Gaussian free-energy dependence of electron-transfer rates in iridium complexes     

Fox LS  Kozik M  Winkler JR  Gray HB 《Science (New York, N.Y.)》1990,247(4946):1069-1071

The kinetics of photoinduced electron-transfer (ET) reactions have been measured in a series of synthetic donor-acceptor complexes. The electron donors are singlet or triplet excited iridium(I) dimers (Ir(2)), and the acceptors are N-alkylpyridinium groups covalently bound to phosphinite ligands on the Ir(2) core. Rate constants for excited-state ET range from 3.5 x 10(6) to 1.1 x 10(11) per second, and thermal back ET (pyridinium radical to Ir(2)(+)) rates vary from 2.0 x 10(10) to 6.7 x 10(7) per second. The variation of these rates with driving force is in remarkably good agreement with the Marcus theory prediction of a Gaussian free-energy dependence.  相似文献   

Pre-weaning morbidity and mortality of llamas and alpacas     

MS Sharpe  LK Lord  TE Wittum  DE Anderson 《Australian veterinary journal》2009,87(1-2):56-60

Objectives   To describe the morbidity and mortality patterns and identify factors associated with morbidity in pre-weaning llamas and alpacas.
Design   Cross-sectional observational study of 287 crias born on four farms in Ohio, USA
Procedure   Historical data representing all crias born over a 6-year period were obtained from two llama farms and two alpaca farms in Ohio. Multivariable generalised linear mixed effects regression models were used to identify factors associated with morbidity outcomes.
Results   In total, 105 (37%) of the llamas and alpacas had some reported morbidity during the pre-weaning period, and mortality rate was 2.1%. In addition, 51 (18%) of llamas and alpacas experienced morbidity because of infectious disease, and 47 (16%) experienced morbidity during the neonatal period. The three most commonly reported morbidity events were undifferentiated diarrhoea (23%), umbilical hernia (16%) and unspecified infectious disease (15%). Difficult birth was an important risk factor for pre-weaning morbidity in this population.
Conclusions   Camelid veterinarians and their clients can expect that pre-weaning health events are common among crias, although mortality is low. Crias experiencing difficult births may require additional monitoring for health events during the pre-weaning period.  相似文献   

Modelling the oceanic habitats of two pelagic species using recreational fisheries data          下载免费PDF全文

Stephanie Brodie  Alistair J. Hobday  James A. Smith  Jason D. Everett  Matt D. Taylor  Charles A. Gray  Iain M. Suthers 《Fisheries Oceanography》2015,24(5):463-477

Defining the oceanic habitats of migratory marine species is important for both single species and ecosystem‐based fisheries management, particularly when the distribution of these habitats vary temporally. This can be achieved using species distribution models that include physical environmental predictors. In the present study, species distribution models that describe the seasonal habitats of two pelagic fish (dolphinfish, Coryphaena hippurus and yellowtail kingfish, Seriola lalandi), are developed using 19 yr of presence‐only data from a recreational angler‐based catch‐and‐release fishing programme. A Poisson point process model within a generalized additive modelling framework was used to determine the species distributions off the east coast of Australia as a function of several oceanographic covariates. This modelling framework uses presence‐only data to determine the intensity of fish (fish km^?2), rather than a probability of fish presence. Sea surface temperature (SST), sea level anomaly, SST frontal index and eddy kinetic energy were significant environmental predictors for both dolphinfish and kingfish distributions. Models for both species indicate a greater fish intensity off the east Australian coast during summer and autumn in response to the regional oceanography, namely shelf incursions by the East Australian Current. This study provides a framework for using presence‐only recreational fisheries data to create species distribution models that can contribute to the future dynamic spatial management of pelagic fisheries.  相似文献   

Epizootics in Industrial Livestock Production: Preventable Gaps in Biosecurity and Biocontainment          下载免费PDF全文

J. H. Leibler  K. Dalton  A. Pekosz  G. C. Gray  E. K. Silbergeld 《Zoonoses and public health》2017,64(2):137-145

While technological advances in animal husbandry have facilitated increases in global meat production, the high density and geographic concentration of food animal production facilities pose risks of infectious disease transmission. The scale of the 2014–2015 highly pathogenic avian influenza H5N2 outbreak in the United States demonstrates the challenges in achieving pathogen control within and around industrial animal facilities using existing technologies. We discuss gaps in current practice in two specific systems within these facilities – ventilation and waste management – which are under‐recognized as important drivers of microbial porosity. The development of innovative ventilation systems to reduce influx and efflux of pathogens is critically needed, and cross‐sectoral partnerships should be incentivized to do so. Adapting current human biosolid treatment technologies for farm applications, reducing animal stocking density and shifting waste management responsibility from farmer to corporation would reduce risk from current manure management systems. While innovative approaches to functionally altering the industrial food animal production system remain important priorities to promote sustainability, our intention here is to identify gaps within the current system that allow for pathogen emergence and transmission and address specific areas in which technological, administrative or policy changes are necessary to mitigate these risks.  相似文献