Irrigated Acreage Projections in Georgia

Irrigated acreage is an important indicator for agricultural water demand which is a major category of water use. Three methodologies were applied in this study to project irrigated acreage of major crops in Georgia from 2010 to 2050. These three methodologies show consistent results. Total irrigated acreage of major crops in Georgia is projected to increase for the next 40 years. The acreage projection results provide useful information for Georgia agricultural policy makers and farmers. However, the methodologies used in the study have some limitations. They can only be used under certain assumptions. Thus, better methodologies are needed for future related research.Irrigated acreage projection, acreage response elasticities, Crop Production/Industries, Environmental Economics and Policy, Farm Management, Resource /Energy Economics and Policy,

Land Use Change and Ecosystem Valuation in North Georgia

A model of land allocation at the aggregate watershed level was developed assuming profit/net benefit maximization under risk neutrality. The econometric land use model was analyzed as an equation by equation SURE model as all the independent variables were the same for both equations. In analyzing effect of land use change on water quality, we took year 2005 as our baseline and postulated three land use scenarios. We applied Benefit Transfer techniques to value water quality changes resulting from land use change and estimated lower bounds for WTP to improve water quality to meet the FCB criterion for drinking water supply and fishing waters and BOD (DO) criteria for fishing waters. Water quality modeling revealed that land use change would result in increased runoff, and associated increase in FCB and BOD/DO violations. But the BOD/DO violations could be curtailed by managing urban growth as evidenced absence of BOD violations in the managed growth scenario. Our study finds there may be problems of FCB under all postulated future land use scenarios. The findings also support existing literature that there are problems with FCB violation in the study area at the moment. Finally, it seems that the people of UCRB would be willing to pay a lower bound value between USD 15,785,740 and USD 16,141,230 per year to create and maintain quality standards for fishing and drinking water supply.Ecosystem, Economic value, North Georgia, land use, land use change, fish, water quality, structural time series, willingness to pay, benefit transfer, forecasting, vector autoregression, Upper Chattahoochee River, Environmental Economics and Policy, Land Economics/Use,

Assessing the Effects of Climate Change on Farm Production and Profitability: Dynamic Simulation Approach

In this paper, a dynamic optimization model was developed to simulate how farm-level realized price and profitability respond to yield change which was induced by climate change. Producers' acreage response was included in the dynamic model considering crop rotation effect. In the crop rotation model, a modified Bellman equation was used to dynamically optimize the net present value of farm profit for a five-year interval. This simulation process was repeated through the year 2050. Then yield, price, and acreage response were compiled to generate realized profit. Results generally indicated that reduction in crop yields due to climate change results in reduced farm profitability for most of the states studied. Predicted climate change is more likely to pose a problem for agricultural production and profitability in the southern U.S. states as compared to the northern U.S. states. Our results also suggest that acreage response alone is not sufficient to ameliorate the potential negative effects of global climate change on agricultural production and profitability. The results of this research are expected to provide a foundation for future related research to aid producers' crop rotation decisions in an unstable price environment.Dynamic simulation model, Acreage response, Crop rotation, Expected price, Realized price, Agricultural Finance, Crop Production/Industries, Environmental Economics and Policy, Farm Management, Land Economics/Use, Production Economics, Productivity Analysis, Risk and Uncertainty,

Principal Component Analysis of Crop Yield Response to Climate Change

The objective of this study is to compare the effects of climate change on crop yields across different regions. A Principal Component Regression (PCR) model is developed to estimate the historical relationships between weather and crop yields for corn, soybeans, cotton, and peanuts for several northern and southern U.S. states. Climate change projection data from three climate models are applied to the estimated PCR model to forecast crop yield response. Instead of directly using weather variables as predictor variables, the PCR model uses weather indices transformed from original weather variables by the Principal Component Analysis (PCA) approach. A climate change impact index (CCII) is developed to compare climate change effects across different regions. The key contribution of our study is in identifying a different climate change effects in crop yields in different U.S. states. Specifically, our results indicate that future warmer weather will have a negative impact for southern U.S. counties, while it has insignificant impact for northern U.S. counties in the next four decades.Principal component regression, Crop yield response, Climate change., Crop Production/Industries,

