Humans sense 10 basic types of smell, scientists say

When it comes to aromas, the whole may simply be the sum of 10 basic parts

The thousands of aromas humans can smell can be sorted into 10 basic categories, US scientists say.

Prof Jason Castro, of Bates College, and Prof Chakra Chennubhotla, of the University of Pittsburgh, used a computerised technique to whittle down smells to their most basic essence.

They told the PLoS One journal they had then tested 144 of these and found they could be grouped into 10 categories.

The findings are contentious - some say there are thousands of permutations.

The 10 proposed smells

  • Fragrant
  • Woody/resinous
  • Fruity (non-citrus)
  • Chemical
  • Minty/peppermint
  • Sweet
  • Popcorn
  • Lemon
  • Pungent
  • Decayed

Prof Castro said: "You have these 10 basic categories because they reflect important attributes about the world - danger, food and so on.

"If you know these basic categories, then you can start to think about building smells.

"We have not solved the problem of predicting a smell based on its chemical structure, but that's something we hope to do."

He said it would be important to start testing the theory on more complex aromas, such as perfumes and everyday smells.

In reality, any natural scent was likely to be a complex mix - a blend of the 10 different categories, he said.

Prof Tim Jacob, a UK expert in smell science at Cardiff University, said: "In the 1950s a scientist called John Amoore proposed a theory which involved seven smell categories based upon molecular shape and size.

"He eventually withdrew it, to the poorly suppressed glee of his rival R W Moncrieff, who said there was 'never much solid evidence to support it, and there were difficulties all along the line, but it did stimulate a lot of useful thought'.

"I'm sure that Castro et al's paper will 'stimulate a lot of useful thought'."

Source: BBC

N.H.Khider

New Exercises to Triple Your Calorie Burn

Mix up your workout with challenging new moves that burn fat, tone your muscles, and shake up your routine.

Build a better body

Your body is a marvel of efficiency: Do something over and over and, before long, you get so good at it you do it on autopilot. That’s a wonderful thing when it comes to learning a new language, it’s not so great when it comes to your workout.

There’s a simple way to get your body back in fat-blasting mode: Temporarily ditch your go-to moves. "When you change up your workout, your body works harder because it’s in unfamiliar territory," explains Amy Dixon, a Santa Monica, California–based trainer and exercise physiologist. "That’s what causes it to burn more calories and build more muscle."

Use the pro's tips

Do this series two to three times per week, alternating with cardio days; you’ll start to see results in as little as two to three weeks. Each move hits the same major muscle groups as the old standbys, but challenges them more, giving you a stronger, sleeker body in the same amount of time. So it’s efficient—in the best way possible.

Skip squats, do: Bridge drag

Lie on your back with heels and calves on a stability ball, arms by your sides. Press shoulder blades into floor and lift hips so body forms a straight line from shoulders to heels. Tighten core and slowly drag both heels in toward butt, bending knees and keeping body lifted.

Without dropping hips, slowly extend both legs back to previous position. Do 3 sets of 15 reps.

 

Why it’s better: It challenges your core more than a squat does.

Skip lunges, do: Knee-cross curtsy

Stand with feet shoulder-width apart. Lift right leg straight back and up; at same time, hinge at waist and bring hands or fingertips to floor in front of left foot. Bend both knees, bringing right knee behind left knee. Press back up through left foot to return to previous position. Do 15 reps, keeping leg raised, then switch sides and repeat. Do 3 sets.

Why it’s better: It allows for a greater range of motion than a basic lunge (adding flexibility to the mix), plus challenges your balance, strengthening your core. sculpts and defines the same muscles without the impact on your knees.

Skip push-ups, do: Ball fly

Sit on a stability ball with a 5- to 10-lb dumbbell in your right hand. Slowly roll down and back until head and shoulders are on the ball, feet hip-width on floor with knees bent. Brace core, press heels into floor, and raise hips up to bridge position.

Extend right arm toward the ceiling so weight is directly above your shoulder with palm facing in; lift and straighten left leg. Keeping leg raised, slowly lower right arm out to the side until it’s at shoulder level. Use chest muscles to bring right arm back up. Do 15 reps, keeping leg raised, then switch sides and repeat. Do 3 sets.

Why it’s better: More muscle challenge in the hips and butt, thanks to extra work needed to keep you stabilized.

Skip plank, do: Get down, get up

 

Stand with feet hip-distance apart in front of a bench, back to bench, hands together in front of chest. Bend knees and push hips back (keep knees over ankles) to come to sitting on bench.

Brace core and lean torso back while lifting and straightening legs to come into V-position, balancing on sitting bones; open arms out to sides. Slowly lower feet and return to starting position. Do 3 sets of 15 reps.

Why it’s better: This move elevates your heart rate much more than a plank and is more challenging to your leg, hip, butt, and deep core muscles.

Source: Health.com

R.S

Study Reveals the Face of Sleep Deprivation

A new study finds that sleep deprivation affects facial features such as the eyes, mouth and skin, and these features function as cues of sleep loss to other people.

Results show that the faces of sleep-deprived individuals were perceived as having more hanging eyelids, redder eyes, more swollen eyes and darker circles under the eyes. Sleep deprivation also was associated with paler skin, more wrinkles or fine lines, and more droopy corners of the mouth. People also looked sadder when sleep-deprived than after normal sleep, and sadness was related to looking fatigued.

