C
A
T
E
G
O
R
I
E
S

&

R
E
C
E
N
T

Apple LESS secure than Windows

Posted by tigerhawkvok on March 25, 2009 18:50 in computers , news

From Tom's Hardware via Slashdot:

Alan: So, if you had to make a recommendation, Mac, PC, or Linux? Or do you find them to be equally (in)secure?

Charlie: I'll leave Linux out of the equation since I know my grandma couldn't run it. Between Mac and PC, I'd say that Macs are less secure for the reasons we've discussed here (lack of anti-exploitation technologies) but are more safe because there simply isn't much malware out there. For now, I'd still recommend Macs for typical users as the odds of something targeting them are so low that they might go years without seeing any malware, even though if an attacker cared to target them it would be easier for them.

Alan: Sure, the risk = threat x vulnerability x consequence concept. Macs have low threats but high vulnerability while Vista is the other way around. I recently switched to a Mac myself and wrote about it for Tom's Hardware (and had a lot of angry readers). Like you mentioned earlier, we want to support vendors with the most secure software, but it’s not easy to always figure out which software is the most secure and sometimes the real-world risk is lower with a vulnerable platform with fewer threats.

(Emphasis mine). There, definitive. Macs are less secure than PCs, just no one cares about them. Can the vehement Apple-fanboi crowd be quiet now? For the record — the Charlie here is the winner of Pwn2Own, a hacking contest with real-world software and operating systems. He cracked Leopard in under 2 minutes.

Fossil finds, oh my!

Posted by tigerhawkvok on March 17, 2009 03:24 in dinosaurs , sauropods , news , paleontology

Seems that the news has been an bit heavy on the fossil finds! How about a rundown.

Hesperonychus claw, hotlinked via National Geographic. The claw is on a Canadian penny.

First up is Hesperonychus ("western claw") — as yet, the smallest theropod found in North America. At the time of this writing, the PNAS paper isn't up yet, but in particular PhysOrg has a pretty good synopsis. As the name suggests (via a linguistic kinship to Deinonychus), Hesperonychus elizabethae is a diminuitive dromaeosaurid, approximately 2 kg and 50 cm tall "beating" Albertonykus borealis for title of "smallest North American non-avian dinosaur". It retains the trademark "sickle claw" of the dromaeosaurids, and the hip configuration was one of the primary diagnostic traits used to pin it to dromaeosauridae. The pelvis is also fused, suggesting that this was a mature adult. It's dated to about 75 million years ago (which the PhysOrg article accidentally writes as 45 million years ago, obviously in error at 20 MY after the K-T event).

Picture of the Svalbard excavation, from the New York Times.

The next big find announced today was of an unnamed, massive pliosaur found in the Svalbard region. I'm outright going to say I wish Kit had something to say about this, as I vaguely recall him mentioning this almost a year ago, and he knew some basics about it already. Never mind how he knows, considering it hasn't been published yet — the NYT article is already a pre-publishing press release.

At any rate, this guy was massive. This pliosaur had a skull measuring over 3m long, and the entire animal was probably longer than 15m at over 40 tonnes. Its "nickname" for now is "Predator X". Particularly novel about this find is that it might represent a new family of pliosaurs, which would be rather significant, paleontologically. Initial biomechanical work suggests its bit force would be 2-4 times that of T. rex and more than 10 times that of any extant animal. It was estimated to live about 150 MYA.

Figure 1 from Mud-trapped herd captures evidence of distinctive dinosaur sociality by Varricchio et al. 2008. (property of the authors)

Sinornithomimus dongi (Chinese bird mimic)is the next guy to hit to press. It has the slightly dubious distinction of being discovered when a large immature herd got stuck in a mud trap. It is siginificant in that the herd was apparently all juveniles, and in the number of animals found. With 25 individuals found (aged 1-7), this promises to make Sinornithomimus particularly well described. This was a bit of a late reporting on a December 2008 paper by Varricchio et al., which I've not had a chance to go over yet. I might update this with more detailed information once I get the chance.

