501 research outputs found
The Behaviour of Swine
The pig was a forest-dwelling animal from the beginning of its history. In some parts of the world it has been domesticated for at least 7000 years. The European breeds of domestic swine were derived from the local wild pig, Sus scrofa. Herds ranged in pastures and forests and kept indoors only for fattening. The breeds in the Far East were derived from another wild pig, Sus vittatus, a smaller animal with shorter legs and a higher reproductive ability (Mohr 1960; Zeuner 1963). The two types interbred readily. The modem breeds of pig evolved from different crossings between the two original types. They form a rich diversity of genetic material and more than 200 breeds have been catalogued. Certain wild types of pig-like animals, such as the African bush pig (Pontamochoerus larvatus) and the wart hog (Phacochoerus aethiopecus), have never been domesticated.
The basis of the social structure in feral swine is the matriarchal herd: one or several females with their offspring. The males are not permanently associated to such herds, often ranging solitary or in \u27bachelor\u27 groups (Fig. 52). Under domestication the pig has been modified from a pugnacious, free-ranging, foraging beast to a more docile animal which is handled readily in large groups under conditions of confined rearing. The behavioural plasticity of swine is emphasized by the rapidity with which wild pigs have adapted to rearing in restricted conditions. Although most of our knowledge of the behaviour of swine has been gained from data collected incidentally to research on nutrition, breeding, physiology and management, a number of experimental studies have recently appeared in learning, adaptation, social, sexual and maternal behaviours, making the pig the best known species among domestic mammals, from the point of view of behaviour
Formal Availability Analysis using Theorem Proving
Availability analysis is used to assess the possible failures and their
restoration process for a given system. This analysis involves the calculation
of instantaneous and steady-state availabilities of the individual system
components and the usage of this information along with the commonly used
availability modeling techniques, such as Availability Block Diagrams (ABD) and
Fault Trees (FTs) to determine the system-level availability. Traditionally,
availability analyses are conducted using paper-and-pencil methods and
simulation tools but they cannot ascertain absolute correctness due to their
inaccuracy limitations. As a complementary approach, we propose to use the
higher-order-logic theorem prover HOL4 to conduct the availability analysis of
safety-critical systems. For this purpose, we present a higher-order-logic
formalization of instantaneous and steady-state availability, ABD
configurations and generic unavailability FT gates. For illustration purposes,
these formalizations are utilized to conduct formal availability analysis of a
satellite solar array, which is used as the main source of power for the Dong
Fang Hong-3 (DFH-3) satellite.Comment: 16 pages. arXiv admin note: text overlap with arXiv:1505.0264
Nueva especie de Pseudosinella Schaeffer, 1897 de la PenÃnsula Ibérica (Collembola, Entomobryidae)
A new species of Pseudosinella, P. soriensis sp. n. is described and a new key to worldwide species of the petterseni group, to which the new species belongs, is made.Se describe una nueva especie de Pseudosinella de la PenÃnsula Ibérica, P. soriensis sp. n., al mismo tiempo que se da una clave de todas las especies del grupo petterseni, al que pertenece la especie
The Value of Suction Drainage Fluid Culture during Aseptic and Septic Orthopedic Surgery: A Prospective Study of 901 Patients
There are no guidelines on the value of suction drainage fluid culture (SDC), and it is difficult to determine whether the organisms cultured from suction drainage fluid samples are pathogenic or simply contaminants. We performed 2989 cultures of suction drainage fluid samples obtained, during a 1-year period, from 901 patients who underwent aseptic or septic orthopedic surgery (946 operations). The culture results were analyzed to evaluate their ability to detect postoperative infection after aseptic operations or to detect either a persistent or new episode of sepsis in patients known to have infection. For aseptic operations, the sensitivity of SDC was 25%, the specificity was 99%, the positive predictive value was 25%, and the negative predictive value was 99%. For septic operations, the sensitivity of SDC was 81%, the specificity was 96%, the positive predictive value was 87%, and the negative predictive value was 94%. We conclude that, for aseptic orthopedic surgery, SDC is not useful in detecting postoperative infection. However, for septic orthopedic surgery, it is of clinical importanc
The "Ram Effect": A "Non-Classical" Mechanism for Inducing LH Surges in Sheep
During spring sheep do not normally ovulate but exposure to a ram can induce ovulation. In some ewes an LH surge is induced immediately after exposure to a ram thus raising questions about the control of this precocious LH surge. Our first aim was to determine the plasma concentrations of oestradiol (E2) E2 in anoestrous ewes before and after the "ram effect" in ewes that had a "precocious" LH surge (starting within 6 hours), a "normal" surge (between 6 and 28h) and "late» surge (not detected by 56h). In another experiment we tested if a small increase in circulating E2 could induce an LH surge in anoestrus ewes. The concentration of E2 significantly was not different at the time of ram introduction among ewes with the three types of LH surge. "Precocious" LH surges were not preceded by a large increase in E2 unlike "normal" surges and small elevations of circulating E2 alone were unable to induce LH surges. These results show that the "precocious" LH surge was not the result of E2 positive feedback. Our second aim was to test if noradrenaline (NA) is involved in the LH response to the "ram effect". Using double labelling for Fos and tyrosine hydroxylase (TH) we showed that exposure of anoestrous ewes to a ram induced a higher density of cells positive for both in the A1 nucleus and the Locus Coeruleus complex compared to unstimulated controls. Finally, the administration by retrodialysis into the preoptic area, of NA increased the proportion of ewes with an LH response to ram odor whereas treatment with the α1 antagonist Prazosin decreased the LH pulse frequency and amplitude induced by a sexually active ram. Collectively these results suggest that in anoestrous ewes NA is involved in ram-induced LH secretion as observed in other induced ovulators
