Yields and qualities of pigeonpea varieties grown under smallholder farmers’ conditions in Eastern and Southern Africa

Pigeonpea is one of the few crops with a high potential for resource-poor farmers due to its complementary resource use when intercropped with maize. A three year comprehensive comparative study on the performance of six pigeonpea (Cajanus cajan) varieties on farmers’ fields in Eastern and Southern Africa where intercropping with maize is normal practice, was undertaken. The varieties were tested for accumulation of dry matter (DM), nitrogen (N) and phosphorus (P) in all above-ground organs for three years under farmers’ conditions. The study revealed that the latest introduced ICEAP 00040 outperformed all the other tested varieties (ICP 9145; ICEAP 00020, ICEAP 00053, ICEAP 00068, and a local variety called “Babati White”) under farmer-managed conditions. The harvest indices (HI), ranging from 0.08-0.15 on dry matter (DM) basis, were relatively low and unaffected (P>0.05) by the environmental variation. The N harvest index (NHI) was 0.28 and P harvest index (PHI) was 0.19. The better responses of ICEAP00040 to favourable conditions could however only be realised in a minority of cases as yields generally were low. These low yields are still a major challenge in African smallholder agriculture as pulses play an important role in soil fertility maintenance as well as in the household diets

Complete assessment of elastic properties of trabecular bone architecture from 3D reconstruction images

A method is presented that allows for a complete mechanical evaluation of trabecular bone architecture directly from three-dimensional computer reconstruction images. With this method, the reconstruction images are used as a basis for microstructural FE-analyses. From the results of these analyses the full stiffness matrix of bone specimens is obtained, using a standard mechanics approach. An optimization procedure is then used to find the best orthotropic representation and principal directions of this matrix. The method is demonstrated here relative to two trabecular bone specimens. With the development of in vivo reconstructions and the methods demonstrated here, even in vivo measurements will be possibl

The role of trabecular architecture in the anisotropic mechanical properties of bone

As yet, no unique relationship between mechanical and structural parameters has been established for trabecular bone. A possible explanation for the variability in the relationships obtained so far is that the results of mechanical tests represent more parameters than those of trabecular morphology alone. In the present study, the results of such a mechanical test are compared to results of a numerical experiment, from which the isolated mechanical role of the trabecular architecture of a bone specimen is obtained. A mechanically tested bone specimen was reconstructed in a computer and converted to a microstructural FE-model. The results of experiment and FE-simulation were, obviously, not identical. It is hypothesized that experimental artifacts are the most important factors affecting the mechanical test results, thus causing variability in the relationships. More accurate relationships are expected when these artifacts can be excluded, for example, by using microstructural FE-models

Streaming Algorithm for Euler Characteristic Curves of Multidimensional Images

We present an efficient algorithm to compute Euler characteristic curves of gray scale images of arbitrary dimension. In various applications the Euler characteristic curve is used as a descriptor of an image. Our algorithm is the first streaming algorithm for Euler characteristic curves. The usage of streaming removes the necessity to store the entire image in RAM. Experiments show that our implementation handles terabyte scale images on commodity hardware. Due to lock-free parallelism, it scales well with the number of processor cores. Our software---CHUNKYEuler---is available as open source on Bitbucket. Additionally, we put the concept of the Euler characteristic curve in the wider context of computational topology. In particular, we explain the connection with persistence diagrams

Parallel plate model for trabecular bone exhibits volume fraction-dependent bias

Unbiased stereological methods were used in conjunction with microcomputed tomographic (micro-CT) scans of human and animal bone to investigate errors created when the parallel plate model was used to calculate morphometric parameters. Bone samples were obtained from the human proximal tibia, canine distal femur, rat tail, and pig spine and scanned in a micro-CT scanner. Trabecular thickness, trabecular spacing, and trabecular number were calculated using the parallel plate model. Direct thickness, and spacing and connectivity density were calculated using unbiased three-dimensional methods. Both thickness and spacing calculated using the plate model were well correlated to the direct three-dimensional measures (r(2) = 0. 77-0.92). The correlation between trabecular number and connectivity density varied greatly (r(2) = 0.41-0.94). Whereas trabecular thickness was consistently underestimated using the plate model, trabecular spacing was underestimated at low volume fractions and overestimated at high volume fractions. Use of the plate model resulted in a volume-dependent bias in measures of thickness and spacing (p < 0.001). This was a result of the fact that samples of low volume fraction were much more "rod-like" than those of the higher volume fraction. Our findings indicate that the plate model provides biased results, especially when populations with different volume fractions are compared. Therefore, we recommend direct thickness measures when three-dimensional data sets are available

AVP-stimulated nucleotide secretion in perfused mouse medullary thick ascending limb and cortical collecting duct

