The effect of paddock size on the response of seasonal anoestrous ewes to the ram effect

Many aspects of the conditions required to maximize the ewe's response to ram introduction in the late anoestrous season remain unclear. The aim of this research was to determine whether grazing space allowances could influence the efficacy of the ram effect. In August 1995, at Reading (latitude 51degrees27'N), following a 3-month isolation period from rams, two groups of nulliparous Mule ewes, aged 15 months, were introduced to four rains in a low (12 ewes/ha; treatment L, n = 124) or in a high stocking rate (84 ewes/ha; treatment H, n = 126). From the beginning of August until the end of August oestrous behaviour was recorded by daily checks of mating marks on ewes. Rams were removed and in October all ewes were scanned (day 50) for pregnancy. No significant differences were found in the parameters investigated. Eighty-two percent of the L and 75.4% of the H ewes exhibited oestrus, with a pronounced peak on day 23 following ram introduction and a compact concentration in the 21-25-day period. The oestrous synchronisation rate in this 5-day period was 69.4 and 68.3%, respectively for L and H. The mean interval from ram introduction to oestrus was 23.17+/-2.4 days in L and 23.0+/-2.2 days in the H group. Conception rates were 84.3 and 87.4% for L and H groups, respectively. These results suggest that the response of anoestrous ewes to the introduction of rams was not affected by grazing space allowances and that yearling Mule ewes respond well to the ram effect in the late anoestrus season. (C) 2003 Elsevier Science B.V. All rights reserved.

Protocolos de indução e sincronização do estro em ovelhas

O objetivo do presente trabalho foi testar a indução e sincronização do estro em ovelhas utilizando-se diferentes períodos de permanência do progestágeno, dose única de PGF2α ou efeito macho. Para tanto dois experimentos foram realizados: no experimento 1, as ovelhas (n=48) receberam esponjas vaginais impregnadas com MAP (medroxiprogesterona) e foram divididas em 2 grupos: G-9 e G-14, ou seja, MAP por nove ou 14 dias com aplicação de PGF2α na retirada do progestágeno e detecção de estro com reprodutores. Não houve diferenças (p<0,05) na manifestação no estro (69,6 % e 80%), na porcentagem de prenhez (34,8% e 44%) ou de concepção (50% e 55%) nos grupos G-9 e G-14, respectivamente. No experimento 2, as ovelhas (n=151) foram aleatoriamente divididas em 3 grupos: G-6, cada ovelha recebeu MAP por seis dias e aplicação de PGF2α na retirada do progestágeno; G-PGF, cada ovelha recebeu dose única de PGF2α e G-EM para avaliar o efeito macho foram introduzidos machos entre ovelhas previamente separadas dos mesmos. A porcentagem de manifestação de estro foi maior (p<0,05) nos grupos G-6 (58%) e G-PGF (39%) quando comparados ao G-EM (11%). Concluímos ser possível diminuir o tempo de permanência do progestágeno, porém o uso de luteolítico, em período de transição da estacionalidade reprodutiva, sem o progestágeno, resulta em baixa manifestação de estro.

The effect of ram replacement and sex ratio on the sexual response of anoestrous ewes

It is accepted that an important source of variation in the response of anoestrous ewes, to the introduction of rams, is the intensity of male stimulation. The aim of this study was to investigate strategies capable of increasing the impact and transmission of the ram stimuli. In Experiment 1, two groups of seven ewes (Bluefaced Leicester male x Swaledale female) were individually penned with one ram and for the next 6 h the rams either remained in the pen or were replaced hourly. Blood samples revealed no difference in the pattern of plasma LH secretion. In Experiment 2, three groups of 16 ewes were either introduced to one ram, individually (H) or in groups of 8 (L), or remained isolated. Ram introduction increased the plasma LH pulsatility (P < 0.001). H ewes displayed more (nine versus six) male-induced LH pulses (pulses occurring within the first 45 min) and more pulses per 8 h intervals than the L group of ewes (1.9 +/- 0.3 versus 1.3 +/- 0.3), but these differences were not significant. It was concluded that (i) frequent replacement of rams within a few hours following ram introduction to ewes does not further improve the response of ewes, especially if the ram:ewe ratio is high; (ii) the characterization of the plasma LH secretion parameters during a period of 6-8 h does not seem to be an effective method to detect small differences in the intensity of stimulation received by the ewes when exposed to rams; (iii) North Country Mule ewes (Bluefaced Leicester male x Swaledale female) in the UK respond to the presence of rams in spring (late oestrous/early anoestrous season) with an elevation in plasma LH secretion. (c) 2005 Elsevier B.V. All rights reserved.

