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Institution

University of Maryland, Baltimore County

EducationBaltimore, Maryland, United States
About: University of Maryland, Baltimore County is a education organization based out in Baltimore, Maryland, United States. It is known for research contribution in the topics: Population & Aerosol. The organization has 8749 authors who have published 20843 publications receiving 795706 citations. The organization is also known as: UMBC.


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Journal ArticleDOI
TL;DR: The maximal procedure takes as input the extent of chronological bias allowed by the randomized block procedure, then matches it, but does so with fewer restrictions, which makes the maximal procedure more resistant to selection bias than the randomizedBlock procedure is.
Abstract: The interpretation of between-group comparisons is facilitated by the creation of treatment groups that are similar to each other in baseline composition. To prevent treatment effects from being confounded with time effects, most trials use restricted randomization to force balance. An unintended consequence of these restrictions is that they create patterns that allow for the prediction of future treatment allocations, and hence selection bias, especially in unmasked trials. In fact, the more restrictive the allocation procedure, the greater the potential for selection bias. It was decided, in the context of a recent clinical trial comparing two dosing schedules of paclitaxel and carboplatin for advanced stage IIIB/IV non-small-cell lung cancer, that the randomized block procedure could not simultaneously protect sufficiently against both selection and chronological bias. In this paper we detail our development of the maximal procedure. The maximal procedure takes as input the extent of chronological bias allowed by the randomized block procedure, then matches it, but does so with fewer restrictions. This feature makes the maximal procedure more resistant to selection bias than the randomized block procedure is.

170 citations

Journal ArticleDOI
TL;DR: Redundant bands identified in this study will help overcome the Hughes Phenomenon in hyperspectral data for a particular application (e.g., biophysical characterization of crops) and make a significant contribution to future hyperspectrals such as NASA's HyspIRI.
Abstract: The overarching goal of this study was to establish optimal hyperspectral vegetation indices (HVIs) and hyperspectral narrowbands (HNBs) that best characterize, classify, model, and map the world's main agricultural crops. The primary objectives were: (1) crop biophysical modeling through HNBs and HVIs, (2) accuracy assessment of crop type discrimination using Wilks' Lambda through a discriminant model, and (3) meta-analysis to select optimal HNBs and HVIs for applications related to agriculture. The study was conducted using two Earth Observing One (EO-1) Hyperion scenes and other surface hyperspectral data for the eight leading worldwide crops (wheat, corn, rice, barley, soybeans, pulses, cotton, and alfalfa) that occupy ~70% of all cropland areas globally. This study integrated data collected from multiple study areas in various agroecosystems of Africa, the Middle East, Central Asia, and India. Data were collected for the eight crop types in six distinct growth stages. These included (a) field spectroradiometer measurements (350-2500 nm) sampled at 1-nm discrete bandwidths, and (b) field biophysical variables (e.g., biomass, leaf area index) acquired to correspond with spectroradiometer measurements. The eight crops were described and classified using ~20 HNBs. The accuracy of classifying these 8 crops using HNBs was around 95%, which was ~ 25% better than the multi-spectral results possible from Landsat-7's Enhanced Thematic Mapper+ or EO-1's Advanced Land Imager. Further, based on this research and meta-analysis involving over 100 papers, the study established 33 optimal HNBs and an equal number of specific two-band normalized difference HVIs to best model and study specific biophysical and biochemical quantities of major agricultural crops of the world. Redundant bands identified in this study will help overcome the Hughes Phenomenon (or “the curse of high dimensionality”) in hyperspectral data for a particular application (e.g., biophysical characterization of crops). The findings of this study will make a significant contribution to future hyperspectral missions such as NASA's HyspIRI.

