Cambridge

Views needed on proposed changes to Shopmobility service

Cambridge Council Feed - Wed, 01/17/2018 - 09:19

USERS of Cambridge City Council’s Shopmobility service, which operates from the Grand Arcade and Grafton East car parks, are being encouraged to give their views on proposed changes to the way it is financed, after councillors opted to introduce some charges for users.

The introduction of membership fees and hire charges for use of equipment will cover a loss of funding from Cambridgeshire County Council of £49,500. Members of the service would be eligible for a 50% reduction in hire charges.

Categories: Cambridge, Cambridgeshire

How incurable mitochondrial diseases strike previously unaffected families

Cambridge University NewsFeed - Mon, 01/15/2018 - 16:00

Mitochondrial diseases caused by mutations in mitochondrial DNA are rare, affecting approximately 1 in 10,000 births, but can cause severe conditions. For example, Leigh Syndrome is a severe brain disorder causing progressive loss of mental and movement abilities, which usually becomes apparent in the first year of life and typically results in death within two to three years.

Mitochondria are the powerhouses inside our cells, producing energy and carrying their own DNA instructions (separate from the DNA in the nucleus of every cell). Mitochondria are inherited from a person’s mother via the egg.

In the study, published in Nature Cell Biology, the researchers isolated mouse and human female embryonic germ cells – the cells that will go on to be egg cells in an adult woman – and tested their mitochondrial DNA.

They found that a variety of mutations were present in the mitochondrial DNA in the developing egg cells of all 12 of the human embryos studied, showing that low levels of mitochondrial DNA mutations are carried by healthy humans.

Professor Patrick Chinnery, from the MRC Mitochondrial Biology Unit and the Department of Clinical Neurosciences at the University of Cambridge, said: “We know that these devastating mitochondrial mutations can pop up in families without any previous history, but previously we didn’t know how that happened. We were surprised to find that egg cells in healthy females all carry a few defects in their mitochondrial DNA.”

For most of the human genome, mutations are kept in check by the processes of sexual reproduction, when eggs and sperm combine; however, mitochondria replicate asexually and mitochondrial DNA is inherited unchanged from the mother’s egg. This means that over time mutations can accumulate which, if left unchecked over generations, could eventually lead to malfunction and disease in offspring.

This conundrum led researchers to predict that a “bottleneck,” where only healthy mitochondria survive, may explain how mitochondria are kept healthy down the generations.

In this study, the researchers identified and measured this bottleneck for the first time in developing human egg cells. In these cells, the number of mitochondria decreased to approximately 100 mitochondria per cell, compared to around 100,000 mitochondria in a mature egg cell.

In a mature cell, a few faulty mitochondria could hide unnoticed amongst the thousands of healthy mitochondria, but the small number of mitochondria in the cell during the bottleneck means that the effects of faulty mitochondria are no longer masked.

The exact mechanism by which cells with unhealthy mitochondria are eliminated is not yet known, but since developing egg cells need a lot of energy - produced by the mitochondria - the researchers suggest that after the bottleneck stage, eggs cells containing damaged mitochondria cannot generate enough energy to mature and are lost.                                            

This study found every developing egg cell may carry a few faulty mitochondria, so occasionally, by chance, after the bottleneck these could be the mitochondria that repopulate the egg cell. The scientists suggest that if the quality-control step fails, then this faulty egg could survive and develop into a child with a mitochondrial disease.

Professor Patrick Chinnery said: “Unfortunately, the purification process is not perfect, and occasionally defective mitochondria leak through. This can cause a severe disease in a child, despite no one else in the family having been affected.”

Mitochondrial diseases are currently incurable, although a new IVF technique of mitochondrial transfer gives families affected by mitochondrial disease the chance of having healthy children – removing affected mitochondria from an egg or embryo and replacing them with healthy ones from a donor.

