Geological transect across the Northwestern Himalaya in eastern Ladakh and Lahul (A model for the continental collision of India and Asia)

The detailed geological mapping and structural study of a complete transect across the northwestern Himalaya allow to describe the tectonic evolution of the north Indian continental margin during the Tethys ocean opening and the Himalayan Orogeny. The Late Paleozoic Tethys rifting is associated with several tectonomagmatic events. In Upper Lahul and SE Zanskar, this extensional phase is recorded by Lower Carboniferous synsedimentary transtensional faults, a Lower Permian stratigraphic unconformity, a Lower Permian granitic intrusion and middle Permian basaltic extrusions (Panjal Traps). In eastern Ladakh, a Permian listric normal fault is also related to this phase. The scarcity of synsedimentary faults and the gradual increase of the Permian syn-rift sediment thickness towards the NE suggest a flexural type margin. The collision of India and Asia is characterized by a succession of contrasting orogenic phases. South of the Suture Zone, the initiation of the SW vergent Nyimaling-Tsarap Nappe corresponds to an early phase of continental underthrusting. To the S, in Lahul, an opposite underthrusting within the Indian plate is recorded by the NE vergent Tandi Syncline. This structure is associated with the newly defined Shikar Beh Nappe, now partly eroded, which is responsible for the high grade (amphibolite facies) regional metamorphism of South Lahul. The main thrusting of the Nyimaling-Tsarap Nappe followed the formation of the Shikar Beh Nappe. The Nyimaling-Tsarap Nappe developed by ductile shear of the upper part of the subducted Indian continental margin and is responsible for the progressive regional metamorphism of SE Zanskar, reaching amphibolite facies below the frontal part of the nappe, near Sarchu. In Upper Lahul, the frontal parts of the Nyimaling-Tsarap and Shikar Beh nappes are separated by a zone of low grade metamorphic rocks (pumpellyite-actinolite facies to lower greenschist facies). At high structural level, the Nyimaling-Tsarap Nappe is characterized by imbricate structures, which grade into a large ductile shear zone with depth. The related crustal shortening is about 87 km. The root zone and the frontal part of this nappe have been subsequently affected by two zones of dextral transpression and underthrusting: the Nyimaling Shear Zone and the Sarchu Shear Zone. These shear zones are interpreted as consequences of the counterclockwise rotation of the continental underthrusting direction of India relative to Asia, which occurred some 45 and 36 Ma ago, according to plate tectonic models. Later, a phase of NE vergent `'backfolding'' developed on these two zones of dextral transpression, creating isoclinal folds in SE Zanskar and more open folds in the Nyimaling Dome and in the Indus Molasse sediments. During a late stage of the Himalayan Orogeny, the frontal part of the Nyimaling-Tsarap Nappe underwent an extension of about 15 km. This phase is represented by two types of structures, responsible for the tectonic unroofing of the amphibolite facies rocks of the Sarchu area: the Sarchu high angle Normal Fault, cutting a first set of low angle normal faults, which have been created by reactivation of older thrust planes related to the Nyimaling-Tsarap Nappe.

Obesity and overweight associated with lower rates of colorectal cancer screening in Switzerland.

Screening for colorectal cancer (CRC) is associated with reduced CRC mortality, but low screening rates have been reported in several settings. The aim of the study was to assess predictors of low CRC screening in Switzerland. A retrospective cohort of a random sample of 940 patients aged 50-80 years followed for 2 years from four Swiss University primary care settings was used. Patients with illegal residency status and a history of CRC or colorectal polyps were excluded. We abstracted sociodemographic data of patients and physicians, patient health status, and indicators derived from RAND's Quality Assessment Tools from medical charts. We defined CRC screening as colonoscopy in the last 10 years, flexible sigmoidoscopy in the last 5 years, or fecal occult blood testing in the last 2 years. We used bivariate and multivariate logistic regression analyses. Of 940 patients (mean age 63.9 years, 42.7% women), 316 (33.6%) had undergone CRC screening. In multivariate analysis, birthplace in a country outside of Western Europe and North America [odds ratio (OR) 0.65, 95% confidence interval (CI) 0.45-0.97], male sex of the physician in charge (OR 0.67, 95% CI 0.50-0.91), BMI 25.0-29.9 kg/m (OR 0.66, CI 0.46-0.96) and at least 30.0 kg/m (OR 0.61, CI 0.40-0.90) were associated with lower CRC screening rates. Obesity, overweight, birthplace outside of Western Europe and North America, and male sex of the physician in charge were associated with lower CRC screening rates in Swiss University primary care settings. Physician perception of obesity and its impact on their recommendation for CRC screening might be a target for further research.

