Genes of tumor necrosis factors and their receptors and the primary open angle glaucoma in the population of Central Russia

To examine the association of genetic polymorphisms (-308)G/A TNFα, (+250)A/G Ltα, (+36)A/G TNFR1, (+1663) A/G TNFR2 with the development of primary open angle glaucoma (POAG) among people in Central Russi

Probabilistische Modellierung und Vorhersage der Standzeit und Zuverlässigkeit eines Fräswerkzeugs mittels der Bayesianischen Statistik [Probabilistic modeling and prediction of a milling tool life and reliability using bayesian statistics]

In diesem Artikel wird die probabilistische Modellierung und Vorhersage für die Standzeit und Zuverlässigkeit eines Fräswerkzeugs mittels der Bayesianischen Statistik beschrieben. Zur Entwicklung des probabilistischen Modells wird eine Markov-Chain-Monte-Carlo-Simulation (MCMC) auf das Taylor-Standzeit-Modell angewendet. Die A-priori-Wahrscheinlichkeitsverteilungen werden aus der Literaturrecherche ermittelt. Aus anschließenden Fräsversuchen werden ein Trainings- und ein Testdatensatz generiert. Die Versuche werden in einem Bereich der Schnittgeschwindigkeiten von 300 bis 400m/min durchgeführt. Die A-posteriori-Wahrscheinlichkeitsverteilungen werden unter Verwendung des Trainingssatzes berechnet. Mittels der trainierten A-posteriori-Wahrscheinlichkeitsverteilungen werden anschließend die Testdatensätze bei den Schnittgeschwindigkeiten von 300 bis 400m/min vorhergesagt. Es folgt ein Vergleich des probabilistischen Standzeitmodells mit den Testdatensätzen. Anschließend werden die A-posteriori-Verteilungen derWerkzeugstandzeit verwendet, um eine Zuverlässigkeitsanalyse unter Verwendung der Zuverlässigkeitsfunktion in Abhängigkeit der Schnittgeschwindigkeit durchzuführen. Es wird gezeigt, dass die Werkzeugstandzeit- und Zuverlässigkeitsfunktion die gemessenen Werkzeugstandzeiten innerhalb der Unsicherheitsintervalle mit einem maximalen Vorhersagefehler von 18% mit lediglich zwei Trainingsdatenpunkten vorhersagen können

Probabilistic prediction of cutting and ploughing forces using extended kienzle force model in orthogonal turning process

Probabilistic prediction of cutting and ploughing forces is performed by applying Bayesian inference to an extended Kienzle force model. Prior probabilities are established and posterior force predictions are completed. The results of the probabilistic force predictions are then verified using forces measured under other cutting conditions, as well as a simplified slip-line force model. Additionally, probabilistic simulation results are compared with the results of a non-linear least squares fitting technique to isolate the shearing and ploughing force components of the cutting force

U-Pb zircon age of volcaniclastic layers in Middle Triassic platform carbonates of the Austroalpine Silvretta nappe (Switzerland)

We present precise U-Pb age determinations from two volcaniclastic layers within Middle Triassic carbonates in the Upper Austroalpine Silvretta nappe near Davos (Switzerland). The two volcaniclastic layers were dated using annealing-leaching techniques and yielded ages of 240.91 ± 0.26 Ma (Prosanto Formation) and 239.89 ± 0.21 Ma (Altein Formation), respectively. The high resolution ages allow comparison of the Upper Austroalpine record of the Ducan with sections in the Southern Alps. The upper Prosanto Formation is, thus, equivalent to the middle part of the Buchenstein Formation (Middle Pietra Verde, Earliest Ladinian), and the Altein Formation is equivalent to the upper part of the Buchenstein Formation in the section with the Global boundary Stratotype Section and Point (GSSP) for the base of the Ladinian (Bagolino, northern Italy). This study demonstrates that we can use precise, accurate and carefully intercalibrated U-Pb zircon ages from volcaniclastic layers to infer the stratigraphic position of their host sediments on zone level. The older volcaniclastic layer (240.91 ± 0.26 Ma) allows a precise age determination (earliest Ladinian) for the marine vertebrate beds in the upper Prosanto Formation

High-resolution geochronology of the Coroccohuayco porphyry-skarn deposit, Peru: A rapid product of the Incaic orogeny

Precise and accurate determination of the timing and duration of ore-forming processes in porphyry systems is a fundamental step in understanding their genesis and placing them in a regional context. Here, we take advantage of the considerable improvements in the field of geochronology over the last decade to provide a robust geochronologic framework for hydrothermal and magmatic events in the Eocene Coroccohuayco porphyry-skarn Cu deposit, and the first robust dating of an ore system in the emerging Andahuaylas-Yauri batholith and metallogenic belt, southern Peru. This batholith and associated porphyry systems were emplaced during the Incaic orogeny, in a context of slab flattening, compression, exhumation, uplift, and the initiation of the bending of the Bolivian orocline. High-precision ages from early skarn (U-Pb, hydrothermal titanite) and later-stage mineralization (Re-Os, molybdenite) in the Coroccohuayco deposit are indistinguishable from each other and from available high-precision U-Pb zircon ages of the porphyries. All together, they indicate that the deposit was formed in less than 100 k.y. between 35.7 and 35.6 Ma. We also highlight a previously unrecognized pre-ore high-temperature hydrothermal event (U-Pb, hydrothermal titanite) that corresponds to the emplacement of a precursor gabbrodiorite complex at ca. 40.2 Ma. A new 40Ar/39Ar age at 26.6 Ma of a post-ore alkali basalt is interpreted as recording the initiation of slab roll-back following the flat slab episode and is therefore not related to the magmatic-hydrothermal system at Coroccohuayco. These data, together with structural measurements at the Coroccohuayco deposit and available regional data, suggest that the Coroccohuayco deposit was formed toward the end of Eocene arc magmatism, in a context of transpressional stress, intense erosion, and exhumation associated with Incaic orogeny. At the scale of the Tintaya ore district (which hosts the Coroccohuayco, Tintaya, and Antapaccay deposits), available data and a new molybdenite Re-Os age obtained for the Tintaya deposit suggest that mineralizing events were spatially focused and episodic over several millions of years, while a single economic deposit may have been formed within less than 100 k.y

