(Press-News.org) This news release is available in German.
The distance between the Earth and the Sun has no influence on the decay rate of radioactive chlorine. You could ask: "And why should it anyway?", because it is well known that the decay of radionuclides is as reliable as a Swiss clock. Recently, US-American scientists, however, attracted attention when they postulated that the decay rate depends on the flow of solar neutrinos and, thus, also on the distance from the Earth to the Sun. Their assumption was based, among other things, on older measurement data of the Physikalisch-Technische Bundesanstalt (PTB). PTB researchers have now definitively refuted the assumption of the Americans.
The half-life of radioactive isotopes, i.e. the period in which half of all atomic nuclei have decayed, is regarded as invariably stable. In the case of the carbon isotope 14C, this period amounts, for example, to 5700 years. This property is, among other things, made use of for the dating of archeological findings. There was great excitement when a group of US-American scientists recently published measurement data of the radioactive isotope 36Cl which showed seasonal variations and explained this with the influence of solar neutrinos. All the more since billions of neutrinos from the Sun hit every square centimetre of the Earth every second and remain almost ineffective (they penetrate the Earth as if it weren't there).
Scientists of the Physikalisch-Technische Bundesanstalt have now carried out new measurements and have published their results in the journal "Astroparticle Physics". For three years, they checked the activity of samples with 36Cl in order to detect possible seasonal dependencies. Whereas the US-Americans had determined the count rates with gas detectors, PTB used the so-called TDCR liquid scintillation method which largely compensates disturbing influences on the measurements. The result: The measurement results of PTB clearly show fewer variations and do not indicate any seasonal dependence or the influence of solar neutrinos. "We assume that other influences are much more probable as the reason for the observed variations", explains PTB physicist Karsten Kossert. "It is known that changes in the air humidity, in the air pressure and in the temperature can definitively influence sensitive detectors."
Meanwhile, the data of another measurement series − this time for the strontium isotope 90Sr − have been evaluated and submitted for publication. Here too, even sophisticated analyzing methods give no indication of seasonal variations. It can thus be assumed that an influence of solar neutrinos on the radioactive decay does not exist − at least not in the order of magnitude postulated.
INFORMATION:
Your contact at PTB
Dr. Karsten Kossert, PTB Working Group 6.11 Unit of Activity, phone: +49(0) 531 592-6110, e-mail: karsten.kossert@ptb.de
Original publications
Karsten Kossert, Ole J. Nähle: Long-term measurements of 36Cl to investigate potential solar influence on the decay rate. Astroparticle Physics 55 (2014) 33-36
Karsten Kossert, Ole J. Nähle: Disproof of solar influence on the decay rates of 90Sr/90Y. To be found under arXiv:1407.2493 [nucl-ex], Preprint
J.H. Jenkins et al.: Additional experimental evidence for a solar influence on nuclear decay rates. Astroparticle Physics 37 (2012) 81-88
Old textbook knowledge reconfirmed: Decay rates of radioactive substances are constant
PTB researchers refute the assumption that the decay rate of some radioactive nuclides depends on the distance between the Earth and the sun
2014-10-10
ELSE PRESS RELEASES FROM THIS DATE:
Mineralization of sand particles boosts microbial water filtration
2014-10-10
WASHINGTON, DC – OCTOBER 10, 2014 - Mineral coatings on sand particles actually encourage microbial activity in the rapid sand filters that are used to treat groundwater for drinking, according to a paper published ahead of print in Applied and Environmental Microbiology. These findings resoundingly refute, for the first time, the conventional wisdom that the mineral deposits interfere with microbial colonization of the sand particles.
"We find an overwhelmingly positive effect of mineral deposits on microbial activity and density," says corresponding author Barth ...
Dangerous blood clots: A serious global problem
2014-10-10
A study on the global burden of venous thromboembolism—when a dangerous clot forms in a blood vessel—found that annual incidences range from 0.75 to 2.69 per 1,000 individuals in the population. The incidence increased to between 2 and 7 per 1,000 among those 70 years of age or more.
"Venous thromboembolism in hospitalized patients was responsible for more years lost due to ill-health than hospital-acquired pneumonia, catheter-related blood stream infections, and side effects from drugs," said Dr. Gary Raskob, co-author of the Journal of Thrombosis & Haemostasis ...
Researchers find RNA molecules in urine and tissue that detect prostate cancer
2014-10-10
Philadelphia, PA, October 9, 2014 – Researchers at Sanford-Burnham Medical Research Institute have identified a set of RNA molecules that are detectable in tissue samples and urine of prostate cancer patients but not in normal healthy individuals. The study sets the stage for the development of more sensitive and specific noninvasive tests for prostate cancer than those currently available, which could result in fewer unnecessary prostate biopsies with less treatment-related morbidity, according to a new study in The Journal of Molecular Diagnostics.
According to ...
Stanford team invents sensor that uses radio waves to detect subtle changes in pressure
2014-10-10
Stanford engineers have invented a wireless pressure sensor that has already been used to measure brain pressure in lab mice with brain injuries.
The underlying technology has such broad potential that it could one day be used to create skin-like materials that can sense pressure, leading to prosthetic devices with the electronic equivalent of a sense of touch.
A nine-member research team led by Chemical Engineering Professor Zhenan Bao detailed two medical applications of this technology in Nature Communications.
In one simple demonstration they used this wireless ...
