Selasa, 06 Desember 2011

A 3-D Printer Makes Human Bones


We’re already printing organs to order, so why not Cmd+P some customized 3-D bone? Washington State University researchers have tweaked a 3-D rapid prototyper designed to create metal parts to print in a bone-like material that acts as a scaffold for new bone cells. In just a few years, the researchers say, doctors and dentists could be printing up custom bone tissue to order.

Reported in the journal Dental Materials, the bone-like material appears to cause no negative side effects and eventually dissolves. But before doing so, it serves as a scaffold for new bone cells. Placed in a medium of immature human bone cells, the printed structures encourage the growth of new bone that fuses with existing bone tissue.

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"If a doctor has a CT scan of a defect, we can convert it to a CAD file and make the scaffold according to the defect,” Susmita Bose, co-author and professor in WSU’s School of Mechanical and Materials Engineering, said in a press release.


In terms of potential for regenerative medicine, that’s fairly huge. It opens the door to the ability to create perfect--or nearly perfect--replacement implants for damaged or deformed bone tissue and grow new, corrective bone that is the real thing rather than a ceramic or metal analog. And the procedure is relatively fast. Networks of new bone cells reportedly grew within the 3-D printed structures within just a week of placing them in a culture with immature bone cells.

The First Stretchable, Elastic Electrical Cord


Japanese Spandex-maker Asahi Kasei Fibers has developed the world’s first elastic electrical cable, a stretchy conductive connector that could go a long way toward reducing cord clutter. But it’s not just a way to help you manage your multi-cord mess. Called Roboden, the stretchable cord could enable new generations of electronics-embedded textiles and robotic skins.


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Roboden is already available in various kinds of cables, including USB cables and standard power cords, giving you that little bit of extra reach you always need to reach that wall socket. But the real upside is in the realm of automated machinery and robotics. Here, connecting cables previously had to be as long as the machines maximum range of motion to allow the machine to move unrestricted. This meant a lot of loose cord laying around.


With Roboden, the cord stretches when the robot/machine moves and pulls taut when the machine relaxes the tension, keeping extra cord from getting in the way. Likewise, when the day arrives that we want to start sheathing our humanoid robots in soft, skin-like coverings, stretchable electronics and chips are going to be the technologies that get us there.






Senin, 05 Desember 2011

Love, Sex and Brain Development in Adolescence


Teen romance and the possibility of sex...It is one of the trickiest and difficult topics that we, as parents, talk to our kids about. Making sure your teenager has good information and a healthy attitude about opposite sex relationships is a challenging parental responsibility. We know that our teenagers are going to parties, hanging out together, sometimes drinking and some are having sex.
According to a 2005 Statistics Canada report:
o About 12% of teens have had sexual intercourse by age 15 and by the time they reach the age of 17, 28% teens have. By age 24, 80% of young adults have had sexual intercourse.
o Of the sexually active youth between age 15 and 24, over one third of them had more than one partner in a year and 30% did not use a condom the last time they had intercourse.
o Teen pregnancy has been steadily decreasing over the past 25 years. However the number of teens who have contracted sexually transmitted diseases (STDs) such as Chlamydia remains on the rise. This points to reduced use of condoms or the prevalence of oral sex which many teens mistakenly believe eliminates the transmission of STDs.


So, as parents, what sort of influence do we have? According to a 2005 University of Regina in Saskatchewan study, teachers emerged as the most important source for information about pregnancy and STD prevention. The study also found that peer influence was more important than parental disapproval in predicting whether a student would have intercourse. The findings suggest that, teachers and peers are more important in providing good information and instilling attitudes to our teenagers than parents. Parental disapproval has little impact. In fact parental disapproval often has the opposite effect one is trying to accomplish.

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Romance and the Teenage Brain

The conflict between young love and parental disapproval is not a new one. In Shakespeare's Romeo and Juliette, his "star crossed lovers" showed what havoc teen romance can have on families. Today, perhaps it is understandable and acceptable for school to be a more important source of information than parents on certain information about sex. However, most of us hope our values are important to our children and help guide their sexual behaviour choices.
When your son or daughter has fallen in love the personality change may seem extreme. It like they have been invaded by an alien body snatcher. The power of teen love and sex is very strong. Many parents feel responsible for their teenager's risky behavior and become overwhelmed with feelings of guilt. Parents and especially mothers often feel the judgment of other parents whose teen's behaviour is less extreme This can lead to additional feelings of isolation and ineffectiveness. Some parents and especially fathers may get authoritative out of frustration and eventually give up or "wash their hands" of the problem out of feelings of ineptitude.

