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75 results on '"Qian M"'

2. Low-cost soybean input bundles impact women farmers’ subsistence livelihood traps: evidence from Ghana

Author

Kathleen Ragsdale, Mary R. Read-Wahidi, Qian M. Zhou, Kerry Clark, Mawuli A. K. Asigbee, Courtney Tamimie, and Peter Goldsmith

Subjects
mental disorders, food and beverages, Development, Agronomy and Crop Science, Food Science
Abstract

The Soybean Uptake and Network Survey was administered to a random sample of 832 smallholder male and female farmers in northern Ghana to explore gender and other factors related to soybean production. We investigated the effect of receiving a Soybean Success Kit (i.e., certified seed, fertilizer, inoculum) on soybean yield and income from soybean, controlling for factors such as gender. This analysis includes farmers who 1) resided in districts where Kits were distributed, 2) planted soybean in the past 12 months, and 3) for whom we had complete information for district and gender (n = 371). When results were disaggregated by gender among Kit recipients, average soybean yield (ASY) for males was 108% and average soybean income (ASI) was 97% of that for females. When results were disaggregated by gender among Kit non-recipients, ASY for males was 142% and ASI was 147% of that for females. When results for males were disaggregated by whether the respondent received a Kit, ASY for male Kit recipients was 113% and ASI was 112% of that for male non-recipients. When results for females were disaggregated by whether the respondent received a Kit, ASY for female Kit recipients was 148% and ASI was 170% of that for female non-recipients. These results suggest that providing smallholder female farmers with access to low-cost (˂USD6) input bundles to which they customarily have little or no access can help eliminate the gender gap in agricultural productivity. These results may be applicable to other sub-Saharan Africa countries, where targeting smallholder female farmers as input bundle beneficiaries may positively impact agricultural productivity.

Published
2022

5. Goodness-of-fit test of copula functions for semi-parametric univariate time series models

Author

Huazhen Lin, Qian M. Zhou, and Shulin Zhang

Subjects
Statistics and Probability, Goodness of fit, Ratio test, Univariate, Applied mathematics, Statistics, Probability and Uncertainty, Time series, Cross-validation, Statistical hypothesis testing, Semiparametric model, Copula (probability theory), Mathematics
Abstract

In this paper, we propose a goodness-of-fit test, named pseudo “in-and-out-of-likelihood” (PIOL) ratio test, to check for misspecification in semi-parametric copula models for univariate time series. The proposed test extends the idea of the IOS test by Presnell and Boos (J Am Stat Assoc 99:216–227, 2004) and PIOS test by Zhang et al. (J Econom, 193:215–233, 2016), which are problematic for direct application to univariate time series. The PIOL test provides an integrated framework for both independent data and time series data. In addition, an approximation method is implemented to alleviate the computational burden of calculating the test statistics. Asymptotic properties of the proposed test statistics are discussed. The finite-sample performance is examined through simulation studies. We also demonstrate the proposed method through the analysis of a time series of daily transactions of Apple trade.

Published
2020

24. Multi-contrast high spatial resolution black blood inner volume three-dimensional fast spin echo MR imaging in peripheral vein bypass grafts

Author

Mark A. Creager, Qian M. Zhou, Amanda G. Whitmore, Christopher D. Owens, Robert V. Mulkern, Nichole Wake, Michael S. Conte, Frank J. Rybicki, Dimitrios Mitsouras, Marie Gerhard-Herman, and Tianxi Cai

Subjects
Male, medicine.medical_specialty, Time Factors, Contrast Media, Article, Magnetic resonance angiography, Veins, Imaging, Three-Dimensional, Predictive Value of Tests, High spatial resolution, medicine, Humans, Radiology, Nuclear Medicine and imaging, Prospective Studies, Ultrasonography, Interventional, Vascular Patency, Cardiac imaging, Aged, Peripheral Vascular Diseases, medicine.diagnostic_test, business.industry, Ultrasound, Graft Occlusion, Vascular, Magnetic resonance imaging, Middle Aged, Peripheral, Treatment Outcome, Lower Extremity, Female, Radiology, Artifacts, Cardiology and Cardiovascular Medicine, business, Nuclear medicine, Vascular Surgical Procedures, Magnetic Resonance Angiography, Vein bypass, Boston, Lumen (unit)
Abstract

The purpose of this study is to primarily evaluate the lumen area and secondarily evaluate wall area measurements of in vivo lower extremity peripheral vein bypass grafts patients using high spatial resolution, limited field of view, cardiac gated, black blood inner volume three-dimensional fast spin echo MRI. Fifteen LE-PVBG patients prospectively underwent ultrasound followed by T1-weighted and T2-weighted magnetic resonance (MR) imaging. Lumen and vessel wall areas were measured by direct planimetry. For graft lumen areas, T1- and T2-weighted measurements were compared with ultrasound. For vessel wall areas, differences between T1- and T2-weighted measurements were evaluated. There was no significant difference between ultrasound and MR lumen measurements, reflecting minimal MR blood suppression artifact. Graft wall area measured from T1-weighted images was significantly larger than that measured from T2-weighted images (P < 0.001). The mean of the ratio of T1- versus T2-weighted vessel wall areas was 1.59 (95% CI: 1.48-1.69). The larger wall area measured on T1-weighted images was due to a significantly larger outer vessel wall boundary. Very high spatial resolution LE-PVBG vessel wall MR imaging can be performed in vivo, enabling accurate measurements of lumen and vessel wall areas and discerning differences in those measures between different tissue contrast weightings. Vessel wall area differences suggest that LE-PVBG vessel wall tissues produce distinct signal characteristics under T1 and T2 MR contrast weightings.

Published
2010

33. Regulation of PI3K signaling in T-cell acute lymphoblastic leukemia: a novel PTEN/Ikaros/miR-26b mechanism reveals a critical targetable role for PIK3CD

Author

Yuan, T, primary, Yang, Y, additional, Chen, J, additional, Li, W, additional, Zhang, Q, additional, Mi, Y, additional, Goswami, R S, additional, You, J Q, additional, Lin, D, additional, Qian, M D, additional, Calin, S, additional, Liang, Y, additional, Miranda, R N, additional, Calin, G A, additional, Zhou, X, additional, Ma, L, additional, Zweidler-McKay, P A, additional, Liu, B, additional, Weng, A P, additional, Medeiros, L J, additional, Zhang, Y, additional, and You, M J, additional

Published
2017
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