15,363 research outputs found

    Vacuum Decay: Erasing the Universe

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    Modulated Oscillations in Three Dimensions

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    The analysis of the fully three-dimensional and time-varying polarization characteristics of a modulated trivariate, or three-component, oscillation is addressed. The use of the analytic operator enables the instantaneous three-dimensional polarization state of any square-integrable trivariate signal to be uniquely defined. Straightforward expressions are given which permit the ellipse parameters to be recovered from data. The notions of instantaneous frequency and instantaneous bandwidth, generalized to the trivariate case, are related to variations in the ellipse properties. Rates of change of the ellipse parameters are found to be intimately linked to the first few moments of the signal's spectrum, averaged over the three signal components. In particular, the trivariate instantaneous bandwidth---a measure of the instantaneous departure of the signal from a single pure sinusoidal oscillation---is found to contain five contributions: three essentially two-dimensional effects due to the motion of the ellipse within a fixed plane, and two effects due to the motion of the plane containing the ellipse. The resulting analysis method is an informative means of describing nonstationary trivariate signals, as is illustrated with an application to a seismic record.Comment: IEEE Transactions on Signal Processing, 201

    Critical factors in the teaching of Japanese in New Zealand at years 7 and 8 : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Second Language Teaching at Massey University

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    Current literature about the teaching of Japanese in New Zealand has raised a number of issues. However, there has been no attempt made to rank these issues either in terms of priority or in terms of how they may be addressed. In addition, in the existing literature, the writers have not provided any solutions or recommendations themselves. This research identifies and ranks issues in Japanese language teaching programmes at Years 7 and 8 in the New Zealand school setting. Two professional groups (teachers and principals) were approached to provide the data. Discussions were held in focus groups with teachers of Japanese from around New Zealand. Issues which either constrain or facilitate the implementation of a Japanese language teaching programme were elicited from participating teachers. These issues have been termed "factors" to avoid any negative connotations. Professional responses to the most critical factors were also sought from the teachers. The critical factors generated by teachers were grouped into four broad categories and the focus groups then contributed professional responses to these. Initial results showed that teachers identified "commitment from principal", "pressure and time" and "availability of resources" as being important. Questionnaires were then developed and sent to principals in schools offering Japanese at these levels. Principals identified "commitment from principal", "availability of resources" and "confidence of teachers" as being important. The results of this study are discussed with reference to the current literature and a number of implications for teaching programmes are proposed. These suggestions are intended to guide schools contemplating the introduction of Japanese or another international language at these levels. The model developed for group discussions could be used in further research when trying to determine critical factors in the teaching of either other languages or indeed other curriculum areas

    Hyaluronan-CD44 interaction promotes microRNA signaling and RhoGTPase activation leading to tumor progression.

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    A hallmark of all solid tumor malignancies is the ability to invade the surrounding tissue and/or metastasize to distant sites. Tumors cells have altered signaling pathways which that to cytoskeleton activation and migration. Myriad studies have attempted to identify specific adhesion molecule(s) expressed in solid tumor cells that correlate with tumor cell migrative and invasive behaviors. Among such candidate molecules is hyaluronan (HA), the major glycosaminoglycan component of extracellular matrix (ECM). HA serves not only as a primary constituent of connective tissue extracellular matrices but also functions as a bio-regulatory molecule. Pertinently, HA is enriched in many types of tumors. HA is capable of binding to CD44 which is a ubiquitous, abundant and functionally important receptor expressed on the surface of many normal cells and tumor cells. Several lines of evidence indicate that CD44 selects its unique downstream effectors and coordinates downstream, intracellular signaling pathways that influence multiple cellular functions. Certain microRNAs [(miRNAs), small RNA molecules with ~20-25 nucleotides] have been shown to play roles in regulating tumor cell migration, invasion, survival and chemotherapy resistance. In this article, a special focus is placed on the role of HA-mediated CD44 interaction with unique signaling molecules in activating intracellular miRNA-signaling and RhoGTPase functions leading to the concomitant onset of tumor cell activities (e.g., tumor cell migration, invasion, survival and chemoresistance) and tumor progression. This new knowledge could serve as groundwork for the future development of new drug targets to inhibit HA/CD44-mediated oncogenic signaling and cancer progression

