Interview with Scott and Carrie Logan by Mike Hastings

Biographical NoteScott Logan was born on February 17, 1977, in Exeter, New Hampshire. His father, Terence Logan, held a Ph.D. from Harvard University and taught English at the University of New Hampshire. Scott’s mother was from rural southern Maryland, and they met at Newton College of the Sacred Heart, in Newton, Massachusetts, where Terence was a professor and Scott’s mother was a student. Scott grew up in Kennebunk, Maine, and was interested in collecting and selling antiques, and in local history. For this business, he received a scholarship from the National Association of the Self-Employed. He was also one of the first Mitchell Scholars, in 1995, attending Bowdoin College and graduating in 1999. He first met his future wife, Carrie, at Bowdoin through their mutual membership in Alpha Delta Phi fraternity. He worked at Christie’s Auction Company and then the auctioneering firm Skinner, Inc. He then attended law school at Boston College, and at the time of this interview, he was an attorney specializing in consumer bankruptcy. Carrie Logan was born on December 24, 1977, in Portland, Maine, to Donald McGilvery and Cheryl Poulin McGilvery. Her parents, both from Maine, met at Cony High School, and both were graduated from the University of Maine, Orono. Her father worked in architecture and construction management for the Maine State Housing Authority, and her mother worked in education and at the time of this interview was the secretary at William H. Rowe School in Yarmouth. Carrie grew up in Yarmouth, Maine, attended Yarmouth public schools, and was selected as a Mitchell Scholar. She attended Bowdoin College, where she met Scott, and was graduated with the class of 2000. Through the Teach For America program, she taught in Opelousas, Louisiana, for two years and then became an English-as-a-Second-Language teacher in Houston, Texas, before returning to Maine to study at the University of Maine School of Law. She took her law degree in 2007 and was practicing business and real estate law at Preti Flaherty in Portland, Maine, at the time of this interview. SummaryInterview includes discussion of: Scott’s family and educational background in Kennebunk; Scott’s antique bottle interest; Scott’s education; Carrie’s family and educational background in Yarmouth; the decision to go to Bowdoin College; paying for college; the Mitchell Institute and Mitchell Scholarship; life at Bowdoin and Alpha Delta Phi; Carrie’s work teaching in the South with Teach for America; coming back to Maine; Scott dealing antiques; and more recent involvement with the Mitchell Institute

Effects of siRNA-mediated knockdown of GSK3β on retinal ganglion cell survival and neurite/axon growth

There are contradictory reports on the role of the serine/threonine kinase isoform glycogen synthase kinase-3β (GSK3β) after injury to the central nervous system (CNS). Some report that GSK3 activity promotes axonal growth or myelin disinhibition, whilst others report that GSK3 activity prevents axon regeneration. In this study, we sought to clarify if suppression of GSK3β alone and in combination with the cellular-stress-induced factor RTP801 (also known as REDD1: regulated in development and DNA damage response protein), using translationally relevant siRNAs, promotes retinal ganglion cell (RGC) survival and neurite outgrowth/axon regeneration. Adult mixed retinal cell cultures, prepared from rats at five days after optic nerve crush (ONC) to activate retinal glia, were treated with siRNA to GSK3β (siGSK3β) alone or in combination with siRTP801 and RGC survival and neurite outgrowth were quantified in the presence and absence of Rapamycin or inhibitory Nogo-A peptides. In in vivo experiments, either siGSK3β alone or in combination with siRTP801 were intravitreally injected every eight days after ONC and RGC survival and axon regeneration was assessed at 24 days. Optimal doses of siGSK3β alone promoted significant RGC survival, increasing the number of RGC with neurites without affecting neurite length, an effect that was sensitive to Rapamycin. In addition, knockdown of GSK3β overcame Nogo-A-mediated neurite growth inhibition. Knockdown of GSK3β after ONC in vivo enhanced RGC survival but not axon number or length, without potentiating glial activation. Knockdown of RTP801 increased both RGC survival and axon regeneration, whilst the combined knockdown of GSK3β and RTP801 significantly increased RGC survival, neurite outgrowth, and axon regeneration over and above that observed for siGSK3β or siRTP801 alone. These results suggest that GSK3β suppression promotes RGC survival and axon initiation whilst, when in combination with RTP801, it also enhanced disinhibited axon elongation

High-Latitude Tree Growth and Satellite Vegetation Indices: Correlations and Trends in Russia and Canada (1982-2008)

Vegetation in northern high latitudes affects regional and global climate through energy partitioning and carbon storage. Spaceborne observations of vegetation, largely based on the normalized difference vegetation index (NDVI), suggest decreased productivity during recent decades in many regions of the Eurasian and North American boreal forests. To improve interpretation of NDVI trends over forest regions, we examined the relationship between NDVI from the advanced very high resolution radiometers and tree ring width measurements, a proxy of tree productivity. We collected tree core samples from spruce, pine, and larch at 22 sites in northeast Russia and northwest Canada. Annual growth rings were measured and used to generate site-level ring width index (RWI) chronologies. Correlation analysis was used to assess the association between RWI and summer NDVI from 1982 to 2008, while linear regression was used to examine trends in both measurements. The correlation between NDVI and RWI was highly variable across sites, though consistently positive (r = 0.43, SD = 0.19, n = 27). We observed significant temporal autocorrelation in both NDVI and RWI measurements at sites with evergreen conifers (spruce and pine), though weak autocorrelation at sites with deciduous conifers (larch). No sites exhibited a positive trend in both NDVI and RWI, although five sites showed negative trends in both measurements. While there are technological and physiological limitations to this approach, these findings demonstrate a positive association between NDVI and tree ring measurements, as well as the importance of considering lagged effects when modeling vegetation productivity using satellite data

