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Comment: Interesting, but N=1 and... (Score 5, Interesting) 284

by dhj (#47395005) Attached to: Consciousness On-Off Switch Discovered Deep In Brain

From TFA:

Anil Seth, who studies consciousness at the University of Sussex, UK, warns that we have to be cautious when interpreting behaviour from a single case study. The woman was missing part of her hippocampus, which was removed to treat her epilepsy, so she doesn't represent a "normal" brain, he says.

Normally a scientist will not ethically be able to put deep brain electrodes in a person, but this was likely part of a larger experiment related to the hippocampus surgery. It will be interesting to see if similar cases present similar behaviors and more interesting if the same thing happens in someone with a full hippocampus.

Comment: Re:Ghash.IO is not consistently over 51%, yet anyw (Score 1) 281

by dhj (#47245651) Attached to: Bitcoin Security Endangered By Powerful Mining Pool

Is it 51% or 50%+1? There is a big difference. If it's 51% then DDOS as soon as someone gets 50%-1 would work to prevent an exploit. If it's 50%+ then now many false transactions could they make at 51% (or 50%+2) before the DDOS is activated? If it's 50%+ then maybe the DDOS needs to come at 49% or 48% by community agreement. It does set an unsettling precedent that there could be DDOS battles over percent hashing contributions.

On the other hand, maybe this is enforcement that a bitcoin fork needs -- explicit support for mining pools. Such that the ability to get to say 40% by any one actor (pool or individual) is explicitly guarded against. There could be some sort of enforced diminishing returns with viability consensus like transaction consensus. Surely if you are trusting transactions to hash consensus you could also trust "ability or degree to contribute" to the same mechanism. If no-one could get over 48% then no-one could get over 50%. Does anyone know if that's a possible solution?

Does a mining pool really provide the ability to perform a 50%+ attack? They aren't running custom clients are they? Would it require ALL members of the mining pool to collude in the exploit?

Comment: Re:Americans are bad at math (Score 1) 290

by dhj (#38105498) Attached to: The $443 Million Smallpox Vaccine That Nobody Needs

Lets examine how much time $443 million will buy us for budget examination... The 2011 budget expenditures are an estimated $3.82 trillion. So $443 million out of $3.82 trillion is 0.000116 of our budget. or 0.0116 % of the budget. If we spread that spending evenly throughout the year then 0.0116% of the 8760 hours in the year accounts for 0.99 hours. That's right -- less than one hour. That $443 million dollars will buy us less than one hour of time for budget examination. The cost of the wars in Iran and Iraq, however, was over $1 trillion. That would have bought us over 9 days per year every year over the last 10 years.

Comment: Re:Battery Comparison (Score 4, Informative) 103

by dhj (#36925962) Attached to: MIT Unveils Sun-Free Photovoltaics

Good point... The summary left off an important bit of information from TFA:

"Based on that technology, MIT researchers have made a button-sized power generator fueled by butane that can run three times longer than a lithium-ion battery of the same weight; the device can then be recharged instantly, just by snapping in a tiny cartridge of fresh fuel"

So... using this to convert butane to electrical energy it lasts three times longer than a lithium-ion battery of the same weight.

But if you look at energy density of the two fuel sources: http://en.wikipedia.org/wiki/Energy_density

You find that butane/propane/gas/diesel is about 45 megajoules / kg and Li-ion batteries store about 0.75 megajoule / kg. Converted energy 2.25 megajoules (3x Li-Ion) out of stored energy 45 megajoules = 5% efficiency rate converting butane heat to electrical energy using this device.

--David

Comment: Re:Linux support (Score 1) 214

by dhj (#36883316) Attached to: Blockbuster Trying To Woo Disgruntled Netflix Customers

News flash: There is nothing preventing companies from developing DRM or closed binaries on linux. nVidia already has closed binaries, hulu (with drm obviously) runs on a linux OS. The reason companies don't support linux desktop is solely because the linux desktop market is so small that companies do not see a profit benefit in supporting it. So email your favorite(?) company and let them know you are a linux user and you would like for them to support linux.

