Preventing “500 Internal Server Error” for uploaded files on IIS PHP Sites

You may be getting “500 Internal Server Error” upon requesting a uploaded images of a wordpress / php website running on IIS7+ / Windows Server. This same error can be noted as url rewrite error on some debugging tools (developer tools) like chrome inspector. Also the same error can be noted as 500.50.

Nature of the Problem:

This is a very simple problem resulting because of the insufficient permission to read the requested file using the user which is running the PHP service on the windows server machine.


For WordPress website

  1. Navigate to your WordPress site physical location
  2. Go to Wp-Content directory
  3. Right-Click uploads directory / folder and select ‘Properties’
  4. Go to ‘Security’ tab
  5. Click Edit
  6. Select ‘IUSR’ under group or user names
  7. Select ‘Read & Execute’ under permissions for IUSR
  8. Click ‘Apply’ and ‘Ok’
Correct Permission -uploads directory of WordPress on IIS
Correct Permission -uploads directory of WordPress on IIS

For Regular PHP websites

Follow the same procedures as the WordPress website. Note that the directory you need to give the permission to the ‘IUSR’ is the temporary directory specified in your ‘php.ini’ configuration file.

Astronomers just discovered a Morse code message in the dunes of Mars

NASA has spotted a series of strange, dark dunes on Mars that look uncannily like the dots and dashes that make up Morse code.

This isn’t the first time researchers have spotted this pattern in the sands of Mars, but thanks to its unique topography, this dune field – just south of the planet’s north pole – shows them in clearer detail than usual, allowing scientists to translate the message for the first time.

To be clear, this message is naturally formed – just like the dunes here on Earth, the dots and dashes of the dunes were carved out by the direction of the wind. There’s no spooky alien stuff at play here, promise.

As a press release from NASA explains, what makes the patterns in this dune so prominent is the fact that it’s found inside a natural circular depression, which means there’s a limited amount of sand available to be pushed around by the local winds.

The long ‘dashes’ are formed by bi-directional winds, which means wind that’s travelling at right angles to the dune.

Over time, wind coming from either direction funnels the material into a long, dark line, as you can see in the close-up image below:

NASA/JPL/University of Arizona
NASA/JPL/University of Arizona

The Martian ‘dots’ are officially known as ‘barchanoid dunes‘, and are a little more mysterious.

Geophysicists believe they’re formed when something interrupts the production of the linear dunes – but NASA still isn’t quite sure what that is, and figuring it out is part of the reason they were photographing the region.

These images were taken by the High Resolution Imaging Science Experiment (HiRISE) camera, which is on board the Mars Reconnaissance Orbiter, which has been photographing the Red Planet for the past decade.

With more observation, geophysicists are hoping that they’ll be able to figure out more about how the dunes on the surface of Mars form, and what that can tell us about the potential habitability of the planet.

But while they’re figuring that out, NASA planetary scientist Veronica Bray translated the Morse code message for Maddie Stone over at Gizmodo.

So what do the sands of Mars have to tell us? According to Bray:


It’s very deep stuff – and not intended as anything other than a bit of geophysial fun.

But reading the sands of Mars might one day help us better understand life on the surface of our potential future outpost, so it’s worth paying attention.


Source: Science Alert Gizmodo

New design points a path to the ‘ultimate’ battery

Many of the technologies we use every day have been getting smaller, faster and cheaper each year — with the notable exception of batteries. Apart from the possibility of a smartphone which lasts for days without needing to be charged, the challenges associated with making a better battery are holding back the widespread adoption of two major clean technologies: electric cars and grid-scale storage for solar power. Credit: © Eyematrix / Fotolia

Scientists have developed a working laboratory demonstrator of a lithium-oxygen battery which has very high energy density, is more than 90% efficient, and, to date, can be recharged more than 2000 times, showing how several of the problems holding back the development of these devices could be solved.

Lithium-oxygen, or lithium-air, batteries have been touted as the ‘ultimate’ battery due to their theoretical energy density, which is ten times that of a lithium-ion battery. Such a high energy density would be comparable to that of gasoline — and would enable an electric car with a battery that is a fifth the cost and a fifth the weight of those currently on the market to drive from London to Edinburgh on a single charge.

