Search

Copyright of Wetlands is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biodiversity is crucial for human well-being and sustenance, especially for rural communities that directly depend on plant resources. We investigated the plant selection process among rural communities in the Brazilian semiarid region. We aimed to understand how these communities choose plants for various functions, including fuel, construction, and forage. We hypothesized that people's choices are influenced by specific functional plant traits, leading them to select the most suitable species for each purpose. Our results support this hypothesis, as they showed that agropastoralists base their plant choices on functional traits that correspond to their needs. For instance, wood density, which is directly linked to wood durability, plays a key role in selecting plants for fuel and construction. By integrating ethnobotany and functional ecology, this study highlights the connection between functional plant traits and Local Ecological Knowledge (LEK), and thus contributes to a deeper understanding of the nuanced bond between humans and biodiversity. This allowed us to identify functional plant traits that guide plant selection in the Caatinga and probably also in other semiarid tropical regions worldwide. Based on our results, we conclude that functional plant traits play a critical role in decision-making for the selection of plant species for different primary uses. [ABSTRACT FROM AUTHOR]

Key message: Analysis of wood anatomical traits revealed that drought tolerance predominates in early-successional communities, and vessel variability is relevant for species' ecological success in seasonally dry tropical environments. Successional tropical dry forests harbor a diverse array of species subjected to a strong seasonal precipitation regime. Considering that wood encompasses diverse functional properties related to stem hydraulics and mechanical support, in this study, we asked which quantitative anatomical traits are exhibited by co-occurring species in early (EC)- and late (LC)-successional communities. We used generalized linear mixed-effects models to estimate and compare means and standard deviations of wood traits (vessel area, vessel density, vessel grouping, and fiber dimensions) between eight EC and between 13 LC co-occurring species. Wood traits were highly heterogeneous. High vessel redundancy, a property associated with water safety involved in the prevention of hydraulic failure, prevails among species coexisting in EC but is maintained through succession by the same species in LC. Highly variable fiber dimensions indicate that species coexisting in LC possess different characteristics associated with mechanical resistance. Low wood density species typical of LC, which are absent from EC, displayed wood anatomical features associated with drought-evasion mechanisms. This result implies that deforestation not only reduces taxonomic but also functional diversity. Future research should adopt a standard deviation analysis approach, as this will allow confirming the high variability in vessel diameter, even in diffuse porous species, as a key feature for the ecological success of plants facing succession-driven changes in seasonally dry environments. [ABSTRACT FROM AUTHOR]

Background: Safeguarding refers to the protection of health and wellbeing and enabling "life free from harm, abuse and neglect" (Safeguarding People 2019). In Ireland, the Health Service Executive (HSE) drafted a revised 2019 policy to replace the original policy on safeguarding adults at risk of abuse. A Safeguarding Committee was founded in Beaumont Hospital, Dublin to prepare for policy implementation and staff training. Aims: To establish staff awareness and understanding of safeguarding to guide training and policy implementation. Method: Cross-sectional study of 223 hospital staff using a 10-question paper survey. Results: Suboptimal awareness of the revised HSE policy, reporting structures and confidence levels amongst staff. In-person and online training identified as the most popular methods of learning. Conclusions: Knowledge and confidence gaps can be addressed in future training. Identifying education gaps will help guide training and policy implementation. [ABSTRACT FROM AUTHOR]

Wood water content, wood dry mass fraction, wood deposits and mineral inclusions separately affect wood mechanical properties, as well as plant survival and growth rates. Tree species occurring in recovering vegetation from deforestation face water stress, which is a particularly strong environmental filter in tropical dry forest regions. In this study, we analyze wood density and its associated variables of tree species present in early and late successional communities. We assessed and compared their wood density, wood water content, wood dry mass fraction, as well as wood cellular deposits, secretory elements and mineral inclusions which were described through anatomical sections. Wood density ranged from 0.10 g/cm3 (Jacaratia mexicana in late successional community) to 0.92 g/cm3 (Lysiloma divaricatum in early successional community). Successional species showed low intraspecific variability, despite large differences in the environmental conditions in the communities where they grow. Species with high wood water content were restricted to late successional communities, and pioneers showed higher wood density than non-pioneer species, which supports the linkage between high wood density and harsh environmental filtering through hydraulic safety. Wood density did not differ between columnar cacti (Pachycereus pecten-aboriginum and Pilosocereus collinsii) and tree species such as Bursera simaruba. Starch, tannins and crystals were abundant in most successional species and some species had gums; these deposits could potentially influence wood density and hydraulic, defense and storage plant functions. Our results suggest that modifications in the life cycle of successional tropical dry forest tree species due to anthropogenic activities may not be an important source of wood density variation. [ABSTRACT FROM AUTHOR]

