Petrocan

Poetry by Madelaine Longma

Suitability of leguminous cover crop pollens as food source for the green lacewing Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae).

Diversification of crops with species that provide suitable pollen for predators may reduce pest population on crops by enhancing predator effectiveness. In this paper we evaluated the suitability of leguminous cover crop pollens to the predatory green lacewing Chrysoperla externa (Hagen). The predator is commonly found in coffee agroecosystems and the plant species tested were pigeon pea and sunn hemp, which are used in organic coffee systems. Newly emerged females and males of C. externa were reared on diets containing pollen of pigeon pea, sunn hemp, or castor bean, used as a control. The reproductive success of C. externa was evaluated when females fed the pollen species and when honey was added to the diets, to verify the predator need for an extra carbohydrate source. Similar intrinsic growth rates were found for females fed on pigeon pea pollen and on sunn hemp pollen but these rates increased significantly when honey was added to the diets. Females fed with pigeon pea pollen plus honey and with sunn hemp pollen plus honey had higher intrinsic growth rates than those fed with castor bean pollen plus honey. Females fed on castor bean pollen only or on honey only, did not oviposit. Leguminous pollen species were equally suitable for C. externa especially when they were complemented with honey. The results suggest that to successfully enhance predator effectiveness, organic coffee plantation should be diversified with plant providing pollen in combination with plant providing nectar

MAKING HEADS OR TAILS: AN ICONOGRAPHIC ANALYSIS OF LATE MISSISSIPPIAN RIM-EFFIGY BOWLS IN THE CENTRAL MISSISSIPPI RIVER VALLEY

Symbolically charged ceramic rim-effigy bowls, characterized by figural head and tail adornments, are hallmarks of the Late Mississippian period in the central Mississippi River valley (CMV). Hundreds of whole rim-effigy bowls, most often depicting serpents, birds, or humans, have been collected at sites from southeastern Missouri to northwestern Mississippi. However, a comprehensive iconographic analysis of the CMV rim-effigy bowl corpus – specifically focused on visual style and theme – has never been conducted. A systematic review of the corpus’s imagery suggests that CMV rim-effigy bowls acted as materializations of the Mississippian cosmos, reinforcing the principle of cosmic balance. Further, given discrete concentrations of bowl styles and themes across the region, localized religious collectives – perhaps sodalities – may have produced their own rim-effigy bowls for use during charter rites or ceremonies. More broadly, by reviewing an understudied ceramic corpus, this study furthers understandings of Mississippian art and iconography in the CMV and beyond.Master of Art

Seasonality, phytoplankton succession and the biogeochemical impacts of an autumn storm in the northeast Atlantic Ocean

Phytoplankton chemotaxonomic distributions are examined in conjunction with taxon specific particulate biomass concentrations and phytoplankton abundances to investigate the biogeochemical consequences of the passage of an autumn storm in the northeast Atlantic Ocean. Chemotaxonomy indicated that the phytoplankton community was dominated by nanoplankton (2-20 μ), which on average represented 75±8% of the community. Microplankton (20-200 μ) and picoplankton (<2 μ) represented 21±7% and 4±3% respectively with the microplankton group composed of almost equal proportions of diatoms (53±17%) and dinoflagellates (47±17%). Total chlorophyll-a (TCHLa = CHLa + Divinyl CHLa) concentrations ranged from 22 to 677 ng L-1, with DvCHLa making minor contributions of between <1% and 13% to TCHLa. Higher DvCHLa contributions were seen during the storm, which deepened the surface mixed layer, increased mixed layer nutrient concentrations and vertically mixed the phytoplankton community leading to a post-storm increase in surface chlorophyll concentrations. Picoplankton were rapid initial respondents to the changing conditions with pigment markers showing an abrupt 4-fold increase in proportion but this increase was not sustained post-storm. 19’-HEX, a chemotaxonomic marker for prymnesiophytes, was the dominant accessory pigment pre- and post-storm with concentrations of 48-435 ng L-1, and represented 44% of total carotenoid concentrations. Accompanying scanning electron microscopy results support the pigment-based analysis but also provide detailed insight into the nano- and microplankton communities, which proved to be highly variable between pre-storm and post-storm sampling periods. Nanoplankton remained the dominant size class pre- and post-storm but the microplankton proportion peaked during the period of maximum nutrient and chlorophyll concentrations. Classic descriptions of autumn blooms resulting from storm driven eutrophication events promoting phytoplankton growth in surface waters should be tempered with greater understanding of the role of storm driven vertical reorganization of the water column and of resident phytoplankton communities. Crucially, in this case we observed no change in integrated chlorophyll, particulate organic carbon or biogenic silica concentrations despite also observing a ∼50% increase in surface chlorophyll concentrations which indicated that the surface enhancement in chlorophyll concentrations was most likely fed from below rather than resulting from in situ growth. Though not measured directly there was no evidence of enhanced export fluxes associated with this storm. These observations have implications for the growing practice of using chlorophyll fluorescence from remote platforms to determine ocean productivity late in the annual productivity period and in response to storm mixing

Mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M/PCK2), phosphoglycerate dehydrogenase (PHGDH) and muscle cell growth

Our group reported upregulation of a novel group of genes was associated with beta-adrenergic agonist (BA)-induced muscle hypertrophy in pigs. The aim of this PhD was to investigate the expression of these genes, and particularly the role of mitochondrial phosphoenolpyruvate carboxykinase (PEPCK-M/PCK2) and phosphoglycerate dehydrogenase (PHGDH), in muscle cell growth. A significant (p<0.01) increase in mRNA transcript abundance was detected at day 2 of differentiation in C2C12 cells for PEPCK-M, PHGDH, phosphoserine aminotransferase-1, phosphoserine phosphatase, asparagine synthetase, sestrin-2 and activating transcription factor-5. This novel peak coincided with the peak in myogenin mRNA, connecting these genes with a crucial point of myogenic differentiation. Hypertrophy was induced in C2C12 myotubes treated with dibutyryl-cAMP (dbcAMP), mimicking the BA response in vivo, however mRNA expression of these genes were unaffected. The porcine myosin heavy chain (MyHC)-IIB promoter-reporter C2C12 cell assay demonstrated similar in vivo responses to known anabolic and catabolic agents. Thus, C2C12 cells were utilised to determine the role of PEPCK-M and PHGDH in myogenic differentiation. Firstly, C2C12 cells were treated with a PEPCK inhibitor, 3-Mercaptopicolinic acid (3-MPA). 3-MPA induced differentiation, resulting in a hypertrophic response comparable to dbcAMP treatment. However, it was unclear whether 3-MPA inhibited PEPCK-M enzyme activity as 3-MPA interfered with the in vitro assay. Next, C2C12 cells were transfected with either PCK2 or PHGDH overexpression construct. No obvious phenotype was observed, but PHGDH and PEPCK-M overexpression both increased MyHC-IIB mRNA. The reoccurring induction of the same group of genes along with MyHC-IIB supports the hypothesis that co-ordinated upregulation of these genes may drive hypertrophic growth. To conclude, PEPCK-M, along with other genes upregulated with BA-induced hypertrophy and C2C12 differentiation, show co-ordinate regulation in times of high biosynthetic demand. PEPCK-M appears to sit at an intersection that allows metabolic flux to be largely altered by diverting intermediates during energy metabolism

Multi-Shell Hybrid Diffusion Imaging (HYDI) at 7 Tesla in TgF344-AD Transgenic Alzheimer Rats

Diffusion weighted imaging (DWI) is widely used to study microstructural characteristics of the brain. Diffusion tensor imaging (DTI) and high-angular resolution imaging (HARDI) are frequently used in radiology and neuroscience research but can be limited in describing the signal behavior in composite nerve fiber structures. Here, we developed and assessed the benefit of a comprehensive diffusion encoding scheme, known as hybrid diffusion imaging (HYDI), composed of 300 DWI volumes acquired at 7-Tesla with diffusion weightings at b = 1000, 3000, 4000, 8000 and 12000 s/mm^2 and applied it in transgenic Alzheimer rats (line TgF344-AD) that model the full clinico-pathological spectrum of the human disease. We studied and visualized the effects of the multiple concentric “shells” when computing three distinct anisotropy maps–fractional anisotropy (FA), generalized fractional anisotropy (GFA) and normalized quantitative anisotropy (NQA). We tested the added value of the multi-shell q-space sampling scheme, when reconstructing neural pathways using mathematical frameworks from DTI and q-ball imaging (QBI). We show a range of properties of HYDI, including lower apparent anisotropy when using high b-value shells in DTI-based reconstructions, and increases in apparent anisotropy in QBI-based reconstructions. Regardless of the reconstruction scheme, HYDI improves FA-, GFA- and NQA-aided tractography. HYDI may be valuable in human connectome projects and clinical research, as well as magnetic resonance research in experimental animals

