B1: Geology of the Bald Mountain-Saddleback Wind Range, West-Central Maine

Guidebook for field trips in Western Maine and Northern New Hampshire: New England Intercollegiate Geological Conference, p. 119-134

Impurity effects in few-electron quantum dots: Incipient Wigner molecule regime

Numerically exact path-integral Monte Carlo data are presented for $N\leq 10$ strongly interacting electrons confined in a 2D parabolic quantum dot, including a defect to break rotational symmetry. Low densities are studied, where an incipient Wigner molecule forms. A single impurity is found to cause drastic effects: (1) The standard shell-filling sequence with magic numbers $N=4,6,9$, corresponding to peaks in the addition energy $\Delta(N)$, is destroyed, with a new peak at N=8, (2) spin gaps decrease, (3) for N=8, sub-Hund's rule spin S=0 is induced, and (4) spatial ordering of the electrons becomes rather sensitive to spin. We also comment on the recently observed bunching phenomenon.Comment: 7 pages, 1 table, 4 figures, accepted for publication in Europhysics Letter

Transmembrane ion transport by polyphosphate/poly-(R)-3-hydroxybutyrate complexes

Inorganic polyphosphates (polyPs) and poly-(R)-3-hydroxybutyrates (PHB) are simple linear polymers that are found in a wide variety of organisms, ranging from the most primitive to the most highly evolved Polyphosphates attract and select for cations by charge. PolyPs are linear chains of tetrahedral phosphate residues linked through common oxygen atoms by phosphoanhydride bonds Poly-(R)-3-hydroxybutyrates (PHBs) solvate cations. PolyP chains can form a framework of sufficient length to cross the bilayer, attract cations, select for divalent over monovalent cations and, in response to voltage or concentration gradients, move cations along its backbone. However, their high charge density creates a strong electrostatic barrier to penetrating a lipid bilayer. Also, polyPs do not distinguish among cations of the same charge by differences in size or coordination geometry. In order to form effective and selective cation transporters, polyPs must associate with amphiphilic REVIEW 0006-2979/00/6503-0280$25.00 ©2000 MAIK Nauka / Interperiodica Biochemistry (Moscow), Vol. 65, No. 3, 2000, pp. 280-295. Translated from Biokhimiya, Vol. 65, No. 3, 2000, pp. 335-352. Original Russian Text Copyright © 2000 AbstractTransmembrane ion transport, a critical process in providing energy for cell functions, is carried out by poreforming macromolecules capable of discriminating among very similar ions and responding to changes in membrane potential. It is widely regarded that ion channels are exclusively proteins, relatively late arrivals in cell evolution. Here we discuss the formation of ion-selective, voltage-activated channels by complexes of two simple homopolymers, namely, inorganic polyphosphates (polyPs) and poly-(R)-3-hydroxybutyrates (PHBs), derived from phosphate and acetate, respectively. Each has unique molecular characteristics that facilitate ion selection, solvation, and transport. Complexes of the two polymers, isolated from bacterial plasma membranes or prepared from the synthetic polymers, form voltage-dependent, Ca 2+ -selective channels in planar lipid bilayers that are selective for divalent over monovalent cations, permeant to Ca 2+ , Sr 2+ , and Ba 2+ , and blocked by transition metal cations in a concentration-dependent manner. Recently, both polyP and PHB have been found to be components of ion-conducting proteins: namely, the human erythrocyte Ca 2+ -ATPase pump and the Streptomyces lividans potassium channel. The contribution of polyP and PHB to ion selection and/or transport in these proteins is yet unknown, but their presence gives rise to the hypothesis that these and other ion transporters are supramolecular structures in which proteins, polyP, and PHB cooperate in forming well-regulated and specific cation transfer systems

Regional geochemical variations in a metamorphosed black shale: a reconnaissance study of the Silurian Smalls Falls Formation, Maine, USA

