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Brain: ‘Lightning bolts’ show learning in action

Rendering of dendrites in brain (stock image). "We believe our study provides important insights into how the brain deals with vast amounts of information continuously as the brain learns new tasks," says senior study investigator and neuroscientist Wen-Biao Gan, PhD. Credit: © Sergey Nivens / Fotolia
Rendering of dendrites in brain (stock image). “We believe our study provides important insights into how the brain deals with vast amounts of information continuously as the brain learns new tasks,” says senior study investigator and neuroscientist Wen-Biao Gan, PhD.
Credit: © Sergey Nivens / Fotolia

 

 

[dropcap]R[/dropcap]esearchers at NYU Langone Medical Center have captured images of the underlying biological activity within brain cells and their tree-like extensions, or dendrites, in mice that show how their brains sort, store and make sense out of information during learning.

n a study to be published in the journal Nature online March 30, the NYU Langone neuroscientists tracked neuronal activity in dendritic nerve branches as the mice learned motor tasks such as how to run forward and backward on a small treadmill. They concluded that the generation of calcium ion spikes — which appeared in screen images as tiny “lightning bolts” in these dendrites — was tied to the strengthening or weakening of connections between neurons, hallmarks of learning new information.

“We believe our study provides important insights into how the brain deals with vast amounts of information continuously as the brain learns new tasks,” says senior study investigator and neuroscientist Wen-Biao Gan, PhD.

Gan, a professor at NYU Langone and its Skirball Institute for Biomolecular Medicine, says, “we have long wondered how the brain can store new information continuously throughout life without disrupting previously acquired memories. We now know that the generation of calcium spikes in separate branches of nerve cells is critical for the brain to encode and store large quantities of information without interfering with each other.”

Lead study investigator Joseph Cichon, a neuroscience doctoral candidate at NYU Langone, says their discoveries could have important implications for explaining the underlying neural circuit problems in disorders like autism and schizophrenia. Cichon says the team’s next steps are to see if calcium ion spikes are malfunctioning in animal models of these brain disorders.

Among the study’s key findings was that learning motor tasks such as running forward and backward induced completely separate patterns of lightning bolt-like activity in the dendrites of brain cells. These lightning bolts triggered a chain-like reaction, which changed the strength of connections between neurons.

The study also identified a unique cell type in the brain that controlled where the lightning bolts were generated. When these cells were turned off, lightning bolt patterns in the brain were disrupted, and as a result, the animal lost the information it had just learned.


Story Source:

The above story is based on materials provided by NYU Langone Medical Center.Note: Materials may be edited for content and length.


Journal Reference:

  1. Joseph Cichon, Wen-Biao Gan. Branch-specific dendritic Ca2 spikes cause persistent synaptic plasticity. Nature, 2015; DOI: 10.1038/nature14251

Consuming a WebService using LINQ

[dropcap]T[/dropcap]his article demonstrates how to query a Web Service’s public API using LINQ. For this article, I am using the Web Service located at GeoNames. Our code will query the CountryInfo webservice which accepts a Country Code and returns information like the country’s capital, population, currency and so on.
Check out the XML document returned from this service over here http://ws.geonames.org/countryInfo?
Let us get started:

 

Step 1: Create a Console Application. To this application, add a class named ‘Country’ and ‘CountryInfo’. The CountryInfo class has the following definition:
class CountryInfo
{
    public string CountryName { get; set; }
    public long Population { get; set; }
    public string Capital { get; set; }
    public string CurrencyCode { get; set; }
    public float AreaSqKm { get; set; }
}
Step 2: The Country class contains a SearchCountry method that returns an IEnumerable<CountryInfo> as shown below:

 

class Country
{
    public IEnumerable<CountryInfo> SearchCountry(string countryCode)
    {
        string uri = Uri.EscapeUriString(countryCode);
        string url = FormatUrl(uri);
        XDocument xdoc = XDocument.Load(url);
        IEnumerable<CountryInfo> results =
        from cntry in xdoc.Descendants(“country”)
        select new CountryInfo
        {
            CountryName = cntry.Element(“countryName”).Value,
            Capital = cntry.Element(“capital”).Value,
            AreaSqKm = Convert.ToSingle(cntry.Element(“areaInSqKm”).Value),
            Population = Convert.ToInt64(cntry.Element(“population”).Value),
            CurrencyCode = cntry.Element(“currencyCode”).Value
        };
        return results;
    }
    string FormatUrl(string cCode)
    {
        return “http://ws.geonames.org/countryInfo?” +
            “country=” + cCode +
            “&username=christlin”;
    }
}
The code is pretty straightforward. We first create the url with the search string using our FormatUrlmethod. We then use the XDocument.Load to create an XML document from the url. The last step is to loop through the XML document, populate the CountryInfo object and return the results.

 

Step 3: The final step is to code the Main() method to retrieve and display the results from the WebService. Here’s how the Main() method looks
static void Main(string[] args)
{
    Country country = new Country();
    string cntryCode = “IN”;
    IEnumerable<CountryInfo> cntryInfo = country.SearchCountry(cntryCode);
    foreach (var c in cntryInfo)
    {
        Console.WriteLine(“You searched for {0}. “ +
                        “The population of {0} is {1} and its capital is {2}. “ +
                        “The CurrencyCode for {0} is {3} and it’s area in Sq. Km is {4}”,
            c.CountryName, c.Population, c.Capital,
            c.CurrencyCode, c.AreaSqKm);
    }
    Console.ReadLine();
}

 

In the example above, we are passing in the country code ‘IN’ for India. We then loop through an object of IEnumberable<CountryInfo> and print the result on the console. The output looks similar to the following:

 

00130032015 Console Output

 

Well that was a simple example of how to query a webservice using LINQ. I hope you liked this article and I thank you for viewing it. The entire source code of this article can be downloaded here

[wpfilebase tag=file id=1 tpl=download-button /]

Listening to classical music modulates genes

A Finnish study group has investigated how listening to classical music affected the gene expression profiles of both musically experienced and inexperienced participants. All the participants listened to W.A. Mozart's violin concert Nr 3, G-major, K.216 that lasts 20 minutes. Credit: © rubchikova / Fotolia
A Finnish study group has investigated how listening to classical music affected the gene expression profiles of both musically experienced and inexperienced participants. All the participants listened to W.A. Mozart’s violin concert Nr 3, G-major, K.216 that lasts 20 minutes.
Credit: © rubchikova / Fotolia

Although listening to music is common in all societies, the biological determinants of listening to music are largely unknown. According to a new study, listening to classical music enhanced the activity of genes involved in dopamine secretion and transport, synaptic neurotransmission, learning and memory, and down-regulated the genes mediating neurodegeneration. Several of the up-regulated genes were known to be responsible for song learning and singing in songbirds, suggesting a common evolutionary background of sound perception across species.

Listening to music represents a complex cognitive function of the human brain, which is known to induce several neuronal and physiological changes. However, the molecular background underlying the effects of listening to music is largely unknown. A Finnish study group has investigated how listening to classical music affected the gene expression profiles of both musically experienced and inexperienced participants. All the participants listened to W.A. Mozart’s violin concert Nr 3, G-major, K.216 that lasts 20 minutes.

Listening to music enhanced the activity of genes involved in dopamine secretion and transport, synaptic function, learning and memory. One of the most up-regulated genes, synuclein-alpha (SNCA) is a known risk gene for Parkinson’s disease that is located in the strongest linkage region of musical aptitude. SNCA is also known to contribute to song learning in songbirds.

“The up-regulation of several genes that are known to be responsible for song learning and singing in songbirds suggest a shared evolutionary background of sound perception between vocalizing birds and humans,” says Dr. Irma Järvelä, the leader of the study.

