High Temperature and Humidity Affect Pollen Viability and Longevity in Olea europaea L.

Olea europaea L. is a crop typical of the Mediterranean area that has an important role in economy, society, and culture of this region. Climate change is expected to have significant impact on this crop, which is typically adapted to certain pedo-climatic characteristics of restricted geographic areas. In this scenario, the aim of this study was to evaluate the time-course response of pollen viability to different combinations of temperature and humidity. The study was performed comparing flowering time and pollen functionality of O. europaea from twelve cultivars growing at the same site belonging to the Campania olive collection in Italy. Pollen was incubated at 12 °C, 22 °C, and 36 °C in combination with 50% RH or 100% RH treatments for 5 days. The results highlighted that a drastic loss of pollen viability occurs when pollen is subjected to a combination of high humidity and high temperature, whereas 50% RH had less impact on pollen thermotolerance, because most cultivars preserved a high pollen viability over time. In the ongoing climate change scenario, it is critical to assess the effect of increasing temperatures on sensitive reproductive traits such as pollen viability to predict possible reduction in crop yield. Moreover, the results highlighted that the effect of temperature increase on pollen thermotolerance should be evaluated in combination with other environmental factors such as humidity conditions. The screening of olive cultivars based on pollen thermotolerance is critical in the ongoing climate change scenario, especially considering that the economic value of this species relies on successful fertilization and embryo development, and also that production cycle of Olea europaea can be longer than a hundred years

Identificação de outliers em dados de precificação de ativos com um novo estimador de forward search ponderado

O objetivo deste trabalho é apresentar o método Forward Search Ponderado (FSW) para a detecção de valores discrepantes (outliers) nos dados de precificação de ativos. Esse novo estimador, baseado em um algoritmo que reduz o peso das observações mais anômalas do conjunto de dados, é testado utilizando dados simulados e empíricos de precificação de ativos. O impacto dos outliers na estimativa de modelos de precificação de ativos é avaliado em diferentes cenários, e os resultados são avaliados com testes estatísticos associados, com base nessa nova abordagem. Nossa proposta gera um procedimento alternativo para uma estimativa robusta dos betas da carteira, permitindo a comparação entre modelos concorrentes de precificação de ativos. O algoritmo, eficiente e robusto para outliers, é utilizado para fornecer estimativas robustas dos parâmetros dos modelos em uma comparação com os métodos tradicionais de estimativa econométrica geralmente utilizados na literatura. Em particular, a precisão dos alfas é significantemente aumentada quando o método Forward Search (FS) é utilizado. Utilizamos simulações de Monte Carlo e também o conhecido conjunto de dados de fatores de retornos acionários, fornecido pelo Prof. Kenneth French, que consiste em 25 carteiras Fama-French no mercado acionário dos Estados Unidos, utilizando modelos de um e três fatores, em base mensal e anual. Nossos resultados indicam que a rejeição marginal do modelo de três fatores de Fama-French é influenciada pela presença de outliers nas carteiras, ao utilizar retornos mensais. Em dados anuais, o uso de métodos robustos aumenta o nível de rejeição de alfas nulos no Modelo de Precificação de Ativos de Capital (Capital Asset Pricing Model –CAPM) e no modelo de três fatores de Fama-French, com estimativas mais eficientes na ausência de outliers, e alfas consistentes quando os outliers estão presentes.O objetivo deste trabalho é apresentar o método Forward Search Ponderado (FSW) para a detecção de valores discrepantes (outliers) nos dados de precificação de ativos. Esse novo estimador, baseado em um algoritmo que reduz o peso das observações mais anômalas do conjunto de dados, é testado utilizando dados simulados e empíricos de precificação de ativos. O impacto dos outliers na estimativa de modelos de precificação de ativos é avaliado em diferentes cenários, e os resultados são avaliados com testes estatísticos associados, com base nessa nova abordagem. Nossa proposta gera um procedimento alternativo para uma estimativa robusta dos betas da carteira, permitindo a comparação entre modelos concorrentes de precificação de ativos. O algoritmo, eficiente e robusto para outliers, é utilizado para fornecer estimativas robustas dos parâmetros dos modelos em uma comparação com os métodos tradicionais de estimativa econométrica geralmente utilizados na literatura. Em particular, a precisão dos alfas é significantemente aumentada quando o método Forward Search (FS) é utilizado. Utilizamos simulações de Monte Carlo e também o conhecido conjunto de dados de fatores de retornos acionários, fornecido pelo Prof. Kenneth French, que consiste em 25 carteiras Fama-French no mercado acionário dos Estados Unidos, utilizando modelos de um e três fatores, em base mensal e anual. Nossos resultados indicam que a rejeição marginal do modelo de três fatores de Fama-French é influenciada pela presença de outliers nas carteiras, ao utilizar retornos mensais. Em dados anuais, o uso de métodos robustos aumenta o nível de rejeição de alfas nulos no Modelo de Precificação de Ativos de Capital (Capital Asset Pricing Model –CAPM) e no modelo de três fatores de Fama-French, com estimativas mais eficientes na ausência de outliers, e alfas consistentes quando os outliers estão presentes.The purpose of this work is to present the Weighted Forward Search (FSW) method for the detection of outliers in asset pricing data. This new estimator, which is based on an algorithm that downweights the most anomalous observations of the dataset, is tested using both simulated and empirical asset pricing data. The impact of outliers on the estimation of asset pricing models is assessed under different scenarios, and the results are evaluated with associated statistical tests based on this new approach. Our proposal generates an alternative procedure for robust estimation of portfolio betas, allowing for the comparison between concurrent asset pricing models. The algorithm, which is both efficient and robust to outliers, is used to provide robust estimates of the models’ parameters in a comparison with traditional econometric estimation methods usually used in the literature. In particular, the precision of the alphas is highly increased when the Forward Search (FS) method is used. We use Monte Carlo simulations, and also the well-known dataset of equity factor returns provided by Prof. Kenneth French, consisting of the 25 Fama-French portfolios on the United States of America equity market using single and three-factor models, on monthly and annual basis. Our results indicate that the marginal rejection of the Fama-French three-factor model is influenced by the presence of outliers in the portfolios, when using monthly returns. In annual data, the use of robust methods increases the rejection level of null alphas in the Capital Asset Pricing Model (CAPM) and the Fama-French three-factor model, with more efficient estimates in the absence of outliers and consistent alphas when outliers are present

