India doctors remove world’s ‘largest brain tumour’

The patient had been living for three years with the 1.8kg tumour, which was larger than his head.

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Health24.com | SEE: Why you are drinking more alcohol than you realise

The information on Health24 is for educational purposes only, and is not intended as medical advice, diagnosis or treatment. If you are experiencing symptoms or need health advice, please consult a healthcare professional. See additional information.

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Laser technology takes Maya archeologists where they’ve never gone before

With the help of airborne laser mapping technology, a team of archaeologists, led by University of Arizona professor Takeshi Inomata, is exploring on a larger scale than ever before the history and spread of settlement at the ancient Maya site of Ceibal in Guatemala.

In a new paper published in the journal PLOS ONE, Inomata and his colleagues explain how they commissioned the use of LiDAR, or light detection and ranging, technology to map a significantly larger area of Ceibal than ever before recorded.

LiDAR provides highly accurate, detailed 3-D maps of ground surface topography. Over the course of just a few days at Ceibal, a small airplane, equipped with lasers powerful enough to peer through the dense jungle canopy, soared above the site, mapping — with a less than 10-centimeter margin of error — the shape, size and location of ancient Maya pyramids, platforms, ceremonial centers, roads, water reservoirs and other structures previously undocumented by archaeologists.

The resulting map covers 470 square kilometers that would have been extremely challenging for archaeologists to reach on foot, and includes the locations of more than 15,000 ancient Maya architectural remains. Previously, archaeologists had information on only about 8 square kilometers and fewer than 1,000 structures in the area.

“This kind of understanding was really unthinkable some years ago, and now suddenly we can have all these data,” Inomata said. “The scale is completely different.”

Inomata and his colleagues used the LiDAR data to reconstruct a timeline of growth and change at Ceibal, building upon what they already knew from previous excavations about when different styles of structures appeared between about 1,000 B.C. and A.D. 950.

They outline their methods in detail in the PLOS ONE paper.

“What we tried to do here was to set up a systematic method of analyzing this LiDAR data over a wide area, and then translate it into an interpretation of temporal sequences and social change,” said Inomata, a professor and Agnese Nelms Haury Chair in Environment and Social Justice in the UA School of Anthropology.

Combining LiDAR and excavation data then allowed the archaeologists to reconstruct settlement patterns over a long period of time.

“Looking at the LiDAR image, you can see the specific types of architecture — pyramids, long structures — and we know from our excavations what time period they’re from. So just looking at the shape of the structures, we can see this network of communities and ceremonial centers from specific periods,” Inomata said.

Lasers Let Humans Explore Challenging Terrain

Mapping an archaeological site in a densely vegetated area such as the Guatemalan jungle is a daunting task — one traditionally done on foot. Because of the challenging terrain, only about 1.9 square kilometers of Ceibal had been completely mapped previously — by Harvard archaeologists in the 1960s — while about 6 more kilometers were surveyed with less detail.

It was in that small area that Inomata and his colleagues have been conducting archaeological excavations for the last 13 years.

Since joining the growing number of researchers who have used the LiDAR surveying method to help with interpretation of archaeological sites, Inomata and his team have gained access to data that would have been nearly impossible to obtain through on-foot surveys. The LiDAR survey, which was conducted by the University of Houston’s National Center for Airborne Laser Mapping, even found a few things that the original on-the-ground mapping done in the 1960s missed.

“The maps that Harvard made were incredibly accurate, considering they were all ground survey, but with LiDAR we found a lot more buildings than were on the map previously, and their locations are very accurate,” said paper co-author Melissa Burham, a UA graduate student in anthropology.

As a growing number of researchers turn to the LiDAR surveying method to aid in the interpretation of archaeological sites, Inomata and his team hope their colleagues in the field may follow a similar process to what they used at Ceibal, which they plan to apply again in their regional survey in the state of Tabasco in Mexico, where they will begin work in February.

“In archaeology, excavation is always important, but you can’t excavate everything, so you look for patterns on a smaller scale that you can extrapolate over a larger region,” said Burham, who co-authored the paper along with Inomata, UA anthropology professor Daniela Triadan and researchers from Guatemala and Japan. “That’s really what this paper aims to do. This can help other people understand growth at other Maya centers and help with dating methods.”

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Locomotion of bipedal dinosaurs might be predicted from that of ground-running birds

A new model based on ground-running birds could predict locomotion of bipedal dinosaurs based on their speed and body size, according to a study published February 21, 2018 in the open-access journal PLOS ONE by Peter Bishop from the Queensland Museum, Australia and colleagues.

