The effects of inorganic nitrogen and phosphorus enrichment on herbaceous species growth of the Kimages Creek wetland (VA)

Dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) infiltrate waterways through fertilizer application, urban stormwater runoff, and sewer infrastructure leaks. As surrounding waterbodies experience increased DIN and DIP inputs, wetlands can experience corresponding nutrient enrichment. Vegetation uses DIN and DIP for structural growth, color, and seed production. Changes in DIN and DIP availability can influence species distribution due to differences in photosynthetic rates, root morphology and structure, and tissue type. DIP and DIN inputs are projected to increase 15-30% and 30-60% in the next fifty years¹. It is of interest to examine plant growth characteristics within this nutrient enrichment projection as well as nutrient enrichment from a potential 100-year projection to analyze future species composition responses within a freshwater tidal marsh

Connected to the Organization: A Survey of Communication Technologies in the Modern Organizational Landscape

In today’s organizations, traditional and cutting-edge technologies compete for increased usage. This exploratory project provides a snapshot of the communication technology (CT) landscape by examining the use of 25 different CTs and their relations to a variety of common demographic variables. Results suggest that, although newer CTs are in use today, more traditional and established CTs such as e-mail, Internet, telephones, and voicemail still dominate the landscape

Probing Gravity with Spacetime Sirens

A gravitational observatory such as LISA will detect coalescing pairs of massive black holes, accurately measure their luminosity distance and help identify a host galaxy or an electromagnetic counterpart. If dark energy is a manifestation of modified gravity on large scales, gravitational waves from cosmologically-distant spacetime sirens are direct probes of this new physics. For example, a gravitational Hubble diagram based on black hole pair luminosity distances and host galaxy redshifts could reveal a large distance extra-dimensional leakage of gravity. Various additional signatures may be expected in a gravitational signal propagated over cosmological scales.Comment: 11 pages, 1 figure, accepted for publication in ApJ Letter

Hospital and Physician Capacity Update

Offers an alternative view of healthcare costs by examining trends in hospital capacity and healthcare labor across regions. Outlines how effective management of healthcare capacity would enable affordable quality care that meets patient needs and wants

Merlin Phosphorylation by p21-activated Kinase 2 and Effects of Phosphorylation on Merlin Localization

The Nf2 tumor suppressor gene product merlin is related to the membrane-cytoskeleton linker proteins of the band 4.1 superfamily, including ezrin, radixin, and moesin (ERMs). Merlin is regulated by phosphorylation in a Rac/cdc42-dependent fashion. We report that the phosphorylation of merlin at serine 518 is induced by the p21-activated kinase PAK2. This is demonstrated by biochemical fractionation, use of active and dominant-negative mutants of PAK2, and immunodepletion. By using wild-type and mutated forms of merlin and phospho-directed antibodies, we show that phosphorylation of merlin at serine 518 leads to dramatic protein relocalization. Neurofibromatosis type 2 (NF2)1 is an inherited disorder characterized by the development of Schwann cell tumors of the eighth cranial nerve. Mutations and loss of heterozygosity of theNF2 gene have been detected in NF2 patients and in various sporadic tumors, including schwannomas, meningiomas, and ependymomas (1). In further support of a role for NF2 in tumor suppression, mice heterozygous for an Nf2 mutation are predisposed to a wide variety of tumors with high metastatic potential (2). In a separate model in which Nf2 is inactivated specifically in Schwann cells, mice develop schwannomas and Schwann cell hyperplasia (3). The longest and predominant splice form of the Nf2gene codes for a 595-amino acid protein highly similar to the band 4.1 family of proteins. It is most closely related to the ERM proteins,moesin, ezrin, and radixin. The ERM proteins are thought to function as cell membrane-cytoskeleton linkers and are localized to cortical actin structures near the plasma membrane such as microvilli, membrane ruffles, and lamellipodia (4, 5). Likewise, merlin is localized to cortical actin structures, in patterns that partially overlap with the ERMs (1). It has been proposed that intramolecular binding of the N-terminal and C-terminal domains conformationally regulates the ERM proteins by masking binding sites for interacting proteins. The ERMs can also form homodimers and heterodimers, among themselves and with merlin, adding an additional level of complexity to the regulation of these proteins (6). The recently solved crystal structure of the moesin N/C-terminal complex strengthens this model of conformational regulation (7). Given the sequence and, most likely, structural similarities of merlin to the ERM proteins, it is possible that merlin itself could be regulated in a similar fashion. Recent studies (8, 9) have implicated additional factors in the regulation of the ERMs, including phospholipids and phosphorylation. Previous work from our group and others (10, 11) has shown that merlin is differentially phosphorylated as well and that merlin protein levels are affected by growth conditions such as cell confluency, loss of adhesion, or serum deprivation. Merlin is found in an hypophosphorylated form when the combination of cellular and environmental conditions are growth-inhibitory (10). ERMs can be phosphorylated by Rho kinase, and this phosphorylation can affect intramolecular association and cellular localization. Phosphorylation and/or phospholipids may promote the transition of the proteins to an active form by “opening” intra- and intermolecular associations. These active monomers can then bind to other interacting proteins and the actin cytoskeleton and induce actin-rich membrane projections (5,8, 12, 13). The induction of merlin phosphorylation by activated alleles of the Rho family GTPases has also been examined. Interestingly, although activated Rho did not induce noticeable phosphorylation of merlin, activated forms of Rac and cdc42 did. The site of Rac-induced phosphorylation was determined to be a serine at position 518; mutation of serine 518 results in reduced basal phosphorylation and eliminated Rac-induced phosphorylation (11). Although Rac and cdc42 are implicated in the regulation of many pathways, they are most associated with regulation of cytoskeleton reorganization and gene expression (for recent reviews see Refs.14-16). In light of the data demonstrating that activated Rac/cdc42 leads to phosphorylation and possible inactivation of merlin, the elucidation of the responsible effector pathways and their effects on merlin function are of major importance. Understanding this regulation of merlin could lead to a more complete appreciation of the effects of merlin loss in tumors