Despite the ecological importance of wetland forests, their classification is still unsatisfactory, partly due to insufficient knowledge about the environmental drivers of their spatial heterogeneity. We examined the spatial variation of six community attributes in a tropical wetland forest and analyzed the underlying causes by using linear distance measures and geomorphological zonation as proxies of environmental heterogeneity. The study was conducted in a wetland forest located on a coastal plain of southern Mexico. Vegetation was sampled in two distinct landforms: coastal lagoon and river channel. For each plot we determined two other proxies of environmental variation, namely distance to the sea, and distance to closest water body. We assessed the effects of these environmental factors on wetland forest attributes through linear modelling. Except for species richness, all other attributes were heterogeneous across space, with aboveground biomass showing the largest variation. Overall, forest structural attributes in plots located along the highly dynamic main river channel were higher than those recorded around a relatively stable coastal lagoon, suggesting better conditions for wetland forest development in the former area. Models consistently included geomorphological zone, as well as distance proxies in most of them, with variable effects on community attributes. The spatial variation of this wetland forest was associated with different combinations of environmental proxies, with geomorphology being a key driver of this variability. A thorough understanding of the factors driving the spatial variation of wetland forests will lead to a more sensible ecological classification. [ABSTRACT FROM AUTHOR]

Context: Landscape structure can affect seed dispersal, but the spatial scale at which such effect is maximized (scale of effect, SoE) is unknown. Objectives: We assessed patterns and predictors of SoE on the seed rain in two Mexican regions: the relatively well-preserved Lacandona rainforest, and the more deforested Los Tuxtlas rainforest. We hypothesized that source limitation at Los Tuxtlas makes seed dispersal more reliant on landscape patterns measured across larger spatial scales, especially when considering connectedness-related landscape metrics and dispersal-dependent responses. Methods: We recorded the abundance and diversity of tree seeds in 20 forest sites per region, separately assessing local (dropping from neighboring trees) and dispersed (immigrant) seeds. We measured forest cover, fragmentation, and matrix openness in 11 concentric landscapes surrounding each site and tested for differences in SoE among regions, landscape metrics, response variables, and seed origins. Results: Contrary to expectations, SoE did not differ between regions and seed origins. Yet, as expected, forest cover tended to have larger SoE than matrix openness, with fragmentation showing intermediate values. Response variables also followed the predicted SoE pattern (abundance < diversity < species richness). Conclusions: Forest cover has larger SoE than matrix openness, possibly because forest cover is related to large-scale processes (e.g. long-distance dispersal) and matrix openness may drive small-scale processes (e.g. edge effects). Species richness may have larger SoE because of its dependence on long-distance dispersal. Therefore, to accurately assess the effect of landscape structure on seed dispersal, the optimal scale of analysis depends on predictor and response variables. [ABSTRACT FROM AUTHOR]