The study authors also suggest that this process could be relevant for human aging. Professor Chinnery added: “Previously it was assumed that the mitochondrial DNA mutations that have been associated with diseases of ageing, such as Alzheimer’s disease, Parkinson’s disease and other neurodegenerative disorders, happened over a person’s lifetime. This study shows how some of these mutations can be inherited from your mother, potentially predisposing you to late onset brain diseases.”

Professor Chinnery is a Wellcome Trust Senior Research Fellow and the researchers were funded by Wellcome, the Medical Research Council and the National Institute for Health Research.

Dr Nathan Richardson, MRC Head of Molecular and Cellular Medicine, said: “This is an exciting study that reveals important new insights into how mitochondrial diseases develop and are inherited between generations. The researchers have made great use of the tissues available from the MRC-Wellcome Human Developmental Biology Resource (HDBR). The HDBR is an internationally unique biobank resource that provides human embryonic and foetal tissue, donated through elective terminations, facilitating research into a large number of distressing medical disorders, such as mitochondrial diseases.”

Reference
Floros, V et al. Segregation of mitochondrial DNA heteroplasmy through a developmental genetic bottleneck in human embryos. Nature Cell Biology; 15 Jan 2018; DOI: 10.1038/41556-017-0017-8

Researchers have shown for the first time how children can inherit a severe – potentially fatal – mitochondrial disease from a healthy mother. The study, led by researchers from the MRC Mitochondrial Biology Unit at the University of Cambridge, reveals that healthy people harbour mutations in their mitochondrial DNA and explains how cases of severe mitochondrial disease can appear unexpectedly in previously unaffected families.

We know that these devastating mitochondrial mutations can pop up in families without any previous history, but previously we didn’t know how that happened. We were surprised to find that egg cells in healthy females all carry a few defects in their mitochondrial DNAPatrick ChinneryDr David Furness (WellcomeThree mitochondria surrounded by cytoplasm


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Categories: Cambridge, Cambridgeshire

North Pole ice rink attracts around 37,000 visitors

Cambridge Council Feed - Thu, 01/11/2018 - 14:16

THE NORTH Pole ice rink and winter fair on Parker’s Piece once again proved popular with Cambridge residents and visitors.

The ice rink, which was open from November to early January, attracted around 37,000 skaters in total, with around 85,000 visiting the attraction as a whole.

Under the terms of the agreement with Cambridge City Council, the rink and fair are now scheduled to be dismantled and removed by 14 January.

The cost of any remedial work required for grass affected by the North Pole attraction will be met by the operator, Arena Events Ltd.

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Astronomers detect ‘whirlpool’ movement in earliest galaxies

Cambridge University NewsFeed - Wed, 01/10/2018 - 18:00

An international team led by Dr Renske Smit from the Kavli Institute of Cosmology at the University of Cambridge used the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to open a new window onto the distant Universe, and have for the first time been able to identify normal star-forming galaxies at a very early stage in cosmic history with this telescope. The results are reported in the journal Nature, and will be presented at the 231st meeting of the American Astronomical Society.

Light from distant objects takes time to reach Earth, so observing objects that are billions of light years away enables us to look back in time and directly observe the formation of the earliest galaxies. The Universe at that time, however, was filled with an obscuring ‘haze’ of neutral hydrogen gas, which makes it difficult to see the formation of the very first galaxies with optical telescopes.

Smit and her colleagues used ALMA to observe two small newborn galaxies, as they existed just 800 million years after the Big Bang. By analysing the spectral ‘fingerprint’ of the far-infrared light collected by ALMA, they were able to establish the distance to the galaxies and, for the first time, see the internal motion of the gas that fuelled their growth.

“Until ALMA, we’ve never been able to see the formation of galaxies in such detail, and we’ve never been able to measure the movement of gas in galaxies so early in the Universe’s history,” said co-author Dr Stefano Carniani, from Cambridge’s Cavendish Laboratory and Kavli Institute of Cosmology.

The researchers found that the gas in these newborn galaxies swirled and rotated in a whirlpool motion, similar to our own galaxy and other, more mature galaxies much later in the Universe’s history. Despite their relatively small size – about five times smaller than the Milky Way – these galaxies were forming stars at a higher rate than other young galaxies, but the researchers were surprised to discover that the galaxies were not as chaotic as expected.