Lower thigh subcutaneous and higher visceral abdominal adipose tissue content both contribute to insulin resistance.

It is well known that visceral adipose tissue (VAT) is associated with insulin resistance (IR). Considerable debate remains concerning the potential positive effect of thigh subcutaneous adipose tissue (TSAT). Our objective was to observe whether VAT and TSAT are opposite, synergistic or additive for both peripheral and hepatic IR. Fifty-two volunteers (21 male/31 female) between 30 and 75 years old were recruited from the general population. All subjects were sedentary overweight or obese (mean BMI 33.0 ± 3.4 kg/m(2)). Insulin sensitivity was determined by a 4-h hyperinsulinemic-euglycemic clamp with stable isotope tracer dilution. Total body fat and lean body mass were determined by dual X-ray absorptiometry. Abdominal and mid-thigh adiposity was determined by computed tomography. VAT was negatively associated with peripheral insulin sensitivity, while TSAT, in contrast, was positively associated with peripheral insulin sensitivity. Subjects with a combination of low VAT and high TSAT had the highest insulin sensitivity, subjects with a combination of high VAT and low TSAT were the most insulin resistant. These associations remained significant after adjusting for age and gender. These data confirm that visceral excess abdominal adiposity is associated with IR across a range of middle-age to older men and women, and further suggest that higher thigh subcutaneous fat is favorably associated with better insulin sensitivity. This strongly suggests that these two distinct fat distribution phenotypes should both be considered in IR as important determinants of cardiometabolic risk.

Strong minimax lower bounds for learning

Minimax lower bounds for concept learning state, for example, thatfor each sample size $n$ and learning rule $g_n$, there exists a distributionof the observation $X$ and a concept $C$ to be learnt such that the expectederror of $g_n$ is at least a constant times $V/n$, where $V$ is the VC dimensionof the concept class. However, these bounds do not tell anything about therate of decrease of the error for a {\sl fixed} distribution--concept pair.\\In this paper we investigate minimax lower bounds in such a--stronger--sense.We show that for several natural $k$--parameter concept classes, includingthe class of linear halfspaces, the class of balls, the class of polyhedrawith a certain number of faces, and a class of neural networks, for any{\sl sequence} of learning rules $\{g_n\}$, there exists a fixed distributionof $X$ and a fixed concept $C$ such that the expected error is larger thana constant times $k/n$ for {\sl infinitely many n}. We also obtain suchstrong minimax lower bounds for the tail distribution of the probabilityof error, which extend the corresponding minimax lower bounds.

Minimax lower bounds for the two-armed bandit problem

We obtain minimax lower bounds on the regret for the classicaltwo--armed bandit problem. We provide a finite--sample minimax version of the well--known log $n$ asymptotic lower bound of Lai and Robbins. Also, in contrast to the log $n$ asymptotic results on the regret, we show that the minimax regret is achieved by mere random guessing under fairly mild conditions on the set of allowable configurations of the two arms. That is, we show that for {\sl every} allocation rule and for {\sl every} $n$, there is a configuration such that the regret at time $n$ is at least 1 -- $\epsilon$ times the regret of random guessing, where $\epsilon$ is any small positive constant.

Cooperative Lakes Area Monitoring Project-Lower Gar Lake, 2007

Water fact sheet for Iowa Department of Natural Resources and the Geological Bureau.

Step count is associated with lower nighttime systolic blood pressure and increased dipping.

