How does a machine verify the identity of a human being? Irises, heartbeats, fingertips and voices, for starters.
Authentication has been a tough nut to crack since the early days of the Web. Now comes a batch of high-tech alternatives, some straight from science fiction, as worries grow about the security risks associated with traditional user name and password systems.
Apple on Tuesday introduced two new iPhones, including for the first time a model with a fingerprint sensor that can be used instead of a passcode to open the phone and buy products. The new feature is part of a trove of authentication tools being developed for consumers, and not just for phones.
Some of these, like the fingerprint sensor, involve the immutable properties humans are encoded with, while others turn our phones into verification devices.
Excerpt from an article written by SOMINI SENGUPTA at NYT. Continue THERE
The familiar trigonometric functions can be geometrically derived from a circle.
But what if, instead of the circle, we used a regular polygon?
In this animation, we see what the “polygonal sine” looks like for the square and the hexagon. The polygon is such that the inscribed circle has radius 1.
We’ll keep using the angle from the x-axis as the function’s input, instead of the distance along the shape’s boundary. (These are only the same value in the case of a unit circle!) This is why the square does not trace a straight diagonal line, as you might expect, but a segment of the tangent function. In other words, the speed of the dot around the polygon is not constant anymore, but the angle the dot makes changes at a constant rate.
Since these polygons are not perfectly symmetrical like the circle, the function will depend on the orientation of the polygon.
A ventricular assist system, or VAD, is a implantable device that is used to help a failing heart pump blood through the body, often while the patient is awaiting a heart transplant. It consists of a control system and an energy supply worn outside the body and a pump implanted by the heart or in the abdominal pouch. VADs are generally used to take blood from the left ventricle or deliver it to the aorta. They may also be used to take blood from the right ventricle and deliver it to the pulmonary artery. The latest VADs use continuous-flow pumps that use electric currents to spin a rotor that accelerates blood through the pump. The rotor uses electromagnetic or hydrodynamic suspension instead of ball-bearing suspension, reducing wear-and-tear on the rotor. Source: American Heart Association, FDA
X-ray showing Dual turbine-like blood pumps replacing explanted heart. On March 10, 2011, Drs. Bud Frazier and Billy Cohn implanted the 2 approved devices manufactured by Thoratec into 55-year-old Houstonian Craig A. Lewis. These devices were used in a last attempt to save his life.
The search for the perfect artificial heart seems never-ending. After decades of trial and error, surgeons remain stymied in their quest for a machine that does not wear out, break down or cause clots and infections.
But Dr. Billy Cohn and Dr. Bud Frazier at the Texas Heart Institute say they have developed a machine that could avoid all that with simple whirling rotors — which means people may soon get a heart that has no beat.
Inside the institute’s animal research laboratory is an 8-month-old calf with a soft brown coat named Abigail. Cohn and Frazier removed Abigail’s heart and replaced it with two centrifugal pumps.
“If you listened to her chest with a stethoscope, you wouldn’t hear a heartbeat,” says Cohn. “If you examined her arteries, there’s no pulse. If you hooked her up to an EKG, she’d be flat-lined.”
The pumps spin Abigail’s blood and move it through her body.
“By every metric we have to analyze patients, she’s not living,” Cohn says. “But here you can see she’s a vigorous, happy, playful calf licking my hand.”
Written by Carrie Feibel, NPR. Continue HERE
Steven Parnis, assistant director of technology development at the Texas Heart Institute, prepares the pair of ventricular assist devices for surgery. These devices use spinning rotors to circulate blood, instead of rhythmic contractions. Courtesy of the Texas Heart Institute