92 research outputs found
Fostering savings by commitment: Evidence from a quasi-natural experiment at The Small Enterprise Foundation in South Africa
We studied the effects of a pilot project that strengthened savings incentive mechanisms. The project was established by The Small Enterprise Foundation (SEF), a leading microfinance institution based in South Africa. The program introduced a savings stimulus in the form of a Goal Card: clients subscribing to this (non-coercive) tool were required to identify a savings goal and to commit to regular payments to reach it. The experiment had a quasi-natural approach as it was implemented by SEF in non-randomly selected locations. Difference-in-differences estimates show improved savings habits among those of the foundation's customers who were involved in the program, compared to the counterfactual that are identified using propensity score matching. The effect of the program manifested in its second semester, suggesting a persistent change of habits but a slow accumulation of savings. We conclude that asking microcredit customers to identify a savings goal and commit to a regular savings amount to achieve it is a promising savings incentive mechanism
High-contrast Ultrabroadband Frontend Source for High Intensity Few-Cycle Lasers
An ultrabroadband seed source for high-power, high-contrast OPCPA systems at
800 nm is presented. The source is based on post compression in a hollow-core
fiber followed by crossed polarized waves (XPW) filtering and is capable of
delivering 80J, 5fs, CEP-stable (0.3rad RMS) pulses with excellent
spectral and temporal qualit
VBL: Virtual Biophysics Lab
VBL (Virtual Biophysics Lab) is a computational project to develop a basic numerical model of tumor spheroids. This paper is a status report that describes the structure of the code that implements the model, and the progress made up to February 2008, and also some recent results in modeling the effects of radiations on cells in a bioreactor
A quantitative study on the growth variability of tumour cell clones in vitro
Objectives: In this study, we quantify the growth variability of tumour cell
clones from a human leukemia cell line. Materials and methods: We have used
microplate spectrophotometry to measure the growth kinetics of hundreds of
individual cell clones from the Molt3 cell line. The growth rate of each clonal
population has been estimated by fitting experimental data with the logistic
equation. Results: The growth rates were observed to vary among different
clones. Up to six clones with a growth rate above or below the mean growth rate
of the parent population were further cloned and the growth rates of their
offsprings were measured. The distribution of the growth rates of the subclones
did not significantly differ from that of the parent population thus suggesting
that growth variability has an epigenetic origin. To explain the observed
distributions of clonal growth rates we have developed a probabilistic model
assuming that the fluctuations in the number of mitochondria through successive
cell cycles are the leading cause of growth variability. For fitting purposes,
we have estimated experimentally by flow cytometry the maximum average number
of mitochondria in Molt3 cells. The model fits nicely the observed
distributions of growth rates, however, cells in which the mitochondria were
rendered non functional (rho-0 cells) showed only a 30% reduction in the clonal
growth variability with respect to normal cells. Conclusions: A tumor cell
population is a dynamic ensemble of clones with highly variable growth rate. At
least part of this variability is due to fluctuations in the number of
mitochondria.Comment: 31 pages, 5 figure
Efficient cross polarized wave generation for compact, energy-scalable, ultrashort laser sources
International audienceThe generation of high contrast and ultrashort laser pulses via a compact and energy-scalable cross polarized wave filter is presented. The setup incorporates a waveguide spatial filter into a single crystal XPW configuration, enabling high energy and high intensity transmission, efficient contrast enhancement and pulse shortening at the multi-mJ level. Excellent XPW conversion of up to 33% (global efficiency: 20%, intensity transmission: 40%) led to an output energy of 650 ?J for an input of 3.3 mJ. Additionally, efficient conversion under specific input phase conditions, allowed pulse shortening from 25 fs to 9.6 fs, indicating the prospective application of this setup as a high energy, ultrabroad laser source. © 2010 Optical Society of America
High-contrast 10-fs OPCPA-based Front-End for the Apollon-10PW laser (Orale)
International audienceWe present a high-contrast 10-fs Front-End for Ti:sapphire PW-lasers within the Apollon-10PW project. This injector uses OPCPA pumped at 100 Hz by Yb-based CPA chain. Combination of OPCPA and XPW permits a >10 12 contrast ratio
