8,709 research outputs found
Notes on the Ecology of Xyloryctes Jamaicensis (Coleoptera: Scarabaeidae) in Southern Ontario
Excerpt: The comprehensive survey of literature on the biology of the Scarabaeidae by Ritcher (1958) indicates that the ecology of many large groups is known from a study of very few species. Such is the case with the rhinoceros beetles in the subfamily Dynastinae. From 1960 to 1965 I had many opportunities to observe the rhinoceros beetle Xyloryctes jamaicensis (Drury) in a woodlot near Wheatley, Ontario, on the north shore of Lake Erie. My notes, although fragmentary, suggest areas of further research
Extended Object Tracking: Introduction, Overview and Applications
This article provides an elaborate overview of current research in extended
object tracking. We provide a clear definition of the extended object tracking
problem and discuss its delimitation to other types of object tracking. Next,
different aspects of extended object modelling are extensively discussed.
Subsequently, we give a tutorial introduction to two basic and well used
extended object tracking approaches - the random matrix approach and the Kalman
filter-based approach for star-convex shapes. The next part treats the tracking
of multiple extended objects and elaborates how the large number of feasible
association hypotheses can be tackled using both Random Finite Set (RFS) and
Non-RFS multi-object trackers. The article concludes with a summary of current
applications, where four example applications involving camera, X-band radar,
light detection and ranging (lidar), red-green-blue-depth (RGB-D) sensors are
highlighted.Comment: 30 pages, 19 figure
Critical market shares for investors and access seekers and competitive models in fibre networks
In this paper we consider and evaluate NGA architectures which meet the foreseeable future bandwidth demand and allow for highest bandwidth and quality for end-users and which no longer rely on copper cable elements. These are FTTH architectures only. From all available FTTH architectures we concentrate on the two most relevant architectures in Europe, Ethernet Point-to-Point and GPON. We assume the incumbent to be the investor in the NGA network infrastructure. If the NGA architecture is based on a Point-to-Point fibre plant we have modelled the competitors as using unbundled fibre loops as the wholesale access service. If the architecture is based on a Point-to-Multipoint fibre plant, we consider an active wholesale access (bitstream access) at the MPoP or at the core network node locations. Our basic modelling relies upon an engineering bottom-up cost modelling approach. We model the total cost of the services considered under efficient conditions, taking into account the cost of all network elements needed to produce these services in the specific architecture deployed. This approach is coherent with a Long Run Incremental Cost approach as applied in regulatory economics. Our modelling approach generates a broad set of results including the relative performance of the various network architectures, investment requirements and the degree of profitable coverage. In this paper, however, we focus on the results on the potential for competition and potential market structures in an NGA environment. --NGA architecture,cost modelling,FTTH,coverage,access models,unbundling
Neutrino-driven winds in the aftermath of a neutron star merger: nucleosynthesis and electromagnetic transients
We present a comprehensive nucleosynthesis study of the neutrino-driven wind
in the aftermath of a binary neutron star merger. Our focus is the initial
remnant phase when a massive central neutron star is present. Using tracers
from a recent hydrodynamical simulation, we determine total masses and
integrated abundances to characterize the composition of unbound matter. We
find that the nucleosynthetic yields depend sensitively on both the life time
of the massive neutron star and the polar angle. Matter in excess of up to becomes unbound until . Due to
electron fractions of mainly nuclei with mass
numbers are synthesized, complementing the yields from the earlier
dynamic ejecta. Mixing scenarios with these two types of ejecta can explain the
abundance pattern in r-process enriched metal-poor stars. Additionally, we
calculate heating rates for the decay of the freshly produced radioactive
isotopes. The resulting light curve peaks in the blue band after about . Furthermore, high opacities due to heavy r-process nuclei in the dynamic
ejecta lead to a second peak in the infrared after .Comment: 15 pages, 18 figures, 2 tables, accepted by Ap
Caveat Emptor: Does Bitcoin Improve Portfolio Diversification?
Bitcoin is an unregulated digital currency originally introduced in 2008 without legal tender status. Based on a decentralized peer-to-peer network to confirm transactions and generate a limited amount of new bitcoins, it functions without the backing of a central bank or any other monitoring authority. In recent years, Bitcoin has seen increasing media coverage and trading volume, as well as major capital gains and losses in a high volatility environment. Interestingly, an analysis of Bitcoin returns shows remarkably low correlations with traditional investment assets such as other currencies, stocks, bonds or commodities such as gold or oil. In this paper, we shed light on the impact an investment in Bitcoin can have on an already well-diversified investment portfolio. Due to the non-normal nature of Bitcoin returns, we do not propose the classic mean-variance approach, but adopt a Conditional Value-at-Risk framework that does not require asset returns to be normally distributed. Our results indicate that Bitcoin should be included in optimal portfolios. Even though an investment in Bitcoin increases the CVaR of a portfolio, this additional risk is overcompensated by high returns leading to better return-risk ratios
Markowitz Revisited: Social Portfolio Engineering
In recent years socially responsible investing has become an increasingly more
popular subject with both private and institutional investors. At the same time, a
number of scientific papers have been published on socially responsible investments
(SRIs), covering a broad range of topics, from what actually defines SRIs to the
financial performance of SRI funds in contrast to non-SRI funds. In this paper, we
revisit Markowitz' Portfolio Selection Theory and propose a modification allowing
to incorporate not only asset-specific return and risk but also a social responsibility
measure into the investment decision making process. Together with a risk-free asset,
this results in a three-dimensional capital allocation plane that allows investors to
custom-tailor their asset allocations and incorporate all personal preferences regarding
return, risk and social responsibility. We apply the model to a set of over 6,231
international stocks and find that investors opting to maximize the social impact
of their investments do indeed face a statistically significant decrease in expected
returns. However, the social responsibility/risk-optimal portfolio yields a statistically
significant higher social responsibility rating than the return/risk-optimal portfolio
Impact of glucuronide interferences on therapeutic drug monitoring of posaconazole by tandem mass spectrometry
Background: Posaconazole is a novel antifungal drug for oral application intended especially for therapy of invasive mycoses. Due to variable gastrointestinal absorption, adverse side effects, and suspected drug-drug interactions, therapeutic drug monitoring (TDM) of posaconazole is recommended. Method: A fast ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for quantification of posaconazole with a run-time <3 min was developed and compared to a LC-MS/MS method and HPLC method with fluorescence detection. Results: During evaluation of UPLC-MS/MS, two earlier eluting peaks were observed in the MRM trace of posaconazole. This was only seen in patient samples, but not in spiked calibrator samples. Comparison with LC-MS/MS disclosed a significant bias with higher concentrations measured by LC-MS/MS, while UPLC-MS/MS showed excellent agreement with the commercially available HPLC method. In the LC-MS/MS procedure, comparably wide and left side shifted peaks were noticed. This could be ascribed to in-source fragmentation of conjugate metabolites during electrospray ionisation. Precursor and product ion scans confirmed the assumption that the additional compounds are posaconazole glucuronides. Reducing the cone voltage led to disappearance of the glucuronide peaks. Slight modification of the LC-MS/MS method enabled separation of the main interference, leading to significantly reduced deviation. Conclusions: These results highlight the necessity to reliably eliminate interference from labile drug metabolites for correct TDM results, either by sufficient separation or selective MS conditions. The presented UPLC-MS/MS method provides a reliable and fast assay for TDM of posaconazole. Clin Chem Lab Med 2010; 48:1723-31
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