On model selection criteria for climate change impact studies

Climate change impact studies inform policymakers on the estimated damages of future climate change on economic, health and other outcomes. In most studies, an annual outcome variable is observed, e.g. annual mortality rate, along with higher-frequency regressors, e.g. daily temperature and precipitation. Practitioners use summaries of the higher-frequency regressors in fixed effects panel models. The choice over summary statistics amounts to model selection. Some practitioners use Monte Carlo cross-validation (MCCV) to justify a particular specification. However, conventional implementation of MCCV with fixed testing-to-full sample ratios tends to select over-fit models. This paper presents conditions under which MCCV, and also information criteria, can deliver consistent model selection. Previous work has established that the Bayesian information criterion (BIC) can be inconsistent for non-nested selection. We illustrate that the BIC can also be inconsistent in our framework, when all candidate models are misspecified. Our results have practical implications for empirical conventions in climate change impact studies. Specifically, they highlight the importance of a priori information provided by the scientific literature to guide the models considered for selection. We emphasize caution in interpreting model selection results in settings where the scientific literature does not specify the relationship between the outcome and the weather variables.Comment: Additional simulation results available from authors by reques

Effects of uncertainties and errors on Lyapunov control

Lyapunov control (open-loop) is often confronted with uncertainties and errors in practical applications. In this paper, we analyze the robustness of Lyapunov control against the uncertainties and errors in quantum control systems. The analysis is carried out through examinations of uncertainties and errors, calculations of the control fidelity under influences of the certainties and errors, as well as discussions on the caused effects. Two examples, a closed control system and an open control system, are presented to illustrate the general formulism.Comment: 4 pages, 5 figure

The origin of the lead-rich stars in Galactic halo: investigation of the model parameters for the s-process

Several stars at the low-metallicity extreme of the Galactic halo show large spreads of [Pb/hs]. Theoretically, a s-process pattern should be obtained from an AGB star with fixed metallicity and initial mass. For the third dredge-up and the s-process model, several important properties depend primarily on the core mass of AGB stars. Zijlstra (2004) reported that the initial-final-mass relation steepens at low metallicity, due to low mass-loss efficiency. This perhaps affects the model parameters of the AGB stars, e.g. the overlap factor and the neutron irradiation time, in particular at low metallicity. The calculated results show indeed that the overlap factor and the neutron irradiation time are significantly small at low metallicities, especially for 3.0Msun AGB stars. The scatter of [Pb/hs] found in low metallicities can therefore be explained naturally when varying the initial mass of the low-mass AGB stars.Comment: 5 pages, 7 EPS figures. Accepted for publication in MNRA

Mold Fabrication for 3D Dual Damascene Imprinting

Previously, a damascene process based on nanoimprint lithography has been proposed (Schmid G M, et al. in J Vac Sci Technol B 24(3) 1283, 2006) to greatly reduce the fabrication steps of metal interconnection in integrated circuit. For such a process to become a viable technique, a mold having two pattern levels with precise alignment between them must be fabricated first. To this end, this work demonstrates a “self-aligned” fabrication process where the two pattern levels would be perfectly aligned if ignoring the noise during e-beam writing. The process is based on one EBL on a bi-layer resist stack, with the sensitivity for the top layer much higher than that of the bottom layer, which enables separate pattern transfer of the two pattern levels. Using ZEP-520A and poly(dimethylglutarimide) (PMGI) resists, we fabricated pillars having a diameter of 150 nm sitting on ridges having a width of 1.5 μm, which can be used to create via-holes and trenches for IC interconnect by nanoimprint lithography. The current process can also find applications in other areas that require two-level patterning with precise alignment between them

Modification of the National Weather Service Distributed Hydrologic Model for subsurface water exchanges between grids

To account for spatial variability of precipitation, as well as basin physiographic properties, the National Weather Service (NWS) has developed a distributed version of its hydrologic component, termed the Hydrology Laboratory-Research Distributed Hydrologic Model (HL-RDHM). Because channels are the only source of water exchange between neighboring computational elements, the absence of such exchange has been identified as a weakness in the model. The primary objective of this paper is to modify the model structure to account for subsurface water exchanges without dramatically altering the conceptual framework of the water balance module. The subsurface exchanges are established by partitioning the slow response components released from the lower layer storages into two parts: the first part involves the grid's conceptual channel, while the second is added to the lower layer storages of the downstream pixel. Realizing the deficiency of the water balance module to locate the lower zone layers in sufficient depths, a complementary study is conducted to test the feasibility of further improvement in the modified model by equally shifting downward the lower zone layers of all pixels over the basin. The Baron Fork at Eldon, Oklahoma, is chosen as the test basin. Ten years of grid-based multisensor precipitation data are used to investigate the effects of the modification, plus shifting the lower zone layers on model performance. The results show that the modified-shifted HL-RDHM can markedly improve the streamflow simulations at the interior point, as well as very high peak-flow simulations at the basin's outlet. Copyright 2011 by the American Geophysical Union

Phenotypic and genotypic characterisation of biofilm formation in staphylococcus capitis

Biofilm formation is a major concern in infection caused by S. capitis in newborn babies. Phenotypic and genotypic characteristics of biofilm formation in clinical S. capitis isolates from newborns in Royal Woman’s Hospital in Melbourne were investigated. Of 60 S. capitis isolates, 52 belonged to the subspecies urealyticus and the remaining eight to the subsp. capitis. The most prevalent types, that persisted for 6 years in the unit belonged to subsp. urealyticus. Biofilm formation and antibiotic resistance were also mainly displayed by subsp. urealyticus. Sequence analysis showed that the ica operon in S. capitis was 4160 bp in length. PCR demonstrated its presence in all the isolates. The ica operon harboured in S. capitis is closely related to that of other species of staphylococci. It contains four structural genes icaA, icaD, icaB and icaC, which are co-transcribed from the icaA promoter. A negative regulator icaR gene is located upstream of icaA and transcribed in an opposite orientation. In sillico analysis of ica operon demonstrated the putative function and mechanisms of ICA proteins in polysaccharide biosynthesis and the origin on ica genes present in S. capitis genomes. In vitro biofilm formation and the expression of biofilm-related genes induced by sub-inhibitory concentrations of erythromycin revealed different responses. The expression of icaA and sarA genes was up-regulated, and icaR was down-regulated in the subsp. urealyticus biofilm producer. In contrast, a reverse expression was displayed by the biofilm-negative subsp. capitis isolate. This suggests biofilm formation in S. capitis is regulated by icaR and sarA, and the two subspecies may adopt different regulatory pathways in the two subspecies. The erythromycin induced biofilm formation may have clinical implications according to the doses of erythromycin used clinically. Gene transformation protocols for S. capitis were developed and optimised and will be used as a platform for future work. In summary, this study revealed distinctive phenotypic and genotypic characteristics of the two subspecies of S. capitis which relate to their epidemiology under the clinical setting of newborn intensive care. Isolates of the predominant subsp. urealyticus clones were characterised by their higher antibiotic resistance and biofilm formation ability, and distinct gene expression profiles. Differentiating the subspecies S. capitis revealed will be valuable in understanding their role in bloodstream infections of newborns in hospitals

targeted therapies in conversion therapy in mcrc a systematic review and meta analysis

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