“In the early Universe, gravity caused gas to flow rapidly into the galaxies, stirring them up and forming lots of new stars – violent supernova explosions from these stars also made the gas turbulent,” said Smit, who is a Rubicon Fellow at Cambridge, sponsored by the Netherlands Organisation for Scientific Research. “We expected that young galaxies would be dynamically ‘messy’, due to the havoc caused by exploding young stars, but these mini-galaxies show the ability to retain order and appear well regulated. Despite their small size, they are already rapidly growing to become one of the ‘adult’ galaxies like we live in today.”

The data from this project on small galaxies paves the way for larger studies of galaxies during the first billion years of cosmic time. The research was funded in part by the European Research Council and the UK Science and Technology Facilities Council (STFC).

Reference:
Renske Smit et al. ‘Rotation in [C II]-emitting gas in two galaxies at a redshift of 6.8.’ Nature (2018). DOI: 10.1038/nature24631

Astronomers have looked back to a time soon after the Big Bang, and have discovered swirling gas in some of the earliest galaxies to have formed in the Universe. These ‘newborns’ – observed as they appeared nearly 13 billion years ago – spun like a whirlpool, similar to our own Milky Way. This is the first time that it has been possible to detect movement in galaxies at such an early point in the Universe’s history. 

We’ve never been able to see the formation of galaxies in such detail, and we’ve never been able to measure the movement of gas in galaxies so early in the Universe’s history.Stefano CarnianiAmanda Smith, University of CambridgeArtist's impression of spinning galaxyResearcher profile: Renske Smit

Dr Renske Smit is a postdoctoral researcher and Rubicon Fellow at the Kavli Institute of Cosmology and is supported by the Netherlands Organisation for Scientific Research. Prior to arriving in Cambridge in 2016, she was a postdoctoral researcher at Durham University and a PhD student at Leiden University in the Netherlands.

Her research aims to understand how the first sources of light in the Universe came to be. In her daily work, she studies images of deep space, taken by telescopes such as the Hubble Space Telescope. To gather data, she sometimes travels to places such as Chile or Hawaii to work on big telescopes.

“In Cambridge, I have joined a team working on the James Webb Space Telescope, the most ambitious and expensive telescope ever built,” she says. “With this telescope, we might be able to see the very first stars for the first time. To have this kind of privileged access to world-leading data is truly a dream come true.

“I would like to contribute to changing the perception of what a science professor looks like. Women in the UK and worldwide are terribly underrepresented in science and engineering and as a result, people may feel women either don’t have the inclination or the talent to do science. I hope that one day I will teach students that don’t feel they represent the professor stereotype and make them believe in their own talent.”


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Harnessing the power of algae: new, greener fuel cells move step closer to reality

Cambridge University NewsFeed - Wed, 01/10/2018 - 11:18

As the global population increases, so too does energy demand. The threat of climate change means that there is an urgent need to find cleaner, renewable alternatives to fossil fuels that do not contribute extensive amounts of greenhouse gases with potentially devastating consequences on our ecosystem. Solar power is considered to be a particularly attractive source as on average the Earth receives around 10,000 times more energy from the sun in a given time than is required by human consumption.

In recent years, in addition to synthetic photovoltaic devices, biophotovoltaics (BPVs, also known as biological solar-cells) have emerged as an environmentally-friendly and low-cost approach to harvesting solar energy and converting it into electrical current. These solar cells utilise the photosynthetic properties of microorganisms such as algae to convert light into electric current that can be used to provide electricity.

During photosynthesis, algae produce electrons, some of which are exported outside the cell where they can provide electric current to power devices. To date, all the BPVs demonstrated have located charging (light harvesting and electron generation) and power delivery (transfer to the electrical circuit) in a single compartment; the electrons generate current as soon as they have been secreted.

