Citrus is one of the major fruit crops in Cuba. Its perennial nature, the planted area and the time of productive exploitation turn it into a potential sink of atmospheric carbon. The present study was focused on the obtainment of two models that allow the quantitative estimation of carbon retention by citrus groves. The research was done in two commercial groves: orange [Citrus sinensis (L) Osbeck] cv. "Valencia Late" and grapefruit (Citrus paradisi Macf.) cv. "Marsh Seedless" both on sour orange (Citrus aurantium L.) and planted on a typical red ferralitic soil of Artemisa province. Groves are located at 22˚55' North and 82˚40' West. Cuba's climate is tropical, seasonally humid, with sea influence and semicontinentality features. Three issues were dealt with: 1) Determination of the total mean quantity of retained carbon by the aerial part of the trees using a destructive sampling method (Pattern Method) to estimate: the total volume of the tree, wood densities and green and dry biomass; 2) Determination of the total mean quantity of retained carbon by the aerial part of the trees using two Allometric Methods; and 3) Determination of the most effective Allometric Method to estimate the carbon retention by the aerial part of the trees. From the results, it is concluded that the evaluated methods were effective to reach a first quantitative approximation to carbon retention by citrus groves and under equal conditions, the Allometric Method 2 was more accurate to estimate the Total Carbon Content in "Valencia Late" orange, while for "Marsh Seedless" grapefruit the Allometric Method 1 provided the best estimate.

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Español.  San Miguel de Tucumán posee vegetación ornamental de carácter exótico y autóctono distribuída en calles y plazas. Con el objeto de facilitar la identificación de los granos de polen presentes tanto en sedimentos melíferos como en muestreos aerobiológicos locales, el presente trabajo continúa la descripción de la morfología polínica de la flora ornamental de esta ciudad. Se analizaron 10 especies arbóreas y arbustivas: Brachychiton populneus (Schott & Endl.) R. Br. (Malvaceae); Caesalpinia gilliesii (Wall. ex Hook.) D. Dietr. (Fabaceae); Campsis radicans (L) Bureau (Bignoniaceae); Euphorbia milii Des Moul. (Euphorbiaceae); Hibiscus rosa-sinensis L.; H. rosa-sinensis L. var. schizopetalus Boulger, H. mutabilis L., (Malvaceae); Hydrangea macrophylla (Thunb.) Ser. (Hydrangeaceae); Jacaranda mimosifolia D. Don (Bignoniaceae) y Ligustrum lucidum W.T. Aiton (Oleaceae). Las muestras provienen de material fresco y fueron procesadas según las técnicas convencionales de acetólisis y polen natural. Las preparaciones microscópicas fueron incorporadas a la Palinoteca (PAL-TUC) de la Fundación Miguel Lillo (FML). Se tomaron fotos con MO y MEB. Las descripciones polínicas amplían estudios previos realizados por diversos autores excepto en Hydrangea macrophylla y Jacaranda mimosifolia, de los que no encontramos referencias sobre morfología polínica en trabajos anteriores. De las especies estudiadas Ligustrum lucidum ha sido registrado en muestreos aerobiológicos. Brachychiton populneus, Hibiscus rosa-sinensis, Hibiscus rosa-sinensis var. schizopetalus y Euphorbia milii se han encontrado en muestras melisopalinológicas.Inglés. San Miguel de Tucumán has ornamental vegetation of exotic and indigenous character distributed in streets and squares. In order to facilitate identification of pollen grains present in melliferous sediments and aerobiological sampling, this study continues the description of the pollen morphology of the ornamental flora of this city. For the study, 10 arboreal and shrubby species were analyzed: Brachychiton populneus (Schott & Endl.) R. Br. (Malvaceae); Caesalpinia gilliesii (Wall. ex Hook.) D. Dietr. (Fabaceae); Campsis radicans (L) Bureau (Bignoniaceae); Euphorbia milii Des Moul. (Euphorbiaceae); Hibiscus rosa-sinensis L., H. rosa-sinensis L. var. schizopetalus Boulger, H. mutabilis L., (Malvaceae); Hydrangea macrophylla (Thunb.) Ser. (Hydrangeaceae); Jacaranda mimosifolia D. Don (Bignoniaceae); Ligustrum lucidum W.T. Aiton (Oleaceae). Samples obtained from fresh material were processed by conventional techniques of acetolysis and natural pollen. The microscopic preparations were incorporated into the Palinoteca (PAL-TUC) of the Fundación Miguel Lillo (FML). Pictures were taken with OM (optical microscope) and SEM (Scanning Electron Microscope). The pollen descriptions of this work extend previous studies made by various authors except in Hydrangea macrophylla and Jacaranda mimosifolia, of which no references on pollen morphology were found in previous works. Among the species studied, Ligustrum lucidum, was found in aero biological samples; whereas Brachychiton populneus, Hibiscus rosa-sinensis, H. rosa-sinensis. var. schizopetalus and Euphorbia milii were found in melisopalinological samples.

The current study attempts to describe the free time of City of Havana (Cuba) population older than 15 years, distinguishing between word days, weekends and vacation and holiday periods, determining the population's socio-demographic profile. The object population of study numbers over 1,720,445 people (2003), the selected sample is 1,144 individuals. The assumed sample error is ±3% with a confidence level of 95.5%. The technical quantitative analysis of data has been done using the SPSS/PC+ (V 14.0) computer program, which presents descriptive analyses of the different proposed variables, and using the program Elvira for the production of the Bayesian networks. Note in the results, that the availability of free time in work days are normal, increasing some in weekends and, is quite higher in vacation and holiday periods. The age and main activity are shown to be discriminating factors, being elders those with have more free time, and those with higher pro-fession who have less time.