My Geek Pride is hurt: BLOSUM matrices

BLOSUM (BLOcks of Amino Acid SUbstitution Matrix) are the canonical substitution matrices used for scoring protein sequence alignments. In essence, it calculates the relative frequencies of all aminoacids in each position within an alignment and assigned a probability to the substitution of a particular residue. BLOSUM matrices built with closely related sequences are more stringent and have high numbers (BLOSUM80) indicating the percentage similarity allowed to include a sequence in the matrix (in the latter case, all proteins share at least 80% sequence identity).

BLOSUM matrices were developed in 1992 by Henikoff and Henikoff and since then have been extensively used in all analyses involving protein sequences...

and then, here comes he "AAARRGHHHH!!!"

Styczynski et al (2008) were killing their time looking at the evolution of the BLOCKS database and found the unthinkable.... an error in the source code for the algorithm that calculates de BLOSUM matrices!!!! that means... the results obtained with the available BLOSUM matrices differ significantly from the expected algorithm from Henikoff & Henikoff... merde!

Weirdest thing of all.. when corrected and tested back for the use of the matrices in database sequence search, it turned out that the "wrong" matrices performed much better in retrieving protein homologs than the "corrected" matrices.

Fortunately, it seems that though the difference is statistically significative, it is not big. That means, we haven't fucked it up so bad.

Epilogue to the blosum...

1) 16 years of extensive usage doesn't mean it is RIGHT.

2) how come that no one, ever, in 16 years, ever noticed this difference!!! THAT is what happens with dogma... when you take anything from granted

3) messing things up is not always THAT bad...

4) I didn't understand from the article if they proposed that the matrices were corrected even if they performed worse...

5) I would expect to see a huge ocean of erratas everywhere because "when using the revised blosum matrices... our results from the past ten years have completely changed!!"

Bound to...

Diving into my ipod, I rediscovered what I think is one of the best breaking up songs ever. I'm not in that mood now, but I keep recognizing it. So, this post goes dedicated to all those girls that actually are brave enough to say 'I'm through'... I mean, there must be some!


"I've thought about it for a while
and I've thought about that many miles
but I think it's time that I've gone away

The feelings that you had for me
have gone away it's plain to see
and it looks to me
that you're pulling away

I'm gonna pick it up
I'm gonna pick it up today
I'm bound to pack it up
I'm bound to pack it up
and go away

I found it hard to say to you
that this is what I have to do
but there is no way that I'm gonna stay

there are someone many things
you need to know
and I wanna tell you before I go
but it's hard to think of just what to say

I'm gonna pick it up
I'm gonna pick it up today
I'm bound to pack it up
I'm bound to pack it up
and go away

I'm sorry to leave you all alone
you're sitting silent by the phone
but we've always known there would come a day

The bus is warm and softly lit
and a hundred people are ridin' it
I guess I'm just another running away

I'm gonna pick it up
I'm gonna pick it up today
I'm bound to pack it up
I'm bound to pack it up
and go away

Oh yeah, yeah"

The White Stripes, De Stijl...

Lotharingie... la breve

"Uno cree que siempre ha sido así, pero no... no todo lo es todo. Aquello era vastísimo, y aunque no todos se asumían como francos, la dominancia carolingia era indiscutible. Siempre había sucedido así, los grandes imperios se resquebrajaban hasta minúsculos territorios. Así pasó con Cárthago, el Senatus Populusque Romanus de Trajan, el Khanato de Ögedei y el Califato Umyyad... así pasaría después con la dinastía Qing, la Totius Hispaniae de los Habsburgo, el Imperio Napoleónico, el Brazil de Braganza y la Soyuz Sovetskikh... así pasará con la Rossiyskaya transcontinental, la Francia de Ultramar, el paternalismo neocolonialista de la Norteamérica intervencionista y el mayor imperio en tiempo y extensión: el United Kingdom del imperio británico.

