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A review of physiology and behaviour–based studies on the function of stereotypic behaviour indicates contradiction and inconsistency within the literature. By considering appropriate neurochemical data alongside an existing model of motivation (Hughes and Duncan, 1988), a greater understanding of the function of stereotypy may be gained. The Hughes and Duncan model (1988), described stereotypies as highly motivated appetitive behaviours performed repeatedly in an environment where consummatory goals are denied. Moreover, appetitive behaviours activate reward circuitry such as the ventral tegmental area and nucleus accumbens and are thus considered to have a reward value associated with their performance (Carr, 2002; Jones et al., 1990). Stress induced sensitisation of reward circuitry may result in appetitive ‘stereotypies’ having increased reward value, perhaps becoming consummatory in their own right. In such a scenario, stereotypic behaviour could function as a coping tool, allowing the animal to counter the effects of an aversive environment.
We give an update of our ongoing survey for intracluster light (ICL), in a sample of distant Abell clusters. We find that the amount of intracluster starlight is comparable to that seen in nearby clusters, and that tidal debris appear to be common.
The aim of this study was to examine the population structure, transmission and spatial relationship between genotypes of Shiga toxin-producing Escherichia coli (STEC) and Campylobacter jejuni, on 20 dairy farms in a defined catchment. Pooled faecal samples (n = 72) obtained from 288 calves were analysed by real-time polymerase chain reaction (rtPCR) for E. coli serotypes O26, O103, O111, O145 and O157. The number of samples positive for E. coli O26 (30/72) was high compared to E. coli O103 (7/72), O145 (3/72), O157 (2/72) and O111 (0/72). Eighteen E. coli O26 and 53 C. jejuni isolates were recovered from samples by bacterial culture. E. coli O26 and C. jejuni isolates were genotyped using pulsed-field gel electrophoresis and multilocus sequence typing, respectively. All E. coli O26 isolates could be divided into four clusters and the results indicated that E. coli O26 isolates recovered from calves on the same farm were more similar than isolates recovered from different farms in the catchment. There were 11 different sequence types of C. jejuni isolated from the cattle and 22 from water. An analysis of the population structure of C. jejuni isolated from cattle provided evidence of clustering of genotypes within farms, and among groups of farms separated by road boundaries.
The Australian Imaging, Biomarkers and Lifestyle (AIBL) Flagship Study of Ageing is a prospective study of 1,112 individuals (211 with Alzheimer's disease (AD), 133 with mild cognitive impairment (MCI), and 768 healthy controls (HCs)). Here we report diagnostic and cognitive findings at the first (18-month) follow-up of the cohort. The first aim was to compute rates of transition from HC to MCI, and MCI to AD. The second aim was to characterize the cognitive profiles of individuals who transitioned to a more severe disease stage compared with those who did not.
Eighteen months after baseline, participants underwent comprehensive cognitive testing and diagnostic review, provided an 80 ml blood sample, and completed health and lifestyle questionnaires. A subgroup also underwent amyloid PET and MRI neuroimaging.
The diagnostic status of 89.9% of the cohorts was determined (972 were reassessed, 28 had died, and 112 did not return for reassessment). The 18-month cohort comprised 692 HCs, 82 MCI cases, 197 AD patients, and one Parkinson's disease dementia case. The transition rate from HC to MCI was 2.5%, and cognitive decline in HCs who transitioned to MCI was greatest in memory and naming domains compared to HCs who remained stable. The transition rate from MCI to AD was 30.5%.
There was a high retention rate after 18 months. Rates of transition from healthy aging to MCI, and MCI to AD, were consistent with established estimates. Follow-up of this cohort over longer periods will elucidate robust predictors of future cognitive decline.
Erythropoietin (EPO) gene therapy can be used for several purposes; however, its effects on reproductive performance are unknown. The aim of this study was to evaluate the toxicological effects of non-viral (EPO) gene transfer on sperm motility, viability, morphology and concentration. Rabbit EPO cDNA was cloned into a pTarget mammalian expression vector. Rabbits were administered with: (1) pTarget/EPO vector, (2) recombinant human EPO (rHuEpo) and (3) saline (control). Both pTarget/EPO and rHuEpo significantly increased (P < 0.05) hematocrit levels 1 week after injection and they remained significantly higher than the control for up to 5 weeks (P < 0.05), showing that both EPO treatments were effective in stimulating the production of red blood cells in rabbits. The EPO gene transfer or rHuEPO administration had no significant effect (P > 0.05) on sperm motility, vigor, viability, concentration or morphology in the testis.
In a previous paper , a theory of fractional integration was developed for certain spaces Fp,μ of generalised functions. In this paper we extend this theory by relaxing some of the restrictions on the various parameters involved. In particular we show how a generalised Erdelyi-Kober operator can be defined on Fʹp,μ for 1 ≦ p ≦ ∞ and for all complex numbers μ except for those lying on a countable number of lines of the form Re μ = constant in the complex μ-plane. Mapping properties of these generalised operators are obtained and several applications mentioned.
