118 research outputs found

    Comparación de la eficacia de distintos productos químicos aplicados mediante tratamiento aéreo en el control del muérdago (Viscum album) sobre Pinus halepensis

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    El objetivo de este trabajo fue comparar la eficacia de diversos productos químicos en el control del muérdago (Viscum album var austriacum) sobre Pinus halepensis. La experiencia consistió en la aplicación mediante tratamiento aéreo de diversas concentraciones de etefon, åcido giberélico y glifosato. Las combinaciones de åcido giberélico y glifosato obtuvieron las mayores eficacias, especialmente la que aplicó 7,8 g/ha de åcido giberélico y 540 g/ha de glifosato.The aim of this work was to compare the effectiveness of several products (such as ethephon, giberelic acid and glyphosate) in the chemical control of mistletoe {Viscum album var austriacum) on Pinus halepensis. The experiment consisted in applying various concentrations of these products by aerial treatment. The combinations of giberelic acid and glyphosate appeared to be the most effective treatments, especially the treatment that applied giberelic acid - 7,8 g/ha and glyphosate - 540 g/ha

    An evaluation of sampling methodology for assessing settlement of temperate fish in seagrass meadows

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    All demersal fish with planktonic larvae settle at some point early in life, generally around the transformation from larvae to juveniles or soon after. Sampling pre-settlement or very young, settled fish is challenging due to spatial concretions within the habitat and the pulsed, rapid nature of the settlement process. There is a lack of robust methods that enable this sampling, but information on the settlement, that represents a mortality bottleneck, is crucial for the follow-up of populations for fisheries and conservation purposes. An empirical evaluation of sampling methods has not been conducted in temperate habitats. Here, we compare six different sampling methods to collect pre- and post-settlement stages of fish to determine the best combination of techniques to utilise in Posidonia oceanica, an endemic Mediterranean seagrass that provides a key nursery habitat for coastal fish. We considered three types of pelagic nets (bongo net, neuston net and ring net), two types of light-traps (Quatrefoil and Ecocean CAREÂź) to sample pre-settled stages and a low-impact epibenthic trawl for recent settlers. Our results show a significantly different size-spectrum for each method, with a continuous range of sizes from 2 mm to 200 mm. The smallest sizes were collected by the bongo net, followed by the ring net, the neuston net, the Quatrefoil, the Ecocean and finally the epibenthic trawl. Our results suggest that an appropriate strategy for collecting and estimating the abundance of key littoral fish species around settlement size is the combination of the Ecocean light trap and the epibenthic trawl

    Observation of nano-indent induced strain fields and dislocation generation in silicon wafers using micro-raman spectroscopy and white beam x-ray topography

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    In the semiconductor manufacturing industry, wafer handling introduces micro-cracks at the wafer edge. During heat treatment these can produce larger, long-range cracks in the wafer which can cause wafer breakage during manufacture. Two complimentary techniques, micro-Raman spectroscopy (ÎŒRS) and White Beam Synchrotron X-ray Topography (WBSXRT) were employed to study both the micro-cracks and the associated strain fields produced by nano-indentations in Si wafers, which were used as a means of introducing controlled strain in the wafers. It is shown that both the spatial lateral and depth distribution of these long range strain fields are relatively isotropic in nature. The Raman spectra suggest the presence of a region under tensile strain beneath the indents, which can indicate a crack beneath the indent and the data strongly suggests that there exists a minimum critical applied load below which cracking will not initiate

    Inflammatory Cytokines Are Associated with Cognitive Dysfunction and Depressive State during Acute Bacterial Infections and the Recovery Phase

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    During a bacterial infection, individuals may present with behavioral changes referred to as sickness behavior, which has been suggested is induced by the inflammatory markers that are released because of the infective immunological challenge. However, few studies have explored this multidimensional phenomenon in naturally occurring conditions. A longitudinal observational study was conducted to explore the role of inflammatory cytokines in mediating the sickness behavior during a bacterial infection. There were 13, 11 and 37 participants in the infection, hospital control and healthy groups, respectively. They were all followed up for 6 weeks and their inflammatory markers were quantified throughout those weeks. Cognitive function and depressive state were assessed by means of the Mini-Mental State Examination (MMSE) and Cornell Scale for Depression in Dementia (CSDD). Reductions in proinflammatory markers C-Reactive protein (CRP), interleukin – 6 (IL6) and tumor necrosis factor-α (TNFα) and increments in anti-inflammatory markers (interleukin – 4 (IL4)) were associated with an improvement in CSDD and MSEE in patients recovering from a bacterial infection. The correlation between inflammatory makers and CSDD was statistically significant for the CRP (r = 0.535, p = 0.001), the IL6 (r = 0.499, p < 0.001), the TNFα (r = 0.235, p = 0.007) and the IL4 (r = −0.321, p = 0.018). Inflammatory cytokines may mediate sickness behavior during acute illness. These results may enhance the understanding of the pathophysiology and potential treatment strategies to palliate this sickness behavior

    The Association between Inflammatory Biomarkers and Cardiovascular Autonomic Dysfunction after Bacterial Infection.

