bluuebunny/crossref_metadata_2025 huggingface dataset:
Wavenumber‐4 patterns of the total electron content over the low latitude ionosphere
Authors: Wan W. , Liu L. , Pi X. , Zhang M.‐L. , Ning B. , Xiong J. , Ding F.
Published: June 2008

The global ionospheric maps (GIMs) produced by JPL are used to investigate the longitudinal structure of the low latitude ionosphere. As a proxy of the ionization parameter at low latitudes, the latitudinally integrated total electron content (ITEC) is first extracted from low latitude GIMs and then Fourier filtered to obtain the wavenumber‐4 components. We then study in detail the diurnal, seasonal and solar cycle variations of the wave patterns. It is found that the wavenumber‐4 patterns are intense and well developed in boreal summer and early boreal autumn, but quite weak in boreal winter. This seasonal variation is consistent with that of the zonal wind of the non‐migrating tide mode DE3. We also found that the wavenumber‐4 patterns shift eastward with a shifting speed that is smaller in daytime than at night. This is attributed to the contribution of both the eastward propagation of DE3 in E‐region and the zonal E ×B ion drifts in F‐region. Our results support the suggestion that the longitudinal wavenumber‐4 structure of the low latitude ionosphere should be originated from the non‐migrating tide mode DE3.
Polyglutamylation: a fine‐regulator of protein function?
Authors: Janke Carsten , Rogowski Krzysztof , van Dijk Juliette
Published: June 2008

Polyglutamylation is a post‐translational modification in which glutamate side chains of variable lengths are formed on the modified protein. It is evolutionarily conserved from protists to mammals and its most prominent substrate is tubulin, the microtubule (MT) building block. Various polyglutamylation states of MTs can be distinguished within a single cell and they are also characteristic of specific cell types or organelles. Polyglutamylation has been proposed to be involved in the functional adaptation of MTs, as it occurs within the carboxy‐terminal tubulin tails that participate directly in the binding of many structural and motor MT‐associated proteins. The discovery of a new family of enzymes that catalyse this modification has brought new insight into the mechanism of polyglutamylation and now allows for direct functional studies of the role of tubulin polyglutamylation. Moreover, the recent identification of new substrates of polyglutamylation indicates that this post‐translational modification could be a potential regulator of diverse cellular processes.
Experimental observations and modeling of nanoparticle formation in laser-produced expanding plasma
Authors: Lescoute E. , Hallo L. , Hébert D. , Chimier B. , Etchessahar B. , Tikhonchuk V. T. , Chevalier J.-M. , Combis P.
Published: June 2008

Interaction of a laser beam with a target may generate a high velocity expanding plasma plume, solid debris, and liquid nano- and microparticles. They can be produced from plasma recombination, vapor condensation or by a direct expulsion of the heated liquid phase. Two distinct sizes of particles are observed depending on the temperature achieved in the plasma plume: Micrometer-size fragments for temperatures lower than the critical temperature, and nanometer-size particles for higher temperatures. The paper presents experimental observations of fragments and nanoparticles in plasma plumes created from gold targets. These results are compared with theoretical models of vapor condensation and microparticle formation.
Mixing efficiency in high-aspect-ratio Rayleigh–Taylor experiments
Authors: Dalziel Stuart B. , Patterson Michael D. , Caulfield C. P. , Coomaraswamy Imran A.
Published: June 2008

High-Reynolds-number turbulence generated by Rayleigh–Taylor instability is known to be much more efficient at mixing density-stratified fluids than mixing driven by most other mechanisms. We demonstrate here that the final state of the instability in a high-aspect-ratio environment is uniform, corresponding to the maximum mixing efficiency possible. The efficiency of the mixing appears to be constant throughout the evolution of the flow, despite the flow changing from being inertially dominated with a high-Reynolds-number initial growth of the mixing zone, to a viscously dominated late-time decay. The initial growth, in which vertical transport takes the form of a turbulent diffusion, is characterized by a t2∕5 power law, indicating that the diffusivity is not constant but rather decreases as the strength of the unstable density gradient driving the flow decreases. As the unstable stratification is reduced, inertia begins to play a lesser role with molecular viscosity taking over the controlling dynamics, but with vertical transport still dominated by parcels of fluid needing to pass around many vortexlike structures during the exponential decay toward the well-mixed final state.
Study of interface barrier of SiNx/GaN interface for nitrogen-polar GaN based high electron mobility transistors
Authors: Nidhi  , Rajan Siddharth , Keller Stacia , Wu Feng , DenBaars Steven P. , Speck James S. , Mishra Umesh K.
Published: June 2008

