November April Research Articles

Salinity and spawning of nurseryfish, Kurtus gulliveri, in the Adelaide River of northern Australia with notes on electrofishing and photos of a male carrying eggs

Nurseryfish are unique among fishes in that the males carry the fertilized eggs on a supraoccipital hook on their head. In an attempt to learn where, when, and at what salinities spawning occurs, an ichthyoplankton net was towed at 14 stations in the Adelaide River from the mouth (38 ppt) to the most upstream sections of the river (0.1 ppt). Larval nurseryfish (5–27.5 mm SL) were collected, preserved and measured, and water chemistry parameters were recorded with each sample. Larvae were found in the mid-reaches of the river during July–October, most commonly at salinities between 13.6–0.5 ppt. Salinities increased as the dry season progressed. Larvae were not taken at salinities higher than 19 ppt, nor did they occur in the upper-most reaches of the river system during this time of the dry season. What nurseryfish do and where they occur during the massive influx of freshwater runoff during the wet season (November–April) remains a mystery. Electrofishing for nurseryfish proved to be ineffective in the Adelaide River due to its extraordinary turbidity which made recovery of stunned fish difficult and fresh material of males carrying eggs remains elusive. Two historic photographs showing males carrying eggs are described.

Large-scale drivers of Caucasus climate variability in meteorological records and Mt El'brus ice cores

Abstract. A 181.8 m ice core was recovered from a borehole drilled into bedrock on the western plateau of Mt El'brus (43°20′53.9′′ N, 42°25′36.0′′ E; 5115 m a.s.l.) in the Caucasus, Russia, in 2009 (Mikhalenko et al., 2015). Here, we report on the results of the water stable isotope composition from this ice core with additional data from the shallow cores. The distinct seasonal cycle of the isotopic composition allows dating by annual layer counting. Dating has been performed for the upper 126 m of the deep core combined with 20 m from the shallow cores. The whole record covers 100 years, from 2013 back to 1914. Due to the high accumulation rate (1380 mm w.e. year−1) and limited melting, we obtained isotopic composition and accumulation rate records with seasonal resolution. These values were compared with available meteorological data from 13 weather stations in the region and also with atmosphere circulation indices, back-trajectory calculations, and Global Network of Isotopes in Precipitation (GNIP) data in order to decipher the drivers of accumulation and ice core isotopic composition in the Caucasus region. In the warm season (May–October) the isotopic composition depends on local temperatures, but the correlation is not persistent over time, while in the cold season (November–April), atmospheric circulation is the predominant driver of the ice core's isotopic composition. The snow accumulation rate correlates well with the precipitation rate in the region all year round, which made it possible to reconstruct and expand the precipitation record at the Caucasus highlands from 1914 until 1966, when reliable meteorological observations of precipitation at high elevation began.

An Anomalous Genesis Potential Index for MJO Modulation of Tropical Cyclones

Abstract Modulation of tropical cyclone (TC) genesis by the Madden–Julian oscillation (MJO) has been quantitatively diagnosed by using a climatological genesis potential index (GPI). Analysis of TC genesis during November–April of 1979–2014 indicates the most effective factors controlling intraseasonal TC genesis are 850-hPa relative vorticity weighted by the Coriolis parameter fζr850 and 500-hPa vertical motion ω500. The total vertical wind shear and maximum potential intensity are unimportant, and the role of 600-hPa relative humidity is greatly represented by ω500. The MJO modulates TC genesis primarily through changing low-level vorticity induced by its Rossby wave gyres and meridional shears of equatorial zonal winds. A new intraseasonal GPI (ISGPI) is proposed to quantify the MJO’s modulation of TC genesis. The ISGPI significantly improves representation of intraseasonal variation of TC genesis in the tropics and in each subregion of the southern Indian Ocean, Australian monsoon, and South Pacific. In the hot spots of the Southern Hemisphere TC genesis zone, the probability of TC genesis can differ by a factor of 5–19 as a result of MJO modulation. The results suggest that the large-scale factors controlling TC genesis may vary with different time scales, and the climatological GPI may not be quite applicable for diagnoses of climate variability and future change of TC genesis potential. To simulate realistic impacts of the MJO on TC genesis, general circulation models must reproduce not only realistic eastward propagation but also the MJO low-level circulation structure. Application of the new ISGPI may have a large potential to improve dynamical subseasonal prediction of TC genesis.

