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This paper reviews the effects of extended lactation (EXT) as a strategy in dairy cattle on milk production and persistency, reproduction, milk quality, lifetime performance of the cow and finally the economic effects on herd and farm levels as well as the impact on emission of greenhouse gas at product level. Primiparous cows are able to produce equal or more milk per feeding day during EXT compared with a standard 305-d lactation, whereas results for multiparous cows are inconsistent. Cows managed for EXT can achieve a higher lifetime production while delivering milk with unchanged or improved quality properties. Delaying insemination enhances mounting behaviour and allows insemination after the cow’s energy balance has become positive. However, in most cases EXT has no effect or a non-significant positive effect on reproduction. The EXT strategy sets off a cascade of effects at herd and farm level. Thus, the EXT strategy leads to fewer calvings and thereby expected fewer diseases, fewer replacement heifers and fewer dry days per cow per year. The optimal lifetime scenario for milk production was modelled to be an EXT of 16 months for first parity cows followed by an EXT of 10 months for later lactations. Modelling studies of herd dynamics indicate a positive effect of EXT on lifetime efficiency (milk per dry matter intake), mainly originating from benefits of EXT on daily milk yield in primiparous cows and the reduced number of replacement heifers. Consequently, EXT also leads to reduced total meat production at herd level. For the farmer, EXT can give the same economic return as a traditional lactation period. At farm level, EXT can contribute to a reduction in the environmental impact of dairy production, mainly as a consequence of the reduced production of beef. A wider dissemination of the EXT concept will be supported by methods to predict which cows may be most suitable for EXT, and clarification of how milking frequency and feeding strategy through the lactation can be organised to support milk yield and an appropriate body condition at the next calving.
Weaning is a critical transition phase in swine production in which piglets must cope with different stressors that may affect their health. During this period, the prophylactic use of antibiotics is still frequent to limit piglet morbidity, which raises both economic and public health concerns such as the appearance of antimicrobial-resistant microbes. With the interest of developing tools for assisting health and management decisions around weaning, it is key to provide robustness indexes that inform on the animals’ capacity to endure the challenges associated with weaning. This work aimed at developing a modelling approach for facilitating the quantification of piglet resilience to weaning. A total of 325 Large White pigs weaned at 28 days of age were monitored and further housed and fed conventionally during the post-weaning period without antibiotic administration. Body weight and diarrhoea scores were recorded before and after weaning, and blood was sampled at weaning and 1 week later for collecting haematological data. A dynamic model was constructed based on the Gompertz–Makeham law to describe live weight trajectories during the first 75 days after weaning, following the rationale that the animal response is partitioned in two time windows (a perturbation and a recovery window). Model calibration was performed for each animal. Our results show that the transition time between the two time windows, as well as the weight trajectories are characteristic for each individual. The model captured the weight dynamics of animals at different degrees of perturbation, with an average coefficient of determination of 0.99, and a concordance correlation coefficient of 0.99. The utility of the model is that it provides biologically meaningful parameters that inform on the amplitude and length of perturbation, and the rate of animal recovery. Our rationale is that the dynamics of weight inform on the capability of the animal to cope with the weaning disturbance. Indeed, there were significant correlations between model parameters and individual diarrhoea scores and haematological traits. Overall, the parameters of our model can be useful for constructing weaning robustness indexes by using exclusively the growth curves. We foresee that this modelling approach will provide a step forward in the quantitative characterisation of robustness.
In early lactation, most of the dairy cows are in negative energy balance; the extent and duration depend in part on the feeding strategy. Previous studies showed an increased lactation milk yield by use of a live weight (LW) adjusted feeding strategy with a high energy diet before and a reduced energy diet after LW nadir compared with a standard diet throughout lactation. The objective of the present study was to examine how such an individualized feeding strategy affects plasma indicators of energy status. It was hypothesized that an energy-enriched diet until LW nadir will reduce the severity of the negative energy balance, and that the reduction in diet energy concentration from LW nadir will extend the negative energy balance period further. Sixty-two Holstein cows (30% first parity) were managed for 16 months extended lactation and randomly allocated to one of two feeding strategies at calving. Two partially mixed rations were used, one with a high energy density (HD) and a 50 : 50 forage : concentrate ratio, and one with a lower energy density (LD, control diet) and a 60 : 40 forage : concentrate ratio. Half of the cows were offered the HD diet until they reached at least 42 days in milk and a LW gain⩾0 kg/day based on a 5-days LW average, and were then shifted to the LD diet (strategy HD-LD). The other half of the cows were offered the LD diet throughout lactation (control strategy LD-LD). Weekly blood samples were drawn for analysis of plasma metabolites and hormones. Before the shift in diet, the HD-LD cows had higher glucose and lower beta-hydroxybutyrate and non-esterified fatty acids (NEFA) concentrations than the LD-LD cows. After the shift until 36 weeks after calving, plasma NEFA was higher in HD-LD than LD-LD cows. Insulin and insulin-like growth factor-1 were not affected by the feeding strategy. To conclude, in early lactation, the energy-enriched diet reduced the negative energy balance. Plasma NEFA was higher in HD-LD than LD-LD cows from diet shift until 36 weeks after calving, indicating a carry-over effect of the early lactation HD diet to late lactation metabolism.
The Didwana region has preserved lower palaeolithic artefacts in primary and semi-primary contexts. On the basis of geological stratigraphy of aeolian and playa sediments, artefacts occurring in a stratified context have been dated to the Middle Pleistocene. In order to work out technological evolutionary trends of the acheulian culture in this region, 301 handaxes from 10 localities have been studied following Roe's methodology, with some additional attributes. Some differences in size, shape and refinement are apparent between the collections. Statistics, diagrams, factor and cluster analyses suggest a technological evolution within the assemblages and therefore indicate the chronology of the sites. Compared with those of other known Indian sites, these handaxes may correspond to cultural stages ranging between early acheulian and very late acheulian or even early middle palaeolithic.
