392 research outputs found
The Political Economy of Pork-Barrel Spending
This dissertation consists of five papers which examine the impact pork-barrel spending has on legislative decision-making. In chapter 1, I introduce the theory behind pork-barrel spending, legislative coalitions and other similar topics. In chapter 2, I determine if pork-barrel spending has any impact on state employment levels. I use both a spatial and non-spatial modeling methodology to answer the question. Chapter 3 examines the relationship between the amount of pork-barrel spending appropriated by the Senator and the amount of money the Senator is able to fundraise. Chapter 4 integrates the results from chapter 3 to develop two-stage and three-stage models which estimate electoral success. The fifth and final chapter concludes the dissertation by using the results from the other chapters to determine whether or not pork-barrel spending suffers from the Tragedy of the Commons
Differential requirements for segment polarity genes in wingless signaling
The segment polarity genes wingless and engruiled are required throughout development of Drosophila. During early embryogenesis, these two genes are expressed in adjacent domains, in an inter-dependent way. Later, their expression is regulated by different mechanisms and becomes maintained by auto-regulation. To dissect the genetic requirements for the initial signaling between wingless and engrailed expressing cells, we have previously used a transgenic Drosophila strain that expresses wingless under the control of the heat shock promoter (HS-wg). Focusing on the later phases of wingless and engruiled regulation, we have now extended these studies, using embryos carrying various combinations of segment polarity mutations and the HS-wg transgene. We confirm some of the existing models of regulation of the expression of wingfess and engrailed. In addition, we find that HS-wg embryos require engruifed for induction of ectopic endogenous wingless expression. Signaling from engrailed cells to this novel wingless expression domain is dependent on hedgehog but also on porcupine. We further demonstrate a novel requirement for hedgehog in maintenance of expression of engruiled itself
Menarche delay and menstrual irregularities persist in adolescents with type 1 diabetes
<p>Abstract</p> <p>Background</p> <p>Menarche delay has been reported in adolescent females with type 1 diabetes (T1DM), perhaps due to poor glycemic control. We sought to compare age at menarche between adolescent females with T1DM and national data, and to identify factors associated with delayed menarche and menstrual irregularity in T1DM.</p> <p>Methods</p> <p>This was a cross-sectional study and females ages 12- 24 years (n = 228) with at least one menstrual period were recruited during their outpatient diabetes clinic appointment. The National Health and Nutrition Examination Survey (NHANES) 2001-2006 data (n = 3690) for females 12-24 years were used as a control group.</p> <p>Results</p> <p>Age at menarche was later in adolescent females with T1DM diagnosed prior to menarche (12.81 +/- 0.09 years) (mean+/- SE) (n = 185) than for adolescent females diagnosed after menarche (12.17 0.19 years, <it>p = </it>0.0015) (n = 43). Average age of menarche in NHANES was 12.27 +/- 0.038 years, which was significantly earlier than adolescent females with T1DM prior to menarche (<it>p </it>< 0.0001) and similar to adolescent females diagnosed after menarche (<it>p </it>= 0.77). Older age at menarche was negatively correlated with BMI z-score (r = -0.23 <it>p = </it>0.0029) but not hemoglobin A1c (A1c) at menarche (r = 0.01, <it>p </it>= 0.91). Among 181 adolescent females who were at least 2 years post menarche, 63 (35%) reported usually or always irregular cycles.</p> <p>Conclusion</p> <p>Adolescent females with T1DM had a later onset of menarche than both adolescent females who developed T1DM after menarche and NHANES data. Menarche age was negatively associated with BMI z-score, but not A1c. Despite improved treatment in recent decades, menarche delay and high prevalence of menstrual irregularity is still observed among adolescent females with T1DM.</p
Soil resources, microbial activity, and primary production across an agricultural ecosystem
Includes bibliographical references (pages 169-170).The degree to which soil resource availability is linked to patterns of microbial activity and plant productivity within ecosystems has important consequences for our understanding of how ecosystems are structured and for the management of systems for agricultural production. We studied this linkage in a 48-ha site in southwest Michigan, USA, that had been cultivated and planted to row crops for decades. Prior to seeding the site to genetically identical soybean plants (Glycine max) in early spring, we removed soil samples from ≈600 locations; plant biomass was harvested from these same locations later in the season. Soil samples were analyzed for physical properties (texture, bulk density), chemical properties (moisture, pH, total C, total N, inorganic N), and biological attributes (microbial biomass, microbial population size, respiration potential, and nitrification and N-mineralization potentials). Plant analyses included biomass and C and N contents. Soil resource variability across this long-cultivated site was remarkably high, as was variability in microbial activity and primary productivity. In almost all cases variability exhibited a strong spatially explicit structure: for most properties and processes > 50% of sample variance was spatially dependent at a scale of 5–60 m. Exceptions included microtopography, soil pH, and inorganic P, which were spatially dependent across the entire 1–1200 m range of separation distances examined in this study, and the culturable-bacteria population, which was not spatially autocorrelated at any scale examined. Both topographic relief and soil pH exhibited strongly nested structures, with autocorrelation occurring within two (topography) or more (pH) distinct ranges. Multiple regression analysis showed surprisingly little correlation between biological processes (soybean productivity, soil N turnover, soil respiration), and static soil properties. The best predictor of soybean biomass at late reproductive stages (r2 = 0.42) was a combination of nitrate N, bulk density, inorganic P, N-mineralization rates, and pH. Overall, results suggest a remarkable degree of spatial variability for a pedogenically homogeneous site that has been plowed and cropped mostly as a single field for > 100 yr. Such variability is likely to be generic to most ecosystems and should be carefully evaluated when making inferences about ecological relationships in these systems and when considering alternative sampling and management strategies
