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The melanocortin system is a key regulator of appetite and food intake in vertebrates. This system includes the neuropeptides neuropeptide y (NPY), agouti-related peptide (AGRP), cocaine- and amphetamine-regulated transcript (CART), and pro-opiomelanocortin (POMC). An important center for appetite control in mammals is the hypothalamic arcuate nucleus, with neurons that coexpress either the orexigenic NPY/AGRP or the anorexigenic CART/POMC neuropeptides. In ray-finned fishes, such a center is less characterized. The Atlantic salmon (Salmo salar) has multiple genes of these neuropeptides due to whole-genome duplication events. To better understand the potential involvement of the melanocortin system in appetite and food intake control, we have mapped the mRNA expression of npy, agrp, cart, and pomc in the brain of Atlantic salmon parr using in situ hybridization. After identifying hypothalamic mRNA expression, we investigated the possible intracellular coexpression of npy/agrp and cart/pomc in the tuberal hypothalamus by fluorescent in situ hybridization. The results showed that the neuropeptides were widely distributed, especially in sensory and neuroendocrine brain regions. In the hypothalamic lateral tuberal nucleus, the putative homolog to the mammalian arcuate nucleus, npya, agrp1, cart2b, and pomca were predominantly localized in distinct neurons; however, some neurons coexpressed cart2b/pomca. This is the first demonstration of coexpression of cart2b/pomca in the tuberal hypothalamus of a teleost. Collectively, our data suggest that the lateral tuberal nucleus is the center for appetite control in salmon, similar to that of mammals. Extrahypothalamic brain regions might also be involved in regulating food intake, including the olfactory bulb, telencephalon, midbrain, and hindbrain.

The purpose of this research was to understand how students in different demographics in the state of Minnesota understand and perceive concepts relating to food systems. Schools within the demographic categories of large metropolitan/inner city, urban cluster, and rural areas were chosen to determine if perceptions and knowledge of students were dependent on the demographic in which they lived. A total of 204 students were surveyed using a variety of types of questions to address research objectives. Results indicate that students have a general understanding of food production and where their food comes from, but as food sources become more complex or items are less common, students become confused. Food access did vary, where rural students used gas stations more than their urban counterparts. Large metropolitan/inner city adolescents had higher occasional use of farmer’s market/food stands which can be used as a way to start educational understanding about local foods. Students have a strong willingness to learn more about food systems and other environmental topics in school, but agree that they are not often receiving this interaction in the classroom. All demographics had low interest in local food and gardening, but rural students did have more access to these foods. Implications from this study can help researchers and educators understand students’ knowledge and perceptions about the food system, how they influence it, and how this changes across demographics.

Restoring forb richness to the northern tallgrass prairie (U.S.A.) is often problematic. A potential solution is the establishment of native forb-seeded patches that can serve as colonization sites. This study was designed to determine the following: (1) the success at which native forbs sown in small patches can colonize the surrounding vegetation matrix and (2) whether soil amendments (C additions, P fertilization, and seed bank reduction) applied to the seeded sites can facilitate such colonization (patch quality). Colonization was investigated at (1) the immediate surrounding (1 m belt transect, BT) of the seeded sites and (2) in disturbed but not seeded patches located 3 m from the seeded site (out-plots). Soil amendments did not affect colonization, but native forb density in the BT and out-plots was correlated to the density of forbs in the seeded sites (r2 = 0.3, p < 0.01). Seeded native forb density in the out-plots was higher than in the adjacent BT (19 vs. 5 plants/m2), suggesting that competition from the matrix vegetation may be more important in forb colonization than distance from the source. Taller forbs with larger seeds showed advantages in colonization success. This study showed that the colonization of matrix vegetation with native forbs from seeded patches is a viable method for prairie reconstruction but requires the availability of disturbed sites. In most prairies, animal-generated soil disturbances are common. In their absence, disturbances of the vegetation matrix will need to be added to the management plan.

Questions How are plant species richness and diversity related to spatial autocorrelation under grazed and ungrazed conditions in grassland communities? Is spatial autocorrelation dissimilar within different plant communities? Location The grasslands of southeast North Dakota, USA. Methods The study was conducted during the summer of 2009 in six grasslands under different management (grazed vs ungrazed with fire) along a moisture gradient. Spatial autocorrelation at each site was measured along 50-m transects among three different landscape positions representing different moisture levels. Dissimogram multivariate analysis was used to measure the nugget, dissimilarity and patch diameter. Additionally, richness and Shannon diversity indices and nonmetric multidimensional scaling analysis were compared to the dissimogram results. Results Mean patch diameter was significantly higher in grazed mid-slope sites than in ungrazed sites. Spatial autocorrelation was not different between the landscape positions (higher, dry areas were not different from lower, mesic areas). However, plant species richness, diversity and community composition were found to be different between landscape positions and management, with key differences in the presence of certain invasive species. Conclusions Disturbance and moisture level were reflected differently in the spatial autocorrelation analysis compared to the richness, diversity and ordination analyses. This indicates that disturbance and management impacted spatial autocorrelation separate from plant community composition and species diversity. This also highlights changes in the plant community caused by different management actions and the spread of invasive species.

