Revealing regional deforestation dynamics in north-eastern Madagascar - Insights from multi-temporal land cover change analysis

The north-eastern escarpment of Madagascar harbours the island’s last remaining large-scale humid forest massifs surrounded by a small-scale agricultural mosaic. There is high deforestation, commonly thought to be caused by shifting cultivation practiced by local land users to produce upland rice. However, little is known about the dynamics between forest and shifting cultivation systems at a regional level. Our study presents a first attempt to quantify changes in the extent of forest and different agricultural land cover classes, and to identify the main dynamics of land cover change for two intervals, 1995–2005 and 2005–2011. Over the 16-year study period, the speed of forest loss increased, the total area of upland rice production remained almost stable, and the area of irrigated rice fields slightly increased. While our findings seem to confirm a general trend of land use intensification, deforestation through shifting cultivation is still on the rise. Deforestation mostly affects the small forest fragments interspersed in the agricultural mosaic and is slowly leading to a homogenization of the landscape. These findings have important implications for future interventions to slow forest loss in the region, as the processes of agricultural expansion through shifting cultivation versus intensified land use cannot per se be considered mutually exclusive.

37,X/38,XY Mosaicism in a Cryptorchid Bengal Cat with Müllerian Duct Remnants

A 23-month-old tomcat was referred to our clinic because of male behavioral problems, cryptorchidism, and an undefined intra-abdominal organ resembling a uterus. Ultrasonography and computed tomography showed 2 fluid-filled tubular structures dorsolaterally to the bladder and connected to the pelvic urethra. The cat was castrated, and the tubular structures were surgically removed. Histology identified them as Müllerian duct remnants. The testes were hypoplastic, the epididymes and deferent ducts were normal. Cytogenetic analyses revealed the presence of a mosaic 37,X/38,XY karyotype which explains the clinical findings.

Expression of a bacterial serine acetyltransferase in transgenic potato plants leads to increased levels of cysteine and glutathione

The coding sequence of the wild-type, cys-sensitive, cysE gene from Escherichia coli, which encodes an enzyme of the cysteine biosynthetic pathway, namely serine acetyltransferase (SAT, EC 2.3.1.30), was introduced into the genome of potato plants under the control of the cauliflower mosaic virus 35S promoter. In order to target the protein into the chloroplast, cysE was translationally fused to the 5′-signal sequence of rbcS from Arabidopsis thaliana. Transgenic plants showed a high accumulation of the cysE mRNA. The chloroplastic localisation of the E. coli SAT protein was demonstrated by determination of enzymatic activities in enriched organelle fractions. Crude leaf extracts of these plants exhibited up to 20-fold higher SAT activity than those prepared from wild-type plants. The transgenic potato plants expressing the E. coli gene showed not only increased levels of enzyme activity but also exhibited elevated levels of cysteine and glutathione in leaves. Both were up to twofold higher than in control plants. However, the thiol content in tubers of transgenic lines was unaffected. The alterations observed in leaf tissue had no effect on the expression of O-acetylserine(thiol)-lyase, the enzyme which converts O-acetylserine, the product of SAT, to cysteine. Only a minor effect on its enzymatic activity was observed. In conclusion, the results presented here demonstrate the importance of SAT in plant cysteine biosynthesis and show that production of cysteine and related sulfur-containing compounds can be enhanced by metabolic engineering.

Pond-Breeding Amphibian Species Distributions in a Beaver-Modified Landscape, Acadia National Park, Mount Desert Island, Maine

