Stable oxygen and carbon isotopes of carbonates in lake sediments as a paleoflood proxy

Lake sediments are increasingly explored as reliable paleoflood archives. In addition to established flood proxies including detrital layer thickness, chemical composition, and grain size, we explore stable oxygen and carbon isotope data as paleoflood proxies for lakes in catchments with carbonate bedrock geology. In a case study from Lake Mondsee (Austria), we integrate high-resolution sediment trapping at a proximal and a distal location and stable isotope analyses of varved lake sediments to investigate flood-triggered detrital sediment flux. First, we demonstrate a relation between runoff, detrital sediment flux, and isotope values in the sediment trap record covering the period 2011–2013 CE including 22 events with daily (hourly) peak runoff ranging from 10 (24) m3 s−1 to 79 (110) m3 s−1. The three- to ten-fold lower flood-triggered detrital sediment deposition in the distal trap is well reflected by attenuated peaks in the stable isotope values of trapped sediments. Next, we show that all nine flood-triggered detrital layers deposited in a sediment record from 1988 to 2013 have elevated isotope values compared with endogenic calcite. In addition, even two runoff events that did not cause the deposition of visible detrital layers are distinguished by higher isotope values. Empirical thresholds in the isotope data allow estimation of magnitudes of the majority of floods, although in some cases flood magnitudes are overestimated because local effects can result in too-high isotope values. Hence we present a proof of concept for stable isotopes as reliable tool for reconstructing flood frequency and, although with some limitations, even for flood magnitudes

Оптимизация системы электроснабжения ФСО предприятия "Эрдэнэт"

В данной диссертации был проведен выбор схемы электроснабжения, класс номинального напряжения для системы электроснабжения предприятия. Выбран вариант системы как наиболее экономичный и предпочтительный в плане надежности и удобства эксплуатации. Выбраны сечения кабельных линий и проводок, а также защитные аппараты. Данные варианты проверены на соответствие условиям: допустимой перегрузки, допустимых потерь напряжения, механической прочности. Проверены режимы напряжения на электроприемниках, обеспечивающие наиболее экономичную их работу.In this thesis, a choice was made of the power supply scheme, the class of nominal voltage for the power supply system of the enterprise. The system variant is chosen as the most economical and preferred in terms of reliability and ease of use.According to the daily schedule of the full capacity of the enterprise, a variant of the capacity of the feeding transformers of the SFD was planned taking into account the systematic and post-emergency overloads.The sections of cable lines and postings, as well as protective apparatuses, have been selected. These options are tested for compliance with the conditions: permissible overload, allowable voltage loss, mechanical strength. The voltage regimes at the electric receivers are checked, which ensure their most economical operation

Foraminiferal isotope evidence of reduced nitrogen fixation in the ice age Atlantic Ocean

Fixed nitrogen (N) is a limiting algal nutrient in the low latitude ocean, and the oceanic N inventory has been suggested to increase during ice ages so as to lower atmospheric CO_2. In organic matter within planktonic foraminifera shells in Caribbean Sea sediments, the ^(15)N/^(14)N from the last ice age is higher than that from the current interglacial, indicating higher nitrate ^(15)N/^(14)N in the Caribbean thermocline. This and species-specific differences are best explained by less N fixation in the Atlantic during the last ice age. The fixation decrease was most likely a response to a known ice age reduction in ocean N loss, and it would have worked to balance the ocean N budget and to curb ice age-to-interglacial change in the N inventory

Lake Challa (Kenya/Tanzania) sediments as archive of climate and environmental variability in equatorial East Africa

