Dynamics of Multidimensional Secession

We explore a generalized Seceder Model with variable size selection groups and higher dimensional genotypes, uncovering its well-defined mean-field limiting behavior. Mapping to a discrete, deterministic version, we pin down the upper critical size of the multiplet selection group, characterize all relevant dynamically stable fixed points, and provide a complete analytical description of its self-similar hierarchy of multiple branch solutions.Comment: 4 pages, 4 figures, PR

DNA Display II. Genetic Manipulation of Combinatorial Chemistry Libraries for Small-Molecule Evolution

Biological in vitro selection techniques, such as RNA aptamer methods and mRNA display, have proven to be powerful approaches for engineering molecules with novel functions. These techniques are based on iterative amplification of biopolymer libraries, interposed by selection for a desired functional property. Rare, promising compounds are enriched over multiple generations of a constantly replicating molecular population, and subsequently identified. The restriction of such methods to DNA, RNA, and polypeptides precludes their use for small-molecule discovery. To overcome this limitation, we have directed the synthesis of combinatorial chemistry libraries with DNA “genes,” making possible iterative amplification of a nonbiological molecular species. By differential hybridization during the course of a traditional split-and-pool combinatorial synthesis, the DNA sequence of each gene is read out and translated into a unique small-molecule structure. This “chemical translation” provides practical access to synthetic compound populations 1 million-fold more complex than state-of-the-art combinatorial libraries. We carried out an in vitro selection experiment (iterated chemical translation, selection, and amplification) on a library of 10(6) nonnatural peptides. The library converged over three generations to a high-affinity protein ligand. The ability to genetically encode diverse classes of synthetic transformations enables the in vitro selection and potential evolution of an essentially limitless collection of compound families, opening new avenues to drug discovery, catalyst design, and the development of a materials science “biology.

Comment on ``Nonuniversal Exponents in Interface Growth''

Recently, Newman and Swift[T. J. Newman and M. R. Swift, Phys. Rev. Lett. {\bf 79}, 2261 (1997)] made an interesting suggestion that the strong-coupling exponents of the Kardar-Parisi-Zhang (KPZ) equation may not be universal, but rather depend on the precise form of the noise distribution. We show here that the decrease of surface roughness exponents they observed can be attributed to a percolative effect

Investigating Women's Experiences of Asthma Care in Pregnancy: A Qualitative Study.

Background : Most asthmatic women have normal pregnancies and complications are infrequent when their asthma is well-controlled. Symptom control and medical treatment are concerning to pregnant asthma suffers, as is the impact that their illness and treatment might have on their unborn baby. The aim was to investigate in a qualitative study the thoughts and feelings of women's experiences of asthma in pregnancy. Twenty-two women with asthma who had a pregnancy within two years were asked to participate. Seven women were interviewed when data saturation was achieved. Interviews were transcribed and analysed using the 'Framework' Method, independently analysed by two researchers and consensus reached concerning the construction of themes. The key themes that emerged were Asthma and pregnancy; Pregnancy and post-natal experiences; and Health professionals. These findings are globally interesting because of the prevalence of maternal asthma and they illustrate participants' experiences concerning their asthma care and their views on its improvement. Pregnant asthmatic women have concerns about their care and treatment which might be alleviated by outreach, joint working between respiratory doctors and nurse specialists, midwives and General Practice nurses. Targeted educational activities could form a part of this care delivery

Strategies to limit the impact of nematode pressure on sugarcane productivity in the Isis

Two trials were done in this project. One was a continuation of work started under a previous GRDC/SRDC-funded activity, 'Strategies to improve the integration of legumes into cane based farming systems'. This trial aimed to assess the impact of trash and tillage management options and nematicide application on nematodes and crop performance. Methods and results are contained in the following publication: Halpin NV, Stirling GR, Rehbein WE, Quinn B, Jakins A, Ginns SP. The impact of trash and tillage management options and nematicide application on crop performance and plant-parasitic nematode populations in a sugarcane/peanut farming system. Proc. Aust. Soc. Sugar Cane Technol. 37, 192-203. Nematicide application in the plant crop significantly reduced total numbers of plant parasitic nematodes (PPN) but there was no impact on yield. Application of nematicide to the ratoon crop significantly reduced sugar yield. The study confirmed other work demonstrating that implementation of strategies like reduced tillage reduced populations of total PPN, suggesting that the soil was more suppressive to PPN in those treatments. The second trial, a variety trial, demonstrated the limited value of nematicide application in sugarcane farming systems. This study has highlighted that growers shouldn’t view nematicides as a ‘cure all’ for paddocks that have historically had high PPN numbers. Nematicides have high mammalian toxicity, have the potential to contaminate ground water (Kookana et al. 1995) and are costly. The cost of nematicide used in R1 was approx. $320 -$350/ha, adding $3.50/t of cane in a 100 t/ha crop. Also, our study demonstrated that a single nematicide treatment at the application rate registered for sugarcane is not very effective in reducing populations of nematode pests. There appears to be some levels of resistance to nematodes within the current suite of varieties available to the southern canelands. For example the soil in plots that were growing Q183 had 560% more root knot nematodes / 200mL soil compared to plots that grew Q245. The authors see great value in investment into a nematode screening program that could rate varieties into groups of susceptibility to both major sugarcane nematode pests. Such a rating could then be built into a decision support ‘tree’ or tool to better enable producers to select varieties on a paddock by paddock basis

