Crystal Growth Furnace System Configuration and Planned Experiments on the Second United States Microgravity Laboratory Mission

The Crystal Growth Furnace (CGF) is currently undergoing modifications and refurbishment and is currently undergoing modifications and refurbishment and is manifested to refly on the Second United States Microgravity Laboratory (USML-2) mission scheduled for launch in September 1995. The CGF was developed for the National Aeronautics and Space Administration (NASA) under the Microgravity Science and Applications Division (MSAD) programs at NASA Headquarters. The refurbishment and reflight program is being managed by the Marshall Space Flight Center (MSFC) in Huntsville, Alabama. Funding and program support for the CGF project is provided to MSFC by the office of Life and Microgravity Sciences and Applications at NASA Headquarters. This paper presents an overview of the CGF system configuration for the USML-2 mission, and provides a brief description of the planned on-orbit experiment operation

A conceptual framework for invasion in microbial communities

There is a growing interest in controlling-promoting or avoiding-the invasion of microbial communities by new community members. Resource availability and community structure have been reported as determinants of invasion success. However, most invasion studies do not adhere to a coherent and consistent terminology nor always include rigorous interpretations of the processes behind invasion. Therefore, we suggest that a consistent set of definitions and a rigorous conceptual framework are needed. We define invasion in a microbial community as the establishment of an alien microbial type in a resident community and argue how simple criteria to define aliens, residents, and alien establishment can be applied for a wide variety of communities. In addition, we suggest an adoption of the community ecology framework advanced by Vellend (2010) to clarify potential determinants of invasion. This framework identifies four fundamental processes that control community dynamics: dispersal, selection, drift and diversification. While selection has received ample attention in microbial community invasion research, the three other processes are often overlooked. Here, we elaborate on the relevance of all four processes and conclude that invasion experiments should be designed to elucidate the role of dispersal, drift and diversification, in order to obtain a complete picture of invasion as a community process

Trait-based approaches to zooplankton communities

Zooplankton are major primary consumers and predators in most aquatic ecosystems. They exhibit tremendous diversity of traits, ecological strategies and, consequently, impacts on other trophic levels and the cycling of materials and energy. An adequate representation of this diversity in community and ecosystem models is necessary to generate realistic predictions on the functioning of aquatic ecosystems but remains extremely challenging. We propose that the use of trait-based approaches is a promising way to reduce complexity while retaining realism in developing novel descriptions of zooplankton in ecosystem models. Characterizing zooplankton traits and trade-offs will also be helpful in understanding the selection pressures and diversity patterns that emerge in different ecosystems along major environmental gradients. Zooplankton traits can be characterized according to their function and type. Some traits, such as body size and motility, transcend several functions and are major determinants of zooplankton ecological strategies. Future developments of trait-based approaches to zooplankton should assemble a comprehensive matrix of key traits for diverse groups and explore it for general patterns; develop novel predictive models that explicitly incorporate traits and associated trade-offs; and utilize these traits to explain and predict zooplankton community structure and dynamics under different environmental conditions, including global change scenarios. © 2013 The Author

Planktonic events may cause polymictic-dimictic regime shifts in temperate lakes

Water transparency affects the thermal structure of lakes, and within certain lake depth ranges, it can determine whether a lake mixes regularly (polymictic regime) or stratifies continuously (dimictic regime) from spring through summer. Phytoplankton biomass can influence transparency but the effect of its seasonal pattern on stratification is unknown. Therefore we analysed long term field data from two lakes of similar depth, transparency and climate but one polymictic and one dimictic, and simulated a conceptual lake with a hydrodynamic model. Transparency in the study lakes was typically low during spring and summer blooms and high in between during the clear water phase (CWP), caused when zooplankton graze the spring bloom. The effect of variability of transparency on thermal structure was stronger at intermediate transparency and stronger during a critical window in spring when the rate of lake warming is highest. Whereas the spring bloom strengthened stratification in spring, the CWP weakened it in summer. The presence or absence of the CWP influenced stratification duration and under some conditions determined the mixing regime. Therefore seasonal plankton dynamics, including biotic interactions that suppress the CWP, can influence lake temperatures, stratification duration, and potentially also the mixing regime

Take the Monkey and Run

The common marmoset (Callithrix jacchus) is a small, New World primate that is used extensively in biomedical and behavioral research. This short-lived primate, with its small body size, ease of handling, and docile temperament, has emerged as a valuable model for aging and neurodegenerative research. A growing body of research has indicated exercise, aerobic exercise especially, imparts beneficial effects to normal aging. Understanding the mechanisms underlying these positive effects of exercise, and the degree to which exercise has neurotherapeutic effects, is an important research focus. Thus, developing techniques to engage marmosets in aerobic exercise would have great advantages

The biogeography of abundant and rare bacterioplankton in the lakes and reservoirs of China.

Bacteria play key roles in the ecology of both aquatic and terrestrial ecosystems; however, little is known about their diversity and biogeography, especially in the rare microbial biosphere of inland freshwater ecosystems. Here we investigated aspects of the community ecology and geographical distribution of abundant and rare bacterioplankton using high-throughput sequencing and examined the relative influence of local environmental variables and regional (spatial) factors on their geographical distribution patterns in 42 lakes and reservoirs across China. Our results showed that the geographical patterns of abundant and rare bacterial subcommunities were generally similar, and both of them showed a significant distance-decay relationship. This suggests that the rare bacterial biosphere is not a random assembly, as some authors have assumed, and that its distribution is most likely subject to the same ecological processes that control abundant taxa. However, we identified some differences between the abundant and rare groups as both groups of bacteria showed a significant positive relationship between sites occupancy and abundance, but the abundant bacteria exhibited a weaker distance-decay relationship than the rare bacteria. Our results implied that rare subcommunities were mostly governed by local environmental variables, whereas the abundant subcommunities were mainly affected by regional factors. In addition, both local and regional variables that were significantly related to the spatial variation of abundant bacterial community composition were different to those of rare ones, suggesting that abundant and rare bacteria may have discrepant ecological niches and may play different roles in natural ecosystems

Can filter-feeding fishes improve water quality in lakes?

