Defect Induced Photoluminescence from Dark Excitonic States in Individual Single-Walled Carbon Nanotubes

We show that new low-energy photoluminescence (PL) bands can be created in semiconducting single-walled carbon nanotubes by intense pulsed excitation. The new bands are attributed to PL from different nominally dark excitons that are "brightened" due to defect-induced mixing of states with different parity and/or spin. Time-resolved PL studies on single nanotubes reveal a significant reduction of the bright exciton lifetime upon brightening of the dark excitons. The lowest energy dark state has longer lifetimes and is not in thermal equilibrium with the bright state.Comment: 4 pages, 3 figure

Educación para el desarrollo humano, educación como ayuda al crecimiento

El fenómeno social de la pobreza, es una de las mayores preocupaciones de las políticas de desarrollo a escala mundial, y es también uno de los más dificiles de solucionar. A pesar de los logros conseguidos hasta el momento, no se ha podido romper su presencia cíclica en todos los países del planeta. Con la mirada esperanzada puesta en el futuro, se propone en este trabajo titulado “Educación para el desarrollo humano, educación como ayuda al crecimiento”, una tesis sencilla: se trata de procurar prepapar el desarrollo, a través de la educación, en la infancia. Lo sugerente de la propuesta es que, aquí, se entiende la educación como ayuda al crecimiento y que el desarrollo para ser eficaz debe ser puesto en marcha en el ámbito más cercano a las personas: el local o comunitario. Así, y como forma de luchar contra la pobreza, se propone una educación que, desde la infancia, prepare a los individuos para actuar de forma libre, comprometida y responsable en la mejora de las condiciones de vida que le rodean. Cuánto más crezca cada miembro de la comunidad como persona, más activamente podrá luchar contra la pobreza y a favor de su propio desarrollo y el de sus convecinos

Power-Law Time Distribution of Large Earthquakes

We study the statistical properties of time distribution of seimicity in California by means of a new method of analysis, the Diffusion Entropy. We find that the distribution of time intervals between a large earthquake (the main shock of a given seismic sequence) and the next one does not obey Poisson statistics, as assumed by the current models. We prove that this distribution is an inverse power law with an exponent $\mu=2.06 \pm 0.01$. We propose the Long-Range model, reproducing the main properties of the diffusion entropy and describing the seismic triggering mechanisms induced by large earthquakes.Comment: 4 pages, 3 figures. Revised version accepted for publication. Typos corrected, more detailed discussion on the method used, refs added. Phys. Rev. Lett. (2003) in pres

Finite-sample frequency distributions originating from an equiprobability distribution

Given an equidistribution for probabilities p(i)=1/N, i=1..N. What is the expected corresponding rank ordered frequency distribution f(i), i=1..N, if an ensemble of M events is drawn?Comment: 4 pages, 4 figure

Cataract and optic disk drusen in a patient with glycogenosis and di George syndrome: clinical and molecular report

Background We report the ophthalmic findings of a patient with type Ia glycogen storage disease (GSD Ia), DiGeorge syndrome (DGS), cataract and optic nerve head drusen (ONHD). Case presentation A 26-year-old white woman, born at term by natural delivery presented with a post-natal diagnosis of GSD Ia. Genetic testing by array-comparative genomic hybridization (CGH) for DGS was required because of her low levels of serum calcium. The patient has been followed from birth, attending the day-hospital every six months at the San Paolo Hospital, Milan, outpatient clinic for metabolic diseases and previously at another eye center. During the last day-hospital visit, a complete eye examination showed ONHD and cataract in both eyes. Next Generation Sequencing (NGS) was subsequently done to check for any association between the eye problems and metabolic aspects. Conclusions This is the first description of ocular changes in a patient with GSD Ia and DGS. Mutations explaining GSD Ia and DGS were found but no specific causative mutation for cataract and ONHD. The metabolic etiology of her lens changes is known, whereas the pathogenesis of ONHD is not clear. Although the presence of cataract and ONHD could be a coincidence; the case reported could suggest that hypocalcemia due to DGS could be the common biochemical pathway

Exciton decay dynamics in individual carbon nanotubes at room temperature

We studied the exciton decay dynamics of individual semiconducting single-walled carbon nanotubes at room temperature using time-resolved photoluminescence spectroscopy. The photoluminescence decay from nanotubes of the same (n,m) type follows a single exponential decay function, however, with lifetimes varying between about 1 and 40 ps from nanotube to nanotube. A correlation between broad photoluminescence spectra and short lifetimes was found and explained by defects promoting both nonradiative decay and vibronic dephasing

Correlation function and generalized master equation of arbitrary age

We study a two-state statistical process with a non-Poisson distribution of sojourn times. In accordance with earlier work, we find that this process is characterized by aging and we study three different ways to define the correlation function of arbitrary age of the corresponding dichotomous fluctuation based respectively on the Generalized Master Equation formalism, on a Liouville-like approach and on a trajectory perspective.Comment: 11 pages, 1figur

Primary tumor sidedness and benefit from FOLFOXIRI plus bevacizumab as initial therapy for metastatic colorectal cancer. Retrospective analysis of the TRIBE trial by GONO

Right-sided metastatic colorectal cancer (mCRC) patients have poor prognosis and achieve limited benefit from first-line doublets plus a targeted agent. In this unplanned analysis of the TRIBE study, we investigated the prognostic and predictive impact of primary tumor sidedness in mCRC patients and the differential impact of the intensification of the chemotherapy in subgroups defined according to both primary tumor sidedness and RAS and BRAF mutational status

Close kinship within multiple-genotype malaria parasite infections

Malaria infections containing multiple parasite genotypes are ubiquitous in nature, and play a central role in models of recombination, intra-host dynamics, virulence, sex ratio, immunity and drug resistance evolution in Plasmodium. While these multiple infections (MIs) are often assumed to result from superinfection (bites from multiple infected mosquitoes), we know remarkably little about their composition or generation. We isolated 336 parasite clones from eight patients from Malawi (high transmission) and six from Thailand (low transmission) by dilution cloning. These were genotyped using 384 single-nucleotide polymorphisms, revealing 22 independent haplotypes in Malawi (2–6 per MI) and 15 in Thailand (2–5 per MI). Surprisingly, all six patients from Thailand and six of eight from Malawi contained related haplotypes, and haplotypes were more similar within- than between-infections. These results argue against a simple superinfection model. Instead, the observed kinship patterns may be explained by inoculation of multiple related haploid sporozoites from single mosquito bites, by immune suppression of parasite subpopulations within infections, and serial transmission of related parasites between people. That relatedness is maintained in endemic areas in the face of repeated bites from infected mosquitoes has profound implications for understanding malaria transmission, immunity and intra-host dynamics of co-infecting parasite genotypes

Scaling detection in time series: diffusion entropy analysis

The methods currently used to determine the scaling exponent of a complex dynamic process described by a time series are based on the numerical evaluation of variance. This means that all of them can be safely applied only to the case where ordinary statistical properties hold true even if strange kinetics are involved. We illustrate a method of statistical analysis based on the Shannon entropy of the diffusion process generated by the time series, called Diffusion Entropy Analysis (DEA). We adopt artificial Gauss and L\'{e}vy time series, as prototypes of ordinary and anomalus statistics, respectively, and we analyse them with the DEA and four ordinary methods of analysis, some of which are very popular. We show that the DEA determines the correct scaling exponent even when the statistical properties, as well as the dynamic properties, are anomalous. The other four methods produce correct results in the Gauss case but fail to detect the correct scaling in the case of L\'{e}vy statistics.Comment: 21 pages,10 figures, 1 tabl