Finally, SV-POW has an interesting piece up on Brachiosaurus. I'd strongly suggest you read it. And, for kicks, I adapted Matt's image into something nice and widescreen-background sized:

I swear, I will post Higgs and the mouse post ...

Pulsars and Gravity

Posted by tigerhawkvok on March 14, 2009 02:56 in astronomy , news , IYA

Seeing as I mentioned gravity just a few days ago, while the Higgs boson is appropriate fodder, this "Perspectives" piece from Science magazine is a bit more topical.

In an effort to prove ever close to the ultimate answer, physicists and astronomers have been looking to probe gravity even deeper. The best results from orbiting pulsars agree with Einstein's theory of General Relativity to within 0.2%. Alternative models predict marginally, but measurably, different results with the most relativistic systems. The ultimate measure of relativistic gravity waves depend on orbital periods, eccentricity, and masses, so by seeking systems like these we can probe gravity even more deeply than we have already.

On the face of it, it may seem that 0.2% is good enough. 99.8% accurate will, in fact, get you to the Moon (in fact, that much error on your path amounts to a 1.74 km error in your landing site on a 384399 km trip). So why does it even matter? These alternative theories posit different fundamentals about the universe, including the necessity of dark matter and cosmic origin.

Pulsar schematic, via Wikipedia

Now, the most relativistic pulsar system we know of is PSR J0737-3039 — it has an orbital period of 2.4 hours, and an orbital decay of its semimajor axis of 7 mm/yr due to gravitational radiation in the form of gravity waves. Being a pulsar, it is an incredibly accurate clock, and enables measurements of such fine precision to be made, that we need to (and can!) measure the effects of its movement through the galaxy on its orbital decay. So, Deller et al. (DOI: 10.1126/science.1167969) show that using the VLBI and about a decade of observation can smash the possible GR error (or disprove GR at these precisions!) down to 0.01%.

Think about it. We're measuring something located ~600 parsecs away (1800 light-years [Lyr], give or take), measuring its orbital decay to millimeters to narrow constraints on one of the two most accurate theories in science to being "only" 99.99% accurate, up from 99.8%. Astronomy (and science in general) — bloody amazing.

By the way — I provide many links to scientific papers, in large part for rigor's sake, but if any readers (how many readers do I have? Do I have any?) are having difficulty, I'll see what I can do about finding free alternatives, such as arXiv.org preprints.

IYA Entry

Late Kepler Post

Posted by tigerhawkvok on March 10, 2009 20:16 in kepler , astronomy , news , research , IYA

So, I composed most of a post on the Kepler launch, then, well, forgot to post it. Belatedly, here we are:

So, Kepler. I mentioned it a little while ago, what was I talking about? Well, I was talking about the Kepler mission (kepler.gov) being sent up by NASA, set to launch on 3/6/09 (This is one of those "Whoops, posted late" parts).

Kepler is a sattelite that will observer one portion of the sky for its entire mission, looking for transit events. To understand a transit event, consider a lightbulb. When something passes in front of it, it obscures part of the surface from your view, and thus reduces the amount of light you observe. So, by observing the same starfield for its mission duration, Kepler can detect any minute changes in stellar flux, thus detecting a planet. The amount of flux change then gives you the planetary size (since color/spectral profile -> temperature -> size -> flux ).

However, there is a caveat here. Sunspots can often be regular, long lasting, or otherwise look like planets. So, my own impact on the Kepler project came with my research work with Gibor Basri, in which we wrote routines in IDL to analyze our own star for the influence of magnetograms on stellar luminosity profiles (IE, where are sunspots? How big? etc).

Various identification methods picking out
umbrae and penumbrae

A particularly good example can be seen in the figure to the left, where various versions of the algorithms pick out different features in a sunspot group. It is important to note that the differences are exaggerated -- the sun is very bright, so the "dark" spots are valued about 0.85 on an absolute scale. you can also see on the right an early version of the algorithm picking out by far most of the major solar features, including the harder-to-discern faculae, or unsually bright areas (which are, of course, very hard to observe in photos such as these).

