holycrapscience!

Great Scientists Don't Need Math

Mon, 22 Apr 2013 09:07:36 -0400

Great Scientists Don't Need Math:

E.O. Wilson shares a secret: Discoveries emerge from ideas, not number-crunching.

via Elad Noor

Mechanism of crumb toughening in bread-like products by microwave reheating.

Thu, 18 Apr 2013 16:44:08 -0400

Mechanism of crumb toughening in bread-like products by microwave reheating.:

Always wanted to understand this!

Abstract

Comparing breads reheated in conventional and microwave ovens revealed that the latter considerably toughens the crumb texture when internal boiling is induced. Moisture loss in itself has a relatively minor toughening effect. The major changes, caused by boiling, occur only in systems with starch concentration in excess of a threshold level of about 37% (wet basis). Substantially greater amounts of amylose are leached out of the granules in the case of sustained boiling during microwave heating, as compared to conventional oven heating. The free amylose solution is being “pushed” by the generated steam pressure toward the air-cell wall interface. A rich amylose phase is accumulated at that interface and over the granules. Upon cooling, the amylose undergoes rapid phase changes; thus, toughening is apparent in a relatively short time after heating. Minimizing the textural deleterious effects in microwave reheating of bread-like products should entail (a) preventing or minimizing internal boiling, (b) diluting of the starch concentration below the threshold level, (c) interfering with the amylose phase change by using complex forming agents.

useitasfuel: For my scientific illustration class… succulents...

Fri, 29 Mar 2013 13:20:30 -0400

useitasfuel:

For my scientific illustration class… succulents are cool ass plants.

"In ants and bees, there are no sex chromosomes. Instead, sex is determined by whether or not an egg..."

Thu, 28 Mar 2013 16:40:07 -0400

“In ants and bees, there are no sex chromosomes. Instead, sex is determined by whether or not an egg was fertilized. If the egg isn’t fertilized, the offspring is male. If the egg is fertilized, it’s female. So male ants have no fathers, and they have half as many chromosomes as females. Poor little things.”

- Beatrice the Biologist: Clarification, Sex Determination, and Cheesecake

(via chopdawg)

I’ve always maintained that its not the number of chromosomes that matters, but rather how you use them.

(via jtotheizzoe)

Some (Quantitative) Thoughts on Housing and Homelessness in NYC

Wed, 27 Mar 2013 14:52:00 -0400

The other night I was speaking to a friend about the intersection of real estate warehousing (the practice of buying housing and keeping it unoccupied for investment reasons; see NYT article linked below) and homelessness. My friend claimed that there are more than enough vacant apartments to house all of the city’s homeless with the obvious implication that we should really do something about these warehousing practices.

I was curious, so I started searching around to answer a few questions, the most basic of which are these: How many vacant and unavailable apartments are there in NYC? How many homeless people are there?

Fortunately, the NYC Department of Housing Preservation and Development has a decently thorough and relatively recent report on their “Housing and Vacancy Survey” (link below) which gives us a good handle on the number of vacant units in NYC.

In 2011, the number of vacant available rental units was 68,000, while the number of vacant units available for sale was 31,000. At the same time, the number of vacant units not available for sale or rent was 164,000 in 2011, the highest since 1965, when the first HVS was conducted (Table 1). Of the 164,000 vacant units not available for sale or rent, 48,000 units, or 29.4 percent,were classified as unavailable because they were undergoing or awaiting renovation.

As previous HVSs have shown, most of these unitsundergoing or awaiting renovation will be occupied or vacant and available for sale or rent by 2014, when the next HVS will be conducted (Table 8). At the same time, the number of units that were unavailable because of occasional, seasonal, or recreational use was 65,000 or 39.5 percent, the highest since 1978, when the Census Bureau began classifying vacant unavailable units by such reason (Table 8). Of the units in this category, more than six in ten were located in Manhattan, and about six in ten were in cooperative or condominium buildings.

First of all, notice that not all of these units are being “warehoused” exactly - many of them are part-time homes for our great city’s globe-trotting wealthy (about 40%). Another ~30% are ostensibly undergoing renovation, which should mean that that they’ll hit the rental or purchase market in the near-ish future (one hopes). Nonetheless, I’m going to ignore these subtleties and push forward to think a little about the numbers.

