Syndiotactic Polyolefins by Hydrogenation of Highly Stereoregular 1,2 Polydienes: Synthesis and Structural Characterization.

Some syndiotactic-rich polyolefins, generally difficult to synthesize through stereospecific polymerization of the corresponding monomers, were prepared by homogeneous non-catalytic hydrogenation of syndiotactic 1,2 poly(1,3-diene)s with diimide, arising from thermal decomposition of p-toluene-sulfonyl-hydrazide. All the polymers synthesized were structurally characterized by means of several analytical techniques, such as FT-IR, NMR (1H, 13C and 2D), DSC, and GPC, and herein illustrated.

Assessment of nature-based solutions for water resource management in agricultural environments: a stakeholders' perspective in Southern Italy.

This paper explores the potential implementation of Nature-Based Solutions (NBSs) in agriculture, specifically focusing on soil and water management in Southern Italy, particularly in the Apulia and Basilicata regions. Through a tailored questionnaire, it investigates farmers' perceptions of the utility of NBSs, addressing key issues in the region and evaluating their role in addressing soil and water management challenges. Findings reveal primary challenges such as drought, floods, and water pollution, with soil erosion being a major concern. Several NBSs, including wetlands and bioswales, demonstrate consistent utility and performance, while disparities exist for agroforestry and strip cropping. The study underscores a significant gap in the economic valuation of NBSs, emphasizing the need for comprehensive assessments that incorporate livability improvements, water quality enhancement, and socio-cultural benefits. Additionally, an analysis of NBS implementation across Italian agriculture reveals limited case studies, suggesting the need for strategic expansions to meet Sustainable Development Goals. This research offers critical insights into the effectiveness and challenges of NBSs in agricultural soil and water management, advocating for enhanced stakeholder engagement and the development of multidimensional evaluation frameworks to support sustainable practices.

Interferon-Tau in Maternal Peripheral Blood and Its Relationship with Progesterone and Pregnancy-Associated Glycoproteins in the Early Phases of Gestation in Water Buffalo.

The aim of this study was to investigate the interferon tau (IFNt) concentration in the peripheral maternal blood during the early phase of pregnancy in buffalo cows and improve the knowledge on the physiological importance of circulating IFNt, evaluating the possible interaction with pregnancy-associated glycoproteins (PAGs) and progesterone (P4). Blood samples were taken from buffalo cows on day 0 (day of AI), 7, 14, 18, 28, and 40 post insemination for the IFNt, PAG, and P4 analysis and to determine the IFNt mRNA expression. The animals were categorized ex post into Pregnant, Non-pregnant and Embryo mortality groups. The interferon value was influenced by group (p = 0.003), being always higher in pregnant buffalo cows than in non-pregnant ones, while the embryo mortality group showed intermediate values between those for pregnant and non-pregnant animals. The mRNA expression of IFNt was not influenced by groups or any time points. The regression analysis that included IFNt as the independent variable showed that PAGs, from day 18 (p < 0.01), and P4, from day 28 (p < 0.05), were positively associated with IFNt values. The close associations among IFNt, PAGs and P4 demonstrate that all three molecules work together for fetal-placental well-being and pregnancy support. Unfortunately, the great individual variability in circulating IFNt makes this analysis unsuitable for early pregnancy diagnosis.

Modeling pesticides and ecotoxicological risk assessment in an intermittent river using SWAT.