Designing index-based livestock insurance for managing snow disaster risk in Eastern Inner Mongolia, China

Index-based agricultural insurance is of particular importance for vast, less heterogeneous and sparsely populated regions. This paper has designed an index-based livestock insurance for managing snow disaster risk for the pastoral regions of Eastern Inner Mongolia, China. Based on detailed information from field surveys, the designed insurance plan targets extra feeding costs induced by snow cover rather than mortality. It employs percentage height of grass covered by snow as the trigger for insurance payments and calculates the aggregate number of days triggered between November 1st and April 30th as the index for calculating insurance payments. A comparison with existing commercial mortality insurance (CMI) based on certainty-equivalent analysis indicates that the designed snow-index insurance (SII) is superior in terms of potential users’ welfare, as it is aimed correctly at the major source of income risk. Even when the loading for administrative costs is included in the premium, the SII still brings welfare improvements for most regions of the study area.

The Precipitation Variations in the Qinghai-Xizang (Tibetan) Plateau during 1961–2015

The variation of precipitation plays an important role in the eco-hydrological processes and water resources regimes on the Tibetan Plateau (TP). Based on the monthly mean precipitation data of 65 meteorological stations over the TP and surrounding areas from 1961 to 2015, variations, trends and temporal–spatial distribution of precipitation have been studied; furthermore, the possible reasons were also discussed preliminarily. The results show that the annual mean precipitation on the TP was 465.5 mm during 1961–2015. The precipitation in summer (June–August (JJA)) accounted for 60.1% of the whole year’s precipitation, the precipitation in summer half-year (May–October) accounted for 91.0%, while the precipitation in winter half-year (November–April) only accounted for 9.0% of the whole year’s precipitation. During 1961–2015, the annual precipitation trend was 3.8 mm/10a and the seasonal precipitation trends were 3.0 mm/10a, 0.0 mm/10a, −0.1 mm/10a and 0.4 mm/10a in spring, summer, autumn and winter on the TP, respectively. The precipitation has decreased from the southeastern to northwestern TP; the trend of precipitation has decreased with the increase of altitude, but the correlation was not significant. The rising of air temperature and land cover changes may cause the precipitation by changing the hydrological cycle and energy budget. Furthermore, different patterns of atmospheric circulation can also influence precipitation variation in different regions.

Oceanic Origins of Historical Southwest Asia Precipitation During the Boreal Cold Season

While a strong influence on cold season southwest Asia precipitation by Pacific sea surface temperatures (SSTs) has been previously established, the scarcity of southwest Asia precipitation observations prior to 1960 renders the region’s long-term precipitation history largely unknown. Here a large ensemble of atmospheric model simulations forced by observed time-varying boundary conditions for 1901–2012 is used to examine the long-term sensitivity of November–April southwest Asia precipitation to Pacific SSTs. It is first established that the models are able to reproduce the key features of regional variability during the best-observed 1960–2005 period and then the pre-1960 variability is investigated using the model simulations. During the 1960–2005 period, both the mean precipitation and the two leading modes of precipitation variability during November–April are reasonably simulated by the atmospheric models, which include the previously identified relationships with El Niño–Southern Oscillation (ENSO) and the multidecadal warming of Indo-Pacific SSTs. Over the full 1901–2012 period, there are notable variations in precipitation and in the strength of the SST influence. A long-term drying of the region is associated with the Indo-Pacific warming, with a nearly 10% reduction in westernmost southwest Asia precipitation during 1938–2012. The influence of ENSO on southwest Asia precipitation varied in strength throughout the period: strong prior to the 1950s, weak between 1950 and 1980, and strongest after the 1980s. These variations were not antisymmetric between ENSO phases. El Niño was persistently related with anomalously wet conditions throughout 1901–2012, whereas La Niña was not closely linked to precipitation anomalies prior to the 1970s but has been associated with exceptionally dry conditions thereafter.

