INCIDENTAL AND JOINT CONSUMPTION IN RECREATION DEMAND

A theory for analyzing incidental consumption in a single site recreation demand model is presented. We show that incidental consumption on a recreation trip, such as a visit to see friends or a visit to a second recreation site, can be treated as a complementary good and analyzed using conventional theory. We also show that the analysis applies whether the side trips are incidental or joint. In a simple application we find that failing to account for incidental consumption appears to create little bias in valuing recreation sites.Resource /Energy Economics and Policy,

Thermodynamic Studies of [H_(2)Rh(diphosphine)_2]^+ and [HRh(diphosphine)_(2)(CH_(3)CN)]^(2+) Complexes in Acetonitrile

Thermodynamic studies of a series of [H_(2)Rh(PP)_2]^+ and [HRh(PP)_(2)(CH_(3)CN)]^(2+) complexes have been carried out in acetonitrile. Seven different diphosphine (PP) ligands were selected to allow variation of the electronic properties of the ligand substituents, the cone angles, and the natural bite angles (NBAs). Oxidative addition of H_2 to [Rh(PP)_2]^+ complexes is favored by diphosphine ligands with large NBAs, small cone angles, and electron donating substituents, with the NBA being the dominant factor. Large pK_a values for [HRh(PP)_(2)(CH_(3)CN)]^(2+) complexes are favored by small ligand cone angles, small NBAs, and electron donating substituents with the cone angles playing a major role. The hydride donor abilities of [H_(2)Rh(PP)_2]^+ complexes increase as the NBAs decrease, the cone angles decrease, and the electron donor abilities of the substituents increase. These results indicate that if solvent coordination is involved in hydride transfer or proton transfer reactions, the observed trends can be understood in terms of a combination of two different steric effects, NBAs and cone angles, and electron-donor effects of the ligand substituents

Rivers of the Anthropocene Phase 1: A Comparative Study of the Tyne and Ohio River Valleys

poster abstractThe Rivers of the Anthropocene project is an international effort. Our part is an attempt to determine flood frequency and land use by American Indian tribes of the Mississippian Culture along the Ohio River. Methodologically, we will measure the physical and geochemical properties of lacustrine sediments recovered from Hovey Lake, a flood plane lake located on the Ohio River in southwestern Indiana. Sediment cores taken from Hovey Lake are being measured for bulk density and loss-on-ignition tests to determine organic composition by weight. Magnetic susceptibility is also being measured to determine variations in the delivery of terrestrial material (e.g. from flooding/land erosion) to the lake. Land use will be evaluated by measuring variations in the elemental abundance and isotopic composition of nitrogen and organic carbon, which has been used in the past to identify prehistoric land use. Here we present the initial results of our ongoing work, including sedimentological and chronological data. Ultimately, these data will help bring together historical records, geochemical records, and other contributions from scientists around the world in our attempt to better understand mankind’s impact on our environment

Multifractality in stride-to-stride variations reveals that walking involves more movement tuning and adjusting than running

Introduction: The seemingly periodic human gait exhibits stride-to-stride variations as it adapts to the changing task constraints. The optimal movement variability hypothesis (OMVH) states that healthy stride-to-stride variations exhibit “fractality”—a specific temporal structure in consecutive strides that are ordered, stable but also variable, and adaptable. Previous research has primarily focused on a single fractality measure, “monofractality.” However, this measure can vary across time; strideto-stride variations can show “multifractality.” Greater multifractality in stride-tostride variations would highlight the ability to tune and adjust movements more. Methods: We investigated monofractality and multifractality in a cohort of eight healthy adults during self-paced walking and running trials, both on a treadmill and overground. Footfall data were collected through force-sensitive sensors positioned on their heels and feet. We examined the effects of self-paced walking vs. running and treadmill vs. overground locomotion on the measure of monofractality, α-DFA, in addition to the multifractal spectrum width, W, and the asymmetry in the multifractal spectrum, WAsym, of stride interval time series. Results: While the α-DFA was larger than 0.50 for almost all conditions, α-DFA was higher in running and locomoting overground than walking and locomoting on a treadmill. Similarly, W was greater while locomoting overground than on a treadmill, but an opposite trend indicated that W was greater in walking than running. Larger WAsym values in the negative direction suggest that walking exhibits more variation in the persistence of shorter stride intervals than running. However, the ability to tune and adjust movements does not differ between treadmill and overground, although both exhibit more variation in the persistence of shorter stride intervals. Discussion: Hence, greater heterogeneity in shorter than longer stride intervals contributed to greater multifractality in walking compared to running, indicated by larger negative WAsym values. Our results highlight the need to incorporate multifractal methods to test the predictions of the OMVH

