Oil Prices, Profits, and Recessions : An Inquiry Using Terrorism as an Instrumental Variable

Nearly all post-war recessions have been preceded by oil-price shocks, but is this because spikes in the price of petroleum cause economic downturns? Most research has ignored an identification problem : oil prices and the state of the world economy are endogenously determined. This paper uses terrorist incidents as an instrumental variable. In an international panel of industries, we show that after correction for simultaneity bias — though not before — the price of oil has large negative effects upon profitability. Our results seem to lend support to the claim that oil-price spikes can be a source of recessions.

Seeds as Artifacts of Communities of Practice: The Domestication of Erect Knotweed in Eastern North America

Humans are the ultimate ecosystem engineers, and in transforming ecosystems we also change the selective environment for the plants and animals that live among us. The bodies and behaviors of domesticated plants and animals are thus rich artifacts of traditional ecological knowledge and practice. I study the morphology and behavior of domesticated plants as a proxy for ancient agricultural communities of practice. The transition from food procurement to food production is one of the most significant shifts in human history. I consider this process as the evolution and spread of a knowledge system. Domestication studies are usually focused on differentiating wild from domestic types, but I wanted to investigate variation under cultivation. Normally discussed in the context of contemporary or historical small-scale farming, landraces are plant varieties that have been developed to grow particularly well under local conditions or to suit local preferences. Because landraces need to be maintained across generations of both plants and people, they are reflections of communities of practice, social learning, and Traditional Ecological Knowledge systems. By undertaking a detailed case study of variation within a single crop, I hoped to be able to use seeds in the same way that pottery, lithic tools, or iconography are used: to reveal shared traditions and connections between communities. This dissertation is focused on the lost crops of Eastern North America: a suite of annual seed crops that were cultivated for thousands of years before the introduction of maize and other tropical crops through trade. These crops are referred to as the Eastern Agricultural Complex (EAC). I chose to investigate one of these, erect knotweed (Polygonum erectum L.), which was cultivated for its edible seeds by Indigenous people in Eastern North American for ~2,000 years. My goals were 1) to establish whether or not erect knotweed had been domesticated by ancient farmers; and 2) to document variation under cultivation that might reveal different communities of practice in Eastern North America. This dissertation consists of five chapters: 1) A formal description of the domesticated sub-species of erect knotweed (Polygonum erectum ssp. watsoniae N.G. Muell.) including taxonomic background and a comparative analysis of other species of Polygonum native to the study area/ 2) An overview of domestication syndrome in a desiccated assemblage of erect knotweed from the Whitney Bluff site, Arkansas, and a discussion of its implications for ancient agricultural practice in Eastern North America. 3) The results of field studies and experimental cultivation of erect knotweed over two growing seasons, with a discussion of the hypothesized roles of plasticity and heredity in the domestication of this species. 4) An experimental study of the processes that affect preservation of erect knotweed seeds and fruits, namely: carbonization (burning in anoxic conditions) and taphonomy (physical weathering after deposition). These processes systematically bias the archaeobotanical record and need to be accounted for in domestication studies. 5) A review of the archaeological background, and a comparison of ancient erect knotweed assemblages from 14 archaeological sites spanning 2,000 years. My concluding thoughts place this research in the context of global studies of domestication and food production. I suggest that optimal foraging models used in human behavioral ecology may consistently under-rank the seeds of small seeded annuals, and that plasticity under cultivation may have been one factor that made disturbance adapted plants attractive to ancient foragers. I argue that niche construction, food production, and delayed return strategies are all roughly synonymous terms, and that domestication is a likely, but not predetermined, outcome of such systems and behaviors. The spread of food producing economies was dependent on the spread of complex systems of knowledge through interacting communities of practice and without these systems of traditional ecological knowledge domesticated varieties could not be maintained

Speaking up in resource-constrained settings: how to secure safe surgical care in the moment and in the future?

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Relevance of health literacy models for people with severe mental illness

People with severe mental illness experience elevated levels of impairment, morbidity and health-risk behaviours compared with the general population. Despite this, it is consistently reported that they do not visit health professionals, including preventative health professionals, as regularly as the general population. Their poor health suggests that current health promotion efforts have been largely ineffective in addressing their specific needs. Barriers that might explain this include lack of motivation, expense and lack of access. Health literacy is also a potentially important factor. As a part of a programme of work to develop appropriate and effective health promotion for this group, we have explored existing health-literacy models and their relevance to marginalized populations, in particular, people experiencing severe mental illness. A comprehensive search of the literature was undertaken. Models of health literacy identified were analyzed to determine the source population, underpinning theory/frameworks, supporting research evidence and to consider their potential generalisability. This paper presents an analysis of existing health-literacy models in the context of severe mental illness. We propose that because existing models of health literacy were developed through consultation with people experiencing challenges to specific health and social issues, for example, cancer, low income and limited education, this raises questions as to the applicability of these models to people experiencing severe and ongoing mental illness. Whilst such individuals were not actively excluded in the development of the existing models, we propose the development of an alternative model which considers this population\u27s needs and limitations in accessing effective health-promotion campaigns/programs.<br /

