ALBERT

Beschreibung: Eight months (June 2011-January 2012) of aerosol property data were obtained at the remote site of Alborán Island (35.95 ° N, 3.03 ° W) in the western Mediterranean basin. The aim of this work is to assess the aerosol properties according to air-mass origin and transport over this remote station with a special focus on air mass transport from North Africa. For air masses coming from North Africa, different aerosol properties showed strong contributions from mineral dust lifted from desert areas. Nevertheless, during these desert dust intrusions, some atmospheric aerosol properties are clearly different from pure mineral dust particles. Thus, Angström exponent α(440–870) presents larger values than those reported for pure desert dust measured close to dust source regions. These results combine with α(440,670)-α(670,870) ≥ 0.1 and low single scattering albedo (ω(λ)) values, especially at the largest wavelengths. Most of the desert dust intrusions over Alborán can be described as a mixture of dust and anthropogenic particles. The analyses support that our results apply to North Africa desert dust air masses transported from different source areas. Therefore, our results indicate a significant contribution of fine absorbing particles during desert dust intrusions over Alborán arriving from different source regions. The aerosol optical depth (AOD) data retrieved from sun-photometer measurements have been used to check MODIS retrievals, and they show reasonable agreement, especially for North African air masses.

Beschreibung: In recent years there has been an increase in research to understand how global changes’ impacts on soil biota translate into altered ecosystem functioning. However, results vary between global change effects, soil taxa and ecosystem processes studied, and a synthesis of relationships is lacking. Therefore, here we initiate such a synthesis to assess whether the effect size of global change drivers (elevated CO 2 , N deposition and warming) on soil microbial abundance is related with the effect size of these drivers on ecosystem functioning (plant biomass, soil C cycle and soil N cycle) using meta-analysis and structural equation modeling. For N deposition and warming, the global change effect size on soil microbes was positively associated with the global change effect size on ecosystem functioning, and these relationships were consistent across taxa and ecosystem processes. However, for elevated CO 2 , such links were more taxon and ecosystem process specific. For example, fungal abundance responses to elevated CO 2 were positively correlated with those of plant biomass but negatively with those of the N cycle. Our results go beyond previous assessments of the sensitivity of soil microbes and ecosystem processes to global change, and demonstrate the existence of general links between the responses of soil microbial abundance and ecosystem functioning. Further we identify critical areas for future research, specifically altered precipitation, soil fauna, soil community composition, and litter decomposition, that are need to better quantify the ecosystem consequences of global change impacts on soil biodiversity. This article is protected by copyright. All rights reserved.

Beschreibung: The differential distribution of diatoms and dinoflagellates in the Bay of La Paz, Gulf of California, Mexico, was analyzed in summer of 2009, when a cyclonic eddy confined in the bay dominated the circulation. An uplift of the nutricline in the eddy drove high concentrations of nutrients to the euphotic layer. A differential phytoplankton distribution was observed to be associated with the eddy: there was an abundance of dinoflagellates close to the center of the cyclonic eddy, whereas diatoms were more abundant at the periphery. A significant inverse correlation (R=-0.62, p〈0.002) was found between temperature at 25 m depth and dinoflagellates abundance. Based on the temporal evolution of chlorophyll measured by MODIS satellite images, and a conceptual model proposed for the lifecycle of eddies, the cyclonic eddy may have been an old decaying structure. The effect of the cyclonic eddy on the phytoplankton distribution in this small semi-enclosed region was apparently similar to that found in larger eddies in the open ocean, but this is the first time such a differential distribution has been found associated to a confined eddy.

Beschreibung: Palladium doped ZnO was prepared by the sol-gel and dip-coating techniques, starting with zinc acetate and palladium chloride as precursors, followed by its hydrolysis in methanol. Acetic acid was incorporated to adjust pH, as well as acetylacetonate and monoehtylamine as stabilizers. The sol was later dipped 3 times in silica substrates. Structural, morphological, and antimicrobial properties of the films were investigated for three palladium contents (1.0, 2.5, and 5 mol %). X-ray diffraction (XRD) showed that the films have a hexagonal structure after been annealed at 500°C. X-Ray photoelectron Spectroscope (XPS) showed that Pd is present in its oxidized form. Atomic force microscopy (AFM) from films showed a crack free and smooth surface (Ra= 18 nm), composed of cross-linked particles. The synthesized films presented antibacterial activity against Escherichia coli and Pseudomona aeruginosa . It was observed that the higher Pd content (5 mol %) presents the higher antimicrobial ratio, 64.07%, for the E. coli , whereas for the P. aeruginosa , the lower Pd content (1 mol %), shows the higher antimicrobial ratio, 76.43%.