Warfare, Demography & Anthropogenic Transformation at Angel Mounds State Historic Site

poster abstractRecent investigations by the Department of Anthropology (IU School of Liberal Arts) and the Glenn A. Black Laboratory of Archaeology (IU-Bloomington) at Angel Mounds have greatly enhanced our understanding of this Mississippian period (AD 1050-1450) village located on the Ohio River in southwestern Indiana. During this timeframe, the Ohio Valley and adjoining regions witnessed an evolution in social complexity with the emergence of small-scale polities, population aggregation in fortified towns, and associated earthwork construction. Angel Mounds was established, grew in prominence, and was eventually abandoned. However, until recently, absolute ages from the site were sparse and the chronology of the town’s settlement, growth and abandonment was poorly understood. Similarly, chronological models for earthwork and fortification construction were non-existent. Our research has revealed that Angel Mounds began as a ceremonial center between AD 1100 and 1300 with few occupants. The residential population at Angel Mounds grew precipitously after AD 1300. By AD 1400, we estimate that as many as 1,000 people lived at Angel Mounds. Concurrently, a series of fortifications were erected at the site to protect the inhabitants from neighboring polities. Meanwhile, earthworks on site were “capped” and abandoned soon thereafter, which may reflect the sociopolitical disintegration of Angel Mounds. Depending on the type of agricultural production and environmental change with the onset of the Little Ice Age, these patterns have important implications for settlement longevities, the historical ecology of land-use, and population estimates in the Eastern Woodlands of North America by AD 1500. With support from the Nation Science Foundation, the next three years of investigations at Angel Mounds will continue to focus on population dynamics, earthwork construction and use, anthropogenic transformation of the landscape, and environmental change during the Medieval Warm and Little Ice Age

Cognitive flexibility training for chronic pain: A randomized clinical study

INTRODUCTION: Previous studies suggest an association between cognitive flexibility and development of chronic pain after surgery. It is not known whether cognitive flexibility can be improved in patients with chronic pain. OBJECTIVES: This study tested whether a neurocognitive training program results in improved cognitive flexibility and pain in patients with chronic pain. METHODS: We conducted a single-center, prospective, randomized study investigating 5-week daily neurocognitive training in patients with chronic pain. Participants (n = 145) were randomized into neurocognitive training or care as usual, and they completed assessments at baseline, posttreatment, and 3 months. The treatment group was asked to spend 35 minutes daily completing a program with tasks on cognitive flexibility, memory, attention, and speed. The primary outcome was performance on the neurocognitive performance test (NCPT). Secondary outcomes included levels of pain interference and severity. RESULTS: At 5 weeks, the treatment group showed greater improvements on NCPT compared with the control group ( CONCLUSIONS: Outcomes suggest that using neurocognitive training to modify cognitive flexibility in patients with chronic pain may improve pain severity. This study provided effect size estimates to inform sample size calculations for randomized controlled trials to test the effectiveness of neurocognitive interventions for the prevention and treatment of chronic pain

Integrative analysis of genomic and exposomic influences on youth mental health

Background: Understanding complex influences on mental health problems in young people is needed to inform early prevention strategies. Both genetic and environmental factors are known to influence youth mental health, but a more comprehensive picture of their interplay, including wide-ranging environmental exposures – that is, the exposome – is needed. We perform an integrative analysis of genomic and exposomic data in relation to internalizing and externalizing symptoms in a cohort of 4,314 unrelated youth from the Adolescent Brain and Cognitive Development (ABCD) Study. / Methods: Using novel GREML-based approaches, we model the variance in internalizing and externalizing symptoms explained by additive and interactive influences from the genome (G) and modeled exposome (E) consisting of up to 133 variables at the family, peer, school, neighborhood, life event, and broader environmental levels, including genome-by-exposome (G × E) and exposome-by-exposome (E × E) effects. / Results: A best-fitting integrative model with G, E, and G × E components explained 35% and 63% of variance in youth internalizing and externalizing symptoms, respectively. Youth in the top quintile of model-predicted risk accounted for the majority of individuals with clinically elevated symptoms at follow-up (60% for internalizing; 72% for externalizing). Of note, different domains of environmental exposures were most impactful for internalizing (life events) and externalizing (contextual including family, school, and peer-level factors) symptoms. In addition, variance explained by G × E contributions was substantially larger for externalizing (33%) than internalizing (13%) symptoms. / Conclusions: Advanced statistical genetic methods in a longitudinal cohort of youth can be leveraged to address fundamental questions about the role of ‘nature and nurture’ in developmental psychopathology

Using GPS-enabled cell phones to track the travel patterns of adolescents

<p>Abstract</p> <p>Background</p> <p>Few tools exist to directly measure the microsocial and physical environments of adolescents in circumstances where participatory observation is not practical or ethical. Yet measuring these environments is important as they are significantly associated with adolescent health-risk. For example, health-related behaviors such as cigarette smoking often occur in specific places where smoking may be relatively surreptitious.</p> <p>Results</p> <p>We assessed the feasibility of using GPS-enabled cell phones to track adolescent travel patterns and gather daily diary data. We enrolled 15 adolescent women from a clinic-based setting and asked them to carry the phones for 1 week. We found that these phones can accurately and reliably track participant locations, as well as record diary information on adolescent behaviors. Participants had variable paths extending beyond their immediate neighborhoods, and denied that GPS-tracking influenced their activity.</p> <p>Conclusion</p> <p>GPS-enabled cell phones offer a feasible and, in many ways, ideal modality of monitoring the location and travel patterns of adolescents. In addition, cell phones allow space- and time-specific interaction, probing, and intervention which significantly extends both research and health promotion beyond a clinical setting. Future studies can employ GPS-enabled cell phones to better understand adolescent environments, how they are associated with health-risk behaviors, and perhaps intervene to change health behavior.</p

On the value of threshold signatures

Threshold signature schemes are examples of threshold cryptosystems, as introduced by Desmedt, [4]. The purpose of this paper is to present a rather simple alternative to threshold signatures which raises questions about the value of such schemes, at least when applied to the mobile agent scenario