Dicembre 2025

Lo studio mostra come l'eventuale rilevazione degli echi gravitazionali possa fornire nuovi indizi sulla teoria della gravità di Einstein

Nello studio appena pubblicato sulla rivista “Nature Astronomy” i ricercatori Paolo Pani del dipartimento di Fisica della Sapienza e Vitor Cardoso dell'Instituto Superior Técnico di Lisbona discutono di come, alla luce di nuovi modelli teorici, l'astronomia gravitazionale possa fornire informazioni sulla natura dei cosiddetti “oggetti compatti”, termine col quale in astrofisica vengono indicate grandi masse concentrate in dimensioni molto ridotte, come i buchi neri. Le onde gravitazionali contengono informazioni sulla natura degli oggetti compatti, proprio come le onde sonore prodotte da uno strumento musicale dipendono dalle proprietà di quest'ultimo: forma, dimensione, materiale. La loro rilevazione, meno di due anni fa, ha rappresentato una importantissima conferma della teoria di Einstein e ha aperto la strada a un nuovo capitolo della fisica. Secondo la teoria della relatività generale di Einstein, una stella massiccia alla fine del suo ciclo di vita collassa sotto il suo stesso peso e forma un "buco nero", un oggetto che distorce lo spazio-tempo in maniera così drastica che nemmeno la luce è in grado di uscire dal suo "orizzonte degli eventi", cioè la regione oltre la quale non è più possibile osservare un fenomeno. Nuovi modelli teorici suggeriscono che l’eventuale presenza di “echi gravitazionali”, se rilevati dagli interferometri LIGO e Virgo, potrebbe indicare che i buchi neri non sono come fino a oggi ipotizzato: vari modelli di gravità quantistica prevedono che l'orizzonte degli eventi non si formi e che il collasso gravitazionale termini con la formazione di un oggetto esotico compatto e non un vero e proprio buco nero.

Pubblicato in Astrofisica

Mercoledì, 27 Settembre 2017 08:29

Some marine species more vulnerable to climate change than others

Certain marine species will fare much worse than others as they become more vulnerable to the effects of climate change, a new UBC study has found. After analyzing the biological characteristics of 1,074 marine fish and shellfish, the study identified 294 species that are most at-risk due to climate change by 2050. Species most at-risk include the Eastern Australian salmon, yellowbar angelfish, toli shad, sohal surgeonfish and spotted grouper. “We hope that this study will highlight the marine species that are most in need of management and conservation actions under climate change,” said William Cheung, associate professor in the Institute for the Oceans and Fisheries and director of science for the Nippon Foundation – UBC Nereus Program.

Pubblicato in Scienceonline

Lunedì, 25 Settembre 2017 15:55

Three or More Cups of Coffee Daily Halves Mortality Risk in Patients with Both HIV and HCV

Novel five-year study highlights importance of behaviors such as coffee drinking and not smoking on health and survival of HIV-infected patients, report investigators in the Journal of Hepatology. Patients infected by both human immunodeficiency virus (HIV) and hepatitis C virus (HCV) are at specific risk of end-stage liver disease and greater risk of cardiovascular diseases and cancer. In addition, HIV infection accelerates the progression of chronic hepatitis C to fibrosis and development of cirrhosis and end-stage liver disease. In these HIV-HCV co-infected patients, drinking at least three cups of coffee each day halved the risk of all-cause mortality according to a new study published in the Journal of Hepatology. This study is the first to investigate the relationship between coffee consumption and the risk of all-cause mortality in HIV-HCV co-infected patients. “This is a very exciting time for HCV research as a cure that can eradicate the virus is now available for all patients,” explained lead investigator Dominique Salmon-Céron, MD, PhD, of the Service des Maladies Infectieuses et Tropicales, Hôpital Cochin, and Université Paris Descartes, Paris, France. “However, even when cured of HCV, patients co-infected with HIV have a higher risk of death with respect to the general population, due to an accelerated aging process that may result from cancer, complications related to diabetes and to liver disease, and from cardiovascular events.”

Pubblicato in Scienceonline

Lunedì, 25 Settembre 2017 13:18

Brain damage in fish affected by plastic nanoparticles

A new study from Lund University in Sweden shows that plastic particles in water may end up inside fish brains. The plastic can cause brain damage, which is the likely cause of behavioural disorders observed in the fish. Calculations have shown that 10 per cent of all plastic produced around the world ultimately ends up in the oceans. As a result, a large majority of global marine debris is in fact plastic waste. Human production of plastics is a well-known environmental concern, but few studies have studied the effects of tiny plastic particles, known as nanoplastic particles. “Our study is the first to show that nanosized plastic particles can accumulate in fish brains”, says Tommy Cedervall, a chemistry researcher at Lund University. The Lund University researchers studied how nanoplastics may be transported through different organisms in the aquatic ecosystem, i.e. via algae and animal plankton to larger fish. Tiny plastic particles in the water are eaten by animal plankton, which in turn are eaten by fish.

