lars_doucet writes: Steam's new search page lets you sort by "user rating," but the algorithm they're using is broken. For instance, a DLC pack with a single positive review appears above a major game with a 74% score and 15,000+ ratings.

The current "user rating" ranking system seems to divide everything into big semantic buckets ("Overwhelmingly Positive", "Positive", "Mixed", etc.), stack those in order, then sort each bucket's contents by the total number of reviews per game. Given that Steam reviews skew massively positive, (about half are "very positive" or higher), this is virtually indistinguishable from a standard "most popular" chart.

Luckily, there's a known solution to this problem — use statistical sampling to account for disparate numbers of user reviews, which gives "hidden gems" with statistically significant high positive ratings, but less popularity, a fighting chance against games that are already dominating the charts.

Z00L00K sends this report from New Scientist: Networks shaped like delicate snowflakes are the ones that are easiest to fix when disaster strikes. Power grids, the internet and other networks often mitigate the effects of damage using redundancy: they build in multiple routes between nodes so that if one path is knocked out by falling trees, flooding or some other disaster, another route can take over. But that approach can make them expensive to set up and maintain. The alternative is to repair networks with new links as needed, which brings the price down – although it can also mean the network is down while it happens.

As a result, engineers tend to favor redundancy for critical infrastructure like power networks, says Robert Farr of the London Institute for Mathematical Sciences. So Farr and colleagues decided to investigate which network structures are the easiest to repair. They simulated a variety of networks, linking nodes in a regular square or triangular pattern and looked at the average cost of repairing different breaks, assuming that expense increases with the length of a rebuilt link. ... They found the best networks are made from partial loops around the units of the grid, with exactly one side of each loop missing (abstract). All of these partial loops link together, back to a central source. ... These networks have three levels of hierarchy – major arms sprouting from a central hub that branch and then branch again, but no further. When drawn, they look remarkably like snowflakes, which have a similar branching structure.

00_NOP writes: Children in the U.K. have been taught in metric measures in school since (at least) 1972, but yesterday British Prime Minister David Cameron suggested that they should actually be taught in Imperial measures (which are still in use officially to measure road distances and speeds, but not really anywhere else). Is this because he hasn't a clue about science or because he is catering to a particular political base?

An anonymous reader writes: The founders of the African School for Excellence have an ambitious goal — nothing less than redefining low cost, scalable teaching that brings international standards to the poorest schools in Africa. Their first model school is off to a good start: in just 18 months, all grade 9 students are achieving scores higher than 50% on Cambridge Curriculum Checkpoint tests, and only one student scored less than 50% in math. The national average score in math is 13%. The school relies on a locally designed piece of marking software to function. Their teach-to-pupil ratios are not great, but the teachers are committed to using technology to stretch themselves as far as they can. What's most remarkable is that the school's running costs are already half the cost of a traditional government school, and the quality of education is much, much better. All this, and they're only a year and a half into the program.

Koreantoast writes: Black holes, the stellar phenomena that continue to capture the imagination of scientists and science fiction authors, may not actually exist. According to a paper published by physics professor Laura Mersini-Houghton at the University of North Carolina and Mathematics Professor Harald Pfeiffer of the University of Toronto, as a collapsing star emits Hawking radiation, it also sheds mass at a rate that suggests it no longer has the density necessary to become a black hole — the singularity and event horizon never form. While the arXiv paper with the exact solution has not yet been peer reviewed, the preceding paper by Mersini-Houghton with the approximate solutions was published in Physics Letters B.

"I'm still not over the shock," said Mersini-Houghton. "We've been studying this problem for a more than 50 years and this solution gives us a lot to think about... Physicists have been trying to merge these two theories – Einstein's theory of gravity and quantum mechanics – for decades, but this scenario brings these two theories together, into harmony."