Myocardial Bridging (MB) refers to the band of myocardium that abnormally overlies a segment of a coronary artery. This paper quantitatively evaluates the influence of MB of the left anterior descending artery (LAD) on myocardial perfusion of the entire left ventricle. We studied 131 consecutive patients who underwent hybrid rest/stress 13N-ammonia positron emission tomography (PET) and coronary computed tomography angiography (CCTA) due to suspected myocardial ischemia. Patients with previous myocardial infarction and/or significant coronary artery disease (≥ 50% stenosis) were excluded. Myocardial perfusion measurements were compared between patients with and without LAD-MB. Additionally, we evaluated the relationship between anatomical characteristics (length and depth) of LAD-MB and myocardial perfusion measurements. 17 (13%) patients presented a single LAD-MB. Global myocardial perfusion reserve (MPR) was lower in patients with LAD-MB than in patients without LAD-MB (1.9 ± 0.5 vs. 2.3 ± 0.6, p < 0.01). Global stress myocardial blood flow (MBF) was similar in patients with and without LAD-MB (2.2 ± 0.4 vs. 2.3 ± 0.7 ml/g/min, p = 0.40). Global rest MBF was higher in patients with LAD-MB than in patients without LAD-MB (1.2 ± 0.3 vs. 1.0 ± 0.2 ml/g/min, p < 0.01). Global rest MBF, stress MBF, and MPR quantifications were similar in patients with superficial and deep LAD-MB (all p = NS). We did not find any correlation between length and global rest MBF, stress MBF nor MPR (r = - 0.14, p = 0.59; r = 0.44, p = 0.07; and r = 0.45, p = 0.07 respectively). Quantitative myocardial perfusion suggests that LAD-MB may be related to impaired perfusion reserve, an indicator of microvascular dysfunction. Anatomical characteristics of LAD-MB were not related to changes in myocardial perfusion. [ABSTRACT FROM AUTHOR]

The relief of amplification inhibition in preserved phytoplankton samples is a major challenge in genetic studies relying on single-cell sequencing. The successful amplification of rDNA genes varies considerably depending on the organisms, fixatives, and time of analysis after collection. Among other fixatives, RNAlater® is found to be a suitable choice for PCR amplification after long-term storage. In this study, we tested the performance of RNAlater® samples applied to single-cell PCR amplification in isolates of the thecate dinoflagellate genus Tripos, with an amplification success over 70%. The single-cell protocol proposed in this study amplified an average of 650 pb of large subunit and small subunit rDNA fragments in RNAlater® preserved cells after 5 months. Furthermore, it was possible to obtain rDNA sequences from samples up to 8 months old. The approach described here could also be useful to amplify a wide range of thecate and non-thecate dinoflagellate taxa, especially those species difficult to maintain in culture. [ABSTRACT FROM AUTHOR]

The magnitude of the carbon sink in second-growth forests is expected to vary with successional biomass dynamics resulting from tree growth, recruitment, and mortality, and with the effects of climate on these dynamics. We compare aboveground biomass dynamics of dry and wet Neotropical forests, based on monitoring data gathered over 3-16 years in forests covering the first 25 years of succession. We estimated standing biomass, annual biomass change, and contributions of tree growth, recruitment, and mortality. We also evaluated tree species' contributions to biomass dynamics. Absolute rates of biomass change were lower in dry forests, 2.3 and 1.9 Mg ha y, after 5-15 and 15-25 years after abandonment, respectively, than in wet forests, with 4.7 and 6.1 Mg ha y, in the same age classes. Biomass change was largely driven by tree growth, accounting for at least 48% of biomass change across forest types and age classes. Mortality also contributed strongly to biomass change in wet forests of 5-15 years, whereas its contribution became important later in succession in dry forests. Biomass dynamics tended to be dominated by fewer species in early-successional dry than wet forests, but dominance was strong in both forest types. Overall, our results indicate that biomass dynamics during succession are faster in Neotropical wet than dry forests, with high tree mortality earlier in succession in the wet forests. Long-term monitoring of second-growth tropical forest plots is crucial for improving estimates of annual biomass change, and for enhancing understanding of the underlying mechanisms and demographic drivers. [ABSTRACT FROM AUTHOR]

Coniferous plantations have been widely used by reforestation programs seeking to mitigate the effects of deforestation in mountainous areas in different parts of the world. However, some studies show that pine plantations can simulate natural mechanisms of succession, thereby facilitating the incorporation of other native species of mid- and late-successional stages. Existing pine plantations could function as a substitute habitat and facilitate the establishment of native and endangered cloud forest species. To test this hypothesis, we planted two endangered species from the family Juglandaceae ( Juglans pyriformis and Oreomunnea mexicana) under twelve-year-old canopy plantations of Pinus patula and compared them to individuals planted in open (control) sites and recorded their survival and growth. The results show that the survival of J. pyriformis and O. mexicana was significantly higher below the canopy of P. patula plantations than in the open site. However, growth rates varied significantly among species and sites. Although pine plantations may favor the survival of seedlings, they cannot ensure the growth of plants without additional forest management. [ABSTRACT FROM AUTHOR]

