Intra-annual density fluctuations in tree rings are proxies of air temperature across Europe.

Intra-Annual Density Fluctuations (IADFs) are an important wood functional trait that determine trees' ability to adapt to climatic changes. Here, we use a large tree-ring database of 11 species from 89 sites across eight European countries, covering a climatic gradient from the Mediterranean to northern Europe, to analyze how climate variations drive IADF formation. We found that IADF occurrence increases nonlinearly with ring width in both gymnosperms and angiosperms and decreases with altitude and age. Recently recorded higher mean annual temperatures facilitate the formation of IADFs in almost all the studied species. Precipitation plays a significant role in inducing IADFs in species that exhibit drought tolerance capability, and a growth pattern known as bimodal growth. Our findings suggest that species with bimodal growth patterns growing in western and southern Europe will form IADFs more frequently, as an adaptation to increasing temperatures and droughts.

Silver nanoparticles enter the tree stem faster through leaves than through roots.

A major environmental pollution problem is the release into the atmosphere of particulate matter, including nanoparticles (NPs), which causes serious hazards to human and ecosystem health, particularly in urban areas. However, knowledge about the uptake, translocation and accumulation of NPs in plant tissues is almost completely lacking. The uptake of silver nanoparticles (Ag-NPs) and their transport and accumulation in the leaves, stems and roots of three different tree species, downy oak (Quercus pubescens Willd.), Scots pine (Pinus sylvestris L.) and black poplar (Populus nigra L.), were assessed. In the experiment, Ag-NPs were supplied separately to the leaves (via spraying, the foliar treatment) and roots (via watering, the root treatment) of the three species. Uptake, transport and accumulation of Ag were investigated through spectroscopy. The concentration of Ag in the stem was higher in the foliar than in the root treatment, and in poplar more than in oak and pine. Foliar treatment with Ag-NPs reduced aboveground biomass and stem length in poplars, but not in oaks or pines. Species-specific signals of oxidative stress were observed; foliar treatment of oak caused the accumulation of H2O2 in leaves, and both foliar and root treatments of poplar led to increased O2- in leaves. Ag-NPs affected leaf and root bacteria and fungi; in the case of leaves, foliar treatment reduced bacterial populations in oak and poplar and fungi populations in pine, and in the case of roots, root treatment reduced bacteria and increased fungi in poplar. Species-specific mechanisms of interaction, transport, allocation and storage of NPs in trees were found. We demonstrated definitively that NPs enter into the tree stem through leaves faster than through roots in all of the investigated tree species.

Oak tree-rings record spatial-temporal pollution trends from different sources in Terni (Central Italy).

Monitoring atmospheric pollution in industrial areas near urban center is essential to infer past levels of contamination and to evaluate the impact for environmental health and safety. The main aim of this study was to understand if the chemical composition of tree-ring wood can be used for monitoring spatial-temporal variability of pollutants in Terni, Central Italy, one of the most polluted towns in Italy. Tree cores were taken from 32 downy oaks (Quercus pubescens) located at different distances from several pollutant sources, including a large steel factory. Trace element (Cr, Co, Cu, Pb, Hg, Mo, Ni, Tl, W, U, V, and Zn) index in tree-ring wood was determined using high-resolution laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We hypothesized that the presence of contaminants detected in tree-rings reflected industrial activities over time. The accumulation of contaminants in tree-rings was affected by anthropogenic activities in the period 1958-2009, though signals varied in intensity with the distance of trees from the industrial plant. A stronger limitation of tree growth was observed in the proximity of the industrial plant in comparison with other pollutant sources. Levels of Cr, Ni, Mo, V, U and W increased in tree-ring profiles of trees close to the steel factory, especially during the 80's and 90's, in correspondence to a peak of pollution in this period, as recorded by air quality monitoring stations. Uranium contents in our tree-rings were difficult to explain, while the higher contents of Cu, Hg, Pb, and Tl could be related to the contaminants released from an incinerator located close to the industrial plant. The accumulation of contaminants in tree-rings reflected the historical variation of environmental pollution in the considered urban context.