Comment: Rapid Keyword Searches (Score 1) 591

by dhj (#36240388) Attached to: Mozilla Labs: the URL Bar Has To Go

Replace the URL bar with a tool to support more than just one command? Isn't that what keyword searches are for? I find the firefox URL bar to be extremely useful when combined with keyword searches. Here's how:

Go to any search field for instance the google search box, right click and choose "Add a Keyword for this Search...".

Give the search a single character "keyword" (eg g for google).

Now when you want to do a search you can do the following sequence:

Ctl-L # access the URL bar
Keyword [SEARCH TERMS] # eg "g slashdot" will perform a google search for slashdot

These are some of the keyword searches I use most often:

p for pubmed
g for google
gs for google scholar
gm for google maps
w for wikipedia
d for duckduckgo
ed for english dictionary
sd for spanish dictionary

The URL bar is by far the most useful feature of Firefox!

Comment: Re:How can it be tied to local time zone? (Score 1) 673

by dhj (#36199742) Attached to: Ask Slashdot: What To Do When the Rapture Comes?

You and the GP are missing the point here. God, obviously, will borrow Santa Clause's sleigh. Santa doesn't deliver all the presents at once, right? It takes time for him to ride his sleigh across the sky. So *logically* God will be driving Santa's magic sleigh across the sky approximately 6 hours behind the sun. Or maybe he's hitching a ride with FSM.

Comment: Re:Hydrogen (Score 1) 436

by dhj (#36161036) Attached to: What's Your Favorite Renewable Energy

Ummm.. You guys do realize that "hydropower" means hydroelectric power? As in dammed rivers. Not "hydrogen power" as in hydrogen batteries? The parent is right, "hydrogen power" is just a form of portable energy. The GP whooshed. All of the alternative energies listed consist of converting a significant natural energy resource (like shining sun, blowing wind ... falling water) into electricity, with hamster power obviously being our most precious natural resource.

+ - The DoD Wants All Its Robots To Collaborate on the-> 1

Submitted by epdp14
epdp14 (1318641) writes "If the idea of being hunted by an unmanned aerial drone is unnerving the thought of multiple robots planning a coordinated attack is downright frightening. Unfortunately for those who have to worry about such things, the DoD is working on software tools that allow robots in the sky and on the ground to do exactly that.

The Collaborative Unmanned Systems Technology Demonstrator (CUSTD) system is explained something like this: Aerial drones can pick out subjects from the air, but depending on a particular drone’s sensor array (for weight reasons, different drones carry different sensors) it may not be able to follow a target indoors or through a crowded urban area. So it calls in a few friends."

Link to Original Source
Moon

Microwave Map of Entire Moon Revealed 82

Posted by samzenpus
from the quickest-route-mode dept.
Zothecula writes "The first complete microwave image of the Moon taken by Chinese lunar satellite Chang'E-1 has been revealed. Chang'E-1 is China's first scientific mission to explore planetary bodies beyond Earth and the on-board Lunar Microwave Radiometer has made it possible for the first time to globally map the Moon in microwave frequencies. Radar observations of the Moon are unable to provide thermal information, and microwave observations taken from Earth cannot reach the far side of the moon. So Chang'E-1's (CE-1) orbit was conducted at an altitude of 200km (124 miles) and allowed it to observe every location of the moon with a nadir view and at high spatial resolution."
Earth

+ - Self Assembling Photovoltaic Cells->

Submitted by dhj
dhj (110274) writes "MIT scientists have developed a self-assembling photovoltaic cell in a petri dish. Phospholipids (think cell membranes) form disks which act as the structural support for light responsive molecules. Carbon nanotubes help to align the disks and conduct electricity generated by the system with 40% efficiency. The assembly process is reversible using surfactants to break up the phospholipids. When filters are used to remove the surfactants the system reassembles with no loss of efficiency even over multiple assembly/disassembly cycles. The results were published September 5th in Nature Chemistry."
Link to Original Source

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