Michael Rex - Academia.edu (original) (raw)

Papers by Michael Rex

Energies

Hydrogen fuel cell vehicles can complement other electric vehicle technologies as a zero-emission... more Hydrogen fuel cell vehicles can complement other electric vehicle technologies as a zero-emission technology and contribute to global efforts to achieve the emission reduction targets. This article spotlights the current deployment status of fuel cells in road transport. For this purpose, data collection was performed by the Advanced Fuel Cells Technology Collaboration Programme. Moreover, the available incentives for purchasing a fuel cell vehicle in different countries were reviewed and future perspectives summarized. Based on the collected information, the development trends in the last five years were analyzed and possible further trends that could see the realization of the defined goals derived. The number of registered vehicles was estimated to be 51,437 units, with South Korea leading the market, with 90% of the vehicles being concentrated in four countries. A total of 729 hydrogen refueling stations were in operation, with Japan having the highest number of these. The analy...

This dataset includes counts of Protobranch bivalves collected in a series of epibenthic sled sam... more This dataset includes counts of Protobranch bivalves collected in a series of epibenthic sled samples taken on R/V Endeavor cruise EN447 in the Western North Atlantic (34-39N, 68-70W) in 2008.

Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag, 2021

The number of fuel cell‐powered vehicles being used for road transport is rapidly increasingaroun... more The number of fuel cell‐powered vehicles being used for road transport is rapidly increasingaround the world. In order to determine their present deployment status, the InternationalEnergy Agency (IEA) Advanced Fuel Cells Technology Collaboration Programme (AFC TCP) performsan annual data collection across its member countries and beyond. This report capturesthe current state of the country‐base deployment of fuel cell vehicles globally as of the end of2020. Furthermore, an overview of the worldwide hydrogen refueling station infrastructure ispresented. Based on the most recent numbers and those from more recent years, the developmenttrends are analyzed. Furthermore, information on selected passenger vehicles operatingwith fuel cell technology is updated and accompanied by an analysis of different incentivesand vehicle prices in various countries. Apart from the number of hydrogen refuelingstations, available information on the stations, such as pressure levels and links to their locations,are presented. Finally, the report reviews the defined targets, projections and visionsregarding the future development perspectives of fuel cell vehicles and hydrogen refuelingstations.Based on the results of the data collection, the AFC TCP estimates a total of 34,804 fuel cellvehicles and 540 hydrogen refueling stations to be in operation as of the end of 2020. Thetotal number of fuel cell vehicles is made up of 25,932 passenger cars, which saw a 37% increasein 2020. Having undergone a strong increase in a single year, South Korea now has themajority of passenger cars equipped with fuel cell technology on its roads. China still leadsglobal markets for buses and medium‐duty trucks. Moreover, the public refueling stations inJapan, Germany, China, and the U.S. represent a significant share of 63% of the total numberof stations worldwide

The purpose of this quasi-experimental study was to examine the impact of a selfassessment questi... more The purpose of this quasi-experimental study was to examine the impact of a selfassessment questionnaire of behavior on the science achievement of students in a general education high school class. The study compared the percent correct on a unit vocabulary assessment of 43 high school students varying from ninth to eleventh grade that received a traditional warm-up/closure lesson design and 44 high school students varying from ninth to eleventh grade that received the lesson design with an added self-assessment questionnaire. For seven class periods, spanning approximately three weeks, the questionnaire was implemented to the 44 students. The questionnaire had students analyzing their behaviors throughout the lesson and was provided at the end of each lesson. After taking the vocabulary assessment, the mean percent correct of the control group (mean = 77.78, SD = 24.40) did not differ statistically different from the mean percent correct of the experimental group (mean = 84.73, SD = 16.21) [t(85) = 1.57, p = .120 ]. The results of the study failed to reject the null hypothesis, however the study had significant alterations due to the COVID-19 pandemic occurring approximately halfway through the study. The study suggested possible benefits to increasing student motivation and engagement. The exploration of the relationship between motivational techniques and academic achievement is essential to further the improvement of student success.

Deep Sea Research and Oceanographic Abstracts, 1976

AImtnmt-Measures of the diversity and relative abundance of gastropod predators are positively an... more AImtnmt-Measures of the diversity and relative abundance of gastropod predators are positively and significantly correlated with overall gastropod diversity in 15 epibenthic sled samples collected from 478 to 4862 m along the Gay Head-Bermuda transect. Predator diversity is lowest on the abyssal plain, highest on the lower continental slope and abyssal rise, and relatively low on the upper continental slope. The variation of gastropod predator diversity with depth is similar to those of their most probable prey, the polychaetes and protobranch bivalves. Predator diversity and overall diversity were also related to variation in faunal density with depth. Density decreases exponentially with depth and reflects the average rate of production reaching the deep-sea benthos. Relationships among diversity, predation, and production are consistent with the theory that predators exert a diversifying influence on communities and that the degree to which they are able to do this depends on the rate and stability of production. The results suggest that both predation and productivity are important to biological accommodation in deep-sea communities and that their relative contributions to maintaining diversity vary considerably with depth.