Understanding the knowledge and perceptions of adolescents is an integral part of creating better curriculum and education materials in the natural sciences. This study explores the challenges of working with a protected population in a public school setting in terms of Institutional Review Board standards, the complex process of a researcher gaining access to the public schools, and the difficulty in attaining both parental and youth consent. In total 39 school districts throughout the state of Minnesota, USA, were invited to participate in the study; school districts were contacted from three demographics including (1) large metropolitan/inner city, (2) urban cluster, and (3) rural. Overall, securing participation among all demographics was challenging, though rural populations were the easiest when compared with the other demographics. Differences between groups were related to how gatekeepers granted approval. More gatekeepers exist in larger school districts and areas with greater populations. The ongoing complexities of gaining access to adolescents in public school settings may cause problems in determining what students actually know about the natural sciences and could hinder creation of appropriate education materials based on this information. The information in this study can be used by researchers, extension professionals, and educators to better understand how to navigate the current challenges that exist when researching a protected population in public schools.

In the northern Great Plains (United States), sites with less than 20% of native species are difficult to restore. We have experimented with a restoration method that shows some promise. It consists of systematically installing simulated small-scale patches (8.0 m2 in size) over 25% of an old field and then seeding these patches with native species. The working hypothesis is that these patches will generate a constant source of propagules which in time will lead to increases in native species diversity within the surrounding grass matrix. The objective of this paper was to determine whether soil amendments should be used to facilitate the establishment and persistence of native species (primarily forbs) within these patches. We seeded the patches with a mixture of native grass and forb species and applied four soil treatments: P fertilization, C additions, C + P, and a control (no amendments). Results for the first 5 years were as follows: (1) seeded forb richness was mostly unaffected by soil amendments; (2) seeded and nonseeded forb biomass and density were substantially reduced by C additions, whereas they were unaffected or increased under P additions; (3) both seeded and non-native grass biomass substantially increased with C additions; and (4) there was an inverse relationship between native seeded forbs and non-native grass biomass. Our conclusions are that: (1) P amendments are a potential tool for enhancing native seeded forb biomass in simulated small-scale disturbance patches; and (2) C additions, although enhancing seeded grass biomass do not reduce the biomass of non-native grasses.

Evaluation in nonformal education programs and settings must be framed within its special context—one that demands elasticity, transformation, and collaboration on the part of evaluators.

Accurate assessments of the true elemental cellular content of carbon (C), nitrogen (N), and phosphorus (P) in bacteria have been a major difficulty in microbial research for some time. This study is the first to present single-cell elemental C, N, and P measurements on natural populations of bacteria from the Sargasso Sea using a transmission electron microscope (TEM) equipped with an X-ray detector unit. Elemental cell content showed a best fit as a power function of the cell size, and smaller bacteria had significantly more elemental C, N, and P per cell volume than the larger ones (scaling factor a < I ), contrary to coastal, brackish, and freshwater systems, the bacteria collected in this study appeared to have a molar elemental P:N close to the Redfield ratio of 0.063 (N: P = 16). The geometric mean of C per cell volume analyzed in this study (148 fg C μm -3 ) was higher than any other estimates reported from coastal and brackish water systems. Total amount of bacterial C calculated from abundance estimates requires an average conversion factor, and the choice of a representative bacterial cell volume is therefore critical. We were able to demonstrate that the outcome of biomass assessments is highly dependant on the choice of cell-specific conversion factors. By applying cell volumes previously reported from the BATS site, the average 0-250 m depth integration of bacterial C between 1991 and 1996 ranged between 1.7 and 2.5 times less than other recent biomass estimates for these waters.

