Topographic Levels Research Articles

High and Low Stimulus-Driven Conflict Engage Segregated Brain Networks, Not Quantitatively Different Resources

Task-irrelevant information is constantly present in our environment and may interfere with the processing of the information necessary to achieve goal-directed behavior. While task goals determine which information must be suppressed, the demand for inhibitory control depends on the strength of the interference induced by incoming, task-irrelevant information. Whether the same or distinct inhibitory processes are engaged to suppress various degrees of interference from task-irrelevant information remains largely unresolved. We investigated this question by manipulating the strength of the conflict induced by automatic word reading in a classical color Stroop task. High conflict was induced by presenting words in participant's native language and low conflict by presenting words in a less familiar language. Behavioral performance and electrical neuroimaging analyses of event-related potentials to the words were analyzed following a two-by-two within-subject design with factors conflict strength (high; low) and color word/word ink congruency (congruent; incongruent). Behaviorally, we observed a significant conflict strength × congruency driven by a smaller Stroop effect in the low- than high conflict condition. Electrophysiologically, we observed a significant conflict strength × congruency interaction at the topographic level during the period of the N450 components, indicative of the engagement of distinct configurations of brain networks. No such interaction was found at the level of response strength. Electrical sources analyses localized the topographic effect within the anterior cingulate cortex and basal ganglia, left middle frontal and occipital areas. We interpret our results in terms of qualitatively distinct executive mechanisms for reactive inhibitory control in conditions of high versus low stimulus-driven conflict.

Estudo epidemiológico da síndrome da cauda equina

OBJECTIVE: The primary purpose of this study was to determine the characteristics and outcomes of the patients admitted at our clinics diagnosed with cauda equina syndrome (CES). Secondarily, this study will serve as a basis for other comparative studies aiming at a better understanding of this condition and its epidemiology. METHODS: We conducted a retrospective study by reviewing the medical records of patients diagnosed with CES and neurogenic bladder between 2005 and 2011. The following variables were analyzed: gender, age, etiology, topographic level of the lesion, time between disease onset and diagnosis, presence of neurogenic bladder, time between diagnosis and surgery, neurological damage and neurogenic bladder persistence. RESULTS: Considering that CES is a rare condition, we were not able to establish statistic correlation between the analyzed variables and the outcomes of the disease. However, this study brought to light the inadequacy of our public health system in treating that kind of patient. CONCLUSION: The study shows that despite the well-defined basis for managing CES, we noted a greater number of patients with sequels caused by this condition, than is seen in the literature. The delayed diagnosis and, consequently, delayed treatment, were the main causes for the results observed. Level of Evidence IV, Case Series.

Custos da irrigação e receita líquida do feijoeiro em um sistema pivô central sob variação do comprimento da tubulação de recalque e desnível topográfico

Neste trabalho, foi simulado o custo da irrigação de um sistema tipo pivô central com diferentes comprimentos da tubulação de recalque e desníveis topográficos na produção do feijoeiro comum, na região de Ilha Solteira -SP, bem como sua receita líquida. Considerou-se uma área irrigada pelo equipamento de 103,58 ha, sendo sua configuração a mais econômica possível para as variáveis consideradas. A participação da irrigação no custo de produção do feijoeiro variou de 14,8 a 21,5% entre as condições extremas, ou seja, do menor desnível topográfico (40 m) e comprimento da tubulação de recalque (2.000 m) ao maior desnível (80 m) e comprimento (3.000 m). Em todas as configurações do sistema de irrigação e com os preços praticados em agosto de 2008 ou com o preço histórico médio, seria viável a cultura do feijoeiro, proporcionando rendas líquidas de até R$ 3.959,64 ha-1 e até R$ 1.203,14 ha-1, respectivamente.