In contrast, listening to music down-regulated genes that are associated with neurodegeneration, referring to a neuroprotective role of music.

“The effect was only detectable in musically experienced participants, suggesting the importance of familiarity and experience in mediating music-induced effects,” researchers remark.

The findings give new information about the molecular genetic background of music perception and evolution, and may give further insights about the molecular mechanisms underlying music therapy.


Story Source:

The above story is based on materials provided by Helsingin yliopisto (University of Helsinki). Note: Materials may be edited for content and length.


Journal Reference:

  1. Chakravarthi Kanduri, Pirre Raijas, Minna Ahvenainen, Anju K. Philips, Liisa Ukkola-Vuoti, Harri Lähdesmäki, Irma Järvelä. The effect of listening to music on human transcriptome. PeerJ, 2015; 3: e830 DOI: 

Fast-moving unbound star has broken the galactic speed record

Pictorial representation of a fast-moving unbound star.  Credit: ESA/Hubble, NASA
Pictorial representation of a fast-moving unbound star.
Credit: ESA/Hubble, NASA

A fast-moving unbound star discovered by astronomers at Queen’s University Belfast has broken the galactic speed record.

The unbound star, named US708, is traveling at 1,200 kilometers per second — the fastest speed ever recorded for such an object in our galaxy — meaning it is not held back by gravity and will eventually leave the Milky Way.

US708 is believed to have once been part of a double-star solar system, which also included a massive white dwarf star. The white dwarf is thought to have turned into a ‘thermonuclear supernovae’ and exploded, kicking US708 and sending it hurtling across space.

The discovery of US708 sheds light on the mysterious double-star systems that give rise to thermonuclear explosions. Thermonuclear, or ‘type Ia’, supernovae have long been used to calculate the distances to faraway galaxies — a measurement which helps to determine how the universe is changing and expanding.

Dr Rubina Kotak and Ken Smith, from the Astrophysics Centre at Queen’s University, were part of a team of scientists from countries across the world who made the ground-breaking discovery using data gathered by the Pan-STARRS1 telescope on Mount Haleakala on the Hawaiian island of Maui. Using a range of data gathered over the last 59 years the team were able to determine the full 3-D motion of the star and measure how quickly it is moving across the plane of the sky.

Dr Rubina Kotak, from the Astrophysics Centre at Queen’s University Belfast, said: “It is very exciting to have contributed to this important discovery which is a great example of Queen’s commitment to achieving excellence and advancing knowledge for the benefit of society. It brings us a step closer to solving the type Ia puzzle.”

European Southern Observatory fellow, Stephan Geier, who led the study, said: “Several types of stars have been suspected of causing the explosion of a white dwarf as supernova of type Ia. Until now, none of them could be confirmed. Now we have found a delinquent on the run bearing traces from the crime scene.”

Queen’s University Belfast is a full member of the PS1 science consortium, which carried out this research involving astronomers from ten other institutes dotted across the world. The research was led by Dr Stephan Geier, European Southern Observatory fellow, and comprised contributions from scientists from a number of countries including Germany, USA, the Netherlands, China and the UK.


Story Source:

The above story is based on materials provided by Queen’s University, Belfast.Note: Materials may be edited for content and length.


Journal Reference:

  1. S. Geier, F. Furst, E. Ziegerer, T. Kupfer, U. Heber, A. Irrgang, B. Wang, Z. Liu, Z. Han, B. Sesar, D. Levitan, R. Kotak, E. Magnier, K. Smith, W. S. Burgett, K. Chambers, H. Flewelling, N. Kaiser, R. Wainscoat, C. Waters. The fastest unbound star in our Galaxy ejected by a thermonuclear supernova. Science, 2015; 347 (6226): 1126 DOI: 10.1126/science.1259063

What is Database?