Previous research has investigated the biomechanics of ground-dwelling birds to better understand the how bipedal non-avian dinosaurs moved, but it has not previously been possible to empirically predict the locomotive forces that extinct dinosaurs experienced, especially those species that were much larger than living birds. Bishop and colleagues examined locomotion in 12 species of ground-dwelling birds, ranging in body mass from 45g to 80kg, as the birds moved at various speeds along enclosed racetracks while cameras recorded their movements and forceplates measured the forces their feet exerted upon the ground.

The researchers found that many physical aspects of bird locomotion change continuously as speed increases. This supports previous evidence that unlike humans, who have distinct “walking” and “running” gaits, birds move in a continuum from “walking” to “running.” The authors additionally observed consistent differences in gait and posture between small and large birds.

The researchers used their data to construct the biomechanically informative, regression-derived statistical (BIRDS) Model, which requires just two inputs — body mass and speed — to predict basic features of bird locomotion, including stride length and force exerted per step. The model performed well when tested against known data. While more data are needed to improve the model, and it is unclear if it can be extrapolated to animals of much larger body mass, the researchers hope that it might help predict features of non-avian dinosaur locomotion using data from fossils and footprints.

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Materials provided by PLOS. Note: Content may be edited for style and length.

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Sea urchins erode rock reefs, excavate pits for themselves

Through their grazing activity, sea urchins excavate rock and form the pits they occupy. This activity may cause significant bioerosion of temperate reefs, according to a study published February 21, 2018 in the open-access journal PLOS ONE by Michael Russell from Villanova University, U.S., and colleagues.

Sea urchins live in high densities on rocky temperate reefs, and are often so snugly nestled into cavities that researchers have long wondered if they excavate these pits themselves. However, there was no experimental data to support this hypothesis or to assess its environmental consequences. The authors of the present study investigated this question by monitoring purple sea urchins, Strongylocentrotus purpuratus, on flattened rock surfaces in the lab. They used fine- and medium-grain sandstone, mudstone and granite rocks from three Californian reef sites naturally occupied by sea urchins, where the researchers also conducted field measurements.

The researchers found that sea urchins did indeed visibly sculpt the rock, removing material from all the rock surfaces during the laboratory experiment. Rates of excavation varied greatly by rock type in the lab: while each urchin excavated around 32g of medium-grain sandstone over a year, meaning that an average-sized pit could be sculpted in under five years, granite excavation was 37 times slower, so arduous that it would take more than a century to form a pit. Field measurements reflected this difference, with granite pits being shallower, and sea urchins flatter, than their sandstone counterparts.

The authors combined the laboratory rates with urchin density measurements, estimating that on medium-grain sandstone reefs, urchins might produce almost 200 tonnes of sediment per hectare per year. However, excavation rates in the field might differ significantly from laboratory rates. Nonetheless, the authors note that urchin-mediated bioerosion is a potentially important factor in temperate reef coastal erosion, and deserves further investigation.

“What shocked us was the rate of bioerosion — particularly on sandstone,” says Russel. “In the course of feeding, sea urchins scrape the rock surface using their self-sharpening, regenerating teeth, which act as ‘rock picks’ and this process results in the excavation of pits.”

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Materials provided by PLOS. Note: Content may be edited for style and length.

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NHS ‘dangerously’ short of 100,000 staff

Figures show one in 12 posts in England is unfilled – enough to staff 10 large hospitals.

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Should You Go to the ER?

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Health24.com | The purrfect diet for your fat cat

Has your favourite cat become a little tubby?

You can help your fat cat slim down safely. But be forewarned: It won’t happen overnight.

Healthy weight loss

Researchers at the University of Illinois put eight overweight neutered male cats on a diet for 18 weeks. They wanted the cats to lose enough weight to be noticeable but not enough to put their health at risk.

The study was published in the American Journal of Veterinary Research.

“The intent with this diet was a healthy weight loss: getting rid of fat while maintaining lean mass. The big question was how much it takes to make cats lose weight, especially lazy neutered males?” asked Kelly Swanson, a professor in the department of animal sciences.

“It turns out you have to keep reducing their food intake because they’re not very active. It takes a long time,” he said in a university news release.

The goal was to help the cats shed 1.5% of their body weight per week. That’s in line with recommendations from the American Animal Hospital Association.

Changes in gut bacteria

Faster weight loss risks liver trouble. “They can’t handle that much,”  Professon Swanson said.

The researchers started by reducing the cats’ food intake by 20%, and then kept cutting it back every week – just like people might do to see continued results on the scale.

