454 resultados para Bend
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Laurentide glaciation during the early Pleistocene (~970 ka) dammed the southeast-flowing West Branch of the Susquehanna River (WBSR), scouring bedrock and creating 100-km-long glacial Lake Lesley near the Great Bend at Muncy, Pennsylvania (Ramage et al., 1998). Local drill logs and well data indicate that subsequent paleo-outwash floods and modern fluvial processes have deposited as much as 30 meters of alluvium in this area, but little is known about the valley fill architecture and the bedrock-alluvium interface. By gaining a greater understanding of the bedrock-alluvium interface the project will not only supplement existing depth to bedrock information, but also provide information pertinent to the evolution of the Muncy Valley landscape. This project determined if variations in the thickness of the valley fill were detectable using micro-gravity techniques to map the bedrock-alluvium interface. The gravity method was deemed appropriate due to scale of the study area (~30 km2), ease of operation by a single person, and the available geophysical equipment. A LaCoste and Romberg Gravitron unit was used to collect gravitational field readings at 49 locations over 5 transects across the Muncy Creek and Susquehanna River valleys (approximately 30 km2), with at least two gravity base stations per transect. Precise latitude, longitude and ground surface elevation at each location were measured using an OPUS corrected Trimble RTK-GPS unit. Base stations were chosen based on ease of access due to the necessity of repeat measurements. Gravity measurement locations were selected and marked to provide easy access and repeat measurements. The gravimeter was returned to a base station within every two hours and a looping procedure was used to determine drift and maximize confidence in the gravity measurements. A two-minute calibration reading at each station was used to minimize any tares in the data. The Gravitron digitally recorded finite impulse response filtered gravity measurements every 20 seconds at each station. A measurement period of 15 minutes was used for each base station occupation and a minimum of 5 minutes at all other locations. Longer or multiple measurements were utilized at some sites if drift or other externalities (i.e. train or truck traffic) were effecting readings. Average, median, standard deviation and 95% confidence interval were calculated for each station. Tidal, drift, latitude, free-air, Bouguer and terrain corrections were then applied. The results show that the gravitational field decreases as alluvium thickness increases across the axes of the Susquehanna River and Muncy Creek valleys. However, the location of the gravity low does not correspond with the present-day location of the West Branch of the Susquehanna River (WBSR), suggesting that the WBSR may have been constrained along Bald Eagle Mountain by a glacial lobe originating from the Muncy Creek Valley to the northeast. Using a 3-D inversion model, the topography of the bedrock-alluvium interface was determined over the extent of the study area using a density contrast of -0.8 g/cm3. Our results are consistent with the bedrock geometry of the area, and provide a low-cost, non-invasive and efficient method for exploring the subsurface and for supplementing existing well data.
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During the lead-up to Montana second progressive era, Lee Metcalf and Forrest Anderson, along with others, kept the progressive flame lit in Montana. Metcalf’s political history is replete with close electoral wins because of his commitment to progressive ideals when the times were not always politically favorable for that. As State Legislator, MT Supreme Court Justice, Congressman and eventually as US Senator, Lee won races by as little as 55 votes because he stuck to his guns as a progressive. In Forrest Anderson’s career as a County Attorney, State Legislator, MT Supreme Court Justice and 12 years as MT Attorney General he was respected as a pragmatic practitioner of politics. But during that entire career leading up to his election as Governor, Forrest Anderson was also a stalwart supporter of the progressive agenda exemplified by FDR and the New Deal, which brought folks out of the Great Depression that was brought on by the bad policies of the GOP and big business. As MT’s second progressive period began in 1965, the first important election was Senator Metcalf’s successful re-election battle in 1966 with the sitting MT Governor, Tim Babcock. And the progressive express was really ignited by the election of Forrest Anderson as Governor in 1968 after 16 years of Republican Governors in MT. Gordon Bennett played a rather unique role, being a confidant of Metcalf and Anderson, both who respected his wide and varied experience, his intellect, and his roots in progressivism beginning with his formative years in the Red