Electron Microscope Video Of A Needle On A Vinyl Record.

Chaotic behaviour in 50-link pendulum.

Galaxies: Types and morphology

A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. Galaxies range in size from dwarfs with just a few hundred million (108) stars to giants with one hundred trillion (1014) stars, each orbiting its galaxy’s center of mass.

Galaxies come in three main types: ellipticals, spirals, and irregulars. A slightly more extensive description of galaxy types based on their appearance is given by the Hubble sequence. 

Since the Hubble sequence is entirely based upon visual morphological type (shape), it may miss certain important characteristics of galaxies such as star formation rate in starburst galaxies and activity in the cores of active galaxies.

Ellipticals

The Hubble classification system rates elliptical galaxies on the basis of their ellipticity, ranging from E0, being nearly spherical, up to E7, which is highly elongated. These galaxies have an ellipsoidal profile, giving them an elliptical appearance regardless of the viewing angle. Their appearance shows little structure and they typically have relatively little interstellar matter. Consequently, these galaxies also have a low portion of open clusters and a reduced rate of new star formation. Instead they are dominated by generally older, more evolved stars that are orbiting the common center of gravity in random directions.

Spirals

Spiral galaxies resemble spiraling pinwheels. Though the stars and other visible material contained in such a galaxy lie mostly on a plane, the majority of mass in spiral galaxies exists in a roughly spherical halo of dark matter that extends beyond the visible component, as demonstrated by the universal rotation curve concept.

Spiral galaxies consist of a rotating disk of stars and interstellar medium, along with a central bulge of generally older stars. Extending outward from the bulge are relatively bright arms. In the Hubble classification scheme, spiral galaxies are listed as type S, followed by a letter (a, b, or c) that indicates the degree of tightness of the spiral arms and the size of the central bulge.

Barred spiral galaxy

A majority of spiral galaxies, including our own Milky Way galaxy, have a linear, bar-shaped band of stars that extends outward to either side of the core, then merges into the spiral arm structure. In the Hubble classification scheme, these are designated by an SB, followed by a lower-case letter (a, b or c) that indicates the form of the spiral arms (in the same manner as the categorization of normal spiral galaxies). 

Ring galaxy

A ring galaxy is a galaxy with a circle-like appearance. Hoag’s Object, discovered by Art Hoag in 1950, is an example of a ring galaxy. The ring contains many massive, relatively young blue stars, which are extremely bright. The central region contains relatively little luminous matter. Some astronomers believe that ring galaxies are formed when a smaller galaxy passes through the center of a larger galaxy. Because most of a galaxy consists of empty space, this “collision” rarely results in any actual collisions between stars.

Lenticular galaxy

A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. They contain large-scale discs but they do not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks.

Irregular galaxy

An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.

Dwarf galaxy

Despite the prominence of large elliptical and spiral galaxies, most galaxies in the Universe are dwarf galaxies. These galaxies are relatively small when compared with other galactic formations, being about one hundredth the size of the Milky Way, containing only a few billion stars. Ultra-compact dwarf galaxies have recently been discovered that are only 100 parsecs across.

Interacting

Interactions between galaxies are relatively frequent, and they can play an important role in galactic evolution. Near misses between galaxies result in warping distortions due to tidal interactions, and may cause some exchange of gas and dust. Collisions occur when two galaxies pass directly through each other and have sufficient relative momentum not to merge.

Starburst

Stars are created within galaxies from a reserve of cold gas that forms into giant molecular clouds. Some galaxies have been observed to form stars at an exceptional rate, which is known as a starburst. If they continue to do so, then they would consume their reserve of gas in a time span less than the lifespan of the galaxy. Hence starburst activity usually lasts for only about ten million years, a relatively brief period in the history of a galaxy.

Active galaxy

A portion of the observable galaxies are classified as active galaxies if the galaxy contains an active galactic nucleus (AGN). A significant portion of the total energy output from the galaxy is emitted by the active galactic nucleus, instead of the stars, dust and interstellar medium of the galaxy.