El entonces imperio franco de Charlemagne había sido dividido por primera vez burdamente por Louis I (el primero de una veintena de luises hasta ahora) en imperios del Este y del Oeste. Lothair llevaba ya diez años defendiendo ferozmente su derecho legítimo sobre los territorios Francos. La última guerra civil (que entonces respondía a un pleito entre hermanos) culminó esa noche del 843 con el Tratado de Verodunum. Esa noche a la orilla del Meuse Lothair recordaba la figura de su abuelo, aún abatido al fondo del valle por el Juramento de Strazburg. Así nacía la Lotaringia, Lotharii regnum, bajo la tradicion divisionista hereditaria de los carolingios.

La Lotharingie sería recordada como el reino entre el Rhin y el Rhône, aunque más adecuado sería medirla entre la costa frisa del Mar del Norte a Roma. Así, con esa división entre el imperio Franco del Este y del Oeste, la Lotharingie iniciaría una larga disputa entre francos y alemanes que parece terminar apenas en la segunda mitad del siglo XX. Además resultaba ser el primer reino que no recibía su nombre del idioma que hablaban sus pobladores (Francs, Alemanii) puesto que comprendía un amalgama cultural y linguístico.

La duración del magno reino lotaringio fue ridículamente corto. Una del 855 presenciamos cómo el gran Lothair ha abdicado a la corona lotaringia para recluírse en la abadía de Prüm. Poco antes de tomar los votos, repartió el reino entre sus tres hijos. La Lotharingie queda reducida de la Frisia a la Suiza, bajo el reinado de Lothair II. Ésta divisón tampoco duraría mucho. Lothair moriría ese mismo año, Lothair II moriría en 869 sin herederos legítimos, lo que conduciría a la repartición territorial entre los hermanos de Lothair I y la consecuente desaparición del reino de Lotharingie con el Tratado de Meerssen... aunque en realidad el territorio norte se encontraba ya bajo el control vikingo danés."

La región es interesante...

más que nada, la aparición y desaparción de Las Cosas Importantísimas me recuerda también la historia de Plasmogenia... y no sin cierto temor me parece que la genómica le da un aire...

insisto, no todo lo es todo

La tektonik

One of the weirdest things I saw in France... a "new" dance style á lá techno-pop that reminds me a LOT of the early 90's... the rediscovery of Michael Jackson's Moonwalker maybe? if fashion has already made a complete turn and rap/dance/moonwalker is cool again... maybe we have a tiny hope of seeing a grunge retro-moment soon?


I find it good for gymnastics... and I think it's cool to see such self-assurance in teens!

Del lado de allà...

Paris nos recibio frio y obscuro. El periferico parisino resulta menos feo pero igual de tedioso para perderse. Aunque se recorre en menos tiempo.

El frio pues total. Bueno, no tanto pero para mi termostato mexica si es demasiado. Frio todo el tiempo, solo se diferencia entre "mucho", "menos" e "intolerable". Y yo sin kleenex no puedo vivir, o al menos no sin manchar de verde clarito mi bufanda. Lo cual tampoco conviene porque despues de un rato la humedad en la bufanda se pone fria tambien. En la calle no hay nadie pero las tiendas (como la fnac por ejemplo) estan atascadas. No es como para irse de compras ni tomarse el cafe-cliché frances, porque se te pueden ir 11 euros en una sentada de cuatro chocolates calientes. !Pero lo valen en el frio!

