Effect of 20-years crop rotation and different strategies of fertilization on weed seedbank

Crop rotation is thought to reduce weed density and maintain species diversity, preventing the domination of few competitive weeds. In this work rotations of 1, 2, 4 and 6 years length have been compared in a long-term experiment since 1976. In order to detect the effect of rotation length and fertilization on weed community evolution, a specific study was performed on weed seedbank with soil sampling in 1993 and 2012.Results: show that weed density was not affected by rotation length or fertilization type or rate, and that about 98% of weed species were indifferent to the factors applied. The dominance of Portulaca oleracea and increment of a few grass weeds were consequences of an inadequate management of late emergence and post-harvest weeds. Furthermore, no significant changes in the distribution of seeds longevity groups occurred in the seed-bank from 1993 to 2012. In cropping systems where herbicides are used according to best practices or to In-tegrated Weed Management principles, the effect of rotation on weeds is hard to detect even in long-term experiments. For this, the effect of herbicides must be included in a more general theory of rotational effects

Short-term responses to salinity of soybean and chenopodium album grown in single and mixed-species hydroponic systems

Weeds account for losses in crop yields, and this event might be exacerbated by salinity. Therefore, we investigated the responses of Chenopodium album L. and soybean (Glycine max (L.) Merr.) to salt stress, as well as interferences between species. Ten-day old plants were grown for 1 week in a single- or mixed-species set-up, either with or without 100 mM of NaCl. C. album reduced the biomass of soybean similarly to salt stress, while its growth was unaffected under any condition. C. album decreased the crop protein content when salinity was applied. This effect was ascribed to altered protein metabolism and/or N usage to produce other N metabolites, including osmolytes. The two species did not reciprocally affect the capacity to accumulate Na+, but the weed contained two-fold more Na+ in the leaves. Elevated initial K+ concentration and high K+ delivery to the shoot likely explained the better acclimation of C. album to salinity. C. album produced more phenolics and proline and exhibited greater antioxidant activity, but low lipid peroxidation, in the mixed set-up under salinity. Thus, it is possible that the weed could become more resilient to salinity when growing in a soybean field. In the long term, this might cause significant losses in soybean productivity as expected by the dramatic decline in crop protein content

Optimized Selection of Reliable and Cost-Effective Cyber-Physical System Architectures

We address the problem of synthesizing safety-critical cyber-physical system architectures to minimize a cost function while guaranteeing the desired reliability. We cast the problem as an integer linear program on a reconfigurable graph which models the architecture. Since generating symbolic probability constraints by exhaustive enumeration of failure cases on all possible graph configurations takes exponential time, we propose two algorithms to decrease the problem complexity, i.e. Integer-Linear Programming Modulo Reliability (ILP-MR) and Integer-Linear Programming with Approximate Reliability (ILP-AR). We compare the two approaches and demonstrate their effectiveness on the design of aircraft electric power system architectures

Morphology, geometric morphometrics, and taxonomy in relict deciduous oaks woods in northern Italy

Abstract: The Euganean Hills are a well-known refugee site for thermophilous woody flora in northern Italy. Among the species recorded here, there is Quercus dalechampii. The Euganean Hills are the only northern Italy site where the occurrence of this oak species is considered. The aim of this paper was to verify the presence of Q. dalechampii in the study area and to select possible diagnostic morphological traits that are usable to distinguish it from Q. petraea and Q. pubescens. Forest stands dominated by Q. petraea, Q. pubescens, and the presumed Q. dalechampii were sampled using the phytosociological approach to highlight their ecological features. Leaf and fruit material from 104 oak individuals was analysed from a macro-morphological and micro-morphological point of view. Leaf shape was also analysed using the geometric morphometric approach. All multivariate analysis procedures applied on the matrices of leaf and fruit traits highlighted two main clusters of morphological diversity. One was restricted to Q. pubescens individuals, and the other one was a mix of Q. petraea and presumed Q. dalechampii individuals. According to the twig and leaf trichome traits, all presumed Q. dalechampii individuals were classified as belonging to the Q. petraea collective group. Morphological differences between Q. petraea and presumed Q. dalechampii were considered not significant. In conclusion, the occurrence of a third oak species, in addition to Q. petraea and Q. pubescens, was not confirmed for the study area by the results of this paper. Graphic abstract: [Figure not available: see fulltext.]