According to the Coalition for the Homeless (link below) 164,000 units is about 3 times the number of homeless people in municipal shelters in NYC, which is about 50k people. I’m gonna to break here for a second just to let myself reflect on that number; 50,000 homeless people. Wow.

But note that this 50k number doesn’t include people who are in private shelters nor does it include people who are just on the streets. The same page from the Coalition for the Homeless claims that 90% of homeless people in NYC use the municipal shelter system, so the total number of homeless in NYC should be about 56,000. That’s a big number. It’s also about 1/3 the number of vacant but unavailable housing units in the city. If those units could house even 2 people on average, then 1/6 of the vacant but unavailable apartments could house all of the city’s homeless people.

Now we have to ask - how many of those unavailable apartments could realistically be made available through some policy measure. I suppose that depends on what you think can be accomplished through the political process. For example, is it realistic to envision a policy regime that would make the 65,000 units that are occupied on an occasional/partial basis available to renters? More than half of those units are in Manhattan’s cutthroat real-estate market. If they were made available, who would actually get them? Would dumping all these units onto the market open up room at the low end or would they all get sold off to the wealthy?

I don’t really know how to answer these questions, but I’ll throw out some numbers anyway. The citywide rental vacancy rate in NYC was about 3.1% in 2011 (the rate in Manhattan and Brooklyn is right now much lower at ~1.5%). If some utopian dream was realized and all the vacant units were somehow dumped onto the rental market, then the citywide rental vacancy rate would go to ~8.1% (there are about 3.3 million units in NYC total). I think it’s reasonable to assume that more-than-doubling the supply would have a big effect on rental prices. Because of the level of demand for NYC housing, it seems unlikely that these units would end up in the hands of the homeless without some serious policy changes, but perhaps a big decrease in housing pricing in NYC is good medicine regardless? My wallet certainly thinks so.

ADDENDUM:

Just want to make clear - I am not making a claim that homelessness is primarily an economic phenomenon. I was just checking up on a claim that my friend made, which is that there are far more vacant but unavailable housing units in NYC than there are homeless people. The claim, it turns out, is very true. Even if releasing all those units would do nothing for the homeless, I think that truth is focusing.

References:

NYT on Warehousing: http://www.nytimes.com/2005/12/25/realestate/25home.html
HPD Housing and Vacancy Report: http://www.nyc.gov/html/hpd/downloads/pdf/HPD-2011-HVS-Selected-Findings-Tables.pdf
Coalition for the Homeless, Basic Facts Page: http://www.coalitionforthehomeless.org/pages/basic-facts-about-homelessness-new-york-city-data-and-charts

nybg: Dickinson’s personal herbarium was a passion of hers,...

Fri, 01 Mar 2013 13:20:19 -0500

nybg:

Dickinson’s personal herbarium was a passion of hers, amounting to over 400 pressed specimens which she would often share in letters. It wasn’t that long ago that the NYBG had its own exhibition on the poet’s surprising knack for botany. —MN

thedelegatefromperu:

From Emily Dickinson’s journal, pressed plants and flowers, c. 1839-1846

nybg: Mutation is rarely a phenomenon that inspires admiration...

Thu, 28 Feb 2013 16:40:14 -0500

nybg:

Mutation is rarely a phenomenon that inspires admiration or high valuation, but in plants, the boundaries are a little more vague. Fasciation occurs when a plant—mutated by one of many possible factors (bacteria, viruses, insect attacks, simple genetic variation, etc.)—loses the plot a bit.

By that, I mean that the meristem stops directing the plant to grow new tissue around cylindrical points and instead shoots off in odd ribbons of tissue. And while this “ailment” isn’t quite as broadly prized as other botanical afflictions, such as striped tulips, there’s a definite horticultural element out there on the hunt for beautiful oddities.

That cactus up top is giving a thumbs up, so I suppose it’s all in good fun. —MN

propaedeuticist:

Fasciated Flora

scientificillustration: Icones Farlowianae by BioDivLibrary on...

Thu, 28 Feb 2013 13:20:28 -0500

scientificillustration:

Icones Farlowianae by BioDivLibrary on Flickr.

Cambridge, Mass. :The Farlow Library and Herbarium of Harvard University,1929..
biodiversitylibrary.org/page/36263198

medicalschool: Colorized SEM of Anthrax Bacteria

Wed, 27 Feb 2013 16:40:19 -0500

medicalschool:

Colorized SEM of Anthrax Bacteria

Slate: Golden Rice Retrospective

Wed, 27 Feb 2013 13:20:12 -0500

Slate: Golden Rice Retrospective:

On the occasion of the first commercial Golden Rice crop being planted in the Phillipines.

smithsonianmag: Photo of the Day: The Underground Lake - Reed...

