Scaling of leaf area with biomass in trees reconsidered: constant metabolically active sapwood volume per unit leaf area with height growth.

Hypoallometric (slope<1) scaling between metabolic rate and body mass is often regarded as near-universal across organisms. However, there are compelling reasons to question hypoallometric scaling in woody plants, where metabolic rate is directly proportional to leaf area. This leaf area must provide carbon to the volume of the metabolically active sapwood (VMASW). Within populations of a species, variants in which VMASW increases per unit leaf area with height growth (e.g. ⅔ or ¾ scaling) would have proportionally less carbon for growth and reproduction as they grow taller. Therefore, selection should favor individuals in which, as they grow taller, leaf area scales isometrically with shoot VMASW (slope=1). Using tetrazolium staining, we measured total VMASW and total leaf area (LAtot) across 22 individuals of Ricinus communis and confirmed that leaf area scales isometrically with VMASW, and that VMASW is much smaller than total sapwood volume. With the potential of the LAtot-VMASW relationship to shape factors as diverse as the crown area-stem diameter relationship, conduit diameter scaling, reproductive output, and drought-induced mortality, our work indicates that the notion that sapwood increases per unit leaf area with height growth requires revision.

The Widened Pipe Model of plant hydraulic evolution.

Shaping global water and carbon cycles, plants lift water from roots to leaves through xylem conduits. The importance of xylem water conduction makes it crucial to understand how natural selection deploys conduit diameters within and across plants. Wider conduits transport more water but are likely more vulnerable to conduction-blocking gas embolisms and cost more for a plant to build, a tension necessarily shaping xylem conduit diameters along plant stems. We build on this expectation to present the Widened Pipe Model (WPM) of plant hydraulic evolution, testing it against a global dataset. The WPM predicts that xylem conduits should be narrowest at the stem tips, widening quickly before plateauing toward the stem base. This universal profile emerges from Pareto modeling of a trade-off between just two competing vectors of natural selection: one favoring rapid widening of conduits tip to base, minimizing hydraulic resistance, and another favoring slow widening of conduits, minimizing carbon cost and embolism risk. Our data spanning terrestrial plant orders, life forms, habitats, and sizes conform closely to WPM predictions. The WPM highlights carbon economy as a powerful vector of natural selection shaping plant function. It further implies that factors that cause resistance in plant conductive systems, such as conduit pit membrane resistance, should scale in exact harmony with tip-to-base conduit widening. Furthermore, the WPM implies that alterations in the environments of individual plants should lead to changes in plant height, for example, shedding terminal branches and resprouting at lower height under drier climates, thus achieving narrower and potentially more embolism-resistant conduits.

The vessel wall thickness-vessel diameter relationship across woody angiosperms.

PREMISE: Comparative anatomy is necessary to identify the extremes of combinations of functionally relevant structural traits, to ensure that physiological data cover xylem anatomical diversity adequately, and thus achieve a global understanding of xylem structure-function relations. A key trait relationship is that between xylem vessel diameter and wall thickness of both the single vessel and the double vessel+adjacent imperforate tracheary element (ITE). METHODS: We compiled a comparative data set with 1093 samples, 858 species, 350 genera, 86 families, and 33 orders. We used broken linear regression and an algorithm to explore changes in parameter values from linear regressions using subsets of the data set to identify a threshold, at 90-µm vessel diameter, in the wall thickness-diameter relationship. RESULTS: Below 90 µm diameter for vessels, virtually any wall thickness could be associated with virtually any diameter. Below this threshold, selection is free to favor a very wide array of combinations, such as very thick walls and narrow vessels in ITE-free herbs, or very thin-walled, wide vessels in evergreen dryland pioneers. Above 90 µm, there was a moderate positive relationship. CONCLUSIONS: Our analysis shows that the space of vessel wall thickness-diameter combinations is very wide, with selection apparently eliminating individuals with vessel walls "too thin" for their diameter. Most importantly, our survey revealed poorly studied plant hydraulic syndromes (functionally significant trait combinations). These data suggest that the full span of trait combinations, and thus the minimal set of hydraulic syndromes requiring study to span woody plant functional diversity adequately, remains to be documented.

Plant height and hydraulic vulnerability to drought and cold.