The SiNx/GaN interface barrier height for N-polar GaN based metal-insulator-semiconductor high electron mobility transistors (MISHEMTs) was investigated. N-polar SiNx/GaN/AlGaN/GaN MISHEMT structures with different GaN cap thicknesses were grown by metal-organic chemical vapor deposition. The properties of the SiNx/GaN interface are of critical importance to device operation and modeling in these devices. An analytical expression for the pinch-off voltage of the HEMT was obtained, and capacitance-voltage (C-V) measurements with different Schottky metals were used to extract the barrier height. The Fermi level at the interface was found to be pinned at approximately 1 eV with respect to GaN conduction band edge, irrespective of the work function of the gate metal. Hall measurements of the two-dimensional electron gas density were found to corroborate the predicted interface barrier height. An approximate value for interface charge causing this pinning was calculated to be 4.5×1012 cm−2.
Auditory Feedback Influences Perceived Driving Speeds
Authors: Horswill Mark S , Plooy Annaliese M
Published: June 2008

Reducing the level of internal noise is seen as a goal when designing modern cars. One danger of such a philosophy is that one is systematically attempting to alter one of the cues that can be used by drivers to estimate speed and this could bias speed judgments and driving behaviour. Seven participants were presented with pairs of video-based driving scenes and asked to judge whether the second scene appeared faster or slower than the first (2-alternative forced-choice task using the method of constant stimuli). They either heard in-car noise at the level it occurred in the real world or reduced in volume by 5 dB. The reduction in noise led to participants judging speeds to be significantly slower and this effect was evident for all participants. This finding indicates that, when in-car noise is attenuated, drivers are likely to underestimate their speed, potentially encouraging them to drive faster and placing them at greater risk of crashing.
Perceptual Deterioration is Reflected in the Neural Response: Fmri Study of Nappers and Non-Nappers
Authors: Mednick Sara C , Drummond Sean P A , Arman A Cyrus , Boynton Geoffrey M
Published: June 2008

Repeated training on a perceptual task can result in performance deterioration. In the case of vision, this practice-dependent decrease, or perceptual deterioration is restored by changing the target orientation, spatial location, or by taking a daytime nap. Behavioral studies suggest the locus of these performance changes to be primary visual cortex. We used fMRI to directly probe whether perceptual deterioration and nap-dependent maintenance of performance can be detected at the level of primary visual cortex. We also asked whether these changes are due to a bottom–up, stimulus-driven response or a top–down plasticity of attentional mechanisms. Subjects were scanned while performing a texture-discrimination task. Half the subjects took a nap between sessions. We measured the relationship between changes in performance and changes in BOLD signal modulation between the two groups. Non-nappers showed performance deterioration that was significantly correlated with decreased BOLD signal modulation, exclusively in area V1 and limited to the bottom–up condition. In contrast, no change was detected in performance and BOLD response in the two conditions for nappers. These results indicate that napping prevented performance deterioration, which was reflected in the fMRI response of neurons in V1. Without a nap, perceptual deterioration was related to decreases in the stimulus-driven, bottom–up representation, rather than decreases in attentional modulation to the stimulus.
Dag score is negatively correlated with breech bareness score of sheep
Authors: Scobie D. R. , O'Connell D. , Morris C. A. , Hickey S. M.
Published: June 2008

At weaning in two consecutive years, traditional Romney and composite lambs (crosses with East Friesian and Texel; n = 3254) were observed on a conventional farm and Perendale and composite lambs (crosses with Texel, Wiltshire and small numbers of Finnish Landrace; n = 2095) were observed on an organic farm. Both were ram breeding farms recording pedigree and performance, and the composite breeds were developed from, and run with, the original flock on each farm. Breech bareness was scored on the lambs between 80 and 120 days of age on a scale from 1, with wool right to the edge of the anus, to 5, where a large bare area surrounded the perineum. Dag score was recorded on a 0–5 scale where an increasing score indicated more dags. Within farms, mean dag score was more pronounced in traditional Romney (1.2) than in composite lambs (0.4), and Perendales were more daggy (1.3) than composite lambs (0.7) across both years (P < 0.001). Dag score was phenotypically correlated with breech bareness score on the Romney farm (−0.18 ± 0.02) and Perendale farm (−0.27 ± 0.03). Combining data from both flocks, heritabilities of breech bareness score (0.55 ± 0.04) and dag score (0.41 ± 0.05) were high, and a strong genetic correlation was observed between the two traits (−0.59 ± 0.07). Mean dag score of ram lambs was greater than ewe lambs (0.8 v. 0.7, P < 0.001) and lambs reared as twins were more daggy than singles (0.8 v. 0.7, P = 0.008). Composite sheep have been adopted throughout New Zealand for the advantages they deliver in lamb production, but through breech bareness they also provide an opportunity to limit dag production and thereby improve both welfare and profitability. Genetically increased breech bareness and decreased dagginess could be used in Australia as alternatives to mulesing.
Mid-pregnancy shearing of autumn-lambing ewes in New Zealand
Authors: deNicolo G. , Kenyon P. R. , Morris S. T. , Morel P. C. H. , Wall A. J.
Published: June 2008

