The composition of particulates in Lake Michigan using S.E.M. and light microscope techniques

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24549/1/0000829.pd

Adaptations in a hierarchical food web of southeastern Lake Michigan

Two issues in ecological network theory are: (1) how to construct an ecological network model and (2) how do entire networks (as opposed to individual species) adapt to changing conditions? We present a novel method for constructing an ecological network model for the food web of southeastern Lake Michigan (USA) and we identify changes in key system properties that are large relative to their uncertainty as this ecological network adapts fromone time point to a second time point in response to multiple perturbations. To construct our foodweb for southeastern Lake Michigan,we followed the list of seven recommendations outlined in Cohen et al. [Cohen, J.E., et al., 1993.Improving foodwebs. Ecology 74, 252–258] for improving food webs. We explored two inter-related extensions of hierarchical system theory with our food web; the first one was that subsystems react to perturbations independently in the short-term and the second onewas that a system’s properties change at a slower rate than its subsystems’ properties. We used Shannon’s equations to provide quantitative versions of the basic food web properties: number of prey, number of predators, number of feeding links, and connectance (or density).We then compared these properties between the two time-periods by developing distributions of each property for each time period that took uncertainty about the property into account.We compared these distributions, and concluded that non-overlapping distributions indicated changes in these properties that were large relative to their uncertainty. Two subsystems were identified within our food web system structure (p \u3c 0.001). One subsystem had more non-overlapping distributions in food web properties between Time 1 and Time 2 than the other subsystem. The overall system had all overlapping distributions in food web properties between Time 1 and Time 2. These results supported both extensions of hierarchical systems theory. Interestingly, the subsystemwithmore non-overlapping distributions in foodweb propertieswas the subsystemthat contained primarily benthic taxa, contrary to expectations that the identifiedmajor perturbations (lower phosphorous inputs and invasive species) would more greatly affect the subsystem containing primarily pelagic taxa. Future food-web research shouldemploy rigorous statistical analysis and incorporate uncertainty in food web properties for a better understanding of how ecological networks adapt

Contributions and perspectives of Indigenous Peoples to the study of mercury in the Arctic

Arctic Indigenous Peoples are among themost exposed humanswhen it comes to foodbornemercury (Hg). In response, Hgmonitoring and research have been on-going in the circumpolar Arctic since about 1991; this work has beenmainly possible through the involvement of Arctic Indigenous Peoples. The present overview was initially conducted in the context of a broader assessment of Hg research organized by the Arctic Monitoring and Assessment Programme. This article provides examples of Indigenous Peoples' contributions to Hg monitoring and research in the Arctic, and discusses approaches that could be used, and improved upon, when carrying out future activities. Over 40 mercury projects conducted with/by Indigenous Peoples are identified for different circumpolar regions including the U.S., Canada, Greenland, Sweden, Finland, and Russia as well as instances where Indigenous Knowledge contributed to the understanding of Hg contamination in the Arctic. Perspectives and visions of future Hg research as well as recommendations are presented. The establishment of collaborative processes and partnership/co-production approaches with scientists and Indigenous Peoples, using good communication practices and transparency in research activities, are key to the success of research and monitoring activities in the Arctic. Sustainable funding for community-driven monitoring and research programs in Arctic countries would be beneficial and assist in developing more research/monitoring capacity and would promote a more holistic approach to understanding Hg in the Arctic. These activities should be well connected to circumpolar/international initiatives to ensure broader availability of the information and uptake in policy development