Nota cultural sobre mi propia ignorancia: existe una diferencia entre le givre y la neige, aunque el resultado es el mismo (casi): todo se ve blanco. El primero dîcese del hielo que se encuentra TODAS las manianas sobre toda superficie congelable, el segundo es la nieve que se forma exclusivamente cuando llueve a 0°C... que por cierto no he visto aun. Todos los autos se congelan en la noche y yo soy el unico en toda Nancy que se maravilla de ello y que disfruta sin bufar (gesto predominantemente frances para expresar disgusto ligero pero incomodo) quitar con la palita de quitar hielo (porque aqui hay una cosa especial para todo) (y que Marie no tiene y por eso usa su tarjeta de credito) (bueno, quien sabe si es la suya). Asimismo, soy el unico que se detiene a tomar fotos de las fuentes congeladas (metaarte cronologico involuntario), las flores muertas por la helada, las bancas bajo el hielo y las ventanas fractalicas (y unas cacas congeladas que no me dejaron fotografiar y que de hecho lalo me habia comentado) y que se detiene a descifrar el origen etnico de cada no-blanco que se cruza en la calle.

Para fumar, hace falta ser un adicto erizo nicotinico pero no friolento, porque sacar los dedos de los guantes es toda una hazania y no se puede fumar mas que en los cafes, los bares y las tabaquerias (y solo hasta el 1° de enero). Como dijo Serguei en NY: "either you drink or either you smoke, because you can't smoke indoors but you can't drink outdoors". De todos modos, pague mis 4.60 € para comprar mis Gauloises brunes-sans-filtre à la Cortâzar.

Finalmente, el tren ES la onda (mas que la Taq! aunque igual de caro), asi que unas mentadas de madre a Ernesto Zedillo por vender los Trenes Mexicanos. Nos quito el romanticismo de viajar en bola, viendo paisajes bonitos y con la oportunidad de ligar chicas guapas. Yo, encontre mi francesa.

To Metagenome or not to Metagenome

A masterpiece of science blogging was posted here (http://suicyte.wordpress.com/2007/11/20/smallest-primate-ever-discovered/), addressing the finding of primate sequences in the GOS dataset, just one of the unassesed ambiguities in metagenomics.

The post is beautifully written and made me laugh really loud. The point is that metagenomics is sometimes being overselled just in the very same way as genomics has been (see Eisen's blog for just some examples) and this leads to an skeptic counterwave.

My brief cons and pros:

a) metagenomics offers indeed the unprecedented opportunity to explore unculturable microbial diversity, which no other tool can do.

b) metagenomics is not only a technological advance like genomics was, it fits perfectly in an ecological (community/ecosystemic) theoretical background

c) no matter what everybody says, the GOS sampling has provided an incredible amount of data on previously unknown (and often unimagined) microbial diversity

d) criticisms on the amount of money spent on metagenomics seem to me like questioning the financial support on Humboldt's (or any other naturalist) voyages, which were explorative and not precisely focused on any hypothesis.

e) metagenomics is obviously error-prone, and it's biases have been poorly evaluated

f) metagenomics is much more useful in small, simple communities where a reasonable coverage can be achieved

g) metagenomics is much more useful in well known, deeply studied natural communities where it is employed to answer specific biological questions

h) metagenomics is expensive!

i) a great deal of work is still to be done on: defining parameters for comparing different samples, assessing taxonomical and functional biases, increasing assembly effectiveness and contig construction, improving functional prediction, developing tools for the analysis of such huge datasets, etc.

j) metagenomics is best when interdisciplinary, that is when it's used along with techniques and analyses from other disciplines that might provide physiological, evolutionary or ecological information

That being said, metagenomics rocks!

Rusch DB, Halpern AL, Sutton G, Heidelberg KB, Williamson S, Yooseph S, Wu D, Eisen JA, Hoffman JM, Remington K, Beeson K, Tran B, Smith H, Baden-Tillson H, Stewart C, Thorpe J, Freeman J, Andrews-Pfannkoch C, Venter JE, Li K, Kravitz S, Heidelberg JF, Utterback T, Rogers YH, Falcón LI, Souza V, Bonilla-Rosso G, Eguiarte LE, Karl DM, Sathyendranath S, Platt T, Bermingham E, Gallardo V, Tamayo-Castillo G, Ferrari MR, Strausberg RL, Nealson K, Friedman R, Frazier M, & Venter JC (2007). The Sorcerer II Global Ocean Sampling expedition: northwest Atlantic through eastern tropical Pacific. PLoS biology, 5 (3) PMID: 17355176

Dia de Muertos / Day of the Dead

More Day of The Dead Photos Here!