The aim of the present experiment was to ascertain if mid-pregnancy shearing of autumn-lambing ewes would increase the birthweight of the lambs. Following pregnancy diagnosis, 123 pregnant ewes were randomly allocated to one of two treatment groups. One group was shorn on day 74 of pregnancy (P74) and both treatment groups were managed as one mob. Ewe liveweights were recorded on day 53 of pregnancy (P53), day 141 of pregnancy (P141), and 45 (L45) and 75 days (L75) after the start of the lambing period. Lamb liveweights were recorded within the first 24 h of birth, L45 and L75. In addition, girth circumference, crown–rump length, fore leg length and rear leg length were measured within the first 24 h of birth. Ewe liveweight, inclusive of the removed fleece, did not differ between treatment groups at P53, P141, L45 or L75. Lambs born to shorn ewes were heavier at birth compared with lambs born to unshorn ewes (P < 0.05; 4.56 v. 4.24, respectively), but not at L45 or L75. Girth circumference (P < 0.01), crown–rump length (P < 0.05) and fore leg length (P < 0.01) were also longer in lambs born to shorn ewes. It was concluded that ewes shearing ewes in the summer–autumn period can be used as a means of increasing lamb birthweight.
Metabolic profile and oxidative status in goats during the peripartum period
Authors: Celi Pietro , Di Trana Adriana , Quaranta Angelo
Published: June 2008

The aim of this study was to monitor the metabolic profile and oxidative status in goats during the peripartum period. A blood sample was taken from 10 Red Syrian goats on days −21, −3, +1, +14, and +28 from delivery. Samples were assayed for glutathione peroxidase and superoxide dismutase activities, and reactive oxygen metabolites, insulin, insulin-like growth factor-I, free triiodothyronine (fT3), free thyroxine (fT4), leptin, urea, non-esterified fatty acids, triglycerides, cholesterol, total protein, albumin, globulin, calcium and inorganic phosphorus concentrations. Blood glutathione peroxidase activity decreased during the postpartum period and its values were significantly (P < 0.05) lower on days 14 and 28 postpartum. Albumin levels were significantly (P < 0.05) lower on days −3, 1 and 28 from delivery compared with day −21. Plasma urea levels significantly (P < 0.001) decreased starting from day −3 from delivery. No effect of time from delivery was noted on reactive oxygen metabolites, non-esterified fatty acids, triglycerides, cholesterol, total protein, calcium and inorganic phosphorus, insulin and leptin concentrations and superoxide dismutase activity. Plasma concentrations of fT3 were significantly (P < 0.01) higher on days 14 and 28 compared with days −21, −3 and 1 from delivery. Plasma levels of fT4 were significantly (P < 0.01) lower on days −3 and 1 from delivery. Plasma insulin-like growth factor-I values slowly decreased during the postpartum period and its values were significantly (P < 0.05) lower on day 28. This study indicates that goats experienced moderate oxidative stress during the peripartum period.
Understanding interactions between forages and concentrates is important for formulating feeding strategies for growing cattle in central Vietnam
Authors: Doyle P. T. , Stockdale C. R. , Ba Nguyen Xuan , Van Nguyen Huu , Ngoan Le Duc
Published: June 2008

Three experiments were conducted in Vietnam to measure responses in forage intake and diet digestibility to concentrate feeding in growing cattle. The basal diet in all experiments was grass (elephant grass, Pennisetum purpureum, in experiments 1 and 2; native grass in experiment 3) fed at 1.25% liveweight (DM basis) during the day and rice straw fed ad libitum at night. The concentrate in experiment 1 was cassava powder plus urea. In experiments 2 and 3, a formulated concentrate comprised of maize, rice bran, fish meal, urea and salt was used. The concentrates were offered at ~0.3, 0.7, 1.3 and 2.0% liveweight in each experiment, and a zero concentrate treatment was also included. Effects of the amount of concentrate on substitution rate of concentrate for forage and on diet neutral detergent fibre (NDF) digestibility were measured to assess interactions between feeds. Substitution rate was high (0.5–0.7 kg DM reduction in forage intake per kg DM supplement consumed) and not affected by amount of supplement fed in experiment 1. In experiments 2 and 3, there was no substitution at the lowest intake of supplement, but it subsequently increased with amount of supplement consumed, to a high of 0.3–0.5 kg DM reduction in forage intake per kg DM supplement consumed. The cassava powder supplement markedly decreased dietary NDF digestibility (from 62 to 41%), whereas the formulated concentrate only reduced NDF digestibility by 11 and 8% units in experiments 2 and 3, respectively. It was calculated that depressions in NDF digestibility would reduce the estimated metabolisable energy content of the basal forage by 1–3.6 MJ/kg DM at the higher supplement intakes. The importance of these results in making decisions on tactical feeding systems to fatten cattle in central Vietnam is discussed.
Approaches for assessing some attributes of feed-base systems in mixed farming enterprises
Authors: Bell Lindsay W. , Robertson Michael J. , Revell Dean K. , Lilley Julianne M. , Moore Andrew D.
Published: June 2008