Mon, 18 Feb 2013 16:40:32 -0500

smithsonianmag:

Photo of the Day: The Underground Lake - Reed Flute Cave in Guilin

Photo by: Christian Ortiz (San Jose, California); Guilin, China

dendroica: Photographer Scott Cromwell captured the...

Mon, 18 Feb 2013 13:20:21 -0500

dendroica:

Photographer Scott Cromwell captured the split-second moment when a chameleon went in for the kill. Mr Cromwell watched as Geoffrey, a 17-month-old chameleon released his tongue towards a mantis and hit it straight on. Picture: Scott Cromwell/Solent News & Photo Agency (via Pictures of the day: 7 February 2013 - Telegraph)

"The biological implications of the extremely low metabolic rates calculated for subsurface sediments..."

Sun, 17 Feb 2013 13:20:33 -0500

“The biological implications of the extremely low
metabolic rates calculated for subsurface sediments are
profound. A respiration rate of 10−4–10−3 fmol SO42−
cell−1 d−1 is equal to 10−23−10−24 mol SO42− cell−1 s−1. As
1 mol comprises 6 × 1023 ions (Avogadro’s number), the
sulphate reducers respire on average 1 sulphate ion per
cell per second. Well-known cellular functions such as
flagellar motility are not possible at such a metabolic
rate; the rotation of a single bacterial flagellum in E. coli
requires 1,200 protons per revolution or 104−105 protons
per second83, so at 1 sulphate ion per second, a single
revolution of a flagellum would last several minutes.
Without flagellar motility, bacteria can move randomly
by Brownian motion that in porous sediments has an
effective diffusion coefficient of 10−9 m2 s−1 (REF. 84).
Over 1 million years, such random motion will lead to
a mean displacement of only 6 metres (diffusion time,
t = π L2 / 4Ds, in which L is the mean displacement and
Ds is the effective diffusion coefficient of cells). For imper
meable, non-advective sediments, the lack of flagellar
propulsion thus appears to provide a strong barrier to
genetic exchange with the surface world by whole cells.”

- Really clever back of the envelope calculation from “Microbial life under extreme energy limitation” by Tori M. Hoehler and Bo Barker Jørgensen, showing that many bacteria (e.g. those living in energy-poor ocean sediments) don’t have have enough energy to move.

Via Elad Noor.

Reference: T. M. Hoehler, B. B. Jørgensen, Nature reviews. Microbiology 11, 83–94 (2013).

elegantbuffalo: Parallel Evolution: when similar...

Sat, 16 Feb 2013 16:40:15 -0500

elegantbuffalo:

Parallel Evolution: when similar characterisitcs arise in closely related organisms

Most people who have studied even a little evolutionary biology are aware of the marvelous diversity of the Lake Victoria cichlids. These fish have radiated to fill nearly all available niches in the lake. Over only a few million years, 300 species were developed from one ancestral populations.

What you may not know is that there are cichlids in Lake Malawi and Lake Tanganyika, too, and all originated from similar ancestral populations. What’s more, the cichlids in each of the three lakes have evolved to fill nearly the exact same niches. The correspondence in ecology and morphology between the fish of the three lakes is the most spectacular example of parallel evolution that I’ve seen. Take a look at this figure, where the fish on the left come from Lake Tanganyika and the ones on the right are from Lake Malawi.

kewl.

transportationnation: What’s underneath Grand Central Terminal:...

Fri, 15 Feb 2013 16:40:19 -0500

transportationnation:

What’s underneath Grand Central Terminal: well, right now, it includes a construction zone for the East Side Access project.

Check out more MTA pictures here. (Photos: Metropolitan Transportation Authority / Patrick Cashin)

cosmicinsignificance: Rafflesia arnoldii bud, one day before...

Fri, 15 Feb 2013 13:20:24 -0500

cosmicinsignificance:

Rafflesia arnoldii bud, one day before opening.

”Rafflesia arnoldii is the largest (single flower); its blossom attains a diameter of nearly a meter and can weigh up to 11 kg. Not only is it the world’s largest flower, it is one of the most bizarre and improbable organisms on the planet… The blossom is pollinated by flies attracted by its scent, which resembles that of carrion.”

ugh.

biomedicalephemera: Chelys fimbriata [now Chelus fimbriatus] -...