Junction Field Effect on the Retention Time for One-Transistor Floating-Body RAM

One-transistor floating-body random access memory retention time distribution is investigated on silicon-on-insulator UTBOX devices. It is shown that the average retention time can be improved by two to three orders of magnitude by reducing the body-junction electric field. However, the retention time distribution, which is mainly caused by the generation-recombination center density variation, remains similar.

Effect of ß-Mercaptoetanol and cysteine on post-thawing quality and oxidative activity of ram sperm and on the viability of vitrified sheep embryos.

2016

Effect of added nitrogen on plant litter decomposition depends on initial soil carbon and nitrogen stoichiometry

Increasing organic carbon inputs to agricultural soils through the use of pastures or crop residues has been suggested as a means of restoring soil organic carbon lost via anthropogenic activities, such as land use change. However, the decomposition and retention of different plant residues in soil, and how these processes are affected by soil properties and nitrogen fertiliser application, is not fully understood. We evaluated the rate and extent of decomposition of 13C-pulse labelled plant material in response to nitrogen addition in four pasture soils of varying physico-chemical characteristics. Microbial respiration of buffel grass (Cenchrus ciliaris L.), wheat (Triticum aestivum L.) and lucerne (Medicago sativa L.) residues was monitored over 365-days. A double exponential model fitted to the data suggested that microbial respiration occurred as an early rapid and a late slow stage. A weighted three-compartment mixing model estimated the decomposition of both soluble and insoluble plant 13C (mg C kg−1 soil). Total plant material decomposition followed the alkyl C: O-alkyl C ratio of plant material, as determined by solid-state 13C nuclear magnetic resonance spectroscopy. Urea-N addition increased the decomposition of insoluble plant 13C in some soils (≤0.1% total nitrogen) but not others (0.3% total nitrogen). Principal components regression analysis indicated that 26% of the variability of plant material decomposition was explained by soil physico-chemical characteristics (P = 0.001), which was primarily described by the C:N ratio. We conclude that plant species with increasing alkyl C: O-alkyl C ratio are better retained as soil organic matter, and that the C:N stoichiometry of soils determines whether N addition leads to increases in soil organic carbon stocks.

Unconjugated Bilirubin exerts Pro-Apoptotic Effect on Platelets via p38-MAPK activation

Thrombocytopenia is one of the most frequently observed secondary complications in many pathological conditions including liver diseases, where hyperbilirubinemia is very common. The present study sought to find the cause of thrombocytopenia in unconjugated hyperbilirubinemic conditions. Unconjugated bilirubin (UCB), an end-product of heme catabolism, is known to have pro-oxidative and cytotoxic effects at high serum concentration. We investigated the molecular mechanism underlying the pro-apoptotic effect of UCB on human platelets in vitro, and followed it up with studies in phenylhydrazine-induced hyperbilirubinemic rat model and hyperbilirubinemic human subjects. UCB is indeed found to significantly induce platelet apoptotic events including elevated endogenous reactive oxygen species generation, mitochondrial membrane depolarization, increased intracellular calcium levels, cardiolipin peroxidation and phosphatidylserine externalization (p < 0.001) as evident by FACS analysis. The immunoblots show the elevated levels of cytosolic cytochrome c and caspase activation in UCB-treated platelets. Further, UCB is found to induce mitochondrial ROS generation leading to p38 activation, followed by downstream activation of p53, ultimately resulting in altered expression of Bcl-2 and Bax proteins as evident from immunoblotting. All these parameters conclude that elevated unconjugated bilirubin causes thrombocytopenia by stimulating platelet apoptosis via mitochondrial ROS-induced p38 and p53 activation.