Incremental growth of the Patagonian Torres del Paine laccolith over 90 k.y.

The Miocene Paine Granite in the Torres del Paine Intrusive Complex, southern Chile, is an extraordinary example of an upper crustal mafic and granitic intrusion. The granite intruded as a series of three sheets, each one underplating the previous sheet along the top of the basal Paine Mafic Complex. High-precision U/Pb geochronology on single zircons using isotope dilution-thermal ionization mass spectrometry yields distinct ages of 12.59 +/- 0.02 Ma and 12.50 +/- 0.02 Ma, respectively, for the first and last sheet of the laccolith. This age relationship is consistent with field observations. The zircon ages define a time frame of 90 +/- 40 k.y. for the emplacement of a >2000-m-thick granite laccollith. These precise U-Pb zircon ages permit identification of the pulses in a 20 k.y. range. The data obtained for the Paine Granite fill the gap between 100 k.y. and 100-1000 yr pulses described in the literature for crustal magma chambers

Precise U-Pb age constraints for end-Triassic mass extinction, its correlation to volcanism and Hettangian post-extinction recovery

New precise zircon U-Pb ages are proposed for the Triassic-Jurassic (Rhetian-Hettangian) and the Hettangian-Sinemurian boundaries, The ages were obtained by ID-TIMS dating of single chemical-abraded zircons from volcanic ash layers within the Pucara Group, Aramachay Formation in the Utcubamba valley, northern Peru. Ash layers situated between last and first occurrences of boundary-defining ammonites yielded Pb-206/U-238 ages of 201.58 +/- 0.17/0.28 Ma (95% c.l., uncertainties without/with decay constant errors, respectively) for the Triassic-Jurassic and of 199.53 +/- 0.19/0.29 Ma for the Hettangian-Sinemurian boundaries. The former is established on a tuff located 1 m above the last local occurrence of the topmost Triassic genus Choristoceras, and 5 m below the Hettangian genus Psiloceras. The latter sample was obtained from a tuff collected within the Badouxia canadensis beds. Our new ages document total duration of the Hettagian of no more than c. 2 m.y., which has fundamental implications for the interpretation and significance of the ammonite recovery after the topmost Triassic extinction. The U-Pb age is about 0.8 +/- 0.5% older than Ar-40-Ar-39 dates determined on flood basalts of the Central Atlantic Magmatic Province (CAMP). Given the widely accepted hypothesis that inaccuracies in the K-40 decay constants or physical constants create a similar bias between the two dating methods, our new U-Pb zircon age determination for the T/J boundary corroborates the hypothesis that the CAMP was emplaced at the same time and may be responsible for a major climatic turnover and mass extinction. The zircon Pb-206/U-238 age for the T/J boundary is marginally older than the North Mountain Basalt (Newark Supergroup, Nova Scotia, Canada), which has been dated at 201.27 +/- 0.06 Ma [Schoene et al., 2006. Geochim. Cosmochim. Acta 70, 426-445]. It will be important to look for older eruptions of the CAMP and date them precisely by U-Pb techniques while addressing all sources of systematic uncertainty to further test the hypothesis of volcanic induced climate change leading to extinction. Such high-precision, high-accuracy data will be instrumental for constraining the contemporaneity of geological events at a 100 kyr level. (C) 2007 Elsevier B.V. All rights reserved

Genes of tumor necrosis factors and their receptors and the primary open angle glaucoma in the population of Central Russia

To examine the association of genetic polymorphisms (-308)G/A TNFα, (+250)A/G Ltα, (+36)A/G TNFR1, (+1663) A/G TNFR2 with the development of primary open angle glaucoma (POAG) among people in Central Russi

Epicycloidal Versus Trochoidal Milling-Comparison of Cutting Force, Tool Tip Vibration, and Machining Cycle Time

AbstractAmong several strategies for high performance cutting, trochoidal milling is an efficient one for roughing process and reduces the cycle times significantly. For maximization of the efficiency and reducing the machining cycle time in the trochoidal milling, a novel tool path strategy, so- called, epicycloidal milling is developed. In this paper, mathematical model of the epicycloidal milling is presented. For the two mentioned strategies, comparison between cutting forces, tool tip vibrations, and machining cycle times are performed by four levels of machining experiments. To calculate the tool tip vibration, modal parameters of machine tool are achieved by system identification and then dynamic models of the machine spindle has been developed. It is observed that epicycloidal milling can improve machining cycle time, while the measured forces and calculated vibrations increased slightly