6,616 research outputs found
WHAT CAN SCARABAEOIDEA CONTRIBUTE TO THE KNOWLEDGE OF THE BIOGEOGRAPHY OF GUATEMALA?
Scarabaeoidea is one of the biogeographically best known groups of organisms for Nuclear Central America, especially Guatemala. They have been used to determine areas of endemism for cloud forests of the region and to analyze relationships among these endemic areas. A major north-south division of these areas is described. Lowland scenarios are also given. This information was used for justifying the establishment of biological reserves in the area and is a tool available for prioritization of reserve establishment that could be adapted to other parts of the world as well.
Scarabaeoidea es uno de los grupos mejor conocidos biogeograficamente en Centroamerica Nuclear, especialmente Guatemala. Han sido usados para establecer areas de endemismo en bosques nubosos de la region y para analizar relaciones entre esas areas. Una division mayor norte-sur de estas areas endemicas esta descrita. Escenarios de tierra de baja elevaci6n tambien se presentan. Esta informacion fue usada para justificar el establecimiento de reservas biologicas en el area y como una valiosa herramienta para priorizar el establecimiento de reservas, lo cual podria ser adaptado tambien a otras partes del mundo
A NEW SPECIES OF \u3ci\u3ePETREJOIDES\u3c/i\u3e FROM GUATEMALA AND COMMENTS ON \u3ci\u3ePETREJOIDES MICHOACANAE\u3c/i\u3e(COLEOPTERA: PASSALIDAE)
Petrejoides caralae New Species is described from wet lowland forest of eastern Guatemala (450-950 m altitude). The aedeagus of Petrejoides michoacanae Schuster is described.
Se describe Petrejoides caralae Nueva Especie de bosque hiimedo de tierras ba- jas, del este de Guatemala, entre 450-950 metros de altitud. Se describe el edeago de Petrejoides michoacanae Schuster
OGYGES AND VETURIUS (COLEOPTERA: PASSALIDAE) IN CENTRAL AMERICA: SYNONYMIES, RANGE EXTENSIONS AND NEW SPECIES
The following nomenclatural changes in passalid taxonomy are made: Veturius laevior (Kaup 1868) n.stat., bona sp.; V. lineatosulcatus Luederwaldt 1941, n. syn. of V. laevior; Ogyges championi (Bates 1886) n. stat., bona sp.; and O. laevior (Kaup 1868) sensu auct., n. syn.of O. championi. New distribution records are given for V. sinuatocollis Kuwert 1890 (Honduras), O. crassulus (Casey) (Guatemala, Honduras), O. championi, O. cakchiqueli Schuster & Reyes-Castillo 1990, O. tzutuhili Schuster & Reyes-Castillo 1990, O. hondurensis Schuster & Reyes- Castillo 1990, O. quichensis Schuster & Reyes-Castillo 1990 and O. politus (Hincks 1953) (Guatemala). O. crassulus is redescribed and O. coxchicopi n. sp., O. monzoni n. sp., O. aluxi n. sp. and O. nahuali n. sp. are described, all species from cloud forests between 900 and 2064m altitude in Guatemala and Honduras. A key to the species of Ogyges is given.Se realizaron los siguientes cambios nomenclatoriales en la taxonomía de Passalidae: Veturius laevior (Kaup 1868) n.stat., bona sp.; V. lineatosulcatus Luederwaldt 1941, n. syn. de V. laevior; Ogyges championi (Bates 1886) n. stat., bona sp.; y O. laevior (Kaup 1868) sensu auct., n. syn.de O. championi. Se presentan nuevos registros de distribución de V. sinuatocollis Kuwert 1890 (Honduras), O. crassulus (Casey) (Guatemala, Honduras), O. championi, O. cakchiqueli Schuster & Reyes-Castillo 1990, O. tzutuhili Schuster & Reyes-Castillo 1990, O. hondurensis Schuster & Reyes-Castillo 1990, O. quichensis Schuster & Reyes-Castillo 1990 y O. politus (Hincks 1953) (Guatemala). Se redescribe O. crassulus y se describen O. coxchicopi n. sp., O. monzoni n. sp., O. aluxi n .sp. y O. nahuali n. sp., todas especies de bosques nubosos o mesófilos de montaña, entre 900 y 2064msnm de Guatemala y Honduras. Se presenta una clave para las especies de Ogyges
Graph Theory Data for Topological Quantum Chemistry
Topological phases of noninteracting particles are distinguished by global
properties of their band structure and eigenfunctions in momentum space. On the
other hand, group theory as conventionally applied to solid-state physics
focuses only on properties which are local (at high symmetry points, lines, and
planes) in the Brillouin zone. To bridge this gap, we have previously [B.