The present work aimed to predict the fate of two pesticides, copper (Cu) and glyphosate in a Mediterranean basin with an intermittent river and to assess the ecotoxicological risk related to their presence in water bodies coupling field measurements of streamflow and pesticide concentrations, and an eco-hydrological model. The Soil and Water Assessment Tool (SWAT) model was calibrated and, subsequently used to assess predicted environmental concentrations of pesticides in surface waters. The ecotoxicological risk related to the presence of Cu and glyphosate in surface water was assessed at the reach scale by using the Toxicity to Exposure Ratio approach (TER). Measurements of glyphosate concentrations (< 0.5 µg l-1) exceeded the maximum European threshold of environmental quality standards for pesticides (EQS) of 0.1 µg l-1. High concentrations of glyphosate were predicted in the wet season and in September, when glyphosate is mostly used in vineyards and olive grove productions. Acute risk (TER < 100) associated with the presence of glyphosate was detected for several reaches. High concentrations of Cu (< 6.5 µg l-1), mainly used as a fungicide in vineyards, were predicted in several river reaches. The results of the ecotoxicological risk assessment revealed that November and January were the critical months during which most of the river reaches showed a chronic risk associated with the presence of Cu.

Ethylene-alt-α-Olefin Copolymers by Hydrogenation of Highly Stereoregular cis-1,4 Polydienes: Synthesis and Structural Characterization.

The homogeneous non-catalytic hydrogenation of several types of iso- and syndiotactic cis-1,4 poly(1,3-diene)s with diimide, formed by thermal decomposition of p-toluene-sulfonyl-hydrazide, was examined. Perfectly alternating ethylene/1-alkene copolymers having different tacticity (i.e., isotactic and syndiotactic), which in some cases are difficult to synthesize by simple stereospecific co-polymerization of the corresponding monomers, were obtained. All the copolymers synthesized were fully characterized from a structural, morphological, and rheological point of view through different analytical techniques (FT-IR, NMR, GPC, DSC, RX).

Ecological flow in southern Europe: Status and trends in non-perennial rivers.

The concept of environmental flows (E-Flows) describes the streamflow that is necessary to maintain river ecosystems. Although a large number of methods have been developed, a delay was recorded in implementing E-Flows in non-perennial rivers. The general aim of the paper was to analyse the criticalities and the current state of implementation of the E-Flows in non-perennial rivers of southern Europe. The specific objectives were to analyse (i) the European Union (EU) and national legislation on E-Flows, and (ii) the methodologies currently adopted for setting E-Flows in non-perennial rivers in the EU Member States (MSs) of the Mediterranean Region (Spain, Greece, Italy, Portugal, France, Cyprus, and Malta). From the analysis of national legislations, it is possible to acknowledge a step forward toward regulatory unification at the European level, on the subject of E-Flows and more generally toward the protection of aquatic ecosystems. The definition of E-Flows, for most countries, has abandoned the idea of a regime of constant and minimal flow, but it recognizes the importance of the biological, and chemical-physical aspects connected to it. From the analysis of the E-Flows implementation through the review of the case studies, one can surmise that in non-perennial rivers the E-Flows science is still an emerging discipline. The limited availability of hydrological, hydraulic, and biological data as well as the restricted economic resources allocated for managing non-perennial rivers are the main causes of the delay in the E-Flows implementation in MSs. The results of the present study may contribute in setting an E-Flow regime in non-perennial rivers.

Fine Cocoa Fermentation with Selected Lactic Acid Bacteria: Fermentation Performance and Impact on Chocolate Composition and Sensory Properties.

Cocoa fermentation is a central step in chocolate manufacturing. In this research, we performed controlled fermentations of a fine cocoa variety to evaluate the impact of adjunct cultures of selected lactic acid bacteria (LAB) on fermentation parameters, chemical composition, and sensory profile of fine cocoa and chocolate. Improved fermentation processes were carried out at the Centre for the Integral Transformation of Cacao (CETICO) in Dominican Republic. Two strains of LAB, previously isolated from cocoa, and belonging to Lactiplantibacillus fabifermentans and Furfurilactibacillus rossiae species, were employed. Fermentation parameters, protein, peptide and free amino acid profiles of the fermented cocoa and volatile molecules were determined. Sensory analysis of the derived chocolate was also carried out. The obtained results indicated that the addition of the adjunct cultures influences the proteolytic processes and the free amino acid profile. Finally, the adjunct cultures increased the complexity of the flavour profile of the chocolate as they received a higher score for descriptors commonly used for fine chocolate, such as honey and red fruits. The results obtained showed that the selected strains can be an added value to the development of specific flavours that are desirable at industrial level.