In a new technique described in the journal Nature Energy, researchers from the departments of Biochemistry, Chemistry and Physics have collaborated to develop a two-chamber BPV system where the two core processes involved in the operation of a solar cell – generation of electrons and their conversion to power – are separated.

“Charging and power delivery often have conflicting requirements,” explains Kadi Liis Saar, of the Department of Chemistry. “For example, the charging unit needs to be exposed to sunlight to allow efficient charging, whereas the power delivery part does not require exposure to light but should be effective at converting the electrons to current with minimal losses.”

Building a two-chamber system allowed the researchers to design the two units independently and through this optimise the performance of the processes simultaneously.

“Separating out charging and power delivery meant we were able to enhance the performance of the power delivery unit through miniaturisation,” explains Professor Tuomas Knowles from the Department of Chemistry and the Cavendish Laboratory. “At miniature scales, fluids behave very differently, enabling us to design cells that are more efficient, with lower internal resistance and decreased electrical losses.”

The team used algae that had been genetically modified to carry mutations that enable the cells to minimise the amount of electric charge dissipated non-productively during photosynthesis. Together with the new design, this enabled the researchers to build a biophotovoltaic cell with a power density of 0.5 W/m2, five times that of their previous design. While this is still only around a tenth of the power density provided by conventional solar fuel cells, these new BPVs have several attractive features, they say.

"While conventional silicon-based solar cells are more efficient than algae-powered cells in the fraction of the sun’s energy they turn to electrical energy, there are attractive possibilities with other types of materials," says Professor Christopher Howe from the Department of Biochemistry. “In particular, because algae grow and divide naturally, systems based on them may require less energy investment and can be produced in a decentralised fashion."

Separating the energy generation and storage components has other advantages, too, say the researchers. The charge can be stored, rather than having to be used immediately – meaning that the charge could be generated during daylight and then used at night-time.

While algae-powered fuel cells are unlikely to generate enough electricity to power a grid system, they may be particularly useful in areas such as rural Africa, where sunlight is in abundance but there is no existing electric grid system. In addition, whereas semiconductor-based synthetic photovoltaics are usually produced in dedicated facilities away from where they are used, the production of BPVs could be carried out directly by the local community, say the researchers.

“This a big step forward in the search for alternative, greener fuels,” says Dr Paolo Bombelli, from the Department of Biochemistry. “We believe these developments will bring algal-based systems closer to practical implementation.”

The research was supported by the Leverhulme Trust, the Engineering and Physical Sciences Research Council and the European Research Council.

Reference
Saar, KL et al. Enhancing power density of biophotovoltaics by decoupling storage and power delivery. Nature Energy; 9 Jan 2018; DOI: 10.1038/s41560-017-0073-0

A new design of algae-powered fuel cells that is five times more efficient than existing plant and algal models, as well as being potentially more cost-effective to produce and practical to use, has been developed by researchers at the University of Cambridge. 

This a big step forward in the search for alternative, greener fuelsPaolo BombelliKadi Liis SaarArtist' impressionResearcher Profile: Dr Paolo Bombelli

Dr Paolo Bombelli is a post-doctoral researcher in the Department of Biochemistry, where his research looks to utilise the photosynthetic and metabolic activity of plants, algae and bacteria to create biophotovoltaic devices, a sustainable source of renewable current. He describes himself as “a plants, algae and bacteria electrician”.

“Photosynthesis generates a flow of electrons that keeps plants, algae and other photosynthetic organisms alive,” he explains. “These electrons flow though biological wires and, like the electrical current obtained from a battery and used to power a radio, they are the driving force for any cellular activity.”

Dr Bombelli’s fascination with this area of research began during his undergraduate studies at the University of Milan.

“Plants, algae and photosynthetic bacteria are the oldest, most common and effective solar panels on our planet,” he says. “For billions of years they have been harnessing the energy of the sun and using it to provide oxygen, food and materials to support life. With my work I aim to provide new ways to embrace the potential of these fantastic photosynthetic organisms.”

