Questões de Concurso

What is Alzheimer’s disease?

There are many types and causes of dementia, but Alzheimer’s disease is the most common form, accounting for between 60 and 70 per cent of all cases.  

Common early symptoms of Alzheimer’s include short-term memory loss, apathy and depressed mood, but these symptoms are often just seen as being a part of normal ageing, making early diagnosis difficult. 

Doctors diagnose Alzheimer’s on the basis of medical examination, patient history and cognitive tests, and can use imaging to rule out other forms of dementia. However, a definitive diagnosis of Alzheimer’s is only possible after death, when examination of brain tissue can reveal whether a person had the deposits of amyloid and tau proteins that are characteristic of the condition. 

            Source http://advances.sciencemag.org/content/5/1/eaau3333(adapted)

            Journal reference: Science Advances, DOI: 10.1126/sciadv.aau3333

            This article was updated on 30 January 2019 to add more detail and comment

            Access: April 20th, 2019

Planet’s ocean-plastics problem detailed in 60-year data set

Researchers find evidence of rising plastic pollution in an accidental source: log books for planktonmonitoring instruments. Matthew Warren 

Scientists have uncovered the first strong evidence that the amount of plastic polluting the oceans has risen vastly in recent decades — by analysing 60 years of log books for plankton-tracking vessels. 

Data recorded by instruments known as continuous plankton recorders (CPRs) — which ships have collectively towed millions of kilometres across the Atlantic Ocean — show that the trackers have become entangled in large plastic objects, such as bags and fishing lines, roughly three times more often since 2000 than in preceding decades.

This is the first time that researchers have demonstrated the rise in ocean plastics using a single, longterm data set, says Erik van Sebille, an oceanographer at Utrecht University in the Netherlands. “I’m excited that this has been finally done,” he says. The analysis was published on 16 April in Nature Communications. 

 Although the findings are unsurprising, long-term data on ocean plastics had been scant: previous studies looked mainly at the ingestion of plastic by sea creatures over shorter timescales, the researchers say.

Fishing for data

CPRs are torpedo-like devices that have been used since 1931 to survey plankton populations, by filtering the organisms from the water using bands of silk. Today, volunteer ships such as ferries and container ships tow a fleet of CPRs around the world’s oceans. 

(…)Each time a ship tows a CPR, the crew fills in a log book and notes any problems with the device. So Ostle and her colleagues looked through all tow logs from the North Atlantic between 1957 and 2016, to determine whether plastic entanglements have become more common.

Evidence analysis

(…)Van Sebille says that because the study focused on large plastic items, it doesn’t reveal much about the quantity of microplastics — fragments fewer than 5 millimetres long — in the oceans. These tiny contaminants come from sources such as disposable plastic packaging, rather than from fishing gear.

Nevertheless, he adds, the study demonstrates that fisheries play a major part in plastic pollution, and will provide useful baseline data for tracking whether policy changes affect the levels of plastic in the oceans. “As fisheries become more professional, especially in the North Sea, hopefully we might see a decrease,” he says.

Source: https://www.nature.com/articles/d41586-019-01252-0 (adapted).

Access: April 20th, 2019