The development of intensive care medicine started over more than 50 years. Effective organ system support for ventilation initially and subsequently for circulation, nutrition and renal function ...resulted in improved outcomes in patients with a variety of severe medical conditions. One of the unfortunate consequences of this development was that it did not allow dying or prolonged the dying process and without the possibility of recovery to a quality of life acceptable to the patients. The early realization of this dilemma ultimately led to broad ethical discussions concerning withholding and withdrawal of curative therapies in intensive care units, and introducing palliative care.
The Paleogene succession of the Helmstedt Lignite Mining District in Northern Germany includes coastal peat mire records from the latest Paleocene to the middle Eocene at the southern edge of the ...Proto-North Sea. Therefore, it covers the different long- and short-term climate perturbations of the Paleogene greenhouse. 56 samples from three individual sections of a lower Eocene seam in the record capture the typical succession of the vegetation in a coastal wetland during a period that was not affected by climate perturbation. This allows facies-dependent vegetational changes to be distinguished from those that were climate induced. Cluster analyses and NMDS of well-preserved palynomorph assemblages reveal four successional stages in the vegetation during peat accumulation: (1) a coastal vegetation, (2) an initial mire, (3) a transitional mire, and (4) a terminal mire. Biodiversity measures show that plant diversity decreased significantly in the successive stages. The highly diverse vegetation at the coast and in the adjacent initial mire was replaced by low diversity communities adapted to wet acidic environments and nutrient deficiency. The palynomorph assemblages are dominated by elements such as Alnus (Betulaceae) or Sphagnum (Sphagnaceae). Typical tropical elements which are characteristic for the middle Eocene part of the succession are missing. This indicates that a more warm-temperate climate prevailed in northwestern Germany during the early lower Eocene.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Submarine mega‐slides involving hundreds of cubic kilometers of slope material pose a major threat due to their potential to destroy offshore infrastructure and trigger devastating tsunamis. The ...Sahara Slide Complex affected about 50,000 km2 of the northwestern (NW) African continental margin. Previous studies focused either on its distal depositional zone or the uppermost headwall area, but failed in reconstructing the succession of individual slide events within the entire headwall area. New hydroacoustic data reveal a complex slide morphology including three main acoustic facies, large scale slide blocks, linear troughs, multiple glide planes and three major headwall scarps (the upper, southern and lower headwall). The evacuated slide scar hosts chaotic slide deposits that cover stratified sediments in the upper and southern headwall area, but are vertically stacked onto older slide deposits in the lower headwall area. Based on these observations, and dating of recently collected sediment samples, we reconstructed the history of slope failures that led to the formation of the structurally and morphologically complex headwall area of the Sahara Slide. Slope instability initiated when the lower headwall failed at ∼60 kyr, followed by the failure of the northeastern upper headwall at ∼14 kyr. Around 6 kyr, a major slide within the upper headwall area took place, followed by a series of smaller events within the southern and most‐proximal upper headwall area. The youngest of these slides occurred around 2 kyr. This scenario suggests a long‐lasting history of successive slope failures for the Sahara Slide Complex along the NW African continental slope.
Plain Language Summary
Giant submarine landslides are a natural hazard, which can threaten marine infrastructure including seafloor communication cables, and potentially generate dangerous tsunami. The Sahara Slide Complex is a submarine landslide that affected an area of about 50,000 km2 offshore the coast of northwestern Africa. It is important to know the mechanisms and the geological framework of the Sahara Slide Complex to better understand the risk of such large landslides to coastal populations and infrastructure. Therefore, we collected data for imaging the seafloor, understanding the structure below the seafloor and reconstructing ages of individual slide bodies. Three areas with submarine landslides were found in the headwall area of the Sahara Slide Complex. We observed landslide material and lined troughs on the seafloor. Our data show a long history of unstable slopes in the Sahara slide Complex area: it began around 60,000 years BP at the lower headwall, followed by the northeastern part of the upper headwall area at 14,000 years BP. The main slide of the upper headwall area occurred at 6,000 years BP. Slides in the southern headwall area and shallowest part of the upper headwall area appeared with the youngest slide at 2,000 years BP.
Key Points
Detailed structural and morphological analysis of the headwall area of the giant Sahara Slide Complex
The headwall area was shaped by a series of individual slope failures over the last 60 kyr
Failure occurs along multiple stratigraphic layers throughout the slope sediments
Periodically patterned metamaterials are known for exhibiting wave properties similar to the ones observed in electronic band structures in crystal lattices. In particular, periodic ferromagnetic ...materials are characterized by the presence of bands and band gaps in their spin-wave spectrum at tunable GHz frequencies. Recently, the fabrication of magnets hosting Dzyaloshinskii-Moriya interactions has been pursued with high interest since properties, such as the stabilization of chiral spin textures and nonreciprocal spin-wave propagation, emerge from this antisymmetric exchange coupling. In this context, to further engineer the magnon band structure, we propose the implementation of magnonic crystals with periodic Dzyaloshinskii-Moriya interactions, which can be obtained, for instance, via patterning of periodic arrays of heavy metal wires on top of an ultrathin magnetic film. We demonstrate through theoretical calculations and micromagnetic simulations that such systems show an unusual evolution of the standing spin waves around the gaps. We also predict the emergence of indirect gaps and flat bands, effects that depend on the strength of the Dzyaloshinskii-Moriya interaction. Such phenomena, which have been previously observed in different systems, are observed here simultaneously, opening new routes towards engineered metamaterials for spin-wave-based devices.
