58 research outputs found

    Water Potential Gradients between Old and Developing Leaves in Lithops (Aizoaceae).

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    Lithops plants consist of a pair of opposite succulent leaves inserted on a short stem. The apical meristem produces a new pair of leaves within the old one every growing season, recycling water from the old leaves. Since there are no data on water relations between the two pairs of leaves, we measured leaf water potential at different stages of development with a pressure chamber. Osmotic potential of cell sap was measured with a cryoscopic osmometer and turgor pressure was calculated indirectly. Leaf water potentials were never very low even though plants were not irrigated. In old leaves water potential ranged between -0.5 and -0.28 MPa. In young leaves water potential increased with size from -1.05 to -0.5 MPa and was always lower than in the corresponding old leaves. The water potential gradient between old and new leaves was steeper in the early stages of development (0.6 MPa) and gradually decreased (0.15 MPa) when young leaves had almost completed their expansion. Our data show that in Lithops water movement from old to young leaves occurs according to a water potential gradient. The maintenance of this gradient may be ascribed to differences in turgor pressure, due to the more elastic and plastic walls of cells of young leaves. The possibility to perform a complete life cycle without external water supply is an extreme adaptation to the arid environment where Lithops grows

    Is in vitro micrografting a possible valid alternative to traditional micropropagation in Cactaceae? Pelecyphora aselliformis as a case study

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    Several taxa of Cactaceae are endangered by overcollection for commercial purposes, and most of the family is included in the Convention on International Trade in Endangered Species of Fauna and Flora (CITES). Micropropagation may play a key role to keep the pressure off wild populations and contribute to ex situ conservation of endangered taxa. One of the limits of micropropagation is the species-specific requirement of plant regulators for each taxon and sometimes even for different genotypes. With the micrografting technique the rootstock directly provides the scion with the necessary hormonal requirements. In this paper we present data on in vitro grafting of Pelecyphora aselliformis Ehrenberg, an Appendix I CITES listed species critically endangered and sought after by the horticultural trade, on micropropagated Opuntia ficus-indica Miller. Apical and sub-apical scions of P. aselliformis were used to perform micrografting with a successful rate of 97 and 81 % respectively. Survival rate after ex vivo transfer was 85 %. We hypothesize that this method could be applied to other endangered, slow growing taxa of Cactaceae thus contributing to the conservation of this endangered family.Several taxa of Cactaceae are endangered by overcollection for commercial purposes, and most of the family is included in the Convention on International Trade in Endangered Species of Fauna and Flora (CITES). Micropropagation may play a key role to keep the pressure off wild populations and contribute to ex situ conservation of endangered taxa. One of the limits of micropropagation is the species-specific requirement of plant regulators for each taxon and sometimes even for different genotypes. With the micrografting technique the rootstock directly provides the scion with the necessary hormonal requirements. In this paper we present data on in vitro grafting of Pelecyphora aselliformis Ehrenberg, an Appendix I CITES listed species critically endangered and sought after by the horticultural trade, on micropropagated Opuntia ficus-indica Miller. Apical and sub-apical scions of P. aselliformis were used to perform micrografting with a successful rate of 97 and 81 % respectively. Survival rate after ex vivo transfer was 85 %. We hypothesize that this method could be applied to other endangered, slow growing taxa of Cactaceae thus contributing to the conservation of this endangered family

    Recovery from water stress in laurel plants: influence of short term potassium fertilization

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    Plant xylem hydraulic conductance varies with changes in sap solute concentrations, particularly potassium, a phenomenon known as 'ionic effect'. In well-watered Laurus nobilis plants, short term potassium fertilization increased xylem sap potassium concentration, resulting in an increase in plant hydraulic conductance (Kplant), leaf-specific conductivity of the shoot (kshoot) and transpiration rate (Eplant). The ionic effect is enhanced in embolized stems, where it can compensate the cavitation-induced loss of hydraulic conductance. The aim of this work was to test if water-stressed potassium-starved laurel plants could recover earlier from stress when irrigated with a potassium solution instead of water. Two-year-old potted laurel seedlings, grown under potassium-starved conditions, were subjected to water stress by suspending irrigation until leaf conductance to water vapor (gL) dropped to less than 50% of its initial value and leaf water potential (YL) reached turgor loss point (YTLP). Plants were then irrigated either with water or 25 mM KCl and measurements were taken at 3, 6 or 24 hours after irrigation. No significant differences were found between the two groups of plants in terms of YL, gL, Eplant, Kplant or kshoot. Analysis of xylem sap potassium concentration showed there were no significant differences between treatments, and potassium levels were similar to those of potassium-starved well-watered plants. In conclusion, potassium uptake or release to xylem appeared to be impaired at least up to 24 hours after relief from water stress, so fertilization after the onset of stress did not result in any short term advantage for recovery from drought stress

    Leaf water relation traits in typical Sicilian varieties of Vitis vinifera L.