An anonymous reader writes "Pascal-Emmanuel Gobry writes at The Week, "If you ask most people what science is, they will give you an answer that looks a lot like Aristotelian 'science' — i.e., the exact opposite of what modern science actually is. Capital-S Science is the pursuit of capital-T Truth. And science is something that cannot possibly be understood by mere mortals. It delivers wonders. It has high priests. It has an ideology that must be obeyed. This leads us astray. ... Countless academic disciplines have been wrecked by professors' urges to look 'more scientific' by, like a cargo cult, adopting the externals of Baconian science (math, impenetrable jargon, peer-reviewed journals) without the substance and hoping it will produce better knowledge. ... This is how you get people asserting that 'science' commands this or that public policy decision, even though with very few exceptions, almost none of the policy options we as a polity have have been tested through experiment (or can be). People think that a study that uses statistical wizardry to show correlations between two things is 'scientific' because it uses high school math and was done by someone in a university building, except that, correctly speaking, it is not. ... This is how you get the phenomenon ... thinking science has made God irrelevant, even though, by definition, religion concerns the ultimate causes of things and, again, by definition, science cannot tell you about them. ... It also means that for all our bleating about 'science' we live in an astonishingly unscientific and anti-scientific society. We have plenty of anti-science people, but most of our 'pro-science' people are really pro-magic (and therefore anti-science). "

jd writes Identity-based public key encryption works on the idea of using something well-known (like an e-mail address) as the public key and having a private key generator do some wibbly-wobbly timey-wimey stuff to generate a secure private key out if it. A private key I can understand, secure is another matter. In fact, the paper notes that security has been a big hassle in IBE-type encryption, as has revocation of keys. The authors claim, however, that they have accomplished both. Which implies the public key can't be an arbitrary string like an e-mail, since presumably you would still want messages going to said e-mail address, otherwise why bother revoking when you could just change address?

Anyways, this is not the only cool new crypto concept in town, but it is certainly one of the most intriguing as it would be a very simple platform for building mostly-transparent encryption into typical consumer apps. If it works as advertised. I present it to Slashdot readers to engender discussion on the method, RIBE in general and whether (in light of what's known) default strong encryption for everything is something users should just get whether they like it or not.

vinces99 (2792707) writes Using modern statistical tools, a new study led by the University of Washington and the United Nations finds that world population is likely to keep growing throughout the 21st century. The number of people on Earth is likely to reach 11 billion by 2100, the study concludes, about 2 billion higher than widely cited previous estimates. The paper published online Sept. 18 in the journal Science includes the most up-to-date numbers for future world population, and describes a new method for creating such estimates. "The consensus over the past 20 years or so was that world population, which is currently around 7 billion, would go up to 9 billion and level off or probably decline," said corresponding author Adrian Raftery, a UW professor of statistics and of sociology. ... The paper explains the most recent United Nations population data released in July. This is the first U.N. population report to use modern statistics, known as Bayesian statistics, that combines all available information to generate better predictions.

Most of the anticipated growth is in Africa, where population is projected to quadruple from around 1 billion today to 4 billion by the end of the century. The main reason is that birth rates in sub-Saharan Africa have not been going down as fast as had been expected. There is an 80 percent chance that the population in Africa at the end of the century will be between 3.5 billion and 5.1 billion people.

mpicpp sends this news from CNN: In swaths of Syria now controlled by ISIS, children can no longer study math or social studies. Sports are out of the question. And students will be banned from learning about elections and democracy. Instead, they'll be subjected to the teachings of the radical Islamist group. And any teacher who dares to break the rules "will be punished." ISIS revealed its new educational demands in fliers posted on billboards and on street poles. The Sunni militant group has captured a slew of Syrian and Iraqi cities in recent months as it tries to establish a caliphate, or Islamic state, spanning Sunni parts of both countries. Books cannot include any reference to evolution. And teachers must say that the laws of physics and chemistry "are due to Allah's rules and laws." Update: 09/18 16:26 GMT by S : CNN has pulled the story over "concerns about the interpretation of the information provided." They promise to update it when they get the facts straight.

KentuckyFC writes: Most research into the origin of life focuses on the messy business of chemistry, on the nature of self-replicating molecules and on the behavior of autocatalytic reactions. Now one theorist says the properties of information also place important limits on how life must have evolved, without getting bogged down in the biochemical details. The new approach uses information theory to highlight a key property that distinguishes living from non-living systems: their ability to store information and replicate it almost indefinitely. A measure of this how much these systems differ from a state of maximum entropy or thermodynamic equilibrium. The new approach is to create a mathematical model of these informational differences and use it to make predictions about how likely it is to find self-replicating molecules in an artificial life system called Avida. And interestingly, the predictions closely match what researchers have found in practice. The bottom line is that according to information theory, environments favorable to life are unlikely to be unusual.

theodp (442580) writes Unless some things change, UC Davis Prof. Norman Matloff worries that the Statistician could be added to the endangered species list. "The American Statistical Association (ASA) leadership, and many in Statistics academia," writes Matloff, "have been undergoing a period of angst the last few years, They worry that the field of Statistics is headed for a future of reduced national influence and importance, with the feeling that: [1] The field is to a large extent being usurped by other disciplines, notably Computer Science (CS). [2] Efforts to make the field attractive to students have largely been unsuccessful."