In order to maintain pond-breeding amphibian species richness, it is important to understand how both natural and anthropogenic disturbances affect species assemblages and individual species distributions both at the scale of individual ponds and at a larger landscape scale. The goal of this project was to investigate what characteristics of ponds and the surrounding wetland landscape were most effective in predicting pond-breeding species richness and the individual occurrence of wood frog (Rana sylvatica), bullfrog (Rana catesbeiana) and pickerel frog (Rana palustris) breeding sites in a beaver-modified landscape and how this landscape has changed over time. The wetland landscape of Acadia National Park was historically modified by the natural disturbance cycles of beaver (Castor cazadensis), and since their reintroduction to the island in 1921, beaver have played a large role in creating and maintaining palustrine wetlands. In 2000 and 2001, I studied pond-breeding amphibian assemblages at 71 palustrine wetlands in Acadia National Park, Mount Desert Island, Maine. I determined breeding presence of 7 amphibian species and quantified 15 variables describing local pond conditions and characteristics of the wetland landscape. I developed a priori models to predict sites with high amphibian species and used model selection with Akaike's Information Criterion (AIC) to identify important variables. Single species models were also developed to predict wood frog, bullfrog and pickerel frogs breeding presence. The variables for wetland connectivity by stream corridors and the presence of beaver disturbance were the most effective variables to predict sites with high amphibian richness. Wood frog breeding was best predicted by local scale variables describing temporary, fishless wetlands and the absence of active beaver disturbance. Abandoned beaver sites provided wood frog breeding habitat (70%) in a similar proportion to that found in non beaver-influenced sites (79%). In contrast, bullfrog breeding presence was limited to active beaver wetlands with fish and permanent water, and 80% of breeding sites were large (≥2ha in size). Pickerel frog breeding site selection was predicted best by the connectivity of sites in the landscape by stream corridors. Models including the presence of beaver disturbance, greater wetland perimeter and greater depth were included in the confidence set of pickerel frog models but showed considerably less support. Analysis of historic aerial photographs showed an 89% increase in the total number of ponded wetlands available in the landscape between the years of 1944 and 1997. Beaver colonization generally converted forested wetlands and riparian areas to open water and emergent wetlands. Temporal colonization of beaver wetlands favored large sites low in the watersheds and sites that were impounded later were generally smaller, higher in the watershed, and more likely to be abandoned. These results suggest that beaver have not only increased the number of available breeding sites in the landscape for pond-breeding amphibians, but the resulting mosaic of active and abandoned beaver wetlands also provides suitable breeding habitat for species with differing habitat requirements.

Analysis of the E1-ubiquitin activating enzyme, Uba1, in cell death and tissue growth in Drosophila

Ubiquitination is an essential process involved in basic biological processes such as the cell cycle and cell death. Ubiquitination is initiated by ubiquitin-activating enzymes (E1), which activate and transfer ubiquitin to ubiquitin-conjugating enzymes (E2). Subsequently, ubiquitin is transferred to target proteins via ubiquitin ligases (E3). Defects in ubiquitin conjugation have been implicated in several forms of malignancy, the pathogenesis of several genetic diseases, immune surveillance/viral pathogenesis, and the pathology of muscle wasting. However, the consequences of partial or complete loss of ubiquitin conjugation in multi-cellular organisms are not well understood. Here, we report the characterization of nba1, the sole E1 in Drosophila. We have determined that weak and strong nba1 alleluias behave genetically different and sometimes in opposing phenotypes. For example, weak uba1 alleluias protect cells from cell death whereas cells containing strong loss-of-function alleluias are highly apoptotic. These opposing phenotypes are due to differing sensitivities of cell death pathway components to ubiquitination level alterations. In addition, strong uba1 alleluias induce cell cycle arrest due to defects in the protein degradation of Cyclins. Surprisingly, clones of strong uba1 mutant alleluias stimulate neighboring wild-type tissue to undergo cell division in a non-autonomous manner resulting in severe overgrowth phenotypes in the mosaic fly. I have determined that the observed overgrowth phenotypes were due to a failure to downregulate the Notch signaling pathway in nba1 mutant cells. Aberrant Notch signaling results in the secretion of a local cytokine and activation of JAK/STAT pathway in neighboring cells. In addition, we elucidated a model describing the regulation of the caspase Dronc in surviving cells. Binding of Dronc by its inhibitor Diap1 is necessary but not sufficient to inhibit Dronc function. Ubiquitin conjugation and Uba1 function is necessary for the negative regulation of Dronc. ^

Prácticas políticas y tensiones internas en la experiencia peronista mendocina (1972-1974)