However, as is the case with other next-generation batteries, there are several practical challenges that need to be addressed before lithium-air batteries become a viable alternative to gasoline.

Now, researchers from the University of Cambridge have demonstrated how some of these obstacles may be overcome, and developed a lab-based demonstrator of a lithium-oxygen battery which has higher capacity, increased energy efficiency and improved stability over previous attempts.

Their demonstrator relies on a highly porous, ‘fluffy’ carbon electrode made from graphene (comprising one-atom-thick sheets of carbon atoms), and additives that alter the chemical reactions at work in the battery, making it more stable and more efficient. While the results, reported in the journal Science, are promising, the researchers caution that a practical lithium-air battery still remains at least a decade away.

“What we’ve achieved is a significant advance for this technology and suggests whole new areas for research — we haven’t solved all the problems inherent to this chemistry, but our results do show routes forward towards a practical device,” said Professor Clare Grey of Cambridge’s Department of Chemistry, the paper’s senior author.

Many of the technologies we use every day have been getting smaller, faster and cheaper each year — with the notable exception of batteries. Apart from the possibility of a smartphone which lasts for days without needing to be charged, the challenges associated with making a better battery are holding back the widespread adoption of two major clean technologies: electric cars and grid-scale storage for solar power.

“In their simplest form, batteries are made of three components: a positive electrode, a negative electrode and an electrolyte,” said Dr Tao Liu, also from the Department of Chemistry, and the paper’s first author.

In the lithium-ion (Li-ion) batteries we use in our laptops and smartphones, the negative electrode is made of graphite (a form of carbon), the positive electrode is made of a metal oxide, such as lithium cobalt oxide, and the electrolyte is a lithium salt dissolved in an organic solvent. The action of the battery depends on the movement of lithium ions between the electrodes. Li-ion batteries are light, but their capacity deteriorates with age, and their relatively low energy densities mean that they need to be recharged frequently.

Over the past decade, researchers have been developing various alternatives to Li-ion batteries, and lithium-air batteries are considered the ultimate in next-generation energy storage, because of their extremely high energy density. However, previous attempts at working demonstrators have had low efficiency, poor rate performance, unwanted chemical reactions, and can only be cycled in pure oxygen.

What Liu, Grey and their colleagues have developed uses a very different chemistry than earlier attempts at a non-aqueous lithium-air battery, relying on lithium hydroxide (LiOH) instead of lithium peroxide (Li2O2). With the addition of water and the use of lithium iodide as a ‘mediator’, their battery showed far less of the chemical reactions which can cause cells to die, making it far more stable after multiple charge and discharge cycles.

By precisely engineering the structure of the electrode, changing it to a highly porous form of graphene, adding lithium iodide, and changing the chemical makeup of the electrolyte, the researchers were able to reduce the ‘voltage gap’ between charge and discharge to 0.2 volts. A small voltage gap equals a more efficient battery — previous versions of a lithium-air battery have only managed to get the gap down to 0.5 — 1.0 volts, whereas 0.2 volts is closer to that of a Li-ion battery, and equates to an energy efficiency of 93%.

The highly porous graphene electrode also greatly increases the capacity of the demonstrator, although only at certain rates of charge and discharge. Other issues that still have to be addressed include finding a way to protect the metal electrode so that it doesn’t form spindly lithium metal fibres known as dendrites, which can cause batteries to explode if they grow too much and short-circuit the battery.

Additionally, the demonstrator can only be cycled in pure oxygen, while the air around us also contains carbon dioxide, nitrogen and moisture, all of which are generally harmful to the metal electrode.

“There’s still a lot of work to do,” said Liu. “But what we’ve seen here suggests that there are ways to solve these problems — maybe we’ve just got to look at things a little differently.”

“While there are still plenty of fundamental studies that remain to be done, to iron out some of the mechanistic details, the current results are extremely exciting — we are still very much at the development stage, but we’ve shown that there are solutions to some of the tough problems associated with this technology,” said Grey.

Story Source:

The above post is reprinted from materials provided by University of Cambridge. Note: Materials may be edited for content and length.