Estimation of Natural Recharge and Groundwater Build up in the Bandung Groundwater Basin Contributed from Rain Water Infiltration and Inter-aquifer Transfer

Bandung groundwater basin (GWB) is now in the serious crisis. It is basically composed of three aquifers, i.e.: (1) the uppermost unconfined aquifer, (2) the middle semi-confined aquifer and (3) the lower semi-confined aquifer. The groundwater (GW) crisis is due to over-exploitation especially from the middle semi-confined aquifer. In order to address the condition of GW resources in the region, estimation of GW recharge and GW build up are very important. This may help the GW management to overcome the present GW crisis. This paper will be devoted to share about the estimation of GW recharge and GW build up in the Bandung GWB contributed from direct rain water infiltration and inter-aquifer transfer that have been assessed by means of GW modeling. The 1st recharge can be assossiated with the vertical GW movement in the unsaturated zone, while the 2nd recharge was considered to be related with the GW flow in saturated intermediate to regional flow. The 1st recharge generally occures in the topographical high surrounding the Bandung basin, while the 2nd type can be predicted to occur along the GW flow path, i.e in the topographical high as well as in the regional GW flow. The 1st recharge would result in shallow GW system in the uppermost unconfined aquifer, while the 2nd recharge will result in the leakage into the middle semi- confined aquifer that is the most critical aquifer in the Bandung GWB.The conceptual model of natural recharge mechanism in the Bandung GWB was based on the model of natural recharge in the mountain front basin from Wilson (1980). The GW recharge and build up can be approached using GW modeling. The 1st component has been estimated based on 1D model of Richards (1931), whereas the estimation of 2nd component has been carried out based on aquifer leakage phanomen on the general 3D aquifer leakage model of Widodo et al (1999). Regional transfer between aquifers was performed by means of GW zone budgeting.Direct infiltration of rain water in Bandung GWB was estimated 5% of precipitation in the Bandung basin that builds up around 4.6 m3/sec additional GW. KBU is the most favourable GW recharge zone in Bandung GWB and contributes 2.6 m3/sec (57%) natural GW recharge, from KBS 1.5 m3/sec (32%) and from KBT 0.5 m3/sec (11%). In KBU the recharge zone was predicted at topographic level between 1000 and 1300 msl. The GW discharge zone in Bandung GWB can be attributed to the volcanic rocks at topographic level between 650 and 850 msl. The absolute discharge zone in the Bandung GWB is the River Citarum.

Variations in racemization/epimerization ratios and amino acid content of Glycymeris shells in raised marine deposits in the Mediterranean

In this study we compare the organic geochemistry of fossil and modern Glycymeris shells. Amino acids were preserved within the shells. The amino acid content of the shells was similar at all the sites studied. Amino acid racemization and epimerization of Glycymeris shells are suitable techniques for dating Pleistocene raised marine deposits. As reported in other studies, we found that isoleucine epimerization analysis has a greater capacity to discriminate between sites of different age than glutamic acid and aspartic acid. However, particular constraints regarding the use of amino acid dating concern intrashell variability, so to avoid divergent results, it is necessary to sample the same part of the shell, namely the complex cross lamellar region near the umbo. The dating of high-energy coastal marine deposits calls for extensive field work in order to ensure the collection of a large number of samples in order to obtain robust results and reject spurious values. Shell accumulations on the shore-line are conditioned by several factors. The high coefficients of variation for epimerization values and their distribution pattern can be attributed mainly to time-linked taphonomical processes (time-averaging) that gave rise to the shell-bearing bed. However, reworking from former highstand sea level deposits, which usually occupy higher topographic levels, is not a common occurrence. Therefore, as a result of time-averaging and post-depositional processes, it is difficult to identify substages in stacked shell beds in raised beach deposits belonging to the same marine oxygen isotope stage by means of amino acid racemization/epimerization.

Protocolo diagnóstico y tratamiento de la trombosis portal no cirrótica

Vascular disorders of the liver represent a heterogeneous group of diseases characterized by the frequent presence of a prothrombotic condition. Primary Budd-Chiari syndrome is characterized by the obstruction of the hepatic vein drainage at any topographical level. Clinical presentation is very heterogeneous ranging from the complete absence of symptoms to fulminant liver failure, depending on thrombosis extension, velocity of the appearance and on the development of compensatory mechanisms like formation of collateral vessels. Portal vein thrombosis is usually the consequence of a combination of local and systemic risk factors, and its manifestations differ in acute or chronic thrombosis. In both cases diagnosis is based on the demonstration of the venous obstruction usually by imaging like abdominal ultrasound or CT scan. The main goal of therapy is to provide vessel recanalization and/or decompression of the affected vascular bed.