Pubblicato in Scienceonline

Lunedì, 25 Settembre 2017 08:50

New treatment for chronic throat irritation and globus sensation in the gullet

For the first time in the world, the new radiofrequency ablation technique has been successfully used in severe cases

Chronic throat irritation, a permanent globus sensation, a sore or dry sensation in the throat are common symptoms, which are often trivialised and wrongly attributed to gastro-oesophageal reflux disease. However, these are also the characteristic symptoms of patients suffering from displaced gastric mucosa in the oesophagus (ectopic mucosa). The recent study conducted by researchers from MedUni Vienna and Vienna General Hospital has now brought a break-through in the treatment of patients with this condition. For the first time in the world, the new radiofrequency ablation technique has been successfully used in severe cases.

The symptoms are caused by a section of misplaced gastric mucosa, which is found in the oesophagus rather than as normal in the stomach during gastroscopy in nearly 10 – 15% of people and this results in chronic damage to the larynx due to the production of acid and mucous. Up until now there has been no safe and effective option for treating pronounced forms of this condition. The first application of radiofrequency ablation brings about a significant improvement in the condition. The study has now been published in the leading journal "Digestive Endoscopy".

Pubblicato in Scienceonline

Lunedì, 25 Settembre 2017 08:43

Diabetes medicine reduces Parkinson’s risk

Charalampos Tzoulis (right) and his colleagues, Kristoffer Haugarvoll (left) and Brage Brakedal, hope they are one step closer to a cure for Parkinson´s disease. Photo: Kim E. Andreassen

A Norwegian study shows that the taking of diabetes medicine reduces the risk of getting Parkinson´s disease.
Researchers at the Department of Clinical Medicine at the University of Bergen (UiB) have discovered that medical treatment against diabetes reduces the risk of getting Parkinson´s disease by 35 per cent. “We have made an important discovery, which takes us a step further towards solving the Parkinson´s riddle,” says researcher Charalampos Tzoulis. He has lead the study together with researcher Kristoffer Haugarvoll at the same department.

One step further

Tzoulis says that the researchers have to do follow-up studies on the diabetes medicine to fully understand why it protects against Parkinson´s disease. “If we understand the mechanisms behind the protection, then we have a chance to develop a new treatment,” Tzoulis says.

Influence the cell´s powerhouse

The researchers believe that the diabetes medicines, containing so-called glitazones, are influencing the cells to produce more mitochondria. Mitochondria are the powerhouse of the cells, transforming nutrients that the cells need to work. Tzoulis´research group has previously shown that the production of mitochondria decreases during Parkinson´s.

100 million prescriptions

To see the connection between diabetes and Parkinson´s, the researchers analysed and compared data from the Norwegian Prescription Data Base. The database has stored information on all use of prescription the last 10 years and contains data on more than 100 million prescriptions.

http://www.uib.no/en/med/110489/diabetes-medicine-reduces-parkinson’s-risk

Pubblicato in Scienceonline

Lunedì, 25 Settembre 2017 07:54

Nel mirtillo un'esplosione di sostanze benefiche per la salute

Che il mirtillo coltivato facesse bene alla salute già si sapeva, è noto infatti essere una straordinaria fonte di composti bioattivi, le antocianine. Tuttavia nei laboratori dell'Istituto Agrario di San Michele all'Adige si è scoperto che questi piccoli frutti contengono altre sostanze molto preziose: i flavonoli glicosidi, in particolare la quercetina, una classe di composti naturali noti per le loro proprietà antiossidanti, anticancerogene e di protezione dalle malattie coronariche.
Lo studio, durato quattro anni e finanziato dalla Provincia autonoma di Trento, è stato pubblicato sulla rivista scientifica americana Journal of food composition and analysis. L'articolo firmato da Urska Vrhovsek, Domenico Masuero, Luisa Palmieri e Fulvio Mattivi riguarda appunto l'identificazione e la quantificazione dei flavonoli glicosidi nelle differenti coltivazioni di mirtillo.

Pubblicato in Medicina

Lunedì, 25 Settembre 2017 07:46

A brain-system that builds confidence in what we see, hear and touch

Behavioral scientists and psychologists use the term “metacognition” to describe our ability to access, report and regulate our own mental states: “thinking about thinking”, “knowing about knowing” “being aware about being aware”, are all higher-order cognitive skills that fit this category. Specifically, metacognition enables the brain to compute a degree of confidence when we perceive events from the external world, such as a sound, light, or touch. The accuracy of confidence estimates is crucial in daily life, for instance when hearing a baby crying, or smelling a gas leak. Confidence estimates also need to combine input from multiple senses simultaneously, for instance when buying a violin based on how it sounds, feels, and looks. From a neuroscience point of view, the way metacognition operates in different senses, and for combination of senses is still a mystery: Does metacognition use the same rules for visual, auditory, or tactile stimuli, or does it use different components of each of sensory domains? The first of these two ideas – i.e. the “common rules” – is known as “supramodality” and it has proven controversial among neuroscientists.

Pubblicato in Scienceonline