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    Heart rate variability (HRV) is a known measure of cardiac autonomic function. A cardiovascular autonomic dysfunction (CAD), measured as changes in HRV, is usually presented after an infectious process. The aim of the present study is to assess the association between serum inflammatory markers and CAD. For this purpose, 50 volunteers (13 of them recovering from an infection) were recruited and followed-up for 6 weeks. Their serum inflammatory biomarkers (CRP, IL1, IL4, IL6, IL10, and TNFalpha) were quantified throughout those weeks, along with their HRV resting, in response to the Valsalva maneuver, metronome breathing, standing and sustained handgrip. The correlation of within-subject changes in both HRV and inflammatory biomarkers was assessed to evaluate the concurrent changes. An inverse within-subject correlation was found between CRP and HRV in response to the Valsalva maneuver (rho (95% CI)

    Intergenic and Genic Sequence Lengths Have Opposite Relationships with Respect to Gene Expression

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    Eukaryotic genomes are mostly composed of noncoding DNA whose role is still poorly understood. Studies in several organisms have shown correlations between the length of the intergenic and genic sequences of a gene and the expression of its corresponding mRNA transcript. Some studies have found a positive relationship between intergenic sequence length and expression diversity between tissues, and concluded that genes under greater regulatory control require more regulatory information in their intergenic sequences. Other reports found a negative relationship between expression level and gene length and the interpretation was that there is selection pressure for highly expressed genes to remain small. However, a correlation between gene sequence length and expression diversity, opposite to that observed for intergenic sequences, has also been reported, and to date there is no testable explanation for this observation. To shed light on these varied and sometimes conflicting results, we performed a thorough study of the relationships between sequence length and gene expression using cell-type (tissue) specific microarray data in Arabidopsis thaliana. We measured median gene expression across tissues (expression level), expression variability between tissues (expression pattern uniformity), and expression variability between replicates (expression noise). We found that intergenic (upstream and downstream) and genic (coding and noncoding) sequences have generally opposite relationships with respect to expression, whether it is tissue variability, median, or expression noise. To explain these results we propose a model, in which the lengths of the intergenic and genic sequences have opposite effects on the ability of the transcribed region of the gene to be epigenetically regulated for differential expression. These findings could shed light on the role and influence of noncoding sequences on gene expression

    Mutational Biases and Selective Forces Shaping the Structure of Arabidopsis Genes

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    Recently features of gene expression profiles have been associated with structural parameters of gene sequences in organisms representing a diverse set of taxa. The emerging picture indicates that natural selection, mediated by gene expression profiles, has a significant role in determining genic structures. However the current situation is less clear in plants as the available data indicates that the effect of natural selection mediated by gene expression is very weak. Moreover, the direction of the patterns in plants appears to contradict those observed in animal genomes. In the present work we analized expression data for >18000 Arabidopsis genes retrieved from public datasets obtained with different technologies (MPSS and high density chip arrays) and compared them with gene parameters. Our results show that the impact of natural selection mediated by expression on genes sequences is significant and distinguishable from the effects of regional mutational biases. In addition, we provide evidence that the level and the breadth of gene expression are related in opposite ways to many structural parameters of gene sequences. Higher levels of expression abundance are associated with smaller transcripts, consistent with the need to reduce costs of both transcription and translation. Expression breadth, however, shows a contrasting pattern, i.e. longer genes have higher breadth of expression, possibly to ensure those structural features associated with gene plasticity. Based on these results, we propose that the specific balance between these two selective forces play a significant role in shaping the structure of Arabidopsis genes

    An atlas of over 90.000 conserved noncoding sequences provides insight into crucifer regulatory regions

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    Despite the central importance of noncoding DNA to gene regulation and evolution, understanding of the extent of selection on plant noncoding DNA remains limited compared to that of other organisms. Here we report sequencing of genomes from three Brassicaceae species (Leavenworthia alabamica, Sisymbrium irio and Aethionema arabicum) and their joint analysis with six previously sequenced crucifer genomes. Conservation across orthologous bases suggests that at least 17% of the Arabidopsis thaliana genome is under selection, with nearly one-quarter of the sequence under selection lying outside of coding regions. Much of this sequence can be localized to approximately 90,000 conserved noncoding sequences (CNSs) that show evidence of transcriptional and post-transcriptional regulation. Population genomics analyses of two crucifer species, A. thaliana and Capsella grandiflora, confirm that most of the identified CNSs are evolving under medium to strong purifying selection. Overall, these CNSs highlight both similarities and several key differences between the regulatory DNA of plants and other species
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