Journal Reference:

  1. T. Liu, M. Leskes, W. Yu, A. J. Moore, L. Zhou, P. M. Bayley, G. Kim, C. P. Grey. Cycling Li-O2 batteries via LiOH formation and decomposition. Science, 2015; 350 (6260): 530 DOI: 10.1126/science.aac7730

Images of pleasure, winning have unique distracting power

It is hard to ignore positive images. Credit: © Monkey Business / Fotolia
It is hard to ignore positive images.
Credit: © Monkey Business / Fotolia


Images related to pleasure or winning attract attention from demanding tasks, while equally intense but negative images and those associated with losing can be fully ignored, finds a new UCL study.

51 volunteers completed attention tasks involving search for ‘target’ items. They were found to be highly distracted by emotional images, whether positive or negative, when the search was easy. However when the search was harder and demanded high focus of attention people were able to completely ignore the negative images, while the positive images continued to be highly distracting.

Positive images included graphic photographs of romantic scenes, happy faces, and neutral faces that were previously associated with winning points in a betting task. Negative images included gory photographs, angry faces and neutral faces previously associated with losing points in the betting task.

The study, published in the journal Emotion, suggests that it is easier to ignore negative images than positive ones when we are focusing on other things.

“If someone is busy, the best way to capture their attention is with something related to pleasure,” explains study author Professor Nilli Lavie (UCL Institute of Cognitive Neuroscience). “For example adverts from charities often use images of suffering to encourage donations. Our study suggests that these images could be overlooked by people who are engaged in other activities such as using their phones, reading the newspaper, or forwarding their TV recordings to resume the program they were watching. To capture the attention from other activities, charities could consider using more positive images such as happy people whose lives have been improved by donations.”

The effect was seen not only with intrinsically positive images but also neutral images that were associated with winning in a betting game. Six neutral face images were used with different odds of winning or losing points. Participants were asked to choose between different pairs to maximise points, but these did not represent real money. By the end of the 15-minute game, the patterns of ‘winning’ and ‘losing’ faces were clear; participants consistently chose faces with high odds of winning and low odds of losing.

“The attention-grabbing power of images associated with winning meaningless points is staggering,” says Professor Lavie. “While people were able to ignore graphic images of mutilated bodies during the more difficult task, neutral, expressionless faces associated with winning still distracted them. People appear to be tuned to the prospects of winning. This could suggest a new way of marketing as any neutral image such as a brand logo can be used to capture attention, if the consumer is offered to play in some betting game and the image is associated with winning.

“The results are also surprising from an evolutionary perspective, as one would expect the brain to pay most attention to negative images because they can indicate potential threats. Our findings may reflect the changing priorities of modern Western society, where we face relatively few immediate threats to our lives. In this safe space, our minds may be more focused on pleasure seeking instead of paying attention to potential harm. The power of positive images and those associated with winning may be a symptom of our competitive, hedonistic society.”

Story Source:

The above post is reprinted from materials provided by University College London. Note: Materials may be edited for content and length.

Journal Reference:

  1. Rashmi Gupta, Young-Jin Hur, Nilli Lavie. Distracted by Pleasure: Effects of Positive Versus Negative Valence on Emotional Capture Under Load.. Emotion, 2015; DOI: 10.1037/emo0000112

More than 11 moles on your arm could indicate higher risk of melanoma

Naevus (mole) count is one of the most important markers of risk for skin cancer despite only 20 to 40 per cent of melanoma arising from pre-existing moles. Credit: © phanuwatnandee / Fotolia
Naevus (mole) count is one of the most important markers of risk for skin cancer despite only 20 to 40 per cent of melanoma arising from pre-existing moles.
Credit: © phanuwatnandee / Fotolia

Researchers at King’s College London have investigated a new method that could be used by GPs to quickly determine the number of moles on the entire body by counting the number found on a smaller ‘proxy’ body area, such as an arm.

Naevus (mole) count is one of the most important markers of risk for skin cancer despite only 20 to 40 per cent of melanoma arising from pre-existing moles. The risk is thought to increase by two to four per cent per additional mole on the body, but counting the total number on the entire body can be time consuming in a primary care setting.

Previous studies on a smaller scale have attempted to identify mole count on certain body sites as a proxy to accurately estimate the number on the body as a whole and found that the arm was the most predictive.