Encore, and late again, I'm posting on the Day of the Dead: an ancient mexican tradition from precolombine ages that was eventually merged by the spaniard priests with All Saints festivity. It is a very eclectic tradition with mexica and catholic elements. The original idea was to host all your deceased relatives at home on a specific day (originally in march, nowadays in November 1st and 2nd). They come back from Mictlán (the land of the dead) to visit and regain energies to continue their long journey towards their final home.

It is a festivity, a respectful party where you share and enjoy with your deceased relatives while mourning and remembering them. An altar is usually set up containing several elments: cempasúchitl flowers whose scent shall guide the dead towards home; copal (copalli is the nahuatl word for incense, product of the resins of the tree Bursera bipinata lay to burn) to cleanse the room; yolk bread of dead to feed your host; water to ease their thirst; salt for purification; chairs and a petate (knit mat of palm leaves) where they can lay to rest overnight; and candles.

A set of little skulls made of sugar simbolizing a tzompantli (skull altar of glory) with the names of the deceased written of the forefront, mixed up with skulls with skulls with the name of the living relatives on their forefront are an amusing and humble reminder of the thin distinction between life and death. All the altar is adorned with thin purple (catholic color for mourning) and orange (mexica color for mouring) papers cut with death alusions.

Finally, you can't forget to include the personal belongings of your deads, which function as evidence that you stil remember your dead and also to let them use them again and remember how their life was. You also cook mole (a complex dish used in important festivities) and whatever your deceased might have liked the most, along with cigarrettes and mezcal (distilled alcoholic beverage from Agave) to party, fruits as the product of the Earth (mandarin/clementine and sugarcane) and guava, tejocote and pumpkin candy.


These are some pictures from the megaaltars set up at Zocalo (Mexico City's central plaza) and at UNAM (our OpenAccess National University hehe) and... click here for last year's entry (nothing new, just different pictures), and more photos here and here inside my picasa web albums...

Fallece la Dra. Anita Hoffman

"Mexican Pioneer Arachnologist and Acarologist Dr. Anita Hoffman deceased"

El pasado 11 de octubre la comunidad científica sufrió una dolorosa pérdida al fallecer la Dra. Anita Hoffman, una de las más grandes figuras pioneras de la biología en México. La Dra. Hoffman dedicó su vida al estudio de arácnidos, posicionando el Laboratorio de Acarología de la Facultad de Ciencias de la UNAM (que lleva su nombre) como punta en el estudio de arácnidos. Por si fuera poco, la Dra. Hoffman formó a una gran parte de acarólogos y entomólogos de hoy, y produjo al menos dos libros de difusión en la Colección La Ciencia Desde México: "El Maravilloso Mundo de los Arácnidos" y "Animales Desconocidos: Relatos Acarológicos".
Tuve la oportunidad de conocer a la Dra. Hoffman durante una breve estancia que realicé hace ya una eternidad trabajando con ácaros acuáticos con mi maestro y amigo el Dr. Gerardo Rivas. Era admirable verla llegar con sus ochentaytantos al tercer piso de la facultad todavía con energía suficiente para regañar a varios. Y tras no se cuantos años de ser acaróloga, me tocó verla un día frente a una pecerita convertida en terrario mirando unos trombídidos medio fascinada. Digo, no me quedé en acarología pero sí le agarré gusto a los acaritos... que para saber un poquito más de ellos se puede consultar la página del Lab. Acarología Anita Hoffman y sus fotos ó la Colección Nacional de Ácaros en el Instituto de Biología de la UNAM.
La pérdida de la Dra. Hoffman representa icónicamente el fin de una etapa, tanto para la ciencia mexicana como para mí. Que esta breve entrada sirva como muestra de respeto a Anita Hoffman como aracnóloga pionera en México.

