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Search Results: 1 - 10 of 89994 matches for " Stephanie I. Wakeling "
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Mitotic Arrest in Teratoma Susceptible Fetal Male Germ Cells
Patrick S. Western, Rachael A. Ralli, Stephanie I. Wakeling, Camden Lo, Jocelyn A. van den Bergen, Denise C. Miles, Andrew H. Sinclair
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0020736
Abstract: Formation of germ cell derived teratomas occurs in mice of the 129/SvJ strain, but not in C57Bl/6 inbred or CD1 outbred mice. Despite this, there have been few comparative studies aimed at determining the similarities and differences between teratoma susceptible and non-susceptible mouse strains. This study examines the entry of fetal germ cells into the male pathway and mitotic arrest in 129T2/SvJ mice. We find that although the entry of fetal germ cells into mitotic arrest is similar between 129T2/SvJ, C57Bl/6 and CD1 mice, there were significant differences in the size and germ cell content of the testis cords in these strains. In 129T2/SvJ mice germ cell mitotic arrest involves upregulation of p27KIP1, p15INK4B, activation of RB, the expression of male germ cell differentiation markers NANOS2, DNMT3L and MILI and repression of the pluripotency network. The germ-line markers DPPA2 and DPPA4 show reciprocal repression and upregulation, respectively, while FGFR3 is substantially enriched in the nucleus of differentiating male germ cells. Further understanding of fetal male germ cell differentiation promises to provide insight into disorders of the testis and germ cell lineage, such as testis tumour formation and infertility.
Signaling through the TGF Beta-Activin Receptors ALK4/5/7 Regulates Testis Formation and Male Germ Cell Development
Denise C. Miles, Stephanie I. Wakeling, Jessica M. Stringer, Jocelyn A. van den Bergen, Dagmar Wilhelm, Andrew H. Sinclair, Patrick S. Western
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054606
Abstract: The developing testis provides an environment that nurtures germ cell development, ultimately ensuring spermatogenesis and fertility. Impacts on this environment are considered to underlie aberrant germ cell development and formation of germ cell tumour precursors. The signaling events involved in testis formation and male fetal germ cell development remain largely unknown. Analysis of knockout mice lacking single Tgfβ family members has indicated that Tgfβ's are not required for sex determination. However, due to functional redundancy, it is possible that additional functions for these ligands in gonad development remain to be discovered. Using FACS purified gonadal cells, in this study we show that the genes encoding Activin's, TGFβ's, Nodal and their respective receptors, are expressed in sex and cell type specific patterns suggesting particular roles in testis and germ cell development. Inhibition of signaling through the receptors ALK4, ALK5 and ALK7, and ALK5 alone, demonstrated that TGFβ signaling is required for testis cord formation during the critical testis-determining period. We also show that signaling through the Activin/NODAL receptors, ALK4 and ALK7 is required for promoting differentiation of male germ cells and their entry into mitotic arrest. Finally, our data demonstrate that Nodal is specifically expressed in male germ cells and expression of the key pluripotency gene, Nanog was significantly reduced when signaling through ALK4/5/7 was blocked. Our strategy of inhibiting multiple Activin/NODAL/TGFβ receptors reduces the functional redundancy between these signaling pathways, thereby revealing new and essential roles for TGFβ and Activin signaling during testis formation and male germ cell development.
“Girls are dancin’”: shōjo culture and feminism in contemporary Japanese art
Emily Wakeling
New Voices : A Journal for Emerging Scholars of Japanese Studies in Australia and New Zealand , 2011,
Abstract: This article explores the gender-transgressive expressions found in shōjo culture in order to highlight the potential for feminist analysis in the prevalence of the shōjo motif in contemporary Japanese art. Shōjo culture is a fascinating cultural space, within contemporary Japanese culture, which fosters creative expressions of gender that negate or make complex hegemonic categories. Departing from stereotypes of Japanese girls, this article will pay particular interest to an emerging wave of figurative contemporary art practices in which the figure of the shōjo is utilised for a new generation of feminist critique. Aoshima Chiho, Kunikata Mahomi, Takano Aya, Sawada Tomoko and Yanagi Miwa are among the current artists who feature the shōjo motif in contexts that foreground female subjectivities found paralleled in shōjo culture. These works will then be contextualised in the greater picture of current trends and themes in global contemporary feminist art.
Order-disorder transition in the Chialvo-Bak `minibrain' controlled by network geometry
Joseph Wakeling
Physics , 2002, DOI: 10.1016/S0378-4371(03)00147-X
Abstract: We examine a simple biologically-motivated neural network, the three-layer version of the Chialvo-Bak `minibrain' [Neurosci. 90 (1999) 1137], and present numerical results which indicate that a non-equilibrium phase transition between ordered and disordered phases occurs subject to the tuning of a control parameter. Scale-free behaviour is observed at the critical point. Notably, the transition here is due solely to network geometry and not any noise factor. The phase of the network is thus a design parameter which can be tuned. The phases are determined by differing levels of interference between active paths in the network and the consequent accidental destruction of good paths.
