5,820 research outputs found
When is capital enough to get female microenterprises growing? Evidence from a randomized experiment in Ghana
Standard models of investment predict that credit-constrained firms should grow rapidly when given additional capital, and that how this capital is provided should not effect decisions to invest in the business or consume the capital. We randomly gave cash and in-kind grants to male- and female-owned microenterprises in urban Ghana. Our findings cast doubt on the ability of capital alone to stimulate the growth of female microenterprises. First, while the average treatment effects of the in-kind grants are large and positive for both males and females, the gain in profits is almost zero for women with initial profits below the median, suggesting that capital alone is not enough to grow subsistence enterprises owned by women. Second, for women we strongly reject equality of the cash and in-kind grants;
only in-kind grants lead to growth in business profits. The results for men also suggest a lower impact of cash, but differences between cash and in-kind grants are less robust. The difference in the effects of cash and in-kind grants is associated more with a lack of self-control than with external pressure. As a result, the manner in which funding is provided affects microenterprise growth
The Dutch Energy Markets in 2009: Target Scenario – Obstacles – Measures
Competition on the wholesale gas market is still in its early stages. Measures have already been put in place to eliminate some shortcomings, these are the new market model and the market-based balancing system. Both of these are the result of the Gas Letter from the Minister and the underlying TTF advice from the NMa. These measures facilitate a development towards more competition. But for a better functioning market the commitment of all market participants is required. Gasterra, the exclusive marketer of Groningen gas, has a key responsibility here. Energy suppliers should be able to obtain gas on the TTF in the required periods and quantities. Otherwise the development of the wholesale gas market will just be stalled further.Monitoring, electricity, gas, competition, infrastructure
The One-Loop Matter Bispectrum in the Effective Field Theory of Large Scale Structures
Given the importance of future large scale structure surveys for delivering
new cosmological information, it is crucial to reliably predict their
observables. The Effective Field Theory of Large Scale Structures (EFTofLSS)
provides a manifestly convergent perturbative scheme to compute the clustering
of dark matter in the weakly nonlinear regime in an expansion in , where is the wavenumber of interest and is the
wavenumber associated to the nonlinear scale. It has been recently shown that
the EFTofLSS matches to level the dark matter power spectrum at redshift
zero up to Mpc and Mpc at one
and two loops respectively, using only one counterterm that is fit to data.
Similar results have been obtained for the momentum power spectrum at one loop.
This is a remarkable improvement with respect to former analytical techniques.
Here we study the prediction for the equal-time dark matter bispectrum at one
loop. We find that at this order it is sufficient to consider the same
counterterm that was measured in the power spectrum. Without any remaining free
parameter, and in a cosmology for which is smaller than in the
previously considered cases (), we find that the prediction from
the EFTofLSS agrees very well with -body simulations up to Mpc, given the accuracy of the measurements, which is of order a few
percent at the highest 's of interest. While the fit is very good on average
up to Mpc, the fit performs slightly worse on
equilateral configurations, in agreement with expectations that for a given
maximum , equilateral triangles are the most nonlinear.Comment: 39 pages, 12 figures; v2: JCAP published version, improved numerical
data, added explanation and clarification
When is capital enough to get female microenterprises growing? Evidence from a randomized experiment in Ghana
Standard models of investment predict that credit-constrained firmd should grow rapidly when given additional capital, and that how this capital is provided should not affect decisions to invest in the business or consume the capital. We randomly gave cash and in-kind grants to male- and female- owned microenterprises in urban Ghana. Our findings cast doubt on the ability of caoital alone to stimulate the growth of female microenterprises. First, while the average treatment effects of the in-kind grants are large and positive for both males and females, the gain in profits is almost zerp fpr women with itital profits below the median, suggesting that capital alone is not enough to grow subsistence enterprises owned by women. Second, for women we strongly reject equality of the case and in-kind grants; only in-kind grants lead to growth in business profits. The results for men also suggest a lower impact of cash, but differences between cash and in-kind grants is assoicated more with a lack of self-control than with external pressure. As a result, the manner in which funding is provided affects microenterprise growth.microenterprises; ghana; Conditionality; Asset intergration
Total syntheses of keramaphidin B and nominal njaoamine I & studies towards the total synthesis of providencin