Multiple small monthly doses of dicyandiamide (DCD) did not reduce denitrification in Waikato dairy pasture

The effectiveness of multiple small doses of the nitrification inhibitor dicyandiamide (DCD) to decrease denitrification under warm moist conditions was tested in a 1-year field trial on a grazed dairy pasture. DCD was applied approximately every 4 weeks as an aqueous spray onto ten replicate plots 3 days after rotational grazing by dairy cows. Each application was at the rate of 3 kg DCD ha⁻¹, with a total annual application of 33 kg ha⁻¹. Denitrification was assessed 5 days after each DCD application using the acetylene block method. At the end of the trial, the rate of degradation of DCD under summer conditions was measured. DCD significantly decreased the mean annual nitrate concentration by about 17%. Denitrification and denitrification enzyme activity were highly variable and no significant effect of DCD in decreasing denitrification was detected. In the summer month of December, DCD degraded rapidly with an estimated half-life of 5 ± 3 days (mean and standard deviation)

Aluminium-induced gene expression in sugarcane roots.

Thesis (M.Sc.)-University of Natal, Durban, 2002.Due to the increasing prevalence and severity of Al phytoxicity in certain regions of the South African sugar industry, a research programme has been initiated at SASEX to elucidate the molecular mechanisms by which sugarcane detects and responds to the metal. As part of this larger investigation, the current study aimed to assess the response of a reportedly Al tolerant cultivar, Saccharum spp. hybrid cv. N12, to phytotoxic levels of Al. Hydroponically-grown plants of this commercial genotype were used in Al inhibition studies, the results of which indicated that exposure of plants to 250µM Al for 24 hours resulted in maximum reduction of root elongation. Under these conditions, root growth was inhibited by approximately 36%, compared with only 4% for the 50µM Al treatment. Subsequently, this exposure regime was used to gather the terminal 5 to 10mm of root tips, the site of the primary Al lesion, of challenged and control, unchallenged plants for molecular analysis. Total RNA was extracted from the Al challenged and control root tips, from which mRNA was subsequently isolated, reverse transcribed and converted to double-stranded cDNA. The two populations of cDNA were reciprocally subtracted from each other and used to construct subtractive cDNA libraries in Lambda ZAP®II phages. Randomly selected clones, 576 representatives from each of the libraries, were screened using membrane-based array technology. Results indicated that only 33% (190) of the Al-treatment specific library cDNAs were found to be more highly expressed under conditions of Al stress than under control conditions. Of these potentially Al response-related cDNAs, 25 were sequenced and submitted to sequence databases for the assignment of putative identities. No genic sequences known to be directly associated with the Al stress response were identified, however, several were found to be related to pathogenesis or general stress pathways. Although further Northern hybridisation work is required to validate these results, they suggest that the induction of general stress response pathways may be involved in the aluminium stress response of this sugarcane cultivar. Such Al stress-related sequences could have applications in marker-assisted breeding programmes and as candidate genes for the genetic engineering of tolerant genotypes

Microwave Based Weed Control and Soil Treatment

The Yearbook mirrors the annual activities of staff and visiting fellows of the Maimonides Centre and reports on symposia, workshops, and lectures taking place at the Centre. Although aimed at a wider audience, the yearbook also contains academic articles and book reviews on scepticism in Judaism and scepticism in general. Staff, visiting fellows, and other international scholars are invited to contribut

The steady-state repertoire of human SCF Ubiquitin ligase complexes does not require ongoing Nedd8 conjugation

The human genome encodes 69 different F-box proteins (FBPs), each of which can potentially assemble with Skp1-Cul1-RING to serve as the substrate specificity subunit of an SCF ubiquitin ligase complex. SCF activity is switched on by conjugation of the ubiquitin- like protein Nedd8 to Cul1. Cycles of Nedd8 conjugation and deconjugation acting in conjunction with the Cul1-sequestering factor Cand1 are thought to control dynamic cycles of SCF assembly and disassembly, which would enable a dynamic equilibrium between the Cul1- RING catalytic core of SCF and the cellular repertoire of FBPs. To test this hypothesis, we determined the cellular composition of SCF complexes and evaluated the impact of Nedd8 conjugation on this steady-state. At least 42 FBPs assembled with Cul1 in HEK 293 cells, and the levels of Cul1-bound FBPs varied by over two orders of magnitude. Unexpectedly, quantitative mass spectrometry revealed that blockade of Nedd8 conjugation led to a modest increase, rather than a decrease, in the overall level of most SCF complexes. We suggest that multiple mechanisms including FBP dissociation and turnover cooperate to maintain the cellular pool of SCF ubiquitin ligases