Integrated global assessment of the natural forest carbon potential

Forests are a substantial terrestrial carbon sink, but anthropogenic changes in land use and climate have considerably reduced the scale of this system1. Remote-sensing estimates to quantify carbon losses from global forests2-5 are characterized by considerable uncertainty and we lack a comprehensive ground-sourced evaluation to benchmark these estimates. Here we combine several ground-sourced6 and satellite-derived approaches2,7,8 to evaluate the scale of the global forest carbon potential outside agricultural and urban lands. Despite regional variation, the predictions demonstrated remarkable consistency at a global scale, with only a 12% difference between the ground-sourced and satellite-derived estimates. At present, global forest carbon storage is markedly under the natural potential, with a total deficit of 226 Gt (model range = 151-363 Gt) in areas with low human footprint. Most (61%, 139 Gt C) of this potential is in areas with existing forests, in which ecosystem protection can allow forests to recover to maturity. The remaining 39% (87 Gt C) of potential lies in regions in which forests have been removed or fragmented. Although forests cannot be a substitute for emissions reductions, our results support the idea2,3,9 that the conservation, restoration and sustainable management of diverse forests offer valuable contributions to meeting global climate and biodiversity targets.

The global biogeography of tree leaf form and habit

Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling.

Native diversity buffers against severity of non-native tree invasions

Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4. Here, leveraging global tree databases5-7, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions.

Fast demographic traits promote high diversification rates of Amazonian trees

The Amazon rain forest sustains the world's highest tree diversity, but it remains unclear why some clades of trees are hyperdiverse, whereas others are not. Using dated phylogenies, estimates of current species richness and trait and demographic data from a large network of forest plots, we show that fast demographic traits – short turnover times – are associated with high diversification rates across 51 clades of canopy trees. This relationship is robust to assuming that diversification rates are either constant or decline over time, and occurs in a wide range of Neotropical tree lineages. This finding reveals the crucial role of intrinsic, ecological variation among clades for understanding the origin of the remarkable diversity of Amazonian trees and forests.

Beyond behavioural observations: a deeper view through the sensory reactions of children with profound intellectual and multiple disabilities

BACKGROUND

The present study was aimed at assessing the behavioural and physiological responsiveness of three children with profound intellectual and multiple disabilities to a set of sensory stimuli.

METHODS

Eighteen items, 'believed' by clinicians to be appropriate for routine interventions, were presented to the participants and responsiveness was assessed in terms of: (i) consistent behavioural and electrodermal reactions and (ii) biphasic changes in heart rate.

RESULTS

Results were twofold. First, all participants showed frequent consistent physiological reactions but rare consistent behavioural ones. Second, all participants showed biphasic changes in heart rate, pointing to the possibility of different appraisals (novelty and pleasantness) of most of the presented items.

CONCLUSIONS

Data here presented may have implications for the development and the emotional well-being of individuals with profound intellectual and multiple disabilities in that it suggests that reactions to, and potential appraisals of, sensory stimuli may occur despite the lack of consistent observable behaviours.

Drought-mortality relationships for tropical forests

*The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. *We assembled available data on tropical forest tree stem mortality before, during, and after recent drought events, from 119 monitoring plots in 10 countries concentrated in Amazonia and Borneo. *In most sites, larger trees are disproportionately at risk. At least within Amazonia, low wood density trees are also at greater risk of drought-associated mortality, independent of size. For comparable drought intensities, trees in Borneo are more vulnerable than trees in the Amazon. There is some evidence for lagged impacts of drought, with mortality rates remaining elevated 2 yr after the meteorological event is over. *These findings indicate that repeated droughts would shift the functional composition of tropical forests toward smaller, denser-wooded trees. At very high drought intensities, the linear relationship between tree mortality and moisture stress apparently breaks down, suggesting the existence of moisture stress thresholds beyond which some tropical forests would suffer catastrophic tree mortality.

Drought sensitivity of the Amazon rainforest

Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 10(15) to 1.6 x 10(15) grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.

