Richard Wright and Ralph Ellison: Master and protege

Negroes from Africa have been in America since 1620 when twenty Africans were sold to the white settlement of Jamestown, Virginia. Since that date, Negros have made a contribution to American history through their blood and sweat, their songs, and their cultural heritage. Yet, a peculiar institution of slavery arose on American soil, and black men and women were subjected to a subservient, second-class status

The Good Faith Requirement in Collective Bargaining

The Good Faith Requirement in Collective Bargainin

The development of food portion sizes suitable for 4–18‐year‐old children used in a theoretical meal plan meeting energy and nutrient requirements

Background: Healthy eating guidelines for school‐aged children are available but without advice on portion sizes. This is a concern because consuming large portions is associated with an increased risk of overweight/obesity. The present study aimed to calculate recommended portion sizes for school‐aged children based on weight for age and use them to develop a meal plan to meet nutritional needs within energy requirements. / Methods: Portion size data on foods consumed by school‐aged children (4–18 years) were extracted from two sources: (i) British National Diet and Nutrition Survey (1997) and (ii) Avon Longitudinal Study of Parents and Children (1997–2006). Foods were allocated to groups based on the UK Eatwell Guide and the US My Plate Model. Portion sizes were developed for a variety of foods. A meal plan that included portion size guidance and met healthy eating guidelines was developed based on the number of portions of each food group needed to meet dietary requirements. / Results: Portion sizes were developed for 131 foods that were commonly eaten by children in age groups 4–6, 7–10, 11–14 and 15–18 years. The meal plan met requirements for energy and nutrients as specified by UK dietary reference values, except for vitamin D for which there are few dietary sources. / Conclusions: Food portion sizes informed by usual intake in UK children can help inform dietary advice for a range of childhood settings and for parents. The meal plan included a wide variety of foods to encourage dietary diversity and meet energy and nutrient needs for school‐aged children

Healing After Simple Gingivectomy

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142136/1/jper0401.pd

Increasing and Detecting Memory Address Congruence

A static memory reference exhibits a unique property when its dynamic memory addresses are congruent with respect to some non-trivial modulus. Extraction of this congruence information at compile-time enables new classes of program optimization. In this paper, we present methods for forcing congruence among the dynamic addresses of a memory reference. We also introduce a compiler algorithm for detecting this property. Our transformations do not require interprocedural analysis and introduce almost no overhead. As a result, they can be incorporated into real compilation systems. On average, our transformations are able to achieve a five-fold increase in the number of congruent memory operations. We are then able to detect 95% of these references. This success is invaluable in providing performance gains in a variety of areas. When congruence information is incorporated into a vectorizing compiler, we can increase the performance of a G4 AltiVec processor up to a factor of two. Using the same methods, we are able to reduce energy consumption in a data cache by as much as 35%.Singapore-MIT Alliance (SMA

Foundation species identity and trophic complexity affect experimental seagrass communities

The abundance and species composition of marine foundation species is changing due to range expansion or contraction, with potentially important ecosystem-level consequences. In Chesapeake Bay, USA, warming is likely to favor the more heat and stress-tolerant Ruppia maritima (widgeongrass) over Zostera marina (eelgrass). Because of the key role of seagrasses in providing habitat and trophic support, it is important to determine whether the more stress-tolerant seagrass provides similar ecological functions to the species it may replace. We addressed how trophic control differs between communities associated with the 2 seagrass species in a mesocosm experiment. Grazing of epiphytic algae can benefit seagrasses over competing algae, and crustacean mesograzers are an important link for higher trophic levels. We manipulated seagrass density, species identity, and presence of grazers and predators, and examined the resulting communities of recruiting algae and invertebrates. Overall, predation was higher in Ruppia than in Zostera, although mesograzer species individually differed in their susceptibility to predation and response to seagrass species. The presence of grazers and predators had a greater overall effect on multivariate metrics of fouling community development than did seagrass species identity. Initial densities of seagrass and grazer species had interactive effects on some recruiting microalgae and tunicates. Differences in grazer composition and predation between seagrass species could have consequences for higher trophic levels that rely on fauna in seagrass beds. However, given the considerable effects of manipulated seagrass and mesograzer density on trophic interactions and the fouling community, it may be most important to consider the overall density and distribution of seagrass present, rather than seagrass species identity. Our results highlight the importance of testing redundancy in ecological functions among habitat-forming species

Subharmonics and Aperiodicity in Hysteresis Loops

We show that it is possible to have hysteretic behavior for magnets that does not form simple closed loops in steady state, but must cycle multiple times before returning to its initial state. We show this by studying the zero-temperature dynamics of the 3d Edwards Anderson spin glass. The specific multiple varies from system to system and is often quite large and increases with system size. The last result suggests that the magnetization could be aperiodic in the large system limit for some realizations of randomness. It should be possible to observe this phenomena in low-temperature experiments.Comment: 4 pages, 3 figure

Patterns and trends of topsoil carbon in the UK: complex interactions of land use change, climate and pollution

The UK Countryside Survey (CS) is a national long-term survey of soils and vegetation that spans three decades (1978–2007). Past studies using CS data have identified clear contrasting trends in topsoil organic carbon (tSOC) concentrations (0–15 cm) related to differences between habitat types. Here we firstly examine changes in tSOC resulting from land use change, and secondly construct mixed models to describe the impact of indirect drivers where land use has been constant. Where it occurs, land use change is a strong driver of SOC change, with largest changes in tSOC for transitions involving SOC-rich soils in upland and bog systems. Afforestation did not always increase tSOC, and the effect of transitions involving woodland was dependent on the other vegetation type. The overall national spatial pattern of tSOC concentration where land use has been constant is most strongly related to vegetation type and topsoil pH, with contributions from climate variables, deposition and geology. Comparisons of models for tSOC across time periods suggest that declining SO4 deposition has allowed recovery of topsoils from acidification, but that this has not resulted in the increased decomposition rates and loss of tSOC which might be expected. As a result, the relationship between pH and tSOC in UK topsoils has changed significantly between 1978 and 2007. The contributions of other indirect drivers in the models suggest negative relationships to seasonal temperature metrics and positive relationships to seasonal precipitation at the dry end of the scale. The results suggest that the CS approach of long-term collection of co-located vegetation and soil biophysical data provides essential tools both for identifying trends in tSOC at national and habitat levels, and for identifying areas of risk or areas with opportunities for managing topsoil SOC and vegetation change

Revisiting Garg's 2-Approximation Algorithm for the k-MST Problem in Graphs

This paper revisits the 2-approximation algorithm for $k$-MST presented by Garg in light of a recent paper of Paul et al.. In the $k$-MST problem, the goal is to return a tree spanning $k$ vertices of minimum total edge cost. Paul et al. extend Garg's primal-dual subroutine to improve the approximation ratios for the budgeted prize-collecting traveling salesman and minimum spanning tree problems. We follow their algorithm and analysis to provide a cleaner version of Garg's result. Additionally, we introduce the novel concept of a kernel which allows an easier visualization of the stages of the algorithm and a clearer understanding of the pruning phase. Other notable updates include presenting a linear programming formulation of the $k$-MST problem, including pseudocode, replacing the coloring scheme used by Garg with the simpler concept of neutral sets, and providing an explicit potential function.Comment: Proceedings of SIAM Symposium on Simplicity in Algorithms (SOSA) 202