Groundwater discharge and phosphorus dynamics in a flood-pulse system: Tonle Sap Lake, Cambodia

Tonle Sap Lake (Cambodia), a classic example of a “flood pulse” system, is the largest freshwater lake in SE Asia, and is reported to have one of the highest freshwater fish productions anywhere. During the dry season (November–April) the lake drains through a tributary to the Mekong River. The flow in the connecting tributary completely reverses during the wet monsoon (May–October), adding huge volumes of water back to the lake, increasing its area about six fold. The lake is likely phosphorus limited and we hypothesized that groundwater discharge, including recirculated lake water, may represent an important source of P and other nutrients. To address this question, we surveyed hundreds of kilometers of the lake for natural 222Rn (radon), temperature, conductivity, GPS coordinates and water depth. All major inorganic nutrients and phosphorus species were evaluated by systematic sampling throughout the lake. Results showed that there were radon hotspots, all at the boundaries between the permanent lake and the floodplain, indicating likely groundwater inputs. A radon mass balance model indicates that the groundwater flow to Tonle Sap Lake is approximately 10km3/yr, about 25% as large as the floodwaters entering from the Mekong River during the wet monsoon. Our results suggest that the groundwater-derived dissolved inorganic phosphorus (DIP) contribution to Tonle Sap is more than 30% of the average inflows from all natural sources. Since the productivity of the lake appears to be phosphorus limited, this finding suggests that the role of groundwater is significant for Tonle Sap Lake and perhaps for other flood pulse systems worldwide.

Multi-year climate variability in the Southwestern United States within a context of a dynamically downscaled twentieth century reanalysis

This investigation evaluates whether there is coherency in warm and cool season precipitation at the low-frequency scale that may be responsible for multi-year droughts in the US Southwest. This low-frequency climate variability at the decadal scale and longer is studied within the context of a twentieth-century reanalysis (20CR) and its dynamically-downscaled version (DD-20CR). A spectral domain matrix methods technique (Multiple-Taper-Method Singular Value Decomposition) is applied to these datasets to identify statistically significant spatiotemporal precipitation patterns for the cool (November–April) and warm (July–August) seasons. The low-frequency variability in the 20CR is evaluated by exploring global to continental-scale spatiotemporal variability in moisture flux convergence (MFC) to the occurrence of multiyear droughts and pluvials in Central America, as this region has a demonstrated anti-phase relationship in low-frequency climate variability with northern Mexico and the southwestern US By using the MFC in lieu of precipitation, this study reveals that the 20CR is able to resolve well the low-frequency, multiyear climate variability. In the context of the DD-20CR, multiyear droughts and pluvials in the southwestern US (in the early twentieth century) are significantly related to this low-frequency climate variability. The precipitation anomalies at these low-frequency timescales are in phase between the cool and warm seasons, consistent with the concept of dual-season drought as has been suggested in tree ring studies.

Winter mean lower tropospheric moisture over the Maritime Continent as a climate model diagnostic metric for the propagation of the Madden‐Julian oscillation

AbstractDespite its widespread influences on the atmosphere, the Madden‐Julian oscillation (MJO) remains poorly represented in state‐of‐the‐art general circulation models (GCMs). Motivated by recent findings that the horizontal advection of the mean low‐tropospheric moist static energy or moisture by the MJO winds plays a crucial role in the eastward propagation of the MJO, we investigate the relationship between lower tropospheric moisture patterns over the Indo‐Pacific and MJO eastward propagation in a suite of 23 GCM simulations. Model capability of reproducing the observed November–April mean lower tropospheric moisture pattern over the Indo‐Pacific, especially near the Maritime Continent (MC), is highly correlated with model skill in simulating MJO eastward propagation. In GCMs with difficulty capturing realistic MJO propagation, the amplitude of the mean low‐level moisture over the MC is greatly underestimated, leading to weak horizontal moisture gradients and thus discrepancies in moisture advection, significantly affecting MJO propagation. This study suggests that the mean lower tropospheric moisture pattern over the MC can serve as an important diagnostic metric for MJO propagation in climate models.

Effect of season and sunlight on viral kinetics during hepatitis C virus therapy

Background and aimsRapid viral response (RVR) during antiviral treatment for hepatitis C virus (HCV) predicts sustained viral response (SVR). Recently, vitamin D levels have been associated with SVR. As sunlight...