Improving the feed-base to better balance livestock demands with the variation in feed supply can improve the sustainability and productivity of livestock enterprises. This paper outlines some approaches and tools that can be applied to the assessment of new feed options and/or potential changes to the feed-base in mixed farming systems. Demonstrations of strategic aspects of designing feed systems include: whole-farm feed planning using simple tools, such as the MLA Feed Demand Calculator, that enable iterative changes to the balance between feed supply and demand to be considered simultaneously; assessing production and environmental risks of different feed-base systems using simulation models (e.g. APSIM, GRAZPLAN); and using bio-economic models (e.g. MIDAS) to investigate the impact of a new feed source on whole-farm profitability and the optimal balance of other feed sources and livestock production system. Also included is an example of an approach to identifying opportunities and seasonal triggers for a tactical response for utilising an alternate feed source (e.g. grazing a grain crop). The importance of economics and risk as factors for assessing feed-base systems is demonstrated. In particular, the marginal value of extra feed supply is a critical element driving the whole-farm economics of the feed system. Some approaches consider seasonal averages, but the risk of year-to-year and within-year variations in the timing and amount of feed supply should also be assessed. Several tools of varying complexity exist to investigate attributes of the feed-base, but it is important that the correct approach is applied to the particular question in mind. A range of approaches could be applied concurrently to fully explore a range of aspects of the performance of a feed-base system.
Manipulating dietary preference to improve animal performance
Authors: Edwards G. R. , Parsons A. J. , Bryant R. H.
Published: June 2008

This paper reviews opportunities to improve the diet quality, intake and performance of animals through manipulation of the partial preference commonly shown by grazing animals for different pasture components. Using evidence from the well-worked example of grass–legume pastures, potential opportunities to manipulate preference are highlighted, including: (i) altering plant characteristics to change the relative preference of alternative species or cultivars; (ii) utilising variation in preference among and within animal species; and (iii) working with, rather than against, known preference patterns, by offering forages as spatially separated monocultures within the same paddock or at different times of the day. In all cases, it is argued that is important to consider the full complexities of pasture–animal interactions, in particular, how current diet choices feed back to determine choices available subsequently in the pasture. To develop feeding systems where desirable pasture traits for animal performance are sustained at a high abundance in the diet, plant and animal breeding selection practises and grazing management systems should take greater account of the existence of partial preferences.
In utero effects on livestock muscle development and body composition
Authors: Brameld John M. , Daniel Zoe C. T. R.
Published: June 2008

This review will focus on the evidence for in utero effects on development of skeletal muscle in farm and laboratory animals, particularly sheep and pigs. We will describe genetic and environmental factors that have been shown to alter the numbers of muscle fibres formed and outline our working hypothesis for the mechanism involved and the critical window during pregnancy when these effects are seen. We will then discuss the long-term consequences in terms of body composition. Although this review concentrates on skeletal muscle development, the mechanism we suggest might be equally applicable to other tissues in the body (e.g. the brain, kidneys or sex organs) and, therefore, impact on their physiological functions.
Responses to grain:sunflower meal supplements by weaned calves grazing mature pasture or eating hay in pens
Authors: Dove H. , Freer M. , Axelsen A. , Donnelly J. R.
Published: June 2008

In southern Australia, winter-born calves may not be at marketable weights until 18 months of age and can thus compete with their dams and the next crop of calves for the pasture resource. We investigated supplementary feeding options to improve calf liveweight gains and overcome this problem. Weaned beef calves confined to feedlots for 70 days were fed different ratios (1 : 1 up to 1 : 4) of sunflower meal to oat grain (Experiment 1) or barley grain (Experiment 2) at levels of 3–6 kg air-dry/day, plus either oaten hay (Expt. 1) or pasture hay (Expt. 2) fed ad libitum. Liveweight gains at 3 kg supplement/day were ~1.2 kg/day at all ratios and were slightly higher at the higher feeding levels. The intake of hay varied inversely with the amount of supplement fed and substitution rates were 0.49 with oaten hay and 0.47 with pasture hay. Total DM intakes did not decline in Experiment 1 as supplement intake increased and increased in Experiment 2 with increasing supplement intake.
A separate group of calves that had been grazing mature pasture while their cohorts were in the feedlot showed good compensatory growth when transferred to good pasture, whereas calves coming out of the feedlot onto the same pasture initially lost weight before regaining weight. This suggests that such feedlot-reared calves should be sold direct from the feedlot.
In a third experiment, over 2 years, weaned calves grazed mature summer pasture for 81 days and were fed 0, 1, 2, 3 or 5 kg/day of a 1 : 2 ratio of sunflower meal : hammer-milled oat grain. Weight gains were less than in Experiments 1 and 2 and responses of gain to supplement intake were curvilinear. Gains did not exceed 0.75 kg/day and peaked at supplement intakes of 4.3 and 2.8 kg DM/day in years 1 and 2, respectively.
Liveweight gains/kg supplement consumed were similar to those in previous studies. A preliminary assessment of supplement costs and the economic value of liveweight gain showed a curvilinear response to supplement intake and suggested that the greatest economic return resulted from an intake of 1.9–2.4 kg/day of the supplement, lower than the supplement intakes for maximum liveweight gain.
Climate change and Australian livestock systems: impacts, research and policy issues
Authors: Howden S. M. , Crimp S. J. , Stokes C. J.
Published: June 2008