Pediatric diabetes consortium T1D New Onset ( NeOn ) study: clinical outcomes during the first year following diagnosis
Objective There have been few prospective, multicenter studies investigating the natural history of type 1 diabetes ( T1D ) from the time of diagnosis. The objective of this report from the Pediatric Diabetes Consortium ( PDC ) T1D New Onset ( NeOn ) study was to assess the natural history and clinical outcomes in children during the first year after diagnosis of T1D . Research design and methods: Clinical measures from the first year following diagnosis were analyzed for 857 participants (mean age 9.1 yr, 51% female, 66% non‐Hispanic White) not participating in an intervention study who had a HbA1c result at 12 months. Results Mean HbA1c ± SD was 102 ± 25 mmol/mol (11.4 ± 2.3%) at diagnosis, 55 ± 12 mmol/mol (7.2 ± 1.1%) at 3 months, 56 ± 15 mmol/mol (7.3 ± 1.3%) at 6 months and 62 ± 16 mmol/mol (7.8 ± 1.5%) at 12 months from diagnosis. A severe hypoglycemic ( SH ) event occurred in 31 (4%) participants (44 events, 5.2 events per 100 person‐years). Diabetic ketoacidosis ( DKA ) not including diagnosis occurred in 10 (1%) participants (13 events, 1.5 events per 100 person‐years). Conclusions After onset of T1D , mean HbA1c reaches its nadir at 3–6 months with a gradual increase through 12 months. SH and DKA are uncommon but still occur during the first year with T1D . Data from large cohorts, such as the PDC T1D NeOn study, provide important insights into the course of T1D during the first year following diagnosis, which will help to inform the development of models to target future interventions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107374/1/pedi12068.pd
Clinical outcomes in youth beyond the first year of type 1 diabetes: Results of the Pediatric Diabetes Consortium (PDC) type 1 diabetes new onset (NeOn) study
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138914/1/pedi12459.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138914/2/pedi12459_am.pd
Predictors of Lost to Follow-Up among Children with Type 2 Diabetes
Background/Aims: Youth with type 2 diabetes (T2D) have poor compliance with medical care. This study aimed to determine which demographic and clinical factors differ between youth with T2D who receive care in a pediatric diabetes center versus youth lost to follow-up for >18 months. Methods: Data were analyzed from 496 subjects in the Pediatric Diabetes Consortium registry. Enrollment variables were selected a priori and analyzed with univariable and multivariable logistic regression models. Results: After a median of 1.3 years from enrollment, 55% of patients were lost to follow-up. The final model included age, race/ethnicity, parent education, and estimated distance to study site. The odds ratio (99% confidence interval) of loss to follow-up was 2.87 (1.34, 6.16) for those aged 15 to <18 years versus those aged 10 to <13 years and 6.57 (2.67, 16.15) for those aged ≥18 years versus those aged 10 to <13 years. Among patients living more than 50 miles from the clinic, the odds ra tio of loss to follow-up was 3.11 (1.14, 8.49) versus those living within 5 miles of the site. Conclusion: Older adolescents with T2D are more likely to be lost to follow-up, but other socioeconomic factors were not significant predictors of clinic follow-up
An integrated system for autonomous robotics manipulation
We describe the software components of a robotics system designed to autonomously grasp objects and perform dexterous manipulation tasks with only high-level supervision. The system is centered on the tight integration of several core functionalities, including perception, planning and control, with the logical structuring of tasks driven by a Behavior Tree architecture. The advantage of the implementation is to reduce the execution time while integrating advanced algorithms for autonomous manipulation. We describe our approach to 3-D perception, real-time planning, force compliant motions, and audio processing. Performance results for object grasping and complex manipulation tasks of in-house tests and of an independent evaluation team are presented
Ultra Large Castings to Produce Low Cost Aluminum Vehicle Structures
Through a cooperative effort with the U.S. Department of Energy (DOE) Office of Heavy Vehicle Technologies (OHVT), Alcoa is developing a casting process to produce ultra large thin wall components. The casting process is a low pressure, metal mold, multiport injection vertical casting process. The specific system for demonstration of the process is located at Alcoa's Technology Center and will be capable of producing parts extending 3 M long, 1.7 M wide and 0.4 M high. For example, single castings of car floor pan frames or side wall aperture structures are candidates for this installation. This shall provide a major opportunity to reduce the cost of lightweight transportation vehicle structures by (a) reducing the components or part count and (b) reducing the cost of assembly. To develop and demonstrate the process, an inner panel of the Chrysler minivan liftgate will be first produced on this system. Through computer analyses, the cast inner panel design was developed to satisfy both structural performance and casting process requirements. Currently, this is an 11 part assembly of steel components. At the time of this abstract, the numerous system components are in various phases of fabrication and site preparation is fully underway, with system shakedown beginning in the second quarter of 1999. Successful demonstration of caster system operation is anticipated to occur during the third quarter and production of a high quality product during the fourth quarter. Although the process is targeted toward reducing the cost of lightweight trucks, buses and autos, consideration is being given to application in the aircraft industry
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