First stages of zinc runoff in humid tropical climate

International Nuclear Information System (INIS)

Meraz, E.; Veleva, L.; Acosta, M.

2007-01-01

Frequently used metals in building application are Zinc and hot dip galvanized steel. The zinc has a relatively good atmospheric resistance, due to its oxidation in air and formation of protective layer. However, some of the zinc corrosion products can be dissolved by pluvial precipitations and water condensed on the metal surface. This process is called metal runoff. In order to estimate el zinc runoff in humid tropical climate, since its firs stages, samples of pure zinc and hot dip galvanized steel have been exposed during 2 years in outdoor atmosphere (rural and urban). The data reveal high annual values of zinc runoff (8,20-12,40±0.30 g/m''2 ano), being this process 80% of total mass loss of corroded zinc. The runoff and corrosion processes are more accelerated for zinc, than that of galvanized steel. The principal factors that control the runoff process are discussed. (Author) 48 refs

Analysis of humidity effects on growth and production of glasshouse fruit vegetables

NARCIS (Netherlands)

Bakker, J.C.

1991-01-01

Air humidity is a climate factor that can modify final yield and quality of crops through its impact on processes with a short as well as with a long response time. This thesis primarily deals with the long term responses of growth and production of glasshouse cucumber, tomato, sweet pepper and

Sediment Transport Capacity and Channel Processes in a Humid Tropical Montane River - Rio Pacuare, Costa Rica

Science.gov (United States)

Lind, P.; McDowell, P. F.

2017-12-01

Investigating sediment transport capacity as well as the spatial and temporal variations of sediment flux are critical component of river research, especially for applications in resource management and conservation, hazards assessment and planning, and riverine ecology. The bedload fraction of sediment transported through montane rivers often defines channel and bed form processes. It is understood that humid tropical montane rivers are capable of producing some of the largest quantities of sediment per unit drainage area. Bedload flux reported on a few Southeast Asian humid tropical montane rivers show that bedload constituted 16-75% of the total sediment load - this is notably higher than the generally accepted 10% of a channel's sediment load. However, to date almost all of the research done on sediment transport in humid tropical systems has focused on suspended load. This study presents annual bedload transport rate estimates for six field sites distributed within 45 river kilometers (Rkm) of the montane portion of the Rio Pacuare, located in the Talamanca Mountains of Costa Rica. This research reveals that flows capable of mobilizing the D84 occur on average at least once but often multiple times a year in this river system. The Rio Pacuare has a sufficient supply of sediment to meet its high transport capacity needs. As a result, large active bars composed of imbricated boulders define channel form at moderate and low flows throughout the study area. Differences in the magnitude, as well as the spatial and temporal variations of sediment flux at each field site are discussed in relation to stream power, and annual/inter-annual precipitation patterns. A unique mix of field and remote sensing techniques were applied to address these questions and to overcome some of the challenges of tropical river research. For example, due to the large grain size and high stream energy, grain mobilization and validation of modeled shear stress requirements for transport

Effect of climate on the seminal characteristics of boars in a region of humid tropical forest

International Nuclear Information System (INIS)

Henao Restrepo, Guillermo; Trujillo Aramburo, Luis Emilio; Buritica Henao, Maria Elizabet; Sierra Perez, Carlos Ignacio; Correa Londono, Guillermo; Gonzalez Boto, Oscar Domingo

2004-01-01

In a region of humid tropical forest, ten boars of from 12 to 24 months of age were selected to evaluate the effect of climatic variables measured on the day of semen collection and for each of preceding 45 days. On seminal characteristics, the variability of each characteristic was separated into an intra individual component and an interindividual component, using maximum likelihood estimators (PROC VARCOMP of SAS). In order to relate the seminal characteristics with the climatic variables, morphological abnormalities were grouped according to the affected spermatic region, into head. Midsection and main section abnormalities; the other characteristics were evaluated without any modification. Possible correlations between seminal characteristics and climatic variables were evaluated. In a total of 298 ejaculates collected weekly during a period of 30 weeks, except for total volume and morphological abnormalities. The seminal characteristics presented low or moderate intra and interindividual variation and were similar to those found in other latitudes, with a tendency to present greater seminal volumes and concentrations maximum temperature minimum temperature. Range among temperatures. Relative humidity and precipitation of the day of the semen collection and on each of the preceding 45 days had low effects on the seminal characteristics. It is possible that the boars in warm humid tropical areas develop a high level of adaptation that permits an adequate testicular thermoregulation that favors the spermatogenic function of the seminiferous tubules in a way that does not perceptibly affect production the seminal quality

Trace metal uptake by tropical vegetables grown on soil amended with urban sewage sludge

Energy Technology Data Exchange (ETDEWEB)

Nabulo, G.; Black, C.R. [School of Biosciences, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Young, S.D., E-mail: scott.young@nottingham.ac.u [School of Biosciences, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom)

2011-02-15

Trace metal uptake was measured for tropical and temperate leafy vegetables grown on soil from an urban sewage disposal farm in the UK. Twenty-four leafy vegetables from East Africa and the UK were assessed and the five vegetable types that showed the greatest Cd concentrations were grown on eight soils differing in the severity of contamination, pH and other physico-chemical properties. The range of Cd concentrations in the edible shoots was greater for tropical vegetables than for temperate types. Metal uptake was modelled as a function of (i) total soil metal concentration, (ii) CaCl{sub 2}-soluble metal, (iii) soil solution concentration and (iv) the activity of metal ions in soil pore water. Tropical vegetables were not satisfactorily modelled as a single generic 'green vegetable', suggesting that more sophisticated approaches to risk assessment may be required to assess hazard from peri-urban agriculture in developing countries. - Research highlights: Cadmium uptake by tropical green vegetables varies greatly between types. Modelling metal uptake works best for Ni, Cd and Zn but is poor for Cu, Ba and Pb. Modelling with dilute CaCl{sub 2} extraction is as good as metal ion activity in pore water. - Trace metal uptake by tropical leaf vegetables can be predicted from dilute CaCl{sub 2} extraction of soil but model parameters are genotype-specific.

Trace metal uptake by tropical vegetables grown on soil amended with urban sewage sludge

International Nuclear Information System (INIS)

Nabulo, G.; Black, C.R.; Young, S.D.

2011-01-01

Trace metal uptake was measured for tropical and temperate leafy vegetables grown on soil from an urban sewage disposal farm in the UK. Twenty-four leafy vegetables from East Africa and the UK were assessed and the five vegetable types that showed the greatest Cd concentrations were grown on eight soils differing in the severity of contamination, pH and other physico-chemical properties. The range of Cd concentrations in the edible shoots was greater for tropical vegetables than for temperate types. Metal uptake was modelled as a function of (i) total soil metal concentration, (ii) CaCl 2 -soluble metal, (iii) soil solution concentration and (iv) the activity of metal ions in soil pore water. Tropical vegetables were not satisfactorily modelled as a single generic 'green vegetable', suggesting that more sophisticated approaches to risk assessment may be required to assess hazard from peri-urban agriculture in developing countries. - Research highlights: → Cadmium uptake by tropical green vegetables varies greatly between types. → Modelling metal uptake works best for Ni, Cd and Zn but is poor for Cu, Ba and Pb. → Modelling with dilute CaCl 2 extraction is as good as metal ion activity in pore water. - Trace metal uptake by tropical leaf vegetables can be predicted from dilute CaCl 2 extraction of soil but model parameters are genotype-specific.

Hygroscopical behaviour of basic electrodes in a tropical humid climate. Comportamiento microscopico de ciertos electrodos revistidos de caracter basico en clima tropical humedo

Energy Technology Data Exchange (ETDEWEB)

Valencia, E.; Galeano, N.J.

1993-01-01

The study of the wetting kynetics of basic electrodes in a tropical humid climate is very important since the water contained in them is the main source for the atomic hydrogen absorbed by the fused metal during electric arc welding. It is also the origin of multiple defects in the added metal. A calculating method is established for evaluating the kynetics of wetness incorporation to the coating of basic electrodes exposed to a humid tropical climate. The method is based on the Fick's diffusion equation for both adequate system geometry and boundary conditions, which allows the evaluation of the effective diffusion coefficient and critical times of exposure to the different environments, along with the packing and storage conditions of electrodes. (Author)

Hygroscopical behaviour of basic electrodes in a tropical humid climate. Comportamiento microscopico de ciertos electrodos revistidos de caracter basico en clima tropical humedo

Energy Technology Data Exchange (ETDEWEB)

Valencia, E; Galeano, N J

1993-01-01

The study of the wetting kynetics of basic electrodes in a tropical humid climate is very important since the water contained in them is the main source for the atomic hydrogen absorbed by the fused metal during electric arc welding. It is also the origin of multiple defects in the added metal. A calculating method is established for evaluating the kynetics of wetness incorporation to the coating of basic electrodes exposed to a humid tropical climate. The method is based on the Fick's diffusion equation for both adequate system geometry and boundary conditions, which allows the evaluation of the effective diffusion coefficient and critical times of exposure to the different environments, along with the packing and storage conditions of electrodes. (Author)

On the relative role of fire and rainfall in determining vegetation patterns in tropical savannas: a simulation study

Science.gov (United States)

Spessa, Allan; Fisher, Rosie

2010-05-01

Tropical savannas cover 18% of the world's land surface and are amongst the most productive terrestrial systems in the world. They comprise 15% of the total terrestrial carbon stock, with an estimated mean net primary productivity (NPP) of 7.2 tCha-1yr-1 or two thirds of NPP in tropical forests. Tropical savannas are the most frequently burnt biome, with fire return intervals in highly productive areas being typically 1-2 years. Fires shape vegetation species composition, tree to grass ratios and nutrient redistribution, as well as the biosphere-atmosphere exchange of trace gases, momentum and radiative energy. Tropical savannas are a major source of emissions, contributing 38 % of total annual CO2 from biomass burning, 30% CO, 19 % CH4 and 59 % NOx. Climatically, they occur in regions subject to a strongly seasonal ‘wet-dry' regime, usually under monsoonal control from the movement of the inter-tropical convergence zone. In general, rainfall during the prior wet season(s) determines the amount of grass fuel available for burning while the length of the dry season influences fuel moisture content. Rainfall in tropical savannas exhibits high inter-annual variability, and under future climate change, is projected to change significantly in much of Africa, South America and northern Australia. Process-based simulation models of fire-vegetation dynamics and feedbacks are critical for determining the impacts of wildfires under projected future climate change on i) ecosystem structure and function, and ii) emissions of trace gases and aerosols from biomass burning. A new mechanistic global fire model SPITFIRE (SPread and InTensity of FIRE) has been designed to overcome many of the limitations in existing fire models set within Dynamic Global Vegetation Models (DGVMs). SPITFIRE has been applied in coupled mode globally and southern Africa, both as part of the LPJ DGVM. It has also been driven with MODIS burnt area data applied to sub-Saharan Africa, while coupled to the

Timber tree regeneration along abandoned logging roads in a tropical Bolivian forest

DEFF Research Database (Denmark)

Nabe-Nielsen, J.; Severiche, W.; Fredericksen, T.

2007-01-01

Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north-eastern Boli......Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north......-eastern Bolivia. Some species benefited from increased light intensities on abandoned logging roads. Others benefited from low densities of competing vegetation on roads with compacted soils. This was the case for the small-seeded species Ficus boliviana C.C. Berg and Terminalia oblonga (Ruiz & Pav.) Steud. Some...

Vegetation response to the "African Humid Period" termination in Central Cameroon (7° N – new pollen insight from Lake Mbalang

Directory of Open Access Journals (Sweden)

M. Servant

2010-05-01

Full Text Available A new pollen sequence from the Lake Mbalang (7°19´ N, 13°44´ E, 1110 m a.s.l. located on the eastern Adamawa plateau, in Central Cameroon, is presented in this paper to analyze the Holocene African Humid Period (AHP termination and related vegetation changes at 7° N in tropical Africa, completing an important transect for exploring shifts in the northern margin of the African Monsoon. This sequence, spanning the last 7000 cal yr BP, shows that the vegetation response to this transitional climatic period was marked by significant successional changes within the broad context of long-term aridification. Semi-deciduous/sub-montane forest retreat in this area is initially registered as early as ca. 6100 cal yr BP and modern savannah was definitely established at ca. 3000 cal yr BP and stabilized at ca. 2400 cal yr BP; but a slight forest regeneration episode is observed between ca. 5200 and ca. 4200 cal yr BP. In this area with modern high rainfall, increasing in the length of the dry season during the AHP termination linked to a contraction of the northern margin of the Intertropical Convergence Zone (ITCZ from ca. 6100 cal yr BP onward, probably associated with decreasing in cloud cover and/or fog frequency, has primarily controlled vegetation dynamics and above all the disappearance of the forested environment on the Adamawa plateau. Compared to previous studies undertaken in northern tropical and Central Africa, this work clearly shows that the response of vegetation to transitional periods between climatic extremes such as the AHP termination might be different in timing, mode and amplitude according to the regional climate of the study sites, but also according to the stability of vegetation before and during these climatic transitions.

Soil mineralogy and microbes determine forest life history strategy and carbon cycling in humid tropical forests

Science.gov (United States)

Soong, J.; Verbruggen, E.; Peñuelas, J.; Janssens, I. A.; Grau, O.

2017-12-01

Tropical forests account for over one third of global terrestrial gross primary productivity and cycle more C than any other ecosystem on Earth. However, we still lack a mechanistic understanding of how such high productivity is maintained on the old, highly weathered and phosphorus depleted soils in the tropics. We hypothesized that heterogeneity in soil texture, mineralogy and microbial community composition may be the major drivers of differences in soil C storage and P limitation across tropical forests. We sampled 12 forest sites across a 200 km transect in the humid neo-tropics of French Guiana that varied in soil texture, precipitation and mineralogy. We found that soil texture was a major driver of soil carbon stocks and forest life history strategy, where sandy forests have lower soil C stocks, slower turnover and decomposition and a more closed nutrient cycle while clayey forests have higher soil C stocks, faster turnover and a more leaky nutrient cycle (using natural abundance stable isotope evidence). We found that although the presence of Al and Fe oxides in the clayey soils occludes soil organic matter and P, a greater abundance of arbuscular mycorrhizal fungi help forests to access occluded P in clayey soils fueling higher turnover and faster decomposition rates. Evidence from a laboratory incubation of tropical soils with nutrient additions further demonstrates the de-coupling of microbial P demands from C:N limitations providing further evidence for the need to examine microbial stoichiometry to explain C cycling in the P-limited tropics. We argue that microbial community composition and physiological demands, constrained within the limitations of soil mineralogical reactivity, largely controls nutrient and C cycling in tropical forest soils. Together our observational field study and laboratory incubation provide a unique dataset to shed light on the mineralogical and microbial controls on C and nutrient cycling in tropical soils. By integrating

Linking Vital Rates of Landbirds on a Tropical Island to Rainfall and Vegetation Greenness.

Directory of Open Access Journals (Sweden)

James F Saracco

Full Text Available Remote tropical oceanic islands are of high conservation priority, and they are exemplified by range-restricted species with small global populations. Spatial and temporal patterns in rainfall and plant productivity may be important in driving dynamics of these species. Yet, little is known about environmental influences on population dynamics for most islands and species. Here we leveraged avian capture-recapture, rainfall, and remote-sensed habitat data (enhanced vegetation index [EVI] to assess relationships between rainfall, vegetation greenness, and demographic rates (productivity, adult apparent survival of three native bird species on Saipan, Northern Mariana Islands: rufous fantail (Rhipidura rufifrons, bridled white-eye (Zosterops conspicillatus, and golden white-eye (Cleptornis marchei. Rainfall was positively related to vegetation greenness at all but the highest rainfall levels. Temporal variation in greenness affected the productivity of each bird species in unique ways. Predicted productivity of rufous fantail was highest when dry and wet season greenness values were high relative to site-specific 5-year seasonal mean values (i.e., relative greenness; while the white-eye species had highest predicted productivity when relative greenness contrasted between wet and dry seasons. Survival of rufous fantail and bridled white eye was positively related to relative dry-season greenness and negatively related to relative wet-season greenness. Bridled white-eye survival also showed evidence of a positive response to overall greenness. Our results highlight the potentially important role of rainfall regimes in affecting population dynamics of species on oceanic tropical islands. Understanding linkages between rainfall, vegetation, and animal population dynamics will be critical for developing effective conservation strategies in this and other regions where the seasonal timing, extent, and variability of rainfall is expected to change in the

Physiological adaptation to the humid tropics with special reference to the West African Dwarf (WAD) goat.

Science.gov (United States)

Daramola, J O; Adeloye, A A

2009-10-01

West African Dwarf (WAD) goats are widely distributed in the subhumid and humid zones of Africa but are particularly associated with less favourable environments. Adaptive features such as feeding behaviour, efficiency of feed use and disease tolerance enable WAD goats to thrive on natural resources left untouched by other domestic ruminants. In marginal environments this goat remains the only domestic species that is able to survive. Among its physiological features small body size and low metabolic requirements are important traits that enable the animal to minimize its requirements in area or season where food sources are limited in quality and quantity. Specialized feeding behaviour and an efficient digestive system enable the animal to maximize food intake. Coat colour plays an important role in the evolved adaptation of this goat type. Reproductive fitness as manifested by prolific breeding is a major factor of adaptation. Defence mechanisms against infectious agents enable this type to thrive well in the hot humid tropics. The mechanisms involved in the regulation of these physiological functions of WAD goat are discussed. An understanding of these mechanisms could result in the development of improved techniques for enhancing goat productivity in humid environments.

The Role of Temperature and Humidity on Seasonal Influenza in Tropical Areas: Guatemala, El Salvador and Panama, 2008-2013

Science.gov (United States)

Soebiyanto, Radina P.; Clara, Wilfrido; Jara, Jorge; Castillo, Leticia; Sorto, Oscar Rene; Marinero, Sidia; Antinori, Maria E. Barnett de; McCracken, John P.; Widdowson, Marc-Alain; Azziz-Baumgartner, Eduardo;

Assessment of water availability and its relationship with vegetation distribution over a tropical montane system

Science.gov (United States)

Streher, A. S.; Sobreiro, J. F. F.; Silva, T. S. F.

2017-12-01

Water availability is one of the main drivers of vegetation distribution, but assessing it over mountainous regions is difficult given the effects of rugged topography on hydroclimatic dynamics (orographic rainfall, soil water, and runoff). We assessed how water availability may influence the distribution of vegetation types in the Espinhaço Range, a South American tropical mountain landscape comprised of savannas, grasslands, rock outcrops, cloud forests, and semi-deciduous/deciduous forests. For precipitation, we used CHIRPS monthly and daily products (1981- 2016) and 112 rain gauge ground stations, and assessed potential evapotranspiration (PET) using the MODIS MOD16A3 (2000-2013) product. Vegetation types were classified according to the Global Ecoregions by WWF. We show that rainfall has well-defined rainy and dry seasons with a strong latitudinal pattern, there is evidence for local orographic effects. Dry forests (907 mm/yr; 8% cv) and caatinga vegetation (795 mm/yr; 7% cv) had the lowest average annual precipitation and low variance, whilst Atlantic tropical forest in the southeast (1267 mm/yr; 15% cv), cerrado savanna vegetation in the west (1086 mm/yr; 15% cv) and rupestrian grasslands above 800m (1261 mm/yr; 20% cv) received the highest annual precipitation, with the largest observed variance due to their wide latitudinal distribution. Forests and rupestrian grasslands in the windward side of the mountain had a higher frequency of intense rainfall events (> 20mm), accounting for 6% of the CHIRPS daily time series, suggesting orographic effects on precipitation. Annual average PET was highest for dry forests (2437 mm/yr) and caatinga (2461 mm/yr), intermediate for cerrado (2264 mm/yr) and lowest for Atlantic tropical forest (2083 mm/yr) and rupestrian grasslands (2136 mm/yr). All vegetation types received less rainfall than its PET capacity based on yearly data, emphasizing the need for ecophysiological adaptations to water use. Climate change threatens

PAIR INFLUENCE OF WIND SPEED AND MEAN RADIANT TEMPERATURE ON OUTDOOR THERMAL COMFORT OF HUMID TROPICAL ENVIRONMENT

Directory of Open Access Journals (Sweden)

Sangkertadi Sangkertadi

2016-01-01

Full Text Available The purposes of this article is to explore knowledge of outdoor thermal comfort in humid tropical environment for urban activities especially for people in walking activity, and those who stationary/seated with moderate action. It will be characterized the pair influence of wind speed and radiant temperature on the outdoor thermal comfort. Many of researchers stated that those two microclimate variables give significant role on outdoor thermal comfort in tropical humid area. Outdoor Tropical Comfort (OTC model was used for simulation in this study. The model output is comfort scale that refers on ASHRAE definition. The model consists of two regression equations with variables of air temperature, globe temperature, wind speed, humidity and body posture, for two types of activity: walking and seated. From the results it can be stated that there is significant role of wind speed to reduce mean radiant temperature and globe temperature, when the velocity is elevated from 0.5 m/s to 2 m/s. However, the wind has not play significant role when the speed is changed from 2 m/s to 3.5 m/s. The results of the study may inspire us to implement effectiveness of electrical-fan equipment for outdoor space in order to get optimum wind speed, coupled with optimum design of shading devices to minimize radiant temperature for thermal comfort.

HadISDH: an updateable land surface specific humidity product for climate monitoring

Directory of Open Access Journals (Sweden)

K. M. Willett

2013-03-01

Full Text Available HadISDH is a near-global land surface specific humidity monitoring product providing monthly means from 1973 onwards over large-scale grids. Presented herein to 2012, annual updates are anticipated. HadISDH is an update to the land component of HadCRUH, utilising the global high-resolution land surface station product HadISD as a basis. HadISD, in turn, uses an updated version of NOAA's Integrated Surface Database. Intensive automated quality control has been undertaken at the individual observation level, as part of HadISD processing. The data have been subsequently run through the pairwise homogenisation algorithm developed for NCDC's US Historical Climatology Network monthly temperature product. For the first time, uncertainty estimates are provided at the grid-box spatial scale and monthly timescale. HadISDH is in good agreement with existing land surface humidity products in periods of overlap, and with both land air and sea surface temperature estimates. Widespread moistening is shown over the 1973–2012 period. The largest moistening signals are over the tropics with drying over the subtropics, supporting other evidence of an intensified hydrological cycle over recent years. Moistening is detectable with high (95% confidence over large-scale averages for the globe, Northern Hemisphere and tropics, with trends of 0.089 (0.080 to 0.098 g kg−1 per decade, 0.086 (0.075 to 0.097 g kg−1 per decade and 0.133 (0.119 to 0.148 g kg−1 per decade, respectively. These changes are outside the uncertainty range for the large-scale average which is dominated by the spatial coverage component; station and grid-box sampling uncertainty is essentially negligible on large scales. A very small moistening (0.013 (−0.005 to 0.031 g kg−1 per decade is found in the Southern Hemisphere, but it is not significantly different from zero and uncertainty is large. When globally averaged, 1998 is the moistest year since monitoring began in 1973, closely

Agroecology and healthy food systems in semi-humid tropical Africa: Participatory research with vulnerable farming households in Malawi.

Science.gov (United States)

Nyantakyi-Frimpong, Hanson; Kangmennaang, Joseph; Bezner Kerr, Rachel; Luginaah, Isaac; Dakishoni, Laifolo; Lupafya, Esther; Shumba, Lizzie; Katundu, Mangani

2017-11-01

This paper assesses the relationship between agroecology, food security, and human health. Specifically, we ask if agroecology can lead to improved food security and human health among vulnerable smallholder farmers in semi-humid tropical Africa. The empirical evidence comes from a cross-sectional household survey (n=1000) in two districts in Malawi, a small country in semi-humid, tropical Africa. The survey consisted of 571 agroecology-adoption and 429 non-agroecology-adoption households. Ordered logistics regression and average treatment effects models were used to determine the effect of agroecology adoption on self-reported health. Our results show that agroecology-adoption households (OR=1.37, p=0.05) were more likely to report optimal health status, and the average treatment effect shows that adopters were 12% more likely to be in optimal health. Furthermore, being moderately food insecure (OR=0.59, p=0.05) and severely food insecure (OR=0.89, p=0.10) were associated with less likelihood of reporting optimal health status. The paper concludes that with the adoption of agroecology in the semi-humid tropics, it is possible for households to diversify their crops and diets, a condition that has strong implications for improved food security, good nutrition and human health. Copyright © 2016 Elsevier B.V. All rights reserved.

Dynamic vegetation modeling of tropical biomes during Heinrich events

Science.gov (United States)

Handiani, Dian Noor; Paul, André; Dupont, Lydie M.

2010-05-01

Heinrich events are thought to be associated with a slowdown of the Atlantic Meridional Overturning Circulation (AMOC), which in turn would lead to a cooling of the North Atlantic Ocean and a warming of the South Atlantic Ocean (the "bipolar seesaw" hypothesis). The accompanying abrupt climate changes occurred not only in the ocean but also on the continents. Changes were strongest in the Northern Hemisphere but were registered in the tropics as well. Pollen data from Angola and Brazil showed that climate changes during Heinrich events affected vegetation patterns very differently in eastern South America and western Africa. To understand the differential response in the terrestrial tropics, we studied the vegetation changes during Heinrich events by using a dynamic global vegetation model (TRIFFID) as part of the University of Victoria (UVic) Earth System-Climate Model (ESCM). The model results show a bipolar seesaw pattern in temperature and precipitation during a near-collapse of the AMOC. The succession in plant-functional types (PFTs) showed changes from forest to shrubs to desert, including spreading desert in northwest Africa, retreating broadleaf trees in West Africa and northern South America, but advancing broadleaf trees in Brazil. The pattern is explained by a southward shift of the tropical rainbelt resulting in a strong decrease in precipitation over northwest and West Africa as well as in northern South America, but an increase in precipitation in eastern Brazil. To facilitate the comparison between modeled vegetation results with pollen data, we diagnosed the distribution of biomes from the PFT coverage and the simulated model climate. The biome distribution was computed for Heinrich event 1 and the Last Glacial Maximum as well as for pre-industrial conditions. We used a classification of biomes in terms of "mega-biomes", which were defined following a scheme originally proposed by BIOME 6000 (v 4.2). The biome distribution of the Sahel region

Taxonomy and remote sensing of leaf mass per area (LMA) in humid tropical forests

Science.gov (United States)

Gregory P. Asner; Roberta E. Martin; Raul Tupayachi; Ruth Emerson; Paola Martinez; Felipe Sinca; George V.N. Powell; S. Joseph Wright; Ariel E. Lugo

2011-01-01

Leaf mass per area (LMA) is a trait of central importance to plant physiology and ecosystem function, but LMA patterns in the upper canopies of humid tropical forests have proved elusive due to tall species and high diversity. We collected top-of-canopy leaf samples from 2873 individuals in 57 sites spread across the Neotropics, Australasia, and Caribbean and Pacific...

Comparing MODIS and near-surface vegetation indexes for monitoring tropical dry forest phenology along a successional gradient using optical phenology towers

Science.gov (United States)

Rankine, C.; Sánchez-Azofeifa, G. A.; Guzmán, J. Antonio; Espirito-Santo, M. M.; Sharp, Iain

2017-10-01

Tropical dry forests (TDFs) present strong seasonal greenness signals ideal for tracking phenology and primary productivity using remote sensing techniques. The tightly synchronized relationship these ecosystems have with water availability offer a valuable natural experiment for observing the complex interactions between the atmosphere and the biosphere in the tropics. To investigate how well the MODIS vegetation indices (normalized difference vegetation index (NDVI) and the enhanced vegetation index (EVI)) represented the phenology of different successional stages of naturally regenerating TDFs, within a widely conserved forest fragment in the semi-arid southeast of Brazil, we installed several canopy towers with radiometric sensors to produce high temporal resolution near-surface vegetation greenness indices. Direct comparison of several years of ground measurements with a combined Aqua/Terra 8 day satellite product showed similar broad temporal trends, but MODIS often suffered from cloud contamination during the onset of the growing season and occasionally during the peak growing season. The strength of the in-situ and MODIS linear relationship was greater for NDVI than for EVI across sites but varied with forest stand age. Furthermore, we describe the onset dates and duration of canopy development phases for three years of in-situ monitoring. A seasonality analysis revealed significant discrepancies between tower and MODIS phenology transitions dates, with up to five weeks differences in growing season length estimation. Our results indicate that 8 and 16 day MODIS satellite vegetation monitoring products are suitable for tracking general patterns of tropical dry forest phenology in this region but are not temporally sufficient to characterize inter-annual differences in phenology phase onset dates or changes in productivity due to mid-season droughts. Such rapid transitions in canopy greenness are important indicators of climate change sensitivity of these

Constrained parameterisation of photosynthetic capacity causes significant increase of modelled tropical vegetation surface temperature

Science.gov (United States)

Kattge, J.; Knorr, W.; Raddatz, T.; Wirth, C.

2009-04-01

Photosynthetic capacity is one of the most sensitive parameters of terrestrial biosphere models whose representation in global scale simulations has been severely hampered by a lack of systematic analyses using a sufficiently broad database. Due to its coupling to stomatal conductance changes in the parameterisation of photosynthetic capacity may potentially influence transpiration rates and vegetation surface temperature. Here, we provide a constrained parameterisation of photosynthetic capacity for different plant functional types in the context of the photosynthesis model proposed by Farquhar et al. (1980), based on a comprehensive compilation of leaf photosynthesis rates and leaf nitrogen content. Mean values of photosynthetic capacity were implemented into the coupled climate-vegetation model ECHAM5/JSBACH and modelled gross primary production (GPP) is compared to a compilation of independent observations on stand scale. Compared to the current standard parameterisation the root-mean-squared difference between modelled and observed GPP is substantially reduced for almost all PFTs by the new parameterisation of photosynthetic capacity. We find a systematic depression of NUE (photosynthetic capacity divided by leaf nitrogen content) on certain tropical soils that are known to be deficient in phosphorus. Photosynthetic capacity of tropical trees derived by this study is substantially lower than standard estimates currently used in terrestrial biosphere models. This causes a decrease of modelled GPP while it significantly increases modelled tropical vegetation surface temperatures, up to 0.8°C. These results emphasise the importance of a constrained parameterisation of photosynthetic capacity not only for the carbon cycle, but also for the climate system.

Amplification of wildfire area burnt by hydrological drought in the humid tropics

Science.gov (United States)

Taufik, Muh; Torfs, Paul J. J. F.; Uijlenhoet, Remko; Jones, Philip D.; Murdiyarso, Daniel; van Lanen, Henny A. J.

2017-06-01

Borneo's diverse ecosystems, which are typical humid tropical conditions, are deteriorating rapidly, as the area is experiencing recurrent large-scale wildfires, affecting atmospheric composition and influencing regional climate processes. Studies suggest that climate-driven drought regulates wildfires, but these overlook subsurface processes leading to hydrological drought, an important driver. Here, we show that models which include hydrological processes better predict area burnt than those solely based on climate data. We report that the Borneo landscape has experienced a substantial hydrological drying trend since the early twentieth century, leading to progressive tree mortality, more severe than in other tropical regions. This has caused massive wildfires in lowland Borneo during the past two decades, which we show are clustered in years with large areas of hydrological drought coinciding with strong El Niño events. Statistical modelling evidence shows amplifying wildfires and greater area burnt in response to El Niño/Southern Oscillation (ENSO) strength, when hydrology is considered. These results highlight the importance of considering hydrological drought for wildfire prediction, and we recommend that hydrology should be considered in future studies of the impact of projected ENSO strength, including effects on tropical ecosystems, and biodiversity conservation.

Biological effects of plant residues with constrasting chemical compositions on plant and soil under humid tropical conditions

NARCIS (Netherlands)

Tian, G.

1992-01-01

A study on plant residues with contrasting chemical compositions was conducted under laboratory, growth chamber and humid tropical field conditions to understand the function of the soil fauna in the breakdown of plant residues, the cycling of nutrients, in particular nitrogen, and the

Vegetation cover in relation to socioeconomic factors in a tropical city assessed from sub-meter resolution imagery.

Science.gov (United States)

Martinuzzi, Sebastián; Ramos-González, Olga M; Muñoz-Erickson, Tischa A; Locke, Dexter H; Lugo, Ariel E; Radeloff, Volker C

2018-04-01

Fine-scale information about urban vegetation and social-ecological relationships is crucial to inform both urban planning and ecological research, and high spatial resolution imagery is a valuable tool for assessing urban areas. However, urban ecology and remote sensing have largely focused on cities in temperate zones. Our goal was to characterize urban vegetation cover with sub-meter (urban vegetation patterns in a tropical city, the San Juan Metropolitan Area, Puerto Rico. Our specific objectives were to (1) map vegetation cover using sub-meter spatial resolution (0.3-m) imagery, (2) quantify the amount of residential and non-residential vegetation, and (3) investigate the relationship between patterns of urban vegetation vs. socioeconomic and environmental factors. We found that 61% of the San Juan Metropolitan Area was green and that our combination of high spatial resolution imagery and object-based classification was highly successful for extracting vegetation cover in a moist tropical city (97% accuracy). In addition, simple spatial pattern analysis allowed us to separate residential from non-residential vegetation with 76% accuracy, and patterns of residential and non-residential vegetation varied greatly across the city. Both socioeconomic (e.g., population density, building age, detached homes) and environmental variables (e.g., topography) were important in explaining variations in vegetation cover in our spatial regression models. However, important socioeconomic drivers found in cities in temperate zones, such as income and home value, were not important in San Juan. Climatic and cultural differences between tropical and temperate cities may result in different social-ecological relationships. Our study provides novel information for local land use planners, highlights the value of high spatial resolution remote sensing data to advance ecological research and urban planning in tropical cities, and emphasizes the need for more studies in tropical

Diurnal Thermal Behavior of Pavements, Vegetation, and Water Pond in a Hot-Humid City

Directory of Open Access Journals (Sweden)

Xiaoshan Yang

2015-12-01

Full Text Available This study investigated the diurnal thermal behavior of several urban surfaces and landscape components, including pavements, vegetation, and a water pond. The field experiment was conducted in a university campus of Guangzhou, South China, which is characterized by a hot and humid summer. The temperature of ground surface and grass leaves and the air temperature and humidity from 0.1 to 1.5 m heights were measured for a period of 24 h under hot summer conditions. The results showed that the concrete and granite slab pavements elevated the temperature of the air above them throughout the day. In contrast, the trees and the pond lowered the air temperature near ground during the daytime but produced a slight warming effect during the nighttime. The influence of vegetation on air temperature and humidity is affected by the configurations of greenery. Compared to the open lawn, the grass shaded by trees was more effective in cooling and the mixture of shrub and grass created a stronger cooling effect during the nighttime. The knowledge of thermal behavior of various urban surfaces and landscape components is an important tool for planners and designers. If utilized properly, it can lead to climatic rehabilitation in urban areas and an improvement of the outdoor thermal environment.

Tropical climate and vegetation changes during Heinrich Event 1: a model-data comparison

Directory of Open Access Journals (Sweden)

D. Handiani

2012-01-01

Full Text Available Abrupt climate changes from 18 to 15 thousand years before present (kyr BP associated with Heinrich Event 1 (HE1 had a strong impact on vegetation patterns not only at high latitudes of the Northern Hemisphere, but also in the tropical regions around the Atlantic Ocean. To gain a better understanding of the linkage between high and low latitudes, we used the University of Victoria (UVic Earth System-Climate Model (ESCM with dynamical vegetation and land surface components to simulate four scenarios of climate-vegetation interaction: the pre-industrial era, the Last Glacial Maximum (LGM, and a Heinrich-like event with two different climate backgrounds (interglacial and glacial. We calculated mega-biomes from the plant-functional types (PFTs generated by the model to allow for a direct comparison between model results and palynological vegetation reconstructions.

Our calculated mega-biomes for the pre-industrial period and the LGM corresponded well with biome reconstructions of the modern and LGM time slices, respectively, except that our pre-industrial simulation predicted the dominance of grassland in southern Europe and our LGM simulation resulted in more forest cover in tropical and sub-tropical South America.

The HE1-like simulation with a glacial climate background produced sea-surface temperature patterns and enhanced inter-hemispheric thermal gradients in accordance with the "bipolar seesaw" hypothesis. We found that the cooling of the Northern Hemisphere caused a southward shift of those PFTs that are indicative of an increased desertification and a retreat of broadleaf forests in West Africa and northern South America. The mega-biomes from our HE1 simulation agreed well with paleovegetation data from tropical Africa and northern South America. Thus, according to our model-data comparison, the reconstructed vegetation changes for the tropical regions around the Atlantic Ocean were physically consistent with the remote

Observations of increased tropical rainfall preceded by air passage over forests.

Science.gov (United States)

Spracklen, D V; Arnold, S R; Taylor, C M

2012-09-13

Vegetation affects precipitation patterns by mediating moisture, energy and trace-gas fluxes between the surface and atmosphere. When forests are replaced by pasture or crops, evapotranspiration of moisture from soil and vegetation is often diminished, leading to reduced atmospheric humidity and potentially suppressing precipitation. Climate models predict that large-scale tropical deforestation causes reduced regional precipitation, although the magnitude of the effect is model and resolution dependent. In contrast, observational studies have linked deforestation to increased precipitation locally but have been unable to explore the impact of large-scale deforestation. Here we use satellite remote-sensing data of tropical precipitation and vegetation, combined with simulated atmospheric transport patterns, to assess the pan-tropical effect of forests on tropical rainfall. We find that for more than 60 per cent of the tropical land surface (latitudes 30 degrees south to 30 degrees north), air that has passed over extensive vegetation in the preceding few days produces at least twice as much rain as air that has passed over little vegetation. We demonstrate that this empirical correlation is consistent with evapotranspiration maintaining atmospheric moisture in air that passes over extensive vegetation. We combine these empirical relationships with current trends of Amazonian deforestation to estimate reductions of 12 and 21 per cent in wet-season and dry-season precipitation respectively across the Amazon basin by 2050, due to less-efficient moisture recycling. Our observation-based results complement similar estimates from climate models, in which the physical mechanisms and feedbacks at work could be explored in more detail.

Management and conservation of tropical acid soils for sustainable crop production. Proceedings of a consultants meeting

International Nuclear Information System (INIS)

2000-06-01

Forests of the tropics are invaluable ecosystems of global, regional and local importance, particularly in terms of protection and conservation of biodiversity and water resources. The indiscriminate conversion of tropical forests into agricultural land as a result of intense human activities - logging and modem shifting cultivation - continues to cause soil erosion and degradation. However, the acid savannahs of the world, such as the cerrado of Brazil, the Llanos in Venezuela and Colombia, the savannahs of Africa, and the largely anthropic savannahs of tropical Asia, encompass vast areas of potentially arable land. The acid soils of the savannahs are mostly considered marginal because of low inherent fertility and susceptibility to rapid degradation. These constraints for agricultural development are exacerbated by the poverty of new settlers who try to cultivate such areas after deforestation. Low- or minimum-input systems are not sustainable on these tropical acid soils but, with sufficient investment and adequate technologies, they can be highly productive. Thus, there is a need to develop management practices for sustainable agricultural production systems on such savannah acid soils. The Soil and Water Management and Crop Nutrition Sub-programme of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture strongly supports an integrated approach to soil, water and nutrient management within cropping systems. In this context, nuclear and related techniques can be used to better understand the processes and factors influencing the productivity of agricultural production systems, and improve them through the use of better soil, water and nutrient management practices. A panel of experts actively engaged in field projects on acid soils of savannah agro-ecosystems in the humid and sub-humid tropics convened in March 1999 in Vienna to review and discuss recent research progress, along the following main lines of investigation: (i) utilization of

National satellite-based humid tropical forest change assessment in Peru in support of REDD+ implementation

Science.gov (United States)

Potapov, P. V.; Dempewolf, J.; Talero, Y.; Hansen, M. C.; Stehman, S. V.; Vargas, C.; Rojas, E. J.; Castillo, D.; Mendoza, E.; Calderón, A.; Giudice, R.; Malaga, N.; Zutta, B. R.

2014-12-01

Transparent, consistent, and accurate national forest monitoring is required for successful implementation of reducing emissions from deforestation and forest degradation (REDD+) programs. Collecting baseline information on forest extent and rates of forest loss is a first step for national forest monitoring in support of REDD+. Peru, with the second largest extent of Amazon basin rainforest, has made significant progress in advancing its forest monitoring capabilities. We present a national-scale humid tropical forest cover loss map derived by the Ministry of Environment REDD+ team in Peru. The map quantifies forest loss from 2000 to 2011 within the Peruvian portion of the Amazon basin using a rapid, semi-automated approach. The available archive of Landsat imagery (11 654 scenes) was processed and employed for change detection to obtain annual gross forest cover loss maps. A stratified sampling design and a combination of Landsat (30 m) and RapidEye (5 m) imagery as reference data were used to estimate the primary forest cover area, total gross forest cover loss area, proportion of primary forest clearing, and to validate the Landsat-based map. Sample-based estimates showed that 92.63% (SE = 2.16%) of the humid tropical forest biome area within the country was covered by primary forest in the year 2000. Total gross forest cover loss from 2000 to 2011 equaled 2.44% (SE = 0.16%) of the humid tropical forest biome area. Forest loss comprised 1.32% (SE = 0.37%) of primary forest area and 9.08% (SE = 4.04%) of secondary forest area. Validation confirmed a high accuracy of the Landsat-based forest cover loss map, with a producer’s accuracy of 75.4% and user’s accuracy of 92.2%. The majority of forest loss was due to clearing (92%) with the rest attributed to natural processes (flooding, fires, and windstorms). The implemented Landsat data processing and classification system may be used for operational annual forest cover loss updates at the national level for REDD

National satellite-based humid tropical forest change assessment in Peru in support of REDD+ implementation

International Nuclear Information System (INIS)

Potapov, P V; Dempewolf, J; Talero, Y; Hansen, M C; Stehman, S V; Vargas, C; Rojas, E J; Calderón, A; Giudice, R; Malaga, N; Zutta, B R; Castillo, D; Mendoza, E

2014-01-01

Transparent, consistent, and accurate national forest monitoring is required for successful implementation of reducing emissions from deforestation and forest degradation (REDD+) programs. Collecting baseline information on forest extent and rates of forest loss is a first step for national forest monitoring in support of REDD+. Peru, with the second largest extent of Amazon basin rainforest, has made significant progress in advancing its forest monitoring capabilities. We present a national-scale humid tropical forest cover loss map derived by the Ministry of Environment REDD+ team in Peru. The map quantifies forest loss from 2000 to 2011 within the Peruvian portion of the Amazon basin using a rapid, semi-automated approach. The available archive of Landsat imagery (11 654 scenes) was processed and employed for change detection to obtain annual gross forest cover loss maps. A stratified sampling design and a combination of Landsat (30 m) and RapidEye (5 m) imagery as reference data were used to estimate the primary forest cover area, total gross forest cover loss area, proportion of primary forest clearing, and to validate the Landsat-based map. Sample-based estimates showed that 92.63% (SE = 2.16%) of the humid tropical forest biome area within the country was covered by primary forest in the year 2000. Total gross forest cover loss from 2000 to 2011 equaled 2.44% (SE = 0.16%) of the humid tropical forest biome area. Forest loss comprised 1.32% (SE = 0.37%) of primary forest area and 9.08% (SE = 4.04%) of secondary forest area. Validation confirmed a high accuracy of the Landsat-based forest cover loss map, with a producer’s accuracy of 75.4% and user’s accuracy of 92.2%. The majority of forest loss was due to clearing (92%) with the rest attributed to natural processes (flooding, fires, and windstorms). The implemented Landsat data processing and classification system may be used for operational annual forest cover loss updates at the national level

Soil bioengineering for risk mitigation and environmental restoration in a humid tropical area

Science.gov (United States)

Petrone, A.; Preti, F.