Mesh size and collection characteristics of 50-cm diameter conical plankton nets

This paper compares collection characteristics of #2-(363 µm), #10-(156 µm), and #20-(76 µm) mesh conical plankton nets: dimensions were 50-cm diameter by 1.6-m long. The #2-mesh net severely underestimated the abundances of Lake Michigan copepods and cladocerans with the exception of the largest species ( Limnocalanus macrurus ). Zooplankton abundance estimates were more similar for the #10- and #20-mesh nets collections. Nauplii, however, were severely undersampled by the #10-mesh net with abundance estimates approximately 8 to 12 times lower than for the #20-mesh net collections. Most other larger zooplankton were 50% more abundant in the 20-mesh net collections than in the #10-mesh net collections: such consistent differences occurred despite large variations in taxa size. This indicates that a sampling bias occurred other than the loss of zooplankton through the meshes of the #10 net. We hypothesize that, by incorrectly locating the flowmeter in the mouth of the plankton net, we underestimated the volume of water filtered by the easily-clogged #20-mesh net and therefore overestimated taxa abundances. We conclude that the #10-mesh net provided accurate estimates of microcrustacean zooplankton abundances except for nauplii. The #10-mesh net used in our study had a filtration area ratio of 3.06 and operated at a calculated average filtration efficiency of 98%. The #20-mesh net had a filtration area ratio of 1.86 and operated at calculated average filtration efficiencies ranging from 64.7% (41.7 m station) to 79.6% (6.3 m station). Calculations are presented which show how the filtration efficiencies of the nets used in our study could be improved by net redesign.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42868/1/10750_2004_Article_BF00032095.pd

A statistical analysis of subsampling and an evaluation of the Folsom plankton splitter

Subsampling techniques are important for the determination of precise plankton density estimates. A binomial model of random subsampling, and its Poisson extension, were developed for the purpose of evaluating the performance of compartment-type plankton subsamplers. Two approaches were used to assess the performance of the Folsom plankton splitter on an extensive series of nearshore Lake Michigan crustacean zooplankton samples collected between 1974 and 1979. First, Folsom subsamples were observed to be significantly (p < 0.05) more variable than expected from the random model of subsampling. Second, a random effects ANOVA model was used to compare fractions of the total variance in density estimates that were attributable to subsampling and sampling phases of a specially designed study. Departures from randomness in subsampling were sufficiently small that an analysis of optimal allocation of effort between subsampling and sampling phases, based on the ANOVA model, indicated that only one to three subsamples needed to be examined per sample.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42920/1/10750_2004_Article_BF00016403.pd

Contributions and perspectives of Indigenous Peoples to the study of mercury in the Arctic

Arctic Indigenous Peoples are among the most exposed humans when it comes to foodborne mercury (Hg). In response, Hg monitoring and research have been on-going in the circumpolar Arctic since about 1991; this work has been mainly possible through the involvement of Arctic Indigenous Peoples. The present overview was initially conducted in the context of a broader assessment of Hg research organized by the Arctic Monitoring and Assessment Programme. This article provides examples of Indigenous Peoples' contributions to Hg monitoring and research in the Arctic, and discusses approaches that could be used, and improved upon, when carrying out future activities. Over 40 mercury projects conducted with/by Indigenous Peoples are identified for different circumpolar regions including the U.S., Canada, Greenland, Sweden, Finland, and Russia as well as instances where Indigenous Knowledge contributed to the understanding of Hg contamination in the Arctic. Perspectives and visions of future Hg research as well as recommendations are presented. The establishment of collaborative processes and partnership/co-production approaches with scientists and Indigenous Peoples, using good communication practices and transparency in research activities, are key to the success of research and monitoring activities in the Arctic. Sustainable funding for community-driven monitoring and research programs in Arctic countries would be beneficial and assist in developing more research/ monitoring capacity and would promote a more holistic approach to understanding Hg in the Arctic. These activities should be well connected to circumpolar/international initiatives to ensure broader availability of the information and uptake in policy development

Implications of Training in Incremental Theories of Intelligence for Undergraduate Statistics Students