Corner of NE Montana. Working with Senator Metcalf and his team, including Brit Englund, Vic Reinemer, Peggy McLaughlin, Betty Davis and Jack Condon among others, Bennett helped shape the progressive message both in Washington DC and MT. Progressive labor and farm organizations, part of the progressive coalition, benefitted from Bennett’s advice and counsel and aided the Senator in his career including the huge challenge of having a sitting popular governor run against him for the Senate in 1966. Metcalf’s noted intern program produced a cadre of progressive leaders in Montana over the years. Most notably, Ron Richards transitioned from Metcalf Intern to Executive Secretary of the Montana Democratic Party (MDP) and assisted, along with Bennett, in the 1966 Metcalf-Babcock race in a big way. As Executive Secretary Richards was critical to the success of the MDP as a platform for Forrest Anderson’s general election run and win in 1968. After Forrest’s gubernatorial election, Richards became Executive Assistant (now called Chief of Staff) for Governor Anderson and also for Governor Thomas Judge. The Metcalf progressive strain, exemplified by many including Richards and Bennett, permeated Democratic politics during the second progressive era. So, too, did the coalition that supported Metcalf and his policies. The progressivism of the period of “In the Crucible of Change” was fired up by Lee Metcalf, Forrest Anderson and their supporters and coalitions, and Gordon Bennett was in the center of all of that, helping fire up the crucible, setting the stage for many policy advancements in both Washington DC and Montana. Gordon Bennett’s important role in the 1966 re-election of Senator Lee Metcalf and the 1968 election of Governor Forrest Anderson, as well as his wide experience in government and politics of that time allows him to provide us with an insider’s personal perspective of those races and other events at the beginning of the period of progressive change being documented “In the Crucible of Change,” as well as his personal insights into the larger political/policy picture of Montana. Gordon Bennett, a major and formative player “In the Crucible of Change,” was born in the far northeast town of Scobey, MT in 1922. He attended school in Scobey through the eighth grade and graduated from Helena High School. After attending Carroll College for two years, he received his BA in economics from Carleton College in Northfield, MN. During a brief stint on the east coast, his daily reading of the New York Times (“best newspaper in the world at that time … and now”) inspired him to pursue a career in journalism. He received his MA in Journalism from the University of Missouri and entered the field. As a reporter for the Great Falls Tribune under the ownership and management of the Warden Family, he observed and competed with the rigid control of Montana’s press by the Anaconda Company (the Great Falls Tribune was the only large newspaper in Montana NOT owned by ACM). Following his intellectual curiosity and his philosophical bend, he attended a number of Farm-Labor Institutes which he credits with motivating him to pursue solutions to economic and social woes through the law. In 1956, at the age of 34, he received his Juris Doctorate degree from the Georgetown University Law Center in Washington, DC. Bennett’s varied career included eighteen years as a farmer, four years in the US Army during WWII (1942-46), two years as Assistant MT Attorney General (1957-59) with Forrest Anderson, three years in private practice in Glasgow (1959-61), two years as Associate Solicitor in the Department of Interior in Washington, DC (1961-62), and private law practice in Helena from 1962 to 1969. While in Helena he was an unsuccessful candidate for the Montana Supreme Court (1962) and cemented his previous relationships with Attorney General Forrest Anderson and US Senator Lee Metcalf. Bennett modestly refuses to accept the title of Campaign Manager for either Lee Metcalf (1966 re-election over the challenger, MT Republican Governor Tim Babcock) or Forrest Anderson (his 1968 election as Governor), saying that “they ran their campaigns … we were only there to help.” But he has been generally recognized as having filled that critical role in both of those critical elections. After Governor Anderson’s election in 1968, Bennett was appointed Director of the MT Unemployment Compensation Commission, a position from where he could be a close advisor and confidant of the new Governor. In 1971, Governor Anderson appointed him Judge in the most important jurisdiction in Montana, the 1st Judicial District in Helena, a position he held for seventeen years (1971-88). Upon stepping down from his judgeship, for twenty years (1988-2008) he was a law instructor, mediator and arbitrator. He currently resides in Helena with his wife, Norma Tirrell, former newspaper reporter and researcher/writer. Bennett has two adult children and four grandchildren.