A gallotannin-rich fraction from Caesalpinia spinosa (Molina) Kuntze displays cytotoxic activity and raises sensitivity to doxorubicin in a leukemia cell line
<p>Abstract</p> <p>Background</p> <p>Enhancement of tumor cell sensitivity may help facilitate a reduction in drug dosage using conventional chemotherapies. Consequently, it is worthwhile to search for adjuvants with the potential of increasing chemotherapeutic drug effectiveness and improving patient quality of life. Natural products are a very good source of such adjuvants.</p> <p>Methods</p> <p>The biological activity of a fraction enriched in hydrolysable polyphenols (P2Et) obtained from <it>Caesalpinia spinosa </it>was evaluated using the hematopoietic cell line K562. This fraction was tested alone or in combination with the conventional chemotherapeutic drugs doxorubicin, vincristine, etoposide, camptothecin and taxol. The parameters evaluated were mitochondrial depolarization, caspase 3 activation, chromatin condensation and clonogenic activity.</p> <p>Results</p> <p>We found that the P2Et fraction induced mitochondrial depolarization, activated caspase 3, induced chromatin condensation and decreased the clonogenic capacity of the K562 cell line. When the P2Et fraction was used in combination with chemotherapeutic drugs at sub-lethal concentrations, a fourfold reduction in doxorubicin inhibitory concentration 50 (IC<sub>50</sub>) was seen in the K562 cell line. This finding suggested that P2Et fraction activity is specific for the molecular target of doxorubicin.</p> <p>Conclusions</p> <p>Our results suggest that a natural fraction extracted from <it>Caesalpinia spinosa </it>in combination with conventional chemotherapy in combination with natural products on leukemia cells may increase therapeutic effectiveness in relation to leukemia.</p
Judicial disagreement need not be political: dissent on the Estonian Supreme Court
I investigate the non-unanimous decisions of judges on the Estonian Supreme Court. I argue that since judges on the court enjoy high de jure independence, dissent frequently, and are integrated in the normal judicial hierarchy, the Estonian Supreme Court is a crucial case for the presumption that judicial disagreement reveals policy preferences. I analyse dissenting opinions using an ideal point response model. Examining the characteristics of cases which discriminated with respect to the recovered dimension, I show that this dimension cannot be interpreted as a meaningful policy dimension, but instead reflects disagreement about the proper scope of constitutional redress
Loans and Leaving: Migration and the Expansion of Microcredit in Cambodia
Over the last decade, the expansion of microfinance institutions (MFIs) has dramatically shifted the availability of credit across the developing world. This recent development provides an opportunity to examine the relationship between household labor migration and access to and use of formal credit. Both theories of migration and the expectations of formal credit providers have suggested that labor migration and credit are substitute solutions to the demand for capital in the developing world, with the implication that greater access to formal financial services may stem migration out of rural places. Using household survey data from Cambodia, an MFI-saturated country, we find that households using formal credit and households with greater access to formal credit are more likely to have labor migrants than households without access. This association persists across size of loan, purpose of loan, remittances behavior, and for domestic migrations. These findings complicate our understanding of the relationship between credit and migration, and call for a greater recognition of the importance of context in framing migration behavior
patrimonio intelectual
Actas de congresoLas VI Jornadas se realizaron con la exposición de ponencias que se incluyeron en cuatro ejes temáticos, que se desarrollaron de modo sucesivo para facilitar la asistencia, el intercambio y el debate, distribuidos en tres jornadas.
Los ejes temáticos abordados fueron:
1. La enseñanza como proyecto de investigación. Recursos de enseñanza-aprendizaje como mejoras de la calidad educativa.
2. La experimentación como proyecto de investigación. Del ensayo a la aplicabilidad territorial, urbana, arquitectónica y de diseño industrial.
3. Tiempo y espacio como proyecto de investigación. Sentido, destino y usos del patrimonio construido y simbólico.
4. Idea constructiva, formulación y ejecución como proyecto de investigación. Búsqueda y elaboración de resultados que conforman los proyectos de la arquitectura y el diseño
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