The Niger River Basin Moisture Sources: A Lagrangian Analysis

The Niger River basin (NRB) is located in the important climatic region of the African Sahel. In this study we use the Lagrangian tridimensional model FLEXPART v9.0 to identify and characterise the moisture sources for the NRB. This method allows the integration of the budget of evaporation minus precipitation over 10-day backward trajectories, thereby identifying the origins of the air masses residing over the NRB. The analysis was performed for the 35-year period from 1980 to 2014, which allowed us to identify the main semi-annual climatological moisture sources of the NRB, for November–April (NDJFMA) (dry season) and May–October (MJJASO) (wet season), and to quantify the respective moisture uptakes. Throughout the year, the NRB main moisture sources are located on the tropical eastern North Atlantic Ocean near Africa, the tropical eastern South Atlantic Ocean in the Gulf of Guinea, in the regions surrounding the Sahel and in the Mediterranean Sea. The extents of these sources vary between dry and wet seasons. In NDJFMA two regions appear in the east of the basin, which then join up, forming a larger source to the northeast of the basin in MJJASO, when three other less important moisture sources can be seen in central-equatorial Africa, the tropical western Indian Ocean and the Persian Gulf. In NDJFMA the majority of the moisture uptake comes from the NRB itself but then, later in MJJASO, when the precipitation increases over the basin the greatest uptake of moisture occurs over the tropical eastern South Atlantic Ocean, northeast Africa and the NRB, which suggests that these are the effective sources of precipitation in the basin in overall terms. The seasonal moisture uptake quantification over the moisture sources of the NRB, reveals that largest fraction of moisture income to the basin from outside its boundaries. Despite providing moisture to the NRB the source located in the tropical eastern North Atlantic Ocean does not contribute that much to precipitation in the basin. A daily (ten-day) backward analysis shows the importance of the moisture uptake within the NRB and from near moisture sources during the first few (backward) days, while the Atlantic Ocean sources and the Mediterranean became more important during the last five (backward) days of the analysis.

Heavy precipitation in the southwest of Iran: association with the Madden–Julian Oscillation and synoptic scale analysis

Some important characteristics of the November–April heavy precipitation in southwestern parts of Iran and their linkages to the Madden–Julian Oscillation (MJO) were assessed for the period of 1975–2011. Daily precipitation data in nine meteorological stations spread in various parts of the study area and the corresponding MJO indices were analyzed. For each station, precipitation data were sorted in descending order and those values that fell within 5% of the highest records were categorized as the heavy precipitation. Besides this, the 10% threshold was also analyzed as an axillary assessment. The considered heavy precipitation data (5% threshold) accounted from about 26–35% of total annual precipitation. About half of the heavy precipitation occurred during December–January period and the other half distributed within the months of March, February, November and April by about 17, 14, 13and 6%, respectively. The highest frequency of heavy precipitation was related to the MJO phase 8. After this, the more frequent precipitation events were respectively associated to the phases 2, 7, 1, 6, 5 and 4 of the MJO. For the phases 1, 2, 7 and 8 frequency of the heavy precipitation statistically increased when the MJO amplitude was greater than unity. In contrast, for phases 4 and 5, heavy precipitation was generally linked to the spells that the amplitude size was lower than unity. Formation of a strong north–south oriented cold front mainly in Saudi Arabia and west-east oriented warm fronts in the southwest of Iran were realized as the key elements for initiating heavy precipitation over the study area. Although development of the Mediterranean-based cyclonic circulation is essential for the formation of these fronts, moisture transport mostly originates from northern parts of the Arabian Sea, southern parts of the Red Sea and the Persian Gulf.

