Performance Comparison of Different Flat Plate Solar Collectors by Means of the Entropy Generation Rate Using Computational Fluid Dynamics.

In this work, a numerical analysis of three different flat plate solar collectors was conducted using their entropy generation rates. Specifically, the Computational Fluid Dynamics (CFD) technique was used to compare the detailed performance of conventional and zigzag tube geometries of flat plate solar collectors (FPCs) in terms of their entropy generation rates. The effects of fluid viscosity, heat transfer, and heat loss of the flat plate solar collectors were considered for the local and global entropy generation rate analyses. Variations on the inlet volumetric flow rate of the FPCs from 1.0 to 9.0 L/min were simulated under the average solar radiation for one year in the state of Guanajuato, Mexico. The results illustrate and discuss the temperatures, pressures, and global entropy generation rates for volumetric flow variations. The velocity, temperature, and pressure distributions and the maps of the local entropy generation rates inside the collectors are presented and analyzed for the case with a flow rate of 3.0 L/min. These results demonstrate that the zigzag geometries achieved higher outlet temperatures and greater entropy generation rates than the conventional geometry for all the volumetric flow rates considered.

Prevalence of honeybee viruses in different regions of China and Argentina.

Honeybees are threatened by various pathogens and parasites. More than 18 viruses have been described in honeybees and many of them have been detected in China and Argentina. In China, both Apis cerana and Apis mellifera are raised. In Argentina, beekeepers raise different ecotypes of A. mellifera: European honeybees (in both temperate and subtropical regions) and Africanised honeybees (in subtropical areas only). A thorough study was carried out in both China and Argentina to analyse the current virus presence and distribution in different climatic zones and gather information on different bee species/subspecies. Adult honeybees were collected from apiaries in temperate and subtropical regions of China (including areas with exclusive populations of A. mellifera, areas where A. mellifera and A. cerana co-exist, and areas with exclusive populations of A. cerana) and Argentina. Six viruses, namely, deformed wing virus (DWV), black queen cell virus (BQCV), sacbrood virus (SBV), chronic bee paralysis virus (CBPV), acute bee paralysis virus (ABPV) and Israeli acute paralysis virus (IAPV) were detected in China, both in A. cerana and in A. mellifera, while four viruses (DWV, BQCV, CBPV and ABPV) were present in Argentina. Interestingly, multiple infections were commonly found in China, with up to five different viruses co-circulating in some colonies without apparent abnormalities. In this study, no Chinese samples were positive for slow bee paralysis virus. The most prevalent viruses were BQCV (China) and DWV (Argentina). Kashmir bee virus was absent from samples analysed for both countries.

Les populations d'abeilles mellifères sont menacées par de nombreux agents pathogènes et parasites. Parmi eux, 18 virus ont été décrits, dont plusieurs ont été détectés en Chine et en Argentine. Les espèces d'abeilles mellifères élevées en Chine sont Apis cerana et Apis mellifera. En Argentine, les apiculteurs élèvent plusieurs écotypes d'A. mellifera : le type européen dans les régions tempérées et subtropicales et le type africanisé dans les zones subtropicales. Une étude approfondie a été réalisée en Chine et en Argentine dans le but d'identifier les virus présents, d'analyser leur distribution dans différentes zones climatiques et de réunir des informations sur les différentes espèces et sous-espèces d'abeilles présentes. Des abeilles mellifères adultes ont été collectées dans des ruchers des régions tempérées et subtropicales de Chine (zones peuplées exclusivement d'A. mellifera ou d'A. cerana et zones où A. mellifera et A. cerana coexistent) et d'Argentine (A. mellifera seulement). En Chine, six virus, à savoir le virus des ailes déformées, le virus des cellules royales noires, le virus du couvain sacciforme, le virus de la paralysie chronique de l'abeille, le virus de la paralysie aiguë de l'abeille et le virus israélien de la paralysie aiguë ont été détectés aussi bien chez A. cerana que chez A. mellifera ; en Argentine, quatre virus ont été détectés (virus des ailes déformées, virus des cellules royales noires, virus de la paralysie chronique de l'abeille et virus de la paralysie aiguë de l'abeille). Fait intéressant, les infections multiples étaient fréquentes en Chine, avec parfois jusqu'à cinq virus différents circulant dans certaines colonies sans provoquer de manifestations anormales apparentes. Aucun des échantillons analysés en Chine n'a été trouvé positif pour le virus de la paralysie lente de l'abeille. Les virus les plus fréquents étaient, en Chine, le virus des cellules royales noires et en Argentine, le virus des ailes déformées. Le virus du Cachemire n'a été trouvé dans aucun des échantillons analysés dans les deux pays.