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The geosciences are often characterized as a visuospatial field - that is, one in which success depends upon the ability to mentally manipulate, rotate, project, and bend objects. To what extent is the assumption of strong spatial visualization skills among geoscientists correct? This talk will discuss two studies that investigated geoscience expert and novice spatial visualization, both in laboratory experiments and in a novel field study.
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Liquid crystals (LCs) represent a challenging group of materials for direct transmission electron microscopy (TEM) studies due to the complications in specimen preparation and the severe radiation damage. In this paper, we summarize a series of specimen preparation methods, including thin film and cryo-sectioning approaches, as a comprehensive toolset enabling high-resolution direct cryo-TEM observation of a broad range of LCs. We also present comparative analysis using cryo-TEM and replica freeze-fracture TEM on both thermotropic and lyotropic LCs. In addition to the revisits of previous practices, some new concepts are introduced, e.g., suspended thermotropic LC thin films, combined high-pressure freezing and cryo-sectioning of lyotropic LCs, and the complementary applications of direct TEM and indirect replica TEM techniques. The significance of subnanometer resolution cryo-TEM observation is demonstrated in a few important issues in LC studies, including providing direct evidences for the existence of nanoscale smectic domains in nematic bent-core thermotropic LCs, comprehensive understanding of the twist-bend nematic phase, and probing the packing of columnar aggregates in lyotropic chromonic LCs. Direct TEM observation opens ways to a variety of TEM techniques, suggesting that TEM (replica, cryo, and in situ techniques), in general, may be a promising part of the solution to the lack of effective structural probe at the molecular scale in LC studies. Microsc. Res. Tech. 77:754-772, 2014. © 2014 Wiley Periodicals, Inc.
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INTRODUCTION 17β-estradiol (E2) has been found to induce vasodilation in the cardiovascular system and at physiological levels, resulting in prevention of cerebral vasospasm following subarachnoid hemorrhage (SAH) in animal models. The goal of this study was to analyze the cellular mechanism of nitric oxide (NO) production and its relation to E2, in vitro in brain and peripheral endothelial cells. METHODS Human umbilical endothelial cells (HUVEC) and brain endothelial cells (bEnd.3) were treated with estradiol (E2, 0.1, 10, 100, and 1,000 nM), and supernatant was collected at 0, 5, 15, 30, 60, and 120 min for nitric oxide metabolome (nitrite, NO₂) measurements. Cells were also treated with E2 in the presence of 1400W, a potent eNOS inhibitor, and ICI, an antagonist of estradiol receptors (ERs). Effects of E2 on eNOS protein expression were assessed with Western blot analysis. RESULTS E2 significantly increased NO2 levels irrespective of its concentration in both cell lines by 35 % and 42 % (p < 0.05). The addition of an E2 antagonist, ICI (10 μM), prevented the E2-induced increases in NO2 levels (11 % p > 0.05). The combination of E2 (10 nM) and a NOS inhibitor (1400W, 5 μM) inhibited NO2 increases in addition (4 %, p > 0.05). E2 induced increases in eNOS protein levels and phosphorylated eNOS (eNOS(p)). CONCLUSIONS This study indicates that E2 induces NO level increases in cerebral and peripheral endothelial cells in vitro via eNOS activation and through E2 receptor-mediated mechanisms. Further in vivo studies are warranted to evaluate the therapeutic value of estrogen for the treatment of SAH-induced vasospasm.
