The Synthesis of Functionalised beta-Lactams

N-t-Butyldimethylsilyl imines were prepared readily by oxidation of the corresponding primary amines. The application of N-t-butyl-dimethylsilyl imines to the synthesis of monocyclic beta-lactams was examined via the ester-imine condensation reaction with silyl ketene acetals. Initial choice of Znl2 as Lewis acid for this reaction proved fruitful in certain instances. This reaction, performed in the presence of t-BuOH to suppress reaction of the initially formed N-metallo beta-amino ester with a further molecule of activated imine, followed by treatment with Grignard reagent, displays a modest trans selectivity in the product beta-lactams. However, difficulties were encountered during utilization of more highly functionalised N-t-butyldimethylsilyl imines. As a result, a second Lewis acid system was investigated. Utilization of trimethylsilyl trifluoromethanesulphonate (TMSOTf) as the Lewis acid component produced, in a one-pot process, a range of beta-lactams in a trans-selective manner. Chemical yields resulting from this approach were comparable to those achieved using Znl2 as Lewis acid and the diastereoselectivities found showed a modest increase over those induced in the earlier approach. Low temperature quenching of the derived from treatment of a non-enolisable aldehyde with lithium hexamethyldisilazide resulted in formation of the corresponding N,N,O-tris(trimethylsilyl) amine acetal. Treatment of these compounds with TMSOTf provides access to the same reactive iminium species as found in the reaction between N-silyl imines and TMSOTf and, as such, provides an alternative route to beta-lactam synthesis. Two functionalised silyl ketene acetals were prepared. Attempts to incorporate these substrates into the ester-imine condensation process met with only partial success. The cyclic silyl ketene acetal derived from delta-valerolactone was incorporated into a beta-lactam nucleus, although some atypical characteristics were observed in this system. As an alternative source of the electrophilic iminium species generated in the reaction between an imine or amine acetal with a Lewis acid, the reactivity of enamines was examined. Lewis acid catalysis did allow access to beta-amino esters from enamines, although certain aspects of this process are, as yet, unexplained

Michigan Production Costs for Tart Cherries by Production Region

The weighted average cost of producing tart cherries in Michigan on a representative farm in 2009 is $0.36/lb. This cost was averaged across the three main production regions in Michigan and weighted by average per acre production for each region as published by the Michigan Agricultural Statistics Service. --Costs vary across the main production regions and by farm size. Costs are about$0.04/lb less for mid-sized farms in Northwest Michigan and $0.08/lb and$0.10/lb in West Central and Southwest Michigan, respectively. --This report was developed through interviews with tart cherry growers and other experts in each of the three main growing regions in 2005 and 2006. Many of the numbers were updated in 2009. --The cost of production calculation is based on estimates of operating costs, harvest costs, and management, interest and tax costs. It also includes an amortized cost of establishing an orchard and employing the land in production (versus some other use). The following tables summarize the cost findings for each of the production regions.Tart cherry, costs, production, Michigan, Agribusiness, Crop Production/Industries, Q100, Q120,

Are factor endowments fate?

In recent theories of comparative development, the role of institutional differences has been crucial. Yet, what explains comparative institutional evolution? We investigate this issue by studying the coffee exporting economies of Latin America. Although homogeneous in many ways, they experienced radically different paths of economic (and political) development, which is conventionally traced to the differential organization of the coffee industry. We show that the different forms that the coffee economy took in the 19th century was critically determined by the legal environment determining access to land, and that different laws resulted from differences in the nature of political competition and the backgrounds of political elites. Our analysis suggests that explanations of institutional differences that stress economic fundamentals can only be part of the story. At least in the economies that we study, while geography, factor endowments and technology are clearly important, their implications for the institutional structure and thus development are conditional on the form that political competition takes in society. For interesting variations in economic outcomes, endowments are not fate.El papel de las diferencias institucionales ha sido crucial en las teorías recientes del desarrollo comparativo. Pero ¿Qué explica las diferencias comparativas en la evolución institucional? En este trabajo investigamos este asunto estudiando las economías exportadoras de café en Latinoamérica. Aunque similares, estas economías experimentaron diferentes modelos de desarrollo económico (y político) convencionalmente explicados en relación con su diferente organización de la industria cafetera. Este artículo muestra que las diferentes formas adoptadas por la economía cafetera en el siglo XIX estuvieron especialmente determinadas por el entorno legal del acceso a la tierra y de las diferentes leyes resultantes de las diferencias en la naturaleza de la competición política y de la formación de las elites políticas. Nuestro análisis sugiere que las explicaciones de diferencia institucional que presionan los fundamentos de la economía pueden ser sólo una parte de la explicación. Al menos en las economías que hemos estudiado, mientras la geografía, la dotación de recursos y la tecnología son claramente importantes en la explicación, sus implicaciones sobre la estructura institucional y, en consecuencia, sobre el desarrollo, dependen de la forma de competición política adoptada por la sociedad. Para las interesantes variaciones de los resultados económicos los recursos no son el destino

Balancing conservation with national development: a socio-economic case study of the alternatives to the Serengeti Road