Wood anatomical responses of oak saplings exposed to air warming and soil drought.

Water is vital for plant performance and survival. Its scarcity, induced by a seasonal decline in soil water availability or an increase of evaporative demand, can cause failures of the water conducting system. An adequate tolerance to drought and the ability to acclimate to changing hydraulic conditions are important features for the survival of long-lived woody plants in dry environments. In this study we examine secondary growth and xylem anatomical acclimation of 6 year old saplings of three European oak species (Quercus robur, Q. petraea, Q. pubescens) during the third consecutive year of exposure to soil drought and/or air warming (from 2007 to 2009). Intra-annual pinning was applied to mark the development of the formation of the annual ring 2009. Vessel size, parenchyma cell density and fiber size produced at different time of the growing season 2009 were compared between drought and warming treatments and species. Drought reduced secondary growth and induced changes in xylem structure while air warming had little effect on wood anatomical traits. Results indicate that drought-exposed saplings adjust their xylem structure to improve resistance and repairing abilities after cavitation. All species show a significant radial growth reduction, a reduced vessel size with diminished conductivity and a slightly increased density of parenchyma cells. Comparisons between species fostered our understanding of the relationship between the inter-specific xylem hydraulic plasticity and the ecological response to drought. The stronger changes observed for Q. robur and Q. petraea indicate a lower drought tolerance than Q. pubescens.

Responses of leaf nitrogen and mobile carbohydrates in different Quercus species/provenances to moderate climate changes.

Global warming and shortage of water have been evidenced in the recent past and are predicted for the future. Climate change will inevitably have considerable impact on plant physiology, growth, productivity and forest ecosystem functions. The present study determined the effects of simulated daytime air warming (+1 to 1.5 °C during the growing season), drought (-40% and -57% of mean precipitation of 728 mm during the 2007 and 2008 growing season, respectively) and their combination, on leaf nitrogen (N) and non-structural carbohydrates (NSC) of two Quercus species (Q. robur and Q. petraea) and provenances (two provenances for each species) grown in two soil types in Switzerland across two treatment years, to test the hypothesis that leaf N and NSC in the more water-sensitive species (Q. robur) and provenances (originating from water-rich locations) will more strongly respond to global warming and water deficit, compared to those in the more drought-tolerant species (Q. petraea) or provenances. No species- and provenance-specific responses in leaf N and NSC to the climate treatment were found, indicating that the results failed to support our hypothesis. The between-species variation of leaf N and NSC concentrations mainly reflected differences in biology of the two species, and the between-provenance variation of N and NSC concentrations apparently mirrored the climate of their origins. Hence, we conclude that (i) the two Quercus species studied are somewhat insensitive, due to their distribution covering a wide geographical and climate range, to moderate climate change within Switzerland, and (ii) a moderate global warming of B1 scenario (IPCC 2007) will not, or at least less, negatively affect the N and carbon physiology in Q. robur and Q. petraea.

Xylem hydraulic adjustment and growth response of Quercus canariensis Willd. to climatic variability.

Global change challenges forest adaptability at the distributional limit of species. We studied ring-porous Quercus canariensis Willd. xylem traits to analyze how they adjust to spatio-temporal variability in climate. Trees were sampled along altitudinal transects, and annual time series of radial growth (ring width (RW)) and several earlywood vessel (EV) traits were built to analyze their relationships with climate. The trees responded to increasing water constraints with decreasing altitude and changes in climate in the short term but the analyses showed that xylem did not acclimate in response to long-term temperature increase during the past 30 years. The plants' adjustment to climate variability was expressed in a different but complementary manner by the different xylem traits. At low elevations, trees exhibited higher correlations with water stress indices and trees acclimated to more xeric conditions at low elevations by reducing radial growth and hydraulic diameter (D(H)) but increasing the density of vessels (DV). Average potential conductivity (K(H)) was similar for trees at different altitudes. However, inter-tree differences in xylem traits were higher than those between altitudes, suggesting a strong influence of individual genetic features or micro-site conditions. Trees exhibited higher RW those years with larger D(H) and particularly the linear density of vessels (DV(l)), but partly, climatic signals expressed in RW differed from those in EVs. Trees produced larger D(H) after cold winters and wet years. Ring width responded positively to wet and cool weather in fall and spring, whereas the response to climate of DV and K(H) was generally opposite to that of RW. These relationships likely expressed the negative impact of high respiration rates in winter on the carbon pools used to produce the EVs in the next spring and the overall positive influence of water availability for trees. Our results showed that trees at different sites were able to adjust their hydraulic architecture to climatic variability and temperature increase during recent decades coordinating several complementary traits. Nonetheless, it should be monitored whether they will succeed to acclimate to future climatic scenarios of increasing water stress.