Two major recommendations

For all scientific-embedded procrastinators, two major links you should definitively check [mmmhh.. sounds like an infomercial] Thanks to LD Maldonado for these!

(ONE)
It's Doug Zongker's presentation of one of his most famous works in the AAAS sessions... It's only 4 min long and worth it!
Should you feel like reviewing his paper for further comprehension, you can find it linked here.



(I would need the hands of all my 35-members lab to count the number of presentations I've seen with less content)

(TWO)
An excellent piece of work on one of the most fascinating and often overlooked animals. Click to open[And makes me wonder how much of a prefabricated production pipeline nowadays science really is]

Useful windows

Hehe... Well, I finally found the only hardware where windows can be acknowledged as useful... y'don't believe me? belive the Lee, or this documentary, or that Gates guy at Windows 98 presentation... or those scuba divers from Sun... eh? oh yea, Windows is for graphics... suuuure! and besides bluescreens are in the past! check new WindowsVista!!!

nah... windows sucks, just go Linux!



Original idea and actual performance courtesy of The Dude, but I took the picture!
Tomorrow I'll try to come up with something against Mac... now jus lessgo bowlin'....

The "breaking-up" loop...

...or the neverending story...

courtesy of exquisite Mr. Tona (damn!)...



hehehe...

I'm brave enough to post it because I've broken the loop!!!!

enjoy....

Merci!

Pues en la nostalgia irapuatense situada apenitas entre la soledad del lab molecular y la nada (o la milpa para ser específicos) le entran ganas de agradecer a uno... se les extraña pero no tanto!
aún así, gracias por los paros de docencia. Que quieren, me enternece ver a edgardo a medianoche de sábado preparando la clase de recombinación para mis pupilos, así que gracias a:

Ana, Esme, Reni, Edgardo, Jules, More, Eria, Valeria y Andrea

y muchas también a Fred...

!gracias por aportar a la esquizofrenia del grupo 5081!

Saludos Irapuatenses

Le azoté...

Fred!!!! tu me manques!!!
un chingo!!!!
ya ven!!!!

Cuatrocienegas de Carranza

Well, after a mail from Jeff about Cuatrocienegas, I thought of finally writing about it here...

So, briefly Cuatrocienegas de Carranza is a small town at the middle of Cuatrocienegas Basin in the northernmost part of Mexico, inside Coahuila state. It was the homeland of Don Venustiano Carranza, a figure from the revolution famous for being president, almost achieving Veracruz independence and the killing of Emiliano Zapata.

Cuatrocienegas' Basin host one of the most hostile and attractive environment I've ever encountered. Its summer temperature can be as high as 52 C, and as low as -5 C in the winter. It is dominated by an haloxerophytic environment. Annual precipitation is less than 120 cc. Half of it is gypsum rock rich while the other half is calcite rich. It hosts many endemic species, including a cilindropuntia cactus and a desert turtle. Arguably, its main atraction is the system of surface water bodies called Pozas, that seem to date back to when pangaea opened and gave place to Tethys Sea. Hence, a strange diversity can be found: they're the home of desert fishes
which are more similar to marine fishes than to freshwater ones. They also present one of the most ancient and fascinating organisms in the world: microbialites or microbial mats and stromatolites, complex and fully functional ecosystems dominated by bacteria and archaea that deposit calcium carbonate and gypsum, giving rise to hard bodies.

Here some photos of the last field trip:
the not-so-portable molecular lab at the kitchen...









The Eguiarte-Souza Lab sunsetting at the dunes






Twin Ponds' contrasting colours, nearby Pozas Azules...


Dune, sky and cloud from Gypsum Dunes...




Such a strange bunch of people woould only meet at a strange place... Jeiry from Biotechnology Institute, Rafael from UNAM's filmothequem Eugenia and Fernando from Argentina, Me from nowherespecial and Vero from Chile... all at the Gypsum Quarry..