Dichloro(2,2'-bipyridine)copper/MAO: An Active and Stereospecific Catalyst for 1,3-Diene Polymerization.

Dichloro(2,2'-bipyridine)copper was synthesized by reacting copper dichloride with bypyridine, and its behavior, in combination with methylaluminoxane (MAO), in the polymerization of butadiene, isoprene, 2,3-dimethyl-1,3 butadiene, and 3-methyl-1,3-pentadiene was examined. The purpose of this study is to find catalytic systems that are more sustainable than those currently used for the polymerization of butadiene and isoprene (e.g., Co and Ni), but that are comparable in terms of catalytic activity and selectivity. Predominantly, syndiotactic 1,2 polybutadiene, crystalline syndiotactic 3,4 polyisoprene, crystalline syndiotactic 1,2 poly(3-methyl-1,3-pentadiene), and crystalline cis-1,4 poly(2,3-dimethyl-1,3-butadiene) were obtained in a manner similar to that observed with the analogous iron complex. As far as we know, the investigated catalytic system represents the first example of a copper-based catalyst in the field of stereospecific polymerization. Given the great availability of copper, its extremely low toxicity (and therefore high sustainability), and the similarity of its behavior to that of iron, the result obtained seems to us of considerable interest and worthy of further investigation.

Exploration of Lactiplantibacillus fabifermentans and Furfurilactobacillus rossiae as potential cocoa fermentation starters.

AIMS: To investigate the characteristics of two minority autochthonous LAB species, with particular regard to those properties that could be exploited in an improved cocoa fermentation process from a quality and safety point of view. METHODS AND RESULTS: Bacterial, yeast and mould strains characteristic of spontaneously fermented Dominican cocoa beans were isolated and identified by 16S or 26S rRNA gene sequencing. The potential of two autochthonous strains of LAB belonging to the species Lactiplantibacillus fabifermentans and Furfurilactibacillus rossiae were investigated. The two selected LAB strains were able to utilize glucose and fructose, produced mainly D-L lactic acid and had a good ability to resist to cocoa-related stress conditions such as low pH, high temperature and high osmotic pressure, as well as to grow in sterile cocoa pulp. The strains did not inhibit the growth of yeasts and acetic acid bacteria, that are essential to the cocoa fermentation process, and possessed a complex pool of peptidases especially active on hydrophobic amino acids. The strains also showed antifungal activity against mould species that can be found at the final stages of cocoa fermentation, as Aspergillus tamarii, A. nidulans, Lichtheimia ornata and Rhizomucor pusillus. CONCLUSIONS: The tested strains are good candidates for the design of starter cultures for a controlled cocoa fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY: This research showcases the potential of two alternative LAB species to the dominating Lactiplantibacillus plantarum and Limosilactibacillus fermentum as cocoa fermentation starters, with an interesting activity in improving the safety and quality of the process.

Pathogenetic Interplay Between IL-6 and Tryptophan Metabolism in an Experimental Model of Obesity.