Effect of L-Prolyl-L-Leucyl-Glycinamide (PLG) on Neuroleptic-Induced Catalepsy and Dopamine/Neuroleptic Receptor Bindings

Effect of L-prolyl-cinagta tlheep spyo atenndt idaol paanmti-iPnaer/nkeinusroonleiapnti cp rreocpeeprttoiers b oifn dLi-npgrso.lyPl E-LP-TleIuDcEylS- g2l(y1c)Li n1-a0lem5u-ic1dy1el1-g,(Ply1Lc9iG8n1)a. mw-Taidhsee i nm(vPeeLcstGhiag) anotinesmd n ie onuf rb oaelchetapiovtinico -suuirnbadslu eacrnevddetnarflefetueeacrrtmto a coephfnp ePtrmLe(2icGc0iaa, lob4 mnl0y io atndnhedevl sii8tn r0oto fem dndgosoi ppktyaag mm o-1fii nn tSeehCr/eng cteiwcau tfiracuolenle edpcptattiiioiclcny r r feienoscrp et ohfpinetvos erer ad ebtali.iyncAsdit)cienusdgit ge bin nyai dfrhimacaatli nonsttpilrseytirar aiatdtuttoimeolnn u(a3aso tmfde PidgfL f hkeGargel -o(n'p2tI0ieaPr ali)ldn.y odB ll ay4-b 0icne omldlneugtdc rk eabgdsy t - c1,aa pcSthoaCrmleo)ponfrsaicypil .heP TidLn hteGoe pahnidn esp tior odpoepraimdoinl ew raesc aelpstoo ersx ainm tihnee dst.rPiaLtuGm s,elbeuctt ihvaedly n eon ehfafneccte don t h['eH a]ffsipniirtoyp oefr tidhoel sbpiencdifinicg .b Tinhdei nbge hoafv aigouonraislt an[3dH b] iaopcohmemori-- cal results obtained in the present study raise the possibility that PLG may facilitate nigro-striatal dopaminergic neurotransmission through interacting with a unique PLG receptor functionally coupled to the dopamine receptor cyclase complex. -adenylate

Lipid peroxidation and generation of hydrogen peroxide in frozen-thawed ram semen cryopreserved in extenders with antioxidants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Trehalose and a calcium chelator for ram semen cryopreservation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A new basic effect in retarding potential analyzers

The Retarding Potential Analyzer (RPA) is the standard instrument for in situ measurement of ion temperature and other ionospheric parameters. The fraction of incoming ions rejected by a RPA produces perturbations that reach well ahead of a thin Debye sheath, a feature common to all collisionless, hypersonic flows past ion-rejecting bodies. This phenomenon is here found to result in a correction to Whipple’s classical law for the current characteristic of an ideal RPA sheath thin; inverse ram ion Mach number M-1, and ram angle of RPA aperture u, small or moderately small.

An exploration of the effect of super large n-tuples on single layer RAMnets

N-tuple recognition systems (RAMnets) are normally modeled using a small number of input lines to each RAM, because the address space grows exponentially with the number of inputs. It is impossible to implement an arbitrarily-large address space as physical memory. But given modest amounts of training data, correspondingly modest numbers of bits will be set in that memory. Hash arrays can therefore be used instead of a direct implementation of the required address space. This paper describes some exploratory experiments using the hash array technique to investigate the performance of RAMnets with very large numbers of input lines. An argument is presented which concludes that performance should peak at a relatively small n-tuple size, but the experiments carried out so far contradict this. Further experiments are needed to confirm this unexpected result.

Do the lichens Xanthoparmelia conspersa (Ach.) Hale and Rhizocarpon Ram. Em. Th. Fr. subgenus Rhizocarpon utilise exogenous carbohydrates for radial growth?

To field test the hypothesis that lichen thalli can use environmental sources of carbon, solutions of ribitol, arabitol and mannitol were added to intact thalli of Xanthoparmelia conspersa (Ach.) Hale and a yellow species of Rhizocarpon (Rhizocarpon Ram. Em. Th. Fr. subgenus Rhizocarpon). In addition, ribitol and an arabitol/mannitol mixture were added to the marginal hypothalli of Rhizocarpon thalli after removal of the areolae. Carbohydrates were added at the beginning of 2- or 3-month growth periods for up to 15 months at concentrations approximately three times the levels estimated to be in the thalli. Addition of carbohydrates to intact thalli of both species had no effect on total radial growth but addition of mannitol significantly increased growth of X. conspersa thalli in the September/October growth period in one experiment. However, this effect was not repeated in a subsequent experiment in which different concentrations of mannitol were added to intact thalli. Addition of ribitol to hypothalli of Rhizocarpon resulted in significantly increased growth in the first few months of the experiment, growth then declining to levels below that of untreated thalli. The data suggest that although hypothalli of Rhizocarpon may have the ability to utilise exogenous carbohydrates for growth, there was little evidence that intact thalli of either species utilise environmental sources of carbon in the field.