Reproductive and tissue plasticity in Arca noae (Bivalvia: Arcidae)

The reproductive strategy of an unexploited population of Arca noae from the salt-water Bizerte Lagoon (Tunisia, western Mediterranean), including its tissue plasticity, was studied. In total 309 individuals, collected monthly from October 2013 to September 2014, were examined; 142 were females, 42 were males and five were hermaphrodites. They were used in histological and immunohistochemical (stem marker: Pou5f1; proliferation marker: proliferating cell nuclear antigen (PCNA)) analyses of gonads and adjacent tissues (N = 189) as well as to compute the monthly condition index (N = 120). Water salinity, temperature and chlorophyll a concentration were recorded. Ripe ovaries were observed in two discrete periods, October–November and April–August. Both gonad ripenings were followed by spawning periods, November–April and July–September. The mature oocyte density showed that the first spawning period was less vigorous than the second one. These data also indicated that A. noae is a multiple spawner. Five cases of protandric hermaphroditism occurred from December to April. Gonad tissue was strictly associated and intermingled with the digestive gland and mantle muscle fibres. Seasonal variations were observed in the relative proportions of digestive gland and gonads: the former predominated when the latter regressed (March) and vice versa (peak in June). Seasonal transitions from germinal to somatic tissue and vice versa were hypothesised to occur through transdifferentiation mechanisms based on the activity of stem and proliferating cells. The condition index roughly increased along with gonad ripening and decreased during the spawning periods, although it did not run parallel to gonad evolution, because it also depended on chlorophyll a concentration, a proxy for phytoplankton density. The condition index was significantly correlated, by multiple regression, to both mature oocyte density and chlorophyll a concentration. Arca noae appears to have evolved a flexible reproductive strategy that makes it capable of exploiting diverse environmental conditions, which also involves tissue transdifferentiation.

Global participation in sport and leisure-time physical activities: A systematic review and meta-analysis

This review aimed to determine the most popular physical activities performed by children, adolescents, and adults globally. Statistic bureau websites and article databases Scopus, ProQuest, SPORTDiscus, and Science Direct were searched between November 17th, 2014 and April 31st, 2015. Eligible studies were published in the last 10 years with participation rates for specific physical activities among individuals five years or older. Data extraction for included articles (n = 64) was assessed independently and agreed upon by two authors. A random-effects model was used to calculate participation rates in specific activities for each age group and region. In total 73,304 articles were retrieved and 64 articles representing 47 countries were included in the final meta-analysis. Among adults, walking was the most popular activity in the Americas (18.9%; 95% CI 10.2 to 32.5), Eastern Mediterranean (15.0%; 95% CI 5.8 to 33.6), Southeast Asia (39.3%; 95% CI 0.9 to 98.0) and Western Pacific (41.8%; 95% CI 25.2 to 60.6). In Europe and Africa, soccer (10.0%; 95% CI 6.5 to 15.1) and running (9.3%; 95% CI 0.9 to 53.9), respectively, were top activities. Child and adolescent participation results were highly dependent upon region. American youth team sport participation was high, while youth from the Eastern Mediterranean and Western Pacific were more likely to report participation in lifelong physical activities. Global data for adults reflects a consistent pattern of participation in running and walking. Among all age groups and regions soccer was popular. In children and adolescents, preferences were variable between regions.

Influence of elevated CO2 and temperature on physiological traits and yield attributes of heat tolerant wheat genotype Halna grown inside open top chambers

Both CO2 and temperature caused significant changes in crop productivity. An experiment was conducted wherein wheat was grown inside open top chambers (OTCs) in order to determine the effects of elevated atmospheric carbon dioxide (CO2) and temperature on physiology and yield attributes of wheat genotype Halna. Halna was grown with two levels of carbon dioxide, i.e., ambient (400 ppm) and elevated (500 ± 20 ppm) and two levels of temperature, i.e., ambient, and ambient +2 °C during the Rabi (November–April) season of 2014–2015 at ICAR-RCER, Patna, India. The study revealed that elevated CO2 improved water use efficiency by 26.3%, photosynthetic rate by 14.6%, relative water content (RWC) by 15.9%, membrane stability index (MSI) by 6.6%, leaf area (LA) by 4.6%, plant height by 2.53% and grain yield by 26.9% as compared to ambient, while the activity of antioxidant enzymes were decreased, i.e., catalase by −12.59% and peroxidase by −21.04%. However, elevation of temperature by 2 °C decreased the photosynthetic rate by 15.9%, LA by 8.7% and grain yield by 11.7% but activity of CAT (+64.8%), and POX (+7.2%) were increased as compared to ambient condition. Simultaneous elevation of both (CO2 and temperature) caused non-significant increase in leaf area, number of grains ear−1, 1000 grain weight and grain yield as compared to ambient condition. The results indicated that elevated CO2 had positive effects, whereas elevated temperature had negative effects and with simultaneous elevation of CO2 and temperature, elevated CO2 nullified the negative effects of elevated temperature on photosynthetic characteristics and yield components of Halna.

