversity of vegetation and impacts of grazing animals. A process-based biogeochemistry model, DeNitrification-DeComposition (DNDC), has been modified to describe N 2 O emissions for the UK from regional conditions. This paper reports a new development of UK-DNDC in which the animal grazing practices were modified to track their contributions to the soil nitrogen (N) biogeochemistry. The new version of UK-DNDC was tested against datasets of N 2 O fluxes measured at three contrasting field sites. The results showed that the responses of the model to changes in grazing parameters were generally in agreement with observations, showing that N 2 O emissions increased as the grazing intensity increased. - Highlights: ► Parameterisation of grazing system using grazing intensity. ► Modification of UK D NDC for the UK soil and weather conditions. ► Validation of the UK D NDC against measured data of N 2 O emissions in three UK sites. ► Estimating influence of animal grazing practises on N 2 O emissions. - Grazing system was parameterised using grazing intensity and UK-DNDC model was modified and validated against measured data of N 2 O emissions in three UK sites.

  17. Lucerne varieties for continuous grazing

    DEFF Research Database (Denmark)

    Søegaard, Karen

    2012-01-01

    severe grazing with heifers in two cutting/grazing managements. Two new varieties, Verbena and Camporegio, and an older variety Luzelle were established in 2009 in pure stands and in two different mixtures with perennial ryegrass (Lolium perenne). Camporegio had the lowest yield, the lowest competitive...... strength, the lowest plant density in spring, and the density was most reduced during grazing. The results could not confirm significant differences between the new and the older varieties. The results for Luzelle were generally between Verbena and Camporegio. The varieties did not differ in herbage...

  18. Consumo, desempenho e parâmetros econômicos de novilhos Nelore e F1 Brangus x Nelore terminados em pastagens, suplementados com mistura mineral e sal nitrogenado com uréia ou amiréia Feed intake, performance and profitability of Nellore and crossbred (Brangus x Nellore steers finished in pastures, supplemented with mineralized salt and nitrogenous salt with urea or starea

    Directory of Open Access Journals (Sweden)

    L.C.V. Ítavo

    2008-04-01

    Full Text Available Avaliou-se o efeito da suplementação protéica (40% PB com amiréia ou uréia sobre o consumo de suplemento, desempenho e características econômicas de novilhos terminados em pastagens. Foram utilizados 120 novilhos com 19 meses de idade e 358kg, sendo 60 Nelore e 60 F1 Brangus x Nelore, divididos em três tratamentos com 20 animais, alojados em piquetes de Brachiaria brizantha cv. Marandu de 10 hectares cada, totalizando 120 hectares, sendo dois piquetes por grupo genético e tratamento, pastejados alternadamente a cada pesagem (42 dias. Os tratamentos consistiram em mistura mineral com amiréia-150S (AM, mistura mineral com uréia+milho+enxofre (UR e mistura mineral (MM. As médias de consumo de suplemento dos animais F1 foram de 206,1; 145,9 e 73,1g/dia, e as dos animais Nelore, 236,0; 205,1 e 94,3g/dia para os tratamentos AM, UR e MM, respectivamente. Para os novilhos Nelore, houve efeito (PThe effects of protein supplementation of finishing grazing steers by feeding nitrogenous salts (40% CP, urea or starea or mineralized salt only on supplement intake, growing performance and profitability were evaluated. One hundred and twenty steers (60 Nellore and 60 Brangus x Nellore, 19-month old, 358kg BW were divided in 12 equal groups which were allotted to one of 12 Brachiaria brizantha pastures (10-ha each performing two pastures for each breeding group and nutritional treatment. Groups were allowed to graze each pasture for 42 days when they were randomly moved into a new one. Nutritional treatments were as follow: MS - mineralized salt only; ST -mineralized salt plus starea - 150S; and UR - mineralized salt plus urea, corn and sulphur. UR supplement was prepared mixing the same ingredient contents of ST. Crossbred steers consumed 206.1; 145.9 and 73.1g/day whereas Nellore steers consumed 236.0; 205.11 and 94.29g/day of ST, UR and MS; respectively. For Nellore steers, UR increased slaughter weight (518.8kg compared to ST and MS (491.9 and

  19. Productivity of grasslands under continuous and rotational grazing

    NARCIS (Netherlands)

    Lantinga, E.A.

    1985-01-01

    In the Netherlands, rotational grazing, with grazing periods of 2 to 5 days, is the most common grazing system at present. In contrast with other countries of North-western Europe, the continuous grazing system is used here only to a limited extent. However, the results of numerous

  20. Automated beam steering using optimal control

    Energy Technology Data Exchange (ETDEWEB)

    Allen, C. K. (Christopher K.)

    2004-01-01

    We present a steering algorithm which, with the aid of a model, allows the user to specify beam behavior throughout a beamline, rather than just at specified beam position monitor (BPM) locations. The model is used primarily to compute the values of the beam phase vectors from BPM measurements, and to define cost functions that describe the steering objectives. The steering problem is formulated as constrained optimization problem; however, by applying optimal control theory we can reduce it to an unconstrained optimization whose dimension is the number of control signals.

  1. Effects of grazing strategy on limiting nitrate leaching in grazed grass-clover pastures on coarse sandy soil

    DEFF Research Database (Denmark)

    Hansen, Elly Møller; Eriksen, Jørgen; Søegaard, Karen

    2012-01-01

    -term mean. The experiment was initiated in a 4-yr-old grass-clover sward in south Denmark. Three treatments were as follows grazing only (G), spring cut followed by grazing (CG) and both spring and autumn cuts with summer grazing (CGC). Nitrate leaching was calculated by extracting water isolates from 80 cm......Urinations of ruminants on grazed pastures increase the risk of nitrate leaching. The study investigated the effect of reducing the length of the grazing season on nitrate leaching from a coarse sandy, irrigated soil during 2006–2007 and 2007–2008. In both years, precipitation was above the long...... depth using ceramic suction cups. Because of considerable variation in measured nitrate concentrations, the 32 installed suction cups per treatment were insufficient to reveal differences between treatments. However, weighted nitrate leaching estimations for G, CG and CGC showed estimated mean nitrate N...

  2. Speed choice and steering behavior in curve driving

    NARCIS (Netherlands)

    Winsum, W. van; Godthelp, J.

    1996-01-01

    The relation between speed choice and steering performance during curve negotiation was studied in a driving simulator. The hypothesis was that curve radius and steering competence both affect steering error during curve driving, resulting in compensatory speed choice. In this, the control of safety

  3. 46 CFR 58.25-20 - Piping for steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must be...

  4. Improving Einstein–Podolsky–Rosen steering inequalities with state information

    International Nuclear Information System (INIS)

    Schneeloch, James; Broadbent, Curtis J.; Howell, John C.

    2014-01-01

    We discuss the relationship between entropic Einstein–Podolsky–Rosen (EPR)-steering inequalities and their underlying uncertainty relations along with the hypothesis that improved uncertainty relations lead to tighter EPR-steering inequalities. In particular, we discuss how using information about the state of a quantum system affects one's ability to witness EPR-steering. As an example, we consider the recent improvement to the entropic uncertainty relation between pairs of discrete observables (Berta et al., 2010 [10]). By considering the assumptions that enter into the development of a steering inequality, we derive correct steering inequalities from these improved uncertainty relations and find that they are identical to ones already developed (Schneeloch et al., 2013 [9]). In addition, we consider how one can use state information to improve our ability to witness EPR-steering, and develop a new continuous variable symmetric EPR-steering inequality as a result.

  5. Grazing Affects Exosomal Circulating MicroRNAs in Cattle

    Science.gov (United States)

    Muroya, Susumu; Ogasawara, Hideki; Hojito, Masayuki

    2015-01-01

    Circulating microRNAs (c-miRNAs) are associated with physiological adaptation to acute and chronic aerobic exercise in humans. To investigate the potential effect of grazing movement on miRNA circulation in cattle, here we profiled miRNA expression in centrifugally prepared exosomes from the plasma of both grazing and housed Japanese Shorthorn cattle. Microarray analysis of the c-miRNAs resulted in detection of a total of 231 bovine exosomal miRNAs in the plasma, with a constant expression level of let-7g across the duration and cattle groups. Expression of muscle-specific miRNAs such as miR-1, miR-133a, miR-206, miR-208a/b, and miR-499 were undetectable, suggesting the mildness of grazing movement as exercise. According to validation by quantitative RT-PCR, the circulating miR-150 level in the grazing cattle normalized by the endogenous let-7g level was down-regulated after 2 and 4 months of grazing (P cattle equalized when the grazing cattle were returned to a housed situation. Likewise, the levels of miR-19b, miR-148a, miR-221, miR-223, miR-320a, miR-361, and miR-486 were temporarily lowered in the cattle at 1 and/or 2 month of grazing compared to those of the housed cattle (P cattle at 2 months of grazing (P = 0.044). The elevation of miR-451 level in the plasma was coincident with that in the biceps femoris muscle of the grazing cattle (P = 0.008), which suggests the secretion or intake of miR-451 between skeletal muscle cells and circulation during grazing. These results revealed that exosomal c-miRNAs in cattle were affected by grazing, suggesting their usefulness as molecular grazing markers and functions in physiological adaptation of grazing cattle associated with endocytosis, focal adhesion, axon guidance, and a variety of intracellular signaling, as predicted by bioinformatic analysis. PMID:26308447

  6. Livestock forage and mineral relations on a shrub-steppe rangeland in northwestern United States of America

    International Nuclear Information System (INIS)

    Uresk, D.W.; Rickard, W.H.

    1976-01-01

    The study area is the Arid Lands Ecology (ALE) Reserve, a portion of the United States Energy Research and Development Administration's Hanford Reservation located in the semi-arid region of south-central Washington. Small experimental pastures were subjected to four consecutive years of moderate spring grazing by yearling steers. These pastures are unique in that they represent grazing stresses imposed upon previously ungrazed (by livestock) plant communities. These communities had been protected from grazing by livestock for more than 30 years under ERDA management. Bluebunch wheatgrass (Agropyron spicatum), the dominant species, was the major forage plant in the diet of the steers during the 1974 grazing season, followed by Cusick's bluegrass (Poa cusickii), Thurber's needlegrass (Stipa thurberiania) and hawksbeard (Crepis atrabarba). These four species made up approximately 93% of the total diet. The forage intake ranged from 9.9 kg/head daily to 10.9 kg/head daily during the grazing season. During this period, these steers gained a total of 21.6 kg/ha live weight. Fifteen kg of forage consumed produces 1 kg of live steer for a 6.7% conversion. The conversion rate for crude protein was 12.7%, 83.3% for phosphorus and 25.6% for calcium. (author)

  7. Livestock grazing, wildlife habitat, and rangeland values

    Science.gov (United States)

    Paul R. Krausman; David E. Naugle; Michael R. Frisina; Rick Northrup; Vernon C. Bleich; William M. Block; Mark C. Wallace; Jeffrey D. Wright

    2009-01-01

    Livestock managers make and implement grazing management decisions to achieve a variety of objectives including livestock production, sustainable grazing, and wildlife habitat enhancement. Assessed values of grazing lands and ranches are often based on aesthetics and wildlife habitat or recreational values, which can exceed agricultural values, thus providing...

  8. Steer-by-wire innovations and demonstrator

    NARCIS (Netherlands)

    Lupker, H.A.; Zuurbier, J.; Verschuren, R.M.A.F.; Jansen, S.T.H.; Willemsen, D.M.C.

    2002-01-01

    Arguments for 'by-wire' systems include production costs, packaging and traffic safety. Innovations concern both product and development process e.g. combined virtual engineering and Hardware-in-the-loop testing. Three Steer-by-wire systems are discussed: a steering system simulator used as a

  9. Design and manufacturing of mechanical steering system for ...

    African Journals Online (AJOL)

    Design and manufacturing of mechanical steering system for parallel parking, zero turning radius, minimum turning radius with traditional turning. ... of the steering system are designed so as to meet all the configuration of steering system and to be well-matched to the power train, suspension system and body of the car.

  10. Research on Performance of Wire-controlled Hydraulic Steering System Based on Four-wheel Steering

    Science.gov (United States)

    Tao, P.; Jin, X. H.

    2018-05-01

    In this paper, the steering stability and control strategy of forklift are put forward. Drive based on yawing moment distribution of rotary torque coordination control method, through analyzing the linear two degree of freedom model of forklift truck, forklift yawing angular velocity and mass center side-slip Angle of expectations, as the control target parameters system, using fuzzy controller output driving forklift steering the yawing moment, to drive rotary torque distribution, make the forklift truck to drive horizontal pendulum angular velocity and side-slip Angle tracking reference model very well. In this paper, the lateral stability control system were designed, the joint simulation in MATLAB/Simulink, the simulation results show that under the different partial load, the control system can effectively to control side forklift lateral stability, enhanced the forklift driving safety, for the side forklift steering stability study provides a theoretical basis.

  11. 46 CFR 167.65-25 - Steering gear tests.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering gear tests. 167.65-25 Section 167.65-25... SHIPS Special Operating Requirements § 167.65-25 Steering gear tests. On all nautical school ships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means of...

  12. Quantum Steering Beyond Instrumental Causal Networks

    Science.gov (United States)

    Nery, R. V.; Taddei, M. M.; Chaves, R.; Aolita, L.

    2018-04-01

    We theoretically predict, and experimentally verify with entangled photons, that outcome communication is not enough for hidden-state models to reproduce quantum steering. Hidden-state models with outcome communication correspond, in turn, to the well-known instrumental processes of causal inference but in the one-sided device-independent scenario of one black-box measurement device and one well-characterized quantum apparatus. We introduce one-sided device-independent instrumental inequalities to test against these models, with the appealing feature of detecting entanglement even when communication of the black box's measurement outcome is allowed. We find that, remarkably, these inequalities can also be violated solely with steering, i.e., without outcome communication. In fact, an efficiently computable formal quantifier—the robustness of noninstrumentality—naturally arises, and we prove that steering alone is enough to maximize it. Our findings imply that quantum theory admits a stronger form of steering than known until now, with fundamental as well as practical potential implications.

  13. Assessment of a Boat Fractured Steering Wheel

    Directory of Open Access Journals (Sweden)

    Vukelic Goran

    2016-09-01

    Full Text Available During regular use of the steering wheel mounted on a boat, two cracks emanating from a fastener hole were noticed which, consequently, caused final fracture of the wheel. To determine the behavior of a boat steering wheel with cracks present, assessment of a fractured wheel was performed. Torque moments of the fasteners were measured prior to removing the steering wheel from the boat. Visual and dye penetrant inspection followed along with the material detection. Besides using experimental procedures, assessment of the fractured wheel was performed using finite element analysis, i.e. stress intensity factor values were numerically determined. Variation of stress intensity factor with crack length is presented. Possible causes of crack occurrence are given and they include excessive values of fastener torque moments coupled with fretting between fastener and fastener hole that was poorly machined. Results obtained by this assessment can be taken for predicting fracture behavior of a cracked steering wheel and as a reference in the design, mounting and exploitation process of steering wheels improving that way their safety in transportation environment.

  14. Holographic memory using beam steering

    Science.gov (United States)

    Chao, Tien-Hsin (Inventor); Hanan, Jay C. (Inventor); Reyes, George F. (Inventor); Zhou, Hanying (Inventor)

    2006-01-01

    A method, apparatus, and system provide the ability for storing holograms at high speed. A single laser diode emits a collimated laser beam to both write to and read from a photorefractice crystal. One or more liquid crystal beam steering spatial light modulators (BSSLMs) or Micro-Electro-Mechanical Systems (MEMS) mirrors steer a reference beam, split from the collimated laser beam, at high speed to the photorefractive crystal.

  15. Grazing function g and collimation angular acceptance

    Directory of Open Access Journals (Sweden)

    Stephen G. Peggs

    2009-11-01

    Full Text Available The grazing function g is introduced—a synchrobetatron optical quantity that is analogous (and closely connected to the Twiss and dispersion functions β, α, η, and η^{′}. It parametrizes the rate of change of total angle with respect to synchrotron amplitude for grazing particles, which just touch the surface of an aperture when their synchrotron and betatron oscillations are simultaneously (in time at their extreme displacements. The grazing function can be important at collimators with limited acceptance angles. For example, it is important in both modes of crystal collimation operation—in channeling and in volume reflection. The grazing function is independent of the collimator type—crystal or amorphous—but can depend strongly on its azimuthal location. The rigorous synchrobetatron condition g=0 is solved, by invoking the close connection between the grazing function and the slope of the normalized dispersion. Propagation of the grazing function is described, through drifts, dipoles, and quadrupoles. Analytic expressions are developed for g in perfectly matched periodic FODO cells, and in the presence of β or η error waves. These analytic approximations are shown to be, in general, in good agreement with realistic numerical examples. The grazing function is shown to scale linearly with FODO cell bend angle, but to be independent of FODO cell length. The ideal value is g=0 at the collimator, but finite nonzero values are acceptable. Practically achievable grazing functions are described and evaluated, for both amorphous and crystal primary collimators, at RHIC, the SPS (UA9, the Tevatron (T-980, and the LHC.

  16. Forage Quality and Grazing Performance of Beef Cattle Grazing Brown Mid-rib Grain Sorghum Residue

    Science.gov (United States)

    Residue from two grain sorghum hybrids, the control AWheatland x RTx430 (CON) and its near-isogenic hybrid containing the brown mid-rib gene bmr12 (BMR), were compared in a 2 year study. Forty-eight steers (236 ± 23 kg) in each year were assigned randomly to 2.12 ha paddocks (6 steers/paddock) cont...

  17. Steering Angle Function Algorithm of Morphing of Residential Area

    Directory of Open Access Journals (Sweden)

    XIE Tian

    2015-07-01

    Full Text Available A residential area feature morphing method based on steering angle function is presented. To residential area with the same representation under two different scales,transforming the representation of the residential area polygon from vector coordinates to steering angle function,then using the steering angle function to match,and finding out the similarity and the differences between the residential areas under different scale to get the steering angle function of the the residential areas under any middle scale,the final,transforming the middle scale steering angle function to vector coordinates form,and get the middle shape interpolation of the the residential area polygon.Experimental results show:the residential area morphing method by using steering angle function presented can realize the continuous multi-scale representation under the premise of keeping in shape for the residential area with the rectangular boundary features.

  18. Surface damage through grazing incidence ions investigated by scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Redinger, Alex

    2009-01-01

    Surface damage, caused by grazing incidence ions, is investigated with variable temperature scanning tunneling microscopy. The experiments are carried out on a Pt(111) crystal. The kinetic energy of noble gas ions is varied between 1-15 keV and the angle of incidence can be adjusted between θ = 78.5 and θ = 90 measured with respect to the surface normal. The damage patterns of single ion impacts, on flat terraces and at step edges of monoatomic height, are investigated at low surface temperatures. Ions hitting a flat terrace are usually specular reflected. The energy transfer from the ion to the crystal atoms is small and only little damage is produced. In contrast, at ascending step edges, which are illuminated by the ion beam, large angle scattering events occur. Sputtering, adatom and vacancy production is induced. However, a significant fraction of the ions, which hit step edges, enter the crystal and are guided in between two atomic layers parallel to the surface via small angle binary collisions. This steering process is denoted as subsurface channeling. The energy loss per length scale of the channeled particles is low, which results in long ion trajectories (up to 1000A). During the steering process, the ions produce surface damage. Depending on the ion species and the ion energy, adatom and vacancies or surface vacancy trenches of monoatomic width are observed. The surface damage can be used to track the path of the ion. This makes the whole trajectory of single ions with keV energy visible. The number of sputtered atoms per incident ion at ascending step edges, i.e. the step edge sputtering yield, is measured experimentally for different irradiation conditions. For θ = 86 , the sputtering yield is determined from the fluence dependent retraction of pre-existing illuminated step edges. An alternative method for the step edge sputtering yield determination, is the analysis of the concentration of ascending steps and of the removed amount of material as a

  19. Surface damage through grazing incidence ions investigated by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Redinger, Alex

    2009-07-10

    Surface damage, caused by grazing incidence ions, is investigated with variable temperature scanning tunneling microscopy. The experiments are carried out on a Pt(111) crystal. The kinetic energy of noble gas ions is varied between 1-15 keV and the angle of incidence can be adjusted between {theta} = 78.5 and {theta} = 90 measured with respect to the surface normal. The damage patterns of single ion impacts, on flat terraces and at step edges of monoatomic height, are investigated at low surface temperatures. Ions hitting a flat terrace are usually specular reflected. The energy transfer from the ion to the crystal atoms is small and only little damage is produced. In contrast, at ascending step edges, which are illuminated by the ion beam, large angle scattering events occur. Sputtering, adatom and vacancy production is induced. However, a significant fraction of the ions, which hit step edges, enter the crystal and are guided in between two atomic layers parallel to the surface via small angle binary collisions. This steering process is denoted as subsurface channeling. The energy loss per length scale of the channeled particles is low, which results in long ion trajectories (up to 1000A). During the steering process, the ions produce surface damage. Depending on the ion species and the ion energy, adatom and vacancies or surface vacancy trenches of monoatomic width are observed. The surface damage can be used to track the path of the ion. This makes the whole trajectory of single ions with keV energy visible. The number of sputtered atoms per incident ion at ascending step edges, i.e. the step edge sputtering yield, is measured experimentally for different irradiation conditions. For {theta} = 86 , the sputtering yield is determined from the fluence dependent retraction of pre-existing illuminated step edges. An alternative method for the step edge sputtering yield determination, is the analysis of the concentration of ascending steps and of the removed amount

  20. Ecological Effects of Grazing in the Northern Tianshan Mountains

    Directory of Open Access Journals (Sweden)

    Xiaotao Huang

    2017-11-01

    Full Text Available Identifying the effects of grazing is critical for the conservation, protection and sustainable use of arid grassland ecosystems. However, research regarding the ecological effects of grazing along mountainous elevation gradients is limited in arid areas, particularly at the regional scale. Using the Biome-BGC grazing model, we explored the effects of grazing on grassland net primary productivity (NPP, evapotranspiration (ET and water use efficiency (WUE from 1979 to 2012 along an elevation gradient in the northern Tianshan Mountains. The NPP, ET and WUE values were generally lower under the grazing scenario than under the ungrazed scenario; the differences between the grazing and ungrazed scenarios showed increasing trends over time; and distinct spatial heterogeneity in these differences was observed. Distinct decreases in NPP and WUE under the grazing scenario mainly occurred in regions with high livestock consumption. The decrease in ET was greater in mountainous areas with high grazing intensity due to decreased transpiration and increased surface runoff. This study contributes to a better understanding of the ecological effects of grazing along an elevation gradient in the northern Tianshan Mountains and provides data to support the scientific management of grassland ecosystems.

  1. Avaliação do consumo e ganho de peso de novilhos em pastejo rotacionado de capim-elefante (Pennisetum purpureum, Schum. cv. Napier, na estação chuvosa Evaluation of intake and weight gain of steers in rotacional grazing of elephantgrass (Pennisetum purpureum, Schum. cv. Napier, during the rainy season

    Directory of Open Access Journals (Sweden)

    Eleonora D'Avila Erbesdobler

    2002-09-01

    Full Text Available A pesquisa foi conduzida na Fazenda Experimental da EPAMIG-Leopoldina, MG, onde foram avaliados o consumo de capim-elefante, a efetividade da limitação do tempo de pastejo a quatro horas diárias, para manter o consumo próximo à mantença e o ganho de peso de 36 novilhos ¾ Gir-Holandês, em cinco períodos sucessivos de 36 dias, na estação chuvosa. Os tratamentos foram: livre acesso ao pasto (pastejo irrestrito e pastejo restrito. A disponibilidade de matéria verde seca do capim-elefante nos cinco períodos variou de 4,0 a 7,8 kg/100 kg PV. Os animais com livre acesso ao pasto consumiram o equivalente a 1,61 vezes o dos animais de pastejo restrito e tiveram ganho de peso de corpo vazio médio diário de 516,4 g, com um ganho estimado de 432,5 kg por hectare, estando dentro da faixa de ganho de peso verificada para capim-elefante no Brasil. O consumo de energia metabolizável por unidade de tamanho metabólico manteve-se estável nos três primeiros períodos, elevando-se nos dois últimos períodos, em que ocorreram os maiores ganhos de peso dos animais. Quatro horas diárias de pastejo garantiram consumo próximo à mantença.The research was conducted in the experimental farm of the EPAMIG-Leopoldina, MG, to evaluate intake of elephantgrass, the effectiveness of limiting grazing time to four daily hours for keeping intake close to maintenance level, and the weight gain of thirty-six steers during five successive periods of thirty-six days, during the rainy season. The treatments were: free access to pasture (unlimited grazing and restricted grazing. The availability of green dry matter varied from 4.0 to 7.8 kg/100kg LW. The average daily weight gain of animals with free access to pasture was 516.5 g and their dry matter intake corresponded to 1.61 times that from the restricted grazing ones. The estimated gain per hectare was 423.5 kg, which is within the range reported for elephantgrass in Brasil. Metabolizable energy intake, per

  2. 46 CFR 196.37-33 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Instructions for changing steering gear. 196.37-33... steering gear. (a) Instructions in at least 1/2 inch letters and figures shall be posted in the steering engineroom, relating in order, the different steps to be taken in changing to the emergency steering gear...

  3. 46 CFR 58.25-10 - Main and auxiliary steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Main and auxiliary steering gear. 58.25-10 Section 58.25... AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-10 Main and auxiliary steering gear. (a) Power-operated main and auxiliary steering gear must be separate systems that are independent throughout their...

  4. Steering Your Mysterious Mind

    DEFF Research Database (Denmark)

    Prasad, Ramjee

    Steering the Mysterious Mind, describes a unique, novel concept for a way to gain control of your mind. The five basic elements of human life, that is; Creativity, Content­ment, Confidence, Calmness, and Concentration (C5) have been introduced in my previous book Unlock Your Personalization. Posi....... Compare it with going to the gym where you work on the physical body. In the same way as with arms and legs, the mind is a mus­cle which you exercise through C5 practice. Steering the mind on your personal goal will help you to be creative....

  5. The grazing pattern of Muturu cattle under range system | Nweze ...

    African Journals Online (AJOL)

    Eighty Muturu cattle were grazed on rangeland, twice daily for two years to determine their grazing pattern. Twenty bulls and cows each between two to four years and forty calves between one to three months were used. The field grazing time (FGT), active grazing time (GT) and grazing travel time (GTT) were monitored.

  6. Working paper on public steering of privately owned sports facilities

    DEFF Research Database (Denmark)

    Iversen, Evald Bundgård

    This short paper discusses how municipalities can steer privately owned sports facilities. Firstly I analyse why steering of privately owned facilities is an interesting subject. Secondly I discuss what the advantages and drawbacks of using different approaches for steering sports facilities are........ Finally I discuss the methodological challenges of measuring activities in sports facilities – and take a closer look at the advantages and drawbacks of using manual and thermal techniques for registering activity.......This short paper discusses how municipalities can steer privately owned sports facilities. Firstly I analyse why steering of privately owned facilities is an interesting subject. Secondly I discuss what the advantages and drawbacks of using different approaches for steering sports facilities are...

  7. Ecology of grazing lawns in Africa

    CSIR Research Space (South Africa)

    Hempson, GP

    2014-09-01

    Full Text Available otherwise outcompete lawn species for light. Regular grazing that prevents shading and maintains sward quality is thus the cornerstone of grazing lawn dynamics. The strong interplay between abiotic conditions and disturbance factors, which are central...

  8. Carbon budgets for an irrigated intensively grazed dairy pasture and an unirrigated winter-grazed pasture

    Science.gov (United States)

    Hunt, John E.; Laubach, Johannes; Barthel, Matti; Fraser, Anitra; Phillips, Rebecca L.

    2016-05-01

    Intensification of pastoral agriculture is occurring rapidly across New Zealand, including increasing use of irrigation and fertiliser application in some regions. While this enables greater gross primary production (GPP) and livestock grazing intensity, the consequences for the net ecosystem carbon budget (NECB) of the pastures are poorly known. Here, we determined the NECB over one year for an irrigated, fertilised and rotationally grazed dairy pasture and a neighbouring unirrigated, unfertilised, winter-grazed pasture. Primary terms in the NECB calculation were: net ecosystem production (NEP), biomass carbon removed by grazing cows and carbon (C) input from their excreta. Annual NEP was measured using the eddy-covariance method. Carbon removal was estimated with plate-meter measurements calibrated against biomass collections, pre- and post-grazing. Excreta deposition was calculated from animal feed intake. The intensively managed pasture gained C (NECB = 103 ± 42 g C m-2 yr-1) but would have been subject to a non-significant C loss if cattle excreta had not been returned to the pasture. The unirrigated pasture was C-neutral (NECB = -13 ± 23 g C m-2 yr-1). While annual GPP of the former was almost twice that of the latter (2679 vs. 1372 g C m-2 yr-1), ecosystem respiration differed by only 68 % between the two pastures (2271 vs. 1352 g C m-2 yr-1). The ratio of GPP to the total annual water input of the irrigated pasture was 37 % greater than that of the unirrigated pasture, i.e. the former used the water input more efficiently than the latter to produce biomass. The NECB results agree qualitatively with those from many other eddy-covariance studies of grazed grasslands, but they seem to be at odds with long-term carbon-stock studies of other New Zealand pastures.

  9. How Insect Flight Steering Muscles Work

    OpenAIRE

    Walker, Simon M.; Schwyn, Daniel A.; Mokso, Rajmund; Wicklein, Martina; Müller, Tonya; Doube, Michael; Stampanoni, Marco; Krapp, Holger G.; Taylor, Graham K.

    2014-01-01

    Dipteran flies are amongst the smallest and most agile of flying animals. Their wings are driven indirectly by large power muscles, which cause cyclical deformations of the thorax that are amplified through the intricate wing hinge. Asymmetric flight manoeuvres are controlled by 13 pairs of steering muscles acting directly on the wing articulations. Collectively the steering muscles account for

  10. Observation of one-way Einstein-Podolsky-Rosen steering

    Science.gov (United States)

    Händchen, Vitus; Eberle, Tobias; Steinlechner, Sebastian; Samblowski, Aiko; Franz, Torsten; Werner, Reinhard F.; Schnabel, Roman

    2012-09-01

    The distinctive non-classical features of quantum physics were first discussed in the seminal paper by A. Einstein, B. Podolsky and N. Rosen (EPR) in 1935. In his immediate response, E. Schrödinger introduced the notion of entanglement, now seen as the essential resource in quantum information as well as in quantum metrology. Furthermore, he showed that at the core of the EPR argument is a phenomenon that he called steering. In contrast to entanglement and violations of Bell's inequalities, steering implies a direction between the parties involved. Recent theoretical works have precisely defined this property, but the question arose as to whether there are bipartite states showing steering only in one direction. Here, we present an experimental realization of two entangled Gaussian modes of light that in fact shows the steering effect in one direction but not in the other. The generated one-way steering gives a new insight into quantum physics and may open a new field of applications in quantum information.

  11. Herbage intake by grazing dairy cows

    NARCIS (Netherlands)

    Meijs, J.A.C.

    1981-01-01

    An extensive review of the literature is given of
    - nine possible methods for estimating herbage intake by grazing ruminants, with special attention to the sward-cutting and indirect animal methods
    - the factors determining the herbage intake by grazing ruminants.

    The

  12. Refractive waveguide non-mechanical beam steering (NMBS) in the MWIR

    Science.gov (United States)

    Myers, Jason D.; Frantz, Jesse A.; Spillmann, Christopher M.; Bekele, Robel Y.; Kolacz, Jakub; Gotjen, Henry; Naciri, Jawad; Shaw, Brandon; Sanghera, Jas S.

    2018-02-01

    Beam steering is a crucial technology for a number of applications, including chemical sensing/mapping and light detection and ranging (LIDAR). Traditional beam steering approaches rely on mechanical movement, such as the realignment of mirrors in gimbal mounts. The mechanical approach to steering has several drawbacks, including large size, weight and power usage (SWAP), and frequent mechanical failures. Recently, alternative non-mechanical approaches have been proposed and developed, but these technologies do not meet the demanding requirements for many beam steering applications. Here, we highlight the development efforts into a particular non-mechanical beam steering (NMBS) approach, refractive waveguides, for application in the MWIR. These waveguides are based on an Ulrich-coupled slab waveguide with a liquid crystal (LC) top cladding; by selectively applying an electric field across the liquid crystal through a prismatic electrode, steering is achieved by creating refraction at prismatic interfaces as light propagates through the device. For applications in the MWIR, we describe a versatile waveguide architecture based on chalcogenide glasses that have a wide range of refractive indices, transmission windows, and dispersion properties. We have further developed robust shadow-masking methods to taper the subcladding layers in the coupling region. We have demonstrated devices with >10° of steering in the MWIR and a number of advantageous properties for beam steering applications, including low-power operation, compact size, and fast point-to-point steering.

  13. Optimization Under Uncertainty for Wake Steering Strategies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Quick, Julian [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Annoni, Jennifer [National Renewable Energy Laboratory (NREL), Golden, CO (United States); King, Ryan N [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Dykes, Katherine L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Fleming, Paul A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ning, Andrew [Brigham Young University

    2017-05-01

    Wind turbines in a wind power plant experience significant power losses because of aerodynamic interactions between turbines. One control strategy to reduce these losses is known as 'wake steering,' in which upstream turbines are yawed to direct wakes away from downstream turbines. Previous wake steering research has assumed perfect information, however, there can be significant uncertainty in many aspects of the problem, including wind inflow and various turbine measurements. Uncertainty has significant implications for performance of wake steering strategies. Consequently, the authors formulate and solve an optimization under uncertainty (OUU) problem for finding optimal wake steering strategies in the presence of yaw angle uncertainty. The OUU wake steering strategy is demonstrated on a two-turbine test case and on the utility-scale, offshore Princess Amalia Wind Farm. When we accounted for yaw angle uncertainty in the Princess Amalia Wind Farm case, inflow-direction-specific OUU solutions produced between 0% and 1.4% more power than the deterministically optimized steering strategies, resulting in an overall annual average improvement of 0.2%. More importantly, the deterministic optimization is expected to perform worse and with more downside risk than the OUU result when realistic uncertainty is taken into account. Additionally, the OUU solution produces fewer extreme yaw situations than the deterministic solution.

  14. BEAMLINE-CONTROLLED STEERING OF SOURCE-POINT ANGLE AT THE ADVANCED PHOTON SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Emery, L.; Fystro, G.; Shang, H.; Smith, M.

    2017-06-25

    An EPICS-based steering software system has been implemented for beamline personnel to directly steer the angle of the synchrotron radiation sources at the Advanced Photon Source. A script running on a workstation monitors "start steering" beamline EPICS records, and effects a steering given by the value of the "angle request" EPICS record. The new system makes the steering process much faster than before, although the older steering protocols can still be used. The robustness features of the original steering remain. Feedback messages are provided to the beamlines and the accelerator operators. Underpinning this new steering protocol is the recent refinement of the global orbit feedback process whereby feedforward of dipole corrector set points and orbit set points are used to create a local steering bump in a rapid and seamless way.

  15. Bulling among yearling feedlot steers.

    Science.gov (United States)

    Pierson, R E; Jensen, R; Braddy, P M; Horton, D P; Christie, R M

    1976-09-01

    In a survey to determine the cause of illness and deaths among yearling feedlot cattle, bulling was found to be one of the major problems. During the years 1971-1974, 54,913 (2.88%) steers became bullers and represented an annual loss of around +325,000. Some of the causes of bulling were found to be hormones, either as implants or in the feed. In 1974, from 1,988 necropsies, it was determined that 83 steers died from riding injuries.

  16. Fault-tolerant Actuator System for Electrical Steering of Vehicles

    DEFF Research Database (Denmark)

    Sørensen, Jesper Sandberg; Blanke, Mogens

    2006-01-01

    is needed that meets this requirement. This paper studies the fault-tolerance properties of an electrical steering system. It presents a fault-tolerant architecture where a dedicated AC motor design used in conjunction with cheap voltage measurements can ensure detection of all relevant faults......Being critical to the safety of vehicles, the steering system is required to maintain the vehicles ability to steer until it is brought to halt, should a fault occur. With electrical steering becoming a cost-effective candidate for electrical powered vehicles, a fault-tolerant architecture...

  17. Methodologies for steering clocks

    Science.gov (United States)

    Chadsey, Harold

    1995-01-01

    One of the concerns of the PTTI community is the coordination of one time scale with another. This is accomplished through steering one clock system to another, with a goal of a zero or constant offset in time and frequency. In order to attain this goal, rate differences are calculated and allowed for by the steering algorithm. This paper will present several of these different methods of determining rate differences. Ideally, any change in rate should not cause the offset to change sign (overshoot) by any amount, but certainly not by as much as its previous absolute value. The advantages and disadvantages of each depend on the user's situation.

  18. Collective multipartite Einstein-Podolsky-Rosen steering: more secure optical networks.

    Science.gov (United States)

    Wang, Meng; Gong, Qihuang; He, Qiongyi

    2014-12-01

    Collective multipartite Einstein-Podolsky-Rosen (EPR) steering is a type of quantum correlation shared among N parties, where the EPR paradox of one party can only be realized by performing local measurements on all the remaining N-1 parties. We formalize the collective tripartite steering in terms of local hidden state model and give the steering inequalities that act as signatures and suggest how to optimize collective tripartite steering in specific optical schemes. The special entangled states with property of collective multipartite steering may have potential applications in ultra-secure multiuser communication networks where the issue of trust is critical.

  19. Directional control-response compatibility of joystick steered shuttle cars.

    Science.gov (United States)

    Burgess-Limerick, Robin; Zupanc, Christine M; Wallis, Guy

    2012-01-01

    Shuttle cars are an unusual class of vehicle operated in underground coal mines, sometimes in close proximity to pedestrians and steering errors may have very serious consequences. A directional control-response incompatibility has previously been described in shuttle cars which are controlled using a steering wheel oriented perpendicular to the direction of travel. Some other shuttle car operators are seated perpendicular to the direction of travel and steer the car via a seat mounted joystick. A virtual simulation was utilised to determine whether the steering arrangement in these vehicles maintains directional control-response compatibility. Twenty-four participants were randomly assigned to either a condition corresponding to this design (consistent direction), or a condition in which the directional steering response was reversed while driving in-bye (visual field compatible). Significantly less accurate steering performance was exhibited by the consistent direction group during the in-bye trials only. Shuttle cars which provide the joystick steering mechanism described here require operators to accommodate alternating compatible and incompatible directional control-response relationships with each change of car direction. A virtual simulation of an underground coal shuttle car demonstrates that the design incorporates a directional control-response incompatibility when driving the vehicle in one direction. This design increases the probability of operator error, with potential adverse safety and productivity consequences.

  20. Research on Handling Stability of Steering-by-wire System

    Directory of Open Access Journals (Sweden)

    Yuan Ying

    2017-01-01

    Full Text Available The main function of steer-by-wire (SBW system are improving steering characteristics, security and stability of the vehicle. In this paper, the variable steering ratio of SBW system is analyzed, and the method of steering ratio based on fuzzy control and neural network are researched. In order to solve the actual working condition, the wheel angle may not reach the expected value, this paper establishes a twodegree-of-freedom (2-DOF vehicle model, and a Matlab/Simulink simulation model, in which a control strategy based on PID controller is put forward to control the front wheel steering angle. Simulation results show that proposed control strategy based on fuzzy neural network can effectively reduce lateral deviation and improve the handling stability and comfortability of the vehicle.

  1. How Does “Hunger” Level Impact Grazing Behavior?

    Science.gov (United States)

    Grazing behavior can be influenced through feeding and grazing management decisions. Research at our USDA-ARS lab showed that ruminal fill, or how ‘hungry’ the cow is, can affect grazing behavior. Cows that had less ruminal fill took a bigger bite that was shallow and wide, compared to a ‘full’ cow ...

  2. Enhancing Soil Productivity Using a Multi-Crop Rotation and Beef Cattle Grazing

    Science.gov (United States)

    Şentürklü, Songül; Landblom, Douglas; Cihacek, Larry; Brevik, Eric

    2016-04-01

    Agricultural production systems that include complimentary plant, soil and animal interaction contribute to sustainability. In sustainable livestock systems integrated with crop production, the soil resource is impacted positively. The goal of this research was to maximize beef cattle and crop economic yield, while improving the soil resource by increasing soil organic matter (SOM) and subsequently seasonal soil nitrogen fertility over a 5-year period (2011-2015). Each experimental crop field used in the study was 1.74 ha. Small-seeded crops were planted using a JD 1590 No-Till drill. Corn (C) and sunflowers (SF) were planted using a JD 7000 No-Till planter. The cropping sequence used in the study was SF, hard red spring wheat (HRSW), fall seeded winter triticale-hairy vetch (T-HV), spring harvested for hay/mid-June seeded 7-species cover crop (CC; SF, Everleaf Oat, Flex Winter Pea, HV, Winfred Forage Rape, Ethiopian Cabbage, Hunter Leaf Turnip), C (85-day var.), and field pea-barley intercrop (PBY). The HRSW and SF were harvested as cash crops and the PBY, C, and CC were harvested by grazing cattle. In the system, yearling beef steers grazed PBY and unharvested C before feedlot entry, and after weaning, gestating cows grazed CC. Seasonal soil nitrogen fertility was measured at 0-15, 15-30, and 30-61 cm depths approximately every two weeks from June to October, 2014. The regression illustrating the relationship between SOM and average seasonal available mineral nitrogen shows that for each percentage increase in SOM there is a corresponding N increase of 1.47 kg/ha. Nitrogen fertilizer applications for the 5-year period of the study were variable; however, the overall trend was for reduced fertilizer requirement as SOM increased. At the same time, grain, oilseed, and annual forage crop yields increased year over year (2011-2015) except for the 2014 crop year, when above average precipitation delayed seeding and early frost killed the C and SF crops prematurely

  3. Annual methane budgets of sheep grazing systems were regulated by grazing intensities in the temperate continental steppe: A two-year case study

    Science.gov (United States)

    Ma, Lei; Zhong, Mengying; Zhu, Yuhao; Yang, Helong; Johnson, Douglas A.; Rong, Yuping

    2018-02-01

    Methane (CH4) emission from animal husbandry accounts for a large percentage of anthropogenic contributions to CH4 emissions. Fully understanding of grazing management effects on the CH4 budget is essential for mitigating CH4 emissions in the temperate grazing steppe systems. Annual CH4 budgets for the sheep grazed steppes at various grazing intensities, un-grazing (UG, 0 sheep ha-1year-1), defer grazing (DG, 1.0 sheep ha-1 year-1), moderate grazing (MG, 1.43 sheep ha-1year-1), and heavy grazing (HG, 2.43 sheep ha-1year-1) were assessed across 2012-2014 in the agro-pastoral region of northern China. Annual soil CH4 uptake averaged across 2012-2014 were 1.1 ± 0.1, 2.4 ± 0.2, 2.2 ± 0.2, and 1.3 ± 0.1 kg CH4-C ha-1 for UG, DG (only 2013-2014), MG and HG sites. Non-growing season CH4 uptake comprised 50.0 ± 4.3% of annual CH4 uptake in 2012-2013 and 37.7 ± 2.0% in 2013-2014. DG and MG significantly promoted annual soil CH4 uptake (P 0.05). Bell-shaped relationship was presented between stocking rates and soil CH4 uptake (r2 = 0.59, P budgets for the grazed grasslands were -1.1 ± 0.1, 5.7 ± 0.6, 11.5 ± 1.5 and 15.5 ± 1.3 kg CH4-C ha-1 year-1 in UG, DG (only 2013-2014), MG and HG across 2012-2014. Soil CH4 uptake could offset 29.7 ± 5.6, 15.9 ± 4.3 and 6.8 ± 1.0% of total annual CH4 emissions from sheep, sheepfold and faeces in DG, MG, and HG. All grazed steppes are sources for atmospheric CH4 and the magnitude is regulated by grazing intensities. Sheep CH4 emissions for 1-g liveweight gain were 0.21, 0.32 and 0.37 g CH4-C in DG, MG and HG, respectively. DG is the recommended grazing management in this region to achieve greater herbage mass, higher sheep performance and lower CH4 emissions simultaneously.

  4. 46 CFR 182.620 - Auxiliary means of steering.

    Science.gov (United States)

    2010-10-01

    ... TONS) MACHINERY INSTALLATION Steering Systems § 182.620 Auxiliary means of steering. (a) Except as... personnel hazards during normal or heavy weather operation. (b) A suitable hand tiller may be acceptable as...

  5. Livestock Grazing as a Driver of Vernal Pool Ecohydrology

    Science.gov (United States)

    Michaels, J.; McCarten, N. F.

    2017-12-01

    Vernal pools are seasonal wetlands that host rare plant communities of high conservation priority. Plant community composition is largely driven by pool hydroperiod. A previous study found that vernal pools grazed by livestock had longer hydroperiods compared with pools excluded from grazing for 10 years, and suggests that livestock grazing can be used to protect plant diversity. It is important to assess whether observed differences are due to the grazing or due to water balance variables including upland discharge into or out of the pools since no a priori measurements were made of the hydrology prior to grazing. To address this question, in 2016 we compared 15 pools that have been grazed continuously and 15 pools that have been fenced off for over 40 years at a site in Sacramento County. We paired pools based on abiotic characteristics (size, shape, slope, soil type) to minimize natural variation. We sampled vegetation and water depth using Solinst level loggers. We found that plant diversity and average hydroperiod was significantly higher in the grazed pools. We are currently measuring groundwater connectivity and upland inputs in order to compare the relative strength of livestock grazing as a driver of hydroperiod to these other drivers.

  6. Transitions and coexistence along a grazing gradient in the Eurasian steppe

    Science.gov (United States)

    Ren, Haiyan; Taube, Friedelm; Zhang, Yingjun; Bai, Yongfei; Hu, Shuijin

    2017-04-01

    Ecological resilience theory has often been applied to explain species coexistence and range condition assessment of various community states and to explicate the dynamics of ecosystems. Grazing is a primary disturbance that can alter rangeland resilience by causing hard-to-reverse transitions in grasslands. Yet, how grazing affects the coexistence of plant functional group (PFG) and transition remains unclear. We conducted a six-year grazing experiment in a typical steppe of Inner Mongolia, using seven grazing intensities (0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 sheep/ hectare) and two grazing systems (i.e. a continuous annual grazing as in the traditional grazing system, and a mixed grazing system combining grazing and haymaking), to examine grazing effects on plant functional group shifts and species coexistence in the semi-arid grassland system. Our results indicate that the relative richness of dominant bunchgrasses and forbs had a compensatory coexistence at all grazing intensities, and the richness of rhizomatous grasses fluctuated but was persistent. The relative productivity of dominant bunchgrasses and rhizomatous grasses had compensatory interactions with grazing intensity and grazing system. Dominant bunchgrasses and rhizomatous grasses resist grazing effects by using their dominant species functional traits: high specific leaf area and low leaf nitrogen content. Our results suggest that: 1. Stabilizing mechanisms beyond grazing management are more important in determining plant functional group coexistence and ecological resilience. 2. Plant functional group composition is more important in influencing ecosystem functioning than diversity. 3. Ecosystem resilience at a given level is related to the biomass of dominant PFG, which is determined by a balanced shift between dominant species biomass. The relatively even ecosystem resilience along the grazing gradient is attributed to the compensatory interactions of dominant species in their biomass variations

  7. Evaluating pasture and soil allowance of manganese for Kajli rams grazing in semi-arid environment.

    Science.gov (United States)

    Khan, Zafar Iqbal; Ahmad, Kafeel; Ashraf, Muhammad; Naqvi, Syed Ali Hassan; Seidavi, Alireza; Akram, Nudrat Aisha; Laudadio, Vito; Tufarelli, Vincenzo

    2015-03-01

    The current research on the manganese (Mn) transfer from soil to plant as well as to grazing Kajli rams in the form of sampling periods was carried out under semi-arid environmental conditions. Forage, soil and blood plasma samples were collected during 4 months of the year after a 1-month interval, and Mn concentrations were assessed after wet digestion using an atomic absorption spectrophotometer. Results showed that Mn concentration in soil ranged from 48.28 to 59.44 mg/kg, with incoherent augment and decline across sampling periods, and effect of sampling period on soil Mn was also found to be significant (P soil appeared higher than the critical value and sufficient for forage crop requirement. The Mn concentration in forage ranged between 24.8 and 37.2 mg/kg, resulting deficient based on the requirement allowance of Mn for livestock grazing animals, therein with almost unchanged forage Mn concentration. The Mn values in blood plasma of rams varied from 0.066 to 0.089 mg/l, with a consistent increase based on sampling period, and the effect of sampling periods on plasma Mn was found to be highly significant (P soil and plant species amassing capability on the transport of Mn in the soil-plant-animal system. Results indicated a much higher accumulation rate at the sampling characterized by vegetation dominated by legumes in comparison to grasses, crop residues and mixed pasture and a pronounced seasonal supply of Mn at the four sampling period of grazing land of diverse botanical composition.

  8. Modelling and Simulation of a Hydrostatic Steering System for Agricultural Tractors

    Directory of Open Access Journals (Sweden)

    Barbara Zardin

    2018-01-01

    Full Text Available The steering system of a vehicle impacts on the vehicle performance, safety and on the driver’s comfort. Moreover, in off-road vehicles using hydrostatic steering systems, the energy dissipation also becomes a critical issue. These aspects push and motivate innovation, research and analysis in the field of agricultural tractors. This paper proposes the modelling and analysis of a hydrostatic steering system for an agricultural tractor to calculate the performance of the system and determine the influence of its main design parameters. The focus here is on the driver’s steering feel, which can improve the driver’s behavior reducing unnecessary steering corrections during the working conditions. The hydrostatic steering system is quite complex and involves a hydraulic circuit and a mechanical mechanism to transmit the steering to the vehicle tires. The detailed lumped parameters model here proposed allows to simulate the dynamic behavior of the steering system and to both enhance the understanding of the system and to improve the design through parameters sensitivity analysis.