Las abejas melíferas están amenazadas por diversos patógenos y parásitos. Se han descrito más de 18 virus que las afectan, muchos de los cuales se han detectado en China y la Argentina. En China se cultivan tanto Apis cerana como Apis mellifera, mientras que los apicultores argentinos crían diferentes ecotipos de A. mellifera: abejas europeas en las regiones templadas y subtropicales y abejas africanizadas en las zonas subtropicales. Los autores exponen un minucioso estudio realizado a la vez en China y la Argentina con el fin de analizar la actual presencia y distribución de virus en diferentes zonas climáticas y reunir información sobre distintas especies y subespecies de abeja. En primer lugar se recogieron abejas adultas de colmenares situados en regiones templadas y subtropicales de China (algunas donde hay exclusivamente poblaciones de A. mellifera, otras donde coexisten A. mellifera y A. cerana y otras zonas que albergan solo poblaciones de A. cerana) y la Argentina (solamente A. mellifera). En las poblaciones chinas tanto de A. cerana como de A. mellifera se detectaron seis virus: virus de las alas deformes (VAD); virus de las celdas reales negras (VCRN); virus de la cría ensacada (VCE); virus de la parálisis crónica de la abeja (VPCA); virus de la parálisis aguda de la abeja (VPAA); y virus de la variante israelí del virus de la parálisis aguda (VPAI), mientras que en la Argentina se observó la presencia de cuatro virus (VAD, VCRN, VPCA y VPAA). Un dato interesante es que en China se observaron con frecuencia infecciones múltiples, con hasta cinco virus diferentes circulando a la vez en algunas colonias sin que ello diera lugar a anormalidades aparentes. Ninguna de las muestras chinas analizadas en el estudio resultó positiva al virus de la parálisis lenta de la abeja. Los virus más prevalentes fueron el VCRN (China) y el VAD (Argentina). El virus Cachemira de las abejas estaba ausente de las muestras analizadas en ambos países.

Synthesis and antihypertensive effects of new methylthiomorpholinphenol derivatives.

We present in this work the synthesis and cardiovascular effects of new methylthiomorpholine compounds and they were compared with cardiovascular drugs such as captopril, losartan and omapatrilat.

[Renal cell carcinoma presenting as paraneoplastic neurological dysfunction]. / Carcinoma renal que debuta como cuadro neurológico paraneoplásico.

INTRODUCTION: Malignant tumors sometimes initiate as paraneoplastic syndromes even years before the most common symptoms appear. These first manifestations could be the key for the diagnosis of "occult" malignancy. METHODS: We report the case of a 66 year old man with a renal cell carcinoma. The first symptom was a paraneoplastic cerebellar degeneration appeared 6 years before the first urologic manifestations. CONCLUSIONS: A progressive cerebellar syndrome could be the first manifestation of a renal cell carcinoma, even years before the first urologic symptoms. We must suspect an occult neoplasia in such patients.

Synthesis of zeolite membranes on calcium silicate support and their bioactive response.

The synthesis of calcium silicate supported zeolite membrane was carried out by second growth method. The chemical nature of the functionalizing agent on the formation of homogenous zeolite membrane was evaluated. One monomer and two cationic polymers were used: 3-aminopropyltriethoxysilane (APS), polyethylenimine (PEI) and polydiallyldimethylammonium chloride (PDDA). The support was subjected to chemical functionalization and then it was rubbed with zeolite crystals. The W zeolite was used as zeolite seed in two different Si/Al ratios. The functionalized and rubbed supports were submitted to hydrothermal treatment at 150 °C for 48 h. The bioactivity of the homogeneous zeolite membranes was evaluated by the biomimetic method through the membranes soaking in a simulated body fluid (SBF) at 37 °C for 21 days. Two immersion methods were evaluated. The products were characterized by XRD and SEM techniques. The results indicated that the supported functionalization with PDDA and the Si/Al ratio (higher than 1.8) of zeolite enhanced the interaction between the support and the zeolite precursor enhancing the formation of homogeneous zeolite membrane on the surface. The presence of the functional groups of PDDA on the membrane was detected by FTIR. After immersion in SBF, the zeolite membrane was stable and led to the formation of Ca-P layer on its surface. The re-immersion method led to the formation of richer Ca/P layer (1.36). These findings allowed generating a zeolite membrane with combined properties of calcium silicate and the controllable porosity of zeolitic material making it potentially useful for bone regeneration and drug releasing.