Bradlyn et al., Nature 547, 298--305 (2017)] mapped the problem of constructing
global band structures out of local data to a graph construction problem. In
this paper, we provide the explicit data and formulate the necessary algorithms
to produce all topologically distinct graphs. Furthermore, we show how to apply
these algorithms to certain "elementary" band structures highlighted in the
aforementioned reference, and so identified and tabulated all orbital types and
lattices that can give rise to topologically disconnected band structures.
Finally, we show how to use the newly developed BANDREP program on the Bilbao
Crystallographic Server to access the results of our computation.Comment: v1: 29 Pages, 13 Figures. Explains how to access the data presented
in arXiv:1703.02050 v2: Accepted version. References updated, figures
improve
Building Blocks of Topological Quantum Chemistry: Elementary Band Representations
The link between chemical orbitals described by local degrees of freedom and
band theory, which is defined in momentum space, was proposed by Zak several
decades ago for spinless systems with and without time-reversal in his theory
of "elementary" band representations. In Nature 547, 298-305 (2017), we
introduced the generalization of this theory to the experimentally relevant
situation of spin-orbit coupled systems with time-reversal symmetry and proved
that all bands that do not transform as band representations are topological.
Here, we give the full details of this construction. We prove that elementary
band representations are either connected as bands in the Brillouin zone and
are described by localized Wannier orbitals respecting the symmetries of the
lattice (including time-reversal when applicable), or, if disconnected,
describe topological insulators. We then show how to generate a band
representation from a particular Wyckoff position and determine which Wyckoff
positions generate elementary band representations for all space groups. This
theory applies to spinful and spinless systems, in all dimensions, with and
without time reversal. We introduce a homotopic notion of equivalence and show
that it results in a finer classification of topological phases than approaches
based only on the symmetry of wavefunctions at special points in the Brillouin
zone. Utilizing a mapping of the band connectivity into a graph theory problem,
which we introduced in Nature 547, 298-305 (2017), we show in companion papers
which Wyckoff positions can generate disconnected elementary band
representations, furnishing a natural avenue for a systematic materials search.Comment: 15+9 pages, 4 figures; v2: minor corrections; v3: updated references
(published version
Band Connectivity for Topological Quantum Chemistry: Band Structures As A Graph Theory Problem
The conventional theory of solids is well suited to describing band
structures locally near isolated points in momentum space, but struggles to
capture the full, global picture necessary for understanding topological
phenomena. In part of a recent paper [B. Bradlyn et al., Nature 547, 298
(2017)], we have introduced the way to overcome this difficulty by formulating
the problem of sewing together many disconnected local "k-dot-p" band
structures across the Brillouin zone in terms of graph theory. In the current
manuscript we give the details of our full theoretical construction. We show
that crystal symmetries strongly constrain the allowed connectivities of energy
bands, and we employ graph-theoretic techniques such as graph connectivity to
enumerate all the solutions to these constraints. The tools of graph theory
allow us to identify disconnected groups of bands in these solutions, and so
identify topologically distinct insulating phases.Comment: 19 pages. Companion paper to arXiv:1703.02050 and arXiv:1706.08529
v2: Accepted version, minor typos corrected and references added. Now
19+epsilon page
Topological quantum chemistry
The past decade's apparent success in predicting and experimentally
discovering distinct classes of topological insulators (TIs) and semimetals
masks a fundamental shortcoming: out of 200,000 stoichiometric compounds extant
in material databases, only several hundred of them are topologically
nontrivial. Are TIs that esoteric, or does this reflect a fundamental problem
with the current piecemeal approach to finding them? To address this, we
propose a new and complete electronic band theory that highlights the link
between topology and local chemical bonding, and combines this with the
conventional band theory of electrons. Topological Quantum Chemistry is a
description of the universal global properties of all possible band structures
and materials, comprised of a graph theoretical description of momentum space
and a dual group theoretical description in real space. We classify the
possible band structures for all 230 crystal symmetry groups that arise from
local atomic orbitals, and show which are topologically nontrivial. We show how
our topological band theory sheds new light on known TIs, and demonstrate the
power of our method to predict a plethora of new TIs.Comment: v1: 8 pages + 40 pages supplemenetary material. Previously submitted
v2: ~ Published version. 11 pages + 79 pages supplementary material.
