Detección de Ralstonia solanacearum en Solanum tuberosum L. en el Estado de Sonora, México

Ralstonia solanacearum (Rs) produce la enfermedad cuarentenaria denominada marchitez bacteriana en papa. México es un país importador de semilla de Estados Unidos de América y Canadá, aspecto significante para provocar una eventual introducción de esta enfermedad en áreas con amplias extensiones de papa. Sonora es una región importante en relación con la producción de este cultivo. Por lo anteriormente expuesto, se realizó la presente investigación, teniendo como objetivos: a) la producción de antisuero para la bacteria Rs; b) diagnosticar Rs en tubérculos de importación que se utilizan para siembra, y en tubérculos de procedencia mexicana para consumo humano, que son utilizados como semilla; c) la detección de la bacteria durante el desarrollo vegetativo de lotes de papa en Sonora, México. Se analizó tubérculo semilla de importación, de consumo humano, plantas de papa, hojas y tubérculos de producción; los métodos de detección utilizados fueron medios de cultivos específicos, ELISA, antisuero producido y pruebas de patogenicidad. Los resultados mostraron positiva la presencia de Rs en tubérculos de consumo; en tubérculos de importación y en etapas vegetativas fue negativa. Cada prueba de detección por separado no debe ser utilizada como método único; la presencia de Rs representa un riesgo de eventual manifestación de la enfermedad, por lo que es necesario que las áreas productoras realicen actividades de control preventivo fitosanitario.

Apropriaçâo da terra e formaçâo de grandes patimônios fundiários na fronteira sul do Brasil, através dos inventários post mortem (1800-1860)

This article is dedicated to the study the ways of appropriation of land in the south border of Brazil, in the first half of the century XIX. The historiography has, for tradition, associated the appropriation of large tracts of land, in Rio Grande do Sul, with royal donations. That would have been made, mainly, in the form of 'sesmarias' donations. However, a more detained study shows than the public concessions were just one among other forms of appropriation of the land used by families that accomplished a voracious accumulation of lands. Among other sources, inventories post mortem, registrations of concessions of lands and official correspondences are used. The main analysis focus relapses on the municipal district of Alegrete, between 1800 and 1870

Apropriaçâo da terra e formaçâo de grandes patimônios fundiários na fronteira sul do Brasil, através dos inventários post mortem (1800-1860)

This article is dedicated to the study the ways of appropriation of land in the south border of Brazil, in the first half of the century XIX. The historiography has, for tradition, associated the appropriation of large tracts of land, in Rio Grande do Sul, with royal donations. That would have been made, mainly, in the form of 'sesmarias' donations. However, a more detained study shows than the public concessions were just one among other forms of appropriation of the land used by families that accomplished a voracious accumulation of lands. Among other sources, inventories post mortem, registrations of concessions of lands and official correspondences are used. The main analysis focus relapses on the municipal district of Alegrete, between 1800 and 1870

Sediment thickness and distribution of facies types in the Kara Sea

We studied the impact of the last glacial (late Weichselian) sea level cycle on sediment architecture in the inner Kara Sea using high-resolution acoustic sub-bottom profiling. The acoustic lines were ground-truthed with dated sediment cores. Furthermore we refined the location of the eastern LGM ice margin, by new sub bottom profiles. New model results of post-Last Glacial Maximum (LGM) isostatic rebound for this area allow a well-constrained interpretation of acoustic units in terms of sequence stratigraphy. The lowstand (or regressive) system tract sediments are absent but are represented by an unconformity atop of Pleistocene sediments on the shelf and by a major incised dendritic paleo-river network. The subsequent transgressive and highstand system tracts are best preserved in the incised channels and the recent estuaries while only minor sediment accumulation on the adjacent shelf areas is documented. The Kara Sea can be subdivided into three areas: estuaries (A), the shelf (B) and (C) deeper lying areas that accumulated a total of 114 * 10**10 t of Holocene sediments.