Surface characterization and cell response of a PLA/CaP glass biodegradable composite material

Bioabsorbable materials are of great interest for bone regeneration applications, since they are able to degrade gradually as new tissue is formed. In this work, a fully biodegradable composite material containing polylactic acid (PLA) and calcium phosphate (CaP) soluble glass particles has been characterized in terms of surface properties and cell response. Cell cultures were performed in direct contact with the materials and also with their extracts, and were evaluated using the MTT assay, alkaline phosphatase activity, and osteocalcin measurements. The CaP glass and PLA were used as reference materials. No significant differences were observed in cell proliferation with the extracts containing the degradation by-products of the three materials studied. A relation between the materials wettability and the material-cell interactions at the initial stages of contact was observed. The most hydrophilic material (CaP glass) presented the highest cell adhesion values as well as an earlier differentiation, followed by the PLA/glass material. The incorporation of glass particles into the PLA matrix increased surface roughness. SEM images showed that the heterogeneity of the composite material induced morphological changes in the cells cytoskeleton.

Solitary hemangioma of the small bowel disclosed by wireless capsule endoscopy

A nine-year-old child presented with melena and anemia. She had similar symptoms five months earlier and had undergone an extensive workup with upper gastrointestinal endoscopy and colonoscopy, both normal and 99m-Tc-RBC-scintigraphy which was positive in the right lower quadrant. This time, capsule endoscopy was performed and disclosed an hemangioma with a dark spot suggesting recent bleeding in the ileum. The lesion was resected. Pathological examination revealed a transmural cavernous hemangioma. Small bowel hemangioma is a rare disease. Its diagnosis is extremely difficult and is usually obtained during surgery. Capsule endoscopy is an endoscopic technique that can improve preoperative diagnosis, as reported in the present case.

The influence of ramp rate on VO2peak and "excess" VO2 during arm crank ergometry

The principal aim of this study was to examine how different ramp rates influenced the attainment of peak physiological responses during incremental arm crank ergometry (ACE). Additionally, the study examined whether there was any evidence for the development of an "excess" VO (2) during ACE due to upward curvi-linearity in the VO (2)-work rate relationship, and whether this was influenced by the ramp rate. Sixteen physically active, though non-specifically trained, men (mean +/- S age 30 +/- 8 years; height 1.79 +/- 0.07 m; body mass 84.7 +/- 13.2 kg) volunteered to participate. Having completed a familiarisation test, all subjects returned to the laboratory to complete two ramp tests on an electrically-braked ergometer in a counter-balanced order. Both ramp tests started at 60 W with work rate subsequently incremented by either 6 or 12 W . min (-1). Pulmonary gas exchange was measured breath-by-breath throughout the tests. Subjects achieved a greater final work rate during the 12 W . min (-1) test compared to the 6 W . min (-1) test (168 +/- 28 vs. 149 +/- 26 W; p < 0.001). The VO (2peak) (3.06 +/- 0.65 vs. 2.96 +/- 0.48 L . min (-1); p = 0.27), HR (peak) (179 +/- 15 vs. 177 +/- 16 b . min (-1); p = 0.17) and V.E (peak) (112 +/- 22 vs. 105 +/- 16 L . min (-1); p = 0.09) were not different between the tests, but VCO (2peak) (3.54 +/- 0.64 vs. 3.27 +/- 0.46 L . min (-1); p = 0.01) RER (peak) (1.17 +/- 0.07 vs. 1.11 +/- 0.06; p < 0.001), and end-exercise blood (lactate) (11.9 +/- 2.1 vs. 10.8 +/- 2.6 mmol . L (-1); p = 0.005) were all higher in the 12 W . min (-1) test. An "excess" VO (2) was observed in 13 out of 16 tests at 12 W . min (-1) and in 15 out of 16 tests at 6 W . min (-1). Neither the magnitude of the "excess" VO (2) (0.42 +/- 0.41 vs. 0.37 +/- 0.18 L . min (-1); p = 0.66) nor the VO (2) at which the V.O (2)-work rate relationship departed from linearity (2.17 +/- 0.34 vs. 2.18 +/- 0.32 L . min (-1); p = 0.94) were significantly different between the two ramp tests. These data indicate that differences in ramp rate within the range of 6 - 12 W . min (-1) influence the peak values of work rate, VCO (2) and RER, but do not influence peak values of VO (2) or HR during ACE. The development of an "excess" VO (2) appears to be a common feature of ramp exercise in ACE, although the mechanistic basis for this effect is presently unclear.