BACKGROUND: Higher nighttime blood pressure (BP) and the loss of nocturnal dipping of BP are associated with an increased risk for cardiovascular events. However, the determinants of the loss of nocturnal BP dipping are only beginning to be understood. We investigated whether different indicators of physical activity were associated with the loss of nocturnal dipping of BP. METHODS: We conducted a cross-sectional study of 103 patients referred for 24-hour ambulatory monitoring of BP. We measured these patients' step count (SC), active energy expenditure (AEE), and total energy expenditure simultaneously, using actigraphs. RESULTS: In our study population of 103 patients, most of whom were hypertensive, SC and AEE were associated with nighttime systolic BP in univariate (SC, r = -0.28, P < 0.01; AEE, r = -0.20, P = 0.046) and multivariate linear regression analyses (SC, coefficient beta = -5.37, P < 0.001; AEE, coefficient beta = -0.24, P < 0.01). Step count was associated with both systolic (r = 0.23, P = 0.018) and diastolic (r = 0.20, P = 0.045) BP dipping. Nighttime systolic BP decreased progressively across the categories of sedentary, moderately active, and active participants (125mm Hg, 116mm Hg, 112mm Hg, respectively; P = 0.002). The degree of BP dipping of BP increased progressively across the same three categories of activity (respectively 8.9%, 14.6%, and 18.6%, P = 0.002, for systolic BP and respectively 12.8%, 18.1%, and 22.2%, P = 0.006, for diastolic BP). CONCLUSIONS: Step count is continuously associated with nighttime systolic BP and with the degree of BP dipping independently of 24-hour mean BP. The combined use of an actigraph for measuring indicators of physical activity and a device for 24-hour measurement of ambulatory BP may help identify patients at increased risk for cardiovascular events in whom increased physical activity toward higher target levels may be recommended.

Help For Lower Income Iowans With Medicare, 2007

If you have limited income and resources, the State of Iowa may pay some of your Medicare expenses. Programs paying these expenses are shown in the chart on page 2. To see if you might be eligible, answer the questions below.

Groundwater Availability Modeling: Lower Dakota Aquifer, 2008

This monthly report from the Iowa Department of Natural Resources is about the water quality management of Iowa's rivers, streams and lakes.

Late Proterozoic thrust tectonics, high-pressure metamorphism and Uranium mineralization in the domes area, Lufilian arc, northwestern Zambia

The following main lithostratigraphic units have been distinguished in the Domes Area. The Kibaran basement complex composed of gneisses, migmatites with amphibolite bands and metagranites is exposed in dome structures; metamorphic features of Kibaran age have been almost completely obliterated by extensive Lufilian reactivation. The post-Kibaran cover sequence is subdivided into the Lower Roan Group consisting of well-preserved quartzites with high Mg content, talc-bearing, extremely foliated schists intercalated with pseudo-conglomerates of tectonic origin and the Upper Roan Group including dolomitic marbles with rare stromatolites, metapelites and a sequence of detrital metasediments, with local volcano-sedimentary components and interlayered banded ironstones. The sediments of the Lower Roan Group are interpreted as continental to lagoonal-evaporitic deposits partly converted into the talc-kyanite + garnet assemblage characteristic of ``white schists''. The dolomites and metapelites of the Upper Roan Group are attributed to a carbonate platform sequence progressively subsiding under terrigenous deposits, whilst the detrital metasediments and BIF may be interpreted as a basinal sequence, probably deposited on oceanic crust grading laterally into marbles. Metagabbros and metabasalts are considered as remnants of an ocean-floor-type crustal unit probably related to small basins. Alkaline stocks of Silurian age intruded the post-Kibaran cover. Significant ancestral tectonic discontinuities promoted the development of a nappe pile that underwent high-pressure metamorphism during the Lufilian orogeny and all lithostratigraphic units. Rb-Sr and K-Ar and U-Pb data indicate an age of 700 Ma for the highest grade metamorphism and 500 Ma for blocking of the K-Ar and Rb-Sr system in micas, corresponding to the time when the temperature dropped below 350-degrees-400-degrees-C and to an age of about 400 Ma for the emplacement of hypabyssal syenitic bodies. A first phase of crustal shortening by decoupling of basement and cover slices along shallow shear zones has been recognized. Fluid-rich tectonic slabs of cover sediments were thus able to transport fluids into the anhydrous metamorphic basement or mafic units. During the subsequent metamorphic re-equilibration stage of high pressure, pre-existing thrusts horizons were converted into recrystallized mylonites. Due to uplift, rocks were re-equilibrated into assemblages compatible with lower pressures and slightly lower temperatures. This stage occurs under a decompressional (nearly adiabatic) regime, with P(fluid) almost-equal-to P(lithostatic). It is accompanied by metasomatic development of minerals, activated by injection of hot fluids. New or reactivated shear zones and mylonitic belts were the preferred conduits of fluids. The most evident regional-scale effect of these processes is the intense metasomatic scapolitization of formerly plagioclase-rich lithologies. Uraninite mineralization can probably be assigned to the beginning of the decompressional stage. A third regional deformation phase characterized by open folds and local foliation is not accompanied by significant growth of new minerals. However, pitchblende mineralization can be ascribed to this phase as late-stage, short-range remobilization of previously existing deposits. Finally, shallow alkaline massifs were emplaced when the level of the Domes Area now exposed was already subjected to exchange with meteoric circuits, activated by residual geothermal gradients generally related to intrusions or rifting. Most of the superficial U-showings with U-oxidation products were probably generated during this relatively recent phase.

