Late Holocene Lake-Level Fluctuations in Walker Lake, Nevada, USA

alker Lake, a hydrologically closed, saline, and alkaline lake, is situated along the western margin of the Great Basin in Nevada of the western United States. Analyses of the magnetic susceptibility (χ), total inorganic carbon (TIC), and oxygen isotopic composition (δ18O) of carbonate sediments including ostracode shells (Limnocythere ceriotuberosa) from Walker Lake allow us to extend the sediment record of lake-level fluctuations back to 2700 years B.P. There are approximately five major stages over the course of the late Holocene hydrologic evolution in Walker Lake: an early lowstand (\u3e 2400 years B.P.), a lake-filling period (∼ 2400 to ∼ 1000 years B.P.), a lake-level lowering period during the Medieval Warm Period (MWP) (∼ 1000 to ∼ 600 years B.P.), a relatively wet period (∼ 600 to ∼ 100 years B.P.), and the anthropogenically induced lake-level lowering period (\u3c 100 years B.P.). The most pronounced lowstand of Walker Lake occurred at ∼ 2400 years B.P., as indicated by the relatively high values of δ18O. This is generally in agreement with the previous lower resolution paleoclimate results from Walker Lake, but contrasts with the sediment records from adjacent Pyramid Lake and Siesta Lake. The pronounced lowstand suggests that the Walker River that fills Walker Lake may have partially diverted into the Carson Sink through the Adrian paleochannel between 2700 to 1400 years B.P

Methodology for Selection, Sequencing, and Deployment of Activities in a Capstone Design Course Using the Tidee Web-Based Assessment System

Assessment of design process, design products, team process, and professional practice are natural fits in an engineering capstone design course. In order for instructors and students to fully experience the value of capstone course assessment activities, the activities must not only be carefully developed but must also be deployed in an appropriate manner. Course designers must choose an optimal set of assignments based on local needs, while balancing time intensive design project activities with professional growth experiences. Instructors must facilitate the complete cycle of usage of a single assignment in order to ensure that the value is understood before and after completion of the assessment. This paper introduces guidelines for achieving effectiveness in selecting, timing, and sequencing assessment activities, preparing for activity deployment, and implementing a facilitation plan. Additionally this paper reports on the feedback from students and faculty using the system that highlights the importance of naturalistically integrating assessment

Capstone Design Hub: Building the Capstone Design Community

Capstone design courses are common across engineering programs nationwide. Yet, many departments and programs rely on one faculty member or a small handful of faculty members to teach their capstone design course. As a result these faculty members find themselves isolated, with limited mechanisms for sharing ideas and networking with peers who have similar responsibilities and concerns. This paper reports on the ongoing efforts to support the broader capstone design community through the development of the Capstone Design Hub (CDHub) as a web resource for capstone design programs. The features and structure of the CDHub are being developed through capstone faculty input, including results from a survey of the capstone community. To build awareness of the CDHub as well as to solicit additional feedback from the community, this paper describes development of the hub to meet community needs, initial population of the hub with resources focused on communication, and plans for continued expansion of the hub. © 2012 American Society for Engineering Education