  9. Response of mountain meadows to grazing by recreational pack stock

    Science.gov (United States)

    Cole, David N.; Van Wagtendonk, Jan W.; McClaran, Mitchel P.; Moore, Peggy E.; McDougald, Neil K.

    2004-01-01

    Effects of recreational pack stock grazing on mountain meadows in Yosemite National Park were assessed in a 5-year study. Yosemite is a designated wilderness, to be managed such that its natural conditions are preserved. Studies were conducted in 3 characteristic meadow types: shorthair sedge (Carex filifolia Nutt.), Brewer's reed grass (Calamagrostis breweri Thurber), and tufted hairgrass [Deschampsia cespitosa (L.) Beauv.]. Horses and mules grazed experimental plots at intensities of 15 to 69% utilization for 4 seasons. In all 3 meadows, grazing caused decreases in productivity. The mean reduction after 4 years of grazing was 18% in the shorthair sedge meadow, 17% in the Brewer's reed grass meadow, and 22% in the tufted hairgrass meadow. Grazing also caused shifts in basal groundcover (usually a reduction in vegetation cover and increase in bare soil cover), and changes in species composition. Productivity and vegetation cover decreased as percent utilization increased, while bare soil cover increased as utilization increased. Changes in species composition were less predictably related to differences in grazing intensity. Passive management of grazing is insufficient in wilderness areas that are regularly used by groups with recreational stock. Wilderness managers need to monitor meadow conditions and the grazing intensities that occur. Our study suggests that biomass and ground cover are more sensitive indicators of grazing impact than species composition. Managers must make decisions about maximum acceptable levels of grazing impact and then develop guidelines for maximum use levels, based on data such as ours that relates grazing intensity to meadow response.

  10. Retrospective Review of Pectoralis Major Ruptures in Rodeo Steer Wrestlers

    Directory of Open Access Journals (Sweden)

    Breda H. F. Lau

    2013-01-01

    Full Text Available Background. Pectoralis major tendon ruptures have been reported in the literature as occupational injuries, accidental injuries, and sporting activities. Few cases have been reported with respect to rodeo activities. Purpose. To describe a series of PM tendon ruptures in professional steer wrestlers. Study Design. Case series, level of evidence, 4. Methods. A retrospective analysis of PM ruptures in a steer wrestling cohort was performed. Injury data between 1992 and 2008 were reviewed using medical records from the University of Calgary Sport Medicine Center. Results. Nine cases of pectoralis major ruptures in professional steer wrestlers were identified. Injuries occurred during the throwing phase of the steer or while breaking a fall. All athletes reported unexpected or abnormal behavior of the steer that contributed to the mechanism of injury. Seven cases were surgically repaired, while two cases opted for nonsurgical intervention. Eight cases reported successful return to competition following the injury. Conclusion. Steer wrestlers represent a unique cohort of PM rupture case studies. Steer wrestling is a demanding sport that involves throwing maneuvers that may predispose the muscle to rupture. All cases demonstrated good functional outcomes regardless of surgical or non-surgical treatment.

  11. Mineral supplementation for grazing ruminants

    International Nuclear Information System (INIS)

    McDowell, L.R.; Conrad, J.H.; Ellis, G.L.

    1986-01-01

    Grazing ruminants to which concentrate feeds cannot be economically fed must rely on self-feeding of mineral supplements. A number of factors affect mineral consumption of free-choice mixtures. Livestock exhibit little nutritional wisdom and will select palatable mixtures in preference to mixtures designed to meet their requirements. Palatability and appetite stimulators are often used to achieve a more uniform herd-wide consumption. It is best to formulate free-choice mixtures on the basis of analyses or other available data. However, when no information on mineral status is known, a free-choice complete mineral supplement is warranted. A 'complete' mineral mixture usually includes salt, a low fluoride P source, Ca, Co, Cu, I, Mn and Zn. Selenium, Mg, K, S, Fe or additional elements can be incorporated into a mineral supplement as new information suggests a need. The detriment to ruminant production caused by providing Ca, Se and Cu in excess can be greater than any benefit derived by providing a mineral supplement. In regions where high forage Mo predominates, three to five times the Cu content in mineral mixtures is needed to counteract Mo toxicity. Supplemental minerals are most critical during the wet season, when cattle are gaining weight rapidly and energy and protein supplies are adequate. Economic return on mineral supplementation is high. (author)

  12. The effect of grazing on cow mortality in Danish dairy herds

    DEFF Research Database (Denmark)

    Burow, Elke; Thomsen, Peter Thorup; Sørensen, Jan Tind

    2011-01-01

    The effect of summer grazing in large Danish dairy herds and certain management characteristics of grazing were studied for their impact on dairy cow mortality. Mortality data (from the Danish Cattle Database) from 391 Danish dairy herds (>100 cows) were combined with information from...... a questionnaire survey of grazing procedures on these herds in 2008. In all, 131 of the herds were identified as summer grazing and 260 as zero-grazing herds. The mortality was affected by an interaction of summer grazing and milking system. The risk of a cow dying was reduced to 46% in a grazing compared...... and pasture was associated with increased cow mortality....

  13. Woodlands Grazing Issues in Mediterranean Basin

    Science.gov (United States)

    Campos, P.

    2009-04-01

    In Mediterranean basin, woodlands grazing still continue to be important commercial owners' benefits. These owners manage woodlands vegetations as if they were not at risk of degradation and declining. Frequently, no temporally grazing set-aside is taken into account to avoid overgrazing of annual and perennial vegetations. Although less common, in the northern shore of Mediterranean basin undergrazing might increase the frequency and the number of catastrophic forest fires. This under/over grazing regime occurs in the Mediterranean basin woodlands with contrasted differences on land property rights, local economies and government livestock policy incentives. Spain and Tunisia are examples of these Mediterranean livestock contrasts. Most of Spanish Mediterranean woodlands and livestock herds are large private ownerships and owners could maintain their lands and livestock herds properties on the basis of moderate cash-income compensation against land revaluation and exclusive amenity self-consumption. The later is less tangible benefit and it could include family land legacy, nature enjoyment, country stile of life development, social status and so on. In public woodlands, social and environmental goals -as they are cultural heritage, biodiversity loss mitigation, soil conservation and employment- could maintain market unprofitable woodlands operations. Last three decades Spanish Mediterranean woodlands owners have increased the livestock herds incentivized by government subsidies. As result, grazing rent is pending on the level of European Union and Spanish government livestock subsidies. In this context, Spanish Mediterranean woodlands maintain a high extensive livestock stoking population, which economy could be called fragile and environmentally unsustainable because forest degradation and over/under grazing practices. Tunisian Mediterranean woodlands are state properties and livestock grazing is practice as a free private regimen. Livestock herds are small herd

  14. Grazing disturbance increases transient but decreases persistent soil seed bank.

    Science.gov (United States)

    Ma, Miaojun; Walck, Jeffrey L; Ma, Zhen; Wang, Lipei; Du, Guozhen

    2018-04-30

    Very few studies have examined whether the impacts of grazing disturbance on soil seed banks occur directly or indirectly through aboveground vegetation and soil properties. The potential role of the seed bank in alpine wetland restoration is also unknown. We used SEM (structural equation modeling) to explore the direct effect of grazing disturbance on the seed bank and the indirect effect through aboveground vegetation and soil properties. We also studied the role of the seed bank on the restoration potential in wetlands with various grazing intensities: low (fenced, winter grazed only), medium (seasonally grazed), and high (whole-year grazed). For the seed bank, species richness and density per plot showed no difference among grazing intensities for each depth (0-5, 5-10, 10-15 cm) and for the whole depth (0-15 cm) in spring and summer. There was no direct effect of grazing disturbance on seed bank richness and density both in spring and summer, and also no indirect effect on the seed bank through its direct effect on vegetation richness and abundance. Grazing disturbance indirectly increased spring seed bank density but decreased summer seed bank density through its direct effect (negative correlation) on soil moisture and total nitrogen and its indirect effect on vegetation abundance. Species composition of the vegetation changed with grazing regime, but that of the seed bank did not. An increased trend of similarity between the seed bank and aboveground vegetation with increased grazing disturbance was found in the shallow depth and in the whole depth only in spring. Although there was almost no change in seed bank size with grazing intensities, grazing disturbance increased the quantity of transient seeds but decreased persistent seeds. Persistent seeds stored in the soil could play a crucial role in vegetation regeneration and in restoration of degraded wetland ecosystems. The seed bank should be an integral part of alpine wetland restoration programs.

  15. Creation of quantum steering by interaction with a common bath

    Science.gov (United States)

    Sun, Zhe; Xu, Xiao-Qiang; Liu, Bo

    2018-05-01

    By applying the hierarchy equation method, we computationally study the creation of quantum steering in a two-qubit system interacting with a common bosonic bath. The calculation does not adopt conventional approximate approaches, such as the Born, Markov, rotating-wave, and other perturbative approximations. Three kinds of quantum steering, i.e., Einstein-Podolsky-Rosen steering (EPRS), temporal steering (TS), and spatiotemporal steering (STS), are considered. Since the initial state of the two qubits is chosen as a product state, there does not exist EPRS at the beginning. During the evolution, we find that STS as well as EPRS are generated at the same time. An inversion relationship between STS and TS is revealed. By varying the system-bath coupling strength from weak to ultrastrong regimes, we find the nonmonotonic dependence of STS, TS, and EPRS on the coupling strength. It is interesting to study the dynamics of the three kinds of quantum steering by using an exactly numerical method, which is not considered in previous researches.

  16. A review of experiments comparing systems of grazing management ...

    African Journals Online (AJOL)

    Experiments comparing different systems of grazing management on natural pastures in various parts of the world are reviewed. In experiments in which various rotational systems were tested against continuous grazing, fewer than half revealed pasture improvement relative to continuous grazing. In the majority of ...

  17. A theoretical model of speed-dependent steering torque for rolling tyres

    Science.gov (United States)

    Wei, Yintao; Oertel, Christian; Liu, Yahui; Li, Xuebing

    2016-04-01

    It is well known that the tyre steering torque is highly dependent on the tyre rolling speed. In limited cases, i.e. parking manoeuvre, the steering torque approaches the maximum. With the increasing tyre speed, the steering torque decreased rapidly. Accurate modelling of the speed-dependent behaviour for the tyre steering torque is a key factor to calibrate the electric power steering (EPS) system and tune the handling performance of vehicles. However, no satisfactory theoretical model can be found in the existing literature to explain this phenomenon. This paper proposes a new theoretical framework to model this important tyre behaviour, which includes three key factors: (1) tyre three-dimensional transient rolling kinematics with turn-slip; (2) dynamical force and moment generation; and (3) the mixed Lagrange-Euler method for contact deformation solving. A nonlinear finite-element code has been developed to implement the proposed approach. It can be found that the main mechanism for the speed-dependent steering torque is due to turn-slip-related kinematics. This paper provides a theory to explain the complex mechanism of the tyre steering torque generation, which helps to understand the speed-dependent tyre steering torque, tyre road feeling and EPS calibration.

  18. Milk production, grazing behavior and nutritional status of dairy cows grazing two herbage allowances during winter

    Directory of Open Access Journals (Sweden)

    Miguel Ruiz-Albarran

    2016-03-01

    Full Text Available Winter grazing provides a useful means for increasing the proportion of grazed herbage in the annual diet of dairy cows. This season is characterized by low herbage growth rate, low herbage allowance, and low herbage intake and hence greater needs for supplements to supply the requirements of lactating dairy cows. The aim of this study was to determine the influence of herbage allowance (HA offered to autumn calving dairy cows grazing winter herbage on milk production, nutritional status, and grazing behavior. The study took 63 d using 32 multiparous Holstein-Friesian dairy cows. Prior to experimental treatment, milk production averaged 20.2 ± 1.7 kg d-1, body weight was 503 ± 19 kg, and days in milking were 103 ± 6. Experimental animals were randomly assigned to two treatments according to HA offered above ground level: low (17 kg DM cow-1 d-1 vs. high HA (25 kg DM cow¹ d¹. All cows were supplemented with grass silage supplying daily 6.25 and 4.6 kg DM of concentrate (concentrate commercial plus high corn moisture. Decreasing HA influenced positively milk production (+25%, milk protein (+20 kg, and milk fat (+17 kg per hectare; however no effects on milk production per cow or energy metabolic status were observed in the cows. In conclusion, a low HA showed to be the most significant influencing factor on milk and milk solids production per hectare in dairy cows grazing restricted winter and supplemented with grass silage and concentrate; but no effect on the milk production per cow was found.

  19. Electronic differential control of 2WD electric vehicle considering steering stability

    Science.gov (United States)

    Hua, Yiding; Jiang, Haobin; Geng, Guoqing

    2017-03-01

    Aiming at the steering wheel differential steering control technology of rear wheel independent driving electric wheel, considering the assisting effect of electronic differential control on vehicle steering, based on the high speed steering characteristic of electric wheel car, the electronic differential speed of auxiliary wheel steering is also studied. A yaw moment control strategy is applied to the vehicle at high speed. Based on the vehicle stability reference value, yaw rate is used to design the fuzzy controller to distribute the driving wheel torque. The simulation results show that the basic electronic differential speed function is realized based on the yaw moment control strategy, while the vehicle stability control is improved and the driving safety is enhanced. On the other hand, the torque control strategy can also assist steering of vehicle.

  20. Development of active rear steer actuator. Development of four wheel steer actuator for active safety; Active rear steer actuator no kaihatsu. Yobo anzen ni muketa 4WS actuator no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yamanaka, T [Aisin Seiki Co. Ltd., Aichi (Japan)

    1997-10-01

    Recently, ecology, energy saving and safety have become important issues. And Active Safety is spotlighted in vehicle control area. Many researches and developments on four wheel steer system have been done to improve vehicle stability. We have developed the Active Rear Steer system with electromechanical Actuator, which is mass-productive, compact, and high response and durable. 10 figs., 5 tabs.

  1. Soil contamination of plant surfaces from grazing and rainfall interactions

    International Nuclear Information System (INIS)

    Hinton, T.G.; Stoll, J.M.; Tobler, L.

    1995-01-01

    Contaminants often attach to soil particles, and their subsequent environmental transport is largely determined by processes that govern soil movement. We examined the influence of grazing intensity on soil contamination of pastures. Four different grazing densities of sheep were tested against an ungrazed control plot. Scandium concentrations were determined by neutron activation analysis and was used as a tracer of soil adhesion on vegetation. Soil loadings ( g soil kg -1 dry plant) increased 60% when grazing intensity was increased by a factor of four (p 0.003). Rain and wind removed soil from vegetation in the ungrazed control plots, but when grazing sheep were present, an increase in rain from 0.3 to 9.7 mm caused a 130% increase in soil contamination. Multiple regression was used to develop an equation that predicts soil loadings as a function of grazing density, rainfall and wind speed (p = 0.0001, r 2 = 0.78). The model predicts that if grazing management were to be used as a tool to reduce contaminant intake from inadvertent consumption of resuspended soil by grazing animals, grazing densities would have to be reduced 2.5 times to reduce soil loadings by 50%. (author)

  2. 46 CFR 78.47-55 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Instructions for changing steering gear. 78.47-55... OPERATIONS Markings for Fire and Emergency Equipment, Etc. § 78.47-55 Instructions for changing steering gear..., relating in order, the different steps to be taken in changing to the emergency steering gear. Each clutch...

  3. Genuine Multipartite Einstein-Podolsky-Rosen Steering

    Science.gov (United States)

    He, Q. Y.; Reid, M. D.

    2013-12-01

    We develop the concept of genuine N-partite Einstein-Podolsky-Rosen (EPR) steering. This nonlocality is the natural multipartite extension of the original EPR paradox. Useful properties emerge that are not guaranteed for genuine multipartite entangled states. In particular, there is a close link with the task of one-sided, device-independent quantum secret sharing. We derive inequalities to demonstrate multipartite EPR steering for Greenberger-Horne-Zeilinger and Gaussian continuous variable states in loophole-free scenarios.

  4. Developmental instability and fitness in Periploca laevigata experiencing grazing disturbance

    Science.gov (United States)

    Alados, C.L.; Giner, M.L.; Dehesa, L.; Escos, J.; Barroso, F.; Emlen, J.M.; Freeman, D.C.

    2002-01-01

    We investigated the sensitivity of developmental instability measurements (leaf fluctuating asymmetry, floral radial asymmetry, and shoot translational asymmetry) to a long‐standing natural stress (grazing) in a palatable tannin‐producing shrub (Periploca laevigata Aiton). We also assessed the relationship between these measures of developmental instability and fitness components (growth and floral production). Developmental instability, measured by translational asymmetry, was the most accurate estimator of a plant’s condition and, consequently, environmental stress. Plants with less translational asymmetry grew more and produced more flowers. Plants from the medium‐grazed population were developmentally more stable, as estimated by translational and floral asymmetry, than either more heavily or more lightly grazed populations. Leaf fluctuating asymmetry was positively correlated with tannin concentration. The pattern of internode growth also responded to grazing impact. Plants under medium to heavy grazing pressure accelerated early growth and consequently escaped herbivory later in the season, i.e., at the beginning of the spring, when grazing activity was concentrated in herbaceous plants. Periploca laevigata accelerated growth and finished growing sooner than in the other grazing treatment. Thus, its annual growth was more mature and less palatable later in the season when grazers typically concentrate on shrubs. The reduction of developmental instability under medium grazing is interpreted as a direct effect of grazing and not as the release from competition.

  5. 46 CFR 97.37-33 - Instructions for changing steering gear.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 97.37-33... steering gear. (a) Instructions in at least 1/2 inch letters and figures shall be posted in the steering... gear. Each clutch, gear, wheel, lever, valve, or switch which is used during the changeover shall be...

  6. Applications of EPR steering in quantum teleportation and NOON states

    Science.gov (United States)

    Zárate, Laura Rosales

    2018-04-01

    Einstein-Podolsky-Rosen (EPR) steering refers to the type of correlations described in the EPR paradox, where one observer seems to affect ("steer") the state of other observer by using local measurements. There have been several works regarding characterization and quantification of EPR steering. One characteristic of this non-local correlation is that it can be asymmetric, while entanglement is symmetric. This asymmetric property is relevant for potential applications of EPR steering to quantum information, in particular to quantum cryptography and quantum teleportation. This latter refers to the process where one observer sends an unknown quantum state to Bob, who is in a different location. They communicate by classical means. Here we will show that EPR steering is a necessary resource to obtain secure continuous variable teleportation. We will also consider NOON states, which is an example of an entangled state. For this state, we will present a steering signature. This contribution reviews the work derived in Refs. [1] and [2], which was presented as an invited talk in ELAF 2017.

  7. Monogamy inequalities for the Einstein-Podolsky-Rosen paradox and quantum steering

    Science.gov (United States)

    Reid, M. D.

    2013-12-01

    Monogamy inequalities for the way bipartite Einstein-Podolsky-Rosen (EPR) steering can be distributed among N systems are derived. One set of inequalities is based on witnesses with two measurement settings, and may be used to demonstrate correlation of outcomes between two parties, that cannot be shared with more parties. It is shown that the monogamy for steering is directional. Two parties cannot independently demonstrate steering of a third system, using the same two-setting steering witness, but it is possible for one party to steer two independent systems. This result explains the monogamy of two-setting Bell inequality violations and the sensitivity of the continuous variable (CV) EPR criterion to losses on the steering party. We generalize to m settings. A second type of monogamy relation gives the quantitative amount of sharing possible, when the number of parties is less than or equal to m, and takes a form similar to the Coffman-Kundu-Wootters relation for entanglement. The results enable characterization of the tripartite steering for CV Gaussian systems and qubit Greenberger-Horne-Zeilinger and W states.

  8. Evaluation of flexible endoscope steering using haptic guidance

    NARCIS (Netherlands)

    Reilink, Rob; Stramigioli, Stefano; Kappers, Astrid M L; Misra, Sarthak

    Background: Steering the tip of a flexible endoscope relies on the physician's dexterity and experience. For complex flexible endoscopes, conventional controls may be inadequate. Methods: A steering method based on a multi-degree-of-freedom haptic device is presented. Haptic cues are generated based

  9. Evaluation of flexible endoscope steering using haptic guidance

    NARCIS (Netherlands)

    Reilink, Rob; Stramigioli, Stefano; Kappers, Astrid M.L.; Misra, Sarthak

    2011-01-01

    Background - Steering the tip of a flexible endoscope relies on the physician’s dexterity and experience. For complex flexible endoscopes, conventional controls may be inadequate. Methods - A steering method based on a multi-degree-of-freedom haptic device is presented. Haptic cues are generated

  10. Relação entre o genótipo e o temperamento de novilhos em pastejo e seu efeito na qualidade da carne Relation between genotype and temperament of grazing steers on meat quality

    Directory of Open Access Journals (Sweden)

    Isabella Dias Barbosa Silveira

    2006-04-01

    Full Text Available Avaliaram-se a interação grupo genético ' temperamento e seu efeito sobre a carne de bovinos de corte. Foram utilizados 40 novilhos machos castrados de dois grupos genéticos (Aberdeen Angus - AA e 50% Aberdeen Angus e 50% Nelore - NA, com dois anos de idade e peso inicial de 336,4 ± 29,39 kg, distribuídos em delineamento completamente casualizado. O temperamento foi avaliado por meio da atribuição de escores comportamentais (EC e mensuração do tempo de saída (TS. Os novilhos NA apresentaram os maiores EC. Os TS dos animais AA foram maiores que os dos NA nas avaliações 1 e 4 (2,1 x 1,3 e 4,7 x 2,3 segundos, respectivamente. O ganho médio de peso foi negativamente correlacionado ao ECm e positivamente ao TSm. No grupo genético NA, os animais mais reativos apresentaram menor ganho de peso e aqueles com EC mais altos, menores valores de pH1 (6,47; 6,28; e 6,09 para EC 1, 2 e 3, respectivamente. Os pH1 mais baixos foram verificados em animais com TS (6,10; 6,43; e 6,43 para TS 1, 2 e 3, respectivamente. Os animais NA apresentaram pH1 menor que os AA, com 6,17 e 6,57, respectivamente. A carne de novilhos NA com maiores TS foi superior em 23% para a cor a* (P=0,0394 e em 9% para a cor b* (P=0,0808. A cor L* se correlacionou negativamente com EC3 e pH24 (r=-0,54 e -0,39, respectivamente e a cor b*, com pH3 e pH7 (r =-0,39 e -0,45, respectivamente. Novilhos azebuados e mais agitados apresentam ganho de peso inferior e menores alterações quanto ao pH inicial e à cor da carne.The effect of two genetic groups, Aberdeen angus (AA and 50% Nellore x 50% Aberdeen angus (NA, on temperament and meat quality of 40 steers averaging 2 years of age and 336.4 ± 29.39 kg of body weight was evaluated in this trial. Animals were assigned to treatments according to a completely randomized design. Temperament was evaluated through measurements of composite behavior score (BS and flight time (FT. NA steers had higher BS than AA steers in this trial

  11. Altered steering strategies for goal-directed locomotion in stroke

    Science.gov (United States)

    2013-01-01

    Background Individuals who have sustained a stroke can manifest altered locomotor steering behaviors when exposed to optic flows expanding from different locations. Whether these alterations persist in the presence of a visible goal and whether they can be explained by the presence of a perceptuo-motor disorder remain unknown. The purpose of this study was to compare stroke participants and healthy participants on their ability to control heading while exposed to changing optic flows and target locations. Methods Ten participants with stroke (55.6 ± 9.3 yrs) and ten healthy controls (57.0 ± 11.5 yrs) participated in a mouse-driven steering task (perceptuo-motor task) while seated and in a walking steering task. In the seated steering task, participants were instructed to head or ‘walk’ toward a target in the virtual environment by using a mouse while wearing a helmet-mounted display (HMD). In the walking task, participants performed a similar steering task in the same virtual environment while walking overground at their comfortable speed. For both experiments, the target and/or the focus of expansion (FOE) of the optic flow shifted to the side (±20°) or remained centered. The main outcome measure was net heading errors (NHE). Secondary outcomes included mediolateral displacement, horizontal head orientation, and onsets of heading and head reorientation. Results In the walking steering task, the presence of FOE shifts modulated the extent and timing of mediolateral displacement and head rotation changes, as well as NHE magnitudes. Participants overshot and undershot their net heading, respectively, in response to ipsilateral and contralateral FOE and target shifts. Stroke participants made larger NHEs, especially when the FOE was shifted towards the non-paretic side. In the seated steering task, similar NHEs were observed between stroke and healthy participants. Conclusions The findings highlight the fine coordination between rotational and

  12. Demonstration of Multisetting One-Way Einstein-Podolsky-Rosen Steering in Two-Qubit Systems

    Science.gov (United States)

    Xiao, Ya; Ye, Xiang-Jun; Sun, Kai; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can

    2017-04-01

    Einstein-Podolsky-Rosen (EPR) steering describes the ability of one party to remotely affect another's state through local measurements. One of the most distinguishable properties of EPR steering is its asymmetric aspect. Steering can work in one direction but fail in the opposite direction. This type of one-way steering, which is different from the symmetry concepts of entanglement and Bell nonlocality, has garnered much interest. However, an experimental demonstration of genuine one-way EPR steering in the simplest scenario, i.e., one that employs two-qubit systems, is still lacking. In this Letter, we experimentally demonstrate one-way EPR steering with multimeasurement settings for a class of two-qubit states, which are still one-way steerable even with infinite settings. The steerability is quantified by the steering radius, which represents a necessary and sufficient steering criterion. The demonstrated one-way steering in the simplest bipartite quantum system is of fundamental interest and may provide potential applications in one-way quantum information tasks.

  13. Study on a New Steering Mechanism for Point-the-Bit Rotary Steerable System

    Directory of Open Access Journals (Sweden)

    Yuanzhi Li

    2014-02-01

    Full Text Available This paper presents a novel steering mechanism embedded in a point-the-bit rotary steerable system (RSS for oilfield exploitation. The new steering mechanism adopts a set of universal joints to alleviate the high alternative strain on drilling mandrel and employs a specially designed planetary gear small tooth number difference (PGSTD to achieve directional steering. Its principle and characteristics are explained and examined through a series of analyses. First, the eccentric displacement vector of the offset point on the drilling mandrel is formulated and kinematic solutions are established. Next, structural design for the new steering mechanism is addressed. Then, procedures and program architectures for simulating offset state of the drilling mandrel and motion trajectory of the whole steering mechanism are presented. After that, steering motion simulations of the new steering mechanism for both 2D and 3D well trajectories are then performed by combining LabVIEW and SolidWorks. Finally, experiments on the steering motion control of the new steering mechanism prototype are carried out. The simulations and experiments reveal that the steering performance of the new steering mechanism is satisfied. The research can provide good guidance for further research and engineering application of the point-the-bit RSS.

  14. Grazing behavior and production characteristics among cows differing in residual feed intake while grazing late season Idaho rangeland

    Science.gov (United States)

    The objectives were to determine if cows classified as either low- or high-residual feed intake (LRFI or HRFI) differed in BW, BCS, and winter grazing activity over time. Thirty Hereford x Angus (LRFI = 16; HRFI = 14) 2-year-old cows grazed sagebrush-steppe for 78 d beginning 29 September 2016. Body...

  15. Collision-model approach to steering of an open driven qubit

    Science.gov (United States)

    Beyer, Konstantin; Luoma, Kimmo; Strunz, Walter T.

    2018-03-01

    We investigate quantum steering of an open quantum system by measurements on its environment in the framework of collision models. As an example we consider a coherently driven qubit dissipatively coupled to a bath. We construct local nonadaptive and adaptive as well as nonlocal measurement scenarios specifying explicitly the measured observable on the environment. Our approach shows transparently how the conditional evolution of the open system depends on the type of the measurement scenario and the measured observables. These can then be optimized for steering. The nonlocal measurement scenario leads to maximal violation of the used steering inequality at zero temperature. Further, we investigate the robustness of the constructed scenarios against thermal noise. We find generally that steering becomes harder at higher temperatures. Surprisingly, the system can be steered even when bipartite entanglement between the system and individual subenvironments vanishes.

  16. 75 FR 29572 - Information Collection; Grazing Management

    Science.gov (United States)

    2010-05-26

    ... Control Number 1004-0019] Information Collection; Grazing Management AGENCY: Bureau of Land Management... submitted an information collection request to the Office of Management and Budget (OMB) for a 3-year... INFORMATION: Title: Grazing Management (43 CFR 4120). OMB Number: 1004-0019. Forms: 4120-6 (Cooperative Range...

  17. Revisiting path steering for 3D manipulation tasks

    NARCIS (Netherlands)

    L. Liu (Lei); J.-B. Martens; R. van Liere (Robert)

    2011-01-01

    htmlabstractThe law of path steering, as proposed by Accot and Zhai, describes a quantitative relationship between human temporal performance and the path spatial characteristics. The steering law is formulated as a continuous goal crossing task, in which a large number of goals are crossed along

  18. Revisiting path steering for 3D manipulation tasks

    NARCIS (Netherlands)

    L. Liu (Lei); J.-B. Martens; R. van Liere (Robert)

    2010-01-01

    htmlabstractThe law of path steering, as proposed by Accot and Zhai, describes a quantitative relationship between human temporal performance and the path spatial characteristics. The steering law is formulated as a continuous goal crossing task, in which a large number of goals are crossed along

  19. Bivalve grazing can shape phytoplankton communities

    Science.gov (United States)

    Lucas, Lisa; Cloern, James E.; Thompson, Janet K.; Stacey, Mark T.; Koseff, Jeffrey K.

    2016-01-01

    The ability of bivalve filter feeders to limit phytoplankton biomass in shallow waters is well-documented, but the role of bivalves in shaping phytoplankton communities is not. The coupled effect of bivalve grazing at the sediment-water interface and sinking of phytoplankton cells to that bottom filtration zone could influence the relative biomass of sinking (diatoms) and non-sinking phytoplankton. Simulations with a pseudo-2D numerical model showed that benthic filter feeding can interact with sinking to alter diatom:non-diatom ratios. Cases with the smallest proportion of diatom biomass were those with the fastest sinking speeds and strongest bivalve grazing rates. Hydrodynamics modulated the coupled sinking-grazing influence on phytoplankton communities. For example, in simulations with persistent stratification, the non-sinking forms accumulated in the surface layer away from bottom grazers while the sinking forms dropped out of the surface layer toward bottom grazers. Tidal-scale stratification also influenced vertical gradients of the two groups in opposite ways. The model was applied to Suisun Bay, a low-salinity habitat of the San Francisco Bay system that was transformed by the introduction of the exotic clam Potamocorbula amurensis. Simulation results for this Bay were similar to (but more muted than) those for generic habitats, indicating that P. amurensis grazing could have caused a disproportionate loss of diatoms after its introduction. Our model simulations suggest bivalve grazing affects both phytoplankton biomass and community composition in shallow waters. We view these results as hypotheses to be tested with experiments and more complex modeling approaches.

  20. White clover regenerative ability under N fertilizing and grazing

    Directory of Open Access Journals (Sweden)

    Josip Leto

    2008-12-01

    Full Text Available Recently, ecological and economic factors in milk and meat production stimulate use of legumes and grass-legumes mixtures, with zero or minimum mineral N as alternative to grass monoculture with high rate of mineral N. Research objective was to examine the effect of N application (0-N0 and 150 kg ha-1 year-1-N150 and rotational grazing by cattle (C and sheep (S on white clover: growing points number, stolon lenght, stolon dry weight, dry matter yield and clover contribution to total annual herbage production. N150 significantly reduced the growing points number, stolon length and stolon dry weight for more than 70 % compared to N0. Grazing treatment affected stolon population density only in interaction with N application because of N150 significantly reduced white clover population density only in sheep grazing. S-treatment had higher clover DM yield (0.21 t ha-1 than C-treatment (0.13 t ha-1. N0 had higher clover DM yield (0.25 t ha-1 than N150 (0.09 t ha-1. However, the interaction grazing management x N rate was significant for clover DM yield and clover contribution to total DM yield. N150 reduced both parameters for 80 % only in sheep grazing while difference in DM yield and clover contribution to total DM yield between grazing treatment was recorded only in N0 Sheep grazing increased DM yield for 150 % and clover contribution for 99 % compared to cattle grazing.

  1. Autonomous Shepherding Behaviors of Multiple Target Steering Robots.

    Science.gov (United States)

    Lee, Wonki; Kim, DaeEun

    2017-11-25

    This paper presents a distributed coordination methodology for multi-robot systems, based on nearest-neighbor interactions. Among many interesting tasks that may be performed using swarm robots, we propose a biologically-inspired control law for a shepherding task, whereby a group of external agents drives another group of agents to a desired location. First, we generated sheep-like robots that act like a flock. We assume that each agent is capable of measuring the relative location and velocity to each of its neighbors within a limited sensing area. Then, we designed a control strategy for shepherd-like robots that have information regarding where to go and a steering ability to control the flock, according to the robots' position relative to the flock. We define several independent behavior rules; each agent calculates to what extent it will move by summarizing each rule. The flocking sheep agents detect the steering agents and try to avoid them; this tendency leads to movement of the flock. Each steering agent only needs to focus on guiding the nearest flocking agent to the desired location. Without centralized coordination, multiple steering agents produce an arc formation to control the flock effectively. In addition, we propose a new rule for collecting behavior, whereby a scattered flock or multiple flocks are consolidated. From simulation results with multiple robots, we show that each robot performs actions for the shepherding behavior, and only a few steering agents are needed to control the whole flock. The results are displayed in maps that trace the paths of the flock and steering robots. Performance is evaluated via time cost and path accuracy to demonstrate the effectiveness of this approach.

  2. Autonomous Shepherding Behaviors of Multiple Target Steering Robots

    Directory of Open Access Journals (Sweden)

    Wonki Lee

    2017-11-01

    Full Text Available This paper presents a distributed coordination methodology for multi-robot systems, based on nearest-neighbor interactions. Among many interesting tasks that may be performed using swarm robots, we propose a biologically-inspired control law for a shepherding task, whereby a group of external agents drives another group of agents to a desired location. First, we generated sheep-like robots that act like a flock. We assume that each agent is capable of measuring the relative location and velocity to each of its neighbors within a limited sensing area. Then, we designed a control strategy for shepherd-like robots that have information regarding where to go and a steering ability to control the flock, according to the robots’ position relative to the flock. We define several independent behavior rules; each agent calculates to what extent it will move by summarizing each rule. The flocking sheep agents detect the steering agents and try to avoid them; this tendency leads to movement of the flock. Each steering agent only needs to focus on guiding the nearest flocking agent to the desired location. Without centralized coordination, multiple steering agents produce an arc formation to control the flock effectively. In addition, we propose a new rule for collecting behavior, whereby a scattered flock or multiple flocks are consolidated. From simulation results with multiple robots, we show that each robot performs actions for the shepherding behavior, and only a few steering agents are needed to control the whole flock. The results are displayed in maps that trace the paths of the flock and steering robots. Performance is evaluated via time cost and path accuracy to demonstrate the effectiveness of this approach.

  3. Drowsy Driver Detection via Steering Wheel

    Directory of Open Access Journals (Sweden)

    Herlina ABDUL RAHIM

    2010-09-01

    Full Text Available The main purpose of this project is to produce a safety system especially for fatigue car driver so as to prevent from accidents. The statistic on road fatality shows that human error constitute of 64.84 % road accidents fatality and 17.4 % due to technical factors. These systems encompassed the approach of hand pressure applied on the steering wheel. The steering will be installed with pressure sensors. At the same time these sensors can be used to measure gripping force while driving.

  4. Experimental EPR-steering using Bell-local states

    Science.gov (United States)

    Saunders, D. J.; Jones, S. J.; Wiseman, H. M.; Pryde, G. J.

    2010-11-01

    The concept of `steering' was introduced in 1935 by Schrödinger as a generalization of the EPR (Einstein-Podolsky-Rosen) paradox. It has recently been formalized as a quantum-information task with arbitrary bipartite states and measurements, for which the existence of entanglement is necessary but not sufficient. Previous experiments in this area have been restricted to an approach that followed the original EPR argument in considering only two different measurement settings per side. Here we demonstrate experimentally that EPR-steering occurs for mixed entangled states that are Bell local (that is, that cannot possibly demonstrate Bell non-locality). Unlike the case of Bell inequalities, increasing the number of measurement settings beyond two-we use up to six-significantly increases the robustness of the EPR-steering phenomenon to noise.

  5. Mixed grazing systems benefit both upland biodiversity and livestock production.

    Directory of Open Access Journals (Sweden)

    Mariecia D Fraser

    Full Text Available With world food demand expected to double by 2050, identifying farming systems that benefit both agricultural production and biodiversity is a fundamentally important challenge for the 21(st century, but this has to be achieved in a sustainable way. Livestock grazing management directly influences both economic outputs and biodiversity on upland farms while contributing to potentially damaging greenhouse gas emissions, yet no study has attempted to address these impacts simultaneously.Using a replicated, landscape-scale field experiment consisting of five management 'systems' we tested the effects of progressively altering elements within an upland farming system, viz i incorporating cattle grazing into an upland sheep system, ii integrating grazing of semi-natural rough grazing into a mixed grazing system based on improved pasture, iii altering the stocking ratio within a mixed grazing system, and iv replacing modern crossbred cattle with a traditional breed. We quantified the impacts on livestock productivity and numbers of birds and butterflies over four years.We found that management systems incorporating mixed grazing with cattle improve livestock productivity and reduce methane emissions relative to sheep only systems. Systems that also included semi-natural rough grazing consistently supported more species of birds and butterflies, and it was possible to incorporate bouts of summer grazing of these pastures by cattle to meet habitat management prescriptions without compromising cattle performance overall. We found no evidence that the system incorporating a cattle breed popular as a conservation grazer was any better for bird and butterfly species richness than those based on a mainstream breed, yet methane emissions from such a system were predicted to be higher. We have demonstrated that mixed upland grazing systems not only improve livestock production, but also benefit biodiversity, suggesting a 'win-win' solution for farmers and

  6. High motility reduces grazing mortality of planktonic bacteria

    DEFF Research Database (Denmark)

    Matz, Carsten; Jurgens, K.

    2005-01-01

    We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated...... size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 mum(3). Grazing mortality was lowest for cells of >0.5 mum(3) and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (less than or equal to0.1 mum......(3), >50 mum s(-1)) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing....

  7. Chaos vibration of pinion and rack steering trapezoidal mechanism containing two clearances

    Science.gov (United States)

    Wei, Daogao; Wang, Yu; Jiang, Tong; Zheng, Sifa; Zhao, Wenjing; Pan, Zhijie

    2017-08-01

    The multi-clearances of breaking type steering trapezoidal mechanism joints influences vehicle steering stability. Hence, to ascertain the influence of clearance value on steering stability, this paper takes the steering mechanism of a certain vehicle type as a prototype that can be simplified into a planar six-bar linkage, then establishes the system dynamic differential equations after considering the two clearances of tie rods and the steering knuckle arms. The influence of the clearance parameters on the movement stability of the steering mechanism is studied using a numerical computation method. Results show that when the two clearances are equal, the planar movement of the tie rods changes from period-doubling to chaos as the clearances increase. When the two clearances are 0.25 mm and 1.5 mm respectively, the planar movements of the two side tie rods come into chaos, causing the steering stability to deteriorate. Moreover, with the increase of clearances, turning moment fluctuates more intensively and the peak value increases.

  8. Operational experience with model-based steering in the SLC linac

    International Nuclear Information System (INIS)

    Thompson, K.A.; Himel, T.; Moore, S.; Sanchez-Chopitea, L.; Shoaee, H.

    1989-03-01

    Operational experience with model-driven steering in the linac of the Stanford Linear Collider is discussed. Important issues include two-beam steering, sensitivity of algorithms to faulty components, sources of disagreement with the model, and the effects of the finite resolution of beam position monitors. Methods developed to make the steering algorithms more robust in the presence of such complications are also presented. 5 refs., 1 fig

  9. The Optimal Steering Control System using Imperialist Competitive Algorithm on Vehicles with Steer-by-Wire System

    Directory of Open Access Journals (Sweden)

    F. Hunaini

    2015-03-01

    Full Text Available Steer-by-wire is the electrical steering systems on vehicles that are expected with the development of an optimal control system can improve the dynamic performance of the vehicle. This paper aims to optimize the control systems, namely Fuzzy Logic Control (FLC and the Proportional, Integral and Derivative (PID control on the vehicle steering system using Imperialist Competitive Algorithm (ICA. The control systems are built in a cascade, FLC to suppress errors in the lateral motion and the PID control to minimize the error in the yaw motion of the vehicle. FLC is built has two inputs (error and delta error and single output. Each input and output consists of three Membership Function (MF in the form of a triangular for language term "zero" and two trapezoidal for language term "negative" and "positive". In order to work optimally, each MF optimized using ICA to get the position and width of the most appropriate. Likewise, in the PID control, the constant at each Proportional, Integral and Derivative control also optimized using ICA, so there are six parameters of the control system are simultaneously optimized by ICA. Simulations performed on vehicle models with 10 Degree Of Freedom (DOF, the plant input using the variables of steering that expressed in the desired trajectory, and the plant outputs are lateral and yaw motion. The simulation results showed that the FLC-PID control system optimized by using ICA can maintain the movement of vehicle according to the desired trajectory with lower error and higher speed limits than optimized with Particle Swarm Optimization (PSO.

  10. Self-testing through EPR-steering

    International Nuclear Information System (INIS)

    Šupić, Ivan; Hoban, Matty J

    2016-01-01

    The verification of quantum devices is an important aspect of quantum information, especially with the emergence of more advanced experimental implementations of quantum computation and secure communication. Within this, the theory of device-independent robust self-testing via Bell tests has reached a level of maturity now that many quantum states and measurements can be verified without direct access to the quantum systems: interaction with the devices is solely classical. However, the requirements for this robust level of verification are daunting and require high levels of experimental accuracy. In this paper we discuss the possibility of self-testing where we only have direct access to one part of the quantum device. This motivates the study of self-testing via EPR-steering, an intermediate form of entanglement verification between full state tomography and Bell tests. Quantum non-locality implies EPR-steering so results in the former can apply in the latter, but we ask what advantages may be gleaned from the latter over the former given that one can do partial state tomography? We show that in the case of self-testing a maximally entangled two-qubit state, or ebit, EPR-steering allows for simpler analysis and better error tolerance than in the case of full device-independence. On the other hand, this improvement is only a constant improvement and (up to constants) is the best one can hope for. Finally, we indicate that the main advantage in self-testing based on EPR-steering could be in the case of self-testing multi-partite quantum states and measurements. For example, it may be easier to establish a tensor product structure for a particular party’s Hilbert space even if we do not have access to their part of the global quantum system. (paper)

  11. Longer rest periods for intensive rotational grazing limit diet quality ...

    African Journals Online (AJOL)

    Longer rest periods for intensive rotational grazing limit diet quality of sheep without enhancing environmental benefits. ... This experiment was established to compare three intensive rotational grazing strategies (fast rotation [FR], average 57-day rest; slow rotation [SR], average 114-day rest; and flexible grazing [FX], based ...

  12. Effects of anthelmintic treatment and feed supplementation on grazing Tuli weaner steers naturally infected with gastrointestinal nematodes

    Directory of Open Access Journals (Sweden)

    A. Magaya

    2000-07-01

    Full Text Available A study was carried out to determine the epidemiology of gastrointestinal nematodes in indigenous Tuli cattle and the effect of dietary protein supplementation and anthelmintic treatment on productivity in young growing cattle. Forty steers with an average age of 18 months were divided into 4 groups; 1 fenbendazole (slow release bolus and cottonseed meal (FCSM group, 2 fenbendazole (FBZ group, 3 cottonseed meal (CSM group and 4 control (no cottonseed meal and no fenbendazole (control group. Performance parameters measured included wormeggs per gram of faeces (EPG, packed cell volume (PCV, albumin and live-weight gain. Results showed that faecal worm egg counts were lower and PCV was higher in the FCSM and FBZ groups than in the CSM and control groups (P < 0.01. Weight gains were higher in the CSMand FCSM groups than in the FBZ and control groups (P < 0.05. The cost benefits of anthelmintic treatment and dietary supplementation were apparent in this study. The improved growth performance of the FCSM, FBZ and CSM groups reflected a financial gain over the controls on termination of the study. The dominant genera of gastrointestinal nematodes on faecal culture, pasture larval counts and necropsy were Cooperia and Haemonchus. The incidences of Trichostrongylus, Oesophagostomum and Bunostomum were low.

  13. Research on Sliding Mode Control for Steer-by-Wire System in Forklift

    Directory of Open Access Journals (Sweden)

    Huang Jun-Jie

    2017-01-01

    Full Text Available Aiming at steering stability and wheel angle tracking of steer-by-wire (SBW three wheeled forklift, steering dynamic model and SBW system mathematical model of three wheeled forklift are established. A control strategy for the ideal transmission ratio is introduced based on this model, which ensures forklift steering gain invariant. A sliding mode controller can then be designed based on the bound information of uncertain system parameters, uncertain self-aligning torque, and external disturbances. The results of simulation show the control strategies above can effectively reduce the sideslip angle when the forklift is steering and improve the sensitivity and stability of the steering forklift; at the same time can effectively restrain the parameter perturbation of internal system and external disturbance, which improves the tracking performance of the wheel angle.

  14. Strong Einstein-Podolsky-Rosen steering with unconditional entangled states

    Science.gov (United States)

    Steinlechner, Sebastian; Bauchrowitz, Jöran; Eberle, Tobias; Schnabel, Roman

    2013-02-01

    In 1935 Schrödinger introduced the terms entanglement and steering in the context of the famous gedanken experiment discussed by Einstein, Podolsky, and Rosen (EPR). Here, we report on a sixfold increase of the observed EPR-steering effect with regard to previous experiments, as quantified by the Reid criterion. We achieved an unprecedented low conditional variance product of about 0.04<1, where 1 is the upper bound below which steering is demonstrated. The steering effect was observed on an unconditional two-mode-squeezed entangled state that contained a total vacuum state contribution of less than 8%, including detection imperfections. Together with the achieved high interference contrast between the entangled state and a bright coherent laser field, our state is compatible with efficient applications in high-power laser interferometers and fiber-based networks for entanglement distribution.

  15. The transmission of Fasciola spp. to cattle and contamination of grazing areas with Fasciola eggs in the Red River Delta region of Vietnam.

    Science.gov (United States)

    Lan Anh, Nguyen Thi; Thanh, Dao Thi Ha; Hoan, Doan Huu; Thuy, Do Thu; Khong, Nguyen Viet; Anderson, Norman

    2014-04-01

    At four times during November 2010, cattle with infections of Fasciola spp., in two communes of northern Vietnam, were allocated to two equivalent groups. Cattle in one group were treated with triclabendazole. Faecal samples collected monthly from both groups were tested for Fasciola copro-antigens and the presence of Fasciola eggs. Re-infection of treated cattle occurred from early March to late November, coinciding with high weekly totals of rainfall. Contamination of grazing areas by untreated cattle was high and relatively constant throughout the year. However, contamination was reduced to undetectable amounts for 8 to 12 weeks after treatment and even at 20 weeks was only 50% or less of the pre-treatment amounts. Therefore, treatments given in mid-September and again in early April, at the start of the wet season, may be sufficient to prevent contamination of grazing areas and reduce the prevalence and severity of Fasciola infections in cattle.

  16. Zooplankton grazing in a eutrophic lake: implications of diel vertical migration

    International Nuclear Information System (INIS)

    Lampert, W.; Taylor, B.E.

    1985-01-01

    During summer and fall, depth profiles of zooplankton community grazing were determined in situ during day and night in the Schoehsee, a small eutrophic lake. Labeled algae of two different sizes were mixed with the natural suspension of phytoplankton in a grazing chamber. A small blue-green alga (Synechococcus, 1 μm) was labeled with 32 P; a larger green alga (Scenedesmus, 4-15 μm) was labeled with 14 C. During summer, grazing in the upper 5 m was negligible during day but strong at night. Hence, algae grow relatively unimpeded by grazing during daytime but are harvested at night. Vertical and diel differences in grazing rates disappeared when the vertical migration ceased in fall. Selectivity of grazing was controlled by the zooplankton species composition. Eudiaptomus showed a strong preference for Scenedesmus. Daphnia showed a slight preference for Scenedesmus, but Ceriodaphnia preferred Synechococcus. Cyclopoid copepodites did not ingest the small blue-green. Because Daphnia and Eudiaptomus were dominant, grazing rates on larger cells were usually higher than grazing rates on the small cells. Negative electivity indices for scenedesmus occurred only when the biomass of large crustaceans was extremely low (near the surface, during day). Zooplankton biomass was the main factor controlling both vertical and seasonal variations in grazing. Highest grazing rates (65%/d) were measured during fall when zooplankton abundance was high. Because differential losses can produce substantial errors in the results, it was necessary to process the samples on the boat immediately after collection, without preservation

  17. Bison grazing increases arthropod abundance and diversity in a tallgrass prairie.

    Science.gov (United States)

    Moran, Matthew D

    2014-10-01

    How grazing-induced ecosystem changes by ungulates indirectly affect other consumers is a question of great interest. I investigated the effect of grazing by American Bison (Bos bison L.) on an arthropod community in tallgrass prairie. Grazing increased the abundance of arthropods, an increase that was present in both herbivorous and carnivorous assemblages, but not in detritivores. The increase in herbivores and reduction in plant biomass from grazing resulted in an arthropod herbivore load almost three times higher in grazed plots compared with controls. Among herbivores, the sap-feeding insect guild was dramatically more abundant, while chewing herbivores were not affected. Herbivorous and carnivorous arthropod richness was higher in grazed plots, although the response was strongest among herbivores. Arthropod abundance on individual grasses and forbs was significantly higher in grazed areas, while plant type had no effect on abundance, indicating that the change was ecosystem-wide and not simply in response to a reduction in grass biomass from grazing. The response of arthropods to grazing was strongest in the early part of the growing season. Published research shows that ungulate grazing, although decreasing available biomass to other consumers, enhances plant quality by increasing nitrogen level in plants. The arthropod results of this study suggest higher plant quality outweighs the potential negative competitive effects of plant biomass removal, although other activities of bison could not be ruled out as the causative mechanism. Because arthropods are extremely abundant organisms in grasslands and a food source for other consumers, bison may represent valuable management tools for maintaining biodiversity.