A reconnaissance geochemical study of 21 samples of sulphidic black phyllite and schist from the Silurian Smalls Falls Formation in Maine was undertaken in order to evaluate compositional changes during regional metamorphism. These samples represent variably metamorphosed black shale. Analyzed samples come from the chlorite zone in northern Maine and the biotite, garnet, and staurolite-andalusite zones in west-central Maine. Strata of the Smalls Falls Formation are distinctive in containing abundant pyrite and/or pyrrhotite (total S = 1.2–9.7 wt%), but only minor organic matter or graphite (TOC = 0.43–1.85 wt%); TOC/S ratios are uniformly low (average = 0.37 ± 0.22). Median enrichment factors were calculated for each element by normalizing the concentration to Ti in each sample to the Ti-normalized median composition of global black shale. In the chlorite zone, moderate to large decreases in enrichment factors (-23.1 to -49.8%) are evident for V, Cr, Cu, Ni, Zn, Pb, Sb, and U, attributed here to various factors during sedimentation plus variable element mobility during diagenesis. With increasing metamorphic grade (biotite through staurolite-andalusite zones), systematic small to extreme decreases (-14.5 to -99.0%) were found for Ba, Sb, Au, and U, together with less-systematic moderate to large decreases (-35.4 to -61.1%) for V and As. Molybdenum shows an extreme decrease (-94.7%) from the garnet to staurolite-andalusite zones. Excluding Ba, these results are interpreted to mainly reflect mobility of trace elements during pyrite recrystallization, and during the metamorphic transformations of organic matter to graphite and of pyrite to pyrrhotite. Moderate to large increases for Rb (+28.1 to +61.5%) and Th (+39.1 to +47.3%) from the biotite to staurolite-andalusite zones likely record the introduction of alkalis and mass loss, respectively, during metamorphism. Three samples from one site in the garnet zone differ in having anomalously high Fe/Al and low La/Yb ratios, attributed here to epigenetic formation of pyrite and related leaching of light rare earth elements during syn-metamorphic, channelized fluid flow.Geologic and geochemical data indicate that strata of the Smalls Falls Formation were deposited during an interval of anoxia on the northwestern flank of the Central Maine Basin, for which detrital sources included an evolved continental arc. Onset of anoxia coincided with deposition of the Mayflower Hill Formation of the Vassalboro Group, on the basin’s southeastern flank, related to emergence of the Brunswick subduction complex. We suggest that this emergence played a role in promoting both lateral and vertical circulation changes, nutrient loading, and deoxygenation through subsequent basin closure that culminated with Acadian deformation and metamorphism. Based on the relatively high contents of total sulphur present in our Smalls Falls samples, sediments in the Black Sea represent the only known plausible candidate among those in modern suboxic to euxinic basins

A2: Smalls Falls Revisted: A Journey Through a Paleozoic Sedimentary Basin

Guidebook for field trips in Western Maine and Northern New Hampshire: New England Intercollegiate Geological Conference, p. 35-60

Quantification of Hair Cortisol Concentration in Common Marmosets (\u3cem\u3eCallithrix jacchus\u3c/em\u3e) and Tufted Capuchins (\u3cem\u3eCebus apella\u3c/em\u3e)

Quantifying cortisol concentration in hair is a non-invasive biomarker of long-term hypothalamic-pituitary-adrenal (HPA) activation, and thus can provide important information on laboratory animal health. Marmosets (Callithrix jacchus) and capuchins (Cebus apella) are New World primates increasingly used in biomedical and neuroscience research, yet published hair cortisol concentrations for these species are limited. Review of the existing published hair cortisol values from marmosets reveals highly discrepant values and the use of variable techniques for hair collection, processing, and cortisol extraction. In this investigation we utilized a well-established, standardized protocol to extract and quantify cortisol from marmoset (n = 12) and capuchin (n = 4) hair. Shaved hair samples were collected from the upper thigh during scheduled exams and analyzed via methanol extraction and enzyme immunoassay. In marmosets, hair cortisol concentration ranged from 2710 – 6267 pg/mg and averaged 4070 ± 304 pg/mg. In capuchins, hair cortisol concentration ranged from 621 – 2089 pg/mg and averaged 1092 ± 338 pg/mg. Hair cortisol concentration was significantly different between marmosets and capuchins, with marmosets having higher concentrations than capuchins. The incorporation of hair cortisol analysis into research protocols provides a non-invasive measure of HPA axis activity over time, which offers insight into animal health. Utilization of standard protocols across laboratories is essential to obtaining valid measurements and allowing for valuable future cross-species comparisons

Cats with diabetes mellitus have diastolic dysfunction in the absence of structural heart disease