Particle Dynamics in a Mass-Conserving Coalescence Process

We consider a fully asymmetric one-dimensional model with mass-conserving coalescence. Particles of unit mass enter at one edge of the chain and coalescence while performing a biased random walk towards the other edge where they exit. The conserved particle mass acts as a passive scalar in the reaction process $A+A\to A$, and allows an exact mapping to a restricted ballistic surface deposition model for which exact results exist. In particular, the mass- mass correlation function is exactly known. These results complement earlier exact results for the $A+A\to A$ process without mass. We introduce a comprehensive scaling theory for this process. The exact anaytical and numerical results confirm its validity.Comment: 5 pages, 6 figure

Memories of Parent Behaviors and Adult Attachment in Childhood Cancer Survivors

PURPOSE: Childhood cancer is stressful for the entire family. Preoccupation and anxiety surrounding the child's illness may result in parents of children with cancer being overprotective or less emotionally responsive toward their children. Such parenting in response to a negative life event like childhood cancer may cause survivors to be more insecurely attached than healthy peers, which could have downstream effects on survivors' romantic relationships later in life. Therefore, we examined survivors' perspectives on parent behaviors, adult attachment, and marital status among adult survivors of childhood cancer relative to controls. METHODS: One hundred forty-nine young adult survivors and 149 matched controls (Mage = 28, range 20-40) indicated their relationship status (single vs. partnered) and completed standardized questionnaires assessing memories of upbringing (warmth, overprotection, rejection) and adult attachment (avoidance, anxiety). RESULTS: Adult survivors of childhood cancer remembered mothers and fathers as emotionally warmer (d = 0.53/0.30), and mothers as less rejecting than controls (d = 0.30). Adult attachment was overall similar between survivors and controls, but partnered survivors reported particularly low attachment-related anxiety. Childhood cancer was related to higher mother and father warmth, which were associated with lower attachment-related avoidance and in turn with a greater likelihood of being in a relationship. CONCLUSION: Adult childhood cancer survivors did not remember their parents as overprotective, but reported more positive parenting relative to controls; and similar adult attachment and relationship status. The results were unexpected, but offer novel insights for future prospective studies, which are necessary to better understand psychosocial late effects of childhood cancer

A new testudinoid turtle from the middle to late Eocene of Vietnam

Testudinoidea is a major clade of turtles that has colonized different ecological environments across the globe throughout the Tertiary. Aquatic testudinoids have a particularly rich fossil record in the Tertiary of the northern hemisphere, but little is known about the evolutionary history of the group, as the phylogenetic relationships of most fossils have not been established with confidence, in part due to high levels of homoplasy and polymorphism.Methods: We here focus on describing a sample of 30 testudinoid shells, belonging to a single population that was collected from lake sediments from the middle to late Eocene (35–39 Ma) Na Duong Formation in Vietnam. The phylogenetic placement of this new material is investigated by integrating it and 11 other species of putative geoemydids from the Eocene and Oligocene to a recently published matrix of geoemydid turtles, that embraces the use of polymorphic characters, and then running a total-evidence analysis.Results: The new material is highly polymorphic, but can be inferred with confidence to be a new taxon, Banhxeochelys trani gen. et sp. nov. It shares morphological similarities with other southeastern Asian testudinoids, Isometremys lacuna and Guangdongemys pingi, but is placed phylogenetically at the base of Pan-Testuguria when fossils are included in the analysis, or as a stem geoemydid when other fossils are deactivated from the matrix. The vast majority of other putative fossil geoemydids are placed at the base of Pan-Testuguria as well.Discussion: The phylogenetic placement of fossil testudinoids used in the analysis is discussed individually and each species compared to Banhxeochelys trani gen. et sp. nov. The high levels of polymorphism observed in the new taxon is discussed in terms of ontogenetic and random variability. This is the first time that a large sample of fossil testudinoids has its morphological variation described in detail