Complex Crater Collapse: A Comparison of the Block and Melosh Acoustic Fluidization Models of Transient Target Weakening.

The collapse of large impact craters requires a temporary reduction in the resistance to shear deformation of the target rocks. One explanation for such weakening is acoustic fluidization, where impact-generated pressure fluctuations temporarily and locally relieve overburden pressure facilitating slip. A model of acoustic fluidization widely used in numerical impact simulations is the Block model.

Paleomagnetic evidence for a long-lived, potentially reversing martian dynamo at ~3.9 Ga.

The 4.1-billion-year-old meteorite Allan Hills 84001 (ALH 84001) may preserve a magnetic record of the extinct martian dynamo. However, previous paleomagnetic studies have reported heterogeneous, nonunidirectional magnetization in the meteorite at submillimeter scales, calling into question whether it records a dynamo field.

Momentum transfer from the DART mission kinetic impact on asteroid Dimorphos.

The NASA Double Asteroid Redirection Test (DART) mission performed a kinetic impact on asteroid Dimorphos, the satellite of the binary asteroid (65803) Didymos, at 23:14 UTC on 26 September 2022 as a planetary defence test. DART was the first hypervelocity impact experiment on an asteroid at size and velocity scales relevant to planetary defence, intended to validate kinetic impact as a means of asteroid deflection. Here we report a determination of the momentum transferred to an asteroid by kinetic impact.

Carbon myopia: The urgent need for integrated social, economic and environmental action in the livestock sector.

Livestock have long been integral to food production systems, often not by choice but by need. While our knowledge of livestock greenhouse gas (GHG) emissions mitigation has evolved, the prevailing focus has been-somewhat myopically-on technology applications associated with mitigation. Here, we (1) examine the global distribution of livestock GHG emissions, (2) explore social, economic and environmental co-benefits and trade-offs associated with mitigation interventions and (3) critique approaches for quantifying GHG emissions.

Methane Emissions from Ruminants in Australia: Mitigation Potential and Applicability of Mitigation Strategies.

Anthropomorphic greenhouse gases are raising the temperature of the earth and threatening ecosystems. Since 1950 atmospheric carbon dioxide has increased 28%, while methane has increased 70%. Methane, over the first 20 years after release, has 80-times more warming potential as a greenhouse gas than carbon dioxide.

Precise radiometric age establishes Yarrabubba, Western Australia, as Earth's oldest recognised meteorite impact structure.

The ~70 km-diameter Yarrabubba impact structure in Western Australia is regarded as among Earth's oldest, but has hitherto lacked precise age constraints. Here we present U-Pb ages for impact-driven shock-recrystallised accessory minerals. Shock-recrystallised monazite yields a precise impact age of 2229 ± 5 Ma, coeval with shock-reset zircon.

Skin impedance reduction for electrophysiology measurements using ultrasonic skin permeation: initial report and comparison to current methods.

Ultrasonic skin permeation using the SonoPrep (Sontra Medical Corporation, Franklin, MA) device was evaluated as a methodto reduce skin impedance for electrophystology measurements. SonoPrep treatment was compared to QuikPrep (Quinton , Inc, Bothell, WA) and mechanical abrasion with the Kendall Excel electrode release liner (Tyco Healthcare, Mansfield, MA). Five skin sites for each prepping method were treated on the backs of 10 volunteer subjects.

Clinical evaluation of a continuous minimally invasive glucose flux sensor placed over ultrasonically permeated skin.

Frequent monitoring and tight metabolic control of blood glucose levels can reduce microvascular complications and subsequent co-morbidities in patients with diabetes. Self-monitoring with finger sticks provides intermittent data at best, and results in poor compliance. We report on a minimally invasive system that continually measures glucose flux through ultrasonically permeated skin.