Social Security Research at the University of Michigan Retirement and Disability Research Center

In 1998, the Social Security Administration established the Retirement Research Consortium to encourage research on topics related to Social Security and the well-being of older Americans, and to foster communication between the academic and policy communities. The Michigan Retirement Research Center (MRRC) participated in the Consortium from its inception until 2019, when the MRRC expanded and became the Michigan Retirement and Disability Research Center. This article surveys a selection of the MRRC’s output over its second 10 years (2008–2017), summarizes its innovative use of new data sources, and highlights several key themes in the center’s research contributions

Sex-Specific Outcomes After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Background: Despite the significant difference between men and women in incidence of anterior cruciate ligament (ACL) injuries, there is a paucity of consistent information on the influence of patient sex on outcomes after ACL reconstruction. A previous meta-analysis has demonstrated that female patients have worse outcomes with regard to laxity, revision rate, Lysholm score, and Tegner activity score and are less likely to return to sports (RTS). Purpose: To conduct a systematic review and meta-analysis to evaluate and compare sex-specific outcomes after ACL reconstruction. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed using PubMed, PubMed Central, Embase, OVID, and Cochrane databases per PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The following search terms were used: “anterior cruciate ligament reconstruction” OR “ACL reconstruction” OR “anterior cruciate ligament” OR “ACL” AND “gender” OR “sex” OR “male” OR “female” AND “outcome” AND “2015-Present” to gather all relevant articles between 2015 and 2020. A risk-of-bias assessment and quality assessment was conducted on included studies. Results: Of 9594 studies initially identified, 20 studies with 35,935 male and 21,455 female patients were included for analysis. The 7 studies reporting International Knee Documentation Committee (IKDC) scores showed that male patients had statistically significantly higher postoperative scores (mean difference, 3.02 [95% CI, 1.19-4.84]; P< .01; I 2 = 66%), and 7 studies that reported the rate of ACL revision showed there was no significant difference between male and female patients (odds ratio, 0.85 [95% CI, 0.45-1.60]; P = .61; I 2 = 94%). The 7 studies that reported rates of rerupture showed that males were significantly more likely than females to have a graft rerupture (odds ratio, 1.35 [95% CI, 1.22-1.50]; P < .01; I 2 = 0%). Male patients reported a higher RTS rate than did their female counterparts (59.82% compared with 42.89%); however, no formal statistical analysis could be done because of the variability in reporting techniques. Conclusion: Male and female patients with ACL injuries demonstrated similar outcomes regarding their rates of revision; however, male patients were found to have statistically significantly higher postoperative IKDC scores but at the same time higher rerupture rates. Our findings suggest that sex-based differences in outcomes after ACL reconstruction vary based on which metric is used. These results must be considered when counseling patients with ACL injuries