2010-02-01

The use of soil bio-engineering techniques in developing countries is a relevant issue for disaster mitigation, environmental restoration and poverty reduction. Research on the autochthonal plants suitable for these kinds of interventions and on the economic efficiency of the interventions is essential for the dissemination of such techniques. The present paper is focused on these two issues as related to the realization of various typologies of soil bioengineering works in the humid tropics of Nicaragua. In the area of Río Blanco, located in the Department of Matagalpa, soil bioengineering installations were built in several sites. The particular structures built were: drainages with live fascine mattress, a live palisade, a vegetated live crib wall for riverbank protection, a vegetative covering made of a metallic net and biotextile coupled with a live palisade made of bamboo. In order to evaluate the suitability of the various plants used in these works, monitoring was performed, one on the live palisade alongside an unpaved road and the other on the live crib wall along a riverbank, by collecting data on survival rate and morphological parameters. Concerning economic efficiency, we proceeded to a financial analysis of the works. Once the unit price was obtained, we converted the amount into EPP Dollars (Equal Purchasing Power) in order to compare the Nicaraguan context with the European one. Among the species used we found that Gliricidia sepium (local common name: Madero negro) and Tabebuia rosea (local common name: Roble macuelizo) are adequate for soil bioengineering measures on slopes, while Erythrina fusca (local common name: Helequeme) resulted in successful behaviour only in the crib wall for riverbank protection. In comparing costs in Nicaragua and in Italy, the unit price reduction for Nicaragua ranges from 1.5 times (for the vegetative covering) to almost 4 times (for the fascine mattress), using the EPP dollar exchange rate. Our conclusions with

Comparisons of urban and rural heat stress conditions in a hot–humid tropical city

Directory of Open Access Journals (Sweden)

Ahmed A. Balogun

2010-11-01

Full Text Available Background: In recent years the developing world, much of which is located in the tropical countries, has seen dramatic growth of its urban population associated with serious degradation of environmental quality. Climate change is producing major impacts including increasing temperatures in these countries that are considered to be most vulnerable to the impact of climate change due to inadequate public health infrastructure and low income status. However, relevant information and data for informed decision making on human health and comfort are lacking in these countries. Objective: The aim of this paper is to study and compare heat stress conditions in an urban (city centre and rural (airport environments in Akure, a medium-sized tropical city in south-western Nigeria during the dry harmattan season (January–March of 2009. Materials and methods: We analysed heat stress conditions in terms of the mean hourly values of the thermohygrometric index (THI, defined by simultaneous in situ air temperature and relative humidity measurements at both sites. Results: The urban heat island (UHI exists in Akure as the city centre is warmer than the rural airport throughout the day. However, the maximum UHI intensity occurs at night between 1900 and 2200 hours local time. Hot conditions were predominant at both sites, comfortable conditions were only experienced in the morning and evenings of January at both sites, but the rural area has more pleasant morning and evenings and less of very hot and torrid conditions. January has the lowest frequency of hot and torrid conditions at both sites, while March and February has the highest at the city centre and the airport, respectively. The higher frequencies of high temperatures in the city centre suggest a significant heat stress and health risk in this hot humid environment of Akure. Conclusions: More research is needed to achieve better understanding of the seasonal variation of indoor and outdoor heat stress

On the delineation of tropical vegetation types with an emphasis on forest/savanna transitions

NARCIS (Netherlands)

Torello-Raventos, M.; Feldpausch, T.R.; Veenendaal, E.M.; Sykora, K.V.

2013-01-01

Background: There is no generally agreed classification scheme for the many different vegetation formation types occurring in the tropics. This hinders cross-continental comparisons and causes confusion as words, such as ‘forest’ and ‘savanna’ have different meanings to different people. Tropical

Climate change and spatial distribution of vegetation in Colombia

Directory of Open Access Journals (Sweden)

Juan Carlos Alarcon Hincapie

2013-12-01

Full Text Available Vegetation change under two climate change scenarios in different periods of the 21st Century are modeled for Colombia. Vegetation for the years 1970 to 2000 was reproduced using the Holdridge model with climate data with a spatial resolution of 900 meters. The vegetation types that occupied the most territory were sub-humid tropical forest, tropical dry forest and Andean wet forest. These results were validated by comparing with the Colombian ecosystem map (SINA, 2007, which confirmed a high degree of similarity between the modeled spatial vegetation patterns and modern ecosystem distributions. Future vegetation maps were simulated using data generated by a regional climate model under two scenarios (A2 and B2; IPCC, 2007 for the periods 2011-2040 and 2070-2100. Based on our predictions high altitude vegetation will convert to that of lower altitudes and drier provinces with the most dramatic change occurring in the A2 scenario from 2070-2100. The most affected areas are the páramo and other high Andean vegetation types, which in the timeframe of the explored scenarios will disappear by the middle of the 21st Century.

Corrosion and Deterioration Testing in the Humid Tropic Environments

Science.gov (United States)

2014-07-21

specimens while transporting the retrieved specimens back to the laboratories for detailed analysis . Preferably, each specimen should be wrapped...VEGETATION. Some types of vegetation tend to exude tannins , sugars, and other natural plant products which may support microbial growth and corrosion

Testing the ecotoxicology of vegetable versus mineral based lubricating oils: 2. Induction of mixed function oxidase enzymes in barramundi, Lates calcarifer, a tropical fish species

International Nuclear Information System (INIS)

Mercurio, Philip; Burns, Kathryn A.; Cavanagh, Joanne

2004-01-01

An increasing number of vegetable-based oils are being developed as environmentally friendly alternatives to petroleum products. However, toxicity towards key tropical marine species has not been investigated. In this study we used laboratory-based biomarker induction experiments to compare the relative stress of a vegetable-based lubricating oil for marine 2-stroke engines with its mineral oil-based counterpart on tropical fish. The sub-lethal stress of 2-stoke outboard lubricating oils towards the fish Lates calcarifer (barramundi) was examined using liver microsomal mixed function oxidase (MFO) induction assays. This study is the first investigation into the use of this key commercial species in tropical North Queensland, Australia in stress assessment of potential hydrocarbon pollution using ethoxyresorufin O-deethylase (EROD) induction. Our results indicated that barramundi provide a wide range of inducible rates of EROD activity in response to relevant organic stressors. The vegetable- and mineral-based lubricants induced significant EROD activity at 1.0 mg kg -1 and there was no significant difference between the two oil treatments at that concentration. At increasing concentrations of 2 and 3 mg kg -1 , the mineral-based lubricant resulted in slightly higher EROD activity than the vegetable-based lubricant. The EROD activity of control and treated barramundi are found to be within ranges for other species from temperate and tropical environments. These results indicate that vegetable-based lubricants may be less stressful to barramundi than their mineral counterparts at concentrations of lubricant ≥2 mg kg -1 . There is great potential for this species to be used in the biomonitoring of waterways around tropical North Queensland and SE Asia. - Vegetable-based lubricating oils appear to cause a tropical fish species less stress than mineral oils

Testing the ecotoxicology of vegetable versus mineral based lubricating oils: 2. Induction of mixed function oxidase enzymes in barramundi, Lates calcarifer, a tropical fish species

Energy Technology Data Exchange (ETDEWEB)

Mercurio, Philip; Burns, Kathryn A.; Cavanagh, Joanne

2004-05-01

An increasing number of vegetable-based oils are being developed as environmentally friendly alternatives to petroleum products. However, toxicity towards key tropical marine species has not been investigated. In this study we used laboratory-based biomarker induction experiments to compare the relative stress of a vegetable-based lubricating oil for marine 2-stroke engines with its mineral oil-based counterpart on tropical fish. The sub-lethal stress of 2-stoke outboard lubricating oils towards the fish Lates calcarifer (barramundi) was examined using liver microsomal mixed function oxidase (MFO) induction assays. This study is the first investigation into the use of this key commercial species in tropical North Queensland, Australia in stress assessment of potential hydrocarbon pollution using ethoxyresorufin O-deethylase (EROD) induction. Our results indicated that barramundi provide a wide range of inducible rates of EROD activity in response to relevant organic stressors. The vegetable- and mineral-based lubricants induced significant EROD activity at 1.0 mg kg{sup -1} and there was no significant difference between the two oil treatments at that concentration. At increasing concentrations of 2 and 3 mg kg{sup -1}, the mineral-based lubricant resulted in slightly higher EROD activity than the vegetable-based lubricant. The EROD activity of control and treated barramundi are found to be within ranges for other species from temperate and tropical environments. These results indicate that vegetable-based lubricants may be less stressful to barramundi than their mineral counterparts at concentrations of lubricant {>=}2 mg kg{sup -1}. There is great potential for this species to be used in the biomonitoring of waterways around tropical North Queensland and SE Asia. - Vegetable-based lubricating oils appear to cause a tropical fish species less stress than mineral oils.

A Drone-based Tropical Forest Experiment to Estimate Vegetation Properties

Science.gov (United States)

Henke, D.

2017-12-01

In mid-latitudes, remote sensing technology is intensively used to monitor vegetation properties. However, in the tropics, high cloud-cover and saturation effects of vegetation indices (VI) hamper the reliability of vegetation parameters derived from satellite data. A drone experiment over the Barro Colorado Island (BCI), Panama, with high temporal repetition rates was conducted in spring 2017 to investigate the robustness and stability of remotely sensed vegetation parameters in tropical environments. For this purpose, three 10-day flight windows in February, March and April were selected and drone flights were repeated on daily intervals when weather conditions and equipment allowed it. In total, 18 days were recorded with two different optical cameras on sensefly's eBee drone: one red, green, blue (RGB) camera and one camera with near infra-red (NIR), green and blue channels. When possible, the data were acquired at the same time of day. Pix4D and Agisoft software were used to calculate the Normalized Difference VI (NDVI) and forest structure. In addition, leave samples were collected ones per month from 16 different plant species and the relative water content was measured as ground reference. Further data sources for the analysis are phenocam images (RGB & NIR) on BCI and satellite images of MODIS (NDVI; Enhanced VI EVI) and Sentinel-1 (radar backscatter). The attached figure illustrates the main data collected on BCI. Initial results suggest that the coefficient of determination (R2) is relatively high between ground samples and drone data, Sentinel-1 backscatter and MODIS EVI with R2 values ranging from 0.4 to 0.6; on the contrary, R2 values between ground measurements and MODIS NDVI or phenocam images are below 0.2. As the experiment took place mainly during dry season on BCI, cloud-cover rates are less dominate than during wet season. Under these conditions, MODIS EVI, which is less vulnerable to saturation effects, seems to be more reliable than MODIS

Glutamine and glutamic acid supplementation enhances performance of broiler chickens under the hot and humid tropical condition

Directory of Open Access Journals (Sweden)

Joshua O. Olubodun

2015-02-01

Full Text Available Day-old (day 1 commercial broiler chickens were fed i basal diet (control, ii basal diet +0.5% AminoGut (AG, or iii basal diet +1% AG from 1 to 42 d of age under the hot and humid tropical environment. AminoGut is a commercial dietary supplement containing a mixture of L-glutamine (Gln and L-glutamic (Glu acid. Weight gain and feed conversion ratio during the starter (1 to 21 d and overall (1 to 42 d periods improved linearly and quadratically with AG supplementation when compared to control. Supplementing birds with AG significantly reduced overall mortality rate. At 21 and 42 d of age, intestinal (duodenum and ileum villi height and crypt depth showed both linear and quadratic positive responses to AG supplementation. Intestinal amylase activity increased linearly and quadratically on d 21, and linearly only on d 42. In conclusion, Gln and Glu supplementation was beneficial in improving the growth performance and survivability of broiler chickens under the hot and humid tropical environment.

Termites as ecological indicators of mine-land rehabilitation in tropical Australia

International Nuclear Information System (INIS)

Hinz, D.A.

2001-01-01

This paper presents examples from field research of termites as indicators of rehabilitation success in the wet-dry tropics at Nabalco's bauxite mine, Gove, Australia and in Sierra Leone, West Africa. Field studies indicate that soil-plant-animal interactions are crucial in determining the recovery of disturbed land and that termites play an over-riding role in the process. Termites are seen as ecological indicators for successful soil and vegetation development in humid tropical environments. In land rehabilitation, termites help to create healthy, self-regulated vegetation systems that integrate with the surrounding landscapes and build structures and functions equal to those of the pre-disturbed system. They are reliable in signaling the health and stress factors of a system and provide a predictable response

Heavy metals in vegetables collected from production and market sites of a tropical urban area of India.

Science.gov (United States)

Sharma, Rajesh Kumar; Agrawal, Madhoolika; Marshall, Fiona M

2009-03-01

Vegetables (Beta vulgaris L., Abelmoschus esculentus L. and Brassica oleracea L.) from the production and market sites of India were tested for Cu, Cd, Zn and Pb. At market sites, the mean concentration of Cu in cauliflower, and of Zn and Cd in both palak and cauliflower had exceeded the PFA standard. Zn at the production sites also exceeded the PFA standard in cauliflower. Cd concentration in vegetables tested from both production and market sites was many folds higher than the EU standard. In contrast, Pb in vegetables tested from both production and market sites was below the PFA limit, but was considerably higher than the current EU and WHO standards. Heavy metals accumulation in vegetables tested are higher at market sites than those at the crop production sites. The contributions of these vegetables to dietary intake of Cu, Zn, Cd and Pb were 13%, 1%, 47% and 9% of provisional tolerable daily intake, respectively. The study concludes that the transportation and marketing systems of vegetables play a significant role in elevating the contaminant levels of heavy metals which may pose a threat to the quality of the vegetables with consequences for the health of the consumers of locally produced foodstuffs.

Urban heat island and bioclimatological conditions in a hot-humid tropical city: the example of Akure, Nigeria

Directory of Open Access Journals (Sweden)

Balogun, Ifeoluwa A.

2014-09-01

Full Text Available The impact of weather on human health has become an issue of increased significance in recent times, considering the increasing rate of urbanisation and the much associated heat island phenomenon. This study examines the urbanisation influence on human bioclimatic conditions in Akure, a medium sized hot-humid tropical city in Nigeria, utilising data from measurements at urban and rural sites in the city. Differences in the diurnal, monthly and seasonal variation of human bioclimatic characteristics between both environments were evaluated and tested for statistical significance. Higher frequencies of high temperatures observed in the city centre suggest a significant heat stress and health risk in this hot-humid city.

Soil bio-engineering for risk mitigation and environmental restoration in a humid tropical area

Science.gov (United States)

Petrone, A.; Preti, F.

2009-07-01

The use of soil bio-engineering techniques in developing countries is a relevant issue for disaster mitigation, environmental restoration and poverty reduction. Research on authochtonal plants suitable for this kind of works and on economic efficiency is essential for the divulgation of such techniques. The present paper is focused on this two issues related to the realization of various typologies of soil bio-engineering works in the humid tropic of Nicaragua. In the area of Río Blanco, located in the Department of Matagalpa, soil bio-engineering installations were built in several sites. The particular structures built were: drainages with live fascine mattress, a live palisade, a vegetated live crib wall for riverbank protection, a vegetative covering made of a metallic net and biotextile coupled with a live palisade made of bamboo. In order to evaluate the suitability of the various plants used in the works, monitorings were performed, one in the live palisade alongside an unpaved road and the other on the live crib wall along a riverbank, collecting survival rate and morphological parameters data. Concerning the economic efficiency we proceed to a financial analysis of the works and once the unit price was obtained, we converted the amount in EPP Dollars (Equal Purchasing Power) in order to compare the Nicaraguan context with the Italian one. Among the used species we found that Madero negro (Gliricidia sepium) and Roble macuelizo (Tabebuia rosea) are adequate for soil-bioengineering measure on slopes while Helequeme (Erythrina fusca) reported a successful behaviour only in the crib wall for riverbank protection. In the comparison of the costs in Nicaragua and in Italy, the unit price reduction for the Central American country ranges between 1.5 times (for the vegetative covering) and almost 4 times (for the fascine mattress) if it's used the EPP dollar exchange rate. Conclusions are reached with regard to hydrological-risk mitigating actions performed on a

A west-east vegetation transect through Africa south of the Tropic of Capricorn

Directory of Open Access Journals (Sweden)

B. J. Coetzee

1975-11-01

Full Text Available Changes in predominant vegetation physiognomy, prominent species and physiography along the route following an I 800 km transect across southern Africa near the Tropic of Capricorn, are described. Eleven main discontinuities in the structure and Holistic composition of the vegetation along the transect are related to a climatic gradient across the Continent. Floristic variation within the main structural types is largely related to rainfall, severity of frost, soil conditions, exposure, slope and aspect. The main vegetation classes distinguished coincide largely with major differences in carrying capacity of the vegetation.

N2O emissions from humid tropical agricultural soils: effects of soil moisture, texture and nitrogen availability

Science.gov (United States)

A.M. Weitza; E. Linderb; S. Frolkingc; P.M. Crillc; M. Keller

2001-01-01

We studied soil moisture dynamics and nitrous oxide (N2O) ¯uxes from agricultural soils in the humid tropics of Costa Rica. Using a splitplot design on two soils (clay, loam) we compared two crop types (annual, perennial) each unfertilized and fertilized. Both soils are of andic origin. Their properties include relatively low bulk density and high organic matter...

Soil bioengineering for risk mitigation and environmental restoration in a humid tropical area

Directory of Open Access Journals (Sweden)

A. Petrone

2010-02-01

Full Text Available The use of soil bio-engineering techniques in developing countries is a relevant issue for disaster mitigation, environmental restoration and poverty reduction. Research on the autochthonal plants suitable for these kinds of interventions and on the economic efficiency of the interventions is essential for the dissemination of such techniques. The present paper is focused on these two issues as related to the realization of various typologies of soil bioengineering works in the humid tropics of Nicaragua.

In the area of Río Blanco, located in the Department of Matagalpa, soil bioengineering installations were built in several sites. The particular structures built were: drainages with live fascine mattress, a live palisade, a vegetated live crib wall for riverbank protection, a vegetative covering made of a metallic net and biotextile coupled with a live palisade made of bamboo. In order to evaluate the suitability of the various plants used in these works, monitoring was performed, one on the live palisade alongside an unpaved road and the other on the live crib wall along a riverbank, by collecting data on survival rate and morphological parameters. Concerning economic efficiency, we proceeded to a financial analysis of the works. Once the unit price was obtained, we converted the amount into EPP Dollars (Equal Purchasing Power in order to compare the Nicaraguan context with the European one.

Among the species used we found that Gliricidia sepium (local common name: Madero negro and Tabebuia rosea (local common name: Roble macuelizo are adequate for soil bioengineering measures on slopes, while Erythrina fusca (local common name: Helequeme resulted in successful behaviour only in the crib wall for riverbank protection.

In comparing costs in Nicaragua and in Italy, the unit price reduction for Nicaragua ranges from 1.5 times (for the vegetative covering to almost 4 times (for the fascine mattress

Seasonal changes in water content and turnover in cattle, sheep and goats grazing under humid tropical conditions in Ghana

International Nuclear Information System (INIS)

Aggrey, E.K.

1982-01-01

The effect of seasonal changes on water content and water turnover of cattle, sheep and goats at pasture under humid tropical conditions was studied. Measurement of total body water and water turnover was based on the tritium dilution technique. Total body water was significantly higher in all three species of animal during the dry season, while water turnover was significantly lower in the dry season than in the wet season. In all seasons water turnover was highest in cattle, followed by sheep and then goat. Changes in body weight, body water, body solids and water turnover were associated with seasonal variations in nutrition. The indication was that the goat would be a more suitable animal for production under dry conditions than cattle and sheep. (author)

High relative humidity in-package of fresh-cut fruits and vegetables: advantage or disadvantage considering microbiological problems and antimicrobial delivering systems?

Science.gov (United States)

Ayala-Zavala, J F; Del-Toro-Sánchez, L; Alvarez-Parrilla, E; González-Aguilar, G A

2008-05-01

This hypothesis article states that the high relative humidity (RH) of packaged fresh-cut fruits or vegetables that is associated with spoilage can be used as an advantageous way to deliver antimicrobial compounds using cyclodextrins (CDs) as carriers. CDs can function as antimicrobial delivery systems as they can release antioxidant and antimicrobial compounds (guest molecules) as the humidity levels increase in the headspace. Hydrophobic antimicrobial guests can be complexed with CDs due to the amphiphatic nature of the host. Then, at high RH values, due to the water-CDs interaction, host-guest interactions are weakened; consequently, the antimicrobial molecule is released and should protect the product against the microbial growth. Potential antimicrobial compounds capable of forming complexes with CDs are discussed, as well as possible applications to preserve fresh-cut produce and future research in this area.

Radio-frequency dielectric properties of some tropical African leaf vegetables

International Nuclear Information System (INIS)

Laogun, A.A.; Ajayi, N.O.

1985-03-01

The variation of the relative permittivity epsilon'sub(r), the loss factor epsilon'' and a.c. conductivity σ with the frequency of an applied electromagnetic field over the range 0.5 to 50 MHz has been studied in the leaf and stem tissues of three tropical vegetables viz - amaranthus, bitter leaf and okra. This is with a view to investigate the molecular structure and dielectric heating characteristics of the leaves and stems in the different vegetables considered. The Cole-Cole plots of the data showed that in all cases, both the stems and leaves exhibited a spread of relaxation times, indicating heterogeneity of structure. In general, the a.c. conductivity and the dielectric energy loss factor also appear to be much larger in the vegetable stems than in the leaves, suggesting that energy dissipation in stems is greater than in the leaves. (author)

Modelling the Congo basin ecosystems with a dynamic vegetation model

Science.gov (United States)

Dury, Marie; Hambuckers, Alain; Trolliet, Franck; Huynen, Marie-Claude; Haineaux, Damien; Fontaine, Corentin M.; Fayolle, Adeline; François, Louis

2014-05-01

The scarcity of field observations in some parts of the world makes difficult a deep understanding of some ecosystems such as humid tropical forests in Central Africa. Therefore, modelling tools are interesting alternatives to study those regions even if the lack of data often prevents sharp calibration and validation of the model projections. Dynamic vegetation models (DVMs) are process-based models that simulate shifts in potential vegetation and its associated biogeochemical and hydrological cycles in response to climate. Initially run at the global scale, DVMs can be run at any spatial scale provided that climate and soil data are available. In the framework of the BIOSERF project ("Sustainability of tropical forest biodiversity and services under climate and human pressure"), we use and adapt the CARAIB dynamic vegetation model (Dury et al., iForest - Biogeosciences and Forestry, 4:82-99, 2011) to study the Congo basin vegetation dynamics. The field campaigns have notably allowed the refinement of the vegetation representation from plant functional types (PFTs) to individual species through the collection of parameters such as the specific leaf area or the leaf C:N ratio of common tropical tree species and the location of their present-day occurrences from literature and available database. Here, we test the model ability to reproduce the present spatial and temporal variations of carbon stocks (e.g. biomass, soil carbon) and fluxes (e.g. gross and net primary productivities (GPP and NPP), net ecosystem production (NEP)) as well as the observed distribution of the studied species over the Congo basin. In the lack of abundant and long-term measurements, we compare model results with time series of remote sensing products (e.g. vegetation leaf area index (LAI), GPP and NPP). Several sensitivity tests are presented: we assess consecutively the impacts of the level at which the vegetation is simulated (PFTs or species), the spatial resolution and the initial land

Factors influencing storm-generated suspended-sediment concentrations and loads in four basins of contrasting land use, humid-tropical Puerto Rico

Science.gov (United States)

A. C. Gellis; NO-VALUE

2013-01-01

The significant characteristics controlling the variability in storm-generated suspended-sediment loads and concentrations were analyzed for four basins of differing land use (forest, pasture, cropland, and urbanizing) in humid-tropical Puerto Rico. Statistical analysis involved stepwise regression on factor scores. The explanatory variables were attributes of flow,...

Identifying N fertilizer regime and vegetable production system in tropical Brazil using (15) N natural abundance.

Science.gov (United States)

Inácio, Caio T; Urquiaga, Segundo; Chalk, Phillip M; Mata, Maria Gabriela F; Souza, Paulo O

2015-12-01

This study was conducted in areas of vegetable production in tropical Brazil, with the objectives of (i) measuring the variation in δ(15)  N in soils, organic N fertilizer sources and lettuce (Lactuca sativa L.) from different farming systems, (ii) measuring whether plant δ(15)  N can differentiate organic versus conventional lettuce and (iii) identifying the factors affecting lettuce δ(15)  N. Samples of soil, lettuce and organic inputs were taken from two organic, one conventional and one hydroponic farm. The two organic farms had different N-sources with δ(15)  N values ranging from 0.0 to +14.9‰ (e.g. leguminous green manure and animal manure compost, respectively), and differed significantly (P hydroponic lettuce δ(15)  N (+4.5 ± 0.2‰) due to manure inputs. The N from leguminous green manure made a small contribution to the N nutrition of lettuce in the multi-N-source organic farm. To differentiate organic versus conventional farms using δ(15)  N the several subsets of mode of fertilization should be considered. Comparisons of δ(15)  N of soil, organic inputs and lettuce allowed a qualitative analysis of the relative importance of different N inputs. © 2015 Society of Chemical Industry.

Vegetation-climate feedback causes reduced precipitation and tropical rainforest cover in CMIP5 regional Earth system model simulation over Africa

Science.gov (United States)

Wu, M.; Smith, B.; Samuelsson, P.; Rummukainen, M.; Schurgers, G.

2012-12-01

We applied a coupled regional climate-vegetation model, RCA-GUESS (Smith et al. 2011), over the CORDEX Africa domain, forced by boundary conditions from a CanESM2 CMIP5 simulation under the RCP8.5 future climate scenario. The simulations were from 1961 to 2100 and covered the African continent at a horizontal grid spacing of 0.44°. RCA-GUESS simulates changes in the phenology, productivity, relative cover and population structure of up to eight plant function types (PFTs) in response to forcing from the climate part of the model. These vegetation changes feed back to simulated climate through dynamic adjustments in surface energy fluxes and surface properties. Changes in the net ecosystem-atmosphere carbon flux and its components net primary production (NPP), heterotrophic respiration and emissions from biomass burning were also simulated but do not feed back to climate in our model. Constant land cover was assumed. We compared simulations with and without vegetation feedback switched "on" to assess the influence of vegetation-climate feedback on simulated climate, vegetation and ecosystem carbon cycling. Both positive and negative warming feedbacks were identified in different parts of Africa. In the Sahel savannah zone near 15°N, reduced vegetation cover and productivity, and mortality caused by a deterioration of soil water conditions led to a positive warming feedback mediated by decreased evapotranspiration and increased sensible heat flux between vegetation and the atmosphere. In the equatorial rainforest stronghold region of central Africa, a feedback syndrome characterised by reduced plant production and LAI, a dominance shift from tropical trees to grasses, reduced soil water and reduced rainfall was identified. The likely underlying mechanism was a decline in evaporative water recycling associated with sparser vegetation cover, reminiscent of Earth system model studies in which a similar feedback mechanism was simulated to force dieback of tropical

Evaporative cooling system for storage of fruits and vegetables - a review.

Science.gov (United States)

Lal Basediya, Amrat; Samuel, D V K; Beera, Vimala

2013-06-01

Horticultural produce are stored at lower temperature because of their highly perishable nature. There are many methods to cool the environment. Hence, preserving these types of foods in their fresh form demands that the chemical, bio-chemical and physiological changes are restricted to a minimum by close control of space temperature and humidity. The high cost involved in developing cold storage or controlled atmosphere storage is a pressing problem in several developing countries. Evaporative cooling is a well-known system to be an efficient and economical means for reducing the temperature and increasing the relative humidity in an enclosure and this effect has been extensively tried for increasing the shelf life of horticultural produce in some tropical and subtropical countries. In this review paper, basic concept and principle, methods of evaporative cooling and their application for the preservation of fruits and vegetables and economy are also reported. Thus, the evaporative cooler has prospect for use for short term preservation of vegetables and fruits soon after harvest. Zero energy cooling system could be used effectively for short-duration storage of fruits and vegetables even in hilly region. It not only reduces the storage temperature but also increases the relative humidity of the storage which is essential for maintaining the freshness of the commodities.

Climate and vegetational regime shifts in the late Paleozoic ice age earth.

Science.gov (United States)

DiMichele, W A; Montañez, I P; Poulsen, C J; Tabor, N J

2009-03-01

The late Paleozoic earth experienced alternation between glacial and non-glacial climates at multiple temporal scales, accompanied by atmospheric CO2 fluctuations and global warming intervals, often attended by significant vegetational changes in equatorial latitudes of Pangaea. We assess the nature of climate-vegetation interaction during two time intervals: middle-late Pennsylvanian transition and Pennsylvanian-Permian transition, each marked by tropical warming and drying. In case study 1, there is a catastrophic intra-biomic reorganization of dominance and diversity in wetland, evergreen vegetation growing under humid climates. This represents a threshold-type change, possibly a regime shift to an alternative stable state. Case study 2 is an inter-biome dominance change in western and central Pangaea from humid wetland and seasonally dry to semi-arid vegetation. Shifts between these vegetation types had been occurring in Euramerican portions of the equatorial region throughout the late middle and late Pennsylvanian, the drier vegetation reaching persistent dominance by Early Permian. The oscillatory transition between humid and seasonally dry vegetation appears to demonstrate a threshold-like behavior but probably not repeated transitions between alternative stable states. Rather, changes in dominance in lowland equatorial regions were driven by long-term, repetitive climatic oscillations, occurring with increasing intensity, within overall shift to seasonal dryness through time. In neither case study are there clear biotic or abiotic warning signs of looming changes in vegetational composition or geographic distribution, nor is it clear that there are specific, absolute values or rates of environmental change in temperature, rainfall distribution and amount, or atmospheric composition, approach to which might indicate proximity to a terrestrial biotic-change threshold.

Maize Storage in Termite Mound Clay, Concrete, and Steel Silos in the Humid Tropics: Comparison and Effect on Bacterial and Fungal Counts

Science.gov (United States)

This study investigated the functional suitability of using the readily-available termite mound clay (TMC) for grain silo construction in comparison to conventional reinforced concrete (RC) and galvanized steel (GS) silos for maize storage in the humid tropics. The extent to which temperature and r...

Securing tropical forest carbon

DEFF Research Database (Denmark)

Scharlemann, Jörn P. W.; Kapos, Valerie; Campbell, Alison

2010-01-01

Forest loss and degradation in the tropics contribute 6-17% of all greenhouse gas emissions. Protected areas cover 217.2 million ha (19.6%) of the world's humid tropical forests and contain c. 70.3 petagrams of carbon (Pg C) in biomass and soil to 1 m depth. Between 2000 and 2005, we estimate...... that 1.75 million ha of forest were lost from protected areas in humid tropical forests, causing the emission of 0.25-0.33 Pg C. Protected areas lost about half as much carbon as the same area of unprotected forest. We estimate that the reduction of these carbon emissions from ongoing deforestation...... in protected sites in humid tropical forests could be valued at USD 6,200-7,400 million depending on the land use after clearance. This is >1.5 times the estimated spending on protected area management in these regions. Improving management of protected areas to retain forest cover better may be an important...

An Embedded Sensor Network for Measuring Elevation Effects on Temperature, Humidity, and Evapotranspiration Within a Tropical Alpine Valley

Science.gov (United States)

Hellstrom, R. A.; Mark, B. G.

2006-12-01

Conditions of glacier recession in the seasonally dry tropical Peruvian Andes motivates research to better constrain the hydrological balance in alpine valleys. Studies suggest that glaciers in the tropical Andes are particularly sensitive to seasonal humidity flux due to the migration of the Intertropical Convergence Zone. However, there is an outstanding need to better measure and model the spatiotemporal variability of energy and water budgets within pro-glacial valleys. In this context, we introduce a novel embedded network of low- cost, discrete temperature and humidity microloggers and an automatic weather station installed in the Llanganuco valley of the Cordillera Blanca. This paper presents data recorded over a full annual cycle (2004- 2005) and reports on network design and results during the dry and wet seasons. The transect of sensors ranging from about 3500 to 4700 m reveal seasonally characteristic diurnal fluctuations in up-valley lapse rate. A process-based water balance model (Brook90) examines the influence of meteorological forcing on evapotranspiration (ET) rates in the valley. The model results suggest that cloud-free daylight conditions enhances ET during the wet season. ET was insignificant throughout the dry season. In addition, we report on the effects of elevation on ET.

Estimating productivity of tropical forest plantations by climatic factors

Energy Technology Data Exchange (ETDEWEB)

Pandey, D.

1996-12-31

This study presents an alternative method of estimating wood production at regional/global levels from tropical plantations based on climatic variables. A generic model for estimating potential yield in tropical plantations was formulated. The model was developed for teak (Tectona grandis L. F.) as a case study. Available data of teak sample plots from India, Myanmar, Indonesia, Nigeria and Ivory Coast, consisting of 153 plots distributed over 38 meteorological stations were used. A new base age invariant site index function was developed and the site index of each plot was estimated. The mean annual volume increment (MAI) of each plot from existing yield tables was then interpolated. Treating MAI at 50 years (rotation age) as potential yield of teak, a model was constructed which could explain about 59% variance of the potential yield. Models constructed for estimating the maximum MAI and the site index of teak explained the variability up to 61% and 57% respectively. The models underestimated the productivity of teak in Indonesia, Nigeria and Ivory Coast. The rainfall and the relative humidity have been identified as the most important climatic variables influencing the growth of teak. The length of the growing season and the temperature of the warmest month of the growing season were found significant in the models. The temperature and the day length (sunshine) have not been found to be the limiting factors for the growth of teak. However, the maximum temperature beyond a certain upper limit has a negative effect on growth. The study indicates that this upper limit is around 33 deg C for teak. The models could be used to forecast the potential yield of the existing as well as planned teak plantations in the tropical region. 109 refs, 15 figs, 11 tabs

Humidity level In psychrometric processes

International Nuclear Information System (INIS)

Mojsovski, Filip

2008-01-01

When a thermal engineer needs to control, rather than merely moderate humidity, he must focus on the moisture level as a separate variable - not simply an addition of temperature control. Controlling humidity generally demands a correct psychrometric approach dedicated to that purpose [1].Analysis of the humidity level in psychrometric thermal processes leads to relevant data for theory and practice [2]. This paper presents: (1) the summer climatic curve for the Skopje region, (2) selected results of investigation on farm dryers made outside laboratories. The first purpose of such activity was to examine relations between weather conditions and drying conditions. The estimation of weather condition for the warmest season of the year was realized by a summer climatic curve. In the science of drying, basic drying conditions are temperature, relative humidity and velocity of air, thickness of dried product and dryer construction. The second purpose was to realize correct prediction of drying rates for various psychrometrics drying processes and local products. Test runs with the dryer were carried out over a period of 24 h, using fruits and vegetables as experimental material. Air flow rate through the dryer of 150 m3/h, overall drying rate of 0.04 kg/h and air temperature of 65 oC were reached. Three types of solar dryers, were exploited in the research.

Advancing the quantification of humid tropical forest cover loss with multi-resolution optical remote sensing data: Sampling & wall-to-wall mapping

Science.gov (United States)

Broich, Mark

Humid tropical forest cover loss is threatening the sustainability of ecosystem goods and services as vast forest areas are rapidly cleared for industrial scale agriculture and tree plantations. Despite the importance of humid tropical forest in the provision of ecosystem services and economic development opportunities, the spatial and temporal distribution of forest cover loss across large areas is not well quantified. Here I improve the quantification of humid tropical forest cover loss using two remote sensing-based methods: sampling and wall-to-wall mapping. In all of the presented studies, the integration of coarse spatial, high temporal resolution data with moderate spatial, low temporal resolution data enable advances in quantifying forest cover loss in the humid tropics. Imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) are used as the source of coarse spatial resolution, high temporal resolution data and imagery from the Landsat Enhanced Thematic Mapper Plus (ETM+) sensor are used as the source of moderate spatial, low temporal resolution data. In a first study, I compare the precision of different sampling designs for the Brazilian Amazon using the annual deforestation maps derived by the Brazilian Space Agency for reference. I show that sampling designs can provide reliable deforestation estimates; furthermore, sampling designs guided by MODIS data can provide more efficient estimates than the systematic design used for the United Nations Food and Agricultural Organization Forest Resource Assessment 2010. Sampling approaches, such as the one demonstrated, are viable in regions where data limitations, such as cloud contamination, limit exhaustive mapping methods. Cloud-contaminated regions experiencing high rates of change include Insular Southeast Asia, specifically Indonesia and Malaysia. Due to persistent cloud cover, forest cover loss in Indonesia has only been mapped at a 5-10 year interval using photo interpretation of single

Submerged Humid Tropical Karst Landforms Observed By High-Resolution Multibeam Survey in Nagura Bay, Ishigaki Island, Southwestern Japan

Science.gov (United States)

Kan, H.; Urata, K.; Nagao, M.; Hori, N.; Fujita, K.; Yokoyama, Y.; Nakashima, Y.; Ohashi, T.; Goto, K.; Suzuki, A.

2014-12-01

Submerged tropical karst features were discovered in Nagura Bay on Ishigaki Island in the South Ryukyu Islands, Japan. This is the first description of submerged humid tropical karst using multibeam bathymetry. We conducted a broadband multibeam survey in the central area of Nagura Bay (1.85 × 2.7 km) and visualized the high-resolution bathymetric results with a grid size of 1 m over a depth range of 1.6-58.5 m. Various types of humid tropical karst landforms were found to coexist within the bay, including fluviokarst, doline karst, cockpit karst, polygonal karst, uvalas, and mega-dolines. We assume that Nagura Bay was a large karst basin in which older limestone remained submerged, thus preventing corrosion and the accumulation of reef sediments during periods of submersion, whereas the limestone outcropping on land was corroded during multiple interglacial and glacial periods. Based on our bathymetric result together with aerial photographs of the coastal area, we conclude that the submerged karst landscape has likely developed throughout the whole of Nagura Bay, covering an area of ~6 × 5 km. Accordingly, this area hosts the largest submerged karst in Japan. We also observed abundant coral communities during our SCUBA observations. The present marine conditions of Nagura Bay are characterized by low energy (calm sea) and low irradiance owing to the terrestrial influence. Such conditions have been emphasized by the presence of large undulating landforms, which cause decreases in wave intensity and irradiance with depth. These characteristics have acted to establish unique conditions compared to other coral reef areas in the Ryukyu Islands. It may play an important role in supporting the regional coral reef ecosystem.

Lability of soil organic carbon in tropical soils with different clay minerals

DEFF Research Database (Denmark)

Bruun, Thilde Bech; Elberling, Bo; Christensen, Bent Tolstrup

2010-01-01

Soil organic carbon (SOC) storage and turnover is influenced by interactions between organic matter and the mineral soil fraction. However, the influence of clay content and type on SOC turnover rates remains unclear, particularly in tropical soils under natural vegetation. We examined the lability...... of SOC in tropical soils with contrasting clay mineralogy (kaolinite, smectite, allophane and Al-rich chlorite). Soil was sampled from A horizons at six sites in humid tropical areas of Ghana, Malaysian Borneo and the Solomon Islands and separated into fractions above and below 250 µm by wet sieving....... Basal soil respiration rates were determined from bulk soils and soil fractions. Substrate induced respiration rates were determined from soil fractions. SOC lability was significantly influenced by clay mineralogy, but not by clay content when compared across contrasting clay minerals. The lability...

The ameliorative effect of ascorbic acid on the oxidative status, live weight and recovery rate in road transport stressed goats in a hot humid tropical environment.

Science.gov (United States)

Nwunuji, Tanko Polycarp; Mayowa, Opeyemi Onilude; Yusoff, Sabri Mohd; Bejo, Siti-Khairani; Salisi, Shahrom; Mohd, Effendy Abd Wahid

2014-05-01

The ameliorative effect of ascorbic acid (AA) on live weight following transportation is vital in animal husbandry. This study investigated the influence of AA on live weight, rectal temperature (rt), and oxidative status of transport stressed goats in a hot humid tropical environment. Twenty-four goats were divided into four groups, A, B, C and D of six animals each. Group A were administered AA 100 mg/kg intramuscularly 30 min prior to 3.5 h transportation. Group B was administered AA following transportation. Group C were transported but not administered AA as positive controls while group D were not transported but were administered normal saline as negative controls. Live weight, rt and blood samples were collected before, immediately post-transport (pt), 24 h, 3 days, 7 days and 10 days pt. Plasma was used for malondialdehyde (MDA) analysis while hemolysates were used for superoxide dismutase (SOD) analysis. There was minimal live weight loss in group A compared to groups B and C. Group A recorded reduced MDA activities and increased SOD activities compared to groups B and C which recorded significantly high MDA activities. This study revealed that AA administration ameliorated the stress responses induced by transportation in animals in hot humid tropical environments. The administration of AA to goats prior to transportation could ameliorate stress and enhance productivity. © 2014 Japanese Society of Animal Science.

The role of vegetation in the CO2 flux from a tropical urban neighbourhood

Science.gov (United States)

Velasco, E.; Roth, M.; Tan, S. H.; Quak, M.; Nabarro, S. D. A.; Norford, L.

2013-03-01

Urban surfaces are usually net sources of CO2. Vegetation can potentially have an important role in reducing the CO2 emitted by anthropogenic activities in cities, particularly when vegetation is extensive and/or evergreen. Negative daytime CO2 fluxes, for example have been observed during the growing season at suburban sites characterized by abundant vegetation and low population density. A direct and accurate estimation of carbon uptake by urban vegetation is difficult due to the particular characteristics of the urban ecosystem and high variability in tree distribution and species. Here, we investigate the role of urban vegetation in the CO2 flux from a residential neighbourhood in Singapore using two different approaches. CO2 fluxes measured directly by eddy covariance are compared with emissions estimated from emissions factors and activity data. The latter includes contributions from vehicular traffic, household combustion, soil respiration and human breathing. The difference between estimated emissions and measured fluxes should approximate the biogenic flux. In addition, a tree survey was conducted to estimate the annual CO2 sequestration using allometric equations and an alternative model of the metabolic theory of ecology for tropical forests. Palm trees, banana plants and turfgrass were also included in the survey with their annual CO2 uptake obtained from published growth rates. Both approaches agree within 2% and suggest that vegetation captures 8% of the total emitted CO2 in the residential neighbourhood studied. A net uptake of 1.4 ton km-2 day-1 (510 ton km-2 yr-1 ) was estimated from the difference between the daily CO2 uptake by photosynthesis (3.95 ton km-2 ) and release by respiration (2.55 ton km-2). The study shows the importance of urban vegetation at the local scale for climate change mitigation in the tropics.

Long-term CO2 fertilization increases vegetation productivity and has little effect on hydrological partitioning in tropical rainforests

Science.gov (United States)

Yang, Yuting; Donohue, Randall J.; McVicar, Tim R.; Roderick, Michael L.; Beck, Hylke E.

2016-08-01

Understanding how tropical rainforests respond to elevated atmospheric CO2 concentration (eCO2) is essential for predicting Earth's carbon, water, and energy budgets under future climate change. Here we use long-term (1982-2010) precipitation (P) and runoff (Q) measurements to infer runoff coefficient (Q/P) and evapotranspiration (E) trends across 18 unimpaired tropical rainforest catchments. We complement that analysis by using satellite observations coupled with ecosystem process modeling (using both "top-down" and "bottom-up" perspectives) to examine trends in carbon uptake and relate that to the observed changes in Q/P and E. Our results show there have been only minor changes in the satellite-observed canopy leaf area over 1982-2010, suggesting that eCO2 has not increased vegetation leaf area in tropical rainforests and therefore any plant response to eCO2 occurs at the leaf level. Meanwhile, observed Q/P and E also remained relatively constant in the 18 catchments, implying an unchanged hydrological partitioning and thus approximately conserved transpiration under eCO2. For the same period, using a top-down model based on gas exchange theory, we predict increases in plant assimilation (A) and light use efficiency (ɛ) at the leaf level under eCO2, the magnitude of which is essentially that of eCO2 (i.e., 12% over 1982-2010). Simulations from 10 state-of-the-art bottom-up ecosystem models over the same catchments also show that the direct effect of eCO2 is to mostly increase A and ɛ with little impact on E. Our findings add to the current limited pool of knowledge regarding the long-term eCO2 impacts in tropical rainforests.

La culture de l'amarante, légume-feuilles tropical : avec référence spéciale au sud-Dahomey

NARCIS (Netherlands)

Grubben, G.J.H.