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    In Italy, grapevines are extensively cultivated, with Sicily representing one of the most significant wine regions. The high number of autochthonous grapevine varieties represents an important source of genetic diversity, and the many Sicilian varieties have anatomical and physiological traits that allow them to resist to different levels of drought stress. We investigated the water relation parameters of four cultivars of Vitis vinifera L. (Catarratto, Corinto, Nero d'Avola and Zibibbo) and characterized their leaf hydraulics. Measurements were conducted during summer on plants growing in the experimental field of the IBBR-CNR near Palermo. Daily patterns of leaf water potential (Yleaf) and stomatal conductance (gs) were measured in the field. Pressure-volume curves were constructed by the bench dehydration method to obtain leaf water potential at turgor loss point (Ytlp), osmotic potential at full rehydration (p0) and bulk modulus of elasticity (Δmax). Leaf samples were collected to determine vein density using ImageJ. Major vein density was measured on digitally scanned leaves, while minor vein density was measured on photomicrographs of cleared and stained leaf portions

    Experimental testing of two novel stress sensors for SHM of masonry structures

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    The paper presents an experimental study on the performance of two types of stress sensor for their possible use in structural health monitoring (SHM) of masonry constructions. Ceramic piezoelectric sensors and capacitive sensors were installed in mortar bed-joints of two series of masonry specimens made of calcarenite stones and clay bricks. The specimens were tested under uniaxial compression, assessing the effectiveness of the sensors in recording the stress state variation in terms of vertical stresses within different types of masonry. Experimental results show that, although both the ceramic and capacitive sensors were initially designed to be embedded in concrete elements, their application in mortar joints ensures a good agreement with records by standard measurement devices. Results also demonstrate the possibility to extend the application of these devices to existing masonry structures, where SHM becomes a challenging issu

    A meta-learning algorithm for respiratory flow prediction from FBG-based wearables in unrestrained conditions

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    The continuous monitoring of an individual's breathing can be an instrument for the assessment and enhancement of human wellness. Specific respiratory features are unique markers of the deterioration of a health condition, the onset of a disease, fatigue and stressful circumstances. The early and reliable prediction of high-risk situations can result in the implementation of appropriate intervention strategies that might be lifesaving. Hence, smart wearables for the monitoring of continuous breathing have recently been attracting the interest of many researchers and companies. However, most of the existing approaches do not provide comprehensive respiratory information. For this reason, a meta-learning algorithm based on LSTM neural networks for inferring the respiratory flow from a wearable system embedding FBG sensors and inertial units is herein proposed. Different conventional machine learning approaches were implemented as well to ultimately compare the results. The meta-learning algorithm turned out to be the most accurate in predicting respiratory flow when new subjects are considered. Furthermore, the LSTM model memory capability has been proven to be advantageous for capturing relevant aspects of the breathing pattern. The algorithms were tested under different conditions, both static and dynamic, and with more unobtrusive device configurations. The meta-learning results demonstrated that a short one-time calibration may provide subject-specific models which predict the respiratory flow with high accuracy, even when the number of sensors is reduced. Flow RMS errors on the test set ranged from 22.03 L/min, when the minimum number of sensors was considered, to 9.97 L/min for the complete setting (target flow range: 69.231 Â± 21.477 L/min). The correlation coefficient r between the target and the predicted flow changed accordingly, being higher (r = 0.9) for the most comprehensive and heterogeneous wearable device configuration. Similar results were achieved even with simpler settings which included the thoracic sensors (r ranging from 0.84 to 0.88; test flow RMSE = 10.99 L/min, when exclusively using the thoracic FBGs). The further estimation of respiratory parameters, i.e., rate and volume, with low errors across different breathing behaviors and postures proved the potential of such approach. These findings lay the foundation for the implementation of reliable custom solutions and more sophisticated artificial intelligence-based algorithms for daily life health-related applications