Quantification of ice production in Laptev Sea polynyas and its sensitivity to thin-ice parameterizations in a regional climate model

Abstract. The quantification of sea-ice production in the Laptev Sea polynyas is important for the Arctic sea-ice budget and the heat loss to the atmosphere. We estimated the ice production for the winter season 2007/2008 (November–April) based on simulations with the regional climate model COSMO-CLM at a horizontal resolution of 5 km and compared it to remote sensing estimates. A reference and five sensitivity simulations were performed with different assumptions on grid-scale and subgrid-scale ice thickness considered within polynyas, using a tile approach for fractional sea ice. In addition, the impact of heat loss on the atmospheric boundary layer was investigated. About 29.1 km3 of total winter ice production was estimated for the reference simulation, which varies by up to +124 % depending on the thin-ice assumptions. For the most realistic assumptions based on remote sensing of ice thickness the ice production increases by +39 %. The use of the tile approach enlarges the area and enhances the magnitude of the heat loss from polynyas up to +110 % if subgrid-scale open water is assumed and by +20 % for realistic assumptions. This enhanced heat loss causes in turn higher ice production rates and stronger impact on the atmospheric boundary layer structure over the polynyas. The study shows that ice production is highly sensitive to the thin-ice parameterizations for fractional sea-ice cover. In summary, realistic ice production estimates could be retrieved from our simulations. Neglecting subgrid-scale energy fluxes might considerably underestimate the ice production in coastal polynyas, such as in the Laptev Sea, with possible consequences on the Arctic sea-ice budget.

Lung deposited surface area in Leicester urban background site/UK: Sources and contribution of new particle formation

Lung Deposited Surface Area (LDSA) has been identified as a potential metric for the correlation of a physical aerosol particle properties with health outcomes. Currently, there is little urban LDSA data. As a case study, we investigated measurements of LDSA (alveolar) concentrations in a mid-size European city. LDSA and associated measurements were carried out over 1.5 years at an urban background site in Leicester, UK. Average LDSA concentrations in the cold (November–April) and warm (May–October) seasons of UK were 37 and 23 μm2 cm−3, respectively. LDSA correlates well (R2 = 0.65–0.7, r = 0.77–0.8) with traffic related pollutants, such as equivalent black carbon (eBC) and NOX. We also report for the first time in the UK the correlation between an empirically derived LDSA and eBC. Furthermore, the effect of wind speed and direction on the LDSA was explored. Higher LDSA concentrations are observed at low wind speeds (1–2 m s−1), owing to local traffic emissions. In addition, the diurnal variation of LDSA showed a second peak in the afternoon under warm and relatively clean atmospheric conditions, which can be attributed to photochemical new particle formation (NPF) and growth into the Aitken mode range. These NPF events increased the average background LDSA concentrations from 15.5 to 35.5 μm2 cm−3, although they might not be health-relevant. Overall, the results support the notion that local traffic emissions are a major contributor to observed LDSA concentrations with a clear seasonal pattern with higher values during winter.

GEPS-Based Monthly Prediction at the Canadian Meteorological Centre

AbstractDynamical monthly prediction at the Canadian Meteorological Centre (CMC) was produced as part of the seasonal forecasting system over the past two decades. A new monthly forecasting system, which has been in operation since July 2015, is set up based on the operational Global Ensemble Prediction System (GEPS). This monthly forecasting system is composed of two components: 1) the real-time forecast, where the GEPS is extended to 32 days every Thursday; and 2) a 4-member hindcast over the past 20 years, which is used to obtain the model climatology to calibrate the monthly forecast. Compared to the seasonal prediction system, the GEPS-based monthly forecasting system takes advantage of the increased model resolution and improved initialization.Forecasts of the past 2-yr period (2014 and 2015) are verified. Analysis is performed separately for the winter half-year (November–April), and the summer half-year (May–October). Weekly averages of 2-m air temperature (T2m) and 500-hPa geopotential height (Z500) are assessed. For Z500 in the Northern Hemisphere, limited skill can be found beyond week 2 (days 12–18) in summer, while in winter some skill exists over the Pacific and North American region beyond week 2. For T2m in North America, significant skill is found over a large part of the continent all the way to week 4 (days 26–32). The distribution of the wintertime T2m skill in North America is consistent with the influence of the Madden–Julian oscillation, indicating that a significant part of predictability likely comes from the tropics.