Simulated microgravity affects directional growth of pollen tubes in candidate space crops

BackgroundLong-term space missions will necessarily require producing viable seeds to be used for plant cultivation over time under altered gravity conditions. Pollen is known to play a key role in determining seed and fruit production over seed-to-seed cycles, but very few studies have evaluated pollen functionality under altered gravity.MethodsWe performed ground-based experiments to test how simulated microgravity can affect the directional growth of pollen tubes as a potential bottleneck in seed and fruit sets. The effect of clinorotation was assessed in the pollen of Solanum lycopersicum L. cv. ‘Micro-Tom’ and Brassica rapa L. var. silvestris, both eligible for cultivation in space. Pollen tube length and tortuosity were compared under 1g and simulated microgravity with a uniaxial clinostat.ResultsThe main results highlighted that simulated microgravity significantly increased pollen tube length and tortuosity compared to 1g conditions. Further, clinorotation prompted a differential effect on pollen germination between S. lycopersicum and B. rapa. A more in-depth analysis evaluating the effect of gravity on the directional growth of pollen tubes excluded gravitropic responses as responsible for the tube tip position reached after germination.DiscussionThis research provides new insights into how altered gravity can interfere with plant reproduction and, in particular, microgametophyte functionality. Our findings represent a basis for further studies aimed at understanding the effect of real microgravity on plant reproduction and developing countermeasures to ensure seed-to-seed cultivation in long-term space missions and achieve self-sufficiency in food supplies from Earth