His work is highly cross-disciplinary, with input from the Departments of Biochemistry, Plant Sciences, Chemistry and Physics, and the Institute for Manufacturing, as well as from researchers at Imperial College London, UCL, the University of Brighton, the Institute for Advanced Architecture of Catalonia in Spain and the University of Cape Town, South Africa.

“Universities are great places to work and so they attract many people,” he says. “People choose to come to Cambridge because they know the ideas they generate here will go on to change the world.”

In 2016, Dr Bombelli won a Public Engagement with Research Award by the University of Cambridge for his work engaging audiences at more than 40 public events, including science festivals and design fairs, reaching thousands of people in seven countries. His outreach work included working with Professor Chris Howe to develop a prototype ‘green bus shelter’ where plants, classical solar panels and bio-electrochemical systems operate in synergy in a single structure.


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Review of Empty Homes Policy outlines help available to owners of empty properties

Cambridge Council Feed - Tue, 01/09/2018 - 10:08

CAMBRIDGE City Council is set to review its Empty Homes Policy which sets  out the action it takes in relation to empty properties in Cambridge – whether through assistance and advice or through formal enforcement..

The revised policy includes the assistance the council can offer owners of long-term empty homes including the recently introduced interest-free loans scheme which offers property owners up to £25,000 to pay for renovations.

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Voluntary groups set for £900,000 boost from community grants

Cambridge Council Feed - Tue, 01/09/2018 - 09:29

NEARLY 60 local groups and organisations have been recommended to benefit from funds totalling £900,000 in Cambridge City Council’s Community Grants scheme.

Community Grant funds are aimed at voluntary and community groups working on projects to help reduce social or economic inequality among Cambridge residents with the greatest needs.

Funding will help to provide a variety of services to residents including financial and legal advice, employment support and community, cultural and sporting activities.

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New council homes in the pipeline for former garage sites in King's Hedges and Queen Edith's

Cambridge Council Feed - Mon, 01/08/2018 - 11:00

TWO former garage sites owned by Cambridge City Council will be developed to provide much-needed new council homes, if proposals are approved by Housing Scrutiny Committee.

A site at Markham Close in King’s Hedges ward would see four one-bedroom flats built, while another site at Gunhild Way in Queen Edith’s ward would see two new two-bedroom homes constructed.

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Local groups tackling inequality invited to apply for Area Committee Grants

Cambridge Council Feed - Fri, 01/05/2018 - 13:50

LOCAL groups serving disadvantaged areas and communities in Cambridge could be eligible for grants from Cambridge City Council.

The council’s Area Committee Grants totalling £70,000 are available to groups across the city, including non-profit, voluntary and community organisations, or groups of local residents.

Grants of up to £5,000 are awarded to groups to help fund various aspects of a project benefiting people living in a particular part of the city, such as:

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Council set to review Shopmobility services at multi-storey car parks

Cambridge Council Feed - Fri, 01/05/2018 - 10:28

ANNUAL membership fees and hire charges for use of equipment are among the changes to be considered as part of a review of Cambridge City Council’s Shopmobility service.

The review is being carried out to ensure the service can continue to operate and provide assistance for people with reduced mobility visiting the city centre, despite a loss of funding.

Shopmobility currently operates at no charge for customers from Grand Arcade and Grafton East multi-storey car parks, whereas most similar services in the UK charge their users.

Categories: Cambridge, Cambridgeshire

Have your say on Local Plan modifications

Cambridge Council Feed - Fri, 01/05/2018 - 09:18

A six-week public consultation has begun on proposed modifications to the draft Local Plans for South Cambridgeshire and Cambridge.

Independently-appointed Planning Inspectors have reviewed the two Local Plans submitted by Cambridge City Council and South Cambridgeshire District Council, held hearings and visited sites. They have now asked for a consultation to be carried out on some proposed modifications.

