Maternal prenatal stress influences offspring neurodevelopment and birth outcomes including the ratio of males to females born; however, there is limited understanding of what types of stress matter, and for whom. Using a data-driven approach with 27 variables from questionnaires, ambulatory diaries, and physical assessments collected early in the singleton pregnancies of 187 women, 3 latent profiles of maternal prenatal stress emerged that were differentially associated with sex at birth, birth outcomes, and fetal neurodevelopment. Most women (66.8%) were in the healthy group (HG); 17.1% were in the psychologically stressed group (PSYG), evidencing clinically meaningful elevations in perceived stress, depression, and anxiety; and 16% were in the physically stressed group (PHSG) with relatively higher ambulatory blood pressure and increased caloric intake. The population normative male:female secondary sex ratio (105:100) was lower in the PSYG (2:3) and PHSG (4:9), and higher in the HG (23:18), consistent with research showing diminished male births in maternal stress contexts. PHSG versus HG infants were born 1.5 wk earlier (P < 0.05) with 22% compared to 5% born preterm. PHSG versus HG fetuses had decreased fetal heart rate–movement coupling (P < 0.05), which may indicate slower central nervous system development, and PSYG versus PHSG fetuses had more birth complications, consistent with previous findings among offspring of women with psychiatric illness. Social support most strongly differentiated the HG, PSYG, and PHSG groups, and higher social support was associated with increased odds of male versus female births. Stress phenotypes in pregnant women are associated with male vulnerability and poor fetal outcomes.

Large fires account for a disproportionally high percentage of area burned with potentially severe environmental and socioeconomic impacts. This study characterizes extremely large fires (ELFs; 2500–24,843 ha) in Portugal (1998–2013) and the concomitant fuel and weather conditions, analyzing the response of ELF size to their variation. ELF burned less shrubland‐grassland (33% of the total ELF area) than forest (59% of total), the latter primarily composed by pine and pine‐eucalypt. High fuel hazard was the norm, as indicated by median values of 0.98 for fuel load as a fraction of potential (maximum) load and time since fire >14 years over 91% of the burned area. ELF occurred under anticyclonic circulation patterns, especially ridging, and 78% of them coincided with extreme fire danger days (corresponding to infrequent conditions) in conjunction with unstable atmosphere. Containment time, fire growth rate, and energy release metrics varied by 1 more order of magnitude than ELF size, hence indicating that size alone is insufficient to describe extreme fires. Distinct combinations between ambient weather conditions, atmospheric instability, and drought defined three categories of ELF as defined by size. Quantile regression indicated that increasingly larger fires showed gradually stronger responses to fire weather severity, highlighting the difficulty in restraining fire spread in flammable landscapes in the absence of extensive fuel treatments. Data limitations inherent to the methods used are discussed, and improvements to further advance the understanding of extreme fires are suggested.

Fire severity varies with forest composition and structure, reflecting micrometeorology and the fuel complex, but their respective influences are difficult to untangle from observation alone. We quantify the differences in fire weather between different forest types and the resulting differences in modeled fire behavior. Collection of in-stand weather data proceeded during two summer periods in three adjacent stands in northern Portugal, respectively Pinus pinaster (PP), Betula alba (BA), and Chamaecyparis lawsoniana (CL). Air temperature, relative humidity and wind speed varied respectively as CL < PP < BA, PP < CL < BA, and CL < BA < PP. Differences between PP and the other types were greatest during the warmest and driest hours of the day in a sequence of 10 days with high fire danger. Estimates of daytime moisture content of fine dead fuels and fire behavior characteristics for this period, respectively, from Behave and BehavePlus, indicate a CL < BA < PP gradient in fire potential. High stand density in CL and BA ensured lower wind speed and higher fuel moisture content than in PP, limiting the likelihood of an extreme fire environment. However, regression tree analysis revealed that the fire behavior distinction between the three forest types was primarily a function of the surface fuel complex, and more so during extreme fire weather conditions. OPEN ACCESSForests 2014, 5 2491

Near-instantaneous estimation of the moisture content of live fuels is complicated because of the large control exerted by physiological mechanisms. The commonly accepted reference method for measuring fuel moisture content is oven drying, which is time consuming. This study evaluates the use of a moisture analyzer (ML-50, A&D Company, Limited, Tokyo, Japan) for measuring the foliar moisture content of two common European species. The moisture of live leaves of Arbutus unedo L. (strawberry tree) and Quercus robur L. (pedunculate oak) was measured within a period of 15 min using two drying temperatures and compared with the oven-dried value. Correction factors were determined for estimating the oven-dried moisture content based on the measurement by the moisture analyzer. The power delivered during the drying process plays an important role in the moisture measured by the analyzer in relation to the oven-dried value. Increasing the drying time beyond the minimum period necessary for obtaining a reliable prediction of the oven-dried moisture does not significantly change the moisture measured at lower temperatures. The moisture analyzer is able to estimate the live foliage moisture content with high accuracy.Résumé : L'estimation quasi instantanée de la teneur en humidité des combustibles vivants est compliquée à cause du grand contrôle exercé par les mécanismes physiologiques. La méthode de référence généralement acceptée pour mesurer la teneur en humidité des combustibles est le séchage au four qui demande du temps. Cet article évalue un analyseur d'humidité (ML-50, A&D Company Ltd) pour mesurer la teneur en humidité des feuilles de deux espèces européennes communes. La teneur en humidité des feuilles vivantes d'Arbustus unedo L. (arbousier) et de Quercus robur L. (chêne pédonculé) a été mesurée pendant une période de 15 min en utilisant deux températures de séchage et comparée à la valeur obtenue par séchage au four. Des facteurs de correction ont été déterminés pour estimer la teneur en humidité par séchage au four à partir des mesures obtenues avec l'analyseur. La puissance fournie durant le processus de séchage a un effet important sur la teneur en humidité mesurée par l'analyseur en relation avec la valeur obtenue par séchage au four. Le fait d'augmenter le temps de séchage au-delà de la période minimale requise pour obtenir une prédiction fiable de la teneur en humidité selon la méthode de séchage au four ne change pas de façon significative la teneur en humidité mesurée à des températures plus faibles. L'analyseur d'humidité est capable d'estimer la teneur en humidité du feuillage vivant avec une grande précision. [Traduit par la Rédaction] Mots-clés : teneur en humidité des combustibles, combustibles légers vivants, équations de correction.

The capabilities of accurately estimating dead fuel moisture content and predicting the likelihood of selfsustained fire spread are crucial to plan prescribed fire operations and achieve the treatment goals, among other fire management objectives. After analysis to determine whether some existing models could be adopted or adapted, we developed user-friendly equations to predict the moisture content of dead fine fuels in blue gum (Eucalyptus globulus) litter and examined their prediction ability. Models with vapour pressure deficit, the FFMC code of the Canadian FWI System (or the no. of days since last precipitation in alternative) and noon 10-m open wind speed from the nearest weather station as independent variables fitted the data suitably, as well as a physics based model. The probability of sustained fire propagation in experimental burns carried out in reconstructed blue-gum litter in the laboratory was described through fuel moisture content, litter depth and fire-spread direction (backward or forward). Both types of equations will be further tested in blue gum stands.

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