Globally, climate is a fundamental driver of plant species' geographical distributions, yet we still lack a good understanding of climatic variation on tropical mountains and its consequences for elevational floristic patterns. In a seasonally dry region of southern Mexico, we analysed meteorological patterns along a large elevational gradient (0-3670 m a.s.l.) and examined their relationship with changes in floristic richness. Meteorological patterns were characterised using two data sources. First, climatic information was extracted from cartography and records from a few existing meteorological stations. Additionally, air temperature and humidity were recorded hourly during 1 year with data loggers, at sites representing 200-m elevation increments. Floristic information was extracted from a database containing 10,124 records of plant collections, and organized in 200-m elevational belts. Climatic charts distinguished three climate types along the gradient, all with marked rainfall seasonality, but these bore little correspondence with the information obtained with the data loggers. Mean annual air temperature decreased with increasing elevation (lapse rate of 0.542 °C 100 m). Thermal oscillation was minimum around 1400 m and increased towards both extremes of the gradient. Relative humidity opposed this pattern, with maxima between 800 and 1800 m, decreasing towards the highest elevations. An analysis of temperature frequency distributions revealed meteorological features undetectable from the annual or monthly means of this variable; despite an overall gradual transition of the proportions of time recorded at different temperatures, some changes did not conform to this pattern. The first discontinuity occurred between 1000-1200 m, where dominant temperatures shifted abruptly; also noticeable was an abrupt increase of the proportion of time elapsed at 0.1-10 °C between 2400 and 2600 m. Air temperature appears to be the most influential climatic factor driving elevational variation of plant species richness in this region. [ABSTRACT FROM AUTHOR]

Metabolic syndrome represents a growing burden in the Mexican population with an increasing presence as evidenced by the most recent epidemiological data, showing a prevalence of 49.8 % in 2006. The cardiovascular hazard of metabolic syndrome has been proven in numerous occasions; these patients present an increased risk of cardiovascular disease not only because of epicardial coronary occlusion but also from microvascular disease secondary to endothelial dysfunction. Myocardial perfusion imaging using both single-photon emission computed tomography and positron emission tomography can be effectively used for the evaluation of established coronary artery disease as well as in the assessment of high-risk asymptomatic patients. In this review, we briefly discuss the role of myocardial perfusion imaging studies and its current and potential applications for patients with metabolic syndrome. [ABSTRACT FROM AUTHOR]

Background/aim: Cardiovascular disease is the leading cause of mortality in patients with chronic kidney disease and has a strong association with hyperphosphatemia. Dialysis is the major treatment tool for attaining serum phosphorus control. Phosphorus removal can be increased with hemodiafiltration. We compared the effect of hemodiafiltration and hemodialysis on serum phosphorus and phosphorus removal and changes in cardiovascular variables in a short-term follow-up. Methods: Adult patients with end-stage renal disease were randomized to receive hemodialysis or hemodiafiltration for 3 months. Clinical and biochemical variables were recorded monthly. Cardiac resonance was done at randomization and at the end of follow-up. Results: A total of 24 patients were studied (10 in hemodialysis and 14 in hemodiafiltration) with a mean age of 34.7 ± 11.4 years. The two groups did not differ as for age and blood pressure control at baseline. Phosphorus removal was higher (1,099 ± 239 in hemodiafiltration vs. 864 ± 366 mmol/session in hemodialysis, p < 0.05) and serum phosphorus was lower in the hemodiafiltration group at the end of follow-up (3.4 ± 0.8 in hemodiafiltration vs. 4.5 ± 1.6 mg/dl in hemodialysis, p < 0.05). We found a significant increase in ejection fraction only in the hemodiafiltration group. There was a trend to smaller increase in myocardial mass and a decrease in left ventricular end-diastolic volume only in the hemodiafiltration group. The changes in cardiac variables were significantly associated with changes in serum phosphorus levels. Conclusion: Hemodiafiltration was associated with better control of serum phosphorus and improvement in left ventricular ejection fraction, compared with hemodialysis. [ABSTRACT FROM AUTHOR]