To be more influential it helps to equipped with the knowledge of what forces are at work when a teenager falls in love. It is important to understand how the teen brain works. Recent brain scientific research sheds much more light on how much hormonal activity is influencing our teenager's thoughts and actions.
Brain structures and brain chemicals both affect the way an adolescent first dives into romance. In his book Why Do They Act That Way?: A Survival Guide to the Adolescent Brain for You and Your Teen, David Walsh describes it this way. At around age ten, the body produces androgen hormones. This is when the first crush can occur. It is at puberty when the real awakening of sexual interest and sex drive occurs. This is when "falling in love" can happen. The hypothalamus drives surges of testosterone in both boys and girls and raises the levels of dopamine - the hormone that is responsible for feelings of pleasure. Because of developmental differences, boys and girls have different attitudes toward sex and romance. The testosterone surges in boys lead them to see girls as sexual objects. Adolescent girls tend to be more drawn to boys for the relational aspects of spending time together and talking.

Although sexual interest is always part of falling in love, falling in love is not always part of sex drive. The prefrontal cortex (the place of reason and judgment in the brain) is inactive and in teenagers not yet fully developed. When falling in love, we aren't using our rational brain and impulse control. A "pleasure" high comes from the hormonal interplay of dopamine, norepinephrine, and serotonin. It is a powerful mix of natural neurological "chemistry". All this high level of hormonal fireworks cannot be sustained for a long time by the brain. The intense feelings of "falling in love" are even shorter for teenagers than adults. Infatuation lasts only about three months on average. Following this they will move on to another relationship for the intoxication and excitement or will stay as the relationship transitions into a calmer more comfortable stable state, which has been called "standing in love".

During the "standing in love" phase cooling down occurs and the prefrontal cortex engages. The teen is in a better position to assess the suitability of the relationship. The adolescent may wonder, "Why am I in this relationship?" A different set of hormones are released now. For girls it is oxytocin sometimes referred to as the "cuddling" hormone, also involved at childbirth, which promotes attachment. In boys, the hormone vasopressin makes them more protective, faithful and attentive to their partner's needs.

 Romantic Pitfalls Often parents worry about their child falling in love with a "bad apple". Concern about a teenager's judgment is warranted. The prefrontal cortex is not completing formed in the brain until age 21. In this stupor of love, the bad influence of the boyfriend or girlfriend leads the "good" child to do things quite out of character. For example they may engage in some risky behavior out of loyalty and love such as destroy property for the "rush" of it.



Sometimes the darker side of love of jealousy and possessiveness takes hold. It is confusing for many teenagers. After the glorious "falling in love" feelings and then attachment hormones can cloud the judgement. He can become controlling, or physically or sexually abusive. When the "why am I in this relationship? question comes to mind, her memories of the "falling in love" times and the current cuddling hormone and lack of experience make it more difficult to see the wisdom of getting out.

Tips for Talking to Teens about Sex Countries with low rates of teen pregnancy and STDs deal with sex more openly. If trusted adults, teachers and parents don't talk openly, the adolescents will get their information from peers or the media. It is important to distinguish sex from sexuality. Sex is about biology whereas sexuality is about biology, psychology, values and spirituality. It is important for you to see your role as supplementing the logic, wisdom and judgement that the teen's under developed prefrontal cortex requires. Actively listening, validating feelings and show respect will help open up discussions and reduce power struggles.
David Walsh in his book Why Do They Act That Way?, suggests the following tips and do's and don'ts.