Minnesota’s County Land Management A Unique Ownership Providing Diverse Benefits

Minneapolis: Dovetail Partners.This report concerns public and private forests in northeastern Minnesota. It does not specifically deal with water resources except to note the following: “Ideally, forest management for restoration, forest health, wildlife habitat, and biodiversity benefits should be continued even when market prices are low. Delaying management because of poor market conditions may result in declines in forest health due to insect or disease issues being left untreated or other changes that can diminish water quality protections and important wildlife habitats. Delayed harvests and associated silvicultural treatments can also negatively impact recreation and other social benefits benefits.” Also, under the topic of water quality, the report advocates utilizing improved inventory data (forest cover types, species, age, native plant communities, soils, etc.) to evaluate current conditions in known impaired watersheds and develop long-term plans. Other key points are extracted and summarized below. “Minnesota is among a small number of states that have county managed forest land. This report explores the history and current contribution of Minnesota’s county-managed forest lands, including the diverse social, economic and environmental benefits they provide. "Minnesota’s “county forests” originated during the 1930s. During the era of the Great Depression, the state was challenged with the consequences of unsustainable farming practices, cut-and-run logging, bankrupt homesteads and devastating wildfires. Thousands of acres of land became tax delinquent as owners could not, or for a variety of reasons would not, pay their taxes. These lands were labeled "worthless” and became the "lands nobody wanted." In 1935, in an attempt to return the tax delinquent acres to private ownership, the Minnesota Legislature provided for forfeiture of these lands to local counties, thereby enabling their resale to others. By this time, about eight million acres of tax-forfeited land had accumulated. Delinquency and subsequent forfeiture continued at a high level into the 1960s. As the demand for land remained low and many of the acres were not re-sold, the land continued to be the responsibility of the local county governments. Over time, the counties began to recognize opportunities to care for these lands in ways that could rebuild the soils, restore forest habitats, enhance local communities and create long-term economic returns. Counties found they could manage the lands to grow trees on a sustained-yield basis and the returns from this management could improve the environment and also provide jobs, revenues to meet public needs, and other benefits. In 1979, the Minnesota Legislature enacted "Payment In Lieu of Tax (PILT) Legislation" that encouraged retention of the tax-forfeited land by the local public land managers. The law provided compensation to local taxing districts (i.e., counties) for retaining land that represented a loss of tax base. These payments remain important for sustaining the needs of local communities and ensuring continual stewardship of natural resources. Counties do not share a uniform plan or prescription for management of forests. Each county manages its woodlands independently. Local interests, including the common use of citizen advisory committees, inform management decisions and county staff and boards administer the lands. In recent years, county land departments have provided leadership in several areas linked to responsible forest management. These include third-party forest certification, forest-based carbon offset opportunities, motorized recreation management, and forest inventory needs. Most of the benefits and services of county lands are not easily quantified and many are provided at no direct cost, which makes estimating their value difficult. However, related research has explored the potential value of these types of benefits. 98% of the lands each year are providing undisturbed habitat, water quality and recreation benefits. Minnesota’s county forest lands, unwanted in the 1930s, now provide unique opportunities to address local community needs, contribute to resolution of emerging issues, and demonstrate responsible forestry. County land managers are currently challenged by a number of significant threats, including invasive species, forest health concerns, and reduced markets. At the same time, the management of county forests is subjected to political pressures, shrinking local and state budgets, and competing interests. Minnesota is one of a few states that has county-managed lands within the public land category. These county lands can be described as Minnesota’s “community-forests” due to the important social, economic and ecological services they provide as public lands under local control. The county-managed lands provide a unique type of land ownership within the context of public forest lands in the state. To ensure the delivery of the services and benefits of these lands for future generations continued investment and statewide commitment to their responsible care and management is required.”Fernholz, Kathryn; Bowyer, Jim; Howe, Jeff; Bratkovich, Steve; Frank, Matt. (2004). Minnesota’s County Land Management A Unique Ownership Providing Diverse Benefits. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/189289

Crowdsourcing good landmarks for in-vehicle navigation systems

Augmenting navigation systems with landmarks has been posited as a method of improving the effectiveness of the technology and enhancing drivers’ engagement with the environment. However, good navigational landmarks are both laborious to collect and difficult to define. This research aimed to devise a game concept, which could be played by passengers in cars, and would collect useful landmark data as a by-product. The paper describes how a virtual graffiti tagging game concept was created and tested during on-road trials with 38 participants. The data collected in the road trials were then validated using a survey, in which 100 respondents assessed the quality of the landmarks collected and their potential for reuse in navigation applications. Players of the game displayed a consensus in choosing where to place their graffiti tags with over 30% of players selecting the same object to tag in 10 of the 12 locations. Furthermore, significant correlation was found between how highly landmarks were rated in the survey and how frequently they were tagged during the game. The research provides evidence that using crowdsourcing games to collect landmarks does not require large numbers of people, or extensive coverage of an area, to produce suitable candidate landmarks for navigation

Weathering fluxes and sediment provenance on the SW Scottish shelf during the last deglaciation