Early feature identification

The detection and automation algorithms we developed were actually fairly robust and accurate, though CPU intensive (running through about 100 photos took about 3-4 hours on my now-deceased laptop Liz), though our funding ran out over here before I could complete an algorithm to reverse-construct a star from its magnetic profile. Thus, by also observing the long-range magnetic profile of the stars (particularly Sun-like stars) we can rule out some categories of false positives. Looking at some more "final" algorithm photos, you can see why this could be relevant:


light contrast

Solar feature identification with
later versions of the algorithm

If a dark spot such as that passed along the star, it is enough of a brightness dip that it could register as a false positive — that is to say, it could look very much like a planet. While prolonged observation is one way to get around this, feature identification is another way. And I had a part in it! Nifty!

More:

Updated: 3/13/09

IYA Entry

McCain sticking it to the anti-science man

Posted by tigerhawkvok on March 04, 2009 22:47 in politics , news , anti-science

On February 27th, McCain began posting "porkiest projects" on Twitter. He did so again on 3/02, 3/03, and 3/04 (only six on the 4th when I last looked). So these have got to be kinda nutty, right? Or, you know, 13/36 could be science related. How's this for a list?

  1. Apparently museums aren't public goods. Nor the building of produce jobs.
  2. Who needs them there sea turtles anyway. Not like species extirpation has ever caused environmental problems ...
  3. Lobster populations aren't shrinking. Really.
  4. Now, I think nuclear is the way to go, but apparently McCain really has something against solar power
  5. Along the lobster line — no need to keep up those pesky fish populations either.
  6. By the way, we never found out anything useful by studying other species' genetic profiles. Obviously funding that is dumb.
  7. Apparently he is just outright misinformed and doesn't know how problematic — and expensive — theft of copper wires actually is.
  8. By the way. Las Vegas is totally sustainable and uses only its own resources. Not like its a drain on three surrounding states at all.
  9. He really has a bone to pick with population genetics, huh?
  10. To channel Peter Griffin, though, it really grinds my gears when he dismisses astronomy right out.
  11. I suppose McCain never heard how beavers have massive ecosystem impacts, huh?
  12. Startling honey bee decline, anyone? Apparently he just has it out for flowering plants. Who needs angiosperms.
  13. While we're at it, lets just not have as nutrious or plentiful crop for our grazers. Really, genetics is the work of the devil.

Suddenly, I'm gladder I didn't vote for him. I really thought he was more pro-science than that.

Possible 22 year old confirmation of gravity waves

Posted by tigerhawkvok on March 04, 2009 17:18 in astronomy , news , IYA

Via Slashdot and the arXiv blog, it turns out that we may have actually detected gravity waves in 1987 associated with SN1987A.

OK, that was a bit of a rush. Let's unpack that a bit. Astrophysicists have been searching for gravity waves for a while now, which are linearized plane wave solutions to the Einstein Field Equations with two polarizations (the other fourteen dropping out). The key bit to this solution is that the coordinate positions of the particles remain constant for all τ, but the fractional change in distance between points A and B changes in an oscillatory manner (as 0.5a sin[ωt+δ] ). Since all but two polarizations drop out, this means that for a plane wave oriented in the z direction, wave effects are restricted to the orthogonal x,y plane.

LIGO

Modern interferometers use long arms with a laser cavity to measure very very small fractional changes in distance via destructive & constructive interference. However, before this, large aluminum cylinders with piezoelectric crystals arranged about it were constructed in an attempt to measure these gravity waves. When SN 1987A went off (Supernova 1987 A, as the first one in 1987), John Weber reported that he detected gravitational waves from the SN detonation. However, calculations of first-order effects (almost always the largest) showed that his detector was insufficiently sensitive to have found any gravitational waves.

However, a new paper (preprint) shows that asymmetries in the 1987 explosion could lead to an enhancement by a factor of 104 in SN1987A, putting these waves right in Weber's detectable range.

So, it seems in retrospect that Weber got the short end of the stick, all things considered. But it's definitely worth re-examining his data to see if he did, in fact, confirm gravity waves 22 years ago.