Similar but different: New discovery for degenerative disease
2014-10-10
Researchers from the University of Melbourne have established how two diseases that present in similar ways are in fact quite different.
Progressive Supranuclear palsy and Parkinson's Disease have overlapping symptoms but remain difficult to distinguish.
However, a first ever paper on the topic published in the Journal of Neuropsychology (British Psychological Society publication) now suggests that people with PSP experience more severe and extensive cognitive impairments than those with PD early on.
The study indicates that patients with PSP experience more severe ...
Longer-term outcomes of program to reduce unnecessary antibiotic prescriptions
2014-10-10
The initial benefits of an outpatient antimicrobial stewardship intervention designed to reduce the rate of inappropriate antibiotic prescriptions were lost after discontinuation of audit and feedback to clinicians, according to a study published in JAMA. The study is being released early online to coincide with the IDWeek 2014 meeting.
Antibiotics are the most frequently prescribed medications for children; most are prescribed for outpatient acute respiratory tract infections. Because antibiotic prescribing is often inappropriate, Jeffrey S. Gerber, M.D., Ph.D., of ...
An unexpected bonus
2014-10-10
The so-called Signal Transducers and Activators of Transcription, or STATs, are key components of many different signalling pathways. Not surprisingly, then, when something goes wrong with their regulation the consequences can be severe and many types of cancer are known to be associated with increased activities of one or more STAT protein. STAT3 is a frequent culprit and is often found to be activated in tumour cells.
Considerable efforts are going into developing inhibitors of STAT3 for use in cancer therapy but it is unclear whether these will turn out to be suitable ...
Professor examines terrorist propaganda
2014-10-10
New research out of Queen's University could give insight into what terrorists are thinking. Professor David Skillicorn (School of Computing) analyzed language used in two jihadist magazines to gain intelligence about terrorist strategy.
He examined the language used in Inspire, an online magazine reportedly published by al-Qaida in the Arabian Peninsula, which aims to increase the availability of their message, and the Islamic State News published by ISIS. Inspire has attracted attention because of its goal of attracting lone-wolf attacks in Western countries.
"The payoff ...
Fingolimod in new therapeutic indication: Added benefit not proven
2014-10-10
The immunosuppressive drug fingolimod (trade name: Gilenya) was approved for an expanded therapeutic indication in May 2014: It is now also available for adults with highly active relapsing remitting multiple sclerosis (RRMS) who had received other pretreatment than interferon beta (IFN-β). In an early benefit assessment pursuant to the Act on the Reform of the Market for Medicinal Products (AMNOG), the German Institute for Quality and Efficiency in Health Care (IQWiG) examined whether the drug offers an added benefit over the appropriate comparator therapy in this ...
Mechanism that repairs brain after stroke discovered
2014-10-10
A previously unknown mechanism through which the brain produces new nerve cells after a stroke has been discovered at Lund University and Karolinska Institute in Sweden. The findings have been published in the journal SCIENCE.
A stroke is caused by a blood clot blocking a blood vessel in the brain, which leads to an interruption of blood flow and therefore a shortage of oxygen. Many nerve cells die, resulting in motor, sensory and cognitive problems.
The researchers have shown that following an induced stroke in mice, support cells, so-called astrocytes, start to form ...
LAST 30 PRESS RELEASES:
Multi-resistance in bacteria predicted by AI model
Tinker Tots: A citizen science project to explore ethical dilemmas in embryo selection
Sensing sickness
Cost to build multifamily housing in California more than twice as high as in Texas
Program takes aim at drinking, unsafe sex, and sexual assault on college campuses
Inability to pay for healthcare reaches record high in U.S.
Science ‘storytelling’ urgently needed amid climate and biodiversity crisis
KAIST Develops Retinal Therapy to Restore Lost Vision
Adipocyte-hepatocyte signaling mechanism uncovered in endoplasmic reticulum stress response
Mammals were adapting from life in the trees to living on the ground before dinosaur-killing asteroid
Low LDL cholesterol levels linked to reduced risk of dementia
Thickening of the eye’s retina associated with greater risk and severity of postoperative delirium in older patients
Almost one in ten people surveyed report having been harmed by the NHS in the last three years
Enhancing light control with complex frequency excitations
New research finds novel drug target for acute myeloid leukemia, bringing hope for cancer patients
New insight into factors associated with a common disease among dogs and humans
Illuminating single atoms for sustainable propylene production
New study finds Rocky Mountain snow contamination
Study examines lactation in critically ill patients
UVA Engineering Dean Jennifer West earns AIMBE’s 2025 Pierre Galletti Award
Doubling down on metasurfaces
New Cedars-Sinai study shows how specialized diet can improve gut disorders
Making moves and hitting the breaks: Owl journeys surprise researchers in western Montana
PKU Scientists simulate the origin and evolution of the North Atlantic Oscillation
ICRAFT breakthrough: Unlocking A20’s dual role in cancer immunotherapy
How VR technology is changing the game for Alzheimer’s disease
A borrowed bacterial gene allowed some marine diatoms to live on a seaweed diet
Balance between two competing nerve proteins deters symptoms of autism in mice
Use of antifungals in agriculture may increase resistance in an infectious yeast
Awareness grows of cancer risk from alcohol consumption, survey finds
[Press-News.org] Old textbook knowledge reconfirmed: Decay rates of radioactive substances are constantPTB researchers refute the assumption that the decay rate of some radioactive nuclides depends on the distance between the Earth and the sun