Mechanical Properties Of Sediment Determine Burrowing Success And Influence Distribution Of Two Lugworm Species

We apply new perspectives on how organisms burrow by examining the association of in situ variation in sediment mechanical properties with burrowing ability and species distribution of two sympatric lugworms, Abarenicola pacifica and Abarenicola claparedi. We quantified the sediment\u27s resistance to penetration and its grain size distribution at sites inhabited by each species. Abarenicola pacifica individuals were found in significantly harder to penetrate, more heterogeneous sediments. We compared worm burrowing ability using reciprocal transplant experiments. Worms from firmer sediments, A. pacifica, were able to make successful steep burrows in sediments characteristic of either species. In contrast, A. claparedi individuals often failed to complete successful burrows in the firmer A. pacifica sediment. To examine how morphological differences could explain these patterns, we compared body wall musculature and measured how well individuals support their own bodies when draped over a cantilever. Lugworms from the firmer sediment had thicker body wall musculature and held their bodies more rigidly than did worms from softer sediments. Additionally, we observed subtle differences in the papillae on the proboscises\u27 surfaces, which could affect worm–sediment interactions, but we found no differences in the chaetae of the two species. Abarenicola claparedi produced more mucus, which could be important in shoring up burrow walls in their shifting, sandy habitat. This study presents the first example of using field-based experiments to determine how sediment mechanical properties and worm burrowing ability could act to determine organismal distribution. Our findings have broader ecological implications because of the role of lugworms as ecosystem engineers

Old and deer: A study of Neoarchean peridotites in Michigan’s Upper Peninsula

The Deer Lake Peridotite and the Presque Isle Periodotite are two ultramafic formations of Neoarchean age within the Ishpeming Greenstone Belt of Michigan’s Upper Peninsula, and are found only fifteen miles apart. The Deer Lake Peridotite was deformed in processes indicative of the broader, regional-scale tectonics of the region, but little study has been done on the mineralogy and extent and style of alteration. This research aims to better classify the mineralogy of the formation, with particular focus on textural variations observed in thin-section, as well as chemical analysis of samples taken from the formation. In addition, this research seeks to correlate the Deer Lake Peridotite’s history of alteration, which may have included alteration by Proterozoic events, with that of the Presque Isle Black Rocks, a formation which has had more extensive study done on its tectonic history and alteration. The comparison between alteration styles in the two formations will help draw conclusions about the tectonic history of Michigan’s Upper Peninsula

Exploring the school counselor\u27s role in response to intervention (rti) efforts for struggling readers in elementary grades

Student success is important for student learning, for parents, and for schools; however, in the last decade standardized test data has shed much light on the need for improved student performance across grade levels. Research findings identify that there are millions of struggling readers in US schools. Using assessment data, schools are implementing various types of intervention systems in an effort to meet all students\u27 needs. Response to Intervention (RtI) is a method of intervention that provides systematic assistance to students who have learning difficulties and need additional support beyond regular classroom instruction. Results showed that RtI related activities (i.e., academic, behavioral, social) encompassed the majority of the participating school counselors\u27 time and responsibilities. Additional results showed that because of the increased number of struggling learners in schools and the way schools view the school counselor\u27s responsibilities, a shift has occurred in their overall role. Participating counselors reported that they spend a fraction of their time in counseling and the majority of their time in managing cases; they deal with countless hours of paperwork and testing. Study results also raised questions about what RtI is, how the model is implemented in schools, and about a need to revisit the role of the school counselor within the RtI framework. Our students will benefit not only from quality instruction, assessment, support, and services, but they also need the valuable services of a school counselor. School counselors with the collaboration of teachers and parents provide the most beneficial way for student success

