A DOUBLE HURDLE APPROACH TO EVALUATING NON-RESIDENTIAL WILDLIFE WATCHING IN THE UNITED STATES

In 1996, over 62 million U.S. residents participated in wildlife watching and spent in excess of 29 billion dollars in this recreational activity. Wildlife watching can be defined as the observation, study, and enjoyment of natural areas and its wild fauna and flora. Residential wildlife watching takes place within one mile of the participant's residence and is often an incidental or secondary activity. Non-residential wildlife watching refers to recreation taking place at a distance of at least one mile from the participant's residence. In recent years, a sharp decline in the number of wildlife watchers has been noted. Between 1991 and 1996, the number of wildlife watchers decreased by 17 percent. During this time interval, the largest decline in participation was observed in non-residential viewing. The number of non-residential wildlife watchers declined by 21 percent. This trend is damaging to towns and communities, especially rural communities which largely depend on recreation dollars. The mitigation or reversal of this trend hinges upon the identification of factors affecting participation and expenditures on wildlife viewing. The determining role of several socioeconomic attributes in explaining participation and expenditures on nature-related recreation has been widely studied in the leisure and recreation literature. However, most of these past studies have focused on fishing and hunting activities rather than the equally important non-residential wildlife watching. Hence, this study evaluates participation decisions and the extent of the participation in non-residential wildlife watching in the United States. Keywords: wildlife watching, limited dependent variables, double hurdlewildlife watching, limited dependent variables, double hurdle, Resource /Energy Economics and Policy,

The Role of the IL-12 Cytokine Family in Directing T-Cell Responses in Oral Candidosis

Candida albicans is an opportunistic fungal pathogen that normally exists as a harmless commensal in humans. In instances where host debilitation occurs, Candida can cause a range of clinical infections, and whilst these are primarily superficial, effecting mucosal membranes, systemic infections can develop in severely immunocompromised individuals. The mechanism of host immunity during commensal carriage of C. albicans has been intensively studied. In this paper, we present the most recent information concerning host recognition of C. albicans leading to cytokine production and the subsequent T-cell responses generated in response to C. albicans. Particular focus is given to the role of the IL-12 cytokine family including IL-12, IL-23, IL-27, and IL-35, in host immunity to Candida. CD4+ T-cells are considered crucial in the regulation of immunity and inflammation. In this regard, the role of Th1/2, helper cells, together with the recently identified Th17 and Treg cells in candidosis will be discussed. Understanding the detailed mechanisms that underlie host immunity to Candida not only will be of benefit in terms of the infections caused by this organism but could also be exploited in the development of therapeutic interventions for other diseases

Atrazine Transport Within a Coastal Zone in Southeastern Puerto Rico: a Sensitivity Analysis of an Agricultural Field Model and Riparian Zone Management Model

Agrichemical runoff from farmland may adversely impact coastal water quality. Two models, the Agricultural Policy/Environmental eXtender (APEX) and the Riparian Ecosystem Management Model (REMM), were used to evaluate the movement of the herbicide atrazine to the Jobos Bay National Estuarine Research Reserve from adjacent fields. The reserve is located on Puerto Rico’s southeast coast. Edge-of-field atrazine outputs simulated with the APEX were routed through a grass-forest buffer using the REMM. Atrazine DT50 (half-life) values measured in both field and buffer soils indicated that accelerated degradation conditions had developed in the field soil due to repeated atrazine application. APEX simulations examined both the measured field and buffer soil atrazine DT50 and the model’s default value. The use of the measured field soil atrazine degradation rate in the APEX resulted in 33 % lower atrazine transport from the field. REMMsimulations indicated that the buffer system had the potential to reduce dissolved atrazine transport in surface runoff by 77%during non-tropical stormevents by increasing infiltration, slowing transport, and increasing time for pesticide degradation. During a large runoff event due to a tropical stormthat occurred close to the time of an atrazine application, the REMM simulated only a 37 % reduction in atrazine transport. The results indicate that large storm events soon after herbicide application likely dominate herbicide transport to coastal waters in the region. These results agree with water quality measurements in the reserve. This study demonstrated the sensitivity of these models to variations in DT50 values in evaluating atrazine fate and transport in the region and emphasizes that the use of measured DT50 values can improve model accuracy