Apropriaçâo da terra e formaçâo de grandes patimônios fundiários na fronteira sul do Brasil, através dos inventários post mortem (1800-1860)

This article is dedicated to the study the ways of appropriation of land in the south border of Brazil, in the first half of the century XIX. The historiography has, for tradition, associated the appropriation of large tracts of land, in Rio Grande do Sul, with royal donations. That would have been made, mainly, in the form of 'sesmarias' donations. However, a more detained study shows than the public concessions were just one among other forms of appropriation of the land used by families that accomplished a voracious accumulation of lands. Among other sources, inventories post mortem, registrations of concessions of lands and official correspondences are used. The main analysis focus relapses on the municipal district of Alegrete, between 1800 and 1870

Average dip directions from intervals of dipmeter log in drill hole CRP-2A

Bedding dips in the CRP-2A drillhole were determined in two ways (1) analysis of a dipmeter log, and (2) identification of bed boundaries on digital images of the outer core surface. The two methods document the downhole increase in structural dip, to a maximum of 15° in the lowest 150 m of the hole. Dipmeter data, which are azimuthally oriented, indicate a 75° azimuth for structural tilting, in agreement with seismic reflection profiles. Core and log dips indicate that structural dip increases by 5-7° between 325 and 480 mbsf. Both, however, also exhibit high dip inhomogeneity because of depositional (e.g., cross bedding) and post-depositional (e.g., softsediment deformation) processes. This variability adds ambiguity to the search for angular unconformities within the CRP-2A drillhole. Dip directions of different lithologies are generally similar, as are dip directions for the four kinds of systems tracts. Downdip azimuths of sands and muds are slightly different from those of diamicts, possibly reflecting the divergence between ENE offshore dip and ESE glacial advance.

Shallow water foraminifera of ODP Hole 133-821A

Reworked shallow-water foraminifers that settled on the upper slope of the central Great Barrier Reef at Site 821 (water depth, 212.6 m) were used as indicators of the paleoclimatic and paleoenvironmental conditions that have controlled the Pleistocene evolution of the adjacent platform. Throughout the 400-m-thick sequence drilled, the nature, composition, and distribution of the shallow-water foraminiferal assemblages studied indicate that (1) all the species recorded are at present living in diverse tropical, reef-related areas of the Indo-Pacific and Atlantic provinces; (2) the composition of the microfaunal taphocoenoses is almost identical between the different stratigraphic intervals studied and the modern Great Barrier Reef environments; (3) inner-neritic, tropical environments have continued to develop since the middle Pleistocene; (4) high- to moderate-energy platform edges occurred repeatedly throughout Pleistocene time. These factors may suggest that, since the beginning of the Pleistocene, several reef-like tracts have grown successively on the central area of the northeastern Australian shelf edge. These tracts probably had a sufficiently evolved morphological zonation to act as shelters for foraminiferal biocoenoses of high species diversity.

Characteristics and stomach contents of Greenland sharks (Somniosus microcephalus) caught in Svalbard during June 2008-2009

Harbour seals in Svalbard have short longevity, despite being protected from human hunting and having limited terrestrial predation at their haulout sites, low contaminant burdens and no fishery by-catch issues. This led us to explore the diet of Greenland sharks (Somniosus microcephalus) in this region as a potential seal predator. We examined gastrointestinal tracts (GITs) from 45 Greenland sharks in this study. These sharks ranged from 229 to 381 cm in fork length and 136-700 kg in body mass; all were sexually immature. Seal and whale tissues were found in 36.4 and 18.2%, respectively, of the GITs that had contents (n = 33). Based on genetic analyses, the dominant seal prey species was the ringed seal (Pusa hispida); bearded seal (Erignathus barbatus) and hooded seal (Cystophora cristata) tissues were each found in a single shark. The sharks had eaten ringed seal pups and adults based on the presence of lanugo-covered prey (pups) and age determinations based on growth rings on claws (<1 year and adults). All of the whale tissue was from minke whale (Balenoptera acutorostrata) offal, from animals that had been harvested in the whale fishery near Svalbard. Fish dominated the sharks' diet, with Atlantic cod (Gadus morhua), Atlantic wolffish (Anarhichas lupus) and haddock (Melanogrammus aeglefinus) being the most important fish species. Circumstantial evidence suggests that these sharks actively prey on seals and fishes, in addition to eating carrion such as the whale tissue. Our study suggests that Greenland sharks may play a significant predatory role in Arctic food webs.