Identification of the novel HLA-DRB1 allele, DRB1*14:183, in a Colombian umbilical cord blood bank donor.

HLA-DRB1*14:183 has two nucleotide changes from HLA-DRB1-13:44, D to E and F to Y.

[Citizen perspectives on doctor-prescribed mobile health apps and information and communication technology usage within the Andalusian Healthcare System]. / Visión ciudadana sobre la prescripción de aplicaciones móviles de salud y el uso de tecnologías de la información y la comunicación en el entorno sanitario en Andalucía.

BACKGROUND: As eHealth and mHealth are expanding the concerns about the guarantees that must surround these technologies are increasing. OBJECTIVE: To get to know the opinion of the public on the use and willingness towards communication with health professionals based on new technologies and the use of health apps recommended by those professionals, while identifying the sociodemographic or health differences within the population. MATERIAL AND METHODS: A cross-sectional descriptive study conducted within the Andalusian Barometer about Mobile Health Apps based on telephone surveys (2016) focused on Andalusian citizens over 18 years old. A combined multi-stage random sample was used, proportionally distributed by province, type of home, gender, and age group. Sample size n=1069 individuals. Frequency distribution analysis, contingency tables and chi-squared test were performed using SPSS software. RESULTS: Only 0.7% of citizens, especially those with higher education, have communicated with health professionals using information and communication technologies (ICT). Just over half (55%) of the population who has never communicated in that way would like to do so. Only 1.3% of citizens have ever received any recommendation on health apps given by any health professional, whereas 73.8% would be willing to use a health app recommended by professionals. The population groups that show greater willingness in both issues are those citizens under 44 years old, students or citizens with secondary or higher education, active working population, citizens with good or very good health condition, and those without any chronic disease diagnosed. No significant differences were found as regards the variables of gender, type of home, or living with people with disabilities. CONCLUSIONS: Although there is a high willingness by citizens to use ICT in professional-patient relationships, and to receive recommendations on health apps, they are still not very common. The results obtained are consistent with previous studies, especially regarding the influence of sociodemographic factors in the use and willingness to use of ICTs and recommended apps.

Chronic ethanol intake modifies renin-angiotensin system-regulating aminopeptidase activities in mouse cerebellum.

In developing cerebellum, where critical periods of vulnerability have been established for several basic substances, it has been extensively studied the wide array of abnormalities induced by exposure to ethanol (EtOH). However, little is known about the effects of EtOH consumption on cerebellar functions in adult individuals. Several studies show participation in cognitive activities to be concentrated in the lateral cerebellum (hemispheres), whereas basic motor functions such as balance and coordination are represented in the medial parts of the cerebellum (vermis and paravermis). In addition to the circulating renin angiotensin system (RAS), a local system has been postulated in brain. The effector peptides of the RAS are formed via the activity of several aminopeptidases (AP). The present work analyses the effect of chronic EtOH intake on the RAS-regulating AP activities in the soluble and membrane-bound fractions of two cerebellar locations: the hemispheres and the vermis. We hypothesize that cerebellar RAS is involved in basic motor functions rather than in cognitive activities.

[Clinical validity of the quantitative gait variables in patients with multiple sclerosis. A comparison of the Timed 25-foot Walk Test and the GAITRite ® Electronic Walkway system]. / Validez clinica de las variables cuantitativas de la marcha en pacientes con esclerosis multiple. Comparativa entre el test de los 25 pies y el sistema electronico de marcha GAITRite ®

INTRODUCTION. Multiple sclerosis is an inflammatory and degenerative disease in which gait alteration is one of the first symptoms. Its quantitative evaluation is often made by the Timed 25-foot Walk Test (T25FW), although it's limited to know only the distance, the time employed and number of steps. AIM. To compare the T25FW with the results from the GAITRite ® Electronic Walkway system (GEW), to know if there is some variability between them. PATIENTS AND METHODS. The sample consisted in 85 subjects with multiple sclerosis and able to walking, with or without aids (EDSS: 1.0-6.5). Four walkings were made along the 8 m-length carpet from GEW system, while a different evaluator measured the time employed with a chronometer, and the number of steps in a 25 feet distance marked side by side in the carpet. Velocity was calculated in function of distance and time employed. A mean from the four walkings was made and both of the measures were correlated with SPSS v. 18, considering a results of p < 0.001, statistically significant. RESULTS. Time employed (p = 1.000), velocity (p = 0.9995), cadence (p = 0.3296) and number of steps (p = 1.000) were not statistically different. CONCLUSIONS. GEW system has the same clinical validity in gait evaluation in multiple sclerosis patients than the T25FW.