Filming sampling at Rio Mezquites' lunar red ponds...

My Life as something else: BACALAR

Well, continuing our trip, we stayed in Chetumal, a city whit a beautiful seashore and nothing else. I expected to see a friend there but couldn't reach her. (Bety? tuve allá y no te localicé)

We sampled in Laguna Bacalar, one of the very few permanent surface water systems in the Peninsula. With shallow waters and muddy bottoms, it is supposed to have seven diferent colours, each from a different cenote whose waters fed the lagoon. Place is just great. Period.We also sampled the (one and only) Cenote Azul, whose mouth is communicated with Bacalar. The colour is fantastic and it's more than 40 mts deep.
Some samples of what the team found: aquatic mites (I shall post on them somewhen), this is something like a huge Eylais,
we also found an amplypygii, an order of arachnids also known as "tailless whip scorpions" by anglophonics, and as "heart-spiders" or "tendarapos" by us.

and finally... an onychophor!!! from phylum Onychophora (bearing nails), also knwon as "velvet worms" or "spitting worms" because they secrete a glue from a specialized gland close to their heads. They're very rare to find and extremely poorly studied (nobody would accept a thesis on them here) this is my second most favorite animal in the world... from a time between annelids and arthropods. I'm so excited about this! I'll post a video soon. In the meantime, a link to wikipedia

My life as something else... CALAKMUL

Se murió La Suzy.
La perra más educada que he conocido, iba a la universidad y esperaba afuera. Un abrazo, Conz...

Report log from expedition to Mayan world: we made our first official stop in Calakmul (two close bumps), (More info here). I'm with the acarii team (in image from left to right): Gris, in charge of the National Colection of Acarii in the Biology Institute of UNAM; me; Marcia who was Gerardo's student at reproductive biology of Arrenuridae; and Ric who's looking for ectoparasites of scorpions and reptiles. Two more are missing: Dr. Rivas (latin expert on water mites) who did not climbed the pyramid and baby boy David, who took the picture.

The road was dominated by yellow butterflies in reproductive period (over 50 km!)... des papillon de fleur en fleur, d'amour... we crossed a basilisc (even when I find them adorable, I do not trust those biped reptiles) and some blue turkeys. We saw an encounter between a pack of spider-monkeys and wailing-monkeys... and a female wailer put her baby wailer on her back to protect him!!! I also saw an "ocofaisán" but were unable to photograph it. The natural protected area is just great, a paradise for any biologist!!!

Calakmul is one of the biggest mesoamerican ancient cities and nowadays it is also the name of a natural protected area. It's located right on the border between the northern and southern mayan zones. The city has been devoured by the forest, and the canopy is wonderfully appreciated from one of the buildings. The server is not allowing me to upload any more photos, but as soon as I get a chance I'll post them. We also went to Chetumal, Bacalar Lagoon, Tulum, Akumal, Puerto Aventuras, Playa del Carmen, Puerto Morelos and the botanical garden of ECOSUR, where we'll be doing a nocturn sampling visit tonight... I gotta run!!!

ulk isnt api issing er beloved... and thanks for the hat!!!

apendix city

Pues el viernes visité un hospital por probable apendicitis... pero "felizmente", "sólo" tengo gastroenteritis grave... estrenando antibióticos y tragando atole de arroz sin leche ni azúcar...

resulté más visceral de lo que creía...

OpenAccess, AIDS and Interactive Review

Phew! evaluations are finally over and... I survived!

