Organism -sediment interactions: The role of seabed dynamics in structuring the mesohaline York River macrobenthic community

Estuaries are dynamic physical environments. The stability of the sediment-water interface is influenced by sources and rates of sediment delivery and physical reworking of sediments by currents, tides, waves and biology, but effects of disruption of this interface on benthic biology are poorly resolved. For this study, I investigated effects of prevalent gradients in seabed disturbance processes and associated seabed characteristics on estuarine benthic community structure and function in the mesohaline York River, a tributary of Chesapeake Bay, USA. I used a variety of approaches to characterize the seabed, including sediment grain size, sediment water content, maximum depth of 7Be, depth of the oxidized sediment layer, profiles of sediment Eh, physical structure of the sediment, sediment chlorophyll a, and sediment organic content. Differences in magnitude of deposition and subsequent reworking of sediments by physical processes were documented among the five benthic subenvironments sampled (south shoal, secondary channel, main channel flank, main channel, and north shoal). Temporal and spatial variations in spring recruitment were observed among subenvironments sampled weekly for recruits: the south shoal, secondary channel and main channel flank. Total recruitment was greatest in the main channel flank, which experienced the highest sediment deposition, and was limited in the secondary channel, which had the strongest tidal currents. The five benthic subenvironments sampled for patterns of community structure and estimates of secondary production were dominated by estuarine opportunist species. Total abundance was greatest in the north shoal, which experienced minimal deposition and physical reworking of sediment. Biomass and secondary production estimates were driven by presence of deep-dwelling bivalves, and were greatest in subenvironments that experienced deposition. These results suggest that variations in seabed characteristics across relatively small spatial scales can influence estuarine benthic community structure and function. Laboratory experiments were conducted to further elucidate the effect of sediment deposition on estuarine organism survival. Species representing both infaunal and epifaunal taxa ranged from highly susceptible to highly tolerant of burial by sediment. Survival was a function of organism motility, residence depth and perhaps physiological adaptations. Small, shallow-dwelling juveniles of some common estuarine species were highly tolerant of burial

In-plane magnetic reorientation in coupled ferro- and antiferromagnetic thin films

By studying coupled ferro- (FM) and antiferromagnetic (AFM) thin film systems, we obtain an in-plane magnetic reorientation as a function of temperature and FM film thickness. The interlayer exchange coupling causes a uniaxial anisotropy, which may compete with the intrinsic anisotropy of the FM film. Depending on the latter the total in-plane anisotropy of the FM film is either enhanced or reduced. Eventually a change of sign occurs, resulting in an in-plane magnetic reorientation between a collinear and an orthogonal magnetic arrangement of the two subsystems. A canted magnetic arrangement may occur, mediating between these two extremes. By measuring the anisotropy below and above the N\'eel temperature the interlayer exchange coupling can be determined. The calculations have been performed with a Heisenberg-like Hamiltonian by application of a two-spin mean-field theory.Comment: 4 pages, 4 figure

Requirements of an Integrated Formal Method for Intelligent Swarms

NASA is investigating new paradigms for future space exploration, heavily focused on the (still) emerging technologies of autonomous and autonomic systems [47, 48, 49]. Missions that rely on multiple, smaller, collaborating spacecraft, analogous to swarms in nature, are being investigated to supplement and complement traditional missions that rely on one large spacecraft [16]. The small spacecraft in such missions would each be able to operate on their own to accomplish a part of a mission, but would need to interact and exchange information with the other spacecraft to successfully execute the mission

Density data for Lake Ontario benthic invertebrate assemblages from 1964 to 2018

Benthic invertebrates are important trophic links in aquatic food webs and serve as useful bioindicators of environmental conditions because their responses integrate the effects of both water and sediment qualities. However, long-term data sets for benthic invertebrate assemblages across broad geographic areas are rare and, even if collected, historic data sets are often not readily accessible. This data set provides densities of benthic macroinvertebrates for all taxa collected during lake-wide surveys in Lake Ontario, a Laurentian Great Lake, from 1964 to 2018. This information resulted from surveys funded by the governments of the United States and Canada to investigate the status and changes of Lake Ontario benthic community. Of the 13 lake-wide benthic surveys conducted in Lake Ontario over the course of 54 yr, we were able to acquire taxonomic data to the species level for 11 of the surveys and data to the group level for the other two surveys. Density data are provided for taxa representing the Annelida, Arthropoda, Mollusca, Cnidaria, Nemertea, and Platyhelminthes phyla. Univariate and multivariate analyses revealed that the compositional structure of Lake Ontario invertebrate assemblages differed markedly by depth and were also significantly altered by the Dreissena spp. invasion in early 1990s. The introduction of invasive dreissenids has changed the community historically dominated by Diporeia, Oligochaeta, and Sphaeriidae, to a community dominated by quagga mussels and Oligochaeta. Considering the rarity of long-term benthic data of high taxonomic resolution in lake ecosystems, this data set could be useful to explore broader aspects of ecological theory, including effects of different environmental factors and invasive species on community organization, functional and phylogenetic diversity, and spatial scale of variation in community structure. The data set could also be useful for studies on individual species including abundance and distribution, species co-occurrence, and how the patterns of dominance and rarity change over space and time. Use of this data set for academic or educational purposes is encouraged as long as the data source is properly cited using the title of this Data Paper, the names of the authors, the year of publication, the journal name, and the article number

B Cells Regulate Neutrophilia during Mycobacterium tuberculosis Infection and BCG Vaccination by Modulating the Interleukin-17 Response