  18. Introducing cattle grazing to a noxious weed-dominated rangeland shifts plant communities

    Directory of Open Access Journals (Sweden)

    Josh S. Davy

    2015-10-01

    Full Text Available Invasive weed species in California's rangelands can reduce herbaceous diversity, forage quality and wildlife habitat. Small-scale studies (5 acres or fewer have shown reductions of medusahead and yellow starthistle using prescribed grazing on rangelands, but little is published on the effects of pasture-scale (greater than 80 acres prescribed grazing on weed control and plant community responses. We report the results of a 6-year collaborative study of manager-applied prescribed grazing implemented on rangeland that had not been grazed for 4 years. Grazing reduced medusahead but did not alter yellow starthistle cover. Medusahead reductions were only seen in years that did not have significant late spring rainfall, suggesting that it is able to recover from heavy grazing if soil moisture is present. Later season grazing appears to have the potential to suppress medusahead in all years. In practice, however, such grazing is constrained by livestock drinking water availability and forage quality, which were limited even in years with late spring rainfall. Thus, we expect that grazing treatments under real-world constraints would reduce medusahead only in years with little late spring rainfall. After 10 years of grazing exclusion, the ungrazed plant communities began to shift, replacing medusahead with species that have little value, such as ripgut and red brome.

  19. 36 CFR 251.103 - Mediation of term grazing permit disputes.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Mediation of term grazing... Lands § 251.103 Mediation of term grazing permit disputes. (a) Decisions subject to mediation. In those States with Department of Agriculture certified mediation programs, any holder of a term grazing permit...

  20. Desempenho de novilhos suplementados com sais proteinados em pastagem nativa Performance of steers supplemented with protein salts on native pastures

    Directory of Open Access Journals (Sweden)

    Marcelo Knorr

    2005-08-01

    Full Text Available O objetivo deste trabalho foi avaliar o efeito da suplementação com sais proteinados sobre o desempenho de novilhos em pastagem nativa diferida, no Rio Grande do Sul, Brasil. Os suplementos de sal proteinado avaliados foram: com uréia, com amiréia, com amiréia mais levedura e sal mineral. O experimento teve duração de 118 dias e foram utilizadas 8 parcelas com área de 7,5 ha, cada uma com 8 novilhos, de peso médio 264 kg, com idade de 18 meses, em delineamento completamente casualizado. A pastagem apresentou valores médios de 6,8% de proteína bruta, 73,3% de fibra em detergente neutro, e 42,5% de digestibilidade in vitro da matéria orgânica, sem que fossem detectadas diferenças significativas entre tratamentos. O ganho médio diário (0,287 kg dos animais suplementados com o sal proteinado com amiréia e levedura, foi superior ao apresentado pelos animais que consumiram sal mineralizado (0,019 kg mas não houve diferenças entre uréia (0,159 kg e amiréia (0,124 kg. O consumo diário dos suplementos proteinados (0,400 kg foi superior ao consumo do suplemento mineral (0,038 kg. A adição de levedura ativa, ao sal proteinado formulado com amiréia, melhora o desempenho de novilhos em pastagem nativa diferida.The objective of this work was to evaluate the effect of protein salts supplementation on performance of beef steers grazing differed native pasture in Rio Grande do Sul State, Brazil. Protein salts were supplemented with: urea, starea, starea plus yeast, and mineral salt. The experiment was conducted during 118 days, and utilized 8 paddocks with 7.5 ha each one, with 8 steers averaging 264 kg and 18 months old, in a completely randomized design. Average composition of pasture was 6.8% of crude protein, 73.3% of neutral detergent fiber, and 42.5% in vitro organic matter digestibility; significative differences weren't detected among treatments. Average daily weight gain of animals fed protein salt with starea plus yeast (0

  1. Grazing-incident PIXE Analysis Technology

    International Nuclear Information System (INIS)

    Li Hongri; Wang Guangpu; Liang Kun; Yang Ru; Han Dejun

    2009-01-01

    In the article, the grazing incidence technology is first applied to the PIXE (proton induced X-ray emission) analysis. Three pieces of samples were investigated, including the contaminated aluminium substrate, the SIMOX (separated by oxygen implantation) SOI (Silicon on Insulator) sample and the silicon wafer implanted with Fe + . The results reveal that the grazing-incident proton can improve the sensitivity of PIXE in trace analysis, especially for samples contaminated on surface. With the penetration depth of the proton bean decreased, the ratio of the peak area to the detection limit raised observably and the sensitivity near the sample surface increased. (authors)

  2. Effect of By-product Feed-based Silage Feeding on the Performance, Blood Metabolites, and Carcass Characteristics of Hanwoo Steers (a Field Study).

    Science.gov (United States)

    Kim, Y I; Park, J M; Lee, Y H; Lee, M; Choi, D Y; Kwak, W S

    2015-02-01

    This study was conducted to determine the effects of feeding by-product feed (BF)-based silage on the performance, blood metabolite parameters, and carcass characteristics of Hanwoo steers. The BF-based silage was composed of 50% spent mushroom substrate, 21% recycled poultry bedding, 15% cut ryegrass straw, 10.8% rice bran, 2% molasses, 0.6% bentonite, and 0.6% microbial additive (on a wet basis), and ensiled for over 5 d. Fifteen steers were allocated to three diets during the growing and fattening periods (3.1 and 9.8 months, respectively): a control diet (concentrate mix and free access to rice straw), a 50% BF-based silage diet (control diet+50% of maximum BF-based silage intake), and a 100% BF-based silage diet (the same amount of concentrate mix and ad libitum BF-based silage). The BF-based silage was fed during the growing and fattening periods, and was replaced with larger particles of rice straw during the finishing period. After 19.6 months of the whole period all the steers were slaughtered. Compared with feeding rice straw, feeding BF-based silage tended (p = 0.10) to increase the average daily gain (27%) and feed efficiency (18%) of the growing steers, caused by increased voluntary feed intake. Feeding BF-based silage had little effect on serum constituents, electrolytes, enzymes, or the blood cell profiles of fattening steers, except for low serum Ca and high blood urea concentrations (p<0.05). Feeding BF-based silage did not affect cold carcass weight, yield traits such as back fat thickness, longissimus muscle area, yield index or yield grade, or quality traits such as meat color, fat color, texture, maturity, marbling score, or quality grade. However, it improved good quality grade (1(+) and 1(++)) appearance rates (60% for the control group vs 100% for the BF-based silage-fed groups). In conclusion, cheap BF-based silage could be successfully used as a good quality roughage source for beef cattle.

  3. Microbial Protein Production and Nitrogen Balance of Local Steer Fed Ammoniated Rice Straws Added

    Directory of Open Access Journals (Sweden)

    H Hindratiningrum

    2009-05-01

    Full Text Available The objective of the experiment was to investigate the kind of energy source feedstuffs on nutrient balance and microbial protein synthesis in local male beef cattle fed with ammoniated rice straws Twenty steers Peranakan Ongole (PO with average age 1-2 years old were used. They were divided 5 groups based on initial body weight as block. Therefore, Completely Randomised Block Design (CBRD was used for this experiment. Data were analysed by analysis variance and continued honestly significant different (HSD to test the differences between means. The result showed that the range MCP and eficiency MCP were 154,61 g/d until 226,54 g/d and 54,08 gMCP/kg DOMR until 62,64 gMCP/kg DOMR. The range of nitrogen balance were 72,28 gram until 111,67 gram. MCP and efficiency MCP were not affected (P>0,05 by the treatments but balance of nitrogen was affected (P<0,05. Diet containing fresh cassava waste as energy source (R2 was lower (P<0,05 than R1 and R4 while between R1,R3 and R4 was similar. This results indicate that feed source of energy (rice brand, wet cassava waste, dry cassava waste and corn can be used in steers with rice straw ensilage as forage. (Animal Production 11(2: 116-121 (2009 Key Words : Microbial protein production, nitrogen balance, rice straw, ensilage

  4. The impact of force feedback level on steering performance

    NARCIS (Netherlands)

    Anand, S.; Terken, J.; Hogema, J.H.

    2013-01-01

    Steer-by-wire systems provide designers the ability to customize and personalize force feedback on the steering wheel, based on individual preferences. Earlier studies using subjective responses have shown that there are individual differences in preferences for force feedback. It has also been

  5. Horse grazing systems: understory biomass and plant biodiversity of a Pinus radiata stand

    Directory of Open Access Journals (Sweden)

    Antonio Rigueiro-Rodríguez

    2012-02-01

    Full Text Available Horse grazing systems may affect productivity and biodiversity of understory developed under Pinus radiata D. Don silvopastoral systems, while acting as a tool to reduce the risk of fire. This study compared continuous and rotational grazing systems effect upon biomass, fractions of stem, sprouts, leaves and woody parts of Ulex europaeus L. and alpha (Species Richness, Shannon-Wiener and beta (Jaccard and Magurran biodiversity for a period of four years in a P. radiata silvopastoral system. The experiment consisted of a randomized block design of two treatments (continuous and rotational grazing. Biomass, and species abundances were measured - biodiversity metrics were calculated based on these results for a two years of grazing and two years of post-grazing periods. Both continuous and rotational grazing systems were useful tools for reducing biomass and, therefore, fire risk. The rotational grazing system caused damage to the U. europaeus shrub, limiting its recovery once grazing was stopped. However, the more intensive grazing of U. europaeus plants under rotational had a positive effect on both alpha and beta biodiversity indexes due to the low capacity of food selection in the whole plot rather than continuous grazing systems. Biomass was not affected by the grazing system; however the rotational grazing system is more appropriate to reduce U. europaeus biomass and therefore forest fire risk at a long term and to enhance pasture biodiversity than the continuous grazing system.

  6. Grass species selection patterns on rotationally-grazed Dohne ...

    African Journals Online (AJOL)

    Herbaceous species preference was studied during autumn and winter periods of occupation, on rotationally-grazed Dohne Sourveld, at four different stocking rates. Reports on species selection by cattle and sheep grazing together. Illustrates with graphsLanguage: English. Keywords: Grass species; Herbage availibility; ...

  7. EVALUATION OF A CONCEPTUAL VEHICLE STEERING SYSTEM FOR INDEPENDENT WHEEL CONTROL

    Directory of Open Access Journals (Sweden)

    Ryszard BUCHALIK

    2017-03-01

    Full Text Available This paper presents a brief description of an unconventional steering system involving electronic stability control and its influence on vehicle motion. The proposed configuration enables individual changes in steering angle for each single wheel, in contrast to the mechanical linkage solution. An analysis of vehicle behaviour during emergency braking on a heterogeneous surface is conducted, especially with regard to the undesirable rotation of the vehicle body. The benefits of using this active steering system, implemented in the steer-by-wire mode, are characterized, while the problems for further consideration and the potential benefits of such a solution are described.

  8. Effects of past and present livestock grazing on herpetofauna in a landscape-scale experiment.

    Science.gov (United States)

    Kay, Geoffrey M; Mortelliti, Alessio; Tulloch, Ayesha; Barton, Philip; Florance, Daniel; Cunningham, Saul A; Lindenmayer, David B

    2017-04-01

    Livestock grazing is the most widespread land use on Earth and can have negative effects on biodiversity. Yet, many of the mechanisms by which grazing leads to changes in biodiversity remain unresolved. One reason is that conventional grazing studies often target broad treatments rather than specific parameters of grazing (e.g., intensity, duration, and frequency) or fail to account for historical grazing effects. We conducted a landscape-scale replicated grazing experiment (15,000 km 2 , 97 sites) to examine the impact of past grazing management and current grazing regimes (intensity, duration, and frequency) on a community of ground-dwelling herpetofauna (39 species). We analyzed community variables (species richness and composition) for all species and built multiseason patch-occupancy models to predict local colonization and extinction for the 7 most abundant species. Past grazing practices did not influence community richness but did affect community composition and patch colonization and extinction for 4 of 7 species. Present grazing parameters did not influence community richness or composition, but 6 of the 7 target species were affected by at least one grazing parameter. Grazing frequency had the most consistent influence, positively affecting 3 of 7 species (increased colonization or decreased extinction). Past grazing practice affected community composition and population dynamics in some species in different ways, which suggests that conservation planners should examine the different grazing histories of an area. Species responded differently to specific current grazing practices; thus, incentive programs that apply a diversity of approaches rather than focusing on a change such as reduced grazing intensity should be considered. Based on our findings, we suggest that determining fine-scale grazing attributes is essential for advancing grazing as a conservation strategy. © 2016 Society for Conservation Biology.

  9. Robotic needle steering: design, modeling, planning, and image guidance

    NARCIS (Netherlands)

    Cowan, Noah J.; Goldberg, Ken; Chirikjian, Gregory S.; Fichtinger, Gabor; Alterovitz, Ron; Reed, Kyle B.; Kallem, Vinutha; Misra, Sarthak; Park, Wooram; Okamura, Allison M.; Rosen, Jacob; Hannaford, Blake; Satava, Richard M.

    2010-01-01

    This chapter describes how advances in needle design, modeling, planning, and image guidance make it possible to steer flexible needles from outside the body to reach specified anatomical targets not accessible using traditional needle insertion methods. Steering can be achieved using a variety of

  10. Multiquantum well beam-steering device for laser satellite communication

    Science.gov (United States)

    Lahat, Roee; Levy, Itamar; Shlomi, Arnon

    2002-01-01

    With the increasing interest in laser satellite communications, new methods are sought to solve the existing problems of accurate and rapid laser beam deflection. Current solutions in the form of galvanometers or piezo fast steering mirrors with one or two degrees of freedom are bulky, power-consuming and slow. The Multi-Quantum Well (MQW) is a semiconductor device with unique potential to steer laser beams without any moving parts. We have conducted a preliminary evaluation of the potential application of the MQW as a laser beam-steering device for laser satellite communication, examining the performance of critical parameters for this type of communications.

  11. Reducing Digging Losses by Using Automated Steering to Plant and Invert Peanuts

    Directory of Open Access Journals (Sweden)

    George Vellidis

    2014-07-01

    Full Text Available GPS guidance of farm machinery has been increasingly adopted by farmers because of the perceived gains in efficiency that it provides. In the southeastern USA one of the reasons farmers adopt GPS guidance, and specifically automated steering (auto-steer, is that it can theoretically result in large yield gains when used to plant and invert peanuts—one of the region’s most important crops. The goal of our study was to quantify the yield benefit of using real time kinematic (RTK-based auto-steer to plant and invert peanuts under a variety of terrain conditions. Yield benefits result from reduced digging losses. The study was conducted for two consecutive years (2010 and 2011 on a private farm in Georgia, USA. When all data are grouped together, auto-steer outperformed conventional by 579 kg/ha in 2010 and 451 kg/ha in 2011. We also evaluated the performance of auto-steer under different curvature conditions using low, medium, and high curvature rows. The results showed that auto-steer outperformed conventional under all curvature by a minimum of 338 kg/ha. Finally, we evaluated passive implement guidance in combination with auto-steer and found that it holds tremendous potential for further reducing digging losses. In many cases, auto-steer will pay for itself within a year.

  12. Forage patch use by grazing herbivores in a South African grazing ecosystem

    NARCIS (Netherlands)

    Venter, J.A.; Nabe-Nielsen, J.; Prins, H.H.T.; Slotow, R.

    2014-01-01

    Understanding how different herbivores make forage patch use choices explains how they maintain an adequate nutritional status, which is important for effective conservation management of grazing ecosystems. Using telemetry data, we investigated nonruminant zebra (Equus burchelli) and ruminant red

  13. Livestock grazing and the desert tortoise in the Mojave Desert

    Science.gov (United States)

    Oldemeyer, John L.

    1994-01-01

    A large part of the Mojave Desert is not in pristine condition, and some current conditions can be related to past grazing-management practices. No information could be found on densities of the desert tortoise (Gopherus agassizii) or on vegetative conditions of areas that had not been grazed to allow managers a comparison of range conditions with data on tortoises. Experimental information to assess the effect of livestock grazing on tortoises is lacking, and researchers have not yet examined whether the forage that remains after grazing is sufficient to meet the nutritional needs of desert tortoises.

  14. Review: Behavior and daily grazing patterns of cattle

    NARCIS (Netherlands)

    Gregorini, P.; Tamminga, S.; Gunther, S.A.

    2006-01-01

    Grazing ruminants consume their food in discrete grazing events. The frequency and distribution of these events depend on the current physiological state of the animal and its environment. Within a small spatio-temporal scale, foraging decisions such as when to begin, which frequency, and how to

  15. Modeling of Driver Steering Operations in Lateral Wind Disturbances toward Driver Assistance System

    Science.gov (United States)

    Kurata, Yoshinori; Wada, Takahiro; Kamiji, Norimasa; Doi, Shun'ichi

    Disturbances decrease vehicle stability and increase driver's mental and physical workload. Especially unexpected disturbances such as lateral winds have severe effect on vehicle stability and driver's workload. This study aims at building a driver model of steering operations in lateral wind toward developing effective driver assistance system. First, the relationship between the driver's lateral motion and its reactive quick steering behavior is investigated using driving simulator with lateral 1dof motion. In the experiments, four different wind patterns are displayed by the simulator. As the results, strong correlation was found between the driver's head lateral jerk by the lateral disturbance and the angular acceleration of the steering wheel. Then, we build a mathematical model of driver's steering model from lateral disturbance input to steering torque of the reactive quick feed-forward steering based on the experimental results. Finally, validity of the proposed model is shown by comparing the steering torque of experimental results and that of simulation results.

  16. Steering, Entanglement, Nonlocality, and the EPR Paradox

    OpenAIRE

    Wiseman, H. M.; Jones, S. J.; Doherty, A. C.

    2006-01-01

    The concept of steering was introduced by Schrodinger in 1935 as a generalization of the EPR paradox for arbitrary pure bipartite entangled states and arbitrary measurements by one party. Until now, it has never been rigorously defined, so it has not been known (for example) what mixed states are steerable (that is, can be used to exhibit steering). We provide an operational definition, from which we prove (by considering Werner states and Isotropic states) that steerable states are a strict ...

  17. Dynamics of forage accumulation in Elephant grass subjected to rotational grazing intensities

    Directory of Open Access Journals (Sweden)

    Braulio Maia de Lana Sousa

    2013-09-01

    Full Text Available We assessed the accumulation dynamics of forage and its components in Elephant grass cv. Napier (Pennisetum purpureum Schum. that were subjected to three post-grazing height treatments (30, 50, and 70 cm from February through May 2009 (experiment one and December 2009 through May 2010 (experiment two. In experiment one, the grazing events started when the light interception by the canopy reached 95%. The same was adopted for experiment two, except for the first grazing event, which was based on the height of the apical meristems of basal tillers. The experimental design for both experiments was a randomized complete block with three replications. The pastures that were managed at a post-grazing height of 30 cm exhibited lower rates of leaf and stem growth, total growth and forage accumulation than those that were managed at 50 or 70 cm, indicating that post-grazing height affects Elephant grass. The pastures that were managed at 50 cm exhibited relatively stable accumulation rates and less stem accumulation. Pastures managed at 70 cm of pos-grazing height presented more leaf and stem accumulation. Most apical meristems of Elephant grass should be removed in the first grazing when they reach the post-grazing target height of 50 cm. The elevation in the residual post-grazing height, especially in the summer, raises the regrowth vigor in the Elephant grass cv. Napier pasture. The post-grazing height of 30 cm reduces the growth of the Elephant grass cv. Napier.

  18. Grazing livestock are exposed to terrestrial cyanobacteria.

    Science.gov (United States)

    McGorum, Bruce C; Pirie, R Scott; Glendinning, Laura; McLachlan, Gerry; Metcalf, James S; Banack, Sandra A; Cox, Paul A; Codd, Geoffrey A

    2015-02-25

    While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the cyanobacterial neurotoxins β-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock.

  19. Grazing reduces soil greenhouse gas fluxes in global grasslands: a meta-analysis

    Science.gov (United States)

    Tang, Shiming; Tian, Dashuan; Niu, Shuli

    2017-04-01

    Grazing causes a worldwide degradation in grassland and likely alters soil greenhouse gas fluxes (GHGs). However, the general patterns of grazing-induced changes in grassland soil GHGs and the underlying mechanisms remain unclear. Thus, we synthesized 63 independent experiments in global grasslands that examined grazing impacts on soil GHGs (CO2, CH4 and N2O). We found that grazing with light or moderate intensity did not significantly influence soil GHGs, but consistently depressed them under heavy grazing, reducing CO2 emission by 10.55%, CH4 uptake by 19.24% and N2O emission by 28.04%. The reduction in soil CO2 was mainly due to decreased activity in roots and microbes (soil respiration per unit root and microbial biomass), which was suppressed by less water availability due to higher soil temperature induced by lower community cover under heavy grazing. N2O emission decreased with grazing-caused decline in soil total N. The inhibitory effect on methanotroph activities by water stress is responsible for the decreased CH4 uptake. Furthermore, grazing duration and precipitation also influenced the direction and magnitude of responses in GHGs fluxes. Overall, our results indicate that the reduction in soil CO2 and N2O emission under heavy grazing is partially compensated by the decrease in CH4 uptake, which is mainly regulated by variations in soil moisture.

  20. STEER Coastal Use Mapping Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Coastal Use Mapping Project is designed to collect critical information on human activities in and near the St. Thomas East End Reserves (STEER). The project...

  1. Design of a Path-Tracking Steering Controller for Autonomous Vehicles

    Directory of Open Access Journals (Sweden)

    Chuanyang Sun

    2018-06-01

    Full Text Available This paper presents a linearization method for the vehicle and tire models under the model predictive control (MPC scheme, and proposes a linear model-based MPC path-tracking steering controller for autonomous vehicles. The steering controller is designed to minimize lateral path-tracking deviation at high speeds. The vehicle model is linearized by a sequence of supposed steering angles, which are obtained by assuming the vehicle can reach the desired path at the end of the MPC prediction horizon and stay in a steady-state condition. The lateral force of the front tire is directly used as the control input of the model, and the rear tire’s lateral force is linearized by an equivalent cornering stiffness. The course-direction deviation, which is the angle between the velocity vector and the path heading, is chosen as a control reference state. The linearization model is validated through the simulation, and the results show high prediction accuracy even in regions of large steering angle. This steering controller is tested through simulations on the CarSim-Simulink platform (R2013b, MathWorks, Natick, MA, USA, showing the improved performance of the present controller at high speeds.

  2. Population Dynamics and Transcriptomic Responses of Chorthippus albonemus (Orthoptera: Acrididae to Herbivore Grazing Intensity

    Directory of Open Access Journals (Sweden)

    Xinghu Qin

    2017-11-01

    Full Text Available Livestock grazing can trigger outbreaks of insect pests in steppe ecosystems of Inner Mongolia in China. However, the physiological responses of the grasshopper Chorthippus albonemus to grazing are not well-understood. Here we investigated the effects of sheep grazing on the population dynamics and transcriptomic response of C. albonemus. We collected the insects three times (about 20 days apart in 1.33-ha plots in which there were no grazing, light grazing, moderate grazing, heavy grazing, or overgrazing. Our results showed that continuous grazing significantly decreased plant biomass and influenced plant succession. Total insect species diversity significantly declined along the grazing intensity gradient and over time. Results of the first two collections of C. albonemus indicated that moderate grazing significantly increased the abundance of C. albonemus. However, abundance was significantly decreased in plots that were overgrazed, possibly because of food stress and environmental pressures. Under moderate grazing, betA and CHDH genes were significantly upregulated in C. albonemus. In response to higher grazing intensity, upregulated genes included those involved in serine-type peptidase activity, anatomical structure development, and sensory organ development; downregulated genes included those involved in the structural constituents of the ribosome and ribosome processes. Genes strongly upregulated in response to heavy grazing pressure included adaptive genes such as those encoding ankyrin repeat domain-containing protein and HSP. These findings improve our understanding of the role of the transcriptome in C. albonemus population response to livestock grazing and may provide useful targets for grasshopper control.

  3. The Impact of Analog and Bang-Bang Steering Gear Control on Ship's Fuel Economy

    DEFF Research Database (Denmark)

    Nørtoft Thomsen, J. C.; Blanke, Mogens; Reid, R. E.

    1982-01-01

    it is found to be at least equally important regarding steering performance and fuel economy. The paper presents a comprehensive survey of steering gear principles commonly used, including relevant details of three analog steering gear servo principles, which have outperformed conventional designs. Control......The latest years have shown considerable efforts towards improving steering generated propulsion losses of ships by the introduction of various sophisticated control algorithms in the autopilots. However, little previous attention has been given to the steering gear control loop, although...

  4. Reproductive performance of ewes grazing lucerne during different periods around mating.

    Science.gov (United States)

    Robertson, S M; Clayton, E H; Friend, M A

    2015-11-01

    High intake of lucerne pastures or feeding of other high quality diets during early pregnancy may increase embryo mortality, negating any benefit of improved nutrition on ovulation rate in ewes. This study was conducted to determine whether grazing ewes on lucerne (Medicago sativa) pastures for 7 days prior to and throughout joining would result in greater foetal numbers than if ewes were removed 7 days after the commencement of joining, or if ewes grazed senescent pasture throughout the joining period. Merino ewes (300) were allocated to two replicates of three treatments, grazing pastures between Days -7 and 36 of an unsynchronised, natural autumn joining. Grazing lucerne to Day 7 of joining resulted in 30% more (Pewe than grazing senescent pasture (1.60±0.07 and 1.31±0.07, respectively), and 19% more lambs marked per ewe joined. Extending grazing of lucerne past Day 7 of joining did not result in additional foetuses per ewe (1.61±0.06) in comparison with only grazing lucerne to Day 7 of joining. Greater than 80% of ewes mated during the first 14 days of joining, and the proportions of ewes returning to oestrus and re-mating (0.18±0.022) and of non-pregnant (0.09±0.017) ewes were similar (P>0.05) among all treatment groups, suggesting no differences between treatments in embryo mortality. Grazing naturally cycling ewes on lucerne prior to and during joinings in autumn is recommended as a means to increase the number of lambs born, although additional gains may not be obtained by grazing past day seven of joining. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Violation of Continuous-Variable Einstein-Podolsky-Rosen Steering with Discrete Measurements

    Science.gov (United States)

    Schneeloch, James; Dixon, P. Ben; Howland, Gregory A.; Broadbent, Curtis J.; Howell, John C.

    2013-03-01

    In this Letter, we derive an entropic Einstein-Podolsky-Rosen (EPR) steering inequality for continuous-variable systems using only experimentally measured discrete probability distributions and details of the measurement apparatus. We use this inequality to witness EPR steering between the positions and momenta of photon pairs generated in spontaneous parametric down-conversion. We examine the asymmetry between parties in this inequality, and show that this asymmetry can be used to reduce the technical requirements of experimental setups intended to demonstrate the EPR paradox. Furthermore, we develop a more stringent steering inequality that is symmetric between parties, and use it to show that the down-converted photon pairs also exhibit symmetric EPR steering.

  6. Steers performance in dwarf elephant grass pastures alone or mixed with Arachis pintoi.

    Science.gov (United States)

    Crestani, Steben; Ribeiro Filho, Henrique Mendonça Nunes; Miguel, Marcolino Frederico; de Almeida, Edison Xavier; Santos, Flávio Augusto Portela

    2013-08-01

    The inclusion of legumes in pasture reduces the need for mineral nitrogen applications and the pollution of groundwater; however, the agronomic and animal husbandry advantages with tropical legumes are still little known. The objective of this study was to quantify the effect of the use of forage peanut (Arachis pintoi cv. Amarillo) in dwarf elephant grass pastures (Pennisetum purpureum cv. BRS Kurumi) on forage intake and animal performance. The experimental treatments were dwarf elephant grass fertilized with 200 kg N/ha, and dwarf elephant grass mixed with forage peanut without mineral fertilizers. The animals used for the experiment were 12 Charolais steers (body weight (BW) = 288 ± 5.2 kg) divided into four lots (two per treatment). Pastures were managed under intermittent stocking with an herbage allowance of 5.4 kg dry matter of green leaves/100 kg BW. Dry matter intake (mean = 2.44% BW), the average daily gain (mean = 0.76 kg), and the stocking rate (mean = 3.8 AU/ha) were similar between the studied pastures, but decreased drastically in last grazing cycle with the same herbage allowance. The presence of peanut in dwarf elephant grass pastures was enough to sustain the stocking rate, but did not allow increasing forage intake and animal performance.

  7. The Front Steering Launcher Design for the ITER ECRH Upper Port

    International Nuclear Information System (INIS)

    Henderson, M A; Chavan, R; Heidinger, R; Nikkola, P; Ramponi, G; Saibene, G; Sanchez, F; Sauter, O; Serikov, A; Zohm, H

    2005-01-01

    The ECRH ITER upper port antenna's role is to stabilize the neoclassical tearing mode (NTM) on either the q = 2 or 3/2 rational flux surfaces, which requires a narrow current deposition profile (j CD ) over a wide range along the resonance surfaces. The width of j CD should be equivalent to the marginal island width to fully stabilise the NTM. Two antenna concepts are under consideration for the upper port launcher: front steering (FS) and remote steering (RS). The FS launcher decouples the steering and focusing aspects using a two mirror system (one focusing and one steering), achieving a wider steering range and higher current density for NTM stabilisation than required by ITER, offering a threefold increase in NTM stabilization efficiency over the RS launcher. The improved physics performance has motivated the further design study of the FS launcher aiming toward a build to print launcher. The present design is compatible with ≥2.0 MW CW operation and 8 beams per port plug. A frictionless backlashfree system is envisioned for the steering mechanism. An overview of the launcher design, the calculated physics performance and the possibility of using the upper port launcher for extended physics applications (beyond NTM stabilisation) are discussed

  8. Wetting front instability in an initially wet unsaturated fracture

    International Nuclear Information System (INIS)

    Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

    1992-01-01

    Experimental results exploring gravity-driven wetting front instability in a pre-wetted, rough-walled analog fracture are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

  9. Wetting front instability in an initially wet unsaturated fracture

    International Nuclear Information System (INIS)

    Nicholl, M.J.; Glass, R.J.; Nguyen, H.A.

    1993-01-01

    Experimental results exploring gravity-driven wetting from instability in a pre-wetted, rough-walled analog fractures such as those at Yucca Mountain are presented. Initial conditions considered include a uniform moisture field wetted to field capacity of the analog fracture and the structured moisture field created by unstable infiltration into an initially dry fracture. As in previous studies performed under dry initial conditions, instability was found to result both at the cessation of stable infiltration and at flux lower than the fracture capacity under gravitational driving force. Individual fingers were faster, narrower, longer, and more numerous than observed under dry initial conditions. Wetting fronts were found to follow existing wetted structure, providing a mechanism for rapid recharge and transport

  10. Impact of Graze-­‐Out in Hard Red Winter Wheat Production

    OpenAIRE

    Neupane, Diwash; Moss, Charles B.

    2014-01-01

    We investigate the relationship between wheat graze-­‐out and cattle-­‐wheat price ratio and moisture level and examine the impact of graze-­‐out on wheat yield in major wheat-­‐producing states in US. Results indicate that cattle-­‐wheat price ratio and moisture level affect farmers’ graze out decision and graze-­‐out have significant impact on wheat yield.

  11. PREFACE: Dynamics of wetting Dynamics of wetting

    Science.gov (United States)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

    2009-11-01

    Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting

  12. 36 CFR 222.53 - Grazing fees in the East-noncompetitive procedures.

    Science.gov (United States)

    2010-07-01

    ... lands and the total costs (other than grazing fee costs) of operating on National Forest System lands... the percentage change in the cost of alternative livestock feed. (3) Computation of Annual Grazing Fee... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Grazing fees in the East...

  13. Effects of Grazing Abandoned Grassland on Herbage Production and Utilization, and Sheep Preference and Performance

    Directory of Open Access Journals (Sweden)

    Håvard Steinshamn

    2018-05-01

    Full Text Available Large areas of farmland are abandoned in Norway, which for various reasons are regarded as undesirable. Loss of farmland may have negative implications for biodiversity and ecosystem function and food production potential. The objectives of this study were to assess forage mass production and utilization, botanical composition, lamb performance, and grazing distribution pattern when reintroducing livestock grazing to an abandoned grassland. The study area was located in Central Norway, unmanaged for 12 years. Sheep grazed the area for 10 weeks in 2013 and 4 weeks in spring and autumn, respectively, in 2014 and 2015. During the summer of 2014 and 2015, the area was subjected to the following replicated treatments: (1 No grazing, (2 grazing with heifers, and (3 grazing with ewes and their offspring. The stocking rate was similar in the grazed treatments. Forage biomass production and animal intake were estimated using grazing exclosure cages and botanical composition by visual assessment. Effect on lamb performance was evaluated by live weight gain and slaughter traits in sheep subjected to three treatments: (1 Common farm procedure with summer range pasturing, (2 spring grazing period extended by 1 month on the abandoned grassland before summer range pasturing, and (3 spring and summer grazing on the abandoned grassland. Grazing distribution patterns were studied using GPS position collars on ewes. Total annual biomass production was on average 72% higher with summer grazing than without. Annual consumption and utilization was on average 218 g DM/m2 and 70% when summer grazed, and 25 g DM/m2 and 18% without grazing, respectively. Botanical composition did not differ between treatments. Live weight gain was higher in lambs subjected to an extended spring grazing period (255 g/d compared to common farm practice (228 g/d and spring and summer grazing on the abandoned grassland (203 g/d, and carcass value was 14% higher in lambs on extended spring

  14. Effects of beef production system on animal performance and carcass characteristics.

    Science.gov (United States)

    Maxwell, C L; Krehbiel, C R; Wilson, B K; Johnson, B T; Bernhard, B C; O'Neill, C F; VanOverbeke, D L; Mafi, G G; Step, D L; Richards, C J

    2014-12-01

    The objective of this study was to evaluate conventional (CONV) and natural (NAT) beef production systems from annual pasture through finishing through grazing. Beef steers (n=180, initial BW=250±19 kg) were assigned randomly to 2 treatments in the pasture phase. Steers were implanted with 40 mg of trenbolone acetate (TBA), 8 mg estradiol, and 29 mg tylosin tartrate (CONV), or received no implant (NAT). Steers on the 2 treatments grazed wheat or cereal rye for 109 d. Conventional steers had an 18.5% improvement in ADG (1.22 vs. 1.03 kg/d, P0.07). The CONV steers ate 6.9% more feed (11.8 vs. 11.0 kg/d, Pcarcass weight gain (1.36 vs. 1.06 kg/d), 18.6% improvement in carcass efficiency (0.115 vs. 0.097, Pcarcass weight was increased by 62 kg (424 vs. 362 kg, Pcarcasses in the upper 2/3 of USDA Choice grade (48.7 vs. 18.7%, Pcarcasses (25.4 vs. 9.3%, Pcarcasses with superior YG and desirable quality grades with both roughage levels.

  15. Feed efficiency differences and reranking in beef steers fed grower and finisher diets.

    Science.gov (United States)

    Durunna, O N; Mujibi, F D N; Goonewardene, L; Okine, E K; Basarab, J A; Wang, Z; Moore, S S

    2011-01-01

    This 3-yr study used 490 steers to determine whether feedlot steers changed their feed efficiency (FE) ranking when fed a grower diet, then a finisher diet. The steers were crossbreds and were between 5 to 7 mo of age. There were 2 feeding periods each year. Within each year, approximately 90 steers had their diet switched from a grower to a finisher diet (feed-swap group), whereas another 90 steers were fed either the grower (grower-fed group) or the finisher (finisher-fed group) diet throughout the feeding trial. Each feeding test lasted for a minimum of 10 wk, and all steers were fed ad libitum. Individual animal feed intakes were collected using the GrowSafe feeding system, and BW were measured every 2 wk. Residual feed intake (RFI), G:F, and Kleiber ratio (KR) were computed at the end of each feeding period. For each measure of efficiency, animals were classified as low, medium, or high based on 0.5 SD from the mean. The majority of steers did not maintain the previous efficiency class in the second period. Approximately 58, 51, and 51% of steers in the feed-swap group, finisher-fed group, and the grower-fed group, respectively, changed their RFI measure by 0.5 SD. A low rank correlation occurred in all test groups but was less in the feed-swap group. Spearman rank correlations between the 2 feeding periods in the feed-swap group were 0.33, 0.20, and 0.31 for RFI, G:F, and KR, respectively. Classifications based on G:F and KR showed that a greater number of steers (P 0.05) between the proportions of individuals that changed or maintained their FE class. In the groups without a feed-swap, there was no difference (P > 0.05) in the proportion of steers that changed or maintained the same FE class for all FE measures. Our results suggest that diet type and feeding period affect the FE ranking in beef steers. A feedlot diet is ideal for evaluating the FE potential of steers for feedlot profitability; however, we suggest that tests involving less dense diets should

  16. Grazing preference and utilization of soil fungi by Folsomia candida (Collembola)

    Science.gov (United States)

    Hedenec, Petr; Frouz, Jan

    2016-04-01

    Soil fungi are important food resources for soil fauna. Here we ask whether the collembolan Folsomia candida shows selectivity in grazing between four saprophytic fungi (Penicillium chrysogenum, Penicillium expansum, Absidia glauca, and Cladosporium herbarum), whether grazing preference corresponds to effects on collembolan reproduction, and whether the effects of fungi on grazing and reproduction depends on the fungal substrate, which included three kinds of litter (Alnus glutinosa, Salix caprea, and Quercus robur) and one kind of agar (yeast extract). On agar, Cladosporium herbarum and Absidia glauca were the most preferred fungi and supported the highest collembolan reproduction. On fungal-colonized litter, grazing preference was more affected by litter type than by fungal species whereas collembolan reproduction was affected by both litter type and fungal species. On fungal-colonized litter, the litter type that was most preferred for grazing did not support the highest reproduction, i.e., there was an inconsistency between food preference and suitability. Alder and willow were preferred over oak for grazing, but alder supported the least reproduction.

  17. Test of Einstein-Podolsky-Rosen steering based on the all-versus-nothing proof.

    Science.gov (United States)

    Wu, Chunfeng; Chen, Jing-Ling; Ye, Xiang-Jun; Su, Hong-Yi; Deng, Dong-Ling; Wang, Zhenghan; Oh, C H

    2014-03-06

    In comparison with entanglement and Bell nonlocality, Einstein-Podolsky-Rosen steering is a newly emerged research topic and in its incipient stage. Although Einstein-Podolsky-Rosen steering has been explored via violations of steering inequalities both theoretically and experimentally, the known inequalities in the literatures are far from well-developed. As a result, it is not yet possible to observe Einstein-Podolsky-Rosen steering for some steerable mixed states. Recently, a simple approach was presented to identify Einstein-Podolsky-Rosen steering based on all-versus-nothing argument, offering a strong condition to witness the steerability of a family of two-qubit (pure or mixed) entangled states. In this work, we show that the all-versus-nothing proof of Einstein-Podolsky-Rosen steering can be tested by measuring the projective probabilities. Through the bound of probabilities imposed by local-hidden-state model, the proposed test shows that steering can be detected by the all-versus-nothing argument experimentally even in the presence of imprecision and errors. Our test can be implemented in many physical systems and we discuss the possible realizations of our scheme with non-Abelian anyons and trapped ions.

  18. [Wet work].

    Science.gov (United States)

    Kieć-Swierczyńska, Marta; Chomiczewska, Dorota; Krecisz, Beata

    2010-01-01

    Wet work is one of the most important risk factors of occupational skin diseases. Exposure of hands to the wet environment for more than 2 hours daily, wearing moisture-proof protective gloves for a corresponding period of time or necessity to wash hands frequently lead to the disruption of epidermal stratum corneum, damage to skin barrier function and induction of irritant contact dermatitis. It may also promote penetration of allergens into the skin and increase the risk of sensitization to occupational allergens. Exposure to wet work plays a significant role in occupations, such as hairdressers and barbers, nurses and other health care workers, cleaning staff, food handlers and metalworkers. It is more common among women because many occupations involving wet work are female-dominated. The incidence of wet-work-induced occupational skin diseases can be reduced by taking appropriate preventive measures. These include identification of high-risk groups, education of workers, organization of work enabling to minimize the exposure to wet work, use of personal protective equipment and skin care after work.

  19. Novel Microstrip Patch Antennas with Frequency Agility, Polarization Reconfigurability, Dual Null Steering Capability and Phased Array Antenna with Beam Steering Performance

    Science.gov (United States)

    Babakhani, Behrouz

    Nowadays the wireless communication technology is playing an important role in our daily life. People use wireless devices not only as a conventional communication device but also as tracking and navigation tool, web browsing tool, data storage and transfer tool and so for many other reasons. Based on the user demand, wireless communication engineers try to accommodate as many as possible wireless systems and applications in a single device and therefore, creates a multifunctional device. Antenna, as an integral part of any wireless communication systems, should also be evolved and adjusted with development of wireless transceiver systems. Therefore multifunctional antennas have been introduced to support and enhance the functionality on modern wireless systems. The main focus and contribution of this thesis is design of novel multifunctional microstrip antennas with frequency agility, polarization reconfigurablity, dual null steering capability and phased array antenna with beam steering performance. In this thesis, first, a wide bandwidth(1.10 GHz to 1.60 GHz) right-handed circularly polarized (RHCP) directional antenna for global positioning system (GPS) satellite receive application has been introduced which covers all the GPS bands starting from L1 to L5. This design consists of two crossed bow-tie dipole antennas fed with sequentially phase rotated feed network backed with an artificial high impedance surface (HIS) structure to generate high gain directional radiation patterns. This design shows good CP gain and axial ratio (AR) and wide beamwidth performance. Although this design has good radiation quality, the size and the weight can be reduced as future study. In the second design, a frequency agile antenna was developed which also covers the L-band (L1 to L5) satellite communication frequencies. This frequency agile antenna was designed and realized by new implementation of varactor diodes in the geometry of a circular patch antenna. Beside wide frequency

  20. Grazing exit versus grazing incidence geometry for x-ray absorption near edge structure analysis of arsenic traces

    International Nuclear Information System (INIS)

    Meirer, F.; Streli, C.; Wobrauschek, P.; Zoeger, N.; Pepponi, G.

    2009-01-01

    In the presented study the grazing exit x-ray fluorescence was tested for its applicability to x-ray absorption near edge structure analysis of arsenic in droplet samples. The experimental results have been compared to the findings of former analyses of the same samples using a grazing incidence (GI) setup to compare the performance of both geometries. Furthermore, the investigations were accomplished to gain a better understanding of the so called self-absorption effect, which was observed and investigated in previous studies using a GI geometry. It was suggested that a normal incidence-grazing-exit geometry would not suffer from self-absorption effects in x-ray absorption fine structure (XAFS) analysis due to the minimized path length of the incident beam through the sample. The results proved this assumption and in turn confirmed the occurrence of the self-absorption effect for GI geometry. Due to its lower sensitivity it is difficult to apply the GE geometry to XAFS analysis of trace amounts (few nanograms) of samples but the technique is well suited for the analysis of small amounts of concentrated samples

  1. Design of Model-based Controller with Disturbance Estimation in Steer-by-wire System

    Directory of Open Access Journals (Sweden)

    Jung Sanghun

    2018-01-01

    Full Text Available The steer-by-wire system is a next generation steering control technology that has been actively studied because it has many advantages such as fast response, space efficiency due to removal of redundant mechanical elements, and high connectivity with vehicle chassis control, such as active steering. Steer-by-wire system has disturbance composed of tire friction torque and self-aligning torque. These disturbances vary widely due to the weight or friction coefficient change. Therefore, disturbance compensation logic is strongly required to obtain desired performance. This paper proposes model-based controller with disturbance compensation to achieve the robust control performance. Targeted steer-by-wire system is identified through the experiment and system identification method. Moreover, model-based controller is designed using the identified plant model. Disturbance of targeted steer-by-wire is estimated using disturbance observer(DOB, and compensate the estimated disturbance into control input. Experiment of various scenarios are conducted to validate the robust performance of proposed model-based controller.

  2. On Optimizing Steering Performance of Multi-axle Vehicle Based on Driving Force Control

    Directory of Open Access Journals (Sweden)

    Wu Zhicheng

    2017-01-01

    Full Text Available The steering performance of multi-axle vehicle with independent driving system is affected by the distribution of the wheel driving force. A nonlinear vehicle dynamics model including magic formula tire model for describing 11 DoF four-axle vehicle with dual-front-axle-steering (DFAS system was presented. The influence of different driving force distribution scheme on the steering performance of the vehicle was analyzed. A control strategy for improving the steady response and transient response of the vehicle steering is proposed. The results show: For the steady response, setting different drive force for internal and external wheels according to the actual steering characteristics of the vehicle can effectively improve its steering characteristics; For the transient response, adopting the zero sideslip angle control strategy and using the PID control algorithm to control the driving force of the outside wheel of tear-two-axle, under angle step input, the vehicle sideslip angle can quickly stabilize to 0 and yaw rate also significantly decreases.

  3. A Vehicle Steering Recognition System Based on Low-Cost Smartphone Sensors

    Directory of Open Access Journals (Sweden)

    Xinhua Liu

    2017-03-01

    Full Text Available Recognizing how a vehicle is steered and then alerting drivers in real time is of utmost importance to the vehicle and driver’s safety, since fatal accidents are often caused by dangerous vehicle maneuvers, such as rapid turns, fast lane-changes, etc. Existing solutions using video or in-vehicle sensors have been employed to identify dangerous vehicle maneuvers, but these methods are subject to the effects of the environmental elements or the hardware is very costly. In the mobile computing era, smartphones have become key tools to develop innovative mobile context-aware systems. In this paper, we present a recognition system for dangerous vehicle steering based on the low-cost sensors found in a smartphone: i.e., the gyroscope and the accelerometer. To identify vehicle steering maneuvers, we focus on the vehicle’s angular velocity, which is characterized by gyroscope data from a smartphone mounted in the vehicle. Three steering maneuvers including turns, lane-changes and U-turns are defined, and a vehicle angular velocity matching algorithm based on Fast Dynamic Time Warping (FastDTW is adopted to recognize the vehicle steering. The results of extensive experiments show that the average accuracy rate of the presented recognition reaches 95%, which implies that the proposed smartphone-based method is suitable for recognizing dangerous vehicle steering maneuvers.

  4. Genetic strain and diet effects on grazing behavior, pasture intake, and milk production.

    Science.gov (United States)

    Sheahan, A J; Kolver, E S; Roche, J R

    2011-07-01

    Understanding how dairy cows adjust their grazing behavior in response to feed supplements is important for the development of management strategies that optimize profit from supplementation. New Zealand Holstein-Friesian (HF) cows have been selected for milk production on a predominantly pasture-based diet; in comparison, HF cows of North American (NA) ancestry have been selected almost exclusively for milk yield and fed diets high in nonfiber carbohydrates (NFC). We hypothesized, therefore, that supplementation would have differing effects on grazing behavior, pasture dry matter intake (DMI), and milk production in these genetic strains at peak, mid, and late lactation. A study was conducted over 2 consecutive lactations, with NA and NZ cows randomly allocated at calving to 0, 3, or 6 kg of dry matter/day concentrate plus unrestricted access to pasture. Pasture DMI, milk production, and grazing behavior were recorded at peak, mid, and late lactation. Concentrates were fed in equal amounts at morning and afternoon milking. The NA cows produced more milk and milk components, and had a greater pasture DMI, despite spending less time grazing. Declines in time spent grazing and pasture DMI were associated with increasing concentrate DMI. Grazing behavior following morning supplementation was different from that recorded following afternoon supplementation. Grazing ceased following morning supplementation before rumen fill could be a limiting factor, and the length of the grazing interval was inversely proportional to the amount of concentrate offered; these results suggest that physiological rather than physical stimuli were responsible for grazing cessation. The decrease in time spent grazing with increasing concentrate DMI is consistent with changes in neuroendocrine factors secreted in response to the presence of food in the digestive tract or with circulating products of digestion. After afternoon supplementation, sunset signaled the end of grazing irrespective of

  5. Changes in semi-arid plant species associations along a livestock grazing gradient.

    Directory of Open Access Journals (Sweden)

    Hugo Saiz

    Full Text Available In semi-arid ecosystems, vegetation is heterogeneously distributed, with plant species often associating in patches. These associations between species are not constant, but depend on the particular response of each species to environmental factors. Here, we investigated how plant species associations change in response to livestock grazing in a semi-arid ecosystem, Cabo de Gata-Níjar Natural Park in South East Spain. We established linear point-intercept transects at four sites with different grazing intensity, and recorded all species at each point. We investigated plant associations by comparing the number of times that each pair of species occurred at the same spatial point (co-occurrences, with the expected number of times based on species abundances. We also assessed associations for each shrub and grass species by considering all their pairs of associations and for the whole plant community by considering all pairs of associations on each site. At all sites, the plant community had a negative pattern of association, with fewer co-occurrences than expected. Negative association in the plant community increased at maximum grazing intensity. Most species associated as expected, particularly grass species, and positive associations were most important at intermediate grazing intensities. No species changed its type of association along the grazing gradient. We conclude that in the present plant community, grazing-resistant species compete among themselves and segregate in space. Some shrub species act as refuges for grazing-sensitive species that benefit from being spatially associated with shrub species, particularly at intermediate grazing intensities where positive associations were highest. At high grazing intensity, these shrubs can no longer persist and positive associations decrease due to the disappearance of refuges. Spatial associations between plant species and their response to grazing help identify the factors that organize

  6. Morphogenesis in guinea grass pastures under rotational grazing strategies

    Directory of Open Access Journals (Sweden)

    Denise Baptaglin Montagner

    2012-04-01

    Full Text Available This study was conducted in order to evaluate the morphogenetic and structural characteristics of guinea grass cv. Mombasa under three post-grazing heights (intense - 30 cm, lenient - 50 cm and variable - 50 in spring-summer and 30 cm in autumn-winter when sward light interception reached 95% during regrowth. Post-grazing heights were allocated to experimental units (0.25 ha in a completely randomized block design with three replications. Post-grazing heights affected only leaf elongation rate and the number of live leaves. Pastures managed with variable post-grazing height showed higher leaf elongation rate in the summer of 2007. This management strategy also resulted in a higher number of live leaves. During the spring of 2006, plants showed lower leaf elongation rate, leaf appearance rate and number of live leaves, and greater phyllochron and leaf lifespan. In contrast, during the summer of 2007, the leaf appearance rate, leaf elongation rate, number of live leaves, and final leaf length were greater while phyllochron, stem elongation rate, and leaf senescence rate were lower. The management of the guinea grass cv. Mombasa with intense or variable post-grazing height throughout the year seems to represent an interesting management target, in terms of leaf appearance rate and number of live leaves.