A theoretical approach has been developed to study the spin-wave dynamics of magnetization-graded ferromagnetic films, where the magnetic properties change along the film thickness. The theory is ...based on a multilayer approach, where the influence of both long-range dipolar interactions and interlayer exchange coupling between sublayers is included. This allows for instance to describe films with a continuous variation of the saturation magnetization along the thickness. A systematic study is carried out in order to analyze different profiles of the saturation magnetization, which is checked through a test of convergence. It is found that the spin-wave dispersion is significantly modified when the strength of the magnetization changes in the bulk film, where a notable frequency non-reciprocity of two counter propagating spin waves is predicted. This is associated with heterosymmetric mode profiles and a modification of the conventional quantization condition associated to perpendicular standing spin-wave modes. Micromagnetic simulations have been carried out to validate the model, where a perfect agreement is reached between both methods. These results show that magnetization-graded ferromagnetic films can be used to channel and control spin waves, thus promoting different kinds of functionalities for magnon-based devices.
Abstract
Spin pumping from a metallic ferromagnet (FM) into an insulating antiferromagnet has been studied across the magnetic phase transition by means of temperature-dependent, broad-band ...ferromagnetic resonance (FMR) experiments. A set of spin pumping heterostructures consisting of Permalloy (Ni
80
Fe
20
) as FM and Zn
1
−
x
Co
x
O with
x
=
0.3
,
0.5
and 0.6 (Co:ZnO) as partially compensated antiferromagnetic insulator has been used for which previous experiments have already pointed out the possibility of the existence of spin-pumping. The present experiments allow to reliably separate the various contributions of the temperature-dependent Gilbert damping parameter to the FMR line-width. A careful analysis of the obtained data demonstrates a significant increase of the temperature-dependence of the Gilbert damping parameter
α
(
T
)
around the magnetic phase transition of Co:ZnO which extends up to room temperature, confirming spin pumping into the fluctuating spin sink of an antiferromagnetic/paramagnetic insulator.
•Female brains are highly dynamic, remodelling throughout the normal ovarian cycle.•They also demonstrate unique changes across various life stages.•Females uniquely respond to early life challenges, ...pregnancy, disease and old-age.•The female brain is under-researched but the field is, encouragingly, growing.
The female brain is highly dynamic and can fundamentally remodel throughout the normal ovarian cycle as well as in critical life stages including perinatal development, pregnancy and old-age. As such, females are particularly vulnerable to infections, psychological disorders, certain cancers, and cognitive impairments. We will present the latest evidence on the female brain; how it develops through the neonatal period; how it changes through the ovarian cycle in normal individuals; how it adapts to pregnancy and postpartum; how it responds to illness and disease, particularly cancer; and, finally, how it is shaped by old age. Throughout, we will highlight female vulnerability to and resilience against disease and dysfunction in the face of environmental challenges.
Given the financial demands of attending college, the transition to new living situations, abrupt changes in social support, and overall lifestyle adjustments, college students are at an increased ...risk of food insecurity (FI) compared to the general population. Collegiate athletes experience an even greater risk of FI as a result of greater time commitments and energy demands associated with their sports. This heightened vulnerability poses a tremendous threat to student-athletes' academic and athletic achievements. This study aims to address the prevalence and primary determinants of FI among collegiate athletes while providing potential solutions to navigate and alleviate the effects of diminished food security among this demographic. To address these aims, a total of 18 articles were selected from both peer-reviewed and gray literature. The U.S. Household Food Security Survey Module (US-HFSSM) survey tools were predominantly utilized across universities throughout the United States to gather data on FI. Student-athletes reported experiencing FI across various regions of the United States, including universities in the northeastern states
= 5), the southwest region (
= 3), the southeast region (
= 3), the northwest (
= 1), and the Midwest (
= 1). Overall, FI prevalence rates ranged from 9.9% to 65%, and the most significant contributors included limited financial resources, time management, meal plans, and housing location/amenities. These findings highlight a need for screening, education, and interventions to address FI among collegiate athletes.
Multiple prebiotic metals mediate translation Bray, Marcus S.; Lenz, Timothy K.; Haynes, Jay William ...
Proceedings of the National Academy of Sciences - PNAS,
11/2018, Letnik:
115, Številka:
48
Journal Article
Recenzirano
Odprti dostop
Today, Mg2+ is an essential cofactor with diverse structural and functional roles in life’s oldest macromolecular machine, the translation system. We tested whether ancient Earth conditions (low O₂, ...high Fe2+, and high Mn2+) can revert the ribosome to a functional ancestral state. First, SHAPE (selective 2′-hydroxyl acylation analyzed by primer extension) was used to compare the effect of Mg2+, Fe2+, and Mn2+ on the tertiary structure of rRNA. Then, we used in vitro translation reactions to test whether Fe2+ or Mn2+ could mediate protein production, and quantified ribosomal metal content. We found that (i) Mg2+, Fe2+, and Mn2+ had strikingly similar effects on rRNA folding; (ii) Fe2+ and Mn2+ can replace Mg2+ as the dominant divalent cation during translation of mRNA to functional protein; and (iii) Fe and Mn associate extensively with the ribosome. Given that the translation system originated and matured when Fe2+ and Mn2+ were abundant, these findings suggest that Fe2+ and Mn2+ played a role in early ribosomal evolution.
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