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Crescent-shaped dunes called barchans are structures that appear in a wide variety of environments, including beaches and deserts, riverbeds and the seafloor, inside water pipes and oil pipelines, and on the surface of Mars and other sandy planets with an atmosphere. Despite differences in scale varying from ten-centimeter ripples for underwater dunes to kilometer-high mountains for Martian dunes, the dynamics of barchan formation and motion appear to be highly similar everywhere. Research [...]

The treatment of intestinal infections caused by some strains of the bacterium Escherichia coli, present in unsanitized or contaminated foods, may have a new ally. A study published in PNAS reports that the inhibition of prostaglandin E2 (PGE2), a lipid mediator released during the process of infected cell clearance (efferocytosis) in the intestine, enhanced the ability of mice to combat infectious colitis. "Tissue cell death is intense during a bacterial infection. Many immune cells [...]

The cattle tick is controlled by pesticides, invariably leading to the selection of resistant strains. In Brazil, this parasite is currently resistant to a greater or lesser extent to all the commercial pesticides used by cattle farmers. The antiparasitic drug most widely used to control cattle tick populations (as well as human parasites) is ivermectin, a broad-spectrum anthelmintic, acaricide, and insecticide. Brazil's commercial cattle herd totaled 217.7 million animals in 2017, according [...]

The history of the peopling of the Americas has just been interpreted afresh. The largest and most comprehensive study ever conducted on the basis of fossil DNA extracted from ancient human remains found on the continent has confirmed the existence of a single ancestral population for all Amerindian ethnic groups, past and present. Over 17,000 years ago this original contingent crossed the Bering Strait from Siberia to Alaska and began peopling the New World. Fossil DNA shows an affinity [...]

Brazil's Ministry of Health received reports of 11,524 outbreaks of foodborne diseases between 2000 and 2015, with 219,909 individuals falling sick and 167 dying from the diseases in question. Bacteria caused most outbreaks of such illnesses, including diarrhea and gastroenteritis. The most frequent were Salmonella spp., with 31,700 cases diagnosed in the period (14.4% of the total), Staphylococcus aureus (7.4%), and Escherichia coli (6.1%). According to a survey by the Ministry of Social [...]

A group of Brazilian researchers succeeded in preventing allergic asthma from progressing in experimental models by increasing the amount of a protein. This increase, in turn, blocked the CD4+ T lymphocytes responsible for producing a cytokine that triggers a cascade of events resulting in the onset and progression of the disease. This knowledge of how the disease can be resolved in cell cultures and animals will form a basis for the research and development of a drug to control expression of [...]

For sweeping drama, it's hard to beat hydropower from dams - a renewable source of electricity that helped build much of the developed world. Yet five scientists from Michigan State University (MSU) say that behind roaring cascades is a legacy of underestimated costs and overestimated value. The developing world can - and must - turn to better ways to generate hydropower for industry and livelihoods. The case is outlined in "Sustainable hydropower in the 21st century" in this week's [...]

An insect larva found in the caves of Intervales State Park, an Atlantic Rainforest remnant in the municipality of Ribeirão Grande, São Paulo State, Brazil, was initially of no interest to the research group led by biochemist Vadim Viviani , a professor at the Federal University of São Carlos (UFSCar) in Sorocaba. The researchers are investigating bioluminescence, the capacity of living organisms to produce their own light. Nevertheless, the larva of Neoditomyia, a genus of non-luminescent [...]

Beef cattle improvement programs have focused for decades on promoting the rapid growth of calves. Now, the goal is to improve other traits, such as meat tenderness or ribeye muscle area. Researchers at São Paulo State University (UNESP) in Brazil who are studying the genome of the Gir breed of Zebu cattle have identified 35 genes associated with reproduction, milk composition, growth, meat and carcass, health or body conformation traits. This identification is a key step toward the [...]