Sucrose effect on broomrape (Orobanche crenata) development on narbon bean (Vicia narbonensis L.)

The growth and development of broomrapes (Orobanche spp.) fully depends on the nutritional connection established between the parasitic plant and the root of the corresponding host plant. In thepresent study, narbon bean plants infected with Orobanche crenata were watered with different concentrations of sucrose (0.014, 0.044, 0.088 and 0.146 M) in order to evaluate its effect on the earlygrowth stages of the parasite. The germination of O. crenata seeds decreased with increasing sucrose concentrations and the number of infection attachments of crenata broomrapes decreased significantlywhen sucrose was present. A parallel experiment was conducted with identical sorbitol concentrations in order to determinate the role of the osmotic potential in the inhibition of the parasite growth. Ourresults showed that while low sucrose concentrations significantly reduced seed germination in O. crenata, similar concentrations of sorbitol have no significant effect thus indicating that the effect ofsucrose is not simply osmotic. Sucrose phytotoxicity was also studied by considering the dry weight of the host plants

Investigation of the origin and magnitude of debris flows from the Payhua Creek basin, Matucana area, Huarochirí Province, Perú

The small city of Matucana (population 5800), Province of Huarochirí, Perú is located on the flood plain of Rimac River in Andes Occidental, approximately 75 km east of Lima at an elevation of 2390 m (area of 11° 50.489’ S, 76° 22.857’ W). Adjacent ridges and mountain peaks rise to 5000 m. Matucana shares a 300m wide valley bottom with two transportation arteries: Carretera Central, the only highway in Perú connecting the Amazon basin to the Pacific Coast and Ferrocarril Central, the highest standard gauge railway in the world which services mines and communities in the Andes. The present course of Rimac River is controlled by a dike and fill for the highway and railroad. These structures confine it to the northern portion of its flood plain. Consequently, parts of Matucana are lower in elevation than the bed of Rimac River. Payhua Creek (PC), a steep, debris-flow-prone tributary to Rimac River, has built an extensive fan at the upstream end of the city. Debris flows from PC has dammed Rimac River and diverted it into Matucana. This type of disaster occurred 1959 and 1983 when heavy precipitation occurred in the normally arid Andes Occidental. The 1959 event was particularly notable as it destroyed 90% of Matucana with loss of life. Although these events were not well documented, investigation of the PC fan and documentation of 1983 deposits on the fan indicate that the 1983 debris flow had a volume in the 0.12 106 to 106m3 range. Investigation of surficial and bedrock geology including mapping of all landslides in PC basin was carried out in 2004. A landslide complex immediately west of Payhua village is the most significant source of debris flow sediment in the basin. Incision of an unfavourable succession of andesite flows overlying a pervasively fractured tuff is responsible for the concentration of landslides in the Payhua village area. The area affected by landsliding in this area has increased by a factor of five since 1951. The PC basin upstream from Payhua has been a relatively small source of debris flows during the past 600 to 800 years based upon archaeological evidence. Exposures of debris flow deposits in the PC fan indicate that debris flow events larger than those of 1959 and 1983 have occurred in the recent geologic past. Matucana has also grown significantly since 1983 and has further encroached on the Rimac River flood plain and the PC fan. As a result, if debris flows of the magnitude of those in 1959 and 1983 occur, direct burial of the upstream area of Matucana by debris flows is likely

Unveiling the nature of the "Green Pea" galaxies

We review recent results on the oxygen and nitrogen chemical abundances in extremely compact, low-mass starburst galaxies at redshifts between 0.1-0.3 recently named to as "Green Pea" galaxies. These galaxies are genuine metal-poor galaxies ($\sim$ one fifth solar) with N/O ratios unusually high for galaxies of the same metallicity. In combination with their known general properties, i.e., size, stellar mass and star-formation rate, these findings suggest that these objects could be experiencing a short and extreme phase in their evolution. The possible action of both recent and massive inflow of gas, as well as stellar feedback mechanisms are discussed here as main drivers of the starburst activity and their oxygen and nitrogen abundances.Comment: To appear in JENAM Symposium "Dwarf Galaxies: Keys to Galaxy Formation and Evolution", P. Papaderos, G. Hensler, S. Recchi (eds.). Lisbon, September 2010, Springer Verlag, in pres

Subtidal macrozoobenthos communities from northern Chile during and post El Niño 1997–1998

Despite a large amount of climatic and oceanographic information dealing with the recurring climate phenomenon El Niño (EN) and its well known impact on diversity of marine benthic communities, most published data are rather descriptive and consequently our understanding of the underlying mechanisms and processes that drive community structure during EN are still very scarce. In this study, we address two questions on the effects of EN on macrozoobenthic communities: (1) how does EN affect species diversity of the communities in northern Chile? and (2) is EN a phenomenon that restarts community assembling processes by affecting species interactions in northern Chile? To answer these questions, we compared species diversity and co-occurrence patterns of soft-bottoms macrozoobenthos communities from the continental shelf off northern Chile during (March 1998) and after (September 1998) the strong EN event 1997–1998. The methods used varied from species diversity and species co-occurrence analyses to multivariate ordination methods. Our results indicate that EN positively affects diversity of macrozoobenthos communities in the study area, increasing the species richness and diversity and decreasing the species dominance. EN represents a strong disturbance that affects species interactions that rule the species assembling processes in shallow-water, sea-bottom environments

The Escherichia coli transcriptome mostly consists of independently regulated modules