[The use and interpretation of tuberculin tests]

The author reviews the difficulties in diagnosing tuberculosis infection with the current BCG National Vaccination Plan. The author points out some directions that, in her point of view, may provide a clearer interpretation of the tuberculin skin test, bearing in mind the child's clinical, epidemiologic and social background.

[Imaging of aortic aneurysms and dissections. Part 2. Aortic dissections]

The authors review the main imaging findings of aneurysms and dissections of the aorta. Based on the experience and imaging techniques available in their institution (Conventional Radiology, Sonography and Computed Tomography), they try to make a decision tree of radiologic procedures in ambulatory and emergency patients. Nowadays, in the majority of situations, these techniques allow the Radiologist to make the correct diagnosis, detect the complications and evaluate the patients in the pre and post-surgical phases. Other imaging techniques not available in their institution, such as Magnetic Resonance Imaging and Aortography, will be mentioned in view of their usefulness in some specific situations.

[Imaging of aneurysms and dissections of the aorta. Part 1--Aneurysms of the abdominal aorta]

The authors review the main imaging findings of aneurysms and dissections of the aorta. Based on the experience and imaging techniques available in their institution (Conventional Radiology, Sonography and Computed Tomography), they try to make a decision tree of radiologic procedures in ambulatory and emergency patients. Nowadays, in the majority of situations, these techniques allow the Radiologist to make the correct diagnosis, detect the complications and evaluate the patients in the pre and post-surgical phases. Other imaging techniques not available in their institution, such as Magnetic Resonance Imaging and Aortography, will be mentioned in view of their usefulness in some specific situations.

HM-PAO spect in head trauma

Single Photon Emission Computed Tomography (SPECT) after intravenous administration of Technetium-99m hexamethylpropylene-amine oxime (Tc-99m HM-PAO) makes possible the evaluation of cerebral perfusion. We have been assessing the diagnostic accuracy of SPECT in some groups of head trauma patients: the preliminary results of this study are presented. Fourteen patients have been selected, all of them showing some kind of focal neurological deficit; the Computed Tomography (CT) and Nuclear Magnetic Resonance (NMR) were normal, or showed lesions that could not be responsible for the neurological deficits. In all of the patients Tc-99m HM-PAO SPECT has been performed, showing changes in cerebral perfusion in areas correlated with the abnormalities elicited on clinical examination. These results show that Tc-99m HM-PAO SPECT is a better technique than CT or NMR in demonstrating the organic basis of some neurological deficits observed after head trauma.

Different patterns of inhibition of adrenaline-induced platelet aggregation and kinetics in vivo by acetylsalicylic acid and indobufen

The inhibitory effect of 50 mg/kg lysyl acetylsalicylic acid (ASA) intravenously injected 24 and 4 h before 80 micrograms/kg adrenaline, 40 mg/kg indobufen injected 15 min before, or a combination of ASA plus indobufen on the platelet aggregation and kinetics was evaluated in anaesthetized dogs previously injected with 111indium- (111In-) labelled platelets using gamma-camera dynamics studies. The highest degree of inhibition, indicated by the lowest platelet aggregation ratio decrease and the most significant 111In-labelled platelet mobilization from hepatic and splenic stores with a corresponding increase of labelled and unlabelled platelet counts in blood, was obtained in ASA-treated dogs. Such changes were less marked when ASA plus indobufen was injected. In indobufen-treated dogs a similar mobilization of 111In-labelled platelets with an increase in circulating platelet numbers was evident only after the second adrenaline injection. It is concluded that platelet mobilization is mainly dependent on the production of an ASA-sensitive substance.

Acute effects of adrenaline on platelet aggregation and kinetics in vivo

The platelet (Plt) contribution to cardiovascular events triggered by adrenergic stress is supported by some experimental and necropsy data, but a cause and effect link and mechanism have not yet been clearly demonstrated. Adrenergic stress was simulated by three successive adrenaline (A) injections (80 micrograms/kg) in anesthetized dogs previously infused with indium111 labelled Plt (111In-Plt) for a gamma-camera study. Adrenaline induced an acute and significant decrease in the Plt aggregation ratio (PAR) and a parallel decrease in the Plt count as well as in the circulating 111In-Plt, mirroring a significant and persistent Plt sequestration mainly in the liver and spleen. The long-lasting and significant decrease in the circulating Plt count observed 15 min after each A injection can be explained by a persistent retention of Plt. Further studies are in progress in order to disclose if this corresponds to platelet microaggregate embolization in microvessels of the organs so far analysed. If this postulate can be confirmed the hypothesis of an adrenergic stress triggering of ischemic events will be justified.