Obesity is a metabolic disease characterized by a state of chronic, low-grade inflammation and dominated by pro-inflammatory cytokines such as IL-6. Indoleamine 2,3-dioxygenase 1 (IDO1) is an enzyme that catalyzes the first step in the kynurenine pathway by transforming l-tryptophan (Trp) into l-kynurenine (Kyn), a metabolite endowed with anti-inflammatory and immunoregulatory effects. In dendritic cells, IL-6 induces IDO1 proteasomal degradation and shuts down IDO1-mediated immunosuppressive effects. In tumor cells, IL-6 upregulates IDO1 expression and favors tumor immune escape mechanisms. To investigate the role of IDO1 and its possible relationship with IL-6 in obesity, we induced the disease by feeding mice with a high fat diet (HFD). Mice on a standard diet were used as control. Experimental obesity was associated with high IDO1 expression and Kyn levels in the stromal vascular fraction of visceral white adipose tissue (SVF WAT). IDO1-deficient mice on HFD gained less weight and were less insulin resistant as compared to wild type counterparts. Administration of tocilizumab (TCZ), an IL-6 receptor (IL-6R) antagonist, to mice on HFD significantly reduced weight gain, controlled adipose tissue hypertrophy, increased insulin sensitivity, and induced a better glucose tolerance. TCZ also induced a dramatic inhibition of IDO1 expression and Kyn production in the SVF WAT. Thus our data indicated that the IL-6/IDO1 axis may play a pathogenetic role in a chronic, low-grade inflammation condition, and, perhaps most importantly, IL-6R blockade may be considered a valid option for obesity treatment.

Some Novel Cobalt Diphenylphosphine Complexes: Synthesis, Characterization, and Behavior in the Polymerization of 1,3-Butadiene.

Some novel cobalt diphenylphosphine complexes were synthesized by reacting cobalt(II) chloride with (2-methoxyethyl)diphenylphosphine, (2-methoxyphenyl)diphenylphosphine, and 2-(1,1-dimethylpropyl)-6-(diphenylphosphino)pyridine. Single crystals suitable for X-ray diffraction studies were obtained for the first two complexes, and their crystal structure was determined. The novel compounds were then used in association with methylaluminoxane (MAO) for the polymerization of 1,3-butadiene, and their behavior was compared with that exhibited in the polymerization of the same monomer by the systems CoCl2(PnPrPh2)2/MAO and CoCl2(PPh3)2/MAO. Some significant differences were observed depending on the MAO/Co ratio used, and a plausible interpretation for such a different behavior is proposed.

Physiological performance of Kazachstania unispora in sourdough environments.

In this work we explored the potential of several strains of Kazachstania unispora to be used as non-conventional yeasts in sourdough fermentation. Properties such as carbohydrate source utilization, tolerance to different environmental factors and the performance in fermentation were evaluated. The K. unispora strains are characterized by rather restricted substrate utilization: only glucose and fructose supported the growth of the strains. However, the growth in presence of fructose was higher compared to a Saccharomyces cerevisiae commercial strain. Moreover, the inability to ferment maltose can be considered a positive characteristic in sourdoughs, where the yeasts can form a nutritional mutualism with maltose-positive Lactic Acid Bacteria. Tolerance assays showed that K. unispora strains are adapted to a sourdough environment: they were able to grow in conditions of high osmolarity, high acidity and in presence of organic acids, ethanol and salt. Finally, the performance in fermentation was comparable with the S. cerevisiae commercial strain. Moreover, the growth was more efficient, which is an advantage in obtaining the biomass in an industrial scale. Our data show that K. unispora strains have positive properties that should be explored further in bakery sector.

Soil erosion modelling: A bibliometric analysis.

Soil erosion can present a major threat to agriculture due to loss of soil, nutrients, and organic carbon. Therefore, soil erosion modelling is one of the steps used to plan suitable soil protection measures and detect erosion hotspots. A bibliometric analysis of this topic can reveal research patterns and soil erosion modelling characteristics that can help identify steps needed to enhance the research conducted in this field. Therefore, a detailed bibliometric analysis, including investigation of collaboration networks and citation patterns, should be conducted. The updated version of the Global Applications of Soil Erosion Modelling Tracker (GASEMT) database contains information about citation characteristics and publication type. Here, we investigated the impact of the number of authors, the publication type and the selected journal on the number of citations. Generalized boosted regression tree (BRT) modelling was used to evaluate the most relevant variables related to soil erosion modelling. Additionally, bibliometric networks were analysed and visualized. This study revealed that the selection of the soil erosion model has the largest impact on the number of publication citations, followed by the modelling scale and the publication's CiteScore. Some of the other GASEMT database attributes such as model calibration and validation have negligible influence on the number of citations according to the BRT model. Although it is true that studies that conduct calibration, on average, received around 30% more citations, than studies where calibration was not performed. Moreover, the bibliographic coupling and citation networks show a clear continental pattern, although the co-authorship network does not show the same characteristics. Therefore, soil erosion modellers should conduct even more comprehensive review of past studies and focus not just on the research conducted in the same country or continent. Moreover, when evaluating soil erosion models, an additional focus should be given to field measurements, model calibration, performance assessment and uncertainty of modelling results. The results of this study indicate that these GASEMT database attributes had smaller impact on the number of citations, according to the BRT model, than anticipated, which could suggest that these attributes should be given additional attention by the soil erosion modelling community. This study provides a kind of bibliographic benchmark for soil erosion modelling research papers as modellers can estimate the influence of their paper.