This study, funded by the Wellcome Trust, used a much larger sample of participants to identify the most useful ‘proxy’ site for a full body mole count as well as the ‘cut off’ number of moles that can be used to predict those at the highest risk of developing skin cancer.

The researchers used data from 3594 female Caucasian twins between January 1995 and December 2003 as part of the TwinsUK study protocol. Twins underwent a skin examination including recording skin type, hair and eye colour and freckles as well as mole count on 17 body sites performed by trained nurses. This was then replicated in a wider sample of male and female participants from a UK melanoma case control study published previously.

Scientists found that the count of moles on the right arm was most predictive of the total number on the whole body. Females with more than seven moles on their right arm had nine times the risk of having more than 50 on the whole body and those with more than 11 on their right arm were more likely to have over 100 on their body in total, meaning they were at a higher risk of developing a melanoma.

These findings could help GPs to more easily identify those at the highest risk of developing a melanoma (skin cancer).

Scientists also found that the area above the right elbow was particularly predictive of the total body count of moles. The legs were also strongly associated with the total count as well as the back area in males.

Lead author, Simone Ribero of the Department of Twin Research & Genetic Epidemiology said: ‘This study follows on from previous work to identify the best proxy site for measuring the number of moles on the body as a whole. The difference here is that it has been done on a much larger scale in a healthy Caucasian population without any selection bias and subsequently replicated in a case control study from a similar healthy UK population, making the results more useful and relevant for GPs.

‘The findings could have a significant impact for primary care, allowing GPs to more accurately estimate the total number of moles in a patient extremely quickly via an easily accessible body part. This would mean that more patients at risk of melanoma can be identified and monitored.’

Story Source:

The above post is reprinted from materials provided by King’s College London. Note: Materials may be edited for content and length.

Journal Reference:

  1. S. Ribero, D. Zugna, S. Osella-Abate, D. Glass, P. Nathan, T. Spector, V. Bataille. Prediction of high naevus count in a healthy UK population to estimate melanoma risk. British Journal of Dermatology, 2015; DOI: 10.1111/bjd.14216

What is Pointer?

What is Pointer?

In computer science, a pointer is a programming language object, whose value refers to (or “points to”) another value stored elsewhere in the computer memory using its address. A pointer references a location in memory, and obtaining the value stored at that location is known as dereferencing the pointer.

As an analogy, a page number in a book’s index could be considered a pointer to the corresponding page; dereferencing such a pointer would be done by flipping to the page with the given page number.

The term “Pointer” can also be defined as

  1. A variable does not store a value but store the address of the memory space which contains the value.
  2. A variable that contains the address of a location in memory. The location is the starting point of an allocated object, such as an object or value type, or the element of an array.
  3. A value that designates the address (i.e., the location in memory), of some value.
  4. Variables that hold a memory location.
  5. A memory address.

In general, Pointer is a long thin piece of metal on a scale or dial that moves to indicate a figure or position.

Artificial Skin Lets Person Feel Pressure

Human finger touches robotic finger. The transparent plastic and black device on the golden "fingertip" is the skin-like sensor developed by Stanford engineers. This sensor can detect pressure and transmit that touch sensation to a nerve cell. The goal is to create artificial skin, studded with many such miniaturized sensors, to give prosthetic appendages some of the sensory capabilities of human skin. Credit: Bao Lab
Human finger touches robotic finger. The transparent plastic and black device on the golden “fingertip” is the skin-like sensor developed by Stanford engineers. This sensor can detect pressure and transmit that touch sensation to a nerve cell. The goal is to create artificial skin, studded with many such miniaturized sensors, to give prosthetic appendages some of the sensory capabilities of human skin.
Credit: Bao Lab

Stanford engineers have created a plastic “skin” that can detect how hard it is being pressed and generate an electric signal to deliver this sensory input directly to a living brain cell.

Zhenan Bao, a professor of chemical engineering at Stanford, has spent a decade trying to develop a material that mimics skin’s ability to flex and heal, while also serving as the sensor net that sends touch, temperature and pain signals to the brain. Ultimately she wants to create a flexible electronic fabric embedded with sensors that could cover a prosthetic limb and replicate some of skin’s sensory functions.