Understanding how plants survive drought and cold is increasingly important as plants worldwide experience dieback with drought in moist places and grow taller with warming in cold ones. Crucial in plant climate adaptation are the diameters of water-transporting conduits. Sampling 537 species across climate zones dominated by angiosperms, we find that plant size is unambiguously the main driver of conduit diameter variation. And because taller plants have wider conduits, and wider conduits within species are more vulnerable to conduction-blocking embolisms, taller conspecifics should be more vulnerable than shorter ones, a prediction we confirm with a plantation experiment. As a result, maximum plant size should be short under drought and cold, which cause embolism, or increase if these pressures relax. That conduit diameter and embolism vulnerability are inseparably related to plant size helps explain why factors that interact with conduit diameter, such as drought or warming, are altering plant heights worldwide.

Hydraulic traits vary as the result of tip-to-base conduit widening in vascular plants.

Plant hydraulic traits are essential metrics for characterizing variation in plant function, but they vary markedly with plant size and position in a plant. We explore the potential effect of conduit widening on variation in hydraulic traits along the stem. We examined three species that differ in conduit diameter at the stem base for a given height (Moringa oleifera, Casimiroa edulis, and Pinus ayacahuite). We made anatomical and hydraulic measurements at different distances from the stem tip, constructed vulnerability curves, and examined the safety-efficiency trade-off with height-standardized data. Our results showed that segment-specific hydraulic resistance varied predictably along the stem, paralleling changes in mean conduit diameter and total number of conduits. The Huber value and leaf specific conductivity also varied depending on the sampling point. Vulnerability curves were markedly less noisy with height standardization, making the vulnerability-efficiency trade-off clearer. Because conduits widen predictably along the stem, taking height and distance from the tip into account provides a way of enhancing comparability and interpretation of hydraulic traits. Our results suggest the need for rethinking hydraulic sampling for comparing plant functional differences and strategies across individuals.

Constant theoretical conductance via changes in vessel diameter and number with height growth in Moringa oleifera.

As trees grow taller, hydraulic resistance can be expected to increase, causing photosynthetic productivity to decline. Yet leaves maintain productivity over vast height increases; this maintenance of productivity suggests that leaf-specific conductance remains constant as trees grow taller. Here we test the assumption of constant leaf-specific conductance with height growth and document the stem xylem anatomical adjustments involved. We measured the scaling of total leaf area, mean vessel diameter at terminal twigs and at the stem base, and total vessel number in 139 individuals of Moringa oleifera of different heights, and estimated a whole-plant conductance index from these measurements. Whole-plant conductance and total leaf area scaled at the same rate with height. Congruently, whole-plant conductance and total leaf area scaled isometrically. Constant conductance is made possible by intricate adjustments in anatomy, with conduit diameters in terminal twigs becoming wider, lowering per-vessel resistance, with a concomitant decrease in vessel number per unit leaf area with height growth. Selection maintaining constant conductance per unit leaf area with height growth (or at least minimizing drops in conductance) is likely a potent selective pressure shaping plant hydraulics, and crucially involved in the maintenance of photosynthetic productivity per leaf area across the terrestrial landscape.

Effectiveness of palivizumab in preventing respiratory syncytial virus infection in high-risk children.

To date, there is no consensus regarding palivizumab prophylaxis for respiratory syncytial virus infection. The purpose of this study is to assess the effectiveness of palivizumab prophylaxis to prevent respiratory syncytial virus-related infection consultations and hospitalizations in high-risk children <2 y. We studied children <2 y of age with risk factors who had indication of palivizumab prophylaxis over eight epidemic seasons (2011-2012 to 2018-2019) in Navarra, Spain. Children positives for respiratory syncytial virus by reverse-transcription polymerase chain reaction were compared to negative testers. Palivizumab was indicated in 1,214 children <2 y of age with risk factors during 2011-2012 to 2018-2019 seasons. A total of 142 high-risk children tested for respiratory syncytial virus were included in the study. From the 35 respiratory syncytial virus-positive confirmed cases, 20 (57%) had received palivizumab versus 82 (77%) from the 107 negative controls. The effectiveness of prophylactic palivizumab was 70% (95% CI, 19%-90%) in preventing confirmed clinical infection and 82% (95% CI, 29%-96%) in preventing hospitalized cases. Our results show that palivizumab is notably effective for preventing laboratory-confirmed cases of respiratory syncytial virus and hospitalization in high-risk children <2 y of age. For children who have received palivizumab, the risk of getting sick remains high; thus, other preventive measures are necessary.

[The effect of a falls prevention program in elderly people in primary health care. What does Tai Chi practice provide?] / Efecto de un programa de prevención de caídas en personas mayores en atención primaria. ¿Qué aporta la práctica de Tai Chi?