Matloff, who has a foot in both the Statistics and CS camps, but says, "The problem is not that CS people are doing Statistics, but rather that they are doing it poorly. Generally the quality of CS work in Stat is weak. It is not a problem of quality of the researchers themselves; indeed, many of them are very highly talented. Instead, there are a number of systemic reasons for this, structural problems with the CS research 'business model'." So, can Statistics be made more attractive to students? "Here is something that actually can be fixed reasonably simply," suggests no-fan-of-TI-83-pocket-calculators-as-a-computational-vehicle Matloff. "If I had my druthers, I would simply ban AP Stat, and actually, I am one of those people who would do away with the entire AP program. Obviously, there are too many deeply entrenched interests for this to happen, but one thing that can be done for AP Stat is to switch its computational vehicle to R."

theodp writes Over at Khan Academy, Salman Khan explains Why I'm Cautious About Telling My Son He's Smart. "Recently," writes Khan, "I put into practice research I had been reading about for the past few years: I decided to praise my son not when he succeeded at things he was already good at, but when he persevered with things that he found difficult. I stressed to him that by struggling, your brain grows. Between the deep body of research on the field of learning mindsets and this personal experience with my son, I am more convinced than ever that mindsets toward learning could matter more than anything else we teach." According to Dr. Carol Dweck, who Khan cites, the secret to raising smart kids is not telling kids that they are. A focus on effort — not on intelligence or ability — says Dweck, is key to success in school and in life.

A while ago you had a chance to ask Andrew "bunnie" Huang about hardware, hacking and his open source hardware laptop Novena. Below you'll find his answers to those questions.

An anonymous reader writes: Dave Munson was thinking about moving, and had a couple broad requirements for a new home: it must be affordable, and its neighborhood must be walkable. Price is easy to chart, but how do you compare the walkability of hundreds of cities? Simple: use math. A website called Walk Score provides rough walkability ratings, but doesn't tell you much about affordability. Munson downloaded the data that went into a city's Walk Score, weighted the relevant variables, and mapped the top results. Then he looked for overlap with the map of areas in his price range. He says, "Capitol Hill, Seattle led the pack. To be honest, I was expecting something a smaller, affordable Midwest town or something, but it the highest scoring areas were usually just outside of major downtowns. Other top areas included Cambridge and Somerville outside of Boston, and the South End in Boston; Columbia Heights, Washington, DC; The Mission District, Lower Haight, and Russian Hill, San Francisco; Midtown, Atlanta; Greenwood, Dyker Heights, Kensington, and Sheepshead Bay, Brooklyn; Graduate Hospital in Philadelphia, where we used to live; Lake View, Chicago; and Five Points, Denver."

An anonymous reader sends news that the 2014 Fields Medals have been awarded for outstanding work in the field of mathematics. The winners are Artur Avila, Manjul Bhargava, Martin Hairer, and Maryam Mirzakhani. Quanta Magazine writes, Mirzakhani is the first woman to win a Fields Medal. The gender imbalance in mathematics is long-standing and pervasive, and the Fields Medal, in particular, is ill-suited to the career arcs of many female mathematicians. It is restricted to mathematicians younger than 40, focusing on the very years during which many women dial back their careers to raise children. Mirzakhani feels certain, however, that there will be many more female Fields medalists in the future. "There are really many great female mathematicians doing great things," she said. Quanta has profiles of the other winners as well (Avila, Bhargava, Hairer), and of Rolf Nevanlinna Prize winner Subhash Khot.

Taco Cowboy writes with this story about new research that finds a strong genetic component to a child's ability in math and reading. "You may think you're better at reading than you are at math (or vice versa), but new research suggests you're probably equally good (or bad) at both. The reason: The genes that determine a person's ability to tackle one subject influence their aptitude at the other, accounting for about half of a person's overall ability. The study, published Tuesday in the journal Nature Communications, used nearly 1,500 pairs of 12-year-old twins to tease apart the effects of genetic inheritance and environmental variables on math and reading ability. The researchers administered a set of math and verbal tests to the children and then compared the performance of different sets of twins. They found that the twins' scores — no matter if they were high or low — were twice as similar among pairs of identical twins as among pairs of fraternal twins. The results indicated that approximately half of the children's math and reading ability stemmed from their genetic makeup.