Protocolo diagnóstico y tratamiento del síndrome de Budd-Chiari primario

Vascular disorders of the liver represent a heterogeneous group of diseases characterized by the frequent presence of a prothrombotic condition. Primary Budd-Chiari syndrome is characterized by the obstruction of the hepatic vein drainage at any topographical level. Clinical presentation is very heterogeneous ranging from the complete absence of symptoms to fulminant liver failure, depending on thrombosis extension, velocity of the appearance and on the development of compensatory mechanisms like formation of collateral vessels. Portal vein thrombosis is usually the consequence of a combination of local and systemic risk factors, and its manifestations differ in acute or chronic thrombosis. In both cases diagnosis is based on the demonstration of the venous obstruction usually by imaging like abdominal ultrasound or CT scan. The main goal of therapy is to provide vessel recanalization and/or decompression of the affected vascular bed.

The evolution of the high‐elevated depocenters of the northern Sierras Pampeanas (ca. 28˚ SL), Argentine broken foreland, South‐Central Andes: the Pipanaco Basin

AbstractThe Pipanaco Basin, in the southern margin of the Andean Puna plateau at ca. 28°SL, is one of the largest and highest intermontane basins within the northernmost Argentine broken foreland. With a surface elevation >1000 m above sea level, this basin represents a strategic location to understand the subsidence and subsequent uplift history of high‐elevation depositional surfaces within the distal Andean foreland. However, the stratigraphic record of the Pipanaco Basin is almost entirely within the subsurface, and no geophysical surveys have been conducted in the region. A high‐resolution gravity study has been designed to understand the subsurface basin geometry. This study, together with stratigraphic correlations and flexural and backstripping analysis, suggests that the region was dominated by a regional subsidence episode of ca. 2 km during the Miocene‐Pliocene, followed by basement thrusting and ca. 1–1.5 km of sediment filling within restricted intermontane basin between the Pliocene‐Pleistocene. Based on the present‐day position of the basement top as well as the Neogene‐Present sediment thicknesses across the Sierras Pampeanas, which show slight variations along strike, sediment aggradation is not the most suitable process to account for the increase in the topographic level of the high‐elevation, close‐drainage basins of Argentina. The close correlation between the depth to basement and the mean surface elevations recorded in different swaths indicates that deep‐seated geodynamic process affected the northern Sierras Pampeanas. Seismic tomography, as well as a preliminary comparison between the isostatic and seismic Moho, suggests a buoyant lithosphere beneath the northern Sierras Pampeanas, which might have driven the long‐wavelength rise of this part of the broken foreland after the major phase of deposition in these Andean basins.

Многолетняя динамика и гибель растительности маршей Колоколковой губы Баренцева моря

The satellite images show that the area of marshes in the Kolokolkova bay was notstable during the period from 1973 up to 2011. Until 2010 it varied from 357 to 636 ha. After a severe storm happened on July 24–25, 2010 the total area of marshes was reduced up to 43–50 ha. The mean value of NDVI for studied marshes, reflecting the green biomass, varied from 0.13 to 0.32 before the storm in 2010, after the storm the NDVI decreased to 0.10, in 2011 — 0.03. A comparative analysis of species composition and structure of plant communities described in 2002 and 2011, allowed to evaluate the vegetation changes of marshes of the different topographic levels. They are fol­lowing: a total destruction of plant communities of the ass. Puccinellietum phryganodis and ass. Caricetum subspathaceae on low and middle marches; increasing role of halophytic species in plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. typicum on middle marches; some changes in species composition and structure of plant communities of the ass. Caricetum glareosae vic. Calamagrostis deschampsioides subass. festucetosum rubrae on high marches and ass. Parnassio palustris–Salicetum reptantis in transition zone between marches and tundra without changes of their syntaxonomy; a death of moss cover in plant communities of the ass. Caricetum mackenziei var. Warnstorfia exannulata on brackish coastal bogs. The possible reasons of dramatic vegetation dynamics are discussed. The dating of the storm makes it possible to observe the directions and rates of the succession of marches vegetation.