Trans World Radio - Culvert Design

Trans World Radio (TWR) is a mission organization focused on broadcasting the Gospel around the world. TWR now serves 190 countries by transmitting in 275 languages, using radio to deliver the message to as many people as possible. The organization’s West Africa Transmitter Site in Benin currently has accessibility problems due to high streamflows and saturated ground conditions during the rainy season. The site also needs a secure perimeter to reduce trespassing and theft. To address these issues, our client, Garth Kennedy, Director of the West Africa Transmitter Station, has asked the team to design two culverts, one at the upstream property boundary and one at the downstream boundary. Culverts are advantageous for this scenario because they can act as a bridge, while the pipe size can be restricted to inhibit trespassing. Once the culverts are built, the fence and perimeter road can be extended over them. For both sides of the property, the team has designed a series of U-shaped, pre-cast concrete box culverts. The team calculated the design flows based on rainfall data and the topography of the site to determine the size and number of box sections. The team has also designed the culverts and the supporting concrete structures to bear the load of vehicles and the machinery on site. TWR plans to construct the pre-cast culverts on-site, and then build the supporting structures and install the culverts during their dry season.https://mosaic.messiah.edu/engr2021/1017/thumbnail.jp

Forest Composition Change and Biophysical Climate Feedbacks Across Boreal North America

Deciduous tree cover is expected to increase in North American boreal forests with climate warming and wildfire. This shift in composition has the potential to generate biophysical cooling via increased land surface albedo. Here we use Landsat-derived maps of continuous tree canopy cover and deciduous fractional composition to assess albedo change over recent decades. We find, on average, a small net decrease in deciduous fraction from 2000 to 2015 across boreal North America and from 1992 to 2015 across Canada, despite extensive fire disturbance that locally increased deciduous vegetation. We further find near-neutral net biophysical change in radiative forcing associated with albedo when aggregated across the domain. Thus, while there have been widespread changes in forest composition over the past several decades, the net changes in composition and associated post-fire radiative forcing have not induced systematic negative feedbacks to climate warming over the spatial and temporal scope of our study

The Prrx1eGFP Mouse Labels the Periosteum During Development and a Subpopulation of Osteogenic Periosteal Cells in the Adult

The identity of the cells that form the periosteum during development is controversial with current dogma suggesting these are derived from a Sox9-positive progenitor. Herein, we characterize a newly created Prrx1eGFP reporter transgenic mouse line during limb formation and postnatally. Interestingly, in the embryo Prrx1eGFP-labeled cells become restricted around the Sox9-positive cartilage anlage without themselves becoming Sox9-positive. In the adult, the Prrx1eGFP transgene live labels a subpopulation of cells within the periosteum that are enriched at specific sites, and this population is diminished in aged mice. The green fluorescent protein (GFP)-labeled subpopulation can be isolated using fluorescence-activated cell sorting (FACS) and represents approximately 8% of all isolated periosteal cells. The GFP-labeled subpopulation is significantly more osteogenic than unlabeled, GFP-negative periosteal cells. In addition, the osteogenic and chondrogenic capacity of periosteal cells in vitro can be extended with the addition of fibroblast growth factor (FGF) to the expansion media. We provide evidence to suggest that osteoblasts contributing to cortical bone formation in the embryo originate from Prrx1eGFP-positive cells within the perichondrium, which possibly piggyback on invading vascular cells and secrete new bone matrix. In summary, the Prrx1eGFP mouse is a powerful tool to visualize and isolate periosteal cells and to quantify their properties in the embryo and adult. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research

Impacts of Climate and Insect Herbivory on Productivity and Physiology of Trembling Aspen (Populus tremuloides) in Alaskan Boreal Forests

Climate change is impacting forested ecosystems worldwide, particularly in the Northern Hemisphere where warming has increased at a faster rate than the rest of the globe. As climate warms, trembling aspen (Populus tremuloides) is expected to become more successful in northern boreal forests because of its current presence in drier areas of North America. However, large-scale productivity decline of aspen has recently been documented throughout the United States and Canada as a result of drought and insect outbreaks. We used tree ring measurements (basal area increment (BAI) and stable carbon isotopes (δ 13C)) and remote sensing indices of vegetation productivity (NDVI) to study the impact of climate and damage by the aspen epidermal leaf miner (Phyllocnistis populiella) on aspen productivity and physiology in interior Alaska. We found that productivity decreased with greater leaf mining and was not sensitive to growing season (GS) moisture availability. Although productivity decreased during high leaf mining years, it recovered to pre-outbreak levels during years of low insect damage, suggesting a degree of resilience to P. populiella mining. Climate and leaf mining interacted to influence tree ring δ 13C, with greater leaf mining resulting in decreased δ 13C when GS moisture availability was low. We also found that NDVI was negatively associated with leaf mining, and positively correlated with BAI and the δ 13C decrease corresponding to mining. This suggests that NDVI is capturing not only variations in productivity, but also changes in physiology associated with P. populiella. Overall, these findings indicate that the indirect effects of P. populiella mining have a larger impact on aspen productivity and physiology than climate under current conditions, and is essential to consider when assessing growth, physiology and NDVI trends in interior Alaska