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OBJECTIVE To determine the biomechanical effect of an intervertebral spacer on construct stiffness in a PVC model and cadaveric canine cervical vertebral columns stabilized with monocortical screws/polymethylmethacrylate (PMMA). STUDY DESIGN Biomechanical study. SAMPLE POPULATION PVC pipe; cadaveric canine vertebral columns. METHODS PVC model-PVC pipe was used to create a gap model mimicking vertebral endplate orientation and disk space width of large-breed canine cervical vertebrae; 6 models had a 4-mm gap with no spacer (PVC group 1); 6 had a PVC pipe ring spacer filling the gap (PCV group 2). Animals-large breed cadaveric canine cervical vertebral columns (C2-C7) from skeletally mature dogs without (cadaveric group 1, n = 6, historical data) and with an intervertebral disk spacer (cadaveric group 2, n = 6) were used. All PVC models and cadaver specimens were instrumented with monocortical titanium screws/PMMA. Stiffness of the 2 PVC groups was compared in extension, flexion, and lateral bending using non-destructive 4-point bend testing. Stiffness testing in all 3 directions was performed of the unaltered C4-C5 vertebral motion unit in cadaveric spines and repeated after placement of an intervertebral cortical allograft ring and instrumentation. Data were compared using a linear mixed model approach that also incorporated data from previously tested spines with the same screw/PMMA construct but without disk spacer (cadaveric group 1). RESULTS Addition of a spacer increased construct stiffness in both the PVC model (P < .001) and cadaveric vertebral columns (P < .001) compared to fixation without a spacer. CONCLUSIONS Addition of an intervertebral spacer significantly increased construct stiffness of monocortical screw/PMMA fixation.
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OBJECTIVE To compare biomechanical stiffness of cadaveric canine cervical spine constructs stabilized with bicortical stainless steel pins and polymethylmethacrylate (PMMA), monocortical stainless steel screws with PMMA, or monocortical titanium screws with PMMA. STUDY DESIGN Biomechanical cadaver study. ANIMALS Eighteen canine cervical vertebral columns (C2-C7) were collected from skeletally mature dogs (weighing 22-32 kg). METHODS Specimens were radiographed and examined by dual energy X-ray absorptiometry. Stiffness of the unaltered C4-C5 intervertebral motion unit was measured in extension, flexion and lateral bending using non-destructive 4-point bend testing. Specimens were then stabilized by (1) bicortical stainless steel pins/PMMA, (2) monocortical stainless steel screws/PMMA, or (3) monocortical titanium screws/PMMA. Mechanical testing was repeated and stiffness data from unaltered specimens and the 3 treatment groups were compared. RESULTS All 3 surgical methods significantly increased stiffness of the C4-C5 motion unit compared with the unaltered specimen (P < .001 for all treatments), but stiffness was not significantly different among the 3 fixation groups (P = .578). CONCLUSIONS In this model, monocortical screw fixation (with stainless steel or titanium screws) was biomechanically equivalent to bicortical fixation.
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We analyzed cosmogenic nuclides in metal and/or silicate (primarily olivine) separated from the main-group pallasites Admire, Ahumada, Albin, Brahin, Brenham, Esquel, Finmarken, Glorieta Mountain, Huckitta, Imilac, Krasnojarsk, Marjalahti, Molong, Seymchan, South Bend, Springwater, and Thiel Mountains and from Eagle Station. The metal separates contained an olivine fraction which although small, <1 wt% in most cases, nonetheless contributes significantly to the budgets of some nuclides (e.g., up to 35% for Ne-21 and Al-26). A correction for olivine is therefore essential and was made using model calculations and/or empirical relations for the production rates of cosmogenic nuclides in iron meteoroids and/or measured elemental concentrations. Cosmic-ray exposure (CRE) ages for the metal phases of the main-group pallasites range from 7 to 180 Ma, but many of the ages cluster around a central peak near 100 Ma. These CRE ages suggest that the parent body of the main-group pallasites underwent a major break-up that produced most of the meteorites analyzed. The CRE age distribution for the pallasites overlaps only a small fraction of the distribution for the IIIAB iron meteorites. Most pallasites and IIIAB irons originated in different collisions, probably on different parent bodies; a few IIIABs and pallasites may have come out of the same collision but a firm conclusion requires further study. CRE ages calculated from noble gas and radionuclide data of the metal fraction are higher on average than the Ne-21 exposure ages obtained for the olivine samples. As the metal and olivine fractions were taken in most cases from different specimens, the depth-dependency of the production rate ratio Be-10/Ne-21 in metal, not accounted for in our calculations, may explain the difference.