COVID-19 and coagulative axis: review of emerging aspects in a novel disease

Latest evidences from literature suggest that SARS-CoV-2 disease 2019 (COVID-19) is commonly complicated with coagulopathy and that disseminated intravascular coagulation is present in the majority of deceased patients. Particularly, conventional coagulation parameters appear to be significantly altered in patients with poor prognosis. A wide-ranging cross- talk between coagulative haemostasis and inflammation, as well as the activation of coagulation cascade during viral infections, are well established. Another important evidence which may explain coagulation disorders in COVID-19 is the increase of thrombus formation under conditions of hypoxia. Despite the exact pathophysiological mechanism of coronavirus-induced thromboembolism needs to be further investigated, this finding suggests that it is good practice to assess the risk of thrombosis in COVID-19 patients to improvethe clinical management in terms of anticoagulation therapy. Anticoagulants, mainly low-molecular-weight heparin (LMWH), should be tailored in patients meeting sepsis induced coagulopathy (SIC) criteria or with markedly elevated D-dimer. In this context, further studies are needed to optimise the decision making in therapeutic approach

Elderly with COPD: comoborbitidies and systemic consequences

Chronic obstructive pulmonary disease (COPD) represents a comple respiratory disorder characterized by persistent respiratory symptoms due to chronic airflow limitation caused by exposure to noxious particles/gases with an increased inflammatory response of the airways. COPD is common in older people, with an estimated prevalence of 10% in the US population aged > 75 years and is often accompanied by other concomitant chronic conditions that negatively impact prognosis and health status. The aim of this paper is to highlight the relationship between COPD and other comorbidities in elderly population. We focus our attention on the relationship existing between COPD and cardiovascular diseases, lung cancer, obstructive sleep apnoea syndrome, malnutrition/sarcopenia and osteoporosis with particular attention to adipokines, considering that adipose tissue plays a relevant role in the cross-talk between organs

Root Tropisms: New Insights Leading the Growth Direction of the Hidden Half

Tropisms are essential responses of plants, orienting growth according to a wide range of stimuli. Recently, considerable attention has been paid to root tropisms, not only to improve cultivation systems, such as those developed for plant-based life support systems for future space programs, but also to increase the efficiency of root apparatus in water and nutrient uptake in crops on Earth. To date, the Cholodny–Went theory of differential auxin distribution remains the principal tropistic mechanism, but recent findings suggest that it is not generally applicable to all root tropisms, and new molecular pathways are under discussion. Therefore, an in-depth understanding of the mechanisms and functions underlying root tropisms is needed. Contributions to this special issue aimed to embrace reviews and research articles that deepen molecular, physiological, and anatomical processes orchestrating root tropisms from perception of the stimulus to bending. The new insights will help in elucidating plant–environment interactions, providing potential applications to improve plant growth on Earth and in space where microgravity diminishes or nullifies the gravitropism dominance

Identifying outliers in asset pricing data with a new weighted forward search estimator

In this paper the impact of outliers on the estimation of asset pricing models and in associated statistical tests is assessed. A new estimator based on the Forward Search (Atkinson and Riani, 2000) \u2013 which is both efficient and robust to outliers \u2013 is applied to the 25 Fama-French portfolios (Fama and French, 1993) in the time-series framework of asset pricing analysis. The new estimator is used to identify outliers and to provide robust estimates of the models\u2019 parameters. Our results indicate that the use of robust methods increases the rejection level of the CAPM and the Fama-French three factor model. It is also shown that the outliers identified are linked to relevant economic events such as stock market crashes and bubbles in asset prices

Subsequent inclusion/exclusion criteria to select the best species for an experiment performed on the ISS in a refurbished hardware

The interest in re-using flown hardware for new and different space biology experiments is increasing. To match the constraints of the flown hardware with the requirements of the new biological system, innovative methodological approaches are necessary. MULTITROP was a successful plant biology experiment that was performed on the ISS to investigate multiple-tropism interactions during the early stage of seedling growth. We used the hardware designed and flown for the IFOAM experiment in 2009. The main challenge was to implement seeds of a crop species in a growth chamber conceived for yeast culture and to grow the seedlings in microgravity condition but activating seed germination on ground before the launch. Our approach was to adapt the biological system to the hardware constraints and also to the experiment timing and the environmental factors expected during the prelaunch, launch and flight operations. We looked for an objective and repeatable method to effectively select the best suited species. Innovatively, we applied the method of inclusion/exclusion criteria to adapt a new biological system to a reused hardware. The list and the consecutive order of the specific inclusive/exclusive criteria turned out to be a valid support to guide the science team in objectively choosing the most suitable species for the experiment. Among the 50 initial food species, the carrot seeds resulted as the best in satisfying all technical requirements and post-flight data confirmed the expectations