A database is a collection of information that is organized so that it can easily be accessed, managed, and updated. In one view, databases can be classified according to types of content: bibliographic, full-text, numeric, and images.

In computing, databases are sometimes classified according to their organizational approach. The most prevalent approach is the relational database, a tabular database in which data is defined so that it can be reorganized and accessed in a number of different ways. A distributed database is one that can be dispersed or replicated among different points in a network. An object-oriented programming database is one that is congruent with the data defined in object classes and subclasses.

Formally, a “database” refers to a set of related data and the way it is structured or organized. Access to this data is usually provided by a “database management system” (DBMS) consisting of an integrated set of computer software that allows users to interact with one or more databases and provides access to all of the data contained in the database (although restrictions may exist that limit access to particular data). The DBMS provides various functions that allow entry, storage and retrieval of large quantities of information as well as provide ways to manage how that information is organized.

Because of the close relationship between them, the term “database” is often used casually to refer to both a database and the DBMS used to manipulate it.

Outside the world of professional information technology, the term database is often used to refer to any collection of related data (such as a spreadsheet or a card index). This article is concerned only with databases where the size and usage requirements necessitate use of a database management system.

Existing DBMSs provide various functions that allow management of a database and its data which can be classified into four main functional groups:

  • Data definition – Creation, modification and removal of definitions that define the organization of the data.
  • Update – Insertion, modification, and deletion of the actual data.
  • Retrieval – Providing information in a form directly usable or for further processing by other applications. The retrieved data may be made available in a form basically the same as it is stored in the database or in a new form obtained by altering or combining existing data from the database.
  • Administration – Registering and monitoring users, enforcing data security, monitoring performance, maintaining data integrity, dealing with concurrency control, and recovering information that has been corrupted by some event such as an unexpected system failure.

Both a database and its DBMS conform to the principles of a particular database model. “Database system” refers collectively to the database model, database management system, and database.

Physically, database servers are dedicated computers that hold the actual databases and run only the DBMS and related software. Database servers are usually multiprocessorcomputers, with generous memory and RAID disk arrays used for stable storage. RAID is used for recovery of data if any of the disks fail. Hardware database accelerators, connected to one or more servers via a high-speed channel, are also used in large volume transaction processing environments. DBMSs are found at the heart of most database applications. DBMSs may be built around a custom multitasking kernel with built-in networking support, but modern DBMSs typically rely on a standard operating system to provide these functions. Since DBMSs comprise a significant economical market, computer and storage vendors often take into account DBMS requirements in their own development plans.

Databases and DBMSs can be categorized according to the database model(s) that they support (such as relational or XML), the type(s) of computer they run on (from a server cluster to a mobile phone), the query language(s) used to access the database (such as SQL or XQuery), and their internal engineering, which affects performance, scalability, resilience, and security.

How Should I Prepare for Lightning Storms?

Lightning storms, severe storm systems that produce frequent cloud-to-ground lightning strikes, can cause serious damage to structures, trees, power lines and consumer electronics. They may trigger fires or damage tree limbs, which in turn can cause even more structural damage. When local weather stations warn of impending lightning storms, there are a number of actions a person should take in order to protect his or her life and property. People and animals should be moved inside, if possible, away from windows. Electronics should be unplugged so there is no chance of them being damaged by power surges.

person-on-bike-in-lightning-storm
People and pets should go inside homes and buildings during lightning storms to the avoid risk of getting struck.

 

One important step to take before lightning storms arrive is to move all living things indoors. Pets, livestock, and family members all need to be under enough shelter to remain dry, warm, and protected from the elements. Standing under the tallest object in an open area, such as a tree at a golf course, is never a good idea, however. Lightning tends to strike the highest point that will lead the electrical charge to the ground. A covered picnic pavilion or the inside of a car would be much safer during lightning storms than a tree or open field.