En el presente artículo se describen los factores que provocaron Ias rivalidades y tensiones internas en el Peronismo Mendocino, lo que causó la caída del gobierno de Alberto Martínez Baca - Carlos Mendoza. En este proceso se interrelacionan diferentes actores: la ofensiva extrapartidaria, el movimiento obrero, los jóvenes revolucionarios, los políticos verticalistas, etc. Para ello se comienza presentando el mosaico partidario mendocino en el proceso que desemboca en la transición democrática de 1973. Básicamente, se pone de manifiesto, la interacción entre el Partido Demócrata y el régimen militar, el sesgo moderado de la UCR local, y la conflictiva heterogeneidad del peronismo. Con grandes dificultades para solucionar sus diferencias a través de canales institucionales, pero al mismo tiempo con una dinámica de intensa politización. Por eso, se plantean algunas observaciones sobre las características de la radicalización juvenil, y, se ofrece una breve reconstrucción historiográfica del movimiento obrero mendocino desde una perspectiva de análisis que tiene en cuenta centralmente, dos aspectos: su relación con el liderazgo carismático de Perón, y su relación -ambivalente- con los gobiernos de la "Revolución Argentina". La búsqueda de la desperonización del país, la puja por tratar de captar los votos otrora peronistas, las ansias individuales al abrirse eI mercado eIectoral, la división de posiciones u opiniones frente a Ios gobiernos autoritarios, y la radicalización social, trajo aparejado una profundización de la crisis interna. Crisis que se vio reflejada en el proceso que condujo a la elección de Alberto Martínez Baca y Carlos Mendoza como candidatos a la gobernación, poniendo de manifiesto la influencia de los sectores identificados con el "peronismo revolucionario" y la ofensiva de la "derecha peronista". Su corolario: la intervención a los tres poderes de la provincia.

Proceso de expansión urbana, actores y desigualdades

Este artículo busca analizar el proceso de expansión urbana de la ciudad de San Carlos de Bariloche, desde un enfoque de la especialidad y la temporalidad, con miras a comprender, desde sus lógicas de crecimiento, el actual contexto de profunda desigualdad urbana. Los distintos actores hegemónicos, los cuales fueron cambiando a lo largo del tiempo, han marcado el pulso de la urbanización, la expansión del ejido municipal y la aprobación de los loteos que contribuyeron a un crecimiento acelerado, descontrolado y especulativo. Entre ellos se destaca el Estado que desde distintas esferas instituciones, jurisdiccionales y funcionales, ostenta con determinado protagonismo su rol doble como agente y árbitro. Este estudio se ha realizado a partir de un profundo rastreo y análisis de fuentes documentales, muchas inéditas, vinculadas al desarrollo urbano barilochense, desde su fundación en 1902 hasta 2010. Así, con rupturas y continuidades, el crecimiento de esta ciudad media da cuenta de la notable importancia del estudio de los factores que definen modelos de desarrollo urbanos para comprender la complejidad del mosaico urbano actual y su posible mejoramiento.

Age determination of Lake Melkoe sediments

The formation of Lake Melkoe (64°51'30''N, 175°14'E, altitude 36 m), one of the largest lakes of the Anadyr Lowland, is related to the moraine left by the Tyellakh Glacier, which originated on the Pekul'nei Ridge. The lake (6 km long and 4.4 km wide) extends in the northwestern direction. The Kholmy Priozernye moraine (16 km long along the arc, 1.5 km wide, and 92-103 masl) surrounds the lake in the west and south. The lake coasts are covered by sand with pebbles and shingle. The flat lake bottom dips toward its central part to a depth of 160 cm. In distinction from many other lakes of the Anadyr Lowland, the thickness of the upper layer of water-saturated sediments overlying compact aleurites in Lake Melkoe is only 5-6 cm. Such a peculiarity of the bottom is explained by the large size of the lake, low sedimentation rates, and frequent storms caused by strong winds. Regional and local vegetation corresponds to a mosaic tundra represented by high shrubs Pinus pumila, Duschekia fruticosa , and hummocky Betula - Ericales - Eriophorum communities. Pinus pumila and Alnus form thickets on the banks of the Anadyr River, coasts of lakes, and moraine slopes.