Sediment composition and sedimentation rates of four Holes in ODP Leg 166

To date, work on the Great Bahama Bank's western, leeward margin has centred chiefly on seismic-scale expressions of carbonate sequences and systems tracts. However, periplatform, slope sediments also exhibit very well developed cyclicity on scales of decimetres to several metres. It is these small-scale, high-frequency cycles within the larger-scale facies successions of the Quaternary which form the main topic of this paper. Previous studies have shown that the small-scale cycles correlate to the orbitally forced, high-frequency sea-level changes. Therefore these cycles should indicate how sea level has affected the slope development and thus platform-margin evolution during this period. Through detailed, high-resolution sequence stratigraphy of the Great Bahama Bank's leeward margin, obtained via delta18O isotope and mineralogical (XRD) analyses, confined by U/Th dating and nannofossil bioevents, a greater understanding of the bedding geometries within the Pleistocene-Holocene seismic sequences and clues as to the nature of the slope development has been achieved. The high-resolution seismic profiles indicate that since the Plio-Pleistocene change in geometry, in which the Great Bahama Bank developed into a rimmed platform, continued steepening and subsequent progradation of the leeward margin has typified slope development during the Quaternary, which is described as an accretionary slope. However, on the basis of our observations we conclude that only the early to lower middle Pleistocene section (isotope stages 45-20) and the Holocene (isotope stage 1) of the leeward margin is accretionary. This indicates that a degree of erosion and/or by-passing has occurred on the leeward margin since the lower middle Pleistocene (isotope stage 19). During the first part of this period (isotope stages 19-12) erosion and/or by-passing occurred in the middle to lower slope regions and toe-of-slope. By the end of the upper middle to late Pleistocene phase (isotope stages 11-2) erosion also occurred on the upper slope. This erosion by currents at the toe-of-slope and oversteepening of the upper and middle slopes have led to back-cutting upslope and resulted in the progressive retreat of the toe-of-slope towards the platform to the east. However, the rise in sea level since the Last Glacial Maximum to its present-day level has allowed high productivity on the platform top during the Holocene and the deposition of a thick sediment wedge on the slope and sedimentation across the entire leeward flanks. This has led to the redevelopment of an accretionary slope and continued westward progradation of the Great Bahama Bank's western, leeward margin.

Diffusion Tensor Imaging in Alzheimer's disease

Attentional control and Information processing speed are central concepts in cognitive psychology and neuropsychology. Functional neuroimaging and neuropsychological assessment have depicted theoretical models considering attention as a complex and non-unitary process. One of its component processes, Attentional set-shifting ability, is commonly assessed using the Trail Making Test (TMT). Performance in the TMT decreases with increasing age in adults, Mild Cognitive Impairment (MCI) and Alzheimer’s Disease (AD). Besides, speed of information processing (SIP) seems to modulate attentional performance. While neural correlates of attentional control have been widely studied, there are few evidences about the neural substrates of SIP in these groups of patients. Different authors have suggested that it could be a property of cerebral white matter, thus, deterioration of the white matter tracts that connect brain regions related to set-shifting may underlie the age-related, MCI and AD decrease in performance. The aim of this study was to study the anatomical dissociation of attentional and speed mechanisms. Diffusion tensor imaging (DTI) provides a unique insight into the cellular integrity of the brain, offering an in vivo view into the microarchitecture of cerebral white matter. At the same time, the study of ageing, characterized by white matter decline, provides the opportunity to study the anatomical substrates speeded or slowed information processing. We hypothesized that FA values would be inversely correlated with time to completion on Parts A and B of the TMT, but not the derived scores B/A and B-A.

Structural changes after videogame practice related to a brain network associated with intelligence

Here gray and white matter changes after four weeks of videogame practice were analyzed using optimized voxel-based morphometry (VBM), cortical surface and cortical thickness indices, and white matter integrity computed from several projection, commissural, and association tracts relevant to cognition. Beginning with a sample of one hundred young females, twenty right handed participants were recruited for the study and assigned to a practice or a control group carefully matched by their general cognitive ability scores. After the first scan, the practice group played ‘Professor Layton and The Pandora's Box’ 4 h per week during four weeks. A second scan was obtained at the end of practice and intelligence was measured again. Image analyses revealed gray and white matter changes in the practice group. Gray matter changes theoretically relevant for intelligence were observed for the practice group mainly in frontal clusters (Brodmann areas 9 and 10) and also in smaller parietal and temporal regions. White matter findings were focused in the hippocampal cingulum and the inferior longitudinal fasciculus. These gray and white matter changes presumably induced by practice did not interact with intelligence tests' scores.