    The effects of partial stable confinement on the voluntary activity of weanling thoroughbred foals : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science, Massey University, Palmerston North, New Zealand

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    This thesis discusses an observational study, which evaluates the effects of partial stable confinement on the voluntary activity of weanling Thoroughbreds kept at pasture. Despite the current knowledge identifying the need for early exercise and pasture access in young Thoroughbreds, there is little information on pasture activity, and none on the effects of partial stable confinement on the amount of, and type of, activity when at pasture. It has previously been stated that young horses confined to a stable at night, spend more time cantering and trotting in the paddock during the day, when compared to their unconfined counterparts- the authors suggested this may be compensation for the lack of activity carried out whilst in confinement. Unfortunately, no further research has been carried out to support this theory, and it is therefore unknown how much confinement is required before horses will carry out compensatory activity, and how length of confinement and the subsequent volume of compensatory activity may affect total average daily activity. A study was carried out on a small commercial Thoroughbred stud farm in the Manawatu, to determine the effects of partial stable confinement on the amount, and type of activity six weanling Thoroughbreds carried out on a daily basis. The horse’s remained under normal management conditions, and were kept at pasture, and confined in loose boxes for an average of three hours a day, on mornings decided by the Stud Master, for handling and yearling sales preparation. Activity was monitored for 141 days using a Heyrex biosensor. The sensor containing a tri-axial accelerometer was attached to each horse’s halter, and the data were recorded as Delta-G; the change in acceleration between respective samples. The data were recorded in 15 minute increments, resulting in approximately 576 records per day and possible 13,536 data points per horse (there was a range of 3,456 - 10,272 usable data points per horse). A total of 39,372 15-minute data points were used in the data analysis. Each horse’s activity profile, including total daily activity, average daily activity and proportion of highand low-energy activity, when at pasture and during confinement was analysed. Total average daily activity varied between horses (70,385 – 95,331, P<0.001), however each horse’s total daily activity was highly repeatable across days with no significant difference between horses between days. Partial confinement resulted in a reduction in average daily activity in all horses (67,682 – 84,737, P<0.0088), except Colt 3 who was more active during days of confinement, than on days of no confinement (89903±5073 and 84813±2163, respectively). Partial stable confinement had no significant effect on the proportion of total activity which was highenergy activity (8.69% on days of confinement, vs 12.23% on days of no confinement) except for Colt 3, who carried out a high proportion of high-energy activity during a day of confinement, then on a day of no confinement (18.23% vs 9.14% respectively). This may be a form of compensation, however it was only noted in one horse, and therefore is more likely to be a behavioural response to being isolated to a stable. The proportion of high-energy activity between the hours of 9am-12pm, when confinement would occur, was also not effected by confinement when compared to days of no confinement (8.64% vs 9.80%, respectively), except in Colt 2, who carried out no high-energy activity whilst in confinement between 9am-12pm. The partial confinement of these weanlings appeared to reduce their overall average daily activity, however it did not affect the amount of high-energy activity. Thus partial confinement may not restrict the all-important osteo-inductive high speed activity required to promote optimal musculoskeletal development in weanlings. However, we lacked the experimental design to examine if there was any association of length of confinement and any compensatory activity. Further studies should examine if the length of partial confinement alters the subsequent activity at pasture

    Live transplantation in children with biliary atresia and vascular anomalies

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    Eight of 29 infants and children undergoing orthotopic liver transplantation for extrahepatic biliary atresia had associated major vascular anomalies. A distinctive and highly unusual vascular malformation consisting of absent inferior vena cava, anomalous origin of the hepatic artery, and preduodenal portal vein was encountered in three of these children. Although at times technically difficult, single anomalies of hepatic vasculature were satisfactorily handled. In contrast, transplantation attempts were lethal in all three infants having the complex vascular malformation. The suggestion is made that this specific subgroup of patients with biliary atresia be identified in advance and that, at the moment, children with this composite anomaly are highly questionable candidates for liver transplantation. © 1974

    Operative implications of preduodenal portal vein

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