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Advances in brain imaging settle debate over spread of key protein in Alzheimer’s

Cambridge University NewsFeed - Fri, 01/05/2018 - 00:05

An estimated 44 million people worldwide are living with Alzheimer’s disease, a disease whose symptoms include memory problems, changes in behaviour and progressive loss of independence. These symptoms are caused by the build-up in the brain of two abnormal proteins: amyloid beta and tau. It is thought that amyloid beta occurs first, encouraging the appearance and spread of tau – and it is this latter protein that destroys the nerve cells, eating away at our memories and cognitive functions.

Until a few years ago, it was only possible to look at the build-up of these proteins by examining the brains of Alzheimer’s patients who had died, post mortem. However, recent developments in positron emission tomography (PET) scanning have enabled scientists to begin imaging their build-up in patients who are still alive: a patient is injected with a radioactive ligand, a tracer molecule that binds to the target (tau) and can be detected using a PET scanner.

In a study published today in the journal Brain, a team led by scientists at the University of Cambridge describe using a combination of imaging techniques to examine how patterns of tau relate to the wiring of the brain in 17 patients with Alzheimer’s disease, compared to controls.

Quite how tau appears throughout the brain has been the subject of speculation among scientists. One hypothesis is that harmful tau starts in one place and then spreads to other regions, setting off a chain reaction. This idea – known as ‘transneuronal spread’ – is supported by studies in mice. When a mouse is injected with abnormal human tau, the protein spreads rapidly throughout the brain; however, this evidence is controversial as the amount of tau injected is much higher relative to brain size compared to levels of tau observed in human brains, and the protein spreads rapidly throughout a mouse’s brain whereas it spreads slowly throughout a human brain.

There are also two other competing hypotheses. The ‘metabolic vulnerability’ hypothesis says that tau is made locally in nerve cells, but that some regions have higher metabolic demands and hence are more vulnerable to the protein. In these cases tau is a marker of distress in cells.

The third hypothesis, ‘trophic support’, also suggests that some brain regions are more vulnerable than others, but that this is less to do with metabolic demand and more to do with a lack of nutrition to the region or with gene expression patterns.

Thanks to the developments in PET scanning, it is now possible to compare these hypotheses.

“Five years ago, this type of study would not have been possible, but thanks to recent advances in imaging, we can test which of these hypotheses best agrees with what we observe,” says Dr Thomas Cope from the Department of Clinical Neurosciences at the University of Cambridge, the study’s first author.

Dr Cope and colleagues looked at the functional connections within the brains of the Alzheimer’s patients – in other words, how their brains were wired up – and compared this against levels of tau. Their findings supported the idea of transneuronal spread, that tau starts in one place and spreads, but were counter to predictions from the other two hypotheses.

“If the idea of transneuronal spread is correct, then the areas of the brain that are most highly connected should have the largest build-up of tau and will pass it on to their connections. It’s the same as we might see in a flu epidemic, for example – the people with the largest networks are most likely to catch flu and then to pass it on to others. And this is exactly what we saw.”

Professor James Rowe, senior author on the study, adds: “In Alzheimer’s disease, the most common brain region for tau to first appear is the entorhinal cortex area, which is next to the hippocampus, the ‘memory region’. This is why the earliest symptoms in Alzheimer’s tend to be memory problems. But our study suggests that tau then spreads across the brain, infecting and destroying nerve cells as it goes, causing the patient’s symptoms to get progressively worse.”

Confirmation of the transneuronal spread hypothesis is important because it suggests that we might slow down or halt the progression of Alzheimer’s disease by developing drugs to stop tau from moving along neurons.

The same team also looked at 17 patients affected by another form of dementia, known as progressive supranuclear palsy (PSP), a rare condition that affects balance, vision and speech, but not memory. In PSP patients, tau tends to be found at the base of the brain rather than throughout. The researchers found that the pattern of tau build-up in these patients supported the second two hypotheses, metabolic vulnerability and trophic support, but not the idea that tau spreads across the brain.

The researchers also took patients at different stages of disease and looked at how tau build-up affected the connections in their brains.

In Alzheimer’s patients, they showed that as tau builds up and damages networks, the connections become more random, possibly explaining the confusion and muddled memories typical of such patients.

