Effects of Fasting on Ingestive Behaviour of Sheep Grazing Grass or White Clover Monocultures

Effects of fasting sheep for 24 h (F), compared with controls (NF), on their ingestive behaviour and particle size in extrusa was investigated using oesophageally fistulated animals, grazing monocultures of Lolium perenne (G) or Trifolium repens (C). Bite masses tended to be lower on G than C and tended to increase with fasting (40, 64, 61 and 70 mg DM bite-1) for treatments GNF, GF, CNF and CF, respectively. Prehension rate was lower (52 vs. 69 bites min-1) and masticating rate was higher (106 vs.86 mastications min- 1) for G and C treatments, respectively. Over 24 h following fasting, NF animals grazed less (458 vs. 578 min 24 h-1) and ruminated less (276 vs. 348 min 24 h-1) than F animals. Particles in extrusa \u3c 0.18 mm were 48 vs. 55 %, for G and F, and 49 vs.54% for F and NF treatments

How do Cattle and Sheep Alter Ingestive Behaviour in Response to Changes in Sward State?

Ingestive behaviour of yearling Friesian heifers continuously stocked on monocultures of Lolium perenne (G) or Trifolium repens (C) maintained at sward heights of 7-8 cm, was recorded. Bite masses, prehension biting and mastication rates were similar between treatments (211 vs. 230 mg DM prehension bite-1, 61 vs. 55 prehension bites and 11 vs. 13 mastications, min-1 for G and C, respectively). DM intake rates were 12.9 g min-1 for both treatments. Animals grazed longer (536 vs.436 min) and ruminated longer (526 vs. 267 min-1) on G compared with C. Daily intakes were 6.9 vs.5.6 kg DM for G and C. Growth rates for G and C were similar (0.97 vs 0.99 kg live weight d-1). Grass had a lower digestibility than clover (DOMD 60 vs. 77%). It is suggested that cattle have higher intake rates than do sheep because a lower proportion of their total jaw movements are used to masticate herbage

The Effect of Slurry and Dirty Water Application to Swards on Grazing Behaviour in Dairy Cows

In preference tests using pairs of turves in boxes (treated and control), dairy cows were more averse to surface spread than shallow injected slurry and more averse to slurry than dirty water. Effects of slurry persisted for up to 6 weeks, with fewer bites and less herbage removed from treated swards compared to control swards. Aversion to slurry may be decreased by injection. Effects of dirty water persisted for only 14 days

The time-dependent expression of keratins 5 and 13 during the reepithelialization of human skin wounds

The time-dependent reepithelialization of 55 human surgical skin wounds with a wound age between 8h and more than 2 months was investigated by the immunohistochemical localization of cytokeratins 5 and 13. A complete, rebuilt epidermal layer over the wound area was first detectable in a 5-day-old wound, while all wounds of more than 18 days duration contained a completely reepithelialized wound area. Between 5 and 18 days the basal layer of keratinocytes showed — in contrast to normal skin — only some cells positive for cytokeratin 5. In some, but not all lesions with a wound age of 13 days or more, a basal cell layer completely staining for cytokeratin 5 was demonstrable. This staining pattern was found in all skin wounds with a wound age of more than 23 days. The immunohistochemical detection of cytokeratin 13 which can be observed regularly in non-cornifying squamous epithelia provides no information for the time-estimation of human skin wounds, since no significant temporary expression of this polypeptide seems to occur during the healing of human skin wounds

Adult Neural Stem Cell Regulation by Small Non-coding RNAs: Physiological Significance and Pathological Implications

The adult neurogenic niches are complex multicellular systems, receiving regulatory input from a multitude of intracellular, juxtacrine, and paracrine signals and biological pathways. Within the niches, adult neural stem cells (aNSCs) generate astrocytic and neuronal progeny, with the latter predominating in physiological conditions. The new neurons generated from this neurogenic process are functionally linked to memory, cognition, and mood regulation, while much less is known about the functional contribution of aNSC-derived newborn astrocytes and adult-born oligodendrocytes. Accumulating evidence suggests that the deregulation of aNSCs and their progeny can impact, or can be impacted by, aging and several brain pathologies, including neurodevelopmental and mood disorders, neurodegenerative diseases, and also by insults, such as epileptic seizures, stroke, or traumatic brain injury. Hence, understanding the regulatory underpinnings of aNSC activation, differentiation, and fate commitment could help identify novel therapeutic avenues for a series of pathological conditions. Over the last two decades, small non-coding RNAs (sncRNAs) have emerged as key regulators of NSC fate determination in the adult neurogenic niches. In this review, we synthesize prior knowledge on how sncRNAs, such as microRNAs (miRNAs) and piwi-interacting RNAs (piRNAs), may impact NSC fate determination in the adult brain and we critically assess the functional significance of these events. We discuss the concepts that emerge from these examples and how they could be used to provide a framework for considering aNSC (de)regulation in the pathogenesis and treatment of neurological diseases

Quantum Logic with a Single Trapped Electron

We propose the use of a trapped electron to implement quantum logic operations. The fundamental controlled-NOT gate is shown to be feasible. The two quantum bits are stored in the internal and external (motional) degrees of freedom.Comment: 7 Pages, REVTeX, No Figures, To appear in Phys. Rev.

Effect of Nuclear Quadrupole Interaction on the Relaxation in Amorphous Solids

Recently it has been experimentally demonstrated that certain glasses display an unexpected magnetic field dependence of the dielectric constant. In particular, the echo technique experiments have shown that the echo amplitude depends on the magnetic field. The analysis of these experiments results in the conclusion that the effect seems to be related to the nuclear degrees of freedom of tunneling systems. The interactions of a nuclear quadrupole electrical moment with the crystal field and of a nuclear magnetic moment with magnetic field transform the two-level tunneling systems inherent in amorphous dielectrics into many-level tunneling systems. The fact that these features show up at temperatures $T<100mK$, where the properties of amorphous materials are governed by the long-range $R^{-3}$ interaction between tunneling systems, suggests that this interaction is responsible for the magnetic field dependent relaxation. We have developed a theory of many-body relaxation in an ensemble of interacting many-level tunneling systems and show that the relaxation rate is controlled by the magnetic field. The results obtained correlate with the available experimental data. Our approach strongly supports the idea that the nuclear quadrupole interaction is just the key for understanding the unusual behavior of glasses in a magnetic field.Comment: 18 pages, 9 figure

Deterministic Hydrological Model For Flood Risk Assessment Of Mexico City

Mexico City is facing problems of flooding in some areas at certain times of the year, causing important losses and damages on properties and residents including some casualties. Therefore, it is important to carry out a flood risk assessment in the catchment of Mexico City and estimate damages of probable flood events. However, limited data of observed discharges and water depths in the main rivers of the city are available, and this represents an obstacle for the understanding of flooding in Mexico City. The objective of the developed tool is to provide an efficient support to management of the flood processes by predicting the behavior of the catchment for different rainfall events and flood scenarios. The capability of a model based on MIKE SHE modeling system for the Mexico City catchment was evaluated by comparing the observed data and the simulation results during a year after a careful development based on the most important parameters for characterizing the processes. Significant and operational results (\u3e0.75 for Nash Sutcliffe coefficient) have been obtained on one of the major sub-catchments of the Mexico basin. These results demonstrate the interest to implement a deterministic hydrological model for assessing flood risks in a dense urban environment where data availability is limited. In addition, three methods for flood map creation are proposed to assist flood risk management