Effect of Grazing Muzzles on the Rate of Pelleted Feed Intake in Horses

Esophageal obstruction or “choke” is a relatively common occurrence in the equine industry. It often results from improper mastication, consuming feed too quickly, dehydration or a decrease in saliva production. Esophageal obstruction is a medical emergency during which a horse cannot dislodge a bolus of feed from the esophagus and must wait for human intervention or for the block to be softened and moved by peristalsis. This condition may result in the formation of ulcers, esophageal rupture, aspiration pneumonia, and possibly death. Grazing muzzles have been shown to slow the rate of forage intake. We hypothesized that grazing muzzles could also be used to decrease the rate of pelleted feed intake and so possibly reduce the risk of equine esophageal obstruction in horses fed large meals of pelleted feed. The objective of this research was to compare the rate of pelleted feed intake for horses wearing grazing muzzles to those wearing no muzzle. Utilizing a crossover design, horses were randomly assigned to three groups with each horse receiving each treatment. Treatments were as follows: No Muzzle (NM), Easy Breath Grazing Muzzle (EBGM), or Tough 1 Nylon Grazing Muzzle (TNGM). Eight adult stock-type horses age 5 ±1 years, were offered 2.27 kg of pelleted concentrate to consume in a 10-minute period once daily. The study was comprised of three periods (5 days each) with a two-day resting period between each. Horses were weighed daily and no significant change in bodyweight was observed. Data for daily intake were analyzed using the PROC MIXED procedure of SAS with significance established at P \u3c 0.05. Both the EBGM and the TNGM reduced rate of intake (P \u3c 0.05) during a 10-minute feeding interval as compared with NM. The findings of this study revealed that grazing muzzles may be a viable option to reduce the rate of intake of pelleted feed, which may benefit horses susceptible to choke as a 31 result of rapid feed ingestion

Long-Term Effects of Alternative Group Selection Harvesting Designs on Stand Production

Interest in group selection harvesting has increased in recent years because of limitations associated with both clearcutting and single-tree selection. Field data have suggested that group selection openings can have higher production rates than single-tree gaps, but whether this translates into higher production rates at the stand level is not clear. We used CANOPY, a crown-based northern hardwoods model calibrated with data from uneven-aged and even-aged stands, to simulate sustainable harvest volumes of a number of different group selection approaches over 300 years, and also compared results with those from single-tree selection and clearcutting. When a combination of single-tree and group selection was used with groups making up 3% of the stand area per cutting cycle, net harvestable production rates were similar to those of single-tree selection, and opening size (100-4000m2) had little effect on production rates. As the percentage of the matrix in groups increased from 1 to 9% per cutting cycle, production actually showed a small but consistent decline of about 6 to 7%. When group selection was used alone with no cutting between the groups, production rates varied considerably depending on opening size and rotation age. Small group selection (200 m2) had production rates similar to or slightly higher than single-tree selection, whereas 2000 m2 openings resulted in a production declines of 30 to 35%. Large patch sizes appear to have relatively low net production because of unsalvaged mortality. Similar trends were observed in unthinned even-aged stands compared to those thinned at 15-yr intervals. Although our results confirmed that trees in even-aged stands are more efficient producers than those in uneven-aged stands, there appear to be countervailing tendencies that reduce production rates in large single-cohort patches, including a lag time during the first few decades when production rates of merchantable volume in large openings are very low

Laying the Groundwork: Linking Internal Agenda-Setting Processes Of Interest Groups to Their Role in Policy Making

Although scholarship has highlighted the role of stakeholders in policy making, less is known about the preparations they make that lay the groundwork for their lobbying activities. This article links ideas on collaborative governance with the study of agenda setting within interest groups. We outline an orthodox mode of agenda setting that anticipates groups possess a proactive policy mode, an institutionalized policy platform, and a pyramid-like agenda structure. Subsequently, we use this orthodox mode as a heuristic device for examining agenda structures and processes, combining survey data on the practices of groups in Australia with illustrative qualitative evidence.The politics and administration of institutional chang

How do interest groups legitimate their policy advocacy? Reconsidering linkage and internal democracy in times of digital disruption

The ongoing embrace of interest groups as agents capable of addressing democratic deficits in governing institutions is in large part because they are assumed to contribute democratic legitimacy to policy processes. Nonetheless, they face the challenge of legitimating their policy advocacy in democratic terms, clarifying what makes them legitimate partners in governance. In this article we suggest that digital innovations have disrupted the established mechanisms of legitimation. While the impact of this disruption is most easily demonstrated in the rise of a small number of ‘digital natives’, we argue that the most substantive impact has been on more conventional groups, which typically follow legitimation logics of either representation or solidarity. While several legacy groups are experimenting with new legitimation approaches, the opportunities provided by technology seem to offer more organizational benefits to groups employing the logic of solidarity, and appear less compatible with the more traditional logic of representation.The politics and administration of institutional chang

Conceptualising the policy engagement of interest groups: Involvement, access and prominence

While much progress has been made in empirically mapping and analysing a variety of interest group activities in the last decade, less attention has been devoted to conceptual work that clearly defines and distinguishes different forms of policy engagement. This article contributes to this endeavour by developing a theoretical framework that explicitly links currently available measures of the policy engagement of groups to the distinct concepts of group involvement, access and prominence. It argues that greater conceptual clarity will lead to better accumulation of knowledge in the sub-field and a better understanding of the role of interest groups in political systems.The politics and administration of institutional chang