TITLE: Validez clinica de las variables cuantitativas de la marcha en pacientes con esclerosis multiple. Comparativa entre el test de los 25 pies y el sistema electronico de marcha GAITRite ®Introduccion. La esclerosis multiple es una enfermedad inflamatoria y degenerativa en la que la alteracion de la marcha aparece como uno de los primeros sintomas. Su evaluacion cuantitativa se realiza con frecuencia con el test de los 25 pies ­Timed 25-foot Walk Test (T25FW)­, aunque se limita a conocer la distancia, el tiempo empleado y el numero de pasos. El sistema GAITRite ® Electronic Walkway (GEW) establece tambien estos parametros espaciotemporales, entre otros. Objetivo. Comparar el T25FW con el resultado del sistema GEW para establecer si hay variabilidad entre ambos. Pacientes y metodos. La muestra constaba de 85 sujetos con esclerosis multiple y capaces de deambular, con o sin ayuda (EDSS: 1,0-6,5). Se realizaron cuatro pases por el tapiz electronico de 8 m de longitud, del sistema GEW, que calcula distintos parametros espaciotemporales, a la vez que otro evaluador hacia una medicion con cronometro del tiempo empleado y el numero de pasos dados en una distancia de 25 pies marcada lateralmente en el mismo tapiz. La velocidad se calculo en funcion del tiempo empleado en recorrer los 25 pies. Se hizo una media de los cuatro pases de ambas mediciones y se correlaciono con el programa SPSS v. 18, considerando estadisticamente significativa una p < 0,001. Resultados. Ni el tiempo empleado (p = 1,000), ni la velocidad (p = 0,9995), ni la cadencia (p = 0,3296) ni el numero de pasos (p = 1,000) mostraron diferencias estadisticamente significativas. Conclusiones. El sistema GEW tiene la misma validez clinica en la evaluacion de la marcha en pacientes con esclerosis multiple que el T25FW.

[Skills accreditation as an impetus for continuous professional development]. / Utilidad de la acreditación de competencias profesionales en el desarrollo profesional continuo.

AIM: To analyse the perceived usefulness of continuous professional development (CPD) of the Professional Skills Accreditation Programme of the Andalusian Agency for Healthcare Quality, with 64 Skills Manuals available, one for each professional discipline. MATERIAL AND METHODS: A quantitative and longitudinal study by questionnaire. Field of the study: every professional who has finished their professional skills accreditation process. PERIOD OF STUDY: 2006-2009. A validated questionnaire on the perceived quality of the professional skills accreditation process was distributed online to the targeted population. The questionnaire analysed the professionals' perception on the usefulness of the accreditation process in the "self-learning and reflection of their practice", the "maintenance and improvement of their skills" and the "maintenance and improvement of their results". RESULTS: In 2009, 10,300 professionals were in some phase of the skills accreditation process, 1427 of whom have achieved some accreditation level. A total of 886 completed questionnaires were received (62.0%); the overall rating obtained by the Accreditation Programme was 7.7/10. The rating of the perceived usefulness in continuous professional development was: "self-learning and reflection of their practice": 7.8/10; "maintenance and improvement of their skills": 7.7/10; and "maintenance and improvement of their results": 7.5/10. The average length of their professional practice self-assessment was 168 days. CONCLUSIONS: The Professional Skills Accreditation Programme of the Andalusian Agency for Healthcare Quality was perceived by the professionals as useful for their continuous professional development.

Obesidad pregestacional y riesgo de intolerancia a la glucosa en el embarazo y diabetes gestacional / Pregestational obesity and risk of glucose intolerance in pregnancy and gestational diabetes