Descriptions of the data used in this paper can be found in arXiv:1706.08529
and arXiv:1706.09272. All data can be accessed via the Bilbao
Crystallographic Server (http://cryst.ehu.es). Two additional papers
elaborating on the general theory currently in pre
Cold atoms near superconductors: Atomic spin coherence beyond the Johnson noise limit
We report on the measurement of atomic spin coherence near the surface of a
superconducting niobium wire. As compared to normal conducting metal surfaces,
the atomic spin coherence is maintained for time periods beyond the Johnson
noise limit. The result provides experimental evidence that magnetic near field
noise near the superconductor is strongly suppressed. Such long atomic spin
coherence times near superconductors open the way towards the development of
coherently coupled cold atom / solid state hybrid quantum systems with
potential applications in quantum information processing and precision force
sensing.Comment: Major revisions of the text for submission to New Journal of Physics
8 pages, 4 figure
\u3ci\u3ePROCULUS\u3c/i\u3e, GIANT LATIN-AMERICAN PASSALIDS: REVISION, PHYLOGENY AND BIOGEOGRAPHY
El género Proculus y sus cinco especies conocidas son redescritas, además se describe Proculus jicaquei sp. nov. Son sinonimizados: P. beckeri Zang, 1905 (syn. nov.) y P. densipennis Casey, 1914 (syn. nov.) con P. opacipennis (Thompson, 1857); P. mandibularis Casey, 1914 (syn. nov.) con P. burmeisteri Kuwert, 1891; y P. kraatzi Kuwert, 1898 (syn. nov.) y P. magister Casey, 1897 (syn. nov.) con P. mniszechi Kaup, 1868. Se incluyen claves de los adultos y las larvas, e información biogeográfica sobre cada especie. El género se distribuye desde México hasta Colombia. Proculus mniszechi es parapátrica con P. burmeisteri, aunque son parcialmente simpátridas, en la Sierra de las Minas, Sierra de Santa Cruz y Sierra de los Cuchumatanes de Guatemala, P. mniszechi se encuentra en un tipo de bosque mesófilo por arriba de los 1500 m y P. opacipennis se encuentra en otro tipo de bosque mesófilo por abajo de los 1500 m. Proculus opacipennis tiene una relación similar con P. opacus en la Sierra de los Cuchumatanes, donde P. opacus aparentemente reemplaza a P. mniszechi. Proculus goryi (Melly, 1833) se encuentra en la cadena de volcanes de la costa pacífica de Guatemala y Chiapas, México. Proculus jicaquei sp. nov. unicamente es conocida de una localidad de las montañas al noroeste de Yoro, Honduras. La hipótesis filogenética muestra que P. jicaquei está más relacionada con P. goryi, estas dos especies forman el clado hermano de todas las otras especies de Proculus. En tanto que P. mniszechi y P. burmeisteri son taxa hermanos, como por su parte lo son P. opacus y P. opacipennis.