  7. Body composition and net and dietary macrominerals requirements of Nellore steers under grazing Composição corporal e exigências líquidas e dietéticas de macrominerais de bovinos Nelore castrados em pastejo

    Directory of Open Access Journals (Sweden)

    Vitor Visintin Silva de Almeida

    2009-06-01

    Full Text Available This experiment was carried out with the objective of determining the macrominerals (Ca, P, Mg, K and Na requirements of Nellore steers under grazing. Twenty four Nellore steers (371 ± 14 kg of BW and 26 mo old were used. Four steers were slaughtered at the beginning of the experiment (reference group, serving as a reference in subsequent study. The remaining 20 animals were weighed and distributed into a completely randomized design with four supplementation levels offer: 0.0 (mineral mixture - control, 0.3, 0.6 and 0.9% of BW, with five replications. The supplements, based on ground corn, soybean meal and/or urea, were previously balanced to achieve an average daily gain of 350, 650 and 850g, respectively, for the different supplementation levels offer. The contents of macrominerals retained in the animal body were determined by regression equations of the macrominerals body content logarithm in function of the empty body weight logarithm (EBW. Net macrominerals requirements for a gain of 1kg of EBW were obtained using the equation Y'= b.10ª.Xb-1, with a and b, respectively, the intercept and the regression coefficient of the prediction equations of macrominerals in the animal body contents for each macromineral considered. The concentrations of all macrominerals, in the empty body weight and gain of the empty body weight, decreased with the increase in the body weight. Total calcium and phosphorus dietary requirements are higher than those recommended in the literature.Com o objetivo de determinar as exigências de macrominerais (Ca, P, Mg, K e Na de bovinos Nelore castrados sob pastejo, foi conduzido um experimento com 24 novilhos da raça Nelore, castrados, com peso inicial de 371 ± 14 kg e 26 meses de idade. Quatro novilhos foram abatidos no início do experimento (grupo referência para servir de referência nos estudos subsequentes. Os animais restantes (20 foram pesados e distribuídos em delineamento inteiramente casualizado com

  8. An investigation on motor-driven power steering-based crosswind disturbance compensation for the reduction of driver steering effort

    Science.gov (United States)

    Kim, Kyuwon; Kim, Boemjun; Go, Youngil; Park, Jaeyong; Park, Joonhong; Suh, Insoo; Yi, Kyongsu

    2014-07-01

    This paper describes a lateral disturbance compensation algorithm for an application to a motor-driven power steering (MDPS)-based driver assistant system. The lateral disturbance including wind force and lateral load transfer by bank angle reduces the driver's steering refinement and at the same time increases the possibility of an accident. A lateral disturbance compensation algorithm is designed to determine the motor overlay torque of an MDPS system for reducing the manoeuvreing effort of a human driver under lateral disturbance. Motor overlay torque for the compensation of driver's steering torque induced by the lateral disturbance consists of human torque feedback and feedforward torque. Vehicle-driver system dynamics have been investigated using a combined dynamic model which consists of a vehicle dynamic model, driver steering dynamic model and lateral disturbance model. The human torque feedback input has been designed via the investigation of the vehicle-driver system dynamics. Feedforward input torque is calculated to compensate additional tyre self-aligning torque from an estimated lateral disturbance. The proposed compensation algorithm has been implemented on a developed driver model which represents the driver's manoeuvreing characteristics under the lateral disturbance. The developed driver model has been validated with test data via a driving simulator in a crosswind condition. Human-in-the-loop simulations with a full-scale driving simulator on a virtual test track have been conducted to investigate the real-time performance of the proposed lateral disturbance compensation algorithm. It has been shown from simulation studies and human-in-the-loop simulation results that the driver's manoeuvreing effort and a lateral deviation of the vehicle under the lateral disturbance can be significantly reduced via the lateral disturbance compensation algorithm.

  9. Environmental Assessment of Beale AFB Grazing Lease Program

    Science.gov (United States)

    2012-12-01

    Beale AFB will use livestock (cattle, sheep and goats ) on its properties throughout the year as needed for the control of noxious weeds, reduction...initiating a wildfire. California Farm Bureau Federation policy recognizes that grazing is the most practical and environmentally acceptable way to...Site Monitoring Well Installation and Annual Targeted Goat Grazing Project, Placer County, California. 21 September 2011.  

  10. Demonstration of Einstein-Podolsky-Rosen steering with enhanced subchannel discrimination

    Science.gov (United States)

    Sun, Kai; Ye, Xiang-Jun; Xiao, Ya; Xu, Xiao-Ye; Wu, Yu-Chun; Xu, Jin-Shi; Chen, Jing-Ling; Li, Chuan-Feng; Guo, Guang-Can

    2018-03-01

    Einstein-Podolsky-Rosen (EPR) steering describes a quantum nonlocal phenomenon in which one party can nonlocally affect the other's state through local measurements. It reveals an additional concept of quantum non-locality, which stands between quantum entanglement and Bell nonlocality. Recently, a quantum information task named as subchannel discrimination (SD) provides a necessary and sufficient characterization of EPR steering. The success probability of SD using steerable states is higher than using any unsteerable states, even when they are entangled. However, the detailed construction of such subchannels and the experimental realization of the corresponding task are still technologically challenging. In this work, we designed a feasible collection of subchannels for a quantum channel and experimentally demonstrated the corresponding SD task where the probabilities of correct discrimination are clearly enhanced by exploiting steerable states. Our results provide a concrete example to operationally demonstrate EPR steering and shine a new light on the potential application of EPR steering.

  11. Effect of grazing frequency and intensity on Lolium perenne L ...

    African Journals Online (AJOL)

    ) system. Low frequency, low intensity grazing produced lower CDMD and herbage N levels than higher grazing frequencies and intensities. These differences were, however, generally small. Overall, levels of herbage digestibility (estimated ...

  12. An agent-based model of cattle grazing toxic Geyer's larkspur.

    Science.gov (United States)

    Jablonski, Kevin E; Boone, Randall B; Meiman, Paul J

    2018-01-01

    By killing cattle and otherwise complicating management, the many species of larkspur (Delphinium spp.) present a serious, intractable, and complex challenge to livestock grazing management in the western United States. Among the many obstacles to improving our understanding of cattle-larkspur dynamics has been the difficulty of testing different grazing management strategies in the field, as the risk of dead animals is too great. Agent-based models (ABMs) provide an effective method of testing alternate management strategies without risk to livestock. ABMs are especially useful for modeling complex systems such as livestock grazing management, and allow for realistic bottom-up encoding of cattle behavior. Here, we introduce a spatially-explicit, behavior-based ABM of cattle grazing in a pasture with a dangerous amount of Geyer's larkspur (D. geyeri). This model tests the role of herd cohesion and stocking density in larkspur intake, finds that both are key drivers of larkspur-induced toxicosis, and indicates that alteration of these factors within realistic bounds can mitigate risk. Crucially, the model points to herd cohesion, which has received little attention in the discipline, as playing an important role in lethal acute toxicosis. As the first ABM to model grazing behavior at realistic scales, this study also demonstrates the tremendous potential of ABMs to illuminate grazing management dynamics, including fundamental aspects of livestock behavior amidst ecological heterogeneity.

  13. Stochastic stability of four-wheel-steering system

    International Nuclear Information System (INIS)

    Huang Dongwei; Wang Hongli; Zhu Zhiwen; Feng Zhang

    2007-01-01

    A four-wheel-steering system subjected to white noise excitations was reduced to a two-degree-of-freedom quasi-non-integrable-Hamiltonian system. Subsequently we obtained an one-dimensional Ito stochastic differential equation for the averaged Hamiltonian of the system by using the stochastic averaging method for quasi-non-integrable-Hamiltonian systems. Thus, the stochastic stability of four-wheel-steering system was analyzed by analyzing the sample behaviors of the averaged Hamiltonian at the boundary H = 0 and calculating its Lyapunov exponent. An example given at the end demonstrated that the conclusion obtained is of considerable significance

  14. Grazing exclusion, substrate type, and drought frequency affect plant community structure in rangelands of the arid unpredictable Arabian Deserts

    Science.gov (United States)

    El-Keblawy, Ali; El-Sheikh, Mohamed

    2017-04-01

    Grazing and drought can adversely affect the ecology and management of rangeland ecosystems. Several management actions have been applied to restore species diversity and community structure in degraded rangelands of the unpredictable arid environment. Protection from grazing is considered as a proper approach for restoration of degraded rangelands, but this depends on substrate type and sometime is hindered with water deficiency (drought). In this study, the effect of protection from grazing animals on species diversity and plant community structure was assessed after a dry and wet periods in both sandy and gravelly substrates in the Dubai Desert Conservation reserve (DDCR), United Arab Emirates. Two sites were selected during November 2012 on the two substrate types (fixed sandy flat and gravel plain) in the arid DDCR. An enclosure was established in each site. Plant community attributes (plant cover, density, frequency, species composition, and diversity indices) were assessed in a number of permanent plots laid inside and outside each enclosure during November 2012, April 2014 and April 2016. The results showed that protection improved clay content, but decreased the organic matters. Interestingly, the protection reduced the concentrations of most estimated nutrients, which could be attributed to the high turnover rate of nutrients associated grazing and low decomposition of accumulated dry plants of non-protected sites. Protection significantly increased all plant community attributes, but the only significant effect was for plant density. Plant density was almost twice greater inside than outside the enclosures. During the dry period, protection resulted in significantly greater deterioration in cover, density and all diversity indices in gravel, compared to sandy sites. Most of the grasses and shrubby plants had died in the gravel plains. However, plant community of the gravel plains was significantly restored after receiving considerable rainfalls. The

  15. Ultra-compact laser beam steering device using holographically formed two dimensional photonic crystal.

    Science.gov (United States)

    Dou, Xinyuan; Chen, Xiaonan; Chen, Maggie Yihong; Wang, Alan Xiaolong; Jiang, Wei; Chen, Ray T

    2010-03-01

    In this paper, we report the theoretical study of polymer-based photonic crystals for laser beam steering which is based on the superprism effect as well as the experiment fabrication of the two dimensional photonic crystals for the laser beam steering. Superprism effect, the principle for beam steering, was separately studied in details through EFC (Equifrequency Contour) analysis. Polymer based photonic crystals were fabricated through double exposure holographic interference method using SU8-2007. The experiment results showed a beam steering angle of 10 degree for 30 nm wavelength variation.

  16. Comparison of 3 tall fescue-based stocker systems.

    Science.gov (United States)

    Bailey, N J; Kallenbach, R L

    2010-05-01

    A 2-yr production study was conducted to evaluate 3 systems of growing stocker calves under rotational stocking. One group of steers was stocked on pasture from early April to mid August (spring-stocked steers = SSS), and another group of steers was stocked from early July to late October (fall-stocked steers = FSS). Steers were stratified by BW (n = 72, BW = 229 +/- 11 kg for SSS; n = 72, BW = 248 +/- 18 kg for FSS) and randomly assigned to 1 of 3 treatments. The 3 treatments were 1) rotationally stocked only (control; CON), steers rotated to a new paddock as forage availability dropped below acceptable levels in the occupied paddock; 2) rotationally stocked with distillers grains (DIST); this was the same as CON except steers were supplemented with varying amounts of distillers dried grains with solubles (DDGS) based on forage nutritive value; and 3) rotationally stocked with round-bale silage (SIL); excess forage in spring was harvested and stored as round-bale silage and fed back as needed. Total BW gain/ha over the entire grazing season did not differ between DIST and SIL (P = 0.09) steers, but both were greater than CON (P forage nutritive value resulted in consistent BW gains throughout the grazing study, whereas steers in the SIL and CON treatments gained less BW during the latter portion of the season. Controlling forage maturity by removal in the SIL treatment resulted in total BW gains/ha that were not different than the DIST treatment.

  17. Loophole-free Einstein-Podolsky-Rosen experiment via quantum steering

    International Nuclear Information System (INIS)

    Wittmann, Bernhard; Ramelow, Sven; Zeilinger, Anton; Steinlechner, Fabian; Langford, Nathan K; Ursin, Rupert; Brunner, Nicolas; Wiseman, Howard M

    2012-01-01

    Tests of the predictions of quantum mechanics for entangled systems have provided increasing evidence against local realistic theories. However, there remains the crucial challenge of simultaneously closing all major loopholes—the locality, freedom-of-choice and detection loopholes—in a single experiment. An important sub-class of local realistic theories can be tested with the concept of ‘steering’. The term ‘steering’ was introduced by Schrödinger in 1935 for the fact that entanglement would seem to allow an experimenter to remotely steer the state of a distant system as in the Einstein-Podolsky-Rosen (EPR) argument. Einstein called this ‘spooky action at a distance’. EPR-steering has recently been rigorously formulated as a quantum information task opening it up to new experimental tests. Here, we present the first loophole-free demonstration of EPR-steering by violating three-setting quadratic steering inequality, tested with polarization-entangled photons shared between two distant laboratories. Our experiment demonstrates this effect while simultaneously closing all loopholes: both the locality loophole and a specific form of the freedom-of-choice loophole are closed by having a large separation of the parties and using fast quantum random number generators, and the fair-sampling loophole is closed by having high overall detection efficiency. Thereby, we exclude—for the first time loophole-free—an important class of local realistic theories considered by EPR. Besides its foundational importance, loophole-free steering also allows the distribution of quantum entanglement secure event in the presence of an untrusted party. (paper)

  18. Loophole-free Einstein-Podolsky-Rosen experiment via quantum steering

    Science.gov (United States)

    Wittmann, Bernhard; Ramelow, Sven; Steinlechner, Fabian; Langford, Nathan K.; Brunner, Nicolas; Wiseman, Howard M.; Ursin, Rupert; Zeilinger, Anton

    2012-05-01

    Tests of the predictions of quantum mechanics for entangled systems have provided increasing evidence against local realistic theories. However, there remains the crucial challenge of simultaneously closing all major loopholes—the locality, freedom-of-choice and detection loopholes—in a single experiment. An important sub-class of local realistic theories can be tested with the concept of ‘steering’. The term ‘steering’ was introduced by Schrödinger in 1935 for the fact that entanglement would seem to allow an experimenter to remotely steer the state of a distant system as in the Einstein-Podolsky-Rosen (EPR) argument. Einstein called this ‘spooky action at a distance’. EPR-steering has recently been rigorously formulated as a quantum information task opening it up to new experimental tests. Here, we present the first loophole-free demonstration of EPR-steering by violating three-setting quadratic steering inequality, tested with polarization-entangled photons shared between two distant laboratories. Our experiment demonstrates this effect while simultaneously closing all loopholes: both the locality loophole and a specific form of the freedom-of-choice loophole are closed by having a large separation of the parties and using fast quantum random number generators, and the fair-sampling loophole is closed by having high overall detection efficiency. Thereby, we exclude—for the first time loophole-free—an important class of local realistic theories considered by EPR. Besides its foundational importance, loophole-free steering also allows the distribution of quantum entanglement secure event in the presence of an untrusted party.

  19. Grazing effects on species composition in different vegetation types (La Palma, Canary Islands)

    Science.gov (United States)

    Arévalo, J. R.; de Nascimento, L.; Fernández-Lugo, S.; Mata, J.; Bermejo, L.

    2011-05-01

    Grazing management is probably one of the most extensive land uses, but its effects on plant communities have in many cases been revealed to be contradictory. Some authors have related these contradictions to the stochastic character of grazing systems. Because of that, it is necessary to implement specific analyses of grazing effects on each community, especially in natural protected areas, in order to provide the best information to managers. We studied the effects of grazing on the species composition of the main vegetation types where it takes place (grasslands, shrublands and pine forests) on the island of La Palma, Canary Islands. We used the point-quadrat intersect method to study the species composition of grazed and ungrazed areas, which also were characterized by their altitude, distance to farms, distance to settlements, year of sampling, herbaceous aboveground biomass and soil organic matter. The variables organic matter, productivity and species richness were not significantly affected by grazing. The species composition of the analyzed plant communities was affected more by variables such as altitude or distance to farms than by extensive grazing that has been traditionally carried out on the island of La Palma involving certain practices such as continuous monitoring of animals by goat keepers, medium stocking rates adjusted to the availability of natural pastures, supplementation during the dry season using local forage shrubs or mown pastures and rotating animals within grazing areas Although some studies have shown a negative effect of grazing on endangered plant species, these results cannot be freely extrapolated to the traditional grazing systems that exert a low pressure on plant communities (as has been found in this study). We consider extensive grazing as a viable way of ensuring sustainable management of the studied ecosystems.

  20. Density and success of bird nests relative to grazing on western Montana grasslands

    Science.gov (United States)

    Fondell, Thomas F.; Ball, I.J.

    2004-01-01

    Grassland birds are declining at a faster rate than any other group of North American bird species. Livestock grazing is the primary economic use of grasslands in the western United States, but the effects of this use on distribution and productivity of grassland birds are unclear. We examined nest density and success of ground-nesting birds on grazed and ungrazed grasslands in western Montana. In comparison to grazed plots, ungrazed plots had reduced forb cover, increased litter cover, increased litter depth, and increased visual obstruction readings (VOR) of vegetation. Nest density among 10 of 11 common bird species was most strongly correlated with VOR of plots, and greatest nest density for each species occurred where mean VOR of the plot was similar to mean VOR at nests. Additionally, all bird species were relatively consistent in their choice of VOR at nests despite substantial differences in VOR among plots. We suggest that birds selected plots based in part on availability of suitable nest sites and that variation in nest density relative to grazing reflected the effect of grazing on availability of nest sites. Nest success was similar between grazed plots and ungrazed plots for two species but was lower for nests on grazed plots than on ungrazed plots for two other species because of increased rates of predation, trampling, or parasitism by brown-headed cowbirds (Molothrus ater). Other species nested almost exclusively on ungrazed plots (six species) or grazed plots (one species), precluding evaluation of the effects of grazing on nest success. We demonstrate that each species in a diverse suite of ground-nesting birds preferentially used certain habitats for nesting and that grazing altered availability of preferred nesting habitats through changes in vegetation structure and plant species composition. We also show that grazing directly or indirectly predisposed some bird species to increased nesting mortality. Management alternatives that avoid

  1. The influence of grazing on surface climatological variables of tallgrass prairie. Final Technical Report

    International Nuclear Information System (INIS)

    Seastedt, T.R.; Dyer, M.I.; Turner, C.L.

    1992-01-01

    Mass and energy exchange between most grassland canopies and the atmosphere are mediated by grazing activities. Ambient temperatures can be increased or decreased by grazers. Data have been assembled from simulated grazing experiments on Konza Prairie Research Natural Area and observations on adjacent pastures grazed by cattle show significant changes in primary production, nutrient content, and bidirectional reflectance characteristics as a function of grazing intensity. The purpose of this research was to provide algorithms that would allow incorporation of grazing effects into models of energy budgets using remote sensing procedures. The approach involved: (1) linking empirical measurements of plant biomass and grazing intensities to remotely sensed canopy reflectance, and (2) using a higher resolution, mechanistic grazing model to derive plant ecophysiological parameters that influence reflectance and other surface climatological variables

  2. Dissipation induced asymmetric steering of distant atomic ensembles

    Science.gov (United States)

    Cheng, Guangling; Tan, Huatang; Chen, Aixi

    2018-04-01

    The asymmetric steering effects of separated atomic ensembles denoted by the effective bosonic modes have been explored by the means of quantum reservoir engineering in the setting of the cascaded cavities, in each of which an atomic ensemble is involved. It is shown that the steady-state asymmetric steering of the mesoscopic objects is unconditionally achieved via the dissipation of the cavities, by which the nonlocal interaction occurs between two atomic ensembles, and the direction of steering could be easily controlled through variation of certain tunable system parameters. One advantage of the present scheme is that it could be rather robust against parameter fluctuations, and does not require the accurate control of evolution time and the original state of the system. Furthermore, the double-channel Raman transitions between the long-lived atomic ground states are used and the atomic ensembles act as the quantum network nodes, which makes our scheme insensitive to the collective spontaneous emission of atoms.

  3. Einstein-Podolsky-Rosen-steering swapping between two Gaussian multipartite entangled states

    Science.gov (United States)

    Wang, Meihong; Qin, Zhongzhong; Wang, Yu; Su, Xiaolong

    2017-08-01

    Multipartite Einstein-Podolsky-Rosen (EPR) steering is a useful quantum resource for quantum communication in quantum networks. It has potential applications in secure quantum communication, such as one-sided device-independent quantum key distribution and quantum secret sharing. By distributing optical modes of a multipartite entangled state to space-separated quantum nodes, a local quantum network can be established. Based on the existing multipartite EPR steering in a local quantum network, secure quantum communication protocol can be accomplished. In this manuscript, we present swapping schemes for EPR steering between two space-separated Gaussian multipartite entangled states, which can be used to connect two space-separated quantum networks. Two swapping schemes, including the swapping between a tripartite Greenberger-Horne-Zeilinger (GHZ) entangled state and an EPR entangled state and that between two tripartite GHZ entangled states, are analyzed. Various types of EPR steering are presented after the swapping of two space-separated independent multipartite entanglement states without direct interaction, which can be used to implement quantum communication between two quantum networks. The presented schemes provide technical reference for more complicated quantum networks with EPR steering.

  4. Sources of carbohydrates in the ingestive behavior of feedlot steers

    Directory of Open Access Journals (Sweden)

    Viviane Santos da Silva

    2014-05-01

    Full Text Available In this article we research the influence of different sources of carbohydrates (corn, soybean hulls or wheat bran upon the digestive behavior of 24 confined castrated steers with an initial average age and weight of 20 months and 330 kg born from the cross between Charolais and Nellore. The diet was composed of 40% sorghum silage and 60% concentrate. The time spent on total ruminating (an average of 454.6 min/day was not influenced by the source of carbohydrate. The animals from the wheat bran treatment spent less time idle (718 min in relation to those on the corn and soybean hulls treatments, which did not differ between themselves (an average of 792 min/day. The steers from the wheat bran treatment remained less time feeding (184 min/day compared with those fed the other treatments, whose average time of permanence in this activity was 214 minutes per day. The other studied variables did not present a significant difference between the treatments. Inclusion of wheat bran in the diet of the confined steers results in less spent time idle, while steers feeding on soybean hulls spend less time feeding. The use of corn, soybean hulls, or wheat bran in the diet of the confined steers does not affect the total cudding time.

  5. Aplanatic grazing incidence diffraction grating: a new optical element

    International Nuclear Information System (INIS)

    Hettrick, M.C.

    1986-01-01

    We present the theory of a grazing incidence reflection grating capable of imaging at submicron resolution. The optic is mechanically ruled on a spherical or cylindrical surface with varied groove spacings, delivering diffraction-limited response and a wide field of view at a selected wavelength. Geometrical aberrations are calculated on the basis of Fermat's principle, revealing significant improvements over a grazing incidence mirror. Aplanatic and quasi-aplanatic versions of the grating have applications in both imaging and scanning microscopes, microprobes, collimators, and telescopes. A 2-D crossed system of such gratings, similar to the grazing incidence mirror geometry of Kirkpatrick and Baez, could potentially provide spatial resolutions of --200 A

  6. Beam steering for circular switched parasitic arrays using a combinational approach

    CSIR Research Space (South Africa)

    Mofolo, ROM

    2011-09-01

    Full Text Available In this paper, the authors present a method of electronic beam steering for circular switched parasitic array (SPA) antennas. In circular SPA antennas, one achieves azimuth beam steering by open-circuiting and short-circuiting different parasitic...

  7. comparative beef production from buli,s, steers and heifers under

    African Journals Online (AJOL)

    steers, although statistically significant, were much srnaller than differences obtained in the present study. Out of a maximum possible grading of 20 points, bulls obtained an average of 12,3 points (Grade I -) which is considerably lower than the grading points obtained by steers (16,3 = Prime) or by heifers (17,5 = Prime+).

  8. Poultry performance in different grazing densities: forage characteristics, losses due to grazing and feed intake

    Directory of Open Access Journals (Sweden)

    Luciano Cristiano França

    2014-02-01

    Full Text Available Morphological characteristics of three forage species grazed by rustic poultry in stocking were evaluated. Coast-cross fodder, kikuyu grass, and stylosanthes were planted in 33-m2 paddocks with two densities (m2/animal: D1 = 3m2/animal and D2 = 1m2/animal. The design was a randomized complete block with a 3 x 2 factorial (three grasses and two densities and three replications. Grass canopy height, grass mass, morphological composition (leaf, stem, and dead material, losses due to grazing, poultry weight gain and consumption, and concentrate feed conversion ratio and efficiency were evaluated. At the end of the experiment, forage and leaves masses were considered low to stylosanthes in D2 (0.28 to 0.03 kg/m2 and to kikuyu grass in D1 (0.13 to 0.05 kg/m2 and in D2 (0.11 and 0.03 kg/m2, respectively. In addition, the grass canopy height was considered low for stylosanthes (6.50 cm that could jeopardize the entry of new poultry lot. The three grass species had similar weight gain and revealed better results for 3m²/ chicken (3.20 kg/animal. Coast-cross fodder, kikuyu grass, and stylosanthes, with some exceptions, can be considered suitable for grazing fattening poultry at 3m2/animal at the evaluated time of the year (autumn.

  9. Design, Modeling And Control Of Steering And Braking For An Urban Electric Vehicle

    OpenAIRE

    Maciua, Dragos

    1996-01-01

    This report describes research which involved the design modification, modeling and control of automatic steering and braking systems for an urban electric vehicle. The vehicle is equipped with four-wheel independent drive, four-wheel independent braking and four-wheel steering. Control algorithms were developed for steering and braking. Simulation results show the feasibility of the algorithms.

  10. Avoiding Internal Capsule Stimulation With a New Eight-Channel Steering Deep Brain Stimulation Lead.

    Science.gov (United States)

    van Dijk, Kees J; Verhagen, Rens; Bour, Lo J; Heida, Ciska; Veltink, Peter H

    2017-10-15

    Novel deep brain stimulation (DBS) lead designs are currently entering the market, which are hypothesized to provide a way to steer the stimulation field away from neural populations responsible for side effects and towards populations responsible for beneficial effects. The objective of this study is to assess the performances of a new eight channel steering-DBS lead and compare this with a conventional cylindrical contact (CC) lead. The two leads were evaluated in a finite element electric field model combined with multicompartment neuron and axon models, representing the internal capsule (IC) fibers and subthalamic nucleus (STN) cells. We defined the optimal stimulation setting as the configuration that activated the highest percentage of STN cells, without activating any IC fibers. With this criterion, we compared monopolar stimulation using a single contact of the steering-DBS lead and CC lead, on three locations and four orientations of the lead. In addition, we performed a current steering test case by dividing the current over two contacts with the steering-DBS lead in its worst-case orientation. In most cases, the steering-DBS lead is able to stimulate a significantly higher percentage of STN cells compared to the CC lead using single contact stimulation or using a two contact current steering protocol when there is approximately a 1 mm displacement of the CC lead. The results also show that correct placement and orientation of the lead in the target remains an important aspect in achieving the optimal stimulation outcome. Currently, clinical trials are set up in Europe with a similar design as the steering-DBS lead. Our results illustrate the importance of the orientation of the new steering-DBS lead in avoiding side effects induced by stimulation of IC fibers. Therefore, in clinical trials sufficient attention should be paid to implanting the steering DBS-lead in the most effective orientation. © 2017 International Neuromodulation Society.

  11. Re-visiting the nutrition of dairy sheep grazing Mediterranean pastures

    Directory of Open Access Journals (Sweden)

    M. Decandia

    2010-04-01

    Full Text Available In the light of recent findings in sheep nutrition and behaviour, the diets of grazing dairy sheep should be based on forages encompassing a variety of complementary nutritional values and containing moderate levels of complementary plant secondary metabolites, until recently regarded as "anti-nutritional". In lactating sheep, pastures of tannin-containing legumes like sulla (Hedysarum coronarium and chicory (Cichorium intybus can be integrated with annual grasses for establishing sustainable artificial pastures under rainfed conditions. Diets based on these forages, while ensuring high milking performance, can mitigate the unbalance of CP to energy ratio of grazing sheep. By grazing sulla and annual or Italian ryegrass (50:50 by area as spatially conterminal monocultures or in timely sequence (complementary grazing sheep eat more and perform better than by grazing the ryegrass pasture only. Concentrate supplementation of lactating sheep should be preferably based on fibrous sources (soyhulls or beet pulps, particularly from mid-lactation onwards and when supplementation levels are high. Milk urea concentration is confirmedly a useful monitoring tool to balance protein nutrition and curb the waste of N at animal and system level.

  12. Root Characteristics of Perennial Warm-Season Grasslands Managed for Grazing and Biomass Production

    Directory of Open Access Journals (Sweden)

    Rattan Lal

    2013-07-01

    Full Text Available Minirhizotrons were used to study root growth characteristics in recently established fields dominated by perennial C4-grasses that were managed either for cattle grazing or biomass production for bioenergy in Virginia, USA. Measurements over a 13-month period showed that grazing resulted in smaller total root volumes and root diameters. Under biomass management, root volume was 40% higher (49 vs. 35 mm3 and diameters were 20% larger (0.29 vs. 0.24 mm compared to grazing. While total root length did not differ between grazed and biomass treatments, root distribution was shallower under grazed areas, with 50% of total root length in the top 7 cm of soil, compared to 41% in ungrazed exclosures. These changes (i.e., longer roots and greater root volume in the top 10 cm of soil under grazing but the reverse at 17–28 cm soil depths were likely caused by a shift in plant species composition as grazing reduced C4 grass biomass and allowed invasion of annual unsown species. The data suggest that management of perennial C4 grasslands for either grazing or biomass production can affect root growth in different ways and this, in turn, may have implications for the subsequent carbon sequestration potential of these grasslands.

  13. Energy partition for maintenance and weight gain in Nellore and crossbred steers finished under grazing Partição de energia para mantença e ganho em novilhos nelores e mestiços terminados a pasto

    Directory of Open Access Journals (Sweden)

    N.F. Sant´Ana

    2011-04-01

    Full Text Available The objective of this work was to estimate net energy (NEm and metabolizable energy (MEm requirements for maintenance and efficiency of use of metabolizable energy for maintanence (k m and gain (k g of grazing Nellore and crossbred steers. It was used 24 castrated steers, 12 Nellore breed (386 kg SBW and 12 ½ Limousin-Nelore crossbred (397 kg SBW. The comparative slaughter method was used. In each genetic group, animals were grouped in three similar groups: reference; restrict feeding and ad libitum feeding. The reference group was slaughtered in the beginning of the experiment whereas the others were slaughtered at the end of it. During the 104 days of the experimental period, the group under restrict feeding had access to pastures for 3.5 hours daily whereas the group with ad libitum feeding remained on pasture full time. Forage intake was estimated in two trials by using the double-indicator method. Values of NEm, MEm, k m and k g were estimated on the basis of empty body weight (EBW through linear and non-linear model fitting. Requirements of NEm and MEm did not differ among Nellore and crossbred animals. In the linear model, the following results were obtained: Requirements of NEm = 86 kcal/kg0.75; requirements of MEm = 136 kcal/kg0.75 and k m = 0.63. Kg value was higher for Nellore animals (0.39 than for crossbred animals (k g = 0.33. Requirement of net energy of maintenance does not differ among grazing Nellores and ½ European-Nellore crossbred. For the same body weight, Nellore animals present greater fat proportion in gain composition than ½European-Nelore crossbred.Este trabalho foi conduzido com o objetivo de estimar as exigências de energia líquida (ELm e metabolizável (EMm para mantença e as eficiências de utilização da energia metabolizável para mantença (k m e ganho (k g de novilhos nelores e mestiços a pasto. Foram utilizados 24 novilhos castrados, sendo 12 da raça Nelore (386 kg PCJ e 12 mestiços ½ Limousin

  14. Genetic algorithm–based varying parameter linear quadratic regulator control for four-wheel independent steering vehicle

    Directory of Open Access Journals (Sweden)

    Linlin Gao

    2015-11-01

    Full Text Available From the perspective of vehicle dynamics, the four-wheel independent steering vehicle dynamics stability control method is studied, and a four-wheel independent steering varying parameter linear quadratic regulator control system is proposed with the help of expert control method. In the article, a four-wheel independent steering linear quadratic regulator controller for model following purpose is designed first. Then, by analyzing the four-wheel independent steering vehicle dynamic characteristics and the influence of linear quadratic regulator control parameters on control performance, a linear quadratic regulator control parameter adjustment strategy based on vehicle steering state is proposed to achieve the adaptive adjustment of linear quadratic regulator control parameters. In addition, to further improve the control performance, the proposed varying parameter linear quadratic regulator control system is optimized by genetic algorithm. Finally, simulation studies have been conducted by applying the proposed control system to the 8-degree-of-freedom four-wheel independent steering vehicle dynamics model. The simulation results indicate that the proposed control system has better performance and robustness and can effectively improve the stability and steering safety of the four-wheel independent steering vehicle.

  15. Optimising stocking rate and grazing management to enhance environmental and production outcomes for native temperate grasslands

    Science.gov (United States)

    Badgery, Warwick; Zhang, Yingjun; Huang, Ding; Broadfoot, Kim; Kemp, David; Mitchell, David

    2015-04-01

    Stocking rate and grazing management can be altered to enhance the sustainable production of grasslands but the relative influence of each has not often been determined for native temperate grasslands. Grazing management can range from seasonal rests through to intensive rotational grazing involving >30 paddocks. In large scale grazing, it can be difficult to segregate the influence of grazing pressure from the timing of utilisation. Moreover, relative grazing pressure can change between years as seasonal conditions influence grassland production compared to the relative constant requirements of animals. This paper reports on two studies in temperate native grasslands of northern China and south eastern Australia that examined stocking rate and regionally relevant grazing management strategies. In China, the grazing experiment involved combinations of a rest, moderate or heavy grazing pressure of sheep in spring, then moderate or heavy grazing in summer and autumn. Moderate grazing pressure at 50% of the current district average, resulted in the better balance between maintaining productive and diverse grasslands, a profitable livestock system, and mitigation of greenhouse gases through increased soil carbon, methane uptake by the soil, and efficient methane emissions per unit of weight gain. Spring rests best maintained a desirable grassland composition, but had few other benefits and reduced livestock productivity due to lower feed quality from grazing later in the season. In Australia, the grazing experiment compared continuous grazing to flexible 4- and 20-paddock rotational grazing systems with sheep. Stocking rates were adjusted between systems biannually based on the average herbage mass of the grassland. No treatment degraded the perennial pasture composition, but ground cover was maintained at higher levels in the 20-paddock system even though this treatment had a higher stocking rate. Overall there was little difference in livestock production (e.g. kg

  16. Effects of slow-release urea on ruminal digesta characteristics and growth performance in beef steers

    DEFF Research Database (Denmark)

    Taylor-Edwards, C C; Hibbard, G; Kitts, S E

    2009-01-01

    Two experiments were conducted to evaluate the effects of slow urea (SRU) versus feed-grade urea on ruminal metabolite characteristics in steers and DMI, gain, and G:F in growing beef steers.......Two experiments were conducted to evaluate the effects of slow urea (SRU) versus feed-grade urea on ruminal metabolite characteristics in steers and DMI, gain, and G:F in growing beef steers....

  17. Auditory orientation in crickets: Pattern recognition controls reactive steering

    Science.gov (United States)

    Poulet, James F. A.; Hedwig, Berthold

    2005-10-01

    Many groups of insects are specialists in exploiting sensory cues to locate food resources or conspecifics. To achieve orientation, bees and ants analyze the polarization pattern of the sky, male moths orient along the females' odor plume, and cicadas, grasshoppers, and crickets use acoustic signals to locate singing conspecifics. In comparison with olfactory and visual orientation, where learning is involved, auditory processing underlying orientation in insects appears to be more hardwired and genetically determined. In each of these examples, however, orientation requires a recognition process identifying the crucial sensory pattern to interact with a localization process directing the animal's locomotor activity. Here, we characterize this interaction. Using a sensitive trackball system, we show that, during cricket auditory behavior, the recognition process that is tuned toward the species-specific song pattern controls the amplitude of auditory evoked steering responses. Females perform small reactive steering movements toward any sound patterns. Hearing the male's calling song increases the gain of auditory steering within 2-5 s, and the animals even steer toward nonattractive sound patterns inserted into the speciesspecific pattern. This gain control mechanism in the auditory-to-motor pathway allows crickets to pursue species-specific sound patterns temporarily corrupted by environmental factors and may reflect the organization of recognition and localization networks in insects. localization | phonotaxis

  18. Prescribed grazing for management of invasive vegetation in a hardwood forest understory

    Science.gov (United States)

    Ronald A. Rathfon; Songlin Fei; Jason Tower; Kenneth Andries; Michael. Neary

    2014-01-01

    Land managers considering prescribed grazing (PG) face a lack of information on animal stocking rates, timing of grazing, and duration of grazing to achieve desired conditions in natural ecosystems under invasion stress from a variety of nonnative invasive plant (NNIP) species. In this study we tested PG treatments using goats for reducing NNIP brush species and...

  19. Grassland Fire and Cattle Grazing Regulate Reptile and Amphibian Assembly Among Patches

    Science.gov (United States)

    Larson, Danelle M.

    2014-12-01

    Fire and grazing are common management schemes of grasslands globally and are potential drivers of reptilian and amphibian (herpetofauna) metacommunity dynamics. Few studies have assessed the impacts of fire and cattle grazing on herpetofauna assemblages in grasslands. A patch-burn grazing study at Osage Prairie, MO, USA in 2011-2012 created landscape patches with treatments of grazing, fire, and such legacies. Response variables were measured before and after the application of treatments, and I used robust-design occupancy modeling to estimate patch occupancy and detection rate within patches, and recolonization and extinction (i.e., dispersal) across patches. I conducted redundancy analysis and a permuted multivariate analysis of variance to determine if patch type and the associated environmental factors explained herpetofauna assemblage. Estimates for reptiles indicate that occupancy was seasonally constant in Control patches ( ψ ~ 0.5), but declined to ψ ~ 0.15 in patches following the applications of fire and grazing. Local extinctions for reptiles were higher in patches with fire or light grazing ( ɛ ~ 0.7) compared to the controls. For the riparian herpetofaunal community, patch type and grass height were important predictors of abundance; further, the turtles, lizards, snakes, and adult amphibians used different patch types. The aquatic amphibian community was predicted by watershed and in-stream characteristics, irrespective of fire or grazing. The varying responses from taxonomic groups demonstrate habitat partitioning across multiple patch types undergoing fire, cattle grazing, and legacy effects. Prairies will need an array of patch types to accommodate multiple herpetofauna species.

  20. 46 CFR 185.320 - Steering gear, controls, and communication system tests.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering gear, controls, and communication system tests. 185.320 Section 185.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS) OPERATIONS Miscellaneous Operating Requirements § 185.320 Steering...

  1. Resilience of soils and vegetation subjected to different grazing ...

    African Journals Online (AJOL)

    The resilience of rangeland soils and vegetation to different levels of grazing is still poorly understood. A study was conducted to determine the recovery of a rangeland grazed at different intensities and allowed a two-year rest period. The following treatments were applied to 0.5 hectare plots: 0, 4, 8 and 16 heifers per ...

  2. Seasonality constraints to livestock grazing intensity.

    Science.gov (United States)

    Fetzel, Tamara; Havlik, Petr; Herrero, Mario; Erb, Karl-Heinz

    2017-04-01

    Increasing food production is essential to meet the future food demand of a growing world population. In light of pressing sustainability challenges such as climate change and the importance of the global livestock system for food security as well as GHG emissions, finding ways to increasing food production sustainably and without increasing competition for food crops is essential. Yet, many unknowns relate to livestock grazing, in particular grazing intensity, an essential variable to assess the sustainability of livestock systems. Here, we explore ecological limits to grazing intensity (GI; i.e. the fraction of net primary production consumed by grazing animals) by analysing the role of seasonality in natural grasslands. We estimate seasonal limitations to GI by combining monthly net primary production data and a map of global livestock distribution with assumptions on the length of nonfavourable periods that can be bridged by livestock (e.g. by browsing dead standing biomass, storage systems or biomass conservation). This allows us to derive a seasonality-limited potential GI, which we compare with the GI prevailing in 2000. We find that GI in 2000 lies below its potential on 39% of the total global natural grasslands, which has a potential for increasing biomass extraction of up to 181 MtC/yr. In contrast, on 61% of the area GI exceeds the potential, made possible by management. Mobilizing this potential could increase milk production by 5%, meat production by 4% or contribute to free up to 2.8 Mio km² of grassland area at the global scale if the numerous socio-ecological constraints can be overcome. We discuss socio-ecological trade-offs, which may reduce the estimated potential considerably and require the establishment of sound monitoring systems and an improved understanding of livestock system's role in the Earth system. © 2017 John Wiley & Sons Ltd.

  3. Parâmetros ruminais e desaparecimento da MS, PB e FDN da forragem em bovinos suplementados em pastagem na estação seca Ruminal parameters and DM, CP and NDF forage disappearance of supplemented steers under grazing, during the dry season

    Directory of Open Access Journals (Sweden)

    Ana Vera Martins Franco

    2004-10-01

    Full Text Available O trabalho foi conduzido com o objetivo de determinar o efeito de suplementos concentrados com diferentes degradabilidades da proteína (alta-70%, média-50% e baixa-30% e o efeito da quantidade dos mesmos (0,5, 1,0 e 1,5 kg de MS/dia sobre os parâmetros ruminais (pH e N-NH3 e o desaparecimento da MS, PB e FDN da forragem em bovinos pastejando Brachiaria brizantha cv. Marandu no período da seca. Foram utilizados 10 novilhos canulados no rúmen com peso médio de 354 kg em um esquema fatorial com três repetições (blocos. Não houve influência da degradabilidade protéica e/ou quantidade de suplemento sobre os valores de pH ruminal, que variaram de 6,38 a 6,91. As concentrações de N-NH3 ruminal foram crescentes com o aumento da degradabilidade do suplemento e quantidade de suplementação, sendo maiores uma hora após o fornecimento do suplemento e decrescendo até cinco horas. O tratamento-controle apresentou concentrações de N-NH3 consideradas adequadas para boa atividade microbiana. Não houve efeito da degradabilidade protéica do suplemento ou quantidade na degradação ruminal da MS, PB e da FDN da forragem, não diferindo do tratamento-controle. Quanto aos parâmetros de degradação ruminal da forrageira, os valores médios foram de 29% para a fração solúvel da PB e de de 47% para a insolúvel potencialmente degradável, com taxa de degradação de 4,88%. Para FDN, a fração potencialmente degradável foi de 56% e a taxa de degradação, de 4,33%.The objective this work was to evaluate the effect of protein supplements with three degradability levels (high-70%, medium-50% and low-30% at three levels (0.5, 1.0 and 1.5 kg/day on the ruminal pH, N-NH3 and DM, CP, NDF degradability of forage fed steers grazing Brachiaria brizantha cv. Maradu, during the dry season. The experiment design was a randomized complete block with three replications (grazing periods and the supplement treatments were arranged in a factorial 3x3. Ten

  4. Chromium supplementation enhances the acute phase response of steers to a lipopolysaccharide (LPS) challenge

    Science.gov (United States)

    The study examined the effect of chromium supplementation on the response of steers to an LPS challenge. Twenty crossbred steers (235±4 kg BW) received 0 ppb (Control; C) or 200 ppb chromium propionate (CHR) for 55 days. Steers were fitted with jugular catheters and rectal temperature (RT) recording...

  5. Effect of Grazing Behavior on Weight Regain Post-Bariatric Surgery: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Nathalia Pizato

    2017-12-01

    Full Text Available Grazing, a type of maladaptive eating behavior, has been associated with poor weight outcomes in bariatric patients. The purpose of this study was to conduct a systematic review of the association between grazing behavior and weight regain post-bariatric surgery. Literature searches, study selection, design of the method, and quality appraisal were carried out by two independent authors. The search strategy was performed until October 2017 in Medline, Embase, Cochrane, Lilacs, Scopus, Web of Science, Google Scholar, ProQuest Dissertation & Theses, and Open Grey. Of a total of 3764 articles, five papers met the inclusion criteria (four original articles and one thesis, comprising 994 subjects, mostly women. The prevalence of grazing behavior ranged from 16.6 to 46.6%, and the highest prevalence of significant weight regain was 47%. The association between grazing and weight regain was observed in four of the five evaluated studies. Our findings support an association between grazing behavior and weight regain after bariatric surgery, regardless of surgery type and contextual concept of grazing. Further studies are needed to confirm the clarity of the real prevalence and interfering factors related to grazing behavior and weight outcomes.

  6. Tree-shrub associations in grazed woodlands: First rodents, then cattle?

    NARCIS (Netherlands)

    Smit, C.; Verwijmeren, M.

    2011-01-01

    Spatial associations of tree saplings with spiny or toxic plants in grazed woodlands are generally explained by associational resistance, i. e., protection against grazing via a well-defended neighbor. In this study, we tested whether directed seed dispersal and post-dispersal seed removal by wood

  7. The evaluation of four Eragrostis curvula ecotypes with grazing sheep.

    African Journals Online (AJOL)

    There were no significant differences in the dry matter production and chemical composition of the clipped samples of the ecotypes. Keywords: afrikaans; chemical composition; dry matter production; ecotypes; eragrostis curvula; grazing; live mass; live mass gains; open rotational grazing system; production; sheep; south ...

  8. Morphological Responses Explain Tolerance of the Bamboo Yushania microphylla to Grazing

    Directory of Open Access Journals (Sweden)

    Kesang Wangchuk

    2014-01-01

    Full Text Available Mechanisms of tolerance of the bamboo Y. microphylla to ungulate herbivory were investigated by measuring above- and belowground morphogenetic traits and biomass allocation patterns of the bamboo Y. microphylla under grazed and ungrazed conditions in a Himalayan mixed conifer forest. Data were collected from 5 populations consisting of 10 ramets each in adjacent grazed and ungrazed plots. Compared with ungrazed ramets, the aboveground morphological modifications of grazed ramets were higher culm density, shorter and thinner culms, shorter internode, and shorter top leaf. The belowground morphological modifications for the grazed ramets were thinner rhizomes, lower rhizome biomass and dry matter, more nodes, and shorter internodes. Despite the lower biomass and dry matter, the root-to-shoot ratio was higher for grazed ramets. Results suggest that Y. microphylla subjected to herbivory shows aboveground overcompensation in terms of densification at the cost of belowground biomass, but at the same time maintains a higher proportion of belowground reserves, as compared to ungrazed conditions. These responses provide adequate evidence to conclude that Y. microphylla tolerates ungulate herbivory through above- and belowground morphological modifications.

  9. Patterns in Greater Sage-grouse population dynamics correspond with public grazing records at broad scales.

    Science.gov (United States)

    Monroe, Adrian P; Aldridge, Cameron L; Assal, Timothy J; Veblen, Kari E; Pyke, David A; Casazza, Michael L

    2017-06-01

    Human land use, such as livestock grazing, can have profound yet varied effects on wildlife interacting within common ecosystems, yet our understanding of land-use effects is often generalized from short-term, local studies that may not correspond with trends at broader scales. Here we used public land records to characterize livestock grazing across Wyoming, USA, and we used Greater Sage-grouse (Centrocercus urophasianus) as a model organism to evaluate responses to livestock management. With annual counts of male Sage-grouse from 743 leks (breeding display sites) during 2004-2014, we modeled population trends in response to grazing level (represented by a relative grazing index) and timing across a gradient in vegetation productivity as measured by the Normalized Vegetation Difference Index (NDVI). We found grazing can have both positive and negative effects on Sage-grouse populations depending on the timing and level of grazing. Sage-grouse populations responded positively to higher grazing levels after peak vegetation productivity, but populations declined when similar grazing levels occurred earlier, likely reflecting the sensitivity of cool-season grasses to grazing during peak growth periods. We also found support for the hypothesis that effects of grazing management vary with local vegetation productivity. These results illustrate the importance of broad-scale analyses by revealing patterns in Sage-grouse population trends that may not be inferred from studies at finer scales, and could inform sustainable grazing management in these ecosystems. © 2017 by the Ecological Society of America.

  10. Throughput-Based Traffic Steering in LTE-Advanced HetNet Deployments

    DEFF Research Database (Denmark)

    Gimenez, Lucas Chavarria; Kovacs, Istvan Z.; Wigard, Jeroen

    2015-01-01

    The objective of this paper is to propose traffic steering solutions that aim at optimizing the end-user throughput. Two different implementations of an active mode throughput-based traffic steering algorithm for Heterogeneous Networks (HetNet) are introduced. One that always forces handover of t...... throughput is generally higher, reaching values of 36% and 18% for the medium- and high-load conditions....

  11. On Using Current Steering Logic in Mixed Analogue-digital Circuits

    DEFF Research Database (Denmark)

    Lehmann, Torsten

    1998-01-01

    The authors investigate power supply noise in mixed analogue-digital circuits, arising from communication between the analogue and digital parts of the circuit. Current steering techniques and proper buffering are used to show which noise currents can be reduced and which cannot. In addition......, a high-swing current steering buffer for driving analogue switches or external digital signals is proposed....