Soil erosion modelling: A global review and statistical analysis.

To gain a better understanding of the global application of soil erosion prediction models, we comprehensively reviewed relevant peer-reviewed research literature on soil-erosion modelling published between 1994 and 2017. We aimed to identify (i) the processes and models most frequently addressed in the literature, (ii) the regions within which models are primarily applied, (iii) the regions which remain unaddressed and why, and (iv) how frequently studies are conducted to validate/evaluate model outcomes relative to measured data. To perform this task, we combined the collective knowledge of 67 soil-erosion scientists from 25 countries. The resulting database, named 'Global Applications of Soil Erosion Modelling Tracker (GASEMT)', includes 3030 individual modelling records from 126 countries, encompassing all continents (except Antarctica). Out of the 8471 articles identified as potentially relevant, we reviewed 1697 appropriate articles and systematically evaluated and transferred 42 relevant attributes into the database. This GASEMT database provides comprehensive insights into the state-of-the-art of soil- erosion models and model applications worldwide. This database intends to support the upcoming country-based United Nations global soil-erosion assessment in addition to helping to inform soil erosion research priorities by building a foundation for future targeted, in-depth analyses. GASEMT is an open-source database available to the entire user-community to develop research, rectify errors, and make future expansions.

Using water footprint concepts for water security assessment of a basin under anthropogenic pressures.

The evaluation of water shortages and pollution levels is crucial for watershed management and sustainable development. This paper proposes a water footprint (WF) sustainability assessment approach to analyse water security in a river basin under human pressures. The methodology involves a comprehensive assessment of the current water security at different spatial and temporal levels, and identifies suitable response formulations to achieve sustainability. Field surveys and measurements (streamflow, water quality) were carried out, and the Soil and Water Assessment Tool model was used for assessing water balance components and water quality. The study was carried out in the Canale d'Aiedda river basin (Taranto, Italy), which is part of the 'area of environmental crisis' of Taranto, which requires remediation of surface water, groundwater, soil and subsoil. Considering all the anthropogenic activities in the basin, including agriculture and the treated effluent disposed of via wastewater treatment plants (WWTPs), the average WF was 213.9 Mm3 y-1, of which 37.2%, 9.2% and 53.6% comprised respectively for WFgreen, WFblue and WFgrey. The WF sustainability assessment revealed that pollution was the main factor affecting surface water security. In particular, point sources contributed with 90% to the total WFgrey, and lower pollutant thresholds should be fixed for effluent from WWTPs in order to increase water quality of the receiving water body. In addition, for assuring water security the extension of the natural areas should be increased to support biodiversity in the river basin and soil management strategies should be improved to allow more water to be retained in the soil and to reduce nutrients in surface runoff. This study demonstrates that the WF sustainability assessment is a feasible approach for integrated water resources management, as well as offering a much broader perspective on how water security can be achieved in a Mediterranean basin affected by multiple anthropogenic stressors.

Efficacy and Safety of Direct Oral Anticoagulants in Patients With Atrial Fibrillation and High Thromboembolic Risk. A Systematic Review.