Beyond Exploitation: Metadata Justice and Prison Labor

Large-scale digitization projects require enormous amounts of resources and labor, both of which are frequently in short supply in libraries and archives. How, then, has Oklahoma’s Yearbook Project been able to scan and process high school yearbooks at no cost for schools, libraries, museums, and historical societies? As a service of Oklahoma Correctional Industries, a state-level prison industry program, the Yearbook Project relied on the penal labor exemption of the Thirteenth Amendment which allows for involuntary servitude to occur behind prison bars. Although the Yearbook Project is currently on hiatus due to an ongoing investigation, metadata specialists, cataloguers, and the wider memory work community must still grapple with the legacy of this and other exploitative and unethical programs that have contributed to the resources and services we offer patrons. This presentation sheds light on the issue of exploitative prison labor on behalf of libraries and archives, and offers a solution grounded in metadata justice: labeling items, collections, and databases that benefit from exploitative labo

A Neural Circuit of Appetite Control in C. elegans

Feeding behavior and its associated neural circuitry is complex and intricate in mammalian systems, however, a simple model organism, such as C. elegans provides a more basic approach to understand factors and molecules involved. The fruit-dwelling nematode provides a unique set of resources; it only consists of 959 cells, 302 of which are neurons. In addition, each neuron’s connectivity and position within the worm is known and consistent between animals. Conservation of neurotransmitters and biochemical processes add to this impressive list. These resources provide an excellent background to address feeding behavior and the neural structures governing it. Feeding behavior in worms mimics feeding behavior in more complex organisms. They decide when to eat based on recent feeding behavior, current nutritional status, availability of food, and familiarity with the food available. Following starvation and refeeding worms enter a behavioral state similar to post-prandial sleep. The worms will stop eating and stop moving, in a state referred to as satiety quiescence. The ability to enter this state and maintain it is dependent on a pair of neurons in the head of C. elegans called ASI. Using calcium imaging and an automated satiety quiescence assay, our lab has found that this neuron pair is important for entering satiety quiescence and senses food. Feeding behavior, such as satiety quiescence, is regulated by numerous factors internal and external to the worm. Another pair of head neurons, ASH are capable of suppressing ASI’s activity in the presence of noxious stimuli and the presence of nutrients (potentially acting via ASI) can suppress ASH’s activation to noxious stimuli under starvation conditions. The interaction between these two neuron pairs can be regulated by other signals from the rest of the worm. We identified an opioid signal that can modulate the response of ASI to noxious stimulus signaling from ASH under starvation conditions. Other signals were identified to influence satiety behavior and this circuit including serotonin, octopamine, glutamate, and adenosine. In addition to these signals, a group of transcription factors were identified that may play a role in conveying the status of fat storage within the worm to its nervous system. Nuclear hormone receptors were found to increase their expression during starvation then decrease their expression upon refeeding. Upon completion of this work, we have a reached a greater understanding of the internal and external conditions governing feeding and avoidance behaviors

Performing Critical Pedagogy Through Fireside Chats

In this essay, I introduce fireside chats as a critical pedagogical practice, which can strengthen students' compassion and contemplation by enhancing communication practices and opening discussion about students' learning ideas, dreams, reflections, questions, and fears, while changing hierarchical communication patterns between teachers and students.