Unplanned urban development threatens natural ecosystems. Assessing ecosystem recovery after anthropogenic disturbances and identifying plant species that may facilitate vegetation regeneration are critical for the conservation of biodiversity and ecosystem services in urban areas. At the periphery of Mexico City, illegal human settlements produced different levels of disturbance on natural plant communities developed on a lava field near the Ajusco mountain range. We assessed natural regeneration of plant communities 20 years after the abandonment of the settlements, in sites that received low (manual harvesting of non-timber forest products), medium (removal of aboveground vegetation), and high (removal of substrate and whole vegetation) disturbance levels. We also tested the potential facilitative role played by dominant tree and shrub species. Plant diversity and vegetation biomass decreased as disturbance level increased. Sites with high disturbance level showed poor regeneration and the lowest species similarity compared to the least disturbed sites. Six dominant species (i.e., those with the highest abundance, frequency, and/or basal area) were common to all sites. Among them, three species (the tree Buddleja cordata, and two shrubs, Ageratina glabrata and Sedum oxypetalum) were identified as potential facilitators of community regeneration, because plant density and species richness were significantly higher under their canopies than at open sites. We propose that analyzing community structural traits of the successional vegetation (such as species diversity and biomass) and identifying potential facilitator species are useful steps in assessing the recovery ability of plant communities to anthropogenic disturbances, and in designing restoration strategies. [ABSTRACT FROM AUTHOR]

Since its discovery in 1972 (ref. 1), the cranium KNM-ER 1470 has been at the centre of the debate over the number of species of early Homo present in the early Pleistocene epoch of eastern Africa. KNM-ER 1470 stands out among other specimens attributed to early Homo because of its larger size, and its flat and subnasally orthognathic face with anteriorly placed maxillary zygomatic roots. This singular morphology and the incomplete preservation of the fossil have led to different views as to whether KNM-ER 1470 can be accommodated within a single species of early Homo that is highly variable because of sexual, geographical and temporal factors, or whether it provides evidence of species diversity marked by differences in cranial size and facial or masticatory adaptation. Here we report on three newly discovered fossils, aged between 1.78 and 1.95 million years (Myr) old, that clarify the anatomy and taxonomic status of KNM-ER 1470. KNM-ER 62000, a well-preserved face of a late juvenile hominin, closely resembles KNM-ER 1470 but is notably smaller. It preserves previously unknown morphology, including moderately sized, mesiodistally long postcanine teeth. The nearly complete mandible KNM-ER 60000 and mandibular fragment KNM-ER 62003 have a dental arcade that is short anteroposteriorly and flat across the front, with small incisors; these features are consistent with the arcade morphology of KNM-ER 1470 and KNM-ER 62000. The new fossils confirm the presence of two contemporary species of early Homo, in addition to Homo erectus, in the early Pleistocene of eastern Africa. [ABSTRACT FROM AUTHOR]

We examined general and family-specific patterns of vascular plant richness along a large elevational gradient (0-3,670 m a.s.l.), assessed the continuity of these patterns and analysed their potential underlying causes in a high diversity region of the Sierra Madre del Sur, Oaxaca, Mexico. We used a vascular plant database constructed previously. The gradient was divided into 18 200-m elevation belts. To examine elevational patterns of richness, we used both observed and estimated (interpolated) species richness, as well as genus and family observed richness, for each belt. A generalised linear model (GLM) was used to assess the effect of altitude on area-corrected species richness (standard area = 100 km), and a numerical classification of the elevational belts based on species richness was performed. Overall, richness at the three taxonomic levels decreased with elevation, but some individual families departed from this pattern. A sharp drop in species richness was observed at 1,800 m, and the dendrogram separated two elevational floristic groups at this elevation. The GLM revealed a significant negative effect of elevation on species richness. Despite this overall decreasing pattern for vascular plants along this extensive gradient, an examination of some family-specific patterns revealed the existence of other elevation-diversity relationships, indicating taxon-specific responses to elevation. The most noticeable discontinuity in species richness, at ca. 1,800 m, is likely related to a critical temperature isocline. [ABSTRACT FROM AUTHOR]

