57 research outputs found

    Homelessness and nonrecreational camping on national forests and grasslands in the United States: Law enforcement perspectives and regional trends

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    National forest law enforcement officers regularly encounter nonrecreational campers whose tenure exceeds established stay limits (generally 2 weeks). Some long-term occupants are homeless and seek use of the forest as a temporary or long-term residence. Long-term nonrecreational campers present myriad concerns for forest officials, who seek to balance public access and resource conservation. In addition to biophysical impacts because of waste, disposal of chemicals, soil compaction, and damage to vegetation, nonrecreational campers can alter the social environment being shared with other forest visitors. For this exploratory study, US Forest Service law enforcement officers (n = 290) were surveyed to assess officer perceptions of the frequency of encounters, trends, and types of nonrecreational campers. We provide a descriptive summary of major findings and point out regional variations and trends. Officers perceive regional variations in the frequency of encounters with nonrecreational or homeless campers as well as types of campers encountered

    If you build it, will they come?

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    National forests have a wealth of natural amenities that attract over 175 million recreational visitors a year. Although natural amenities draw visitors to national forests, many of the recreational activities that they engage in require built amenities, such as roads, campgrounds, boat ramps, and trails. We estimate regression models of the effect of two common built amenities—campgrounds and picnic areas—on national-forest visitation controlling for natural amenities and accounting for the endogenous relationship between visitation and built amenities. We found that campgrounds and picnic areas are significantly and positively correlated with visitation

    Making and Breaking Trust in Forest Collaborative Groups

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    There has been a recent increase in use of an organized, forest ‘collaborative’ group approach for multi-stakeholder input on federal forestlands in the U.S. West. This approach relies on the creation of shared trust to achieve social agreement. Yet growing critiques suggest a lack of trust in the U.S. Forest Service [Forest Service], between stakeholders, and the collaborative process itself. We conducted three comparative case studies of established forest collaborative groups in Oregon, Washington, and Idaho to ask how trust is created and damaged or broken in this context. We found multiple, interlinked dimensions to trust, including significant reliance on procedural trust, trust of ‘in-groups’ who shared norms for conduct, and distrust of new participants. We also found that trust or distrust in the Forest Service affected other trust and process dynamics within groups. Our research offers new insights into the functions and limitations of a collaborative approach that is increasingly central to federal forest governance; and new empirical knowledge toward recent theoretical developments about trust in natural resource collaboration

    Mitochondrial Fragmentation Is Involved in Methamphetamine-Induced Cell Death in Rat Hippocampal Neural Progenitor Cells

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    Methamphetamine (METH) induces neurodegeneration through damage and apoptosis of dopaminergic nerve terminals and striatal cells, presumably via cross-talk between the endoplasmic reticulum and mitochondria-dependent death cascades. However, the effects of METH on neural progenitor cells (NPC), an important reservoir for replacing neurons and glia during development and injury, remain elusive. Using a rat hippocampal NPC (rhNPC) culture, we characterized the METH-induced mitochondrial fragmentation, apoptosis, and its related signaling mechanism through immunocytochemistry, flow cytometry, and Western blotting. We observed that METH induced rhNPC mitochondrial fragmentation, apoptosis, and inhibited cell proliferation. The mitochondrial fission protein dynamin-related protein 1 (Drp1) and reactive oxygen species (ROS), but not calcium (Ca2+) influx, were involved in the regulation of METH-induced mitochondrial fragmentation. Furthermore, our results indicated that dysregulation of ROS contributed to the oligomerization and translocation of Drp1, resulting in mitochondrial fragmentation in rhNPC. Taken together, our data demonstrate that METH-mediated ROS generation results in the dysregulation of Drp1, which leads to mitochondrial fragmentation and subsequent apoptosis in rhNPC. This provides a potential mechanism for METH-related neurodegenerative disorders, and also provides insight into therapeutic strategies for the neurodegenerative effects of METH

    Effect of personal exposure to black carbon on changes in allergic asthma gene methylation measured 5 days later in urban children: importance of allergic sensitization

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    Background Asthma gene DNA methylation may underlie the effects of air pollution on airway inflammation. However, the temporality and individual susceptibility to environmental epigenetic regulation of asthma has not been fully elucidated. Our objective was to determine the timeline of black carbon (BC) exposure, measured by personal sampling, on DNA methylation of allergic asthma genes 5 days later to capture usual weather variations and differences related to changes in behavior and activities. We also sought to determine how methylation may vary by seroatopy and cockroach sensitization and by elevated fractional exhaled nitric oxide (FeNO). Methods Personal BC levels were measured during two 24-h periods over a 6-day sampling period in 163 New York City children (age 9–14 years), repeated 6 months later. During home visits, buccal cells were collected as noninvasive surrogates for lower airway epithelial cells and FeNO measured as an indicator of airway inflammation. CpG promoter loci of allergic asthma genes (e.g., interleukin 4 (IL4), interferon gamma (IFNγ), inducible nitric oxide synthase (NOS2A)), arginase 2 (ARG2)) were pyrosequenced at the start and end of each sampling period. Results Higher levels of BC were associated with lower methylation of IL4 promoter CpG−48 5 days later. The magnitude of association between BC exposure and demethylation of IL4 CpG−48 and NOS2A CpG+5099 measured 5 days later appeared to be greater among seroatopic children, especially those sensitized to cockroach allergens (RR [95% CI] 0.55 [0.37–0.82] and 0.67 [0.45–0.98] for IL4 CpG−48 and NOS2A CpG+5099, respectively), compared to non-sensitized children (RR [95% CI] 0.87 [0.65–1.17] and 0.95 [0.69–1.33] for IL4 CpG−48 and NOS2A CpG+5099, respectively); however, the difference was not statistically different. In multivariable linear regression models, lower DNA methylation of IL4 CpG−48 and NOS2A CpG+5099 were associated with increased FeNO. Conclusions Our results suggest that exposure to BC may exert asthma proinflammatory gene demethylation 5 days later that in turn may link to airway inflammation. Our results further suggest that seroatopic children, especially those sensitized to cockroach allergens, may be more susceptible to the effect of acute BC exposure on epigenetic changes