  12. Conditional steering under the von Neumann scenario

    Science.gov (United States)

    Mukherjee, Kaushiki; Paul, Biswajit; Karmakar, Sumana; Sarkar, Debasis; Mukherjee, Amit; Bhattacharya, Some Sankar; Roy, Arup

    2017-08-01

    In Phys. Lett. A 166, 293 (1992), 10.1016/0375-9601(92)90711-T, Popescu and Rohrlich characterized nonlocality of pure n -partite entangled systems by studying bipartite violation of local realism when n -2 number of parties perform projective measurements on their particles. A pertinent question in this scenario is whether similar characterization is possible for n -partite mixed entangled states also. In the present work we have followed an analogous approach so as to explore whether given a tripartite mixed entangled state the conditional bipartite states obtained by performing projective measurement on the third party demonstrate a weaker form of nonlocality, quantum steering. We also compare this phenomenon of conditional steering with existing notions of tripartite correlations.

  13. Vegetation patterns and nutrients in relation to grazing pressure and ...

    African Journals Online (AJOL)

    A major challenge confronting managers of extensive grazing systems is uneven use of erbaceous forage plants by livestock. The concentration of grazing in preferred areas or around foci points (e.g. water points) eventually results in adverse impacts in soil nutrients, vegetation structure, production and composition.

  14. 46 CFR 122.320 - Steering gear, controls, and communication system tests.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Steering gear, controls, and communication system tests... communication system tests. The master of a vessel shall have examined and tested the steering gear, signaling whistle, propulsion controls, and communication systems of the vessel prior to getting underway for a...

  15. Suplementação infrequente e fontes proteicas para recria de bovinos em pastejo no período seco: parâmetros nutricionais Infrequent supplementation and protein sources for growing steers grazing in the dry season: nutritional parameters

    Directory of Open Access Journals (Sweden)

    N.F. Paula

    2011-04-01

    Full Text Available Objetivou-se com este estudo avaliar os efeitos de fontes proteicas e da frequência de fornecimento de suplemento sobre o consumo e a digestibilidade dos nutrientes, as concentrações de nitrogênio amoniacal (N-NH3, o pH ruminal e o nitrogênio ureico no soro de bovinos recriados em pastagem de Brachiaria brizantha cv. Marandu no período seco. Foram utilizados cinco novilhos mestiços Nelore × Angus fistulados no rúmen, castrados, com peso médio inicial de 295 kg em um delineamento quadrado latino 5 × 5. Avaliaram-se dois suplementos isoproteicos, um com farelo de soja (FS e outro com farelo de algodão de alta energia, fornecidos em duas frequências: diariamente (7 vezes por semana e 3 vezes por semana (segundas, quartas e sextas-feiras; e mistura mineral (MM. A suplementação aumentou o consumo de PB, extrato etéreo (EE e carboidratos não-fibrosos (CNF, em kg/dia. O suplemento com farelo de algodão o consumo de extrato etéreo. Houve efeito positivo da suplementação 3 vezes por semana sobre os consumos de matéria seca total, de forragem, de matéria orgânica de forragem, carboidratos totais (CT e FDN. A suplementação reduziu a digestibilidade da FDN e aumentou a de PB. O suplemento com farelo de algodão reduziu a digestibilidade de FDN e carboidratos totais. A suplementação 3 vezes por semana não afetou a digestibilidade dos nutrientes nem o pH ruminal. O consumo de suplemento aumenta as concentrações de N-NH3, principalmente se realizado 3 vezes por semana. As concentrações de nitrogênio ureico no soro de bovinos em pastejo aumentam com o consumo de suplementos.The objective of this study was to evaluate the effects of protein sources and frequency of supplement offer on the intake and nutrient digestibility, on the concentrations of ammonia nitrogen (N-NH3, on rumen pH and on serum urea nitrogen concentrations in steers grazing pasture of Brachiaria brizantha cv. Marandu during the dry season. Five crossbred Zebu

  16. Phytoplankton growth and microzooplankton grazing in the subtropical Northeast Atlantic.

    Directory of Open Access Journals (Sweden)

    Carlos Cáceres

    Full Text Available Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E. Our design included two phytoplankton size fractions (0.2-5 µm and >5 µm and five depths, allowing us to characterize differences in growth and grazing rates between size fractions and depths, as well as to estimate vertically integrated measurements. Phytoplankton growth rates were high (0.11-1.60 d(-1, especially in the case of the large fraction. Grazing rates were also high (0.15-1.29 d(-1, suggesting high turnover rates within the phytoplankton community. The integrated balances between phytoplankton growth and grazing losses were close to zero, although deviations were detected at several depths. Also, O2 supersaturation was observed up to 110 m depth during both Lagrangian surveys. These results add up to increased evidence indicating an autotrophic metabolic balance in oceanic subtropical gyres.

  17. Phytoplankton Growth and Microzooplankton Grazing in the Subtropical Northeast Atlantic

    Science.gov (United States)

    Cáceres, Carlos; Taboada, Fernando González; Höfer, Juan; Anadón, Ricardo

    2013-01-01

    Dilution experiments were performed to estimate phytoplankton growth and microzooplankton grazing rates during two Lagrangian surveys in inner and eastern locations of the Eastern North Atlantic Subtropical Gyre province (NAST-E). Our design included two phytoplankton size fractions (0.2–5 µm and >5 µm) and five depths, allowing us to characterize differences in growth and grazing rates between size fractions and depths, as well as to estimate vertically integrated measurements. Phytoplankton growth rates were high (0.11–1.60 d−1), especially in the case of the large fraction. Grazing rates were also high (0.15–1.29 d−1), suggesting high turnover rates within the phytoplankton community. The integrated balances between phytoplankton growth and grazing losses were close to zero, although deviations were detected at several depths. Also, O2 supersaturation was observed up to 110 m depth during both Lagrangian surveys. These results add up to increased evidence indicating an autotrophic metabolic balance in oceanic subtropical gyres. PMID:23935946

  18. Effects of previous grazing nutrition and management on feedlot performance of cattle.

    Science.gov (United States)

    Drouillard, J S; Kuhl, G L

    1999-01-01

    Management strategies designed to improve grazing animal performance can influence feedlot performance and carcass traits both positively and negatively. In spite of the economic relevance of potential interactions between grazing and finishing performance, controlled experiments evaluating integrated production systems are limited in number. Effects of grazing treatments can result from, or be overshadowed by, changes in gut fill, thus making it difficult to assign precise costs to different phases of production. Published reports have considered the effects of stocking rate, duration of grazing, forage characteristics, supplementation, and growth-promoting implants on subsequent finishing performance. Improvements in cattle performance attributed to changes in stocking rate generally have been neutral to positive with respect to effects on finishing performance. Comparisons among forages have led to the suggestion that forage species may contribute to differences in gastrointestinal fill of grazing cattle, thereby influencing gain and efficiency during the subsequent finishing phase. Creep-feeding suckling calves generally has increased preweaning performance but has had relatively little influence on performance during the subsequent finishing phase. Grain supplementation of stocker cattle during the grazing period has improved grazing performance, but effects on subsequent feedlot performance have been inconsistent. Potential carryover effects from protein and mineral supplementation also have been inconclusive. Lack of congruence among studies is puzzling but may be the consequence of highly varied production systems, differences in experimental procedures, and changes in gut fill or mass of internal organs. Based on the studies reviewed, the expression or absence of compensatory growth during the finishing phase appears to be related to the nutritional quality of forages utilized in the grazing period, with higher quality forages tending to yield greater

  19. Steering disturbance rejection using a physics-based neuromusculoskeletal driver model

    Science.gov (United States)

    Mehrabi, Naser; Sharif Razavian, Reza; McPhee, John

    2015-10-01

    The aim of this work is to develop a comprehensive yet practical driver model to be used in studying driver-vehicle interactions. Drivers interact with their vehicle and the road through the steering wheel. This interaction forms a closed-loop coupled human-machine system, which influences the driver's steering feel and control performance. A hierarchical approach is proposed here to capture the complexity of the driver's neuromuscular dynamics and the central nervous system in the coordination of the driver's upper extremity activities, especially in the presence of external disturbance. The proposed motor control framework has three layers: the first (or the path planning) plans a desired vehicle trajectory and the required steering angles to perform the desired trajectory; the second (or the musculoskeletal controller) actuates the musculoskeletal arm to rotate the steering wheel accordingly; and the final layer ensures the precision control and disturbance rejection of the motor control units. The physics-based driver model presented here can also provide insights into vehicle control in relaxed and tensed driving conditions, which are simulated by adjusting the driver model parameters such as cognition delay and muscle co-contraction dynamics.

  20. Effects of clay on fat necrosis and carcass characteristics in Japanese Black steers.

    Science.gov (United States)

    Oka, Akio; Iwamoto, Eiji; Tatsuda, Ken

    2015-10-01

    Twenty 10-month-old Japanese Black steers were used to evaluate the effects of clay on fat necrosis and carcass characteristics. Ten steers (Clay group) were fed the clay (50 g/day) during 10-30 months of age. The other 10 steers (Control group) were not fed it. There was no significant difference in body weight or average daily gain between the two groups (P > 0.05). The occurrence of fat necrotic mass in the Clay group (30%) was lower (P Clay group was smaller (P clay prevented the occurrence of fat necrosis and did not affect the carcass characteristics in Japanese Black steers. © 2015 Japanese Society of Animal Science.

  1. X-ray grazing incidence diffraction from multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Tixier, S.; Boeni, P.; Swygenhoven, H. van; Horisberger, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Grazing incidence scattering geometries using synchrotron radiation have been applied in order to characterise the roughness profiles and the structural coherence of multilayers. The lateral correlation length of the roughness profiles was evaluated using diffuse reflectivity in the `out of plane` geometry. This type of measurement is the only diffuse reflectivity technique allowing large lateral momentum transfer. It is typically suitable for correlation lengths smaller than 1000 A. The lateral structural coherence length of Ni{sub 3}Al/Ni multilayers as a function of the layer thickness was obtained by grazing incidence diffraction (GID). 3 figs., 1 ref.

  2. Slow-release urea in supplement fed to beef steers

    Directory of Open Access Journals (Sweden)

    Ana Paula Gonçalves

    2015-02-01

    Full Text Available Replacing regular urea (RU by slow-release urea (SRU at two levels of non-protein nitrogen (NPN in concentrate, offered with low-quality roughage, was evaluated in beef steers on dry matter intake (DMI, ruminal fermentation parameters, plasma urea nitrogen (PUN, total tract apparent digestibility of diets and in situ degradability of nitrogen sources. Eight ruminally cannulated steers were allocated into two 4x4 Latin squares, totalizing four treatments: 40 NPN/0 SRU: 40% of concentrate crude protein (CP as NPN, resulting from 0% of SRU and 100% of RU; 40 NPN/50 SRU: 40% of concentrate CP as NPN, resulting from 50% of SRU and 50% of RU; 40 NPN/100 SRU: 40% of concentrate CP as NPN, resulting from 100% of SRU and 0% of RU; 80 NPN/100 SRU: 80% of concentrate CP as NPN, resulting from 100% of SRU and 0% of RU. Results showed that partial substitution of regular urea by slow-release urea did not alter dry matter intake, pattern of ruminal fermentation or plasma urea nitrogen concentrations and increased the total tract apparent digestibility of crude protein in steers diets. The increase in non-protein nitrogen content in crude protein of the concentrate could compromise feed intake and the efficiency of nutrient utilization in the steers fed complete diets based on low quality forage.

  3. Possibilities and constraints for grazing in high output dairy systems

    NARCIS (Netherlands)

    Hennessy, D.; Delaby, L.; Pol, van den A.; Shalloo, L.

    2015-01-01

    In temperate and oceanic regions, grazed grass is the lowest cost feed available for milk production. In other regions, grazed grass is less important but can contribute to the diet of livestock. Within high output systems the interaction between the animal and sward is challenging for a host of

  4. Effect of mowing and grazing on ramet emergence of Leymus ...

    African Journals Online (AJOL)

    user

    2011-03-21

    Mar 21, 2011 ... experiment was conducted in the spring of 2004 to investigate the effects on the surface soil temperature caused by mowing, grazing and grazing exclusion, and the influence of these factors on the ramets emergence characteristics. The primary effect of the treatments was significant changes in.

  5. Static load simulation of steering knuckle for a formula student race car

    Science.gov (United States)

    Saputro, Bagus Aulia; Ubaidillah, Triono, Dicky Agus; Pratama, Dzaky Roja; Cahyono, Sukmaji Indro; Imaduddin, Fitrian

    2018-02-01

    This research aims to determine the stress distribution which occurs on the steering knuckle and to define its safety factor number. Steering knuckle is the most critical part of a car's steering system. Steering knuckle supports the tie rod, brake caliper, and the wheels to provide stability. Steering knuckle withstands the load which given on the front wheels and functions as the wheel's axis. Balljoint and king support the rotation of the suspension arm. When the car is in idle position, knuckle hold the weight of the car, it gets braking force when it's braking and cornering. Knuckle is designed to have the strength that could withstand load and to have a good safety factor value. Knuckle is designed using Fusion software then simulated using Fusion simulation software with a static load, moment braking force, and cornering force as the loads in this simulation. The simulation works in ideal condition. The result of this simulation is satisfying. This simulation produces a maximum displacement of 0.01281mm, the maximum shear stress is 3.707 MPa on the stub hole, and the safety factor is 5.24. The material used for this product is mild steel AISI 1018.

  6. Non-Mechanical Beam Steering in Free-Space Optical Communication Transceivers

    Science.gov (United States)

    Shortt, Kevin

    Free-space optical communications systems are a rapidly growing field as they carry many of the advantages of traditional fibre-based communications systems without the added investment of installing complex infrastructure. Moreover, these systems are finding key niches in mobile platforms in order to take advantage of the increased bandwidth over traditional RF systems. Of course, the inevitable problem of tracking arises when dealing with mobile stations. To compound the problem in the case of communications to low Earth or geosynchronous orbits, FSOC systems typically operate with tightly confined beams over great distances often requiring pointing accuracies on the order of micro-radians or smaller. Mechanisms such as gimbal mounts and fine-steering mirrors are the usual candidates for platform stabilization, however, these clearly have substantial power requirements and inflate the mass of the system. Spatial light modulators (also known as optical phased arrays), on the other hand, offer a suitable alternative for beam-pointing stabilization. Some of the advantages of spatial light modulators over fine-steering mirrors include programmable multiple simultaneous beams, dynamic focus/defocus and moderate to excellent optical power handling capability. This thesis serves as an investigation into the implementation of spatial light modulators as a replacement for traditional fine-steering mirrors in the fine-pointing subsystem. In particular, pointing accuracy and scanning ability will be highlighted as performance metrics in the context of a variety of communication scenarios. Keywords: Free-space optical communications, beam steering, fine-steering mirror, spatial light modulator, optical phased array.

  7. Herbage availability €rs a stress factor on grazed Coastcross II ...

    African Journals Online (AJOL)

    ) relationships for Coastcross ll Bermuda grass grazed for four consecutive summer periods by young growing beef cattle. Stocking rate affected the daily. LWG/animal through its influence on herbage availability. Rota- tional grazing showed a ...

  8. Beam steered millimeter-wave fiber-wireless system for 5G indoor coverage

    NARCIS (Netherlands)

    Cao, Z.; Wang, Q.; Tessema, N.M.; Leijtens, X.J.M.; Soares, F.M.; Koonen, A.M.J.

    2016-01-01

    A 38GHz beam steered fiber-wireless system, enabled by a novel integrated optical tunable delay line, is demonstrated for 5G indoor coverage. The beam steering gains 14dBm spatial power focusing and 6 times EVM improvement.

  9. Particle-assisted wetting

    International Nuclear Information System (INIS)

    Xu Hui; Yan Feng; Tierno, Pietro; Marczewski, Dawid; Goedel, Werner A

    2005-01-01

    Wetting of a solid surface by a liquid is dramatically impeded if either the solid or the liquid is decorated by particles. Here it is shown that in the case of contact between two liquids the opposite effect may occur; mixtures of a hydrophobic liquid and suitable particles form wetting layers on a water surface though the liquid alone is non-wetting. In these wetting layers, the particles adsorb to, and partially penetrate through, the liquid/air and/or the liquid/water interface. This formation of wetting layers can be explained by the reduction in total interfacial energy due to the replacement of part of the fluid/fluid interfaces by the particles. It is most prominent if the contact angles at the fluid/fluid/particle contact lines are close to 90 0

  10. Plasma protein loss associated with gastrointestinal parasitism in grazing sheep.

    Science.gov (United States)

    Yakoob, A Y; Holmes, P H; Parkins, J J; Armour, J

    1983-01-01

    Some pathophysiological effects of parasitic gastroenteritis in two groups of lambs grazing paddocks either heavily or lightly contaminated with trichostrongyle larvae were investigated between July and October 1980. The leak of plasma protein was measured on three occasions at pasture using 51chromic chloride. Total faecal output was measured indirectly using chromic oxide. Losses of 51chromic chloride-labelled plasma protein into the gastrointestinal tract were significantly higher in the lambs grazing the heavily contaminated pasture than in those grazing lightly infected ground in both July and August. The increased plasma losses were associated with high faecal egg counts, hypoalbuminaemia and elevated levels of plasma pepsinogen.

  11. Adjustable Grazing-Incidence X-Ray Optics

    Science.gov (United States)

    O'Dell, Stephen L.; Reid, Paul B.

    2015-01-01

    With its unique subarcsecond imaging performance, NASA's Chandra X-ray Observatory illustrates the importance of fine angular resolution for x-ray astronomy. Indeed, the future of x-ray astronomy relies upon x-ray telescopes with comparable angular resolution but larger aperture areas. Combined with the special requirements of nested grazing-incidence optics, mass, and envelope constraints of space-borne telescopes render such advances technologically and programmatically challenging. The goal of this technology research is to enable the cost-effective fabrication of large-area, lightweight grazing-incidence x-ray optics with subarcsecond resolution. Toward this end, the project is developing active x-ray optics using slumped-glass mirrors with thin-film piezoelectric arrays for correction of intrinsic or mount-induced distortions.

  12. Development of a Computational Steering Framework for High Performance Computing Environments on Blue Gene/P Systems

    KAUST Repository

    Danani, Bob K.

    2012-07-01

    Computational steering has revolutionized the traditional workflow in high performance computing (HPC) applications. The standard workflow that consists of preparation of an application’s input, running of a simulation, and visualization of simulation results in a post-processing step is now transformed into a real-time interactive workflow that significantly reduces development and testing time. Computational steering provides the capability to direct or re-direct the progress of a simulation application at run-time. It allows modification of application-defined control parameters at run-time using various user-steering applications. In this project, we propose a computational steering framework for HPC environments that provides an innovative solution and easy-to-use platform, which allows users to connect and interact with running application(s) in real-time. This framework uses RealityGrid as the underlying steering library and adds several enhancements to the library to enable steering support for Blue Gene systems. Included in the scope of this project is the development of a scalable and efficient steering relay server that supports many-to-many connectivity between multiple steered applications and multiple steering clients. Steered applications can range from intermediate simulation and physical modeling applications to complex computational fluid dynamics (CFD) applications or advanced visualization applications. The Blue Gene supercomputer presents special challenges for remote access because the compute nodes reside on private networks. This thesis presents an implemented solution and demonstrates it on representative applications. Thorough implementation details and application enablement steps are also presented in this thesis to encourage direct usage of this framework.

  13. Mixed farming in a grazing reserve in Northern Nigeria | Babalobi ...

    African Journals Online (AJOL)

    Nigeria's main pastoral development strategy is the settlement of pastoralists in grazing reserves. The goal of the strategy is to turn such nomadic pastoralists into mixed farmers who will take up crop farming to supplement livestock farming. Using the Bobi Grazing Reserve, Niger State, Nigeria as case study, the attainment ...

  14. Transformation of a savanna grassland by drought and grazing | O ...

    African Journals Online (AJOL)

    The relative effects of drought and heavy grazing on the floristic composition, population size and and structure, and basal cover of an African savanna grassland were differentiated by comparing changes over eight years over eight years, which included a severe drought year, across a gradient of grazing history. Drought ...

  15. Dairy farmers using mob grazing in Pennsylvania and New York

    Science.gov (United States)

    Proponents of ultra-high stocking density grazing emphasize increased forage use efficiency and soil improvement by grazing mature forage with stocking densities up to 500,000 lb per acre of beef cattle on small paddocks with rest periods up to 180 days. However, it is unclear if this management tec...

  16. The grazing index method of range condition assessment | du Toit ...

    African Journals Online (AJOL)

    Owing to the difficulty of examining succession theory in the Karoo, it is suggested the ecological index method (EIM), be replaced by the grazing index method (GIM), through the introduction of grazing index values (GIV) for Karoo plant species. The GIM may provide more acceptable range condition scores and more ...

  17. Forage selection and performance of sheep grazing dry annual range.

    NARCIS (Netherlands)

    Ridder, de N.; Benjamin, R.W.; Keulen, van H.

    1986-01-01

    During 114 days of grazing, sheep grazing a dry annual pasture in Israel selected the fine fraction available with a higher nutritive value. As this fraction became depleted and feed quality dropped, organic matter intake dropped from 1.73 to 0.75 kg/sheep/d. Sheep lost weight, body condition and

  18. Grasses grazed by springbok and sheep | R. | African Journal of ...

    African Journals Online (AJOL)

    Grazing habits were determined by analysis of rumina from slaughtered springbok and sheep where springbok grazed together with Merino sheep in False Upper Karoo and together with Dorper sheep in Kalahari Thornveld. Results show that in both veld types, grass constituted about 39 percent of the dry mass intake of ...

  19. Optimization of steering elements in the RIA driver linac

    International Nuclear Information System (INIS)

    Lessner, E. S.; Aseev, V. S.; Ostroumov, P. N.; Physics

    2005-01-01

    The driver linac of the projected RIA facility is a versatile accelerator, a 1.4-GV, CW superconducting (SC) linac designed to simultaneously accelerate several heavy-ion charge states, providing beams from proton to uranium at 400 MeV/u at power levels at a minimum of 100 kW and up to 400 kW for most beams. Acceleration of multiple-charge-state uranium beams places stringent requirements on the linac design. A steering algorithm was derived that fulfilled the driver's real estate requirements, such as placement of steering dipole coils on SC solenoids and of beam position monitors outside cryostats, and beam-dynamics requirements, such as coupling effects induced by the focusing solenoids. The algorithm has been fully integrated into the tracking code TRACK and it is used to study and optimize the number and position of steering elements that minimize the multiple-beam centroid oscillations and preserve the beam emittance under misalignments of accelerating and transverse focusing elements in the driver linac

  20. Effect of grazing on the cow welfare of dairy herds evaluated by a multidimensional welfare index

    DEFF Research Database (Denmark)

    Burow, E.; Rousing, T.; Thomsen, P. T.

    2013-01-01

    Structural development in the prime sector has led to increasing herd sizes and new barn systems, followed by less summer grazing for dairy cows in Denmark. Effects of grazing on single welfare measures in dairy cows - for example, the presence of integument alterations or mortality - have been......) inspired multidimensional dairy cow welfare assessment protocol, the within-herd effect of summer grazing compared with winter barn housing in Danish dairy herds with cubicle free-stall systems for the lactating cows. Our hypothesis was that cow welfare in dairy herds was better during summer grazing than...... out to be more beneficial than few daily grazing hours (range average above 9 to 21 h) for the welfare of the dairy herds. In conclusion, this study reports a positive within-herd effect of summer grazing on dairy cow welfare, where many daily grazing hours were more beneficial than few daily grazing...

  1. Steering, Entanglement, Nonlocality, and the EPR Paradox

    Science.gov (United States)

    Wiseman, Howard; Jones, Steve; Andrew, Doherty

    2007-06-01

    The concept of steering was introduced by Schroedinger in 1935 as a generalization of the EPR paradox for arbitrary pure bipartite entangled states and arbitrary measurements by one party. Until now, it has never been rigorously defined, so it has not been known (for example) what mixed states are steerable (that is, can be used to exhibit steering). We provide an operational definition, from which we prove (by considering Werner states and Isotropic states) that steerable states are a strict subset of the entangled states, and a strict superset of the states that can exhibit Bell-nonlocality. For arbitrary bipartite Gaussian states we derive a linear matrix inequality that decides the question of steerability via Gaussian measurements, and we relate this to the original EPR paradox.

  2. Towards evenly distributed grazing patterns: including social context in sheep management strategies

    Directory of Open Access Journals (Sweden)

    Agustina di Virgilio

    2016-06-01

    Full Text Available Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals’ foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals’ space use patterns, our aim was to explore the potential effects of including animals’ social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock grazing on three different paddocks (with sizes from 80 to 1000 Ha during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets, age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females used more intensively the most preferred areas and low-ranked (i.e., yearlings used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour. Discussion. Although homogenization and segregation of

  3. Towards evenly distributed grazing patterns: including social context in sheep management strategies.

    Science.gov (United States)

    di Virgilio, Agustina; Morales, Juan Manuel

    2016-01-01

    Background. A large proportion of natural grasslands around the world is exposed to overgrazing resulting in land degradation and biodiversity loss. Although there is an increasing effort in the promotion of sustainable livestock management, rangeland degradation still occurs because animals' foraging behaviour is highly selective at different spatial scales. The assessment of the ecological mechanisms modulating the spatial distribution of grazing and how to control it has critical implications for long term conservation of resources and the sustainability of livestock production. Considering the relevance of social interactions on animals' space use patterns, our aim was to explore the potential effects of including animals' social context into management strategies using domestic sheep grazing in rangelands as case study. Methods. We used GPS data from 19 Merino sheep (approximately 10% of the flock) grazing on three different paddocks (with sizes from 80 to 1000 Ha) during a year, to estimate resource selection functions of sheep grazing in flocks of different levels of heterogeneity. We assessed the effects of sheep class (i.e., ewes, wethers, and hoggets), age, body condition and time since release on habitat selection patterns. Results. We found that social rank was reflected on sheep habitat use, where dominant individuals (i.e., reproductive females) used more intensively the most preferred areas and low-ranked (i.e., yearlings) used less preferred areas. Our results showed that when sheep grazed on more heterogeneous flocks, grazing patterns were more evenly distributed at all the paddocks considered in this study. On the other hand, when high-ranked individuals were removed from the flock, low-ranked sheep shifted their selection patterns by increasing the use of the most preferred areas and strongly avoided to use less preferred sites (i.e., a highly selective grazing behaviour). Discussion. Although homogenization and segregation of flocks by classes

  4. SPS Beam Steering for LHC Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Gianfelice-Wendt, Eliana [Fermilab; Bartosik, Hannes [CERN; Cornelis, Karel [CERN; Norderhaug Drøsdal, Lene [CERN; Goddard, Brennan [CERN; Kain, Verena [CERN; Meddahi, Malika [CERN; Papaphilippou, Yannis [CERN; Wenninger, Jorg [CERN

    2014-07-01

    The CERN Super Proton Synchrotron accelerates beams for the Large Hadron Collider to 450 GeV. In addition it produces beams for fixed target facilities which adds complexity to the SPS operation. During the run 2012-2013 drifts of the extracted beam trajectories have been observed and lengthy optimizations in the transfer lines were performed to reduce particle losses in the LHC. The observed trajectory drifts are consistent with the measured SPS orbit drifts at extraction. While extensive studies are going on to understand, and possibly suppress, the source of such SPS orbit drifts the feasibility of an automatic beam steering towards a “golden” orbit at the extraction septa, by means of the interlocked correctors, is also being investigated. The challenges and constraints related to the implementation of such a correction in the SPS are described. Simulation results are presented and a possible operational steering strategy is proposed.

  5. Pointing Device Performance in Steering Tasks.

    Science.gov (United States)

    Senanayake, Ransalu; Goonetilleke, Ravindra S

    2016-06-01

    Use of touch-screen-based interactions is growing rapidly. Hence, knowing the maneuvering efficacy of touch screens relative to other pointing devices is of great importance in the context of graphical user interfaces. Movement time, accuracy, and user preferences of four pointing device settings were evaluated on a computer with 14 participants aged 20.1 ± 3.13 years. It was found that, depending on the difficulty of the task, the optimal settings differ for ballistic and visual control tasks. With a touch screen, resting the arm increased movement time for steering tasks. When both performance and comfort are considered, whether to use a mouse or a touch screen for person-computer interaction depends on the steering difficulty. Hence, a input device should be chosen based on the application, and should be optimized to match the graphical user interface. © The Author(s) 2016.

  6. Calculation of the beam injector steering system using Helmholtz coils

    International Nuclear Information System (INIS)

    Passaro, A.; Sircilli Neto, F.; Migliano, A.C.C.

    1991-03-01

    In this work, a preliminary evaluation of the beam injector steering system of the IEAv electron linac is presented. From the existing injector configuration and with the assumptions of monoenergetic beam (100 keV) and uniform magnetic field, two pairs of Helmholtz coils were calculated for the steering system. Excitations of 105 A.turn and 37 A.turn were determined for the first and second coils, respectively. (author)

  7. Using NDVI to estimate carbon fluxes from small rotationally grazed pastures

    Science.gov (United States)

    Satellite-based Normalized Difference Vegetation Index (NDVI) data have been extensively used for estimating gross primary productivity (GPP) and yield of grazing lands throughout the world. However, the usefulness of satellite-based images for monitoring rotationally-grazed pastures in the northea...

  8. Does grazing management matter for soil carbon sequestration in shortgrass steppe?

    Science.gov (United States)

    Considerable uncertainty remains regarding the potential of grazing management on semiarid rangelands to sequester soil carbon. Short-term (less than 1 decade) studies have determined that grazing management potentially influences fluxes of carbon, but such studies are strongly influenced by prevail...

  9. A Vehicle Haptic Steering by Wire System Based on High Gain GPI Observers

    Directory of Open Access Journals (Sweden)

    A. Rodriguez-Angeles

    2014-01-01

    Full Text Available A vehicle steering by wire (SBW haptic system based on high gain generalized proportional integral (GPI observers is introduced. The observers are considered for the estimation of dynamic perturbations that are present at the tire and steering wheel. To ensure efficient tracking between the commanded steering wheel angle and the tire orientation angle, the estimated perturbations are on line canceled. As to provide a haptic interface with the driver, the estimated dynamic effects at the steering rack are fed back to the steering wheel, yielding a master-slave haptic system with bilateral communication. For implementation purposes few sensors and minimum knowledge of the dynamic model are required, which is a major advantage compared to other approaches. Only position tracking errors are fed back, while all other signals are estimated by the high gain GPI observers. The scheme is robust to uncertainty on the input gain and cancels dynamic perturbation effects such as friction and aligning forces on the tire. Experimental results are presented on a prototype platform.

  10. Arbitrary vehicle steering characteristics with changing ratio rack and pinion transmission

    Directory of Open Access Journals (Sweden)

    András G Bendefy

    2015-12-01

    Full Text Available In order to achieve arbitrary steering characteristics at vehicles, a steering mechanism was developed, in which changing ratio rack and pinion connections have been applied. In contrary to a regular steering mechanism where only a single rack is used, two racks were applied in order to make arbitrary characteristics possible. The turning wheel’s required motion functions had to be defined first, thereafter could we determine the changing ratio rack and pinion geometry which produces this motion. First, a simplified two-dimensional mockup was created in order to study the difficulties and possibilities of a real construction. Later, a fully functional assembly was designed and manufactured to make further experiments possible.

  11. Fundamentals studies of a magnetically steered vacuum arc

    Science.gov (United States)

    Walke, Paul

    In recent years demand from production industry for high performance cutting tools, aero and automobile engine parts has prompted research into both existing and novel methods of laying down hard, low friction coatings . A key process for the production of such coatings has been Physical Vapour Deposition (PVD) which has proved to be a consistent and reliable tool for industry. For this technique to continue to be improved and more advanced coatings to be produced, research at the fundamental level is required. This thesis describes research investigating the behaviour of the steered arc cathode spot and methods of improving existing steered arc coating technology.The majority of existing steered arc systems use either permanent magnets or a combination of permanent and electromagnets to steer the arc. Described here is a novel system which employs a pair of electromagnetic coils of cylindrical geometry which enable the arc to be positioned on a circular orbit through a range of continuously variable radii. In addition to this the coils are capable of controlling the transverse and normal magnetic field profiles independently of the steering radius selected. This enables the behaviour of the arc spot to be investigated under a range of magnetic field conditions thus allowing the comparison of measured arc behaviour with a new model of arc motion. Care has described the motion of the arc spot as a biased random walk and has derived an analytical solution to describe the time dependent, probability density function for the arc position in two dimensions. Two distributions are proposed (one in each dimension); the first describes the probability density for the arc position in the direction of driven motion, the second the probability density in the direction of arc confinement. The shape of these distributions is dependent upon the transverse and normal components of the applied magnetic field.A series of experiments are described here that measure the shape of these

  12. 1000 years of sustainable grazing in Nordic conditions?

    DEFF Research Database (Denmark)

    Brandt, Jesper

    landscapes at different spatial levels. Information on much of this sort of regulation has however been lost through modern times, tended to prefer modern (nature) scientific methods primarily developed as general (meaning not spatially contextual) recommendations for raising productivity. During the later...... years this modern tradition has also been preferred by investigations to find solutions for non-sustainable types of land use in grazing systems. However, much sustainability-relevant wisdom has been accumulated in historical grazing-systems that should be included in the repertoire of knowledge...

  13. Tillering dynamics in pastures of guinea grass subjected to grazing severities under intermittent stocking

    Directory of Open Access Journals (Sweden)

    Denise Baptaglin Montagner

    2012-03-01

    Full Text Available This experiment was carried out to analyze the tillering dynamics of the species Panicum maximum cv. Mombaca subjected to three post-grazing heights: residue of 30 cm (30; residue of 50 cm (50; and residue of 50 cm during spring and summer, lowered to 40 cm in the first fall season grazing and to 30 cm in the following grazing cycle, resuming to 50 cm after the first grazing of the following spring season (50-30. Grazings were initiated whenever the swards intercepted 95% of the incident light. The post-grazing heights were allocated in the experimental units in a completely randomized block design with three replications. The density of basal tillers did not vary between the residual heights evaluated. Swards managed with variable residual height (50-30 presented higher rates of appearance and mortality of basal tillers during the summer of 2007, indicating high tiller renovation. Regardless of the post-grazing height evaluated, lower rates of appearance of basal tillers were found in the spring of 2006. The stability index of guinea grass cv. Mombaca was close to 1.0 throughout the experimental period. Swards managed with variable post-grazing present structural changes able to improve the regrowth vigor, which may be important to maximize the use of the forage species in the production system.

  14. ABB wet flue gas desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Niijhawan, P.

    1994-12-31

    The wet limestone process for flue gas desulfurization (FGD) is outlined. The following topics are discussed: wet flue gas desulfurization, wet FGD characteristics, wet scrubbers, ABB wet FGD experience, wet FGD forced oxidation, advanced limestone FGD systems, key design elements, open spray tower design, spray tower vs. packed tower, important performance parameters, SO{sub 2} removal efficiency, influence by L/G, limestone utilization, wet FGD commercial database, particulate removal efficiencies, materials of construction, nozzle layout, spray nozzles, recycle pumps, mist elimination, horizontal flow demister, mist eliminator washing, reagent preparation system, spray tower FGDS power consumption, flue gas reheat options, byproduct conditioning system, and wet limestone system.

  15. Desempenho de novilhos mantidos em pastagens de capim-elefante e capim-mombaça Performance of steers raised on pastures of Elephant and Mombasa grasses

    Directory of Open Access Journals (Sweden)

    Carolina de Souza Garcia

    2011-02-01

    massa corporal foi de 850 g/dia e o ganho por área de 246 kg/ha durante o período experimental.The performance of steers raised on elephant and mombasa grass pastures was evaluated from October to December 2006. A rotational grazing system with a regulated forage offer was adopted. The experimental area consisted of two repetitions containing 18 0.25-ha paddocks divided into nine paddocks with elephant grass and nine with mombasa grass. Forage species, area repetition, the interaction among these effects, paddocks within the interaction, and the experimental error were the effects of the treatments. This model was used to analyze pasture attributes. For analyses of intake, digestibility and gain, 24 steers were randomly assigned to the respective interactions among forage vs. repetition vs. grazing system, totaling three animals per triple interaction. The grazing systems consisted of ad libitum (AL and restricted (PR grazing. Elephant-grass showed the highest total dry matter biomass (TB and green leaf dry matter biomass (GLDM. There were no differences among forage plants for production of biomass of green leaf dry matter; leaf proportion was the greatest in mombasa grass, however. Extrusas showed similar bromatological composition. Only crude protein intake, which was the highest for mombasa pasture, differed among forage plants. Ad libitum feeding enabled a higher intake of all nutrients from both pastures. Digestibility of nutrients was higher for elephant-grass but it did not differ among feeding levels: only crude protein content was the highest on pasture where grazing was restrict and gross energy content of pasture was higher for ad libitum grazing system. Despite qualitative and quantitative differences among forage plants, differences of weight gain per animal and per area were not found. For animal with ad libitum feeding, average body mass gain was 850 g/day and gain per area was 246 kg/ha during the experimental period.

  16. Geometrodynamic steering principle reveals the determiners of inertia

    International Nuclear Information System (INIS)

    Wheeler, J.A.

    1988-01-01

    What shall the authors need to grasp the essence of quantum gravity? One requirement, at least, is essential: to understand the steering principle of classical geometrodynamics. The authors outline here the physical content of that steering principle - heat of the so-called initial value problem - in its J.W. York, Jr. formulation. The central idea epitomizes itself in a single simple sentence: Mass-energy there determines inertia here. They spell out this steering principle both in its precise form and in its poor man's version. At both levels of analysis considerations of physics and mathematics alike require that the effective mass-energy of gravity waves must make itself felt on the spacetime geometry - and therefore on the gyro-defined local inertial frame of reference - on the same level as matter itself. Additional to the (mass)/(distance) Newtonian potential so familiar as measure of the effect of a nearby mass on the local frame is the Thirring and Lense gravitomagnetic potential, proportional to (angular momentum) x (distance vector)/(distance). The recent proposal of Ciufolini for a dual laser-ranged LAGEOS satellite to detect the thus-predicted gravitomagnetism of the earth is briefly described

  17. Effects of livestock grazing on grasshopper abundance on a native rangeland in Montana.

    Science.gov (United States)

    O'Neill, Kevin M; Olson, Bret E; Wallander, Roseann; Rolston, Marni G; Seibert, Catherine E

    2010-06-01

    Livestock grazing can affect habitat quality for grasshoppers through effects on food and oviposition site availability, microclimate, and other factors. Because of this, some authors have suggested that grazing programs can be used to help manage pest grasshopper populations. In a 6-yr study, we controlled access of cattle to replicated experimental plots on an Agropyron spicatum/Poa sandbergii pasture to create consistent year-to-year differences in postgrazing plant cover, with resultant affects on microclimate. After sampling grasshoppers multiple times after grazing treatments each summer, we found evidence of between-treatment differences in grasshopper abundance for the entire assemblage during 4 of the 6 yr. Some species, including Melanoplus sanguinipes (perhaps the worse rangeland grasshopper pest in the western United States), tended to be more abundant on ungrazed plots, whereas Melanoplus gladstoni often had greater densities on heavily-grazed plots. The effect of grazing on grasshopper densities in this study was lower in magnitude and less consistent among years than in a study we conducted simultaneously at a nearby site where the vegetation was dominated by the exotic species crested wheatgrass (Agropyron cristatum). Our results generally support proposals that grazing could be used to reduce pest grasshopper densities, although the effectiveness of a particular grazing scheme may vary among sites, years, and grasshopper and vegetation assemblages.

  18. [Community structure and diversity of soil arthropods in naturally restored sandy grasslands after grazing].

    Science.gov (United States)

    Liu, Ren-tao; Zhao, Ha-lin; Zhao, Xue-yong

    2010-11-01

    Taking the Naiman Desertification Research Station under Chinese Academy of Sciences as a base, an investigation was conducted on the community structure of soil arthropods in the naturally restored sandy grasslands after different intensity grazing disturbance, with the effects of vegetation and soil on this community structure approached. In the non-grazing grassland, soil arthropods were rich in species and more in individuals, and had the highest diversity. In the restored grassland after light grazing, soil arthropods had the lowest evenness and diversity. In the restored grassland after moderate grazing, the individuals of soil arthropods were lesser but the major groups were more, and the evenness and diversity were higher. In the restored grassland after heavy grazing, the individuals of soil arthropods were more but the major groups were lesser, and the diversity was higher. Plant individuals' number, vegetation height and coverage, and soil alkalinity were the main factors affecting the soil arthropod community in naturally restored grasslands after different intensity grazing disturbance. It was implied that after 12-year exclosure of grassland, soil arthropod community could be recovered to some degree, while grazing disturbance had long-term negative effects on the arthropod community.

  19. Milk from cows grazing on cool-season pastures provides an enhanced profile of bioactive fatty acids compared to those grazed on a monoculture of pearl millet.

    Science.gov (United States)

    Bainbridge, Melissa L; Egolf, Emily; Barlow, John W; Alvez, Juan P; Roman, Joe; Kraft, Jana

    2017-02-15

    The demand for dairy products from grass-fed cows is driven, in part, by their more desirable fatty acid (FA) profile, containing more n-3 FA and conjugated linoleic acids (CLA) than conventionally produced dairy products. This study investigated the effects of pearl millet (PM) vs. cool-season pasture (CSP) on animal performance and milk FA in a grazing system. Eight Holstein dairy cows were used in a repeated measures design with four-week periods. Forage type had no effect on animal performance (estimated dry matter intake, milk production, fat, or protein). The contents of CLA and n-3 FA in a serving of whole milk (3.25% fat) increased when cows grazed CSP compared to PM. A serving of whole milk from cows grazing PM had a higher content of saturated FA and branched-chain FA. In conclusion, the contents of various bioactive FA were higher in milk fat of cows grazing a CSP compared to PM. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Packaging consideration of two-dimensional polymer-based photonic crystals for laser beam steering

    Science.gov (United States)

    Dou, Xinyuan; Chen, Xiaonan; Chen, Maggie Yihong; Wang, Alan Xiaolong; Jiang, Wei; Chen, Ray T.

    2009-02-01

    In this paper, we report the theoretical study of polymer-based photonic crystals for laser beam steering which is based on the superprism effect as well as the experiment fabrication of the two dimensional photonic crystals for the laser beam steering. Superprism effect, the principle for beam steering, was separately studied in details through EFC (Equifrequency Contour) analysis. Polymer based photonic crystals were fabricated through double exposure holographic interference method using SU8-2007. The experiment results were also reported.

  1. A hybrid system for beam steering and wavefront control

    Science.gov (United States)

    Nikulin, Vladimir V.

    2004-06-01

    Performance of long-range mobile laser systems operating within Earth's atmosphere is generally limited by several factors. Movement of the communicating platforms, such as aircraft, terrain vehicles, etc., complemented by mechanical vibrations, is the main cause of pointing errors. In addition, atmospheric turbulence causes changes of the refractive index along the propagation path that lead to phase distortions (aberrations), thus creating random redistribution of optical energy in the spatial domain. The combined effect of these factors leads to an increased bit-error probability under adverse operation conditions. While traditional approaches provide separate treatment of these problems, suggesting the development of high-bandwidth beam steering systems to perform tracking and jitter rejection, and wavefront control for the mitigation of atmospheric effects, the two tasks could be integrated. In this paper we present a hybrid laser beam steering/wavefront control system comprising an electrically addressed spatial light modulator (SLM) installed on the Omni-Wrist sensor mount platform. The function of the Omni-Wrist is to provide coarse steering over a wide range of pointing angles, while the purpose of the SLM is twofold: it performs wavefront correction and fine steering. The control law for the Omni-Wrist is synthesized using the decentralized approach that provides independent access to the azimuth and declination channels, while the algorithm for calculating the required phase profile for the SLM is optimization-based. This paper presents the control algorithms, the approach to coordinating the operation of the both systems and the simulation results.

  2. Holistic Management: Misinformation on the Science of Grazed Ecosystems

    Directory of Open Access Journals (Sweden)

    John Carter

    2014-01-01

    Full Text Available Over 3 billion hectares of lands worldwide are grazed by livestock, with a majority suffering degradation in ecological condition. Losses in plant productivity, biodiversity of plant and animal communities, and carbon storage are occurring as a result of livestock grazing. Holistic management (HM has been proposed as a means of restoring degraded deserts and grasslands and reversing climate change. The fundamental approach of this system is based on frequently rotating livestock herds to mimic native ungulates reacting to predators in order to break up biological soil crusts and trample plants and soils to promote restoration. This review could find no peer-reviewed studies that show that this management approach is superior to conventional grazing systems in outcomes. Any claims of success due to HM are likely due to the management aspects of goal setting, monitoring, and adapting to meet goals, not the ecological principles embodied in HM. Ecologically, the application of HM principles of trampling and intensive foraging are as detrimental to plants, soils, water storage, and plant productivity as are conventional grazing systems. Contrary to claims made that HM will reverse climate change, the scientific evidence is that global greenhouse gas emissions are vastly larger than the capacity of worldwide grasslands and deserts to store the carbon emitted each year.

  3. Radiobiological problems concerning grazing animals following the Chernobyl accident

    International Nuclear Information System (INIS)

    Prister, B.S.; Lazarev, N.M.; Romanov, L.M.

    1997-01-01

    Chernobyl accident took place on April 26 1986, which was the beginning of the grazing season, when there was not enough fodder on the farms and the cattle was grazed on the open territory. Therefore grazing animal-breeding was the most radioactively affected branch. The consumption of contaminated fodder and surface contamination with radioactive precipitation caused the accumulation of considerable ingested doses in the organisms of animals (up to 1 GY). Radioactive damage caused to the thyroid by the selective accumulation of radioiodine (mainly 131 I) is of particular attention. Cumulative doses of thyroid irradiation in mammals were much higher than for the other organs. Thus, in cows during their grazing on the contaminated pastures outside 30-km zone the ratio of ingested doses of the thyroid and whole body was 130:1 and more, therefore, radiation effects could have a certain negative effect, concerning the agricultural animals in the zone of accidental release influence. Accumulated ingested doses in the thyroid of cows on the contaminated territory in a number of cases caused the complete destruction of the thyroid (doses above 600 Gy), which provided the loss of milk productivity and reproductive qualities of the animals. Lower doses caused the functional disturbances, which in most cases have been levelled during the years after the accident

  4. The Occurrence and Toxicity of Indospicine to Grazing Animals

    Directory of Open Access Journals (Sweden)

    Mary T. Fletcher

    2015-07-01

    Full Text Available Indospicine is a non-proteinogenic amino acid which occurs in Indigofera species with widespread prevalence in grazing pastures across tropical Africa, Asia, Australia, and the Americas. It accumulates in the tissues of grazing livestock after ingestion of Indigofera. It is a competitive inhibitor of arginase and causes both liver degeneration and abortion. Indospicine hepatoxicity occurs universally across animal species but the degree varies considerably between species, with dogs being particularly sensitive. The magnitude of canine sensitivity is such that ingestion of naturally indospicine-contaminated horse and camel meat has caused secondary poisoning of dogs, raising significant industry concern. Indospicine impacts on the health and production of grazing animals per se has been less widely documented. Livestock grazing Indigofera have a chronic and cumulative exposure to this toxin, with such exposure experimentally shown to induce both hepatotoxicity and embryo-lethal effects in cattle and sheep. In extensive pasture systems, where animals are not closely monitored, the resultant toxicosis may well occur after prolonged exposure but either be undetected, or even if detected not be attributable to a particular cause. Indospicine should be considered as a possible cause of animal poor performance, particularly reduced weight gain or reproductive losses, in pastures where Indigofera are prevalent.

  5. Monitoring of livestock grazing effects on Bureau of Land Management land

    Science.gov (United States)

    Veblen, Kari E.; Pyke, David A.; Aldridge, Cameron L.; Casazza, Michael L.; Assal, Timothy J.; Farinha, Melissa A.

    2013-01-01

    Public land management agencies, such as the Bureau of Land Management (BLM), are charged with managing rangelands throughout the western United States for multiple uses, such as livestock grazing and conservation of sensitive species and their habitats. Monitoring of condition and trends of these rangelands, particularly with respect to effects of livestock grazing, provides critical information for effective management of these multiuse landscapes. We therefore investigated the availability of livestock grazing-related quantitative monitoring data and qualitative region-specific Land Health Standards (LHS) data across BLM grazing allotments in the western United States. We then queried university and federal rangeland science experts about how best to prioritize rangeland monitoring activities. We found that the most commonly available monitoring data were permittee-reported livestock numbers and season-of-use data (71% of allotments) followed by repeat photo points (58%), estimates of forage utilization (52%), and, finally, quantitative vegetation measurements (37%). Of the 57% of allotments in which LHS had been evaluated as of 2007, the BLM indicated 15% had failed to meet LHS due to livestock grazing. A full complement of all types of monitoring data, however, existed for only 27% of those 15%. Our data inspections, as well as conversations with rangeland experts, indicated a need for greater emphasis on collection of grazing-related monitoring data, particularly ground cover. Prioritization of where monitoring activities should be focused, along with creation of regional monitoring teams, may help improve monitoring. Overall, increased emphasis on monitoring of BLM rangelands will require commitment at multiple institutional levels.

  6. Impact of processing on in vitro digestion of milk from grazing organic and confined conventional herds

    Science.gov (United States)

    Debate on differences between milk from grazing and non-grazing cows has not addressed the effects that standard processing may have on milk digestibility. In this study, raw milk from grazing organic (ORG) and non-grazing conventional (CONV) herds was adjusted to 0 and 3.25% fat and processed as fo...