1975-01-01

1. INTRODUCTION

Amaranth is the most cultivated leaf vegetable of the humid tropics and as such comparable to spinach in the temperate regions. Efforts to improve the crop are hampered by a shortage of knowledge. The object of this study is to fill up a part of this gap. The

Performance evaluation of an indirect pre-cooling evaporative heat exchanger operating in hot and humid climate

International Nuclear Information System (INIS)

Cui, X.; Chua, K.J.; Islam, M.R.; Ng, K.C.

2015-01-01

Highlights: • An IEHX is introduced as a pre-cooling unit for humid tropical climate. • A computational model is developed to investigate the performance of IEHX. • The air treatment process with condensation from the product air is studied. • The hybrid system shows an appreciable energy saving potential. - Abstract: A hybrid system, that combines an indirect evaporative heat exchanger (IEHX) and a vapor compression system, is introduced for humid tropical climate application. The chief purpose of the IEHX is to pre-cool the incoming air for vapor compression system. In the IEHX unit, the outdoor humid air in the product channel may potentially condense when heat is exchanged with the room exhaust air. A computational model has been developed to theoretically investigate the performance of an IEHX with condensation from the product air by employing the room exhaust air as the working air. We validated the model by comparing its temperature distribution and predicted heat flux against experimental data acquired from literature sources. The numerical model showed good agreement with the experimental findings with maximum average discrepancy of 9.7%. The validated model was employed to investigate the performance of two types of IEHX in terms of the air treatment process, temperature and humidity distribution, cooling effectiveness, cooling capacity, and energy consumption. Simulation results have indicated that the IEHX unit is able to fulfill 47% of the cooling load for the outdoor humid air while incurring a small amount of fan power. Consequently, the hybrid system is able to realize significant energy savings

Benthic macrofaunal structure and secondary production in tropical estuaries on the Eastern Marine Ecoregion of Brazil.

Science.gov (United States)

Bissoli, Lorena B; Bernardino, Angelo F

2018-01-01

Tropical estuaries are highly productive and support diverse benthic assemblages within mangroves and tidal flats habitats. Determining differences and similarities of benthic assemblages within estuarine habitats and between regional ecosystems may provide scientific support for management of those ecosystems. Here we studied three tropical estuaries in the Eastern Marine Ecoregion of Brazil to assess the spatial variability of benthic assemblages from vegetated (mangroves) and unvegetated (tidal flats) habitats. A nested sampling design was used to determine spatial scales of variability in benthic macrofaunal density, biomass and secondary production. Habitat differences in benthic assemblage composition were evident, with mangrove forests being dominated by annelids (Oligochaeta and Capitellidae) whereas peracarid crustaceans were also abundant on tidal flats. Macrofaunal biomass, density and secondary production also differed between habitats and among estuaries. Those differences were related both to the composition of benthic assemblages and to random spatial variability, underscoring the importance of hierarchical sampling in estuarine ecological studies. Given variable levels of human impacts and predicted climate change effects on tropical estuarine assemblages in Eastern Brazil, our data support the use of benthic secondary production to address long-term changes and improved management of estuaries in Eastern Brazil.

Hydrological Networks and Associated Topographic Variation as Templates for the Spatial Organization of Tropical Forest Vegetation

OpenAIRE

Detto, Matteo; Muller-Landau, Helene C.; Mascaro, Joseph; Asner, Gregory P.

2013-01-01

An understanding of the spatial variability in tropical forest structure and biomass, and the mechanisms that underpin this variability, is critical for designing, interpreting, and upscaling field studies for regional carbon inventories. We investigated the spatial structure of tropical forest vegetation and its relationship to the hydrological network and associated topographic structure across spatial scales of 10-1000 m using high-resolution maps of LiDAR-derived mean canopy profile heigh...

Potential role of vegetation dynamics on recent extreme droughts over tropical South America

Science.gov (United States)

Wang, G.; Erfanian, A.; Fomenko, L.

2017-12-01

Tropical South America is a drought hot spot. In slightly over a decade (2005-2016), the region encountered three extreme droughts (2005, 2010, and 2016). Recurrent extreme droughts not only impact the region's eco-hydrology and socio-economy, but are also globally important as they can transform the planet's largest rainforest, the Amazon, from a carbon sink to a carbon source. Understanding drought drivers and mechanisms underlying extreme droughts in tropical South America can help better project the fate of the Amazon rainforest in a changing climate. In this study we use a regional climate model (RegCM4.3.4) coupled with a comprehensive land-surface model (CLM4.5) to study the present-day hydroclimate of the region, focusing specifically on what might have caused the frequent recurrence of extreme droughts. In the context of observation natural variability of the global oceanic forcing, we tackle the role of land-atmosphere interactions and ran the model with and without dynamic vegetation to study how vegetation dynamics and carbon-nitrogen cycles may have influenced the drought characteristics. Our results demonstrate skillful simulation of the South American climate in the model, and indicate substantial sensitivity of the region's hydroclimatology to vegetation dynamics. This presentation will compare the role of global oceanic forcing versus regional land surface feedback in the recent recurrent droughts, and will characterize the effects of vegetation dynamics in enhancing the drought severity. Preliminary results on future projections of the regional ecosystem and droughts perspective will be also presented.

Vegetable Production System (Veggie)

Data.gov (United States)

National Aeronautics and Space Administration — The Vegetable Production System (Veggie) was developed to be a simple, easily stowed, high growth volume, low resource facility capable of producing fresh vegetables...

Germination of tropical forage seeds stored for six years in ambient and controlled temperature and humidity conditions in Thailand

Directory of Open Access Journals (Sweden)

Michael D. Hare

2018-01-01

Full Text Available The germination performances of fresh seed lots were determined for 5 tropical forage species: Mulato II hybrid brachiaria [Urochloa ruziziensis (syn. Brachiaria ruziziensis x U. decumbens (syn. B. decumbens x U. brizantha (syn. B. brizantha], Mombasa guinea [Megathyrsus maximus (syn. Panicum maximum], Tanzania guinea [M. maximus (syn. P. maximum], Ubon paspalum (Paspalum atratum and Ubon stylo (Stylosanthes guianensis, stored under ambient conditions in Thailand (mean monthly temperatures 23‒34 ºC; mean monthly relative humidity 40‒92% or in a cool room (18‒20 ºC and 50% relative humidity for up to 6 years. The first paper of this study showed all seeds, except unscarified Ubon stylo seed, were dead after a single year of storage in ambient conditions. This second paper shows that cool-room storage extended seed viability, but performance varied considerably between species. Germination percentage under laboratory conditions declined to below 50%, after 3 years storage for Mombasa guinea seed and Tanzania guinea seed, 4 years for Ubon paspalum seed and 4‒5 years for Mulato II seed. Ubon stylo seed maintained high germination for 5 years, in both cool-room storage (96% and ambient-room storage (84%. Apparent embryo dormancy in acid-scarified Mulato II seed steadily increased with time in cool-storage and this seed had to be acid-scarified again each year at the time of germination testing to overcome dormancy. Physical dormancy of Mulato II seeds, imposed by the tightly bound lemma and palea in unscarified seed, was not overcome by length of time in cool-storage and these seeds had to be acid-scarified to induce germination. Hardseeded percentage in Ubon stylo seed remained high throughout the study and could be overcome only by acid-scarification. The difficulties of maintaining acceptable seed germination percentages when storing forage seeds in the humid tropics are discussed.

Deadwood biomass: an underestimated carbon stock in degraded tropical forests?

Science.gov (United States)

Pfeifer, Marion; Lefebvre, Veronique; Turner, Edgar; Cusack, Jeremy; Khoo, MinSheng; Chey, Vun K.; Peni, Maria; Ewers, Robert M.

2015-04-01

Despite a large increase in the area of selectively logged tropical forest worldwide, the carbon stored in deadwood across a tropical forest degradation gradient at the landscape scale remains poorly documented. Many carbon stock studies have either focused exclusively on live standing biomass or have been carried out in primary forests that are unaffected by logging, despite the fact that coarse woody debris (deadwood with ≥10 cm diameter) can contain significant portions of a forest’s carbon stock. We used a field-based assessment to quantify how the relative contribution of deadwood to total above-ground carbon stock changes across a disturbance gradient, from unlogged old-growth forest to severely degraded twice-logged forest, to oil palm plantation. We measured in 193 vegetation plots (25 × 25 m), equating to a survey area of >12 ha of tropical humid forest located within the Stability of Altered Forest Ecosystems Project area, in Sabah, Malaysia. Our results indicate that significant amounts of carbon are stored in deadwood across forest stands. Live tree carbon storage decreased exponentially with increasing forest degradation 7-10 years after logging while deadwood accounted for >50% of above-ground carbon stocks in salvage-logged forest stands, more than twice the proportion commonly assumed in the literature. This carbon will be released as decomposition proceeds. Given the high rates of deforestation and degradation presently occurring in Southeast Asia, our findings have important implications for the calculation of current carbon stocks and sources as a result of human-modification of tropical forests. Assuming similar patterns are prevalent throughout the tropics, our data may indicate a significant global challenge to calculating global carbon fluxes, as selectively-logged forests now represent more than one third of all standing tropical humid forests worldwide.

Temperature and Humidity Effects on Hospital Morbidity in Darwin, Australia.

Science.gov (United States)

Goldie, James; Sherwood, Steven C; Green, Donna; Alexander, Lisa

2015-01-01

Many studies have explored the relationship between temperature and health in the context of a changing climate, but few have considered the effects of humidity, particularly in tropical locations, on human health and well-being. To investigate this potential relationship, this study assessed the main and interacting effects of daily temperature and humidity on hospital admission rates for selected heat-relevant diagnoses in Darwin, Australia. Univariate and bivariate Poisson generalized linear models were used to find statistically significant predictors and the admission rates within bins of predictors were compared to explore nonlinear effects. The analysis indicated that nighttime humidity was the most statistically significant predictor (P < 0.001), followed by daytime temperature and average daily humidity (P < 0.05). There was no evidence of a significant interaction between them or other predictors. The nighttime humidity effect appeared to be strongly nonlinear: Hot days appeared to have higher admission rates when they were preceded by high nighttime humidity. From this analysis, we suggest that heat-health policies in tropical regions similar to Darwin need to accommodate the effects of temperature and humidity at different times of day. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Reproductive and productive performances of Santa Inês ewes submitted to breeding in different periods of the Amazonian humid tropical climate.

Science.gov (United States)

Soares, Felipe Nogueira; Oliveira, Maria Emilia Franco; Padilha-Nakaghi, Luciana Cristina; de Oliveira, Luís Guilherme; Feliciano, Marcus Antônio Rossi; de Oliveira, Felipe Brener Bezerra; Teixeira, Pedro Paulo Maia; Vicente, Wilter Ricardo Russiano; Faturi, Cristian; Rodrigues, Luiz Fernando de Souza

2015-12-01

The objective of this study was to evaluate the reproductive and productive performance of Santa Inês ewes bred at different times of the year in humid tropical climate. One hundred and forty-eight Santa Inês ewes were grouped according to the time of the year of their breeding season (i.e., mating period) (dry/wet, wet, wet/dry, and dry season). The service type was natural mating and the ewes and rams were kept together every night for 45 days. Reproductive efficiency was assessed by service, pregnancy, lambing, prolificacy, twinning, pregnancy loss, weaning, and lamb mortality rates. Ewes were weighed at the beginning and at the end of the breeding season and before and after parturition, and sequential weighing of the lambs was performed (at birth, 15, 30, 60, and 90 days). Reproductive efficiency index (number of lambs weaned/total of served ewes) and productive efficiency (kg of weaned lamb/kg of served or lambed ewes) were calculated. All ewes expressed estrus early in the breeding season; however, a higher percentage (53.5 and 7.1 % at 30 and 45 days, respectively) of ewes returned to estrus during the wet/dry period. The lower rates (13.9 %) of return to estrus at 30 days were during the wet season (P  0.05) effects of breeding seasons on the remaining reproductive rates. Ewes that lambed during the wet/dry transition period weighted less, before (40.5 ± 2.5 kg) and after (38.6 ± 1.6 kg) parturition, than those of other groups (P ewes, respectively; P ewes served in the dry season. The reproductive performance of Santa Inês ewes was not significantly influenced by the period of the year in which the breeding seasons took place, allowing for four breeding seasons a year in the Amazon region. Variations between periods in return to estrus rates, weight of ewes close to parturition and lamb weight at weaning indicate that climate changes can also affect reproductive rates.

Cyclic changes in Pennsylvanian paleoclimate and effects on floristic dynamics in tropical Pangaea

Science.gov (United States)

DiMichele, W.A.; Cecil, C.B.; Montanez, I.P.; Falcon-Lang, H. J.

2010-01-01

Wetland floras narrowly define perceptions of Pennsylvanian tropical ecosystems, the so-called Coal Age. Such wetlands reflect humid to perhumid climate, leading to characterizations of Pennsylvanian tropics as everwet, swampy. These views are biased by the high preservation potential of wetlands. Sedimentation patterns, paleosols, and fossil floras indicate the presence of vegetation tolerant of subhumid to dry-subhumid, perhaps semi-arid climate in basins between peat formation times. Understanding the significance of this seasonally-dry vegetation has suffered from conceptual and terminological confusion. A clearer view has emerged as models for framing the data have improved. Basinal floras typical of seasonally-dry conditions, relatively low soil moisture regimes, are well documented but mainly from isolated deposits. Some of the earliest, dominated by primitive pteridosperms ("Fl??zfern" floras), occur in clastic rocks between European Early Pennsylvanian coal beds. Later Early Pennsylvanian, fern-cordaitalean vegetation, different from coal floras, is preserved in marine goniatite bullions. Conifers are first suggested by late Mississippian Potoniesporites pollen. About the same time, in North America, broadleaf foliage, Lesleya and Megalopteris occur in basin-margin settings, on drought-prone limestone substrates. The best known, xeromorphic floras found between coal beds appear in the Middle through Late Pennsylvanian, containing conifers, cordaitaleans, and pteridosperms. The Middle Pennsylvanian appearances of this flora are mainly allochthonous, though parautochthonous occurrences have been reported. Parautochthonous assemblages are mostly Late Pennsylvanian. The conifer flora became dominant in western and central Pangaean equatorial lowlands in earliest Permian. Location of the humid-perhumid wetland flora during periods of relative dryness, though rarely discussed, is as, or more, perplexing than the spatial location of seasonally-dry floras through

Spatio-temporal monitoring of vegetation phenology in the dry sub-humid region of Nigeria using time series of AVHRR NDVI and TAMSAT datasets

Science.gov (United States)

Osunmadewa, Babatunde Adeniyi; Gebrehiwot, Worku Zewdie; Csaplovics, Elmar; Adeofun, Olabinjo Clement

2018-03-01

Time series data are of great importance for monitoring vegetation phenology in the dry sub-humid regions where change in land cover has influence on biomass productivity. However few studies have inquired into examining the impact of rainfall and land cover change on vegetation phenology. This study explores Seasonal Trend Analysis (STA) approach in order to investigate overall greenness, peak of annual greenness and timing of annual greenness in the seasonal NDVI cycle. Phenological pattern for the start of season (SOS) and end of season (EOS) was also examined across different land cover types in four selected locations. A significant increase in overall greenness (amplitude 0) and a significant decrease in other greenness trend maps (amplitude 1 and phase 1) was observed over the study period. Moreover significant positive trends in overall annual rainfall (amplitude 0) was found which follows similar pattern with vegetation trend. Variation in the timing of peak of greenness (phase 1) was seen in the four selected locations, this indicate a change in phenological trend. Additionally, strong relationship was revealed by the result of the pixel-wise regression between NDVI and rainfall. Change in vegetation phenology in the study area is attributed to climatic variability than anthropogenic activities.

Spatio-temporal monitoring of vegetation phenology in the dry sub-humid region of Nigeria using time series of AVHRR NDVI and TAMSAT datasets

Directory of Open Access Journals (Sweden)

Osunmadewa Babatunde Adeniyi

2018-03-01

Full Text Available Time series data are of great importance for monitoring vegetation phenology in the dry sub-humid regions where change in land cover has influence on biomass productivity. However few studies have inquired into examining the impact of rainfall and land cover change on vegetation phenology. This study explores Seasonal Trend Analysis (STA approach in order to investigate overall greenness, peak of annual greenness and timing of annual greenness in the seasonal NDVI cycle. Phenological pattern for the start of season (SOS and end of season (EOS was also examined across different land cover types in four selected locations. A significant increase in overall greenness (amplitude 0 and a significant decrease in other greenness trend maps (amplitude 1 and phase 1 was observed over the study period. Moreover significant positive trends in overall annual rainfall (amplitude 0 was found which follows similar pattern with vegetation trend. Variation in the timing of peak of greenness (phase 1 was seen in the four selected locations, this indicate a change in phenological trend. Additionally, strong relationship was revealed by the result of the pixel-wise regression between NDVI and rainfall. Change in vegetation phenology in the study area is attributed to climatic variability than anthropogenic activities.

Tropical forest biomass and successional age class relationships to a vegetation index derived from Landsat TM data

Science.gov (United States)

Sader, Steven A.; Waide, Robert B.; Lawrence, William T.; Joyce, Armond T.

1989-01-01

Forest stand structure and biomass data were collected using conventional forest inventory techniques in tropical, subtropical, and warm temperate forest biomes. The feasibility of detecting tropical forest successional age class and total biomass differences using Landsat-Thematic mapper (TM) data, was evaluated. The Normalized Difference Vegetation Index (NDVI) calculated from Landsat-TM data were not significantly correlated with forest regeneration age classes in the mountain terrain of the Luquillo Experimental Forest, Puerto Rico. The low sun angle and shadows cast on steep north and west facing slopes reduced spectral reflectance values recorded by TM orbital altitude. The NDVI, calculated from low altitude aircraft scanner data, was significatly correlated with forest age classes. However, analysis of variance suggested that NDVI differences were not detectable for successional forests older than approximately 15-20 years. Also, biomass differences in young successional tropical forest were not detectable using the NDVI. The vegetation index does not appear to be a good predictor of stand structure variables (e.g., height, diameter of main stem) or total biomass in uneven age, mixed broadleaf forest. Good correlation between the vegetation index and low biomass in even age pine plantations were achieved for a warm temperate study site. The implications of the study for the use of NDVI for forest structure and biomass estimation are discussed.

Plant functional diversity affects climate-vegetation interaction

Science.gov (United States)

Groner, Vivienne P.; Raddatz, Thomas; Reick, Christian H.; Claussen, Martin

2018-04-01

We present how variations in plant functional diversity affect climate-vegetation interaction towards the end of the African Humid Period (AHP) in coupled land-atmosphere simulations using the Max Planck Institute Earth system model (MPI-ESM). In experiments with AHP boundary conditions, the extent of the green Sahara varies considerably with changes in plant functional diversity. Differences in vegetation cover extent and plant functional type (PFT) composition translate into significantly different land surface parameters, water cycling, and surface energy budgets. These changes have not only regional consequences but considerably alter large-scale atmospheric circulation patterns and the position of the tropical rain belt. Towards the end of the AHP, simulations with the standard PFT set in MPI-ESM depict a gradual decrease of precipitation and vegetation cover over time, while simulations with modified PFT composition show either a sharp decline of both variables or an even slower retreat. Thus, not the quantitative but the qualitative PFT composition determines climate-vegetation interaction and the climate-vegetation system response to external forcing. The sensitivity of simulated system states to changes in PFT composition raises the question how realistically Earth system models can actually represent climate-vegetation interaction, considering the poor representation of plant diversity in the current generation of land surface models.

Investigating Strategies for Sustainable Vegetable Food Crop System in Three Agro Ecological Zones of the Humid Tropics Area of Cameroon

OpenAIRE

TATA NGOME, Precillia Ijang; AFARI-SEFA, Victor; NTSOMBOH-NTSEFONG, Godswill; OKOLLE, Justin; BILLA, Samuel Fru; MOMA, Crescence; ATEMKENG FONJI, Maureen; NGOME, Ajebesone Francis

2018-01-01

Vegetable cultivation remains an essential component of local people’s livelihoods. However, marked trend shifts in the varieties of vegetables due to large-scale commercial vegetable farming of exotic varieties in the broader market economy have resulted in the gradual disappearance of biodiversity involving vital species. The present study examined the situation of vegetable crop farming in three agro-ecological zones of Cameroon. Data were collected from a random sample of 235 respondents ...

Tropical vegetation evidence for rapid sea level changes associated with Heinrich Events

Energy Technology Data Exchange (ETDEWEB)

Gonzalez, Catalina; Dupont, Lydie M, E-mail: catalina@uni-bremen.d, E-mail: dupont@uni-bremen.d [MARUM - Centre for Marine Environmental Sciences, University of Bremen, Leobener Strasse, D-28359 Germany (Germany)

2010-03-15

A Cariaco Basin pollen record shows the development of tropical salt marshes during marine isotope stage 3. Rapid and abrupt expansions of salt marsh vegetation in tropical South America are associated with north Atlantic Heinrich Events stadials (HE-stadials). Intervals of salt marsh expansion have an internal structure, which consists of a recurrent alternation of species that starts with pollen increments of Chenopodiaceae, that are followed by increments of grasses, and subsequently by increments of Cyperaceae. This pattern suggests a successional process that is determined by the close relationship between sea-level and plant community dynamics. The salt tolerant Chenopodiaceae, indicate hypersaline intertidal environments, which were most likely promoted by extremely dry atmospheric conditions. Rapid sea-level rise characterizes the onset of HE-stadials, causing the continued recruitment of pioneer species, which are the only ones tolerating rapid rates of disturbance. Once sea-level rise decelerates, marsh plants are able to trap and stabilize sediments, favouring the establishment of more competitive species. These results add to the scarce knowledge on the dynamics of tropical salt marsh ecosystems, and provide independent paleoclimatic evidence on sea-level changes following Antarctic climate variability.

The Vertical Structure of Relative Humidity and Ozone in the Tropical Upper Troposphere: Intercomparisons Among In Situ Observations, A-Train Measurements and Large-Scale Models

Science.gov (United States)

Selkirk, Henry B.; Manyin, Michael; Douglass, Anne R.; Oman, Luke; Pawson, Steven; Ott, Lesley; Benson, Craig; Stolarski, Richard

2010-01-01

In situ measurements in the tropics have shown that in regions of active convection, relative humidity with respect to ice in the upper troposphere is typically close to saturation on average, and supersaturations greater than 20% are not uncommon. Balloon soundings with the cryogenic frost point hygrometer (CFH) at Costa Rica during northern summer, for example, show this tendency to be strongest between 11 and 15.5 km (345-360 K potential temperature, or approximately 250-120 hPa). this is the altitude range of deep convective detrainment. Additionally, simultaneous ozonesonde measurements show that stratospheric air (O3 greater than 150 ppbv) can be found as low as approximately 14 km (350 K/150 hPa). In contrast, results from northern winter show a much drier upper troposphere and little penetration of stratospheric air below the tropopause at 17.5 km (approximately 383 K). We show that these results are consistent with in situ measurements from the Measurement of Ozone and water vapor by Airbus In-service airCraft (MOZAIC) program which samples a wider, though still limited, range of tropical locations. To generalize to the tropics as a whole, we compare our insitu results to data from two A-Train satellite instruments, the Atmospheric Infrared Sounder (AIRS) and the Microwave Limb Sounder (MLS) on the Aqua and Aura satellites respectively. Finally, we examine the vertical structure of water vapor, relative humidity and ozone in the NASA Goddard MERRA analysis, an assimilation dataset, and a new version of the GEOS CCM, a free-running chemistry-climate model. We demonstrate that conditional probability distributions of relative humidity and ozone are a sensitive diagnostic for assessing the representation of deep convection and upper troposphere/lower stratosphere mixing processes in large-scale analyses and climate models.

Impact of Soil and Water Conservation Interventions on Watershed Runoff Response in a Tropical Humid Highland of Ethiopia.

Science.gov (United States)

Sultan, Dagnenet; Tsunekawa, Atsushi; Haregeweyn, Nigussie; Adgo, Enyew; Tsubo, Mitsuru; Meshesha, Derege Tsegaye; Masunaga, Tsugiyuki; Aklog, Dagnachew; Fenta, Ayele Almaw; Ebabu, Kindiye

2018-05-01

Various soil and water conservation measures (SWC) have been widely implemented to reduce surface runoff in degraded and drought-prone watersheds. But little quantitative study has been done on to what extent such measures can reduce watershed-scale runoff, particularly from typical humid tropical highlands of Ethiopia. The overall goal of this study is to analyze the impact of SWC interventions on the runoff response by integrating field measurement with a hydrological CN model which gives a quantitative analysis future thought. Firstly, a paired-watershed approach was employed to quantify the relative difference in runoff response for the Kasiry (treated) and Akusty (untreated) watersheds. Secondly, a calibrated curve number hydrological modeling was applied to investigate the effect of various SWC management scenarios for the Kasiry watershed alone. The paired-watershed approach showed a distinct runoff response between the two watersheds however the effect of SWC measures was not clearly discerned being masked by other factors. On the other hand, the model predicts that, under the current SWC coverage at Kasiry, the seasonal runoff yield is being reduced by 5.2%. However, runoff yields from Kasiry watershed could be decreased by as much as 34% if soil bunds were installed on cultivated land and trenches were installed on grazing and plantation lands. In contrast, implementation of SWC measures on bush land and natural forest would have little effect on reducing runoff. The results on the magnitude of runoff reduction under optimal combinations of SWC measures and land use will support decision-makers in selection and promotion of valid management practices that are suited to particular biophysical niches in the tropical humid highlands of Ethiopia.

Effect of the food production chain from farm practices to vegetable processing on outbreak incidence.

Science.gov (United States)

Jung, Yangjin; Jang, Hyein; Matthews, Karl R

2014-11-01

The popularity in the consumption of fresh and fresh-cut vegetables continues to increase globally. Fresh vegetables are an integral part of a healthy diet, providing vitamins, minerals, antioxidants and other health-promoting compounds. The diversity of fresh vegetables and packaging formats (spring mix in clamshell container, bagged heads of lettuce) support increased consumption. Unfortunately, vegetable production and processing practices are not sufficient to ensure complete microbial safety. This review highlights a few specific areas that require greater attention and research. Selected outbreaks are presented to emphasize the need for science-based 'best practices'. Laboratory and field studies have focused on inactivation of pathogens associated with manure in liquid, slurry or solid forms. As production practices change, other forms and types of soil amendments are being used more prevalently. Information regarding the microbial safety of fish emulsion and pellet form of manure is limited. The topic of global climate change is controversial, but the potential effect on agriculture cannot be ignored. Changes in temperature, precipitation, humidity and wind can impact crops and the microorganisms that are associated with production environments. Climate change could potentially enhance the ability of pathogens to survive and persist in soil, water and crops, increasing human health risks. Limited research has focused on the prevalence and behaviour of viruses in pre and post-harvest environments and on vegetable commodities. Globally, viruses are a major cause of foodborne illnesses, but are seldom tested for in soil, soil amendments, manure and crops. Greater attention must also be given to the improvement in the microbial quality of seeds used in sprout production. Human pathogens associated with seeds can result in contamination of sprouts intended for human consumption, even when all appropriate 'best practices' are used by sprout growers. © 2014 The

Lower-tropospheric humidity: climatology, trends and the relation to the ITCZ

Directory of Open Access Journals (Sweden)

Alexander Läderach

2013-07-01

Full Text Available The tropical region is an area of maximum humidity and serves as the major humidity source of the globe. Among other phenomena, it is governed by the so-called Inter-Tropical Convergence Zone (ITCZ which is commonly defined by converging low-level winds or enhanced precipitation. Given its importance as a humidity source, we investigate the humidity fields in the tropics in different reanalysis data sets, deduce the climatology and variability and assess the relationship to the ITCZ. Therefore, a new analysis method of the specific humidity distribution is introduced which allows detecting the location of the humidity maximum, the strength and the meridional extent. The results show that the humidity maximum in boreal summer is strongly shifted northward over the warm pool/Asia Monsoon area and the Gulf of Mexico. These shifts go along with a peak in the strength in both areas; however, the extent shrinks over the warm pool/Asia Monsoon area, whereas it is wider over the Gulf of Mexico. In winter, such connections between location, strength and extent are not found. Still, a peak in strength is again identified over the Gulf of Mexico in boreal winter. The variability of the three characteristics is dominated by inter-annual signals in both seasons. The results using ERA-interim data suggest a positive trend in the Gulf of Mexico/Atlantic region from 1979 to 2010, showing an increased northward shift in the recent years. Although the trend is only weakly confirmed by the results using MERRA reanalysis data, it is in phase with a trend in hurricane activity – a possible hint of the importance of the new method on hurricanes. Furthermore, the position of the maximum humidity coincides with one of the ITCZ in most areas. One exception is the western and central Pacific, where the area is dominated by the double ITCZ in boreal winter. Nevertheless, the new method enables us to gain more insight into the humidity distribution, its variability and

Assessing risk to human health from tropical leafy vegetables grown on contaminated urban soils

International Nuclear Information System (INIS)

Nabulo, G.; Young, S.D.; Black, C.R.

2010-01-01

Fifteen tropical leafy vegetable types were sampled from farmers' gardens situated on nine contaminated sites used to grow vegetables for commercial or subsistence consumption in and around Kampala City, Uganda. Trace metal concentrations in soils were highly variable and originated from irrigation with wastewater, effluent discharge from industry and dumping of solid waste. Metal concentrations in the edible shoots of vegetables also differed greatly between, and within, sites. Gynandropsis gynandra consistently accumulated the highest Cd, Pb and Cu concentrations, while Amaranthus dubius accumulated the highest Zn concentration. Cadmium uptake from soils with contrasting sources and severity of contamination was consistently lowest in Cucurbita maxima and Vigna unguiculata, suggesting these species were most able to restrict Cd uptake from contaminated soil. Concentrations of Pb and Cr were consistently greater in unwashed, than in washed, vegetables, in marked contrast to Cd, Ni and Zn. The risk to human health, expressed as a 'hazard quotient' (HQ M ), was generally greatest for Cd, followed successively by Pb, Zn, Ni and Cu. Nevertheless, it was apparent that urban cultivation of leafy vegetables could be safely pursued on most sites, subject to site-specific assessment of soil metal burden, judicious choice of vegetable types and adoption of washing in clean water prior to cooking.

Emerging new poleroviruses and tospoviruses affecting vegetables in Asia and breeding for resistance

NARCIS (Netherlands)

Relevante, C.; Cheewachaiwit, S.; Chuapong, J.; Stratongjun, M.; Salutan, V.E.; Peters, D.; Balatero, C.H.; Hoop, de S.J.

2012-01-01

The diseases caused by aphid-borne poleroviruses (genus Polerovirus, family Luteoviridae) and thrips-borne tospoviruses (genus Tospovirus, family Bunyaviridae) are emerging threats to the production of economically important vegetable and fruit crops in tropical and sub-tropical Asia. To date, at

Primary production of tropical marine ecosystems

Digital Repository Service at National Institute of Oceanography (India)

Bhattathiri, P.M.A.

Among tropical marine ecosystems estuaries are one of the highly productive areas and act as a nursery to large number of organisms. The primary production in most of the estuaries is less during the monsoon period. Post-monsoon period shows...

Tropical Fruit Pulps: Processing, Product Standardization and Main Control Parameters for Quality Assurance

Directory of Open Access Journals (Sweden)

Carlos Eduardo de Farias Silva

2017-05-01

Full Text Available ABSTRACT Fruit pulp is the most basic food product obtained from fresh fruit processing. Fruit pulps can be cold stored for long periods of time, but they also can be used to fabricate juices, ice creams, sweets, jellies and yogurts. The exploitation of tropical fruits has leveraged the entire Brazilian fruit pulp sector due mainly to the high acceptance of their organoleptic properties and remarkable nutritional facts. However, several works published in the last decades have pointed out unfavorable conditions regarding the consumption of tropical fruit pulps. This negative scenario has been associated with unsatisfactory physico-chemical and microbiological parameters of fruits pulps as outcomes of little knowledge and improper management within the fruit pulp industry. There are protocols for delineating specific identity and quality standards (IQSs and standardized good manufacturing practices (GMP for fruit pulps, which also embrace standard operating procedures (SOPs and hazard analysis and critical control points (HACCP, although this latter is not considered mandatory by the Brazilian legislation. Unfortunately, the lack of skilled labor, along with failures in complying established protocols have impaired quality of fruit pulps. It has been necessary to collect all information available with the aim to identify the most important hazards within fruit pulp processing lines. Standardizing methods and practices within the Brazilian fruit pulp industry would assurance high quality status to tropical fruit pulps and the commercial growth of this vegetal product towards international markets.

Comparison of land surface humidity between observations and CMIP5 models

Science.gov (United States)

Dunn, Robert J. H.; Willett, Kate M.; Ciavarella, Andrew; Stott, Peter A.

2017-08-01

We compare the latest observational land surface humidity dataset, HadISDH, with the latest generation of climate models extracted from the CMIP5 archive and the ERA-Interim reanalysis over the period 1973 to present. The globally averaged behaviour of HadISDH and ERA-Interim are very similar in both humidity measures and air temperature, on decadal and interannual timescales. The global average relative humidity shows a gradual increase from 1973 to 2000, followed by a steep decline in recent years. The observed specific humidity shows a steady increase in the global average during the early period but in the later period it remains approximately constant. None of the CMIP5 models or experiments capture the observed behaviour of the relative or specific humidity over the entire study period. When using an atmosphere-only model, driven by observed sea surface temperatures and radiative forcing changes, the behaviour of regional average temperature and specific humidity are better captured, but there is little improvement in the relative humidity. Comparing the observed climatologies with those from historical model runs shows that the models are generally cooler everywhere, are drier and less saturated in the tropics and extra-tropics, and have comparable moisture levels but are more saturated in the high latitudes. The spatial pattern of linear trends is relatively similar between the models and HadISDH for temperature and specific humidity, but there are large differences for relative humidity, with less moistening shown in the models over the tropics and very little at high latitudes. The observed drying in mid-latitudes is present at a much lower magnitude in the CMIP5 models. Relationships between temperature and humidity anomalies (T-q and T-rh) show good agreement for specific humidity between models and observations, and between the models themselves, but much poorer for relative humidity. The T-q correlation from the models is more steeply positive than

NEW GREENHOUSE TECHNOLOGIES FOR VEGETABLE PRODUCTION

Directory of Open Access Journals (Sweden)

S. M. Sirota

2016-01-01

Full Text Available First decade of XXI century is characterized by significant augmentation in vegetable world’s production. Average annual vegetable production has been 346 million tons, and it has exceeded the average annual potato production (318 million tons. It has occurred due to the use of up-to-date technologies for vegetable production and, particularly, in greenhouses. In Russian Federation, the total production of vegetables was 5 275.6 thousand tons in 2015 that was 13.3% more than in 2014. But the total vegetable production in greenhouses was only 722.8 thousand tons, that was 0.7% less than in 2014 (728.1 thousand tons. It can be explained that the old technologies have been used for many greenhouses around Russia. Up-to-date technologies for greenhouses are described in the article. Small-volume hydroponics. Plants are grown in mineral wadding, packed up in the special chutes. Mineral nutrition and water are supplied through special pipe with many branch pipes toward each plant. Advantage: pH and nutrition are maintained, consumption of water and mineral nutrition are optimized, and that improves plants grow control. Expenditures of labor decreased, quality of fruit became better and the yield increased significantly by 45-50 kg/m2 comparing with growing on the soil (25-30 kg/m2. Hydroponics with flowing water (salad production lines. Conveyor for salad and vegetable growing on horizontal moving chutes with flowing water and nutrition was developed. Advantage: high level of automation and mechanization of all processes of growing increased the effectiveness of the use of greenhouse areas (we can place 30% plants more at the same area. Seedling production lines. Production lines for seedlings enable to grow vegetables and leafy vegetables on stationary benches, being furnished with periodical nutrition and water supply at times. Advantage: 700 seedlings additionally on each m2 a year. Future technologies are

Vegetation and floristics of a lowland tropical rainforest in northeast Australia.

Science.gov (United States)

Tng, David Y P; Apgaua, Deborah M G; Campbell, Mason J; Cox, Casey J; Crayn, Darren M; Ishida, Françoise Y; Laidlaw, Melinda J; Liddell, Michael J; Seager, Michael; Laurance, Susan G W

2016-01-01

Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m(2) quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m(2) ha(-1), of which small stems (tree saplings and shrubs analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest. We present a floristic checklist, a lifeform breakdown, and demography data from two 1-ha rainforest plots from a lowland tropical rainforest study site. We also present a meta-analysis of stem densities and species diversity from

Cyclic changes in Pennsylvanian paleoclimate and effects on floristic dynamics in tropical Pangaea

Energy Technology Data Exchange (ETDEWEB)

DiMichele, William A. [National Museum of Natural History MRC-121, Smithsonian Institution, Washington, DC 20560 (United States); Cecil, C. Blaine [National Museum of Natural History MRC-121, Smithsonian Institution, Washington, DC 20560 (United States); U.S. Geological Survey, Reston, VA 20192 (United States); Montanez, Isabel P. [Department of Geology, University of California, Davis, CA 95616 (United States); Falcon-Lang, Howard J. [Department of Earth Sciences, Royal Holloway, University of London, Egham, Surrey TW20 0EX (United Kingdom)

2010-08-01

Wetland floras narrowly define perceptions of Pennsylvanian tropical ecosystems, the so-called Coal Age. Such wetlands reflect humid to perhumid climate, leading to characterizations of Pennsylvanian tropics as everwet, swampy. These views are biased by the high preservation potential of wetlands. Sedimentation patterns, paleosols, and fossil floras indicate the presence of vegetation tolerant of subhumid to dry-subhumid, perhaps semi-arid climate in basins between peat formation times. Understanding the significance of this seasonally-dry vegetation has suffered from conceptual and terminological confusion. A clearer view has emerged as models for framing the data have improved. Basinal floras typical of seasonally-dry conditions, relatively low soil moisture regimes, are well documented but mainly from isolated deposits. Some of the earliest, dominated by primitive pteridosperms (''Floezfern'' floras), occur in clastic rocks between European Early Pennsylvanian coal beds. Later Early Pennsylvanian, fern-cordaitalean vegetation, different from coal floras, is preserved in marine goniatite bullions. Conifers are first suggested by late Mississippian Potoniesporites pollen. About the same time, in North America, broadleaf foliage, Lesleya and Megalopteris occur in basin-margin settings, on drought-prone limestone substrates. The best known, xeromorphic floras found between coal beds appear in the Middle through Late Pennsylvanian, containing conifers, cordaitaleans, and pteridosperms. The Middle Pennsylvanian appearances of this flora are mainly allochthonous, though parautochthonous occurrences have been reported. Parautochthonous assemblages are mostly Late Pennsylvanian. The conifer flora became dominant in western and central Pangaean equatorial lowlands in earliest Permian. Location of the humid-perhumid wetland flora during periods of relative dryness, though rarely discussed, is as, or more, perplexing than the spatial location of

Artificial Fruit: Postharvest Online Monitoring of Agricultural Food by Measuring Humidity and Temperature

Science.gov (United States)

Hübert, T.; Lang, C.

2012-09-01

An online monitoring of environmental and inherent product parameters is required during transportation and storage of fruit and vegetables to avoid quality degradation and spoilage. The control of transpiration losses is suggested as an indicator for fruit freshness by humidity measurements. For that purpose, an electronic sensor is surrounded by a wet porous fiber material which is in contact with the outer atmosphere. Transpiration reduces the water content of the porous material and thus also the internal water activity. The sensor system, known as "artificial fruit," measures the relative humidity and temperature inside the wet material. Humidity and temperature data are collected and transmitted on demand by a miniaturized radio communication unit. The decrease in the measured relative humidity has been calibrated against the mass loss of tomatoes under different external influencing parameters such as temperature, humidity, and air flow. Current battery life allows the sensor system, embedded in a fruit crate, to transmit data on transpiration losses via radio transmission for up to two weeks.

Seasonally asymmetric enhancement of northern vegetation productivity

Science.gov (United States)

Park, T.; Myneni, R.

2017-12-01

Multiple evidences of widespread greening and increasing terrestrial carbon uptake have been documented. In particular, enhanced gross productivity of northern vegetation has been a critical role leading to observed carbon uptake trend. However, seasonal photosynthetic activity and its contribution to observed annual carbon uptake trend and interannual variability are not well understood. Here, we introduce a multiple-source of datasets including ground, atmospheric and satellite observations, and multiple process-based global vegetation models to understand how seasonal variation of land surface vegetation controls a large-scale carbon exchange. Our analysis clearly shows a seasonally asymmetric enhancement of northern vegetation productivity in growing season during last decades. Particularly, increasing gross productivity in late spring and early summer is obvious and dominant driver explaining observed trend and variability. We observe more asymmetric productivity enhancement in warmer region and this spatially varying asymmetricity in northern vegetation are likely explained by canopy development rate, thermal and light availability. These results imply that continued warming may facilitate amplifying asymmetric vegetation activity and cause these trends to become more pervasive, in turn warming induced regime shift in northern land.

Initial stages of indoor atmospheric corrosion of electronics contact metals in humid tropical climate: tin and nickel

Directory of Open Access Journals (Sweden)

Veleva, L.

2007-04-01

Full Text Available Samples of electrolytic tin and nickel have been exposed for 1 to 12 m in indoor environment, inside a box (rain sheltered cabinet, placed in tropical humid marine-urban climate, as a part of Gulf of Mexico. The corrosion aggressiveness of box has been classified as a very high corrosive, based on the monitored chlorides and SO₂ deposition rates, and the Temperature/Relative Humidity air daily complex. The annual mass increasing of nickel is approximately twice higher than its values of mass loss (C. The relation between nickel mass loss or increasing and time of wetness (t of metal surface is linear and does not obey the power equation C = A tⁿ, which has be found for tin. The SEM images reveal a localized corrosion on nickel and tin surfaces. XRD detects the formation of SnCl₂.H₂O as a corrosion product. Within the time on the tin surface appear black spots, considered as organic material.

Muestras de estaño y níquel electrolíticos han sido expuestas de 1 a 12 m en ambiente interno (indoor, en una caseta (gabinete protegido de lluvia, colocada en clima tropical húmedo marino-urbano del Golfo de México. La agresividad de la caseta ha sido clasificada como muy altamente corrosiva, basada al registro de la velocidad de deposición de cloruros y SO₂, y en el complejo diario de temperatura/humedad relativa del aire. El incremento de masa anual de níquel es, aproximadamente, dos veces mayor que del valor de su pérdida de masa (C. La relación entre la pérdida de masa de Ni o su incremento, y el tiempo de humectación (t de la superficie metálica y lineal y no obedece la ley de potencia C = A tⁿ , que ha sido encontrada para el estaño. Las imágenes del SEM revelan una corrosión localizada en las superficie de níquel y estaño. El análisis de rayos-X detecta la formación de SnCl₂.H₂O como producto de corrosión. Con el tiempo

Tropical crops as a basic source of food

Energy Technology Data Exchange (ETDEWEB)

Araujo, J.E.G.

1979-01-01

A study is made of the potential that exists for food production in the Latin American tropics, and ways in which this could improve and diversify nutritional patterns in other ecological regions. Crops which could become more important include roots and tubers, varieties of beans, fruits, nuts and vegetables. Tropical crops such as sugar cane and cassava could also be used as renewable sources of energy, to replace conventional non-renewable fuels.

Forest vegetation of Xishuangbanna, south China

Institute of Scientific and Technical Information of China (English)

Zhu Hua

2006-01-01

Xishuangbanna of southern Yunnan is biogeographically located at a transitional zone from tropical southeast (SE) Asia to subtropical east Asia and is at the junction of the Indian and Burmese plates of Gondwana and the Eurasian plate of Laurasia. The region, though surprisingly far from the equator and at a relatively high altitude, has a rich tropical flora and a typical tropical rain forest in the lowland areas. Based on physiognomic and ecological characteristics, floristic composition and habitats combined, the primary vegetation in Xishuangbanna can be organized into four main vegetation types: tropical rain forest, tropical seasonal moist forest, tropical montane evergreen broad-leaved forest and tropical monsoon forest. The tropical rain forest can be classified into two subtypes, i.e. a tropical seasonal rain forest in the lowlands and a tropical montane rain forest at higher elevations. The tropical seasonal rain forest has almost the same forest profile and physiognomic characteristics as equatorial lowland rain forests and is a type of truly tropical rain forest. Because of conspicuous similarity on ecological and floristic characteristics, the tropical rain forest in Xishuangbanna is a type of tropical Asian rain forest. However, since the tropical rain forest of Xishuangbanna occurs at the northern edge of tropical SE Asia, it differs from typical lowland rain forests in equatorial areas in having some deciduous trees in the canopy layer, fewer megaphanerophytes and epiphytes but more abundant lianas and more plants with microphyll. It is a type of semi-evergreen rain forest at the northern edge of the tropical zone. The tropical montane rain forest occurs at wet montane habitats and is similar to the lower montane rain forest in equatorial Asia in floristic composition and physiognomy. It is a type of lower montane rain forests within the broader category of tropical rain forests. The tropical seasonal moist forest occurs on middle and upper

A critical assessment of the JULES land surface model hydrology for humid tropical environments

Science.gov (United States)

Zulkafli, Z.; Buytaert, W.; Onof, C.; Lavado, W.; Guyot, J. L.

