The hot deformation behavior of an IN718 superalloy was studied by isothermal compression tests under the deformation temperature range of 950–1100°C and strain rate range of 0.001–1s−1 up to true ...strains of 0.05, 0.2, 0.4 and 0.7. Electron backscattered diffraction (EBSD) technique was employed to investigate systematically the effects of strain, strain rate and deformation temperature on the subgrain structures, local and cumulative misorientations and twinning phenomena. The results showed that the occurrence of dynamic recrystallization (DRX) is promoted by increasing strain and deformation temperature and decreasing strain rate. The microstructural changes showed that discontinuous dynamic recrystallization (DDRX), characterized by grain boundary bulging, is the dominant nucleation mechanism in the early stages of deformation in which DRX nucleation occurs by twining behind the bulged areas. Twin boundaries of nuclei lost their ∑3 character with further deformation. However, many simple and multiple twins can be also regenerated during the growth of grains. The results showed that continuous dynamic recrystallization (CDRX) is promoted at higher strains and large strain rates, and lower temperatures, indicating that under certain conditions both DDRX and CDRX can occur simultaneously during the hot deformation of IN718.
ABSTRACT
We present a sample of 74 gamma-ray bursts (GRBs) from the Fermi-GBM catalogue for which we compute the distance moduli and use them to constrain effective dark energy models. To overcome ...the circularity problem affecting GRBs as distance indicators, we calibrate the Amati relation of our sample with a cosmology-independent technique. Specifically, we use the latest observational Hubble parameter data, including associated systematics, to approximate the cosmic expansion through a Bezier parametric curve. We subsequently obtain the distance moduli of the GRBs and include the data in a suite of recent cosmological observations of the expansion history (Planck Compressed 2018, 2012 BOSS release of BAO data, and Pantheon SN Ia), to compute Bayesian posterior constraints for the standard cosmological model Lambda cold dark matter (ΛCDM), as well as ωCDM, and the CPL parametrization. Throughout the analysis, we strive to keep under control the error propagation and limit our GRB sample to avoid observational bias. As a result, we find no evidence in favour of the alternatives to ΛCDM model. The latter agrees very well with our calibrated sample of GRBs and presently available luminosity distance probes.
Why do fathers matter? Recent conceptual and theoretical advances regarding father–child relationships have demonstrated that fathers affect children's outcomes both directly and indirectly. To ...attain a complete developmental account of the ecologically rich contexts of child development, in this article, we recommend best practices regarding the conceptualization and assessment of father–child relationships that reflect contemporary family life. We also discuss conceptual and measurement issues pertaining to father–child relationships in different family configurations, including those with resident and nonresident fathers. We conclude with recommendations that can help developmental researchers advance our understanding of fathering, parenting, and children's development.
Environmental enrichment (EE) can improve the welfare of captive fish. Its objective is to provide new sensorial and motor stimulation in order to help meet their behavioural, physiological, ...morphological and psychological needs, whilst reducing stress and frequency of abnormal behaviours. In fish farms, rearing environments are usually designed from a human perspective and based on economic requirements, mainly for practical reasons for the farmer, with little consideration for animal welfare. Throughout aquaculture production cycles, many farming operations can be stressful for fish, and EE may not only help them cope with these stressful events but also improve their overall welfare. In recent years, increasing interest on the effects of EE in captive fish has focussed mainly on structural enrichment. However, there are many other enrichment strategies that merit attention (e.g. sensorial, occupational, social and dietary enrichment) and which may be of interest for fish farming. Here, we review in depth the existing literature on EE and its effects on the welfare of a wide range of farmed fish species, discussing the feasibility and potential applications of different EE strategies to promote fish welfare at a commercial scale. We also present a practical framework to address the design, validation and implementation of EE by the aquaculture industry, taking in consideration the technical challenges of providing enrichment for farmed fish.
This paper reports a room temperature visible light photocatalyzed method for the C–H amination of arenes and heteroarenes. A key enabling advance in this work is the design of N-acyloxyphthalimides ...as precursors to nitrogen-based radical intermediates for these transformations. A broad substrate scope is presented, including the selective meta-amination of pyridine derivatives. A radical aromatic substitution mechanism is proposed.
Hot deformation behavior of a medium carbon microalloyed steel Mirzadeh, H.; Cabrera, J.M.; Prado, J.M. ...
Materials science & engineering. A, Structural materials : properties, microstructure and processing,
04/2011, Letnik:
528, Številka:
10
Journal Article
Recenzirano
► Hot compression test under a wide range of temperature and strain rate. ► A step-by-step procedure for data analysis in hot deformation. ► Critical discussion on the application of constitutive ...equations.
The hot deformation behavior of a medium carbon microalloyed steel was studied using the hot compression flow curves corresponding to the temperature range of 850–1150
°C under strain rates from 0.0001 to 3
s
−1. A step-by-step procedure for data analysis in hot deformation was also given. The work hardening rate versus stress curves were used to reveal if dynamic recrystallization (DRX) occurred. The application of constitutive equations to determine the hot working constants of this material was critically discussed. Furthermore, the effect of Zener–Hollomon parameter (
Z) on the characteristic points of flow curves was studied using the power law relation. The deformation activation energy of this steel was determined as 394
kJ/mol and the normalized critical stress and strain for initiation of DRX were found to be 0.89 and 0.62, respectively. Some behaviors were also compared to other steels.
To characterize the neuropathologic features of neuromyelitis optica (NMO) at the medullary floor of the fourth ventricle and area postrema. Aquaporin-4 (AQP4) autoimmunity targets this region, ...resulting in intractable nausea associated with vomiting or hiccups in NMO.
