8,985 research outputs found
Fund family tournament and performance consequences: evidence from the UK fund industry
By applying tournament analysis to the UK Unit Trusts data, the results support significant risk shifting in the family tournament; i.e. interim winning managers tend to increase their level of risk exposure more than losing managers. It also shows that the risk-adjusted returns of the winners outperform those of the losers following the risk taking, which implies that risk altering can be regarded as an indication of managers’ superior ability. However, the tournament behaviour can still be a costly strategy for investors, since winners can be seen to beat losers in the observed returns due to the deterioration in the performance of their major portfolio holdings
Charged lepton flavor violating Higgs decays at future colliders
After the discovery of the Higgs boson, several future experiments have been
proposed to study the Higgs boson properties, including two circular lepton
colliders, the CEPC and the FCC-ee, and one linear lepton collider, the ILC. We
evaluate the precision reach of these colliders in measuring the branching
ratios of the charged lepton flavor violating Higgs decays ,
and . The expected upper bounds on the
branching ratios given by the circular (linear) colliders are found to be
, and at 95\% CL, which are improved by
one to two orders compared to the current experimental bounds. We also discuss
the constraints that these upper bounds set on certain theory parameters,
including the charged lepton flavor violating Higgs couplings, the
corresponding parameters in the type-III 2HDM, and the new physics cut-off
scales in the SMEFT, in RS models and in models with heavy neutrinos.Comment: 20 pages, 2 figures (extend the CEPC study to the FCC-ee and the ILC,
and to match the published version
Daylight-driven rechargeable antibacterial and antiviral nanofibrous membranes for bioprotective applications.
Emerging infectious diseases (EIDs) are a significant burden on global economies and public health. Most present personal protective equipment used to prevent EID transmission and infections is typically devoid of antimicrobial activity. We report on green bioprotective nanofibrous membranes (RNMs) with rechargeable antibacterial and antiviral activities that can effectively produce biocidal reactive oxygen species (ROS) solely driven by the daylight. The premise of the design is that the photoactive RNMs can store the biocidal activity under light irradiation and readily release ROS under dim light or dark conditions, making the biocidal function "always online." The resulting RNMs exhibit integrated properties of fast ROS production, ease of activity storing, long-term durability, robust breathability, interception of fine particles (>99%), and high bactericidal (>99.9999%) and virucidal (>99.999%) efficacy, which enabled to serve as a scalable biocidal layer for protective equipment by providing contact killing against pathogens either in aerosol or in liquid forms. The successful synthesis of these fascinating materials may provide new insights into the development of protection materials in a sustainable, self-recharging, and structurally adaptive form
基于Kriging模型的地面气温空间插值研究
This paper aims to describe spatial interpolation methods to estimate surface air temperatures (SATs). The SAT at a particular location where SAT observations are not available is estimated through a Kriging interpolation between SAT measurements from 192 meteorological sites at which daily SAT observations have been obtained. A temporal de-trending method based on a Fourier series is used to model and remove the annual trend in original data in order to ensure the stationarity of de-trended data from which kriging parameters are determined. Furthermore, a spatial or surface de-trending in terms of geographic coordinates including altitude, latitude and longitude of each location is adopted in a Kriging model. Besides a Kriging model, an inverse distance weighting (IDW) interpolation method is tested as a comparison. The accuracies of both spatial interpolation approaches are assessed by calculating and comparing their mean absolute error (MAE) and root mean square error (RMSE) when taking each meteorological site as the target location in a cross-validation procedure. The results show that the Kriging model performs better than the IDW method at 174 sites. In addition, the temporal and spatial de-trending methods make the main contribution to the accurate capture of spatial correlations of SATs in the study area in a Kriging process
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