2013-03-01

Global land surface models (LSMs) such as the Joint UK Land Environment Simulator (JULES) are originally developed to provide surface boundary conditions for climate models. They are increasingly used for hydrological simulation, for instance to simulate the impacts of land use changes and other perturbations on the water cycle. This study investigates how well such models represent the major hydrological fluxes at the relevant spatial and temporal scales - an important question for reliable model applications in poorly understood, data-scarce environments. The JULES-LSM is implemented in a 360 000 km2 humid tropical mountain basin of the Peruvian Andes-Amazon at 12-km grid resolution, forced with daily satellite and climate reanalysis data. The simulations are evaluated using conventional discharge-based evaluation methods, and by further comparing the magnitude and internal variability of the basin surface fluxes such as evapotranspiration, throughfall, and surface and subsurface runoff of the model with those observed in similar environments elsewhere. We find reasonably positive model efficiencies and high correlations between the simulated and observed streamflows, but high root-mean-square errors affecting the performance in smaller, upper sub-basins. We attribute this to errors in the water balance and JULES-LSM's inability to model baseflow. We also found a tendency to under-represent the high evapotranspiration rates of the region. We conclude that strategies to improve the representation of tropical systems to be (1) addressing errors in the forcing and (2) incorporating local wetland and regional floodplain in the subsurface representation.

Diffusion coefficients for unattached decay products of thoron - dependence on ventilation and relative humidity

International Nuclear Information System (INIS)

Kotrappa, P.; Bhanti, D.P.; Raghunath, B.

1976-01-01

The results of a study of the diffusivity of unattached decay products of thoron with respect to air changes using a recently developed diffusion sampler are reported. The dependence of diffusivity of radon/thoron decay products on relative humidity has also been investigated by measurement of diffusion coefficients in an atmosphere where relative humidities varied from 5 to 90%. Results are shown tabulated. (U.K.)

Tropical vegetable fats and butters: properties and new alternatives

Directory of Open Access Journals (Sweden)

J Salas Joaquín

2009-07-01

Full Text Available Tropical fats and butters are characterized by their high contents of saturated fatty acids, which confer to them melting points and rheological properties adequate for the production of high valuable food commodities. We can distinguish 3 groups of tropical fats: those having medium chain fatty acids, like coconut or palm kernel oils, those rich in palmitic acid, like palm oil and its fractions, and those rich in stearic acid like cocoa butter. Modern biotechnology has provided with alternatives to these species in engineered common oil crops enriched in saturated fatty acids and processes aimed to enrich common oils in disaturated TAGs by enzymatic transesterification. The present and future of these new sources of saturated fats are discussed in this work.

Effects of tropical montane forest disturbance on epiphytic macrolichens

International Nuclear Information System (INIS)

Benítez, Ángel; Prieto, María; González, Yadira; Aragón, Gregorio

2012-01-01

The high diversity of epiphytes typical of undisturbed montane tropical forests has been negatively affected by continuous deforestation and forest conversion to secondary vegetation. Macrolichens are an important component of these epiphytes. Because their physiology is strongly coupled to humidity and solar radiation, we hypothesized that microclimatic changes derived from forest clearing and logging can affect the diversity of these poikilohydric organisms. In southern Ecuador, we examined three types of forests according to a disturbance gradient (primary forests, secondary forests, and monospecific forests of Alnus acuminata) for the presence/absence and coverage of epiphytic macrolichens that we identified on 240 trees. We found that total richness tended to decrease when the range of the disturbance increased. The impoverishment was particularly drastic for “shade-adapted lichens”, while the richness of “heliophytic lichens” increased in the drier conditions of secondary growth. Epiphytic composition also differed significantly among the three types of forests, and the similarity decreased when the range of the disturbance was greater. We concluded that a span of 40 years of recovery by secondary vegetation was not enough to regenerate the diversity of epiphytic macrolichens that was lost due to forest disturbances. -- Highlights: ► Tropical montane forest disturbance drastically reduced macrolichen diversity. ► Species loss was most severe for the “shade-adapted lichens” because high radiation is harmful to them. ► In secondary forests lichen diversity of native forests was not regenerated. ► The protection of remnants of primary tropical forest might help to preserve a diverse community of epiphytic macrolichens.

Applications of NASA TROPICS Data for Tropical Cyclone Analysis, Nowcasting, and Impacts

Science.gov (United States)

Zavodsky, B.; Dunion, J. P.; Blackwell, W. J.; Braun, S. A.; Green, D. S.; Velden, C.; Adler, R. F.; Cossuth, J.; Murray, J. J.; Brennan, M. J.

2017-12-01

The National Aeronautics and Space Administration (NASA) Time-Resolved Observations of Precipitation structure and storm Intensity with a Constellation of Smallsats (TROPICS) mission is a constellation of state-of-the-science observing platforms that will measure temperature and humidity soundings and precipitation with spatial resolution comparable to current operational passive microwave sounders but with unprecedented temporal resolution. TROPICS is a cost-capped ($30M) Venture-class mission funded by the NASA Earth Science Division. The mission is comprised of a constellation of 3 unit (3U) SmallSats, each hosting a 12-channel passive microwave spectrometer based on the Micro-sized Microwave Atmospheric Satellite 2 (MicroMAS-2) developed at MIT LL. TROPICS will provide imagery near 91 and 205 GHz, temperature sounding near 118 GHz, and moisture sounding near 183 GHz. Spatial resolution at nadir will be around 27 km for temperature and 17 km for moisture and precipitation. The swath width is approximately 2000 km. TROPICS enables temporal resolution similar to geostationary orbit but at a much lower cost, demonstrating a technology that could impact the design of future Earth-observing missions. The TROPICS satellites for the mission are slated for delivery to NASA in 2019 with potential launch opportunities in 2020. The primary mission objective of TROPICS is to relate temperature, humidity, and precipitation structure to the evolution of tropical cyclone (TC) intensity. This abstract summarizes the outcomes of the 1st TROPICS Applications Workshop, held from May 8-10, 2017 at the University of Miami. At this meeting, a series of presentations and breakout discussions in the topical areas of Tropical Cyclone Dynamics, Tropical Cyclone Analysis and Nowcasting, Tropical Cyclone Modeling and Data Assimilation, and Terrestrial Impacts were convened to identify applications of the mission data and to begin to establish a community of end-users who will be able to

Natural and near natural tropical forest values

Science.gov (United States)

Daniel H. Henning

2011-01-01

This paper identifies and describes some of the values associated with tropical rain forests in their natural and near-natural conditions. Tropical rain forests are moist forests in the humid tropics where temperature and rainfall are high and the dry season is short. These closed (non-logged) and broad-leaved forests are a global resource. Located almost entirely in...

Ozone Production With Dielectric Barrier Discharge: Effects of Power Source and Humidity

KAUST Repository

Zhang, Xuming

2016-08-24

Ozone synthesis in air dielectric barrier discharge (DBD) was studied with an emphasis on the effects of power sources and humidity. Discharge characteristics were investigated to understand the physical properties of plasma and corresponding system performance. It was found that 10-ns pulsed DBD produced a homogeneous discharge mode, while ac DBD yielded an inhomogeneous pattern with many microdischarge channels. At a similar level of the energy density (ED), decreasing the flowrate is more effective in the production of ozone for the cases of the ac DBD, while increased voltage is more effective for the pulsed DBD. Note that the maximum ozone production efficiency (110 g/kWh) was achieved with the pulsed DBD. At the ED of ∼ 85 J/L, the ozone concentrations with dry air were over three times higher than those with the relative humidity of 100% for both the ac DBD and pulsed DBD cases. A numerical simulation was conducted using a global model to understand a detailed chemical role of water vapor to ozone production. It was found HO and OH radicals from water vapor significantly consumed O atoms, resulting in a reduction in ozone production. The global model qualitatively captured the experimental trends, providing further evidence that the primary effect of humidity on ozone production is chemical in nature.

Clay mineralogy indicates a mildly warm and humid living environment for the Miocene hominoid from the Zhaotong Basin, Yunnan, China

Science.gov (United States)

Zhang, Chunxia; Guo, Zhengtang; Deng, Chenglong; Ji, Xueping; Wu, Haibin; Paterson, Greig A.; Chang, Lin; Li, Qin; Wu, Bailing; Zhu, Rixiang

2016-01-01

Global and regional environmental changes have influenced the evolutionary processes of hominoid primates, particularly during the Miocene. Recently, a new Lufengpithecus cf. lufengensis hominoid fossil with a late Miocene age of ~6.2 Ma was discovered in the Shuitangba (STB) section of the Zhaotong Basin in Yunnan on the southeast margin of the Tibetan Plateau. To understand the relationship between paleoclimate and hominoid evolution, we have studied sedimentary, clay mineralogy and geochemical proxies for the late Miocene STB section (~16 m thick; ca. 6.7–6.0 Ma). Our results show that Lufengpithecus cf. lufengensis lived in a mildly warm and humid climate in a lacustrine or swamp environment. Comparing mid to late Miocene records from hominoid sites in Yunnan, Siwalik in Pakistan, and tropical Africa we find that ecological shifts from forest to grassland in Siwalik are much later than in tropical Africa, consistent with the disappearance of hominoid fossils. However, no significant vegetation changes are found in Yunnan during the late Miocene, which we suggest is the result of uplift of the Tibetan plateau combined with the Asian monsoon geographically and climatically isolating these regions. The resultant warm and humid conditions in southeastern China offered an important refuge for Miocene hominoids. PMID:26829756

Vegetation and floristics of a lowland tropical rainforest in northeast Australia

Science.gov (United States)

Apgaua, Deborah M. G.; Campbell, Mason J; Cox, Casey J; Crayn, Darren M; Ishida, Françoise Y; Laidlaw, Melinda J; Liddell, Michael J; Seager, Michael; Laurance, Susan G. W.

2016-01-01

Abstract Background Full floristic data, tree demography, and biomass estimates incorporating non-tree lifeforms are seldom collected and reported for forest plots in the tropics. Established research stations serve as important repositories of such biodiversity and ecological data. With a canopy crane setup within a tropical lowland rainforest estate, the 42-ha Daintree Rainforest Observatory (DRO) in Cape Tribulation, northern Australia is a research facility of international significance. We obtained an estimate of the vascular plant species richness for the site, by surveying all vascular plant species from various mature-phase, remnant and open vegetation patches within the site. We also integrate and report the demography and basal areas of trees ≥ 10 cm diameter at breast height (dbh) in a new 1-ha core plot, an extension to the pre-existing forest 1-ha plot under the canopy crane. In addition, we report for the canopy crane plot new demography and basal areas for smaller-size shrubs and treelets subsampled from nine 20 m2 quadrats, and liana basal area and abundance from the whole plot. The DRO site has an estimated total vascular plant species richness of 441 species, of which 172 species (39%) are endemic to Australia, and 4 species are endemics to the Daintree region. The 2 x 1-ha plots contains a total of 262 vascular plant species of which 116 (1531 individuals) are tree species ≥ 10 cm dbh. We estimate a stem basal area of 34.9 m2 ha-1, of which small stems (tree saplings and shrubs rainforests globally, our meta-analysis shows that DRO forests has a comparatively high stem density and moderate species diversity, due to the influence of cyclones. These data will provide an important foundation for ecological and conservation studies in lowland tropical forest. New information We present a floristic checklist, a lifeform breakdown, and demography data from two 1-ha rainforest plots from a lowland tropical rainforest study site. We also present a

Indirect quantification of fine root production in a near tropical wet mountainous region

Science.gov (United States)

Lu, X.; Zhang, J.; Huang, C.

2016-12-01

The main functions of fine root (defined as diameter floristic) and external (environmental) factors into account, including litter production, canopy density (leaf area index), leaf nutrients (N, K, Ca, Mg, P), weather and/or soil physical conditions (air temperature, humidity, precipitation, solar radiation and soil moisture). The study was conducted in near tropical broadleaf (700 m asl) and conifer (1700 m asl) forests in northeastern Taiwan, generally receiving more than 4000 mm of precipitation per year. For each site, 16 50-cm long minirhizotron tubes were installed. Fine root images were acquired every three weeks. Growth and decline, newly presence and absence of fine roots were delineated by image processing algorithms to derive fine-root productivity through time. Aforementioned internal and external attributes were simultaneously collected as well. Some of these variables were highly correlated and were detrended using principal component analysis. We found that these transformed variables (mainly associated with litter production, precipitation and solar radiation) can delineate the spatiotemporal dynamics of root production well (r2 = 0.87, p = 0.443). In conclusion, this study demonstrated the feasibility of utilized aboveground variables to indirectly assess fine root growth, which could be further developed for the regional scale mapping with aid of remote sensing.

Increasing carbon storage in intact African tropical forests

NARCIS (Netherlands)

Lewis, S.L.; Lopez-Gonzalez, G.; Sonké, B.; Affum-Baffoe, K.; Ewango, C.E.N.

2009-01-01

The response of terrestrial vegetation to a globally changing environment is central to predictions of future levels of atmospheric carbon dioxide1, 2. The role of tropical forests is critical because they are carbon-dense and highly productive3, 4. Inventory plots across Amazonia show that

Vegetation Response to Upper Pliocene Glacial/Interglacial Cyclicity in the Central Mediterranean

Science.gov (United States)

Combourieu-Nebout, Nathalie

1993-09-01

New detailed pollen analysis of the lower part of the Upper Pliocene Semaforo section (Crotone, Italy) documents cyclic behavior of vegetation at the beginning of the Northern Hemisphere glaciations. The competition between four vegetation units (subtropical humid forest, deciduous temperate forest, altitudinal coniferous forest, and open xeric assemblage) probably reflects modifications of vegetation belts at this montane site. Several increases in herbaceous open vegetation regularly alternate with subtropical humid forest, which expresses rapid climatic oscillations. The complete temporal succession—deciduous forest (rich in Quercus), followed by subtropical humid forest (Taxodiaceae and Cathaya), then altitudinal coniferous forest ( Tsuga, Cedrus, Abies, and Picea), and finally herbaceous open vegetation (Graminae, Compositae, and Artemisia )—displays the climatic evolution from warm and humid interglaciation to cold and dry glaciation. It also suggests an independent variation of temperature and humidity, the two main climatic parameters. The vegetation history of southern Calabria recorded in the Semaforo section have been correlated with the ∂ 18O signal established in the Atlantic Ocean.

Minerals Masquerading As Enzymes: Abiotic Oxidation Of Soil Organic Matter In An Iron-Rich Humid Tropical Forest Soil

Science.gov (United States)

Hall, S. J.; Silver, W. L.

2010-12-01

Oxidative reactions play an important role in decomposing soil organic matter fractions that resist hydrolytic degradation, and fundamentally affect the cycling of recalcitrant soil carbon across ecosystems. Microbial extracellular oxidative enzymes (e.g. lignin peroxidases and laccases) have been assumed to provide a dominant role in catalyzing soil organic matter oxidation, while other potential oxidative mechanisms remain poorly explored. Here, we show that abiotic reactions mediated by the oxidation of ferrous iron (Fe(II)) could explain high potential oxidation rates in humid tropical forest soils, which often contain high concentrations of Fe(II) and experience rapid redox fluctuations between anaerobic and aerobic conditions. These abiotic reactions could provide an additional mechanism to explain high rates of decomposition in these ecosystems, despite frequent oxygen deficits. We sampled humid tropical forest soils in Puerto Rico, USA from various topographic positions, ranging from well-drained ridges to riparian valleys that experience broad fluctuations in redox potential. We measured oxidative activity by adding the model humic compound L-DOPA to soil slurries, followed by colorimetric measurements of the supernatant solution over time. Dilute hydrogen peroxide was added to a subset of slurries to measure peroxidative activity. We found that oxidative and peroxidative activity correlated positively with soil Fe(II) concentrations, counter to prevailing theory that low redox potential should suppress oxidative enzymes. Boiling or autoclaving sub-samples of soil slurries to denature any enzymes present typically increased peroxidative activity and did not eliminate oxidative activity, further suggesting the importance of an abiotic mechanism. We found substantial differences in the oxidation products of the L-DOPA substrate generated by our soil slurries in comparison with oxidation products generated by a purified enzyme (mushroom tyrosinase

Hydrological drought and wildfire in the humid tropics

NARCIS (Netherlands)

Taufik, Muh

2017-01-01

Drought is a recurrent hazard, which has happened throughout human history, and it is anticipated to become more severe in multiple regions across the world. Drought occurs in all climate regimes from humid to dry and from hot to cold. Drought is often viewed through its impact on environment and

Technical efficiency of irrigated vegetable production among ...

African Journals Online (AJOL)

This study was carried out to analyse the technical efficiency of irrigated vegetable production among smallholder farmers in the guinea savannah, Nigeria, and determine the cost and returns on irrigated vegetable production. Two-stage sampling technique was used, purposive selection of two states and three Local ...

A modelling study of the event-based retention performance of green roof under the hot-humid tropical climate in Kuching.

Science.gov (United States)

Chai, C T; Putuhena, F J; Selaman, O S

2017-12-01

The influences of climate on the retention capability of green roof have been widely discussed in existing literature. However, knowledge on how the retention capability of green roof is affected by the tropical climate is limited. This paper highlights the retention performance of the green roof situated in Kuching under hot-humid tropical climatic conditions. Using the green roof water balance modelling approach, this study simulated the hourly runoff generated from a virtual green roof from November 2012 to October 2013 based on past meteorological data. The result showed that the overall retention performance was satisfactory with a mean retention rate of 72.5% from 380 analysed rainfall events but reduced to 12.0% only for the events that potentially trigger the occurrence of flash flood. By performing the Spearman rank's correlation analysis, it was found that the rainfall depth and mean rainfall intensity, individually, had a strong negative correlation with event retention rate, suggesting that the retention rate increases with decreased rainfall depth. The expected direct relationship between retention rate and antecedent dry weather period was found to be event size dependent.

Terrestrial Water Storage and Vegetation Resilience to Drought

Science.gov (United States)

Meyer, V.; Reager, J. T., II; Konings, A. G.

2017-12-01

The expected increased occurrences of hydrologic extreme events such as droughts in the coming decades motivates studies to better understand and predict the response of vegetation to such extreme conditions. Previous studies have addressed vegetation resilience to drought, defined as its ability to recover from a perturbation (Hirota et al., 2011; Vicente-Serrano et al., 2012), but appear to only focus on precipitation and a couple of vegetation indices, hence lacking a key element: terrestrial water storage (TWS). In this study, we combine and compare multiple remotely-sensed hydro-ecological datasets providing information on climatic and hydrological conditions (Tropical Rainfall Measuring Mission (TRMM), Gravity Recovery and Climate Experiment (GRACE)) and indices characterizing the state of the vegetation (vegetation water content using Vegetation Optical Depth (VOD) from SMAP (Soil Moisture Active and Passive), Gross Primary Production (GPP) from FluxCom and Specific Fluorescence Intensity (SFI, from GOSat)) to assess the ability of vegetation to face and recover from droughts across the globe. Our results suggest that GRACE hydrological data bridge the knowledge gap between precipitation deficit and vegetation response. All products are aggregated at a 0.5º spatial resolution and a monthly temporal resolution to match the GRACE Mascon product. Despite these coarse spatiotemporal resolutions, we find that the relationship between existing remotely-sensed eco-hydrologic data varies spatially, both in terms of strength of relationship and time lag, showing the response time of vegetation characteristics to hydrological changes and highlighting the role of water storage. A special attention is given to the Amazon river basin, where two well documented droughts occurred in 2005 and 2010, and where a more recent drought occurred in 2015/2016. References : Hirota, Marina, et al. "Global resilience of tropical forest and savanna to critical transitions." Science

Effects of tropical montane forest disturbance on epiphytic macrolichens

Energy Technology Data Exchange (ETDEWEB)

Benitez, Angel [Instituto de Ecologia, Herbario HUTPL, Universidad Tecnica Particular de Loja, San Cayetano s/n, Loja (Ecuador); Prieto, Maria, E-mail: maria.prieto@urjc.es [Area de Biodiversidad y Conservacion, ESCET, Universidad Rey Juan Carlos, Mostoles, E-28933, Madrid (Spain); Gonzalez, Yadira [Instituto de Ecologia, Herbario HUTPL, Universidad Tecnica Particular de Loja, San Cayetano s/n, Loja (Ecuador); Aragon, Gregorio [Area de Biodiversidad y Conservacion, ESCET, Universidad Rey Juan Carlos, Mostoles, E-28933, Madrid (Spain)

2012-12-15

The high diversity of epiphytes typical of undisturbed montane tropical forests has been negatively affected by continuous deforestation and forest conversion to secondary vegetation. Macrolichens are an important component of these epiphytes. Because their physiology is strongly coupled to humidity and solar radiation, we hypothesized that microclimatic changes derived from forest clearing and logging can affect the diversity of these poikilohydric organisms. In southern Ecuador, we examined three types of forests according to a disturbance gradient (primary forests, secondary forests, and monospecific forests of Alnus acuminata) for the presence/absence and coverage of epiphytic macrolichens that we identified on 240 trees. We found that total richness tended to decrease when the range of the disturbance increased. The impoverishment was particularly drastic for 'shade-adapted lichens', while the richness of 'heliophytic lichens' increased in the drier conditions of secondary growth. Epiphytic composition also differed significantly among the three types of forests, and the similarity decreased when the range of the disturbance was greater. We concluded that a span of 40 years of recovery by secondary vegetation was not enough to regenerate the diversity of epiphytic macrolichens that was lost due to forest disturbances. -- Highlights: Black-Right-Pointing-Pointer Tropical montane forest disturbance drastically reduced macrolichen diversity. Black-Right-Pointing-Pointer Species loss was most severe for the 'shade-adapted lichens' because high radiation is harmful to them. Black-Right-Pointing-Pointer In secondary forests lichen diversity of native forests was not regenerated. Black-Right-Pointing-Pointer The protection of remnants of primary tropical forest might help to preserve a diverse community of epiphytic macrolichens.

Mycotoxin production in wheat grains by different Aspergilli in relation to different relative humidities and storage periods.

Science.gov (United States)

Atalla, Mohamed Mabrouk; Hassanein, Naziha Mohamed; El-Beih, Ahmed Atef; Youssef, Youssef Abdel-ghany

2003-02-01

Four different Aspergilli (Aspergillus oryzae, A. parasiticus, A. terreus and A. versicolor) were grown on wheat grains underdifferent degrees of relative humidity 14, 50, 74, 80 and 90%. Samples of wheat grains were taken monthly for a period of six months and examined for mycotoxin production. A. oryzae was found to produce aflatoxins B1, B2, zearalenone, DON and T-2 toxins under elevated degrees of humidity and prolonged periods of storage. A. parasiticus produced aflatoxins B1, G1, NIV, DON and T-2 toxins in high concentrations during a period of not more than three months storage at 14% relative humidity; at an increased level of relative humidity of 74% ochratoxin A, zearalenone and sterigmatocystin were also produced at high levels. The isolate was drastic in toxin production. A. terrus produced toxins at 14% relative humidity (aflatoxin G2 and DON) at levels much higher than any other prevalent degrees of humidity. A. versicolor is highly sensitive to relative humidity and grain moisture content It produced aflatoxins B1, G1, NIV and DON at a relative humidity of 50% and another toxins (aflatoxin G2, ochratoxins A, B and zearalenone) at 74%. The microorganism can be considered a trichothecene producer under suitable relative humidity.

Late Glacial Tropical Savannas in Sundaland Inferred From Stable Carbon Isotope Records of Cave Guano

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Wurster, C. M.; Bird, M. I.; Bull, I.; Dungait, J.; Bryant, C. L.; Ertunç, T.; Hunt, C.; Lewis, H. A.; Paz, V.

2008-12-01

During the Last Glacial Period (LGP), reduced global sea level exposed the continental shelf south of Thailand to Sumatra, Java, and Borneo to form the contiguous continent of Sundaland. However, the type and extent of vegetation that existed on much of this exposed landmass during the LGP remains speculative. Extensive bird and bat guano deposits in caves throughout this region span beyond 40,000 yr BP, and contain a wealth of untapped stratigraphic palaeoenvironmental information. Stable carbon isotope ratios of insectivorous bird and bat guano contain a reliable record of the animal's diet and, through non-specific insect predation, reflect the relative abundance of major physiological pathways in plants. Various physiological pathways of carbon fixation in plants yield differing stable carbon isotope ratios. Stable carbon isotope values of C3 plants are lower than C4 vegetation due to different enzymatic discriminations of the heavy isotope through the carbon fixing pathways. In tropical locales, grasses nearly always follow the C4 photosynthetic pathway, whereas tropical rainforest uses C3 photosynthesis, providing a proxy for vegetation and therefore climate change in the past. Here we discuss four guano stable-isotope records, based on insect cuticle and n-alkane analysis, supplemented by pollen analysis. All sites suggest a C3 dominated ecosystem for the Holocene, consistent with the wet tropical forest vegetation present at all locations. Two sites from Palawan Island, Philippines, record stable carbon isotope values of guano that document a drastic change from C3 (forest) to C4 (savanna) dominated ecosystems during the Last Glacial Maximum (LGM). A third location, at Niah Great Cave, Malaysia, indicates C3-dominant vegetation throughout the record, but does display variation in stable carbon isotope values likely linked to humidity changes. A fourth location, Batu Caves in Peninsular Malaysia, also indicates open vegetation during the LGM. Vegetation

Energy and cost associated with ventilating office buildings in a tropical climate.

Science.gov (United States)

Rim, Donghyun; Schiavon, Stefano; Nazaroff, William W

2015-01-01

Providing sufficient amounts of outdoor air to occupants is a critical building function for supporting occupant health, well-being and productivity. In tropical climates, high ventilation rates require substantial amounts of energy to cool and dehumidify supply air. This study evaluates the energy consumption and associated cost for thermally conditioning outdoor air provided for building ventilation in tropical climates, considering Singapore as an example locale. We investigated the influence on energy consumption and cost of the following factors: outdoor air temperature and humidity, ventilation rate (L/s per person), indoor air temperature and humidity, air conditioning system coefficient of performance (COP), and cost of electricity. Results show that dehumidification of outdoor air accounts for more than 80% of the energy needed for building ventilation in Singapore's tropical climate. Improved system performance and/or a small increase in the indoor temperature set point would permit relatively large ventilation rates (such as 25 L/s per person) at modest or no cost increment. Overall, even in a thermally demanding tropical climate, the energy cost associated with increasing ventilation rate up to 25 L/s per person is less than 1% of the wages of an office worker in an advanced economy like Singapore's. This result implies that the benefits of increasing outdoor air ventilation rate up to 25 L/s per person--which is suggested to provide for productivity increases, lower sick building syndrome symptom prevalence, and reduced sick leave--can be much larger than the incremental cost of ventilation.

Night ventilation at courtyard housing estate in warm humid tropic for sustainable environment

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Defiana, Ima; Teddy Badai Samodra, FX; Setyawan, Wahyu

2018-03-01

The problem in the night-time for warm humid tropic housing estate is thermal discomfort. Heat gains accumulation from building envelope, internal heat gains and activities of occupants influence indoor thermal comfort. Ventilation is needed for transfer or removes heat gains accumulation to outdoor. This study describes the role of an inner courtyard to promote pressure difference. Pressure difference as a wind driven force to promote wind velocity thereby could transfer indoor heat gains accumulation to outdoor of building. A simulation used as the research method for prediction wind velocity. Purposive sampling used as the method to choose building sample with similar inner courtyards. The field survey was conducted to obtain data of inner courtyard typologies and two housing were used as model simulation. Furthermore, the simulation is running in steady state mode, at 05.00 pm when the occupants usually close window. But the window should be opened in the night-time to transfer indoor heat gain to outdoor. The result shows that the factor influencing physiological cooling as consequences of inner courtyard are height to width ratio, the distance between inner courtyard to windward, window configuration and the inner courtyard design-the proportion between the length, the width, and the height.

Evaluating the coupled vegetation-fire model, LPJ-GUESS-SPITFIRE, against observed tropical forest biomass

Science.gov (United States)

Spessa, Allan; Forrest, Matthew; Werner, Christian; Steinkamp, Joerg; Hickler, Thomas

2013-04-01

Wildfire is a fundamental Earth System process. It is the most important disturbance worldwide in terms of area and variety of biomes affected; a major mechanism by which carbon is transferred from the land to the atmosphere (2-4 Pg per annum, equiv. 20-30% of global fossil fuel emissions over the last decade); and globally a significant source of particulate aerosols and trace greenhouse gases. Fire is also potentially important as a feedback in the climate system. If climate change favours more intense fire regimes, this would result in a net transfer of carbon from ecosystems to the atmosphere, as well as higher emissions, and under certain circumstances, increased troposphere ozone production- all contributing to positive climate-land surface feedbacks. Quantitative analysis of fire-vegetation-climate interactions has been held back until recently by a lack of consistent global data sets on fire, and by the underdeveloped state of dynamic vegetation-fire modelling. Dynamic vegetation-fire modelling is an essential part of our forecasting armory for examining the possible impacts of climate, fire regimes and land-use on ecosystems and emissions from biomass burning beyond the observation period, as part of future climate or paleo-climate studies. LPJ-GUESS is a process-based model of vegetation dynamics designed for regional to global applications. It combines features of the Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ-DGVM) with those of the General Ecosystem Simulator (GUESS) in a single, flexible modelling framework. The models have identical representations of eco-physiological and biogeochemical processes, including the hydrological cycle. However, they differ in the detail with which vegetation dynamics and canopy structure are simulated. Simplified, computationally efficient representations are used in the LPJ-DGVM, while LPJ-GUESS employs a gap-model approach, which better captures ecological succession and hence ecosystem changes due to

Genotype-environment interaction of maternal influence characteristics in Nellore cattle bred in the Brazilian humid tropical regions by reaction norm

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Jorge Luís Ferreira

2015-08-01

Full Text Available Reaction Norm (RN is the study of genotype-environment interaction (GxE that complies with alternative ways of genotypes within different environments. This study was carried out to verify GxE by a reaction norm model of weights at 120 (W120 and 210 (W210 days of age in Nellore cattle raised in the Humid Tropical Regions of Brazil. Environmental gradients were obtained by solutions of contemporary groups which were fitted as co-variables in the random regression model via reaction norms. Mean weight at 120 days of age was 127.97 kg, and environmental gradients ranged between -27 and +26 kg. Average was 185.60 kg at 210 days of age and gradients ranged from -54 to +55 kg. Scale changes in the breeding values and heritability estimates occurred along the gradients for the two weights; the genetic correlations between breeding value breeding values were also similar for both weights. These correlations were high between the close gradients, and low to even negative between extreme environments. Slopes representing the environmental sensitivity were high, with changes of scale and changes in classification of ten bulls with a great numbers of calves for the two traits. When regression slopes of the ten bulls with the highest breeding value breeding values were evaluated, these values were different in W120 from those in W210, perhaps due to the greater influence of maternal effect on W120. These results characterize the influence of GxE on the pre-weaning weights of animals in the humid tropical regions of Brazil. Due to this, it is possible to get greater precision on the predictions of the animals breeding values breeding value. A less biased selection and a greater genetic progress occurred.

Pennsylvanian coniferopsid forests in sabkha facies reveal the nature of seasonal tropical biome

Science.gov (United States)

Falcon-Lang, H. J.; Jud, N.A.; John, Nelson W.; DiMichele, W.A.; Chaney, D.S.; Lucas, S.G.

2011-01-01

Pennsylvanian fossil forests are known from hundreds of sites across tropical Pangea, but nearly all comprise remains of humid Coal Forests. Here we report a unique occurrence of seasonally dry vegetation, preserved in growth position along >5 km of strike, in the Pennsylvanian (early Kasimovian, Missourian) of New Mexico (United States). Analyses of stump anatomy, diameter, and spatial density, coupled with observations of vascular traces and associated megaflora, show that this was a deciduous, mixed-age, coniferopsid woodland (~100 trees per hectare) with an open canopy. The coniferopsids colonized coastal sabkha facies and show tree rings, confirming growth under seasonally dry conditions. Such woodlands probably served as the source of coniferopsids that replaced Coal Forests farther east in central Pangea during drier climate phases. Thus, the newly discovered woodland helps unravel biome-scale vegetation dynamics and allows calibration of climate models. ?? 2011 Geological Society of America.

Relative Humidity in the Tropopause Saturation Layer

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Selkirk, H. B.; Schoeberl, M. R.; Pfister, L.; Thornberry, T. D.; Bui, T. V.

2017-12-01

The tropical tropopause separates two very different atmospheric regimes: the stable lower stratosphere where the air is both extremely dry and nearly always so, and a transition layer in the uppermost tropical troposphere, where humidity on average increases rapidly downward but can undergo substantial temporal fluctuations. The processes that control the humidity in this layer below the tropopause include convective detrainment (which can result in either a net hydration or dehydration), slow ascent, wave motions and advection. Together these determine the humidity of the air that eventually passes through the tropopause and into the stratosphere, and we refer to this layer as the tropopause saturation layer or TSL. We know from in situ water vapor observations such as Ticosonde's 12-year balloonsonde record at Costa Rica that layers of supersaturation are frequently observed in the TSL. While their frequency is greatest during the local rainy season from June through October, supersaturation is also observed in the boreal winter dry season when deep convection is well south of Costa Rica. In other words, local convection is not a necessary condition for the presence of supersaturation. Furthermore, there are indications from airborne measurements during the recent POSIDON campaign at Guam that if anything deep convection tends to `reset' the TSL locally to a state of just-saturation. Conversely, it may be that layers of supersaturation are the result of slow ascent. To explore these ideas we take Ticosonde water vapor observations from the TSL, stratify them on the basis of relative humidity and report on the differences in the the history of upstream convective influence between supersaturated parcels and those that are not.

Field vegetable production in the Lake Zone of Tanzania

NARCIS (Netherlands)

Everaarts, A.P.; Putter, de H.; Maerere, A.P.; Amon, W.

2014-01-01

In November 2012 and in August 2014 surveys were carried out in field vegetable producing areas in the Lake Zone of Tanzania. The aim of the surveys was to learn the conditions for field vegetable production and marketing in these areas. Recommendations for the development of vegetable production

On the development of a coupled regional climate-vegetation model RCM-CLM-CN-DV and its validation in Tropical Africa

Science.gov (United States)

Wang, Guiling; Yu, Miao; Pal, Jeremy S.; Mei, Rui; Bonan, Gordon B.; Levis, Samuel; Thornton, Peter E.

2016-01-01

This paper presents a regional climate system model RCM-CLM-CN-DV and its validation over Tropical Africa. The model development involves the initial coupling between the ICTP regional climate model RegCM4.3.4 (RCM) and the Community Land Model version 4 (CLM4) including models of carbon-nitrogen dynamics (CN) and vegetation dynamics (DV), and further improvements of the models. Model improvements derive from the new parameterization from CLM4.5 that addresses the well documented overestimation of gross primary production (GPP), a refinement of stress deciduous phenology scheme in CN that addresses a spurious LAI fluctuation for drought-deciduous plants, and the incorporation of a survival rule into the DV model to prevent tropical broadleaf evergreens trees from growing in areas with a prolonged drought season. The impact of the modifications on model results is documented based on numerical experiments using various subcomponents of the model. The performance of the coupled model is then validated against observational data based on three configurations with increasing capacity: RCM-CLM with prescribed leaf area index and fractional coverage of different plant functional types (PFTs); RCM-CLM-CN with prescribed PFTs coverage but prognostic plant phenology; RCM-CLM-CN-DV in which both the plant phenology and PFTs coverage are simulated by the model. Results from these three models are compared against the FLUXNET up-scaled GPP and ET data, LAI and PFT coverages from remote sensing data including MODIS and GIMMS, University of Delaware precipitation and temperature data, and surface radiation data from MVIRI and SRB. Our results indicate that the models perform well in reproducing the physical climate and surface radiative budgets in the domain of interest. However, PFTs coverage is significantly underestimated by the model over arid and semi-arid regions of Tropical Africa, caused by an underestimation of LAI in these regions by the CN model that gets exacerbated

Vegetation structure of plantain-based agrosystems determines numerical dominance in community of ground-dwelling ants.

Science.gov (United States)

Dassou, Anicet Gbéblonoudo; Tixier, Philippe; Dépigny, Sylvain; Carval, Dominique

2017-01-01

In tropics, ants can represent an important part of animal biomass and are known to be involved in ecosystem services, such as pest regulation. Understanding the mechanisms underlying the structuring of local ant communities is therefore important in agroecology. In the humid tropics of Africa, plantains are cropped in association with many other annual and perennial crops. Such agrosystems differ greatly in vegetation diversity and structure and are well-suited for studying how habitat-related factors affect the ant community. We analysed abundance data for the six numerically dominant ant taxa in 500 subplots located in 20 diversified, plantain-based fields. We found that the density of crops with foliage at intermediate and high canopy strata determined the numerical dominance of species. We found no relationship between the numerical dominance of each ant taxon with the crop diversity. Our results indicate that the manipulation of the densities of crops with leaves in the intermediate and high strata may help maintain the coexistence of ant species by providing different habitat patches. Further research in such agrosystems should be performed to assess if the effect of vegetation structure on ant abundance could result in efficient pest regulation.

Management of tropical forests for products and energy

Science.gov (United States)

John I. Zerbe

1992-01-01

Tropical forests have always been sources for prized timbers, rubber, tannin, and other forest products for use worldwide. However, with the recent concern regarding global change, the importance of effective forest products management and utilization has increased significantly. The USDA Forest Service's Forest Products Laboratory at Madison, Wisconsin, has...

Energy use pattern analyses of greenhouse vegetable production

Energy Technology Data Exchange (ETDEWEB)

Canakci, M.; Akinci, I. [Department of Agricultural Machinery, Faculty of Agriculture, Akdeniz University, 07070 Antalya (Turkey)

2006-07-15

Greenhouse farming is a growing industry in many states. It is a very expensive way to produce greenhouse crops and there are many variables to consider before the farmer decides to take this route. A good location is essential for crop planning and growing. However, current studies related to energy use patterns and resources present in vegetable production are very limited. This research attempts to investigate the energy use patterns in greenhouse vegetable production, to determine the energy output-input ratio and their relationships. Antalya province, which has greenhouse area of about 13,337ha (30.2%), is the center of greenhouse farming in Turkey. A questionnaire was distributed to 101 greenhouse farms from 11 villages in order to obtain the available data for vegetable production. Power requirement of the machines used in greenhouse operations were measured by using a computer based data acquisition system. Energy and economical variables (i.e. output-input ratio, specific energy, production cost, net return, etc.) were calculated by using the standard equations. As a result, the operational energy and energy source requirements of the greenhouse vegetable production were found between the ranges of 23,883.5-28,034.7 and 45,763.3-49,978.8MJ/1000m{sup 2}, respectively. The energy ratio of four major greenhouse vegetables-tomato, pepper, cucumber and eggplant-was 0.32, 0.19, 0.31, 0.23, respectively. The crop yields increased as a function of the total energy inputs with the best form being second-degree polynomial. The net return of the vegetable production was found in the 595.6-2775.3$/1000m{sup 2} ranges. Among the greenhouse vegetables, tomato cultivation resulted in being the most profitable. (author)

Potential and Limitations of Low-Cost Unmanned Aerial Systems for Monitoring Altitudinal Vegetation Phenology in the Tropics

Science.gov (United States)

Silva, T. S. F.; Torres, R. S.; Morellato, P.

2017-12-01

Vegetation phenology is a key component of ecosystem function and biogeochemical cycling, and highly susceptible to climatic change. Phenological knowledge in the tropics is limited by lack of monitoring, traditionally done by laborious direct observation. Ground-based digital cameras can automate daily observations, but also offer limited spatial coverage. Imaging by low-cost Unmanned Aerial Systems (UAS) combines the fine resolution of ground-based methods with and unprecedented capability for spatial coverage, but challenges remain in producing color-consistent multitemporal images. We evaluated the applicability of multitemporal UAS imaging to monitor phenology in tropical altitudinal grasslands and forests, answering: 1) Can very-high resolution aerial photography from conventional digital cameras be used to reliably monitor vegetative and reproductive phenology? 2) How is UAS monitoring affected by changes in illumination and by sensor physical limitations? We flew imaging missions monthly from Feb-16 to Feb-17, using a UAS equipped with an RGB Canon SX260 camera. Flights were carried between 10am and 4pm, at 120-150m a.g.l., yielding 5-10cm spatial resolution. To compensate illumination changes caused by time of day, season and cloud cover, calibration was attempted using reference targets and empirical models, as well as color space transformations. For vegetative phenological monitoring, multitemporal response was severely affected by changes in illumination conditions, strongly confounding the phenological signal. These variations could not be adequately corrected through calibration due to sensor limitations. For reproductive phenology, the very-high resolution of the acquired imagery allowed discrimination of individual reproductive structures for some species, and its stark colorimetric differences to vegetative structures allowed detection of the reproductive timing on the HSV color space, despite illumination effects. We conclude that reliable

Importance of silvopastoral systems on caloric stress reduction in tropical livestock productions

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Alexander Navas Panadero

2010-06-01

Full Text Available Livestock systems in Colombia have been developed taking concepts and technologies from the green revolution, where gramineous monocrop is privileged over arboreal cover in grazing lands. This model has not taken into account the climatic conditions of the different tropical ecosystems, in which variables as temperature, relative humidity and evaporation can limit the animal´s productive and reproductive efficiency, besides being a risk factor for illness occurrence in the herd. Bos Taurus and Bos Indicus breeds show termoneutral ranges where its genetic potential can be express. However, out of this comfort area animals can enter in caloric stress which in consequence reduces its performance and sometimes can end up causing death. Silvopastoral systems comprise several functions; it contributes to lessen caloric stress since temperature under the tree canopy can reach between 2 and 9°C lower in comparison to open pastures. Differences in temperature reduction have been found among silvopastoral systems and species, being the tree group arrangements and the species with high density canopy, those with superior effect. Interactions among components should be analyzed in order to design systems that incorporate enough arboreal cover to achieve caloric stress reductions, but without affecting forage production in pastures. Silvopastoral systems contribute to improve animal welfare.

Whey protein concentrate storage at elevated temperature and humidity

Science.gov (United States)

Dairy processors are finding new export markets for whey protein concentrate (WPC), a byproduct of cheesemaking, but they need to know if full-sized bags of this powder will withstand high temperature and relative humidity (RH) levels during unrefrigerated storage under tropical conditions. To answ...

Ultrasonic characterization of vegetable oil product

International Nuclear Information System (INIS)

Sidek Hj Abd Aziz; Chow Sai Pew; Abdul Halim Shaari; Nor Azizah Shaari

1992-01-01

The ultrasonic wave velocity and attenuation of a number vegetable oil products were measured using an ultrasonic pulse echo overlap technique from room temperature up to 90 0 C. Among the liquid samples studied were refined bleach deodorized (RED) palm oil, palm olein, coconut oil, corn oil and soya bean oil. The velocity of sound in vegetable oil products varies from about 1200 to 200 ms-1 and decrease linearly as the temperature increases. The ultrasonic properties of the oil are much dependent on their viscosity, density, relaxation effect and vibrational anharmonicity

Test Operations Procedure (TOP) 01-1-020 Tropical Regions Environmental Considerations

Science.gov (United States)

2013-02-08

to exude tannins , sugars, and other natural plant products, which may support microbial growth and corrosion processes. 2.2 Test Site Severity...Containers in Humid Environments, US Army Tropic Test Center, TECOM Project No. 7-C0-PB5-TT1-004, 1978. 16. A Technical Analysis to Identify Ideal...1973. 37. MIL-STD-810G, Test Method Standard, Environmental Engineering Considerations and Laboratory Tests, 2008. 38. A Technical Analysis

An analysis of tropical hardwood product importation and consumption in the United States

Science.gov (United States)

Paul M. Smith; Michael P. Haas; William G. Luppold; William G. Luppold

1995-01-01

The consumption of forest products emanating from tropical rainforests is an issue that is receiving increasing attention in the United States. This attention stems from concerns over the sustainability of tropical ecosystems. However, trade statistics show the United States imported only 4.0 percent of all tropical timber products traded globally in 1989. In addition...

