1,167 research outputs found
On the monotonicity of the correction term in Ramanujan's factorial approximation
We present two new proofs of the monotonicity of the correction term
in Ramanujan's refinement of Stirling's formula.Comment: Latex, 5 page
On-farm Cooperator Trials 2010: Effect of Extended-duration Row Covers on Muskmelon and Winter Squash on Bacterial Wilt and Yield
Susceptible cucurbit crops are difficult to grow in Iowa because of bacterial wilt, caused by Erwinia tracheiphila. Striped and spotted cucumber beetles transmit bacterial wilt. Other insect pests such as squash vine borer and squash bugs may also have an economic impact on yield, particularly in squash
Effects of Extended-duration Row Covers on Muskmelons
Cucurbit crops, especially muskmelon and cucumber, attract cucumber beetles, which spread bacterial wilt, causing major crop losses. Striped and spotted cucumber beetles are the only reported insects that transmit bacterial wilt, caused by the bacteria Erwinia trachephila. High beetle densities are associated with high bacterial wilt incidence, which usually occurs during the first stages of plant establishment
Loss of pancreas upon activated Wnt signaling is concomitant with emergence of gastrointestinal identity
Organ formation is achieved through the complex interplay between signaling pathways
and transcriptional cascades. The canonical Wnt signaling pathway plays multiple roles
during embryonic development including patterning, proliferation and differentiation in distinct
tissues. Previous studies have established the importance of this pathway at multiple
stages of pancreas formation as well as in postnatal organ function and homeostasis. In
mice, gain-of-function experiments have demonstrated that activation of the canonical Wnt
pathway results in pancreatic hypoplasia, a phenomenon whose underlying mechanisms
remains to be elucidated. Here, we show that ectopic activation of epithelial canonical Wnt
signaling causes aberrant induction of gastric and intestinal markers both in the pancreatic
epithelium and mesenchyme, leading to the development of gut-like features. Furthermore,
we provide evidence that β -catenin-induced impairment of pancreas formation depends on
Hedgehog signaling. Together, our data emphasize the developmental plasticity of pancreatic
progenitors and further underscore the key role of precise regulation of signaling pathways
to maintain appropriate organ boundaries
Bacterial wilt symptoms are impacted by host age and involve net downward movement of Erwinia tracheiphila in muskmelon
Cucurbit bacterial wilt, caused by Erwinia tracheiphila, is a damaging disease of cucurbit crops in the Midwest and Northeast U.S. Current management of bacterial wilt relies primarily on insecticide applications to control striped and spotted cucumber beetles (Acalymma vittatum and Diabrotica undecimpunctata howardi, respectively), which vector E. tracheiphila. Development of alternative management strategies is constrained by a lack of understanding of bacterial wilt etiology. The impact of host age on rate on symptom development and extent of bacterial movement in the xylem of muskmelon (Cucumis melo cv. Athena) was evaluated following wound inoculation of 2- to 8-week-old plants in growth chamber experiments. Wilting occurred more rapidly in plants after inoculating E. tracheiphila into 2- or 4-week-old plants than 6- or 8-week-old plants. Recovery of viable cells from stem segments revealed that vascular spread of E. tracheiphila was more extensive below than above the inoculation point. These findings provide experimental evidence that host age impacts the rate of symptom development in cucurbit bacterial wilt and that movement of the xylem-inhabiting pathogen E. tracheiphila within muskmelon plants occurs primarily in the downward direction
The health risks and benefits of cycling in urban environments compared with car use: health impact assessment study
Objective To estimate the risks and benefits to health of travel by bicycle, using a bicycle sharing scheme, compared with travel by car in an urban environment
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