9 research outputs found
Earth-Like: An education & outreach tool for exploring the diversity of planets like our own
Earth-Like is an interactive website and twitter bot that allows users to
explore changes in the average global surface temperature of an Earth-like
planet due to variations in the surface oceans and emerged land coverage, rate
of volcanism (degassing), and the level of the received solar radiation. The
temperature is calculated using a simple carbon-silicate cycle model to change
the level of in the atmosphere based on the chosen parameters. The
model can achieve a temperature range exceeding C to C
by varying all three parameters, including freeze-thaw cycles for a planet with
our present-day volcanism rate and emerged land fraction situated at the outer
edge of the habitable zone. To increase engagement, the planet is visualised by
using a neural network to render an animated globe, based on the calculated
average surface temperature and chosen values for land fraction and volcanism.
The website and bot can be found at earthlike.world and on twitter as
@earthlikeworld. Initial feedback via a user survey suggested that Earth-Like
is effective at demonstrating that minor changes in planetary properties can
strongly impact the surface environment. The goal of the project is to increase
understanding of the challenges we face in finding another habitable planet due
to the likely diversity of conditions on rocky worlds within our Galaxy.Comment: Accepted for publication in the International Journal of Astrobiology
(IJA
Antiviral Activity and Molecular Geometry of Some New Symmetrical Tris(aminoalkyl)amine Derivatives
Early origin of sweet perception in the songbird radiation
From savory to sweet
Seeing a bird eat nectar from a flower is a common sight in our world. The ability to detect sugars, however, is not ancestral in the bird lineage, where most species were carnivorous. Toda
et al.
looked at receptors within the largest group of birds, the passerines or songbirds, and found that the emergence of sweet detection involved a single shift in a receptor for umami (see the Perspective by Barker). This ancient change facilitated sugar detection not just in nectar feeding birds, but also across the songbird group, and in a way that was different from, though convergent with, that in hummingbirds.
Science
, abf6505, this issue p.
226
; see also abj6746, p.
154
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Asteroid (101955) Bennu in the laboratory: Properties of the sample collected by OSIRIS ‐ REx
On September 24, 2023, NASA's OSIRIS‐REx mission dropped a capsule to Earth containing ~120 g of pristine carbonaceous regolith from Bennu. We describe the delivery and initial allocation of this asteroid sample and introduce its bulk physical, chemical, and mineralogical properties from early analyses. The regolith is very dark overall, with higher‐reflectance inclusions and particles interspersed. Particle sizes range from submicron dust to a stone ~3.5 cm long. Millimeter‐scale and larger stones typically have hummocky or angular morphologies. Some stones appear mottled by brighter material that occurs as veins and crusts. Hummocky stones have the lowest densities and mottled stones have the highest. Remote sensing of Bennu's surface detected hydrated phyllosilicates, magnetite, organic compounds, carbonates, and scarce anhydrous silicates, all of which the sample confirms. We also find sulfides, presolar grains, and, less expectedly, Mg,Na‐rich phosphates, as well as other trace phases. The sample's composition and mineralogy indicate substantial aqueous alteration and resemble those of Ryugu and the most chemically primitive, low‐petrologic‐type carbonaceous chondrites. Nevertheless, we find distinct hydrogen, nitrogen, and oxygen isotopic compositions, and some of the material we analyzed is enriched in fluid‐mobile elements. Our findings underscore the value of sample return—especially for low‐density material that may not readily survive atmospheric entry—and lay the groundwork for more comprehensive analyses
Subsurface chlorophyll maximum in the tropical and subtropical western Pacific Ocean: Vertical profiles of phytoplankton biomass and its relationship with chlorophylla and particulate organic carbon
A dormant microbial component in the development of pre-eclampsia
Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of “preeclampsia” that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one