The technology of fish-vegetable feed production

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Mukatova M. D.

2016-09-01

Full Text Available Perspective direction of the Volga-Caspian basin fisheries is increasing the productivity of aquaculture production which requires the availability of sufficient quantities of feed. The cutting waste of carp and crucian carp, crayfish processing (cephalothorax, wheat bran, soy isolate, freshwater plants – pondweed perfoliate, fish-vegetable ration, produced feeding staffs have been investigated. In researching samples of manufactured pelleted feeds the standard methods adopted in the animal feed industry have been used. The number of nitrogen-free extractives and energy value has been determined by calculation. The composition of fish-vegetable ration has been worked out. Some manufacturing inspection of fish-vegetable feed technology using proofing process has been carried out. The possibility of manufacturing on the basis of crushed fish waste of the company LLC "VES" and dry ingredients of fish-vegetable feed has been determined; the output of feed at water content of not more than 10 % is 43 % of feed mix based on the mass of directed waste equal to 84 %. The pilot batch of dry fish-vegetable feed has been investigated to establish quality indicators. It has been determined that fish-vegetable feed meets the requirements of GOST 10385–2014 "Combined feeding staffs for fishes. General specifications" as for main quality indicators and refers to economic grower for catfish and carp fish weighing more than 50 g. This reveals good palatability of the experimental batch of floating feed by carp fish species and African catfish. Thus, fish-vegetable feed manufacturing technology can be implemented in the production for processing secondary raw materials: waste from butchering fish by grinding, cooking, mixing with selected vegetable fillings which is waste of flour or grain processing industries and freshwater plants mowed annually during the reclamation works on the Volga delta.

Multivariate analysis of effects of diurnal temperature and seasonal humidity variations by tropical savanna climate on the emissions of anthropogenic volatile organic compounds.

Science.gov (United States)

Liu, Chih-Chung; Chen, Wei-Hsiang; Yuan, Chung-Shin; Lin, Chitsan

2014-02-01

Volatile organic compounds (VOCs), particularly those from anthropogenic sources, have been of substantial concern. In this study, the influences of diurnal temperature and seasonal humidity variations by tropical savanna climate on the distributions of VOCs from stationary industrial sources were investigated by analyzing the concentrations during the daytime and nighttime in the dry and wet seasons and assessing the results by principal component analysis (PCA) and cluster analysis. Kaohsiung City in Southern Taiwan, known for its severe VOC pollution, was chosen as the location to be examined. In the results, the VOC concentrations were lower during the daytime and in the wet season, possibly attributed to the stronger photochemical reactions and increasing inhibition of VOC emissions and transports by elevating humidity levels. Certain compounds became appreciably more important at higher humidity, as these compounds were saturated hydrocarbons with relatively low molecular weights. The influence of diurnal temperature variation on VOC distribution behaviors seemed to be less important than and interacted with that of seasonal humidity variation. Heavier aromatic hydrocarbons with more complex structures and some aliphatic compounds were found to be the main species accounting for the maximum variances of the data observed at high humidity, and the distinct grouping of compounds implied a pronounced inherent characteristic of each cluster in the observed VOC distributions. Under the influence of diurnal temperature variation, selected VOCs that may have stronger photochemical resistances and/or longer lifetimes in the atmosphere were clustered with each other in the cluster analysis, whereas the other groups might consist of compounds with different levels of vulnerability to sunlight or high temperatures. These findings prove the complications in the current knowledge regarding the VOC contaminations and providing insight for managing the adverse impacts of

Effects of relative humidity, temperature, and population density on production of cuticular hydrocarbons in housefly Musca domestica L.

NARCIS (Netherlands)

Noorman, N; Den Otter, CJ

The production of cuticular hydrocarbons by both males and females of Musca domestica L. under very wet conditions (90% relative humidity) compared to the production at 50 and 20% relative humidity is delayed up to at least 3 days after emergence from the pupae. Eight days after emergence, however,

Abiotic factors influencing tropical dry forests regeneration

Directory of Open Access Journals (Sweden)

Ceccon Eliane

2006-01-01

Full Text Available Tropical dry forests represent nearly half the tropical forests in the world and are the ecosystems registering the greatest deterioration from the anthropogenic exploitation of the land. This paper presents a review on the dynamics of tropical dry forests regeneration and the main abiotic factors influencing this regeneration, such as seasonal nature, soil fertility and humidity, and natural and anthropic disturbances. The main purpose is to clearly understand an important part of TDF succession dynamics.

On the comparisons of tropical relative humidity in the lower and middle troposphere among COSMIC radio occultations, MERRA and ECMWF data sets

Science.gov (United States)

Vergados, P.; Mannucci, A. J.; Ao, C. O.; Jiang, J. H.; Su, H.

2015-01-01

The spatial variability of the tropical tropospheric relative humidity (RH) throughout the vertical extent of the troposphere is examined using Global Positioning System Radio Occultation (GPSRO) observations from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) mission. These high vertical resolution observations capture the detailed structure and moisture budget of the Hadley Cell circulation. We compare the COSMIC observations with the European Center for Medium-range Weather Forecast (ECMWF) Re-Analysis Interim (ERA-Interim) and the Modern-Era Retrospective analysis for Research and Applications (MERRA) climatologies. Qualitatively, the spatial pattern of RH in all data sets matches up remarkably well, capturing distinct features of the general circulation. However, RH discrepancies exist between ERA-Interim and COSMIC data sets, which are noticeable across the tropical boundary layer. Specifically, ERA-Interim shows a drier Inter Tropical Convergence Zone (ITCZ) by 15-20% compared both to COSMIC and MERRA data sets, but this difference decreases with altitude. Unlike ECMWF, MERRA shows an excellent agreement with the COSMIC observations except above 400 hPa, where GPSRO observations capture drier air by 5-10%. RH climatologies were also used to evaluate intraseasonal variability. The results indicate that the tropical middle troposphere at ±5-25° is most sensitive to seasonal variations. COSMIC and MERRA data sets capture the same magnitude of the seasonal variability, but ERA-Interim shows a weaker seasonal fluctuation up to 10% in the middle troposphere inside the dry air subsidence regions of the Hadley Cell. Over the ITCZ, RH varies by maximum 9% between winter and summer.

Desorption isotherms of heavy (AZOBE, EBONY) and light heavyweight tropical woods (IROKO, SAPELLI) of Cameroon

Science.gov (United States)

Nsouandélé, J. L.; Tamba, J. G.; Bonoma, B.

2018-04-01

This work is centered on the study of the desorption isotherms of heavy (Azobe, Ebony) and heavyweight (Iroko, Sapelli) tropical woods, which contribute in the determination of drying and storage of tropical plank woods. Desorption isotherms of tropical woods were experimentally determined under different temperatures in this study using the gravimetric method. The determination of Henderson's model isotherms parameters of desorption were obtained for temperatures of 20 °C, 30 °C, 40 °C, and 50 °C. The mean relative deviation between theoretical and experimental moisture contents was calculated and fitted well with the desorption models of tropical woods. We noticed that Henderson models fitted much better with experimental ones for 95% of relative humidity. The sigmoid shapes of results are satisfactory. Hysteresis phenomenon was observed for desorption isotherms of heavy (Azobe, Ebony) and heavyweight (Iroko, Sapelli) tropical woods. Results showed the difference between the stability and use of heavy and heavyweight tropical wood. These results help in the estimation of water content at equilibrium of tropical woods in relative humidity from experimented ones. Hygroscopic equilibrium humidity of heavy tropical woods varied between 0% and 50% while those of heavyweight varied between 0% and 25%. Therefore, these woods can be used in an opened environment; woodwork and decoration.

On the potential of long wavelength imaging radars for mapping vegetation types and woody biomass in tropical rain forests

Science.gov (United States)

Rignot, Eric J.; Zimmermann, Reiner; Oren, Ram

1995-01-01

In the tropical rain forests of Manu, in Peru, where forest biomass ranges from 4 kg/sq m in young forest succession up to 100 kg/sq m in old, undisturbed floodplain stands, the P-band polarimetric radar data gathered in June of 1993 by the AIRSAR (Airborne Synthetic Aperture Radar) instrument separate most major vegetation formations and also perform better than expected in estimating woody biomass. The worldwide need for large scale, updated biomass estimates, achieved with a uniformly applied method, as well as reliable maps of land cover, justifies a more in-depth exploration of long wavelength imaging radar applications for tropical forests inventories.

Synergistic interactions within disturbed habitats between temperature, relative humidity and UVB radiation on egg survival in a diadromous fish.

Directory of Open Access Journals (Sweden)

Michael J H Hickford

Full Text Available Anthropogenic impacts, including urbanization, deforestation, farming, and livestock grazing have altered riparian margins worldwide. One effect of changes to riparian vegetation is that the ground-level light, temperature, and humidity environment has also been altered. Galaxias maculatus, one of the most widely distributed fishes of the southern hemisphere, lays eggs almost exclusively beneath riparian vegetation in tidally influenced reaches of rivers. We hypothesized that the survival of these eggs is greatly affected by the micro-environment afforded by vegetation, particularly relating to temperature, humidity and UVB radiation. We experimentally reduced riparian vegetation height and altered shading characteristics, tracked egg survival, and used small ground-level temperature, humidity and UVB sensors to relate survival to ground-level effects around egg masses. The ground-level physical environment was markedly different from the surrounding ambient conditions. Tall dense riparian vegetation modified ambient conditions to produce a buffered temperature regime with constant high relative humidity, generally above 90%, and negligible UVB radiation at ground-level. Where vegetation height was reduced, frequent high temperatures, low humidity, and high UVB irradiances reduced egg survival by up to 95%. Temperature effects on egg survival were probably indirect, through reduced humidity, because developing eggs are known to survive in a wide range of temperatures. In this study, it was remarkable how such small variations in relatively small sites could have such a large effect on egg survival. It appears that modifications to riparian vegetation and the associated changes in the physical conditions of egg laying sites are major mechanisms affecting egg survival. The impacts associated with vegetational changes through human-induced disturbances are complex yet potentially devastating. These effects are particularly important because they

Attribution of observed surface humidity changes to human influence.

Science.gov (United States)

Willett, Katharine M; Gillett, Nathan P; Jones, Philip D; Thorne, Peter W

2007-10-11

Water vapour is the most important contributor to the natural greenhouse effect, and the amount of water vapour in the atmosphere is expected to increase under conditions of greenhouse-gas-induced warming, leading to a significant feedback on anthropogenic climate change. Theoretical and modelling studies predict that relative humidity will remain approximately constant at the global scale as the climate warms, leading to an increase in specific humidity. Although significant increases in surface specific humidity have been identified in several regions, and on the global scale in non-homogenized data, it has not been shown whether these changes are due to natural or human influences on climate. Here we use a new quality-controlled and homogenized gridded observational data set of surface humidity, with output from a coupled climate model, to identify and explore the causes of changes in surface specific humidity over the late twentieth century. We identify a significant global-scale increase in surface specific humidity that is attributable mainly to human influence. Specific humidity is found to have increased in response to rising temperatures, with relative humidity remaining approximately constant. These changes may have important implications, because atmospheric humidity is a key variable in determining the geographical distribution and maximum intensity of precipitation, the potential maximum intensity of tropical cyclones, and human heat stress, and has important effects on the biosphere and surface hydrology.

Combustion of animal or vegetable based liquid waste products

International Nuclear Information System (INIS)

Wikman, Karin; Berg, Magnus

2002-04-01

In this project experiences from combustion of animal and vegetable based liquid waste products have been compiled. Legal aspects have also been taken into consideration and the potential for this type of fuel on the Swedish energy market has been evaluated. Today the supply of animal and vegetable based liquid waste products for energy production in Sweden is limited. The total production of animal based liquid fat is about 10,000 tonnes annually. The animal based liquid waste products origin mainly from the manufacturing of meat and bone meal. Since meat and bone meal has been banned from use in animal feeds it is possible that the amount of animal based liquid fat will decrease. The vegetable based liquid waste products that are produced in the processing of vegetable fats are today used mainly for internal energy production. This result in limited availability on the commercial market. The potential for import of animal and vegetable based liquid waste products is estimated to be relatively large since the production of this type of waste products is larger in many other countries compared to Sweden. Vegetable oils that are used as food or raw material in industries could also be imported for combustion, but this is not reasonable today since the energy prices are relatively low. Restrictions allow import of SRM exclusively from Denmark. This is today the only limit for increased imports of animal based liquid fat. The restrictions for handle and combustion of animal and vegetable based liquid waste products are partly unclear since this is covered in several regulations that are not easy to interpret. The new directive for combustion of waste (2000/76/EG) is valid for animal based waste products but not for cadaver or vegetable based waste products from provisions industries. This study has shown that more than 27,400 tonnes of animal based liquid waste products and about 6,000 tonnes of vegetable based liquid waste products were used for combustion in Sweden

Perceived Thermal Discomfort and Stress Behaviours Affecting Students’ Learning in Lecture Theatres in the Humid Tropics

Directory of Open Access Journals (Sweden)

Tamaraukuro Tammy Amasuomo

2016-04-01

Full Text Available The study investigated the relationship between students’ perceived thermal discomfort and stress behaviours affecting their learning in lecture theatres in the humid tropics. Two lecture theatres, LTH-2 and 3, at the Niger Delta University, Nigeria, were used for the study. Two groups of students from the Faculties of Agriculture and Engineering and the Department of Technology Education constituted the population. The sample size selected through random sampling for Groups A and B was 210 and 370 students, respectively. Objective and self-report instruments were used for data collection. The objective instrument involved physical measurement of the two lecture theatres and of the indoor temperature, relative humidity and air movement. The self-report instrument was a questionnaire that asked for the students perceived indoor thermal discomfort levels and the effect of indoor thermal comfort level on perceived stress behaviours affecting their learning. The objective indoor environmental data indicated thermal discomfort with an average temperature of 29–32 °C and relative humidity of 78% exceeding the ASHARE [1] and Olgyay [2].The students’ experienced a considerable level of thermal discomfort and also perceived that stress behaviours due to thermal discomfort affected their learning. Further, there were no significant differences in the perceived thermal discomfort levels of the two groups of students in LTH-2 and 3. Furthermore, stress behaviours affecting learning as perceived by the two groups of students did not differ significantly. In addition, no correlation existed between the perceived indoor thermal discomfort levels and stress behaviour levels affecting learning for students in LTH-2, because the arousal level of the students in the thermal environment was likely higher than the arousal level for optimal performance [3,4]. However, a correlation existed in the case of students in LTH-3, which was expected because it only

Emergence of nutrient limitation in tropical dry forests: hypotheses from simulation models

Science.gov (United States)

Medvigy, D.; Waring, B. G.; Xu, X.; Trierweiler, A.; Werden, L. K.; Wang, G.; Zhu, Q.; Powers, J. S.

2017-12-01

It is unclear to what extent tropical dry forest productivity may be limited by nutrients. Direct assessment of nutrient limitation through fertilization experiments has been rare, and paradigms pertaining to other ecosystems may not extend to tropical dry forests. For example, because dry tropical forests have a lower water supply than moist tropical forests, dry forests can have lower decomposition rates, higher soil carbon and nitrogen concentrations, and a more open nitrogen cycle than moist forests. We used a mechanistic, numerical model to generate hypotheses about nutrient limitation in tropical dry forests. The model dynamically couples ED2 (vegetation dynamics), MEND (biogeochemistry), and N-COM (plant-microbe competition for nutrients). Here, the MEND-component of the model has been extended to include nitrogen (N) and phosphorus (P) cycles. We focus on simulation of sixteen 25m x 25m plots in Costa Rica where a fertilization experiment has been underway since 2015. Baseline simulations are characterized by both nitrogen and phosphorus limitation of vegetation. Fertilization with N and P increased vegetation biomass, with N fertilization having a somewhat stronger effect. Nutrient limitation was also sensitive to climate and was more pronounced during drought periods. Overflow respiration was identified as a key process that mitigated nutrient limitation. These results suggest that, despite often having richer soils than tropical moist forests, tropical dry forests can also become nutrient-limited. If the climate becomes drier in the next century, as is expected for Central America, drier soils may decrease microbial activity and exacerbate nutrient limitation. The importance of overflow respiration underscores the need for appropriate treatment of microbial dynamics in ecosystem models. Ongoing and new nutrient fertilization experiments will present opportunities for testing whether, and how, nutrient limitation may indeed be emerging in tropical dry

Scaling estimates of vegetation structure in Amazonian tropical forests using multi-angle MODIS observations

Science.gov (United States)

de Moura, Yhasmin Mendes; Hilker, Thomas; Goncalves, Fabio Guimarães; Galvão, Lênio Soares; dos Santos, João Roberto; Lyapustin, Alexei; Maeda, Eduardo Eiji; de Jesus Silva, Camila Valéria

2018-01-01

Detailed knowledge of vegetation structure is required for accurate modelling of terrestrial ecosystems, but direct measurements of the three dimensional distribution of canopy elements, for instance from LiDAR, are not widely available. We investigate the potential for modelling vegetation roughness, a key parameter for climatological models, from directional scattering of visible and near-infrared (NIR) reflectance acquired from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS). We compare our estimates across different tropical forest types to independent measures obtained from: (1) airborne laser scanning (ALS), (2) spaceborne Geoscience Laser Altimeter System (GLAS)/ICESat, and (3) the spaceborne SeaWinds/QSCAT. Our results showed linear correlation between MODIS-derived anisotropy to ALS-derived entropy (r2= 0.54, RMSE=0.11), even in high biomass regions. Significant relationships were also obtained between MODIS-derived anisotropy and GLAS-derived entropy (0.52≤ r2≤ 0.61; pMODIS-derived anisotropy and backscattering measurements (σ0) from SeaWinds/QuikSCAT presented an r2 of 0.59 and a RMSE of 0.11. We conclude that multi-angular MODIS observations are suitable to extrapolate measures of canopy entropy across different forest types, providing additional estimates of vegetation structure in the Amazon. PMID:29618964

Drivers of Global Vegetation Biomass Trends between 1988 and 2008

KAUST Repository

McCabe, Matthew; Liu, Yi; Evans, Jason; De Jeu, Richard; van Dijk, Albert

2013-01-01

Vegetation optical depth (VOD) is an indicator of the vegetation water content of both woody and leaf components in terrestrial biomass as derived from passive microwave observations. VOD is distinctly different from products derived from optical remote sensing: it is less prone to saturation in dense canopy; is sensitive to both photosynthetic and non-photosynthetic biomass; is less affected by atmospheric conditions; and is of coarser spatial resolution. Here, VOD retrievals from a series of sensors are blended to produce a time series from 1988 through to 2008, and a global analysis is undertaken to quantify and attribute global VOD trends over the same period. We conduct Mann-Kendall linear trend tests on annual average VOD to identify regions of significant change. Patterns for these regions were evaluated against independent datasets to diagnose the underlying cause of the observed trends. Results indicate that: (1) over grassland and shrubland, VOD patterns correspond strongly to temporal precipitation patterns; (2) over croplands, annual average VOD shows a general increase that corresponds to reported crop yield patterns and can be attributed to a combination of precipitation patterns and agricultural improvement; (3) over humid tropical forest, the spatial pattern of VOD decline agrees well with deforestation patterns identified in previous studies; and (4) over boreal forests, regional VOD declines can be attributed to a combination of fires and logging. We conclude that VOD can be used to estimate and interpret global changes in total above ground vegetation biomass. We expect that this new observationally based remote sensing data source will be of considerable interest to hydrological, agricultural, climate change and carbon cycle studies, and provide new insights into these and related process investigations.

Drivers of Global Vegetation Biomass Trends between 1988 and 2008

KAUST Repository

McCabe, Matthew

2013-12-01

Vegetation optical depth (VOD) is an indicator of the vegetation water content of both woody and leaf components in terrestrial biomass as derived from passive microwave observations. VOD is distinctly different from products derived from optical remote sensing: it is less prone to saturation in dense canopy; is sensitive to both photosynthetic and non-photosynthetic biomass; is less affected by atmospheric conditions; and is of coarser spatial resolution. Here, VOD retrievals from a series of sensors are blended to produce a time series from 1988 through to 2008, and a global analysis is undertaken to quantify and attribute global VOD trends over the same period. We conduct Mann-Kendall linear trend tests on annual average VOD to identify regions of significant change. Patterns for these regions were evaluated against independent datasets to diagnose the underlying cause of the observed trends. Results indicate that: (1) over grassland and shrubland, VOD patterns correspond strongly to temporal precipitation patterns; (2) over croplands, annual average VOD shows a general increase that corresponds to reported crop yield patterns and can be attributed to a combination of precipitation patterns and agricultural improvement; (3) over humid tropical forest, the spatial pattern of VOD decline agrees well with deforestation patterns identified in previous studies; and (4) over boreal forests, regional VOD declines can be attributed to a combination of fires and logging. We conclude that VOD can be used to estimate and interpret global changes in total above ground vegetation biomass. We expect that this new observationally based remote sensing data source will be of considerable interest to hydrological, agricultural, climate change and carbon cycle studies, and provide new insights into these and related process investigations.

Heating, Ventilation, and Air Conditioning Design Strategy for a Hot-Humid Production Builder

Energy Technology Data Exchange (ETDEWEB)

Kerrigan, P. [Building Science Corporation, Somerville, MA (United States)

2014-03-01

Building Science Corporation (BSC) worked directly with the David Weekley Homes - Houston division to develop a cost-effective design for moving the HVAC system into conditioned space. In addition, BSC conducted energy analysis to calculate the most economical strategy for increasing the energy performance of future production houses in preparation for the upcoming code changes in 2015. This research project addressed the following questions: 1. What is the most cost effective, best performing and most easily replicable method of locating ducts inside conditioned space for a hot-humid production home builder that constructs one and two story single family detached residences? 2. What is a cost effective and practical method of achieving 50% source energy savings vs. the 2006 International Energy Conservation Code for a hot-humid production builder? 3. How accurate are the pre-construction whole house cost estimates compared to confirmed post construction actual cost?

Use of Plastic Mulch for Vegetable Production

OpenAIRE

Maughan, Tiffany; Drost, Dan

2016-01-01

Plastic mulches are used commercially for both vegetables and small fruit crops. Vegetable crops well suited for production with plastic mulch are typically high value row crops. This fact sheet describes the advantages, disadvantages, installation, and planting considerations. It includes sources for plastic and equipment.

STOVE: Seed treatments for organic vegetable production

NARCIS (Netherlands)

Schmitt, A.; Jahn, M.; Kromphardt, C.; Krauthausen, H.J.; Roberts, S.J.; Wright, S.A.I.; Amein, T.; Forsberg, G.; Tinivella, F.; Gullino, M.L.; Wikström, M.; Wolf, van der J.M.; Groot, S.P.C.; Werner, S.; Koch, E.

2008-01-01

The aim of the EU-financed research project „STOVE“ (Seed Treatments for Organic Vegetable Production) is to evaluate different methods potentially suited for seed treatment of vegetables in organic farming regarding their efficacy, to optimise these methods, and where feasible to combine them with

Glacial/Interglacial climate and vegetation history of North-East of Brazil during the last 1.5 Ma and their connection to the Amazonian rainforest

Science.gov (United States)

Kern, A.; Baker, P. A.; Cruz, F. W., Sr.; Dwyer, G. S.; Silva, C. G.; Oliveira, A. S.; Willard, D. A.

2016-12-01

Northeastern (NE) Brazil is characterized today by a dry climate and vegetation, which separate the humid forests of the Amazonia from those along the Atlantic coast. Species composition and molecular genetics suggest phases of exchange between these forests in the past and the NE region is the most likely corridor for migration. However, the vegetation history of the NE is largely unknown, leaving questions on the impact of glacial stages on the forest composition and the timing of cyclic transitions from tropical rainforest to semi-arid vegetation or vice versa. Here, we present preliminary results from a marine record recovered from the equatorial Brazilian continental margin covering the last 1.5 Ma. Pollen-based reconstructions across several glacial and interglacial stages provide data on vegetation expansion and retraction of these different biomes. Vegetation changes during drying/cooling events in the NE, which may be linked to movements of the Inter Tropical Convergence Zone or/and intensities of the South American Monsoon System. Increases in terrestrial input to the core site during these climatic events may be of NE origin or Amazon origin. In the latter case, these increases would mark a decrease or reversal of the strength of the North Brazil Current. This study is funded by FAPESP projects 2015/18314-7, 2014/05582-0 and the FAPESPBIOTA/NSF-Dimensions project 2012/50260-6).

Oxygen Isotope Composition of Phytoliths From Australian Tropical Forests: Towards a New Paleoclimate Tool for the Tropical Pacific area

Science.gov (United States)

Alexandre, A.; Crespin, J.; Sonzogni, C.; Sylvestre, F.; Hilbert, D.

2008-12-01

Obtaining new continental δ18Ophytolith records from the tropical pacific area would help to further investigate 1) synchronicity between vegetation and climate changes, and 2) climate interactions between ocean and continent through comparison with oceanic reference δ18O records. In this aim, we produce a calibration of the thermo-dependant relationship between δ18Ophytolith and δ18Orainfall for present phytolith assemblages from Queensland rainforests (Australia). Phytoliths were extracted from soil humic horizons sampled along several elevation, temperature and rainfall gradients. Phytolith samples of 1.6mg were analyzed using a newly calibrated IR-laser fluorination technique, performed after a controlled isotopic exchanged procedure. The long term reproducibility on δ18O measurements is sap should equal to δ18Osoil water. Moreover, because relative humidity is close to 100%, soil evaporation is weak and δ18Osoil water is assumed to be similar to δ18Orainfall. The obtained thermo-dependant relationship between δ18Ophytolith and δ18O mean monthly rainfall of the wet season (r=0.68) is close to the equilibrium fractionation equations obtained for quartz and diatoms. Effects of forest fires on phytoliths dehydration and δ18Ophytolith are tested through heating experiments. Provided that phytolith assemblages present a morphological tropical forest pattern, δ18Ophytolith records from sediments can now be interpreted in term of δ18Osoil water, or δ18Orainfall (provided that no soil evaporation is assumed), and temperature changes. This is a first step in further investigating synchronicity between vegetation changes, global climate changes and ENSO activity in the West-Pacific area.

Numerical Modelling Of Humid Air Flow Around A Porous Body

Directory of Open Access Journals (Sweden)

Bohojło-Wiśniewska Aneta

2015-09-01

Full Text Available This paper presents an example of humid air flow around a single head of Chinese cabbage under conditions of complex heat transfer. This kind of numerical simulation allows us to create a heat and humidity transfer model between the Chinese cabbage and the flowing humid air. The calculations utilize the heat transfer model in porous medium, which includes the temperature difference between the solid (vegetable tissue and fluid (air phases of the porous medium. Modelling and calculations were performed in ANSYS Fluent 14.5 software.

Large-scale carbon stock assessment of woody vegetation in tropical dry deciduous forest of Sathanur reserve forest, Eastern Ghats, India.

Science.gov (United States)

Gandhi, Durai Sanjay; Sundarapandian, Somaiah

2017-04-01

Tropical dry forests are one of the most widely distributed ecosystems in tropics, which remain neglected in research, especially in the Eastern Ghats. Therefore, the present study was aimed to quantify the carbon storage in woody vegetation (trees and lianas) on large scale (30, 1 ha plots) in the dry deciduous forest of Sathanur reserve forest of Eastern Ghats. Biomass of adult (≥10 cm DBH) trees was estimated by species-specific allometric equations using diameter and wood density of species whereas in juvenile tree population and lianas, their respective general allometric equations were used to estimate the biomass. The fractional value 0.4453 was used to convert dry biomass into carbon in woody vegetation of tropical dry forest. The mean aboveground biomass value of juvenile tree population was 1.86 Mg/ha. The aboveground biomass of adult trees ranged from 64.81 to 624.96 Mg/ha with a mean of 245.90 Mg/ha. The mean aboveground biomass value of lianas was 7.98 Mg/ha. The total biomass of woody vegetation (adult trees + juvenile population of trees + lianas) ranged from 85.02 to 723.46 Mg/ha, with a mean value of 295.04 Mg/ha. Total carbon accumulated in woody vegetation in tropical dry deciduous forest ranged from 37.86 to 322.16 Mg/ha with a mean value of 131.38 Mg/ha. Adult trees accumulated 94.81% of woody biomass carbon followed by lianas (3.99%) and juvenile population of trees (1.20%). Albizia amara has the greatest biomass and carbon stock (58.31%) among trees except for two plots (24 and 25) where Chloroxylon swietenia contributed more to biomass and carbon stock. Similarly, Albizia amara (52.4%) showed greater carbon storage in juvenile population of trees followed by Chloroxylon swietenia (21.9%). Pterolobium hexapetalum (38.86%) showed a greater accumulation of carbon in liana species followed by Combretum albidum (33.04%). Even though, all the study plots are located within 10 km radius, they show a significant spatial variation among

Implications of incorporating N cycling and N limitations on primary production in an individual-based dynamic vegetation model

Science.gov (United States)

Smith, B.; Wårlind, D.; Arneth, A.; Hickler, T.; Leadley, P.; Siltberg, J.; Zaehle, S.

2014-04-01

The LPJ-GUESS dynamic vegetation model uniquely combines an individual- and patch-based representation of vegetation dynamics with ecosystem biogeochemical cycling from regional to global scales. We present an updated version that includes plant and soil N dynamics, analysing the implications of accounting for C-N interactions on predictions and performance of the model. Stand structural dynamics and allometric scaling of tree growth suggested by global databases of forest stand structure and development were well reproduced by the model in comparison to an earlier multi-model study. Accounting for N cycle dynamics improved the goodness of fit for broadleaved forests. N limitation associated with low N-mineralisation rates reduces productivity of cold-climate and dry-climate ecosystems relative to mesic temperate and tropical ecosystems. In a model experiment emulating free-air CO2 enrichment (FACE) treatment for forests globally, N limitation associated with low N-mineralisation rates of colder soils reduces CO2 enhancement of net primary production (NPP) for boreal forests, while some temperate and tropical forests exhibit increased NPP enhancement. Under a business-as-usual future climate and emissions scenario, ecosystem C storage globally was projected to increase by ca. 10%; additional N requirements to match this increasing ecosystem C were within the high N supply limit estimated on stoichiometric grounds in an earlier study. Our results highlight the importance of accounting for C-N interactions in studies of global terrestrial N cycling, and as a basis for understanding mechanisms on local scales and in different regional contexts.

The importance of vegetation change in the prediction of future tropical cyclone flood statistics

Science.gov (United States)

Irish, J. L.; Resio, D.; Bilskie, M. V.; Hagen, S. C.; Weiss, R.

2015-12-01

Global sea level rise is a near certainty over the next century (e.g., Stocker et al. 2013 [IPCC] and references therein). With sea level rise, coastal topography and land cover (hereafter "landscape") is expected to change and tropical cyclone flood hazard is expected to accelerate (e.g., Irish et al. 2010 [Ocean Eng], Woodruff et al. 2013 [Nature], Bilskie et al. 2014 [Geophys Res Lett], Ferreira et al. 2014 [Coast Eng], Passeri et al. 2015 [Nat Hazards]). Yet, the relative importance of sea-level rise induced landscape change on future tropical cyclone flood hazard assessment is not known. In this paper, idealized scenarios are used to evaluate the relative impact of one class of landscape change on future tropical cyclone extreme-value statistics in back-barrier regions: sea level rise induced vegetation migration and loss. The joint probability method with optimal sampling (JPM-OS) (Resio et al. 2009 [Nat Hazards]) with idealized surge response functions (e.g., Irish et al. 2009 [Nat Hazards]) is used to quantify the present-day and future flood hazard under various sea level rise scenarios. Results are evaluated in terms of their impact on the flood statistics (a) when projected flood elevations are included directly in the JPM analysis (Figure 1) and (b) when represented as additional uncertainty within the JPM integral (Resio et al. 2013 [Nat Hazards]), i.e., as random error. Findings are expected to aid in determining the level of effort required to reasonably account for future landscape change in hazard assessments, namely in determining when such processes are sufficiently captured by added uncertainty and when sea level rise induced vegetation changes must be considered dynamically, via detailed modeling initiatives. Acknowledgements: This material is based upon work supported by the National Science Foundation under Grant No. CMMI-1206271 and by the National Sea Grant College Program of the U.S. Department of Commerce's National Oceanic and

Emerging new poleroviruses and tospoviruses affecting vegetables in Asia and breeding for resistance

OpenAIRE

Relevante, C.; Cheewachaiwit, S.; Chuapong, J.; Stratongjun, M.; Salutan, V.E.; Peters, D.; Balatero, C.H.; Hoop, de, S.J.

2012-01-01

The diseases caused by aphid-borne poleroviruses (genus Polerovirus, family Luteoviridae) and thrips-borne tospoviruses (genus Tospovirus, family Bunyaviridae) are emerging threats to the production of economically important vegetable and fruit crops in tropical and sub-tropical Asia. To date, at least 13 different polerovirus species have been characterized. In Asia, the reported poleroviruses include Cucurbit aphid-borne yellows virus (CABYV), Melon aphid-borne yellows virus (MABYV) and Sua...

Groundwater circulations within a tropical humid andesitic volcanic watershed using the temperature as a tracer

Science.gov (United States)

Selles, Adrien; Violette, Sophie; Hendrayana, Heru

2014-05-01

Groundwater flow within volcano-detritic environment, is of prime importance to many human needs and activities, from the supply of clean drinking water to the extraction of hydrocarbons or geothermal energy. However, the heterogeneity of the geological formations makes difficult to quantify the groundwater spatial distribution. Moreover, its temporal variation in tropical humid regions is sometimes poorly known. For instance, the surronding of the Merapi volcano, in Central Java, Indonesia, is an area of high but seasonal rainfall, and extensive crop irrigation. It has a large population and a need to increase food and potable water supplies depending upon exploiting groundwater ressources. The stress on these resources increases with the intensification of the demography, the agricultural practices and the industrial exploitations. In order to implement a sustainable management of the water resources, the description of the groundwater circulations and the quantification of the resources is needed. A mutidisciplinary approach has been performed at the watershed scale, including geology, hydrogeochemistry and long term hydrogeological monitoring. The data synthesis and constisency have been confirm with a numerical model of physical processes. Based on a geological and geomorphological study, the hydrogeological watershed on the Eastern flank of the Merapi volcano is composed by an alternation of aquitards (mainly ashes, tuffs and clay) and aquifers (sand, gravel and boulders). The deep aquifers are agenced in conduit following the burried channel of the paleo-rivers. The eastern flank of Merapi provides excellent example of a volcanic-sedimentary environment. From 20 cold springs of 3 spring zones, sampled on 2 hydrological years (2011 to 2013), the study of the transfer into the saturated zone from upstream to downstream, given the geological context and topography, allows to estimate the role of supply from high and low altitudes to the recharge processes. The

Measuring Convective Mass Fluxes Over Tropical Oceans

Science.gov (United States)

Raymond, David

2017-04-01

Deep convection forms the upward branches of all large-scale circulations in the tropics. Understanding what controls the form and intensity of vertical convective mass fluxes is thus key to understanding tropical weather and climate. These mass fluxes and the corresponding conditions supporting them have been measured by recent field programs (TPARC/TCS08, PREDICT, HS3) in tropical disturbances considered to be possible tropical storm precursors. In reality, this encompasses most strong convection in the tropics. The measurements were made with arrays of dropsondes deployed from high altitude. In some cases Doppler radar provided additional measurements. The results are in some ways surprising. Three factors were found to control the mass flux profiles, the strength of total surface heat fluxes, the column-integrated relative humidity, and the low to mid-tropospheric moist convective instability. The first two act as expected, with larger heat fluxes and higher humidity producing more precipitation and stronger lower tropospheric mass fluxes. However, unexpectedly, smaller (but still positive) convective instability produces more precipitation as well as more bottom-heavy convective mass flux profiles. Furthermore, the column humidity and the convective instability are anti-correlated, at least in the presence of strong convection. On spatial scales of a few hundred kilometers, the virtual temperature structure appears to be in dynamic balance with the pattern of potential vorticity. Since potential vorticity typically evolves on longer time scales than convection, the potential vorticity pattern plus the surface heat fluxes then become the immediate controlling factors for average convective properties. All measurements so far have taken place in regions with relatively flat sea surface temperature (SST) distributions. We are currently seeking funding for a measurement program in the tropical east Pacific, a region that exhibits strong SST gradients and

Landscape-scale tropical forest dynamics: Relating canopy traits and topographically derived hydrologic indices in a floodplain system using CAO-AToMS

Science.gov (United States)

Chadwick, K.; Asner, G. P.

2012-12-01

The geomorphology of floodplains in the humid tropics has been used to infer basic classifications of forest types. However, analysis of the landscape-scale topographic and hydrologic patterns underpinning spatial variation in forest composition and function remain elusive due to the sparse coverage of forest plots, coarse resolution remotely sensed data, and the challenges of collecting first order hydrologic data. Airborne remote measurements provide an opportunity to consider the relationship between high-resolution topographic and derived hydrologic environmental gradients, and forest canopy characteristics with important cascading effects on ecosystem function and biosphere-atmosphere interactions. In 2011, the Carnegie Airborne Observatory (CAO) Airborne Taxonomic Mapping System (AToMS) was used to map a large section of the Los Amigos Conservation Concession harboring largely intact lowland humid tropical forest in the southwestern Peruvian Amazon. The CAO Visible-Shortwave Imaging Spectrometer (VSWIR) collected 480-band high-fidelity imaging spectroscopy data of the forest canopy, while its high-resolution dual waveform LiDAR captured information on canopy structure and the underlying terrain. The data were used to quantify relationships between topographic and hydrologic gradients and forest functional traits. Results suggest strong local hydrogeomorphic control over vegetation spectral properties with known relationships to canopy functional traits, including pigment and nutrient concentrations and light capture, as well as canopy structural characteristics, including vegetation height, understory plant cover, and aboveground biomass. Data from CAO-AToMS reveals local-scale patterns in environmental conditions and ecological variation that meets or exceeds the variation previously reported across ecosystems of the Western Amazon Basin.

Landslides Zonation Hazard: relation between geological structures and landslides occurrence in hilly tropical regions of Brazil

Directory of Open Access Journals (Sweden)

RODRIGO I. CERRI

2017-08-01

Full Text Available ABSTRACT This paper presents a new approach of landslides zonation hazard studies, based on an integrated study of structural data along with geomorphological and external factors, in a hilly regions of Brazil, covered by a tropical humid rain-forest, called Serra do Mar. The Serra do Mar consists of a hilly region along the east coast of Brazil, with high slopes and many geological structures in a gneiss - migmatitic terrain. In contrast to traditional approaches, this method proposes that structural data (foliation, fractures and bedding planes and its relation with the slope geometry, is important to be consider in the landslide zonation hazard, along with declivity, relative relief, soil and rock properties, land use and vegetation cover and hydrogeological and climate factors. Results show that slopes with high hazard have the same dip direction of geological structures. Landslide zonation hazard using structural data contributes to a better understanding of how these structures, preserved in tropical residual soils, influence on slope stability and generates landslides.

Landslides Zonation Hazard: relation between geological structures and landslides occurrence in hilly tropical regions of Brazil.

Science.gov (United States)

Cerri, Rodrigo I; Reis, Fábio A G V; Gramani, Marcelo F; Giordano, Lucilia C; Zaine, José Eduardo

2017-01-01

This paper presents a new approach of landslides zonation hazard studies, based on an integrated study of structural data along with geomorphological and external factors, in a hilly regions of Brazil, covered by a tropical humid rain-forest, called Serra do Mar. The Serra do Mar consists of a hilly region along the east coast of Brazil, with high slopes and many geological structures in a gneiss - migmatitic terrain. In contrast to traditional approaches, this method proposes that structural data (foliation, fractures and bedding planes) and its relation with the slope geometry, is important to be consider in the landslide zonation hazard, along with declivity, relative relief, soil and rock properties, land use and vegetation cover and hydrogeological and climate factors. Results show that slopes with high hazard have the same dip direction of geological structures. Landslide zonation hazard using structural data contributes to a better understanding of how these structures, preserved in tropical residual soils, influence on slope stability and generates landslides.

Human population growth offsets climate-driven increase in woody vegetation in sub-Saharan Africa.

Science.gov (United States)

Brandt, Martin; Rasmussen, Kjeld; Peñuelas, Josep; Tian, Feng; Schurgers, Guy; Verger, Aleixandre; Mertz, Ole; Palmer, John R B; Fensholt, Rasmus

2017-03-06

The rapidly growing human population in sub-Saharan Africa generates increasing demand for agricultural land and forest products, which presumably leads to deforestation. Conversely, a greening of African drylands has been reported, but this has been difficult to associate with changes in woody vegetation. There is thus an incomplete understanding of how woody vegetation responds to socio-economic and environmental change. Here we used a passive microwave Earth observation data set to document two different trends in land area with woody cover for 1992-2011: 36% of the land area (6,870,000 km 2 ) had an increase in woody cover largely in drylands, and 11% had a decrease (2,150,000 km 2 ), mostly in humid zones. Increases in woody cover were associated with low population growth, and were driven by increases in CO 2 in the humid zones and by increases in precipitation in drylands, whereas decreases in woody cover were associated with high population growth. The spatially distinct pattern of these opposing trends reflects, first, the natural response of vegetation to precipitation and atmospheric CO 2 , and second, deforestation in humid areas, minor in size but important for ecosystem services, such as biodiversity and carbon stocks. This nuanced picture of changes in woody cover challenges widely held views of a general and ongoing reduction of the woody vegetation in Africa.

Fire regimes and vegetation change in tropical northern Australia during the late-Holocene

Science.gov (United States)

Mackenzie, Lydia; Moss, Patrick; Ulm, Sean; Sloss, Craig; Heijnis, Henk; Jacobsen, Geraldine

2016-04-01

This study explores the impact of human occupation and abandonment on fire regimes and vegetation communities in the South Wellesley Islands, Gulf of Carpentaria, tropical northern Australia, using charcoal and pollen analysis from four sediment records. Pollen analysis from wetland sediments reveal vegetation succession from mangrove communities to hypersaline mudflats and open woodlands occurred during the late-Holocene. Aquatic species replaced salt tolerant species as the prograding shoreline and dune development formed the Marralda wetlands by 800 cal a BP on the south east coast of Bentinck Island. Wetlands developed on the north and west coast by 500 and 450 cal a BP, respectively. The timing of wetland initiation indicates localised late-Holocene sea level regression, stabilisation and coastal plain development in the Gulf of Carpentaria. Wetland initiation encouraged permanent human occupation of the South Wellesley archipelago, with ongoing archaeological research finding permanent occupation in the last 1500 years, followed by a significant increase in sites from 700 years ago, which peaks over the last 300 years. Macro-charcoal (>125μm) accumulation rates provide a record of fire intensity and frequency across the Island. Both local and regional fire events increase in the last 700 years as traditional owners occupied the Island, with local fires occurring every 104 and 74 years on average (N= 4 and 5 respectively). In the 1950's traditional Indigenous Kaiadilt fire management practices ceased, with the frequency and peak magnitude of fire events significantly increasing and vegetation communities becoming more open. The South Wellesley Islands were unoccupied until the 1980's and were not influenced by European occupation. This study of an Island ecosystem during the late-Holocene provides insight into the effect of human presence and fire regimes on vegetation composition and distribution in a fire resilient environment.