Insediamento, territorio e formule notarili: una verifica (Verona, IX-XII secolo)

The organization of rural areas in early Middle Ages and its observability through techniques of location taken by notaries is a classic italian subject in the historiography in the second half of the 20th century. The documentation produced in Verona lend to a verify of the ipothesis and to the formulation of guidelines for the interpretation of this formulas as concerning settlement and village territory. The number of documents produced and preserved in Verona between 9th and 12th century, and its homogeneity as institutions which produced and trasmitted them, allows to deal with a complex analysis that must consider several others variables. On the hand of documentation it deals with the possible variety, up to personal practice, of notary’s formulas and uses; these are then linked on to differences on geographic patterns, ownership relations, landlords presence and agrarian practices. The variety of geographical context, equally divided between a hill of significant size, a dry and irrigated high plain and the lowlands subject to flood, is proposed as a positive element to identify different factors in the building of rural settlement, its organization and rapresentations. It is assumed that these formulas are developed into patterns resulting by a dialectic between notary’s culture and perception of the space organization, which should be the resulting in the relationship between human communities and the territory where these act. The aim is highlighting factors which were found to underlie the formation of village territories. This is the level more elusive and less considered by italian historiography that has traditionally focused on the jurisdictional (both landlord and ecclesiastical) or fiscal one and therefore the relationship between power and territory. The comparative reading of location practice as a system of relations between the words – elaborated by a topographic level diachronic as well as synchronous – allows instead to highlight their links with the different practices in the territory: not only through the presence of landlordship, but also the structure of habitat, the forms of solidarity and the access to common resources.

Influence of a topographic gradient on the occurrence, abundance and composition of nine species of palms (Arecaceae) in the Central Amazon

The study was conducted at the Adolpho Ducke Forest Reserve. The occurrence and abundance of the adult palms Attalea attaleoides (Barb. Rodr.) W Boer, A. microcarpa Mart., Euterpe precatoria Mart., Geonoma aspidiifolia Spruce, Iriartella setigera (Mart.) H. Wendl, Oenocarpus bacaba Mart., O. bataua Mart., O. minor Mart., Socratea exorrhiza (Mart.) H. Wendl were observed in 40 50 x 50 m plots and the seedlings in two 50 x 2 m plots located inside the 40 plots demarcated to register the adults. The topographical gradient was divided into swamp valley, slope and plateau based on the altitudes and characteristics of these environments. Occurrence and abundance data were used as dependent variables in the models of Analysis of Variance to verify differences in the topographical gradient. Changes in species composition were evaluated using multivariate analysis of ordination. The distribution and abundance of the seedling and adult phases varied with the topographical gradient. The variation in species composition in different topographic levels probably occurs due to the different responses of the species to the variation in forest heterogeneity, produced by the spatial variation of the structural components of the forest. Key words: palms, Central Amazon, topography, distribution, “Terra Firme” forest.

Maturity of central Madagascar's landscape — Low-temperature thermochronological constraints

Low-temperature thermochronological data from two profiles across central Madagascar give apatite fission track and apatite (U–Th)/He ages ranging between 258Ma and 176Ma and from 239Ma to 48Ma, respectively. Thermal models derived from these data, as well as modelling of basement denudation and the sedimentary record, indicate that first order topography of central Madagascar developed mainly due to flexural uplift during Mesozoic times. This was in response to successive erosion and depositional loading associated with the sedimentation in the Morondava and Majunga basins, both of which are now exposed along the western margin of Madagascar. Our data suggest that the eastern margin of the island had a similar denudation history and was probably at a similar topographic level before the late Cretaceous break-up of Madagascar and the India/Seychelles block. Cretaceous normal faulting, without major amounts of denudation, led to the development of the present east coast topography defined by a tectonically juvenile escarpment. In the centre of the island Cenozoic tectonics and volcanism has had a minor and localised influence on the landscape of central Madagascar.

