A Climate Chronology

The most challenging of all endeavors in human history will likely be that of understanding the impact of our industrial and technological enterprises on the planet’s climate and ecosystems, and responding effectively to the threats posed by that impact. I began writing this chronology while developing a climate policy course at the University of Maine. It has grown substantially during the ensuing nine years, and continues to grow. By juxtaposing developments in climate science, U.S. policy, and international policy over the previous two centuries, I hope to give the reader new insights into where we have been, where we are now, and where we may be headed in this formidable endeavor. I welcome comments, and suggested additions to this evolving work. It will be updated every January

Research in Teaching and the Development of A Theory of Science Teaching

This paper outlines some of the significant aspects of research in teaching. Three phases can be distinguished in this research. They are the descriptive, the pragmatic and the eclectic-synthetic ones. The descriptive phase is characterized by the development of classroom observation schedules and the provision of sets of concepts permitting teachers and research workers to communicate about procedures. The categorization of behaviors has resulted in more attention being given to them. Hopefully, the vocabulary and concepts generated in the descriptive phase will not only aid in communicating ideas about teaching but will lead to a greater control over the process

Climate Policy 2015: Reports from the Congressional Trenches

The bipartisan commentary by Peter Mills and Sharon Tisher urges action in Congress to address the problem of climate change, and stems from interviews with Senator Susan Collins, Senator Angus King, and Congresswoman Chellie Pingree regarding their climate-related initiatives in 2015

Honors College_Honors 112 Class Screw this Virus _Alternate Final Exam Prompt

Email thread featuring messages from Melissa Ladenheim, Associate Dean, Honors College, University of Maine to the Provost Office and from Dr. Ladenheim to Sharon S. Tisher, Lecturer, School of Economics and Honors College, University of Maine regarding one optional prompt for Tisher\u27s take home exam in the two Honors 112 classes that incorporated COVID-19

Lanthanum permeability of tight junctions along the collecting duct of the rat

Lanthanum permeability of tight junctions along the collecting duct of the rat. The permeability of the tight junctions (zonulae occludentes) was evaluated along the entire length of the collecting duct of the rat using a lanthanum tracer technique. Nine rats with hereditary hypothalamic diabetes insipidus were studied using standard micropuncture and clearance techniques. Glomerular filtration rate (GFR) estimated from inulin clearance, urine and plasma osmolality (U/Posm) and urine flow rate (V) were determined in eight of nine animals. During either sustained diuresis (five animals) or vasopressin-induced antidiuresis (four animals), individual surface convolutions of distal convoluted tubules or early cortical collecting ducts were preserved for ultrastructural examination by intraluminal microperfusion with a glutaraldehyde-formaldehyde fixative followed by a second microperfusion with a lanthanum tracer. Mean GFR during diuresis was 6.31 ± SE 0.63 ml/min/kg of body wt and V = 797 ± SE 108 µl/min/kg or 13.6 ± SE 2.2% of the filtered load of water. After administration of exogenous vasopressin, V fell to 311 ± 157 µl/min/kg or 5.2 ± SE 3.8% of the filtered load of water and U/Posm rose from 0.658 ± SE 0.043 to 2.124 ± 0.454. Tight junctions of cortical and outer medullary segments of the collecting duct resisted lanthanum penetration. Tight junctions of the inner medullary and papillary segments of the collecting duct were freely permeable to lanthanum suggesting the presence of a paracellular shunt pathway for solute and water movement. The results were independent of the presence or absence of vasopressin. Physiological studies have previously demonstrated that cortical and outer medullary segments of the collecting duct have a low urea permeability while inner medullary and papillary segments of the collecting duct have a relatively high urea permeability. The possibility is suggested that urea movement across the inner medullary and papillary segments of the collecting duct may occur, at least in part, via a paracellular pathway formed by the nonoccluding tight junction and the lateral intercellular space.Perméabilité au lanthane des jonctions serrées le long du canal collecteur du rat. La perméabilité des jonctions serrées (zonulae occludentes) a été evaluée tout au long du canal collecteur du rat, au moyen d'une technique utilisant le lanthane comme traceur. Neuf rats atteints de diabète insipide hypothalamique héréditaire ont été étudiés au moyen des techniques habituelles de microponction et de clearance. La filtration glomérulaire (GFR) mesurée par la clearance de l'inuline, le rapport des osmolarités urine/plasma (U/Posm) et le débit urinaire (V) ont été obtenus chez huit des neuf animaux. Au cours de la diurèse entretenue (cinq animaux) ou de l'antidiurèse induite par la vasopressine (quatre animaux) des convolutions superficielles de tubes contournés distaux ou des canaux collecteurs précoces ont été préservés aux fins d'étude ultrastructurale par la microperfusion intraluminale d'un fixateur glutaraldéhyde-formaldéhyde suivie d'une deuxième microperfusion de lanthane. Le GFR moyen au cours de la diurèse était de 6,31 ± SE 0,63 ml/min/kg poids corporel et V = 797 ± SE 108 µl/min/kg ou 13,6 ± SE 2,2% de la charge d'eau filtrée. Après l'administration de vasopressine, V a diminué à 311 ± 157 µl/min/kg ou 5,2 ± SE 3,8 % de la charge d'eau filtrée et U/Posm est passé de 0,658 ± SE 0,043 à 2,124 ± 0,454. Les jonctions serrées des segments corticaux et médullaire externe des canaux collecteurs ont résisté à la pénétration de lanthane. Les jonctions serrées des segments médullaire interne et papillaire des canaux collecteurs ont été librement perméables au lanthane ce qui suggère une voie de shunt paracellulaire pour les mouvements d'ezu et de substances dissoutes. Les résultats sont indépendants de la présence ou de l'absence de vasopressine. Les études physiologiques antérieures ont montré que les segments corticaux et médullaires externes des canaux collecteurs ont une perméabilité faible pour l'urée, cependant que les segments médullaires internes et papillaires ont une perméabilité élevée. Il est suggéré que des mouvements d'urée à travers les segments médullaires internes et papillaires des canaux collecteurs puissent avoir lieu, au moins en partie, par une voie paracellulaire formée par les jonctions serrées non occlusives et l'espace intercellulaire latéral