Background: The aim of the study was to evaluate the efficacy and safety of direct oral anticoagulants (DOACs) in a subgroup of patients with atrial fibrillation (AF), CHADS2 score ≥3, advanced age, and heart failure (HF) coming from the main DOACs randomized clinical trials. Methods: We searched MEDLINE, MEDLINE In-Process, and Other Non-Indexed Citations, EMBASE, PubMed, and the Cochrane Central Register of Controlled Trials. English-language articles published from 2002 to March 2019 dealing with DOACs for preventing thrombotic events in AF were considered. We did not conduct any statistical analyses, as indirect comparison between DOACs represents hypothesis generators. Results: This systematic review was restricted to the subgroup of patients with CHADS2 score ≥3 (n = 31,203), elderly (n = 24,788), and with HF (n = 29,297) derived from the pivotal trials. Risk index (RI) was calculated. The RI for stroke/systemic embolism was similar in all of the patients treated with DOACs or warfarin. The lowest RI was in rivaroxaban patients (CHADS2 score ≥3: RI = 0.04; elderly: RI = 0.09; HF: RI = 0.05). The RIs for bleeding were higher in patients treated with dabigatran (CHADS2 score ≥3: RI110 = 0.23; elderly: RI110 = 0.22; HF: RI110 = 0.16; CHADS2score ≥3: RI150 = 0.30; elderly: RI150 = 0.24; HF: RI150 = 0.16). The bleeding RIs were higher with apixaban (CHADS2 score ≥3: RI = 0.23; elderly: RI = 0.25; HF: RI = 0.14) and dabigatran (CHADS2 score ≥3: RI = 0.28; elderly: RI = 0.21; HF: RI = 0.19). Conclusions: The use of DOACs is a reasonable alternative to vitamin K antagonists in AF patients with CHADS2 score ≥3, advanced age, and HF. The RI constitutes a useful, additional tool to facilitate clinicians in choosing DOACs or warfarin in particular category of AF patients.

Development of a milk-based medium for the selection of urease-defective mutants of Streptococcus thermophilus.

Streptococcus thermophilus strains are used in fermented dairy products for their capacity to metabolize lactose into lactic acid. The rate of lactic acid production in milk is of major economic importance, as rapid acidification prevents growth of undesirable microorganisms. It is also of paramount significance for aroma, texture and flavor of the end product. Besides achieving customer satisfaction, improvement of production rate and operational costs incite industrials into selecting fast acidifying strains. Another important trait of S. thermophilus influencing acidification is the urease, which catabolizes urea into ammonia and has a detrimental effect on acidification. Unfortunately, most of the S. thermophilus strains possess the urease, and the urease-negative ones are necessary for industrial applications. Urease activity is a widely distributed activity in S. thermophilus species, and urease-negative strains are rare. The later are however interesting from an industrial point of view, as they may give faster acidification in dairy applications, because lactic acid is not buffered by urea-derived ammonia. Nowadays, the efforts to improve the characteristics of strains for industrial applications are based on natural strategies such as random mutagenesis. This implies the need of a screening method that is efficient in terms of time and success. In this context, the aim of this study was the development of a new medium that allows selection of urease-defective mutants based on S. thermophilus colony morphology. Discrimination capacity of the new medium was verified using previously characterized urease-negative recombinant strains. The new milk-based medium, applied to industrial S. thermophilus strains subjected to UV mutagenesis, allowed the selection of 3 mutants, partially or completely defective in urease activity. Genetic characterization of urease-defective mutants highlighted the presence of nonsense or missense mutations in the ureA, ureC and ureG genes, thus supporting their phenotype. Evaluation of milk acidification revealed increased performance for one out of three urease-defective mutants compared to wild-type strains.

Homo- and Copolymerization of Ethylene with Norbornene Catalyzed by Vanadium(III) Phosphine Complexes.