Bao’s work, reported today in Science, takes another step toward her goal by replicating one aspect of touch, the sensory mechanism that enables us to distinguish the pressure difference between a limp handshake and a firm grip.

“This is the first time a flexible, skin-like material has been able to detect pressure and also transmit a signal to a component of the nervous system,” said Bao, who led the 17-person research team responsible for the achievement.

Benjamin Tee, a recent doctoral graduate in electrical engineering; Alex Chortos, a doctoral candidate in materials science and engineering; and Andre Berndt, a postdoctoral scholar in bioengineering, were the lead authors on the Science paper.

Digitizing touch

The heart of the technique is a two-ply plastic construct: the top layer creates a sensing mechanism and the bottom layer acts as the circuit to transport electrical signals and translate them into biochemical stimuli compatible with nerve cells. The top layer in the new work featured a sensor that can detect pressure over the same range as human skin, from a light finger tap to a firm handshake.

Five years ago, Bao’s team members first described how to use plastics and rubbers as pressure sensors by measuring the natural springiness of their molecular structures. They then increased this natural pressure sensitivity by indenting a waffle pattern into the thin plastic, which further compresses the plastic’s molecular springs.

To exploit this pressure-sensing capability electronically, the team scattered billions of carbon nanotubes through the waffled plastic. Putting pressure on the plastic squeezes the nanotubes closer together and enables them to conduct electricity.

This allowed the plastic sensor to mimic human skin, which transmits pressure information as short pulses of electricity, similar to Morse code, to the brain. Increasing pressure on the waffled nanotubes squeezes them even closer together, allowing more electricity to flow through the sensor, and those varied impulses are sent as short pulses to the sensing mechanism. Remove pressure, and the flow of pulses relaxes, indicating light touch. Remove all pressure and the pulses cease entirely.

The team then hooked this pressure-sensing mechanism to the second ply of their artificial skin, a flexible electronic circuit that could carry pulses of electricity to nerve cells.

Importing the signal

Bao’s team has been developing flexible electronics that can bend without breaking. For this project, team members worked with researchers from PARC, a Xerox company, which has a technology that uses an inkjet printer to deposit flexible circuits onto plastic. Covering a large surface is important to making artificial skin practical, and the PARC collaboration offered that prospect.

Finally the team had to prove that the electronic signal could be recognized by a biological neuron. It did this by adapting a technique developed by Karl Deisseroth, a fellow professor of bioengineering at Stanford who pioneered a field that combines genetics and optics, called optogenetics. Researchers bioengineer cells to make them sensitive to specific frequencies of light, then use light pulses to switch cells, or the processes being carried on inside them, on and off.

For this experiment the team members engineered a line of neurons to simulate a portion of the human nervous system. They translated the electronic pressure signals from the artificial skin into light pulses, which activated the neurons, proving that the artificial skin could generate a sensory output compatible with nerve cells.

Optogenetics was only used as an experimental proof of concept, Bao said, and other methods of stimulating nerves are likely to be used in real prosthetic devices. Bao’s team has already worked with Bianxiao Cui, an associate professor of chemistry at Stanford, to show that direct stimulation of neurons with electrical pulses is possible.

Bao’s team envisions developing different sensors to replicate, for instance, the ability to distinguish corduroy versus silk, or a cold glass of water from a hot cup of coffee. This will take time. There are six types of biological sensing mechanisms in the human hand, and the experiment described in Science reports success in just one of them.

But the current two-ply approach means the team can add sensations as it develops new mechanisms. And the inkjet printing fabrication process suggests how a network of sensors could be deposited over a flexible layer and folded over a prosthetic hand.

“We have a lot of work to take this from experimental to practical applications,” Bao said. “But after spending many years in this work, I now see a clear path where we can take our artificial skin.”

Story Source:

The above post is reprinted from materials provided by Stanford University. The original item was written by Tom Abate. Note: Materials may be edited for content and length.

Journal Reference:

  1. B.C.K. Tee et al. A skin-inspired organic digital mechanoreceptor. Science, 2015 DOI: 10.1126/science.aaa9306

World’s Lightest Material


Boeing says it’s created the lightest metal ever, a microlattice material which it describes as 99.99% air.