The recent changes in Australia’s climate, the likelihood of further changes over the next decades to centuries, and the likely significant impacts of these changes on the Australian livestock industries, provide increasing urgency to explore adaptation options more effectively. Climate and atmospheric changes are likely to impact on the quantity and reliability of forage production; forage quality; thermal stress on livestock; water demands for both animal needs and for growing forage; pest, disease and weed challenges; land degradation processes; and various social and economic aspects including trade. Potential adaptation options are available for moderate climate changes, with these often being variations of existing climate risk management strategies. However, to date there are few Australian examples where these adaptations have been assessed systematically on any scale (e.g. enterprise, regional, whole of industry or national). Nor have many studies been undertaken in a way that (i) effectively harness industry knowledge, (ii) undertake climate change analyses in the framework of existing operational systems, or (iii) assess climate change in the context of other socioeconomic or technical changes. It is likely that there are limits to the effectiveness of existing adaptations under more severe climate changes. In such cases more systemic changes in resource allocation need considering, such as targeted diversification of production systems and livelihoods. Dealing with the many barriers to effective adaptation will require ‘mainstreaming’ climate change into policies covering a range of scales, responsibilities and issues. This mainstreaming will facilitate the development of comprehensive, dynamic and long lasting policy solutions. The integrative nature of climate change problems requires science to include integrative elements in the search for solutions: a willingness to apply integrated rather than disciplinary science and a strengthening of the interface with decision-makers.
Preliminary indications that Merino sheep graze different areas on cooler days in the Southern Rangelands of Western Australia
Authors: Thomas Dean T. , Wilmot Matt G. , Alchin Mark , Masters David G.
Published: June 2008

High ambient temperature can decrease weight gain in livestock, but domestic livestock in extensive grazing systems may have some capacity to adjust their behaviour to reduce the impact of periods of high temperature. We hypothesised that sheep grazing in the semiarid Southern Rangelands of Western Australia would reduce distance travelled on days with high mean daily temperature. Eight Merino ewes were fitted with GPS collars for 3 weeks in a 5575-ha paddock on Carlaminda station (28°20′S, 116°41′E). Mean daily temperature was used to separate the 18 days of the study into three temperature classes, cool (≤23.2°C), warm (23.3 to 25.9°C) and hot (≥26.0°C). Sheep travelled more quickly (P < 0.05) and further from water on cool days, compared with warm and hot days (3.74 v. 2.93 and 2.73 km from water, respectively; P < 0.001). On cool days, sheep spent most of their time grazing in the western area of the paddock. This area was rarely visited on warm or hot days. Mapping livestock distribution may assist in strategic relocation of existing water points and/or justify the development of additional watering points. However, our results suggest that sheep adjust their behaviour during hot weather, which may be a strategy to conserve energy, manage higher water requirements and/or reduce thermal load. Although grazing range decreases with higher temperatures, overall utilisation of a paddock may not be severely affected unless cooler days were too infrequent to facilitate regular access to these areas.
Increased levels of cysteinyl leukotrienes and prostaglandin E2 in gastrointestinal tract mucus are associated with decreased faecal dry matter in Merino rams during nematode infection
Authors: Williams A. R. , Karlsson L. J. E. , Palmer D. G. , Williams I. H. , Vercoe P. E. , Greeff J. C. , Emery D. L.
Published: June 2008

Immune-mediated scouring in sheep is a mucosal hypersensitivity response incited by infective larvae of gastrointestinal nematodes in the southern half of Australia and in New Zealand, regions characterised by a Mediterranean, winter-rainfall climate. To gain insights into the underlying mechanism(s), this study investigated the relationship between nematode infection of sheep in pens, faecal dry matter and release of inflammatory mediators in the intestinal tract. Six worm-free, immune rams received a dose of 3000 Trichostrongylus third stage larvae (L3) and 3000 Ostertagia L3 per week for 6 weeks, after which they were euthanased. Three rams acted as uninfected controls. Faecal dry matter was significantly lower in the infected group from the first week of infection until the end of the trial. Concentrations of cysteinyl leukotrienes and prostaglandin E2 were higher in mucus from both the abomasum and the small intestine of infected rams compared with controls. Within the infected group, concentrations of both mediators were higher in mucus from the small intestine than from the abomasum. There were greater numbers of eosinophilic granulocytes and mucosal mast cells in abomasal and small-intestinal tissue sections from infected rams compared with the controls. The results are consistent with the hypothesis that nematode infection causes an inflammatory response in the gastrointestinal mucosa, characterised by increased fluid secretion.
The challenges of diagnosis and treatment of malaria in pregnancy in low resource settings
Authors: OMO‐AGHOJA LAWRENCE O. , ABE EGHE , FEYI‐WABOSO PAUL , OKONOFUA FRIDAY E.
Published: June 2008

Malarial infestation in pregnancy is a major public health concern in endemic countries and ranks high amongst the commonest complications of pregnancy, especially in large areas of Africa and Asia. It is an important preventable cause of significant maternal morbidity and mortality with associated fetal as well as perinatal wastage. The burden of malaria is greatest in sub‐Saharan Africa where it contributes directly or indirectly to maternal and perinatal morbidity and mortality. The need for prompt and accurate diagnosis as well as prevention and treatment of malaria during pregnancy cannot, therefore, be overemphasized. This commentary focuses on the challenges of diagnosis and treatment of malaria in pregnancy.
Pregnant women's awareness and knowledge of mother‐to‐child transmission of HIV in South Central China
Authors: LUO YANG , HE GUO‐PING
Published: June 2008