Diabetes mellitus (DM) can result in cardiovascular dysfunction and heart failure characterized by diastolic dysfunction with or without the presence of systolic dysfunction in people and laboratory animals. The objective of this prospective study was to determine if cats with newly diagnosed DM had myocardial dysfunction and, if present, whether it would progress if appropriate antidiabetic therapy was commenced. Thirty-two diabetic cats were enrolled and received baseline echocardiographic examination; of these, 15 cats were re-examined after 6 months. Ten healthy age- and weight-matched cats served as controls. Diabetic cats at diagnosis showed decreased diastolic, but not systolic function, when compared to healthy controls, with lower mitral inflow E wave (E) and E/E' than controls. After 6 months, E and E/IVRT' decreased further in diabetic cats compared to the baseline evaluation. After excluding cats whose DM was in remission at 6 months, insulin-dependent diabetic cats had lower E, E/A and E' than controls. When classifying diastolic function according to E/A and E'/A', there was shift towards impaired relaxation patterns at 6 months. All insulin-dependent diabetic cats at 6 months had abnormal diastolic function. These results indicate that DM has similar effects on diastolic function in feline and human diabetics. The dysfunction seemed to progress rather than to normalize after 6 months, despite antidiabetic therapy. In cats with pre-existing heart disease, the development of DM could represent an important additional health risk

Spatial structure of an individual Mn acceptor in GaAs

The wave function of a hole bound to an individual Mn acceptor in GaAs is spatially mapped by scanning tunneling microscopy at room temperature and an anisotropic, cross-like shape is observed. The spatial structure is compared with that from an envelope-function, effective mass model, and from a tight-binding model. This demonstrates that anisotropy arising from the cubic symmetry of the GaAs crystal produces the cross-like shape for the hole wave-function. Thus the coupling between Mn dopants in GaMnAs mediated by such holes will be highly anisotropic.Comment: 3 figures, submitted to PR

SNGuess: A method for the selection of young extragalactic transients

With a rapidly rising number of transients detected in astronomy, classification methods based on machine learning are increasingly being employed. Their goals are typically to obtain a definitive classification of transients, and for good performance they usually require the presence of a large set of observations. However, well-designed, targeted models can reach their classification goals with fewer computing resources. This paper presents SNGuess, a model designed to find young extragalactic nearby transients with high purity. SNGuess works with a set of features that can be efficiently calculated from astronomical alert data. Some of these features are static and associated with the alert metadata, while others must be calculated from the photometric observations contained in the alert. Most of the features are simple enough to be obtained or to be calculated already at the early stages in the lifetime of a transient after its detection. We calculate these features for a set of labeled public alert data obtained over a time span of 15 months from the Zwicky Transient Facility (ZTF). The core model of SNGuess consists of an ensemble of decision trees, which are trained via gradient boosting. Approximately 88% of the candidates suggested by SNGuess from a set of alerts from ZTF spanning from April 2020 to August 2021 were found to be true relevant supernovae (SNe). For alerts with bright detections, this number ranges between 92% and 98%. Since April 2020, transients identified by SNGuess as potential young SNe in the ZTF alert stream are being published to the Transient Name Server (TNS) under the AMPEL_ZTF_NEW group identifier. SNGuess scores for any transient observed by ZTF can be accessed via a web service. The source code of SNGuess is publicly available.Comment: 14 pages, 10 figures, Astronomy & Astrophysics (A&A), Forthcoming article, source code https://github.com/nmiranda/SNGues

Adrenocorticotropic hormone, but not trilostane, causes severe adrenal hemorrhage, vacuolization, and apoptosis in rats

Adrenal necrosis has been reported as a complication of trilostane application in dogs with hyperadrenocorticism. One suspicion was that necrosis results from the increase of adrenocorticotropic hormone (ACTH) during trilostane therapy. The aim of the current study was to assess the effects of ACTH and trilostane on adrenal glands of rats. For experiment 1, 36 rats were divided into 6 groups. Groups 1.1 to 1.4 received ACTH in different doses (60, 40, 20, and 10 μg/d) infused subcutaneously with osmotic minipumps for 16 wk. Group 1.5 received saline, and group 1.6 received no therapy. For experiment 2, 24 rats were divided into 3 groups. Group 2.1 and 2.2 received 5 and 50 mg/kg trilostane/d orally mixed into chocolate pudding for 16 wk. Eight control rats received pudding alone. At the end of the experiments, adrenal glands were assessed for necrosis by histology and immunohistochemistry; levels of endogenous ACTH and nucleosomes were assessed in the blood. Rats treated with 60 μg ACTH/d showed more hemorrhage and vacuolization and increased numbers of apoptotic cells in the adrenal glands than rats treated with 20 or 10 μg ACTH/d, trilostane, or control rats. Rats treated with 60 μg ACTH/d had a higher amount of nucleosomes in the blood compared with rats treated with 10 μg ACTH/d, trilostane, or saline. We conclude that in healthy rats ACTH, but not trilostane, causes adrenal degeneration in a dose-dependent manner. Results of this study support the hypothesis that adrenal gland lesions seen in trilostane-treated dogs are caused by ACTH and not by trilostane