ANTECEDENTES: La obesidad en mujeres en edad reproductiva es cada vez más frecuente y complica el embarazo aumentando el riesgo de enfermedades como la diabetes mellitus gestacional (DMG). OBJETIVO: Determinar el riesgo de presentar DMG e intolerancia a la glucosa (ITG) de acuerdo con el índice de masa corporal pregestacional (IMCPG). MÉTODO: Muestra de 489 pacientes, se clasificaron por IMCPG y se les realizó una curva de tolerancia oral a la glucosa (CTOG) de 100 g de 120 minutos. Se definió DMG con dos valores alterados en la CTOG e ITG con un solo valor alterado. Se aplicó prueba de chi cuadrada para determinar diferencia entre grupos y se obtuvo un Odds Ratio (OR), con intervalo de confianza del 95%. RESULTADOS: 9 pacientes con bajo peso, 194 con peso normal, 158 con sobrepeso y 128 con obesidad, edad gestacional promedio 31,3 ± 5,6 semanas. El 13% de las pacientes presentaron DMG, el 10,6% ITG. Las mujeres con sobrepeso presentaron un OR de 3,81 para desarrollar ITG (IC95% 1,62-8,95) y un OR de 3,7 para DMG (IC95% 1,65-8,38), mientas que las pacientes con obesidad pregestacional presentaron un OR de 6,6 para desarrollar ITG (IC95% 2,83-15,66) y un OR de 8,8 para DMG (IC95% 4,05-19,51), comparadas con mujeres con peso pregestacional normal. CONCLUSIÓN: La población mexicana tiene mayor riesgo de DMG que otras poblaciones y mayor prevalencia de sobrepeso y obesidad, por lo que se debe realizar un diagnóstico y tratamiento oportuno de DMG, previniendo complicaciones y diabetes mellitus tipo 2.

BACKGROUND: Obesity in women in reproductive age is becoming more frequent and it self complicates preg-nancy increasing the risk of diseases such as gestational diabetes mellitus (GDM). AIMS: To determine the risk of gestational diabetes mellitus (GDM) and impaired glucose tolerance (IGT) according to the pregestational body mass index (PGBMI). METHODS: Sample of 489 patients, they were classified by PGBMI and underwent an oral glucose tolerance test (OGTT) with 100 g of glucose during 120 minutes. GDM was defined with two altered valúes in the OGTT and IGT with a single altered value. A chi-square test was applied to determine difference between groups, and we obtained an Odds Ratio (OR), with a confidence level of 95%. RESULTS: 9 patients were low weight, 194 normal weight, 158 overweight and 128 obese, average gestational age 31.3 ± 5.6 weeks. 13% of the patients had GDM, 10.6% had IGT. Overweight women had an OR of 3.81 of developing IGT (95% Cl 1.62-8.95) and an OR of 3.7 of developing GDM (95% Cl 1.65-8.38), while women with prepregnancy obesity showed an OR of 6.6 of developing ITG (95% Cl 2.83-15.66) and an OR of 8.8 of developing GDM (95% Cl 4.05-19.51), all compared to women with prepregnancy normal weight. CONCLUSIONS: Mexican population has a higher risk of GDM than other populations and also a higher prevalence of overweight and obesity, so that every pregnant woman should be screening for GDM, has a diagnosis and receive treatment, preventing complications and Type 2 Diabetes.

[Chronic cardiac actinomycosis. Case report and review of the literature]. / Actinomicosis cardíaca crónica. Informe de un caso y revisión de la literatura.

We report the case of a young man in whom a right paracardiac mass was resected. The histopathologic study was compatible with actinomycosis. He developed severe cardiac failure, pulmonary edema and pericardial effusion. He was treated with penicillin, during 12 months. He did well afterwards, however, the echocardiographic follow-up revealed chronic pericardial effusion and thickening and fusion of the pericardium to the epicardial wall.

[Continuous electrocardiographic recording during a first parachute jump]. / Registro electrocardiográfico continuo durante el primer salto en paracaídas.

The behavior of the cardiac rhythm under intense stress was studied with continuous electrocardiographic recording during the first jump with an automatic parachute in 13 members of the Universidad Nacional Autónoma de México sky diving club. There were 12 male (92.3%) and one female (7.68) with an average age of 22.8 years. A complete clinical history, 12 lead electrocardiogram and a treadmill stress test were performed two weeks before jumping. A two-channel Holter recording system was hooked up 30 min. before boarding the airplane and was turned off one hour later. The heart rate values were compared two weeks prior (64.5 beats/min), before (112.8 beats/min), during (170 beats/min) and after the jump (122.8 beats/min). The mean difference between each phase was statistically significant with p less than 0.001 values. The observed cardiac rhythm was sinus tachycardia in each case. In six cases (43.6%) 22 episodes of sudden decrease of the heart rate were seen and there were no major rhythm or conduction disturbances. The urinary catecholamines were similar in nine cases (69.2%) after the jump (x 51.2 micrograms/100 ml) and two weeks later in four control cases (x 10.3 micrograms/100 ml). We concluded there were no significant rhythm disturbances in the presence of an intense but brief stress condition in young healthy people. This study was classified as longitudinally, descriptive, experimental and projective.