Objective. China has, in recent years, seen an increase in the number of HIV‐positive children due to the increase in number of HIV‐positive women. The purpose of this study was to investigate the awareness and knowledge of mother‐to‐child transmission of HIV and its prevention among pregnant women attending the antenatal clinics in South Central China. Methods. The study was carried out in three antenatal clinics of three hospitals from February 2005 to March 2006, and it was based on personal interviews and questionnaires designed to assess the pregnant women's awareness about HIV/AIDS, evaluate their knowledge of possible routes of transmission, particularly mother‐to‐child transmission, and determine their familiarity with measures that prevent vertical transmission from mother to child. Two thousand three hundred and ninety pregnant women were included in the study. Results. All individuals were aware of HIV/AIDS. The majority (91%) of those women were aware that HIV/AIDS can coexist with pregnancy but only 64% had heard about mother‐to‐child transmission. Transplacental route, vaginal delivery and breastfeeding were identified as routes of transmission from mother to child by 85%, 60% and 20% of respondents, respectively. Cesarean section was believed to be a route of transmission by 55% of respondents, but no one identified cesarean section as a method of prevention of mother‐to‐child transmission. Conclusions. The level of awareness and knowledge of HIV/AIDS among pregnant women attending our antenatal clinics seems to be superficial; more education and knowledge about mother‐to‐child transmission are needed in China.
Reaching the students that student‐centred learning cannot reach
Authors: Hockings Christine
Published: June 2008

Student‐centred learning has the potential to engage a more academically diverse student body than the more conventional teacher‐centred approaches. In spite of the evidence in favour of student‐centred learning, a recent study showed that it was ineffective for around 30% of undergraduates in a large and diverse group studying business operations management. The possible reasons for this are explored in two ways. First, the literature relating to student engagement and participation is reviewed from three different perspectives: the sociological, the epistemological and the approaches to learning perspectives. Second, all three perspectives are applied to data generated from the original study within the context of a post‐1992 university. The advantages of a three‐perspective approach over a single‐perspective approach are discussed. Finally, the development of a holistic model integrating all three perspectives is called for, to be used as a guide for further empirical research into student engagement and as a tool for evaluating and developing inclusive and engaging learning environments.
Effects of different compression techniques on diagnostic accuracies of breast masses on digitized mammograms
Authors: Liang Zhigang , Du Xiangying , Liu Jiabin , Yang Yanhui , Rong Dongdong , Yao Xinyu , Li Kuncheng
Published: June 2008

Background: The JPEG 2000 compression technique has recently been introduced into the medical imaging field. It is critical to understand the effects of this technique on the detection of breast masses on digitized images by human observers.

Purpose: To evaluate whether lossless and lossy techniques affect the diagnostic results of malignant and benign breast masses on digitized mammograms.

Material and Methods: A total of 90 screen-film mammograms including craniocaudal and lateral views obtained from 45 patients were selected by two non-observing radiologists. Of these, 22 cases were benign lesions and 23 cases were malignant. The mammographic films were digitized by a laser film digitizer, and compressed to three levels (lossless and lossy 20:1 and 40:1) using the JPEG 2000 wavelet-based image compression algorithm. Four radiologists with 10–12 years’ experience in mammography interpreted the original and compressed images. The time interval was 3 weeks for each reading session. A five-point malignancy scale was used, with a score of 1 corresponding to definitely not a malignant mass, a score of 2 referring to not a malignant mass, a score of 3 meaning possibly a malignant mass, a score of 4 being probably a malignant mass, and a score of 5 interpreted as definitely a malignant mass. The radiologists’ performance was evaluated using receiver operating characteristic analysis.

Results: The average Az values for all radiologists decreased from 0.8933 for the original uncompressed images to 0.8299 for the images compressed at 40:1. This difference was not statistically significant. The detection accuracy of the original images was better than that of the compressed images, and the Az values decreased with increasing compression ratio.

Conclusion: Digitized mammograms compressed at 40:1 could be used to substitute original images in the diagnosis of breast cancer.
Book Review
Authors: Thorelius Lars
Published: June 2008

Ultrasonography in Urology: A Practical Approach to Clinical Problems. 2nd edition. Edited by E. I. Bluth, C. B. Benson, P. W. Ralls, & M. J. Siegel. New York: Thieme Medical Publications, 2008. ISBN: 978-1-58890-609-0 /978-3-13-129132-5. 180 pages. Price (paperback): USD 79.95
Bewitchment, Biology, or Both: The Co‐Existence of Natural and Supernatural Explanatory Frameworks Across Development
Authors: Legare Cristine H. , Gelman Susan A.
Published: June 2008