Digital elevation model (DEM) of the ice sheet in western Dronning Maud Land, Antarctica

In this paper, a new digital elevation model (DEM) is derived for the ice sheet in western Dronning Maud Land, Antarctica. It is based on differential interferometric synthetic aperture radar (SAR) from the European Remote Sensing 1/2 (ERS-1/2) satellites, in combination with ICESat's Geoscience Laser Altimeter System (GLAS). A DEM mosaic is compiled out of 116 scenes from the ERS-1 ice phase in 1994 and the ERS-1/2 tandem mission between 1996 and 1997 with the GLAS data acquired in 2003 that served as ground control. Using three different SAR processors, uncertainties in phase stability and baseline model, resulting in height errors of up to 20 m, are exemplified. Atmospheric influences at the same order of magnitude are demonstrated, and corresponding scenes are excluded. For validation of the DEM mosaic, covering an area of about 130,000 km**2 on a 50-m grid, independent ICESat heights (2004-2007), ground-based kinematic GPS (2005), and airborne laser scanner data (ALS, 2007) are used. Excluding small areas with low phase coherence, the DEM differs in mean and standard deviation by 0.5 +/- 10.1, 1.1 +/- 6.4, and 3.1 +/- 4.0 m from ICESat, GPS, and ALS, respectively. The excluded data points may deviate by more than 50 m. In order to suppress the spatially variable noise below a 5-m threshold, 18% of the DEM area is selectively averaged to a final product at varying horizontal spatial resolution. Apart from mountainous areas, the new DEM outperforms other currently available DEMs and may serve as a benchmark for future elevation models such as from the TanDEM-X mission to spatially monitor ice sheet elevation.

Gas emissions and ROV survey tracks of the Regab pockmark (Northern Congo Fan)

Pockmarks are seafloor depressions commonly associated with fluid escape from the seabed and are believed to contribute noticeably to the transfer of methane into the ocean and ultimately into the atmosphere. They occur in many different areas and geological contexts, and vary greatly in size and shape. Nevertheless, the mechanisms of pockmark growth are still largely unclear. Still, seabed methane emissions contribute to the global carbon budget, and understanding such processes is critical to constrain future quantifications of seabed methane release at local and global scales. The giant Regab pockmark (9°42.6' E, 5°47.8' S), located at 3160 m water depth near the Congo deep-sea channel (offshore southwestern Africa), was investigated with state-of-the-art mapping devices mounted on IFREMER's (French Research Institute for Exploitation of the Sea) remotely operated vehicle (ROV) Victor 6000. ROV-borne micro-bathymetry and backscatter data of the entire structure, a high-resolution photo-mosaic covering 105,000 m2 of the most active area, sidescan mapping of gas emissions, and maps of faunal distribution as well as of carbonate crust occurrence are combined to provide an unprecedented detailed view of a giant pockmark. All data sets suggest that the pockmark is composed of two very distinctive zones in terms of seepage intensity. We postulate that these zones are the surface expression of two fluid flow regimes in the subsurface: focused flow through a fractured medium and diffuse flow through a porous medium. We conclude that the growth of giant pockmarks is controlled by self-sealing processes and lateral spreading of rising fluids. In particular, partial redirection of fluids through fractures in the sediments can drive the pockmark growth in preferential directions.

