Observational evidence on the effects of mega-fires on the frequency of hydrogeomorphic hazards. The case of the Peloponnese fires of 2007 in Greece

Even though rare, mega-fires raging during very dry and windy conditions, record catastrophic impacts on infrastructure, the environment and human life, as well as extremely high suppression and rehabilitation costs. Apart from the direct consequences, mega-fires induce long-term effects in the geomorphological and hydrological processes, influencing environmental factors that in turn can affect the occurrence of other natural hazards, such as floods and mass movement phenomena. This work focuses on the forest fire of 2007 in Peloponnese, Greece that to date corresponds to the largest fire in the country's record that burnt 1773 km2, causing 78 fatalities and very significant damages in property and infrastructure. Specifically, this work examines the occurrence of flood and mass movement phenomena, before and after this mega-fire and analyses different influencing factors to investigate the degree to which the 2007 fire and/or other parameters have affected their frequency. Observational evidence based on several data sources collected during the period 1989–2016 show that the 2007 fire has contributed to an increase of average flood and mass movement events frequency by approximately 3.3 and 5.6 times respectively. Fire affected areas record a substantial increase in the occurrence of both phenomena, presenting a noticeably stronger increase compared to neighbouring areas that have not been affected. Examination of the monthly occurrence of events showed an increase even in months of the year were rainfall intensity presented decreasing trends. Although no major land use changes has been identified and chlorophyll is shown to recover 2 years after the fire incident, differences on the type of vegetation as tall forest has been substituted with lower vegetation are considered significant drivers for the observed increase in flood and mass movement frequency in the fire affected areas. © 2017 Elsevier B.V

Below-Ground Hydraulic Conductance Is a Function of Environmental Conditions and Tree Size in Scots Pine

1. Variations in water tension in a transpiring tree cause elastic changes in stem diameter. To better understand the dynamics of these variations, stem diameter changes and sap flow rates were monitored simultaneously in trees from two Scots pine chronosequences in Scotland. 2. Tree below-ground hydraulic conductance (kbg) was estimated from the relationship between leaf-specific sap flow rates and the difference between stem and soil water potentials estimated from diameter variations in the stem. 3. In a given tree, kbg varied both within and among days, with conductance increasing as a function of sap flow and evaporative demand. These patterns could be explained in terms of a composite model of root water transport and possible changes in the gating of aquaporins. 4. We interpreted these trends of increasing kbg with evaporative demand as a mechanism to enhance the ability of trees to control leaf water potential and keep it within physiologically acceptable limits, with potential implications for our general understanding of plant water relations, and for the estimation and modelling of ecosystem water fluxes. 5. Across trees, kbg declined with increasing tree age/size, but the proportional contribution of below-ground to whole-tree hydraulic resistance also declined. This is consistent with an increase in below-ground carbon allocation in old/tall trees and a partial acclimation of tall trees to hydraulic limitations. It is argued that these trends have to be considered when discussing the importance of tree height for water transport and growth

A GIS-based integrated approach predicts accurately post-fire Aleppo pine regeneration at regional scale

Context: This study investigates post-fire natural regeneration of Aleppo pine (Pinus halepensis) forests at Ilia region (Peloponnesus, Greece) following the catastrophic fire of 2007. Aims: The objective of this study is the prediction of P. halepensis post-fire regeneration at a regional scale through an integrated geographic information systems (GIS) model as a basis for post-fire management plans. Methods: The model was developed in three interconnected stages: (1) field data collection, (2) development of two prediction models (based on interpolation of field data and multicriteria evaluation (MCE) that combined factors known to affect regeneration), and (3) combination of applied models using Bayesian statistics. Results: Post-fire pine regeneration presented high variation among the studied plots. Redundancy analysis revealed the positive effect of fallen branches and a negative correlation with altitude. Both modeling approaches (geostatistical and MCE) predicted the post-fire pine regeneration with high accuracy. A very significant correlation (r00.834, p<0.01) was found between the combined final model and the actual number of counted seedlings, illustrating that less than 10 % of the studied area corresponds to sites of very low post-fire pine regeneration. Conclusion:s The combination of GIS models increased the prediction success of different levels of pine regeneration. Lowaltitude areas with low grass cover overlying tertiary deposits were proved the most suitable for pine regeneration, while stands developing on limestone proved least suitable. The proposed methodology providesmanagement authoritieswith a sound tool to quickly assess Aleppo pine post-fire regeneration potential. © INRA /Springer-Verlag France 2012

Interleukin-6 in preterm premature rupture of membranes as an indicator of neonatal outcome