IYA Entry

Bush ESA midnight legislation suspended

Posted by tigerhawkvok on March 03, 2009 18:29 in biology , news

Via the EBV blog: Bush's midnight legislation that weakened the act by not requiring scientist input (via the US Fish and Wildlife service) before federal officials could say a species did not need protection. This was, in fact, serious enough that California sued to prevent this.

Formally speaking, Obama suspended the legislation to review "whether it promotes 'the purposes of the [Endangered Species Act]'". This is certainly good news, and good precedent, for requiring scientific review!

I had started a post on salamanders, but the spazzy laptop ended up killing it. Oh well. That post, and the others I mentioned, will be up soon enough. Perhaps if everything works out right, tomorrow will be a small photoblog. Meanwhile, I'll leave you with an interesting link, via Grrlscientist over at ScienceBlogs. Hint: What's the last color you'd expect to see on a dolphin?

Magnetic Monopoles

Posted by tigerhawkvok on February 26, 2009 17:33 in physics , news

OK, perhaps the title is a bit misleading. However, a Science paper published today (DOI: 10.1126/science.1167747) describes a method by which images of magnetic monopoles can be induced and measured, in full compliance with E&M. The trick? By taking advantage of the quantum Hall Effect, you can construct a system such that the boundary conditions can be constructed to break temporal (T) symmetry, allowing quantum mechanical topological effects.

By doing this around an insulating surface, and bringing a charged particle near it, a magnetic monopole image is induced as a mirror to the electric charge. Whew. The idea of this is a nice mathematical trick that can make solutions far simpler than they would normally be, if you reduce a system to a set of "image charges" that represent a more complex field.

Perhaps someone has noted that this appears to break Maxwell's equations. Namely , the divergence of B = 0 (∂μFνλ=0) according to Maxwell's Equations is maintained by the following:

As we started with the Maxwell's equation, which includes [del] B = 0, the magnetic flux integrated over a closed surface must vanish. We can check that this is the case by considering a closed surface—for example, a sphere with radius a—that encloses a topological insulator. The detailed calculation is presented in the supporting online material (17). Inside the closed surface, there is not only a image magnetic monopole charge, but also a line of magnetic charge density whose integral exactly cancels the point image magnetic monopole.

And thus everything ends up working out. Trippy. Even more to the point, this could be measured by a magnetic force microscope, with mathematical proof to show its contribution could be distinguished from other, more trivial considerations. Perhaps not the most pertinent discovery every, but still quite interesting to move the idea of a magnetic monopole out of pure speculation into something detectable.

Nature: Chixulub impact did not create global wildfires

Posted by tigerhawkvok on February 23, 2009 17:06 in dinosaurs , news , paleontology

An interested news update from Nature today: apparently, the K-T impact's (Chixulub event) [wiki, UCMP] global soot layer was not caused by vegetation, and was probably due to hydrocarbons. That is to say, the impact probably burned sequestered gas and oil.

Impact, artist rendition

The writing was on the wall for the vegetation idea for a few years, since 2003 studies showed a comparative lack of charcoal, which one would expect for global wildfires. This was supplemented by research done by Belcher et al in a PNAS paper showing that polycyclic aromatic hydrocarbons (PAHs) ratios match that of burnt hydrocarbons better than that of vegetation. So, no global wildfires. However, it *is* important to note that the massive amount of soot produced itself had a global environmental impact. No matter how you dice it, the K-T event was not a fun time to be around.

Enter Titanoboa

Posted by tigerhawkvok on February 07, 2009 15:45 in biology , news

A riddle: what happens when you cross a snake with a bus? Answer: A 13 m snake.

Scientists recently found Titanoboa, a 13 m boid from the Paleocene neotropical region (S America and S Asia). This thing was impressive; the animal probably had a 2m girth, weighed over a metric ton, and could eat a full-grown cow. As a member of Boidae, it was a full-on constrictor (which kind of begs the question of what it was constricting!)