Disturbance Hydrology in the Tropics: The Galápagos Islands as a Case Study

Science.gov (United States)

Riveros-Iregui, D. A.; Schmitt, S.; Percy, M.; Hu, J.; Singha, K.; Mirus, B. B.

2015-12-01

Tropical Latin America has shown the largest acceleration in land use change in recent decades. It is well established that changes in vegetation cover can lead to changes in water demand, evapotranspiration, and eventually soil textural characteristics. Given the projected changes in the intensity and distribution of rainfall in tropical regions in the coming decades, it is critical to characterize how changes in land use change across different climatic zones may fundamentally reshape water availability and storage, soil composition and associated hydraulic properties, and overall watershed hydrologic behavior. This study evaluates the role of anthropogenic disturbance on hydrological processes across different climatic zones in the tropics. We focus specifically on San Cristobal Island, the second most populated island of the iconic Galapagos archipelago, which is currently undergoing severe anthropogenic transformation. The island contains a spectrum of climates, ranging from very humid to arid, and has seen a dramatic increase in tourism and an increase in the permanent population of greater than 1000% in the last 40 years. Over 70% of the landscape of San Cristobal has been altered by land use change and invasive species. Our study identifies the complex interactions among hydrological, geological, economic, and social variables that tropical island systems will face in the years ahead, and the role and effects of a dynamic hydrologic cycle across multiple scales.

Unprecedented drought over tropical South America in 2016: significantly under-predicted by tropical SST.

Science.gov (United States)

Erfanian, Amir; Wang, Guiling; Fomenko, Lori

2017-07-19

Tropical and sub-tropical South America are highly susceptible to extreme droughts. Recent events include two droughts (2005 and 2010) exceeding the 100-year return value in the Amazon and recurrent extreme droughts in the Nordeste region, with profound eco-hydrological and socioeconomic impacts. In 2015-2016, both regions were hit by another drought. Here, we show that the severity of the 2015-2016 drought ("2016 drought" hereafter) is unprecedented based on multiple precipitation products (since 1900), satellite-derived data on terrestrial water storage (since 2002) and two vegetation indices (since 2004). The ecohydrological consequences from the 2016 drought are more severe and extensive than the 2005 and 2010 droughts. Empirical relationships between rainfall and sea surface temperatures (SSTs) over the tropical Pacific and Atlantic are used to assess the role of tropical oceanic variability in the observed precipitation anomalies. Our results indicate that warmer-than-usual SSTs in the Tropical Pacific (including El Niño events) and Atlantic were the main drivers of extreme droughts in South America, but are unable to explain the severity of the 2016 observed rainfall deficits for a substantial portion of the Amazonia and Nordeste regions. This strongly suggests potential contribution of non-oceanic factors (e.g., land cover change and CO2-induced warming) to the 2016 drought.

The MODIS Vegetation Canopy Water Content product

Science.gov (United States)

Ustin, S. L.; Riano, D.; Trombetti, M.

2008-12-01

Vegetation water stress drives wildfire behavior and risk, having important implications for biogeochemical cycling in natural ecosystems, agriculture, and forestry. Water stress limits plant transpiration and carbon gain. The regulation of photosynthesis creates close linkages between the carbon, water, and energy cycles and through metabolism to the nitrogen cycle. We generated systematic weekly CWC estimated for the USA from 2000-2006. MODIS measures the sunlit reflectance of the vegetation in the visible, near-infrared, and shortwave infrared. Radiative transfer models, such as PROSPECT-SAILH, determine how sunlight interacts with plant and soil materials. These models can be applied over a range of scales and ecosystem types. Artificial Neural Networks (ANN) were used to optimize the inversion of these models to determine vegetation water content. We carried out multi-scale validation of the product using field data, airborne and satellite cross-calibration. An Algorithm Theoretical Basis Document (ATBD) of the product is under evaluation by NASA. The CWC product inputs are 1) The MODIS Terra/Aqua surface reflectance product (MOD09A1/MYD09A1) 2) The MODIS land cover map product (MOD12Q1) reclassified to grassland, shrub-land and forest canopies; 3) An ANN trained with PROSPECT-SAILH; 4) A calibration file for each land cover type. The output is an ENVI file with the CWC values. The code is written in Matlab environment and is being adapted to read not only the 8 day MODIS composites, but also daily surface reflectance data. We plan to incorporate the cloud and snow mask and generate as output a geotiff file. Vegetation water content estimates will help predicting linkages between biogeochemical cycles, which will enable further understanding of feedbacks to atmospheric concentrations of greenhouse gases. It will also serve to estimate primary productivity of the biosphere; monitor/assess natural vegetation health related to drought, pollution or diseases

Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam

Directory of Open Access Journals (Sweden)

Pham Quang Thai

2015-12-01

Conclusions: Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the seasonality of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of AH on disease transmission may be different in cold-dry versus hot-humid settings.

Breed-Specific Haematologic Reference Values in Adult Turkeys (Meleagris gallopavo in the Humid Tropics of Nigeria

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Daniel-Igwe G.

2017-03-01

Full Text Available One hundred (50 males and 50 females B-not strain indigenous turkeys, Meleagris gallopavo, were used to determine the reference values for their haematological parameters. The turkeys were housed in the poultry unit and jugular venepunctures were used to collect their blood. The haematological parameters were determined using standard procedures. The mean values of: the packed cell volume (PCV; 37.29 ± 0.37 %, red blood cell (RBC counts (2.50 ± 0.44 × 106.µl−1, haemoglobin concentration (Hbc; 10.89 ± 0.34 g.dl−1, mean corpuscular volume (MCV; 150.63 ± 0.73 fl, mean corpuscular haemoglobin (MCH; 44.29 ± 1.78 pg, mean corpuscular haemoglobin concentration (MCHC; 29.10 ± 0.73 g.dl−1, and white blood cell (WBC counts (12.41 ± 0.83 × 103 µl−1 were determined. No significant differences were found between the male and female B-not strain turkeys in this study. The results will help in the interpretation of cases of disease when there are variations in the values and serve as baseline data for B-not strain of turkeys in the humid tropics.

Flood moderation by large reservoirs in the humid tropics of Western ghat region of Kerala, India

Energy Technology Data Exchange (ETDEWEB)

Abe, George [Centre for Water Resources Development and Management, Sub Centre, Kottayam South P.O, Kottayam-686 039, Kerala (India); James, E.J. [Water Institute and Dean (Research), Karunya University, Coimbatore-641 114, Tamil Nadu (India)

2013-07-01

Kerala State located in the humid tropics receives an average rainfall of 2810 mm. On an average 85% of this rainfall is received during the two monsoons spread from June to November. Midland and lowland regions of several of the river basins of Kerala experience severe flood events during the monsoons. Idamalayar hydro-electric project (1987) in Periyar River basin envisages flood control apart from power generation. This paper analyzes the flood moderation by Idamalayar reservoir considering the storage regime (inflow and outflow) which is subjected to a strong inter annual variability. The role of Idamalayar reservoir in controlling the monsoon floods is analyzed using daily data (1987-2010). The results of analysis show that the flood moderation by the reservoir is 92% when water storage is less than 50%. The reduction is 87% when reservoir storage is between 50 to 90% and moderation reduces to 62% when the reservoir storage is above 90%. Non-parametric trend analysis of fifty years of hydrologic data shows a reducing trend in inflow and storage during south-west monsoon which reduced spill and subsequent flood events during north-east monsoon.

Tree height and tropical forest biomass estimation

Science.gov (United States)

M.O. Hunter; M. Keller; D. Vitoria; D.C. Morton

2013-01-01

Tropical forests account for approximately half of above-ground carbon stored in global vegetation. However, uncertainties in tropical forest carbon stocks remain high because it is costly and laborious to quantify standing carbon stocks. Carbon stocks of tropical forests are determined using allometric relations between tree stem diameter and height and biomass....

Oceanic upwelling and productivity in the eastern tropical Pacific

International Nuclear Information System (INIS)

Fiedler, P.C.; Philbrick, V.; Chavez, F.P.

1991-01-01

An oceanographic survey of the eastern tropical Pacific Ocean in August-November 1990 found a productive, nutrient-rich, moderately high-chlorophyll surface layer in two oceanic upwelling regions: the equatorial divergence, especially east of the Galapagos, and the countercurrent divergence out to 105 degree W, > 1,000 km west of the Costa Rica Dome. Although NO 3 is not depleted in upwelling regions, relationships among nutrient concentrations and temperature in 1986-1988 data from the same area show that NO 3 is the first macronutrient to be depleted in adjacent, less-productive regions. A three-dimensional, two-layer box model of NO 3 flux within and into the euphotic zone gives estimated rates of new production that are ∼29% of measured rates of 14 C phytoplankton production. Persistence of excess NO 3 in the euphotic zone exceeds 1 yr under high-nutrient, low-chlorophyll conditions off the equator where weak upwelling, or downwelling, occurs. These results indicate substantial control or limitation of NO 3 utilization and productivity in nutrient-rich oceanic regions of the eastern tropical Pacific

Hydrolyzed Vegetable Protein Containing Products Recalls

Data.gov (United States)

U.S. Department of Health & Human Services — This list includes products subject to recall in the United States since February 2010 related to hydrolyzed vegetable protein (HVP) paste and powder distributed by...

Tropical forest cover change in the 1990s and options for future monitoring.

Science.gov (United States)

Mayaux, Philippe; Holmgren, Peter; Achard, Frédéric; Eva, Hugh; Stibig, Hans-Jürgen; Branthomme, Anne

2005-02-28

Despite the importance of the world's humid tropical forests, our knowledge concerning their rates of change remains limited. Two recent programmes (FAO 2000 Forest Resources Assessment and TREES II), exploiting the global imaging capabilities of Earth observing satellites, have recently been completed to provide information on the dynamics of tropical forest cover. The results from these independent studies show a high degree of conformity and provide a good understanding of trends at the pan-tropical level. In 1990 there were some 1150 million ha of tropical rain forest with the area of the humid tropics deforested annually estimated at 5.8 million ha (approximately twice the size of Belgium). A further 2.3 million ha of humid forest is apparently degraded annually through fragmentation, logging and/or fires. In the sub-humid and dry tropics, annual deforestation of tropical moist deciduous and tropical dry forests comes to 2.2 and 0.7 million ha, respectively. Southeast Asia is the region where forests are under the highest pressure with an annual change rate of -0.8 to -0.9%. The annual area deforested in Latin America is large, but the relative rate (-0.4 to -0.5%) is lower, owing to the vast area covered by the remaining Amazonian forests. The humid forests of Africa are being converted at a similar rate to those of Latin America (-0.4 to -0.5% per year). During this period, secondary forests have also been established, through re-growth on abandoned land and forest plantations, but with different ecological, biophysical and economic characteristics compared with primary forests. These trends are significant in all regions, but the extent of new forest cover has proven difficult to establish. These results, as well as the lack of more detailed knowledge, clearly demonstrate the need to improve sound scientific evidence to support policy. The two projects provide useful guidance for future monitoring efforts in the context of multilateral environmental

Greenhouse design for vegetable production in subtropical climate in Taiwan

NARCIS (Netherlands)

Hemming, S.; Speetjens, S.L.; Wang, D.; Tsay, J.R.

2014-01-01

In Taiwan open field vegetable production is threatened by subtropical climatic disasters, such as high wind speeds and heavy rainfall, which can cause the destruction of whole crops. Next to that vegetable production is threatened by pests and diseases resulting a high need for pesticides.

Corrosion study of steels exposed over five years to the humid tropical atmosphere of Panama

Energy Technology Data Exchange (ETDEWEB)

Jaén, Juan A., E-mail: juan.jaen@up.ac.pa [Departamento de Química Física, Edificio de Laboratorios Científicos-VIP (Panama); Iglesias, Josefina [Laboratorio de Análisis Industriales y Ciencias Ambientales (Panama)

2017-11-15

The results of assessing five-year corrosion of low-carbon and conventional weathering steels exposed to the Panamanian tropical atmosphere is presented. Two different test sites, one in Panama City: 5 km from the shoreline of the Pacific Ocean, and another in the marine environment of Fort Sherman, Caribbean coast of Panama; namely, Fort Sherman Coastal site: 100 m from coastline. The corrosion products, formed in the skyward and earthward faces in the studied tropical environment, were mainly identified using room temperature and low temperature (15 K) Mössbauer spectroscopy, and ATR-FTIR. In all samples, lepidocrocite (γ-FeOOH) and goethite (α-FeOOH) were the main constituents. Some maghemite (γ-Fe{sub 2}O{sub 3}), was also identified in Tocumen by Mössbauer spectroscopy and traces of feroxyhyte (δ-FeOOH) using ATR-FTIR. The corrosion rate values obtained are discussed in light of the atmospheric exposure conditions and atmospheric pollutants.

Impact of small variations in temperature and humidity on the reproductive activity and survival of Aedes aegypti (Diptera, Culicidae)

International Nuclear Information System (INIS)

Costa, Ethiene Arruda Pedrosa de Almeida; Santos, Eloina Maria de Mendonca; Correia, Juliana Cavalcanti; Albuquerque, Cleide Maria Ribeiro de

2010-01-01

In short space of time increase in temperature and rainfall can affect vector populations and, consequently, the diseases for them transmitted. The present study analyzed the effect of small temperature and humidity variations on the fecundity, fertility and survival of Aedes aegypti. These parameters were analyzed using individual females at temperatures ranging from 23 to 27 deg C (mean 25 deg C); 28 to 32 deg C (mean 30 deg C) and 33 to 37 deg C (mean 35 deg C) associated to 60 +- 8% and 80 +- 6% relative humidity. Females responded to an increase in temperature by reducing egg production, oviposition time and changing oviposition patterns. At 25 deg C and 80% relative humidity, females survived two-fold more and produced 40% more eggs when compared to those kept at 35 deg C and 80% relative humidity. However, in 45% of females kept at 35 deg C and 60% relative humidity oviposition was inhibited and only 15% females laid more than 100 eggs, suggesting that the intensity of the temperature effect was influenced by humidity. Gradual reductions in egg fertility at 60% relative humidity were observed with the increase in temperature, although such effect was not found in the 80% relative humidity at 25 deg C and 30 deg C. These results suggest that the reduction in population densities recorded in tropical areas during seasons when temperatures reach over 35 deg C is likely to be strongly influenced by temperature and humidity, with a negative effect on several aspects of mosquito biology. (author)

CONTROLLING FACTORS OF POTENTIAL EVAPOTRANSPIRATION ABOVE GRASSLAND IN HUMID AND ARID AREA

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. Yanto

2013-05-01

Full Text Available Potential evapotranspiration (PET is an importance process in water balance studies controlled by a number of meteorological factors such as temperature, wind speed, atmospheric pressure, solar radiation, vapor pressure gradient, relative humidity and biological factors such as vegetation type, canopy height and plant density that varied in time-scale and in spatial scale. Of all those variables, determining the most controlling factors of evapotranspiration in humid and arid area is of interest of this paper. Two sites representing humid and arid area i.e. Fermi Prairie site in Illinois and Audubon Research Ranch in Arizona respectively were investigated in this study.  The flux data employed in this study was acquired from Ameriflux Netwotk. Penmann-Monteith formula is employed in to estimate evapotranspiration rate in both sites. The result shows that the PET is in dependence on the considered meteorological factor such as shortwave radiation, vapor pressure, air temperature, wind speed, net radiation and vapor pressure deficit. It is also can be inferred from the analysis that PET is also strongly controlled by vegetation factors represented as stomatal resistance. Keywords: Potential evapotranspiration, Penmann-Monteith, humid, arid.

Biomass is the main driver of changes in ecosystem process rates during tropical forest succession.

Science.gov (United States)

Lohbeck, Madelon; Poorter, Lourens; Martínez-Ramos, Miguel; Bongers, Frans

2015-05-01

Over half of the world's forests are disturbed, and the rate at which ecosystem processes recover after disturbance is important for the services these forests can provide. We analyze the drivers' underlying changes in rates of key ecosystem processes (biomass productivity, litter productivity, actual litter decomposition, and potential litter decomposition) during secondary succession after shifting cultivation in wet tropical forest of Mexico. We test the importance of three alternative drivers of ecosystem processes: vegetation biomass (vegetation quantity hypothesis), community-weighted trait mean (mass ratio hypothesis), and functional diversity (niche complementarity hypothesis) using structural equation modeling. This allows us to infer the relative importance of different mechanisms underlying ecosystem process recovery. Ecosystem process rates changed during succession, and the strongest driver was aboveground biomass for each of the processes. Productivity of aboveground stem biomass and leaf litter as well as actual litter decomposition increased with initial standing vegetation biomass, whereas potential litter decomposition decreased with standing biomass. Additionally, biomass productivity was positively affected by community-weighted mean of specific leaf area, and potential decomposition was positively affected by functional divergence, and negatively by community-weighted mean of leaf dry matter content. Our empirical results show that functional diversity and community-weighted means are of secondary importance for explaining changes in ecosystem process rates during tropical forest succession. Instead, simply, the amount of vegetation in a site is the major driver of changes, perhaps because there is a steep biomass buildup during succession that overrides more subtle effects of community functional properties on ecosystem processes. We recommend future studies in the field of biodiversity and ecosystem functioning to separate the effects of

Remote Sensing of Tropical Ecosystems: Atmospheric Correction and Cloud Masking Matter

Science.gov (United States)

Hilker, Thomas; Lyapustin, Alexei I.; Tucker, Compton J.; Sellers, Piers J.; Hall, Forrest G.; Wang, Yujie

2012-01-01

Tropical rainforests are significant contributors to the global cycles of energy, water and carbon. As a result, monitoring of the vegetation status over regions such as Amazonia has been a long standing interest of Earth scientists trying to determine the effect of climate change and anthropogenic disturbance on the tropical ecosystems and its feedback on the Earth's climate. Satellite-based remote sensing is the only practical approach for observing the vegetation dynamics of regions like the Amazon over useful spatial and temporal scales, but recent years have seen much controversy over satellite-derived vegetation states in Amazônia, with studies predicting opposite feedbacks depending on data processing technique and interpretation. Recent results suggest that some of this uncertainty could stem from a lack of quality in atmospheric correction and cloud screening. In this paper, we assess these uncertainties by comparing the current standard surface reflectance products (MYD09, MYD09GA) and derived composites (MYD09A1, MCD43A4 and MYD13A2 - Vegetation Index) from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite to results obtained from the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm. MAIAC uses a new cloud screening technique, and novel aerosol retrieval and atmospheric correction procedures which are based on time-series and spatial analyses. Our results show considerable improvements of MAIAC processed surface reflectance compared to MYD09/MYD13 with noise levels reduced by a factor of up to 10. Uncertainties in the current MODIS surface reflectance product were mainly due to residual cloud and aerosol contamination which affected the Normalized Difference Vegetation Index (NDVI): During the wet season, with cloud cover ranging between 90 percent and 99 percent, conventionally processed NDVI was significantly depressed due to undetected clouds. A smaller reduction in NDVI due to increased

Understanding the Role of Typhoons, Fire, and Climate on the Vegetation Dynamics of Tropical Dry Forests: Looking to the Past to Develop Future Management Solutions

Science.gov (United States)

2010-04-01

centennial -to millennial scale typhoon reconstructions from the western North Pacific are far more limited. Historical government documents of typhoon... Centennial scale swings from humid to drought conditions have been documented in some tropical locations (Hodell et al., 2001). By looking to the past... depressions with a maximum depth of roughly 12 meters. The lagoon hollows are bounded by sand flats and coral reefs (Fig. 2). Core VC9 was located in the

Remotely Sensed Northern Vegetation Response to Changing Climate: Growing Season and Productivity Perspective

Science.gov (United States)

Ganguly, S.; Park, Taejin; Choi, Sungho; Bi, Jian; Knyazikhin, Yuri; Myneni, Ranga

2016-01-01

Vegetation growing season and maximum photosynthetic state determine spatiotemporal variability of seasonal total gross primary productivity of vegetation. Recent warming induced impacts accelerate shifts on growing season and physiological status over Northern vegetated land. Thus, understanding and quantifying these changes are very important. Here, we first investigate how vegetation growing season and maximum photosynthesis state are evolved and how such components contribute on inter-annual variation of seasonal total gross primary productivity. Furthermore, seasonally different response of northern vegetation to changing temperature and water availability is also investigated. We utilized both long-term remotely sensed data to extract larger scale growing season metrics (growing season start, end and duration) and productivity (i.e., growing season summed vegetation index, GSSVI) for answering these questions. We find that regionally diverged growing season shift and maximum photosynthetic state contribute differently characterized productivity inter-annual variability and trend. Also seasonally different response of vegetation gives different view of spatially varying interaction between vegetation and climate. These results highlight spatially and temporally varying vegetation dynamics and are reflective of biome-specific responses of northern vegetation to changing climate.

Morphological, physico-chemical and geochemical characterization of two weathering profiles developed on limestone from the Mintom Formation in the tropical humid zone of Cameroon

Science.gov (United States)

Engon, Thierry Constant; Abane, Monique Abessolo-Angue; Zo'o Zame, Philémon; Ekomane, Emile; Bekoa, Etienne; Mvogo, Kisito; Bitom, Dieudonné

2017-07-01

The purpose of this work was to study the morphology, physico-chemistry and geochemistry of two weathering profiles developed on limestone using observations area, basic analysis, and X-ray Fluorescence. The results showed that these soils have three main sets from the bottom to the top: the alteritic set (isalteritic and alloteritic horizons), the glaebular set (exclusively on profile TCR) with a more or less hardened duricrust, and the loose set (loose clayey and humiferous horizons). The soils were acid, with moderate cation exchange capacity, low to moderate sum of bases (0.96-8.24 meq/100 g). The base saturation, organic carbon and C/N ratio (˂15) were low. The geochemical signatures of the bedrock along the whole profile are not preserved, with SiO2 (∼45.26 wt%) being the dominant oxide followed by Al2O3 (∼13.37 wt%) and Fe2O3 (∼09.36 wt%). Also, the Si/Al ratio is always higher than 1 (2.17-4.43). The other major oxides such as MgO, K2O and Na2O show negligible contents in the profiles, while CaO is well represented at the top of the isalteritic horizon reaching 14.25 wt%. Weathering indices show that CaO, MgO, Na2O, and K2O are rapidly lost during chemical weathering and the amount of these elements lost is proportional to the degree of weathering. Humid tropical soils show pedological evolution mainly dominated by the behaviour of silicon and aluminium, with an intensive release of carbonates during the early stage of weathering. However, contrary to soils in temperate climates, in which bisiallitisation is the predominant process, soils of the humid tropical zone, characterized by high evacuation of silica concomitantly to notable accumulations of aluminium, allitisation and monosiallitisation predominate.

Sustainability aspects of biobased products : comparison of different crops and products from the vegetable oil platform

NARCIS (Netherlands)

Meesters, K.P.H.; Corré, W.J.; Conijn, J.G.; Patel, M.K.; Bos, H.L.

2012-01-01

This study focusses on the production of vegetable oil based products. A limited number of aspacts of the sustainability of the full chain (from agriculture to product at the factory gate) was evaluated. Three different vegetable oils were taken into account: palm oil, soy oil and rapeseed oil. Also

7 CFR 318.13-14 - Movement of processed fruits, vegetables, and other products.

Science.gov (United States)

2010-01-01

... 7 Agriculture 5 2010-01-01 2010-01-01 false Movement of processed fruits, vegetables, and other... fruits, vegetables, and other products. (a) Fruits, vegetables, and other products that are processed.../plants/manuals/ports/downloads/puerto_rico.pdf. (b) Consignments of processed fruits, vegetables, or...

Determining the K coefficient to leaf area index estimations in a tropical dry forest

Science.gov (United States)

Magalhães, Sarah Freitas; Calvo-Rodriguez, Sofia; do Espírito Santo, Mário Marcos; Sánchez Azofeifa, Gerardo Arturo

2018-03-01

Vegetation indices are useful tools to remotely estimate several important parameters related to ecosystem functioning. However, improving and validating estimations for a wide range of vegetation types are necessary. In this study, we provide a methodology for the estimation of the leaf area index (LAI) in a tropical dry forest (TDF) using the light diffusion through the canopy as a function of the successional stage. For this purpose, we estimated the K coefficient, a parameter that relates the normalized difference vegetation index (NDVI) to LAI, based on photosynthetically active radiation (PAR) and solar radiation. The study was conducted in the Mata Seca State Park, in southeastern Brazil, from 2012 to 2013. We defined four successional stages (very early, early, intermediate, and late) and established one optical phenology tower at one plot of 20 × 20 m per stage. Towers measured the incoming and reflected solar radiation and PAR for NDVI calculation. For each plot, we established 24 points for LAI sampling through hemispherical photographs. Because leaf cover is highly seasonal in TDFs, we determined ΔK (leaf growth phase) and K max (leaf maturity phase). We detected a strong correlation between NDVI and LAI, which is necessary for a reliable determination of the K coefficient. Both NDVI and LAI varied significantly between successional stages, indicating sensitivity to structural changes in forest regeneration. Furthermore, the K values differed between successional stages and correlated significantly with other environmental variables such as air temperature and humidity, fraction of absorbed PAR, and soil moisture. Thus, we established a model based on spectral properties of the vegetation coupled with biophysical characteristics in a TDF that makes possible to estimate LAI from NDVI values. The application of the K coefficient can improve remote estimations of forest primary productivity and gases and energy exchanges between vegetation and atmosphere

Assessing health impacts in complex eco-epidemiological settings in the humid tropics: Modular baseline health surveys

Energy Technology Data Exchange (ETDEWEB)

Winkler, Mirko S., E-mail: mirko.winkler@unibas.ch [Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel (Switzerland); University of Basel, P.O. Box, CH-4003 Basel (Switzerland); Divall, Mark J., E-mail: mdivall@shapeconsulting.org [SHAPE Consulting Ltd., Pretoria 0062 (South Africa); Krieger, Gary R., E-mail: gkrieger@newfields.com [NewFields, LLC, Denver, CO 80202 (United States); Schmidlin, Sandro, E-mail: sandro.schmidlin@gmail.com [Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel (Switzerland); University of Basel, P.O. Box, CH-4003 Basel (Switzerland); Magassouba, Mohamed L., E-mail: laminemagass@yahoo.fr [Clinique Ambroise Pare, P.O. Box, 1042 Conakry (Guinea); Knoblauch, Astrid M., E-mail: astrid.knoblauch@me.com [SHAPE Consulting Ltd., Pretoria 0062 (South Africa); Singer, Burton H., E-mail: bhsinger@epi.ufl.edu [Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610 (United States); Utzinger, Juerg, E-mail: juerg.utzinger@unibas.ch [Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, P.O. Box, CH-4002 Basel (Switzerland); University of Basel, P.O. Box, CH-4003 Basel (Switzerland)

2012-02-15

The quantitative assessment of health impacts has been identified as a crucial feature for realising the full potential of health impact assessment (HIA). In settings where demographic and health data are notoriously scarce, but there is a broad range of ascertainable ecological, environmental, epidemiological and socioeconomic information, a diverse toolkit of data collection strategies becomes relevant for the mainly small-area impacts of interest. We present a modular, cross-sectional baseline health survey study design, which has been developed for HIA of industrial development projects in the humid tropics. The modular nature of our toolkit allows our methodology to be readily adapted to the prevailing eco-epidemiological characteristics of a given project setting. Central to our design is a broad set of key performance indicators, covering a multiplicity of health outcomes and determinants at different levels and scales. We present experience and key findings from our modular baseline health survey methodology employed in 14 selected sentinel sites within an iron ore mining project in the Republic of Guinea. We argue that our methodology is a generic example of rapid evidence assembly in difficult-to-reach localities, where improvement of the predictive validity of the assessment and establishment of a benchmark for longitudinal monitoring of project impacts and mitigation efforts is needed.

Assessing health impacts in complex eco-epidemiological settings in the humid tropics: Modular baseline health surveys

International Nuclear Information System (INIS)

Winkler, Mirko S.; Divall, Mark J.; Krieger, Gary R.; Schmidlin, Sandro; Magassouba, Mohamed L.; Knoblauch, Astrid M.; Singer, Burton H.; Utzinger, Jürg

2012-01-01

The quantitative assessment of health impacts has been identified as a crucial feature for realising the full potential of health impact assessment (HIA). In settings where demographic and health data are notoriously scarce, but there is a broad range of ascertainable ecological, environmental, epidemiological and socioeconomic information, a diverse toolkit of data collection strategies becomes relevant for the mainly small-area impacts of interest. We present a modular, cross-sectional baseline health survey study design, which has been developed for HIA of industrial development projects in the humid tropics. The modular nature of our toolkit allows our methodology to be readily adapted to the prevailing eco-epidemiological characteristics of a given project setting. Central to our design is a broad set of key performance indicators, covering a multiplicity of health outcomes and determinants at different levels and scales. We present experience and key findings from our modular baseline health survey methodology employed in 14 selected sentinel sites within an iron ore mining project in the Republic of Guinea. We argue that our methodology is a generic example of rapid evidence assembly in difficult-to-reach localities, where improvement of the predictive validity of the assessment and establishment of a benchmark for longitudinal monitoring of project impacts and mitigation efforts is needed.

Vegetable milks and their fermented derivative products

Directory of Open Access Journals (Sweden)

Neus Bernat

2014-04-01

Full Text Available The so-called vegetable milks are in the spotlight thanks to their lactose-free, animal protein-free and cholesterol-free features which fit well with the current demand for healthy food products. Nevertheless, and with the exception of soya, little information is available about these types of milks and their derivatives. The aims of this review, therefore, are to: highlight the main nutritional benefits of the nut and cereal vegetable milks available on the market, fermented or not; describe the basic processing steps involved in their manufacturing process; and analyze the major problems affecting their overall quality, together with the current feasible solutions. On the basis of the information gathered, vegetable milks and their derivatives have excellent nutritional properties which provide them a high potential and positive market expectation. Nevertheless, optimal processing conditions for each raw material or the application of new technologies have to be researched in order to improve the quality of the products. Hence, further studies need to be developed to ensure the physical stability of the products throughout their whole shelf-life. These studies would also allow for a reduction in the amount of additives (hydrocolloids and/or emulsifiers and thus reduce the cost of the products. In the particular case of fermented products, the use of starters which are able to both improve the quality (by synthesizing enhanced flavors and providing optimal textures and exert health benefits for consumers (i.e. probiotics is the main challenge to be faced in future studies.

Associations between soil variables and vegetation structure and composition of Caribbean dry forests

Science.gov (United States)

Elvia M. Melendez-Ackerman; Julissa Rojas-Sandoval; Danny S. Fernandez; Grizelle Gonzalez; Hana Lopez; Jose Sustache; Mariely Morales; Miguel Garcia-Bermudez; Susan Aragon

2016-01-01

Soil–vegetation associations have been understudied in tropical dry forests when compared to the amount of extant research on this issue in tropical wet forests. Recent studies assert that vegetation in tropical dry forests is highly heterogeneous and that soil variability may be a contributing factor. In this study, we evaluated the relationship between soil variables...

Postglacial fire history and interactions with vegetation and climate in southwestern Yunnan Province of China

Science.gov (United States)

Xiao, Xiayun; Haberle, Simon G.; Shen, Ji; Xue, Bin; Burrows, Mark; Wang, Sumin

2017-06-01

A high-resolution, continuous 18.5 kyr (1 kyr = 1000 cal yr BP) macroscopic charcoal record from Qinghai Lake in southwestern Yunnan Province, China, reveals postglacial fire frequency and variability history. The results show that three periods with high-frequency and high-severity fires occurred during the periods 18.5-15.0, 13.0-11.5, and 4.3-0.8 ka, respectively. This record was compared with major pollen taxa and pollen diversity indices from the same core, and tentatively related to the regional climate proxy records with the aim to separate climate- from human-induced fire activity, and discuss vegetation-fire-climate interactions. The results suggest that fire was mainly controlled by climate before 4.3 ka and by the combined actions of climate and humans after 4.3 ka. Before 4.3 ka, high fire activity corresponded to cold and dry climatic conditions, while warm and humid climatic conditions brought infrequent and weak fires. Fire was an important disturbance factor and played an important role in forest dynamics around the study area. Vegetation responses to fire after 4.3 ka are not consistent with those before 4.3 ka, suggesting that human influence on vegetation and fire regimes may have become more prevalent after 4.3 ka. The comparisons between fire activity and vegetation reveal that evergreen oaks are flammable plants and fire-tolerant taxa. Alnus is a fire-adapted taxon and a nonflammable plant, but density of Alnus forest is a key factor to decide its fire resistance. The forests dominated by Lithocarpus/Castanopsis and/or tropical trees and shrubs are not easy to ignite, but Lithocarpus/Castanopsis and tropical trees and shrubs are fire-sensitive taxa. Fire appears to be unfavourable to plant diversity in the study area.

Viability of microcomputed tomography to study tropical marine worm galleries in humid muddy sediments

Energy Technology Data Exchange (ETDEWEB)

Pennafirme, Simone F., E-mail: sipennafirme@gmail.com [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Biologia. Dept. de Biologia Marinha; Machado, Alessandra S.; Lima, Inaya; Suzuki, Katia N.; Lopes, Ricardo T., E-mail: machado@lin.ufrj.br, E-mail: inaya@lin.ufrj.br, E-mail: norisuzuki6@yahoo.com.br, E-mail: ricardo@lin.ufj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), RJ (Brazil). Lab. de Instrumentacao Nuclear

2013-07-01

within the sediment, decreasing the accuracy of the wormholes identification. To sum up, the images show that the investigation of small tropical marine worm's galleries within humid muddy sediments is possible by this X-ray image technique. The final 3D images were performed in two different pixel sizes (23.83 μm and 30.08 μm), which allow the identification/quantification of galleries and, therefore, supporting the improvement of knowledge on bioturbation processes in marine benthic systems. (author)

Viability of microcomputed tomography to study tropical marine worm galleries in humid muddy sediments

International Nuclear Information System (INIS)

Pennafirme, Simone F.; Machado, Alessandra S.; Lima, Inaya; Suzuki, Katia N.; Lopes, Ricardo T.

2013-01-01

sediment, decreasing the accuracy of the wormholes identification. To sum up, the images show that the investigation of small tropical marine worm's galleries within humid muddy sediments is possible by this X-ray image technique. The final 3D images were performed in two different pixel sizes (23.83 μm and 30.08 μm), which allow the identification/quantification of galleries and, therefore, supporting the improvement of knowledge on bioturbation processes in marine benthic systems. (author)

Calculation of Individual Tree Water Use in a Bornean Tropical Rain Forest Using Individual-Based Dynamic Vegetation Model SEIB-DGVM

Science.gov (United States)

Nakai, T.; Kumagai, T.; Saito, T.; Matsumoto, K.; Kume, T.; Nakagawa, M.; Sato, H.

2015-12-01

Bornean tropical rain forests are among the moistest biomes of the world with abundant rainfall throughout the year, and considered to be vulnerable to a change in the rainfall regime; e.g., high tree mortality was reported in such forests induced by a severe drought associated with the ENSO event in 1997-1998. In order to assess the effect (risk) of future climate change on eco-hydrology in such tropical rain forests, it is important to understand the water use of trees individually, because the vulnerability or mortality of trees against climate change can depend on the size of trees. Therefore, we refined the Spatially Explicit Individual-Based Dynamic Global Vegetation Model (SEIB-DGVM) so that the transpiration and its control by stomata are calculated for each individual tree. By using this model, we simulated the transpiration of each tree and its DBH-size dependency, and successfully reproduced the measured data of sap flow of trees and eddy covariance flux data obtained in a Bornean lowland tropical rain forest in Lambir Hills National Park, Sarawak, Malaysia.

Effect of Temperature and Relative Humidity on the Growth of ...

African Journals Online (AJOL)

were used to determine the temperature effect on the growth of H. fulvum. Maximum growth of H. ... The fungus showed maximum growth at 92.5 and 100% relative humidity. .... recommended that fruits and vegetables should be stored at low ...

Minimizing Risks of Invasive Alien Plant Species in Tropical Production Forest Management

Directory of Open Access Journals (Sweden)

Michael Padmanaba

2014-08-01

Full Text Available Timber production is the most pervasive human impact on tropical forests, but studies of logging impacts have largely focused on timber species and vertebrates. This review focuses on the risk from invasive alien plant species, which has been frequently neglected in production forest management in the tropics. Our literature search resulted in 114 publications with relevant information, including books, book chapters, reports and papers. Examples of both invasions by aliens into tropical production forests and plantation forests as sources of invasions are presented. We discuss species traits and processes affecting spread and invasion, and silvicultural practices that favor invasions. We also highlight potential impacts of invasive plant species and discuss options for managing them in production forests. We suggest that future forestry practices need to reduce the risks of plant invasions by conducting surveillance for invasive species; minimizing canopy opening during harvesting; encouraging rapid canopy closure in plantations; minimizing the width of access roads; and ensuring that vehicles and other equipment are not transporting seeds of invasive species. Potential invasive species should not be planted within dispersal range of production forests. In invasive species management, forewarned is forearmed.

On the comparisons of tropical relative humidity in the lower and middle troposphere among COSMIC radio occultations and MERRA and ECMWF data sets

Science.gov (United States)

Vergados, P.; Mannucci, A. J.; Ao, C. O.; Jiang, J. H.; Su, H.

2015-04-01

The spatial variability of the tropical tropospheric relative humidity (RH) throughout the vertical extent of the troposphere is examined using Global Positioning System Radio Occultation (GPSRO) observations from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) mission. These high vertical resolution observations capture the detailed structure and moisture budget of the Hadley Cell circulation. We compare the COSMIC observations with the European Center for Medium-range Weather Forecast (ECMWF) Reanalysis Interim (ERA-Interim) and the Modern-Era Retrospective analysis for Research and Applications (MERRA) climatologies. Qualitatively, the spatial pattern of RH in all data sets matches up remarkably well, capturing distinct features of the general circulation. However, RH discrepancies exist between ERA-Interim and COSMIC data sets that are noticeable across the tropical boundary layer. Specifically, ERA-Interim shows a drier Intertropical Convergence Zone (ITCZ) by 15-20% compared to both COSMIC and MERRA data sets, but this difference decreases with altitude. Unlike ECMWF, MERRA shows an excellent agreement with the COSMIC observations except above 400 hPa, where GPSRO observations capture drier air by 5-10%. RH climatologies were also used to evaluate intraseasonal variability. The results indicate that the tropical middle troposphere at ±5-25° is most sensitive to seasonal variations. COSMIC and MERRA data sets capture the same magnitude of the seasonal variability, but ERA-Interim shows a weaker seasonal fluctuation up to 10% in the middle troposphere inside the dry air subsidence regions of the Hadley Cell. Over the ITCZ, RH varies by maximum 9% between winter and summer.

Agriculture at the Edge: Landscape Variability of Soil C Stocks and Fluxes in the Tropical Andes

Science.gov (United States)

Riveros-Iregui, D. A.; Peña, C.

2015-12-01

Paramos, or tropical alpine grasslands occurring right above the forest tree-line (2,800 - 4,700 m), are among the most transformed landscapes in the humid tropics. In the Tropical Andes, Paramos form an archipelago-like pattern from Northern Colombia to Central Peru that effectively captures atmospheric moisture originated in the Amazon-Orinoco basins, while marking the highest altitude capable of sustaining vegetation growth (i.e., 'the edge'). This study investigates the role of land management on mediating soil carbon stocks and fluxes in Paramo ecosystems of the Eastern Cordillera of Colombia. Observations were collected at a Paramo site strongly modified by land use change, including active potato plantations, pasture, tillage, and land abandonment. Results show that undisturbed Paramos soils have high total organic carbon (TOC), high soil water content (SWC), and low soil CO2 efflux (RS) rates. However, Paramo soils that experience human intervention show lower TOC, higher and more variable RS rates, and lower SWC. This study demonstrates that changes in land use in Paramos affect differentially the accumulation and exchange of soil carbon with the atmosphere and offers implications for management and protection strategies of what has been deemed the fastest evolving biodiversity ecosystem in the world.

Phenology and biomass production of adapted and non-adapted tropical corn populations in Central Iowa

Science.gov (United States)

Biofuel production in the Midwestern United States has largely focused on corn (Zea mays L.) grain for ethanol production and more recently, corn stover for lignocellulosic ethanol. As an alternative to conventional corn, tropical corn populations have been evaluated. Tropical corn is the term used ...

Review article: Vegetative growth, reproduction, browse production ...

African Journals Online (AJOL)

Vegetative growth, reproduction, browse production and response to tree clearing of ... water stress, soil nutrient availability, carbohydrate reserves, plant hormones, ... animal-plant interactions) of woody plants in various savanna ecosystems.

Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

Science.gov (United States)

Fabien H. Wagner; Bruno Herault; Damien Bonal; Clement Stahl; Liana O. Anderson; Timothy R. Baker; Gabriel Sebastian Becker; Hans Beeckman; Danilo Boanerges Souza; Paulo Cesar Botosso; David M. J. S. Bowman; Achim Brauning; Benjamin Brede; Foster Irving Brown; Jesus Julio Camarero; Plinio Barbosa Camargo; Fernanda C. G. Cardoso; Fabricio Alvim Carvalho; Wendeson Castro; Rubens Koloski Chagas; Jerome Chave; Emmanuel N. Chidumayo; Deborah A. Clark; Flavia Regina Capellotto Costa; Camille Couralet; Paulo Henrique da Silva Mauricio; Helmut Dalitz; Vinicius Resende de Castro; Jacanan Eloisa de Freitas Milani; Edilson Consuelo de Oliveira; Luciano de Souza Arruda; Jean-Louis Devineau; David M. Drew; Oliver Dunisch; Giselda Durigan; Elisha Elifuraha; Marcio Fedele; Ligia Ferreira Fedele; Afonso Figueiredo Filho; Cesar Augusto Guimaraes Finger; Augusto Cesar Franco; Joao Lima Freitas Junior; Franklin Galvao; Aster Gebrekirstos; Robert Gliniars; Paulo Mauricio Lima de Alencastro Graca; Anthony D. Griffiths; James Grogan; Kaiyu Guan; Jurgen Homeier; Maria Raquel Kanieski; Lip Khoon Kho; Jennifer Koenig; Sintia Valerio Kohler; Julia Krepkowski; Jose Pires Lemos-Filho; Diana Lieberman; Milton Eugene Lieberman; Claudio Sergio Lisi; Tomaz Longhi Santos; Jose Luis Lopez Ayala; Eduardo Eijji Maeda; Yadvinder Malhi; Vivian R. B. Maria; Marcia C. M. Marques; Renato Marques; Hector Maza Chamba; Lawrence Mbwambo; Karina Liana Lisboa Melgaco; Hooz Angela Mendivelso; Brett P. Murphy; Joseph O' Brien; Steven F. Oberbauer; Naoki Okada; Raphael Pelissier; Lynda D. Prior; Fidel Alejandro Roig; Michael Ross; Davi Rodrigo Rossatto; Vivien Rossi; Lucy Rowland; Ervan Rutishauser; Hellen Santana; Mark Schulze; Diogo Selhorst; Williamar Rodrigues Silva; Marcos Silveira; Susanne Spannl; Michael D. Swaine; Jose Julio Toledo; Marcos Miranda Toledo; Marisol Toledo; Takeshi Toma; Mario Tomazello Filho; Juan Ignacio Valdez Hernandez; Jan Verbesselt; Simone Aparecida Vieira; Gregoire Vincent; Carolina Volkmer de Castilho; Franziska Volland; Martin Worbes; Magda Lea Bolzan Zanon; Luiz E. O. C. Aragao

2016-01-01

The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter...

Why do forest products become less available? A pan-tropical comparison of drivers of forest-resource degradation

OpenAIRE

Hermans, Kathleen; Gerstner, Katharina; Geijzendorffer, Ilse R.; Herold, Martin; Seppelt, Ralf; Wunder, Sven

2016-01-01

Forest products provide an important source of income and wellbeing for rural smallholder communities across the tropics. Although tropical forest products frequently become over-exploited, only few studies explicitly address the dynamics of degradation in response to socio-economic drivers. Our study addresses this gap by analyzing the factors driving changes in tropical forest products in the perception of rural smallholder communities. Using the poverty and environment network global datas...

Early to Middle Eocene vegetation dynamics at the Wilkes Land Margin (Antarctica)

NARCIS (Netherlands)

Contreras, L.; Pross, J.; Bijl, P.K.; Koutsodendris, A.; Raine, J.I.; van de Schootbrugge, B.; Brinkhuis, H.