Candida biofilms and oral candidosis : treatment and prevention

In recent years, there has been a significant increase in the incidence of human fungal infections (60). A number of factors have been implicated with this increase, but it is generally accepted that the main influences relate to the more widespread provision of new medical practices, such as immunosuppressive therapy and use of broad spectrum antibiotics, and invasive surgical procedures such as solid organ or bone marrow transplantation. Infections may either be superficial, affecting the skin, hair, nails and mucosal membranes, or systemic, involving major body organs (95). The risk of systemic infection appears to be enhanced in cases where the individual is already colonized by Candida (71). With regard to superficial mucosal infections, the continued spread of HIV infection (29) and the more extensive use of inhaled steroids (36) have also played significant roles

Application of three-dimensional fault stress models for assessment of fault stability for CO2 storage sites

Carbon Capture and Storage (CCS) is a key technology for a low-carbon energy future and will have an important role on the economic future of the UK Continental Shelf (UKCS). The East Irish Sea Basin (EISB) is a prospective area for CCS in the western UKCS. 3D seismic from the EISB were used in this study to characterise the fault network and potential fault reactivation risks associated with CO2 injection. Two main structural domains are present: a Northern domain with NW-SE faults, and a Southern domain with faults following a N-S orientation. The main storage sites consist of structural closures in Triassic strata of the Sherwood Sandstone Formation (SSF), overlain by alternations of mudstones and evaporites of the Triassic Mercia Mudstone Group (MMG). The closures occur predominantly at fault-bounded horsts, with adjacent grabens filled by thick sequences of the Triassic Mercia Mudstone Group (MMG). The fault framework was used to test, in 3D, the stress model published for the EISB and assess the fault reactivation risk associated with CO2 storage. Slip tendency values were predominantly below 0.6, suggesting the presence of stable structures in the EISB. Under the tested conditions, faults are capable of withstanding pressure increases between 3 MPa and 10 MPa before the onset of slip. The limited fault reactivation risk suggests CCS operations are suitable prospects for the EISB. This work demonstrates the additional value gained from integration of accurately constrained fault geometries in 3D stress models

Space Operations in the Suborbital Space Flight Simulator and Mission Control Center: Lessons Learned with XCOR Lynx

This study was conducted to better understand the performance of the XCOR Lynx vehicle. Because the Lynx development was halted, the best knowledge of vehicle dynamics can only be found through simulator flights. X-Plane 10 was chosen for its robust applications and accurate portrayal of dynamics on a vehicle in flight. The Suborbital Space Flight Simulator (SSFS) and Mission Control Center (MCC) were brought to the Applied Aviation Sciences department in fall 2015 at Embry-Riddle Aeronautical University, Daytona Beach campus. This academic and research tool is a department asset capable of providing multiple fields of data about suborbital simulated flights. This tool will allow flight navigators to assess different aspects of a suborbital flight dynamics and generate various trajectory maps to establish procedures and preventive measures when the vehicle goes through the NAS. It was found that the XCOR Lynx is an unstable platform but has good glide capabilities. This information is useful to pilots who may someday fly the XCOR Lynx as well as air traffic controllers who may have Lynx operations at their airports

Role of Bacterial Lipopolysaccharide in Enhancing Host Immune Response to Candida albicans

Human infections involving yeast of the genus Candida often occur in the presence of bacteria, and, as such, it is important to understand how these bacteria influence innate host immunity towards Candida. Dectin-1 is a cell receptor of macrophages for Candida albicans recognition. The aim of this study was to examine dectin-1 expression by monocytes after stimulation with bacterial lipopolysaccharide (LPS), followed by heat-killed C. albicans (HKC). Freshly isolated human peripheral blood monocytes (PBMCs) and human monocytes cell line (THP-1) cells expressed low levels of dectin-1. Stimulation with LPS and GM-CSF/IL-4 was found to increase dectin-1 expression in both CD14(+) human PBMC and THP-1 cells. Enhanced dectin-1 expression resulted in increased phagocytosis of Candida. When THP-1 cells were challenged only with HKC, detectable levels of IL-23 were not evident. However, challenge by LPS followed by varying concentrations of HKC resulted in increased IL-23 expression by THP-1 cells in HKC dose-dependent manner. Increased expression of IL-17 by PBMC also occurred after stimulation with Candida and LPS. In conclusion, bacterial LPS induces an enhanced immune response to Candida by immune cells, and this occurs through increasing dectin-1 expression