Tag Archives: princeton university

Tiny acts of microbe justice help reveal how nature fights freeloaders

By Guest PostJanuary 16, 2014Sciencebacteria vibrio cholerae, bioremediation, biosphere, bonnie bassler, carey nadell, fights freeloaders, history, howard stone, industrial cleanup, infection, knut drescher, life on earth, mechanism, microbe, nitrogen containing molecules, princeton university, public goods dilemma, recycle, tiny acts, treating a disease, v cholera

The idea of everyone in a community pitching in is so universal that even bacteria have a system to prevent the layabouts of their kind from enjoying the fruit of others’ hard work, Princeton University researchers have discovered.

Groups of the bacteria Vibrio cholerae deny loafers their unjust desserts by keeping the food generated by the community’s productive members away from V. cholerae that attempt to live on others’ leftover nutrients, the researchers report in the journal Current Biology. The researchers found that individual bacteria produce a thick coating around themselves to prevent nutrients from drifting over to the undeserving. Alternatively, the natural flow of fluids over the surface of bacterial communities can wash away excess food before the freeloaders can indulge. (more…)

Opposing phenomena possible key to high-efficiency electricity delivery

By Guest PostDecember 29, 2013Scienceali yazdani, andras gyenis, binghamton university, british columbia, coexistence, copper oxide, da silva neto, eduardo, electricity delivery, high efficiency, high temperature superconductors, hts, material, mystery in physics, pegor aynajian, phenomena, princeton university, rigid pattern, superconductivity, university, xray scattering technique

The coexistence of two opposing phenomena might be the secret to understanding the enduring mystery in physics of how materials heralded as the future of powering our homes and communities actually work, according to Princeton University-led research. Such insight could help spur the further development of high-efficiency electric-power delivery.

Published in the journal Science, the findings provide a substantial clue for unraveling the inner workings of high-temperature superconductors (HTS) based on compounds containing copper and oxygen, or copper oxides. Copper-oxide high-temperature superconductors are prized as a material for making power lines because of their ability to conduct electricity with no resistance. It’s been shown that the material can be used to deliver electrical power like ordinary transmission lines, but with no loss of energy. In addition, typical superconductors need extremely low temperatures of roughly -243 degrees Celsius (-405 degrees Fahrenheit) to exhibit this 100-percent efficiency. A copper oxide HTS, however, can reach this level of efficiency at a comparatively toasty -135 degrees Celsius (-211 degrees Fahrenheit), which is achievable using liquid nitrogen. (more…)

‘Tiger stripes’ underneath Antarctic glaciers slow the flow

By Guest PostNovember 30, 2013Environmentantarctic glaciers, antarctic ice, bed of rock, british antarctic survey, climate change, douglas macayeal, Europe, flow of glaciers, friction zones, massive antarctic glaciers, mathematical modeling, North America, olga sergienko, pattern, pine island glacier, princeton university, richard hindmarsh, satellite measurements, sea-level rise, sediment, thwaites glacier, tiger stripes, university of chicago, warming climate, west antarctica

Narrow stripes of dirt and rock beneath massive Antarctic glaciers create friction zones that slow the flow of ice toward the sea, researchers at Princeton University and the British Antarctic Survey have found. Understanding how these high-friction regions form and subside could help researchers understand how the flow of these glaciers responds to a warming climate.

Just as no-slip strips on flooring prevent people from slipping on a wet floor, these ribs or “tiger stripes” — named in reference to Princeton’s tiger mascot — provide friction that hinders the glaciers from slipping along the underlying bed of rock and sediment, the researchers report online in the journal Science. (more…)

Small bits of genetic material fight cancer’s spread

By Guest PostOctober 25, 2013Healthbone fracture, bone lesions, bone metastasis, brian ell, cancer, class of molecules, combat, david waning, disease, extreme pain, gene, genetic material, Germany, hamburg, indiana university, indianapolis, khalid mohammad, micrornas, nerve compression, pathological activity, predictors of metastasis, princeton university, therapeutic target, theresa guise, university cancer center, yibin kang

A class of molecules called microRNAs may offer cancer patients two ways to combat their disease.

Researchers at Princeton University have found that microRNAs — small bits of genetic material capable of repressing the expression of certain genes — may serve as both therapeutic targets and predictors of metastasis, or a cancer’s spread from its initial site to other parts of the body. The research was published in the journal Cancer Cell. (more…)

How red crabs on Christmas Island speak for the tropics

By Guest PostOctober 12, 2013Environment, Natureallison shaw, australia national university, christmas island, climate pattern, cocos, crabs larvae, earth, ecosystem, el niño, erratic rainfall, fluctuations in rainfall, forest dynamics, indian ocean, kathryn kelly, keeling islands, migration data, migratory animals, next generation, North America, ocean, princeton university, red crabs, tropical zones, tropics, university of minnesota, university of washington

Each year, the land-dwelling Christmas Island red crab takes an arduous and shockingly precise journey from its earthen burrow to the shores of the Indian Ocean where weeks of mating and egg laying await.