  7. Regional livestock grazing, human demography and fire incidence in the Portuguese landscape

    Directory of Open Access Journals (Sweden)

    Filipa Torres-Manso

    2014-04-01

    Full Text Available Aim of study:Wildfire incidence in Portugal is high in comparison with other Mediterranean Europe countries. Wildfire problems have been worsened by complex interactions between land use, livestock grazing and human population during the 20th century. In this study we try to understand these interactions and relationships.Area of study: Portugal country. Material and Methods: For the mainland Portuguese territory we present a statistical temporal analysis (1930-2001 based on the densities of livestock grazing and human inhabitants at the smallest administrative unit level, the parish. We compare these data with fire incidence descriptors (average area burned and average fire density between 1990 and 2007. Research highlights: We have identified clusters of parishes sharing common trends in the evolution of livestock and human inhabitant densities. A cause-effect relationship was not detected between livestock grazing density and fire incidence. However, the results point out clusters of parishes where conflicts between forest, fire and livestock grazing are important in the North, Centre and South regions of Portugal.Key Words: Livestock grazing; inhabitants; forest; fire; vegetation.

  8. Dairy cows increase ingestive mastication and reduce ruminative chewing when grazing chicory and plantain.

    Science.gov (United States)

    Gregorini, P; Minnee, E M K; Griffiths, W; Lee, J M

    2013-01-01

    Although the nutritive value of chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.) has been thoroughly studied, little is known about the grazing behavior of cattle feeding on chicory and plantain swards. The objective of the present study was to assess and describe the grazing behavior of dairy cows as affected by dietary proportions of chicory and plantain fed as monocultures for part of the day. Ninety Holstein-Friesian cows (489±42 kg of body weight; 4.1±0.3 body condition score, and 216±15 d in milk) were randomly assigned to 15 groups (6 cows per group) and grazed according to 7 treatments: control (CTL, 3 groups), perennial ryegrass (Lolium perenne L.) dominant sward (24-h pasture strip); 3 chicory treatments comprising 20, 40, and 60% of the diet, strip-grazing a monoculture of chicory to a fixed postgrazing residual before strip-grazing a perennial ryegrass dominant sward (2 groups of cows per treatment); and 3 plantain treatments comprising 20, 40, and 60% of the diet, strip-grazing a monoculture of plantain to a fixed postgrazing residual before strip-grazing a perennial ryegrass dominant sward (2 groups of cows per treatment). Four focal animals per group were equipped with 3-dimensional motion sensors, which provided the number of steps taken at each minute of the day. These cows were also fitted with automatic jaw-movement recorders that identified bites, mastication during ingestion, chewing during rumination, and determined grazing, rumination and idling times and bouts. Daily grazing time and bouts were not affected by treatments but rumination time differed and was reduced by up to 90 min when cows were allocated to chicory and plantain as 60% of their diet. Ruminative chewing was reduced in cows grazing chicory and plantain by up to 20% in cows allocated to the 60% treatments. Compared with perennial ryegrass, as the dietary proportion of chicory and plantain increased, cows spent more time idling and less time ruminating

  9. Contrasting responses of insect communities to grazing intensity in lowland heathlands

    NARCIS (Netherlands)

    Wallis de Vries, Michiel; Noordijk, Jinze; Colijn, Ed O.; Smit, John T.; Veling, Kars

    2016-01-01

    Grazing at low stocking rates is often recommended for the preservation of the characteristic biodiversity of open landscapes. However, the fine-tuning of grazing management still lacks a good evidence base. This is particularly true for insect communities, as available evidence indicates that

  10. Comparison of techniques for estimating herbage intake by grazing dairy cows

    NARCIS (Netherlands)

    Smit, H.J.; Taweel, H.Z.; Tas, B.M.; Tamminga, S.; Elgersma, A.

    2005-01-01

    For estimating herbage intake during grazing, the traditional sward cutting technique was compared in grazing experiments in 2002 and 2003 with the recently developed n-alkanes technique and with the net energy method. The first method estimates herbage intake by the difference between the herbage

  11. Acoustic monitoring system to quantify ingestive behavior of free-grazing cattle

    Science.gov (United States)

    Methods to estimate intake in grazing livestock include using markers, visual observation, mechanical sensors that respond to jaw movement and acoustic recording. In most of the acoustic monitoring studies, the microphone is inverted on the forehead of the grazing livestock and the skull is utilize...

  12. Enhancement of the acute phase response to lipopolysaccharide (LPS) challenge in steers supplemented with chromium

    Science.gov (United States)

    The study examined the effect of chromium supplementation on the response of steers to an LPS challenge. Twenty steers received a premix that added 0 (control) or 0.2 mg/kg of chromium (KemTRACE®brandChromiumProprionate 0.04%, Kemin Industries) to the total diet on a dry matter basis for 55 d. Steer...

  13. Grazing intensity on the plant diversity of alpine meadow in the eastern Tibetan plateau

    Directory of Open Access Journals (Sweden)

    Wu Ning

    2004-04-01

    Full Text Available Because ofthe remoteness and harsh conditions of the high-altitude rangelands on the eastern Tibetan Plateau, the relationship between yak grazing and plant diversity has not been so clear although livestock increase was thought as the main issue leading to the degradation of rangeland. In the debate of rangeland degradation, biodiversity loss has been assumed as one of the indicators in the last two decades. In this paper authors measured the effects of different grazing intensities on the plant diversity and the structure of Kobresia pygmaea community in the case-study area, northwestern Sichuan. The results indicated that plant diversity of alpine meadow has different changing trends respectively with the change of grazing intensity and seasons. In June the highest plant diversity occurred in the intensively grazed (HG plots, but in July and September species biodiversity index of slightly grazed (LG plots is higher than other experimental treatments. In August the intermediate grazed (IG plots has the highest biodiversity index. Moreover, it was found that intensively grazing always leads to the increase of plant density, but meanwhile the decrease of community height, coverage and biomass. Over-grazing can change the community structure and lead to the succession from Kobresia pygmaea dominated community to Poa pratensis dominated. Analyzing results comprehensively, it can be suggested that the relationship between grazing intensity and plant diversity is not linear, i.e. diversity index is not as good as other characteristics of community structure to evaluate rangeland degradation on the high altitude situation. The change of biodiversity is so complicated that it can not be explained with the simple corresponding causality.

  14. Robust H2/H∞ Control for the Electrohydraulic Steering System of a Four-Wheel Vehicle

    Directory of Open Access Journals (Sweden)

    Min Ye

    2014-01-01

    Full Text Available To shorten the steer diameter and to improve the maneuverability flexibility of a construction vehicle, four wheels’ steering system is presented. This steering system consists of mechanical-electrical-hydraulic assemblies. Its diagram and principle are depicted in detail. Then the mathematical models are derived step by step, including the whole vehicle model and the hydraulic route model. Considering the nonlinear and time-varying uncertainty of the steering system, robust H2/H∞ controller is put forward to guarantee both the system performance and the robust stability. The H∞ norm of the sensitive function from the parameter perturbation of the hydraulic system to the yaw velocity of the vehicle is taken as the evaluating index of the robustness and the H2 norm of the transfer function from the external disturbance to the steering angle of the wheel as the index of linear quadratic Gaussian. The experimental results showed that the proposed scheme was superior to classical PID controller and can guarantee both the control performance and the robustness of the steering system.

  15. Wet steam wetness measurement in a 10 MW steam turbine

    Directory of Open Access Journals (Sweden)

    Kolovratník Michal

    2014-03-01

    Full Text Available The aim of this paper is to introduce a new design of the extinction probes developed for wet steam wetness measurement in steam turbines. This new generation of small sized extinction probes was developed at CTU in Prague. A data processing technique is presented together with yielded examples of the wetness distribution along the last blade of a 10MW steam turbine. The experimental measurement was done in cooperation with Doosan Škoda Power s.r.o.

  16. How to Steer and Lead Educational Processes in a Digital Medium Environment?

    DEFF Research Database (Denmark)

    Tække, Jesper

    This paper is about challenges to steering and leadership of educational interaction in classrooms provided by the new medium environment that comes with digital media. In the new medium environment, the old way of steering what is going on in the classroom appears not to work any more since...

  17. Introduction to wetting phenomena

    International Nuclear Information System (INIS)

    Indekeu, J.O.

    1995-01-01

    In these lectures the field of wetting phenomena is introduced from the point of view of statistical physics. The phase transition from partial to complete wetting is discussed and examples of relevant experiments in binary liquid mixtures are given. Cahn's concept of critical-point wetting is examined in detail. Finally, a connection is drawn between wetting near bulk criticality and the universality classes of surface critical phenomena. (author)

  18. Modeling the influence from ocean transport, mixing and grazing on phytoplankton diversity

    DEFF Research Database (Denmark)

    Adjou, Mohamed; Bendtsen, Jørgen; Richardson, Katherine

    2012-01-01

    Phytoplankton diversity, whether defined on the basis of functional groups or on the basis of numbers of individual species, is known to be heterogeneous throughout the global ocean. The factors regulating this diversity are generally poorly understood, although access to limiting nutrients...... in generating and maintaining diversity, we apply the model to quantify the potential role of zooplankton grazing and ocean transport for the coexistence of competing species and phytoplankton diversity. We analyze the sensitivity of phytoplankton biomass distributions to different types of grazing functional...... responses and show that preferential grazing on abundant species, for example as formulated by the Holling type III grazing function, is a key factor for maintaining species’ coexistence. Mixing and large-scale advection are shown to potentially have a significant impact on the distribution of phytoplankton...

  19. Phase control of entanglement and quantum steering in a three-mode optomechanical system

    Science.gov (United States)

    Sun, F. X.; Mao, D.; Dai, Y. T.; Ficek, Z.; He, Q. Y.; Gong, Q. H.

    2017-12-01

    The theory of phase control of coherence, entanglement and quantum steering is developed for an optomechanical system composed of a single mode cavity containing a partially transmitting dielectric membrane and driven by short laser pulses. The membrane divides the cavity into two mutually coupled optomechanical cavities resulting in an effective three-mode closed loop system, two field modes of the two cavities and a mechanical mode representing the oscillating membrane. The closed loop in the coupling creates interfering channels which depend on the relative phase of the coupling strengths of the field modes to the mechanical mode. Populations and correlations of the output modes are calculated analytically and show several interesting phase dependent effects such as reversible population transfer from one field mode to the other, creation of collective modes, and induced coherence without induced emission. We find that these effects result from perfect mutual coherence between the field modes which is preserved even if one of the modes is not populated. The inseparability criterion for the output modes is also investigated and we find that entanglement may occur only between the field modes and the mechanical mode. We show that depending on the phase, the field modes can act on the mechanical mode collectively or individually resulting, respectively, in tripartite or bipartite entanglement. In addition, we examine the phase sensitivity of quantum steering of the mechanical mode by the field modes. Deterministic phase transfer of the steering from bipartite to collective is predicted and optimum steering corresponding to perfect EPR state can be achieved. These different types of quantum steering can be distinguished experimentally by measuring the coincidence rate between two detectors adjusted to collect photons of the output cavity modes. In particular, we find that the minima of the interference pattern of the coincidence rate signal the bipartite steering

  20. Effects of livestock species and stocking density on accretion rates in grazed salt marshes

    Science.gov (United States)

    Nolte, Stefanie; Esselink, Peter; Bakker, Jan P.; Smit, Christian

    2015-01-01

    Coastal ecosystems, such as salt marshes, are threatened by accelerated sea-level rise (SLR). Salt marshes deliver valuable ecosystem services such as coastal protection and the provision of habitat for a unique flora and fauna. Whether salt marshes in the Wadden Sea area are able to survive accelerated SLR depends on sufficient deposition of sediments which add to vertical marsh accretion. Accretion rate is influenced by a number of factors, and livestock grazing was recently included. Livestock grazing is assumed to reduce accretion rates in two ways: (a) directly by increasing soil compaction through trampling, and (b) indirectly by affecting the vegetation structure, which may lower the sediment deposition. For four years, we studied the impact of two livestock species (horse and cattle) at two stocking densities (0.5 and 1.0 animal ha-1) on accretion in a large-scale grazing experiment using sedimentation plates. We found lower cumulative accretion rates in high stocking densities, probably because more animals cause more compaction and create a lower canopy. Furthermore, a trend towards lower accretion rates in horse-compared to cattle-grazed treatments was found, most likely because (1) horses are more active and thus cause more compaction, and (2) herbage intake by horses is higher than by cattle, which causes a higher biomass removal and shorter canopy. During summer periods, negative accretion rates were found. When the grazing and non-grazing seasons were separated, the impact of grazing differed among years. In summer, we only found an effect of different treatments if soil moisture (precipitation) was relatively low. In winter, a sufficiently high inundation frequency was necessary to create differences between grazing treatments. We conclude that stocking densities, and to a certain extent also livestock species, affect accretion rates in salt marshes. Both stocking densities and livestock species should thus be taken into account in management

  1. Oxide surfaces and metal/oxide interfaces studied by grazing incidence X-ray scattering

    Science.gov (United States)

    Renaud, Gilles

    Experimental determinations of the atomic structure of insulating oxide surfaces and metal/oxide interfaces are scarce, because surface science techniques are often limited by the insulating character of the substrate. Grazing incidence X-ray scattering (GIXS), which is not subject to charge effects, can provide very precise information on the atomic structure of oxide surfaces: roughness, relaxation and reconstruction. It is also well adapted to analyze the atomic structure, the registry, the misfit relaxation, elastic or plastic, the growth mode and the morphology of metal/oxide interfaces during their growth, performed in situ. GIXS also allows the analysis of thin films and buried interfaces, in a non-destructive way, yielding the epitaxial relationships, and, by variation of the grazing incidence angle, the lattice parameter relaxation along the growth direction. On semi-coherent interfaces, the existence of an ordered network of interfacial misfit dislocations can be demonstrated, its Burger's vector determined, its ordering during in situ annealing cycles followed, and sometimes even its atomic structure can be addressed. Careful analysis during growth allows the modeling of the dislocation nucleation process. This review emphasizes the new information that GIXS can bring to oxide surfaces and metal/oxide interfaces by comparison with other surface science techniques. The principles of X-ray diffraction by surfaces and interfaces are recalled, together with the advantages and properties of grazing angles. The specific experimental requirements are discussed. Recent results are presented on the determination of the atomic structure of relaxed or reconstructed oxide surfaces. A description of results obtained during the in situ growth of metal on oxide surfaces is also given, as well as investigations of thick metal films on oxide surfaces, with lattice parameter misfit relaxed by an array of dislocations. Recent work performed on oxide thin films having

  2. Field test of wake steering at an offshore wind farm

    Directory of Open Access Journals (Sweden)

    P. Fleming

    2017-05-01

    Full Text Available In this paper, a field test of wake-steering control is presented. The field test is the result of a collaboration between the National Renewable Energy Laboratory (NREL and Envision Energy, a smart energy management company and turbine manufacturer. In the campaign, an array of turbines within an operating commercial offshore wind farm in China have the normal yaw controller modified to implement wake steering according to a yaw control strategy. The strategy was designed using NREL wind farm models, including a computational fluid dynamics model, Simulator fOr Wind Farm Applications (SOWFA, for understanding wake dynamics and an engineering model, FLOw Redirection and Induction in Steady State (FLORIS, for yaw control optimization. Results indicate that, within the certainty afforded by the data, the wake-steering controller was successful in increasing power capture, by amounts similar to those predicted from the models.

  3. The impact of cattle and goats grazing on vegetation in oak stands of varying coppicing age

    Science.gov (United States)

    Papachristou, Thomas G.; Platis, Panayiotis D.

    2011-01-01

    The effects of cattle and goats grazing on oak shoot growth and herbaceous vegetation in three oak forest stands with different coppicing age (1, 4 and 7 yrs after the clear cutting) were investigated. In April 1997, an experimental area was chosen with three forest stands, which were clear cut in 1996 (CL1996), 1993 (CL1993), and 1990 (CL1990). All stands were grazed by cattle and goats after they were clear cut. In each forest stand, five 10 m × 10 m paired plots were located, which represented grazed and protected patches. Herbage biomass within protected and grazed plots was measured four times each year (spring: May-June, summer: July-August, autumn: September-October, and winter: November-December). Behavioural observations on grazing animals were conducted in the same periods. In both protected and open plots the height and basal diameter of all oak shoots on 5 preselected stumps were measured at the end of five growing periods from 1997 to 2001. All forest stands carried a similar amount of available herbage (averaged over forest stands and growing season, 2614 kg/ha). Grazing animals removed on average 1057 kg/ha throughout the growing period. Cattle mainly consumed herbage (97% of bites) while goats consumed a mixture of oak browse (41% bites), herbaceous species (34% bites), and other woody species browse (25% bites). The height, diameter and volume of oak shoots were affected by grazing. The three forest stands had similar shoot heights in the protected plots in 2001 after 5 years of grazing protection. The volume of oak shoots of the grazed plots were 146.7 cm3 for CL1996, 232.9 cm3 for CL1993, and 239.1 cm3 for CL1990 in 2001 (i.e. 5, 8, and 11 years grazing after the clear cuttings, respectively). The protected plots carried greater volumes of oak shoots, CL1996: 496.0 cm3 (few months grazing before protection), CL1993: 690.0 cm3 (4 years grazing before protection), and CL1990: 344.0 cm3 (7 years grazing before protection). In conclusion, almost

  4. Does pedalling on a recumbent bicycle influence the cyclist’s steering behaviour?

    NARCIS (Netherlands)

    Boon, K.M.; Klap, P.; Van Lanen, J.A.; Letsoin, G.J.; Jansen, A.J.

    2014-01-01

    The paper presents the answer to the question how pedalling on a specific recumbent bicycle, such as the VeloX3, influences a cyclist’s ability to steer the bicycle. The research aims to find the correlation between pedalling and the undesired steering movements it creates. To test this assumption a

  5. 36 CFR 222.3 - Issuance of grazing and livestock use permits.

    Science.gov (United States)

    2010-07-01

    ... livestock use permits. 222.3 Section 222.3 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE RANGE MANAGEMENT Grazing and Livestock Use on the National Forest System § 222.3 Issuance of grazing and livestock use permits. (a) Unless otherwise specified by the Chief, Forest Service, all...

  6. Modelling parasite transmission in a grazing system: the importance of host behaviour and immunity.

    Directory of Open Access Journals (Sweden)

    Naomi J Fox

    Full Text Available Parasitic helminths present one of the most pervasive challenges to grazing herbivores. Many macro-parasite transmission models focus on host physiological defence strategies, omitting more complex interactions between hosts and their environments. This work represents the first model that integrates both the behavioural and physiological elements of gastro-intestinal nematode transmission dynamics in a managed grazing system. A spatially explicit, individual-based, stochastic model is developed, that incorporates both the hosts' immunological responses to parasitism, and key grazing behaviours including faecal avoidance. The results demonstrate that grazing behaviour affects both the timing and intensity of parasite outbreaks, through generating spatial heterogeneity in parasite risk and nutritional resources, and changing the timing of exposure to the parasites' free-living stages. The influence of grazing behaviour varies with the host-parasite combination, dependent on the development times of different parasite species and variations in host immune response. Our outputs include the counterintuitive finding that under certain conditions perceived parasite avoidance behaviours (faecal avoidance can increase parasite risk, for certain host-parasite combinations. Through incorporating the two-way interaction between infection dynamics and grazing behaviour, the potential benefits of parasite-induced anorexia are also demonstrated. Hosts with phenotypic plasticity in grazing behaviour, that make grazing decisions dependent on current parasite burden, can reduce infection with minimal loss of intake over the grazing season. This paper explores how both host behaviours and immunity influence macro-parasite transmission in a spatially and temporally heterogeneous environment. The magnitude and timing of parasite outbreaks is influenced by host immunity and behaviour, and the interactions between them; the incorporation of both regulatory processes

  7. Active Full-Shell Grazing-Incidence Optics

    Science.gov (United States)

    Davis, Jacqueline M.; Elsner, Ronald F.; Ramsey, Brian D.; O'Dell, Stephen L.; Kolodziejczak, Jeffery; Weisskopf, Martin C.; Gubarev, Mikhail V.

    2016-01-01

    MSFC has a long history of developing full-shell grazing-incidence x-ray optics for both narrow (pointed) and wide field (surveying) applications. The concept presented in this paper shows the potential to use active optics to switch between narrow and wide-field geometries, while maintaining large effective area and high angular resolution. In addition, active optics has the potential to reduce errors due to mounting and manufacturing lightweight optics. The design presented corrects low spatial frequency error and has significantly fewer actuators than other concepts presented thus far in the field of active x-ray optics. Using a finite element model, influence functions are calculated using active components on a full-shell grazing-incidence optic. Next, the ability of the active optic to effect a change of optical prescription and to correct for errors due to manufacturing and mounting is modeled.

  8. Reaction of cocksfoot (Dactylis glomerata L. in grass-clover mixture on N fertilization and grazing

    Directory of Open Access Journals (Sweden)

    Marcela Andreata-Koren

    2009-09-01

    Full Text Available Grazing is the most common way of using a hill and mountain areas because of their specific agro-ecological conditions. Cocksfoot is a grass with high productivity and quality, and it is very good for sowing in the sward for grazing. Because of its good adaptability to different growing conditions, especially in very dry and cold areas, it is excellent in relation to some other good grasses, which can not be raised in such areas. The aim of the experiment was to determine effect of N application (0-N0 and 150 kg ha-1 year-1-N150 and rotational grazing by cattle (C and sheep (S, and their interaction on the cocksfoot sown in a mixture of smooth-stalked meadow grass (Poa pratensis L. and white clover (Trifolium repens L. in hill mountain areas. In a three-year average, the application of 150 kg ha-1 N had significant impact on cocksfoot population density (number of tillers m-2, and it was 51.4 % higher than the recorded one before grazing (P<0.05 and 42.2 % higher after grazing (P<0.01 in comparison to N0. The application of 150 kg ha-1 N resulted in significantly higher cocksfoot dry matter (DM yield for 38.6 % (P<0.01 and 15.3 % higher cocksfoot share in the total mixture in relation to N0 (P<0.01. Grazing management and grazing management interaction with N rate did not significantly affect the population density of individual years. However, in the three-year average, grazing management significantly affected cocksfoot DM (P<0.01 and its percentage in the total DM mixture (P<0.01. Cattle grazing resulted in 9.9 % higher cocksfoot DM yield and 15.2 % higher cocksfoot percentage in pasture. Interaction of grazing management and N-level had significant influence on the percentage of cocksfoot DM in grass-clover mixture. On cattle grazed areas fertilized with 150 kg ha-1 N, the percentage of cocksfoot DM was the highest (74. 07%, while the lowest percentage of cocksfoot DM was recorded on the sheep grazed areas without N (55.12%.

  9. Steering characteristic of an articulated bus under quasi steady maneuvering

    Science.gov (United States)

    Ubaidillah, Setiawan, Budi Agus; Aridharma, Airlangga Putra; Lenggana, Bhre Wangsa; Caesar, Bernardus Placenta Previo

    2018-02-01

    Articulated buses have been being preferred as public transportation modes due to their operational capacity. Therefore, passenger safety must be the priority of this public service vehicle. This research focused on the analytical approach of steering characteristics of an articulated bus when it maneuvered steadily. Such turning condition could be referred as a stability parameter of the bus for preliminary handling assessment. The analytical approach employed kinematics relationship between front and rear bodies as well as steering capabilities. The quasi steady model was developed to determine steering parameters such as turning radius, oversteer, and understeer. The mathematical model was useful for determining both coefficients of understeer and oversteer. The dimension of articulated bus followed a commonly used bus as utilized in Trans Jakarta busses. Based on the simulation, for one minimum center of the body, the turning radius was calculated about 8.8 m and 7.6 m at steady turning speed of 10 km/h. In neutral condition, the minimum road radius should be 6.5 m at 10 km/h and 6.9 m at 40 km/h. For two centers of the body and oversteer condition, the front body has the turning radius of 8.8 m, while, the rear body has the turning radius of 9.8 m at both turning speeds of 40 km/h. The other steering parameters were discussed accordingly.

  10. Arbuscular mycorrhizal fungi associated with vegetation and soil parameters under rest grazing management in a desert steppe ecosystem.

    Science.gov (United States)

    Bai, Gegenbaoleer; Bao, Yuying; Du, Guoxin; Qi, Yunlong

    2013-05-01

    The impact of rest grazing on arbuscular mycorrhizal fungi (AMF) and the interactions of AMF with vegetation and soil parameters under rest grazing condition were investigated between spring and late summer in a desert steppe ecosystem with different grazing managements (rest grazing with different lengths of resting period, banned or continuous grazing) in Inner Mongolia, China. AMF diversity and colonization, vegetation biomass, soil properties and soil phosphatase activity were examined. In rest grazing areas of 60 days, AMF spore number and diversity index at a 0-10 cm soil depth as well as vesicular and hyphal colonization rates were higher compared with other grazing treatments. In addition, soil organic matter and total N contents were highest and soil alkaline phosphatase was most active under 60-day rest grazing. In August and September, these areas also had the highest amount of aboveground vegetation. The results indicated that resting grazing for an appropriate period of time in spring has a positive effect on AMF sporulation, colonization and diversity, and that under rest grazing conditions, AMF parameters are positively correlated with some soil characteristics.

  11. Behavioral characteristics of Hanwoo ( steers at different growth stages and seasons

    Directory of Open Access Journals (Sweden)

    Na Yeon Kim

    2017-10-01

    Full Text Available Objective This research analyzed behavioral characteristics of Hanwoo (Bos taurus coreanae steers during each season and growth stage to enable measurement of the animals’ welfare level for precision livestock farming. Methods A hundred-eight beef steers were divided into three equal groups at a Hanwoo farm according to their growth stage: growing stage (GS, 8 months; early-fattening stage (EFS, 19 months; and late-fattening stage (LFS, 30 months. Twelve behavioral categories were continuously recorded for 13 day-time hours in each four seasons with three replications. Results Time spent standing was found to be significantly longer in summer at all growth stages (p<0.05. Hanwoos at the GS spent significantly longer standing time in spring and summer than those at the EFS and LFS (p<0.05. Lying time in summer was the shortest for all growth stages (p<0.05. Steers at the LFS spent significantly longer lying time than that at the GS (p<0.05 in summer. For GS and EFS, time spent eating in spring and autumn were longer than in summer and winter (p<0.05. Eating time was the longest for the GS in spring, autumn, and winter, excluding for the LFS in winter (p<0.05. Regarding ruminating, steers at the LFS spent significantly shorter time than those at other stages in all seasons (p<0.05. GS and EFS steers showed the longest walking time in summer compared with other seasons (p<0.05. At GS and LFS, drinking time in summer was the longest of all seasons (p<0.05. Sleeping time was significantly shorter in summer compared with the other seasons (p<0.05. Self-grooming time was the longest in winter for all growth stages (p<0.05. Conclusion Steers were found to have more variable behavioral patterns during summer and the GS and less active behaviors during the LFS, thus extra care seems necessary during the GS, LFS, and summer period.

  12. Strategic grazing management towards sustainable intensification at tropical pasture-based dairy systems.

    Science.gov (United States)

    Congio, Guilhermo F S; Batalha, Camila D A; Chiavegato, Marília B; Berndt, Alexandre; Oliveira, Patrícia P A; Frighetto, Rosa T S; Maxwell, Thomas M R; Gregorini, Pablo; Da Silva, Sila C

    2018-05-01

    Agricultural systems are responsible for environmental impacts that can be mitigated through the adoption of more sustainable principles. Our objective was to investigate the influence of two pre-grazing targets (95% and maximum canopy light interception during pasture regrowth; LI 95% and LI Max , respectively) on sward structure and herbage nutritive value of elephant grass cv. Cameroon, and dry matter intake (DMI), milk yield, stocking rate, enteric methane (CH 4 ) emissions by Holstein × Jersey dairy cows. We hypothesized that grazing strategies modifying the sward structure of elephant grass (Pennisetum purpureum Schum.) improves nutritive value of herbage, increasing DMI and reducing intensity of enteric CH 4 emissions, providing environmental and productivity benefits to tropical pasture-based dairy systems. Results indicated that pre-sward surface height was greater for LI Max (≈135 cm) than LI 95% (≈100 cm) and can be used as a reliable field guide for monitoring sward structure. Grazing management based on LI 95% criteria improved herbage nutritive value and grazing efficiency, allowing greater DMI, milk yield and stocking rate by dairy cows. Daily enteric CH 4 emission was not affected; however, cows grazing elephant grass at LI 95% were more efficient and emitted 21% less CH 4 /kg of milk yield and 18% less CH 4 /kg of DMI. The 51% increase in milk yield per hectare overcame the 29% increase in enteric CH 4 emissions per hectare in LI 95% grazing management. Thereby the same resource allocation resulted in a 16% mitigation of the main greenhouse gas from pasture-based dairy systems. Overall, strategic grazing management is an environmental friendly practice that improves use efficiency of allocated resources through optimization of processes evolving plant, ruminant and their interface, and enhances milk production efficiency of tropical pasture-based systems. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Emergy analysis of cropping-grazing system in Inner Mongolia Autonomous Region, China

    International Nuclear Information System (INIS)

    Zhang, L.X.; Yang, Z.F.; Chen, G.Q.

    2007-01-01

    An ecological energetic evaluation is presented in this paper as a complement to economic account for the cropping-grazing system in the Inner Mongolia Autonomous Region in China in the year 2000. Based on Odum's well-known concept of emergy in terms of embodied solar energy as a unified measure for environmental resources, human or animal labors and industrial products, a systems diagram is developed for the crop and livestock productions with arms and sub-arms for free renewable natural resource input, purchased economic investment, yields of and interactive fluxes between the cropping and grazing sub-industries. In addition to conventional systems indices of the emergy yield ratio (EYR), emergy investment ratio (EIR), environmental load ratio (ELR) and environmental sustainability index (ESI) introduced for congregated systems ecological assessment with essential implication for sustainability, new indicators of soil emergy cost (SEC), self-support intensity (SSI) and self-support orientation (SSO) are defined to characterize the desertification and internal recycling associated with the special agricultural system. Extensive emergy accounting is made for the cropping-grazing system as a whole as well as for the cropping and grazing subsystems. The overall cropping-grazing system is shown with outstanding production competence compared with agricultural systems in some other provinces and the national average in China, though confronted with severe desertification associated with soil loss. The production of crops has higher emergy density and yield rate per unit area as well as higher rate of soil loss than grazing system. The soil emergy cost defined as the soil loss emergy divided by the yield emergy is estimated to be of the same value for both of the subsystems, but the grazing activity is with less extraction intensity, leaving rangeland to rest and rehabilitate. Suggestions with regard to the local sustainability and national ecological security in

  14. Butterfly responses to prairie restoration through fire and grazing

    Science.gov (United States)

    Vogel, Jennifer A.; Debinski, Diane M.; Koford, Rolf R.; Miller, J.R.

    2007-01-01

    The development of land for modern agriculture has resulted in losses of native prairie habitat. The small, isolated patches of prairie habitat that remain are threatened by fire suppression, overgrazing, and invasion by non-native species. We evaluated the effects of three restoration practices (grazing only, burning only, and burning and grazing) on the vegetation characteristics and butterfly communities of remnant prairies. Total butterfly abundance was highest on prairies that were managed with burning and grazing and lowest on those that were only burned. Butterfly species richness did not differ among any of the restoration practices. Butterfly species diversity was highest on sites that were only burned. Responses of individual butterfly species to restoration practices were highly variable. In the best predictive regression model, total butterfly abundance was negatively associated with the percent cover of bare ground and positively associated with the percent cover of forbs. Canonical correspondence analysis revealed that sites with burned only and grazed only practices could be separated based on their butterfly community composition. Butterfly communities in each of the three restoration practices are equally species rich but different practices yield compositionally different butterfly communities. Because of this variation in butterfly species responses to different restoration practices, there is no single practice that will benefit all species or even all species within habitat-specialist or habitat-generalist habitat guilds. ?? 2007 Elsevier Ltd. All rights reserved.

  15. Physical impact of grazing by sheep on the dynamics of Nama ...

    African Journals Online (AJOL)

    UFS

    Physical impact of sheep grazing on arid Karoo subshrub/grass rangeland,. South Africa ... sustainability of rangeland resources, soil and vegetation responses to various grazing systems (Teague &. Dowhower .... The only significant decrease (F3,4 = 18.14, P <0.01) in basal cover of the total herbaceous layer for the 1995 ...

  16. Temporal profiles of vegetation indices for characterizing grazing intensity on natural grasslands in Pampa biome

    Directory of Open Access Journals (Sweden)

    Amanda Heemann Junges

    2016-08-01

    Full Text Available ABSTRACT The Pampa biome is an important ecosystem in Brazil that is highly relevant to livestock production. The objective of this study was to analyze the potential use of vegetation indices to discriminate grazing intensities on natural grasslands in the Pampa biome. Moderate Resolution Imaging Spectroradiometer (MODIS Normalized Difference Vegetation Index (NDVI and Enhanced Vegetation Index (EVI images from Jan to Dec, 2000 to 2013 series, were analyzed for natural grassland experimental units managed under high (forage allowance of 5 ± 2 % live weight – LW, moderate (13 ± 5 % LW and low grazing intensity (19 ± 7 % LW. Regardless of intensity, the temporal profiles showed lower NDVI and EVI during winter, increased values in spring because of summer species regrowth, slightly decreased values in summer, especially in years when there is a water deficit, and increased values in the fall associated with the beginning of winter forage development. The average temporal profiles of moderate grazing intensity exhibited greater vegetation index values compared with low and high grazing intensities. The temporal profiles of less vegetation index were associated with lower green biomass accumulation caused by the negative impact of stocking rates on the leaf area index under high grazing intensity and a floristic composition with a predominance of tussocks under low grazing intensity. Vegetation indices can be used for distinguishing moderate grazing intensity from low and high intensities. The average EVI values can discriminate moderate grazing intensity during any season, and the NDVI values can discriminate moderate grazing intensity during spring and winter.

  17. Steering of Educational Processes in a Digital Medium Environment

    DEFF Research Database (Denmark)

    Tække, Jesper; Paulsen, Michael

    2015-01-01

    by systems theory we outline a more adequate way of teaching in the new medium environment – a teaching that can manage the new situation and use the new possibilities provided by the digital media. The argumentation builds on empirical findings from the action research project Socio Media Education (SME......This paper is about challenges to steering and leadership of educational interaction in classrooms provided by the new medium environment that comes with digital media. In the new medium environment, the old way of steering what is going on in the classroom appears not to work since...

  18. Range-wide assessment of livestock grazing across the sagebrush biome

    Science.gov (United States)

    Veblen, Kari E.; Pyke, David A.; Jones, Christopher A.; Casazza, Michael L.; Assal, Timothy J.; Farinha, Melissa A.

    2011-01-01

    Domestic livestock grazing occurs in virtually all sagebrush habitats and is a prominent disturbance factor. By affecting habitat condition and trend, grazing influences the resources required by, and thus, the distribution and abundance of sagebrush-obligate wildlife species (for example, sage-grouse Centrocercus spp.). Yet, the risks that livestock grazing may pose to these species and their habitats are not always clear. Although livestock grazing intensity and associated habitat condition may be known in many places at the local level, we have not yet been able to answer questions about use, condition, and trend at the landscape scale or at the range-wide scale for wildlife species. A great deal of information about grazing use, management regimes, and ecological condition exists at the local level (for individual livestock management units) under the oversight of organizations such as the Bureau of Land Management (BLM). However, the extent, quality, and types of existing data are unknown, which hinders the compilation, mapping, or analysis of these data. Once compiled, these data may be helpful for drawing conclusions about rangeland status, and we may be able to identify relationships between those data and wildlife habitat at the landscape scale. The overall objective of our study was to perform a range-wide assessment of livestock grazing effects (and the relevant supporting data) in sagebrush ecosystems managed by the BLM. Our assessments and analyses focused primarily on local-level management and data collected at the scale of BLM grazing allotments (that is, individual livestock management units). Specific objectives included the following: 1. Identify and refine existing range-wide datasets to be used for analyses of livestock grazing effects on sagebrush ecosystems. 2. Assess the extent, quality, and types of livestock grazing-related natural resource data collected by BLM range-wide (i.e., across allotments, districts and regions). 3. Compile and

  19. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Kappers, Astrid M.L.; Daanen, H.A.M.

    2012-01-01

    In daily life, people interact with textiles of different degrees of wetness, but little is known about the mechanics of wetness perception. This paper describes an experiment with six conditions regarding haptic discrimination of the wetness of fabrics. Three materials were used: cotton wool,

  20. Real-Time Application Performance Steering and Adaptive Control

    National Research Council Canada - National Science Library

    Reed, Daniel

    2002-01-01

    .... The objective of the Real-time Application Performance Steering and Adaptive Control project is to replace ad hoc, post-mortem performance optimization with an extensible, portable, and distributed...

  1. Investigations on the effect of grazing intensity on the transfer of radionuclides to cow`s milk

    Energy Technology Data Exchange (ETDEWEB)

    Voigt, G. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz; Schotola, C. [GSF - Forschungszentrum fuer Umwelt und Gesundheit Neuherberg GmbH, Oberschleissheim (Germany). Inst. fuer Strahlenschutz; Crout, N.M.J. [Nottingham Univ. (United Kingdom). Dept. of Physiology and Environmental Science; Absalom, J. [Nottingham Univ. (United Kingdom). Dept. of Physiology and Environmental Science

    1997-03-01

    For these investigations two farms were chosen. Farm A carries out a rotational grazing regime with 4 grazed pastures which is the more commonly used farm practice in Bavaria, farm B practises a continuous grazing regime with one grazed pasture only. In farm B a tenfold lower Cs-137 activity concentration was observed in milk though activity concentrations in soil and pasture grass were the same as that at farm A, indicating the same transfer rate soil-plant at both locations. It could be shown under normal agricultural conditions that with a higher grazing pressure lower activity concentrations in milk (in this case a factor of about 2 to 3) were obtained. Therefore changing stock density in combination with a continuous grazing regime on a given pasture after a major nuclear accident can be considered as a possible countermeasure which can be easily applied. Mainly to get more synchronised growth rates and a homogeneous distribution of radiocontamination plot experiments were performed to simulate the influence of grazing intensity. Under the experimental design used here no effect of grazing intensity on the transfer of radionuclides to vegetation could be found. Effects of grazing intensity as found for the farm experiment, therefore must be due to other sources than vegetation activities, and are presumably due to soil ingestion preventing uptake of soluble plant incorporated radiocaesium in the animal rumen. (orig./MG)

  2. Excitation Patterns of Standard and Steered Partial Tripolar Stimuli in Cochlear Implants.

    Science.gov (United States)

    Wu, Ching-Chih; Luo, Xin

    2016-04-01

    Current steering in partial tripolar (pTP) mode has been shown to improve pitch perception and spectral resolution with cochlear implants (CIs). In this mode, a fraction (σ) of the main electrode current is returned within the cochlea and steered between the basal and apical flanking electrodes (with a proportion of α and 1 - α, respectively). Pitch generally decreases when α increases from 0 to 1, although the salience of pitch change varies across CI users. This study aimed to identify the mechanism of pitch changes with pTP-mode current steering and the factors contributing to the intersubject variability in pitch-ranking sensitivity. The electrical fields were measured for steered pTP stimuli on the same main electrode with α = 0, 0.5, and 1 in five implanted ears using electrical field imaging (EFI). The related excitation patterns were also measured physiologically using evoked compound action potential (ECAP) and psychophysically using psychophysical forward masking (PFM). Consistent with the pitch-ranking results in this study, the EFI, ECAP, and PFM centroids shifted apically with increasing α. An apical shift was also observed for the PFM peak but not for the EFI or ECAP peak. The pattern width was similar with different α values within a given measure (e.g., EFI, ECAP, or PFM), but the ECAP patterns were broader than the EFI and PFM patterns, possibly because ECAP was measured with smaller σ values than EFI and PFM. The amount of pattern shift with α depended on σ (i.e., the total amount of current used for steering) but was not correlated with the pitch-ranking sensitivity across subjects. The results revealed that the pitch changes elicited by pTP-mode current steering were not only driven by the shifts of excitation centroid.

  3. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Kosters, N.D.; Daanen, H.A.M.; Kappers, A.M.L.

    2011-01-01

    The sensation of wetness is well-known but barely investigated. There are no specific wetness receptors in the skin, but the sensation is mediated by temperature and pressure perception. In our study, we have measured discrimination thresholds for the haptic perception of wetness of three di erent

  4. Haptic perception of wetness

    NARCIS (Netherlands)

    Bergmann Tiest, W.M.; Dolfine Kosters, N.; Daanen, h.a.m.; Kappers, A.M.L.

    2012-01-01

    In daily life, people interact with textiles of different degrees of wetness, but little is known about the me-chanics of wetness perception. This paper describes an experiment with six conditions regarding haptic dis-crimination of the wetness of fabrics. Three materials were used: cotton wool,

  5. Rotation grazing as a conservation management tool : Vegetation changes after six years of application in a salt marsh ecosystem

    NARCIS (Netherlands)

    Lagendijk, D. D. Georgette; Howison, Ruth A.; Esselink, Peter; Ubels, Richard; Smit, Christian

    2017-01-01

    Grazing is commonly used in conservation to promote biodiversity, but the search for a grazing management regime that optimises biodiversity is still ongoing. Rotation grazing, where grazing is followed by a relatively long period of non-grazing, is a relative new tool in conservation management,

  6. A Parallel and Distributed Surrogate Model Implementation for Computational Steering

    KAUST Repository

    Butnaru, Daniel

    2012-06-01

    Understanding the influence of multiple parameters in a complex simulation setting is a difficult task. In the ideal case, the scientist can freely steer such a simulation and is immediately presented with the results for a certain configuration of the input parameters. Such an exploration process is however not possible if the simulation is computationally too expensive. For these cases we present in this paper a scalable computational steering approach utilizing a fast surrogate model as substitute for the time-consuming simulation. The surrogate model we propose is based on the sparse grid technique, and we identify the main computational tasks associated with its evaluation and its extension. We further show how distributed data management combined with the specific use of accelerators allows us to approximate and deliver simulation results to a high-resolution visualization system in real-time. This significantly enhances the steering workflow and facilitates the interactive exploration of large datasets. © 2012 IEEE.

  7. Grazing impact on desert plants and soil seed banks: Implications for seed-eating animals

    Science.gov (United States)

    Pol, Rodrigo G.; Sagario, M. Cecilia; Marone, Luis

    2014-02-01

    We assess whether the knowledge of livestock diet helps to link grazing effects with changes in plant cover and soil seed bank size, aiming at inferring the consequences of grazing on seed-eating animals. Specifically, we test whether continuous and heavy grazing reduce the cover, number of reproductive structures and seed reserves of the same grass species whose seeds are selected and preferred by granivorous animals in the central Monte desert, Argentina. Grass cover and the number of grass spikes usually diminished under grazing conditions in the two localities studied (Telteca and Ñacuñán), and soil seed bank was consistently reduced in all three years evaluated owing to a decline of perennial grass and forb seeds. In particular, the abundance of those seeds selected and preferred by birds and ants (in all cases grass species) declined 70-92% in Ñacuñán, and 52-72% in Telteca. Reduction of perennial grass cover and spike number in grazed sites reinforced the causal link between livestock grazing and the decline of grass soil seed reserves throughout failed plant reproduction. Grass seed bank depletion suggests that grazing may trigger a "cascade" of mechanisms that affect the abundance and persistence of valuable fodder species as well as the availability of seed resources for granivorous animals.

  8. Some effects of winter grazing of Dohne sour veld | PF | African ...

    African Journals Online (AJOL)

    The utilisation of spared sour veld poses practical problems. As a result of the development of high level protein or nitrogen supplements it has however become possible to efficiently graze spared veld. Results of experiments during three winters where spared sour veld was grazed off either by sheep or by cattle are given.

  9. Influence of grazing regimes on cattle nutrition and performance and vegetation dynamics in Sahelian rangelands

    NARCIS (Netherlands)

    Ayantunde, A.A.

    1998-01-01

    In the West African Sahel, common herd management practices such as night grazing and corralling influence time available for grazing. When animals are used to deposit manure in the cropping fields, conflicts often arise between the need for animals to graze long enough for adequate feed

  10. Multi-Layer Traffic Steering

    DEFF Research Database (Denmark)

    Fotiadis, Panagiotis; Polignano, Michele; Gimenez, Lucas Chavarria

    2013-01-01

    This paper investigates the potentials of traffic steering in the Radio Resource Control (RRC) Idle state by evaluating the Absolute Priorities (AP) framework in a multilayer Long Term Evolution (LTE) macrocell scenario. Frequency priorities are broadcast on the system information and RRC Idle...... periods are not significantly long. Finally, better alignment between the RRC Connected and Idle mobility procedures is observed, guarantying significant decrease of handovers/reselections and potential battery life savings by minimizing the Inter-Frequency (IF) measurement rate in the RRC Idle....

  11. Progress on the ITER H&CD EC upper launcher steering-mirror control system

    NARCIS (Netherlands)

    Collazos, A.; Bertizzolo, R.; Chavan, R.; Dolizy, F.; Felici, F.; Goodman, T.P.; Henderson, M.A.; Landis, J.-D.; Sanchez, F.

    2010-01-01

    The ITER Heating and Current Drive Upper Launcher (H&CD EC UL) uses a pneumomechanical steering-mirror assembly (SMA) to steer the RF beams for their deposition in the appropriate location in the plasma to control magnetohydrodynamic activity (neoclassical tearing modes (NTMs) and sawtooth

  12. Utilization of water by buffaloes in adapting to a wet-tropical environment

    International Nuclear Information System (INIS)

    Ranawana, S.S.E.; Tilakaratne, M.; Srikandakumar, A.

    1984-01-01

    In a series of experiments some of the characteristics that might enable water buffaloes to adapt to hot and humid environments were investigated. Total body water and water turnover were related to measurements of respiratory and cutaneous evaporation rates and to rectal temperature. These measurements were made during different seasons in animals maintained in several agro-ecological zones. Water turnover was measured in unweaned Murrah buffalo calves; in growing, pregnant and lactating Surti buffaloes grazed under coconut with wallowing denied and drinking water restricted; in Murrah buffaloes and in Zebu and European cattle during different seasons in the 'wet zone', and on Murrah, Surti and Lanka buffaloes compared under 'dry-zone' conditions. Rates of water turnover in milk-fed buffalo calves were low but in adult buffaloes were higher than in other domestic ruminants. Water turnover was higher at higher air temperatures and during the monsoon when forage contained more water. Lactation and grazing in the sun also increased water turnover. A high rate of cutaneous water loss in buffaloes, apparently due to passive diffusion rather than to true sweating, may have contributed to the high water turnover in this species. A relatively labile body temperature enabled buffaloes to 'store' body heat which was dissipated quickly by wallowing, which was shown to be a major route of heat loss and to help in the maintenance of skin condition. If allowed adequate water for drinking and wallowing, buffaloes can apparently withstand hot humid environments but, in contrast to camels, sheep and goats, they seem unable to conserve water and their productivity is affected by any restriction of water supply. (author)

  13. Grazing management that regenerates ecosystem function and ...

    African Journals Online (AJOL)

    Grazing management that regenerates ecosystem function and grazingland ... in ecosystem improvement, productivity, soil carbon and fertility, water-holding ... for sufficient time to produce resource improvement, sound animal production, and ...

  14. Methane Emission By Grazing Livestock. A Synopsis Of 1000 Direct Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Lassey, K.R. [National Institute of Water and Atmospheric Research (NIWA), Wellington (New Zealand); Ulyatt, M.J. [New Zealand Pastoral Agriculture Research Institute (AgResearch), Palmerston North (New Zealand)

    2000-07-01

    In a series of field campaigns since 1995, a team of atmospheric and ruminant-nutrition scientists have measured methane emissions directly from individual ruminant livestock freely grazing representative New Zealand pastures. The technique collects integrated 'breath' samples during grazing, using an implanted SF6 source as a conservative calibrated tracer, an approach pioneered by Johnson et al. [1994]. Most of these measurements have been on grazing sheep (942 animal-days to Aug 1999), others on grazing dairy cows (283), with some measurements also on sheep under controlled feeding conditions (305) [eg, Lassey et al., 1997; Ulyatt et al., 1999]. The aim is to characterise the variability of emission rates, including their dependence on pasture quality and physiological condition. The research goal is two-fold: (1) to provide a better scientific basis for assessing the national emissions inventory; and (2) to investigate options for mitigating livestock emissions. Here, we discuss the research strategy and overview the principal research findings. We note in particular, that as a source of enterically fermented methane, sheep may not be merely 'small cattle'. 5 refs.

  15. Seasonal grazing and food preference of herbivores in a Posidonia oceanica meadow

    Directory of Open Access Journals (Sweden)

    Andrea Peirano

    2001-12-01

    Full Text Available Seasonal grazing of the fish Sarpa salpa (L., the urchin Paracentrotus lividus Lamarck and the isopods Idotea spp. was compared with the C/N ratio of adult and intermediate leaves and epiphytes of Posidonia oceanica (L. Delile, collected at three different depths. Despite seasonal differences in grazing, herbivores showed preferences throughout the year for adult leaves with more epiphyte and higher N contents. The maximum grazing on adult and intermediate leaves was observed in September and in June for fish and in March for urchins, whereas it was irregular for isopods. Grazing by the three herbivores was not related to their preference for leaves or epiphytes, notwithstanding the seasonal differences in their C and N contents. We concluded that herbivores show no preference for food type throughout the year and that seasonal consumption of P. oceanica is related mainly to herbivore behaviour.

  16. Revealing livestock effects on bunchgrass vegetation with Landsat ETM+ data across a grazing season

    Science.gov (United States)

    Jansen, Vincent S.

    Remote sensing provides monitoring solutions for more informed grazing management. To investigate the ability to detect the effects of cattle grazing on bunchgrass vegetation with Landsat Enhanced Thematic Mapper Plus (ETM+) data, we conducted a study on the Zumwalt Prairie in northeastern Oregon across a gradient of grazing intensities. Biophysical vegetation data was collected on vertical structure, biomass, and cover at three different time periods during the grazing season: June, August, and October 2012. To relate these measures to the remotely sensed Landsat ETM+ data, Pearson's correlations and multiple regression models were computed. Using the best models, predicted vegetation metrics were then mapped across the study area. Results indicated that models using common vegetation indices had the ability to discern different levels of grazing across the study area. Results can be distributed to land managers to help guide grassland conservation by improving monitoring of bunchgrass vegetation for sustainable livestock management.

