1,703 research outputs found
Effects of Mode of Cedar (Juniperus ashei) Removal on Grassland Species Composition in the Texas Hill Country
Globally, arid and semi-arid grassland ecosystems are being invaded by woody tree and shrub species. Over the past 200 years in the United States in central and western Texas and throughout the Southwest such an invasion has altered the landscape from dominant C4 perennial bunchgrass vegetation to closed canopy forests of mainly Juniperus spp. and Prosopis spp. There have been widespread campaigns to remove these woody species to increase grassland acreage and biodiversity for forage and as wildlife habitat. Nonetheless, removal efforts have been foiled due to the invasion by an exotic species introduced to improve rangelands. King Ranch Bluestem (a.k.a. KR bluestem, Bothriochloa ischaemum (L.) Keng var. songarica), is a highly invasive, non-native, C4, perennial grass. The invasive nature and competitive dynamics of this species are under investigation by many researchers because it threatens native biodiversity and rangeland and wildlife habitat health. My study is designed to assess change in herbaceous grassland communities following Juniperus ashei clearing on the eastern Edwards Plateau of Central Texas. I quantify differences in herbaceous cover and diversity in grassland ecosystems as a function of modes of J. ashei removal (chainsaw, bulldozer, or Cedar Eater), and post-removal land management (seeding with native grass mixtures and lopping of J. ashei seedlings.). The ultimate goal of the study is to provide landowners of Central Texas with practical information for how to improve grassland habitat quality for wildlife while preventing non-native species invasions. Results of the study suggest that removal of J. ashei with a chainsaw followed by periodic lopping of saplings is the most effective tool for grassland restoration
Measuring diet in primary school children aged 8-11 years: validation of the Child and Diet Evaluation Tool (CADET) with an emphasis on fruit and vegetable intake.
Background/Objectives:The Child And Diet Evaluation Tool (CADET) is a 24-h food diary that measures the nutrition intake of children aged 3-7 years, with a focus on fruit and vegetable consumption. Until now CADET has not been used to measure nutrient intake of children aged 8-11 years. To ensure that newly assigned portion sizes for this older age group were valid, participants were asked to complete the CADET diary (the school and home food diary) concurrently with a 1-day weighed record. Subjects/Methods:A total of 67 children with a mean age of 9.3 years (s.d.: ± 1.4, 51% girls) participated in the study. Total fruit and vegetable intake in grams and other nutrients were extracted to compare the mean intakes from the CADET diary and Weighed record using t-tests and Pearson's r correlations. Bland-Altman analysis was also conducted to assess the agreement between the two methods. Results: Correlations comparing the CADET diary to the weighed record were high for fruit, vegetables and combined fruit and vegetables (r=0.7). The results from the Bland-Altman plots revealed a mean difference of 54âg (95% confidence interval: -88, 152) for combined fruit and vegetables intake. CADET is the only tool recommended by the National Obesity Observatory that has been validated in a UK population and provides nutrient level data on children's diets. Conclusions:The results from this study conclude that CADET can provide high-quality nutrient data suitable for evaluating intervention studies now for children aged 3-11 years with a focus on fruit and vegetable intake
Fine structure and magneto-optics of exciton, trion, and charged biexciton states in single InAs quantum dots emitting at 1.3 um
We present a detailed investigation into the optical characteristics of
individual InAs quantum dots (QDs) grown by metalorganic chemical vapor
deposition, with low temperature emission in the telecoms window around 1300
nm. Using micro-photoluminescence (PL) spectroscopy we have identified neutral,
positively charged, and negatively charged exciton and biexciton states.
Temperature-dependent measurements reveal dot-charging effects due to
differences in carrier diffusivity. We observe a pronounced linearly polarized
splitting of the neutral exciton and biexciton lines (~250 ueV) resulting from
asymmetry in the QD structure. This asymmetry also causes a mixing of the
excited trion states which is manifested in the fine structure and polarization
of the charged biexciton emission; from this data we obtain values for the
ratio between the anisotropic and isotropic electron-hole exchange energies of
(Delta1)/(Delta0)= 0.2--0.5. Magneto-PL spectroscopy has been used to
investigate the diamagnetic response and Zeeman splitting of the various
exciton complexes. We find a significant variation in g-factor between the
exciton, the positive biexciton, and the negative biexciton; this is also
attributed to anisotropy effects and the difference in lateral extent of the
electron and hole wavefunctions.Comment: 7 pages, 6 figures, submitted to Phys. Rev.
Dietary value for money? Investigating how the monetary value of diets in the National Diet and Nutrition Survey (NDNS) relate to dietary energy density
Estimating the monetary value of individualsâ diets allows investigation into how costs relate to dietary quality. A number of studies(1â2), including one in Scotland(3), have reported a strong negative relationship between diet costs and energy density. Most studies of this type neglect to address the issue of mathematical coupling, where energy is both the numerator in the energy density variable (kJ/g) and the denominator in energy-adjusted diet cost (e.g. E/10 MJ). As a result, the findings could be reflecting a mathematical relationship(4).
This study investigated how estimated diet costs of NDNS adults relate to dietary energy density using the âresidualsâ regressionmethod to account for energy. Diet diary information from 2008â2010 was matched to an in-house database of national average (2004) food prices (the DANTE cost database) to assign a cost to each food and non-alcoholic beverage consumed. Mean daily diet costs and costs per 10 MJ were calculated for each participant. Energy density (g/kJ) was derived from foods and milk.