The standard model for an active galactic nucleus is based upon an accretion disc that forms around a supermassive black hole (SMBH) at the core region of the galaxy. The radiation from an active galactic nucleus results from the gravitational energy of matter as it falls toward the black hole from the disc. In about 10% of these galaxies, a diametrically opposed pair of energetic jets ejects particles from the galaxy core at velocities close to the speed of light. The mechanism for producing these jets is not well understood.

The main known types are: Seyfert galaxies, quasars, Blazars, LINERS and Radio galaxy.

source

images: NASA/ESA, Hubble (via wikipedia)

A neural network invents diseases you don’t want to get

Science fiction writers and producers of TV medical dramas: have you ever needed to invent a serious-sounding disease whose symptoms, progression, and cure you can utterly control? Artificial intelligence can help!

Blog reader Kate very kindly compiled a list of 3,765 common names for conditions from this site, and I gave them to an open-source machine learning algorithm called a recursive neural network, which learns to imitate its training data. Given enough examples of real-world diseases, a neural network should be able to invent enough plausible-sounding syndromes to satisfy any hypochondriac.

Early on in the training, the neural network was producing what were identifiably diseases, but probably wouldn’t fly in a medical drama. “I’m so sorry. You have… poison poison tishues.”

Much Esophageal Eneetems Vomania Poisonicteria Disease Eleumathromass Sexurasoma Ear Allergic Antibody Insect Sculs Poison Poison Tishues Complex Disease

As the training got going, the neural network began to learn to replicate more of the real diseases - lots of ventricular syndromes, for example. But the made-up diseases still weren’t too convincing, and maybe even didn’t sound like diseases at all. (Except for RIP Syndrome. I’d take that one seriously)

Seal Breath Tossy Blanter Cancer of Cancer Bull Cancer Spisease Lentford Foot Machosaver RIP Syndrome

The neural network eventually progressed to a stage where it was producing diseases of a few basic varieties :

First kind of disease: This isn’t really a disease. The neural network has just kind of named a body part, or a couple of really generic disease-y words. Pro writer tip: don’t use these in your medical drama.

Fevers Heading Disorder Rashimia Causes Wound Eye Cysts of the Biles Swollen Inflammation Ear Strained Lesions  Sleepys Lower Right Abdomen  Degeneration Disease Cancer of the Diabetes

Second kind of disease: This disease doesn’t exist, and sounds reasonably convincing to me, though it would probably have a different effect on someone with actual medical training.

Esophagia Pancreation  Vertical Hemoglobin Fever  Facial Agoricosis Verticular Pasocapheration Syndrome Agpentive Colon  Strecting Dissection of the Breath  Bacterial Fradular Syndrome Milk Tomosis Lemopherapathy  Osteomaroxism Lower Veminary Hypertension Deficiency Palencervictivitis Asthodepic Fever Hurtical Electrochondropathy  Loss Of Consufficiency Parpoxitis Metatoglasty Fumple Chronosis Omblex's  Hemopheritis  Mardial Denection Pemphadema Joint Pseudomalabia Gumpetic Surpical Escesion Pholocromagea  Helritis and Flatelet’s Ear Asteophyterediomentricular Aneurysm 

Third kind of disease: Sounds both highly implausible but also pretty darn serious. I’d definitely get that looked at.

Ear Poop  Orgly Disease Cussitis Occult Finger Fallblading Ankle Bladders Fungle Pain Cold Gloating Twengies Loon Eye Catdullitis Black Bote Headache Excessive Woot Sweating Teenagerna Vain Syndrome  Defentious Disorders Punglnormning Cell Conduction Hammon Expressive Foot Liver Bits Clob Sweating,Sweating,Excessive  Balloblammus  Metal Ringworm  Eye Stools Hoot Injury  Hoin and Sponster Teenager’s Diarey  Eat Cancer Cancer of the Cancer Horse Stools Cold Glock Allergy Herpangitis Flautomen Teenagees Testicle Behavior  Spleen Sink Eye Stots Floot Assection Wamble Submoration  Super Syndrome Low Life Fish Poisoning Stumm Complication Cat Heat Ovarian Pancreas 8 Poop Cancer Of Hydrogen Bingplarin Disease Stress Firgers Causes of the ladder Exposure Hop D Treat Decease

Diseases of the fourth kind: These are the, um, reproductive-related diseases. And those that contain unprintable four-letter words. They usually sound ludicrous, and entirely uncomfortable, all at the same time. And I really don’t want to print them here. However! If you are in possession of a sense of humor and an email address, you can let me know here and I’ll send them to you.