Annual Review of Ecology, Evolution, and Systematics, 2015

We review patterns and causes of β-diversity in the deep-sea benthos at different spatial scales ... more We review patterns and causes of β-diversity in the deep-sea benthos at different spatial scales and for different body sizes. Changes in species composition occurring with depth are generally gradual, the rate of change being a function of the rate of descent. This gradual change can be interrupted by abrupt environmental shifts, such as oxygen minimum zones, and by major topographic features that alter oceanographic conditions. Changes in species composition with depth can involve both species replacement and species loss, leading to nestedness. Horizontal β-diversity is more moderate than that occurring with depth, except at upper bathyal zones impacted by coastal influences. At very large oceanic scales, both environmental filtering and dispersal limitation influence β-diversity. Although many ecological and evolutionary–historical factors must shape β-diversity in the deep sea, energy availability appears to structure community makeup at all scales examined. We recommend that s...

Due to the character of the original source materials and the nature of batch digitization, quali... more Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references.This thesis deals with the poetry of Anne Killigrew. It also discusses her literary reputation, both historical and current. Killigrew poetry is examined in four different areas, showing her experiments in genre, form, and voice. pessimistic poetry. This thesis also shows how Killigrew used the literary conventions of her period. The argument is based both on new historicism and close readings of the individual poems. The literary milieu is established by discussions of both traditional literary interpretation, specifically those of John Dryden, and the act of manuscript circulation

Because of the scholarly concentration on the novel, eighteenth-century women epic poets have bee... more Because of the scholarly concentration on the novel, eighteenth-century women epic poets have been ignored. The question of English women writing epic poetry has never been seriously treated before, at least in part because of the assumption that women were incapable of writing in this genre, or that the English culture of the eighteenth century itself rejected epic poetry. Using

Science, 1973

Gastropod species diversity is low on the continental shelf, high on the continental slope and ab... more Gastropod species diversity is low on the continental shelf, high on the continental slope and abyssal rise, and then decreases with increasing distance out onto the abyssal plain. Increased diversity below the continental shelf has been attributed to increased environmental stability. Decreased diversity on the abyss may result from extremely low productivity.

Nature, 1997

Organisms at the bottom of the deep seas might seem to be immune from large-scale shifts in clima... more Organisms at the bottom of the deep seas might seem to be immune from large-scale shifts in climate. Not so, according to a study which reveals links between benthic biodiversity, glaciation and the Earth's obliquity.

Marine Ecology, 2009

Bathymetric patterns of deep-sea species diversity have emerged as a class of large-scale biogeog... more Bathymetric patterns of deep-sea species diversity have emerged as a class of large-scale biogeographic trends

Evolution, 2005

The deep sea is the largest ecosystem on Earth. Recent exploration has revealed that it supports ... more The deep sea is the largest ecosystem on Earth. Recent exploration has revealed that it supports a highly diverse and endemic benthic invertebrate fauna, yet the evolutionary processes that generate this remarkable species richness are virtually unknown. Environmental heterogeneity, topographic complexity, and morphological divergence all tend to decrease with depth, suggesting that the potential for population differentiation may decrease with depth. To test this hypothesis, we use mitochondrial DNA (16S rRNA gene) to examine patterns of population differentiation in four species of protobranch bivalves (Nuculoma similis, Deminucula atacellana, Malletia abyssorum, and Ledella ultima) distributed along a depth gradient in the western North Atlantic. We sequenced 268 individuals from formalinfixed samples and found 45 haplotypes. The level of sequence divergence among haplotypes within species was similar, but shifted from between populations at bathyal depths to within populations at abyssal depths. Levels of population structure as measured by ⌽ ST were considerably greater in the upper bathyal species (N. similis ϭ 0.755 and D. atacellana ϭ 0.931; 530-3834 m) than in the lower bathyal/abyssal species (M. abyssorum ϭ 0.071 and L. ultima ϭ 0.045; 2864-4970 m). Pairwise genetic distances among the samples within each species also decreased with depth. Population trees (UPGMA) based on modified coancestry coefficients and nested clade analysis both indicated strong population-level divergence in the two upper bathyal species but little for the deeper species. The population genetic structure in these protobranch bivalves parallels depth-related morphological divergence observed in deep-sea gastropods. The higher level of genetic and morphological divergence, coupled with the strong biotic and abiotic heterogeneity at bathyal depths, suggests this region may be an active area of species formation. We suggest that the steep, topographically complex, and dynamic bathyal zone, which stretches as a narrow band along continental margins, plays a more important role in the evolutionary radiation of the deep-sea fauna than the much more extensive abyss.

