990 research outputs found
John W. Creswell, Research Design: Qualitative, Quantitative, and Mixed Methods Approaches
Abstract. John W. Creswell was previously a professor in educational psychology in the University of Nebraska–Lincoln. He moved to the University of Michigan in 2015 as a professor in the Department of Family Medicine. He has published many articles and close to 27 books on mixed methods. Professor Creswell is also one of the founding members of the Journal of Mixed Methods Research. He was a Fulbright scholar in South Africa in 2008 and Thailand in 2012. In 2011, he served as a visiting professor in the School of Public Health of Harvard University. In 2014, he became the Chairman of the Mixed Methods International Research Association. Professor Creswell has a personal website called “Mixed Methods Research” at http://johnwcreswell.com/. The site contains the information about his background, his own blog, consulting works and published books. He also posted replies questions from academic researchers and practitioners in the blog.Keywords. Research design, Methodology, Methods.JEL. A20, B40, B49
Application of satellite cloud brightness data for large-scale tropical analysis: A correlation study of brightness and 200-mb divergence
This is a preliminary analysis of digitized satellite cloud brightness
data that will be used in developing a model for large-scale analysis over
data-void tropical areas, which is based on Wallace's (1971) postulation
that such data may be used to estimate vertical motion in the tropics. The relationship between satellite cloud brightness and large-scale
200 mb divergence on 5° x 5° grids in the tropical western North Pacific is examined from several angles. Correlation coefficients between the two
fields are computed on a daily basis for the region of study and at each
grid point for 8-month time series. The coefficients are mostly low
although a positive correlation is generally indicated. The low correlation
may be due to the quality of the available data, especially for
the divergence which is kinematically computed from analyzed winds.
Spectrum analysis is also performed to determine dominant synoptic time
scales for both parameters in the period of study. Two common period
bands, one centered ~ 10 days and the other ^ 5 days, are found. Crossspectra
between the two parameters indicate that their phase differences
are small (< 1/4 cycle) for both bands, but the coherence squares are
somewhat lower than those found previously by Wallace for the 4- to 5-
day waves using direct radiosonde data. Horizontal structures of both
parameters, determined from inter-longitude cross-spectra in the two
bands, suggest that the brightness is much more organized than divergence,
but the two fields resemble each other whenever an organized
pattern in divergence can be found. The results of this study lend some support to Wallace's postulation,
but also indicate some problems for using the present data. It
is anticipated that the correspondence with the actual divergence field
will be greatly improved if satellite infrared data is incorporated
into the brightness data.supported by the National Environmental
Satellite Service, National Oceanic and Atmospheric Administration, under
contract NA-833-73.http://archive.org/details/applicationofsat00chanNA 883-73N
Association between chronic viral hepatitis infection and breast cancer risk: a nationwide population-based case-control study
<p>Abstract</p> <p>Background</p> <p>In Taiwan, there is a high incidence of breast cancer and a high prevalence of viral hepatitis. In this case-control study, we used a population-based insurance dataset to evaluate whether breast cancer in women is associated with chronic viral hepatitis infection.</p> <p>Methods</p> <p>From the claims data, we identified 1,958 patients with newly diagnosed breast cancer during the period 2000-2008. A randomly selected, age-matched cohort of 7,832 subjects without cancer was selected for comparison. Multivariable logistic regression models were constructed to calculate odds ratios of breast cancer associated with viral hepatitis after adjustment for age, residential area, occupation, urbanization, and income. The age-specific (<50 years and ≥50 years) risk of breast cancer was also evaluated.</p> <p>Results</p> <p>There were no significant differences in the prevalence of hepatitis C virus (HCV) infection, hepatitis B virus (HBV), or the prevalence of combined HBC/HBV infection between breast cancer patients and control subjects (<it>p </it>= 0.48). Multivariable logistic regression analysis, however, revealed that age <50 years was associated with a 2-fold greater risk of developing breast cancer (OR = 2.03, 95% CI = 1.23-3.34).</p> <p>Conclusions</p> <p>HCV infection, but not HBV infection, appears to be associated with early onset risk of breast cancer in areas endemic for HCV and HBV. This finding needs to be replicated in further studies.</p
A Novel Family of Cyst Proteins with Epidermal Growth Factor Repeats in Giardia lamblia
The biological goal of Giardia lamblia life cycle is differentiation into a cyst form (encystation) that can survive in the environment and infect a new host. Since cystic stages are key to transmission of parasites, this differentiation may be a target for interruption of the life cycle. Synthesis and assembly of the extracellular cyst wall are the major hallmarks of this important differentiation. During encystation, cyst wall structural proteins are coordinately synthesized and are mainly targeted to the cyst wall. However, only a few such proteins have been identified to date. In this study, we used a combination of bioinformatics and molecular approaches to identify new cyst structural proteins from G. lamblia and found a group of Epidermal Growth Factor (EGF)-like Repeats containing Cyst Proteins (EGFCPs). Interestingly, the levels of EGFCPs proteins increased significantly during encystation, which matches the characteristics of the Giardia cyst wall protein. Further characterization and localization studies suggest that EGFCPs may function like cyst wall proteins, involved in differentiation of G. lamblia trophozoites into cysts. Our results provide valuable information regarding the function of a new group of cyst proteins in parasite differentiation into cysts and help develop ways to interrupt the parasite life cycle
catena-Poly[[tetraaquanickel(II)]-μ3-benzene-1,3,5-tricarboxylato-3′:1:2-κ4 O 1:O 3,O 3′:O 5-[tetraaquanickel(II)]-μ2-benzene-1,3,5-tricarboxylato-2:3κ2 O 1:O 3-[tetraaquanickel(II)]]
The microwave solvothermal reaction of nickel nitrate with trimesic acid provided the title compound, [Ni3(BTC)2(H2O)12]n (BTC = benzene-1,3,5-tricarboxylÂate anion, C9H3O6), which is a metal coordination polymer composed of one-dimensional zigzag chains. The crystal under investigation was ramecically twinned with an approximate twin domain ratio of 1:1. In the asymmetric unit, there are two types of Ni atoms. One of the NiO6 groups (2 symmetry) is coordinated to only one carboxylÂate group and thus terminal, the other is bridging, forming the coordination polymer. The extended chains are connected by the organic BTC anions via ÎĽ
2-linkages. O—Hâ‹ŻO hydrogen bonds and π–π interÂactions between the chains [centroid–centroid distance 3.58 (1) Å] induce the complex to mimic a three-dimensional structure
Understanding Multidecadal Climate Changes
The 2012 National Taiwan University International Science Conference on Climate Change focused on two of the most difficult challenges in the study of climate change. The 23 invited reviews at the conference were presented in hour-long segments, each beginning with a lecture and followed by discussion. These reviews were augmented by 20 contributed oral and poster papers. The AMOC fingerprints described at the meeting may be used for reconstructing AMOC variations in the past and monitoring AMOC variations in the future. Modeling studies indicate that the AMOC weakens most at northern high latitudes in response to increasing greenhouse gas concentrations. The number, intensity, tracks, and landfall locations of WNP TCs also exhibit strong decadal or multidecadal variations. When adjusted for likely missed TCs, the observational record does not show evidence of a significant secular trend in North Atlantic hurricane activity
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