MEG networks organization is related to white matter integrity

Many studies have assessed the characterization of anatomical or functional connectivity in mild cognitive impairment (MCI), however it is still unknown how they are related in the course of the pathology. Here we integrate the analysis of magnetoencephalographic (MEG) data with white matter (WM) integrity quantification from diffusion weighted imaging (DWI), to asses whether the damage in the WM tracts disrupt the organization of the functional networks.

The default mode network is functionally and structurally disrupted in amnestic mild cognitive impairment — a bimodal MEG–DTI study

Over the past years, several studies on Mild Cognitive Impairment (MCI) and Alzheimer's disease (AD) have reported Default Mode Network (DMN) deficits. This network is attracting increasing interest in the AD community, as it seems to play an important role in cognitive functioning and in beta amyloid deposition. Attention has been particularly drawn to how different DMN regions are connected using functional or structural connectivity. To this end, most studies have used functional Magnetic Resonance Imaging (fMRI), Positron Emission Tomography (PET) or Diffusion Tensor Imaging (DTI). In this study we evaluated (1) functional connectivity from resting state magnetoencephalography (MEG) and (2) structural connectivity from DTI in 26 MCI patients and 31 age-matched controls. Compared to controls, the DMN in the MCI group was functionally disrupted in the alpha band, while no differences were found for delta, theta, beta and gamma frequency bands. In addition, structural disconnection could be assessed through a decreased fractional anisotropy along tracts connecting different DMN regions. This suggests that the DMN functional and anatomical disconnection could represent a core feature of MCI.

Natural and experimental oral infection of nonhuman primates by bovine spongiform encephalopathy agents

Experimental lemurs either were infected orally with the agent of bovine spongiform encephalopathy (BSE) or were maintained as uninfected control animals. Immunohistochemical examination for proteinase-resistant protein (prion protein or PrP) was performed on tissues from two infected but still asymptomatic lemurs, killed 5 months after infection, and from three uninfected control lemurs. Control tissues showed no staining, whereas PrP was detected in the infected animals in tonsil, gastrointestinal tract and associated lymphatic tissues, and spleen. In addition, PrP was detected in ventral and dorsal roots of the cervical spinal cord, and within the spinal cord PrP could be traced in nerve tracts as far as the cerebral cortex. Similar patterns of PrP immunoreactivity were seen in two symptomatic and 18 apparently healthy lemurs in three different French primate centers, all of which had been fed diets supplemented with a beef protein product manufactured by a British company that has since ceased to include beef in its veterinary nutritional products. This study of BSE-infected lemurs early in their incubation period extends previous pathogenesis studies of the distribution of infectivity and PrP in natural and experimental scrapie. The similarity of neuropathology and PrP immunostaining patterns in experimentally infected animals to those observed in both symptomatic and asymptomatic animals in primate centers suggests that BSE contamination of zoo animals may have been more widespread than is generally appreciated.

Orientation-dependent and sequence-specific expansions of CTG/CAG trinucleotide repeats in Saccharomyces cerevisiae

A quantitative and selective genetic assay was developed to monitor expansions of trinucleotide repeats (TNRs) in yeast. A promoter containing 25 repeats allows expression of a URA3 reporter gene and yields sensitivity to the drug 5-fluoroorotic acid. Expansion of the TNR to 30 or more repeats turns off URA3 and provides drug resistance. When integrated at either of two chromosomal loci, expansion rates were 1 × 10−5 to 4 × 10−5 per generation if CTG repeats were replicated on the lagging daughter strand. PCR analysis indicated that 5–28 additional repeats were present in 95% of the expanded alleles. No significant changes in CTG expansion rates occurred in strains deficient in the mismatch repair gene MSH2 or the recombination gene RAD52. The frequent nature of CTG expansions suggests that the threshold number for this repeat is below 25 in this system. In contrast, expansions of the complementary repeat CAG occurred at 500- to 1,000-fold lower rates, similar to a randomized (C,A,G) control sequence. When the reporter plasmid was inverted within the chromosome, switching the leading and lagging strands of replication, frequent expansions were observed only when CTG repeats resided on the lagging daughter strand. Among the rare CAG expansions, the largest gain in tract size was 38 repeats. The control repeats CTA and TAG showed no detectable rate of expansions. The orientation-dependence and sequence-specificity data support the model that expansions of CTG and CAG tracts result from aberrant DNA replication via hairpin-containing Okazaki fragments.