Exploring a Gemcitabine-Glucose Hybrid as a Glycoconjugate Prodrug
Nucleoside analogues are established treatments for cancer and viral infection. Gemcitabine is a commonly employed nucleoside analogue displaying anticancer properties against a range of tumor types but is rapidly inactivated in vivo. Efforts to bolster its pharmaceutical profile include investigating prodrug forms. Herein, we explore the synthesis of a novel glucose-gemcitabine glycoconjugate, targeting uptake via glucose transport. We select a redox-reactive disulfide linker for conjugation of gemcitabine (through N4-cytosine) with glucose. Evaluation of this glycoconjugate reveals increased toxicity against androgen insensitive PC3 prostate cancer cells compared to LNCaP (which have lower levels of glucose transporter GLUT1). These preliminary results suggest that glycoconjugation of nucleosides may be an effective approach to targeting cells which display increased uptake and metabolism of glucose
Transactivation of EGFR by LPS induces COX-2 expression in enterocytes
Necrotizing enterocolitis (NEC) is the leading cause of gastrointestinal morbidity and mortality in preterm infants. NEC is characterized by an exaggerated inflammatory response to bacterial flora leading to bowel necrosis. Bacterial lipopolysaccharide (LPS) mediates inflammation through TLR4 activation and is a key molecule in the pathogenesis of NEC. However, LPS also induces cyclooxygenase-2 (COX-2), which promotes intestinal barrier restitution through stimulation of intestinal cell survival, proliferation, and migration. Epidermal growth factor receptor (EGFR) activation prevents experimental NEC and may play a critical role in LPS-stimulated COX-2 production. We hypothesized that EGFR is required for LPS induction of COX-2 expression. Our data show that inhibiting EGFR kinase activity blocks LPS-induced COX-2 expression in small intestinal epithelial cells. LPS induction of COX-2 requires Src-family kinase signaling while LPS transactivation of EGFR requires matrix metalloprotease (MMP) activity. EGFR tyrosine kinase inhibitors block LPS stimulation of mitogen-activated protein kinase ERK, suggesting an important role of the MAPK/ERK pathway in EGFR-mediated COX-2 expression. LPS stimulates proliferation of IEC-6 cells, but this stimulation is inhibited with either the EGFR kinase inhibitor AG1478, or the selective COX-2 inhibitor Celecoxib. Taken together, these data show that EGFR plays an important role in LPS-induction of COX-2 expression in enterocytes, which may be one mechanism for EGF in inhibition of NEC
The "ram effect": new insights into neural modulation of the gonadotropic axis by male odors and socio-sexual interactions
Reproduction in mammals is controlled by the hypothalamo-pituitary-gonadal (HPG) axis under the influence of external and internal factors such as photoperiod, stress, nutrition, and social interactions. Sheep are seasonal breeders and stop mating when day length is increasing (anestrus). However, interactions with a sexually active ram during this period can override the steroid negative feedback responsible for the anoestrus state, stimulate LH secretion and eventually reinstate cyclicity. This is known as the ram effect and research into the mechanisms underlying it is shedding new light on HPG axis regulation. The first step in the ram effect is increased LH pulsatile secretion in anestrus ewes exposed to a sexually active male or only to its fleece, the latter finding indicating a pheromone-like effect. Estradiol secretion increases in all ewes and this eventually induces a LH surge and ovulation, just as during the breeding season. An exception is a minority of ewes that exhibit a precocious LH surge (within 4h) with no prior increase in estradiol. The main olfactory system and the cortical nucleus of the amygdala are critical brain structures in mediating the ram effect since it is blocked by their inactivation. Sexual experience is also important since activation (increased c-fos expression) in these and other regions is greatly reduced in sexually naïve ewes. In adult ewes kisspeptin neurons in both arcuate and preoptic regions and some preoptic GnRH neurons are activated 2h after exposure to a ram. Exposure to rams also activates noradrenergic neurons in the locus coeruleus and A1 nucleus and increased noradrenalin release occurs in the posterior preoptic area. Pharmacological modulation of this system modifies LH secretion in response to the male or his odor. Together these results show that the ram effect can be a fruitful model to promote both a better understanding of the neural and hormonal regulation of the HPG axis in general and also the spe
Towards a 'clicked' PSMA targeting gene delivery bioconjugate-polyplex for prostate cancer
Prostate cancer is the most common cancer in men in the UK with over 50 000 new cases diagnosed each year and although therapeutic advances in surgery, anti-androgens, radio- and chemotherapy have increased survival rates, there still remains a need for new treatments to combat the most aggressive forms of the disease. Gene therapy offers promise as an alternative approach but is reliant on selective targeting to the cancer cell surface. Herein we describe the novel construction of a prostate specific membrane antigen (PSMA) binding bioconjugate-polyplex, based on a glutamate-urea peptide scaffold using 'click' chemistry, which we demonstrate is capable of targeted delivery of a GFP gene to PSMA overexpressing prostate cancer cells, and therefore may have potential future application as part of a prostate cancer gene delivery therapy
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