Low energy inelastic electron scattering from carbon monoxide: I. Excitation of the a³ Π, a'³ Σ ⁺ and A¹ Π electronic states

Differential scattering cross sections for electron excitation of the three lowest excited electron states of carbon monoxide are obtained experimentally using low-energy electron energy-loss spectroscopy and theoretically using the R-matrix method. The incident electron energies range from near-threshold of 6.3 eV to 20 eV. Experimental scattering angles range from 20° to 120°. The normalization of the experimental cross sections is made to available experimental elastic scattering data (Gibson et al 1996 J. Phys. B: At. Mol. Opt. Phys. 29 3197). The R-matrix calculations use three distinct close-coupling models and their results are compared to available experimental and theoretical cross sections. The overall comparison leads to significantly improved description of the excitation cross sections for this target

Increasing the germination percentage of a declining native orchid (Himantoglossum adriaticum) by pollen transfer and outbreeding between populations

The declining native orchid Himantoglossum adriaticum H. Baumann is a European endemic of priority interest (92/43/ EEC, Annex II). Northern Italian populations of H. adriaticum are small and isolated, with depressed seed set. Given the important implications for plant population conservation, we tested the hypothesis that artificial pollen transfer (hand-pollination) and outbreeding between populations increases fruit set and seed germination percentage. The background fruit set and in vitro germination rates were determined for ten reference populations. An artificial cross-pollination experiment included (a) pollen transfer from one large population to two small and isolated populations; (b) pollen transfer between two small but not isolated populations; (c) within-population pollen transfer (control). All seeds were sown on a modified Malmgren's medium and cultured in a controlled environment. Germination percentage was compared using a Kruskal-Wallis anova. The background fruit set (mean = 18%) and germination (<5%) rates were consistently low across populations. Fruit set after hand-pollination was consistently 100%. Pollen transfer from the largest population to smaller populations resulted in an increase in total germination ranging from 0.9% to 2.9%. The largest increase in germination occurred between small-sized and less isolated populations (from 1.7% to 5.1%). The results of pollen transfer between the small populations are particularly encouraging, as the mean increase in germination was almost four times that of the control. Outbreeding can be considered a valuable tool to increase genetic flow and germination in natural populations, limit the accumulation of detrimental effects on fitness driven by repeated breeding with closely-related individuals, thereby increasing the possibility of conservation of rare or endangered species

The combination of gefitinib and RAD001 inhibits growth of HER2 overexpressing breast cancer cells and tumors irrespective of trastuzumab sensitivity

<p>Abstract</p> <p>Background</p> <p>HER2-positive breast cancers exhibit high rates of innate and acquired resistance to trastuzumab (TZ), a HER2-directed antibody used as a first line treatment for this disease. TZ resistance may in part be mediated by frequent co-expression of EGFR and by sustained activation of the mammalian target of rapamycin (mTOR) pathway. Here, we assessed feasibility of combining the EGFR inhibitor gefitinib and the mTOR inhibitor everolimus (RAD001) for treating HER2 overexpressing breast cancers with different sensitivity to TZ.</p> <p>Methods</p> <p>The gefitinib and RAD001 combination was broadly evaluated in TZ sensitive (SKBR3 and MCF7-HER2) and TZ resistant (JIMT-1) breast cancer models. The effects on cell growth were measured in cell based assays using the fixed molar ratio design and the median effect principle. <it>In vivo </it>studies were performed in Rag2M mice bearing established tumors. Analysis of cell cycle, changes in targeted signaling pathways and tumor characteristics were conducted to assess gefitinib and RAD001 interactions.</p> <p>Results</p> <p>The gefitinib and RAD001 combination inhibited cell growth <it>in vitro </it>in a synergistic fashion as defined by the Chou and Talalay median effect principle and increased tumor xenograft growth delay. The improvement in therapeutic efficacy by the combination was associated <it>in vitro </it>with cell line dependent increases in cytotoxicity and cytostasis while treatment <it>in vivo </it>promoted cytostasis. The most striking and consistent therapeutic effect of the combination was increased inhibition of the mTOR pathway (<it>in vitro </it>and <it>in vivo</it>) and EGFR signaling <it>in vivo </it>relative to the single drugs.</p> <p>Conclusions</p> <p>The gefitinib and RAD001 combination provides effective control over growth of HER2 overexpressing cells and tumors irrespective of the TZ sensitivity status.</p

Captive reptile mortality rates in the home and implications for the wildlife trade

The trade in wildlife and keeping of exotic pets is subject to varying levels of national and international regulation and is a topic often attracting controversy. Reptiles are popular exotic pets and comprise a substantial component of the live animal trade. High mortality of traded animals raises welfare concerns, and also has implications for conservation if collection from the wild is required to meet demand. Mortality of reptiles can occur at any stage of the trade chain from collector to consumer. However, there is limited information on mortality rates of reptiles across trade chains, particularly amongst final consumers in the home. We investigated mortality rates of reptiles amongst consumers using a specialised technique for asking sensitive questions, additive Randomised Response Technique (aRRT), as well as direct questioning (DQ). Overall, 3.6% of snakes, chelonians and lizards died within one year of acquisition. Boas and pythons had the lowest reported mortality rates of 1.9% and chameleons had the highest at 28.2%. More than 97% of snakes, 87% of lizards and 69% of chelonians acquired by respondents over five years were reported to be captive bred and results suggest that mortality rates may be lowest for captive bred individuals. Estimates of mortality from aRRT and DQ did not differ significantly which is in line with our findings that respondents did not find questions about reptile mortality to be sensitive. This research suggests that captive reptile mortality in the home is rather low, and identifies those taxa where further effort could be made to reduce mortality rate