Near-coastal circum-Antarctic iceberg size distributions determined from Synthetic Aperture Radar images

The Radarsat-1 Antarctic Mapping Project (RAMP) compiled a mosaic of Antarctica and the adjacent ocean zone from more than 3000 high-resolution Synthetic Aperture Radar (SAR) images acquired in September and October 1997. The mosaic with a pixel size of 100 m was used to determine iceberg size distributions around Antarctica, combining an automated detection with a visual control of all icebergs larger than 5 km**2 and correction of recognized false detections. For icebergs below 5 km**2 in size, the numbers of false detections and accuracies of size retrievals were analyzed for three test sites. Nearly 7000 icebergs with horizontal areas between 0.3 and 4717.7 km**2 were identified in a near-coastal zone of varying width between 20 and 300 km. The spatial distributions of icebergs around Antarctica were calculated for zonal segments of 20° angular width and related to the types of the calving fronts in the respective section. Results reveal that regional variations of the size distributions cannot be neglected. The highest ice mass accumulations were found at positions of giant icebergs (> 18.5 km) but also in front of ice shelves from which larger numbers of smaller icebergs calve almost continuously. Although the coastal oceanic zone covered by RAMP is too narrow compared to the spatial coverage needed for oceanographic research, this study nevertheless demonstrates the usefulness of SAR images for iceberg research and the need for repeated data acquisitions extending ocean-wards over distances of 500 km and more from the coast to monitor iceberg melt and disintegration and the related freshwater input into the ocean.

Per-field land use and land cover data set of the Haean catchment, South Korea

Detailed data on land use and land cover constitute important information for Earth system models, environmental monitoring and ecosystem services research. Global land cover products are evolving rapidly; however, there is still a lack of information particularly for heterogeneous agricultural landscapes. We censused land use and land cover field by field in the agricultural mosaic catchment Haean in South Korea. We recorded the land cover types with additional information on agricultural practice. In this paper we introduce the data, their collection and the post-processing protocol. Furthermore, because it is important to quantitatively evaluate available land use and land cover products, we compared our data with the MODIS Land Cover Type product (MCD12Q1). During the studied period, a large portion of dry fields was converted to perennial crops. Compared to our data, the forested area was underrepresented and the agricultural area overrepresented in MCD12Q1. In addition, linear landscape elements such as waterbodies were missing in the MODIS product due to its coarse spatial resolution. The data presented here can be useful for earth science and ecosystem services research.

Large-Area Photo-Mosaicking tool (LAPM tool)

This paper presents a new tool for large-area photo-mosaicking (LAPM tool). This tool was developed specifically for the purpose of underwater mosaicking, and it is aimed at providing end-user scientists with an easy and robust way to construct large photo-mosaics from any set of images. It is notably capable of constructing mosaics with an unlimited number of images on any modern computer (minimum 1.30 GHz, 2 GB RAM). The mosaicking process can rely on both feature matching and navigation data. This is complemented by an intuitive graphical user interface, which gives the user the ability to select feature matches between any pair of overlapping images. Finally, mosaic files are given geographic attributes that permit direct import into ArcGIS. So far, the LAPM tool has been successfully used to construct geo-referenced photo-mosaics with photo and video material from several scientific cruises. The largest photo-mosaic contained more than 5000 images for a total area of about 105,000 m**2. This is the first article to present and to provide a finished and functional program to construct large geo-referenced photo-mosaics of the seafloor using feature detection and matching techniques. It also presents concrete examples of photo-mosaics produced with the LAPM tool.

Satellite image map of King George Island, Antarctica

A new topographic database for King George Island, one of the most visited areas in Antarctica, is presented. Data from differential GPS surveys, gained during the summers 1997/98 and 1999/2000, were combined with up to date coastlines from a SPOT satellite image mosaic, and topographic information from maps as well as from the Antarctic Digital Database. A digital terrain model (DTM) was generated using ARC/INFO GIS. From contour lines derived from the DTM and the satellite image mosaic a satellite image map was assembled. Extensive information on data accuracy, the database as well as on the criteria applied to select place names is given in the multilingual map. A lack of accurate topographic information in the eastern part of the island was identified. It was concluded that additional topographic surveying or radar interferometry should be conducted to improve the data quality in this area. In three case studies, the potential applications of the improved topographic database are demonstrated. The first two examples comprise the verification of glacier velocities and the study of glacier retreat from the various input data-sets as well as the use of the DTM for climatological modelling. The last case study focuses on the use of the new digital database as a basic GIS (Geographic Information System) layer for environmental monitoring and management on King George Island.