Evidence for Pleistocene lakes in the Tushka region, south Egypt

Space Shuttle Radar Topography Mission (SRTM) data have revealed new details on the extent and geomorphic relations of paleodrainage in southern Egypt. Following a period of late Tertiary drainage from the Red Sea Hills south through Wadi Qena and west across the Tushka region, the Nile River as we now know it established its connections with Central Africa and the Mediterranean in the middle Pleistocene (oxygen isotope stage, OIS 7 to OIS 5). SRTM topography reveals a lake level at ∼247 m that is coincident with the elevation of middle Pleistocene fish fossils 400 km west of the Nile, and with the termination of shallow runoff channels in northern Sudan that were active during the middle Pleistocene and Holocene pluvial periods. An additional lake level at ∼190 m is based on the current elevation at Wadi Tushka, and is consistent with Paleolithic sites at Bir Kiseiba followed by Neolithic sites at lower topographic levels. Overflow of the Nile through Wadi Tushka during the wetter north African climate of the middle Pleistocene, coupled with limited local rainfall, was the likely source of water for these lakes.

Cost of irrigation and profit of bean in a center pivot system with water pumped by diesel engine under variation of length pressurized pipe and topographic levels

En este trabajo se estimo el costo de un sistema de riego con pivote central con bombeo por un motor diesel e realizados en diferentes longitudes de la tuberia de recalque y desnivel de la topografia en la produccion de frijol en la region de Ilha Solteira – SP, y sus ingresos netos. Se considero un area de riego de 103,58 hectareas, y la configuracion del sistema mas economico posible para las variables consideradas. La cuota de riego en el costo de produccion de granos vario desde 26,6 hasta 37,6% entre los extremos, es decir, la pendiente mas baja (40 m) y la longitud de la tuberia de recalque (2000 m) hasta la brecha mas grande (80 m) y longitud (3000 m). Teniendo en cuenta los precios en agosto de 2008 todos los ajustes del sistema de riego por gasoleo puedem ser viable y atractiva, proporcionando ingresos netos de hasta R$ 3,283.37 ha -1 . Para el precio promedio historico (en el periodo de agosto de 2001 a 2008), en las configuraciones despues de una longitud de 3000 metros de tuberias, la cosecha de frijol de riego se convierte en inviable, y las perdidas ascienden R$ 332.10 ha -1 .

Size variation of six species of oxudercine gobies along the intertidal zone in a Malayan coastal swamp

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 409:199-212 (2010) - DOI: https://doi.org/10.3354/meps08597 Size variation of six species of oxudercine gobies along the intertidal zone in a Malayan coastal swamp G. Polgar1,*, V. Bartolino2 1Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia 2Institute of Marine Research, Swedish Board of Fisheries, Lysekil, Sweden *Email: gianluca.polgar@gmail.com ABSTRACT: Reduction in size from sea to land is a common trend of many fish species and communities, at both the intraspecific and interspecific level. Within the intertidal zone, similar trends have been described at the intraspecific level in several transient and resident fish species. Oxudercines are a group of intertidal gobies (Gobiidae: Oxudercinae) including several species, which exhibit extreme adaptations to an amphibious lifestyle. Ecomorphological and ecophysiological considerations suggest that size reduction in this group may have facilitated the adaptation to semi-terrestrial conditions. To test this hypothesis, the spatial ecology and the presence of an intra- and interspecific size gradient was investigated in an oxudercine community of a Malayan intertidal ecosystem (6 species included in 3 genera). A random stratified sampling design was adopted, and ANOVA and cluster analysis performed to describe this variation. Multivariate analyses of the quantity of environmental water were also conducted to investigate the correspondence between size and habitat terrestriality. Larger species were found in more aquatic conditions at lower topographical levels along the vertical intertidal gradient, supporting the hypothesis of an adaptive value of smaller size in more terrestrial habitats. Intraspecific variation showed more complex patterns, even if in several species smaller individuals were found in more terrestrial conditions. KEY WORDS: Intertidal fishes · Size distribution · Habitat partitioning · Spatial ecology · Tropical · Mudskippers · Amphibious fishes · Water to land eco-evolutionary transition Full text in pdf format Supplementary material PreviousNextCite this article as: Polgar G, Bartolino V (2010) Size variation of six species of oxudercine gobies along the intertidal zone in a Malayan coastal swamp. Mar Ecol Prog Ser 409:199-212. https://doi.org/10.3354/meps08597Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 409. Online publication date: June 23, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.