[Arteriosclerosis obliterans. Treatment with angiotensin-converting enzyme inhibitors]. / Aterosclerosis obliterante. Tratamiento con inhibidores de la enzima convertidora de angiotensina (ECA).

We compare the effects of two of the main angiotensin convertase enzyme inhibitors, captopril and enalapril, aiming to evaluate their effects in the arterial circulation performance, micro-circulation, and changes in regional blood flow, assuming their property of lowering the angiotensin II blood levels, a very strong peripheral vasoconstrictor. We studied 22 patients: all of them with hypertension and/or skin ulcerations, dropping out those who had venous. They were evaluated periodically, clinically and with photoelectric plethysmography of lower extremities. To interpret the traces we designed an ideogram which gathered the plethysmographic behavior before and after the treatment. Nearly 80% showed considerable improvement in pain, functional capacity and plethysmographic traces patterns. healing of the ulcerations was achieved in all case. We propose some hypothesis to explain the good effect that we have observed.

[Multiple paragangliomas. The problem of its localization. Report of the first case studied with 131I meta-iodobenzylguanidine in our milieu and review of the literature]. / Paragangliomatosis múltiple. El problema de su localización. Informe del primer caso estudiado con [131I] meta-iodobenzilguanidina en nuestro medio y revisión de la literatura.

We report the case of a young woman, with an 8 year history of paroxysmal episodes of dyspnea, palpitations, blurred vision, tremors, precordial oppression and hypertension; the diagnosis of a chromaffin tumor was established, with an increase in serum and urine catecholamines level. She had three surgical interventions and also the following studies: abdominal and pelvic ultrasound, computed tomography, cavography; selective arteriography, and infusion of the meta iodobenzyl-guanidine 131, which localizes tissues hypersecretors rich in catecholamines.

[Pulmonary arterial hypertension of unknown etiology. Study of the cardiopulmonary function]. / Hipertensión arterial pulmonar de etiología desconocida. Estudio de la función cardiopulmonar.

Thirty two cases of pulmonary arterial hypertension of unknown etiology (PAH-UE) were studied. The diagnosis was established by exclusion after the results of hemodinamics studies. Ninety percent of cases had severe PAH (100 mmHg). The end diastolic right ventricular pressure was elevated in 46% of cases. The total pulmonary vascular resistance was increased in the order of the 1700 dinas. seg. cm-5. The cardiac index was 3.3 1/m2 with a right ventricular work index of 3.96 K gm min. The total lung capacity (TLC) was normal, with a vital capacity (VC) of 78% of the predicted value. The residual volume was increased. The mean value of the maximal midexpiratory flow rate (MMFR) was 78%. The A-a gradient of O2 was 30 mmHg, with a venous mixture expressed as a percentage ratio of the cardiac output (Qva/Qt) of 26%. The mean paO2 mmHg and the anatomical pulmonary artery to vein shunt (Qs/Qt) was 9%, with a DLco normal. The clinical hemodinamic correlation was in good agreement. Our results suggested that PAH-UE "per se" has effect in pulmonary function changing slight lung mechanics, and in a moderate degree lung gas exchange. The hipoxemia results meanly from V/Q imbalance.

Efficiency and regulation of water transport in some woody and herbaceous species.

The efficiency with which plants transport water is related to the water potential differences required to drive water fluxes from the soil to the leaf. A comparative study of two woody and three herbaceous species (Citrus sinensis L. cv. Koethen, Pyrus kawakami L., Helianthus annuus L. cv. Mammoth Russian, Capsicum frutescens L. cv. Yolo Wonder, and Sesamum indicum L. cv. Glauca) indicated contrasts in water transport efficiency. Depression of leaf water potential in response to transpiration increases was found in the woody species; the herbaceous species, however, had more efficient water transport systems and presented no measurable response of leaf water potential to transpiration changes. Different maximum transpiration rates under the same climatic conditions were observed with different species and may be accounted for by stomatal response to humidity gradients between leaf and air. Leaf diffusion resistance in sesame increased markedly as the humidity gradient was increased, while leaf resistance of sunflower responded less to humidity. Stomata appeared to respond directly to the humidity gradient because changes in leaf water potential were not detected when leaf resistance increased or decreased.

Osteointegração da hidroxiapatita sintética no processo alveolar da mandíbula de cães. Aspectos clínicos e radiográficos

O artigo não apresenta resumo.