Background. The aim of this study was to investigate whether the levels of interleukin-6 (IL-6) can be used as markers of adverse outcome in preterm neonates born after preterm premature rupture of membranes (PPROM). Methods. This study involved 109 preterm neonates and their mothers. The PPROM group consisted of 58 neonates who were born after PPROM, and the control group consisted of 51 neonates. IL-6 levels were measured in umbilical cord blood, maternal blood sampled during delivery and in neonatal blood taken on the fourth day of life. Results. In the PPROM group, IL-6 concentrations in maternal blood, cord blood, and neonatal blood were significantly higher in neonates with sepsis, compared with those without sepsis (P < 0.001). Choosing 108.5 pg/ml as a cut-off concentration of IL-6 in umbilical cord blood for neonatal sepsis resulted in sensitivity 95%, specificity 100%, positive predictive value 100%, and negative predictive value 97.4%. Concerning IL-6 in maternal blood, a cut-off concentration of 81 pg/ml showed sensitivity 90%, specificity 97.4%, positive predictive value 94.7%, and negative predictive value 94.9%. Eighteen of 20 neonates with early sepsis and seven of nine neonates, who died in the PPROM group, were born of mothers with IL-6 levels above the cut-off concentration in their blood during delivery. Conclusions. IL-6 in umbilical cord blood was the most significant variable for predicting early onset sepsis in preterm neonates. IL-6 in maternal blood was indicative of intrauterine environmental threats and might be used to identify pregnancies where intervention would be appropriate

Feeding difficulties in a neonate with primary cricopharyngeal achalasia treated by cricopharyngeal myotomy

Primary cricopharyngeal achalasia resulting from failure of relaxation of the cricopharyngeus muscle is a rare but significant cause of dysphagia in newborns. Symptoms may be nonspecific. Although surgical management with cricopharyngeal myotomy has been employed successfully for the treatment of this disorder, swallowing difficulties may persist postoperatively, probably due to association with other esophageal abnormalities. Alternative methods of feeding may be required to ensure adequate nutrient intake. We report the case of a full-term, 2-day-old neonate with this rare clinical condition, treated by myotomy, in whom swallowing difficulties persisted for several weeks after surgery. Satisfactory nutrition was maintained postoperatively with the support of a nasogastric feeding tube until improvement in feeding intolerance. Complete symptomatic relief was attained at the age of 5 months. © 2003 Elsevier Ireland Ltd. All rights reserved

Significance of hypocarbia in the development of periventricular leukomalacia in preterm infants

Background: Despite rapid advances in the management of preterm infants, periventricular leukomalacia (PVL) remains a considerable problem in neonatal intensive care. The aim of this study was to determine whether hypocarbia is associated with the development of PVL in mechanically ventilated, preterm infants and to emphasize the importance of avoiding this disturbance. Methods: The authors evaluated 52 mechanically ventilated infants with a gestational age of <34 weeks, who exhibited hypocarbia in the first three postnatal days (lowest carbon dioxide tension being <25 mmHg). These infants were then compared with 52 infants in a control group not exhibiting hypocarbia, matched for birthweight and gestational age. A diagnosis of PVL was made on the basis of the results of cranial ultrasonography. Confounding factors potentially associated with the development of PVL were controlled in logistic regression analyses. Results: Of the 52 mechanically ventilated preterm infants with hypocarbia, 10 (19.2%) developed cystic PVL, and six (11.5%) developed periventricular echodensity. Of the 52 infants in the control group only two (3.8%) developed cystic PVL, and one (1.9%) infant developed periventricular echodensity. The authors observed no significant differences in other prenatal and perinatal risk factors between the two groups. Conclusion: Hypocarbia in mechanically ventilated preterm infants during the first days of life is suggested as being an independent predictor of PVL, predisposing these infants to subsequent neurodevelopmental delay

Levels of bone collagen markers in preterm infants: Relation to antenatal glucocorticoid treatment

Although the beneficial effects of antenatally administered glucocorticoids are well documented, data on the potential of adverse consequences are limited. The objective of this study was to determine the effects of antenatally administered glucocorticoids on biochemical markers of bone metabolism of 55 preterm infants with a gestational age of 24-34 weeks who were enrolled in the study. Neonates were divided into two groups according to antenatal exposure to corticosteroids. There were no significant differences between the groups in clinical characteristics and anthropometric variables. We studied blood levels of osteocalcin (OC), carboxy-terminal propeptide of type I procollagen (PICP), and carboxy-terminal telopeptide of type I collagen (ICTP) at the time of delivery, on postnatal day 10, and at 2 and 4 months of life. Comparing the groups, we found statistically significant reduction in PICP levels at birth in corticosteroid-exposed neonates (P < 0.05). The levels of bone markers increased progressively on the first days of life. There were no significant differences between groups in bone markers at 10 days or at 2 and 4 months of life. We found no significant difference for bone markers between groups of infants exposed to single or repeated maternal corticosteroid treatments. In summary, antenatal glucocorticoid treatments are suggested to have a negative impact on fetal bone formation as reflected by low PICP levels at birth. However, this negative effect on bone markers seems to be a temporary effect that subsides on the first days of life and afterward. © 2007 Springer-Verlag