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Latitudinal variations in δ30Si and δ15N signatures along the Peruvian shelf : Quantifying the effects of nutrient utilization versus denitrification over the past 600 years

The stable sedimentary nitrogen isotope compositions of bulk organic matter (δ15Nbulk) and the silicon isotope composition of diatoms (δ30SiBSi) both mainly reflect the degree of past nutrient utilization by primary producers. However, in ocean areas where anoxic and suboxic conditions prevail, the δ15Nbulk signal ultimately recorded within the sediments is also influenced by water column denitrif

Changes in diatom productivity and upwelling intensity off Peru since the Last Glacial Maximum : Response to basin-scale atmospheric and oceanic forcing

New records of stable silicon isotope signatures (δ30Si) together with concentrations of biogenic opal and organic carbon from the central (9°S) and northern (5°S) Peruvian margin reveal changes in diatom productivity and nutrient utilization during the past 20,000 years. The findings are based on a new approach using the difference between the δ30Si signatures of small (11–32 µm) and large (>150

Stable silicon isotope signatures of marine pore waters – Biogenic opal dissolution versus authigenic clay mineral formation

Dissolved silicon isotope compositions have been analysed for the first time in pore waters (δ30SiPW) of three short sediment cores from the Peruvian margin upwelling region with distinctly different biogenic opal content in order to investigate silicon isotope fractionation behaviour during early diagenetic turnover of biogenic opal in marine sediments. The δ30SiPW varies between +1.1‰ and +1.9‰

Factors controlling plankton community production, export flux, and particulate matter stoichiometry in the coastal upwelling system off Peru

Eastern boundary upwelling systems (EBUS) are among the most productive marine ecosystems on Earth. The production of organic material is fueled by upwelling of nutrient-rich deep waters and high incident light at the sea surface. However, biotic and abiotic factors can modify surface production and related biogeochemical processes. Determining these factors is important because EBUS are considere

Impact of ambient conditions on the Si isotope fractionation in marine pore fluids during early diagenesis

Benthic fluxes of dissolved silicon (Si) from sediments into the water column are driven by the dissolution of biogenic silica (bSiO2) and terrigenous Si minerals and modulated by the precipitation of authigenic Si phases. Each of these processes has a specific effect on the isotopic composition of silicon dissolved in sediment pore fluids, such that the determination of pore fluid 30Si values can

Sea surface and subsurface circulation dynamics off equatorial Peru during the last ∼17 kyr

The complex deglacial to Holocene oceanographic development in the Gulf of Guayaquil (Eastern Equatorial Pacific) is reconstructed for sea surface and subsurface ocean levels from (isotope) geochemical proxies based on marine sediment cores. At sea surface, southern sourced Cold Coastal Water and tropical Equatorial Surface Water/Tropical Surface Water are intimately related. In particular since ∼

The silicon isotope composition of Ethmodiscus rex laminated diatom mats from the tropical West Pacific : Implications for silicate cycling during the Last Glacial Maximum

The cause of massive blooms of Ethmodiscus rex laminated diatom mats (LDMs) in the eastern Philippine Sea (EPS) during the Last Glacial Maximum (LGM) remains uncertain. In order to better understand the mechanism of formation of E. rex LDMs from the perspective of dissolved silicon (DSi) utilization, we determined the silicon isotopic composition of single E. rex diatom frustules (δ30SiE. rex) fro

Dissolved silicon isotope dynamics in large river estuaries

Estuarine systems are of key importance for the riverine input of silicon (Si) to the ocean, which is a limiting factor of diatom productivity in coastal areas. This study presents a field dataset of surface dissolved Si isotopic compositions (δ30SiSi(OH)4) obtained in the estuaries of three of the world's largest rivers, the Amazon (ARE), Yangtze (YRE), and Pearl (PRE), which cover different clim

Comparisons on flow characteristics and film cooling performance of cylindrical and sister holes with/without internal coolant crossflow

Simulations and comparisons on the influence of internal coolant crossflow of a novel film cooling hole design, called “sister holes”, and a baseline cylindrical hole were performed with an established turbulence model. The results show that sister holes can provide better film cooling performance than the baseline case at three blowing ratios, and as the blowing ratio increases the sister holes s

Small-scale dosimetry for alpha particle 241Am source cell irradiation and estimation of γ-H2AX foci distribution in prostate cancer cell line PC3