Thu, 14 Feb 2013 13:20:33 -0500

biomedicalephemera:

Chelys fimbriata [now Chelus fimbriatus] - Mata-mata

Some people say the Mata mata turtle looks like it’s smiling, because of its unusually-shaped mouth. The Indigenous South American nickname for the turtle, “matamata”, means “I kill”, according to Fritz Jurgen Obst. Whether that eponym meant that the turtle was good to kill and eat or the turtle killed a lot is unknown. The relatively large size and a meat quality similar to the Alligator Snapping Turtle makes the former meaning more probable.

In the wild, Chelus fimbriatus lives in stagnant waters, blackpools, and muddy streams around the Amazon rainforest. Its fringed neck and murky coloration, combined with algae that grows on its carapace, makes this turtle an excellent ambush hunter. When fish come near it, the mouth opens up, and the mata mata “vacuums” them in. This is in contrast to Alligator Snapping Turtles, which are similar ambush predators, but with a different strategy. The tongue of the snapping turtle acts as a lure, and unsuspecting fish swim right into its mouth.

Transactions of the Zoological Society of London, 1885.

Beautifully written paper with even nicer figures! (Here’s...

Wed, 13 Feb 2013 16:40:26 -0500

Beautifully written paper with even nicer figures! (Here’s a PDF)

Abstract

The emergence of Cetacea in the Paleogene represents one of the most profound macroevolutionary transitions within Mammalia. The move from a terrestrial habitat to a committed aquatic lifestyle engendered wholesale changes in anatomy, physiology, and behavior. The results of this remarkable transformation are extant whales that include the largest, biggest brained, fastest swimming, loudest, deepest diving mammals, some of which can detect prey with a sophisticated echolocation system (Odontoceti – toothed whales), and others that batch feed using racks of baleen (Mysticeti – baleen whales). A broad-scale reconstruction of the evolutionary remodeling that culminated in extant cetaceans has not yet been based on integration of genomic and paleontological information. Here, we ﬁrst place Cetacea relative to extant mammalian diversity, and assess the distribution of support among molecular datasets for relationships within Artiodactyla (even-toed ungulates, including Cetacea). We then merge trees derived from three large concatenations of molecular and fossil data to yield a composite hypothesis that encompasses many critical events in the evolutionary history of Cetacea. By combining diverse evidence, we infer a phylogenetic blueprint that outlines the stepwise evolutionary development of modern whales. This hypothesis represents a starting point for more detailed, comprehensive phylogenetic reconstructions in the future, and also highlights the synergistic interaction between modern (genomic) and traditional (morphological + paleontological) approaches that ultimately must be exploited to provide a rich understanding of evolutionary history across the entire tree of Life.

griseus:

Esquema que muestra la transición de un raoellido del Eoceno (A) hasta los cetáceos del Eoceno / Oligoceno (B-H).

En orden Indohyus (Raoellidae, A), Pakicetus (Pakicetidae; B), Ambulocetus (Ambulocetidae; C), Remingtonocetus (Remingtonocetidae, D), Georgiacetus (Protocetidae, E), Dorudon (Basilosauridae, F), Janjucetus (Janjucetidae, Mysticeti; G) , y Aetiocetus (Aetiocetidae, Mysticeti, H)

Las ilustraciones están por Carl Buell. Paper en Science direct

Richard Lenski is a gentleman and a scholar

Wed, 13 Feb 2013 13:20:16 -0500

Richard Lenski is a gentleman and a scholar:

And a fantastic editor. That is all.

astronomy-to-zoology: Mekong Giant Catfish (Pangasianodon...

Sat, 09 Feb 2013 16:40:30 -0500

astronomy-to-zoology:

Mekong Giant Catfish (Pangasianodon gigas)

is a enormous species of shark catfish native to the Mekong basin of Southeast Asia. While physically this species looks similar to other catfish the size that this animal can obtain is amazing with individuals recorded growing up to 10 feet long. Making them the largest freshwater fish alive today. Despite their amazing size this species is critically endangered with most of their native range dammed, and over fishing taking a toll on their population size.

Phylogeny

Animalia-Chordata-Actinopterygii-Siluriformes-Pangasiidae-Pangasianodon-gigas

Image Sources: 1, 2