Mapping Medusae Fossae Formation materials in the southern highlands of Mars

The Medusae Fossae Formation (MFF) is an extensive deposit (2.2 × 10 6 km 2, Bradley, B.A., Sakimoto, S.E.H., Frey, H., Zimbelman, J.R. [2002]. J. Geophys. Res. 107, 5058) of wind-eroded material of widely debated origin, which unconformably overlies a considerable area of the crustal dichotomy boundary on Mars. The MFF shows a variety of layering patterns, erosional styles and channel-like forms and has been mapped into five main outcrops and three geological members according to exposure and stratigraphy (Scott, D.H., Tanaka, K.L., 1986. USGS Map I-1802-A; Greeley, R., Guest, J.E., 1987. Map I-1802-B; Zimbelman, J.R., Crown, D., Jenson, D., 1996. Lunar Planet. Sci. XXVII. Abstract #1748.). Away from the three main lobes are numerous outliers of MFF materials. These have mainly been reported in the northern lowlands regions (Keszthelyi, L., Jaeger, W.L., and HiRISE team, 2008. Lunar Planet. Sci. XXXIX. Abstract #2420.) but few studies have examined the possibility of MFF outliers on high ground south of the dichotomy boundary. We have searched Mars Orbiter Camera Narrow Angle (MOC NA) images for outliers in this region. Our observations show that there are many MFF outliers on the southern highlands. The characteristics of the outliers indicate materials which overlie the underlying terrain for they appear widely in dips, craters and topographic lows. The surfaces are typified by yardang fields and have a similar patchy and discontinuous nature to materials of the upper member of the MFF. Most have consistent lineation orientations across the wider area which match the dominant orientation of yardangs in the main MFF outcrops. Furthermore, elevation data shows that the maximum, minimum and mean elevations of these newly discovered outliers are closest to those of the upper member of the MFF. We therefore conclude that these deposits are MFF outliers and that they probably represent remnant upper member material. We suggest that there might be two possible explanations for these outliers: (1) the MFF had a much greater pre-erosional extent than previously estimated, or (2) materials from the main outcrops were eroded and then blown south to accrue in the highland areas, where they were subsequently reworked. We suggest that the topography of the region favors the first option. We outline an “overflowing” layer-cake deposition model, in which layers of sediment stacked up against the dichotomy boundary until they reached the topographic level of the highlands. Further materials (that went onto become upper-member MFF material and outliers) were then deposited across a wider area, including south of the dichotomy boundary. Severe erosion subsequently removed much of this material.

Modeling decay rates of dead wood in a neotropical forest

Variation of dead wood decay rates among tropical trees remains one source of uncertainty in global models of the carbon cycle. Taking advantage of a broad forest plot network surveyed for tree mortality over a 23-year period, we measured the remaining fraction of boles from 367 dead trees from 26 neotropical species widely varying in wood density (0.23-1.24 g cm(-3)) and tree circumference at death time (31.5-272.0 cm). We modeled decay rates within a Bayesian framework assuming a first order differential equation to model the decomposition process and tested for the effects of forest management (selective logging vs. unexploited), of mode of death (standing vs. downed) and of topographical levels (bottomlands vs. hillsides vs. hilltops) on wood decay rates. The general decay model predicts the observed remaining fraction of dead wood (R2 = 60%) with only two biological predictors: tree circumference at death time and wood specific density. Neither selective logging nor local topography had a differential effect on wood decay rates. Including the mode of death into the model revealed that standing dead trees decomposed faster than downed dead trees, but the gain of model accuracy remains rather marginal. Overall, these results suggest that the release of carbon from tropical dead trees to the atmosphere can be simply estimated using tree circumference at death time and wood density.

