A Tale of Four “Carp”: Invasion Potential and Ecological Niche Modeling

. We assessed the geographic potential of four Eurasian cyprinid fishes (common carp, tench, grass carp, black carp) as invaders in North America via ecological niche modeling (ENM). These “carp” represent four stages of invasion of the continent (a long-established invader with a wide distribution, a long-established invader with a limited distribution, a spreading invader whose distribution is expanding, and a newly introduced potential invader that is not yet established), and as such illustrate the progressive reduction of distributional disequilibrium over the history of species' invasions.We used ENM to estimate the potential distributional area for each species in North America using models based on native range distribution data. Environmental data layers for native and introduced ranges were imported from state, national, and international climate and environmental databases. Models were evaluated using independent validation data on native and invaded areas. We calculated omission error for the independent validation data for each species: all native range tests were highly successful (all omission values <7%); invaded-range predictions were predictive for common and grass carp (omission values 8.8 and 19.8%, respectively). Model omission was high for introduced tench populations (54.7%), but the model correctly identified some areas where the species has been successful; distributional predictions for black carp show that large portions of eastern North America are at risk.ENMs predicted potential ranges of carp species accurately even in regions where the species have not been present until recently. ENM can forecast species' potential geographic ranges with reasonable precision and within the short screening time required by proposed U.S. invasive species legislation

Cross-cultural Models of Customer Service: A Case of Country Park Recreation in Hong Kong

Hong Kong received more than 25 million visitors in 2006 with a forecasted 16 percent increase for 2007. Visitors from all over the world have brought more interactions between diverse visitors and local residents. Country parks (national parks) around the world increasingly serve as international visitor attractions and play an important role in the international tourism industry. Because of the demand for better responsiveness and high quality service from government agencies, the concern about how to serve a diverse international clientele has emerged as an important issue in parks and recreation management. Guided by previous research on cross-cultural differences, the purpose of this study was to examine the causal relationships between culture and marketing factors (i.e., service quality, satisfaction and behavioral intentions) or recreational factors (i.e., experience, crowding) within the context of country park recreation in Hong Kong. Surveys of visitors to the Pokfulam Country Park (PCP) near metropolitan Hong Kong were conducted in 2005-2006. Using a systematic random selection approach and purposive sampling at sites known to be heavily used by visitors with diverse cultural backgrounds, a sample of 253 Hong Kong residents, 153 Mainland Chinese Visitors, and 233 Westerners (including American, British, Australian, and European) was obtained. The data was formulated into a structural model using six constructs in the context of parks and recreation including culture, experience, crowding, service quality, satisfaction and behavioral intentions. The results showed acceptable validity and reliability of measures in the constructs across four models (i.e., the overall, Hong Kong residents, Mainland Chinese Visitors, and Westerners models). The structural equation modeling (SEM) analysis revealed the effects of culture on the marketing factors were much stronger than the effects of culture on the recreational factors. Further analysis of the three subgroup models showed patterns similar to those in the overall model, but culture had no significant effects on the other five constructs (i.e., there is no significant direct paths stemmed from culture to experience, crowding, service quality, satisfaction and behavioral intentions) in the Mainlander model. Discussion of the findings, management implications and future research are suggested

Pleiotropic Roles of VEGF in the Microenvironment of the Developing Thymus

Neonatal life marks the apogee of murine thymic growth. Over the first few days after birth, growth slows and the murine thymus switches from fetal to adult morphology and function; little is known about the cues driving this dramatic transition. In this study, we show for the first time (to our knowledge) the critical role of vascular endothelial growth factor (VEGF) on thymic morphogenesis beyond its well-known role in angiogenesis. During a brief window a few days after birth, VEGF inhibition induced rapid and profound remodeling of the endothelial, mesenchymal and epithelial thymic stromal compartments, mimicking changes seen during early adult maturation. Rapid transcriptional changes were seen in each compartment after VEGF inhibition, including genes involved in migration, chemotaxis, and cell adhesion as well as induction of a proinflammatory and proadipogenic signature in endothelium, pericytes, and mesenchyme. Thymocyte numbers fell subsequent to the stromal changes. Expression patterns and functional blockade of the receptors VEGFR2 and NRP1 demonstrated that VEGF mediates its pleiotropic effects through distinct receptors on each microenvironmental compartment of the developing mouse thymus

Ranking predictors of a sustained viral response for patients with chronic hepatitis C treated with pegylated interferon and ribavirin in Scotland

Objectives: From the literature on the hepatitis C virus, the existence of a gap between a sustained virologic response (SVR) attainable in randomized clinical trials (RCTs) versus routine practice is not clear. Further, in terms of the pretreatment prediction of SVR, to date, studies have focused only on reporting the magnitude of association (MOA) between each predictor and an SVR. They fail to acknowledge that a predictor with a large MOA is of little value to clinicians if it has low variability in the treatment population. Methods: Hepatitis C virus clinical databases were used to derive a large, representative cohort of Scottish pegylated interferon and ribavirin initiates. Results: Overall, 39% [123/315, 95% confidence interval (CI) 34–45%] of genotype 1 and 70% (414/594, 95% CI 66–73%) of genotype 2/3 patients achieved an SVR; this compares with the pooled estimates of 47% for genotype 1 (95% CI 41–52%) and 80% for genotype 2/3 (95% CI 75–85%) RCT participants. Significant predictors of SVR identified from logistic regression were ranked on the basis of the akaike information criteria (reflecting an approach that will account for each predictor’s MOA and variability) as follows: (i) genotype, % increase in akaike information criteria of the final model when variables are excluded, 58.49%; (ii) γ-glutamyl transferase, 18.64%; (iii) platelet count, 6.48%; (iv) alanine aminotransferase quotient, 4.63%; (v) ever infected with hepatitis B virus, 4.31% and (vi) sex, 3.10%. Conclusion: (i) The proportion of patients attaining an SVR in Scottish routine practice is marginally lower than in RCTs and (ii) other than genotype, γ-glutamyl transferase emerges as a valuable predictor of an SVR in routine practice. Further, we demonstrate an approach to more clearly discern the predictive value of response predictors

In situ X-ray and neutron diffraction of the Ruddlesden–Popper compounds (RE2−xSrx)0.98(Fe0.8Co0.2)1−yMgyO4−δ (RE=La, Pr): Structure and CO2 stability

The crystal structure of the Ruddlesden-Popper compounds (La 1.0Sr1.0)0.98Fe0.8Co 0.2O4-δ and (La1.2Sr0.8) 0.98(Fe0.8Co0.2)0.8Mg 0.2O4-δ was investigated at 1000 °C in N 2 (aO2=1×10-4) by in-situ powder neutron diffraction. In-situ powder X-ray diffraction (PXD) was also employed to investigate the temperature dependence of the lattice parameters of the compounds in air and the oxygen activity dependence of the lattice parameters at 800 °C and 1000 °C. The thermal and chemical expansion coefficients, determined along the two crystallographic directions of the tetragonal unit cell, are highly anisotropic. The equivalent pseudo-cubic thermal and chemical expansion coefficients are in agreement with values determined by dilatometry. The chemical stability in CO2 containing environments of various Ruddlesden-Popper compounds with chemical formula (RE2-xSr x)0.98(Fe0.8Co0.2) 1-yMgyO4-δ (RE=La, Pr), as well as their stability limit in H2/H2O=4.5 were also determined by in-situ PXD for x=0.9, 1.0 and y=0, 0.2. © 2013 Elsevier Inc. All rights reserved