Neuroscientist Discovers Potential New Source for Pain Inhibition

A UT Dallas scientist has found a new neurological mechanism that appears to contribute to a reduction in pain.

According to Dr. Ted Price, associate professor in the School of Behavioral and Brain Sciences, the discovery of neuroligin-2 as a cause exacerbating chronic pain is significant for the research community. Although the findings likely won’t immediately lead to new pain therapies, the findings offer a potential new therapeutic direction to investigate, he said.

Price’s research on the topic has recently been published online in Pain, the journal of the International Association for the Study of Pain.

The study focused on the body’s inhibitory networks — a series of biochemical reactions that decrease certain neurological activity, such as pain. Price said a great deal of previous research in this area has focused on the activity of the neurotransmitter GABA, a chemical released by nerve cells in the brain.

Normally, a GABA neurotransmitter acts to inhibit neuronal activity, such as pain. However, when pain becomes chronic there is strong evidence that a process called GABAergic plasticity can cause GABA to lose its inhibitory activity, sometimes making the pain even worse.

The source of these excitatory actions in neuronal circuits has been broadly attributed to chloride ions, but Price’s research has found another potential cause of GABAergic plasticity: synaptic adhesion molecules called neuroligin-2.

“From a basic science perspective, we’re really excited about it because it demonstrates that the types of GABAergic plasticity that can occur in the setting of chronic pain are more diverse than we’ve appreciated before,” he said.

Price, who heads the undergraduate research program in neuroscience in the school, focuses much of his research on understanding the neuroscience behind pain, particularly chronic pain. He said individuals with chronic pain typically don’t receive the pain-reduction benefits delivered by inhibitory systems. Instead, they often experience increased pain.

“When you hit your hand with a hammer, almost everybody has the same reflex reaction — that is, to rub your finger which, in turn, helps to reduce pain. The reason that works is because it increases GABAergic inhibition in the spinal cord,” Price said. “However, people who have chronic pain — if they do the same thing — find that rubbing it actually makes the pain worse. That’s because the GABAergic system loses its efficacy and, in fact, can become excitatory.”

Price said the research is another step in determining why the GABAergic system stops working correctly in some people and provides a second theory for what drives the system.

“Having two ideas and different models will allow us to determine what the therapeutic opportunities are — creating something that will change that back to normal. The lack of performance in the inhibitory system is very detrimental to those who are in chronic pain,” he said.

Price said the development of chronic pain is, in essence, one’s body “learning” something that is bad.

“It’s changing the way the body functions — it’s learning. That learning, in the case of chronic pain, is aberrant — it’s causing the situation to get worse. If we can figure out what that form of learning was, then we can potentially reverse it. Understanding that the GABAergic system changes during this form of learning potentially offers a new therapeutic avenue,” he said.

fMRI differences in brain activity in prefrontal cortex.

My tummy is blushing now. 

People Were Asked: ‘What’s The Coolest Thing Most People Don’t Know About Their Own Body?’

Absence of Serotonin Alters Development and Function of Brain Circuits

Researchers at Case Western Reserve University School of Medicine have created the first complete model to describe the role that serotonin plays in brain development and structure. Serotonin, also called 5-hydroxytryptamine [5-HT], is an important neuromodulator of brain development and the structure and function of neuronal (nerve cell) circuits. The results were published in the current issue of The Journal of Neurophysiology online.

“Our goal in the project was to close the gap in knowledge that exists on role of serotonin in the brain cortex, particularly as it concerns brain circuitry, its electrical activity and function,” said Roberto Fernández Galán, PhD, Assistant Professor in the Department of Neurosciences at Case Western Reserve University School of Medicine. “For the first time, we can provide a complete description of an animal model from genes to behavior—including at the level of neuronal network activity, which has been ignored in most studies to date.”