Can any ostrich fly?: some new data on belief bias in syllogistic reasoning.

According to one version of the mental models theory (Oakhill, J.V., Johnson-Laird, P.N., Garnham, A., 1989. Believability and syllogistic reasoning. Cognition 31, 117-140) beliefs exert their influence on reasoning in three ways. First they can affect the interpretation of the premises, for example by conversion. Second, they can curtail the search for alternative models of the premises, if an initial model supports a believable conclusion. Third, they can act as a filter on any conclusion that is eventually generated. This last influence is important in explaining the effects of belief bias in one-model syllogisms with no convertible premises, since such syllogisms, by definition, have no alternative models. However, the most natural interpretation of such a filter is that it filters out conclusions and leads to the response 'no valid conclusion'. The present study, which was conducted with groups of both British and Italian subjects, looked at the effect of prior knowledge on syllogistic reasoning, and showed that: (1) invalid conclusions for such one model syllogisms, either thematic or abstract, are typically not of the type 'no valid conclusion', but state invalid relations between the end terms; (2) belief-bias is completely suppressed when previous knowledge is incompatible with the premises, and therefore the premises themselves are always considered. The results are compatible with a version of the mental models theory in which a representation of prior knowledge precedes modelling of the premises, which are then incorporated into the representation of this knowledge. The relation between this theory and other accounts of belief bias in syllogistic reasoning, and the implications of these findings for reasoning more generally, are considered.

The influence of affective factors on time perception.

Several studies have suggested that both affective valence and arousal affect the perception of time. However, in previous experiments, the two affective dimensions have not been systematically controlled. In this study, standardized photographic slides rated for emotional valence and arousal were projected to two groups of subjects for 2, 4, and 6 sec. One group of subjects estimated the projection duration on an analog scale, whereas the second group of subjects reproduced the intervals by pushing a button. Heart rate and skin conductance responses were also recorded during stimulus presentation as indices of attention and arousal. Time estimation results showed neither a main effect of valence nor a main effect of arousal. A highly significant valence x arousal interaction affected duration judgments. For low-arousal stimuli, the duration of negative slides was judged relatively shorter than the duration of positive slides. Fog high-arousal stimuli, the duration of negative slides was judged longer than the duration of positive slides. The same interaction pattern was observed across judgment modalities. These results are interpreted in terms of a model of action tendency, in which the level of arousal controls two different motivational mechanisms, one emotional and the other attentional.

Salivary electrolytes in treated hypertensives at low or normal sodium diet.

The aim of this study was to investigate possible abnormalities in salivary electrolytes in hypertensives treated with ace-inhibitors (ACE-I) or calcium antagonists (Ca-ANT) at low or normal sodium intake. Hypertensives treated with ACE-I (n.14) or Ca-ANT (n.22) and 13 normotensives were studied during normal or restricted Na intake. Na, K, Ca, Mg and Cl were determined in saliva samples collected by using a standardized adsorption procedure (SALIVETTE). Na intake was evaluated by determination of the 24-hr urinary Na excretion. Similar concentrations of Na, K, Ca, and Cl were found in normotensives and in hypertensives treated with ACEI or Ca-ANT both at low or normal Na diet. Magnesium in saliva appeared reduced in ACEI-treated hypertensives (0.28 +/- 0.06 mmol/l) in comparison to the similar values of normotensives (0.53 +/- 0.05) and Ca-ANT treated hypertensives (0.54 +/- 0.07). In normotensives and in treated hypertensives lowering of Na intake did not change the salivary content of Ca, Mg and Cl but produced in saliva a reduction of Na associated to a rise in K. Salivary Na/K ratio was significantly correlated with 24 hr urinary Na excretion in normotensives (r = 0.77; p < 0.05) and in hypertensives treated with ACE-I (r = 0.74; p < 0.05) or Ca-ANT (r = 0.62; p < 0.05). The low salivary magnesium in ACE-I-HT may have a role in the occasional ACEI-dependent dysgeusia. Salivary Na/K ratio may be used as a rough index of Na intake in treated hypertensives.