  17. Modulation of the acute phase response in feedlot steers supplemented with Saccharomyces cerevisiae

    Science.gov (United States)

    This study was designed to determine the effect of supplementing feedlot steers with Saccharomyces cerevisiae CNCM I-1079 (SC) on the acute phase response to a lipopolysaccharide (LPS) challenge. Steers (n = 18; 266 ± 4 kilograms body weight) were separated into three treatment groups (n = 6/treatm...

  18. Three-bead steering microswimmers

    Science.gov (United States)

    Rizvi, Mohd Suhail; Farutin, Alexander; Misbah, Chaouqi

    2018-02-01

    The self-propelled microswimmers have recently attracted considerable attention as model systems for biological cell migration as well as artificial micromachines. A simple and well-studied microswimmer model consists of three identical spherical beads joined by two springs in a linear fashion with active oscillatory forces being applied on the beads to generate self-propulsion. We have extended this linear microswimmer configuration to a triangular geometry where the three beads are connected by three identical springs in an equilateral triangular manner. The active forces acting on each spring can lead to autonomous steering motion; i.e., allowing the swimmer to move along arbitrary paths. We explore the microswimmer dynamics analytically and pinpoint its rich character depending on the nature of the active forces. The microswimmers can translate along a straight trajectory, rotate at a fixed location, as well as perform a simultaneous translation and rotation resulting in complex curved trajectories. The sinusoidal active forces on the three springs of the microswimmer contain naturally four operating parameters which are more than required for the steering motion. We identify the minimal operating parameters which are essential for the motion of the microswimmer along any given arbitrary trajectory. Therefore, along with providing insights into the mechanics of the complex motion of the natural and artificial microswimmers, the triangular three-bead microswimmer can be utilized as a model for targeted drug delivery systems and autonomous underwater vehicles where intricate trajectories are involved.

  19. Grazing of particle-associated bacteria-an elimination of the non-viable fraction.

    Science.gov (United States)

    Gonsalves, Maria-Judith; Fernandes, Sheryl Oliveira; Priya, Madasamy Lakshmi; LokaBharathi, Ponnapakkam Adikesavan

    Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42h showed that at the end of 24h, growth coefficient (k) of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, 'k' value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g)=0.564), the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, 'g' of non-viable fraction (particle-associated bacteria=0.615, Free=0.0086) was much greater than the viable fraction (particle-associated bacteria=0.056, Free=0.068). Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the "persistent variants" where the viable fraction multiply and release their progeny. Copyright © 2016 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

  20. Reduced fine-scale spatial genetic structure in grazed populations of Dianthus carthusianorum.

    Science.gov (United States)

    Rico, Y; Wagner, H H

    2016-11-01

    Strong spatial genetic structure in plant populations can increase homozygosity, reducing genetic diversity and adaptive potential. The strength of spatial genetic structure largely depends on rates of seed dispersal and pollen flow. Seeds without dispersal adaptations are likely to be dispersed over short distances within the vicinity of the mother plant, resulting in spatial clustering of related genotypes (fine-scale spatial genetic structure, hereafter spatial genetic structure (SGS)). However, primary seed dispersal by zoochory can promote effective dispersal, increasing the mixing of seeds and influencing SGS within plant populations. In this study, we investigated the effects of seed dispersal by rotational sheep grazing on the strength of SGS and genetic diversity using 11 nuclear microsatellites for 49 populations of the calcareous grassland forb Dianthus carthusianorum. Populations connected by rotational sheep grazing showed significantly weaker SGS and higher genetic diversity than populations in ungrazed grasslands. Independent of grazing treatment, small populations showed significantly stronger SGS and lower genetic diversity than larger populations, likely due to genetic drift. A lack of significant differences in the strength of SGS and genetic diversity between populations that were recently colonized and pre-existing populations suggested that populations colonized after the reintroduction of rotational sheep grazing were likely founded by colonists from diverse source populations. We conclude that dispersal by rotational sheep grazing has the potential to considerably reduce SGS within D. carthusianorum populations. Our study highlights the effectiveness of landscape management by rotational sheep grazing to importantly reduce genetic structure at local scales within restored plant populations.

  1. Grazing of particle-associated bacteria-an elimination of the non-viable fraction

    Directory of Open Access Journals (Sweden)

    Maria-Judith Gonsalves

    Full Text Available Abstract Quantification of bacteria being grazed by microzooplankton is gaining importance since they serve as energy subsidies for higher trophic levels which consequently influence fish production. Hence, grazing pressure on viable and non-viable fraction of free and particle-associated bacteria in a tropical estuary controlled mainly by protist grazers was estimated using the seawater dilution technique. In vitro incubations over a period of 42 h showed that at the end of 24 h, growth coefficient (k of particle-associated bacteria was 9 times higher at 0.546 than that of free forms. Further, ‘k’ value of viable cells on particles was double that of free forms at 0.016 and 0.007, respectively. While bacteria associated with particles were grazed (coefficient of removal (g = 0.564, the free forms were relatively less grazed indicating that particle-associated bacteria were exposed to grazers in these waters. Among the viable and non-viable forms, ‘g’ of non-viable fraction (particle-associated bacteria = 0.615, Free = 0.0086 was much greater than the viable fraction (particle-associated bacteria = 0.056, Free = 0.068. Thus, grazing on viable cells was relatively low in both the free and attached states. These observations suggest that non-viable forms of particle-associated bacteria were more prone to grazing and were weeded out leaving the viable cells to replenish the bacterial standing stock. Particle colonization could thus be a temporary refuge for the “persistent variants” where the viable fraction multiply and release their progeny.

  2. Active Return-to-Center Control Based on Torque and Angle Sensors for Electric Power Steering Systems.

    Science.gov (United States)

    Du, Pan-Pan; Su, Hao; Tang, Gong-You

    2018-03-14

    This paper presents a complete control strategy of the active return-to-center (RTC) control for electric power steering (EPS) systems. We first establish the mathematical model of the EPS system and analyze the source and influence of the self-aligning torque (SAT). Second, based on the feedback signals of steering column torque and steering wheel angle, we give the trigger conditions of a state switch between the steering assist state and the RTC state. In order to avoid the sudden change of the output torque for the driving motor when the state switches frequently between the steering assist state and the RTC state, we design an undisturbed state switching logic algorithm. This state switching logic algorithm ensures that the output value of the RTC controller is set to an initial value and increases in given steps up to a maximum value after entering the RTC state, and the output value of the RTC controller will reduce in given steps down to zero when exiting the RTC state. This therefore ensures smooth switch control between the two states and improves the driver's steering feeling. Third, we design the RTC controller, which depends upon the feedback signals of the steering wheel angle and the angular velocity. In addition, the controller increases the auxiliary control function of the RTC torque based on vehicle speed. The experimental results show that the active RTC control method does not affect the basic assist characteristics, which effectively reduces the residual angle of the steering wheel at low vehicle speed and improves the RTC performance of the vehicle.

  3. Wet-Bulb-Globe Temperature Data Report

    Science.gov (United States)

    2015-03-01

    Hour Min Pressure Dry Nat Wet Globe Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S1 WBGT Q WBGT...Wet Globe Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S1 WBGT Q WBGT K2 WBGT GMT millibars deg F...Dry Nat Wet Globe Dry Nat Wet Globe Wind Cld amt Cld type Obscuration Quest RH Kestrel RH VPSc RH S1 WBGT Q WBGT K2 WBGT GMT millibars deg F deg F deg

  4. Multisensor sampling of pelagic ecosystem variables in a coastal environment to estimate zooplankton grazing impact

    Science.gov (United States)

    Sutton, Tracey; Hopkins, Thomas; Remsen, Andrew; Burghart, Scott

    2001-01-01

    Sampling was conducted on the west Florida continental shelf ecosystem modeling site to estimate zooplankton grazing impact on primary production. Samples were collected with the high-resolution sampler, a towed array bearing electronic and optical sensors operating in tandem with a paired net/bottle verification system. A close biological-physical coupling was observed, with three main plankton communities: 1. a high-density inshore community dominated by larvaceans coincident with a salinity gradient; 2. a low-density offshore community dominated by small calanoid copepods coincident with the warm mixed layer; and 3. a high-density offshore community dominated by small poecilostomatoid and cyclopoid copepods and ostracods coincident with cooler, sub-pycnocline oceanic water. Both high-density communities were associated with relatively turbid water. Applying available grazing rates from the literature to our abundance data, grazing pressure mirrored the above bio-physical pattern, with the offshore sub-pycnocline community contributing ˜65% of grazing pressure despite representing only 19% of the total volume of the transect. This suggests that grazing pressure is highly localized, emphasizing the importance of high-resolution sampling to better understand plankton dynamics. A comparison of our grazing rate estimates with primary production estimates suggests that mesozooplankton do not control the fate of phytoplankton over much of the area studied (<5% grazing of daily primary production), but "hot spots" (˜25-50% grazing) do occur which may have an effect on floral composition.

  5. Grazing-Activated Production of Dimethyl Sulfide (DMS) by two clones of Emiliania huxleyi

    Science.gov (United States)

    Wolfe, Gordon V.; Steinke, Michael

    1996-01-01

    Emiliania huxleyi clones CCMP 370 and CCMP 373 produced similar amounts of dimethylsulfoniopropionate (DMSP) during axenic exponential growth, averaging 109 mM internal DMSP. Both clones had detectable DMSP lyase activity, as measured by production of dimethyl sulfide (DMS) during in vitro assays of crude cell preparations, but activities and conditions differed considerably between clones. Clone 373 had high activity; clone 370 had low activity and required chloride. For both strains, enzyme activity per cell was constant during exponential growth, but little DMS was produced by healthy cells. Rather, DMS production was activated when cells were subjected to physical or chemical stresses that caused cell lysis. We propose that DMSP lyase and DMSP are segregated within these cells and re-action only under conditions that result in cell stress or damage. Such activation occurs during microzooplankton grazing. When these clones were grazed by the dinoflagellate Oxyrrhis marina, DMS was produced; ungrazed cells, as well as those exposed to grazer exudates and associated bacteria, generated no DMS. Grazing of clone 373 produced much more DMS than grazing of clone 370, consistent with their relative in vitro DMSP lyase activities. DMS was only generated when cells were actually being grazed, indicating that ingested cells were responsible for the DMS formation. We suggest that even low levels of grazing can greatly accelerate DMS production.

  6. Experimental nonlocal steering of Bohmian trajectories.

    Science.gov (United States)

    Xiao, Ya; Kedem, Yaron; Xu, Jin-Shi; Li, Chuan-Feng; Guo, Guang-Can

    2017-06-26

    Interpretations of quantum mechanics (QM), or proposals for underlying theories, that attempt to present a definite realist picture, such as Bohmian mechanics, require strong non-local effects. Naively, these effects would violate causality and contradict special relativity. However if the theory agrees with QM the violation cannot be observed directly. Here, we demonstrate experimentally such an effect: we steer the velocity and trajectory of a Bohmian particle using a remote measurement. We use a pair of photons and entangle the spatial transverse position of one with the polarization of the other. The first photon is sent to a double-slit-like apparatus, where its trajectory is measured using the technique of Weak Measurements. The other photon is projected to a linear polarization state. The choice of polarization state, and the result, steer the first photon in the most intuitive sense of the word. The effect is indeed shown to be dramatic, while being easy to visualize. We discuss its strength and what are the conditions for it to occur.

  7. Summary report of the grazing studies conducted on a plutonium-contaminated range in Area 13 of the Nevada Test Site

    International Nuclear Information System (INIS)

    Smith, D.D.

    1979-05-01

    Actinide concentrations in the tissues of beef animals periodically sacrificed and sampled during a 3-year grazing study on a plutonium-contaminated range of the Nevada Test Site are tabulated and discussed. The primary objective of this study was to determine the uptake and tissue distribution of the plutonium by ruminants. Food habit analyses of ingesta from rumen-fistulated steers and sacrificed cattle revealed that shrub species made up the major portion of their diet during most seasons of the year. Grasses were preferred during the spring months. Using activity levels found in the rumen contents, it was estimated that a study cow ingested 100 microcuries of plutonium-239 prior to sacrifice. Of this, 16.4 microcuries was in rumen fluids from which a combined retention factor of 0.0034% was calculated for the bone, muscle, and liver. Comparisons of plutonium-239/plutonium-238 ratios in ingesta and tissues indicate that the plutonium-238 is more readily absorbed and retained. No radiologically significant lesions were found. The gonadal concentrations of the actinides were significantly higher than those of blood and muscle and approached those of bone. These data indicate that consideration should be given to the plutonium-239 dose to gonads as well as that to bone, liver, and lungs of man. Actinide concentrations of animals born in the study areas showed an increasing trend with time. Concentrations of plutonium-239 in the lung, liver, muscle, and femur tissues of the Area 13 cattle were significantly higher than in tissues collected from grazing cattle from other sites. The plutonium-239 concentrations in bones, lungs, and livers collected from wildlife with free access to and from the contaminated zones reflect the dilution resulting from these animals ranging into the less contaminated areas around the study sites

  8. Grazing management, resilience and the dynamics of a fire driven rangeland system

    NARCIS (Netherlands)

    Anderies, J.M.; Janssen, M.A.; Walker, B.H.

    2002-01-01

    We developed a stylized mathematical model to explore the effects of physical, ecological, and economic factors on the resilience of a managed fire-driven rangeland system. Depending on grazing pressure, the model exhibits one of three distinct configurations: a fire-dominated, grazing-dominated, or

  9. Effects of buffer strips and grazing management on soil loss from pastures

    Science.gov (United States)

    Intensive grazing pressure can cause soil erosion from pastures causing increased sediment loading to aquatic systems. The objectives of this work were to determine the long-term effects of grazing management and buffer strips on soil erosion from pastures fertilized with broiler litter. Field stud...

  10. Einstein-Podolsky-Rosen steering: Its geometric quantification and witness

    Science.gov (United States)

    Ku, Huan-Yu; Chen, Shin-Liang; Budroni, Costantino; Miranowicz, Adam; Chen, Yueh-Nan; Nori, Franco

    2018-02-01

    We propose a measure of quantum steerability, namely, a convex steering monotone, based on the trace distance between a given assemblage and its corresponding closest assemblage admitting a local-hidden-state (LHS) model. We provide methods to estimate such a quantity, via lower and upper bounds, based on semidefinite programming. One of these upper bounds has a clear geometrical interpretation as a linear function of rescaled Euclidean distances in the Bloch sphere between the normalized quantum states of (i) a given assemblage and (ii) an LHS assemblage. For a qubit-qubit quantum state, these ideas also allow us to visualize various steerability properties of the state in the Bloch sphere via the so-called LHS surface. In particular, some steerability properties can be obtained by comparing such an LHS surface with a corresponding quantum steering ellipsoid. Thus, we propose a witness of steerability corresponding to the difference of the volumes enclosed by these two surfaces. This witness (which reveals the steerability of a quantum state) enables one to find an optimal measurement basis, which can then be used to determine the proposed steering monotone (which describes the steerability of an assemblage) optimized over all mutually unbiased bases.

  11. Design of a steering stabilizer based on CAN bus

    Science.gov (United States)

    Zhan, Zhaomin; Yan, Yibin

    2018-04-01

    This design realizes a posture correction device of griping steering wheel based on CAN bus, which is embedded in the steering wheel of vehicles. The system aims to detect the drivers' abnormal griping postures and provides drivers with classification alerts, by combining the recorded griping postures data and the vehicle speed data that are obtained via the CAN bus. The warning information are automatically stored and retained in the device for 12 months. To enhance the alerting effect, the count of this warning message for both the latest month and the last 12 months are displayed on the dashboard panel. In addition to prevent itself from being blocked and self-detect any faults in advance, the appliance also provide a self-test function, which will communicate with the integrated instrument system in vehicle and do simulation test right after the vehicle power on. This appliance can help to urge and ensure drivers to operate the steering wheel correctly, effectively, and timely; prevent some typical incorrect behaviors which commonly happen along with the change of griping postures, such as the using cellphone, and ultimately, reduce the incidence of traffic accidents.

  12. Grazer-induced chain lenght plasticity reduces grazing risk in a marine diatom

    DEFF Research Database (Denmark)

    Bergkvist, Johanna; Thor, Peter; Jakobsen, Hans Henrik

    2012-01-01

    . marinoi was exposed to chemical cues from caged A. tonsa without physical contact with the responding cells. The reductions in chain length significantly reduced copepod grazing; grazing rates on chains (four cells or more) were several times higher compared to that of single cells. This suggests...... that chain length plasticity is a means for S. marinoi to reduce copepod grazing. In contrast, chain length was not suppressed in cultures exposed to the microzooplankton grazer Gyrodinium dominans. Size-selective predation may have played a key role in the evolution of chain formation and chain length...... plasticity in diatoms...

  13. Improved grazing activity of dairy heifers in shaded tropical grasslands

    Directory of Open Access Journals (Sweden)

    Andréia Cristina Tavares de Mello

    Full Text Available ABSTRACT: Trees in the production systems can effectively reduce hot weather-induced stress in the Brazilian Midwest. High temperatures cause changes in animals daily routine, and trees into pastures can promote benefits. The aim of this research was to evaluate the behavior of dairy heifers in silvopastoral systems in the state of Mato Grosso, Brazil. A herd of 24 crossbreed heifers (3/4 and 7/8 Holstein/Zebu, 350kg average weight, was evaluated over three seasons. Piatã grass was managed under three shade levels: full-sun, moderate-shade, and intensive-shade provided by 10 to 12m high Eucalyptus trees. Behavior data were collected every 15 minutes from 8:30h to 16h. Shade availability significantly impacted heifer behavior, mainly affecting grazing frequency and time during the hottest hours. Grazing behavior was affected by shade levels during the different seasons. Heifers showed preferred grazing times. Heifers in the intensive-shade system visited shady areas during the hottest hours throughout the seasons. Heifers in the full sun-system avoided grazing during the warmer times, ceasing feeding activities. Our results from the Brazilian Midwest showed that shade availability causes breed heifers to change their daily routine.

  14. In situ provision of drinking water to grazing dairy cows improves milk production.

    Science.gov (United States)

    Miglierina, M M; Bonadeo, N; Ornstein, A M; Becú-Villalobos, D; Lacau-Mengido, I M

    2018-01-01

    To determine the effect of providing water within the area grazed by dairy cows on milk yield and quality, compared to requiring cows to walk to a distant water trough, on a dairy farm in the Pampa region of Argentina during summer. Holstein dairy cows were allocated to two herds with similar parity, days in milk and milk production. They were grazed in one paddock that was divided in two, with a fixed water trough at one end. Cows were moved twice daily to grazing plots within the paddock. Control cows (n=66) could only access water from the fixed trough, whereas supplemented cows (n=67) also received water from a mobile trough within the grazing plot. Milk production of each cow, and water consumption of the two herds were measured daily over 62 days. Milk composition for each herd was determined weekly from Days 18 to 60 of the study, and grazing behaviour was observed between 08:00 and 16:00 hours on Days 11-15, 19-22 and 39-43. Over the 62 days of the study, supplemented cows produced 1.39 (SE 0.11) L/cow/day more milk than Control cows (p=0.027). Estimated mean daily water intake was 50.4 (SE 2.1) L/cow/day for supplemented cows and 58.2 (SE 2.7) L/cow/day for Control cows (p=0.004). Percentage total solids in milk was higher for supplemented (12.5 (SE 0.06)%) than Control (12.4 (SE 0.04)%) cows (p=0.047). During the periods of behavioural observation, a higher percentage of cows in the water supplemented than the Control herd were observed in the grazing area (p=0.012). This preliminary study demonstrated that provision of water to dairy cows within the grazing plot was beneficial for milk production and composition, and may be associated with longer periods spent within the grazing area, during hot weather in the Pampa region of Argentina.

  15. Concentrate Supplement Modifies the Feeding Behavior of Simmental Cows Grazing in Two High Mountain Pastures.

    Science.gov (United States)

    Romanzin, Alberto; Corazzin, Mirco; Piasentier, Edi; Bovolenta, Stefano

    2018-05-16

    During grazing on Alpine pastures, the use of concentrates in dairy cows' diet leads to a reduction of the environmental sustainability of farms, and influences the selective pressure on some plant species. In order to minimize the use of concentrates, it is imperative to obtain data on the grazing behavior of cows. The aim of this study was to assess the effect of concentrate levels on the behavior of dairy cows during grazing. One hundred and ten lactating Italian Simmental cows, that sequentially grazed two pastures characterized by Poion alpinae (Poion) and Seslerion caeruleae (Seslerion) alliance, were considered. For each pasture, eight cows were selected and assigned to two groups: High and Low, supplemented with 4 kg/head/d, and 1 kg/head/d of concentrate respectively. Cows were equipped with a noseband pressure sensor and a pedometer (RumiWatch system, ITIN-HOCH GmbH) to assess grazing, ruminating, and walking behavior. In addition, the plant selection of the animals was assessed. On Poion, increased supplement intake caused a more intense selection of legumes, without affecting feeding and walking times. On Seslerion, grazing time was higher in Low than High. Grazing management in alpine region must take into account the great variability of pastures that largely differ from a floristic and nutritional point of view.

  16. Short-term spider community monitoring after cattle removal in grazed grassland

    Directory of Open Access Journals (Sweden)

    Guilherme O. da Silva

    2017-10-01

    Full Text Available ABSTRACT. At the Pampa Biome, grazing, like others disturbances, affects fauna and flora, creating heterogeneity in the environment. Little is known about how the diversity and richness of arthropods change during this impact. To improve the knowledge of how spider diversity is affected by grazing, experiments were realized at Pampa. The hypothesis is that abundance of spider will be different when comparing grazed and ungrazed areas. A paired block, with two areas of one hectare each, was established in three areas in the Environmental Protection Area of Ibirapuitã (APA Ibirapuitã, state of Rio Grande do Sul, Brazil. One of these hectares was closed with fences, excluding the catle grazing, in August of 2012. Samplings were realized in November of 2011, 2012 and 2013 using Pitfall traps filled with formol 4% and disposed in an “X” format in each area. For statistical analyses, T test, ANOSIM, ANOVA and Rarefaction were performed. A total of 1,315 spiders were captured, comprising 77 species or morphospecies belonging to 20 families. The family most abundant was Lycosidae followed by Hahniidae, Linyphiidae and Theridiidae. Linyphiidae was the richest family with 14 species or morphospecies identified. All spiders, adults and juveniles, only adults in species and morphospecies, and most abundant species were used as models for statistics. These models revealed no significant difference between grazed and ungrazed areas after three and 15 months of cattle exclusion.

  17. Dairy cattle on Norwegian alpine rangelands – grazing preferences and milk quality

    NARCIS (Netherlands)

    Sickel, H; Abrahamsen, R K; Eldegard, K; Lunnan, T; Norderhaug, A; Petersen, M.A.; Sickel, M.; Steenhuisen, F.; Ohlson, M.

    2014-01-01

    The results from the study ‘Effects of vegetation and grazing preferences on the quality of alpine dairy products’ will be presented. The main objective of the project was to investigate the connections bet - ween alpine rangeland vegetation, landscape use and grazing preferences of free ranging

  18. Studies of steered arc motion and macroparticle production in PVD processing

    International Nuclear Information System (INIS)

    Craven, A.L.

    2000-03-01

    During the past decade the production industry has constantly strived to improve performance and cut costs, this has been aided by the development of high performance tools. The advancement of these tools has been accomplished by the application of hard wearing, low friction, coatings. A key process in the production of such coatings is Physical Vapour Deposition (PVD). Interest in such thin films has led to much research effort, both academic and industrial, being devoted to the area. In order that these advancements in technology continue, research into the fundamental aspects of PVD is required. This thesis describes research and experimental studies which have been performed to study the effect of 'steering' an electric arc on various aspects of its behaviour. 'Steering' of the arc is achieved by applying external magnetic fields which allow the guidance of the path of the arc. Work by earlier authors has aimed to control the arc more fully. The research presented here is based of a novel electromagnetic three coil steering array of cylindrical geometry. With such coils it is possible to vary the field profiles to a greater degree than has been previously achieved, permitting a greater range of steering arrangements/fields to be applied. The research presented is divided into two distinct areas: Firstly a number of experiments were performed to assess the effectiveness of the new steering coils on the motion of the arc. A personal computer was used here along with new arc motion monitoring electronics. This enabled the simultaneous measurement of the orbital transit times and also the degree of travel perpendicular to the steered direction of motion of the arc, as it traversed the surface of the cathode. Such information was then used to produce values for standard deviation of the arc from its steered path, velocity of the arc and a diffusion constant related to the motion of the are. Such values then allowed evaluation of the stochastic model of arc motion

  19. Control of intravascular catheters using an array of active steering coils.

    Science.gov (United States)

    Gudino, N; Heilman, J A; Derakhshan, J J; Sunshine, J L; Duerk, J L; Griswold, M A

    2011-07-01

    To extend the concept of deflecting the tip of a catheter with the magnetic force created in an MRI system through the use of an array of independently controllable steering coils located in the catheter tip, and to present methods for visualization of the catheter and/or surrounding areas while the catheter is deflected. An array of steering coils made of 42-gauge wire was built over a 2.5 Fr (0.83 mm) fiber braided microcatheter. Two of the coils were 70 turn axial coils separated by 1 cm, and the third was a 15-turn square side coil that was 2 x 4 mm2. Each coil was driven independently by a pulse width modulation (PWM) current source controlled by a microprocessor that received commands from a MATLAB routine that dynamically set current amplitude and direction for each coil. The catheter was immersed in a water phantom containing 1% Gd-DTPA that was placed at the isocenter of a 1.5 T MRI scanner. Deflections of the catheter tip were measured from image-based data obtained with a real-time radio frequency (RF) spoiled gradient echo sequence (GRE). The small local magnetic fields generated by the steering coils were exploited to generate a hyperintense signal at the catheter tip by using a modified GRE sequence that did not include slice-select rewinding gradients. Imaging and excitation modes were implemented by synchronizing the excitation of the steering coil array with the scanner by ensuring that no current was driven through the coils during the data acquisition window; this allowed visualization of the surrounding tissue while not affecting the desired catheter position. Deflections as large as 2.5 cm were measured when exciting the steering coils sequentially with a 100 mA maximum current per coil. When exciting a single axial coil, the deflection was half this value with 30% higher current. A hyperintense catheter tip useful for catheter tracking was obtained by imaging with the modified GRE sequence. Clear visualization of the areas surrounding the

  20. Current steering with partial tripolar stimulation mode in cochlear implants.

    Science.gov (United States)

    Wu, Ching-Chih; Luo, Xin

    2013-04-01

    The large spread of excitation is a major cause of poor spectral resolution for cochlear implant (CI) users. Partial tripolar (pTP) mode has been proposed to reduce current spread by returning an equally distributed fraction (0.5 × σ) of current to two flanking electrodes and the rest to an extra-cochlear ground. This study tested the efficacy of incorporating current steering into pTP mode to add spectral channels. Different proportions of current [α × σ and (1 - α) × σ] were returned to the basal and apical flanking electrodes respectively to shape the electric field. Loudness and pitch perception with α from 0 to 1 in steps of 0.1 was simulated with a computational model of CI stimulation and tested on the apical, middle, and basal electrodes of six CI subjects. The highest σ allowing for full loudness growth within the implant compliance limit was chosen for each main electrode. Pitch ranking was measured between pairs of loudness-balanced steered pTP stimuli with an α interval of 0.1 at the most comfortable level. Results demonstrated that steered pTP stimuli with α around 0.5 required more current to achieve equal loudness than those with α around 0 or 1, maybe due to more focused excitation patterns. Subjects usually perceived decreasing pitches as α increased from 0 to 1, somewhat consistent with the apical shift of the center of gravity of excitation pattern in the model. Pitch discrimination was not better with α around 0.5 than with α around 0 or 1, except for some subjects and electrodes. For three subjects with better pitch discrimination, about half of the pitch ranges of two adjacent main electrodes overlapped with each other in steered pTP mode. These results suggest that current steering with focused pTP mode may improve spectral resolution and pitch perception with CIs.

  1. CCCT - NCTN Steering Committees - Pediatric and Adolescent Tumor

    Science.gov (United States)

    The Pediatric and Adolescent Solid Tumor Steering Committee addresses the design, prioritization and evaluation of concepts for large phase 2 and phase 3 clinical trials in extracranial solid tumors of children and youth.

  2. Synergistic Interactions within a Multispecies Biofilm Enhance Individual Species Protection against Grazing by a Pelagic Protozoan

    Directory of Open Access Journals (Sweden)

    Prem K. Raghupathi

    2018-01-01

    Full Text Available Biofilm formation has been shown to confer protection against grazing, but little information is available on the effect of grazing on biofilm formation and protection in multispecies consortia. With most biofilms in nature being composed of multiple bacterial species, the interactions and dynamics of a multispecies bacterial biofilm subject to grazing by a pelagic protozoan predator were investigated. To this end, a mono and multispecies biofilms of four bacterial soil isolates, namely Xanthomonas retroflexus, Stenotrophomonas rhizophila, Microbacterium oxydans and Paenibacillus amylolyticus, were constructed and subjected to grazing by the ciliate Tetrahymena pyriformis. In monocultures, grazing strongly reduced planktonic cell numbers in P. amylolyticus and S. rhizophila and also X. retroflexus. At the same time, cell numbers in the underlying biofilms increased in S. rhizophila and X. retroflexus, but not in P. amylolyticus. This may be due to the fact that while grazing enhanced biofilm formation in the former two species, no biofilm was formed by P. amylolyticus in monoculture, either with or without grazing. In four-species biofilms, biofilm formation was higher than in the best monoculture, a strong biodiversity effect that was even more pronounced in the presence of grazing. While cell numbers of X. retroflexus, S. rhizophila, and P. amylolyticus in the planktonic fraction were greatly reduced in the presence of grazers, cell numbers of all three species strongly increased in the biofilm. Our results show that synergistic interactions between the four-species were important to induce biofilm formation, and suggest that bacterial members that produce more biofilm when exposed to the grazer not only protect themselves but also supported other members which are sensitive to grazing, thereby providing a “shared grazing protection” within the four-species biofilm model. Hence, complex interactions shape the dynamics of the biofilm and

  3. Effect of day or night grazing on behaviour of swamp buffalo heifers

    Directory of Open Access Journals (Sweden)

    Somparn, P.

    2007-03-01

    Full Text Available An experiment was conducted to examine the effect of day or night grazing on behaviour by swamp buffaloes. A grazing trial was conducted over 42 days in the late rainy season, during September to November2005 at Surin Livestock Research and Breeding Center, Surin province. The experimental period was divided into two 21-day periods. Twelve 2-year-old swamp buffalo heifers were allocated to four groups, eachcontaining three heifers, with the mean group weights being as similar as possible. Each group was allowed to graze either from 06:20 to 18:00 h (daytime treatment or from 18:20 to 06:00 h (nighttime treatment infour separate paddocks, each of 5 rai, using a cross-over design. When not at pasture the animals in each group were kept in the common corral with free access to fresh drinking water and mineral blocks. Individualanimal activity was recorded by visual observation at 1-min intervals during the period at pasture. Individual groups within each period were treated as replicates. Differences between group means weretested using MIXED procedure of SAS.The buffaloes on daytime treatment spent longer (P<0.05 grazing than those on nighttime treatment (423 vs 332 min. The number of meals differed (P<0.05 between treatments, but overall mean meal durationswere similar (73 min. Buffaloes allowed to graze during daylight had a tendency (P<0.10 toward a higher bite and step rates than those grazing during the night. With the reduction in grazing activity duringthe night on nighttime treatment, the animals ruminated for longer during the period at pasture (327 and 191 min, P<0.001. Live-weight change over periods of 20 days did not differ significantly. The difference intemporal behaviour patterns between treatments indicated that animals have to adapt foraging strategies appropriate for different situations in order to maintain feed intake and subsequently production.

  4. Allelopathic cover crop prior to seeding is more important than subsequent grazing/mowing in grassland establishment

    Science.gov (United States)

    Milchunas, Daniel G.; Vandever, Mark W.; Ball, Leonard O.; Hyberg, Skip

    2011-01-01

    The effects of grazing, mowing, and type of cover crop were evaluated in a previous winter wheat–fallow cropland seeded to grassland under the Conservation Reserve Program in eastern Colorado. Prior to seeding, the fallow strips were planted to forage sorghum or wheat in alternating strips (cover crops), with no grazing, moderate to heavy grazing, and mowing (grazing treatments) superimposed 4 yr after planting and studied for 3 yr. Plots previously in wheat had more annual and exotic species than sorghum plots. Concomitantly, there were much greater abundances of perennial native grass and all native species in sorghum than wheat cropped areas. The competitive advantage gained by seeded species in sorghum plots resulted in large increases in rhizomatous western wheatgrass. Sorghum is known to be allelopathic and is used in crop agriculture rotations to suppress weeds and increase crop yields, consistent with the responses of weed and desired native species in this study. Grazing treatment had relatively minor effects on basal and canopy cover composition of annual or exotic species versus perennial native grass or native species. Although grazing treatment never was a significant main effect, it occasionally modified cover crop or year effects. Opportunistic grazing reduced exotic cheatgrass by year 3 but also decreased the native palatable western wheatgrass. Mowing was a less effective weed control practice than grazing. Vegetative basal cover and aboveground primary production varied primarily with year. Common management practices for revegetation/restoration currently use herbicides and mowing as weed control practices and restrict grazing in all stages of development. Results suggest that allelopathic cover crop selection and opportunistic grazing can be effective alternative grass establishment and weed control practices. Susceptibility, resistance, and interactions of weed and seeded species to allelopathic cover species/cultivars may be a fruitful area

  5. Effect of Grazing Intensity on Some Soil Chemical Characteristics in Gardaneh Zanburi Rangeland of Arsanjan

    Directory of Open Access Journals (Sweden)

    zeinab khademolhosseini

    2016-02-01

    Full Text Available Introduction:Changes caused by grazing on range ecosystem are generally assessed based on the soil conditions and vegetation. Livestock as one of the major elements in range land ecosystems has different effects on different parts of this ecosystem. One of these impacts is excessive livestock grazing capacity which can have different effects on soils and plants in various intensities. Materials and Methods:Gardaneh ZanbooriRangelandis located in Arsanjan in Fars province. This isanareaof mountains, hillsandplains with the maximum height of 2280 meters and minimum height of 1640 meters above sea level. Related areas were separated under three different management methods of enclosure, moderate grazing and heavy grazing. These three areas are considered as symbolic areas of grazing intensity including the reference area where no grazing intensity was observed, the key area where medium to heavy grazing was applied and critical area where heavy grazing was used. These areas were similar in all characteristics such as topography, soil type and rainfall and differed only in their grazing intensity factor. Then, soil samples were collected. Random systematic soil sampling was conducted at two horizons of 0 -15 and 15 -30 cm. Therefore, five profiles in each area (enclosure, moderate grazing and heavy grazing, a total of 15 soil profiles, were excavated and two samples were taken in each profile (one sample from each horizon. Finally, the thirty soil samples were transported to the laboratory. Samples were dried in the air laboratory and passed a two millimeter sieve after smashing. Factors such as N, P, K, OM, EC and PH were measured in each sample In the laboratory, the percentage of P was determined by the Olsen method while the percentage of K was determined using the flamephotometry method. Moreover, N was measured using the Kjeldhal method. C was measured by the Walkley and Black method. The percentage of OM was found by carbon multiplying

  6. Carcass characteristics and meat quality of Hereford sired steers born to beef-cross-dairy and Angus breeding cows.

    Science.gov (United States)

    Coleman, Lucy W; Hickson, Rebecca E; Schreurs, Nicola M; Martin, Natalia P; Kenyon, Paul R; Lopez-Villalobos, Nicolas; Morris, Stephen T

    2016-11-01

    Steers from Angus, Angus×Holstein Friesian, Angus×Holstein Friesian-Jersey and Angus×Jersey cows and a Hereford sire were measured for their carcass and meat quality characteristics. Steers from the Angus×Holstein Friesian cows had a greater final body weight and carcass weight (P<0.05). Steers from Angus×Jersey cows had the lowest carcass weight and dressing-out percentage (P<0.05). There was a greater fat depth over the rump at 12 and 18months of age for the steers from Angus cows (P<0.05) but, not at 24months of age. The steers had similar meat quality characteristics across the breed groups. Steers from Angus×Holstein Friesian and Angus×Jersey cows had a higher ratio of n6 to n3 fatty acids. Using beef-cross-dairy cows to produce steers for meat production does not impact on meat quality. Using Jersey in the breed cross reduced the carcass tissues in the live weight and the potential meat yield. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. 25 CFR 700.722 - Grazing associations.

    Science.gov (United States)

    2010-04-01

    ... recognition by the Commissioner are: (1) The members of the association must be grazing permittees and.... (d) The Commissioner may withdraw his recognition of the association whenever: (1) The majority of... constitution and bylaws. All of the association's livestock will be run under an association brand properly...

  8. Creating virtual electrodes with 2D current steering

    Science.gov (United States)

    Spencer, Thomas C.; Fallon, James B.; Shivdasani, Mohit N.

    2018-06-01

    Objective. Current steering techniques have shown promise in retinal prostheses as a way to increase the number of distinct percepts elicitable without increasing the number of implanted electrodes. Previously, it has been shown that ‘virtual’ electrodes can be created between simultaneously stimulated electrode pairs, producing unique cortical response patterns. This study investigated whether virtual electrodes could be created using 2D current steering, and whether these virtual electrodes can produce cortical responses with predictable spatial characteristics. Approach. Normally-sighted eyes of seven adult anaesthetised cats were implanted with a 42-channel electrode array in the suprachoroidal space and multi-unit neural activity was recorded from the visual cortex. Stimuli were delivered to individual physical electrodes, or electrodes grouped into triangular, rectangular, and hexagonal arrangements. Varying proportions of charge were applied to each electrode in a group to ‘steer’ current and create virtual electrodes. The centroids of cortical responses to stimulation of virtual electrodes were compared to those evoked by stimulation of single physical electrodes. Main results. Responses to stimulation of groups of up to six electrodes with equal ratios of charge on each electrode resulted in cortical activation patterns that were similar to those elicited by the central physical electrode (centroids: RM ANOVA on ranks, p  >  0.05 neural spread: one-way ANOVA on Ranks, p  >  0.05). We were also able to steer the centroid of activation towards the direction of any of the electrodes of the group by applying a greater charge to that electrode, but the movement in the centroid was not found to be significant. Significance. The results suggest that current steering is possible in two dimensions between up to at least six electrodes, indicating it may be possible to increase the number of percepts in patients without increasing the number

  9. Active Return-to-Center Control Based on Torque and Angle Sensors for Electric Power Steering Systems

    Directory of Open Access Journals (Sweden)

    Pan-Pan Du

    2018-03-01

    Full Text Available This paper presents a complete control strategy of the active return-to-center (RTC control for electric power steering (EPS systems. We first establish the mathematical model of the EPS system and analyze the source and influence of the self-aligning torque (SAT. Second, based on the feedback signals of steering column torque and steering wheel angle, we give the trigger conditions of a state switch between the steering assist state and the RTC state. In order to avoid the sudden change of the output torque for the driving motor when the state switches frequently between the steering assist state and the RTC state, we design an undisturbed state switching logic algorithm. This state switching logic algorithm ensures that the output value of the RTC controller is set to an initial value and increases in given steps up to a maximum value after entering the RTC state, and the output value of the RTC controller will reduce in given steps down to zero when exiting the RTC state. This therefore ensures smooth switch control between the two states and improves the driver’s steering feeling. Third, we design the RTC controller, which depends upon the feedback signals of the steering wheel angle and the angular velocity. In addition, the controller increases the auxiliary control function of the RTC torque based on vehicle speed. The experimental results show that the active RTC control method does not affect the basic assist characteristics, which effectively reduces the residual angle of the steering wheel at low vehicle speed and improves the RTC performance of the vehicle.

  10. Wetting of alkanes on water

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, E.; Bonn, D.; Meunier, J.; Shahidzadeh, N. [Ecole Normale Superieure, Laboratoire de Physique Statistique, 24 rue Lhomond, 75231, Cedex 05 Paris (France); Broseta, D.; Ragil, K. [Institut Francais du Petrole, 1-4 avenue de Bois Preau, 92852 Rueil-Malmaison Cedex (France); Dobbs, H.; Indekeu, J.O. [Katholieke Universiteit Leuven, Laboratorium voor Vaste-Stoffysica en Magnetisme, B-3001 Leuven (Belgium)

    2002-04-01

    The wetting behavior of oil on water (or brine) has important consequences for the transport properties of oil in water-containing porous reservoirs, and consequently for oil recovery. The equilibrium wetting behavior of model oils composed of pure alkanes or alkane mixtures on brine is reviewed in this paper. Intermediate between the partial wetting state, in which oil lenses coexist on water with a thin film of adsorbed alkane molecules, and the complete wetting state, in which a macroscopically thick oil layer covers the water, these systems display a third, novel wetting state, in which oil lenses coexist with a mesoscopic (a few-nanometers-thick) oil film. The nature and location of the transitions between these wetting regimes depend on oil and brine compositions, temperature and pressure.

  11. Adaptive Sliding Mode Control Method Based on Nonlinear Integral Sliding Surface for Agricultural Vehicle Steering Control

    Directory of Open Access Journals (Sweden)

    Taochang Li

    2014-01-01

    Full Text Available Automatic steering control is the key factor and essential condition in the realization of the automatic navigation control of agricultural vehicles. In order to get satisfactory steering control performance, an adaptive sliding mode control method based on a nonlinear integral sliding surface is proposed in this paper for agricultural vehicle steering control. First, the vehicle steering system is modeled as a second-order mathematic model; the system uncertainties and unmodeled dynamics as well as the external disturbances are regarded as the equivalent disturbances satisfying a certain boundary. Second, a transient process of the desired system response is constructed in each navigation control period. Based on the transient process, a nonlinear integral sliding surface is designed. Then the corresponding sliding mode control law is proposed to guarantee the fast response characteristics with no overshoot in the closed-loop steering control system. Meanwhile, the switching gain of sliding mode control is adaptively adjusted to alleviate the control input chattering by using the fuzzy control method. Finally, the effectiveness and the superiority of the proposed method are verified by a series of simulation and actual steering control experiments.

  12. Microbial quality of soil from the Pampa biome in response to different grazing pressures

    Directory of Open Access Journals (Sweden)

    Rafael S. Vargas

    2015-06-01

    Full Text Available The aim of this study was to evaluate the impact of different grazing pressures on the activity and diversity of soil bacteria. We performed a long-term experiment in Eldorado do Sul, southern Brazil, that assessed three levels of grazing pressure: high pressure (HP, with 4% herbage allowance (HA, moderate pressure (MP, with 12% HA, and low pressure (LP, with 16% HA. Two reference areas were also assessed, one of never-grazed native vegetation (NG and another of regenerated vegetation after two years of grazing (RG. Soil samples were evaluated for microbial biomass and enzymatic (β-glucosidase, arylsulfatase and urease activities. The structure of the bacterial community and the population of diazotrophic bacteria were evaluated by RFLP of the 16S rRNA and nifH genes, respectively. The diversity of diazotrophic bacteria was assessed by partial sequencing of the 16S rDNA gene. The presence of grazing animals increased soil microbial biomass in MP and HP. The structures of the bacterial community and the populations of diazotrophic bacteria were altered by the different grazing managements, with a greater diversity of diazotrophic bacteria in the LP treatment. Based on the characteristics evaluated, the MP treatment was the most appropriate for animal production and conservation of the Pampa biome.

  13. Detailed field test of yaw-based wake steering

    DEFF Research Database (Denmark)

    Fleming, P.; Churchfield, M.; Scholbrock, A.

    2016-01-01

    production. In the first phase, a nacelle-mounted scanning lidar was used to verify wake deflection of a misaligned turbine and calibrate wake deflection models. In the second phase, these models were used within a yaw controller to achieve a desired wake deflection. This paper details the experimental......This paper describes a detailed field-test campaign to investigate yaw-based wake steering. In yaw-based wake steering, an upstream turbine intentionally misaligns its yaw with respect to the inflow to deflect its wake away from a downstream turbine, with the goal of increasing total power...... design and setup. All data collected as part of this field experiment will be archived and made available to the public via the U.S. Department of Energy’s Atmosphere to Electrons Data Archive and Portal....

  14. Water Quality Conditions Associated with Cattle Grazing and Recreation on National Forest Lands.

    Directory of Open Access Journals (Sweden)

    Leslie M Roche

    Full Text Available There is substantial concern that microbial and nutrient pollution by cattle on public lands degrades water quality, threatening human and ecological health. Given the importance of clean water on multiple-use landscapes, additional research is required to document and examine potential water quality issues across common resource use activities. During the 2011 grazing-recreation season, we conducted a cross sectional survey of water quality conditions associated with cattle grazing and/or recreation on 12 public lands grazing allotments in California. Our specific study objectives were to 1 quantify fecal indicator bacteria (FIB; fecal coliform and E. coli, total nitrogen, nitrate, ammonium, total phosphorus, and soluble-reactive phosphorus concentrations in surface waters; 2 compare results to a water quality regulatory benchmarks, b recommended maximum nutrient concentrations, and c estimates of nutrient background concentrations; and 3 examine relationships between water quality, environmental conditions, cattle grazing, and recreation. Nutrient concentrations observed throughout the grazing-recreation season were at least one order of magnitude below levels of ecological concern, and were similar to U.S. Environmental Protection Agency (USEPA estimates for background water quality conditions in the region. The relative percentage of FIB regulatory benchmark exceedances widely varied under individual regional and national water quality standards. Relative to USEPA's national E. coli FIB benchmarks-the most contemporary and relevant standards for this study-over 90% of the 743 samples collected were below recommended criteria values. FIB concentrations were significantly greater when stream flow was low or stagnant, water was turbid, and when cattle were actively observed at sampling. Recreation sites had the lowest mean FIB, total nitrogen, and soluble-reactive phosphorus concentrations, and there were no significant differences in FIB and

  15. Nickel, Cobalt, Chromium and Copper in agricultural and grazing land soils of Europe

    Science.gov (United States)

    Albanese, Stefano; Sadeghi, Martiya; De Vivo, Benedetto; Lima, Annamaria; Cicchella, Domenico; Dinelli, Enrico

    2014-05-01

    In the framework of the GEMAS (Geochemical Mapping of Agricultural and Grazing Land Soils) project, concentrations of Ni, Co, Cu and Cr were determined for the whole available dataset (2218 samples of agricultural soil and 2127 samples of grazing land soil) covering a total area of 5.6 million sq km all over Europe. The distribution pattern of Ni in the European soils (both agricultural and grazing land soils) shows the highest concentrations in correspondence with the Mediterranean area (especially in Greece, the Balcan Peninsula and NW Italy) with average values generally ranging between 40 mg/kg and 140 mg/kg and anomalous areas characterized by peaks higher than 2400 mg/kg. Concentrations between 10 mg/kg and 40 mg/kg characterize Continental Europe north of Alps and, partly, the Scandinavian countries. Lower concentrations (agricultural and grazing land soils. The maximum concentration peaks of Cobalt and Cr rise up to respectively 126 mg/kg and 696 mg/kg in agricultural soils and up to 255 mg/kg and 577 mg/kg in grazing land soils. Copper distribution in the soils collected across Europe, although has a general correspondence with the patterns of Ni, Co, Cr, shows some peculiarities. Specifically, Cu is characterized by high concentration values (up to 395 mg/kg in agricultural soils and 373 mg/kg in Grazing land soils) also in correspondence with the Roman Comagmatic Province and the south western coast of France characterized by a wide spread of vineyards.

  16. The effects of grazing intensity on soil processes in a Mediterranean protected area.

    Science.gov (United States)

    Panayiotou, Evaggelia; Dimou, Maria; Monokrousos, Nikolaos

    2017-08-08

    We investigated the temporal and among-site differentiation of soil functionality properties in fields under different grazing intensities (heavy and light) and compared them to those found in their adjacent hedgerows, consisting either of wooden shrubs (Rubus canescens) or of high trees (Populus sp.), during the cold and humid seasons of the year. We hypothesized that greater intensity of grazing would result in higher degradation of the soil system. The grazing factor had a significant effect on soil organic C and N, microbial biomass C, microbial biomass N, microbial activity, and β-glucosidase, while acid phosphatase and urease activity were not found to differ significantly among the management systems. The intensity of grazing affected mostly the chemical properties of soil (organic C and N) and altered significantly the composition of the soil microbial community, as lower C:N ratio of the microbial biomass indicates the dominance of bacteria over fungi in the heavily grazed fields. All estimated biological variables presented higher values in the humid period, although the pattern of differentiation was similar at both sampling times, revealing that site-specific variations were more pronounced than the time-specific ones. Our results indicate that not all C, N, and P dynamics were equally affected by grazing. Management plans applied to pastures, in order to improve soil quality properties and accelerate passive reforestation, should aim at the improvement of soil parameters related primarily to C and secondly to N cycle.