Dr. Galán and his team used high-density multi-electrode arrays in a mouse model of serotonin deficiency to record and analyze neuronal activity. The study supports the importance of the serotonin which is specified and maintained by a specific gene, the Pet-1 gene – for normal functioning of the neurons, synapses and networks in the cortex, as well as proper development of brain circuitry. Serotonin abnormalities have been linked to autism and epilepsy, depression and anxiety. By more fully elucidating the role of serotonin in the brain, this study may contribute to a better understanding of the development or treatment of these conditions.

“By looking at the circuit level of the brain, we now have new insight into how the brain becomes wired and sensitive to changing serotonin levels.” added Dr. Galán.

what the article doesn’t tell you is that this has happened once before, and she forgot how to use her drill. she remembered how to drill later one, but then she shut down again for no clear reason. it is still unclear if she remembers how to drill. i love her so much

‘Smart fat cells’ cross blood-brain barrier to catch early brain tumors

An MRI contrast agent that can pass through the blood-brain barrier will allow doctors to detect deadly brain tumors called gliomas earlier, say Penn State College of Medicine researchers. This ability opens the door to make this fatal cancer treatable.

Gliomas are brain tumors that arise from glial cells, which help nerve cells to stay connected and send signals throughout the body.

Cancerous gliomas are uniformly fatal, with a median survival rate of 14 months from the time of diagnosis. But a new nanotechnology approach developed by Xiaoli Liu and Madhan Kumar in the Department of Neurosurgery could transform gliomas from a death sentence into a treatable condition.

Patients diagnosed with a malignant glioma can undergo surgery, chemotherapy and radiation to destroy the tumor, but the cancer will return.

“Patients typically don’t die from the tumor they initially presented with. Rather, they die from new tumors that come back in other parts of the brain,” said James Connor, Distinguished Professor of Neurosurgery.

These new gliomas tend to grow quickly and are often resistant to treatment because they spring from cancer cells that survived the first therapeutic assault. Glioma patients have follow-up MRIs to detect new brain cancers but the tests do not catch the tumors early enough to save lives.

That is because contrast agents used to outline gliomas on an MRI can only pass the protective blood-brain barrier once the tumors have grown large enough to cause damage to the barrier. Until then, the blood-brain barrier blocks 98 percent of small molecules and all large molecules from entering the brain.

To overcome this deadly limitation, Penn State researchers created “smart fat cells” called liposomes that can pass the blood-brain barrier in mice, seek out tiny cancerous gliomas like heat-seeking missiles and light them up on an MRI. The liposomes are loaded with the most commonly used contrast agent, Magnevist. On their surface, the liposomes are studded with proteins that target receptors on glioma cells.

The new contrast agent delivery system is more sensitive than traditional contrast-enhanced MRI, Connor said.

The researchers found that the liposomes entered the brain in healthy mice with uncompromised blood-brain barriers. Both the conventional and the new technique found large gliomas in mice with cancer, but only the liposome-encapsulated agent was able to detect smaller early-stage tumors. “The goal is to be able to get down to detecting single cancer cells,” Connor said.

The study was published in Journal of Neuro-Oncology.

It is not exactly known how the liposomes get past the intact blood-brain barrier, but they apparently do it without causing damage. In the study, mice showed no harm from the treatment.

This novel approach is an alternative to ultrasound, another promising method researchers are studying to get therapeutic agents into the brain. Ultrasound, however,  causes temporary disruption to the blood-brain barrier, which allows not only the therapeutic agent to enter the brain, but also blood which could have medical implications.

“Ultrasound, with all of its good qualities, is disruptive to the blood-brain barrier, whereas we can get an agent to cross it without causing disruption.” Connor said.

The researchers said that in the future, smart fat cells will deliver chemotherapeutic drugs, along with contrast agents, to brain tumor patients so that cancer cells can be detected and wiped out in one step. They recently presented research on these next-generation liposomes at the Society for Neuro-Oncology meeting in San Antonio.

Women scientists made up 25% of the Pluto fly-by New Horizon team. Make sure you share this, because erasing women’s achievements in science and history is a tradition. Happens every day.

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http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20150712