So to all: PLoS ONE is a new peer-reviewed OpenAccess online publication innovating in the post-review process... meaning that:

1) y' get it for FREE
2) information and data is public
3) y' can actually participate in reviewing the paper!!!

more information 'bout PLoS ONE in its website PLoS ONE (obviously), 'bout open access here defined and in PLoS' OpenAccess website and which I can republish here under Creative Commons License, and in Jonathan Eisen's (the OpenAccess Cruzader) blog:

An Open Access Publication^[1] is one that meets the following two conditions:

1. The author(s) and copyright holder(s) grant(s) to all users a free, irrevocable, worldwide, perpetual right of access to, and a license to copy, use, distribute, transmit and display the work publicly and to make and distribute derivative works, in any digital medium for any responsible purpose, subject to proper attribution of authorship,^[2] as well as the right to make small numbers of printed copies for their personal use.
2. A complete version of the work and all supplemental materials, including a copy of the permission as stated above, in a suitable standard electronic format is deposited immediately upon initial publication in at least one online repository that is supported by an academic institution, scholarly society, government agency, or other well-established organization that seeks to enable open access, unrestricted distribution, interoperability, and long-term archiving (for the biomedical sciences, PubMed Central is such a repository).

^[1] Open access is a property of individual works, not necessarily journals or publishers.

^[2] Community standards, rather than copyright law, will continue to provide the mechanism for enforcement of proper attribution and responsible use of the published work, as they do now.

Hence, PLoS ONE is like a Peer-Reviewed Journal with all the benefits of OpenAccess PLUS a Blog-Like post-publication Interactive Review Process. So, everyone with a background on whatever-each-paper-is-about should check in and contribute to the post-publication review. All y'need is to visit PLoS ONE homepage, register (y'only need to identify yourself nonambiguously and your email account) and write!

Here, just to tease you, I leave this just-published paper published by John R. Talbott from Africans Against Aids which might generate the need of opinion in many of you:

---------------------------------------------------------------------------------------------------------------------------------

Size Matters: The Number of Prostitutes and the Global HIV/AIDS Pandemic

John R. Talbott^*

Africans Against Aids, Inc., New York, New York, United States of America

Background

HIV/AIDS prevalence rates across countries of the world vary more than 500-fold from .06% in Hungary to 33.4% in Swaziland. One of the most cited research papers in the field, utilizing cross country regression analysis to analyze other correlates with this HIV prevalence data, is flawed in that it weights each country's results by the country's population.

Methodology/Principal Findings

Based on cross-country linear and multiple regressions using newly gathered data from UNAIDS, the number of female commercial sex workers as a percentage of the female adult population is robustly positively correlated with countrywide HIV/AIDS prevalence levels. Confirming earlier studies, female illiteracy levels, gender illiteracy differences and income inequality within countries are also significantly positively correlated with HIV/AIDS levels. Muslims as a percentage of the population, itself highly correlated with country circumcision rates and previously found to be negatively correlated with HIV/AIDS prevalence, is insignificant when the percentage of commercial sex workers in a population is included in the analysis.

Conclusions/Significance

This paper provides strong evidence that when conducted properly, cross country regression data does not support the theory that male circumcision is the key to slowing the AIDS epidemic. Rather, it is the number of infected prostitutes in a country that is highly significant and robust in explaining HIV prevalence levels across countries. An explanation is offered for why Africa has been hit the hardest by the AIDS pandemic and why there appears to be very little correlation between HIV/AIDS infection rates and country wealth.

Difusión del Superenrrollamiento

Pues nada más haciéndole propaganda a Edgardo otra vez: su explicación del superenrrollamiento del DNA en su blog labjournal es simplemente estupenda. Quién lo iba a saber, antes cuando estudiábamos juntos no explicaba tan bien las cosas, me cae!

caminos de michoacán...

Un símbolo muy claro de lo que siento que le está sucediendo a este país... naturalito, así en una pared linda pero inútil de Pátzcuaro


Y en contra de mi propia incredulidad... resulta que sí hay campo de trabajo para los que estudian en la renombrada escuela guayaba que posteé más abajo... el único inconveniente es que hay que mudarse a Pátzcuaro...


tengo un buen de fotos más en el picasa... si les interesa