"Since faces contain a lot of information on which humans base their interactions with each other, how fatigued a person appears may affect how others behave toward them," said Tina Sundelin, MSc, lead author and doctoral student in the department of psychology at Stockholm University in Stockholm, Sweden. "This is relevant not only for private social interactions, but also official ones such as with health care professionals and in public safety."

The study, which appears in the September issue of the journal Sleep, was conducted at the Karolinska Institute in Stockholm, Sweden. Ten subjects were photographed on two separate occasions: after eight hours of normal sleep and after 31 hours of sleep deprivation. The photographs were taken in the laboratory at 2:30 p.m. on both occasions. Forty participants rated the 20 facial photographs with respect to 10 facial cues, fatigue and sadness.

According to the authors, face perception involves a specialized neuronal network and is one of the most developed visual perceptual skills in humans. Facial appearance can affect judgments of attributes such as trustworthiness, aggressiveness and competence.

Source : Science Daily

N.H.Khider

Stroke Risk Similar Among Men and Women Smokers Worldwide

 

 

 

Smoking cigarettes may cause similar stroke risks for men and women, but women smokers may be at greater risk for a more deadly and uncommon type of stroke, according to new research in the American Heart Association journal Stroke.

When compared to non-smokers of the same gender, smoking increases the risk of having any type of stroke by 60 to 80 percent in women and men.

Researchers said the finding is intriguing because other studies have found strong evidence that smoking conveys a much higher risk of heart disease -- which shares a common disease process with stroke -- for women than for men.

Researchers compared data from more than 80 international studies that were published between 1966 and 2013. They found that smoking is linked to more than a 50 percent greater risk of ischemic stroke the most common stroke -- one that's caused by a blood clot- in both men and women. However, for the more deadly type of stroke -- one that is caused by a brain bleed, known as a hemorrhagic stroke -- smoking resulted in a 17 percent greater risk in women than in men.

Moreover, compared to men who smoke, the risk for women who smoke was about 10 percent higher in Western countries -- possibly reflecting a greater cumulative exposure to smoking -- than in Asian countries.

The study also found evidence that men and women who smoke can significantly reduce their stroke risk by quitting smoking.

Researchers suggested that the greater risk for bleeding stroke among women might be due to hormones and how nicotine impacts blood fats. It seems that fats, cholesterol and triglycerides increase to a greater extent in women who smoke compared with men who smoke, increasing their risk for coronary heart disease to a greater extent than in male smokers.

"Cigarette smoking is a major risk factor for stroke for both men and women, but fortunately, quitting smoking is a highly effective way to lower your stroke risk," said Rachel Huxley, lead author of the study and Professor, School of Population Health, University of Queensland, in Brisbane, Australia. "Tobacco control policies should be a mainstay of primary stroke prevention programs.

Source : Science daily

N.H.Khider

 

 

 

Short walks 'could cut diabetes risk in older people'

Walking for 15 minutes after meals could prevent "potentially damaging" blood sugar spikes

A 15-minute walk after each meal could prevent older people developing type-2 diabetes, a study has found.

The post-meal walks control blood sugar as well as one long walk, research by George Washington University suggested.

Elevated blood sugar after meals could increase the risk of type-2 diabetes, so resting after eating "is the worst thing you can do", the study said.

Diabetes UK said there were "small differences" between exercise routines - but any activity was beneficial.

The US study was the first to test short bouts of exercise in the "risky period" following meals, when blood sugar can rise rapidly, lead author Loretta DiPietro said.

'Blunting effect'

She said high blood sugar after meals was a key risk factor in the progression from impaired glucose tolerance - what the study called "pre-diabetes" - to type-2 diabetes and cardiovascular disease.

The study found three 15-minute walks were as effective at reducing blood sugar over a 24-hour period as one 45-minute walk of the same "easy-to-moderate" pace.

But walking after food was "significantly more effective" at "blunting the potentially damaging elevations in post-meal blood sugar commonly observed in older people".

The important take-home message is that doing any physical activity, even at a low intensity, is good for you.”

Dr Matthew Hobbs Head of research, Diabetes UK

Older people may be "particularly susceptible" to poor blood sugar control after meals due to insulin resistance in the muscles and slow or low insulin secretion from the pancreas, the researchers said.

They found the best time to walk was after the evening meal, which is often the largest of the day and therefore causes the greatest rise in blood sugar.

More research needed

This increase often lasted "well into the night and early morning", the study found, but it was "curbed significantly" as soon as people started to walk.

Researchers studied 10 people aged 60 and over who were at risk of developing type-2 diabetes due to higher-than-normal levels of fasting blood sugar and insufficient physical activity.

Dr DiPietro said the findings could lead to an "inexpensive strategy" for preventing type-2 diabetes, but said the results must be confirmed by larger trials.

Weight loss and exercise are widely accepted as key ways to prevent type-2 diabetes, which occurs when the body does not produce enough insulin to function properly, or the body's cells do not react to insulin.

Diabetes UK estimates there are up to seven million UK people at "high risk" of developing type-2 diabetes.

Dr Matthew Hobbs, the charity's head of research, said the study reinforced the message that exercise was "extremely important" to reduce the risk.

Talking about the comparison between one 45-minute walk and three 15-minute walks after meals, he added: "Although there were some small differences, the important take-home message is that doing any physical activity, even at a low intensity, is good for you

Source : BBC

N.H.Khider