Glomerular hyperfiltration in insulin-dependent diabetes mellitus: no evidence for enhanced activity of the renin-angiotensin-aldosterone system

Glomerular hyperfiltration is a characteristic functional abnormality in insulin-dependent diabetes mellitus (IDDM) patients, but the underlying mechanisms remain controversial. Supine and ambulant plasma renin activity (PRA) and aldosterone were measured in ten IDDM patients with normal glomerular filtration rate (GFR), in ten IDDM patients with elevated GFR and in ten nondiabetic controls. Basal and stimulated PRA or aldosterone did not differ significantly between the three groups. These results suggest that in insulin-dependent diabetes the glomerular hyperfiltration is not causally related to hyperactivity of the renin-angiotensin-aldosterone system.

Epidemiological aspects of acute viral hepatitis in Portugal

Epidemiological aspects of 400 consecutive in-patients with acute viral hepatitis, aged one to 81 years, were studied: 180 patients were less than 15 years old (mean age 6.9 years) and 220 were older (mean age 33.8 years). Serum hepatitis markers were detected by RIA. Hepatitis A (HA) was diagnosed in 188 patients (47.0%), ages ranging from one to 34 years (mean age 8.5 years), hepatitis B (HB) in 163 patients (40.8%), ages ranging from two to 72 years (mean age 32.7 years) and non-A, non-B hepatitis (NANBH) in 41 patients (10.2%), ages ranging from two to 81 years (mean age 35.4 years). Two patients had simultaneous HA and HB, and in six patients the etiology was not classified. In patients less than 15 years old, HA was the commonest type (91.1%), other etiologies having a low frequency; in the age group over 15 years, HB represented the most frequent type (70.0%), followed by NANBH (16.8%) and HA (10.9%). The probable source of infection was unknown in most of the cases (51%). With regard to HA, secondary contact was frequently reported and small outbreaks were registered. Parenteral exposure was the main probable source of HB and NANBH virus infections, the transmission frequently being iatrogenic. Drug abuse was a rare source of infection.

Prevalence of viral hepatitis markers in the population of Portugal

The prevalence of viral hepatitis markers in apparently healthy individuals of both sexes, born and living in both urban and rural areas of all the Portuguese provinces, was studied by radioimmunoassay.The anti-HAV prevalence was determined in 1770 individuals, 1-84 years old, divided into 8 age groups. The HBsAg prevalence was determined in 1440 individuals, 15-84 years old, divided into 5 age groups, while the anti-HBs prevalence was determined in 1980 individuals, 1-84 years old, divided into 8 age groups. The data were standardized for the Portuguese population.The anti-HAV results were similar for both sexes and showed a general prevalence of 84.9%. No significant difference in the prevalences between urban and rural areas was found. Age-group prevalences of anti-HAV were: 1-4 years, 23.9%; 5-9 years, 61.3%; 10-14 years, 76.4%; 15-19 years, 93.4%; and over 30 years, 99%.The HBsAg results showed a general prevalence of 1.25% for persons over 15 years old (2.04% for males and 0.78% for females). The anti-HBs results were similar for both sexes and showed a general prevalence of 24.3%. The northern provinces tended to have a higher anti-HBs prevalence than the southern ones, except for Lisbon province which had the highest figure. Age-group prevalences of anti-HBs were: 1-4 years, 7.6%; 5-9 years, 12.6%; 10-14 years, 8.7%; 15-19 years, 23.5%; 20-29 years, 28.4%; and over 30 years, between 30.0% and 34.3%.Only 5.3% of the anti-HAV-positive individuals, 11.2% of the HBsAg carriers, and 9.2% of the anti-HBs-positive individuals had a history of acute hepatitis.These results show that Portugal may be considered an endemic area for viral hepatitis infections.