The same precautions a person should take for any severe weather event apply to lightning storms. A weather radio with a battery back-up should be turned on for regular updates on the storm’s location and intensity. Candles or battery-powered lamps should be readily available in case of a power failure. Family members should remain in lower levels of the home and stay away from windows. Strong lightning storms often put down significant numbers of lightning strikes and loud thunder, so younger children and pets may need extra attention until the storm subsides.

Many people who own consumer electronic devices such as home computers, stereo systems, DVD players and so on should already have those devices plugged into a power strip featuring surge protection, but there are those who don’t. During lightning storms, a direct lightning strike on a nearby power line can cause a temporary surge in electrical power entering the home’s outlets. A surge protector should automatically detect and filter this extra energy, but appliances plugged directly into unprotected sockets can suffer damage. Before a lightning storm arrives, a person should completely unplug all unnecessary electrical appliances and electronic equipment not protected by a surge protector.

It's best to stay away from standing water, such as an ocean or lake, during lightning storms.
It’s best to stay away from standing water, such as an ocean or lake, during lightning storms.

 

Some home owners invest in lightning grounding systems in order to protect their property during a lightning storm. If a lightning bolt does strike the house, a grounding wire will draw the electrical energy away and into a remote part of the property. The installation of a properly grounded lightning rod can also discourage lightning from striking the roof or a nearby tree.

Fortunately, most lightning storms leave distinctive images on modern weather radar systems, so meteorologists can generally warn viewers of a dangerous storm’s predicted path and intensity. Some radar systems can even detect individual lightning strikes within a storm systems and warn specific areas of the potential for danger. The time to take precautions is long before the actual arrival of the storm, however. Once lightning begins to hit an area, it may be too late to save electronic equipment from receiving damage.

If a driver cannot find suitable shelter or drive out of a dangerous storm system, remaining in the car would not be a bad idea. A car will act as a Faraday cage during a lightning strike, meaning the electrical energy would be directed around the car’s exterior, but occupants would remain safe and insulated. The main goal during a strong lightning storm is not to be the tallest target in the area and to stay away from natural conductors such as standing water or metal fences.

Hail can accompany lightning storms.
Hail can accompany lightning storms.
Faraday cage with bolt of electricity.
Faraday cage with bolt of electricity.
An especially heavy layer of cirrus can indicate an incoming storm system.
An especially heavy layer of cirrus can indicate an incoming storm system.
A lightning rod can help protect a building from lightning strikes.
A lightning rod can help protect a building from lightning strikes.

What Is an Electric Current?

Electric current is measured using an ammeter.
Electric current is measured using an ammeter.

Electric current is the name for the flow of electrons that makes up the movement of electric charge. Current flows when the voltage on one end of a conductor differs from the voltage on the other end of a conductor. A force that most people deal with nearly every day, flowing current includes lighting, electrical power cords, and the surprising shock that comes from shuffling shoes on carpet in dry weather. This force is measured in units called amperes, also called amps.

A ubiquitous presence in modern life, current can be found flowing through conductors. Conductors include metal like aluminum, copper, and steel, but water can also conduct current. Electric current has proved to be quite useful to people, but it can also pose a danger to life and property. As humans are made up largely of water, this means that they can conduct current as well, which puts them at risk for electric injury if they come into contact with a conductor with an electric charge. They can also be injured if they are in contact with a body of water when it has a charge, even if the water is in the form of a small stream or puddle.

When referring to electric current, it is proper to say that the current flows through a conducting object like a wire or appliance, not in it. Insulation like rubber or ceramic is commonly used to keep current from flowing into nearby conductors. While air acts as insulation for wires that do not have contact with conductors, open-air wires must often be insulated at connecting points like transformers or building entry and exit points.

residential-electric-meter

An ampere, or amp, is the standard unit used to measure electric current. On paper, amperes can be calculated from coulombs by dividing the coulombs by one second. Amperes in electric current are measured using a tool called an ammeter. In equations, electric current is often referred to as I, which is used to stand for the intensity of current before the term was shortened to electric current.