Left Recursion in Parsing Expression Grammars

Parsing Expression Grammars (PEGs) are a formalism that can describe all deterministic context-free languages through a set of rules that specify a top-down parser for some language. PEGs are easy to use, and there are efficient implementations of PEG libraries in several programming languages. A frequently missed feature of PEGs is left recursion, which is commonly used in Context-Free Grammars (CFGs) to encode left-associative operations. We present a simple conservative extension to the semantics of PEGs that gives useful meaning to direct and indirect left-recursive rules, and show that our extensions make it easy to express left-recursive idioms from CFGs in PEGs, with similar results. We prove the conservativeness of these extensions, and also prove that they work with any left-recursive PEG. PEGs can also be compiled to programs in a low-level parsing machine. We present an extension to the semantics of the operations of this parsing machine that let it interpret left-recursive PEGs, and prove that this extension is correct with regards to our semantics for left-recursive PEGs.Comment: Extended version of the paper "Left Recursion in Parsing Expression Grammars", that was published on 2012 Brazilian Symposium on Programming Language

Regulation of manganese superoxide dismutase in glomerular epithelial cells: Mechanisms for interleukin 1 induction

Regulation of manganese superoxide dismutase in glomerular epithelial cells: Mechanisms for interleukin 1 induction. Reactive oxygen species have been implicated as mediators of tissue injury in glomerular inflammation. The expression of the antioxidant enzyme, manganese superoxide dismutase (MnSOD), was examined in primary cultures of rat glomerularepithelial cells (GEC) in response to inflammatory mediators. The results demonstrate that GEC respond to interleukin-1 (IL-1) and bacterial lipopolysaccharride (LPS) with an increase in MnSOD steady-state mRNA levels. The IL-1α-mediated induction of MnSOD mRNA levels was both time- and dose-dependent. Maximal levels, approximately 40-fold above controls, were observed at 12 hours with 2 ng/ml of IL-1α. MnSOD protein levels were also markedly elevated by IL-1α. The induction of MnSOD mRNA by IL-1α required de novo transcription as well as some degree of protein synthesis. To elucidate the potential intracellular signal that mediates IL-1α-dependent MnSOD expression, three classical signaling pathways were examined. We found no evidence that MnSOD induction by IL-lα is mediated by either the cyclooxygenase or lipoxygenase pathway or via activation of protein kinase C. Based on the presence of IL-lα in several forms of glomerular inflammation, the observed increase in MnSOD expression by this immunoregulatory cytokine must have an important role in the antioxidant defense of glomerular epithelial cells