Three studies examined the co‐existence of natural and supernatural explanations for illness and disease transmission, from a developmental perspective. The participants (5‐, 7‐, 11‐, and 15‐year‐olds and adults; N = 366) were drawn from 2 Sesotho‐speaking South African communities, where Western biomedical and traditional healing frameworks were both available. Results indicated that, although biological explanations for illness were endorsed at high levels, witchcraft was also often endorsed. More important, bewitchment explanations were neither the result of ignorance nor replaced by biological explanations. Instead, both natural and supernatural explanations were used to explain the same phenomena, and bewitchment explanations were highest among adults. Taken together, these data provide insight into how diverse, culturally constructed belief systems about illness co‐exist across development.
Working Memory in Wayfinding—A Dual Task Experiment in a Virtual City
Authors: Meilinger Tobias , Knauff Markus , Bülthoff Heinrich H.
Published: June 2008

This study examines the working memory systems involved in human wayfinding. In the learning phase, 24 participants learned two routes in a novel photorealistic virtual environment displayed on a 220° screen while they were disrupted by a visual, a spatial, a verbal, or—in a control group—no secondary task. In the following wayfinding phase, the participants had to find and to “virtually walk” the two routes again. During this wayfinding phase, a number of dependent measures were recorded. This research shows that encoding wayfinding knowledge interfered with the verbal and with the spatial secondary task. These interferences were even stronger than the interference of wayfinding knowledge with the visual secondary task. These findings are consistent with a dual‐coding approach of wayfinding knowledge.
Lake Huron climatology, inter-lake exchange and mean circulation
Authors: Schertzer W. M. , Assel R. A. , Beletsky D. , Croley T. E. , Lofgren B. M. , Saylor J. H. , Schwab D. J.
Published: June 2008

Selected key features of the physical limnology, hydrology and climate influencing Lake Huron is presented. The lake is deep (229 m), consists of four interconnected bodies of water and currently there are no diversions into or out of the lake. Long-term annual summaries of meteorological and hydrological variables show that the lake affects spatial distributions across the basin. An estimate of the long-term hydrologic budget shows the relative importance of the major inflows, outflows and net basin supply. Long-term monthly average water level is 176.6 m. Monthly mean total heat flux ranges from −155 W m− 2 in December to 154 W m− 2 in June. Light attenuation is higher in Saginaw Bay and the nearshore compared to the mid-lake. Ice extent can be an important factor in the Lake Huron system with values ranging from < 10% to > 90% depending on winter severity. Surface and mean lake temperature for shallow North Channel are similar, however, large volumes of main Lake Huron and Georgian Bay results in mean temperatures nearly 10°C less than surface temperatures in summer. Inter-lake exchange at the Straits of Mackinac is about 2 cm s− 1 but fluctuating flows can be up to 30 times larger. The averaged summer and winter circulation shows cyclonic patterns for Lake Huron.
Control of translation initiation: a model-based analysis from limited experimental data
Authors: Dimelow Richard J , Wilkinson Stephen J
Published: June 2008

We have built a detailed kinetic model of translation initiation in yeast and have used a novel approach to determine the flux controlling steps based on limited experimental data. An efficient parameter estimation method was adapted in order to fit the most uncertain parameters (rate constants) to
in vivo
measurements in yeast. However, it was found that there were many other sets of plausible parameter values that also gave a good fit of the model to the data. We therefore used random sampling of this uncertain parameter space to generate a large number of diverse fitted parameter sets. A compact characterization of these parameter sets was provided by considering flux control. In particular, we suggest that the rate of translation initiation is most strongly influenced by one of two reactions: either the guanine nucleotide exchange reaction involving initiation factors eIF2 and eIF2B or the assembly of the multifactor complex from its constituent protein/tRNA containing complexes. It is hoped that the approach presented in this paper will add to our understanding of translation initiation pathway and can be used to identify key system-level properties of other biochemical processes.
A contribution to meteorology by Spencer Cowper, Dean of Durham 1746–74
Authors: Kenworthy Joan M , McCollum Margaret S
Published: June 2008

The writer of a hitherto unnoticed letter dated 17 January 1770, which was received by the National Meteorological Library and Archive, which was received in 1935 by the National Meteorological Library from the Radcliffe Observatory, Oxford, has been identified as Spencer Cowper, Dean of Durham from 1746 to 1774. In the letter Cowper summarizes the weather observations he made in Durham in 1769, provides a short but masterly analysis of the regional climate and refers to the completion of a naturalist's journal, which he planned to send to Oxford. This paper makes the case that the recipient of the letter was almost certainly Thomas Hornsby, first Radcliffe Observer, whose links with Durham are fully explored. Investigation of the context in which the letter was written reveals the hitherto neglected range and depth of Spencer Cowper's scientific interests and connections. The journal to which Cowper refers has not yet been traced despite extensive searches, but, through an examination of the development and use of naturalists' journals during the late 1760s and of the wider national and regional context of data collection and observation evident in correspondence between those involved, new light is shed on Spencer Cowper's likely awareness and associations, some of which are evident in the newly analysed catalogue of his books and scientific instruments that were offered for sale after his death.
Assessment of AFLP® marker behaviour in enriching STS radiation hybrid maps
Authors: Ajmone Marsan P. , Gorni C. , Milanesi E. , Mazza R. , Van Eijk M. J. T. , Peleman J. D. , Williams J. L.
Published: June 2008