Lightning is a form of electric current.
Lightning is a form of electric current.

Electric current can cause fire. When it comes in the form of lightning, this force can set fire to foliage and damage buildings. To prevent lightning damage to buildings in areas prone to lightning storms, building owners often install devices called lightning rods that attract the lightning charge to a high metal rod, which redirects and dispels the current underground. Desert electrical storms that produce lightning with no rain can set fire to dry brush that can grow to damage many homes and acres of land.

Voltage measures the energy that is carried by an electric charge. Voltage is measured in volts. The flow of electricity is often compared to the flow of water, and voltage is the electric equivalent of water pressure. The higher the voltage, the faster electrons will flow through the conductor.

Source / Courtesy : WiseGeek

What is Ohm’s Law?

German physicist Georg Ohm uncovered how a material's make up, length and thickness influences how much current will flow through it at a certain voltage.
German physicist Georg Ohm uncovered how a material’s make up, length and thickness influences how much current will flow through it at a certain voltage.

Ohm’s Law is a law used in physics that basically explains how electricity operates properly within a simple circuit. In order to explain the electrical process, the law shows how the three elements of electricity — ampere, resistance, and voltage — work together to create a functioning electrical circuit. The law states that the amount of electrical current, measured in amperes, traveling through a conductor is proportional or equal to the voltage, but is inversely proportional to the resistance in the conductor.

The proponent and the namesake of the law was George Simon Ohm, a renowned German physicist in the early 1800s. While working as a professor at the Jesuit Gymnasium of Cologne in Germany, he experimented with and observed the behavior of electricity in simple circuits with different wire lengths. He described and documented all the results in a book, “The Galvanic Circuit Investigated Mathematically,” which was initially rejected but later acknowledged, leading to the establishment of the Ohm’s Law.

Ohm’s Law can be written in a simple mathematical equation: I = V/R, where I is for the electrical current measured in amperes, V is for the voltage, and R is for the resistance. In this equation, the resistance is usually a constant variable, since its value is not dependent on the amount of electric current, but rather on the materials used to make the circuit, such as the metal wires and the resistor itself. The formula can be expressed in other inversed forms such as V = IR, or R = V/I. These inversed formulas can help find the value of one element if the values of the two other elements are already identified.

There are essentially three “truth” statements that one should remember regarding Ohm’s Law. The first statement is that the value of I will increase or decrease if the value of V increases or decreases, respectively. The second statement is that the value of I will decrease if the value of R increases and the value of V does not change. The third statement is that the value of I will increase if the value of R decreases and the value of V remains the same.

Ohm's Law can be used to find the electrical resistance applied to a circuit by resistors.
Ohm’s Law can be used to find the electrical resistance applied to a circuit by resistors.

 

The principle of Ohm’s Law can be practically applied in appliances and any equipment operated by electricity or a battery. For example, a simple light-emitting diode (LED) needs only 2 volts and .02 amperes to light up, but is connected to a 6-volt battery. This may cause the LED to short circuit, and a resistor is needed to reduce the current. Using the formula R = V/I, one can determine that a resistor containing 200 ohms is needed to control the current coming into the LED.

 

Source / Courtesy : WiseGeek

Functioning brain tissue grown in 3-D structure

[dropcap]R[/dropcap]esearchers at the RIKEN Center for Developmental Biology in Japan have succeeded in inducing human embryonic stem cells to self-organize into a three-dimensional structure similar to the cerebellum, providing tantalizing clues in the quest to recreate neural structures in the laboratory. One of the primary goals of stem-cell research is to be able to replace damaged body parts with tissues grown from undifferentiated stem cells. For the nervous system, this is a particular challenge because not only do specific neurons need to be generated, but they must also be coaxed into connecting to each other in very specific ways.