This note is concerned with the spaces F'p,µ of generalised functions introduced in a previous paper. A necessary and sufficient condition for an inclusion of the form
to hold is established. The case p = ∞ leads to consideration of a class G''∞µ whose simple properties are noted. Some consequences of relevance to fractional integrals and Hankel transforms are indicated.
In previous papers [11,12,13], certain spaces of generalized functions were studied from the point of view of fractional calculus. In this paper, we show how a Hankel transform Hv of order v can be defined on for all complex numbers v except for those lying on a countable number of lines of the form Re v = constant in the complex v-plane. The mapping properties of Hv on are obtained. Various connections between Hv (or modifications of Hv) and operators of fractional integration are examined.
The theories of fractional calculus and of the Hankel transform developed in for the spaces F′p, μ of generalised functions are used to study distributional analogues of dual integral equations of Titchmarsh type. These are shown to have infinitely many solutions in F′p, μ under very general conditions on the parameters involved. These results are used to study the corresponding classical problem in weighted Lp spaces. Existence and uniqueness of classical solutions are investigated and examples given of both uniqueness and non-uniqueness for the classical problem.
A result for the Erdélyi-Kober operators, mentioned briefly by Buschman, is discussed together with a second related result. The results are proved rigorously by means of an index law for powers of certain differential operators and are shown to be valid under conditions of great generality. Mellin multipliers are used and it is shown that, in a certain sense, the index law approach is equivalent to, but independent of, the duplication formula for the gamma function. Various statements can be made concerning fractional integrals and derivatives which produce, as special cases, simple instances of the chain rule for differentiation and changes of variables in integrals.
The gene expression of Bax, Bcl-2, survivin and p53, following in vitro maturation of equine oocytes, was compared in morphologically distinct oocytes and cumulus cells. Cumulus–oocyte complexes (COC) were harvested and divided into two groups: G1 – morphologically healthy cells; and G2 – less viable cells or cells with some degree of atresia. Total RNA was isolated from both immature and in vitro matured COC and real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to quantify gene expression. Our results showed there was significantly higher expression of survivin (P < 0.05) and lower expression of p53 (P < 0.01) in oocytes compared with cumulus cells in G1. No significant difference in gene expression was observed following in vitro maturation or in COC derived from G1 and G2. However, expression of the Bax gene was significantly higher in cumulus cells from G1 (P < 0.02).
Spherical aberration corrected Atomic Number Contrast Scanning Electron Microscopy (Z-STEM) has recently demonstrated an amazing ability to not only obtain sub-angstrom levels of detail but also yield chemical information at that level as well. With an optimal probe size of 0.8 Å, extremely detailed images of CdSe nanocrystals were obtained showing the lattice structure and surface morphology. As an example of the usefulness of this technique, a sample of CdSe nanocrystals prepared using trioctylphosphine oxide (TOPO) as the surfactant was compared to a sample of CdSe prepared using a mixture of TOPO and hexadecylamine (HDA) as the surfactant. The TOPO/HDA nanocrystals exhibit a narrower size distribution and several orders of magnitude greater fluorescence compared to that of the TOPO only nanocrystals. Interestingly, the Z-STEM images show a striking difference in nanocrystal morphology as the result of the addition of HDA to the reaction mixture. This result suggests surface morphology can be tuned through judicious choice of surfactant. A second example of Z- STEM imaging involves the characterization of CdSe/ZnS core/shell nanocrystals. The mass contrast afforded by Z-STEM can easily distinguish between core and shell.
Exhaust gas heat is the primary source of warming in a conventional automotive exhaust catalyst. It typically becomes operational within minutes after the initial start-up of an engine, when it attains temperatures greater than approximately 350°C. However, around 70% of the total hydrocarbon and carbon monoxide (CO) emissions of a modern gasoline powered vehicle, under a normal driving cycle, are released during this period of cold-start. One of the strategies suggested to treat the pollutants during the first minute after initial start-up involves electrically heating the catalyst. However, devices developed for this purpose are power intensive, can require a second battery and can reduce fuel economy. The increased weight, in turn, results in increased pollution. Here we describe a low power consumption prototype which contains a conducting layer beneath the washcoat. The prototype [4 cm2] was tested at a gas flow rate of 100 seem and required less than 5 Watts to attain temperatures greater than 350°C in less than 10 seconds. The prototype was tested in a flow reactor and found to rapidly heat up to light-off temperatures where the conversion of the hydrocarbons and CO takes place. We also summarize progress made in our laboratory in the fabrication of a test device employing sol-gel processed metal oxide films.
The application of sol-gel processed materials in a variety of sensors has been proposed. We describe microcalorimeter sensor devices employing sol-gel processed alumina based materials which can be used to monitor pollutants in automotive exhaust. These sensors operate by measuring changes in resistance upon catalysis and are economically acceptable for automotive applications. It is important to point out that automobiles will be required to have a means of monitoring exhaust gases by on-board sensors as mandated by the EPA and the California Air Resources Board (OBD-II).