Research
Group identifies rocks 3 billion years old
Discovery of IG teachers and students was made based on geological mapping
After almost a year of intense studies, a group of professors and fifth-year geology students from Unicamp's Institute of Geosciences (IG) announce the identification of rocks that are more than three billion years old. What's more: considerable evidence of the presence of even older rock cores, 3,6 billion years old, was found in the Bahian cities of Uauá, Santa Luz and Retirolândia.
The information comes from professor Elson Paiva de Oliveira, from the Unicamp Geoscience Institute. He says that, in fact, this is the result of intense research and work. To obtain the result, a geological mapping was carried out in these cities, characterized as one of the oldest regions in Brazil. "This allows Geology students to also have the opportunity to learn a little about the oldest history of our planet", observes the professor. He also adds that, in Brazil, the oldest rock described so far was located in Rio Grande do Norte, and is approximately 3,45 billion years old.
In these locations, through analysis of isotopes in zircons, obtained in laboratories in Australia and the United States, Elson de Oliveira and former doctoral student Edson Mello identified rocks that are 2.983 million and 3.085 million years old. Subsequently, professors Elson, Asit Choudhuri and doctoral student Marcelo Juliano visited these cities, with the purpose of examining the relationships between such ancient rocks.
The results of the find, according to Elson, are being submitted for publication in an internationally circulated magazine and, for educational purposes, the City of Retirolândia was informed about the importance of preserving the site and a plaque was erected.
Elson Oliveira explains that planet Earth was formed approximately 4,5 billion years ago. However, due to its unique evolution, which involved the formation and destruction of the oceans and continental cores initially formed, records of the oldest rocks are identified in a few regions that survived subsequent destruction. Currently, some cores with rocks 3,5 billion years old are found in South Africa, Australia, Greenland, China and North America. The oldest rock of all, 4,05 billion years old, called Acasta Gneiss, was found only in northwestern Canada.
"The most surprising finding of last year, the reason for a report in the important magazine Nature, was the description of grains of minerals, up to 4,4 billion years old, found in Australia, in sedimentary rocks that are three billion years old", explains the professor Elson. These grains revealed, according to him, that in the first 200 million years of Earth's history there was already water on the planet and some continent core, probably quite small. For geologists, it is a great challenge to locate ancient cores of continents and ocean floors, "as they help us understand what our planet was like in the first billion years of its existence", points out the professor.
Research
GHC performs surgery that reduces excessive sweating
Isabel Gardenal
The Hospital das Clínicas of Unicamp (HC) has been correcting hyperhidrosis with 100% effectiveness, a dysfunction in which the sweat glands produce sweat in quantities greater than those necessary to control body temperature. This is a reconstructive surgery – videothoracoscopic sympathectomy – carried out by the team responsible for the first procedure in Campinas. It definitively resolves sweaty hands and armpits, as well as eliminating, in 80% of cases, sweaty feet.
Hyperhidrosis affects around 1% of the world's population. In these cases, people mainly have their hands, or feet, or faces, or armpits, or all at the same time, wet.
Surgical correction consists of making three incisions on each side of the chest, measuring 0,5 to 1 cm, to remove three to four ganglia of the sympathetic neurological chain. This option has been encouraged because it uses small incisions and can be performed in just 1 hour.
This procedure is so effective, says thoracic surgeon Ricardo Kalaf Mussi, from the Faculty of Medical Sciences (FCM), that today this surgery with an open chest is unacceptable. "But he advises that the indication for surgery should be strictly the patient's choice."
According to Kalaf, experience confirms that hyperhidrosis persists with alternative methods, and the patient spends a lot of money on ointments, powders, medications, botox and electrical stimulation. "Although useful, its effects are temporary."
The amount of sweat is controlled by the sympathetic nervous system. Its regulatory centers resemble the shape of rosary beads, starting from the nerves, which reach the skin's sweat glands, stimulating them to produce sweat.
Insulation - Personal contact can be torture for those with sweaty hands. People in this situation tend to be socially isolated. Psychotherapy focused on the case alleviates the embarrassment, leading the patient to live with the fact.
According to psychiatry Maurício Knobel, professor at FCM, these patients present a more serious condition when they become nervous or excited, exercise or when the environmental temperature increases.
Some thoracic surgeons and dermatologists began to make therapeutic attempts and view video sympathectomy as efficient and unique at the moment.
The majority of patients who seek out the offices to solve their problems are women and over the age of 14. Morbidity due to sympathectomy varies from 0,1 to 0,2%. "The technique using video in surgery increases the surgeon's visual field by 20 times and drastically reduces possible complications", argues Kalaf.