Xylem anatomical traits reveal different strategies of two Mediterranean oaks to cope with drought and warming

Performance and survival of Mediterranean trees depend on their capacity to cope with water stress. In harsh environments, xylem growth strategies are critical to ensure efficient water transport, though these are largely unknown for many species, including most Mediterranean oaks. We investigated xylem anatomical traits in tree-ring series of deciduous Quercus ithaburensis and Q. boissieri in the South-Eastern Mediterranean Basin to assess xylem response to climate variability, with special attention to dry and warm years and to temperature increase over the last decades. Abundant precipitation and low temperature during the wet season (November–April) benefited xylem formation of both species. However, intra-ring analysis revealed different patterns, as the size of early-formed vessels in Q. boissieri was related to previous-year ring, while in Q. ithaburensis it was strongly affected by current wet season conditions. During dry years, vessel size and number in Q. ithaburensis were strongly reduced, but they fully recovered in the following year (high resilience). Conversely, Q. boissieri vessels were barely reduced during dry or warm years (high resistance). Different strategies allow both species to overcome dry and warm years, but their capacity to withstand long-term warming seems to differ. Q. ithaburensis xylem traits did not evidence any trend over the last few decades, while Q. boissieri was facing a decline in some traits. Our analysis suggests that the growth strategies of Q. ithaburensis would be effective under future drier conditions, while temperature increase could induce a hydraulic deterioration and a potential decline in the less fit Q. boissieri.

Plasma 25-Hydroxyvitamin D and Risk of Breast Cancer in Women Followed over 20 Years.

Experimental evidence supports a protective role of 25-hydroxyvitamin D [25(OH)D] in breast carcinogenesis, but epidemiologic evidence is inconsistent. Whether plasma 25(OH)D interacts with breast tumor expression of vitamin D receptor (VDR) and retinoid X receptor-α (RXR) has not been investigated. We conducted a nested case-control study in the Nurses' Health Study, with 1,506 invasive breast cancer cases diagnosed after blood donation in 1989-1990, 417 of whom donated a second sample in 2000-2002. VDR and RXR expression were assessed by immunohistochemical staining of tumor microarrays (n = 669 cases). Multivariate relative risks (RR) and 95% confidence intervals (CI) were calculated using conditional logistic regression. Plasma 25(OH)D levels were not associated with breast cancer risk overall [top (≥32.7 ng/mL) vs. bottom (<17.2 ng/mL) quintile RR = 0.87; 95% CI, 0.67-1.13; P trend = 0.21]. 25(OH)D measured in summer (May-October) was significantly inversely associated with risk (top vs. bottom quintile RR = 0.66; 95% CI, 0.46-0.94; P trend = 0.01); winter levels (November-April) were not (RR = 1.10; 95% CI, 0.75-1.60; P trend = 0.64; P interaction = 0.03). 25(OH)D levels were inversely associated with risk of tumors with high expression of stromal nuclear VDR [≥30 ng/mL vs. <30 ng/mL RR (95% CI): VDR ≥ median = 0.67 (0.48-0.93); VDR < median = 0.98 (0.72-1.35), P heterogeneity = 0.12] and significantly stronger for summer measures (P heterogeneity = 0.01). Associations were not significantly different by RXR expression. No overall association was observed between plasma 25(OH)D and breast cancer risk. However, our results suggest women with high, compared with low, plasma 25(OH)D levels in the summer have a reduced breast cancer risk, and plasma 25(OH)D may be inversely associated with risk of tumors expressing high levels of VDR. Cancer Res; 76(18); 5423-30. ©2016 AACR.