This chapter documents the effects of training in incremental theories of intelligence on students in introductory statistics courses at a liberal arts university in the US. Incremental theories of intelligence examine the beliefs individuals hold of knowledge and how it is attained. An individual with an incremental theory of intelligence believes that intelligence can be developed. The research examined differences by gender in mastery of statistics and attitudes toward statistics for students who received growth mind-set training. A pre-test, post-test design utilised the Students’ Attitudes Toward Statistics© instrument and the Comprehensive Assessment of Outcomes in a first Statistics course. An ANCOVA revealed that females gained more than males on their value of statistics (F(1, 63) 9.40, MSE 3.79, p .003, η2 P 0.134) and decreased less for effort expended to learn statistics (F(1, 63) 4.41, MSE 4.07, p .040, η2 P 0.067). Females also gained mastery of statistical concepts at a greater rate (F(1, 63) 5.30, MSE 0.06, p .025, η2 P 0.080) indicating a possible path to alleviate the under-representation of females in STEM

A Clinical Trial of the Effects of Dietary Patterns on Blood Pressure

BACKGROUND: It is known that obesity, sodium intake, and alcohol consumption factors influence blood pressure. In this clinical trial, Dietary Approaches to Stop Hypertension, we assessed the effects of dietary patterns on blood pressure. METHODS: We enrolled 459 adults with systolic blood pressures of less than 160 mm Hg and diastolic blood pressures of 80 to 95 mm Hg. For three weeks, the subjects were fed a control diet that was low in fruits, vegetables, and dairy products, with a fat content typical of the average diet in the United States. They were then randomly assigned to receive for eight weeks the control diet, a diet rich in fruits and vegetables, or a "combination" diet rich in fruits, vegetables, and low-fat dairy products and with reduced saturated and total fat. Sodium intake and body weight were maintained at constant levels. RESULTS: At base line, the mean (+/-SD) systolic and diastolic blood pressures were 131.3+/-10.8 mm Hg and 84.7+/-4.7 mm Hg, respectively. The combination diet reduced systolic and diastolic blood pressure by 5.5 and 3.0 mm Hg more, respectively, than the control diet (P or =140 mm Hg; diastolic pressure, > or =90 mm Hg; or both), the combination diet reduced systolic and diastolic blood pressure by 11.4 and 5.5 mm Hg more, respectively, than the control diet (P<0.001 for each); among the 326 subjects without hypertension, the corresponding reductions were 3.5 mm Hg (P<0.001) and 2.1 mm Hg (P=0.003). CONCLUSIONS: A diet rich in fruits, vegetables, and low-fat dairy foods and with reduced saturated and total fat can substantially lower blood pressure. This diet offers an additional nutritional approach to preventing and treating hypertension

Fostering support for non-democratic rule? Controlled political liberalization and popular support for non-democratic regimes

When the Cold War ended, many non-democratic regimes across the globe embarked on a course of controlled political liberalization, hoping to stabilize their autocratic rule by mitigating popular demands for democratization and increasing regime legitimacy. But does this strategy actually work? This article uses multi-level analyses to examine how the degree of political liberalization affects regime support in non-democratic political systems and to ascertain which mechanisms underlie this effect. Drawing on aggregate measures of political liberalization and comparative survey data from four regional survey projects and 31 non-democracies, the study's results indicate that the degree of liberalization has no decisively positive effect on regime support, suggesting controlled political liberalization might not be an effective legitimizing strategy after all.Nach Ende des Kalten Krieges haben viele nicht-demokratische Regime weltweit einen Kurs der begrenzten politischen Öffnung eingeschlagen, um öffentliche Forderungen nach Demokratisierung zu entschärfen und auf diese Weise die Legitimität ihrer autokratischen Herrschaft zu erhöhen. Doch ist diese Strategie tatsächlich effektiv? Der Beitrag verwendet Mehrebenenanalysen, um zu untersuchen wie der Grad an politischer Öffnung die Regimerunterstützung in nicht-demokratischen politischen Systemen beeinflusst. Auf Basis von Aggregatmaßen zur politischen Öffnung und Individualdaten aus vier regionalen Umfrageprojekten und 31 Autokratien kann kein klarer positiver Effekt des Grads der politischen Öffnung auf die Regimeunterstützung nachgewiesen werden, was eine begrenzte politische Öffnung als wenig effektive Legitimationsstrategie erscheinen lässt

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data