Background: The development of new targeted alpha therapies motivates improving alpha particle dosimetry. For alpha particles, microscopic targets must be considered to estimate dosimetric quantities that can predict the biological response. As double-strand breaks (DSB) on DNA are the main cause of cell death by ionizing radiation, cell nuclei are relevant volumes necessary to consider as targets

Input in study abroad and views from acquisition : Focus on constructs, operationalization and measurement issues: Introduction to the special issue

This article briefly discusses the notion of input in a study abroad perspective, situating it against how input is treated in second language acquisition (SLA) more broadly, with a focus on methodological issues, operationalizations, and measurements. It further introduces three studies that examine input as studied in ‘the real wild’, and two studies that instead focus on ‘the digital wild’.

Experiences of patients with hip fractures after discharge from hospital

Background: To achieve successful rehabilitation after hip fracture and meet patient needs it is important to listen to how individual patients perceive their situation. Purpose: The aim of this study was to explore how patients with hip fractures experience the time after hospitalization. Methods: A qualitative study was performed, data were analyzed using content analysis and included a total of

Entrepreneurial Beliefs of Refugees : It’s Not Where They’re From, But Where They Go

This paper investigates whether structuralist and culturalist approaches to migrant entrepreneurship can explain the early-stage entrepreneurship of recently arrived refugees. Specifically, we empirically test three hypotheses on how refugees’ current geographical location and ethnic origin matter for their entrepreneurial beliefs, which provide the cognitive and affective foundations for entrepre

Transit timing variations of AU Microscopii b and c

Here we report large-amplitude transit timing variations (TTVs) for AU Microcopii b and c as detected in combined TESS (2018, 2020) and CHEOPS (2020, 2021) transit observations. AU Mic is a young planetary system with a debris disk and two transiting warm Neptunes. A TTV on the order of several minutes was previously reported for AU Mic b, which was suggested to be an outcome of mutual perturbatio

Extending depolarized DLS measurements to turbid samples

The application of dynamic light scattering to soft matter systems has strongly profited from advanced approaches such as the so-called modulated 3D cross correlation technique (Mod3D-DLS) that suppress contributions from multiple scattering, and can therefore be used for the characterization of turbid samples. Here we now extend the possibilities of this technique to allow for depolarized light s

Iterative importance sampling with Markov chain Monte Carlo sampling in robust Bayesian analysis

Bayesian inference under a set of priors, called robust Bayesian analysis, allows for estimation of parameters within a model and quantification of epistemic uncertainty in quantities of interest by bounded (or imprecise) probability. Iterative importance sampling can be used to estimate bounds on the quantity of interest by optimizing over the set of priors. A method for iterative importance samp

The atmosphere and architecture of WASP-189 b probed by its CHEOPS phase curve

Context. Gas giants orbiting close to hot and massive early-type stars can reach dayside temperatures that are comparable to those of the coldest stars. These aultra-hot Jupitersahave atmospheres made of ions and atomic species from molecular dissociation and feature strong day-to-night temperature gradients. Photometric observations at different orbital phases provide insights on the planetas atm

Sequence of flexion contracture development in the lower limb : a longitudinal analysis of 1,071 children with cerebral palsy

Background: To prevent severe contractures and their impact on adjacent joints in children with cerebral palsy (CP), it is crucial to treat the reduced range of motion early and to understand the order by which contractures appear. The aim of this study was to determine how a hip–knee or ankle contracture are associated with the time to and sequence of contracture development in adjacent joints. M

Heart age estimated using explainable advanced electrocardiography

Electrocardiographic (ECG) Heart Age conveying cardiovascular risk has been estimated by both Bayesian and artificial intelligence approaches. We hypothesised that explainable measures from the 10-s 12-lead ECG could successfully predict Bayesian 5-min ECG Heart Age. Advanced analysis was performed on ECGs from healthy subjects and patients with cardiovascular risk or proven heart disease. Regress

Shorter reproductive life span is associated with increased cardiovascular risk and total mortality in Swedish women from an observational, population-based study

Objectives: Reproductive history of women is of importance to estimate cardiovascular disease (CVD) risk. One aspect of that history is the reproductive life span (RLS), the period between onset of menarche and menopause. Previous studies have indicated an increased risk associated with shorter RLS, but this has never previously been tested in Scandinavian women. Our aim was to investigate such as