Extracellular nucleotides are local, short-lived signaling molecules that inhibit renal tubular transport via both luminal and basolateral P2 receptors (1, 2). Apparently, the renal epithelium itself is able to release nucleotides (3, 4). The mechanism and circumstances under which epithelia nucleotide release is stimulated remains elusive (5, 6). Here, we investigate the phenomenon of nucleotide secretion in intact perfused mouse medullary thick ascending limb (mTAL) and cortical collecting duct (CCD). The nucleotide secretion was monitored by a biosensor cell placed to register nucleotides in the tubular out-flow. [Ca2+]i was measured simultaneously in the biosensor cells and the renal tubule with fluo-4. We were able to identify spontaneous tubular nucleotide secretion in resting perfused mTAL. This was seen as lively [Ca2+]i oscillations in the nucleotide biosensor cells when the tubular outflow fluid engulfed the sensing cells. In mouse mTAL 10 nM AVP and dDAVP induced robust [Ca2+]i oscillations, whereas AVP in the CCD induced large, slow and transient [Ca2+]i elevations. Importantly, we identify that AVP/ dDAVP triggers tubular secretion of nucleotides in mTAL. After addition of AVP/dDAVP the biosensor cells registered bursts of nucleotides originating from the tubular perfusate. The approximated tubular nucleotide concentration reached peak values of ～0.2-0.3μM. A very similar response was observed after AVP stimulation of CCDs. Thus, AVP stimulated tubular secretion of nucleotides in a burst like pattern with peak tubular nucleotide concentrations in the low micromolar range. Luminal nucleotides are prone to activate luminal P2 receptors (1) which in turn are well described to inhibit AVP-augmented aquaporin-2-dependent water absorption (7) or ENaC-mediated Na+ transport (8). Therefore, we speculate that local nucleotide signaling is an intrinsic feed-back element of hormonal control of renal tubular transport (9)

A pragmatic randomised trial of stretching before and after physical activity to prevent injury and soreness

OBJECTIVE: To determine the effects of stretching before and after physical activity on risks of injury and soreness in a community population. DESIGN: Internet-based pragmatic randomised trial conducted between January 2008 and January 2009. SETTING: International. PARTICIPANTS: A total of 2377 adults who regularly participated in physical activity. INTERVENTIONS: Participants in the stretch group were asked to perform 30 s static stretches of seven lower limb and trunk muscle groups before and after physical activity for 12 weeks. Participants in the control group were asked not to stretch. MAIN OUTCOME MEASUREMENTS: Participants provided weekly on-line reports of outcomes over 12 weeks. Primary outcomes were any injury to the lower limb or back, and bothersome soreness of the legs, buttocks or back. Injury to muscles, ligaments and tendons was a secondary outcome. RESULTS: Stretching did not produce clinically important or statistically significant reductions in all-injury risk (HR=0.97, 95% CI 0.84 to 1.13), but did reduce the risk of experiencing bothersome soreness (mean risk of bothersome soreness in a week was 24.6% in the stretch group and 32.3% in the control group; OR=0.69, 95% CI 0.59 to 0.82). Stretching reduced the risk of injuries to muscles, ligaments and tendons (incidence rate of 0.66 injuries per person-year in the stretch group and 0.88 injuries per person-year in the control group; HR=0.75, 95% CI 0.59 to 0.96). CONCLUSION: Stretching before and after physical activity does not appreciably reduce all-injury risk but probably reduces the risk of some injuries, and does reduce the risk of bothersome soreness. TRIAL REGISTRATION: anzctr.org.au 12608000044325

Benthic foraminiferal assemblages and test accumulation in coastal microhabitats on San Salvador, Bahamas

Benthic foraminiferal populations were studied in a shallow bay of San Salvador Island, the Bahamas. Surface sediments and marine macrophytes were collected from 14 sample sites along a 500&thinsp;m transect at Grahams Harbour to investigate the foraminiferal assemblage in each microhabitat and to test the link between dead foraminiferal test accumulation patterns and living epiphytic and sedimentary foraminiferal assemblages, macrophyte distribution, and environmental gradients. The analyses include grain size measurements, macrophyte biomass quantification, and qualitative and quantitative studies of benthic foraminifera. The foraminifera found attached to macrophytes differed between macrophyte habitats. However, a correlation between these living communities and the dead assemblages in the sediments at the same sites could not be observed. Principal component analysis (PCA) and redundancy analysis (RDA) suggest that the presence of the macroalgae Halimeda explains 16&thinsp;% of the residual faunal variation in the dead foraminiferal assemblage after the effects of sorting according to fall speed are partialled out. The RDA also reflects a positive correlation between foraminifera larger than 1.0&thinsp;mm in diameter and the 0.25–0.5&thinsp;mm sediment grain size, indicating sedimentological processes as the main factor controlling the sedimentary epiphytic foraminiferal assemblages. These sedimentary processes overprint most effects of ecological features or macrophyte-specific association.</p