Underlying cellular responses is a transcriptional regulatory network (TRN) that modulates gene expression. A useful description of the TRN would decompose the transcriptome into targeted effects of individual transcriptional regulators. Here, we apply unsupervised machine learning to a diverse compendium of over 250 high-quality Escherichia coli RNA-seq datasets to identify 92 statistically independent signals that modulate the expression of specific gene sets. We show that 61 of these transcriptomic signals represent the effects of currently characterized transcriptional regulators. Condition-specific activation of signals is validated by exposure of E. coli to new environmental conditions. The resulting decomposition of the transcriptome provides: a mechanistic, systems-level, network-based explanation of responses to environmental and genetic perturbations; a guide to gene and regulator function discovery; and a basis for characterizing transcriptomic differences in multiple strains. Taken together, our results show that signal summation describes the composition of a model prokaryotic transcriptome

Associations between plasma neurofilament light, in vivo brain pathology, and cognition in non-demented individuals with autosomal-dominant Alzheimer's disease

BACKGROUND: Neurofilament light (NfL) is a promising biomarker of early neurodegeneration in Alzheimer's disease (AD). We examined whether plasma NfL was associated with in vivo amyloid beta and tau, and cognitive performance in non-demented presenilin-1 (PSEN1) E280A mutation carriers. METHODS: Twenty-five mutation carriers and 19 non-carriers (age range: 28 to 49 years) were included in this study. Participants underwent 11C Pittsburgh compound B (PiB)-PET (positron emission tomography), flortaucipir-PET, blood sampling, and cognitive testing. RESULTS: Mutation carriers exhibited higher plasma NfL levels than non-carriers. In carriers, higher NfL levels were related to greater regional tau burden and worse cognition, but not amyloid beta load. When we adjusted for age, a proxy of disease progression, elevated plasma NfL levels were only correlated with worse memory recall. CONCLUSIONS: Findings support an association between plasma NfL, cognition, and tau pathology in non-demented individuals at genetic risk for developing AD dementia. Plasma NfL may be useful for selecting individuals at increased risk and tracking disease progression in AD

Diabetes with Hypertension as Risk Factors for Adult Dengue Hemorrhagic Fever in a Predominantly Dengue Serotype 2 Epidemic: A Case Control Study

Dengue is a major vector borne disease in the tropical and subtropical regions. An estimated 50 million infections occur per annum in over 100 countries. A severe form of dengue, characterized by bleeding and plasma leakage, known as dengue hemorrhagic fever (DHF) is estimated to occur in 1–5% of hospitalized cases. It can be fatal if unrecognized and not treated in a timely manner. Previous studies had found a number of risk factors for DHF. However, screening and clinical management strategies based on these risk factors may not be applicable to all populations and epidemics of different serotypes. In this study, we found significant association between DHF and diabetes mellitus and diabetes mellitus with hypertension during the epidemic of predominantly serotype 2 (year 2007 and 2008), but not during the epidemic of predominantly serotype 1 (year 2006). Diabetes mellitus and hypertension are prevalent in Singapore and most parts of South-East Asia, where dengue is endemic. Therefore, it is important to address the risk effect of these co-morbidities on the development of DHF so as to reduce morbidity and mortality. Our findings may have impact on screening and clinical management of dengue patients, when confirmed in more studies

Adaptive Radiation in Mediterranean Cistus (Cistaceae)

lineage consists of 12 species primarily distributed in Mediterranean habitats and is herein subject to analysis. lineages), which display asymmetric characteristics: number of species (2 vs. 10), leaf morphologies (linear vs. linear to ovate), floral characteristics (small, three-sepalled vs. small to large, three- or five-sepalled flowers) and ecological attributes (low-land vs. low-land to mountain environments). A positive phenotype-environment correlation has been detected by historical reconstructions of morphological traits (leaf shape, leaf labdanum content and leaf pubescence). Ecological evidence indicates that modifications of leaf shape and size, coupled with differences in labdanum secretion and pubescence density, appear to be related to success of new species in different Mediterranean habitats.

From vineyards to feedlots: a fund-flow scanning of sociometabolic transition in the Vallès County (Catalonia) 1860-1956-1999

We analyse the changes to agricultural metabolism in four municipalities of Vallès County (Catalonia, Iberia) by accounting for their agroecosystemfunds and flows during the socioecological transition from organic to industrial farming between the late nineteenth and twentieth centuries. The choice of three different stages in this transition allows us to observe the transformation of its funds and flows over time, the links established between them and the effect on their energy profiles.We emphasize the relevance of the integration and consistency of agroecosystem funds for energy efficiency in agriculture and their role as underlying historical drivers of this socioecological transition. While readjustment to market conditions and availability and affordability of external inputs are considered the main drivers of the transition, we also highlight the role of societal energy and nutritional transitions. An analysis of advanced organic agriculture c. 1860 reveals the great effort required to reproduce soil fertility and livestock from the internal recirculation of biomass. Meanwhile, a balance between land produce and livestock densities enabled the integration of funds, with a positive impact on energy performance. The adoption of fossil fuels and synthetic fertilizers c. 1956 reduced somewhat the pressure exerted on the land by overcoming the former dependence on local biomass flows to reproduce the agroecosystem. Yet external inputs diminished sustainability. Partial dependence on external markets existed congruently with internal crop diversity and the predominance of organic over industrial farm management. A shift towards animal production and consumption led to a new specialization process c. 1999 that resulted in crop homogenization and agroecological landscape disintegration. The energy returns of this linear feed-food livestock bioconversion declined compared to earlier mixed farming. Huge energy flows driven by a globalized economy ran through this agroecosystem, provoking deep impacts at both a local and external scale