Beschreibung: Radar-based estimates of rainfall are affected by many sources of uncertainties which would propagate through the hydrological model when radar rainfall estimates are used as input or initial conditions. An elegant solution to quantify these uncertainties is to model the empirical relationship between radar measurements and rain gauge observations (as the ‘ground reference). However, most current studies only use a fixed and uniform model to represent the uncertainty of radar rainfall, without consideration of its variation under different synoptic regimes. Wind is such a typical weather factor, as it not only induces error in rain gauge measurements, but also causes the raindrops observed by weather radar to drift when they reach the ground. For this reason, as a first attempt, this study introduces the wind field into the uncertainty model and designs the radar rainfall uncertainty model under different wind conditions. We separate the original dataset into three subsamples according to wind speed, which are named as WDI (0–2 m/s), WDII (2–4 m/s) and WDIII (〉4 m/s). The multivariate distributed ensemble generator (MDEG) is introduced and established for each subsample. 30 typical events (10 at each wind range) are selected to explore the behaviors of uncertainty under different wind ranges. In each time step, 500 ensemble members are generated and the values of 5 th to 95 th percentile values are used to produce the uncertainty bands. Two basic features of uncertainty bands, namely dispersion and ensemble bias, increase significantly with the growth of wind speed, demonstrating that wind speed plays a considerable role in influencing the behavior of the uncertainty band. Based on these evidences, we conclude that the radar rainfall uncertainty model established under different wind conditions should be more realistic in representing the radar rainfall uncertainty. This study is only a start in incorporating synoptic regimes into rainfall uncertainty analysis and a great deal of more effort is still needed to build a realistic and comprehensive uncertainty model for radar rainfall data. This article is protected by copyright. All rights reserved.

Beschreibung: Understanding how climate change can affect crop-pollinator systems helps predict potential geographical mismatches between a crop and its pollinators, and therefore identify areas vulnerable to loss of pollination services. We examined the distribution of orchard species (apples, pears, plums and other top fruits) and their pollinators in Great Britain, for present and future climatic conditions projected for 2050 under the SRES A1B Emissions Scenario. We used a relative index of pollinator availability as a proxy for pollination service. At present there is a large spatial overlap between orchards and their pollinators, but predictions for 2050 revealed that the most suitable areas for orchards corresponded to low pollinator availability. However, we found that pollinator availability may persist in areas currently used for fruit production, but which are predicted to provide sub-optimal environmental suitability for orchard species in the future. Our results may be used to identify mitigation options to safeguard orchard production against the risk of pollination failure in Great Britain over the next 50 years; for instance choosing fruit tree varieties that are adapted to future climatic conditions, or boosting wild pollinators through improving landscape resources. Our approach can be readily applied to other regions and crop systems, and expanded to include different climatic scenarios. This article is protected by copyright. All rights reserved.

Beschreibung: Phosphorus (P) is a major plant nutrient, however, its availability in volcanic ash soils is presumed to be small, due to its specific sorption on short-range order minerals. We analyzed distinct P fractions in volcanic ash soils of different age (60 to 〉 100,000 y BP) under pine forests in Central Mexico to investigate their changes along a chronosequence of Regosols, Andosols, and Lixisols, and to evaluate if P availability limits tree growth at any particular stage. Top soil and subsoil samples were first analyzed by the Tiessen and Moir method, which failed to extract exhaustively “organic” and “occluded P”, and “P associated with apatite”. Therefore, we modified the fractionation scheme by including a “recalcitrant organic P” fraction obtained from the difference between P determined in air-dried subsamples and subsamples burned at 300°C; P adsorbed to short-range order minerals was assessed in an extraction with NH 4 -oxalate, and P in primary minerals by subtracting the sum of all other fractions from total P contents determined by XRF. This we did after discovering that primary P occurred in the form of fluorapatite included in plagioclase, volcanic glass or olivine. We also measured P contents in pine needles and related these with the “mobile soil P” fractions. The results show that “organic P” reaches maximum contents in 10,000-y old soil, as does P associated with short-range order minerals, while P occluded into crystalline oxides increases constantly over time. After 100,000 y, 31% of total P still remains in the form of primary P in A horizons. “Mobile P” was constant 〉 40 mg kg −1 in Regosols and Andosols and related positively with foliar P contents, which were within adequate nutritional ranges. Only in Lixisols small “mobile P” concentrations in soil correspond with inadequate P contents in pine needles.

Beschreibung: P2X7 is a purinergic receptor-channel; its activation by ATP elicits a broad set of cellular actions, from apoptosis to signals for survival. Here, P2X7 expression and function was studied in human ovarian carcinoma (OCA) cells, and biopsies from non-cancerous and cancer patients were analyzed by immunohistochemistry. Ovarian surface epithelium in healthy tissue expressed P2X7 at a high level that was maintained throughout the cancer. The cell lines SKOV-3 and CAOV-3 were used to investigate P2X7 functions in OCA. In SKOV-3 cells, selective stimulation of P2X7 by 2′(3′)-O-(4-benzoylbenzoyl) adenosine-5′-triphosphate (BzATP) induced a dose-dependent increase of intracellular Ca 2+ concentration ([Ca 2+ ] i ) but not cell death. Instead, BzATP increased the levels of phosphorylated ERK and AKT (pERK and pAKT), with an EC 50 of 44 ± 2 and 1.27 ± 0.5 μM, respectively; 10 μM BzATP evoked a maximum effect within 15 min that lasted for 120 min. Interestingly, basal levels of pERK and pAKT were decreased in the presence of apyrase in the medium, strongly suggesting an endogenous, ATP-mediated phenomenon. Accordingly: (i) mechanically stimulated cells generated a [Ca 2+ ] i increase that was abolished by apyrase; (ii) apyrase induced a decrease in culture viability, as measured by the MTS assay for mitochondrial activity; (iii) incubation with 10 μM AZ10606120, a specific P2X7 antagonist and transfection with the dominant negative P2X7 mutant E496A, both reduced cell viability to 70.1 ± 8.9% and to 76.5 ± 5%, respectively, of control cultures. These observations suggested that P2X7 activity was auto-induced through ATP efflux; this increased pERK and pAKT levels that generated a positive feedback on cell viability. © 2014 Wiley Periodicals, Inc.