    Mild cognitive impairment, from theory to practical intervention: “Camminando e leggendo 
 ricordo” (Walking and reading... I remember), an action plan. The Treviso Dementia (TREDEM) Registry

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    Dementia is one of the most disabling health conditions in older people. Increasing attention is paid to the preclinical phase of dementia and to the prevention programs to reduce the number of patients in the future. Aims of the current study are: a) to elucidate the relationships between the concepts of Mild Cognitive Impairment (MCI), and Cognitive Frailty (CF), in the light of the more recent literature and b) to present a model, called "Camminando e leggendo
ricordo" (CLR), as a practical experience of secondary prevention aimed at MCI older people.The CLR model is composed of a program of physical and reading activities in group to promote healthy lifestyles. Here we present a protocol to evaluate the effectiveness of our intervention model. A multidimensional geriatric assessment will be carried out. A questionnaire for the detection of frailty, disability and for the adherence to the Mediterranean diet will be administered. The Psychological General Well-Being Index (PGWBI) will be used to assess the quality of life.CLR is an intervention model for secondary prevention in MCI subjects. It is the description of a practical proposal aimed at improving lifestyles and reducing the risk of dementia.

    Fluid therapy in neurointensive care patients: ESICM consensus and clinical practice recommendations.

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    OBJECTIVE: To report the ESICM consensus and clinical practice recommendations on fluid therapy in neurointensive care patients. DESIGN: A consensus committee comprising 22 international experts met in October 2016 during ESICM LIVES2016. Teleconferences and electronic-based discussions between the members of the committee subsequently served to discuss and develop the consensus process. METHODS: Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles generated. The consensus focused on three main topics: (1) general fluid resuscitation and maintenance in neurointensive care patients, (2) hyperosmolar fluids for intracranial pressure control, (3) fluid management in delayed cerebral ischemia after subarachnoid haemorrhage. After an extensive literature search, the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system were applied to assess the quality of evidence (from high to very low), to formulate treatment recommendations as strong or weak, and to issue best practice statements when applicable. A modified Delphi process based on the integration of evidence provided by the literature and expert opinions-using a sequential approach to avoid biases and misinterpretations-was used to generate the final consensus statement. RESULTS: The final consensus comprises a total of 32 statements, including 13 strong recommendations and 17 weak recommendations. No recommendations were provided for two statements. CONCLUSIONS: We present a consensus statement and clinical practice recommendations on fluid therapy for neurointensive care patients

    Palynological and chemical volatile components of tipically autumnal honeys of the western Mediterranean

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    [EN] Twenty-five samples of autumnal honeys from the western Mediterranean (Mallorca and Eivissa, Balearic Islands) were examined for pollen content (qualitative and quantitative melissopalynological analysis), moisture, electrical conductivity, colour, sensorial qualities and volatile components. Quantitative analysis showed that the honey contained Maurizio's Class II: 64%, Class III: 28%, Class IV: 4% and Class V: 4%. Fifty-four pollen types, with an average number of 16.68 per sample, were identified, belonging to 29 botanical families. Only two taxa (Ceratonia siliqua and Erica multiflora) were found in all samples. Seventeen samples were unifloral (68%) - ten (40%) of C. siliqua, six (24%) of E. multiflora and one (4%) of Hedera helix. All honeys have a low honeydew index (<?0.09%), while the values for electrical conductivity and water content were high. The major honey volatile components are: cis- and trans-linalool oxides (64.2%) and hotrienol (10.4%) for the carob (C. siliqua) and trans-linalool oxide (13.4%), p-menthane-1,8-diol (11.1%), safranal (9.7%), limonene (5,4%), -pinene (3.7%) and oxoisophorone (3.4%) for the winter heather (E. multiflora).The authors would like to extend their gratitude to the Mallorca Rural 'Leader plus' programme and the beekeepers of Mallorca and Eivissa for their support and friendly collaboration. The authors also thank an anonymous reviewer for useful comments and suggestions on an earlier version of the manuscript.Boi, M.; Llorens Molina, JA.; CortĂ©s, L.; LladĂł, G.; Llorens, L. (2013). Palynological and chemical volatile components of tipically autumnal honeys of the western Mediterranean. Grana. 52(2):93-105. doi:10.1080/00173134.2012.744774S93105522Andrade, P. B., Amaral, M. T., Isabel, P., Carvalho, J. C. M. F., Seabra, R. M., & Proença da Cunha, A. (1999). 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