Showing 20 articles starting at article 81

< Previous 20 articles        Next 20 articles >

Categories: Paleontology: Climate, Physics: Acoustics and Ultrasound

Return to the site home page

     (via sciencedaily.com)     Original source 

A new study provides the first evidence that the Arctic's frozen soil is the dominant force shaping Earth's northernmost rivers, confining them to smaller areas and shallower valleys than rivers to the south. But as climate change weakens Arctic permafrost, the researchers calculate that every 1 degree Celsius of global warming could release as much carbon as 35 million cars emit in a year as polar waterways expand and churn up the thawing soil.

     (via sciencedaily.com)     Original source 

Researchers demonstrated a 300 GHz-band wireless link that was able to transmit data over a single channel at a rate of 240 gigabits per second. The wireless communication system employs signal generators based on lasers that have ultra-low phase noise in the sub-terahertz band. This rate is the highest so far reported at these frequencies and is a substantial step forward in 300 GHz-band communications for 6G networks.

     (via sciencedaily.com)     Original source 

Researchers are developing a new type of sensor that reacts to certain sound waves, causing it to vibrate. The sensor is a metamaterial that acquires its special properties through the structuring of the material. Passive sound-sensitive sensors could be used to monitor buildings, earthquakes or certain medical devices and save millions of batteries.

     (via sciencedaily.com)     Original source 

Instead of tubular commercial aircraft, other designs could be used in the future: Jets with a blended wing body would fly more efficiently and make less noise -- but how would the noise emissions from these new types of aircraft affect people?

     (via sciencedaily.com)     Original source 

The brown bear is one of the largest living terrestrial carnivores, and is widely distributed across the Northern Hemisphere. Unlike many other large carnivores that went extinct at the end of the last Ice Age (cave bear, sabretoothed cats, cave hyena), the brown bear is one of the lucky survivors that made it through to the present. The question has puzzled biologists for close to a century -- how was this so?

     (via sciencedaily.com)     Original source 

A new method predicts how much flooding a coastal community is likely to experience as hurricanes evolve due to climate change. Using New York as a test case, the model predicts Hurricane Sandy-level flooding will occur roughly every 30 years by 2099.

     (via sciencedaily.com)     Original source 

Owls produce negligible noise while flying. While many studies have linked the micro-fringes in owl wings to their silent flight, the exact mechanisms have been unclear. Now, a team of researchers has uncovered the effects of these micro-fringes on the sound and aerodynamic performance of owl wings through computational fluid dynamic simulations. Their findings can inspire biomimetic designs for the development of low-noise fluid machinery.

     (via sciencedaily.com)     Original source 

Scientists have revealed that low-frequency ultrasound influences blood parameters. The findings suggest that ultrasound's effect on haemoglobin can improve oxygen's transfer from the lungs to bodily tissues. The research was undertaken on 300 blood samples collected from 42 pulmonary patients.

     (via sciencedaily.com)     Original source 

A new way to measure the ocean oxygen level and its connections with carbon dioxide in the Earth's atmosphere during the last ice age could help explain the role oceans played in past glacial melting cycles and improve predictions of how ocean carbon cycles will respond to global warming.

     (via sciencedaily.com)     Original source 

A team of scientists has succeeded in cooling traveling sound waves in wave-guides considerably further than has previously been possible using laser light. This achievement represents a significant move towards the ultimate goal of reaching the quantum ground state of sound in wave-guides. Unwanted noise generated by the acoustic waves at room temperature can be eliminated. This experimental approach both provides a deeper understanding of the transition from classical to quantum phenomena of sound and is relevant to quantum communication systems and future quantum technologies.

     (via sciencedaily.com)     Original source 

The new theoretical research proposes that animal size over time depends on two key ecological factors.

     (via sciencedaily.com)     Original source 

Southern Africa contains the vast majority of the world's remaining populations of both black and white rhinoceroses (80% and 92%, respectively). The region's climate is changing rapidly as a result global warming. Traditional conservation efforts aimed at protecting rhinos have focused on poaching, but until now, there has been no analysis of the impact that climate change may have on the animals. A research team has recently reported that, though the area will be affected by both higher temperatures and changing precipitation, the rhinos are more sensitive to rising temperatures, which will quickly increase above the animals' acceptable maximum threshold.

     (via sciencedaily.com)     Original source 

Researchers have achieved a successful contrast agent-free imaging of complex structure of kidney vessels.

     (via sciencedaily.com)     Original source 

When combined with data from tree-ring records, stalagmites can open up a unique archive to study natural climate fluctuations, a research team has demonstrated. The researchers analyzed the isotopic composition of oxygen in a stalagmite formed from calcareous water in a cave in southern Germany. In conjunction with the data acquired from tree rings, they were able to reconstruct short-term climate fluctuations over centuries and correlate them with historically documented environmental events.

     (via sciencedaily.com)     Original source 

New research has precisely dated some of the oldest fossils of complex multicellular life in the world, helping to track a pivotal moment in the history of Earth when the seas began teeming with new lifeforms -- after four billion years of containing only single-celled microbes.

     (via sciencedaily.com)     Original source 

Human activity, from burning fossil fuels and fireplaces to the contaminated dust produced by mining, alters Earth's atmosphere in countless ways. Records of these impacts over time are preserved in everlasting polar ice that serves as a sort of time capsule, allowing scientists and historians to link Earth's history with that of human societies. In a new study, ice cores from Antartica show that lead and other toxic heavy metals linked to mining activities polluted the Southern Hemisphere as early as the 13th century.

     (via sciencedaily.com)     Original source 

The world is filled with a myriad of sounds and vibrations -- the gentle tones of a piano drifting down the hall, the relaxing purr of a cat laying on your chest, the annoying hum of the office lights. Imagine being able to selectively tune out noises of a certain frequency. Researchers have now synthesized polymer networks with two distinct architectures and crosslink points capable of dynamically exchanging polymer strands to understand how the network connectivity and bond exchange mechanisms govern the overall damping behavior of the network. The incorporation of dynamic bonds into the polymer network demonstrates excellent damping of sound and vibrations at well-defined frequencies.

     (via sciencedaily.com)     Original source 

A new study shows how state-of-the-art methods and perspectives from archaeology, history, and palaeoecology are shedding new light on 5,500 years of urban life.

     (via sciencedaily.com)     Original source 

Early in the 1970s, paleontologists discovered strange fossilized fruits between hardened rock from one of the largest volcanic eruptions in Earth's history. The identity of these fossils remained elusive for the next several decades. Using CT scanning, scientists have now determined they are the oldest fossils from species in the Frankincense and Myrrh family.

     (via sciencedaily.com)     Original source 

Simulations integrate historical records, fossils, and ancient DNA to reveal why the European bison nearly went extinct, and pinpoint optimal areas for conservation.   Since the near-extinction of the European bison, enormous conservation efforts have helped to restore wild populations, and its numbers are on the rise. However, the study authors argue that ensuring the species's long-term protection and recovery requires understanding why they nearly went extinct in the first place.    'Our study also suggests areas where rewilding attempts are most likely to be successful,' said lead author July Pilowsky, currently a disease ecologist at Cary Institute of Ecosystem Studies. Pilowsky completed the research while working on their PhD at University of Adelaide and University of Copenhagen.