In PSP, the ‘highways’ that carry most information in healthy individuals receives the most damage, meaning that information needs to travel around the brain along a more indirect route. This may explain why, when asked a question, PSP patients may be slow to respond but will eventually arrive at the correct answer.

The study was funded by the NIHR Cambridge Biomedical Research Centre, the PSP Association, Wellcome, the Medical Research Council, the Patrick Berthoud Charitable Trust and the Association of British Neurologists.

Reference
Cope, TE et al. Tau Burden and the Functional Connectome in Alzheimer's Disease and Progressive Supranuclear Palsy. Brain; 5 Jan 2018; DOI: 10.1093/brain/awx347

Recent advances in brain imaging have enabled scientists to show for the first time that a key protein which causes nerve cell death spreads throughout the brain in Alzheimer’s disease – and hence that blocking its spread may prevent the disease from taking hold.

Global PanoramaAlzheimer's patients & carers


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New measures proposed to improve city markets

Cambridge Council Feed - Thu, 01/04/2018 - 17:03

CHANGES to operating regulations and to fees and charges at city markets are being proposed by Cambridge City Council.

In a report to the Environment Scrutiny Committee on 16 January, the council is proposing to update the Charter Market Regulations which govern how the council’s General and Sunday Market operates. The proposed changes are being made following a period of consultation of market traders at the end of last year.

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Car park charging proposals aim to help cut congestion and air pollution

Cambridge Council Feed - Thu, 01/04/2018 - 16:10

PARKING charges at Cambridge City Council’s car parks are set to change from April, as part of the council’s plan to cut congestion, air pollution and carbon emissions.

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City council budget plans biggest programme of asset investment for over a decade, and expands support for people in most need

Cambridge Council Feed - Thu, 01/04/2018 - 15:22

MAJOR capital investment including 500 new council homes, significant council land redevelopment, and investment in digital technology and CCTV are the centrepiece of the Cambridge City Council annual Budget Report published today, the biggest council investment in its major sites and community assets for well over a decade.

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Direct genetic evidence of founding population reveals story of first Native Americans

Cambridge University NewsFeed - Wed, 01/03/2018 - 18:00

The data, which came from archaeological finds in Alaska, also points to the existence of a previously unknown Native American population, whom academics have named “Ancient Beringians”.

The findings are being published in the journal Nature and present possible answers to a series of long-standing questions about how the Americas were first populated.

It is widely accepted that the earliest settlers crossed from what is now Russia into Alaska via an ancient land bridge spanning the Bering Strait which was submerged at the end of the last Ice Age. Issues such as whether there was one founding group or several, when they arrived, and what happened next, are the subject of extensive debate, however.

In the new study, an international team of researchers led by academics from the Universities of Cambridge and Copenhagen sequenced the full genome of an infant – a girl named Xach'itee'aanenh t'eede gay, or Sunrise Child-girl, by the local Native community - whose remains were found at the Upward Sun River archaeological site in Alaska in 2013.

To their surprise, they found that although the child had lived around 11,500 years ago, long after people first arrived in the region, her genetic information did not match either of the two recognised branches of early Native Americans, which are referred to as Northern and Southern. Instead, she appeared to have belonged to an entirely distinct Native American population, which they called Ancient Beringians.

Further analyses then revealed that the Ancient Beringians were an offshoot of the same ancestor population as the Northern and Southern Native American groups, but that they separated from that population earlier in its history. This timeline allowed the researchers to construct a picture of how and when the continent might have been settled by a common, founding population of ancestral Native Americans, that gradually divided into these different sub-groupings.

The study was led by Professor Eske Willerslev, who holds positions both at St John’s College, University of Cambridge, and the University of Copenhagen in Denmark.

“The Ancient Beringians diversified from other Native Americans before any ancient or living Native American population sequenced to date. It’s basically a relict population of an ancestral group which was common to all Native Americans, so the sequenced genetic data gave us enormous potential in terms of answering questions relating to the early peopling of the Americas,” he said. 