OBJECTIVE: Falls in the elderly are a major health problem. There are multiple experiences of intervention in primary care. Aim: To evaluate the impact of a multifactorial intervention in the prevention of falls in elderly people. To compare the differential effect of the practice of Tai Chi. METHODS: Non-randomized before-after quasi-experimental design in an urban health center between the years 2014-2017. The study population was those over 65 years old with a high risk of falls. The intervention consisted of an individual assessment of risk factors: sensory problems, balance, orthostatic hypotension, treatments (psychotropic drugs, hypotensive drugs), barriers, technical aids. It was intervened in its correction. Tai Chi group participation is proposed. The dependent variables (baseline and year measurements) were Barthel, Unipodal Station Test (TEU), number of falls per year, Anxiety/Depression Goldberg Scale (EADG), number of medical consultations per year, walking aids, Daily Dose Defined of analgesics (DDD)/ year. The before-after analysis was performed using the Chi2 and T Student statistics for paired samples. RESULTS: A total of 93 patients participated with an average age of 76+06,65, 84.9% women. Falls/year baseline 1.65 + 0.24; no significant differences between groups with or without Tai Chi in any baseline variable. At one year, average reduction of falls/year 0.53 (IC95% 0,07-0,99) (p=0.023), EADG anxiety 1.4±0.33 points (p<0.0001), EAGD depression 0.73±0.26 points (p=0.007). 44 patients practiced Tai Chi; finding: reduction of 1.88 (IC95% 0.90-2.80) points (p<0.0001) in EADG anxiety and 0.86 points (IC95% 0.12-1.60) (p=0.024) in EADG depression; 30.9% of patients abandoned technical aids (p<0.0001); 11% started psychotropic drugs. 49 patients did not practice Tai Chi; of them: EADG anxiety reduction of 1,020 points (IC95% 0.07-1.96) (p=0.035); 41.2% of patients initiated psychotropic drugs (p=0.001); none of the patients abandoned technical aids and 14.3% started them (p<0.001). CONCLUSIONS: The intervention reduced the number of falls, anxiety, the use of psychotropic drugs, depression, and the use of walking aids, with differential benefit of Tai Chi in these last three aspects.

OBJETIVO: Las caídas en las personas mayores son un problema de salud de primer orden. Existen múltiples experiencias de intervención en atención primaria. El objetivo de este trabajo fue evaluar el impacto de una intervención multifactorial en prevención de caídas en personas mayores y comparar el efecto diferencial de practicar Tai Chi. METODOS: Diseño cuasiexperimental antes-después no aleatorizado en un centro de salud urbano entre los años 2014-2017. La población de estudio fueron los mayores de 65 años con alto riesgo de caídas. La intervención consistió en una valoración individual de factores de riesgo: problemas sensoriales, equilibrio, hipotensión ortostática, tratamientos (psicofármacos, hipotensores), barreras arquitectónicas, ayudas técnicas. Se intervino en su corrección. Se propone la participación en grupo de Tai Chi. Las variables dependientes (mediciones basal y al año) fueron: Índice de Barthel, Test Estación Unipodal (TEU), número de caídas/año, Escala Ansiedad/Depresión de Goldberg (EADG), número de consultas médicas/año, uso de ayudas para la marcha, Dosis Diaria Definida(DDD) analgésicos/año. Se realizó el análisis antes-después utilizando Chi2 y T Student para muestras apareadas. RESULTADOS: Participaron un total de 93 pacientes, con una edad media de 76±6,65 años y un 84,90% mujeres. Número de Caídas/año basal 1,65±0,24; sin diferencias significativas entre grupos con/sin Tai Chi en ninguna variable inicial. Al año, reducción media de caídas/año a 0,53 (IC95% 0,07-0,99) (p=0.023), EADG ansiedad 1,40±0,33 puntos(p<0,0001), EADG depresión 0,73±0,26 puntos (p=0.007). Practicaron Tai Chi 44 pacientes, encontrándose: reducción de 1,88 (IC95% 0,90-2,80) puntos (p<0.0001) en EADG ansiedad y 0,86 puntos (IC95% 0,12-1,60) (p=0,024) en EADG depresión; 30,90% de pacientes abandonaron ayudas técnicas (p<0.0001); iniciaron psicofármacos 11%. No practicaron Tai Chi 49 pacientes, en ellos se redujo 1,02 puntos la EADG ansiedad (IC95% 0,07-1,96) (p=0,035); 41,20% de pacientes iniciaron psicofármacos (p=0,001); ningún paciente abandonó ayudas técnicas y 14,30% las iniciaron (p<0,001). CONCLUSIONES: La intervención redujo las caídas, la ansiedad, el uso de los psicofármacos, la depresión, y el uso de ayudas para la marcha, con beneficio diferencial del Tai Chi en estos tres últimos aspectos.

