6,557 research outputs found
Comparative Biology of Temperate and Subtropical Bark and Ambrosia Beetles (Coleoptera: Scolytidae, Platypodidae) in Indiana and Florida
Bark and ambrosia beetles were compared from two intensively studied sites. The Indiana site produced 58 species, the Florida site 57 species; 17 species occurred at both sites. Much greater plant host diversity at the Indiana site seems balanced by more favorable climate at the Florida site. There are more exotic species at the Florida site. Different patterns in feeding habits and mating habits of the beetles are related to the climate and history of the sites in complex ways. A list of the and their habits is included
Cryptic species in tropic sands--interactive 3D anatomy, molecular phylogeny and evolution of meiofaunal Pseudunelidae (Gastropoda, Acochlidia)
Towards realistic estimations of the diversity of marine animals, tiny meiofaunal species usually are underrepresented. Since the biological species concept is hardly applicable on exotic and elusive animals, it is even more important to apply a morphospecies concept on the best level of information possible, using accurate and efficient methodology such as 3D modelling from histological sections. Molecular approaches such as sequence analyses may reveal further, cryptic species. This is the first case study on meiofaunal gastropods to test diversity estimations from traditional taxonomy against results from modern microanatomical methodology and molecular systematics
ARE US GASOLINE PRICE ADJUSTMENTS ASYMMETRIC?
We use the LSE-Hendry general to specific approach to analyse if US gasoline price adjustments are asymmetric with respect to changes in crude oil prices. Furthermore, we modify some weaknesses in the earlier works by Boreinstein, Cameron and Gilbert (1997) and Bachmeier and Griffin (2003) and shows that if the price adjustment equations are properly specified and estimated, alternative specifications and temporal aggregation of data do not affect the results. Monthly US data are used to show that alternative specifications give equally good results and there is no asymmetry in the US gasoline price adjustments.Asymmetric price adjustments, Market power, General to specific approach, Error correction models and Gasoline and crude oil prices
Connections on non-abelian Gerbes and their Holonomy
We introduce an axiomatic framework for the parallel transport of connections
on gerbes. It incorporates parallel transport along curves and along surfaces,
and is formulated in terms of gluing axioms and smoothness conditions. The
smoothness conditions are imposed with respect to a strict Lie 2-group, which
plays the role of a band, or structure 2-group. Upon choosing certain examples
of Lie 2-groups, our axiomatic framework reproduces in a systematical way
several known concepts of gerbes with connection: non-abelian differential
cocycles, Breen-Messing gerbes, abelian and non-abelian bundle gerbes. These
relationships convey a well-defined notion of surface holonomy from our
axiomatic framework to each of these concrete models. Till now, holonomy was
only known for abelian gerbes; our approach reproduces that known concept and
extends it to non-abelian gerbes. Several new features of surface holonomy are
exposed under its extension to non-abelian gerbes; for example, it carries an
action of the mapping class group of the surface.Comment: 57 pages. v1 is preliminary. v2 is completely rewritten, former
Sections 1 and 2 have been moved into a separate paper (arxiv:1303.4663), and
the discussion of non-abelian surface holonomy has been improved and
extended. v3 is the final and published version with a few minor correction
Evolution and loss of long-fringed petals
Background: The Cucurbitaceae genus Trichosanthes comprises 90–100 species that occur from India to Japan and southeast to Australia and Fiji. Most species have large white or pale yellow petals with conspicuously fringed margins, the fringes sometimes several cm long. Pollination is usually by hawkmoths. Previous molecular data for a small number of species suggested that a monophyletic Trichosanthes might include the Asian genera Gymnopetalum (four species, lacking long petal fringes) and Hodgsonia (two species with petals fringed). Here we test these groups’ relationships using a species sampling of c. 60% and 4759 nucleotides of nuclear and plastid DNA. To infer the time and direction of the geographic expansion of the Trichosanthes clade we employ molecular clock dating and statistical biogeographic reconstruction, and we also address the gain or loss of petal fringes.
Results: Trichosanthes is monophyletic as long as it includes Gymnopetalum, which itself is polyphyletic. The closest relative of Trichosanthes appears to be the sponge gourds, Luffa, while Hodgsonia is more distantly related. Of six morphology-based sections in Trichosanthes with more than one species, three are supported by the molecular results; two new sections appear warranted. Molecular dating and biogeographic analyses suggest an Oligocene origin of Trichosanthes in Eurasia or East Asia, followed by diversification and spread throughout the Malesian biogeographic region and into the Australian continent.
Conclusions: Long-fringed corollas evolved independently in Hodgsonia and Trichosanthes, followed by two losses in the latter coincident with shifts to other pollinators but not with long-distance ispersal events. Together with the Caribbean Linnaeosicyos, the Madagascan Ampelosicyos and the tropical African Telfairia, these cucurbit lineages represent an ideal system for more detailed studies of the evolution and function of petal fringes in plant-pollinator mutualisms
The BG News February 7, 1984
The BGSU campus student newspaper February 7, 1984. Volume 66 - Issue 70https://scholarworks.bgsu.edu/bg-news/5216/thumbnail.jp
A novel physiological role for ARF1 in the formation of bidirectional tubules from the Golgi.
Capitalizing on CRISPR/Cas9 gene-editing techniques and super-resolution nanoscopy, we explore the role of the small GTPase ARF1 in mediating transport steps at the Golgi. Besides its well-established role in generating COPI vesicles, we find that ARF1 is also involved in the formation of long (∼3 µm), thin (∼110 nm diameter) tubular carriers. The anterograde and retrograde tubular carriers are both largely free of the classical Golgi coat proteins coatomer (COPI) and clathrin. Instead, they contain ARF1 along their entire length at a density estimated to be in the range of close packing. Experiments using a mutant form of ARF1 affecting GTP hydrolysis suggest that ARF1[GTP] is functionally required for the tubules to form. Dynamic confocal and stimulated emission depletion imaging shows that ARF1-rich tubular compartments fall into two distinct classes containing 1) anterograde cargoes and clathrin clusters or 2) retrograde cargoes and coatomer clusters
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Simple method for sub-diffraction resolution imaging of cellular structures on standard confocal microscopes by three-photon absorption of quantum dots
This study describes a simple technique that improves a recently developed 3D sub-diffraction imaging method based on three-photon absorption of commercially available quantum dots. The method combines imaging of biological samples via tri-exciton generation in quantum dots with deconvolution and spectral multiplexing, resulting in a novel approach for multi-color imaging of even thick biological samples at a 1.4 to 1.9-fold better spatial resolution. This approach is realized on a conventional confocal microscope equipped with standard continuous-wave lasers. We demonstrate the potential of multi-color tri-exciton imaging of quantum dots combined with deconvolution on viral vesicles in lentivirally transduced cells as well as intermediate filaments in three-dimensional clusters of mouse-derived neural stem cells (neurospheres) and dense microtubuli arrays in myotubes formed by stacks of differentiated C2C12 myoblasts
The BG News January 14, 1986
The BGSU campus student newspaper January 14, 1986. Volume 68 - Issue 62https://scholarworks.bgsu.edu/bg-news/5467/thumbnail.jp
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