Summary 1. In this paper we examine the potential of a cichlid fish species (Sarotherodon galilaeus) to both maintain positive growth rates through filter-feeding on phytoplankton and improve water quality in Lake Kinneret through suppression of dinoflagellate (Peridinium gatunense) blooms. 2. Seasonal plankton consumption by S. galilaeus from Lake Kinneret was examined experimentally by monitoring changes in plankton assemblages during 24 h in 5-m 3 mesocosms containing varying densities of fish. Taxon-specific grazing rates ranged from 0 to 17 mg g fish day -1 , with mean total consumption of 1.6% fish body weight per day. During the spring bloom of P. gatunense, S. galilaeus consumed mostly (94%) netphytoplankton ( ‡20 lm). The remaining 6% consisted mostly of nanophytoplankton (<20 lm). During the summer and fall, net-and nanophytoplankton accounted for 54 and 42%, respectively, of the diet of S. galilaeus. Zooplankton and flagellated and ciliated protozoans made up the remaining 4%. 3. Simulations using a fish bioenergetics model indicated that consumption rates (C) were near maximum in spring (90% C max ), while consumption was reduced in summerfall (59% C max ). Sarotherodon galilaeus obtains sufficient energy through filter-feeding yearround, although most growth ( ‡60 %) occurs during the spring P. gatunense bloom. 4. Despite efficient feeding on P. gatunense and nanophytoplankton by S. galilaeus, estimates of instantaneous plankton mortality caused by ingestion were two orders of magnitude lower than maximum potential plankton growth rates. Thus the potential for the S. galilaeus population in Lake Kinneret to positively affect water quality through algal suppression is low

Exploitation and destabilization of a warm, freshwater ecosystem through engineered hydrological change

Exploitation of freshwater resources is having catastrophic effects on the ecological dynamics, stability, and quality of those water resources on a global scale, especially in arid and semiarid regions. Lake Kinneret, Israel (the Biblical Sea of Galilee), the only major natural freshwater lake in the Middle East, has been transformed functionally into a reservoir over the course of ∼70 years of hydrological alterations aimed mostly at producing electrical power and increasing domestic and agricultural water supply. Historical changes in lake chemistry and biology were reconstructed using analysis of sedimentary nutrient content, stable and radioisotope composition, biochemical and morphological fossils from algae, remains of aquatic invertebrates, and chemical indices of past light regimes. Together, these paleolimnological analyses of the lake's bottom sediments revealed that this transformation has been accompanied by acceleration in the rate of eutrophication, as indicated by increased accumulation rates of phosphorus, nitrogen, organic matter, phytoplankton and bacterial pigments, and remains of phytoplankton and zooplankton. Substantial increases in these indices of eutrophication coincide with periods of increased water‐level fluctuations and drainage of a major upstream wetland in the early to middle 20th century and suggest that management of the lake for increased water supply has degraded water quality to the point that ecosystem stability and sustainability are threatened. Such destabilization may be a model for eutrophication of freshwater lakes in other arid regions of the world in which management emphasizes water quantity over quality.Peer reviewedZoolog

Corrigendum to: The global Microcystis interactome

Corrigendum to "The global Microcystis interactome

Volume 01

Introduction from Dean Dr. Charles Ross Three Decades of Digging: Undergraduate Archeology at Longwood by Jessica Fields and Stephanie Neeley Interactions of Allelopathy and Heat Stress in Plants by Derek W. Hambright and Mary E. Lehman Inertial Electrostatic Confinement D-D Fusion Device: Construction and Simulation by Andrew R. Grzankowski Shackled Nim by Zachary Johnson Development of GC-MS and Chemometric Methods for the Analysis of Accelerants in Arson Cases by Boone M. Prentice A Comparison of Image Analysis Methods in cDNA Microarrays by Ashley M. Swandby Perceived Sexual Activity of Short and Long-Term Relationships by Victoria Morgan and Katie Williamson Elderly Male Communication by Kristine G. Bender Three Poems: “Adam and Eve and an Orange Tree”, “The Name of Everything Before Dying”, and “The ‘Poet Voice’” by Katelyn N. Romaine There\u27s Nothing Like Dancing, After All : Marriage and Gender in the Dance Scenes of Jane Austen\u27s Novels by D. Nicole Swann Two Poems: “Age Nine with Mother” and “The Apple That Crawls Away From the Tree” by Jessica Fox Untitled by Mike McAteer Room 9 by Alex Grabiec Two Photographs: “Gracie” and “Emily” by Laura Nodtvedt Bowling Lanes Night by Nick Costa Two Paintings: “Can and Kettle” and “Scarecrow” by Rachel Wolfe Exploring Henrik Ibsen\u27s “Perr Gynt” by Zack Dalton Creative Writing Scholarship at Longwood University Music Scholarship at Longwood – Senior Recital Arianne K. Burrus Longwood University Theater – Peer Gyn