38,457 research outputs found
Central American Temnocerus Thunberg, 1815 (Coleoptera: Rhynchitidae)
Twenty eight species of Temnocerus Thunberg, 1815 are recognized from Central America (Mexico to Panama) with eight previously described species and 20 new species as follows: T. abdominalis (Voss), T. chiapensis n. sp., T. chiriquensis (Sharp), T. confertus (Sharp), T. cyaneus n. sp., T. ellus n. sp., T. giganteus n. sp., T. guatemalenus (Sharp), T. guerrerensis n. sp., T. herediensis n. sp., T. mexicanus n. sp., T. michoacensis n. sp., T. minutus n. sp., T. niger n. sp., T. oaxacensis n. sp., T. obrieni, n. sp., T. oculatus (Sharp), T. potosi n. sp., T. pseudaeratus n. sp., T. pueblensis n. sp., T. pusillus (Sharp), T. regularis (Sharp), T. rostralis n. sp., T. rugosus n. sp., T. salvensis n. sp., T. tamaulipensis n. sp., T. thesaurus (Sharp) and T. yucatensis n. sp. Rhynchites debilis Sharp is placed in synonymy with Temnocerus guatemalenus (Sharp) and Pselaphorhynchites lindae Hamilton is placed in synonymy with Temnocerus regularis (Sharp). A key to species based on external characters and male genitalia is provided as well as digital images, aedeagus drawings, and map distributions
Account of Pegu and the Voyage to Cambodia and Siam in 1718 by Alexander Hamilton, edited by Michael W. Charney
Captain Alexander Hamilton collated an account of his voyage to Cambodia and Siam in 1718 with accounts of his experiences in Pegu and elsewhere on earlier travels, as well as information he had gathered about certain other locations (such as Arakan) in his A New Account of the East Indies (Edinburgh, 1727). While the original account also included accounts of parts of the Malay world and âCochinchina,â these have been excluded from the following text. The account begins with a brief account of Chittagong and concludes with eastern mainland Southeast Asia. Edited for the SBBR by Michael W. Charney
Negative Group Velocity
The group velocity for pulses in an optical medium can be negative at
frequencies between those of a pair of laser-pumped spectral lines. The gain
medium then can amplify the leading edge of a pulse resulting in a time advance
of the pulse when it exits the medium, as has been recently demonstrated in the
laboratory. This effect has been called superluminal, but, as a classical
analysis shows, it cannot result in signal propgation at speeds greater than
that of light in vacuum.Comment: v3 adds discussion of "rephasing", and adds a figure. v4 adds
references to the early history of negative group velocity, and adds a
figure; thanks to Alex Grani
The myths and realities of Bayesian chronological modeling revealed
We review the history of Bayesian chronological modeling in archaeology and demonstrate that there has been a surge over the past several years in American archaeological applications. Most of these applications have been performed by archaeologists who are self-taught in this method because formal training opportunities in Bayesian chronological modeling are infrequently provided. We define and address misconceptions about Bayesian chronological modeling that we have encountered in conversations with colleagues and in anonymous reviews, some of which have been expressed in the published literature. Objectivity and scientific rigor is inherent in the Bayesian chronological modeling process. Each stage of this process is described in detail, and we present examples of this process in practice. Our concluding discussion focuses on the potential that Bayesian chronological modeling has for enhancing understandings of important topics
Stable isotopes, chronology and Bayesian models for the Viking archaeology of north-east Iceland
This paper reviews the results of a long-term research project that used stable isotope analyses (δ13C, δ15N, δ34S) and Bayesian mixing models to better model the chronology for a presumed Viking Age cemetery at HofstaĂ°ir, near Lake MĂ˝vatn in north-east Iceland. δ13C and radiocarbon dating indicated that many of the individuals consumed a large amount of marine protein, which results in a marine reservoir effect (MRE), making ages older than expected. In addition to the MRE, geological activity in the region has the potential to introduce massive quantities of radioactive âdeadâ carbon into the freshwater system, resulting in a very large freshwater reservoir effect (FRE) that can offset radiocarbon ages on the order of a few thousand years. The radiocarbon dates of organisms that derive an unknown proportion of their carbon from both marine and freshwater reservoirs are extremely difficult to âcorrectâ, or, more appropriately, model. The research not only highlights the complexities of dealing with multiple reservoirs, but also how important it is to develop models that are temporally and geographically relevant to the site under study. Finally, it shows how this data can be used to inform the development of chronological models for refining the dating for archaeological activity
The Coase Conjecture in Continuous Time: Imperfect Durability Endogenous Durability and Aftermarkets
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