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Briefwechsel zwischen Alice H. Maier und Max Horkheimer; 3 Briefe zwischen Adolf Sturmthal und Alice H. Maier, 1951; 1 Brief von Alice H. Maier an Hattie Ross, 25.09.1951; 1 Brief an Franz Neumann von Alice H. Maier, 20.08.1951; 1 Brief von Alice H. Maier an Friede Fromm-Reichmann, 20.08.1951; 1 Brief an Leo Löwenthal von M. von Medelssohn, 13.08.1951; 1 Brief an The New York Academy of Science von Alice H. Maier, 20.03.1951; 1 Brief von dem Lee Travel Service (New York) an Max Horkheimer, 09.08.1948; 1 Brief an Max Horkheimer von Walter Hallstein, 02.07.1948; 1 Brief von E. Stein an Max Horkheimer, 26.06.1948; 2 Briefe zwischen Alice H. Maier und Gaby Onderwijzer, 1947; 1 Brief an Alfred Haas von Emmy Henne, 01.04.1955; 11 Briefe zwischen Emmy Henne und Alice H. Maier, 1954 - 1955; 2 Briefe zwischen Max Horkheimer und Morris L. Ernst, Oktober 1955; 1 Brief an Alfred Haas und Fritz Moses von Emmy Henne, 01.04.1955; 1 Brief an Alice H. Maier von Alfred Haas und Fritz Moses, 25.10.1954; 1 Brief an das Barbison Plaza Hotel (New York) von Alice H. Maier, 10.02.1955; 4 Briefe von dem Institut für Sozialforshung (Fankfurt am Main) an die Social Studies Association (New York), 1952 - 1954; 2 Briefe und 8 Briefentwürfe von Max Horkheimer an Nicholas Jory, September 1954; 1 Brief und 2 Briefentwürfe an Stroock von Alice H. Maier, [1954]; 1 Brief an Max Horkheimer von L. A. Chamberlin, 16.08.1954; 1 Brief von A. P. Bersohn an Max Horkheimer, 17.08.1954; 1 Brief von Max Horkheimer an Jacob K. Javits, 07.08.1954; 1 Brief an The Ideal Book Shop (New York) von Alice H. Maier, 07.08.1954; 1 Brief von Lothar Wendt (Internist) an Max Horkheimer, 30.07.1954; 1 Brief von Max Horkheimer an Young, 16.07.1954; 1 Brief an R. B. Shipley von Chauncy D. Harris, 16.07.1954; 1 Brief von Chauncy D. Harris an Max Horkheimer, 28.05.1954; 3 Briefe zwischen Max Horkheimer und John J. McCloy, 1954; 1 Brief von John J. McCloy an Ruth Shipley, 12.07.1954; 4 Briefe zwischen Alice H. Maier und Volker von Hagen, 1954; 1 Brief an York Lucci von Alice H. Maier, 13.04.1954; 3 Briefe von Alice H. Maier an H. P. Edelman, 1954; 3 Briefe zwischen Diedrich Osmer und Alice H. Maier, 1953; 1 Brief an die Indiana University (South Bend) von Diedrich Osmer, 26.02.1953; 3 Briefe zwischen Alice H. Maier und Elizabeth C. Krueger, 1953; 2 Briefe zwischen David Melvin Raul und Alice H. Maier, 1952; 1 Brief von Frederick Wild an The American Quaterly (Mineapolis), 25.06.1952; 1 Brief an Alice H. Maier von David Riesman, 19.05.1952; 1 Brief und 1 Briefentwurf an Felix Weil von Alice H. Maier, 23.04.1952;
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Transcription factors often determine cell fate and tissue development. Chondrogenesis is the developmental process by which cartilages form. Recently, gene targeting studies have shown that two transcription factors, L-Sox5 and Sox6, play essential and redundant roles in chondrogenesis in vivo by converting precartilaginous cell condensations into cartilages. Both are highly similar High-Mobility-Group (HMG)-domain proteins that bind and subsequently bend DNA containing the 7bp HMG site (A/T)(A/T)CAA(A/T)G. They have no transactivation domain, but homo- and hetero-dimerize and preferentially bind DNA containing two HMG sites. They are thought to play an architectural role in transactivation by facilitating long-range DNA and protein interactions. To understand their molecular mechanism of action, we investigated how phasing, orientation, and spacing between HMG sites affect L-Sox5 and Sox6 DNA-binding. We determined that L-Sox5 and Sox6 dimers bind with high affinity to paired HMG sites in DNA rather than a single HMG site. Binding of paired sites is independent of DNA helical phasing, orientation