2013-01-01

The early Eocene epoch was characterized by extreme global warmth, which in terrestrial settings was characterized by an expansion of near-tropical vegetation belts into the high latitudes. During the middle to late Eocene, global cooling caused the retreat of tropical vegetation to lower latitudes.

EFFECT OF LOW-TEMPERATURE HYGROTHERMAL PROCESSING ON FORMS OF ASSOCIATION OF MOISTURE IN RICE-VEGETABLE MIXTURE WITH HYDROBIONTS

Directory of Open Access Journals (Sweden)

N. S. Rodionova

2014-01-01

Full Text Available Summary. In the catering industry common combination of rice, vegetable raw materials: onion and carrot, and aquatic organisms: fish, squid, which allows you to get a dish with high consumer properties. The article investigated the influence of the amount of water introduced by the ratio of free and bound moisture in food samples obtained using the low temperature thermo-humidity treatment, compared with the control. Found that for all drawing and vegetable mixture with squid, adding water in an amount exceeding 12.0 % of the total weight of the meal increases the mass fraction of free moisture. For rice-vegetable mixture with carp introduction of additional water is not recommended, since the introduction of water even in the amount of 5 % of the total weight of the meal increases the mass fraction of free moisture. The data indicate that the use of low-temperature thermal treatment of the samples humid pre vacuum packaging technology helps to reduce finished product weight loss, due to the amount of free moisture conservation while increasing the mass of bound water that helps to ensure better consistency of the final product, increase the shelf life and exit semis.

New recommendations for building in tropical climates

Energy Technology Data Exchange (ETDEWEB)

Waal, H.B. de (ISOVER BV, Cappelle a/d IJssel (Netherlands))

1993-07-01

Traditional recommendations for building a thermally efficient or comfortable building in a tropical climate are briefly summarized. They suffer from three main drawbacks; they are not quantitative, partly incorrect and only for two climates; the hot dry and the warm humid. A new climate classification, made up of forty tropical climates is presented. Eight building elements, which affect the thermal system of a building, are distinguished. The method by which the new recommendations are derived, is discussed. The new recommendations are briefly presented. (Author)

Mediterranean biomes: Evolution of their vegetation, floras and climate

Science.gov (United States)

Rundel, Philip W.; Arroyo, Mary T.K.; Cowling, R.M.; Keeley, J. E.; Lamont, B.B.; Vargas, Pablo

2016-01-01

Mediterranean-type ecosystems (MTEs) possess the highest levels of plant species richness in the world outside of the wet tropics. Sclerophyll vegetation similar to today’s mediterranean-type shrublands was already present on oligotrophic soils in the wet and humid climate of the Cretaceous, with fire-adapted Paleogene lineages in southwestern Australia and the Cape Region. The novel MTC seasonality present since the mid-Miocene has allowed colonization of MTEs from a regional species pool with associated diversification. Fire persistence has been a primary driving factor for speciation in four of the five regions. Understanding the regional patterns of plant species diversity among the MTEs involves complex interactions of geologic and climatic histories for each region as well as ecological factors that have promoted diversification in the Neogene and Quaternary. A critical element of species richness for many MTE lineages has been their ability to speciate and persist at fine spatial scales, with low rates of extinction.

Optimal use of land surface temperature data to detect changes in tropical forest cover

Science.gov (United States)

Van Leeuwen, T. T.; Frank, A. J.; Jin, Y.; Smyth, P.; Goulden, M.; van der Werf, G.; Randerson, J. T.

2011-12-01

Rapid and accurate assessment of global forest cover change is needed to focus conservation efforts and to better understand how deforestation is contributing to the build up of atmospheric CO2. Here we examined different ways to use remotely sensed land surface temperature (LST) to detect changes in tropical forest cover. In our analysis we used monthly 0.05×0.05 degree Terra MODerate Resolution Imaging Spectroradiometer (MODIS) observations of LST and PRODES (Program for the Estimation of Deforestation in the Brazilian Amazon) estimates of forest cover change. We also compared MODIS LST observations with an independent estimate of forest cover loss derived from MODIS and Landsat observations. Our study domain of approximately 10×10 degree included most of the Brazilian state of Mato Grosso. For optimal use of LST data to detect changes in tropical forest cover in our study area, we found that using data sampled during the end of the dry season (~1-2 months after minimum monthly precipitation) had the greatest predictive skill. During this part of the year, precipitation was low, surface humidity was at a minimum, and the difference between day and night LST was the largest. We used this information to develop a simple temporal sampling algorithm appropriate for use in pan-tropical deforestation classifiers. Combined with the normalized difference vegetation index (NDVI), a logistic regression model using day-night LST did moderately well at predicting forest cover change. Annual changes in day-night LST difference decreased during 2006-2009 relative to 2001-2005 in many regions within the Amazon, providing independent confirmation of lower deforestation levels during the latter part of this decade as reported by PRODES. The use of day-night LST differences may be particularly valuable for use with satellites that do not have spectral bands that allow for the estimation of NDVI or other vegetation indices.

NOAA JPSS Advanced Technology Microwave Sounder (ATMS)-based Tropical Cyclone (TC) Products from NDE

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The JPSS Microwave Sounder-based Tropical Cyclone (TC) Products provide estimates of tropical cyclone maximum wind speed, minimum sea level pressure, radii of 34,...

OPTIMIZATION OF VEGETABLE WASTES FOR LACTIC ACID PRODUCTION: A LABORATORY SCALE APPROACH

Directory of Open Access Journals (Sweden)

Sailaja Daharbha

2015-04-01

Full Text Available Vegetables wastes are organic materials which are not utilized as vegetables and are discarded at all stages of production, processing and marketing. These wastes form a major part of municipal solid wastes and are cause of foul smell and growth of microorganisms due to their high organic contents. The vegetable wastes can be utilized in many different ways to produces different products. We have shown that they can be utilized for production of lactic acid using anaerobic digestion. The 2nd day was the optimum day for recovery of lactic acid while 1:1 ratio of slurry and water was found to the best ratio for production of lactic acid from vegetable wastes. Effect of salts on lactic acid was also studied and it was found that the production decreased in all the concentrations of salts.

Interactions between atmospheric circulation, nutrient deposition, and tropical forest primary production (Invited)

Science.gov (United States)

Randerson, J. T.; Chen, Y.; Rogers, B. M.; Morton, D. C.; van der Werf, G.; Mahowald, N. M.

2010-12-01

Tropical forests influence regional and global climate by means of several pathways, including by modifying surface energy exchange and by forming clouds. High levels of precipitation, leaching, and soil weathering limit nutrient availability in these ecosystems. Phosphorus (P) is a key element limiting net primary production, and in some areas, including forests recovering from prior disturbance, nitrogen (N) also may limit some components of production. Here we quantified atmospheric P and N inputs to these forests from fires using satellite-derived estimates of emissions and atmospheric models. In Africa and South America, cross-biome transport of fire-emitted aerosols and reactive N gases from savannas and areas near the deforestation frontier increased deposition of P and N in interior forests. Equatorward atmospheric transport during the dry (fire) season in one hemisphere was linked with surface winds moving toward the inter-tropical convergence zone (ITCZ) in the other hemisphere. Deposition levels were higher in tropical forests in Africa than in South America because of large savanna areas with high levels of fire emissions in both southern and northern Africa. We conclude by describing a potential feedback loop by which equatorward transport of fire emissions, dust, and spores sustains the productivity of tropical forests. We specifically assessed evidence that savanna-to-forest atmospheric transport of nutrients increases forest productivity, height, and rates of evapotranspiration (ET). In parallel, we examined the degree to which increases in ET and surface roughness in tropical forests have the potential to strengthen several components of the Hadley circulation, including deep convection, equatorward return flow (near the surface), and the intensity of seasonal drought in the subtropics (thereby increasing fires). These interactions are important for understanding biogeochemical - climate interactions on millennial timescales and for quantifying how

Evaluation of Production and Carbon Benefit of Different Vegetables

Directory of Open Access Journals (Sweden)

HU Liang

2016-01-01

Full Text Available This study analyzed environmental and economic benefits of 8 types of vegetables in 4 different farms over 3 years. The specific results were as follows:(1The input-output ratio and carbon footprint of organic production mode was 18.5% and 87.4% of that of pollution-free mode, respectively; (2Fertilizer and power consumption was the main source of carbon emissions, accounting for 58.76% and 16.67% of total carbon emissions, respectively; (3There were positive correlations between N fertilizer and both carbon emissions and carbon footprint. In other words, higher use of N fertilizer resulted in higher carbon emissions and carbon footprint; (4 When organic fertilizers use reached 122 352 kg·hm-2, the crop production could reach the maximum under organic mode. Under the mode of pollution-free production, when agricultural chemicals input reached 20 103 yuan·hm-2, leafy vegetable production could reach the maximum. Therefore, to increase production and reduce carbon emissions in the process of vegetable production, the main approach was to use organic mode, increase the quantity of organic fertilizer, instead of the use of inorganic N fertilizer and other agricultural chemicals and establish water-saving irrigation system for electricity efficiency.

Children's Perceptions and Learning about Tropical Rainforests: An Analysis of Their Drawings

Science.gov (United States)

Bowker, Rob

2007-01-01

This study analysed 9 to 11 year old children's drawings of tropical rainforests immediately before and after a visit to the Humid Tropics Biome at the Eden Project, Cornwall, UK. A theoretical framework derived from considerations of informal learning and constructivism was used as a basis to develop a methodology to interpret the children's…

Wireless sensor for temperature and humidity measurement

Science.gov (United States)

Drumea, Andrei; Svasta, Paul

2010-11-01

Temperature and humidity sensors have a broad range of applications, from heating and ventilation of houses to controlled drying of fruits, vegetables or meat in food industry. Modern sensors are integrated devices, usually MEMS, factory-calibrated and with digital output of measured parameters. They can have power down modes for reduced energy consumption. Such an integrated device allows the implementation of a battery powered wireless sensor when coupled with a low power microcontroller and a radio subsystem. A radio sensor can work independently or together with others in a radio network. Presented paper focuses mainly on measurement and construction aspects of sensors for temperature and humidity designed and implemented by authors; network aspects (communication between two or more sensors) are not analyzed.

Effects of temporal changes in climate variables on crop production ...

African Journals Online (AJOL)

Climate variability and change have been implicated to have significant impacts on global and regional food production particularly the common stable food crops performance in tropical sub-humid climatic zone. However, the extent and nature of these impacts still remain uncertain. In this study, records of crop yields and ...

Design of evaporative-cooling roof for decreasing air temperatures in buildings in the humid tropics

Science.gov (United States)

Kindangen, Jefrey I.; Umboh, Markus K.

2017-03-01

This subject points to assess the benefits of the evaporative-cooling roof, particularly for buildings with corrugated zinc roofs. In Manado, many buildings have roofed with corrugated zinc sheets; because this material is truly practical, easy and economical application. In general, to achieve thermal comfort in buildings in a humid tropical climate, people applying cross ventilation to cool the air in the room and avoid overheating. Cross ventilation is a very popular path to achieve thermal comfort; yet, at that place are other techniques that allow reducing the problem of excessive high temperature in the room in the constructions. This study emphasizes applications of the evaporative-cooling roof. Spraying water on the surface of the ceiling has been executed on the test cell and the reuse of water after being sprayed and cooled once more by applying a heat exchanger. Initial results indicate a reliable design and successfully meet the target as an effective evaporative-cooling roof technique. Application of water spraying automatic and cooling water installations can work optimally and can be an optimal model for the cooling roof as one of the green technologies. The role of heat exchangers can lower the temperature of the water from spraying the surface of the ceiling, which has become a hot, down an average of 0.77° C. The mass flow rate of the cooling water is approximately 1.106 kg/h and the rate of heat flow is around 515 Watt, depend on the site.

Enzymes inhibitory and radical scavenging potentials of two selected tropical vegetable (Moringa oleifera and Telfairia occidentalis leaves relevant to type 2 diabetes mellitus

Directory of Open Access Journals (Sweden)

Tajudeen O. Jimoh

Full Text Available ABSTRACT Moringa oleifera Lam., Moringaceae, and Telfairia occidentalis Hook. f., Curcubitaceae, leaves are two tropical vegetables of medicinal properties. In this study, the inhibitory activities and the radical scavenging potentials of these vegetables on relevant enzymes of type 2-diabetes (α-amylase and α-glucosidase were evaluated in vitro. HPLC-DAD was used to characterize the phenolic constituents and Fe2+-induced lipid peroxidation in rat's pancreas was investigated. Various radical scavenging properties coupled with metal chelating abilities were also determined. However, phenolic extracts from the vegetables inhibited α-amylase, α-glucosidase and chelated the tested metals (Cu2+ and Fe2+ in a concentration-dependent manner. More so, the inhibitory properties of phenolic rich extracts from these vegetables could be linked to their radical scavenging abilities. Therefore, this study may offer a promising prospect for M. oleifera and T. occidentalis leaves as a potential functional food sources in the management of type 2-diabetes mellitus.

Is the poleward migration of tropical cyclone maximum intensity associated with a poleward migration of tropical cyclone genesis?

Science.gov (United States)

Daloz, Anne Sophie; Camargo, Suzana J.

2018-01-01

A recent study showed that the global average latitude where tropical cyclones achieve their lifetime-maximum intensity has been migrating poleward at a rate of about one-half degree of latitude per decade over the last 30 years in each hemisphere. However, it does not answer a critical question: is the poleward migration of tropical cyclone lifetime-maximum intensity associated with a poleward migration of tropical cyclone genesis? In this study we will examine this question. First we analyze changes in the environmental variables associated with tropical cyclone genesis, namely entropy deficit, potential intensity, vertical wind shear, vorticity, skin temperature and specific humidity at 500 hPa in reanalysis datasets between 1980 and 2013. Then, a selection of these variables is combined into two tropical cyclone genesis indices that empirically relate tropical cyclone genesis to large-scale variables. We find a shift toward greater (smaller) average potential number of genesis at higher (lower) latitudes over most regions of the Pacific Ocean, which is consistent with a migration of tropical cyclone genesis towards higher latitudes. We then examine the global best track archive and find coherent and significant poleward shifts in mean genesis position over the Pacific Ocean basins.

Phosphate fertilisers and management for sustainable crop production in tropical acid soils

International Nuclear Information System (INIS)

Chien, S.H.; Friesen, D.K.

2000-01-01

Extensive research has been conducted over the past 25 years on the management of plant nutrients, especially N and P, for crop production on acidic infertile tropical soils. Under certain conditions, the use of indigenous phosphate rock (PR) and modified PR products, such as partially acidulated PR or compacted mixtures of PR with superphosphates, are attractive alternatives, both agronomically and economically, to the use of conventional water-soluble P fertilisers for increasing crop productivity on Oxisols and Ultisols. A combination of the effects of proper P and N management including biological N 2 fixation, judicious use of lime, and the use of acid-soil tolerant and/or P-efficient cultivars in cropping systems that enhance nutrient cycling and use efficiency, can provide an effective technology to sustainably increase crop productivity and production in tropical agro-ecosystems dominated by these acid soils. (author)

Development of livestock production in the tropics: farm and farmers’ perspectives

NARCIS (Netherlands)

Oosting, S.J.; Udo, H.M.J.; Viets, T.C.

2014-01-01

Because of an increasing demand for animal-source foods, an increasing desire to reduce poverty and an increasing need to reduce the environmental impact of livestock production, tropical farming systems with livestock must increase their productivity. An important share of the global human and

Variations of net ecosystem production due to seasonal precipitation differences in a tropical dry forest of northwest Mexico

Science.gov (United States)

Verduzco, Vivian S.; Garatuza-Payán, Jaime; Yépez, Enrico A.; Watts, Christopher J.; Rodríguez, Julio C.; Robles-Morua, Agustin; Vivoni, Enrique R.

2015-10-01

Due to their large extent and high primary productivity, tropical dry forests (TDF) are important contributors to atmospheric carbon exchanges in subtropical and tropical regions. In northwest Mexico, a bimodal precipitation regime that includes winter precipitation derived from Pacific storms and summer precipitation from the North American monsoon (NAM) couples water availability with ecosystem processes. We investigated the net ecosystem production of a TDF ecosystem using a 4.5 year record of water and carbon fluxes obtained from the eddy covariance method complemented with remotely sensed data. We identified a large CO2 efflux at the start of the summer season that is strongly related to the preceding winter precipitation and greenness. Since this CO2 efflux occurs prior to vegetation green-up, we infer that respiration is mainly due to decomposition of soil organic matter accumulated from the prior growing season. Overall, ecosystem respiration has an important effect on the net ecosystem production but can be overwhelmed by the strength of the primary productivity during the NAM. Precipitation characteristics during NAM have significant controls on sustaining carbon fixation in the TDF into the fall season. We identified that a threshold of ~350 to 400 mm of monsoon precipitation leads to a switch in the annual carbon balance in the TDF ecosystem from a net source (+102 g C/m2/yr) to a net sink (-249 g C/m2/yr). This monsoonal precipitation threshold is typically exceeded one out of every 2 years. The close coupling of winter and summer periods with respect to carbon fluxes suggests that the annual carbon balance is dependent on precipitation amounts in both seasons in TDF ecosystems.

Interactions between sire family and production environment (temperate vs. tropical) on performance and thermoregulation responses in growing pigs.

Science.gov (United States)

Rosé, R; Gilbert, H; Loyau, T; Giorgi, M; Billon, Y; Riquet, J; Renaudeau, D; Gourdine, J-L

2017-11-01

The aim of this study was to evaluate the effect of 2 climatic environments (temperate [TEMP] vs. tropical humid [TROP]) on production and thermoregulation traits in growing pigs. A backcross design involving Large White (LW; heat sensitive) and Creole (CR; heat tolerant) pigs was studied. The same 10 F LW × CR boars were mated with related LW sows in each environment. A total of 1,298 backcross pigs ( = 634 pigs from 11 batches for the TEMP environment and = 664 pigs from 12 batches for the TROP environment) were phenotyped on BW (every 15 d from wk 11 to 23 of age), voluntary feed intake (ADFI, from wk 11 to 23), backfat thickness (BFT; at wk 19 and 23), skin temperature (ST; at wk 19 and 23), and rectal temperature (RT; at wk 19, 21, and 23). The feed conversion ratio was computed for the whole test period (11 to 23 wk). The calculation of the temperature-humidity index showed an average difference of 2.4°C between the TEMP and TROP environments. The ADG and ADFI were higher in the TEMP environment than in the TROP environment (834 vs. 754 g/d and 2.20 vs. 1.80 kg/d, respectively; environment than in the TEMP environment (35.9 vs. 34.8°C for ST and 39.5 vs. 39.3°C for RT, respectively; environment interactions ( environment interaction and to detect QTL related to heat tolerance.

Speleothem carbon isotopes in the tropics: a proxy for vegetation and what they reveal about the demise of Homo floresiensis

Science.gov (United States)

Scroxton, N.; Gagan, M. K.; Ayliffe, L. K.; Hellstrom, J.; Cheng, H.; Edwards, R.; Zhao, J.; Hantoro, W. S.; Rifai, H.; Scott-Gagan, H.; Cowley, J. A.; Suwargadi, B. W.

2013-12-01

Most long-term speleothem climate records focus on δ18O (Cruz Jr. et al. 2005, Wang et al. 2005, Meckler et al. 2012, Carolin et al. 2013). In tropical regions, where temperature variability is relatively small, speleothem δ18O serves as a proxy for precipitation amount. On orbital timescales, changes in moisture source, sea level and global ice volume also influence speleothem δ18O. As both δ18O and δ13C are measured simultaneously, a wealth of potential paleoclimatic information from the δ13C records for numerous sites awaits publication. However, δ13C is less well understood as an environmental proxy, and a simple control and explanation may not be forthcoming. We present a new 92,000-year long speleothem δ13C record for Liang Luar cave in Flores, Indonesia. Here, δ13C acts as a proxy for soil CO2 production above the cave, which is strongly linked to vegetative changes. Since vegetation and soil CO2 production are closely linked to a climatic control, changes in speleothem δ13C can be considered an environmental response to climate change. The Liang Luar δ13C record mainly tracks the δ18O, indicating close affiliation between vegetation and climate. Peak vegetation cover and soil activity (lower δ13C) occur in the early Holocene. The Last Glacial Maximum does not have notably higher δ13C than Isotope Stages 3 and 5a. δ13C variability in the glacial is much higher than that in the Holocene. Differences between the δ13C and δ18O records indicate periods of vegetative change without a climatic cause. The largest increase in δ13C (8‰) during the last 90kyr occurred at 68kyr BP. This anomalous δ13C excursion represents a major loss of vegetation around Liang Luar. The last surviving non-human member of the Homo genus: Homo floresiensis, disappeared from the stratigraphic record in nearby Liang Bua cave between 17 and 10kyr BP (Roberts et al. 2009). The cause of the disappearance, (e.g. climate change, volcanic catastrophe or human competition

Climate Change and Tropical Total Lightning

Science.gov (United States)

Albrecht, R.; Petersen, W.; Buechler, D.; Goodman, S.; Blakeslee, R.; Christian, H.

2009-01-01

While global warming is regarded as a fact by many in the scientific community, its future impact remains a challenge to be determined and measured. The International Panel on Climate Change (IPCC) assessment report (IPCC, 2007) shows inconclusive answers on global rainfall trends and general agreement on a future drier climate with increased global warming. The relationship between temperature, humidity and convection is not linear and is strongly dependent on regional scale features, such as topography and land cover. Furthermore, the relationship between convective lightning production (thunderstorms) and temperature is even more complicated, being subjected to the cloud dynamics and microphysics. Total lightning (intracloud and cloud-to-ground) monitoring is a relatively new field of observation. Global and tropical total lightning began to be more extensively measured by satellites in the mid 90s. In this scope, the Lightning Imaging Sensor (LIS) onboard of the Tropical Rainfall Measurement Mission (TRMM) has been operational for over 11 years. Here we address total lightning trends observed by LIS from 1998 to 2008 in different temporal (annual and seasonal) and spatial (large and regional) scales. The observed 11-year trends are then associate to different predicted/hypothesized climate change scenarios.

Observing Seasonal and Diurnal Hydrometeorological Variability Within a Tropical Alpine Valley: Implications for Evapotranspiration

Science.gov (United States)

Hellstrom, R. A.; Mark, B. G.

2007-12-01

Conditions of glacier recession in the seasonally dry tropical Peruvian Andes motivate research to better constrain the hydrological balance in alpine valleys. There is an outstanding need to better understand the impact of the pronounced tropical hygric seasonality on energy and water budgets within pro-glacial valleys that channel glacier runoff to stream flow. This paper presents a novel embedded network installed in the glacierized Llanganuco valley of the Cordillera Blanca (9°S) comprising eight low-cost, discrete temperature and humidity microloggers ranging from 3470 to 4740 masl and an automatic weather station at 3850 masl. Data are aggregated into distinct dry and wet periods sampled from two full annual cycles (2004-2006) to explore patterns of diurnal and seasonal variability. The magnitude of diurnal solar radiation varies little within the valley between the dry and wet periods, while wet season near-surface air temperatures are cooler. Seasonally characteristic diurnal fluctuations in lapse rate partially regulate convection and humidity. Steep lapse rates during the wet season afternoon promote up-slope convection of warm, moist air and nocturnal rainfall events. Standardized grass reference evapotranspiration (ET0) was estimated using the FAO-56 algorithm of the United Nations Food and Agriculture Organization and compared with estimates of actual ET from the process-based BROOK90 model that incorporates more realistic vegetation parameters. Comparisons of composite diurnal cycles of ET for the wet and dry periods suggest about twice the daily ET0 during the dry period, attributed primarily to the 500% higher vapor pressure deficit and 20% higher daily total solar irradiance. Conversely, the near absence of rainfall during the dry season diminishes actual ET below that of the wet season by two orders of magnitude. Nearly cloud-free daylight conditions are critical for ET during the wet season. We found significant variability of ET with elevation

Using Remotely Sensed Fluorescence and Soil Moisture to Better Understand the Seasonal Cycle of Tropical Grasslands

Science.gov (United States)

Smith, Dakota Carlysle

Seasonal grasslands account for a large area of Earth's land cover. Annual and seasonal changes in these grasslands have profound impacts on Earth's carbon, energy, and water cycles. In tropical grasslands, growth is commonly water-limited and the landscape oscillates between highly productive and unproductive. As the monsoon begins, soils moisten providing dry grasses the water necessary to photosynthesize. However, along with the rain come clouds that obscure satellite products that are commonly used to study productivity in these areas. To navigate this issue, we used solar induced fluorescence (SIF) products from OCO-2 along with soil moisture products from the Soil Moisture Active Passive satellite (SMAP) to "see through" the clouds to monitor grassland productivity. To get a broader understanding of the vegetation dynamics, we used the Simple Biosphere Model (SiB4) to simulate the seasonal cycles of vegetation. In conjunction with SiB4, the remotely sensed SIF and soil moisture observations were utilized to paint a clearer picture of seasonal productivity in tropical grasslands. The remotely sensed data is not available for every place at one time or at every time for one place. Thus, the study was focused on a large area from 15° E to 35° W and from 8°S to 20°N in the African Sahel. Instead of studying productivity relative to time, we studied it relative to soil moisture. Through this investigation we found soil moisture thresholds for the emergence of grassland growth, near linear grassland growth, and maturity of grassland growth. We also found that SiB4 overestimates SIF by about a factor of two for nearly every value of soil moisture. On the whole, SiB4 does a surprisingly good job of predicting the response of seasonal growth in tropical grasslands to soil moisture. Future work will continue to integrate remotely sensed SIF & soil moisture with SiB4 to add to our growing knowledge of carbon, water, and energy cycling in tropical grasslands.

Contributions of understory and/or overstory vegetations to soil microbial PLFA and nematode diversities in Eucalyptus monocultures.

Directory of Open Access Journals (Sweden)

Jie Zhao

Full Text Available Ecological interactions between aboveground and belowground biodiversity have received many attentions in the recent decades. Although soil biodiversity declined with the decrease of plant diversity, many previous studies found plant species identities were more important than plant diversity in controlling soil biodiversity. This study focused on the responses of soil biodiversity to the altering of plant functional groups, namely overstory and understory vegetations, rather than plant diversity gradient. We conducted an experiment by removing overstory and/or understory vegetation to compare their effects on soil microbial phospholipid fatty acid (PLFA and nematode diversities in eucalyptus monocultures. Our results indicated that both overstory and understory vegetations could affect soil microbial PLFA and nematode diversities, which manifested as the decrease in Shannon-Wiener diversity index (H' and Pielou evenness index (J and the increase in Simpson dominance index (λ after vegetation removal. Soil microclimate change explained part of variance of soil biodiversity indices. Both overstory and understory vegetations positively correlated with soil microbial PLFA and nematode diversities. In addition, the alteration of soil biodiversity might be due to a mixing effect of bottom-up control and soil microclimate change after vegetation removal in the studied plantations. Given the studied ecosystem is common in humid subtropical and tropical region of the world, our findings might have great potential to extrapolate to large scales and could be conducive to ecosystem management and service.

An Integrated Use of Experimental, Modeling and Remote Sensing Techniques to Investigate Carbon and Phosphorus Dynamics in the Humid Tropics

Science.gov (United States)

Townsend, Alan R.; Asner, Gregory P.; Bustamante, Mercedes M. C.

2001-01-01

Moist tropical forests comprise one of the world's largest and most diverse biomes, and exchange more carbon, water, and energy with the atmosphere than any other ecosystem. In recent decades, tropical forests have also become one of the globe's most threatened biomes, subjected to exceptionally high rates of deforestation and land degradation. Thus, the importance of and threats to tropical forests are undeniable, yet our understanding of basic ecosystem processes in both intact and disturbed portions of the moist tropics remains poorer than for almost any other major biome. Our approach in this project was to take a multi-scale, multi-tool approach to address two different problems. First, we wanted to test if land-use driven changes in the cycles of probable limiting nutrients in forest systems were a key driver in the frequently observed pattern of declining pasture productivity and carbon stocks. Given the enormous complexity of land use change in the tropics, in which one finds a myriad of different land use types and intensities overlain on varying climates and soil types, we also wanted to see if new remote sensing techniques would allow some novel links between parameters which could be sensed remotely, and key biogeochemical variables which cannot. Second, we addressed to general questions about the role of tropical forests in the global carbon cycle. First, we used a new approach for quantifying and minimizing non-biological artifacts in the NOAA/NASA AVHRR Pathfinder time series of surface reflectance data so that we could address potential links between Amazonian forest dynamics and ENSO cycles. Second, we showed that the disequilibrium in C-13 exchanged between land and atmosphere following tropical deforestation probably has a significant impact on the use of 13-CO2 data to predict regional fluxes in the global carbon cycle.

Estimation of Global Vegetation Productivity from Global LAnd Surface Satellite Data

Directory of Open Access Journals (Sweden)

Tao Yu

2018-02-01

Full Text Available Accurately estimating vegetation productivity is important in research on terrestrial ecosystems, carbon cycles and climate change. Eight-day gross primary production (GPP and annual net primary production (NPP are contained in MODerate Resolution Imaging Spectroradiometer (MODIS products (MOD17, which are considered the first operational datasets for monitoring global vegetation productivity. However, the cloud-contaminated MODIS leaf area index (LAI and Fraction of Photosynthetically Active Radiation (FPAR retrievals may introduce some considerable errors to MODIS GPP and NPP products. In this paper, global eight-day GPP and eight-day NPP were first estimated based on Global LAnd Surface Satellite (GLASS LAI and FPAR products. Then, GPP and NPP estimates were validated by FLUXNET GPP data and BigFoot NPP data and were compared with MODIS GPP and NPP products. Compared with MODIS GPP, a time series showed that estimated GLASS GPP in our study was more temporally continuous and spatially complete with smoother trajectories. Validated with FLUXNET GPP and BigFoot NPP, we demonstrated that estimated GLASS GPP and NPP achieved higher precision for most vegetation types.

An attempt to define the sodium requirements of lactating dairy cows in a tropical environment

NARCIS (Netherlands)

Thiangtum, W.; Yawongsa, A.; Schonewille, J.T.; Rukkwamsuk, T.; Yuangklang, C.; Verstegen, M.W.A.; Hendriks, W.H.

2011-01-01

BACKGROUND: Lactating dairy cattle in the tropics may require more sodium (Na) owing to the hot and humid climatic conditions. It is unknown whether the current recommendations on Na for lactating cows can be quantitatively used in tropical countries. This study attempted to define the Na

Testing the ecotoxicology of vegetable versus mineral based lubricating oils: 1. Degradation rates using tropical marine microbes

International Nuclear Information System (INIS)

Mercurio, Philip; Burns, Kathryn A.; Negri, Andrew

2004-01-01

Vegetable-derived lubricants (VDL) might be more biodegradable than mineral-derived lubricants (MDL) due to the absence of high molecular weight aromatics, but this remains largely untested in tropical conditions. In this laboratory study, the degradation rates of 2-stroke, 4-stroke and hydraulic VDLs were compared with their MDL counterparts in the presence of mangrove and coral reef microbial communities. While MDLs were comprised largely of unresolved saturated and some aromatic hydrocarbons, their VDL counterparts contained, potentially more degradable, fatty acid methyl esters. Degradation of some VDL was observed by day 7, with the 2-stroke VDL markedly consumed by mangrove microorganisms and the hydraulic VDL degraded by both microorganism communities after this short period. All of the VDL groups were significantly more degraded than the comparable MDLs mineral oil lubricants over 14 days in the presence of either mangrove or coral reef microbial communities. In general the mangrove-sourced microorganisms more efficiently degraded the lubricants than reef-sourced microorganisms. - Vegetable-derived lubricants were more degradable than mineral oil lubricants

Testing the ecotoxicology of vegetable versus mineral based lubricating oils: 1. Degradation rates using tropical marine microbes

Energy Technology Data Exchange (ETDEWEB)

Mercurio, Philip; Burns, Kathryn A.; Negri, Andrew

2004-05-01

Vegetable-derived lubricants (VDL) might be more biodegradable than mineral-derived lubricants (MDL) due to the absence of high molecular weight aromatics, but this remains largely untested in tropical conditions. In this laboratory study, the degradation rates of 2-stroke, 4-stroke and hydraulic VDLs were compared with their MDL counterparts in the presence of mangrove and coral reef microbial communities. While MDLs were comprised largely of unresolved saturated and some aromatic hydrocarbons, their VDL counterparts contained, potentially more degradable, fatty acid methyl esters. Degradation of some VDL was observed by day 7, with the 2-stroke VDL markedly consumed by mangrove microorganisms and the hydraulic VDL degraded by both microorganism communities after this short period. All of the VDL groups were significantly more degraded than the comparable MDLs mineral oil lubricants over 14 days in the presence of either mangrove or coral reef microbial communities. In general the mangrove-sourced microorganisms more efficiently degraded the lubricants than reef-sourced microorganisms. - Vegetable-derived lubricants were more degradable than mineral oil lubricants.

ordination et classification de la vegetation des zones humides

African Journals Online (AJOL)

USER

classes des Phragmitetea Tüxen & Pressing 1942 et des Potametea Tuxen et ... ORDINATION AND CLASSIFICATION OF WETLAND VEGETATION IN ... Principal Component Analysis, Cluster .... ensemble ; ce qui a permis d'avoir une vue.

Water vapor stable isotope observations from tropical Australia

KAUST Repository

Parkes, Stephen

2015-04-01

The response of the tropical hydrological cycle to anthropogenically induced changes in radiative forcing is one of the largest discrepancies between climate models. Paleoclimate archives of the stable isotopic composition of precipitation in the tropics indicate a relationship with precipitation amount that could be exploited to study past hydroclimate and improve our knowledge of how this region responds to changes in climate forcing. Recently modelling studies of convective parameterizations fitted with water isotopes and remote sensing of water vapor isotopes in the tropics have illustrated uncertainty in the assumed relationship with rainfall amount. Therefore there is a need to collect water isotope data in the tropics that can be used to evaluate these models and help identify the relationships between the isotopic composition of meteoric waters and rainfall intensity. However, data in this region is almost non-existent. Here we present in-situ water vapor isotopic measurements and the HDO retrievals from the co-located Total Column Carbon Observing Network (TCCON) site at Darwin in Tropical Australia. The Darwin site is interestingly placed within the tropical western pacific region and is impacted upon by a clear monsoonal climate, and key climate cycles including ENSO and Madden Julian Oscillations. The analysis of the data illustrated relationships between water vapor isotopes and humidity which demonstrated the role of precipitation processes in the wet season and air mass mixing during the dry season. Further the wet season observations show complex relationships between humidity and isotopes. A simple Rayleigh distillation model was not obeyed, instead the importance of rainfall re-evaporation in generating the highly depleted signatures was demonstrated. These data potentially provide a useful tool for evaluating model parameterizations in monsoonal regions as they demonstrate relationships with precipitation processes that cannot be observed with

Microbiological quality and safety assessment in the production of moderate and high humidity cheeses

Directory of Open Access Journals (Sweden)

Denise da Fontoura Prates

2017-10-01

Full Text Available ABSTRACT: Moderate and high humidity cheeses are described as important vehicles of pathogens in many foodborne diseases outbreaks. Microbial contamination can occur in raw material or in the different steps of the product processing due to inadequate hygiene practices. Thus, the aim of this study was to evaluate the microbiological quality and safety in the production of moderate and high humidity cheese. Samples from raw milk, handlers’ hands surface, final product were collected in three cheese manufacturing plants located in southern Brazil, with different levels of sanitary control. Effectiveness of milk pasteurization was also evaluated. Thermotolerant coliforms, coagulase-positive staphylococci (CPS, Salmonella spp., and Listeria monocytogenes were evaluated. Raw milk samples showed the highest contamination levels, with enumeration of 1.1x105 most probable number (MPN mL-1 for thermotolerant coliforms, 4x105 colony-forming units (CFU mL-1 for CPS and presence of Salmonella spp. CPS were also reported in one sample of handler’s hands surface. However, only one sample of the final product was out of Brazilian regulatory standards, exceeding the limit allowed for CPS. Milk pasteurization process used in cheese preparation was effective, regardless the level of sanitary control of the industries. Results highlighted the need for better hygiene practices, in obtaining the raw milk and in the handling during the cheese manufacturing steps.

High relative humidity pre-harvest reduces post-harvest proliferation of Salmonella in tomatoes.

Science.gov (United States)

Devleesschauwer, Brecht; Marvasi, Massimiliano; Giurcanu, Mihai C; Hochmuth, George J; Speybroeck, Niko; Havelaar, Arie H; Teplitski, Max

2017-09-01

Outbreaks of human illness caused by enteric pathogens such as Salmonella are increasingly linked to the consumption of fruits and vegetables. Knowledge on the factors affecting Salmonella proliferation on fresh produce therefore becomes increasingly important to safeguard public health. Previous experiments showed a limited impact of pre-harvest production practices on Salmonella proliferation on tomatoes, but suggested a significant effect of harvest time. We explored the data from two previously published and one unpublished experiment using regression trees, which allowed overcoming the interpretational difficulties of classical statistical models with higher order interactions. We assessed the effect of harvest time by explicitly modeling the climatic conditions at harvest time and by performing confirmatory laboratory experiments. Across all datasets, regression trees confirmed the dominant effect of harvest time on Salmonella proliferation, with humidity-related factors emerging as the most important underlying climatic factors. High relative humidity the week prior to harvest was consistently associated with lower Salmonella proliferation. A controlled lab experiment confirmed that tomatoes containing their native epimicrobiota supported significantly lower Salmonella proliferation when incubated at higher humidity prior to inoculation. The complex interactions between environmental conditions and the native microbiota of the tomato crop remain to be fully understood. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development and Performance Evaluation of a Re-Circulatory Vegetable Moisturizer

Directory of Open Access Journals (Sweden)

M. O. Sunmonu

2016-08-01

Full Text Available A re-circulatory vegetable moisturizer for preventing wilting in vegetables was developed and its performance evaluation carried out. Freshly harvested Amaranthus vegetables were used for the experiments. The temperature and relative humidity were monitored daily. The vitamin A of this produce was determined at intervals of two days for 9 days. The effects of the storage parameters (temperature and relative humidity on the nutritional value of the produce were determined using statistical analysis of variance (ANOVA. Further analysis by Duncan’s New Multiple Range Test (DNMRT was carried out to compare the means. The vegetable moisturizer was evaluated by comparing the change in nutritional (vitamin A of Amaranthus vegetable with hand wetting system and no wetting condition. The results showed that the moisturizer had higher mean vitamin A content (4.93mg/100gcompared to the mean vitamin A content of the manual wetting (4.88mg/100g and no wetting condition (4.57mg/100g. The sensory characteristics showed that the Moisturizer was more desirable when compared to the manual wetting and no wetting condition after nine days. It was concluded that the Moisturizer preserved the nutritional and sensory characteristics (texture and colour better than the manual and no wetting condition as a result of lower temperature, higher relative humidity and better water draining of the Moisturizer.

Process for the production of protein enriched fractions from vegetable materials

NARCIS (Netherlands)

Dijkink, B.H.; Willemsen, J.H.A.

2006-01-01

The present invention provides a method for the production of a protein enriched fraction and a fibre enriched fraction from a vegetable material, wherein the vegetable material comprises a total fat content of 0.1 to 22.0 % by dry weight of the total vegetable material and a total starch content of

Why do forest products become less available? A pan-tropical comparison of drivers of forest-resource degradation

NARCIS (Netherlands)

Hermans, Kathleen; Gerstner, Katharina; Geijzendorffer, Ilse R.; Herold, Martin; Seppelt, Ralf; Wunder, Sven

2016-01-01

Forest products provide an important source of income and wellbeing for rural smallholder communities across the tropics. Although tropical forest products frequently become over-exploited, only few studies explicitly address the dynamics of degradation in response to socio-economic drivers. Our

Human population growth offsets climate-driven increase in woody vegetation in sub-Saharan Africa

DEFF Research Database (Denmark)

Brandt, Martin Stefan; Rasmussen, Kjeld; Peñuelas, Josep

2017-01-01

The rapidly growing human population in sub-Saharan Africa generates increasing demand for agricultural land and forest products, which presumably leads to deforestation. Conversely, a greening of African drylands has been reported, but this has been difficult to associate with changes in woody...... an increase in woody cover largely in drylands, and 11% had a decrease (2,150,000 km2), mostly in humid zones. Increases in woody cover were associated with low population growth, and were driven by increases in CO2 in the humid zones and by increases in precipitation in drylands, whereas decreases in woody...... cover were associated with high population growth. The spatially distinct pattern of these opposing trends reflects, first, the natural response of vegetation to precipitation and atmospheric CO2, and second, deforestation in humid areas, minor in size but important for ecosystem services...

How typical are the last 20,000 years of climatic and vegetation change in the tropical Andes?

Science.gov (United States)

Gosling, W. D.; Urrego, D. H.; Hanselman, J. A.; Valencia, B.; Bush, M. B.; Silman, M. R.

2006-12-01

A consensus of global circulation models highlights the southern tropical Andes as the biodiversity hotspot most likely to experience biome shift in the next century. The pace of the ongoing change finds its nearest parallel in that of the Younger Dryas at high latitudes. However, in the tropical Andes of Peru and Bolivia we find that there was no such rapid temperature change within the last 40,000 years. Rates of temperature change across the deglacial interval (which may begin as early as c. 22,000 cal. yr BP) are one to two orders of magnitude slower than those forecasted for the next century, and differed little from those of the full glacial. Indeed, the fastest rates of vegetation change are responses to Holocene drought and human activity, not Pleistocene/Holocene warming. Sedimentary data from long records on the Altiplano provide records of earlier interglacials (MIS 5e, 7 and 9), but do not have the chronological control to provide assessments of rate of change. Nevertheless, those records do provide evidence of marked similarities in the development of each interglacial, with some divergence seen at full interglacial conditions.

Farmers' Perception towards Organic-based Vegetable Produc-tion ...

African Journals Online (AJOL)

It is well established that organic farming is a production system that sustain the health of the soils, ecosystems and people. This study assessed the small-scale farmers' perception towards organic based vegetable production in Ilaro agricultural zone of Ogun state, Nigeria. A multi-stage sampling procedure was used in the ...

Denitrification activity in mangrove sediments varies with associated vegetation

Digital Repository Service at National Institute of Oceanography (India)

Fernandes, S.O.; Dutta, P.; Gonsalves, M.J.B.D.; Bonin, P.C.; LokaBharathi, P.A.

. Eng.: 95; 2016; 671-681 Denitrification activity in mangrove sediments varies with associated vegetation Sheryl Oliveira Fernandes a, #, Pinky Dutta b, Maria-Judith Gonsalves a, Patricia C. Bonin c, P. A. LokaBharathi a, *  a Biological... in tropical and subtropical regions of the world (Giri et al., 2011). They provide a range of ecosystem services like soil formation, wood production, fish spawning grounds, carbon (C) storage and nutrient cycling (Murdiyarso et al., 2015). However, over...

Tropical Ocean Evaporation/SST Sensitivity and It's Link to Water and Energy Budget Variations During ENSO

Science.gov (United States)

Robertson, Franklin R.; Marshall, Susan; Oglesby, Robert; Roads, John; Sohn, Byung-Ju; Arnold, James E. (Technical Monitor)

2001-01-01

The continuing debate over feedback mechanisms governing tropical sea surface temperatures (SSTs) and tropical climate in general has highlighted the diversity of potential checks and balances within the climate system. Competing feedbacks due to changes in surface evaporation, water vapor, and cloud long- and shortwave radiative properties each may serve critical roles in stabilizing or destabilizing the climate system. It is also intriguing that even those climate variations having origins internal to the climate system - changes in ocean heat transport for example, apparently require complementary equilibrating effects by changes in atmospheric energy fluxes. Perhaps the best observational evidence of this is the relatively invariant nature of tropically averaged net radiation exiting the top-of-atmosphere (TOA) as measured by broadband satellite sensors over the past two decades. Thus, analyzing how these feedback mechanisms are operating within the context of current interannual variability may offer considerable insight for anticipating future climate change. In this paper we focus primarily on interannual variations of ocean evaporative fluxes and their significance for coupled water and energy cycles within the tropical climate system. In particular, we use both the da Silva estimates of surface fluxes (based on the Comprehensive Ocean Atmosphere Data Set, COADS) and numerical simulations from several global climate models to examine evaporation sensitivity to perturbations in SST associated with warm and cold ENSO events. The specific questions we address are as follows: (1) What recurring patterns of surface wind and humidity anomalies are present during ENSO and how do they combine to yield systematic evaporation anomalies?, (2) What is the resulting tropical ocean mean evaporation-SST sensitivity associated with this climate perturbation?, and (3) What role does this evaporation play in tropical heat and water balance over tropical oceanic regions? We

The Vegetable industry in China; Developments in policies, production, marketing and international trade

NARCIS (Netherlands)

Liu, Y.M.; Jinsong, C.; Zhang XiaoYong, Xiaoyong; Kamphuis, B.M.