RIKEN researchers have taken up this challenge, and the work published in Cell Reports details how sequentially applying several signaling molecules to three-dimensional cultures of human embryotic stem cells prompts the cells to differentiate into functioning cerebellar neurons that self-organize to form the proper dorsal/ventral patterning and multi-layer structure found in the natural developing cerebellum.

Expanding from their previous studies with mice, the researchers first established that under specific conditions, culturing human embryonic stem cells with fibroblast growth factor 2 (FGF2) leads to neural differentiation particular to the midbrain/hindbrain region — the location of the cerebellum — within three weeks, and the expression of markers for the cerebellar plate neuroepithelium — the part of the developing nervous system specific for the cerebellum — within five. These cells also showed early markers that are specific to developing Purkinje cells, granule cells, or deep cerebellar projection neurons — all types of neurons only found in the cerebellum.

The researchers then looked for mature cerebellar neurons. They found that cells treated with FGF2 expressed late Purkinje-cell markers and developed structures characteristic of those cells. Electrophysiological recordings of these cells after culture for about 15 weeks revealed proper responses to currents and to inhibition of receptors needed for normal cerebellar signaling, indicating that function had developed along with structure. Some FGF2-treated cells also expressed markers for the rhombic lip — the structure from which granule cells develop and migrate, and a marker specific to migrating granule precursors by week seven. Moreover, cells were seen to migrate and extend fibers that bent to form the T-shape characteristic of granule cell parallel fibers.

Where these neurons form and how they locate in relation to each other is critical in the developing brain. Early in cerebellar development, particular cell types come to be distributed unevenly from top to bottom, creating a dorsal-ventral separation. Researchers tested several factors, and found that adding FGF19 around day 14 to the FGF2-treated cells caused several flat oval neuroepithelium to form by day 35, expressing dorsal-specific markers on the outside and ventral-specific markers on the inside. By adding stromal cell-derived factor 1 (SDF1) between days 28-35, they were able to generate a continuous neuroepithelial structure with dorsal-ventral polarity.

SDF1 also induced two other important structural changes. The dorsal region spontaneously developed three layers along the dorsal-ventral axis: the ventricular zone, a Purkinje-cell precursor zone, and a rhombic lip zone. At one end of the neuroepithelium, a region developed that was positive for markers of progenitors of granule and deep cerebellar nuclei projection neurons and negative for Purkinje-cell markers, and whose origins could be traced to the rhombic lip zone of the cerebellar plate.

Lead author Keiko Muguruma says that, “the principles of self-organization that we have demonstrated here are important for the future of developmental biology.” She added that, “attempts to generate the cerebellum from human iPS cells have already met with some success, and these patient-derived cerebellar neurons and tissues will be useful for modeling cerebellar diseases such as spinocerebellar ataxia.”


Story Source:

The above story is based on materials provided by RIKEN. Note: Materials may be edited for content and length.


Journal Reference:

  1. Keiko Muguruma, Ayaka Nishiyama, Hideshi Kawakami, Kouichi Hashimoto, Yoshiki Sasai. Self-organization of polarized cerebellar tissue in 3D culture of human pluripotent stem cells. Cell Reports, 2015 DOI:10.1016/j.celrep.2014.12.051

Entanglement : promises secure & faster computers

[dropcap]U[/dropcap]nlike Bilbo’s magic ring, which entangles human hearts, engineers have created a new micro-ring that entangles individual particles of light, an important first step in a whole host of new technologies.

Entanglement — the instantaneous connection between two particles no matter their distance apart — is one of the most intriguing and promising phenomena in all of physics. Properly harnessed, entangled photons could revolutionize computing, communications, and cyber security. Though readily created in the lab and by comparatively large-scale optoelectronic components, a practical source of entangled photons that can fit onto an ordinary computer chip has been elusive.

New research, reported today in The Optical Society’s (OSA) new high-impact journal Optica, describes how a team of scientists has developed, for the first time, a microscopic component that is small enough to fit onto a standard silicon chip that can generate a continuous supply of entangled photons.

