5,708 research outputs found
Telomere length and genetic anticipation in lynch syndrome
Telomere length variation has been associated with increased risk of several types of tumors, and telomere shortening, with genetic anticipation in a number of genetic diseases including hereditary cancer syndromes. No conclusive studies have been performed for Lynch syndrome, a hereditary colorectal cancer syndrome caused by germline mutations in the DNA mismatch repair genes. Here we evaluate telomere length in Lynch syndrome, both as a cancer risk factor and as a mechanism associated with anticipation in the age of cancer onset observed in successive generations of Lynch syndrome families. Leukocyte telomere length was measured in 244 mismatch repair gene mutation carriers from 96 Lynch syndrome families and in 234 controls using a monochrome multiplex quantitative PCR method. Cancer-affected mutation carriers showed significantly shorter telomeres than cancer-free mutation carriers. In addition, cancer-affected carriers showed the most pronounced shortening of telomere length with age, compared with unaffected carriers. The anticipation in the age of cancer onset observed in successive generations was not associated with telomere shortening, although, interestingly, all mother-son pairs showed telomere shortening. In conclusion, cancer-affected mismatch repair gene mutation carriers have distinct telomere-length pattern and dynamics. However, anticipation in the age of onset is not explained by telomere shortening. Pending further study, our findings suggest that telomere attrition might explain the previously reported dependence of cancer risk on the parent-of-origin of mismatch repair gene mutations
Crafting urban equality through grassroots critical pedagogies: weave, sentipensar, mobilize, reverberate, emancipate
How do ordinary citizens, activists and urban practitioners learn to become agents of change for a socially just habitat? The paper explores this question through the experiences of eight grassroots schools of popular urbanism working under the umbrella of the Habitat International Coalition (HIC) in Latin America. Building on a process of self-documentation and collective pedagogic reflection driven by the protagonists of these schools, the analysis explores the core pedagogic practices identified across the schools to enact popular urbanism as a collective and intentional praxis: to weave, sentipensar, mobilize, reverberate and emancipate. We argue that, put in motion, these pedagogic practices transgress the rules and boundaries of the formal classroom, taking participants to and through other sites and modes of learning that host significant potential to stimulate collectivizing and alternative ways of seeking change towards urban equality
Considering Intra-individual Genetic Heterogeneity to Understand Biodiversity
In this chapter, I am concerned with the concept of Intra-individual Genetic Hetereogeneity (IGH) and its potential influence on biodiversity estimates. Definitions of biological individuality are often indirectly dependent on genetic sampling -and vice versa. Genetic sampling typically focuses on a particular locus or set of loci, found in the the mitochondrial, chloroplast or nuclear genome. If ecological function or evolutionary individuality can be defined on the level of multiple divergent genomes, as I shall argue is the case in IGH, our current genetic sampling strategies and analytic approaches may miss out on relevant biodiversity. Now that more and more examples of IGH are available, it is becoming possible to investigate the positive and negative effects of IGH on the functioning and evolution of multicellular individuals more systematically. I consider some examples and argue that studying diversity through the lens of IGH facilitates thinking not in terms of units, but in terms of interactions between biological entities. This, in turn, enables a fresh take on the ecological and evolutionary significance of biological diversity
Non-L\'evy mobility patterns of Mexican Me'Phaa peasants searching for fuelwood
We measured mobility patterns that describe walking trajectories of
individual Me'Phaa peasants searching and collecting fuelwood in the forests of
"La Monta\~na de Guerrero" in Mexico. These one-day excursions typically follow
a mixed pattern of nearly-constant steps when individuals displace from their
homes towards potential collecting sites and a mixed pattern of steps of
different lengths when actually searching for fallen wood in the forest.