Evolution, 2004

Studies of deep-sea biodiversity focus almost exclusively on geographic patterns of ␣-diversity. ... more Studies of deep-sea biodiversity focus almost exclusively on geographic patterns of ␣-diversity. Few include the morphological or ecological properties of species that indicate their actual roles in community assembly. Here, we explore morphological disparity of shell architecture in gastropods from lower bathyal and abyssal environments of the western North Atlantic as a new dimension of deep-sea biodiversity. The lower bathyal-abyssal transition parallels a gradient of decreasing species diversity with depth and distance from land. Morphological disparity measures how the variety of body plans in a taxon fills a morphospace. We examine disparity in shell form by constructing both empirical (eigenshape analysis) and theoretical (Schindel's modification of Raup's model) morphospaces. The two approaches provide very consistent results. The centroids of lower bathyal and abyssal morphospaces are statistically indistinguishable. The absolute volumes of lower bathyal morphospaces exceed those of the abyss; however, when the volumes are standardized to a common number of species they are not significantly different. The abyssal morphospaces are simply more sparsely occupied. In terms of the variety of basic shell types, abyssal species show the same disparity values as random subsets of the lower bathyal fauna. Abyssal species possess no evident evolutionary innovation. There are, however, conspicuous changes in the relative abundance of shell forms between the two assemblages. The lower bathyal fauna contains a fairly equable mix of species abundances, trophic modes, and shell types. The abyssal group is numerically dominated by species that are deposit feeders with compact unsculptured shells.

Ecology, 2005

Large-scale biogeographic patterns in marine systems are considerably less well documented and un... more Large-scale biogeographic patterns in marine systems are considerably less well documented and understood than those in terrestrial systems. Here, we synthesize recent evidence on latitudinal and bathymetric gradients of species diversity in benthic mollusks, one of the most diverse and intensively studied marine taxa. Latitudinal gradients in coastal faunas show poleward declines in diversity, but the patterns are highly asymmetrical between hemispheres, and irregular both within and among regions. The extensive fossil record of mollusks reveals that latitudinal gradients have become steeper during the Neogene, partly because of a rapid diversification in tropical coral reefs and their associated biotas. Much of the interregional variation in contemporary latitudinal trends depends on the longitudinal distribution of reefs and major Neogene vicariant events. Thus, coastal faunas reveal a strong evolutionary-historical legacy. Bathymetric and latitudinal gradients in the deep ocean suggest that molluscan diversity is a function of the rate of nutrient input from surface production. Diversity may be depressed at abyssal depths because of extremely low rates of organic carbon flux, and at upper bathyal depths and high latitudes by pulsed nutrient loading. While the deep-sea environment is not conducive to fossilization, relationships between local and regional diversity, and the distribution and age of higher taxa indicate an evolutionary signal in present-day diversity gradients. Marine invertebrate communities offer tremendous potential to determine the relative importance of history and ecological opportunity in shaping large-scale patterns of species diversity.

Deep Sea Research Part II: Topical Studies in Oceanography, 1998

The evolution of body size is a problem of fundamental interest, and one that has an important be... more The evolution of body size is a problem of fundamental interest, and one that has an important bearing on community structure and conservation of biodiversity. The most obvious and pervasive characteristic of the deep-sea benthos is the small size of most species. The numerous attempts to document and explain geographic patterns of body size in the deep-sea benthos have focused on variation among species or whole faunal components, and have led to conflicting and contradictory results. It is important to recognize that studying size as an adaptation to the deep-sea environment should include analyses within species using measures of size that are standardized to common growth stages. An analysis within eight species of deep-sea benthic gastropods presented here reveals a clear trend for size to increase with depth in both larval and adult shells. An ANCOVA with multiple comparison tests showed that, in general, size-depth relationships for both adult and larval shells are more pronounced in the bathyal region than in the abyss. This result reinforces the notion that steepness of the bathymetric selective gradient decreases with depth, and that the bathyal region is an evolutionary hotspot that promotes diversification. Bathymetric size clines in gastropods support neither the predictions of optimality models nor earlier arguments based on tradeoffs among scaling factors. As in other environments, body size is inversely related to both abundance and species density. We suggest that the decrease in nutrient input with depth may select for larger size because of its metabolic or competitive advantages, and that larger size plays a role in limiting diversity. Adaptation is an important evolutionary driving force of biological diversity, and geographic patterns of body size could help unify ecological and historical theories of deep-sea biodiversity.

Deep Sea Research Part I: Oceanographic Research Papers, 1999

Our knowledge of deep-sea biodiversity is based almost entirely on morphological distinctions at ... more Our knowledge of deep-sea biodiversity is based almost entirely on morphological distinctions at the species level. Here, we use haplotype variations in the mitochondrial 16S ribosomal gene to assess biodiversity at the genome level in four deep-sea molluscan morphospecies. Genetic divergence levels among populations of the morphospecies fall within the range of interspeci"c divergence found in coastal marine and aquatic molluscan genera. Results indicate a rich population structure at the genetic level in deep-sea mollusks, and suggest the possibility that some seemingly coherent morphospecies are composed of cryptic species. 1999 Elsevier Science Ltd. All rights reserved.