The genus and its five known species are redescribed and P. jicaquei sp. nov. is described. Synonymies include P. beckeri Zang, 1905 with P. opacipennis (Thompson, 1857) (new synonymy), P. mandibularis Casey, 1914 with P. burmeisteri Kuwert, 1891 (new synonymy), P. magister Casey, 1897 with P. mniszechi Kaup, 1868 (new synonymy), P. densipennis Casey, 1914 with P. opacipennis (Thompson, 1857) (new synonymy), and P. kraatzi Kuwert, 1898 with P. mniszechi Kaup, 1868 (new synonymy). We include a phylogenetic analysis, keys for larvae and adults, and biogeographic information for each species. The genus occurs from Mexico to Colombia. Proculus mniszechi is parapatric with P. burmeisteri and partially sympatric with P. opacipennis in Sierra de las Minas, Sierra de Santa Cruz and Cuchumatan Mountains; P. mniszechi occurs in a type of cloud forest above 1500 m altitude, whereas P. opacipennis occurs in another cloud forest type below 1500 m. Proculus opacipennis has a similar relation with P. opacus Kuwert 1891 in the Cuchumatan Mountains, where P. opacus apparently replaces P. mniszechi. Proculus goryi (Melly, 1833) occurs in the volcanic chain of the Pacific coast of Guatemala and Chiapas, Mexico. Proculus jicaquei sp. nov. is known only from the mountains northwest of Yoro, Honduras. Phylogenetic hypothesis shows that P. jicaquei is most closely to P. goryi, these two taxa form a sister clade to all other Proculus species. Proculus mniszechi and P. burmeisteri are sister taxa, as are P. opacus and P. opacipennis
\u3ci\u3ePROCULUS\u3c/i\u3e, GIANT LATIN-AMERICAN PASSALIDS: REVISION, PHYLOGENY AND BIOGEOGRAPHY
El género Proculus y sus cinco especies conocidas son redescritas, además se describe Proculus jicaquei sp. nov. Son sinonimizados: P. beckeri Zang, 1905 (syn. nov.) y P. densipennis Casey, 1914 (syn. nov.) con P. opacipennis (Thompson, 1857); P. mandibularis Casey, 1914 (syn. nov.) con P. burmeisteri Kuwert, 1891; y P. kraatzi Kuwert, 1898 (syn. nov.) y P. magister Casey, 1897 (syn. nov.) con P. mniszechi Kaup, 1868. Se incluyen claves de los adultos y las larvas, e información biogeográfica sobre cada especie. El género se distribuye desde México hasta Colombia. Proculus mniszechi es parapátrica con P. burmeisteri, aunque son parcialmente simpátridas, en la Sierra de las Minas, Sierra de Santa Cruz y Sierra de los Cuchumatanes de Guatemala, P. mniszechi se encuentra en un tipo de bosque mesófilo por arriba de los 1500 m y P. opacipennis se encuentra en otro tipo de bosque mesófilo por abajo de los 1500 m. Proculus opacipennis tiene una relación similar con P. opacus en la Sierra de los Cuchumatanes, donde P. opacus aparentemente reemplaza a P. mniszechi. Proculus goryi (Melly, 1833) se encuentra en la cadena de volcanes de la costa pacífica de Guatemala y Chiapas, México. Proculus jicaquei sp. nov. unicamente es conocida de una localidad de las montañas al noroeste de Yoro, Honduras. La hipótesis filogenética muestra que P. jicaquei está más relacionada con P. goryi, estas dos especies forman el clado hermano de todas las otras especies de Proculus. En tanto que P. mniszechi y P. burmeisteri son taxa hermanos, como por su parte lo son P. opacus y P. opacipennis.
The genus and its five known species are redescribed and P. jicaquei sp. nov. is described. Synonymies include P. beckeri Zang, 1905 with P. opacipennis (Thompson, 1857) (new synonymy), P. mandibularis Casey, 1914 with P. burmeisteri Kuwert, 1891 (new synonymy), P. magister Casey, 1897 with P. mniszechi Kaup, 1868 (new synonymy), P. densipennis Casey, 1914 with P. opacipennis (Thompson, 1857) (new synonymy), and P. kraatzi Kuwert, 1898 with P. mniszechi Kaup, 1868 (new synonymy). We include a phylogenetic analysis, keys for larvae and adults, and biogeographic information for each species. The genus occurs from Mexico to Colombia. Proculus mniszechi is parapatric with P. burmeisteri and partially sympatric with P. opacipennis in Sierra de las Minas, Sierra de Santa Cruz and Cuchumatan Mountains; P. mniszechi occurs in a type of cloud forest above 1500 m altitude, whereas P. opacipennis occurs in another cloud forest type below 1500 m. Proculus opacipennis has a similar relation with P. opacus Kuwert 1891 in the Cuchumatan Mountains, where P. opacus apparently replaces P. mniszechi. Proculus goryi (Melly, 1833) occurs in the volcanic chain of the Pacific coast of Guatemala and Chiapas, Mexico. Proculus jicaquei sp. nov. is known only from the mountains northwest of Yoro, Honduras. Phylogenetic hypothesis shows that P. jicaquei is most closely to P. goryi, these two taxa form a sister clade to all other Proculus species. Proculus mniszechi and P. burmeisteri are sister taxa, as are P. opacus and P. opacipennis
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