In order to meet their financial goals, investors, whether institutions or individuals, must make asset allocation decisions by balancing their return targets with their tolerance for volatility, their liquidity requirements, and time horizons. Yet even optimal mixes of investments with regard to time horizon, liquidity, and volatility levels are sometimes not adequate to achieve the return objectives of a firm or an individual. Using leverage scales up both returns and risks, introducing the potential for default. When using leverage, either as a fund manager or as an investor into a fund, fully understanding the potential for default is absolutely necessary. Using standard measures of risk and return can be very misleading. Sharpe ratios and information ratios can lead the investor into a state of unwarranted comfort with respect to the probability of losing more than is acceptable. Many traditional measures of risk do not deal with this problem correctly. This paper takes a barrier option theoretic approach to analyzing the potential for losses and the potential for the leveraged investor to be knocked-out of his position even under circumstances of perfect knowledge of the end return. Thus, it demonstrates the necessity of a more rigorous approach to understanding the risk of any particular style of investment, particularly when dealing with hedge funds.

Heimlich and Norland suggest a process as a means for teachers to examine their beliefs and values about teaching, gain a better understanding of who they are as teachers, and develop a personal teaching style.

When constructing portfolios, practitioners must take opportunity cost into account and view returns as excess, not total returns. Using total returns in a means–variance optimization—a remarkably common error—introduces a bias that will cause “optimal” portfolios to overweight domestic cash securities at the expense of higher-risk instruments and instruments invested abroad. The original work on modern portfolio theory made little mention of excess versus total returns in optimization in part because the theory assumed one was only choosing between risky assets and that all of the assets were denominated in the same currency. Thus, those who refer to the original version of the theory could easily misapply it when considering assets in different currency zones. This paper seeks to demonstrate the problems and biases inherent in using total returns versus excess returns in means–variance optimization.

Aboveground production and shoot and root litter decomposition rates were measured in amended coarse taconite tailing plots over the second and third growing seasons of a 3-yr study. Plots were seeded with a mixture of native prairie species that included Andropogon gerardii Vitm., Schizachyrium scoparium (Michx.) Nash, Elymus canadensis L., Bromus kalmii Gray, and Lespedeza capitata Michx. Reclamation treatments included inoculation with indigenous mycorrhizal fungi, three rates of fertilizer, and three rates of composted yard waste. Aboveground plant biomass in plots amended with 44.8 Mg ha -1 compost increased from 150 g m -2 in the second season to 330 g m -2 in the third season. The litterbag technique was used to assess the influence of reclamation treatments on the decomposition of plant litter. Shoot litter placed on the surface lost 60 to 70% of its original mass after 15 mo and was unaffected by treatment during the first season but was slower in plots amended with 44.8 Mg ha -1 composted yard waste in the second season. Buried root tissue lost 40% of its original mass after 15 mo and was unaffected by treatment. By significantly increasing plant biomass and reducing litter decomposition rate in tailing, additions of 44.8 Mg ha -1 compost should result in the continued accrual of soil organic matter and begin to meet reclamation goals to establish self-sustaining native plant communities on tailing deposits.

Intracellular carbon (C), nitrogen (N) and phosphorus (P) content of marine phytoplankton and bacterioplankton can vary according to cell requirements or physiological acclimation to growth under nutrient limited conditions. Although such variation in macronutrient content is well known for cultured organisms, there is a dearth of data from natural populations that reside under a range of environmental conditions. Here, we compare C, N and P content of Synechococcus, Prochlorococcus, low nucleic acid (LNA) content bacterioplankton and small plastidic protists inhabiting surface waters of the North and South subtropical gyres and the Equatorial Region of the Atlantic Ocean. While intracellular C:N ratios ranged between 3.5 and 6, i.e. below the Redfield ratio of 6.6, all the C:P and N:P ratios were up to 10 times higher than the corresponding Redfield ratio of 106 and 16, respectively, reaching and in some cases exceeding maximum values reported in the literature. Similar C:P or N:P ratios in areas with different concentrations of inorganic phosphorus suggests that this is not just a response to the prevailing environmental conditions but an indication of the extremely low P content of these oceanic microbes.

Older workers re-entering the workforce and those changing jobs are coming to play an increasingly important role in the labor force, especially as part-time workers. Yet the work orientation and job satisfaction of these workers has not been studied. Do ‘situational’ factors such as skill and pay matter for this subgroup of workers, and if so, which ones? If significant factors exist, can their effect be explained by the mediating influence of ‘dispositional’ factors like work values? This paper explores these questions in a study of 198 older workers who had begun new, mostly part-time jobs. Regression analysis shows that the intrinsic indicators for skill and autonomy have a positive effect on job satisfaction. No extrinsic factor was significantly related to satisfaction, indicating that these workers are more than ‘instrumentally’ oriented. This support for a ‘situational’ interpretation of the impact of work, especially intrinsic features, was sustained in analyses which incorporated work values. To the extent that the growing number of part-time jobs are relatively low-skilled, and to the extent that older workers in new jobs are influenced most by intrinsically rewarding work, there appears to be a growing mismatch between an occupational niche and those who are being sought to fill it.