Subtle topographical differences along a floodplain promote different plant strategies among Paspalum dilatatum subspecies and populations

AbstractIt was hypothesised that subtle topographical differences might cause the existence of ecotypes along a floodplain. The apomict grass Paspalum dilatatum subspecies dilatatum inhabits flood‐prone lowlands as well as nearby uplands in the floodplains of Argentina, while the sexual P. dilatatum subspecies flavescens almost exclusively inhabits the uplands. The aim of the present study was to identify the different traits that allow these P. dilatatum populations to inhabit different habitats. Plants of P. dilatatum were reciprocally transplanted between uplands and lowlands. Morphophysiological traits related to flooding tolerance were measured during a flood. Subspecies dilatatum from the uplands and subspecies flavescens showed a high physiological performance in the uplands but a considerable decrease in stomatal conductance, net photosynthesis rates and tiller number in the flooded lowlands. In contrast, the subspecies dilatatum from the lowlands showed relatively lower and stable stomatal conductance, photosynthesis rates and leaf water potential at both sites. Subspecies dilatatum from the lowlands outperformed upland populations at the lowland site with respect to tillering. Leaves of subspecies dilatatum from the lowlands that had grown at the lowland habitat had a lower blade/sheath proportion than leaves of plants transplanted to the uplands. This behavior did not occur in both upland populations. Results suggest that dilatatum Lowland plants have the typical strategy of stress‐tolerant genotypes and that the upland populations are adapted to habitats where competitive species are selected. In conclusion, habitats with subtle differences in topographic level can favour both ecotypic differentiations within an apomict subspecies but also the maintenance of morphophysiological similitudes between coexisting upland populations belonging to different subspecies.

A realistic inversion algorithm for magnetic anomaly data: the Mt. Amiata volcano test

The aim of this work is the formulation of a 3D model of the Mt. Amiata volcanic complex (Southern Tuscany) by means of geomagnetic data. This work is shown not only as a real test to check the validity of the inversion algorithm, but also to add information about the structure of the volcanic complex. First, we outline briefly the theory of geomagnetic data inversion and we introduce the approach adopted. Then we show the 3D model of the Amiata volcano built from the inversion, and we compare it with the available geological information. The most important consideration regards the surface distribution of the magnetization that is in good agreement with rock samples from this area. Moreover, the recovered model orientation recall the extension of the lava flows, and as a last proof of validity, the source appears to be contained inside of the topographic contour level. The credibility of the inversion procedure drives the interpretation even for the deepest part of the volcano. The geomagnetic signal appears suppressed at a depth of about 2 km, but the most striking consequence is that sub-vertical structures are found even in different positions from the conduits shown in the geologic sections. The results are thus in good agreement with the information obtained from other data, but showing features that had not been identified, stressing the informative power of the geomagnetic signal when a meaningful inversion algorithm is used.

Evidence for multiple ice deposits on the northeastern rim of Hellas basin, Mars

Four prominent fluvial systems, Dao, Niger, and Harmakhis Valles, and a system of smaller channels between Niger and Harmakhis Valles characterize a wide topographic trough that connects Hesperia Planum and Hellas Planitia (Hesperia–Hellas trough, HHT). The source depressions of the canyons of Dao and Harmakhis Valles are at the lowermost level (about − 5.4 km and lower), the system of Niger Vallis is at medium elevation (about − 3 to − 4 km), and the small channels occur at the highest topographic levels (about − 2.5 to − 3.2 km). All systems are among the youngest features in the region. They formed due to the release of subsurface water and apparently have their sources at different topographic levels below or within the layered suite of volcanic deposits in HHT. Two scenarios can explain the subsurface nature of their sources: (1) flow of liquid ground water from extensive watershed toward the source areas and accumulation of water there and (2) deposition of ice-bearing materials in and around the sources. The first scenario requires the existence of extensive confining layers at different topographic levels corresponding to the levels of the floors of the canyons/channels. Because the presence of such confining layers on Mars is problematic, we consider the first scenario to be less likely. We believe that the deposition of ice-bearing materials at different levels during the growth of the lava plateau in HHT can better explain the key features of the fluvial systems: the subsurface nature of the sources and the relatively young age. In this scenario, the higher topographic position of the ice-bearing deposits corresponds to the younger age of deposition. The possible accumulations of ice were buried by successive volcanic deposits, including lava flows in HHT and later were heated from below by magmatic intrusions that caused melting of the icy deposits, release of water, and formation of the fluvial structures.