Displacements in the searching phase seem not to be compatible with L\'evy
flights described by power-laws with optimal scaling exponents. These findings
however can be interpreted in the light of deterministic searching on heavily
degraded landscapes where the interaction of the individuals with their scarce
environment produces alternative searching strategies than the expected L\'evy
flights. These results have important implications for future management and
restoration of degraded forests and the improvement of the ecological services
they may provide to their inhabitants.Comment: 15 pages, 4 figures. First version submitted to Human Ecology. The
final publication will be available at http://www.springerlink.co
INFECCIONES OPORTUNISTAS PRESENTES EN INDIVIDUOS CON VIH/SIDA: VIRUS DEL HERPES SIMPLE TIPO 1 Y 2, CITOMEGALOVIRUS Y HERPESVIRUS TIPO 8 ASOCIADO A SARCOMA DE KAPOSI
Las enfermedades oportunistas abarcan un conjunto de patologías que, como su nombre lo indica, aprovechan "oportunamente" la disminución en la calidad de respuesta del sistema inmune de los pacientes VIH-1 positivos para proliferar en el organismo. En muchos casos, se trata de enfermedades que no aparecerían si el sistema inmunológico se encontrara en su estado normal, sin embargo, esto no significa que sean enfermedades exclusivas de las personas con VIH. Cuando una persona esta infectada con VIH, su sistema inmunológico se ve comprometido es decir, disminuye notablemente su capacidad de atacar a microorganismos patógenos, debido a una reducción en las cuentas de linfocitos T CD4+ (< 200/μl). A partir de este momento, en el que el sistema inmune se encuentra suprimido, diversos microorganismos oportunistas desencadenan una serie de infecciones y algunos tipos de cáncer en el individuo. Una gran proporción de las co-infecciones virales observadas en la infección VIH-SIDA son producidas por miembros de la familia Herpesviridae. En un estudio efectuado en nuestro laboratorio de seroprevalencia por Citomegalovirus, Virus del Herpes Simple tipo 2 y Virusdel Herpes tipo 8 relacionado con Sarcoma de Kaposi, en pacientes infectados con VIH/SIDA bajo tratamiento antiretroviral encontramos que, de un total de 31 individuos infectados con VIH, el 100% presentaron anticuerpos para Citomegalovirus, un 35% para el Virus del Herpes Simple tipo 2 y un 22% para el Virus del Herpes tipo 8 relacionado con el Sarcoma de Kaposi.Palabras Clave: VIH-1, Infecciones Oportunistas, Herpesviridae.HIV-1, Opportunistic infections, Herpesviridae
Measurement of the t t-bar production cross section in the dilepton channel in pp collisions at sqrt(s) = 7 TeV
The t t-bar production cross section (sigma[t t-bar]) is measured in
proton-proton collisions at sqrt(s) = 7 TeV in data collected by the CMS
experiment, corresponding to an integrated luminosity of 2.3 inverse
femtobarns. The measurement is performed in events with two leptons (electrons
or muons) in the final state, at least two jets identified as jets originating
from b quarks, and the presence of an imbalance in transverse momentum. The
measured value of sigma[t t-bar] for a top-quark mass of 172.5 GeV is 161.9 +/-
2.5 (stat.) +5.1/-5.0 (syst.) +/- 3.6(lumi.) pb, consistent with the prediction
of the standard model.Comment: Replaced with published version. Included journal reference and DO
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
Combined search for the quarks of a sequential fourth generation
Results are presented from a search for a fourth generation of quarks
produced singly or in pairs in a data set corresponding to an integrated
luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in
2011. A novel strategy has been developed for a combined search for quarks of
the up and down type in decay channels with at least one isolated muon or
electron. Limits on the mass of the fourth-generation quarks and the relevant
Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a
simple extension of the standard model with a sequential fourth generation of
fermions. The existence of mass-degenerate fourth-generation quarks with masses
below 685 GeV is excluded at 95% confidence level for minimal off-diagonal
mixing between the third- and the fourth-generation quarks. With a mass
difference of 25 GeV between the quark masses, the obtained limit on the masses
of the fourth-generation quarks shifts by about +/- 20 GeV. These results
significantly reduce the allowed parameter space for a fourth generation of
fermions.Comment: Replaced with published version. Added journal reference and DO
Search for New Physics with Jets and Missing Transverse Momentum in pp collisions at sqrt(s) = 7 TeV
A search for new physics is presented based on an event signature of at least
three jets accompanied by large missing transverse momentum, using a data
sample corresponding to an integrated luminosity of 36 inverse picobarns
collected in proton--proton collisions at sqrt(s)=7 TeV with the CMS detector
at the LHC. No excess of events is observed above the expected standard model
backgrounds, which are all estimated from the data. Exclusion limits are
presented for the constrained minimal supersymmetric extension of the standard
model. Cross section limits are also presented using simplified models with new
particles decaying to an undetected particle and one or two jets
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