Analyzing the relationship between the spatial structures of environmental variables and of the associated seedling and sapling communities is crucial to understanding the regeneration processes in forest communities. The degree of spatial structuring (i.e., spatial autocorrelation) of environmental and sapling community variables in the cloud forest of Teipan, S Mexico, were analyzed at a 1-ha scale using geostatistical analysis; after fitting semivariogram models for each set of variables, the association between the two sets was examined through cross-variograms. Kriging maps of the sapling community variables (density, cover, species richness, and mortality and recruitment rates) were obtained through conditional simulation method. Canopy openness, total solar radiation, litter depth, soil temperature and soil moisture were spatially structured, as were sapling density, species richness and sapling mortality rate. Mean range in semivariograms for environmental and sapling community variables were 13.14 ± 3.67 and 12.68 ± 5.71 m (±SE), respectively. The spatial structure of litter depth was negatively associated with the spatial structures of sapling density, species richness, and sapling community cover; in turn, the spatial structure of soil moisture was positively associated with the spatial structure of recruitment rate. These associations of the spatial structures of abiotic and sapling community variables suggest that the regeneration processes in this cloud forest is driven by the existence of different microsites, largely characterized by litter depth variations, across which saplings of tree species encounter a range of opportunities for successful establishment and survival. [ABSTRACT FROM AUTHOR]

Coronary CT angiography (CCTA) and cardiovascular magnetic resonance (CMR) have evolved as quite useful techniques in chronic/acute coronary artery disease evaluation. The calcium score measurement quantifies coronary artery calcium and classifies the patients into low, intermediate, and high risk of major adverse coronary events. The CCTA value resides in the high accuracy to exclude the presence of coronary artery disease. CMR allows the acquisition of images throughout the body in any tomographic plane without limitations imposed by body habitus; also, it allows to characterize cardiovascular anatomy and structure, tissue composition, right and left ventricular function, and visualize and quantify myocardial perfusion along with viability. Since the acquisition is performed with cardiac gating in both methods, the left and right ventricular function can be calculated along with valvular characterization. Both techniques provide high-value anatomical/functional information that finally will impact on the patient's treatment and survival. [ABSTRACT FROM AUTHOR]

We updated the floristic checklist of the Nizanda region, Isthmus of Tehuantepec (southern Mexico), characterized the occurring plant communities based on dominant species, and described the region’s flora according to life form, growth form, growth type, and growth habit spectra. Ten years of botanical exploration, along with surveys in 188 100-m2 samples from different vegetation types, provided the baseline floristic information. Ordination and classification analyses were performed to examine the degree of differentiation between communities. Geographical ranges of all species were used to assess biogeographical relationships of this flora. The inventory includes 920 species (553 genera, 124 families). More than one-third of the families were represented by a single species, whereas the 10 richest families had 43% of the species richness. Dendrograms showing plot classification at three taxonomic levels (species, genus and family) revealed savannah as the most strongly differentiated community amid seven vegetation types. Regarding growth forms, forbs and trees prevailed. Phanerophytes were the most common life form category, whereas herbs and woody plants were the dominant growth types. The largest richness for all taxonomic levels was recorded in the tropical dry forest. The expanded floristic knowledge gained for the Nizanda region provided better criteria to revise the classification scheme of its vegetation. Our preliminary biogeographical analysis illustrates the role of the Isthmus of Tehuantepec as a corridor for thermophilous floras between two oceanic watersheds, and as a natural distributional limit for several Mesoamerican plant species. [ABSTRACT FROM AUTHOR]