Geoquímica das rochas magmáticas da Ilha Brava:implicações para a origem e variabilidade espaço-temporal do ponto quente de Cabo Verde

A Ilha Brava (64 km2) localiza-se no extremo oeste do alinhamento meridional do arquipélago de Cabo Verde, sendo constituída por três unidades vulcanoestratigráficas que testemunham uma história vulcânica de cerca de 3 Ma. Foi escolhida como objecto de estudo na tentativa de contribuir para a melhor compreensão da origem e local de residência de alguns dos componentes mantélicos, das relações genéticas entre magmas silicatados e carbonatíticos, dos processos de desgaseificação de magmas carbonatíticos e da origem do carbono neles contido, da variabilidade geoquímica espaço-temporal do ponto quente de Cabo Verde, e da profundidade de enraizamento da sua pluma mantélica. A Brava contrasta com as outras ilhas do arquipélago por definir dois grupos geoquímicos distintos. As amostras do Complexo Basal, sendo menos radiogénicas Sr e He e mais em Nd e Pb que a unidade mais recente, são idênticas às ilhas do norte e explicáveis pela mistura de um componente do tipo HIMU (crosta oceânica reciclada com 1.3 Ga) e manto inferior (3He/4He até 12.85 Ra), carreados para a “superfície” pela pluma mantélica. Tal como é usual nas ilhas do sul, a Unidade Superior sugere, em adição, o envolvimento de um componente com afinidade EM-1, aqui considerado representativo de fragmentos de litosfera subcontinental dispersos na astenosfera. Os carbonatitos definem dois grupos com assinaturas isotópicas semelhantes às das rochas silicatadas contemporâneas. Os calciocarbonatitos resultaram de imiscibilidade líquida produzindo magmas nefeliníticos e carbonatíticos, enquanto os magnesiocarbonatitos representam líquidos residuais após a fraccionação de calcite a partir de um magma carbonatítico. As muito baixas razões 4He/40Ar* (≈ 0.25) que caracterizam a fonte dos carbonatitos do Complexo Basal indicam uma evolução a partir de razões K/U muito mais elevadas que o conjunto dos reservatórios silicatados da Terra. Sendo estes valores, também incompatíveis com a reciclagem de componentes crostais, foram aqui interpretados como podendo reflectir a contribuição do “missing Ar reservoir” para a fonte mantélica dos carbonatitos.

Pre-Mesozoic Alpine basements - Their place in the European Paleozoic framework

Prior to their Alpine overprinting, most of the pre-Mesozoic basement areas in Alpine orogenic structures shared a complex evolution, starting with Neoproterozoic sediments that are thought to have received detrital input from both West and East Gondwanan cratonic sources. A subsequent Neoproterozoic-Cambrian active margin setting at the Gondwana margin was followed by a Cambrian-Ordovician rifting period, including an Ordovician cordillera-like active margin setting. During the Late Ordovician and Silurian periods, the future Alpine domains recorded crustal extension along the Gondwana margin, announcing the future opening of the Paleotethys oceanic domain. Most areas then underwent Variscan orogenic events, including continental subduction and collisions with Avalonian-type basement areas along Laurussia and the juxtaposition and the duplication of terrane assemblages during strike slip, accompanied by contemporaneous crustal shortening and the subduction of Paleotethys under Laurussia. Thereafter, the final Pangea assemblage underwent Triassic and Jurassic extension, followed by Tertiary shortening, and leading to the buildup of the Alpine mountain chain. Recent plate-tectonic reconstructions place the Alpine domains in their supposed initial Cambrian-Ordovician positions in the eastern part of the Gondwana margin, where a stronger interference with the Chinese blocks is proposed, at least from the Ordovician onward. For the Visean time of the Variscan continental collision, the distinction of the former tectonic lower-plate situation is traceable but becomes blurred through the subsequent oblique subduction of Paleotethys under Laurussia accompanied by large-scale strike slip. Since the Pennsylvanian, this global collisional scenario has been replaced by subsequent and ongoing shortening and strike slip under rising geothermal conditions, and all of this occurred before all these puzzle elements underwent the complex Alpine reorganization.