Aminotransferases and lactate dehydrogenase in saliva of diabetic patients.

Although inflammatory or degenerative changes in salivary glands have been demonstrated in genetic animal models of diabetes mellitus and in experimental diabetes, no information is available in diabetics on the possible leakage in saliva of cytosolic enzymes as markers of salivary cell injury. Aspartate (GOT) and alanine (GPT) aminotransferases and lactate dehydrogenase (LDH) were determined in saliva samples collected by the Salivette method from well-controlled insulin-dependent (IDDM n = 11) and non-insulin-dependent (NIDDM n = 18) diabetic patients and from age-cross-matched healthy subjects (n = 33). In IDDM salivary concentrations of GOT (112.55 +/- 23.94 UI/L) and LDH (1120.27 +/- 168.31 UI/L) were similar to those found in the NIDDM (90.94 +/- 19.64, and 1255.43 +/- 221.40 UI/L respectively), but higher (p < 0.05) than those observed in normal subjects (33.09 +/- 3.71, and 423.58 +/- 39.94, UI/L respectively). GPT was higher in NIDDM than IDDM, which in turn was higher than in normal subjects (42.78 +/- 14.72, 16.45 +/- 3.74 and 6.85 +/- 1.52 UI/L respectively). Salivary and serum values of GOT, GPT and LDH were not correlated. Determination of cytosolic enzymes in saliva may be useful for monitoring the diabetic involvement of salivary glands.

[Comparison of methods for determining erythrocyte deformability]. / Confronto fra metodiche per la determinazione della deformabilità eritrocitaria.

We have studied the erythrocyte deformability by means of the filtration technique proposed by Reid et al. and with the new technique proposed by Schmid-Schönbein et al. using a Filtrometer MF4. We have studied 50 healthy subjects (24 females and 26 males) aged 25-61 (mean age 34 years). Our results show that slope 80% (SL80) and minimal value (MV) represent the more reliable indexes given by Filtrometer MF4. This instrument gives an exhaustive and automated analysis of erythrocyte deformability. Its results allow us a more extensive knowledge of hemorheological behavior of red blood cells in very low flow conditions.

Detection of circulating DNA in plasma of patients with pulmonary embolism by counterimmunoelectrophoresis.

In order to confirm the usefulness of free plasma DNA detection in the diagnosis of pulmonary embolism (PE), we have studied 16 patients with PE, 33 with various diseases, and 13 normal subjects. Free plasma DNA was detectable in 15 of 16 patients with PE (94%) and in 3 control patients, but never in plasma from normal subjects. In most cases, DNA was detectable until the 10th day after PE. In conclusion, counterimmunoelectrophoresis is a rapid, inexpensive and specific test which may be used as an exclusion test in the detection of patients suspected of having PE, who will have to undergo more extensive evaluation.

[Behavior of glutamic-pyruvic transaminase during the clinical course of acute myocardial infarct]. / Comportamento della transaminasi glutammico-piruvica lungo il decorso clinico dell'infarto acuto del miocardio.

The increase in serum Alanine-aminotransferase (SGPT) levels in 104 patients with acute myocardial infarction is studied. The time course of serum enzyme changes shows two peaks of activity: in the first days after infarction and at the end of the second week of the disease. The clinical significance of this finding is discussed.