Topography strongly affects the distribution of insolation in the terrain. Patterns of incoming solar radiation affect energy and water balances within a landscape, resulting in changes in vegetation attributes. Unlike other regions, in seasonally dry tropical forest areas the potential contribution of topography-related environmental heterogeneity to β-diversity is unclear. In Mt. Cerro Verde (Oaxaca), S. Mexico, we: (1) modelled potential energy income for N- and S-facing slopes based on a digital elevation model, (2) examined the response of vegetation structure to slope aspect and altitude and (3) related variations in plant diversity to topographyrelated heterogeneity. Vegetation survey and modelling of potential energy income (SOLEI-32 model) were based on 30 plots equally distributed among three altitudinal belts defined for each slope of the mountain; combining the three altitudinal belts and the two slopes produced six environmental groups, represented by five vegetation plots each. Potential energy income was about 20% larger on the S than on the N slope (9,735 versus 8,138 MJ/m2), but it did not vary with altitude. In addition, the temporal behaviour of potential energy income throughout the year differed greatly between slopes. Vegetation structure did not show significant changes linked to the environmental gradients analysed, but altitude and aspect did affect β-diversity. We argue that the classic model of slope aspect effect on vegetation needs reconsideration for tropical landscapes. [ABSTRACT FROM AUTHOR]

Purpose: To demonstrate the presence of endothelial dysfunction (ED) in asymptomatic patients with type 2 diabetes mellitus (DM) by using (13)N-ammonia-positron emission tomography (PET). PET can identify ED by quantifying myocardial blood flow (MBF) during rest, cold pressor test (CPT), and pharmacologic stress. The endothelial-dependent vasodilation index (EDVI), myocardial flow reserve (MFR), and the percentage of the change between rest and CPT (%DeltaMBF) are markers of endothelial function.Procedures: Thirty-nine subjects were studied (19 women and 20 men); 22 recently diagnosed type 2 diabetic patients and 17 healthy controls (HC). A three-phase (13)N-ammonia-PET was performed.Results: Mean EDVI was 1.208 +/- 0.34 vs. 1.55 +/- 0.37 (diabetic vs. HC group, respectively) (p = 0.002), MFR was 2.803 +/- 1.39 vs. 3.27 +/- 0.72 (p = NS), and the %DeltaMBF was 20 +/- 34% vs. 55 +/- 37% (p = 0.002). Rest MBF and CPT MBF were normalized to the rate pressure product (RPP). EDVI' and %DeltaMBF' were calculated using the corrected values for the RPP. Mean EDVI' was (0.864 +/- 0.250 vs. 1.110 +/- 0.238, p = 0.004) and mean %DeltaMBF' was (-8.2 +/- 14.7% vs. 4.5 +/- 12.1%, p = 0.005).Conclusions: Asymptomatic, recently diagnosed type 2 diabetes patients present ED that can be quantified by (13)N-ammonia-PET. [ABSTRACT FROM AUTHOR]

Abstract Rustic coffee plantations are characterised by the use of numerous wild and cultivated tree species for providing shade to the coffee shrubs. This paper analyses the role of these plantations in wild tree conservation through the examination of their patterns of floristic variation in southern Mexico. The studied plantations included a total of 45 plant species, most of which were wild tree species, including both mature forest and pioneer taxa. An extrapolation of the species accumulation curve among stands indicated that the whole system, composed of more than 100 coffee plantations, may harbour as many as 34 species of wild trees. The floristic structure of rustic coffee plantations was highly variable. This variation is a result of a combination of factors such as human management, original stand cover and the asynchrony in development stage of different plantations. This promotes a large ß-diversity in the system. Thus, although a single plantation may have a limited potential to preserve wild tree species, it is the whole ensemble of floristically heterogeneous plantations which renders this agroforestry system valuable for plant diversity conservation, particularly in a region where native forest vegetation has almost disappeared. [ABSTRACT FROM AUTHOR]