1. Get motivated. If you do not talk to them someone else will.
2. Get educated. Being informed overcomes nervousness and builds confidence
3. Get comfortable. It is ok to admit some discomfort. It will help everyone relax.
4. Make it an ongoing conversation.
5. Don't try to cover too much in one discussion.
6. Choose appropriate times when there is an opportunity for calm, private uninterrupted conversation
7. Discuss sexuality, not just sex. They need to know about the place of sex in a healthy relationship.
8. Discuss dating as a time to have fun and get to know each other.
9. Don't preach or lecture.
10. Make it a dialogue
11. Share your values

Do
o Emphasize the importance of respect and honesty in all relationships
o Have regular conversations with your sons and daughters about sex and sexuality
o Communicate the values you consider important in romantic relationships
o Provide accurate information about birth control and STDs
o Get to know your adolescent's friends so you know who they are influenced by
o Really listen to your teen: their fears, and worries and validate their feelings showing acceptance and love
o Talk to other parents, join a parents group, see a counselor for ideas and support

Don't
o Don't get angry or use put-downs about a boyfriend or girlfriend you have concerns about
o Don't ridicule or make fun of crushes or romantic attachments
o Don't assume that your son or daughter won't engage in sexual behavior
o Don't keep quiet and let the "instant sex" that happens on TV and in movies become the only examples your kids have about sex and sexuality Allan Findlay M.S.W. is a Toronto based Marriage and Family Therapist. He is a Registered Clinical Social Worker with extensive experience helping couples and families for over 25 years restore respect and rebuild trust.

For couples in crisis in the aftermath of an extra-marital affair, or for those who are drifting apart, couples benefit from Allan's structured counseling approach. His therapy de-escalates negative interactions and establishes new patterns that promote secure emotional attachments in adult relationships. Trust is rebuilt, problems solved, partnership strengthened, and intimacy restored.
For parents whose teenagers are uncommunicative, disrespectful, defiant, or are abusing drugs or alcohol, families come to Allan before it is necessary to kick their teen out of home. His extensive knowledge of the psychological development of teenagers, his gentle but firm style and structured approach de-escalates conflict and restores respectful relationships between all family members.
Environment Clean Generations

Can we Predict When and Where Quakes will Strike?


This week, six seismologists go on trial for the manslaughter of 309 people, who died as a result of the 2009 earthquake in l'Aquila, Italy.
The prosecution holds that the scientists should have advised the population of l'Aquila of the impending earthquake risk.
But is it possible to pinpoint the time and location of an earthquake with enough accuracy to guide an effective evacuation?
There are continuing calls for seismologists to predict where and when a large earthquake will occur, to allow complete evacuation of threatened areas.

Predicting an earthquake with this level of precision is extremely difficult, because of the variation in geology and other factors that are unique to each location.
Attempts have been made, however, to look for signals that indicate a large earthquake is about to happen, with variable success.

Historically, animals have been thought to be able to sense impending earthquakes.
Noticeably erratic behaviour of pets, and mass movement of wild animals like rats, snakes and toads have been observed prior to several large earthquakes in the past.
Following the l'Aquila quake, researchers published a study in the Journal of Zoology documenting the unusual movement of toads away from their breeding colony.

But scientists have been unable to use this anecdotal evidence to predict events.
The behaviour of animals is affected by too many factors, including hunger, territory and weather, and so their erratic movements can only be attributed to earthquakes in hindsight.


What causes an earthquake?

An earthquake is caused when rocks in the Earth's crust fracture suddenly, releasing energy in the form of shaking and rolling, radiating out from the epicentre.
The rocks are put under stress mostly by friction during the slow, 1-10 cm per year shuffling of tectonic plates.
The release of this friction can happen at any time, either through small frequent fractures, or rarer breaks that release a lot more energy, causing larger earthquakes.
It is these large earthquakes that have devastating consequences when they strike in heavily populated areas.
Attempts to limit the destruction of buildings and the loss of life mostly focus on preventative measures and well-communicated emergency plans.

Precursor events
 
When a large amount of stress is built up in the Earth's crust, it will mostly be released in a single large earthquake, but some smaller-scale cracking in the build-up to the break will result in precursor earthquakes.

"There is no scientific basis for making a prediction”
Richard Walker University of Oxford
 
These small quakes precede around half of all large earthquakes, and can continue for days to months before the big break.
Some scientists have even gone so far as to try to predict the location of the large earthquake by mapping the small tremors.
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The "Mogi Doughnut Hypothesis" suggests that a circular pattern of small precursor quakes will precede a large earthquake emanating from the centre of that circle.
While half of the large earthquakes have precursor tremors, only around 5% of small earthquakes are associated with a large quake.
So even if small tremors are felt, this cannot be a reliable prediction that a large, devastating earthquake will follow.
"There is no scientific basis for making a prediction", said Dr Richard Walker of the University of Oxford.
In several cases, increased levels of radon gas have been observed in association with rock cracking that causes earthquakes.