The new design is based on an established silicon technology known as a micro-ring resonator. These resonators are actually loops that are etched onto silicon wafers that can corral and then reemit particles of light. By tailoring the design of this resonator, the researchers created a novel source of entangled photons that is incredibly small and highly efficient, making it an ideal on-chip component.

“The main advantage of our new source is that it is at the same time small, bright, and silicon based,” said Daniele Bajoni, a researcher at the Università degli Studi di Pavia in Italy and co-author on the paper. “The diameter of the ring resonator is a mere 20 microns, which is about one-tenth of the width of a human hair. Previous sources were hundreds of times larger than the one we developed.”

From Entanglement to Innovation

Scientists and engineers have long recognized the enormous practical potential of entangled photons. This curious manifestation of quantum physics, which Einstein referred to as “spooky action at a distance,” has two important implications in real-world technology.

First, if something acts on one of the entangled photons then the other one will respond to that action instantly, even if it is on the opposite side of a computer chip or even the opposite side of the Galaxy. This behavior could be harnessed to increase the power and speed of computations. The second implication is that the two photons can be considered to be, in some sense, a single entity, which would allow for new communication protocols that are immune to spying.

This seemingly impossible behavior is essential, therefore, for the development of certain next-generation technologies, such as computers that are vastly more powerful than even today’s most advanced supercomputers, and secure telecommunications.

Creating Entanglement on a Chip

To bring these new technologies to fruition, however, requires a new class of entangled photon emitters: ones that can be readily incorporated into existing silicon chip technologies. Achieving this goal has been very challenging.

To date, entangled photon emitters — which are principally made from specially designed crystals — could be scaled down to only a few millimeters in size, which is still many orders of magnitude too large for on-chip applications. In addition, these emitters require a great deal of power, which is a valuable commodity in telecommunications and computing.

To overcome these challenges, the researchers explored the potential of ring resonators as a new source for entangled photons. These well-established optoelectronic components can be easily etched onto a silicon wafer in the same manner that other components on semiconductor chips are fashioned. To “pump,” or power, the resonator, a laser beam is directed along an optical fiber to the input side of the sample, and then coupled to the resonator where the photons race around the ring. This creates an ideal environment for the photons to mingle and become entangled.

As photons exited the resonator, the researchers were able to observe that a remarkably high percentage of them exhibited the telltale characteristics of entanglement.

“Our device is capable of emitting light with striking quantum mechanical properties never observed in an integrated source,” said Bajoni. “The rate at which the entangled photons are generated is unprecedented for a silicon integrated source, and comparable with that available from bulk crystals that must be pumped by very strong lasers.”

Applications and Future Technology

The researchers believe their work is particularly relevant because it demonstrates, for the first time, a quintessential quantum effect, entanglement, in a well-established technology.

“In the last few years, silicon integrated devices have been developed to filter and route light, mainly for telecommunication applications,” observed Bajoni. “Our micro-ring resonators can be readily used alongside these devices, moving us toward the ability to fully harness entanglement on a chip.” As a result, this research could facilitate the adoption of quantum information technologies, particularly quantum cryptography protocols, which would ensure secure communications in ways that classical cryptography protocols cannot.

According to Bajoni and his colleagues, these protocols have already been demonstrated and tested. What has been missing was a cheap, small, and reliable source of entangled photons capable of propagation in fiber networks, a problem that is apparently solved by their innovation.


Story Source:

The above story is based on materials provided by The Optical Society. Note: Materials may be edited for content and length.


Journal Reference:

  1. Davide Grassani, Stefano Azzini, Marco Liscidini, Matteo Galli, Michael J. Strain, Marc Sorel, J. E. Sipe, Daniele Bajoni. Micrometer-scale integrated silicon source of time-energy entangled photons. Optica, 2015; 2 (2): 88 DOI:10.1364/OPTICA.2.000088