Recently, an increasing number of climate records from low-latitude regions underscore the importance of tropical atmospheric processes in the global climate system. Nevertheless, the regional synchrony of temperature and humidity variations, as well as teleconnecting Mechanisms between high and low latitudes are still poorly understood.The EuroCLIMATE CHALLACEA project aims at providing a continuous high resolution multi-proxy record of temperature and moisture-balance variability in equatorial East Africa from the Last Glacial Maximum (25 ka BP) to the present.Lake Challa is located in Southern Kenya about 40 km east of Mt. Kilimanjaro at an altitude of 880 m a.s.l..The lake occupies a crater nearly two kilometres in diameter and has a surface area of 4.51 km2. This freshwater lake has a permanently stratified water column and its water budget is controlled by sub-surface in- and outflow. The sub-surface inflow derives mainly from percolation of precipitation falling in the montane forest zone, higher up on the mountain. The lacustrine deposits mainly consist of autochthonous components (organic matter, carbonate, and biogenic silica) and aeolian mineral inputs.The present study focuses on microfacies analyses and isotope measurements.Fine laminations are preserved almost continuosly in the upper part of the sediment record. Microfacies analyses revealed that the light/dark couplets represent true calcite varves. The darker layers consist of endogenic calcite precipitating in the dry season when water temperature was high and the lake was biological productive. The lighter layers reflect abundant diatoms frustules but also detrital sediments fluxes of organic and minorogenic matter. The varve chronology was established by repeated counting of varves in thin sections under a petrographic microscope.This record will be complemented by carbon and oxygen isotope measurements on the carbonate fraction of the sediments.Preliminary analyses on bulk carbonates highlighted the potential of these sediments for reconstructing past variations in temperature and precipitation.Stable isotope analyses (d18O and d13C) on bulk carbonates were carried out in the upper 5.3 m of the 22 m long profile where carbonates are present.However, the analysed samples contain different amounts of calcite and aragonite, which make it difficult to interpret the changes in stable isotope values.Therefore, for the work on isotopes, we will try to separate calcite and aragonite by sampling single homogeneous layers, chosen amongst the thickest ones. These records will possibly help reconstructing temperature changes, while changes in isotope values of aragonite will possibly be linked to changes in hydrological conditions of the lake.Finally, these data will contribute enhancing our knowledge about climate changes of highly sensitive climate region of the Mt. Kilimanjaro area

Climate change and equestrian empires in the Eastern Steppes: new insights from a high-resolution Lake Core in Central Mongolia

The repeated expansion of East Asian steppe cultures was a key driver of Eurasian history, forging new social, economic, and biological links across the continent. Climate has been suggested as important driver of these poorly understood cultural expansions, but paleo-climate records from the Mongolian Plateau often suffer from poor age control or ambiguous proxy interpretation. Here, we use a combination of geochemical analyses and comprehensive radiocarbon dating to establish the first robust and detailed record of paleo-hydrological conditions for Lake Telmen, Mongolia, covering the past ~4000 years. Our record shows that humid conditions coincided with solar minima, and hydrological modelling confirms the high sensitivity of the lake to paleo-climate changes. Careful comparisons with archaeological and historical records suggest that in the vast semi-arid grasslands of eastern Eurasia, solar minima led to reduced temperatures, less evaporation, and high biomass production, expanding the power base for pastoral economies and horse cavalry. Our findings suggest a crucial link between temperature dynamics in the Eastern Steppe and key social developments, such as the emergence of pastoral empires, and fuel concerns that global warming enhances water scarcity in the semi-arid regions of interior Eurasia.1. Introduction 2. Results 2.1 Sediment core chronology 2.2 Sedimentological and geochemical analyses 2.3 Isotope analyses, evaporation index (EI), and paleohydrology 3. Discussion 3.1 External forcing on the regional climate 3.2 Hydrological modelling 3.3 Climate impact on human history in Mongolia Method

The unexpectedly short Holocene Humid Period in Northern Arabia

The early to middle Holocene Humid Period led to a greening of today's arid Saharo-Arabian desert belt. While this phase is well defined in North Africa and the Southern Arabian Peninsula, robust evidence from Northern Arabia is lacking. Here we fill this gap with unprecedented annually to sub-decadally resolved proxy data from Tayma, the only known varved lake sediments in Northern Arabia. Based on stable isotopes, micro-facies analyses and varve and radiocarbon dating, we distinguish five phases of lake development and show that the wet phase in Northern Arabia from 8800-7900 years BP is considerably shorter than the commonly defined Holocene Humid Period (similar to 11,000-5500 years BP). Moreover, we find a two century-long peak humidity at times when a centennial-scale dry anomaly around 8200 years BP interrupted the Holocene Humid Period in adjacent regions. The short humid phase possibly favoured Neolithic migrations into Northern Arabia representing a strong human response to environmental changes

Olanzapine‐associated dose‐dependent alterations for weight and metabolic parameters in a prospective cohort