Radon is a natural and relatively harmless gas in the Earth's crust that is released to dissolve into groundwater when the rock breaks.
Similarly, when rock cracks, it can create new spaces in the crust, into which groundwater can flow.
Measurements of groundwater levels around earthquake-prone areas see sudden changes in the level of the water table as a result of this invisible cracking.
Unfortunately for earthquake prediction, both the radon emissions and water level changes can occur before, during, or after an earthquake, or not at all, depending on the particular stresses a rock is put under.

Advance warning systems
 
The minute changes in the movement, tilt, and the water, gas and chemical content of the ground associated with earthquake activity can be monitored on a long term scale.
Measuring devices have been integrated into early warning systems that can trigger an alarm when a certain amount of activity is recorded.

"Prediction will only become possible with a detailed knowledge of the earthquake process. Even then, it may still be impossible”
Dr. Dan Faulkner University of Liverpool


Such early warning systems have been installed in Japan, Mexico and Taiwan, where the population density and high earthquake risk pose a huge threat to people's lives.
But because of the nature of all of these precursor reactions, the systems may only be able to provide up to 30 seconds' advance warning.

"In the history of earthquake study, only one prediction has been successful", explains Dr Walker.
The magnitude 7.3 earthquake in 1975 in Haicheng, North China was predicted one day before it struck, allowing authorities to order evacuation of the city, saving many lives.
But the pattern of seismic activity that this prediction was based on has not resulted in a large earthquake since, and just a year later in 1976 a completely unanticipated magnitude 7.8 earthquake struck nearby Tangshan causing the death of over a quarter of a million people.
The "prediction" of the Haicheng quake was therefore just a lucky unrepeatable coincidence.
A major problem in the prediction of earthquake events that will require evacuation is the threat of issuing false alarms.
Scientists could warn of a large earthquake every time a potential precursor event is observed, however this would result in huge numbers of false alarms which put a strain on public resources and might ultimately reduce the public's trust in scientists.

"Earthquakes are complex natural processes with thousands of interacting factors, which makes accurate prediction of them virtually impossible," said Dr Walker.
Seismologists agree that the best way to limit the damage and loss of life resulting from a large earthquake is to predict and manage the longer-term risks in an earthquake-prone area. These include the likelihood of building collapsing and implementing emergency plans.

"Detailed scientific research has told us that each earthquake displays almost unique characteristics, preceded by foreshocks or small tremors, whereas others occur without warning. There simply are no rules to utilise in order to predict earthquakes," said Dr Dan Faulkner, senior lecturer in rock mechanics at the University of Liverpool.
"Earthquake prediction will only become possible with a detailed knowledge of the earthquake process. Even then, it may still be impossible."

A Higgs Boson Announcement be Imminent from the LHC?


Physicists at the Large Hadron Collider could be getting an early Christmas present: the Higgs boson. According to the latest rumours, scientists at the LHC are seeing a signal that could correspond to a Higgs particle with a mass of 125 GeV (a proton is slightly less than 1 GeV).
Public talks are scheduled to discuss the latest results from Atlas and CMS, two of the main LHC experiments, on 13 December. This follows one day after a closed-door Cern council meeting where officials will get a short preview of the findings, whatever they may be.


"Chances are high (but not strictly 100%) that the talks will either announce a (de facto or de iure) discovery or some far-reaching exclusion that will be really qualitative and unexpected," wrote theoretical physicist Lubos Motl on his blog.
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...........................................................................................................................................................Motl also mentioned that an internal email sent to the Cern community suggests that results on the elusive Higgs -- which is required under the Standard Model of particle physics to provide mass to different particles -- will be inconclusive. This could mean that the finding is below the five-sigma threshold needed to definitively declare a discovery in physics.

But if the rumours are true, and the Higgs has been seen at 125 GeV, it could bolster the idea that there is physics beyond the Standard Model that describes the behaviour of subatomic particles. A 125 GeV Higgs is lighter than predicted under the simplest models and would likely require more complex theories, such as supersymmetry, which posits the existence of a heavier partner to all known particles.