“We were able to show that people probably entered Alaska before 20,000 years ago. It’s the first time that we have had direct genomic evidence that all Native Americans can be traced back to one source population, via a single, founding migration event.”

The study compared data from the Upward Sun River remains with both ancient genomes, and those of numerous present-day populations. This allowed the researchers first to establish that the Ancient Beringian group was more closely related to early Native Americans than their Asian and Eurasian ancestors, and then to determine the precise nature of that relationship and how, over time, they split into distinct populations.

Until now, the existence of two separate Northern and Southern branches of early Native Americans has divided academic opinion regarding how the continent was populated. Researchers have disagreed over whether these two branches split after humans entered Alaska, or whether they represent separate migrations.

The Upward Sun River genome shows that Ancient Beringians were isolated from the common, ancestral Native American population, both before the Northern and Southern divide, and after the ancestral source population was itself isolated from other groups in Asia. The researchers say that this means it is likely there was one wave of migration into the Americas, with all subdivisions taking place thereafter.

According to the researchers’ timeline, the ancestral population first emerged as a separate group around 36,000 years ago, probably somewhere in northeast Asia. Constant contact with Asian populations continued until around 25,000 years ago, when the gene flow between the two groups ceased. This cessation was probably caused by brutal changes in the climate, which isolated the Native American ancestors. “It therefore probably indicates the point when people first started moving into Alaska,” Willerslev said.

Around the same time, there was a level of genetic exchange with an ancient North Eurasian population. Previous research by Willerslev has shown that a relatively specific, localised level of contact between this group, and East Asians, led to the emergence of a distinctive ancestral Native American population.

Ancient Beringians themselves then separated from the ancestral group earlier than either the Northern or Southern branches around 20,000 years ago. Genetic contact continued with their Native American cousins, however, at least until the Upward Sun River girl was born in Alaska around 8,500 years later.

The geographical proximity required for ongoing contact of this sort led the researchers to conclude that the initial migration into the Americas had probably already taken place when the Ancient Beringians broke away from the main ancestral line. José Víctor Moreno-Mayar, from the University of Copenhagen, said: “It looks as though this Ancient Beringian population was up there, in Alaska, from 20,000 years ago until 11,500 years ago, but they were already distinct from the wider Native American group.”

Finally, the researchers established that the Northern and Southern Native American branches only split between 17,000 and 14,000 years ago which, based on the wider evidence, indicates that they must have already been on the American continent south of the glacial ice.

The divide probably occurred after their ancestors had passed through, or around, the Laurentide and Cordilleran ice sheets – two vast glaciers which covered what is now Canada and parts of the northern United States, but began to thaw at around this time.

The continued existence of this ice sheet across much of the north of the continent would have isolated the southbound travellers from the Ancient Beringians in Alaska, who were eventually replaced or absorbed by other Native American populations. Although modern populations in both Alaska and northern Canada belong to the Northern Native American branch, the analysis shows that these derive from a later “back” migration north, long after the initial migration events.

“One significant aspect of this research is that some people have claimed the presence of humans in the Americas dates back earlier – to 30,000 years, 40,000 years, or even more,” Willerslev added. “We cannot prove that those claims are not true, but what we are saying, is that if they are correct, they could not possibly have been the direct ancestors to contemporary Native Americans.”

Reference:

Willerslev, E, et al. Terminal Pleistocene Alaskan genome reveals first founding population of Native Americans. Nature. 3 Jan 2018. DOI: 10.1038/nature25173

Direct genetic traces of the earliest Native Americans have been identified for the first time in a new study. The genetic evidence suggests that people may have entered the continent in a single migratory wave, perhaps arriving more than 20,000 years ago.

It’s the first time that we have had direct genomic evidence that all Native Americans can be traced back to one source population, via a single, founding migration eventEske WillerslevBen Potter.Excavations at the Upward Sun River archaeological site in Alaska. The new study shows that the remains found there belonged to members of a previously unknown Native American population, whom academics have named “Ancient Beringians”.


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