Comparing Sex-Specific Outcomes After Rotator Cuff Repair: A Meta-analysis

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Background: Rotator cuff repair (RCR) is a well-studied procedure. However, the impact of patient sex on outcomes after RCR has not been well studied. Purpose: To conduct a systematic review and meta-analysis of sex-based differences in outcomes after RCR and to record what proportion of studies examined this as a primary or secondary purpose. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed using multiple databases according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were included if they were written in English, performed on humans, consisted of patients who underwent RCR, evaluated at least 1 of the selected outcomes based on patient sex, and had statistical analysis available for their sex-based claim. Excluded were case reports, review studies, systematic reviews, cadaveric studies, and studies that did not report at least 1 sex-specific outcome or included certain other injuries associated with a rotator cuff injury. Results: Of 9998 studies screened and 1283 full-text studies reviewed, 11 (0.11%) studies with 2860 patients (1549 male and 1329 female) were included for quantitative analysis. None of these 11 studies examined the impact of patient sex on outcomes after RCR as a primary outcome. Postoperative Constant-Murley scores were analyzed for 7 studies. Male patients had a postoperative Constant-Murley score of 76.77 ± 15.94, while female patients had a postoperative Constant-Murley score of 69.88 ± 17.02. The random-effects model showed that male patients had significantly higher scores than female patients, with a mean difference of 7.33 (95% CI, 5.21-9.46; P < .0001). Analysis of retear rates in 5 studies indicated that there was no difference in the retear rate between sexes (odds ratio, 0.91 [95% CI, 0.49-1.67]). Conclusion: Female patients had lower postoperative Constant-Murley scores compared with male patients, but there was no difference in the retear rate. However, these results were based on an analysis of only 11 studies. The paucity of studies examining the impact of sex suggests that more research is needed on the impact of patient sex on outcomes after RCR

A Genomic Pathway Approach to a Complex Disease: Axon Guidance and Parkinson Disease

While major inroads have been made in identifying the genetic causes of rare Mendelian disorders, little progress has been made in the discovery of common gene variations that predispose to complex diseases. The single gene variants that have been shown to associate reproducibly with complex diseases typically have small effect sizes or attributable risks. However, the joint actions of common gene variants within pathways may play a major role in predisposing to complex diseases (the paradigm of complex genetics). The goal of this study was to determine whether polymorphism in a candidate pathway (axon guidance) predisposed to a complex disease (Parkinson disease [PD]). We mined a whole-genome association dataset and identified single nucleotide polymorphisms (SNPs) that were within axon-guidance pathway genes. We then constructed models of axon-guidance pathway SNPs that predicted three outcomes: PD susceptibility (odds ratio = 90.8, p = 4.64 × 10−38), survival free of PD (hazards ratio = 19.0, p = 5.43 × 10−48), and PD age at onset (R2 = 0.68, p = 1.68 × 10−51). By contrast, models constructed from thousands of random selections of genomic SNPs predicted the three PD outcomes poorly. Mining of a second whole-genome association dataset and mining of an expression profiling dataset also supported a role for many axon-guidance pathway genes in PD. These findings could have important implications regarding the pathogenesis of PD. This genomic pathway approach may also offer insights into other complex diseases such as Alzheimer disease, diabetes mellitus, nicotine and alcohol dependence, and several cancers

Zero Frequency Current Noise for the Double Tunnel Junction Coulomb Blockade

We compute the zero frequency current noise numerically and in several limits analytically for the coulomb blockade problem consisting of two tunnel junctions connected in series. At low temperatures over a wide range of voltages, capacitances, and resistances it is shown that the noise measures the variance in the number of electrons in the region between the two tunnel junctions. The average current, on the other hand, only measures the mean number of electrons. Thus, the noise provides additional information about transport in these devices which is not available from measuring the current alone.Comment: 33 pages, 10 figure

Re-examining the effects of verbal instructional type on early stage motor learning

The present study investigated the differential effects of analogy and explicit instructions on early stage motor learning and movement in a modified high jump task. Participants were randomly assigned to one of three experimental conditions: analogy, explicit light (reduced informational load), or traditional explicit (large informational load). During the two-day learning phase, participants learned a novel high jump technique based on the ‘scissors’ style using the instructions for their respective conditions. For the single-day testing phase, participants completed both a retention test and task-relevant pressure test, the latter of which featured a rising high-jump-bar pressure manipulation. Although analogy learners demonstrated slightly more efficient technique and reported fewer technical rules on average, the differences between the conditions were not statistically significant. There were, however, significant differences in joint variability with respect to instructional type, as variability was lowest for the analogy condition during both the learning and testing phases, and as a function of block, as joint variability decreased for all conditions during the learning phase. Findings suggest that reducing the informational volume of explicit instructions may mitigate the deleterious effects on performance previously associated with explicit learning in the literature