Herein, we report the homo- and co-polymerization of ethylene (E) with norbornene (NB) catalyzed by vanadium(III) phosphine complexes of the type VCl3(PMenPh3-n)2 [n = 2 (1a), 1 (1b)] and VCl3(PR3)2 [R = phenyl (Ph, 1c), cyclohexyl (Cy, 1d), tert-butyl (tBu, 1e)]. In the presence of Et2AlCl and Cl3CCOOEt (ETA), 1a-1e exhibit good activities for the polymerization of ethylene, affording linear, semicrystalline PEs with a melting temperature of approximately 130 °C. Mainly alternating copolymers with high comonomer incorporation were obtained in the E/NB copolymerization. A relationship was found between the electronic and steric properties of the phosphine ligands and the catalytic performance. Overall, the presence of electron-withdrawing ligand substituents increases the productivity, complexes with aryl phosphine (weaker σ-donor character) exhibiting a higher (co)polymerization initiation rate than those with alkyl phosphines (stronger σ-donor character). Steric effects also seem to play a key role since 1d and 1e, having large size phosphines (PCy3 θ = 170° and PtBu3 θ = 182°, respectively) are more active than 1a (PMe2Ph θ = 122°). In this case, the larger size of PtBu3 and PCy3 likely compensates for their higher donor strength compared to PMe2Ph.

Novel Cobalt Dichloride Complexes with Hindered Diphenylphosphine Ligands: Synthesis, Characterization, and Behavior in the Polymerization of Butadiene.

Two novel cobalt diphenylphosphine complexes were synthesized by reacting cobalt(II) chloride with tert-butyl(diphenyl)phosphine (PtBuPh2) and (S)-(+)neomenthyldiphenylphosphine [(S)-NMDPP]. The crystal structure of the former was determined by single-crystal X-ray diffraction studies. The two complexes were then used in combination with methylaluminoxane (MAO) for the polymerization of 1,3-butadiene: crystalline highly syndiotactic 1,2 poly(1,3-butadiene)s were obtained, with a 1,2 content and a syndiotactic index (percentage of syndiotactic triads [rr]) up to 95% and 85%, respectively. The results obtained further support and confirm what was already observed in the polymerization of 1,3-butadiene with CoCl2(PRPh2)2-MAO (R = methyl, ethyl, normal-propyl, iso-propyl, and cyclohexyl): the nature of the phosphine ligand strongly affects the polymerization stereoselectivity, the polymer syndiotacticity increasing with increasing phosphine ligand steric hindrance.

Effect of check dams on riparian vegetation cover: A multiscale approach based on field measurements and satellite images for Leaf Area Index assessment.

This study aims to detect the variability of riparian vegetation by means of in-situ measurements of the Leaf Area Index (LAI) and its retrieval from Landsat 8 satellite images in a Mediterranean stream ('Cammarota', Puglia region, Southern Italy) characterized by the presence of intact and destroyed check dams. Fifty-three transects were measured using a Plant Canopy Analyzer and a broad range of LAI values (0.26-5.71) was observed. Lower values were found in Cammarota reaches with damaged or destroyed check dams that led to active erosive processes, whereas higher LAI values were detected in the reaches with greater geomorphological stability. These results were confirmed by the analysis of a nearby stream ('Vallone della Madonna') with intact check dams and sound riparian vegetation which produced a higher range (4.08-5.93) of LAI values. The LAI values of riparian vegetation in both streams were compared with those found in more homogeneous types of vegetation (wheat field and deciduous forest) in the surrounding areas, which were used as control plots. Landsat 8 satellite images relating to the same period of field activity were also analyzed, and the performance of three equations for deriving LAI values from the corrected Normalized Difference Vegetation Index (NDVI) was evaluated. The Lambert-Beer equation gave the best statistical performance for predicting LAI within the reaches of the Cammarota stream with a denser vegetation, as well as in the Vallone della Madonna stream and deciduous forest. The significant variability of the observed LAI values in the Cammarota reach subject to initial erosive processes, was not detected by any of the equations applied.