The isotope values of fossil snail shells can be important archives of climate. Here, we present the first carbon (δ13C) and oxygen (δ18O) isotope values of snail shells in interior Alaska to explore changes in vegetation and humidity through the late-glacial period. Snail shell δ13C values were relatively consistent through the late glacial. However, late-glacial shell δ13C values are 2.8‰ higher than those of modern shells. This offset is best explained by the Suess effect and changes in the δ13C values of snail diet. Snail shell δ18O values varied through the late glacial, which can be partially explained by changes in relative humidity (RH). RH during the snail growing period was modeled based on a published flux balance model. Results suggest a dry period toward the beginning of the Bølling–Allerød (~14 ka) followed by two distinct stages of the Younger Dryas, a wetter stage in the early Younger Dryas from 12.9 to 12.3 ka, and subsequent drier stage in the late Younger Dryas between 12.3 and 11.7 ka. The results show that land snail isotopes in high-latitude regions may be used as a supplementary paleoclimate proxy to help clarify complex climate histories, such as those of interior Alaska during the Younger Dryas.

The growing availability of mobile technologies has contributed to an increase in mobile-assisted language learning in which learners can autonomously study a second language (L2) anytime or anywhere (e.g. Kukulska-Hulme, Lee & Norris, 2017; Reinders & Benson, 2017). Research investigating the effectiveness of such study for L2 learning, however, has been limited, especially regarding large-scale commercial L2 learning apps, such as Duolingo. Although one commissioned research study found favorable language learning outcomes (Vesselinov & Grego, 2012), limited independent research has reported issues related to learner persistence, motivation, and program efficacy (Lord, 2015; Nielson, 2011). The current study investigates the semester-long learning experiences and results of nine participants learning Turkish on Duolingo. The participants showed improvement on L2 measures at the end of the study, and results indicate a positive, moderate correlation between the amount of time spent on Duolingo and learning gains. In terms of perceptions of their experiences, the participants generally viewed Duolingo’s flexibility and gamification aspects positively; however, variability in motivation to study and frustration with instructional materials were also expressed.

The geologic setting of the Ziegler Reservoir fossil site is somewhat unusual — the sediments containing the Pleistocene fossils were deposited in a lake on top of a ridge. The lake basin was formed near Snowmass Village, Colorado (USA) when a glacier flowing down Snowmass Creek Valley became thick enough to overtop a low point in the eastern valley wall and entered the head of Brush Creek Valley. When the glacier retreated at about 155–130 ka, near the end of Marine Oxygen Isotope Stage 6, the Brush Creek Valley lobe left behind a moraine that impounded a small alpine lake. The lake was initially ~ 10 m deep and appears to have been highly productive during most of its existence, based on the abundant and exquisitely preserved organic material present in the sediments. Over time, the basin slowly filled with (mostly) eolian sediment such that by ~ 87 ka it contained a marsh or wetland rather than a true lake. Open-water conditions returned briefly between ~ 77 and 55 ka before the impoundment was finally breached to the east, establishing ties with the Brush Creek drainage system and creating an alpine meadow that persisted until historic times.

Studies of terrestrial biotic and environmental dynamics of Marine Oxygen Isotope Stage (MIS) 5, also called the Last Interglacial Period, provide insight into the effects of long-term climate change on Pleistocene ecosystems. In North America, however, there are relatively few fossil sites that definitively date to MIS 5. Even fewer contain multiple ecosystem components (vertebrates, invertebrates, plants) that have been studied in detail, and none are located at high elevation. Thus, our view of North American ecosystems during MIS 5 is, at best, an incomplete composite view, and alpine ecosystems are entirely undocumented.

In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5.

Objective: This study examines the impact of comorbidity of attention-deficit/hyperactivity disorder (ADHD) with disruptive and anxiety disorders in childhood on clinical course and outcome. We consider the relative contribution of each comorbid symptom constellation, and also their interaction, to assess the following questions: (1) Does early comorbidity with conduct disorder (CD) and anxiety disorders define specific developmental trajectories?; (2) Is comorbid anxiety disorders in childhood continuous with anxiety disorders in adolescence?; (3) Does comorbid anxiety disorders mitigate the negative behavioral outcome of youth with ADHD?; and (4) Is there an interaction between comorbid CD and anxiety disorders, when they occur simultaneously, that predicts a different outcome than either comorbid condition alone?

Method: Thirty-two 15- to 18-year-old adolescent males, diagnosed with ADHD between 7 and 11 years of age, were re-evaluated for assessment of adolescent outcome 4.3–9.2 years later. Hierarchical regression analyses were run with each of the eight Child Behavior Checklist and Youth Self-Report problem scales, and the four anxiety symptom subscales of the Multidimensional Anxiety Scale for Children serving as outcome variables.

Results: Findings indicate that comorbid CD at baseline predicteds parent reports of behavior problems in adolescence, while comorbid anxiety disorders in childhood predicted youth reports of anxiety and social problems. Anxiety disorders without CD did not predict poor behavioral outcome. Children with both comorbid CD and anxiety disorder had the highest levels of parent-rated symptoms on follow up. In particular, adolescent social problems were best predicted by the combination of comorbid CD and anxiety disorder in childhood.

Conclusion: These data provide evidence that children with ADHD plus anxiety disorder do in fact have anxiety disorders, and that the combination of anxiety disorder and CD predicts a more rather than less severe course.

Objectives: The aim of this study was to develop a decision support tool to assess the potential benefits and costs of new healthcare interventions.

Methods: The Canadian Partnership Against Cancer (CPAC) commissioned the development of a Cancer Risk Management Model (CRMM)—a computer microsimulation model that simulates individual lives one at a time, from birth to death, taking account of Canadian demographic and labor force characteristics, risk factor exposures, and health histories. Information from all the simulated lives is combined to produce aggregate measures of health outcomes for the population or for particular subpopulations.

Results: The CRMM can project the population health and economic impacts of cancer control programs in Canada and the impacts of major risk factors, cancer prevention, and screening programs and new cancer treatments on population health and costs to the healthcare system. It estimates both the direct costs of medical care, as well as lost earnings and impacts on tax revenues. The lung and colorectal modules are available through the CPAC Web site (www.cancerview.ca/cancerrriskmanagement) to registered users where structured scenarios can be explored for their projected impacts. Advanced users will be able to specify new scenarios or change existing modules by varying input parameters or by accessing open source code. Model development is now being extended to cervical and breast cancers.