Kobo Vox E-book Reader


Why do you want an e-book reader? It sounds like a trick question, but your answer is vital. If you said "to read books" look no further than traditional monochrome e-ink readers such as the Amazon Kindle. If you said "to read books and…" the Kobo Vox is aimed at you.
Designed to go head-to-head with Amazon's much-hyped Kindle Fire, the Kobo Vox is part of a new wave of e-book readers aimed at people who find reading isn't enough. Consequently these devices are hybrids that keep e-books and e-book purchasing at their core, but add aspects of tablet functionality such as app stores and multimedia playback while keeping the price low. On paper this sounds like the best of both worlds. The trouble is we're not dealing with paper anymore.

 Design
This material difference becomes apparent before the Vox is switched on. At 192.2 x 129.5mm the Vox has a conveniently small footprint, but at 13.4mm deep it is almost twice as thick as both a standard Kindle (fourth generation) and the iPad 2. At 400g it is also more than twice the weight of the Kindle, two thirds the weight of an iPad 2 and actually heavier than Samsung's 345g Galaxy Tab 7.0 Plus Android tablet.


In all fairness to Kobo, the Vox is essentially a stripped down tablet and it runs Android 2.3 "Gingerbread" so these figures shouldn't be surprising. What does surprise is how disappointing the Vox is in hand, with lacklustre build materials and poor-feeling construction. The exterior of the Vox is a mess of unflattering plastics. The facia is reflective piano black, the screen itself is plastic not glass and lacks an oil-resistant layer to ward off fingerprints. The sides switch to a matt black finish with a plastic power button and volume rocker -- both painted silver to look like metal -- while the rear changes again to a rubber textured diamond pattern. Superficially the pattern itself is pleasant on the eyes but much as the facia picks up every fingerprint, the rear shows off every bump, scuff or scratch which doesn't bode well for its long term durability.

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Poor screen, poor performance

Unfortunately this is just the tip of the iceberg. Switch on the Vox and you'll quickly notice the 7-inch screen is second rate. Seven inches is quickly becoming the norm for this new breed of e-book reader as is its 1024 x 600 resolution, but Kobo has broken from the pack in choosing an FFS+ display instead of IPS. This gamble fails. Colours look washed out, but worse still text is notably pixelated making it unpleasant to read over longer periods. For years smartphones may have gotten away with substandard call quality in lieu of additional functionality, but we can't see how an e-book reader can similarly survive being so poor at its primary purpose.


The iceberg gets bigger still. In opting for so much plastic Kobo has committed a cardinal sin: not using a glass screen. The company insists the Vox uses a capacitive layer, but response times are as poor as an old resistive touchscreen and multiple touches are commonly required to get it to recognise commands. That said we can't lay all the blame squarely on the screen because the hardware is equally culpable.

THe Fleet of British Radar Satellites


An ambitious project to put a fleet of British radar satellites into orbit around the Earth has been funded with money from the Chancellor's autumn statement.
The project is part of a £200 million boost for the scientific sector, and the government's funding will be matched by industry. The goal is to allow any location on Earth to be imaged within 24 hours. Radar is a particularly potent tool for this, as it can penetrate cloud cover.
The spacecraft that'll host the radars are called NovaSar-S, with "Sar" standing for "synthetic aperture radar". They weigh 400kg and measure three metres long by one metre wide, giving them a long, thin profile.



What's particularly impressive is the price tag -- by condensing the equipment into a much smaller body, the cost of each spacecraft is dramatically lowered -- down to about £45m, launched and insured. That's a fraction of what's charged for larger radar satellites.
The instruments on board could provide a wide range of functions, including flood monitoring, land cover management, disaster mapping, oil spill detection and ship tracking. It's hoped that it'll be particularly useful in monitoring deforestation in tropical areas, where persistent cloud cover often makes it difficult to get data.

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Martin Sweeting, the executive chairman of the company behind the satellite, Surrey Satellite Technology Limited (SSTL), told BBC News: "We're hoping we can use this commitment from the UK government to go out to our international customers, who we know have had an interest in radar for a long time, and get them to participate in the first mission, to start with, but then to take up one or two of the other satellites so that we can build a constellation in orbit."