170 citations

Journal ArticleDOI
TL;DR: A method has been developed that combines electrospray ionization mass spectrometry with pH control to provide analysis of metals in native or reconstituted metallothioneins, and the retention of seven metals in the molecular ions detected is consistent with the hypothesis that metallothsionein retains its conformation in the gas phase.
Abstract: A method has been developed that combines electrospray ionization mass spectrometry with pH control to provide analysis of metals in native or reconstituted metallothioneins. These metalloproteins cooperatively bind seven divalent metal ions, most commonly Zn2+ and Cd2+. Since the protein is denatured and metal ions are lost below pH3, the pH of the electrospray solution is critical to successful results. The metal-free apoprotein was detected with its most abundant ions in a charge state of 6+, while the folded metallothionein-metal complexes were observed with lower charge states. The retention of seven metals in the molecular ions detected is consistent with the hypothesis that metallothionein retains its conformation in the gas phase. This mass spectrometric technique can be used to determine rapidly and accurately how many and what cations are incorporated per molecule of protein. Information about molar distributions and estimates of relative abundances of various complexes in the sample can be acquired in a single measurement.

170 citations

Posted Content
TL;DR: The results show that the national culture of group minorities has a significant impact on majority influence and that the use of computer-mediated communication can reduce majority influence.
Abstract: Majority influence is the attempt by a majority of group members to impose their common position on group dissenters during group decision making. Because of globalization, the use of cross-cultural teams in group tasks is becoming increasingly common. The objective of this study was to investigate how national culture, social presence, and group diversity may affect majority influence in a group decision-making context. A total of 183 groups participated in a large-scale empirical experiment at multiple sites. The results show that the national culture of group minorities has significant impact on majority influence and that the use of computer-mediated communication can reduce majority influence. The findings have both theoretical and practical implications for improving the outcome and the effectiveness of group decision making in cross-cultural environments.

170 citations

Journal ArticleDOI
TL;DR: Issues with current standard satellite retrievals are summarized, new ideas to use additional information from existing and upcoming spaceborne instruments are discussed, and approaches using high‐quality ground‐based observations are examined.
Abstract: The cloud droplet number concentration (Nd) is of central interest to improve the understanding of cloud physics and for quantifying the effective radiative forcing by aerosol-cloud interactions. Current standard satellite retrievals do not operationally provide Nd, but it can be inferred from retrievals of cloud optical depth (τc) cloud droplet effective radius (re) and cloud top temperature. This review summarizes issues with this approach and quantifies uncertainties. A total relative uncertainty of 78% is inferred for pixel-level retrievals for relatively homogeneous, optically thick and unobscured stratiform clouds with favorable viewing geometry. The uncertainty is even greater if these conditions are not met. For averages over 1° ×1° regions the uncertainty is reduced to 54% assuming random errors for instrument uncertainties. In contrast, the few evaluation studies against reference in situ observations suggest much better accuracy with little variability in the bias. More such studies are required for a better error characterization. Nd uncertainty is dominated by errors in re, and therefore, improvements in re retrievals would greatly improve the quality of the Nd retrievals. Recommendations are made for how this might be achieved. Some existing Nd data sets are compared and discussed, and best practices for the use of Nd data from current passive instruments (e.g., filtering criteria) are recommended. Emerging alternative Nd estimates are also considered. First, new ideas to use additional information from existing and upcoming spaceborne instruments are discussed, and second, approaches using high-quality ground-based observations are examined.

169 citations


Authors

Showing all 8862 results

NameH-indexPapersCitations
Robert C. Gallo14582568212
Paul T. Costa13340688454
Igor V. Moskalenko13254258182
James Chiang12930860268
Alex K.-Y. Jen12892161811
Alan R. Shuldiner12055771737
Richard N. Zare120120167880
Vince D. Calhoun117123462205
Rita R. Colwell11578155229
Kendall N. Houk11299754877
Elliot K. Fishman112133549298
Yoram J. Kaufman11126359238
Paulo Artaxo10745444346
Braxton D. Mitchell10255849599
Sushil Jajodia10166435556
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
202371
2022165
20211,065
20201,091
2019989
2018929