  17. Sentinel model for influenza A virus monitoring in free-grazing ducks in Thailand.

    Science.gov (United States)

    Boonyapisitsopa, Supanat; Chaiyawong, Supassama; Nonthabenjawan, Nutthawan; Jairak, Waleemas; Prakairungnamthip, Duangduean; Bunpapong, Napawan; Amonsin, Alongkorn

    2016-01-01

    Influenza A virus (IAV) can cause influenza in birds and mammals. In Thailand, free-grazing ducks are known IAV reservoirs and can spread viruses through frequent movements in habitats they share with wild birds. In this study, the sentinel model for IAV monitoring was conducted over 4 months in two free-grazing duck flocks. IAV subtypes H4N6 (n=1) and H3N8 (n=5) were isolated from sentinel ducks at the ages of 13 and 15 weeks. Clinical signs of depression and ocular discharge were observed in the infected ducks. Phylogenetic analysis and genetic characterization of the isolated IAVs indicated that all Thai IAVs were clustered in the Eurasian lineage and pose low pathogenic avian influenza characteristics. Serological analysis found that antibodies against IAVs could be detected in the ducks since 9-weeks-old. In summary, our results indicate that the sentinel model can be used for IAV monitoring in free-grazing duck flocks. Since free-grazing ducks are potential reservoirs and transmitters of IAVs, routine IAV surveillance in free-grazing duck flocks can be beneficial for influenza prevention and control strategies. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Grazing incidence optics; Proceedings of the Meeting, Orlando, FL, Apr. 3, 4, 1986

    Science.gov (United States)

    Osantowski, John F. (Editor); Van Speybroeck, Leon (Editor)

    1986-01-01

    Papers are presented on the diffraction-limited performance of grazing incidence optical systems; transverse ray aberrations of Wolter type 1 telescopes; hybrid X-ray telescope systems; surface characterization of grazing incidence optics in the extreme UV and X-ray regions; and the surface roughness properties of synchrotron radiation optics. Topics discussed include the simulation of free-abrasive grinding of grazing incidence mirrors with vertical-honing and flexible blades; mirrors for the Extreme Ultraviolet Explorer; the design and development of conical X-ray imaging mirrors; thermal loading considerations for synchrotron radiation mirrors; and grazing incidence optics for synchrotron radiation insertion-device beams. Consideration is given to the interpretation of glancing incidence scattering measurements; damage processes in short wavelength coated FEL optics; the replication of grain incidence optics; and the assembly and alignment of the Technology Mirror Assembly.

  19. Grazing patterns on signalgrass pasture according to location of cattle feces

    Directory of Open Access Journals (Sweden)

    Manoel Eduardo Rozalino Santos

    2012-04-01

    Full Text Available This study was conducted to evaluate the defoliation patterns on B. decumbens cv. Basilisk (signalgrass tiller as a function of influence of feces deposited naturally by cattle. The signalgrass was managed with an average height of 25 cm, under continuous stocking and variable stocking rate. Interval and intensity of defoliation, grazing efficiency and forage loss were evaluated in two sites on pasture - one close and the other distant from feces. The completely randomized block design with three replications was adopted. The defoliation rate of the pasture site close to feces was 40% lower than at that distant from feces. This response pattern was similar to defoliation intensity of leaf blade. The leaf blade of the tiller close to feces also achieved lower de foliation (1.64 than that in the tiller distant from feces (3.97. The relative number of grazed leaf per tiller in the tillers distant from feces was approximately 185% higher than those close to feces. The grazing efficiency was lower in the local close to feces compared with that distant, unlike forage loss. The natural deposition of feces by cattle modifies the grazing and use patterns of B. decumbens under continuous stocking.

  20. Concentrate Supplement Modifies the Feeding Behavior of Simmental Cows Grazing in Two High Mountain Pastures

    Directory of Open Access Journals (Sweden)

    Alberto Romanzin

    2018-05-01

    Full Text Available During grazing on Alpine pastures, the use of concentrates in dairy cows’ diet leads to a reduction of the environmental sustainability of farms, and influences the selective pressure on some plant species. In order to minimize the use of concentrates, it is imperative to obtain data on the grazing behavior of cows. The aim of this study was to assess the effect of concentrate levels on the behavior of dairy cows during grazing. One hundred and ten lactating Italian Simmental cows, that sequentially grazed two pastures characterized by Poion alpinae (Poion and Seslerion caeruleae (Seslerion alliance, were considered. For each pasture, eight cows were selected and assigned to two groups: High and Low, supplemented with 4 kg/head/d, and 1 kg/head/d of concentrate respectively. Cows were equipped with a noseband pressure sensor and a pedometer (RumiWatch system, ITIN-HOCH GmbH to assess grazing, ruminating, and walking behavior. In addition, the plant selection of the animals was assessed. On Poion, increased supplement intake caused a more intense selection of legumes, without affecting feeding and walking times. On Seslerion, grazing time was higher in Low than High. Grazing management in alpine region must take into account the great variability of pastures that largely differ from a floristic and nutritional point of view.

  1. Effects of livestock grazing on neotropical migratory landbirds in western North America

    Science.gov (United States)

    Carl E. Bock; Victoria A. Saab; Terrell D. Rich; David S. Dobkin

    1993-01-01

    Livestock grazing is a widespread and important influence on neotropical migratory birds in four major ecosystems in western North America: grasslands of the Great Plains and Southwest, riparian woodlands, Intermountain shrubsteppe, and open coniferous forests. We have reviewed available literature on avian responses to grazing in these habitats. Among 35 plains...

  2. Sierra Nevada grasslands: interactions between livestock grazing and ecosystem structure and function

    Science.gov (United States)

    Barbara H. Allen-Diaz

    2004-01-01

    Livestock grazing plays an integral role in the grass-dominated ecosystems of the Sierra Nevada. Grazing has been asserted to influence such key ecological characteristics as water quality, net primary productivity, nutrient cycling, plant and animal diversity, wildlife habitat availability, and oak regeneration (Belsky and others 1999, Kauffmann and Krueger 1984)....

  3. Adiabatic photo-steering theory in topological insulators

    Science.gov (United States)

    Inoue, Jun-ichi

    2014-12-01

    Feasible external control of material properties is a crucial issue in condensed matter physics. A new approach to achieving this aim, named adiabatic photo-steering, is reviewed. The core principle of this scheme is that several material constants are effectively turned into externally tunable variables by irradiation of monochromatic laser light. Two-dimensional topological insulators are selected as the optimal systems that exhibit a prominent change in their properties following the application of this method. Two specific examples of photo-steered quantum phenomena, which reflect topological aspects of the electronic systems at hand, are presented. One is the integer quantum Hall effect described by the Haldane model, and the other is the quantum spin Hall effect described by the Kane-Mele model. The topological quantities associated with these phenomena are the conventional Chern number and spin Chern number, respectively. A recent interesting idea, time-reversal symmetry breaking via a temporary periodic external stimulation, is also discussed.

  4. Adiabatic photo-steering theory in topological insulators

    International Nuclear Information System (INIS)

    Inoue, Jun-ichi

    2014-01-01

    Feasible external control of material properties is a crucial issue in condensed matter physics. A new approach to achieving this aim, named adiabatic photo-steering, is reviewed. The core principle of this scheme is that several material constants are effectively turned into externally tunable variables by irradiation of monochromatic laser light. Two-dimensional topological insulators are selected as the optimal systems that exhibit a prominent change in their properties following the application of this method. Two specific examples of photo-steered quantum phenomena, which reflect topological aspects of the electronic systems at hand, are presented. One is the integer quantum Hall effect described by the Haldane model, and the other is the quantum spin Hall effect described by the Kane–Mele model. The topological quantities associated with these phenomena are the conventional Chern number and spin Chern number, respectively. A recent interesting idea, time-reversal symmetry breaking via a temporary periodic external stimulation, is also discussed. (focus issue review)

  5. [Soil seed bank in Keerqin meadow grassland under grazing and harvesting].

    Science.gov (United States)

    Jiang, Deming; Li, Rongping; Liu, Zhimin; Yan, Qiaoling

    2004-10-01

    This study on the size and composition of seed bank and its relationship with vegetation showed in Keerqin meadow grassland, the density of soil seed bank was 6158 +/- 1647 grains x m(-2) under grazing and 8312 +/- 2540 grains m(-2) under harvesting. Under grazing, the seed bank was mainly composed of some dwarf and short-life annuals. The seeds of the annuals and biennials accounted for 81.66% of the seeds in seed bank. The four species with largest proportion of seed bank were Chloris virgata, Chenopodium glaucum, Digitaria cilliaris and Setaria viridis, and the proportions were 38.55%, 15.42%, 14.95%, and 9.83%, respectively. The density of perennials in soil seed bank was 1129 +/- 302 grains x m(-2). Under harvesting, the seeds of annuals and biennials accounted for 68.08% of the seed in seed bank, and the proportion of Setaria viridis was 52.7%. In the harvesting meadow grassland, the seed density of perennials was 2653 +/- 811 grains x m(-2). There was no significant correlation between the seed density in soil and the vegetation under grazing, but a significant correlation between the seed density in soil and the species abundance of vegetation under harvesting (r = 0.76, P < 0.01). The index of Shannon-Wiener and richness of grazing meadow grassland were 2.96 and 2.98, respectively, distinctly smaller than 3.10 and 5.09 of harvesting meadow, which showed that free grazing made the diversity of seed bank decrease easily.

  6. Interactions of Grazing History, Cattle Removal and Time since Rain Drive Divergent Short-Term Responses by Desert Biota

    Science.gov (United States)

    Frank, Anke S. K.; Dickman, Chris R.; Wardle, Glenda M.; Greenville, Aaron C.

    2013-01-01

    Arid grasslands are used worldwide for grazing by domestic livestock, generating debate about how this pastoral enterprise may influence native desert biota. One approach to resolving this question is to experimentally reduce livestock numbers and measure the effects. However, a key challenge in doing this is that historical grazing impacts are likely to be cumulative and may therefore confound comparisons of the short-term responses of desert biota to changes in stocking levels. Arid areas are also subject to infrequent flooding rainfalls that drive productivity and dramatically alter abundances of flora and fauna. We took advantage of an opportunity to study the recent effects of a property-scale cattle removal on two properties with similarly varied grazing histories in central Australia. Following the removal of cattle in 2006 and before and after a significant rainfall event at the beginning of 2007, we sampled vegetation and small vertebrates on eight occasions until October 2008. Our results revealed significant interactions of time of survey with both grazing history and grazing removal for vascular plants, small mammals and reptiles. The mammals exhibited a three-way interaction of time, grazing history and grazing removal, thus highlighting the importance of careful sampling designs and timing for future monitoring. The strongest response to the cessation of grazing after two years was depressed reproductive output of plants in areas where cattle continued to graze. Our results confirm that neither vegetation nor small vertebrates necessarily respond immediately to the removal of livestock, but that rainfall events and cumulative grazing history are key determinants of floral and faunal performance in grassland landscapes with low and variable rainfall. We suggest that improved assessments could be made of the health of arid grazing environments if long-term monitoring were implemented to track the complex interactions that influence how native biota

  7. Mechanical design aspects of a "Long-Waveguide" version of the remote steering ECRH upper port launcher for ITER

    NARCIS (Netherlands)

    Ronden, D. M. S.; van den Berg, M.; Bongers, W. A.; Elzendoorn, B. S. Q.; M. F. Graswinckel,; Lamers, B.; Van Nigtevecht, K.; Verhoeven, A. G. A.; Henderson, M. A.

    2008-01-01

    The current status of the mechanical design of the remote steering electron cyclotron resonance heating upper port launching system for ITER is presented. Although an alternative front steering launcher has now been selected as the reference design for ITER, the development of a remote steering

  8. [Relation between species distribution of plant community and soil factors under grazing in alpine meadow].

    Science.gov (United States)

    Niu, Yu Jie; Yang, Si Wei; Wang, Gui Zhen; Liu, Li; Du, Guo Zhen; Hua, Li Min

    2017-12-01

    The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different grazing intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the grazing caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low grazing intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of grazing intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against grazing intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration rate and large aggregate index were significantly changed with grazing intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under grazing. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest rate of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on grazed alpine meadow.

  9. Spatial Distribution of Nitrogen on Grazed Karst Landscapes

    Directory of Open Access Journals (Sweden)

    Douglas G. Boyer

    2001-01-01

    Full Text Available The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian region. Karst areas comprise about 18% of the region’s land area. An estimated one-third of the region’s farms, cattle, and agricultural market value are located on karst terrain. Mean nitrate concentrations in several karst springs in southeastern West Virginia exhibit a strong linear relationship with the percentage of agriculture land cover. Development of best management practices for efficient nitrogen (N use and reduction of outflow of N to water from karst areas requires knowledge about N dynamics on those landscapes. Water extractable NO3-N and NH4-N were measured along transects at four soil depths in two grazed sinkholes and one wooded sinkhole. Distribution of soil NO3-N and NH4-N were related to frequency of animal presence and to topographic and hydrologic redistribution of soil and fecal matter in the grazed sinkholes. Karst pastures are characterized by under drainage and funneling of water and contaminants to the shallow aquifer. Control of NO3-N leaching from karst pasture may depend on management strategies that change livestock grazing behavior in sinkholes and reduce the opportunity for water and contaminants to quickly reach sinkhole drains.

  10. Speed-constrained three-axes attitude control using kinematic steering

    Science.gov (United States)

    Schaub, Hanspeter; Piggott, Scott

    2018-06-01

    Spacecraft attitude control solutions typically are torque-level algorithms that simultaneously control both the attitude and angular velocity tracking errors. In contrast, robotic control solutions are kinematic steering commands where rates are treated as the control variable, and a servo-tracking control subsystem is present to achieve the desired control rates. In this paper kinematic attitude steering controls are developed where an outer control loop establishes a desired angular response history to a tracking error, and an inner control loop tracks the commanded body angular rates. The overall stability relies on the separation principle of the inner and outer control loops which must have sufficiently different response time scales. The benefit is that the outer steering law response can be readily shaped to a desired behavior, such as limiting the approach angular velocity when a large tracking error is corrected. A Modified Rodrigues Parameters implementation is presented that smoothly saturates the speed response. A robust nonlinear body rate servo loop is developed which includes integral feedback. This approach provides a convenient modular framework that makes it simple to interchange outer and inner control loops to readily setup new control implementations. Numerical simulations illustrate the expected performance for an aggressive reorientation maneuver subject to an unknown external torque.

  11. Farm-level risk factors for Fasciola hepatica infection in Danish dairy cattle as evaluated by two diagnostic methods

    DEFF Research Database (Denmark)

    Takeuchi-Storm, Nao; Denwood, Matthew; Hansen, Tina Vicky Alstrup

    2017-01-01

    ) as a tool for diagnosis in Danish dairy cattle farms was assessed. This case-control study aimed to identify farm-level risk factors for fasciolosis in Danish dairy farms (> 50 animals slaughtered in 2013) using two diagnostic methods: recordings of liver condemnation at slaughter, and farm-level Fasciola...... on wet pastures, dry cows grazing on wet pastures, herd size, breed and concurrent beef cattle production were identified as risk factors associated with being classified as a case farm. With the categorised BTM ELISA result as the response variable, heifers grazing on wet pastures, dry cows grazing...... on wet pastures, and purchase of cows were identified as risk factors. Within the case and control groups, 74.8 and 12.7% of farms were positive for fasciolosis on BTM ELISA, respectively. The differences are likely to be related to the detection limit of the farm-level prevalence by the BTM ELISA test...

  12. Landscape management of fire and grazing regimes alters the fine-scale habitat utilisation by feral cats.

    Science.gov (United States)

    McGregor, Hugh W; Legge, Sarah; Jones, Menna E; Johnson, Christopher N

    2014-01-01

    Intensification of fires and grazing by large herbivores has caused population declines in small vertebrates in many ecosystems worldwide. Impacts are rarely direct, and usually appear driven via indirect pathways, such as changes to predator-prey dynamics. Fire events and grazing may improve habitat and/or hunting success for the predators of small mammals, however, such impacts have not been documented. To test for such an interaction, we investigated fine-scale habitat selection by feral cats in relation to fire, grazing and small-mammal abundance. Our study was conducted in north-western Australia, where small mammal populations are sensitive to changes in fire and grazing management. We deployed GPS collars on 32 cats in landscapes with contrasting fire and grazing treatments. Fine-scale habitat selection was determined using discrete choice modelling of cat movements. We found that cats selected areas with open grass cover, including heavily-grazed areas. They strongly selected for areas recently burnt by intense fires, but only in habitats that typically support high abundance of small mammals. Intense fires and grazing by introduced herbivores created conditions that are favoured by cats, probably because their hunting success is improved. This mechanism could explain why, in northern Australia, impacts of feral cats on small mammals might have increased. Our results suggest the impact of feral cats could be reduced in most ecosystems by maximising grass cover, minimising the incidence of intense fires, and reducing grazing by large herbivores.

  13. Landscape management of fire and grazing regimes alters the fine-scale habitat utilisation by feral cats.

    Directory of Open Access Journals (Sweden)

    Hugh W McGregor

    Full Text Available Intensification of fires and grazing by large herbivores has caused population declines in small vertebrates in many ecosystems worldwide. Impacts are rarely direct, and usually appear driven via indirect pathways, such as changes to predator-prey dynamics. Fire events and grazing may improve habitat and/or hunting success for the predators of small mammals, however, such impacts have not been documented. To test for such an interaction, we investigated fine-scale habitat selection by feral cats in relation to fire, grazing and small-mammal abundance. Our study was conducted in north-western Australia, where small mammal populations are sensitive to changes in fire and grazing management. We deployed GPS collars on 32 cats in landscapes with contrasting fire and grazing treatments. Fine-scale habitat selection was determined using discrete choice modelling of cat movements. We found that cats selected areas with open grass cover, including heavily-grazed areas. They strongly selected for areas recently burnt by intense fires, but only in habitats that typically support high abundance of small mammals. Intense fires and grazing by introduced herbivores created conditions that are favoured by cats, probably because their hunting success is improved. This mechanism could explain why, in northern Australia, impacts of feral cats on small mammals might have increased. Our results suggest the impact of feral cats could be reduced in most ecosystems by maximising grass cover, minimising the incidence of intense fires, and reducing grazing by large herbivores.

  14. Automated steering systems applied to complex horizontal well in South Italy

    Energy Technology Data Exchange (ETDEWEB)

    Calderoni, A.; Ligrone, A.; Trampini, A. [ENI AGIP (Italy); Oppelt, J.; Gauld, S. [Baker Hughes INTEQ (United States)

    1998-12-31

    A new drilling system that not only improved the quality of the borehole trajectory, but also resulted in significant savings in capital cost is described. The new concept in drilling is the result of a joint development between a major oil company and an oilfield service provider. Through providing a breakthrough technology in directional steering systems the accuracy of the borehole steering has been substantially improved. The new concept involves the use of a straight hole drilling system (SDD) in the upper hole section, in combination with the rotary steering system, AutoTrak, in the 8.5 inch hole size. By synergistically using the new automated tools, the well was drilled much more efficiently than offset wells, producing substantial time savings, a smoother trajectory and less friction. Details of the different automated directional drilling systems that were used together in a well for the first time at Monte Enoc 9 in South Italy are described. 2 refs., 3 tabs., 9 figs.

  15. A Car-Steering Model Based on an Adaptive Neuro-Fuzzy Controller

    Science.gov (United States)

    Amor, Mohamed Anis Ben; Oda, Takeshi; Watanabe, Shigeyoshi

    This paper is concerned with the development of a car-steering model for traffic simulation. Our focus in this paper is to propose a model of the steering behavior of a human driver for different driving scenarios. These scenarios are modeled in a unified framework using the idea of target position. The proposed approach deals with the driver’s approximation and decision-making mechanisms in tracking a target position by means of fuzzy set theory. The main novelty in this paper lies in the development of a learning algorithm that has the intention to imitate the driver’s self-learning from his driving experience and to mimic his maneuvers on the steering wheel, using linear networks as local approximators in the corresponding fuzzy areas. Results obtained from the simulation of an obstacle avoidance scenario show the capability of the model to carry out a human-like behavior with emphasis on learned skills.

  16. Grazing effects on ecosystem CO2 fluxes differ among temperate steppe types in Eurasia.

    Science.gov (United States)

    Hou, Longyu; Liu, Yan; Du, Jiancai; Wang, Mingya; Wang, Hui; Mao, Peisheng

    2016-07-01

    Grassland ecosystems play a critical role in regulating CO2 fluxes into and out of the Earth's surface. Whereas previous studies have often addressed single fluxes of CO2 separately, few have addressed the relation among and controls of multiple CO2 sub-fluxes simultaneously. In this study, we examined the relation among and controls of individual CO2 fluxes (i.e., GEP, NEP, SR, ER, CR) in three contrasting temperate steppes of north China, as affected by livestock grazing. Our findings show that climatic controls of the seasonal patterns in CO2 fluxes were both individual flux- and steppe type-specific, with significant grazing impacts observed for canopy respiration only. In contrast, climatic controls of the annual patterns were only individual flux-specific, with minor grazing impacts on the individual fluxes. Grazing significantly reduced the mean annual soil respiration rate in the typical and desert steppes, but significantly enhanced both soil and canopy respiration in the meadow steppe. Our study suggests that a reassessment of the role of livestock grazing in regulating GHG exchanges is imperative in future studies.

  17. Composition of late summer diet by semi-domesticated reindeer in different grazing conditions in northernmost Finland

    Directory of Open Access Journals (Sweden)

    Pauline Bezard

    2015-09-01

    Full Text Available This study aims to investigate the diet composition of semi-domesticated reindeer (Rangifer tarandus tarandus in late summer in different kinds of grazing conditions in northernmost Finland. The composition of diet by reindeer was determined on the grounds of microhistological analysis of feces samples collected in early August in different seasonal grazing areas (winter or summer/year-round grazing areas in three reindeer management districts. Although the proportion of different plant groups varied between the studied districts, the quantified group of ground lichens (which also contained small amounts of mushrooms was the most abundant, varying from 33.0 to 46.4% in the analyzed samples. In general, there were significant differences in the proportions of lichen between districts, but not between grazing areas. The proportion of lichen in samples increased significantly when the amount of lichen pasture around a sample site increased. The proportion of dwarf shrubs and leaves in samples varied from 24.9 to 37.9% and differed significantly between districts, but not between grazing areas. In the same way, the proportion of graminoids varied between 20.9 and 36.2% and differed significantly between districts and also between grazing areas. Higher amounts of graminoids in feces were observed in summer/year-round grazing areas than in winter grazing areas. Finally, the proportion of bryophytes varied between 2.9 and 6.5% and was significantly different between districts, but not between grazing areas. An increase in old and mature coniferous forest around a sample site significantly increased the amounts of bryophytes in samples. The results indicate that reindeer adapt their summer diet composition according to the availability of food plants. The results also show that when reindeer are allowed to select their summer ranges freely, reindeer tend to use lichen pastures intensively also during summer, which causes a considerable reduction in

  18. Ka-Band Electronically Steered CubeSat Antenna, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Kymeta Government Solutions (KGS) designed, analyzed, built, tested, and delivered a small, lightweight, low-cost, low-power electronically steered Ka-band prototype...

  19. Design Optimization of Steering Mechanisms for Articulated Off-Road Vehicles Based on Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Chen Zhou

    2018-02-01

    Full Text Available Two cylinders arranged symmetrically on a frame have become a major form of steering mechanism for articulated off-road vehicles (AORVs. However, the differences of stroke and arm lead to pressure fluctuation, vibration noise, and a waste of torque. In this paper, the differences of stroke and arm are reduced based on a genetic algorithm (GA. First, the mathematical model of the steering mechanism is put forward. Then, the difference of stroke and arm are optimized using a GA. Finally, a FW50GLwheel loader is used as an example to demonstrate the proposed GA-based optimization method, and its effectiveness is verified by means of automatic dynamic analysis of mechanical systems (ADAMS. The stroke difference of the steering hydraulic cylinders was reduced by 92% and the arm difference reached a decrease of 78% through GA optimization, in comparison with unoptimized structures. The simulation result shows that the steering mechanism optimized by GA behaved better than by previous methods.

  20. Evaluation of four steering wheels to determine driver hand placement in a static environment.

    Science.gov (United States)

    Mossey, Mary E; Xi, Yubin; McConomy, Shayne K; Brooks, Johnell O; Rosopa, Patrick J; Venhovens, Paul J

    2014-07-01

    While much research exists on occupant packaging both proprietary and in the literature, more detailed research regarding user preferences for subjective ratings of steering wheel designs is sparse in published literature. This study aimed to explore the driver interactions with production steering wheels in four vehicles by using anthropometric data, driver hand placement, and driver grip design preferences for Generation-Y and Baby Boomers. In this study, participants selected their preferred grip diameter, responded to a series of questions about the steering wheel grip as they sat in four vehicles, and rank ordered their preferred grip design. Thirty-two male participants (16 Baby Boomers between ages 47 and 65 and 16 Generation-Y between ages 18 and 29) participated in the study. Drivers demonstrated different gripping behavior between vehicles and between groups. Recommendations for future work in steering wheel grip design and naturalistic driver hand positioning are discussed. Copyright © 2014. Published by Elsevier Ltd.

  1. Biological fire prevention method: Evaluating the effects of goat grazing on the fire-prone mediterranean scrub

    Energy Technology Data Exchange (ETDEWEB)

    Mancilla-Leyton, J. M.; Martin Vicente, A.

    2012-11-01

    The effect of goat grazing on the shrubby under story of a pine forest in Donana Natural Park was evaluated using non-destructive measures of vegetation volume over a period of twenty-four months. After establishing grazing exclusion fenced plots 350 adult Payoyas goats were introduced. Vegetation was sampled before the introduction of goats and afterwards twice a year, using the point intercept method and thereby obtaining data of height, frequency, cover and biovolume of species. After two years the total biovolume of the vegetation of the un grazed area had increased significantly by 32.9%, while at grazed area, vegetation bio volume decreased significantly by 23.1%, leading to a significant decrease in mean height of the species. Although the number of species remained unchanged throughout the study, significant changes in their relative abundance were found in grazed area. The different responses of scrub species to grazing can be used as a tool to control species sensitive to grazing in shrubby forested areas. Significant reduction of total bio volume due to a reduction in vegetation height will help to reduce fire risk, thus contributing to the conservation of Mediterranean woodlands and forests while also fulfilling an important role in the economic and social lives of the rural population of Mediterranean countries. (Author) 15 refs.

  2. Performance of Angus and Brangus cow-calf pairs grazing Alicia bermudagrass and common bermudagrass-dallisgrass pastures.

    Science.gov (United States)

    Wyatt, W E; Gates, R N; Blouin, D C; Saxton, A M; Nelson, B D

    1997-07-01

    This research was designed to examine genotype x environment interactions in cow-calf growth performance of grazing animals. Angus and Brangus cow-calf pairs (minimum of six per breed) were allowed to rotationally graze (14-d intervals) treatment pastures from approximately May through early October in each of 2 yr. Treatment pastures contained relatively pure stands of Alicia bermudagrass (AP) or a mixed stand of common bermudagrass and dallisgrass (CDP). Forage allowance was equalized, using "put-and-take" cow-calf pairs, among forage and breed types at the initiation of each 14-d grazing interval. Forage samples were obtained in each paddock at the initiation of each grazing interval. Forage CP concentration was greater (P < .05; 13.5 vs 11.6%) and NDF concentration was less (P < .05; 63.8 vs 70.6%) for CDP than for AP. Daily weight loss was similar for Angus and Brangus cows, but it was greater (P < .05) for cows grazing AP than for cows grazing CDP. Calf ADG during the grazing season was 35% greater (P < .05) for CDP than for AP pastures and was 23% greater (P < .01) for Brangus than for Angus calves. Relative performance of Angus and Brangus cow-calf pairs was consistent between forages; no breed x forage interactions were observed.

  3. The role of grazing land on the buffalo population dynamics in Brebes regency

    Science.gov (United States)

    Sumanto

    2017-04-01

    Brebes District is one of the centre of grazing buffalo in Indonesia that involve thousands of rearers usually kept as a family savings. This paper highlighted the availability of land and the role of the grazing land for the durability of the maintenance of buffalo in Brebes Regency. The information obtained is from interviewed the livestock facilitators in the sub-district (primary data) and from statistic of agriculture in Brebes Regency 2014 (secondary data). Generally the buffalo kept semi-intensively and commonly the buffaloes graze in the fields that are not used from morning until evening and during nights buffaloes are placed in the stalls. Rearers chose the semi-intensive system in rearing the buffalo because it is considered easy to manage and they do not need to provide fresh money to prepare the roughage for feed, because commonly the grazing buffalo are shepherd by herdman that will receive buffalo as their payment. The population density is very high (1.056 heads/km2), the buffalo ownership is between 2-4 head/households; generally the location of the grazing land is in the forest, rice fields fallow, and sleeping land, and estimated that greenfeed stock is still available abunandtly, on the other hand the urban land is less capacity of feed. The spread of buffalo is only in 125 villages from 297 villages in Brebes. The acceptance of buffalo business is around IDR 3.5 million to IDR 7.5 million/family/year. The availability of grazing land strongly influence the maintaining of buffalo farming by rearers.

  4. Performance and welfare of steers housed on concrete slatted floors at fixed and dynamic (allometric based) space allowances.

    Science.gov (United States)

    Keane, Michael P; McGee, Mark; O'Riordan, Edward G; Kelly, Alan K; Earley, Bernadette

    2018-04-03

    The objectives of the study were to determine whether allometric equations are suitable for estimating the space requirements of finishing beef cattle housed on concrete slatted floors (CSF) and to examine the effect of fixed and dynamic space allowances on the performance and welfare of these cattle. Continental crossbred steers [n = 120: mean initial live weight, 590 (SD 29.8) kg] were blocked by breed, weight, and age and assigned to 1 of 5 space allowance treatments (3 fixed and 2 dynamic) on CSF: 1) 2.0 m2 per animal, 2) 2.5 m2 per animal, 3) 3.0 m2 per animal, 4) Equation 1 (E1); y = 0.033w0.667, where y = m2 per animal and w = body weight, and 5) Equation 2 (E2); y = 0.048w0.667. The length of the feed face was 3.0 m for all treatments. Steers were offered grass silage and concentrates ad libitum. DMI was recorded weekly on a pen basis. Steers were weighed and dirt scored every 14 d. Blood samples were collected every 28 d, and analyzed for complete cell counts. Behavior was recorded using closed-circuit infrared cameras. Steers' hooves were inspected for lesions at the beginning of the study and post-slaughter. Slaughter weight and ADG were lowest, and feed conversion ratio (FCR) was poorest, for steers accommodated at 2.0 m2, and slaughter weight and ADG were greatest, and FCR was the best, for steers accommodated at E2 (P 0.05) to those accommodated at 2.0 m2 and both 3.0 m2 and E1, whereas steers accommodated at 3.0 m2 and E1 were intermediate (P > 0.05) to 2.5 m2 and E2. Carcass weight of steers housed at 2.0 m2 was lower (P < 0.05) than all other treatments. Steers housed at 2.5 m2 had lower carcass weights (P < 0.05) than those with accommodated at E1 and E2, whereas the carcass weight of steers accommodated at 3.0 m2 was intermediate. Carcass fat scores and hide weights were lower (P < 0.05) in steers accommodated at 2.0 m2 than those housed at E2 with other treatments being intermediate. The number of steers lying at any one time and the number of

  5. Biological soil crusts across disturbance–recovery scenarios: effect of grazing regime on community dynamics.

    Science.gov (United States)

    Concostrina-Zubiri, L; Huber-Sannwald, E; Martínez, I; Flores Flores, J L; Reyes-Agüero, J A; Escude, A; Belnap, J

    Grazing represents one of the most common disturbances in drylands worldwide, affecting both ecosystem structure and functioning. Despite the efforts to understand the nature and magnitude of grazing effects on ecosystem components and processes, contrasting results continue to arise. This is particularly remarkable for the biological soil crust (BSC) communities (i.e., cyanobacteria, lichens, and bryophytes), which play an important role in soil dynamics. Here we evaluated simultaneously the effect of grazing impact on BSC communities (resistance) and recovery after livestock exclusion (resilience) in a semiarid grassland of Central Mexico. In particular, we examined BSC species distribution, species richness, taxonomical group cover (i.e., cyanobacteria, lichen, bryophyte), and composition along a disturbance gradient with different grazing regimes (low, medium, high impact) and along a recovery gradient with differently aged livestock exclosures (short-, medium-, long-term exclusion). Differences in grazing impact and time of recovery from grazing both resulted in slight changes in species richness; however, there were pronounced shifts in species composition and group cover. We found we could distinguish four highly diverse and dynamic BSC species groups: (1) species with high resistance and resilience to grazing, (2) species with high resistance but low resilience, (3) species with low resistance but high resilience, and (4) species with low resistance and resilience. While disturbance resulted in a novel diversity configuration, which may profoundly affect ecosystem functioning, we observed that 10 years of disturbance removal did not lead to the ecosystem structure found after 27 years of recovery. These findings are an important contribution to our understanding of BCS dynamics from a species and community perspective placed in a land use change context.

  6. Biological soil crusts across disturbance-recovery scenarios: effect of grazing regime on community dynamics

    Science.gov (United States)

    Concostrina-Zubiri, L.; Huber-Sannwald, E.; Martínez, I.; Flores Flores, J. L.; Reyes-Agüero, J. A.; Escudero, A.; Belnap, Jayne

    2014-01-01

    Grazing represents one of the most common disturbances in drylands worldwide, affecting both ecosystem structure and functioning. Despite the efforts to understand the nature and magnitude of grazing effects on ecosystem components and processes, contrasting results continue to arise. This is particularly remarkable for the biological soil crust (BSC) communities (i.e., cyanobacteria, lichens, and bryophytes), which play an important role in soil dynamics. Here we evaluated simultaneously the effect of grazing impact on BSC communities (resistance) and recovery after livestock exclusion (resilience) in a semiarid grassland of Central Mexico. In particular, we examined BSC species distribution, species richness, taxonomical group cover (i.e., cyanobacteria, lichen, bryophyte), and composition along a disturbance gradient with different grazing regimes (low, medium, high impact) and along a recovery gradient with differently aged livestock exclosures (short-, medium-, long-term exclusion). Differences in grazing impact and time of recovery from grazing both resulted in slight changes in species richness; however, there were pronounced shifts in species composition and group cover. We found we could distinguish four highly diverse and dynamic BSC species groups: (1) species with high resistance and resilience to grazing, (2) species with high resistance but low resilience, (3) species with low resistance but high resilience, and (4) species with low resistance and resilience. While disturbance resulted in a novel diversity configuration, which may profoundly affect ecosystem functioning, we observed that 10 years of disturbance removal did not lead to the ecosystem structure found after 27 years of recovery. These findings are an important contribution to our understanding of BCS dynamics from a species and community perspective placed in a land use change context.

  7. Displacement and force coupling control design for automotive active front steering system

    Science.gov (United States)

    Zhao, Wanzhong; Zhang, Han; Li, Yijun

    2018-06-01

    A displacement and force coupling control design for active front steering (AFS) system of vehicle is proposed in this paper. In order to investigate the displacement and force characteristics of the AFS system of the vehicle, the models of AFS system, vehicle, tire as well as the driver model are introduced. Then, considering the nonlinear characteristics of the tire force and external disturbance, a robust yaw rate control method is designed by applying a steering motor to generate an active steering angle to adjust the yaw stability of the vehicle. Based on mixed H2/H∞ control, the system robustness and yaw rate tracking performance are enforced by H∞ norm constraint and the control effort is captured through H2 norm. In addition, based on the AFS system, a planetary gear set and an assist motor are both added to realize the road feeling control in this paper to dismiss the influence of extra steering angle through a compensating method. Evaluation of the overall system is accomplished by simulations and experiments under various driving condition. The simulation and experiment results show the proposed control system has excellent tracking performance and road feeling performance, which can improve the cornering stability and maneuverability of vehicle.

  8. Investigating Einstein-Podolsky-Rosen steering of continuous-variable bipartite states by non-Gaussian pseudospin measurements

    Science.gov (United States)

    Xiang, Yu; Xu, Buqing; Mišta, Ladislav; Tufarelli, Tommaso; He, Qiongyi; Adesso, Gerardo

    2017-10-01

    Einstein-Podolsky-Rosen (EPR) steering is an asymmetric form of correlations which is intermediate between quantum entanglement and Bell nonlocality, and can be exploited as a resource for quantum communication with one untrusted party. In particular, steering of continuous-variable Gaussian states has been extensively studied theoretically and experimentally, as a fundamental manifestation of the EPR paradox. While most of these studies focused on quadrature measurements for steering detection, two recent works revealed that there exist Gaussian states which are only steerable by suitable non-Gaussian measurements. In this paper we perform a systematic investigation of EPR steering of bipartite Gaussian states by pseudospin measurements, complementing and extending previous findings. We first derive the density-matrix elements of two-mode squeezed thermal Gaussian states in the Fock basis, which may be of independent interest. We then use such a representation to investigate steering of these states as detected by a simple nonlinear criterion, based on second moments of the correlation matrix constructed from pseudospin operators. This analysis reveals previously unexplored regimes where non-Gaussian measurements are shown to be more effective than Gaussian ones to witness steering of Gaussian states in the presence of local noise. We further consider an alternative set of pseudospin observables, whose expectation value can be expressed more compactly in terms of Wigner functions for all two-mode Gaussian states. However, according to the adopted criterion, these observables are found to be always less sensitive than conventional Gaussian observables for steering detection. Finally, we investigate continuous-variable Werner states, which are non-Gaussian mixtures of Gaussian states, and find that pseudospin measurements are always more effective than Gaussian ones to reveal their steerability. Our results provide useful insights on the role of non

  9. DMSP and DMS dynamics and microzooplankton grazing in the Labrador Sea: application of the dilution technique

    Science.gov (United States)

    Wolfe, Gordon V.; Levasseur, Maurice; Cantin, Guy; Michaud, Sonia

    2000-12-01

    We adapted the dilution technique to study microzooplankton grazing of algal dimethylsulfoniopropionate (DMSP) vs. Chl a, and to estimate the impact of microzooplankton grazing on dimethyl sulfide (DMS) production in the Labrador Sea. Phytoplankton numbers were dominated by autotrophic nanoflagellates in the Labrador basin, but diatoms and colonial Phaeocystis pouchetii contributed significantly to phytomass at several high chlorophyll stations and on the Newfoundland and Greenland shelfs. Throughout the region, growth of algal Chl a and DMSP was generally high (0.2-1 d -1), but grazing rates were lower and more variable, characteristic of the early spring bloom period. Production and consumption of Chl a vs. DMSP followed no clear pattern, and sometimes diverged greatly, likely because of their differing distributions among algal prey taxa and size class. In several experiments where Phaeocystis was abundant, we observed DMS production proportional to grazing rate, and we found clear evidence of DMS production by this haptophyte following physical stress such as sparging or filtration. It is possible that grazing-activated DMSP cleavage by Phaeocystis contributes to grazer deterrence: protozoa and copepods apparently avoided healthy colonies (as judged by relative growth and grazing rates of Chl a and DMSP), and grazing of Phaeocystis was significant only at one station where cells were in poor condition. Although we hoped to examine selective grazing on or against DMSP-containing algal prey, the dilution technique cannot differentiate selective ingestion and varying digestion rates of Chl a and DMSP. We also found that the dilution method alone was poorly suited for assessing the impact of grazing on dissolved sulfur pools, because of rapid microbial consumption and the artifactual release of DMSP and DMS during filtration. Measuring and understanding the many processes affecting organosulfur cycling by the microbial food web in natural populations remain a

  10. X-ray diffraction study of surface-layer structure in parallel grazing rays

    International Nuclear Information System (INIS)

    Shtypulyak, N.I.; Yakimov, I.I.; Litvintsev, V.V.

    1989-01-01

    An x-ray diffraction method is described for study of thin polycrystalline and amorphous films and surface layers in an extremely asymmetrical diffraction system in parallel grazing rays using a DRON-3.0 diffractometer. The minimum grazing angles correspond to diffraction under conditions of total external reflection and a layer depth of ∼ 2.5-8 nm

  11. Effects of Seasonal and Perennial Grazing on Soil Fauna Community and Microbial Biomass Carbon in the Subalpine Meadows of Yunnan, Southwest China

    Institute of Scientific and Technical Information of China (English)

    LIU Shengjie; YANG Xiaodong; Anthony R.IVES; FENG Zhili; SHA Liqing

    2017-01-01

    Grazing and over-grazing may drive changes in the diversity and functioning of below-ground meadow ecosystems.A field soil survey was conducted to compare microbial biomass carbon (Cmin) and soil fauna communities in the two main grassland management systems in subalpine regions of Yunnan Province,China:perennial grazing currently practiced due to increasing herd sizes and traditional seasonal grazing.A three-year exclosure experiment was then conducted to further compare the effects of different grazing practices,including treatments of no mowing,perennial grazing (NM + G),mowing followed by seasonal grazing (M + G),mowing and no grazing (M + NG),and no mowing or grazing (NM + NG).The comparative survey result revealed that Cmin and total density of soil fauna were significantly lower at a perennially grazed site than at a seasonally grazed site.The experiment results showed that in comparison to non-grazing treatments (M + NG and NM + NG),grazing (NM + G and M + G) reduced total fauna density (by 150 individuals m-2) and the number of taxonomic groups present (by 0.32 taxa m-2).Mowing decreased Cmin (by 0.31 mg g-1).Furthermore,the NM + G treatment (perennial grazing) had the lowest density of Collembola (16.24 individuals m-2),one of the two most common taxonomic groups,although other taxonomic groups responded differently to the treatments.Treatment effects on soil fauna were consistent with those on above-ground grasses,in which C:N ratios were greatly reduced by grazing,with this effect being the greatest for the NM + G treatment.In contrast,different grazing treatments had little effect on C:N ratio of soil.Furthermore,the traditional grazing method (mowing followed by seasonal grazing) may have less severe effects on some taxonomic groups than perennial grazing.Therefore,an appropriate management should aim to protect soil fauna and microbes in this area from over-grazing and against further degradation.

  12. Steering straight

    Energy Technology Data Exchange (ETDEWEB)

    Louie, Jacqueline

    2011-12-15

    Baker Hughes Inc. has developed a deep azimuthal resistivity measurement tool for subsurface navigation when drilling oil and gas wells. This tool, named AziTrak, has measurement-while-drilling and logging-while-drilling capabilities and data are sent in real time to the surface via mud pulse or wired pipe telemetry. This technology helps the operator detect and visualize bed boundaries in real time, thanks to 3D imagery and a 360 degree view of the subsurface. The AziTrak system makes it possible to steer proactively and to stay within the pay zone at all times to maximize production; the tool had excellent results in field applications. Although this tool is 5 times more expensive than conventional technologies, its use results in a more economic wellbore thanks to its great utility. If the operator puts a high degree of involvement into it, the AziTrak deep azimuthal resistivity measurement tool will allow him to stay in the pay zone at all times.

  13. The role of grazing in nutrient-rich areas of the open sea

    International Nuclear Information System (INIS)

    Frost, B.W.

    1991-01-01

    No single factor accounts fully for the persistently low phytoplankton stocks in the nutrient-rich areas of the open sea. However, grazing plays the necessary role of consuming phytoplankton produced in excess of losses due to physical processes and sinking. Without grazing, even if specific growth rate of the phytoplankton is less than optimal for the prevailing light and temperature conditions, as might be so under limitation by a trace nutrient such as Fe, the phytoplankton stock would still accumulate with attendant depletion of nutrients. Observations during spring and summer in the open subarctic Pacific argue against limitation of phytoplankton growth to the point where phytoplankton stock could not increase in the absence of grazing. An ecosystem process model of the phytoplankton-grazer interaction suggests that two processes - grazing control of phytoplankton stock and preferential utilization of NH 4 by the phytoplankton - are sufficient to explain the continuously low phytoplankton stock and high concentrations of macronutrients. However, the grazing control may be exerted on a phytoplankton assemblage structured by Fe limitation. In particular, the intrinsic growth rates of potentially fast-growing diatoms seem to be depressed in the open subarctic Pacific. These conditions probably apply to two other nutrient-rich areas of the open sea, the Pacific equatorial upwelling region and the subantarctic circumpolar ocean, although in the latter region light limitation of phytoplankton growth may be more severe and silica limitation may influence the specific composition of the phytoplankton assemblage

  14. Non-traditional Forages in a Managed Grazing System for Control of Gastrointestinal Parasites in Sheep: Preliminary Work

    Science.gov (United States)

    This project compared lambs grazing forage chicory (Cichorium intybus L.) with lambs grazing brown mid-rib forage sorghum (Sorghum bicolor (L.) Moench.) x sudangrass (Sorghum sudanense Piper) hybrid (BMR) to determine if anti-parasitic effects of chicory could be demonstrated. Lambs grazed these fo...

  15. Competition between two grass species with and without grazing over a productivity gradient

    NARCIS (Netherlands)

    Kuijper, D.P.J.; Dubbeld, J.; Bakker, J.P.

    2005-01-01

    Soil nutrient-level and herbivory are predicted to have opposing effects on the allocation pattern of the competitive dominant plant species. Lower stem and higher leaf allocation are favoured when plants are grazed, whereas a higher stem allocation is favoured at high nutrient levels. Grazing by

  16. The impact of sheep grazing on the carbon balance of a peatland

    Energy Technology Data Exchange (ETDEWEB)

    Worrall, Fred, E-mail: Fred.Worrall@durham.ac.uk; Clay, Gareth D.

    2012-11-01

    Estimates of the greenhouse gas (GHG) fluxes resulting from sheep grazing upon upland peat soils have never been fully quantified. Previous studies have been limited to individual flux pathways or to comparing the presence to the absence of sheep grazing. Therefore, this study combines a model of the physical impact of grazing with models of: biomass production; energy usage in sheep; and peat accumulation. These combined modelling approaches enabled this study to consider the indirect and direct impacts of sheep upon the carbon and greenhouse gas balance of a peatland at different grazing intensities as well as the changes between grazing intensities. The study considered four vegetation scenarios (Calluna sp., Molinia sp.; reseeded grasses, and Agrostis-Festuca grassland) and a mixed vegetation scenario based upon the vegetation typical of upland peat ecosystems in northern England. Each scenario was considered for altitudes between 350 and 900 m above sea level and for grazing intensities between 0.1 and 2 ewes/ha. The study can show that the total GHG flux at the vegetative carrying capacity tended to decline with increasing altitude for all vegetation scenarios considered except for Molinia sp. The average total GHG flux for all scenarios was 1505 kg CO{sub 2}eq/ha/yr/(ewe/ha), and on average 89% of the fluxes were directly from the sheep and not from the soil, and are therefore not unique to a peat soil environment. The study suggests that emission factors for upland sheep have been greatly underestimated. By comparing the total flux due to grazers to the flux to or from the soil that allows the study to define a GHG carry capacity, i.e. the grazing intensity at which the flux due to grazing is equal to the sink represented by the peat soils, this GHG carrying capacity varies between 0.2 and 1.7 ewes/ha with this capacity declining with increasing altitude for all model scenarios. -- Highlights: Black-Right-Pointing-Pointer Vegetative carrying capacity was

  17. [A comparative study on soil respiration between grazing and fenced typical Leymus chinensis steppe, Inner Mongolia].

    Science.gov (United States)

    Jia, Bingrui; Zhou, Guangsheng; Wang, Fengyu; Wang, Yuhui

    2004-09-01

    With enclosed chamber Method, this paper studied the soil respiration in grazing and fenced typical Leymus chinensis steppes, Inner Mongolia, and its relationships with environmental factors. The results showed that the daily pattern of soil respiration could be expressed as a one-humped curve, and the highest values appeared at 13:00-15:00 in the fenced and grazing plots. The diurnal dynamics of soil respiration mainly depended on the surface temperature at the fenced plots and the soil temperature at 5 cm depth at the grazing plots. In June and July, the average soil respiration rate was 2.7 times greater at the fenced plots than that at the grazing plots, while the difference was not distinct in August and September, which was similar with the change of the belowground biomass. The reason was probably that the plant was influenced differently in different phenological phases by grazing and the change of environmental factors. It showed that human activity may not result in the increase of soil respiration rate. The seasonal dynamics of soil respiration was closely correlated with soil water content at the 0-10 cm depth at the fenced and grazing sites, and the maximum R2 was 0.853 and 0.741, respectively. The difference was that the correlation of soil respiration seasonal dynamics with soil water content was larger at the fenced plots than at the grazing plots. The correlations of soil respiration diurnal and seasonal dynamics with temperature and soil water content at lower profiles were larger than those at deeper profiles at the fenced and grazing sites.

  18. Evaluation of metal matrix composite to replace spheroidal graphite iron for a critical component, steering knuckle

    International Nuclear Information System (INIS)

    Vijayarangan, S.; Rajamanickam, N.; Sivananth, V.

    2013-01-01

    Highlights: ► A FE model is developed to study the suitability of MMC for steering knuckle. ► Structural analysis of steering knuckle is carried out for 12 load cases. ► The cross section of the critical region is optimized using genetic algorithm. ► The life of the MMC (Al-10 wt.% TiC) knuckle is compared before and after optimization. ► MMC material could replace SG iron for automotive steering knuckle. -- Abstract: Steering knuckle is considered as one of the critical component in automotive suspension system. It is subjected to time varying loads during its service life, leading to fatigue failure. Therefore, its design is an important aspect in the product development cycle. Currently, spheroidal graphite (SG) iron is widely used to manufacture steering knuckle in the commercial automobile sector. It has been observed from the knuckle manufacturers that advanced materials and weight reduction are the real need for the current automobile industry. Due to their high strength to weight ratio, Metal Matrix Composites (MMCs) have the potential to meet the demanded design requirements of the automotive industry, compared to conventional materials. In this work, an aluminum alloy reinforced with titanium carbide particulate is suggested as an alternate material in place of existing SG iron. Structural analysis of steering knuckle made of alternate material Al-10 wt.% TiC was performed using commercial code ANSYS. The results of steering knuckle made of MMC (Al-10 wt.% TiC) were compared with that of aluminum alloy and SG iron steering knuckles for its performance based on real time load cases. It is found from this analysis, the knuckle strut region has maximum stress and deflection during its life time. The critical strut region cross section area of knuckle was analyzed and geometrically optimized for minimum bending stress and deflection using genetic algorithm available in MatLab. Since, the knuckle experiences time varying loads, fatigue analysis also

  19. Wet Gas Airfoil Analyses

    OpenAIRE

    Larsen, Tarjei Thorrud

    2011-01-01

    Subsea wet gas compression renders new possibilities for cost savings and enhanced gas recovery on existing gas wells. Technology like this opens to make traditional offshore processing plants redundant. With new technology, follows new challenges. Multiphase flows is regarded as a complex field of study, and increased knowledge on the fundamental mechanisms regarding wet gas flow is of paramount importance to the efficiency and stability of the wet gas compressor. The scope of this work was ...

  20. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...