Metabolic abnormalities have been associated with olanzapine treatment. We assessed if olanzapine has dose-dependent effects on metabolic parameters with changes for weight, blood pressure, lipid and glucose profiles being modelled using linear mixed-effects models. The risk of metabolic abnormalities including early weight gain (EWG) (≥5% during first month) was assessed using mixed-effects logistic regression models. In 392 olanzapine-treated patients (median age 38.0 years, interquartile range [IQR] = 26.0-53.3, median dose 10.0 mg/day, IQR = 5.0-10.0 for a median follow-up duration of 40.0 days, IQR = 20.7-112.2), weight gain was not associated with olanzapine dose (p = 0.61) although it was larger for doses versus ≤10 mg/day (2.54 ± 5.55 vs. 1.61 ± 4.51% respectively, p = 0.01). Treatment duration and co-prescription of >2 antipsychotics, antidepressants, benzodiazepines and/or antihypertensive agents were associated with larger weight gain (p 10 mg/day were at higher EWG risk (odds risk: 2.15, 1.57-2.97). EWG might be prominent in high-dose olanzapine-treated patients with treatment duration and co-prescription of other medications being weight gain moderators. The lack of major dose-dependent patterns for weight gain emphasizes that olanzapine-treated patients are at weight gain risk regardless of the dose

Insight into the Last Glacial Maximum climate and environments of the Baikal region

This study presents a multi-proxy record from Lake Kotokel in the Baikal region at decadal-to-multidecadal resolution and provides a reconstruction of terrestrial and aquatic environments in the area during a 2000-year interval of globally harsh climate often referred to as the Last Glacial Maximum (LGM). The studied lake is situated near the eastern shoreline of Lake Baikal, in a climatically sensitive zone that hosts boreal taiga and cold deciduous forests, coldsteppe associationstypical for northern Mongolia, and mountain tundravegetation.The results provide a detailed picture of the period in focus, indicating (i) a driest phase (c. 24.0–23.4 cal. ka BP) with low precipitation, high summer evaporation, and low lake levels, (ii) a transitional interval of unstable conditions (c. 23.4–22.6 cal. ka BP), and (iii) a phase ( c. 22.6–22.0 cal. ka BP) of relatively high precipitation (and moisture availability) and relatively high lake levels. One hotly debated issue in late Quaternary research is regional summer thermal conditions during the LGM. Our chironomid-based reconstruction suggests at least 3.5 °C higher than present summer temperatures between c. 22.6 and 22.0 cal. ka BP, which are well in line with warmer and wetter conditions in the North Atlantic region inferred from Greenland ice-cores. Overall, it appears that environments in central Eurasia during the LGM were affected by much colder than present winter temperatures and higher than present summer temperatures, although the effects of temperature oscillations were strongly influenced by changes in humidity

Pirfenidone in idiopathic pulmonary fibrosis:expert panel discussion on the management of drug-related adverse events

Pirfenidone is currently the only approved therapy for idiopathic pulmonary fibrosis, following studies demonstrating that treatment reduces the decline in lung function and improves progression-free survival. Although generally well tolerated, a minority of patients discontinue therapy due to gastrointestinal and skin-related adverse events (AEs). This review summarizes recommendations based on existing guidelines, research evidence, and consensus opinions of expert authors, with the aim of providing practicing physicians with the specific clinical information needed to educate the patient and better manage pirfenidone-related AEs with continued pirfenidone treatment. The main recommendations to help prevent and/or mitigate gastrointestinal and skin-related AEs include taking pirfenidone during (or after) a meal, avoiding sun exposure, wearing protective clothing, and applying a broad-spectrum sunscreen with high ultraviolet (UV) A and UVB protection. These measures can help optimize AE management, which is key to maintaining patients on an optimal treatment dose.Correction in: Advances in Therapy, Volume 31, Issue 5, pp 575-576 , doi: 10.1007/s12325-014-0118-8</p

Dynamic Localization in Anisotropic Coulomb Systems: Field Induced Crossover of the Exciton Dimension

The effective dimensionality of excitons can be drastically changed by applying an alternating electric field. On the basis of a full three-dimensional description of both coherent and incoherent phenomena in anisotropic structures it is found that appropriate applied oscillating fields change the exciton wave function from anisotropic three dimensional to basically two dimensional. This effective-dimension change is caused by dynamic localization which leads to an increase of the exciton binding energy and of the corresponding oscillator strength