This neuropathologic study was performed on archival brainstem tissue from 15 patients with NMO, 5 patients with multiple sclerosis (MS), and 8 neurologically normal subjects. Logistic regression was used to evaluate whether the presence of lesions at this level increased the odds of a patient with NMO having an episode of nausea/vomiting.
Six patients with NMO (40%), but no patients with MS or normal controls, exhibited unilateral or bilateral lesions involving the area postrema and the medullary floor of the fourth ventricle. These lesions were characterized by tissue rarefaction, blood vessel thickening, no obvious neuronal or axonal pathology, and preservation of myelin in the subependymal medullary tegmentum. AQP4 immunoreactivity was lost or markedly reduced in all 6 cases, with moderate to marked perivascular and parenchymal lymphocytic inflammatory infiltrates, prominent microglial activation, and in 3 cases, eosinophils. Complement deposition in astrocytes, macrophages, and/or perivascularly, and a prominent astroglial reaction were also present. The odds of nausea/vomiting being documented clinically was 16-fold greater in NMO cases with area postrema lesions (95% confidence interval 1.43-437, p = 0.02).
These neuropathologic findings suggest the area postrema may be a selective target of the disease process in NMO, and are compatible with clinical reports of nausea and vomiting preceding episodes of optic neuritis and transverse myelitis or being the heralding symptom of NMO.
Climate change is threatening crop productivity worldwide and new solutions to adapt crops to these environmental changes are urgently needed. Elevated temperatures driven by climate change affect ...developmental and physiological plant processes that, ultimately, impact on crop yield and quality. Plant roots are responsible for water and nutrients uptake, but changes in soil temperatures alters this process limiting crop growth. With the predicted variable climatic forecast, the development of an efficient root system better adapted to changing soil and environmental conditions is crucial for enhancing crop productivity. Root traits associated with improved adaptation to rising temperatures are increasingly being analyzed to obtain more suitable crop varieties. In this review, we will summarize the current knowledge about the effect of increasing temperatures on root growth and their impact on crop yield. First, we will describe the main alterations in root architecture that different crops undergo in response to warmer soils. Then, we will outline the main coordinated physiological and metabolic changes taking place in roots and aerial parts that modulate the global response of the plant to increased temperatures. We will discuss on some of the main regulatory mechanisms controlling root adaptation to warmer soils, including the activation of heat and oxidative pathways to prevent damage of root cells and disruption of root growth; the interplay between hormonal regulatory pathways and the global changes on gene expression and protein homeostasis. We will also consider that in the field, increasing temperatures are usually associated with other abiotic and biotic stresses such as drought, salinity, nutrient deficiencies, and pathogen infections. We will present recent advances on how the root system is able to integrate and respond to complex and different stimuli in order to adapt to an increasingly changing environment. Finally, we will discuss the new prospects and challenges in this field as well as the more promising pathways for future research.
•Words in the parafovea can be processed in parallel to fixated words.•Parafoveal words can be semantically processed and quickly integrated.•Parafoveal viewing of words can facilitate their ...subsequent semantic processing.•Parafovea-on-fovea effects interact with preview benefit effects.•FRPs with boundary paradigm is a suitable method to study parafoveal processing.
During reading parafoveal information can affect the processing of the word currently fixated (parafovea-on-fovea effect) and words perceived parafoveally can facilitate their subsequent processing when they are fixated on (preview effect). We investigated parafoveal processing by simultaneously recording eye movements and EEG measures. Participants read word pairs that could be semantically associated or not. Additionally, the boundary paradigm allowed us to carry out the same manipulation on parafoveal previews that were displayed until reader’s gaze moved to the target words. Event Related Potentials time-locked to the prime-preview presentation showed a parafoveal-on-foveal N400 effect. Fixation Related Potentials time locked to the saccade offset showed an N400 effect related to the prime-target relationship. Furthermore, this later effect interacted with the semantic manipulation of the previews, supporting a semantic preview benefit. These results demonstrate that at least under optimal conditions foveal and parafoveal information can be simultaneously processed and integrated.
ABSTRACT
We present a new X-Ray Accretion Disc-wind Emulator (xrade) based on the 2.5D Monte Carlo radiative transfer code that provides a physically motivated, self-consistent treatment of both ...absorption and emission from a disc wind by computing the local ionization state and velocity field within the flow. xrade is then implemented through a process that combines X-ray tracing with supervised machine learning. We develop a novel emulation method consisting in training, validating, and testing the simulated disc-wind spectra into a purposely built artificial neural network. The trained emulator can generate a single synthetic spectrum for a particular parameter set in a fraction of a second, in contrast to the few hours required by a standard Monte Carlo radiative transfer pipeline. The emulator does not suffer from interpolation issues with multidimensional spaces that are typically faced by traditional X-ray fitting packages such as xspec. xrade will be suitable to a wide number of sources across the black hole mass, ionizing luminosity, and accretion rate scales. As an example, we demonstrate the applicability of xrade to the physical interpretation of the X-ray spectra of the bright quasar PDS 456, which hosts the best-established accretion disc wind observed to date. We anticipate that our emulation method will be an indispensable tool for the development of high-resolution theoretical models, with the necessary flexibility to be optimized for the next generation microcalorimeters onboard future missions, like X-Ray Imaging and Spectroscopy Mission (XRISM)/Resolve and Athena/X-ray Integral Field Unit (X-IFU). This tool can also be implemented across a wide variety of X-ray spectral models and beyond.
PDF
