Promoting Entrepreneurship through a Community Learning Model – Case Study: Green Businesses

This article presents a community learning model formulated by Engineers Without Borders Colombia with the aim of providing communities with tools to create sustainable productive solutions which have relevancy for members and for potential customers. The goal of this formulation is to promote learning processes that are guided by decisions made by community members to propose sustainable and replicable initiatives. The model applicability is evidenced through a case study devoted to strengthening community-led green businesses in the Guavio Province, Colombia by collecting lessons and conclusions. Ultimately, this collection will prove useful in replicating the learning model in other similar rural communities.

     

The circadian molecular clock creates epidermal stem cell heterogeneity

Murine epidermal stem cells undergo alternate cycles of dormancy and activation, fuelling tissue renewal. However, only a subset of stem cells becomes active during each round of morphogenesis, indicating that stem cells coexist in heterogeneous responsive states. Using a circadian-clock reporter-mouse model, here we show that the dormant hair-follicle stem cell niche contains coexisting populations of cells at opposite phases of the clock, which are differentially predisposed to respond to homeostatic cues. The core clock protein Bmal1 modulates the expression of stem cell regulatory genes in an oscillatory manner, to create populations that are either predisposed, or less prone, to activation. Disrupting this clock equilibrium, through deletion of Bmal1 (also known as Arntl) or Per1/2, resulted in a progressive accumulation or depletion of dormant stem cells, respectively. Stem cell arrhythmia also led to premature epidermal ageing, and a reduction in the development of squamous tumours. Our results indicate that the circadian clock fine-tunes the temporal behaviour of epidermal stem cells, and that its perturbation affects homeostasis and the predisposition to tumorigenesis.     

A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation

The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto. It resides at present at 95.7 astronomical units (1?AU is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 UT. The event is consistent with a spherical shape for Eris, with radius 1,163?±?6?kilometres, density 2.52?±?0.05 grams per cm(3) and a high visible geometric albedo, Pv = 0.96(+0.09)(-0.04). No nitrogen, argon or methane atmospheres are detected with surface pressure larger than ～1?nanobar, about 10,000 times more tenuous than Pluto's present atmosphere. As Pluto's radius is estimated to be between 1,150 and 1,200 kilometres, Eris appears as a Pluto twin, with a bright surface possibly caused by a collapsed atmosphere, owing to its cold environment. We anticipate that this atmosphere may periodically sublimate as Eris approaches its perihelion, at 37.8 astronomical units from the Sun.     

A decision rule to minimize daily capital charges in forecasting value‐at‐risk

Under the Basel II Accord, banks and other authorized deposit‐taking institutions (ADIs) have to communicate their daily risk estimates to the monetary authorities at the beginning of the trading day, using a variety of value‐at‐risk (VaR) models to measure risk. Sometimes the risk estimates communicated using these models are too high, thereby leading to large capital requirements and high capital costs. At other times, the risk estimates are too low, leading to excessive violations, so that realized losses are above the estimated risk. In this paper we analyze the profit‐maximizing problem of an ADI subject to capital requirements under the Basel II Accord as ADIs have to choose an optimal VaR reporting strategy that minimizes daily capital charges. Accordingly, we suggest a dynamic communication and forecasting strategy that responds to violations in a discrete and instantaneous manner, while adapting more slowly in periods of no violations. We apply the proposed strategy to Standard & Poor's 500 Index and show there can be substantial savings in daily capital charges, while restricting the number of violations to within the Basel II penalty limits. Copyright © 2009 John Wiley & Sons, Ltd.     

Exploring Survey‐Based Inflation Forecasts

This paper first shows that survey‐based expectations (SBE) outperform standard time series models in US quarterly inflation out‐of‐sample prediction and that the term structure of survey‐based inflation forecasts has predictive power over the path of future inflation changes. It then proposes some empirical explanations for the forecasting success of survey‐based inflation expectations. We show that SBE pool a large amount of heterogeneous information on inflation expectations and react more flexibly and accurately to macro conditions both contemporaneously and dynamically. We illustrate the flexibility of SBE forecasts in the context of the 2008 financial crisis. Copyright © 2011 John Wiley & Sons, Ltd.     

A new parasitoid (Hymenoptera: Braconidae: Aphidiinae) of the invasive bamboo aphids Takecallis spp. (Hemiptera: Aphididae) from Western Europe

A long-term survey of tritrophic (plant–aphid–parasitoid) associations in the urban ecosystems of Lleida (Catalonia) and Paris (France) resulted in the detection of associations of two bamboo aphids, Takecallis arundinariae (Essig) and Takecallis taiwanus (Takahashi), respectively, with a new aphid parasitoid species. Trioxys remaudierei Starý & Rakhshani sp. nov. is described and illustrated as a unique parasitoid of Takecallis aphids outside the area of their origin. The new species is easily distinguishable from its congeners in having the ventral prongs of the abdomen fused over two-thirds of their length, then bifurcated towards the tip. The only morphologically similar species is Trioxys betulae (Marshall), which exhibits a clearly different prong shape (and has a different host range, Symydobius Mordvilko and Clethrobius Mordvilko). The new species is compared with allied taxa associated with bamboo aphids. The occurrence of Takecallis taiwanus on bamboo is recorded in France for the first time.

www.zoobank.org/urn:lsid:zoobank.org:pub:ED15BA16-E8A9-4CEA-BDA7-FBAB02FEB091     

What everybody should know about the rat genome and its online resources

It has been four years since the original publication of the draft sequence of the rat genome. Five groups are now working together to assemble, annotate and release an updated version of the rat genome. As the prevailing model for physiology, complex disease and pharmacological studies, there is an acute need for the rat's genomic resources to keep pace with the rat's prominence in the laboratory. In this commentary, we describe the current status of the rat genome sequence and the plans for its impending 'upgrade'. We then cover the key online resources providing access to the rat genome, including the new SNP views at Ensembl, the RefSeq and Genes databases at the US National Center for Biotechnology Information, Genome Browser at the University of California Santa Cruz and the disease portals for cardiovascular disease and obesity at the Rat Genome Database.     

Effects of elevation on litter-size variation among lizard populations in the Sceloporus grammicus complex (Phrynosomatidae) in Mexico

We examined the effect of elevation on litter-size variation in viviparous lizards of the Sceloporus grammicus complex in 10 states of Mexico. Female snout–vent length (SVL) decreased with increasing elevation, and absolute litter size based on embryos also tended to de crease with increasing elevation. However, after controlling for variation in female body size, we found that litter sizes tended to be relatively larger at higher elevation. Elevation therefore appears to influence litter size in these lizards; however, relatively little of the variation is explained by elevation; thus, other factors are likely making substantial contributions to the observed litter-size variation. The S. grammicus complex appears to be a good model system for examining the underlying causes of geographic and elevational variation in lizard life histories. Examinamos el efecto del altitud en la variación del tamaño de camada de las lagartijas vivíparas del complejo Sceloporus grammicus en 10 estados de México. La LHC de las hembras disminuyó con la altitud, y el tamaño absoluto de camada, calculado con base en el número de embriones, también tendió a disminuir. No obstante, después de controlar la variación en el tamaño corporal de las hembras, encontramos que los tamaños de camada tendieron a ser relativamente más grandes en altitudes mayores. La altitud, por tanto, parece influir en el tamaño de camada de estas lagartijas; sin embargo, la altitud explica relativamente poco de la variación, por lo que, es probable que otros factores contribuyan substancialmente a la variación observada en el tamaño de camada. El complejo S. grammicus parece ser un buen sistema para estudiar las causas fundamentales de la variación geográfica y altitudinal en la historia de vida de las lagartijas.