The role of Campylobacter jejuni as the triggering agent of Guillain–Barré syndrome (GBS) has not been reassessed since the end of the 1990s in France. We report that the number of C. jejuni-related GBS cases increased continuously between 1996 and 2007 in the Paris region (mean annual increment: 7%, P = 0·007).
We report in this communication on the photoelectrochemical (PEC) performances of copper tungstate (CuWO4) material class. This study was performed on 2-micron thick samples fabricated using a low-cost co-sputtering deposition process, followed by an 8-hour long annealing at 500°C in argon. Microstructural analysis pointed out that the post-deposition treatment was critical to achieve photocatalytic activity. Subsequent characterizations revealed that polycrystalline CuWO4 photoanodes owned promising characteristics for solar-assisted water splitting, i.e (i) an optical band-gap of 2.2 eV, (ii) a flat-band potential of -0.35 V vs. SCE and (iii) conduction and valence band-edges that straddle water splitting redox potentials. CuWO4 photoanodes generated 400 μA.cm-2 at 1.6V vs. SCE under simulated AM1.5G illumination in 0.33M H3PO4 with virtually no dark current up to this potential. Impedance analysis pointed out that large charge transfer resistances (2,500 Ω.cm2) could be the main weakness of this material class. Current research activity is focused on solving this issue to achieve higher PEC performances.
Plasma enhanced CVD produces carbon layers with various properties which are highly correlated to the different process parameters such as monomer structure, plasma type or plasma power. For example, the modification of monomer (CH4 to C4H10) or the plasma source and the increase of plasma power lead to an optical band-gap which runs from 0.9 to 4.3eV, a conductivity from 5·103 to 5·105S.m−1 and a refractive index from 1.47 to 2.76. Then, it is able to control the optical and electrical film properties from the external process parameters. This paper will thus be focused on the description of relation between deposition parameters, structural characteristics of material and film properties. These materials can then be used for optoelectronics applications.
In this letter, we report on Work Function (WF) measurements performed at deca-nanometer scale on various metals using Kelvin probe Force Microscope (KFM). We first demonstrated the relationship between the WF value and the grain crystallographic orientation by combining KFM and Electron Back Scattered Diffraction (EBSD) performed over the same Cu area. Once this relationship was established, KFM was used to provide, in addition to WF value, crystallographic properties of TiN PVD films grown on various substrates. Finally we characterized the effect of N2/H2 plasma treatment on the WF of TiN grown by CVD. In the latter case, the modification of the bulk chemical potential by post-treatment was proposed.
Abundant and diverse trace fossils occur in deposits, recording an Early Devonian transgression in Bolivia. the very well-exposed Presto-El Peral section is located in the Interandean Belt 50 km northeast of Sucre. Trace fossils can be assigned to five associations from nearshore to offshore environments (namely Skolithos, Diplocraterion, Altichnus, Palaeophycus, and Zoophycos associations). They clearly illustrate the different colonization phases of the benthos with increasing marine influence. A deeper-water Helminthopsis association occurs in other complementary sections on the Eastern Cordillera. Variation of bioturbation intensity, ichnodiversity, and preservation potential is evaluated. the morphology of traces, mainly deep burrows, shows a significant gradient related to the behavior of tracemakers and the environmental changes. Main trends are consistent with the Seilacherian bathymetric model which is detailed here and/or emended with a well-exposed field example. A precise correlation is proposed with fossil benthic associations dominated by brachiopods. the whole gives an accurate model for benthos colonization and benthic marine zonation.
A detailed investigation of many aspects of the physics
of laser–plasma interaction at very high laser
intensities is required in order to assess the feasibility
and the promise of the fast ignitor scheme for inertial
confinement fusion. Relevant results, obtained in a series
of experiments carried out at the Rutherford Appleton Laboratory,
Chilton (UK) and at the Centre d'Etudes Atomique,
Limeil Valenton (France), are presented and discussed here.
In particular, the formation of plasma channels was observed
following the propagation of relativistically intense,
ps laser pulses through underdense plasmas. The channels
persist long after the interaction, and their expansion
has been measured. Efficient guiding of ultraintense laser
pulses, both through preformed density channels and through
solid guides, has been demonstrated. Finally, indication
of collimated fast electron propagation through solid targets
has been obtained from the observation of filamentary ionization
tracks in laser irradiated solid targets.
The highest duty of an American diplomatic or consular officer is to protect citizens of the United States in lawful pursuit of their affairs in foreign countries. The document issued in authentication of the right to such protection is the passport.
Broadly speaking, the Department issues two kinds of passports — those for citizens and those for persons who are not citizens. Citizens’ passports are ordinary and special; aliens’ passports are for travel in the United States and for qualified protection abroad of those who have taken the first steps to become American citizens.
The citizen’s passport is the only document issued by the Department of State to authenticate the citizenship of an American going abroad. The Act of August 18, 1856, makes the issuance to one who is not a citizen a penal offense if it is committed by a consular officer. Before this law was passed the Department did not issue the document to aliens; but it was permitted to this government’s agents abroad sometimes to issue it to others than American citizens. The Personal Instructions to the Diplomatic Agents of the United States of 1853 said:
They sometimes receive applications for such passports from citizens of other countries; but these are not regularly valid, and should be granted only under special circumstances, as may sometimes occur in the case of foreigners coming to the United States.
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