After the discovery of manzamine A, a macrocyclic marine alkaloid, Baldwin and Whitehead proposed the biogenesis of a whole class of natural products arising from partly reduced alkylpyridine derivatives. Although manzamine A was quickly conquered by total synthesis around the turn of the millennium, a family of alkaloids emerging early in the biogenesis of these natural products remained elusive. In a total synthesis campaign, alkaloids of the ingenamine estate were targeted, pursuing an approach purely based on chemical logic. Therein, a Michael/Michael cascade was developed forging the common tricyclic core in diastereoselective fashion. Furthermore, the transformation proved highly flexible concerning the introduction of requisite handles for macrocyclization. For the total synthesis of keramaphidin B the macrocyclization strategy relied on the use of ring-closing alkyne metathesis (RCAM) for the 13-membered macrocycle and ring-closing olefin metathesis (RCM) for the 11-membered macrocycle. While the RCAM proved highly reliable, the RCM reaction had to be optimized carefully. Eventually, however, the inaugural total synthesis of keramaphidin B was accomplished in 19 steps along the longest linear sequence (LLS) and 0.93% overall yield. As the more recently discovered njaoamines carry an additional Lewis basic amine functionality in the quinoline annulated to one of the macrocycles, the use of RCM became less inviting. After the identification of vic-dibromoalkenes as sufficient alkyne surrogates, nominal njaoamine I was synthesized employing two subsequent RCAMs in 21 steps LLS and 1.14% overall yield. The total synthesis revealed a positional misassignment of the triple bond in the 17-membered macrocycle, which was revised by an in-depth NMR study.
Furanocembranoids are a diverse family of diterpenes. Their macrocyclic framework features, in most cases, a furan and butenolide moiety of some sort. One of the most intriguing molecules found within this class is providencin. Apart from its highly oxygenated nature it is recognized easily by the trans-fused cyclobutane bearing an allylic alcohol and an exocyclic methylene unit. Despite numerous efforts to bring this target down by total synthesis, providencin remains elusive. In particular the exceptionally high ring-strain of the macrocycle and the highly functionalized cyclobutane represent major challenges in an attempted synthesis. Herein, a new route towards the cyclobutane sector of providencin was established, which was used to evaluate the application of RCAM in the context of macrocyclization. At the centerpiece, an Ir-catalyzed photosensitized [2+2] cycloaddition was harnessed to build the furanyl-cyclobutanol fragment. Stereochemical relay of a neighboring stereocenter onto the cyclobutane rendered this approach asymmetric. Furthermore, this handle served as the linchpin to open the thus constructed bicycle via oxidative cleavage. Subsequent functionalization of the furan with a highly electrophilic hypoiodite reagent opened entry into a 2-iodofuran paramount for coupling requisite handles for macrocyclization. At this stage, Suzuki coupling was found to be optimal and an alkyne-bearing E-olefinic fragment could be introduced into the molecule. After accessing a viable diyne it became clear that the macrocycle was too strained to be forged by RCAM, because this reaction is largely entropically driven. These setbacks notwithstanding, a Suzuki coupling could be carried out with potassium vinyltrifluoroborate giving rise to an intermediate, which is expected to be elaborated into providencin via a literature known route previously established in the group of Mulzer
The effects of halo alignment and shape on the clustering of galaxies
We investigate the effects of halo shape and its alignment with larger scale
structure on the galaxy correlation function. We base our analysis on the
galaxy formation models of Guo et al., run on the Millennium Simulations. We
quantify the importance of these effects by randomizing the angular positions
of satellite galaxies within haloes, either coherently or individually, while
keeping the distance to their respective central galaxies fixed. We find that
the effect of disrupting the alignment with larger scale structure is a ~2 per
cent decrease in the galaxy correlation function around r=1.8 Mpc/h. We find
that sphericalizing the ellipsoidal distributions of galaxies within haloes
decreases the correlation function by up to 20 per cent for r<1 Mpc/h and
increases it slightly at somewhat larger radii. Similar results apply to power
spectra and redshift-space correlation functions. Models based on the Halo
Occupation Distribution, which place galaxies spherically within haloes
according to a mean radial profile, will therefore significantly underestimate
the clustering on sub-Mpc scales. In addition, we find that halo assembly bias,
in particular the dependence of clustering on halo shape, propagates to the
clustering of galaxies. We predict that this aspect of assembly bias should be
observable through the use of extensive group catalogues.Comment: 8 pages, 6 figures. Accepted for publication in MNRAS. Minor changes
relative to v1. Note: this is an revised and considerably extended
resubmission of http://arxiv.org/abs/1110.4888; please refer to the current
version rather than the old on
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