The microlattice is a “3D open-cellular polymer structure” and is made up of interconnecting hollow tubes, each one measuring 1000 times thinner than a human hair.

The material is 100 times lighter than styrofoam, making it the lightest and also one of the strongest materials known to science.

Sophia Yang, a research scientist at HRL laboratories who worked with Boeing on the creation of the material says that the metal is 99.99% air. She compares the material to bone, whereby the outside of the bone is rigid while the inside is mostly hollow, creating an open-cellular structure which means it’s remarkably strong as well as extremely lightweight.

The material has been made primarily for use in in aerospace engineering. Engineers intend to use the microlattice for plane interiors in places such as side-panels, overhead cabins, or walkway areas. This would drastically reduce the overall weight of the aircraft, making it more fuel-efficient and cheaper to run.

Yang also highlights the material’s ability to absorb high levels of impact. Using the “egg challenge” as an example, she explains: “You need to drop an egg from 25 stories and protect that egg… What we can do is design the microlattice to absorb the force that the egg feels. So instead of having an egg that’s wrapped in three feet of bubble wrap, now you have a much smaller package that your egg can sit in.”

The microlattice was originally unveiled in November 2011 and was named one of 10 world-changing innovations by Popular Mechanics.

What is Logical Block Addressing (LBA)?

Logical Block Address (LBA)

Logical block addressing is a technique that allows a computer to address a hard disk larger than 528 megabytes. A Logical Block Address (LBA) is a 28-bit value that maps to a specific cylinder-head-sector address on the disk. 28 bits allows sufficient variation to specify addresses on a hard disk up to 8.4 gigabytes in data storage capacity.

The term “Logical block addressing” can also be defined as

  1. An address that defines where data is stored on the hard drive.
  2. A common scheme used for specifying the location of blocks of data stored on computer storage devices.
  3. A run-time function of the system BIOS. The BIOS uses LBA for the following commands: read (with and without retries), read verify, read long, write (with and without retries), write verify, write long, read multiple, write multiple, read DMA, write DMA, seek, and format track.

Machines have nothing on mom when it comes to listening

Credit: University of Montreal
Credit: University of Montreal

More than 99% of the time, two words are enough for people with normal hearing to distinguish the voice of a close friend or relative amongst other voices, says the University of Montreal’s Julien Plante-Hébert. His study, presented at the 18th International Congress of Phonetic Sciences, involved playing recordings to Canadian French speakers, who were asked to recognize on multiple trials which of the ten male voices they heard was familiar to them. “Merci beaucoup” turned out to be all they needed to hear.

Plante-Hébert is a voice recognition doctoral student at the university’s Department of Linguistics and Translation. “The auditory capacities of humans are exceptional in terms of identifying familiar voices. At birth, babies can already recognize the voice of their mothers and distinguish the sounds of foreign languages,” Plante-Hébert said. To evaluate these auditory capacities, he created a series of voice “lineups,” a technique inspired by the well-known visual identification procedure used by police, in which a group of individuals sharing similar physical traits are placed before a witness. “A voice lineup is an analogous procedure in which several voices with similar acoustic aspects are presented. In my study, each voice lineup contained different lengths of utterances varying from one to eighteen syllables. Familiarity between the target voice and the identifier was defined by the degree of contact between the interlocutors.” Forty-four people aged 18-65 participated.

Plante-Hébert found that the participants were unable to identify short utterances regardless of their familiarity with the person speaking. However, with utterances of four or more syllables, such as “merci beaucoup,” the success rate was nearly total for very familiar voices. “Identification rates exceed those currently obtained with automatic systems,” he said. Indeed, in his opinion, the best speech recognition systems are much less efficient than auditory system at best, there is a 92% success rate compared to over 99.9% for humans.

Moreover, in a noisy environment, humans can exceed machine-based recognition because of our brain’s ability to filter out ambient noise. “Automatic speaker recognition is in fact the least accurate biometric factor compared to fingerprints or face or iris recognition,” Plante-Hébert said. “While advanced technologies are able to capture a large amount of speech information, only humans so far are able to recognize familiar voices with almost total accuracy,” he concluded.

Story Source:

The above post is reprinted from materials provided by University of Montreal. Note: Materials may be edited for content and length.