Macroscopic Model of a Cilium Appendage

The goal of this project is to develop a macroscopic model of the cilia appendage and a realistic testing environment for the model. The model should be created with materials that effectively replicate the material and mechanical properties of the appendage in the human body. Additionally, the testing environment should mimic the viscous fluid that surrounds cilia in the human body to allow for more accurate testing. The fluid’s flow should be parallel to the model and induce instability in the system. This instability should force the cilia model to oscillate like a flag in the wind. Upon completion of this project, our model should allow testers to gain a deeper understanding of cilia\u27s motion by observing and measuring these oscillations. Ideally, our model and testing environment will be transportable and easy to set up. This project is important because cilia malfunction can lead to many different diseases in the human body

Policy Disincentives to Home Sharing: A Focus on Income and Housing

James Weldon Johnson Professorship at New York University; The Eisner Foundation; Anonymous Donor

Three-dimensional architecture and biogenesis of membrane structures associated with hepatitis C virus replication

All positive strand RNA viruses are known to replicate their genomes in close association with intracellular membranes. In case of the hepatitis C virus (HCV), a member of the family Flaviviridae, infected cells contain accumulations of vesicles forming a membranous web (MW) that is thought to be the site of viral RNA replication. However, little is known about the biogenesis and three-dimensional structure of the MW. In this study we used a combination of immunofluorescence- and electron microscopy (EM)-based methods to analyze the membranous structures induced by HCV in infected cells. We found that the MW is derived primarily from the endoplasmic reticulum (ER) and contains markers of rough ER as well as markers of early and late endosomes, COP vesicles, mitochondria and lipid droplets (LDs). The main constituents of the MW are single and double membrane vesicles (DMVs). The latter predominate and the kinetic of their appearance correlates with kinetics of viral RNA replication. DMVs are induced primarily by NS5A whereas NS4B induces single membrane vesicles arguing that MW formation requires the concerted action of several HCV replicase proteins. Three-dimensional reconstructions identify DMVs as protrusions from the ER membrane into the cytosol, frequently connected to the ER membrane via a neck-like structure. In addition, late in infection multi-membrane vesicles become evident, presumably as a result of a stress-induced reaction. Thus, the morphology of the membranous rearrangements induced in HCV-infected cells resemble those of the unrelated picorna-, corona- and arteriviruses, but are clearly distinct from those of the closely related flaviviruses. These results reveal unexpected similarities between HCV and distantly related positive-strand RNA viruses presumably reflecting similarities in cellular pathways exploited by these viruses to establish their membranous replication factories

Unnatural selection of salmon life histories in a modified riverscape

Altered river flows and fragmented habitats often simplify riverine communities and favor non‐native fishes, but their influence on life‐history expression and survival is less clear. Here, we quantified the expression and ultimate success of diverse salmon emigration behaviors in an anthropogenically altered California river system. We analyzed two decades of Chinook salmon monitoring data to explore the influence of regulated flows on juvenile emigration phenology, abundance, and recruitment. We then followed seven cohorts into adulthood using otolith (ear stone) chemical archives to identify patterns in time‐ and size‐selective mortality along the migratory corridor. Suppressed winter flow cues were associated with delayed emigration timing, particularly in warm, dry years, which was also when selection against late migrants was the most extreme. Lower, less variable flows were also associated with reduced juvenile and adult production, highlighting the importance of streamflow for cohort success in these southernmost populations. While most juveniles emigrated from the natal stream as fry or smolts, the survivors were dominated by the rare few that left at intermediate sizes and times, coinciding with managed flows released before extreme summer temperatures. The consistent selection against early (small) and late (large) migrants counters prevailing ecological theory that predicts different traits to be favored under varying environmental conditions. Yet, even with this weakened portfolio, maintaining a broad distribution in migration traits still increased adult production and reduced variance. In years exhibiting large fry pulses, even marginal increases in their survival would have significantly boosted recruitment. However, management actions favoring any single phenotype could have negative evolutionary and demographic consequences, potentially reducing adaptability and population stability. To recover fish populations and support viable fisheries in a warming and increasingly unpredictable climate, coordinating flow and habitat management within and among watersheds will be critical to balance trait optimization versus diversification