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[Objective] Crops often suffer from interval drought and rehydration (rainfall or irrigation) during the whole growth period, especially in arid and semi-arid areas. Under drought stress, the growth and development of crops are inhibited, and the yield is reduced; meanwhile, the plants drought tolerance will be induced. In order to compensate loss of yield or growth induced by drought stress, crop often shows compensatory after rehydration, which produces compensation or even over compensation effect on yield. The compensation effect of post drought is the result of crop’s positive response to drought stress and compensatory growth after rehydration. It can effectively improve crop yield and water use efficiency in crop production in arid areas. [Methods] Source sink relationship is widely used to explain the crop yield formation, and regulating the source sink relationship is one of key way to improve crop yield. The compensation effect of post drought is highly related to the source sink response of crops. Based on the current research progress, this paper tries to explain the compensation effect of post drought in source and sink way. [Results] Under the drought stress, in the source, the stomata were closed, photosynthesis was decreased and soluble carbohydrate accumulation was increased, while sink activity was often increased. After rehydration, the metabolism of soluble carbohydrate in the source (leaf) was enhanced, which enhanced the photosynthesis and the ability of carbohydrate synthesis; meanwhile, the sink activity (grain) was maintained at a high level, and the rate of assimilate unloading and accumulation was accelerated; the assimilate in the flow remained at a high level. During this process, the activities of sucrose invertase (INV), cell wall invertase (CW-INV) and fructan exohydrolases (1-FEH w3) play important roles in the source sink response to the compensation effect of post-drought. [Conclusion] This paper integrated the mechanism of compensation effect of post drought in the perspective of source sink relationship, which provides a theoretical basis for understanding the mechanism of compensation effect of post drought and improving crop water efficient in arid areas.

Polyploid plants often exhibit enhanced stress tolerance. Switchgrass is a perennial rhizomatous bunchgrass that is considered ideal for cultivation in marginal lands, including sites with saline soil. In this study, we investigated the physiological responses and transcriptome changes in the octoploid and tetraploid of switchgrass (Panicum virgatum L. 'Alamo') under salt stress. We found that autoploid 8× switchgrass had enhanced salt tolerance compared with the amphidiploid 4× precursor, as indicated by physiological and phenotypic traits. Octoploids had increased salt tolerance by significant changes to the osmoregulatory and antioxidant systems. The salt-treated 8× Alamo plants showed greater potassium (K+) accumulation and an increase in the K+/Na+ ratio. Root transcriptome analysis for octoploid and tetraploid plants with or without salt stress revealed that 302 upregulated and 546 downregulated differentially expressed genes were enriched in genes involved in plant hormone signal transduction pathways and were specifically associated with the auxin, cytokinin, abscisic acid, and ethylene pathways. Weighted gene co-expression network analysis (WGCNA) detected four significant salt stress-related modules. This study explored the changes in the osmoregulatory system, inorganic ions, antioxidant enzyme system, and the root transcriptome in response to salt stress in 8× and 4× Alamo switchgrass. The results enhance knowledge of the salt tolerance of artificially induced homologous polyploid plants and provide experimental and sequencing data to aid research on the short-term adaptability and breeding of salt-tolerant biofuel plants. [ABSTRACT FROM AUTHOR]

Context: Community health centers (CHCs) provide essential access to a primary care medical home for the uninsured, especially in rural communities with no other primary care safety net. CHCs could potentially reduce uninsured emergency department (ED) visits in rural communities. Purpose: We compared uninsured ED visit rates between rural counties in Georgia that have a CHC clinic site and counties without a CHC presence. Methods: We analyzed data from 100% of ED visits occurring in 117 rural (non-metropolitan statistical area [MSA]) counties in Georgia from 2003 to 2005. The counties were classified as having a CHC presence if a federally funded (Section 330) CHC had a primary care delivery site in that county throughout the study period. The main outcome measure was uninsured ED visit rates among the uninsured (all-cause ED visits and visits for ambulatory care sensitive conditions). Poisson regression models were used to examine the relationship between ED rates and the presence of a CHC. To ensure that the effects were unique to the uninsured population, we ran similar analyses on insured ED visits. Findings: Counties without a CHC primary care clinic site had 33% higher rates of uninsured all-cause ED visits per 10,000 uninsured population compared with non-CHC counties (rate ratio [RR] 1.33, 95% confidence interval [CI] 1.11-1.59). Higher ED visit rates remained significant (RR 1.21, 95% CI 1.02-1.42) after adjustment for percentage of population below poverty level, percentage of black population, and number of hospitals. Uninsured ED visit rates were also higher for various categories of diagnoses, but remained statistically significant on multivariate analysis only for ambulatory care sensitive conditions (adjusted RR = 1.22, 95% CI 1.01-1.47). No such relationship was found for ED visit rates of insured patients (RR 1.06, 95% CI 0.92-1.22). Conclusions: The absence of a CHC is associated with a substantial excess in uninsured ED visits in rural counties, an excess not seen for ED visit rates among the insured. (Contains 4 tables.

To explore racial-ethnic disparities in adverse pregnancy outcomes among Medicaid recipients, and to estimate excess Medicaid costs associated with the disparities. Cross-sectional study of adverse pregnancy outcomes and Medicaid payments using data from Medicaid Analytic eXtract files on all Medicaid enrollees in fourteen southern states. Compared to other racial and ethnic groups, African American women tended to be younger, more likely to have a Cesarean section, to stay longer in the hospital and to incur higher Medicaid costs. African-American women were also more likely to experience preeclampsia, placental abruption, preterm birth, small birth size for gestational age, and fetal death/stillbirth. Eliminating racial disparities in adverse pregnancy outcomes (not counting infant costs), could generate Medicaid cost savings of $114 to $214 million per year in these 14 states. Despite having the same insurance coverage and meeting the same poverty guidelines for Medicaid eligibility, African American women have a higher rate of adverse pregnancy outcomes than White or Hispanic women. Racial disparities in adverse pregnancy outcomes not only represent potentially preventable human suffering, but also avoidable economic costs. There is a significant financial return-on-investment opportunity tied to eliminating racial disparities in birth outcomes. With the Affordable Care Act expansion of Medicaid coverage for the year 2014, Medicaid could be powerful public health tool for improving pregnancy outcomes. Keywords Disparities * Medicaid * Economic burden * Adverse maternal-child health outcomes and eliminating disparities, Introduction Complications of pregnancy and adverse perinatal outcomes affect 13-20% of women in the United States every year [1-3]. These adverse pregnancy outcomes not only include maternal outcomes such as [...]