The sample median diet cost was ÂŁ2.84 per day (IQR ÂŁ2.27, ÂŁ3.64), or ÂŁ4.05 per 10MJ (ÂŁ3.45, ÂŁ4.82). Values for energy density, food energy, and diet costs by quintiles of dietary energy density (1 = least energy dense) are presented in the table. Adjusted linear regression found a strong negative relationship: additional standard deviation above the diet cost expected for a given energy intake (the residual), there was an associated decrease in energy density of 0.46kJ/g (95% CI - 0.53, - 0.38, p<0.001).
This is the first time individual-level diet costs have been characterized for a representative British population. These diet costs represent the inherent value of the diet, and are not comparable to UK expenditure data. The analyses confirm a diet cost-energy density link that is not due to mathematical artefact, and suggest that those consuming more energy-dense diets are achieving more kilojoules for their money
Community Dialogues for Racial Healing: Participant Handouts
Miss RECoP launched in 2016 and continues to be active throughout the state of Mississippi. This dialogue process is a product of their work and has been used throughout the state to promote understanding and healing among different racial/ethnic people. Community Dialogues for Racial Healing now brings this vital work to a national scope to promote healing in other areas of the nation.This is a packet of handouts that go along with the Community Dialogues for Racial Healing: Community Liaison Support Manua
gem-Dibromocyclopropanes and enzymatically derived cis-1,2-dihydrocatechols as building blocks in alkaloid synthesis
The application of the title building blocks, the 6,6-dibromobicyclo[3.1.0]hexanes
and the cis-1,2-dihydrocatechols, to the total synthesis of crinine and lycorinine alkaloids is
described.We thank the Australian Research Council and the Institute of Advanced Studies for generous financial
support
Maternal iron status in early pregnancy and birth outcomes : insights from the Baby's Vascular health and Iron in Pregnancy study
Date of Acceptance: 16/03/2015 Acknowledgements N. A. A. was funded by a Wellcome Trust Research Training Fellowship (WT87789). H. J. M. and H. E. H. are supported by the Scottish Governmentâs Rural and Environment Science and Analytical Services. N. A. B. S. is supported by Cerebra. The authorsâ contributions are as follows: N. A. A. was responsible for organising the study conduct, data collection and database management, performed the statistical analysis, interpreted the results and drafted the paper. N. A. A., N. A. B. S., J. E. C., H. J. M. and D. C. G. contributed to the study concept and design, and interpretation of results. H. J. M. and H. E. H. analysed the laboratory samples. J. E. C. and D. C. G. provided advice on statistical strategy and analysis. All authors have fully participated in the reporting stage and have critically reviewed and approved the final draft of the paper. The authors declare no conflict of interestPeer reviewedPublisher PD
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Picoliter-volume inkjet printing into planar microdevice reservoirs for low-waste, high-capacity drug loading.
Oral delivery of therapeutics is the preferred route for systemic drug administration due to ease of access and improved patient compliance. However, many therapeutics suffer from low oral bioavailability due to low pH and enzymatic conditions, poor cellular permeability, and low residence time. Microfabrication techniques have been used to create planar, asymmetric microdevices for oral drug delivery to address these limitations. The geometry of these microdevices facilitates prolonged drug exposure with unidirectional release of drug toward gastrointestinal epithelium. While these devices have significantly enhanced drug permeability in vitro and in vivo, loading drug into the micron-scale reservoirs of the devices in a low-waste, high-capacity manner remains challenging. Here, we use picoliter-volume inkjet printing to load topotecan and insulin into planar microdevices efficiently. Following a simple surface functionalization step, drug solution can be spotted into the microdevice reservoir. We show that relatively high capacities of both topotecan and insulin can be loaded into microdevices in a rapid, automated process with little to no drug waste
Phosphorus forms and concentrations in soils under different land use in southwestern Saskatchewan
Non-Peer ReviewedPhosphorus (P) is an essential nutrient for all organisms. Insufficient or poorly available P can limit crop growth, requiring P fertilization. However, excess P can move from land to water, impairing water quality. Balancing P fertilization to maximize crop growth while limiting P loss requires a detailed knowledge of P forms and cycling. Different land use practices are expected to alter P cycling through differences in microbial populations, P inputs from vegetation and fertilizer, and management practices that affect soil chemical and physical properties. Understanding P cycling under different land uses can help to improve P use efficiency in agriculture. Presented here are the preliminary results of a research project investigating P forms and cycling in soils under different land uses in southwestern Saskatchewan
Geography of Diet in the UK Womenâs Cohort Study: A Cross-Sectional Analysis
Diet can influence health outcomes and chronic disease risk, therefore a better understanding of factors influencing diet is important in promotion of healthier dietary choices. Many factors influence food choice, including the environment in which we live. This study aims to explore differences in dietary pattern consumption by two spatial measures: Government Office Region (a large regional unit of geography) and Output Area Classification (a small area geography combined with demographic characteristics). A cross-sectional analysis using data from the UK Womenâs Cohort Study was carried out. This cohort included ~35000 middle aged women recruited between 1995 and 1999. Dietary patterns were derived using a k-means cluster analysis from diet data collected using a validated 217 item Food Frequency Questionnaire. Multinomial logit regression was used to test whether the area in which the women live, predicts their dietary pattern consumption. Results show that dietary patterns vary significantly by both spatial measures. The Government Office Region, the North West of England has the highest proportion of individuals consuming the least healthy, monotonous diets, while Greater London has the highest proportion of vegetarian diets. Individuals living in Supergroups âCountrysideâ and âProspering Suburbsâ consume healthier, more diverse diets. Those in âConstrained by Circumstanceâ and âBlue Collar Communitiesâ consume monotonous, less healthy diets. Using a combination of spatial scales such as Government Office Region and Output Area Classification Supergroup could have a beneficial impact on targeting of public health dietary interventions and subsequent health
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