A complementary analysis of unrelated kids corroborated this conclusion — strangers with equivalent academic abilities shared genetic similarities. What's more, the genes responsible for math and reading ability appear to be numerous and interconnected, not specifically targeted toward one set of skills. These so-called 'generalist genes' act in concert to determine a child's aptitude across multiple disciplines. The finding that one's propensities for math and reading go hand in hand may come as a surprise to many, but it shouldn't. People often feel that they possess skills in only one area simply because they perform slightly worse in the other."

stephendavion writes A legal scholar says he and colleagues have developed an algorithm that can predict, with 70 percent accuracy, whether the US Supreme Court will uphold or reverse the lower-court decision before it. "Using only data available prior to the date of decision, our model correctly identifies 69.7 percent of the Court's overall affirm and reverse decisions and correctly forecasts 70.9% of the votes of individual justices across 7,700 cases and more than 68,000 justice votes," Josh Blackman, a South Texas College of Law scholar, wrote on his blog Tuesday.

StartsWithABang (3485481) writes Based on all the experiments we've ever been able to perform, we're quite certain that our Universe, from the largest scales down to the microscopic, obeys the physical laws of three spatial dimensions (and one time dimension): a four-dimensional spacetime. But that's not the only possibility mathematically. People had experimented with bringing a fifth dimension in to unify General Relativity with Electromagnetism in the past, but that was regarded as a dead-end. Then in the 1970s, an unknown theoretical physicist working on the string model of the strong interactions discovered that by going into the 26th dimension, some incredibly interesting physics emerged, and String Theory was born.

An anonymous reader writes: Amazon has waged a constant battle with publishers over the price of ebooks. They've now publicly laid out their argument and the business math behind it. "We've quantified the price elasticity of e-books from repeated measurements across many titles. For every copy an e-book would sell at $14.99, it would sell 1.74 copies if priced at $9.99. So, for example, if customers would buy 100,000 copies of a particular e-book at $14.99, then customers would buy 174,000 copies of that same e-book at $9.99. Total revenue at $14.99 would be $1,499,000. Total revenue at $9.99 is $1,738,000." They argue that capping most ebooks at $9.99 would be better for everyone, with the money split out 35% to the author, 35% to the publisher, and 30% to Amazon.

Author John Scalzi says Amazon's reasoning and assumptions are a bit suspect. He disagrees that "books are interchangeable units of entertainment, each equally as salable as the next, and that pricing is the only thing consumers react to." Scalzi also points out that Amazon asserts itself as the only revenue stream for authors, which is not remotely true. "Amazon's assumptions don't include, for example, that publishers and authors might have a legitimate reason for not wanting the gulf between eBook and physical hardcover pricing to be so large that brick and mortar retailers suffer, narrowing the number of venues into which books can sell. Killing off Amazon's competitors is good for Amazon; there's rather less of an argument that it's good for anyone else."

New submitter meeotch writes: According to a new study by the Urban Institute, 35% of U.S. adults with a credit history (91% of the adult population of the U.S.) have debt "in collections" — a status generally not acquired until payments are at least 180 days past due. Debt problems seem to be worse in the South, with states hovering in the 40%+ range, while the Northeast has it better, at less than 30%. The study's authors claim their findings actually underrepresent low-income consumers, because "adults without a credit file are more likely to be financially disadvantaged."

Oddly, only 5% of adults have debt 30-180 days past due. This latter fact is partially accounted for by the fact that a broader range of debt can enter "in collections" status than "past due" status (e.g. parking tickets)... But also perhaps demonstrates that as one falls far enough along the debt spiral, escape becomes impossible. Particularly in the case of high-interest debt such as credit cards — the issuers of which cluster in states such as South Dakota, following a 1978 Supreme Court ruling that found that states' usury laws did not apply to banks headquartered in other states.

Even taking into account the folks who lost a parking ticket under their passenger seat, 35% is a pretty shocking number. Anyone have other theories why this number is so much higher than the 5% of people who are just "late"? How about some napkin math on the debt spiral?