Fomento de la dieta mediterránea mediante la práctica de la cocina tradicional / Promotion of the Mediterranean diet based on the practice of traditional cuisine

Los hábitos de vida son un importante determinante de la salud, encontrándose entre ellos la alimentación saludable. Es primordial centrar nuestros esfuerzos en promocionar la dieta mediterránea. OBJETIVOS: fomentar el conocimiento y la práctica de la cocina tradicional basada en la dieta mediterránea en la población adscrita a un centro de salud. MÉTODOS: estrategia de participación comunitaria basada en el trabajo coordinado de asociaciones vecinales, ciudadanas y culturales de la zona, para promocionar un envejecimiento saludable. Intervención comunitaria basada en el fortalecimiento de la comunidad mediante distintas actividades compartidas. RESULTADOS: Libro de recetas: recetas tradicionales aportadas por personas de la zona. Dos ediciones (2014 y 2018) con 23 y 25 recetas. Receta del mes: difundida en consultas del centro de salud, los expositores y las páginas web de asociaciones de la zona. Talleres de cocina (2015-2019): elaboración grupal y comida colectiva, recetas de cocina popular. Se realizan tres sesiones prácticas, con 15 personas. 1) Cocinamos (grupos de 5 personas). 2) Comemos juntos, siguiendo la «forma de comer» mediterránea: encuentro, compañía y disfrute. 3) Puesta en común de la forma de elaboración por la persona responsable del plato. 4) Recogida y limpieza. Sesiones divulgativas: metodología participativa, enfoque práctico. Se han realizado las siguientes sesiones divulgativas: taller de aceites de oliva (2015), taller de quesos (2016), taller de tipos de pan (2017), taller de leches (2018), taller de azúcares (2019) y sesiones sobre alimentación saludable en centros educativos. Desayunos saludables (2016-2019): se han organizado en el centro educativo en el que se realiza el taller de cocina. CONCLUSIONES: el fomento de la dieta mediterránea puede hacerse desde la participación comunitaria con intervenciones colaborativas

Lifestyles are important determinants of health, including healthy diet. This is fundamental to focus our efforts on promoting a Mediterranean diet. OBJECTIVES: To encourage knowledge and practice of traditional cuisine based on a Mediterranean diet in the population assigned to a Health Centre. METHODS: Community participation strategy based on coordination with neighborhood, city and cultural associations in the area to promote healthy ageing. Community intervention based on strengthening the community by shared activities. RESULTS: Recipe book: Traditional recipes provided by local people. There are two editions (2014, 2018) with 23 and 25 recipes, respectively. Recipe of the month: Widespread coverage in health centre, display to the public and area association websites. Cooking workshops: Group cooking and collective meals of popular cuisine recipes, three practice sessions, 15 people. 1) We cook; 3-5 people. 2) We share the meal. Dish tasting according to the Mediterranean style of eating: meeting, company and enjoyment. 3) Sharing the way the dish was cooked by the person responsible for it. 4) Collecting and cleaning. Informative sessions: Participatory methodology, practical approach. Workshops which took place: "Olive oil workshop" (2015). "Cheese workshop" (2016). "Types of bread workshop"(2017). "Milk workshop" (2018). "Sugar workshop" (2019). Sessions about healthy eating in schools. Healthy breakfast (2016-2019): in schools with cooking workshops. CONCLUSIONS: The Mediterranean diet can be promoted from community participation with collaborative interventions

Efecto de un programa de prevención de caídas en personas mayores en atención primaria. ¿Qué aporta la práctica de Tai Chi? / The effect of a falls prevention program in elderly people in primary health care. What does Tai Chi practice provide?