The heterogeneity of xerophytic vegetation developing on limestone outcrops immersed in a tropical deciduous forest matrix was studied in Nizanda (S México). The study units comprised three clearly distinct communities based on their physiognomy and substrate, representing a gradient of edaphic aridity: (1) xerophytic scrub (XS); (2) tropical deciduous forest on rock (TDFr); and (3) tropical deciduous forest on deeper soil (TDFs). Structural and floristic variables were gathered in nine 100 m2 plots by community. In the 0.27 ha sampled 211 plant species were recorded. Total floristic richness by community decreased with increasing edaphic aridity: 159 species in TDFs, 107 in TDFr, and 36 in XS. Although significant differences were observed between the three communities for only four structural variables (total and upper stratum species densities, and relative monocotyledon density and cover), other variables confirmed the differences between the two forest communities and the XS (total and upper stratum cover, density, and basal area). TDFr and XS also differed from TDFs with respect to lower stratum species density, and absolute monocotyledon density and cover. The results showed the importance of monocotyledons and the prevalence of clonality in TDFr and XS. A comparison between limestone outcrop and inselberg vegetation indicated a virtual absence of therophytes, graminoid herbs, cryptogamic crusts, and desiccation-tolerant and carnivorous plants in the former, whereas the prevalence of monocotyledon mats, and xerophytic and succulent plants is the most striking similarity between these rocky environments. Xerophytic vegetation of limestone outcrops in Nizanda may be seen as analogous of relictual communities that existed during a northbound migration of Neotropical flora, towards the arid zones of North America. [ABSTRACT FROM AUTHOR]

This study was conducted in the Chiapas Highlands, a tropical mountain region where traditional agricultural practices have resulted in a mosaic landscape of forest fragments embedded in a matrix of secondary vegetation and crop fields. The question addressed was how may woody species richness be affected by forest fragment attributes derived from traditional laud-use patterus. Species inventories of total woody species, canopy and understorey trees, and shrubs were obtained in 22 forest fragments (⩾ 5 ha). Multiple regression analyses were applied to examine the effects of size, matrix, isolation and shape of the forest fragments on richness of these species guilds. Fragment size was cor- related with shape (r = 0.75) and isolation (r = -0.69), and isolation was correlated with shape (r = -0.75). Total species richness, and number of shrubs and understorey trees in fragments were related to isolation; moreover, additive effects of fragment shape were found for shrubs. The number of canopy species was not related to any fragment variable. Matrix did not help to explain species richness, possibly due to the landscape structure created by the traditional land-use patterns. In addition to size and isolation, we point out the need of considering shape and matrix as additional fragmentation attributes, along with social and economic factors, if we are ever going to be successful in our management and conservation actions. [ABSTRACT FROM AUTHOR]

Studies the sequence of enamel growth to distinguish modern humans from Homo erectus and earlier hominins. Incremental markings in enamel; Key determinant of tooth formation time; Insights into the history of adult morphologies.

Reports on hominin fossils discovered west of Lake Turkana, Kenya in 2001, which differ markedly from other, contemporary hominin fossils. Belief that early hominin phylogeny is best represented by Australopithecus afarensis; Description of the new fossil, which is assigned a genus of hominin and points to an early diet-driven adaptive radiation.

The diet of extant elephants ( Loxodonta in Africa, Elephas in Asia) is dominated by C3 browse although some elephants have a significant C4 grass component in their diet. This is particularly noteworthy because high-crowned elephantid cheek teeth represent adaptation to an abrasive grazing diet and because isotopic analysis demonstrates that C4 vegetation was the dominant diet for Elephas in Asia from 5 to 1 Ma and for both Loxodonta and Elephas in Africa between 5–1 Ma. Other proboscideans in Africa and southern Asia, except deinotheres, also had a C4-dominated diet from about 7 Ma (when the C4 biomass radiated in tropical and subtropical regions) until their subsequent extinction. [ABSTRACT FROM AUTHOR]

Describes a species of Australopithecus based on nine hominid dental, cranial and postcranial specimens from Kanapoi and 12 specimens from Allia Bay, Kenya. Description of Australopithecus anamensis; Geological context and dating; Paleoecology and fauna.

Reports on the discovery of Australopithecus anamensis fossils from strata lying between tephra dated 4.17 and 4.12 million years ago. Details of the find which occurred in Kenya; Importance of this find in terms of dating the origin of man.

Copyright of Tschermaks Mineralogische und Petrographische Mitteilungen (1889-1927) is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)