    Formulation, stabilisation and encapsulation of bacteriophage for phage therapy

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    Against a backdrop of global antibiotic resistance and increasing awareness of the importance of the human microbiota, there has been resurgent interest in the potential use of bacteriophages for therapeutic purposes, known as phage therapy. A number of phage therapy phase I and II clinical trials have concluded, and shown phages don’t present significant adverse safety concerns. These clinical trials used simple phage suspensions without any formulation and phage stability was of secondary concern. Phages have a limited stability in solution, and undergo a significant drop in phage titre during processing and storage which is unacceptable if phages are to become regulated pharmaceuticals, where stable dosage and well defined pharmacokinetics and pharmacodynamics are de rigueur. Animal studies have shown that the efficacy of phage therapy outcomes depend on the phage concentration (i.e. the dose) delivered at the site of infection, and their ability to target and kill bacteria, arresting bacterial growth and clearing the infection. In addition, in vitro and animal studies have shown the importance of using phage cocktails rather than single phage preparations to achieve better therapy outcomes. The in vivo reduction of phage concentration due to interactions with host antibodies or other clearance mechanisms may necessitate repeated dosing of phages, or sustained release approaches. Modelling of phage-bacterium population dynamics reinforces these points. Surprisingly little attention has been devoted to the effect of formulation on phage therapy outcomes, given the need for phage cocktails, where each phage within a cocktail may require significantly different formulation to retain a high enough infective dose. This review firstly looks at the clinical needs and challenges (informed through a review of key animal studies evaluating phage therapy) associated with treatment of acute and chronic infections and the drivers for phage encapsulation. An important driver for formulation and encapsulation is shelf life and storage of phage to ensure reproducible dosages. Other drivers include formulation of phage for encapsulation in micro- and nanoparticles for effective delivery, encapsulation in stimuli responsive systems for triggered controlled or sustained release at the targeted site of infection. Encapsulation of phage (e.g. in liposomes) may also be used to increase the circulation time of phage for treating systemic infections, for prophylactic treatment or to treat intracellular infections. We then proceed to document approaches used in the published literature on the formulation and stabilisation of phage for storage and encapsulation of bacteriophage in micro- and nanostructured materials using freeze drying (lyophilization), spray drying, in emulsions e.g. ointments, polymeric microparticles, nanoparticles and liposomes. As phage therapy moves forward towards Phase III clinical trials, the review concludes by looking at promising new approaches for micro- and nanoencapsulation of phages and how these may address gaps in the field

    Tourism and transformations in the Alaska frontier: A study of tourism growth and its effects on three southeast Alaska communities

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    Tourism is one of the world\u27s largest and fastest growing industries. Developing regions seek to expand their economic base through tourism, with endorsement of states and multilateral institutions. Meanwhile, tourism, as a product and process of globalization, can transform host communities and natural resources, affecting local livelihoods and lifestyles. This dissertation utilizes a comparative case study approach to understand the role of tourism in shaping communities, economies, and natural resources in three rural Alaska sites. Sites selected were similar in size, demographic composition and economic history, but varied in their level of tourism involvement. Stakeholder analysis was employed to disaggregate the involvement of various social actors. The purpose of this study was two-fold: (a) to understand how multi-level stakeholders engaged in the process of tourism development within host communities; (b) to investigate how tourism impacts were distributed among various stakeholders. Dynamic relations among local and non-local stakeholders building a tourism economy were explored. Tourism impacts were examined among these stakeholders and other social groups to differentiate tourism beneficiaries and those bearing the burden of tourism. Stakeholder analysis revealed that tourism was introduced to host communities from both local and non-local institutions. Comparative case analysis revealed that corporate investment in tourism increased the scale of the tourism enterprise and facilitated global integration. As tourism expanded, non-local corporations played a greater role in the local economy. Results also showed that tourism impacts were magnified when local patterns of resource use were altered. Tourism resulted in conflicts among stakeholders competing for shared resources, with fishermen and recreation users bearing the brunt of tourism. Tourism provided clear economic incentives for businesses and local governments, but few clear benefits for workers. Finally, the socio-cultural effects of tourism were widely shared, with particular implications for Alaska Natives needing to preserve cultural resources

    If you build it, will they come?

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    National forests have a wealth of natural amenities that attract over 175 million recreational visitors a year. Although natural amenities draw visitors to national forests, many of the recreational activities that they engage in require built amenities, such as roads, campgrounds, boat ramps, and trails. We estimate regression models of the effect of two common built amenities—campgrounds and picnic areas—on national-forest visitation controlling for natural amenities and accounting for the endogenous relationship between visitation and built amenities. We found that campgrounds and picnic areas are significantly and positively correlated with visitation
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