OBJETIVO: Las caídas en las personas mayores son un problema de salud de primer orden. Existen múltiples experiencias de intervención en atención primaria. El objetivo de este trabajo fue evaluar el impacto de una intervención multifactorial en prevención de caídas en personas mayores y comparar el efecto diferencial de practicar Tai Chi. MÉTODOS: Diseño cuasiexperimental antes-después no aleatorizado en un centro de salud urbano entre los años 2014-2017. La población de estudio fueron los mayores de 65 años con alto riesgo de caídas. La intervención consistió en una valoración individual de factores de riesgo: problemas sensoriales, equilibrio, hipotensión ortostática, tratamientos (psicofármacos, hipotensores), barreras arquitectónicas, ayudas técnicas. Se intervino en su corrección. Se propone la participación en grupo de Tai Chi. Las variables dependientes (mediciones basal y al año) fueron: Índice de Barthel, Test Estación Unipodal (TEU), número de caídas/año, Escala Ansiedad/Depresión de Goldberg (EADG), número de consultas médicas/año, uso de ayudas para la marcha, Dosis Diaria Definida(DDD) analgésicos/año. Se realizó el análisis antes-después utilizando Chi2 y T Student para muestras apareadas. RESULTADOS: Participaron un total de 93 pacientes, con una edad media de 76+/-6,65 años y un 84,90% mujeres. Número de Caídas/año basal 1,65+/-0,24; sin diferencias significativas entre grupos con/sin Tai Chi en ninguna variable inicial. Al año, reducción media de caídas/año a 0,53 (IC95% 0,07-0,99) (p=0.023), EADG ansiedad 1,40+/-0,33 puntos(p<0,0001), EADG depresión 0,73+/-0,26 puntos (p=0.007). Practicaron Tai Chi 44 pacientes, encontrándose: reducción de 1,88 (IC95% 0,90-2,80) puntos (p<0.0001) en EADG ansiedad y 0,86 puntos (IC95% 0,12-1,60) (p=0,024) en EADG depresión; 30,90% de pacientes abandonaron ayudas técnicas (p<0.0001); iniciaron psicofármacos 11%. No practicaron Tai Chi 49 pacientes, en ellos se redujo 1,02 puntos la EADG ansiedad (IC95% 0,07-1,96) (p=0,035); 41,20% de pacientes iniciaron psicofármacos (p=0,001); ningún paciente abandonó ayudas técnicas y 14,30% las iniciaron (p<0,001). CONCLUSIONES: La intervención redujo las caídas, la ansiedad, el uso de los psicofármacos, la depresión, y el uso de ayudas para la marcha, con beneficio diferencial del Tai Chi en estos tres últimos aspectos

OBJECTIVE: Falls in the elderly are a major health problem. There are multiple experiences of intervention in primary care. Aim: To evaluate the impact of a multifactorial intervention in the prevention of falls in elderly people. To compare the differential effect of the practice of Tai Chi. METHODS: Non-randomized before-after quasi-experimental design in an urban health center between the years 2014-2017. The study population was those over 65 years old with a high risk of falls. The intervention consisted of an individual assessment of risk factors: sensory problems, balance, orthostatic hypotension, treatments (psychotropic drugs, hypotensive drugs), barriers, technical aids. It was intervened in its correction. Tai Chi group participation is proposed. The dependent variables (baseline and year measurements) were Barthel, Unipodal Station Test (TEU), number of falls per year, Anxiety/Depression Goldberg Scale (EADG), number of medical consultations per year, walking aids, Daily Dose Defined of analgesics (DDD)/ year. The before-after analysis was performed using the Chi2 and T Student statistics for paired samples. RESULTS: A total of 93 patients participated with an average age of 76+06,65, 84.9% women. Falls/year baseline 1.65 + 0.24; no significant differences between groups with or without Tai Chi in any baseline variable. At one year, average reduction of falls/year 0.53 (IC95% 0,07-0,99) (p=0.023), EADG anxiety 1.4+/-0.33 points (p<0.0001), EAGD depression 0.73+/-0.26 points (p=0.007). 44 patients practiced Tai Chi; finding: reduction of 1.88 (IC95% 0.90-2.80) points (p<0.0001) in EADG anxiety and 0.86 points (IC95% 0.12-1.60) (p=0.024) in EADG depression; 30.9% of patients abandoned technical aids (p<0.0001); 11% started psychotropic drugs. 49 patients did not practice Tai Chi; of them: EADG anxiety reduction of 1,020 points (IC95% 0.07-1.96) (p=0.035); 41.2% of patients initiated psychotropic drugs (p=0.001); none of the patients abandoned technical aids and 14.3% started them (p<0.001). CONCLUSIONS: The intervention reduced the number of falls, anxiety, the use of psychotropic drugs, depression, and the use of walking aids, with differential benefit of Tai Chi in these last three aspects