of paired HMG sites and independent of distance up to 255 base pairs between sites. Mutational analysis demonstrated that binding of L-Sox5 and Sox6, independent of orientation of the sites, is critically dependent on the presence of paired HMG sites rather than one HMG site alone. Our data support a unique and novel model whereby L-Sox5 and Sox6 dimerize and bind DNA with pronounced spatial flexibility, possibly by a flexible hinge, and act as architectural transcription factors that bring distant DNA sites and proteins together to form higher order transcriptional complexes that are essential for the activation of their target genes in chondrogenesis. ^
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According to Wilson's (1963a, b) hypothesis, the volcanoes of the Hawaiian-Emperor Chain are formed as the Pacific lithospheric plate moves over a source of magma in the mantle. Morgan (1971, 1972) proposed that these "hot spots" resulted from "mantle plumes" that rise vertically from the core/mantle boundary and that are fixed about the deep mantle and rotating globe poles. The age of volcanoes increases with distance away from the recent "hot spot" beneath Kilauea volcano. The Hawaiian-Emperor bend indicates that the direction of motion of the Pacific plate changed about 40 m.y. ago.
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The Hawaiian-Emperor hotspot track has a prominent bend, which has served as the basis for the theory that the Hawaiian hotspot, fixed in the deep mantle, traced a change in plate motion. However, paleomagnetic and radiometric age data from samples recovered by ocean drilling define an age-progressive paleolatitude history, indicating that the Emperor Seamount trend was principally formed by the rapid motion (over 40 millimeters per year) of the Hawaiian hotspot plume during Late Cretaceous to early-Tertiary times (81 to 47 million years ago). Evidence for motion of the Hawaiian plume affects models of mantle convection and plate tectonics, changing our understanding of terrestrial dynamics.
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La presente investigación se enmarca en el proyecto mayor de nuestro plan de Doctorado en Letras. Luego de realizar una breve presentación de la obra de Tununa Mercado, procedemos a plantear nuestra hipótesis de trabajo: la de que a partir de la publicación de su libro La madriguera (1996) una ficción autobiográfica de infancia (categoría que involucra variables cuya fiabilidad han sido fuertemente sospechadas y cuestionadas por líneas teóricas desde el giro lingüístico en adelante) la autora funda un modo de réplica literaria (Avellaneda, 1983) al gobierno menemista y su ideología, bajo el procedimiento de una operación sustitutoria, desviada, en la que alude al gobierno de Juan Domingo Perón. Narrando y aludiendo a ese gobierno, desestabiliza las ficciones estatales oficiales (en especial el texto de lectura obligatoria La razón de mi vida, 1951) que sirvieron para legitimarlo y producir cohesión política y social, al tiempo que realiza una respuesta cultural de resistencia a la ideología y las prácticas sociales menemistas. Al mismo tiempo, construye un sujeto autobiográfico femenino, lo que involucra operaciones fuertemente innovadoras en orden de imponer una torsión en un género de fuerte tradición patriarcal en Occidente (Klein, 2001). Como toda ficción del origen, La madriguera no escapa a ciertos relatos míticos, fundantes de la identidad, en especial de carácter letrado, e interroga las categorías de la percepción, fundando una nueva sensibilidad y problematizando así el dominio de lo real. Esta es su forma de dar cuenta de los conflictos de fundamento social y no la que opera a partir de una doxa tranquilizadora y deformadora propia de los relatos estatales.