Developing countries often have rich natural resources but poor infrastructure to capitalize on them, which leads to significant challenges in terms of balancing poverty alleviation with conservation. The underlying premise in development strategies is to increase the socio-economic welfare of the people while simultaneously ensuring environmental sustainability, however these objectives are often in direct conflict. National progress is dependent on developing infrastructure such as effective transportation networks, however roads can be ecologically catastrophic in terms of disrupting habitat connectivity and facilitating illegal activity. How can national development and conservation be balanced? The proposed Serengeti road epitomizes the conflict between poverty alleviation on one hand, and the conservation of a critical ecosystem on the other. We use the Serengeti as an exemplar case-study in which the relative economic and social benefits of a road can be assessed against the ecological impacts. Specifically, we compare three possible transportation routes and ask which route maximizes the socio-economic returns for the people while minimizing the ecological costs. The findings suggest that one route in particular that circumnavigates the Serengeti links the greatest number of small and medium sized entrepreneurial businesses to the largest labour force in the region. Furthermore, this route connects the most children to schools, provisions the greatest access to hospitals, and opens the most fertile crop and livestock production areas, and does not compromise the ecology and tourism revenue of the Serengeti. This route would improve Tanzania’s food security and self-reliance and would facilitate future infrastructure development which would not be possible if the road were to pass through the Serengeti. This case study provides a compelling example of how a detailed spatial analysis can balance the national objectives of poverty alleviation while maintaining ecological integrity

Predicting mortality in HIV-infected children initiating highly active antiretroviral therapy: A risk scoring system for resource-limited settings

Background: Access to highly active antiretroviral therapy (HAART) among HIV-infected children in sub-Saharan Africa is increasing. WHO estimated that 387,500 children were receiving HAART in this region at the end of 2010. Recent studies have demonstrated that children starting HAART in resource-poor countries can achieve similar outcomes to children in resource-rich countries. However, mortality rates remain higher in resource-poor countries, especially during the first six months of therapy. Despite scaled-up HAART programs, no prognostic models predicting risk of death are available for children initiating HAART in resource-limited settings. Current clinical prediction tools for HIV-infected children are derived from pre-HAART data and therefore cannot predict mortality in children on HAART. The purpose of this study was to develop a mortality risk scoring system for HAART-naïve, HIV-infected children beginning therapy in a resource-limited setting. In addition, we have conducted a systematic review of the literature identifying the risk factors associated with early mortality and the causes of early death in children initiating HAART. Methods: Observational data were collected and analyzed from HIV-infected children initiating HAART between December 2004 and April 2012 at Kalembe Lembe Pediatric Hospital and Bomoi Health Care Center in Kinshasa, Democratic Republic of the Congo. Univariate and adjusted Cox proportional hazards models were constructed to assess associations between demographic and clinical characteristics at the time of HAART initiation and mortality. Each variable in the final Cox model received a predictor score. Predictor scores were summed to obtain an overall risk score for each child beginning HAART. The risk scoring system was validated internally using bootstrap resampling techniques. Performance of the final model was measured by Harrell’s C statistic. Results: By April 2012, 1005 children had initiated HAART with 3017.4 child-years of follow-up (median 30.8 months on HAART). One hundred children (10.0%) died at a median of 5.3 months post-HAART initiation, yielding a mortality rate of 3.3 deaths (95% CI: 2.7-4.0) per 100 child-years. The final multivariable model included female gender, anemia, severe malnutrition, presence of HIV symptoms, low total lymphocyte count, and age greater than 5 years. These determinants were highly predictive of mortality (C-statistic=0.81). The discriminative ability of our model was comparable to existing pediatric AIDS survival scores that do not account for HAART (C-statistic=0.84). Conclusions: Mortality risk among children starting HAART in this resource-limited setting can be evaluated using a simple scoring system incorporating several readily available factors. Identifying significant predictors of mortality will help clinicians target modifiable risk factors, like anemia and malnutrition, not addressed by HAART. External validation of this model within pediatric HIV-infected cohorts in other resource-limited settings is needed to confirm its utility in assessing prognosis.Master of Public Healt

NEOWISE: Observations of the Irregular Satellites of Jupiter and Saturn

We present thermal model fits for 11 Jovian and 3 Saturnian irregular satellites based on measurements from the WISE/NEOWISE dataset. Our fits confirm spacecraft-measured diameters for the objects with in situ observations (Himalia and Phoebe) and provide diameters and albedo for 12 previously unmeasured objects, 10 Jovian and 2 Saturnian irregular satellites. The best-fit thermal model beaming parameters are comparable to what is observed for other small bodies in the outer Solar System, while the visible, W1, and W2 albedos trace the taxonomic classifications previously established in the literature. Reflectance properties for the irregular satellites measured are similar to the Jovian Trojan and Hilda Populations, implying common origins.Comment: 17 pages, 3 figures, accepted for publication in Astrophysical Journa

Fusion of Unobtrusive Sensing Solutions for Sprained Ankle Rehabilitation Exercises Monitoring in Home Environments

The ability to monitor Sprained Ankle Rehabilitation Exercises (SPAREs) in home environments can help therapists ascertain if exercises have been performed as prescribed. Whilst wearable devices have been shown to provide advantages such as high accuracy and precision during monitoring activities, disadvantages such as limited battery life and users’ inability to remember to charge and wear the devices are often the challenges for their usage. In addition, video cameras, which are notable for high frame rates and granularity, are not privacy-friendly. Therefore, this paper proposes the use and fusion of privacy-friendly and Unobtrusive Sensing Solutions (USSs) for data collection and processing during SPAREs in home environments. The present work aims to monitor SPAREs such as dorsiflexion, plantarflexion, inversion, and eversion using radar and thermal sensors. The main contributions of this paper include (i) privacy-friendly monitoring of SPAREs in a home environment, (ii) fusion of SPAREs data from homogeneous and heterogeneous USSs, and (iii) analysis and comparison of results from single, homogeneous, and heterogeneous USSs. Experimental results indicated the advantages of using heterogeneous USSs and data fusion. Cluster-based analysis of data gleaned from the sensors indicated an average classification accuracy of 96.9% with Neural Network, AdaBoost, and Support Vector Machine, amongst others