We have previously demonstrated that B cells can shape the immune response to Mycobacterium tuberculosis, including the level of neutrophil infiltration and granulomatous inflammation at the site of infection. The present study examined the mechanisms by which B cells regulate the host neutrophilic response upon exposure to mycobacteria and how neutrophilia may influence vaccine efficacy. To address these questions, a murine aerosol infection tuberculosis (TB) model and an intradermal (ID) ear BCG immunization mouse model, involving both the μMT strain and B cell-depleted C57BL/6 mice, were used. IL (interleukin)-17 neutralization and neutrophil depletion experiments using these systems provide evidence that B cells can regulate neutrophilia by modulating the IL-17 response during M. tuberculosis infection and BCG immunization. Exuberant neutrophilia at the site of immunization in B cell-deficient mice adversely affects dendritic cell (DC) migration to the draining lymph nodes and attenuates the development of the vaccine-induced Th1 response. The results suggest that B cells are required for the development of optimal protective anti-TB immunity upon BCG vaccination by regulating the IL-17/neutrophilic response. Administration of sera derived from M. tuberculosis-infected C57BL/6 wild-type mice reverses the lung neutrophilia phenotype in tuberculous μMT mice. Together, these observations provide insight into the mechanisms by which B cells and humoral immunity modulate vaccine-induced Th1 response and regulate neutrophila during M. tuberculosis infection and BCG immunization. © 2013 Kozakiewicz et al

Incidence and Risk Factors of Recurrence after Surgery for Pathology-proven Diverticular Disease

Contains fulltext : 69776.pdf (publisher's version ) (Closed access)BACKGROUND: Diverticular disease is a common problem in Western countries. Rationale for elective surgery is to prevent recurrent complicated diverticulitis and to reduce emergency procedures. Recurrent diverticulitis occurs in about 10% after resection. The pathogenesis for recurrence is not completely understood. We studied the incidence and risk factors for recurrence and the overall morbidity and mortality of surgical therapy for diverticular disease. METHODS: Medical records of 183 consecutive patients with pathology-proven diverticulitis were eligible for evaluation. Mean duration of follow-up was 7.2 years. Number of preoperative episodes, emergency or elective surgeries, type of operation, level of anastomosis, postoperative complications, persistent postoperative pain, complications associated with colostomy reversal, and recurrent diverticulitis were noted. The Kaplan-Meier method was used to calculate the cumulative probability of recurrence. Cox regression was used to identify possible risk factors for recurrence. RESULTS: The incidence of recurrence was 8.7%, with an estimated risk of recurrence over a 15-year period of 16%. Risk factors associated with recurrence were (younger) age (p < 0.02) and the persistence of postoperative pain (p < 0.005). Persistent abdominal pain after surgery was present in 22%. Eighty percent of patients who needed emergency surgery for acute diverticulitis had no manifestation of diverticular disease prior to surgery. In addition, recurrent diverticulitis was not associated with a higher percentage of emergency procedures. CONCLUSION: Estimated risk of recurrence is high and abdominal complaints after surgical therapy for diverticulitis are frequent. Younger age and persistence of postoperative symptoms predict recurrent diverticulitis after resection. The clinical implication of these findings needs further investigation. The results of this study support the careful selection of patients for surgery for diverticulitis

Analysis of Texas LoanSTAR Data

The analysis effort during the first year of the Texas LoanSTAR Monitoring and Analysis Program has emphasized selection and development of baseline analysis techniques to cover the range of buildings expected in the program. PRISM has been adopted as the baseline technique for buildings which are appropriate for treatment with one-, three- and five- parameter segmented linear, change-point models. In addition to PRISM, two- and four- parameter linear, segmented change-point models are expected to be suitable for at least preliminary analysis of monthly and daily data for all buildings in the program. Regression analysis with hourly scheduling profiles will be used for baseline analysis of hourly data. Substantial effort has been devoted to exploratory analysis intended to refine the analysis performed with the baseline techniques. Work to date has centered on investigation of Principal Component Analysis, an improved goodness-of-fit indicator for n-parameter change-point models, and calibrated simulation modeling. Data from five buildings is used to explain and illustrate the baseline analysis techniques and the exploratory work conducted

Acute epiglottitis as the initial presentation of pediatric Systemic Lupus Erythematosus

We report a case of a 5-year old girl, who initially presented with acute epiglottitis, sepsis and multi-organ failure. She was subsequently diagnosed as having Systemic Lupus Erythematosus. To the best of our knowledge, this article describes the first case of Haemophilus influenzae type f epiglottitis as the initial presentation of SLE in childhood

The Changing Face of Winter: Lessons and Questions From the Laurentian Great Lakes

Among its many impacts, climate warming is leading to increasing winter air temperatures, decreasing ice cover extent, and changing winter precipitation patterns over the Laurentian Great Lakes and their watershed. Understanding and predicting the consequences of these changes is impeded by a shortage of winter-period studies on most aspects of Great Lake limnology. In this review, we summarize what is known about the Great Lakes during their 3–6 months of winter and identify key open questions about the physics, chemistry, and biology of the Laurentian Great Lakes and other large, seasonally frozen lakes. Existing studies show that winter conditions have important effects on physical, biogeochemical, and biological processes, not only during winter but in subsequent seasons as well. Ice cover, the extent of which fluctuates dramatically among years and the five lakes, emerges as a key variable that controls many aspects of the functioning of the Great Lakes ecosystem. Studies on the properties and formation of Great Lakes ice, its effect on vertical and horizontal mixing, light conditions, and biota, along with winter measurements of fundamental state and rate parameters in the lakes and their watersheds are needed to close the winter knowledge gap. Overcoming the formidable logistical challenges of winter research on these large and dynamic ecosystems may require investment in new, specialized research infrastructure. Perhaps more importantly, it will demand broader recognition of the value of such work and collaboration between physicists, geochemists, and biologists working on the world\u27s seasonally freezing lakes and seas