Native to the Australian territories of Christmas Island and the Cocos (Keeling) Islands, millions of the crabs start rolling across the island roads and landscape in crimson waves when the November rains begin. After a two-week scuttle to the sea, the male crab sets up and defends a mating burrow for himself and a female of his kind, the place where she will incubate their clutch for another two weeks. Before the morning of the high tide that precedes the December new moon, the females must emerge to release their millions of eggs into the ocean. A month later, the next generation of crabs comes ashore. (more…)

Tropical forest carbon absorption may hinge on an odd couple

By Guest PostOctober 7, 2013Environmentabsorb, atmosphere, carbo loading bacteria, carbon absorption, carbon dioxide, carbon sink, component of biodiversity, david medvigy, dylan craven, Europe, excess nitrogen, human activities, infectious bacteria, jefferson hall, journal nature, lars hedin, legume family, michiel van breugel, models, nitrogen, nitrogen fixation, nitrogen fixing trees, non legume trees, North America, photosynthesis, princeton university, rhizobia, root nodules, sarah batterman, stri, tropical forest, united states

A unique housing arrangement between a specific group of tree species and a carbo-loading bacteria may determine how well tropical forests can absorb carbon dioxide from the atmosphere, according to a Princeton University-based study. The findings suggest that the role of tropical forests in offsetting the atmospheric buildup of carbon from fossil fuels depends on tree diversity, particularly in forests recovering from exploitation.

Tropical forests thrive on natural nitrogen fertilizer pumped into the soil by trees in the legume family, a diverse group that includes beans and peas, the researchers report in the journal Nature. The researchers studied second-growth forests in Panama that had been used for agriculture five to 300 years ago. The presence of legume trees ensured rapid forest growth in the first 12 years of recovery and thus a substantial carbon “sink,” or carbon-storage capacity. Tracts of land that were pasture only 12 years before had already accumulated as much as 40 percent of the carbon found in fully mature forests. Legumes contributed more than half of the nitrogen needed to make that happen, the researchers reported. (more…)

Movement of marine life follows speed and direction of climate change

By Guest PostSeptember 15, 2013Environmentbering sea, biological data, british columbia, changes in temperature, climate change, climate data, climate velocity, daniel pauly, direction, geological features, gulf of alaska, jorge sarmiento, malin pinsky, marine life, movement, ocean temperature move, predictions, princeton university, Rutgers University, simon levin, speed, survey data, temperature change, united states, university, warmer oceans

Scientists expect climate change and warmer oceans to push the fish that people rely on for food and income into new territory. Predictions of where and when species will relocate, however, are based on broad expectations about how animals will move and have often not played out in nature. New research based at Princeton University shows that the trick to more precise forecasts is to follow local temperature changes.

The researchers report in the journal Science the first evidence that sea creatures consistently keep pace with “climate velocity,” or the speed and direction in which changes such as ocean temperature move. They compiled 43 years of data related to the movement of 128 million animals from 360 species living around North America, including commercial staples such as lobster, shrimp and cod. They found that 70 percent of shifts in animals’ depth and 74 percent of changes in latitude correlated with regional-scale fluctuations in ocean temperature. (more…)

Cool heads likely won’t prevail in a hotter, wetter world

By Guest PostAugust 21, 2013Environmentarchaeology, australia, Berkeley, brazil, China, climate, cool heads, crime, criminology, critical factors, domestic violence, Economics, ethnic minority, ethnic violence, Europe, hotter, human conflict, human history, India, land invasions, marshall burke, middle ages europe, Netherlands, personal violence, point of violence, precipitation, princeton university, psychology, solomon hsiang, somalia, south asia, Tanzania, temperature, united states, university of california, wetter world

Should climate change trigger the upsurge in heat and rainfall that scientists predict, people may face a threat just as perilous and volatile as extreme weather — each other.

Researchers from Princeton University and the University of California-Berkeley report in the journal Science that even slight spikes in temperature and precipitation have greatly increased the risk of personal violence and social upheaval throughout human history. Projected onto an Earth that is expected to warm by 2 degrees Celsius by 2050, the authors suggest that more human conflict is a likely outcome of climate change. (more…)