Radiation hybrid (RH) mapping provides a powerful tool to build high‐resolution maps of genomes. Here, we demonstrate the use of the AFLP® technique for high‐throughput typing of RH cell lines. Cattle were used as the model species because an RH panel was available to investigate the behaviour of AFLP markers within the microsatellite‐ and STS‐based maps of this species. A total of 747 AFLP markers were typed on the TM112 RH radiation panel and 651 of these were assigned by two‐point analysis to the 29 bovine autosomes and sex chromosomes. AFLP markers were added to the 1222 microsatellite and STS markers that were included in earlier RH maps. Multipoint maps were constructed for seven example chromosomes, which retained 248 microsatellite and STS markers, and added 123 AFLP markers at LOD 4. The addition of the AFLP markers increased the number of markers by 42.1% and the map length by 10.4%. The AFLP markers showed lower retention frequency (RF) values than the STS markers. The comparison of RF values in AFLP markers and their corresponding AFLP‐derived STSs demonstrated that the lower RF values were due to the lower detection sensitivity of the AFLP technique. Despite these differences, AFLP and AFLP‐derived STS markers mapped to identical or similar positions. These results demonstrate that it is possible to merge AFLP and microsatellite markers in the same map. The application of AFLP technology could permit the rapid construction of RH maps in species for which extensive genome information and large numbers of SNP and microsatellite markers are not available.
Refractory immune thrombocytopenic purpura: current strategies for investigation and management
Authors: Psaila Bethan , Bussel James B.
Published: June 2008

There is currently no consensus on how best to manage refractory immune thrombocytopenic purpura (ITP). In part, this reflects the need for individualized treatment due to the wide spectrum of patients' requirements and responsiveness to therapies. The objective of this review is to provide a clinically useful guide to current management strategies. This article suggests investigations to identify factors that may exacerbate thrombocytopenia and underlie poor therapeutic responses, and highlights emerging therapies, including the thrombopoietic agents, which are anticipated to dramatically alter the natural history of “refractory” ITP. Morbidity, mortality and heath‐related quality of life are also discussed.
Clinicopathologic challenge
Authors: Kung Elaine F. , Soltani Keyoumars , Petronic‐Rosic Vesna
Published: June 2008

What is your diagnosis?
Overexpression of a rice defense‐related F‐box protein gene OsDRF1 in tobacco improves disease resistance through potentiation of defense gene expression†
Authors: Cao Yifei , Yang Yayun , Zhang Huijuan , Li Dayong , Zheng Zhong , Song Fengming
Published: June 2008

F‐box proteins play important roles in plant growth/development and responses to environmental stimuli through targeting substrates into degradation machinery. A rice defense‐related F‐box protein gene, OsDRF1, was cloned and identified during a course of study aimed at elucidating the molecular basis of induced immunity in rice. OsDRF1 encodes a protein of 328 amino acids, containing a highly conserved F‐box domain. Expression of OsDRF1 was induced upon treatment with benzothiadiazole (BTH), a chemical inducer of defense responses in rice. Moreover, in BTH‐treated rice seedlings, expression of OsDRF1 was further induced by infection with Magnaporthe grisea, the rice blast fungus, compared with those in water‐treated seedlings. OsDRF1 was also upregulated in rice seedlings after treatment with ABA. Overexpression of OsDRF1 in transgenic tobacco resulted in enhanced disease resistance against tomato mosaic virus (ToMV) and Pseudomonas syringae pv. tabaci and strengthened expression of defense‐related genes after salicylic acid treatment or ToMV infection. Root elongation of the OsDRF1‐overexpressing transgenic seedlings was significantly inhibited by ABA, indicating that overexpression of OsDRF1 resulted in increased ABA sensitivity. The results suggest that OsDRF1 plays a role in disease resistance via upregulating defense‐related gene expression and that OsDRF1 may also be involved in the response to ABA.
Coaching parents to enable children's participation: An approach for working with parents and their children
Authors: Graham Fiona , Rodger Sylvia , Ziviani Jenny
Published: June 2008

In this paper, Occupational Performance Coaching (OPC) is presented as a means whereby occupational therapists can support parents in achieving goals for themselves and their children. OPC is a coaching intervention that assists parents to recognise and implement social and physical environment changes that support more successful occupational performance for themselves and their children. OPC utilises collaborative problem‐solving within a coaching relationship in which parents are guided towards identifying and implementing effective, autonomous solutions to occupational performance dilemmas.

OPC is described in relation to the principles of contemporary practice; in particular that intervention is both family‐ and occupation‐centred, and leads, as directly as possible, to the enablement of children's participation at home and in the community. Tentative empirical support for coaching parents draws on the supporting evidence for similar interventions in cognate disciplines. The unique features of OPC, namely, overt collaborative analysis of performance with parents and parent‐initiated solution finding, are highlighted and their potential contributions to interventions currently employed by therapists are outlined. Recommendations are advanced as to how further research can support the adoption of this intervention strategy.