“When we go on a diet ourselves, we might lose a lot of weight in the first few weeks and then hit a road block. Same with these animals,” Professor Swanson said.

“We had to keep going down, but it can be hard to convince a pet owner to do that. You might get owners to reduce intake from 60 to 50g per day, but we’re telling them they might have to go to 45 or 40g. We got really low, but we were monitoring them so they were healthy,” he explained.

Little change in activity level

As the cats lost weight, the researchers noticed that some types of bacteria in their guts became more abundant, while others decreased. These changes may be beneficial but more research is needed, the study authors said.

A 2008 Canadian veterinary Journal article cautioned that for a diet to be satisfactory, it must contain all of the necessary nutrients in the proper proportions, be sufficiently palatable and digestible for the pets to meet their nutritional needs in the volume consumed, and it must be safe.

A 2012 SkeptVet article concluded that there wasn’t a big difference in the effectiveness of dry, raw and cooked diets for cats.

Professor Swanson’s team also watched to see if the cats became more active as they slimmed down.

“Their activity level didn’t change much,” Professor Swanson said. “Toward the end, they were becoming a little more active, but not statistically [significant].”

Even so, he said owners should encourage their cats to get as much exercise as possible by playing with them and placing food bowls farther from their favorite resting spots.

Image credit: iStock

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Health24.com | When do kids need to go to the orthodontist?

Previously orthodontic treatment was carried out on children in their teenage years. Today, however, many children start orthodontic treatment at a much younger age. There are also large numbers of adults receiving orthodontic treatment.

At what age do you consider braces?

Traditional “train-track” braces are fitted to a child’s adult teeth and are used to move, realign and/or rotate a tooth or teeth into the correct position. This is why you’ll usually see children 10 years and older wearing these types of braces.

However, crowded/crooked/skew adult teeth usually manifest because of a space shortage and/or a problem with jaw growth and/or jaw relationships. This can usually be identified in young children, even before many of their adult teeth start coming through.

The big shift in orthodontics has been to check children at a much younger age, identify these issues earlier and intervene before the arrival of the adult teeth.

In many cases, early intervention can provide future adult teeth with all the space they need and the child may not have to wear conventional braces at all.orthodontics, teeth, braces, children, plates

Plates vs. braces

Sometimes using adjustable, removable plates can be successful, especially in young children where they can help the jaw grow to the right size and shape, which creates the space required for the new adult teeth before they come through.

Other times plates may be used first, followed by braces. 

In adults, there are many situations where more simple alignment issues can be corrected using a series of custom-made clear aligners (as can be seen in the image below).

Child using a retainer plate

The fundamental thing in orthodontics is that each case is unique. Each child’s case needs to be assessed properly and a tailor-made treatment plan created for the individual to ensure the best results.

One of the disadvantages of using removable plates for children is that they are removable.

Children often don’t wear their plates as directed, the plates get lost and/or broken and many months of treatment (and a lot of money) can be wasted when a child does not follow instructions.

Tooth and bite conditions to watch out for

We have two jaws, the upper jaw (maxilla), which is part of our skull and cannot move and the movable lower jaw (mandible), which is a long, curved bone with joints on each end.

The lower jaw moves when we speak, chew and swallow. The joints on each end pivot and slide in special sockets at the base of our skull, just in front of our ear openings.

In an ideal orthodontic situation, all our teeth should line up in each jaw the teeth of the lower jaw should fit nicely inside those of the upper jaw when we bite together.

If we have what is called an overbite (Bugs Bunny), it could be because the upper jaw is too far forward and/or too big, or because the lower jaw is too far back and/or too small. Or both.

Similarly, an underbite (bulldog) occurs when the upper jaw is too far back and/or too small or the lower jaw is too far forward and/or too big, or both.

If the teeth are crowded in the lower jaw, it could either be because the lower jaw is too small for all those teeth or because the upper jaw is too small and the lower teeth cannot fit inside upper jaw arch, as they are supposed to.

In many such cases, the teeth in the upper jaw are forced forward by the trapped lower jaw, which can cause the front teeth to protrude outwards.

In teenagers and adults, tooth clenching and/or grinding, migraine headaches, chronic earache and chronic neck, back and shoulder pain can also be associated with a lower jaw which is trapped inside the upper jaw.

Treat case by case

Each child is unique. And so will their orthodontic development and possible treatment.

In many dentists’ and orthodontists’ opinion, the most important development in orthodontics has been the advent of early-intervention orthodontics, where jaw growth and facial development form the new basis of orthodontic planning, instead of trying to straighten crooked adult teeth with braces.

Image credits: iStock

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