Uromedic? Pumpkin Seed Derived Δ7-Sterols, Extract and Oil Inhibit 5α-Reductases and Bind to Androgen Receptor in Vitro  [PDF]
Stefan Heim, Stephanie Seibt, Heike Stier, Margret I Moré
Pharmacology & Pharmacy (PP) , 2018, DOI: 10.4236/pp.2018.96015
Abstract: Dihydrotestosterone (DHT) is implicated in the development of benign prostate hyperplasia (BPH). We investigated if Uromedic? pumpkin (variety of Cucurbita pepo L. convar. citrullinina GREB. var. styriaca GREB) seed soft extract (active ingredients of GRANUFINK? Prosta forte 500 mg), seed oil and isolated Δ7-sterols could inhibit the conversion of [1,2,6,7-3H(N)]-testosterone to DHT by 5α-reductases. Also, we tested competition with [3H]-DHT for binding to the androgen receptor (AR). Pumpkin seed oil and pumpkin seed soft extract were identified as moderately active inhibitors of 5α-R1 and 5α-R2, with almost similar inhibitory capacities (IC50 < 5 mg/ml for 5α-R1 and about IC50 = 6 mg/ml for 5α-R2). The isolated Δ7-sterols were more active inhibitors (IC50 = 0.3 mg/ml for 5α-R1, IC50
Adaptivity and `Per learning'
Joseph Rushton Wakeling
Physics , 2004, DOI: 10.1016/j.physa.2004.05.028
Abstract: One of the key points addressed by Per Bak in his models of brain function was that biological neural systems must be able not just to learn, but also to adapt--to quickly change their behaviour in response to a changing environment. I discuss this in the context of various simple learning rules and adaptive problems, centred around the Chialvo-Bak `minibrain' model [Neurosci. 90 (1999) 1137--1148].
Intelligent systems in the context of surrounding environment
Joseph Wakeling,Per Bak
Physics , 2002, DOI: 10.1103/PhysRevE.64.051920
Abstract: We investigate the behavioral patterns of a population of agents, each controlled by a simple biologically motivated neural network model, when they are set in competition against each other in the Minority Model of Challet and Zhang. We explore the effects of changing agent characteristics, demonstrating that crowding behavior takes place among agents of similar memory, and show how this allows unique `rogue' agents with higher memory values to take advantage of a majority population. We also show that agents' analytic capability is largely determined by the size of the intermediary layer of neurons. In the context of these results, we discuss the general nature of natural and artificial intelligence systems, and suggest intelligence only exists in the context of the surrounding environment (embodiment). Source code for the programs used can be found at http://neuro.webdrake.net .
A Global Assessment of Long-Term Greening and Browning Trends in Pasture Lands Using the GIMMS LAI3g Dataset
Benjamin I. Cook,Stephanie Pau
Remote Sensing , 2013, DOI: 10.3390/rs5052492
Abstract: Pasture ecosystems may be particularly vulnerable to land degradation due to the high risk of human disturbance (e.g., overgrazing, burning, etc.), especially when compared with natural ecosystems (non-pasture, non-cultivated) where direct human impacts are minimal. Using maximum annual leaf area index (LAImax) as a proxy for standing biomass and peak annual aboveground productivity, we analyze greening and browning trends in pasture areas from 1982–2008. Inter-annual variability in pasture productivity is strongly controlled by precipitation (positive correlation) and, to a lesser extent, temperature (negative correlation). Linear temporal trends are significant in 23% of pasture cells, with the vast majority of these areas showing positive LAImax trends. Spatially extensive productivity declines are only found in a few regions, most notably central Asia, southwest North America, and southeast Australia. Statistically removing the influence of precipitation reduces LAImax trends by only 13%, suggesting that precipitation trends are only a minor contributor to long-term greening and browning of pasture lands. No significant global relationship was found between LAImax and pasture intensity, although the magnitude of trends did vary between cells classified as natural versus pasture. In the tropics and Southern Hemisphere, the median rate of greening in pasture cells is significantly higher than for cells dominated by natural vegetation. In the Northern Hemisphere extra-tropics, conversely, greening of natural areas is 2–4 times the magnitude of greening in pasture areas. This analysis presents one of the first global assessments of greening and browning trends in global pasture lands, including a comparison with vegetation trends in regions dominated by natural ecosystems. Our results suggest that degradation of pasture lands is not a globally widespread phenomenon and, consistent with much of the terrestrial biosphere, there have been widespread increases in pasture productivity over the last 30 years.
The effect of discrete vs. continuous-valued ratings on reputation and ranking systems
Matus Medo,Joseph Rushton Wakeling
Computer Science , 2010, DOI: 10.1209/0295-5075/91/48004
Abstract: When users rate objects, a sophisticated algorithm that takes into account ability or reputation may produce a fairer or more accurate aggregation of ratings than the straightforward arithmetic average. Recently a number of authors have proposed different co-determination algorithms where estimates of user and object reputation are refined iteratively together, permitting accurate measures of both to be derived directly from the rating data. However, simulations demonstrating these methods' efficacy assumed a continuum of rating values, consistent with typical physical modelling practice, whereas in most actual rating systems only a limited range of discrete values (such as a 5-star system) is employed. We perform a comparative test of several co-determination algorithms with different scales of discrete ratings and show that this seemingly minor modification in fact has a significant impact on algorithms' performance. Paradoxically, where rating resolution is low, increased noise in users' ratings may even improve the overall performance of the system.
The twisted path from farm subsidies to health care expenditures  [PDF]
Stephanie Bernell
Health (Health) , 2012, DOI: 10.4236/health.2012.412A216
Abstract:

Overweight and obese individuals are at increased risk for many diseases and health conditions, including but not limited to the following: hypertension; osteoarthritis; dyslipidemia; type 2 diabetes; coronary heart disease and stroke. Consequently, individuals who are obese are more likely to use health services and are more likely to use costly health services than non-obese individuals. Between 1987 and 2001, growth in obesity related health expenditures accounted for 27 percent of the growth in inflation-adjusted per capita health care spending. Researchers, popular press and the television news media have paid considerable attention to the effect that farm subsidies have on dietary habits and obesity. Prominent researchers in the field have concluded that US farm subsidies have had a negligible impact on obesity. However, even small increases in obesity rates are associated with higher health care expenditures. The primary intent of this study is to break down the linkages from farm subsidy to health expenditure and shed light on the unintended implications of the farm subsidy program. We find that agricultural subsidies have the potential to influence health care expenditures.

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