The reconstruction of past ice sheet dynamics can shed a light on long-term ice stream activity, and in turn provide constraints on the response of modern ice sheets to climate change. The Hebrides Ice Stream (HIS) flowed across part of the western Scottish shelf to the shelf-break during the last glacial cycle and drained a large portion of the northern sector of the British Irish-Ice Sheet. To investigate the deglacial dynamics of the HIS following the Last Glacial Maximum, lead (Pb) isotope records were extracted from the FeMn oxyhydroxide and detrital fractions of recovered laminated glacimarine mud sequences to monitor the changing activity of HIS during its retreat. These provide timing and some source information of glacially weathered inputs to the marine environment. The FeMn oxyhydroxide fraction in the samples is dominated by allochthonous particles (pre-formed) and shows a marked decrease from radiogenic (≤ 20.05 206Pb/204Pb) at ~ 21 cal ka BP to less radiogenic Pb isotope compositions (~ 19.48) towards the Windermere Interstadial (15.4–13 ka). This decrease represents a reduction in the flux of subglacially-derived radiogenic Pb to the continental shelf is interpreted as being associated with the break-up of the ice-stream in western Scotland around that time. The Pb, Sr and Nd isotopic signatures of the detrital fraction indicate a preponderance of Moine-sourced fine sediments (originated from the NW Highlands) in the core locations from ~ 21 to 15 cal ka BP (Dimlington Stadial - Windermere Interstadial), most likely dictated by the orientation of ice flow, tidal and oceanic current directions and sediment delivery. In contrast, ice rafted debris in a ~ 21 cal ka BP old basal diamicton contains volcanic-derived material, suggesting different provenance for different grain sizes. The FeMn oxyhydroxide 208Pb/204Pb ratio shows an unusual inversion relative to the other Pb isotope ratios, and is attributed to the introduction of secondary weathering phases from a source with contrasting 208Pb/204Pb but similar 206Pb/204Pb and 207Pb/204Pb. In the detrital fraction, the inversions are constrained to periodic spikes, which may indicate an increased contribution from a high Th/U source, potentially the neighbouring Archaean amphibolitic Lewisian basement in the Outer Hebrides. This study demonstrates how geochemical investigation on continental shelves can be used to constrain the timing, activity and flow sources of palaeo-ice streams

Exercise for reducing fear of falling in older people living in the community: Cochrane systematic review and meta-analysis

Objective: To determine the effect of exercise interventions on fear of falling in community-living people aged ≥65 years. Design: Systematic review and meta-analysis. Bibliographic databases, trial registers and other sources were searched for randomised or quasi-randomised trials. Data were independently extracted by pairs of reviewers using a standard form. Results: Thirty trials (2878 participants) reported 36 interventions (Tai Chi and yoga (n=9); balance training (n=19); strength and resistance training (n=8)). The risk of bias was low in few trials. Most studies were from high income countries (Australia=8, USA=7). Intervention periods (26 weeks=7) and exercise frequency (1-3 times/week=32; ≥4 times/week=4) varied between studies. Fear of falling was measured by single-item questions (7) and scales measuring falls efficacy (14), balance confidence (9) and concern or worry about falling (2). Meta-analyses showed a small to moderate effect of exercise interventions on reducing fear of falling immediately post intervention (standardised mean difference (SMD) 0.37, 95% CI 0.18, 0.56; 24 studies; low quality evidence). There was a small, but not statistically significant effect in the longer term (<6 months (SMD 0.17, 95% CI -0.05, 0.38 (four studies) and ≥ 6 months post intervention SMD 0.20, 95% CI -0.01, 0.41 (three studies)). Conclusions: Exercise interventions probably reduce fear of falling to a small to moderate degree immediately post-intervention in community-living older people. The high risk of bias in most included trials suggests findings should be interpreted with caution. High quality trials are needed to strengthen the evidence base in this area

A Fiji multi-coral δ¹⁸O composite approach to obtaining a more accurate reconstruction of the last two-centuries of the ocean-climate variability...

The limited availability of oceanographic data in the tropical Pacific Ocean prior to the satellite era makes coral-based climate reconstructions a key tool for extending the instrumental record back in time, thereby providing a much needed test for climate models and projections. We have generated a unique regional network consisting of five Porites coral δ¹⁸O time series from different locations in the Fijian archipelago. Our results indicate that using a minimum of three Porites coral δ¹⁸O records from Fiji is statistically sufficient to obtain a reliable signal for climate reconstruction, and that application of an approach used in tree ring studies is a suitable tool to determine this number. The coral δ¹⁸O composite indicates that while sea surface temperature (SST) variability is the primary driver of seasonal δ¹⁸O variability in these Fiji corals, annual average coral δ¹⁸O is more closely correlated to sea surface salinity (SSS) as previously reported. Our results highlight the importance of water mass advection in controlling Fiji coral δ¹⁸O and salinity variability at interannual and decadal time scales despite being located in the heavy rainfall region of the South Pacific Convergence Zone (SPCZ). The Fiji δ¹⁸O composite presents a secular freshening and warming trend since the 1850s coupled with changes in both interannual (IA) and decadal/interdecadal (D/I) variance. The changes in IA and D/I variance suggest a re-organization of climatic variability in the SPCZ region beginning in the late 1800s to period of a more dominant interannual variability, which could correspond to a southeast expansion of the SPCZ

The epigenetic clock and physical development during childhood and adolescence:longitudinal analysis from a UK birth cohort

Additional file 4: S7. Pairwise genetic distance matrix for Cytochrome c oxidase subunit 1 (COI)