Titanoboa

Probably the most interesting thing about it, though, is what scientists have done with the find. Using it, they have been able to estimate the neotropical region temperatures to be around 30-34 C (given the standard laundry list of assumptions). A Nature press release has more, with the primary article linked at the bottom (doi:10.1038/nature07671). Pharyngula has a research blogging post on it and some more pictures from the article.

I'm going to try to find time to read the paper — from what I understand, they just used a growth curve using modern snakes as a baseline, but I'm curious as to if they took into account some pythonine snakes can be facultatively endothermic (DOI: 10.1016/S0306-4565(02)00048-7 ). Granted, this has only been observed in pythonine snakes, but I wouldn't rule out convergency (though this has a high metabolic cost, this could considerably broaden the temperature range it could live in). I'd also be curious to see if oxygen isotopic analysis, such as done with theropod dinosaurs, can confirm internal thermoregulation (DOI: 10.1130/0091-7613(2000)28<799>2.0.CO;2).

That's it for now!

Update and Shell-less turtles

Posted by tigerhawkvok on November 29, 2008 20:59 in evolution , biology , news , paleontology

Hm, I've not blogged in a bit. Well, I'm working on the graduate school apps with a bit of a mix of physics, astrophysics, paleontology and biomechanics. Some dual applications, some single. We'll see how it plays out.

I've also finally submitted my paper to Proceedings B, and hopefully it will be accepted (or conditionally accepted).

Nah, the real trick is money. The economy sucks, finding a job has been hard, and well, not quite enough money to make rent. Ugh. Well, perhaps I'll blog on science tomorrow at the airport. In particular, Science and Nature have had a few interesting articles as of late, such as one on a new turtle find -- it has a plastron, but no upper shell -- and with teeth! Dubbed Odontochelys, it is placed phylogentically basal to all all extant and extinct testudines. While I find the use of "Ontology recapitulates phylogeny" a bit problematic, its still a very interesting read, and I feel that its sparing use in this context is justified.

Odontochelys

It seems I blogged on science accidentally anyway. Huh. Perhaps not much, but nevertheless.

The full paper can be found here: Nature.com (DOI: 10.1038/456450a , Reisz & Head ).

Update 03/15/09: Link repair

The LHC is on, and we're still here

Posted by tigerhawkvok on September 10, 2008 11:46 in physics , news , anti-science

So I was going to make a post about how the world hasn't ended, but you know, this time around, doomsayers can't even doomsay correctly.

That is to say, the Large Hadron Collider, or LHC, turned on today at 10:33 CET, and we're all still here. The test beam went in one direction (not the two necessary you know, for a collision) at less than full power, so doomsayers can't possibly have been correct. However, I think it might be worth listing off a few reasons why the LHC couldn't destroy the Earth:

  • You've got protons. Accelerated really fast. So if you make a black hole, its going to have a really tiny Schwarzschild radius, or the radius of the event horizon (Rs). Like, GMc-2 (to first order). Which is to say, at the speed these guys are traveling, a completely tangential approach would only decay into the black hole at < 1.5Rs. How big is Rs? Ballparking, we have
    (10-11)(10-26)/(1016)=10-43 m. That's really really tiny. And since black holes evaporate roughly as ħm-2, really small things evaporate really really really really fast — in this case, 1020 kg/s. This little mini black hole will need to get within 10-43 m of particles faster than it evaporates, which even at a hairs breadth below the speed of light it doesn't cut it. Really roughly, it'll last:
    10-17m3 s = 10-98 s, Which translates to a distance of under 10-90 m — virtually no distance at all, and an infinitesimal fraction of a nucleus. In fact, being a very small fraction of a Planck length, its virtually meaningless to say it traveled at all.
  • This is a bit more complicated by the fact that black holes have no hair but retain charge, so this will be a charged nearly light-speed traveling black hole. Very small correction, but there.
  • The strangelet hypothesis also won't happen. Sure, colliding strangelets with normal matter can convert normal matter into strange matter. But, cross-sections are again really tiny, and statistics ensures that the reaction would die out by decaying of the strangelet.
«Previous   1 2