2004-01-01

Development of Chinese vegetable industry over the past three decades. The changes of governmental vegetable policy and the major institutions involved. The major production regions in China, their leading vegetable varieties and cultivation technology. The reform of vegetable marketing structure

Plant Growth Optimization by Vegetable Production System in HI-SEAS Analog Habitat

Science.gov (United States)

Ehrlich, Joshua W.; Massa, Gioia D.; Wheeler, Raymond M.; Gill, Tracy R.; Quincy, Charles D.; Roberson, Luke B.; Binsted, Kim; Morrow, Robert C.

2017-01-01

The Vegetable Production System (Veggie) is a scientific payload designed to support plant growth for food production under microgravity conditions. The configuration of Veggie consists of an LED lighting system with modular rooting pillows designed to contain substrate media and time-release fertilizer. The pillows were designed to be watered passively using capillary principles but have typically been watered manually by the astronauts in low-Earth orbit (LEO). The design of Veggie allows cabin air to be drawn through the plant enclosure for thermal and humidity control and for supplying CO2 to the plants. Since its delivery to the International Space Station (ISS) in 2014, Veggie has undergone several experimental trials by various crews. Ground unit testing of Veggie was conducted during an 8-month Mars analog study in a semi-contained environment of a simulated habitat located at approximately 8,200 feet (2,500 m) elevation on the Mauna Loa volcano on the Island of Hawaii. The Hawaii Space Exploration Analog and Simulation (HI-SEAS) offered conditions (habitat, mission, communications, etc.) intended to simulate a planetary exploration mission. This paper provides data and analyses to show the prospect for optimized use of the current Veggie design for human habitats. Lessons learned during the study may provide opportunities for updating the system design and operational parameters for current Veggie experiments being conducted onboard the ISS and for payloads on future deep space missions.

Nitrogenous nutrients and primary production in a tropical oceanic environment

Digital Repository Service at National Institute of Oceanography (India)

Wafar, M.V.M.; Wafar, S.; Devassy, V.P.

Measurements of the concentrations of nitrogenous nutrients and primary production were made at 10 stations along 8 degrees N and 10 degrees N in the tropical oceanic Lakshadweep waters Inorganic nitrogen (NO3, NO2 and NH4) accounted for less than...

Farmers' adoption of improved vegetable production practices under ...

African Journals Online (AJOL)

STORAGESEVER

2008-12-29

Dec 29, 2008 ... the annual income of the PFs and NPFs, respectively. ... Key words: Adoption, improved vegetable, production practices, farmers and national fadama ..... so, fixed cost components such as depreciation, insurance, repairs,.

Proposition of Regression Equations to Determine Outdoor Thermal Comfort in Tropical and Humid Environment

Directory of Open Access Journals (Sweden)

Sangkertadi Sangkertadi

2012-05-01

Full Text Available This study is about field experimentation in order to construct regression equations of perception of thermalcomfort for outdoor activities under hot and humid environment. Relationships between thermal-comfort perceptions, micro climate variables (temperatures and humidity and body parameters (activity, clothing, body measure have been observed and analyzed. 180 adults, men, and women participated as samples/respondents. This study is limited for situation where wind velocity is about 1 m/s, which touch the body of the respondents/samples. From questionnaires and field measurements, three regression equations have been developed, each for activity of normal walking, brisk walking, and sitting.

Quality determinants of fruit and vegetables productions

OpenAIRE

Bruno Mezzetti; Cherubino Leonardi

2009-01-01

Nowadays, the main goal for modern horticultural production is the increase of quality. Furthermore, in consideration of the new consumer demand, always more attracted by a diet based on a larger consumption of fruit and vegetables without risks of pesticides residues and with increased nutritional value, new important features in addition to the traditional quality attributes are now requested. For a program of qualification and valorisation of modern horticultural productions, it is fundame...

Floristic Diversity of Two Zones of Humid Tropical Forest at Alto Baudó, Chocó, Colombia

Directory of Open Access Journals (Sweden)

Luis Javier Mosquera Ramos

2007-08-01

Full Text Available Between June and August of 2005 the floristic composition ≥1 cm of DAP was determined in an area of ? 0.2 ha of humid tropical forest at the localities of Pie de >Pató (05º 30' 56" N and 76º 58' 26" W and Nauca (5º 41' 6" N and 77º 00' 36" W, Alto Baudó, Chocó Colombia . En each locality an area of 0.1 ha was sampled which was divided into smaller areas of 2 x 50 cm each. A total of 1618 inidivduals were recorded represented by 257 species, 156 genres and 56 botanical families from which 842 individuals, 161 species, 108 genres and 46 families where found at Pie de Pató, and 776 individuals, 161 species, 98 genres and 45 families at Nauca. At Pie de Pató the families best represented in terms of genres were Rubiaceae (12 genres and 27 species, Arecaceae (eight genres and eight species and Bombacaceae (seven genres and ten species. At Nauca they were Rubiaceae (eleven genres and 25 species, Moraceae (eight genera and 13 species and Arecaceae (eigth genres and eight species. The richness index was of 23,75 and 24,05 for Pie de Pató and Nauca respectively. Diversity change was stimated as 4,43 for both localities. These results indicate high diversity of these forests at Alto Baudó.

Heating, Ventilation, and Air Conditioning Design Strategy for a Hot-Humid Production Builder

Energy Technology Data Exchange (ETDEWEB)

Kerrigan, P. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2014-03-01

BSC worked directly with the David Weekley Homes - Houston division to redesign three floor plans in order to locate the HVAC system in conditioned space. The purpose of this project is to develop a cost effective design for moving the HVAC system into conditioned space. In addition, BSC conducted energy analysis to calculate the most economical strategy for increasing the energy performance of future production houses. This is in preparation for the upcoming code changes in 2015. The builder wishes to develop an upgrade package that will allow for a seamless transition to the new code mandate. The following research questions were addressed by this research project: 1. What is the most cost effective, best performing and most easily replicable method of locating ducts inside conditioned space for a hot-humid production home builder that constructs one and two story single family detached residences? 2. What is a cost effective and practical method of achieving 50% source energy savings vs. the 2006 International Energy Conservation Code for a hot-humid production builder? 3. How accurate are the pre-construction whole house cost estimates compared to confirmed post construction actual cost? BSC and the builder developed a duct design strategy that employs a system of dropped ceilings and attic coffers for moving the ductwork from the vented attic to conditioned space. The furnace has been moved to either a mechanical closet in the conditioned living space or a coffered space in the attic.

Vegetation, climate and fire-dynamics in East Africa inferred from the Maundi crater pollen record from Mt Kilimanjaro during the last glacial-interglacial cycle

Science.gov (United States)

Schüler, Lisa; Hemp, Andreas; Zech, Wolfgang; Behling, Hermann

2012-04-01

The pollen, charcoal and sedimentological record from the Maundi crater, located at 2780 m elevation on the south-eastern slope of Mt Kilimanjaro, is one of the longest terrestrial records in equatorial East Africa, giving an interesting insight into the vegetation and climate dynamics back to the early last Glacial period. Our sediment record has a reliable chronology until 42 ka BP. An extrapolation of the age-depth model, as well as matching with other palaeo-records from tropical East Africa, suggest a total age of about 90 ka BP at the bottom of the record. During the last Glacial the distribution as well as the composition of the vegetation belts classified as colline savanna, submontane woodland, montane forest, ericaceous belt, and alpine vegetation changed. The early last Glacial is characterized by high amounts of Poaceae and Asteraceae pollen suggesting a climatically dry but stable phase. Based on the absence of pollen grains in samples deposited around 70 ka BP, we assume the occurrence of distinct drought periods. During the pre-LGM (Last Glacial Maximum) a higher taxa diversity of the ericaceous and montane zone is recorded and suggests a spread of forest and shrub vegetation, thus indicating a more humid period. The taxa diversity increases steadily during the recorded time span. The decent of vegetation zones indicate dry and cold conditions during the LGM and seem to have been detrimental for many taxa, especially those of the forest vegetation; however, the early last Glacial seems to have been markedly drier than the LGM. The reappearance of most of the taxa (most importantly Alchemilla, Araliaceae, Dodonea, Hagenia, Ilex, Myrsine, Moraceae, Piperaceae) during the deglacial and Holocene period suggest a shift into humid conditions. An increase in ferns and the decrease in grasses during the Holocene also indicate increasing humidity. Fire played an important role in controlling the development and elevation of the ericaceous zone and the tree

Diurnal flight behavior of Ichneumonoidea (Insecta: Hymenoptera) related to environmental factors in a tropical dry forest.

Science.gov (United States)

González-Moreno, A; Bordera, S; Leirana-Alcocer, J; Delfín-González, H

2012-06-01

The biology and behavior of insects are strongly influenced by environmental conditions such as temperature and precipitation. Because some of these factors present a within day variation, they may be causing variations on insect diurnal flight activity, but scant information exists on the issue. The aim of this work was to describe the patterns on diurnal variation of the abundance of Ichneumonoidea and their relation with relative humidity, temperature, light intensity, and wind speed. The study site was a tropical dry forest at Ría Lagartos Biosphere Reserve, Mexico; where correlations between environmental factors (relative humidity, temperature, light, and wind speed) and abundance of Ichneumonidae and Braconidae (Hymenoptera: Ichneumonoidea) were estimated. The best regression model for explaining abundance variation was selected using the second order Akaike Information Criterion. The optimum values of temperature, humidity, and light for flight activity of both families were also estimated. Ichneumonid and braconid abundances were significantly correlated to relative humidity, temperature, and light intensity; ichneumonid also showed significant correlations to wind speed. The second order Akaike Information Criterion suggests that in tropical dry conditions, relative humidity is more important that temperature for Ichneumonoidea diurnal activity. Ichneumonid wasps selected toward intermediate values of relative humidity, temperature and the lowest wind speeds; while Braconidae selected for low values of relative humidity. For light intensity, braconids presented a positive selection for moderately high values.

Eat fresh vegetables, fruit, and whole grain products | NIH MedlinePlus the Magazine

Science.gov (United States)

... please turn Javascript on. Feature: Diverticulitis "Eat fresh vegetables, fruit, and whole grain products." Past Issues / Winter 2010 ... or the diverticulitis. I once again eat fresh vegetables and fruit and whole grain products. My two episodes of ...

Conceptual differences between the bioclimatic urbanism for Europe and for the tropical humid climate

Energy Technology Data Exchange (ETDEWEB)

Corbella, O.D.; Magalhaes, M.A.A.A. [Faculdade de Arquitetura e Urbanismo, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil)

2008-05-15

This article makes part of a series of conceptual papers to continue the discussion about how architecture and urbanism interact with climate, in tropical regions. Students engaged in normal courses of architecture in tropical regions, particularly in South America, develop their knowledge based on concepts generated in the developed countries - usually related to cold environments. Consequently, these students acquire wrong ideas about urban design of open spaces. Integrating urbanism and climate in tropical countries is still very incipient as an approach and many lecturers reject it, since they prefer to continue with a more formal one, dictated by most of the dominant countries. The herein paper underlines several different concepts and perspectives that separate the two conceptions, leading to a reflection about the subject. (author)

Exclusion of soil macrofauna did not affect soil quality but increases crop yields in a sub-humid tropical maize-based system

NARCIS (Netherlands)

Paul, B.K.; Vanlauwe, B.; Hoogmoed, M.; Hurisso, T.T.; Ndabamenye, T.; Terano, Y.; Ayuke, F.O.; Pulleman, M.M.

2015-01-01

Soil macrofauna such as earthworms and termites are involved in key ecosystem functions and thus considered important for sustainable intensification of crop production. However, their contribution to tropical soil and crop performance, as well as relations with agricultural management (e.g.

Observational evidence for aerosols increasing upper tropospheric humidity

Directory of Open Access Journals (Sweden)

L. Riuttanen

2016-11-01

Full Text Available Aerosol–cloud interactions are the largest source of uncertainty in the radiative forcing of the global climate. A phenomenon not included in the estimates of the total net forcing is the potential increase in upper tropospheric humidity (UTH by anthropogenic aerosols via changes in the microphysics of deep convection. Using remote sensing data over the ocean east of China in summer, we show that increased aerosol loads are associated with an UTH increase of 2.2 ± 1.5 in units of relative humidity. We show that humidification of aerosols or other meteorological covariation is very unlikely to be the cause of this result, indicating relevance for the global climate. In tropical moist air such an UTH increase leads to a regional radiative effect of 0.5 ± 0.4 W m−2. We conclude that the effect of aerosols on UTH should be included in future studies of anthropogenic climate change and climate sensitivity.

Vegetation-climate feedbacks modulate rainfall patterns in Africa under future climate change

Science.gov (United States)

Wu, Minchao; Schurgers, Guy; Rummukainen, Markku; Smith, Benjamin; Samuelsson, Patrick; Jansson, Christer; Siltberg, Joe; May, Wilhelm

2016-07-01

Africa has been undergoing significant changes in climate and vegetation in recent decades, and continued changes may be expected over this century. Vegetation cover and composition impose important influences on the regional climate in Africa. Climate-driven changes in vegetation structure and the distribution of forests versus savannah and grassland may feed back to climate via shifts in the surface energy balance, hydrological cycle and resultant effects on surface pressure and larger-scale atmospheric circulation. We used a regional Earth system model incorporating interactive vegetation-atmosphere coupling to investigate the potential role of vegetation-mediated biophysical feedbacks on climate dynamics in Africa in an RCP8.5-based future climate scenario. The model was applied at high resolution (0.44 × 0.44°) for the CORDEX-Africa domain with boundary conditions from the CanESM2 general circulation model. We found that increased tree cover and leaf-area index (LAI) associated with a CO2 and climate-driven increase in net primary productivity, particularly over subtropical savannah areas, not only imposed important local effect on the regional climate by altering surface energy fluxes but also resulted in remote effects over central Africa by modulating the land-ocean temperature contrast, Atlantic Walker circulation and moisture inflow feeding the central African tropical rainforest region with precipitation. The vegetation-mediated feedbacks were in general negative with respect to temperature, dampening the warming trend simulated in the absence of feedbacks, and positive with respect to precipitation, enhancing rainfall reduction over the rainforest areas. Our results highlight the importance of accounting for vegetation-atmosphere interactions in climate projections for tropical and subtropical Africa.

Organic livestock production: an emerging opportunity with new challenges for producers in tropical countries.

Science.gov (United States)

Chander, M; Subrahmanyeswari, B; Mukherjee, R; Kumar, S

2011-12-01

Agrochemicals, veterinary drugs, antibiotics and improved feeds can increase the food supply while minimising production costs in various livestock production systems around the world. However, these days, quality-conscious consumers are increasingly seeking environmentally safe, chemical-residue-free healthy foods, along with product traceability and a high standard of animal welfare, which organic production methods are said to ensure. Organic production is not only a challenge for producers in developing countries, it offers new export opportunities as well. Organic agriculture is practised by 1.8 million producers in 160 countries, and production of organically grown food continues to increase steadily by 15% per year. Most tropical countries are now exporting organic agricultural products but, apart from organic beef from Brazil and Argentina, organic livestock products are yetto take off. Most trade in organic livestock products is restricted to the European Union and other developed nations. Nevertheless, tropical countries cannot afford to neglect this emerging system of animal production. Organic production is knowledge- and management-intensive. Producers must be well versed in organic production standards, principles and practices, which require a high degree of knowledge and skill. In organic production, it is not simply the final product but the whole production process that must be inspected and approved by the accredited certification bodies. Organic livestock farming is still evolving, and further research is needed to make it sustainable. In this paper, the authors review the prospects of organic animal husbandry and its possible constraints in developing and tropical countries.

EDITORIAL: Humidity sensors Humidity sensors

Science.gov (United States)

Regtien, Paul P. L.

2012-01-01

All matter is more or less hygroscopic. The moisture content varies with vapour concentration of the surrounding air and, as a consequence, most material properties change with humidity. Mechanical and thermal properties of many materials, such as the tensile strength of adhesives, stiffness of plastics, stoutness of building and packaging materials or the thermal resistivity of isolation materials, all decrease with increasing environmental humidity or cyclic humidity changes. The presence of water vapour may have a detrimental influence on many electrical constructions and systems exposed to humid air, from high-power systems to microcircuits. Water vapour penetrates through coatings, cable insulations and integrated-circuit packages, exerting a fatal influence on the performance of the enclosed systems. For these and many other applications, knowledge of the relationship between moisture content or humidity and material properties or system behaviour is indispensable. This requires hygrometers for process control or test and calibration chambers with high accuracy in the appropriate temperature and humidity range. Humidity measurement methods can roughly be categorized into four groups: water vapour removal (the mass before and after removal is measured); saturation (the air is brought to saturation and the `effort' to reach that state is measured); humidity-dependent parameters (measurement of properties of humid air with a known relation between a specific property and the vapour content, for instance the refractive index, electromagnetic spectrum and acoustic velocity); and absorption (based on the known relation between characteristic properties of non-hydrophobic materials and the amount of absorbed water from the gas to which these materials are exposed). The many basic principles to measure air humidity are described in, for instance, the extensive compilations by Wexler [1] and Sonntag [2]. Absorption-type hygrometers have small dimensions and can be

Jamaica: Test case for tropical deforestation

Energy Technology Data Exchange (ETDEWEB)

Eyre, L A

1987-01-01

Deforestation in Jamaica, according to the United Nations (FAO/UNEP) and other sources, is occurring at an annual rate of about tree percent. This is accepted by some Jamaican government agencies, but strongly disputed by others. The Ministry of Agriculture, in particular, claims that the national forested area is actually increasing rapidly. A survey of humid tropical forests in Jamaica, carried out by the author in 1986, indicates a 3.3 percent per annum rate of deforestation for 1980-1986. But, despite significant commercial lumber production, large clear fellings are rare and most modification of the forest is due to expansion of small-scale farming (including Cannabis sativa) and pastoral activity. The size of area cleared is most often 20 to 25 hectares. As uncontrolled deforestation is adversely affecting watersheds and inducing serious flooding some form of control and management is urgently required.

Recent developments in high-quality drying of vegetables, fruits, and aquatic products.

Science.gov (United States)

Zhang, Min; Chen, Huizhi; Mujumdar, Arun S; Tang, Juming; Miao, Song; Wang, Yuchuan

2017-04-13

Fresh foods like vegetables, fruits, and aquatic products have high water activity and they are highly heat-sensitive and easily degradable. Dehydration is one of the most common methods used to improve food shelf-life. However, drying methods used for food dehydration must not only be efficient and economic but also yield high-quality products based on flavor, nutrients, color, rehydration, uniformity, appearance, and texture. This paper reviews some new drying technologies developed for dehydration of vegetables, fruits, and aquatic products. These include: infrared drying, microwave drying, radio frequency drying, electrohydrodynamic drying, etc., as well as hybrid drying methods combining two or more different drying techniques. A comprehensive review of recent developments in high-quality drying of vegetables, fruits and aquatic products is presented and recommendations are made for future research.

Preparation and Humidity Sensing Properties of KCl/MCM-41 Composite

International Nuclear Information System (INIS)

Li, Liu; Lian-Yuan, Wang; Wei, Li; Li-Ying, Kou; Zhi-Cheng, Zhong; Li-Fang, Liu

2010-01-01

KCl/mobil composition of matter-41 (MCM-41) composite has been synthesized via a heat-treating process and characterized by x-ray diffraction, high resolution transmission electron microscopy, and nitrogen adsorption/desorption isotherms. In contrast with pure MCM-41, KCl/MCM-41 composite exhibits improved humidity sensing properties within the relative humidity range of 11–95%. The impedance of KCl/MCM-41 composite changes by about four orders of magnitude over the whole humidity range with the response time and the recovery times are about 30 s and 35 s, respectively. Small humidity hysteresis and good stability are also observed based on our product. These results make our product a good candidate in fabricating humidity sensors with high performances and low synthetic complexity

Distribution of tropical tropospheric water vapor

Science.gov (United States)

Sun, De-Zheng; Lindzen, Richard S.

1993-01-01

Utilizing a conceptual model for tropical convection and observational data for water vapor, the maintenance of the vertical distribution of the tropical tropospheric water vapor is discussed. While deep convection induces large-scale subsidence that constrains the turbulent downgradient mixing to within the convective boundary layer and effectively dries the troposphere through downward advection, it also pumps hydrometeors into the upper troposphere, whose subsequent evaporation appears to be the major source of moisture for the large-scale subsiding motion. The development of upper-level clouds and precipitation from these clouds may also act to dry the outflow, thus explaining the low relative humidity near the tropopause. A one-dimensional model is developed to simulate the mean vertical structure of water vapor in the tropical troposphere. It is also shown that the horizontal variation of water vapor in the tropical troposphere above the trade-wind boundary layer can be explained by the variation of a moisture source that is proportional to the amount of upper-level clouds. Implications for the nature of water vapor feedback in global warming are discussed.

Direct weakening of tropical circulations from masked CO2 radiative forcing.

Science.gov (United States)

Merlis, Timothy M

2015-10-27

Climate models robustly simulate weakened mean circulations of the tropical atmosphere in direct response to increased carbon dioxide (CO2). The direct response to CO2, defined by the response to radiative forcing in the absence of changes in sea surface temperature, affects tropical precipitation and tropical cyclone genesis, and these changes have been tied to the weakening of the mean tropical circulation. The mechanism underlying this direct CO2-forced circulation change has not been elucidated. Here, I demonstrate that this circulation weakening results from spatial structure in CO2's radiative forcing. In regions of ascending circulation, such as the intertropical convergence zone, the CO2 radiative forcing is reduced, or "masked," by deep-convective clouds and high humidity; in subsiding regions, such as the subtropics, the CO2 radiative forcing is larger because the atmosphere is drier and deep-convective clouds are infrequent. The spatial structure of the radiative forcing reduces the need for the atmosphere to transport energy. This, in turn, weakens the mass overturning of the tropical circulation. The previously unidentified mechanism is demonstrated in a hierarchy of atmospheric general circulation model simulations with altered radiative transfer to suppress the cloud masking of the radiative forcing. The mechanism depends on the climatological distribution of clouds and humidity, rather than uncertain changes in these quantities. Masked radiative forcing thereby offers an explanation for the robustness of the direct circulation weakening under increased CO2.

Correlation between soil physicochemical properties and vegetation parameters in secondary tropical forest in Sabal, Sarawak, Malaysia

Science.gov (United States)

Karyati, K.; Ipor, I. B.; Jusoh, I.; Wasli, M. E.

2018-04-01

The tree growth is influenced by soil morphological and physicochemical properties in the site. The purpose of this study was to describe correlation between soil properties under various stage secondary forests and vegetation parameters, such as floristic structure parameters and floristic diversity indices. The vegetation surveys were conducted in 5, 10, and 20 years old at secondary tropical forests in Sarawak, Malaysia. Nine sub plots sized 20 m × 20 m were established within each study site. The Pearson analysis showed that soil physicochemical properties were significantly correlated to floristic structure parameters and floristic diversity indices. The result of PCA clarified the correlation among most important soil properties, floristic structure parameters, and floristic diversity indices. The PC1 represented cation retention capacity and soil texture which were little affected by the fallow age and its also were correlated by floristic structure and diversity. The PC2 was linked to the levels of soil acidity. This property reflected the remnant effects of ash addition and fallow duration, and the significant correlation were showed among pH (H2O), floristic structure and diversity. The PC3 represented the soil compactness. The soil hardness could be influenced by fallow period and it was also correlated by floristic structure.

Seasonality of absolute humidity explains seasonality of influenza-like illness in Vietnam.

Science.gov (United States)

Thai, Pham Quang; Choisy, Marc; Duong, Tran Nhu; Thiem, Vu Dinh; Yen, Nguyen Thu; Hien, Nguyen Tran; Weiss, Daniel J; Boni, Maciej F; Horby, Peter

2015-12-01

Experimental and ecological studies have shown the role of climatic factors in driving the epidemiology of influenza. In particular, low absolute humidity (AH) has been shown to increase influenza virus transmissibility and has been identified to explain the onset of epidemics in temperate regions. Here, we aim to study the potential climatic drivers of influenza-like illness (ILI) epidemiology in Vietnam, a tropical country characterized by a high diversity of climates. We specifically focus on quantifying and explaining the seasonality of ILI. We used 18 years (1993-2010) of monthly ILI notifications aggregated by province (52) and monthly climatic variables (minimum, mean, maximum temperatures, absolute and relative humidities, rainfall and hours of sunshine) from 67 weather stations across Vietnam. Seasonalities were quantified from global wavelet spectra, using the value of the power at the period of 1 year as a measure of the intensity of seasonality. The 7 climatic time series were characterized by 534 summary statistics which were entered into a regression tree to identify factors associated with the seasonality of AH. Results were extrapolated to the global scale using simulated climatic times series from the NCEP/NCAR project. The intensity of ILI seasonality in Vietnam is best explained by the intensity of AH seasonality. We find that ILI seasonality is weak in provinces experiencing weak seasonal fluctuations in AH (annual power power >17.6). In Vietnam, AH and ILI are positively correlated. Our results identify a role for AH in driving the epidemiology of ILI in a tropical setting. However, in contrast to temperate regions, high rather than low AH is associated with increased ILI activity. Fluctuation in AH may be the climate factor that underlies and unifies the seasonality of ILI in both temperate and tropical regions. Alternatively, the mechanism of action of AH on disease transmission may be different in cold-dry versus hot-humid settings

Study on biomethane production and biodegradability of different leafy vegetables in anaerobic digestion.

Science.gov (United States)

Yan, Hu; Zhao, Chen; Zhang, Jiafu; Zhang, Ruihong; Xue, Chunyu; Liu, Guangqing; Chen, Chang

2017-12-01

Enormous amounts of vegetable residues are wasted annually, causing many environmental problems due to their high moisture and organic contents. In this study, the methane production potential of 20 kinds of typical leafy vegetable residues in China were explored using a unified method. A connection between the biochemical components and the methane yields of these vegetables was well established which could be used to predict biogas performance in practice. A high volatile solid/total solid (VS/TS) ratio and hemicellulose content exhibited a positive impact on the biogas yield while lignin had a negative impact. In addition, three kinetic models were used to describe the methane production process of these agro-wastes. The systematic comparison of the methane production potentials of these leafy vegetables shown in this study will not only serve as a reference for basic research on anaerobic digestion but also provide useful data and information for agro-industrial applications of vegetable residues in future work.

Biomass production and composition of temperate and tropical maize in central Iowa

Science.gov (United States)

Bioethanol production in the Midwestern U.S. has largely focused on corn (Zea mays L.) grain for starch-based ethanol production. There has been growing interest in lignocellulosic biomass as a feedstock for biofuels. Because corn adapted to the tropics does not initiate senescence as early as ada...

Using Extreme Tropical Precipitation Statistics to Constrain Future Climate States

Science.gov (United States)

Igel, M.; Biello, J. A.

2017-12-01

Tropical precipitation is characterized by a rapid growth in mean intensity as the column humidity increases. This behavior is examined in both a cloud resolving model and with high-resolution observations of precipitation and column humidity from CloudSat and AIRS, respectively. The model and the observations exhibit remarkable consistency and suggest a new paradigm for extreme precipitation. We show that the total precipitation can be decomposed into a product of contributions from a mean intensity, a probability of precipitation, and a global PDF of column humidity values. We use the modeling and observational results to suggest simple, analytic forms for each of these functions. The analytic representations are then used to construct a simple expression for the global accumulated precipitation as a function of the parameters of each of the component functions. As the climate warms, extreme precipitation intensity and global precipitation are expected to increase, though at different rates. When these predictions are incorporated into the new analytic expression for total precipitation, predictions for changes due to global warming to the probability of precipitation and the PDF of column humidity can be made. We show that strong constraints can be imposed on the future shape of the PDF of column humidity but that only weak constraints can be set on the probability of precipitation. These are largely imposed by the intensification of extreme precipitation. This result suggests that understanding precisely how extreme precipitation responds to climate warming is critical to predicting other impactful properties of global hydrology. The new framework can also be used to confirm and discount existing theories for shifting precipitation.

An Analysis of the U.S. Wood Products Import Sector: Prospects for Tropical Wood Products Exporters

Directory of Open Access Journals (Sweden)

W.A.R.T.W. Bandara

2012-10-01

Full Text Available The U.S. has dramatically altered its wood product imports and exports during the past few years,and at present, it is the second largest wood product importer in the world. Hence, an understanding ofmarket structures, factors in selecting foreign suppliers, and the emphasis placed on environmentalissues/certification are critical to understand from the perspective of wood products importers in the U.S.This study provides an analysis of the U.S. wood products import sector with special emphasis on currentand future opportunities for tropical wood products exporters to the U.S. market.In this study, 158 wood products importers in the U.S. were surveyed using a mailingquestionnaire. The adjusted response rate was 40.6 percent. Results indicated that most of the respondentswere small to medium scale firms, but major importers of wood products. According to respondents,wood products to the U.S. mainly come from Brazil, Chile, and China. From the importers’ perspective,Brazilian wood products ranked first for its quality followed by wood products from Chile and Finland.Product quality, long term customer relationships, on-time delivery of orders, fair prices, and supplierreputation were the factors deemed important in selecting overseas suppliers. Majority of respondentswere importing certified wood products. FSC, SFI, and ISO 14000 were the mostly accepted certificationprograms. However, certification was not a major factor in foreign supplier selection criteria. Whenconsidered the U.S. wood products importers’ tendency to diversify their products and species imported,attractive opportunities exist for wood products suppliers from tropical countries.

Tropical convection regimes in climate models: evaluation with satellite observations

Directory of Open Access Journals (Sweden)

A. K. Steiner

2018-04-01

Full Text Available High-quality observations are powerful tools for the evaluation of climate models towards improvement and reduction of uncertainty. Particularly at low latitudes, the most uncertain aspect lies in the representation of moist convection and interaction with dynamics, where rising motion is tied to deep convection and sinking motion to dry regimes. Since humidity is closely coupled with temperature feedbacks in the tropical troposphere, a proper representation of this region is essential. Here we demonstrate the evaluation of atmospheric climate models with satellite-based observations from Global Positioning System (GPS radio occultation (RO, which feature high vertical resolution and accuracy in the troposphere to lower stratosphere. We focus on the representation of the vertical atmospheric structure in tropical convection regimes, defined by high updraft velocity over warm surfaces, and investigate atmospheric temperature and humidity profiles. Results reveal that some models do not fully capture convection regions, particularly over land, and only partly represent strong vertical wind classes. Models show large biases in tropical mean temperature of more than 4 K in the tropopause region and the lower stratosphere. Reasonable agreement with observations is given in mean specific humidity in the lower to mid-troposphere. In moist convection regions, models tend to underestimate moisture by 10 to 40 % over oceans, whereas in dry downdraft regions they overestimate moisture by 100 %. Our findings provide evidence that RO observations are a unique source of information, with a range of further atmospheric variables to be exploited, for the evaluation and advancement of next-generation climate models.

Tropical convection regimes in climate models: evaluation with satellite observations

Science.gov (United States)

Steiner, Andrea K.; Lackner, Bettina C.; Ringer, Mark A.

2018-04-01

High-quality observations are powerful tools for the evaluation of climate models towards improvement and reduction of uncertainty. Particularly at low latitudes, the most uncertain aspect lies in the representation of moist convection and interaction with dynamics, where rising motion is tied to deep convection and sinking motion to dry regimes. Since humidity is closely coupled with temperature feedbacks in the tropical troposphere, a proper representation of this region is essential. Here we demonstrate the evaluation of atmospheric climate models with satellite-based observations from Global Positioning System (GPS) radio occultation (RO), which feature high vertical resolution and accuracy in the troposphere to lower stratosphere. We focus on the representation of the vertical atmospheric structure in tropical convection regimes, defined by high updraft velocity over warm surfaces, and investigate atmospheric temperature and humidity profiles. Results reveal that some models do not fully capture convection regions, particularly over land, and only partly represent strong vertical wind classes. Models show large biases in tropical mean temperature of more than 4 K in the tropopause region and the lower stratosphere. Reasonable agreement with observations is given in mean specific humidity in the lower to mid-troposphere. In moist convection regions, models tend to underestimate moisture by 10 to 40 % over oceans, whereas in dry downdraft regions they overestimate moisture by 100 %. Our findings provide evidence that RO observations are a unique source of information, with a range of further atmospheric variables to be exploited, for the evaluation and advancement of next-generation climate models.

Determination of lipid oxidation products in vegetable oils and marine omega-3 supplements.

Science.gov (United States)

Halvorsen, Bente Lise; Blomhoff, Rune

2011-01-01

There is convincing evidence that replacing dietary saturated fats with polyunsaturated fats (PUFA) decreases risk of cardiovascular diseases. Therefore, PUFA rich foods such as vegetable oils, fatty fish, and marine omega-3 supplements are recommended. However, PUFA are easily oxidizable and there is concern about possible negative health effects from intake of oxidized lipids. Little is known about the degree of lipid oxidation in such products. To assess the content of lipid oxidation products in a large selection of vegetable oils and marine omega-3 supplements available in Norway. Both fresh and heated vegetable oils were studied. A large selection of commercially available vegetable oils and marine omega-3 supplements was purchased from grocery stores, pharmacies, and health food stores in Norway. The content of lipid oxidation products were measured as peroxide value and alkenal concentration. Twelve different vegetable oils were heated for a temperature (225°C) and time (25 minutes) resembling conditions typically used during cooking. The peroxide values were in the range 1.04-10.38 meq/kg for omega-3 supplements and in the range 0.60-5.33 meq/kg for fresh vegetable oils. The concentration range of alkenals was 158.23-932.19 nmol/mL for omega-3 supplements and 33.24-119.04 nmol/mL for vegetable oils. After heating, a 2.9-11.2 fold increase in alkenal concentration was observed for vegetable oils. The contents of hydroperoxides and alkenals in omega-3 supplements are higher than in vegetable oils. After heating vegetable oils, a large increase in alkenal concentration was observed.

Developing a water and nitrogen management model for greenhouse vegetable production in China

NARCIS (Netherlands)

Liang, Hao; Hu, Kelin; Batchelor, William D.; Qin, Wei; Li, Baoguo

2018-01-01

Excessive water and fertilizer inputs have led to a series of environmental problems in vegetable production areas in China. Identifying the fates of water and nutrients is crucial to develop best management strategies in intensive vegetable production systems. The objectives of this study were to

Influence of cover crop treatments on the performance of a vineyard in a humid region

Energy Technology Data Exchange (ETDEWEB)

Trigo-Córdoba, E.; Bouzas-Cid, Y.; Orriols-Fernández, I.; Díaz-Losada, E.; Mirás-Avalos, J.M.

2015-07-01

Vineyards are usually managed by tilling the inter-rows to avoid competition from other plants for soil water and nutrients. However, in humid and sub-humid climates, such as that of NW Spain, cover crops may be an advantage for controlling vine vegetative growth and improving berry composition, while reducing management costs. The current study was conducted over three consecutive growing seasons (2012-2014) to assess the effects of establishing three permanent cover crop treatments on water relations, vine physiology, yield and berry composition of a vineyard of the red cultivar ‘Mencía’ (Vitis vinifera L.) located in Leiro, Ourense. Treatments consisted of four different soil management systems: ST, soil tillage; NV, native vegetation; ER, English ryegrass (Lolium perenne L.); and SC, subterranean clover (Trifolium subterraneum L.). Midday stem water potential was more negative in the native vegetation treatment, causing significant reductions in leaf stomatal conductance on certain dates. Total vine leaf area and pruning weight was reduced in the cover crop treatments in the last year of the experiment. Yield was unaffected by the presence of a cover crop. No significant differences among treatments were observed for berry composition; however, wines were positively affected by the SC treatment (higher tannin content and colour intensity and lower malic acid concentration when compared with ST). Wines from the cover crop treatments were preferred by taste panelists. These results indicate that in humid climates cover crop treatments can be useful for reducing vine vegetative growth without compromising yield and berry quality. (Author)

Heavy metals in intensive greenhouse vegetable production systems along Yellow Sea of China

DEFF Research Database (Denmark)

Hu, Wenyou; Huang, Biao; Tian, Kang

2017-01-01

Recently, greenhouse vegetable production (GVP) has grown rapidly and counts a large proportion of vegetable production in China. In this study, the accumulation, health risk and threshold values of selected heavy metals were evaluated systematically. A total of 120 paired soil and vegetable...... relatively high concentrations and transfer factors of heavy metals. The accumulation of heavy metals in soils was affected by soil pH and soil organic matter. The calculated hazard quotients (HQ) of the heavy metals by vegetable consumption decreased in the order of leafy > rootstalk > fruit vegetables...... with hazard index (HI) values of 0.61, 0.33 and 0.26, respectively. The HI values were all below 1, which indicates that there is a low risk of greenhouse vegetable consumption. Soil threshold values (STVs) of heavy metals in GVP system were established according to the health risk assessment. The relatively...

Improving technology universal vegetable semi-finished products for the enterprises of food industry

Directory of Open Access Journals (Sweden)

M. N. Kutkina

2016-01-01

Full Text Available Healthy nutrition is one of the main factors that becomes stronger the human immune system, especially in the big cities, forms intellectual abilities of people, increases the qualitative characteristics of living standards etc. The most important components of a healthy nutrition are vegetables and products from them. Rather high moisture content of many vegetables, e.g., fruit, partially fills the needs of the human organism in water, lowers the energy value of the diet, enhances the motility of the gastrointestinal tract. In this regard, the improvement of technology universal product from regional vegetables available has got importance, prolonged pronounced social effect and contributes to health improvement. Among vegetables the zucchini include diet properties, but the use of them is accompanied by certain difficulties associated with seasonal logistics and the limited range of products from them. In this work, there were studied the varietal characteristics of the zucchini, zoned in the North-West region, in terms of their technological properties, morphological characteristics and biochemical composition of fruit during ripening. Were investigated the optimal ways of canning zucchini by drying with freeze-drying and infrared heating that allows you to provide catering universal semi-finished product during the whole year, not only in areas of cultivation, but also in areas outside of growing vegetables. There was discovered the effect of anomalous dehydration of fruit vegetables in the result of the study , which helped to explain the increased, in comparison with other types of vegetables, losses during heat treatment and to justify their methods and technological parameters of drying. It was found that one of the reasons for the reduction of mechanical strength parenchymal tissue of fruit vegetables, is the destruction of cell walls by increasing the pressure inside the air inclusions, in contrast to some other types of fruit

Improved Estimates of Clear Sky Longwave Flux and Application to the Tropical Greenhouse Effect

Science.gov (United States)

Collins, W. D.

1997-01-01

The first objective of this investigation is to eliminate the clear-sky offset introduced by the scene-identification procedures developed for the Earth Radiation Budget Experiment (ERBE). Estimates of this systematic bias range from 10 to as high as 30 W/sq m. The initial version of the ScaRaB data is being processed with the original ERBE algorithm. Since the ERBE procedure for scene identification is based upon zonal flux averages, clear scenes with longwave emission well below the zonal mean value are mistakenly classified as cloudy. The erroneous classification is more frequent in regions with deep convection and enhanced mid- and upper-tropospheric humidity. We will develop scene identification parameters with zonal and/or time dependence to reduce or eliminate the bias in the clear- sky data. The modified scene identification procedure could be used for the ScaRaB-specific version of the Earth-radiation products. The second objective is to investigate changes in the clear-sky Outgoing Longwave Radiation (OLR) associated with decadal variations in the tropical and subtropical climate. There is considerable evidence for a shift in the climate state starting in approximately 1977. The shift is accompanied by higher SSTs in the equatorial Pacific, increased tropical convection, and higher values of atmospheric humidity. Other evidence indicates that the humidity in the tropical troposphere has been steadily increasing over the last 30 years. It is not known whether the atmospheric greenhouse effect has increased during this period in response to these changes in SST and precipitable water. We will investigate the decadal-scale fluctuations in the greenhouse effect using Nimbus-7, ERBE, and ScaRaB measurements spaning 1979 to the present. The data from the different satellites will be intercalibrated by comparison with model calculations based upon ship radiosonde observations. The fluxes calculated from the radiation model will also be used for validation of the

Evaluation of the New Dynamic Global Vegetation Model in CAS-ESM

Science.gov (United States)

Zhu, Jiawen; Zeng, Xiaodong; Zhang, Minghua; Dai, Yongjiu; Ji, Duoying; Li, Fang; Zhang, Qian; Zhang, He; Song, Xiang

2018-06-01

In the past several decades, dynamic global vegetation models (DGVMs) have been the most widely used and appropriate tool at the global scale to investigate vegetation-climate interactions. At the Institute of Atmospheric Physics, a new version of DGVM (IAP-DGVM) has been developed and coupled to the Common Land Model (CoLM) within the framework of the Chinese Academy of Sciences' Earth System Model (CAS-ESM). This work reports the performance of IAP-DGVM through comparisons with that of the default DGVM of CoLM (CoLM-DGVM) and observations. With respect to CoLMDGVM, IAP-DGVM simulated fewer tropical trees, more "needleleaf evergreen boreal tree" and "broadleaf deciduous boreal shrub", and a better representation of grasses. These contributed to a more realistic vegetation distribution in IAP-DGVM, including spatial patterns, total areas, and compositions. Moreover, IAP-DGVM also produced more accurate carbon fluxes than CoLM-DGVM when compared with observational estimates. Gross primary productivity and net primary production in IAP-DGVM were in better agreement with observations than those of CoLM-DGVM, and the tropical pattern of fire carbon emissions in IAP-DGVM was much more consistent with the observation than that in CoLM-DGVM. The leaf area index simulated by IAP-DGVM was closer to the observation than that of CoLM-DGVM; however, both simulated values about twice as large as in the observation. This evaluation provides valuable information for the application of CAS-ESM, as well as for other model communities in terms of a comparative benchmark.

Changes in the Diversity of Soil Arbuscular Mycorrhizal Fungi after Cultivation for Biofuel Production in a Guantanamo (Cuba) Tropical System

Science.gov (United States)

Alguacil, Maria del Mar; Torrecillas, Emma; Hernández, Guillermina; Roldán, Antonio

2012-01-01

The arbuscular mycorrhizal fungi (AMF) are a key, integral component of the stability, sustainability and functioning of ecosystems. In this study, we characterised the AMF biodiversity in a native vegetation soil and in a soil cultivated with Jatropha curcas or Ricinus communis, in a tropical system in Guantanamo (Cuba), in order to verify if a change of land use to biofuel plant production had any effect on the AMF communities. We also asses whether some soil properties related with the soil fertility (total N, Organic C, microbial biomass C, aggregate stability percentage, pH and electrical conductivity) were changed with the cultivation of both crop species. The AM fungal small sub-unit (SSU) rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Twenty AM fungal sequence types were identified: 19 belong to the Glomeraceae and one to the Paraglomeraceae. Two AMF sequence types related to cultured AMF species (Glo G3 for Glomus sinuosum and Glo G6 for Glomus intraradices-G. fasciculatum-G. irregulare) did not occur in the soil cultivated with J. curcas and R. communis. The soil properties (total N, Organic C and microbial biomass C) were higher in the soil cultivated with the two plant species. The diversity of the AMF community decreased in the soil of both crops, with respect to the native vegetation soil, and varied significantly depending on the crop species planted. Thus, R. communis soil showed higher AMF diversity than J. curcas soil. In conclusion, R. communis could be more suitable for the long-term conservation and sustainable management of these tropical ecosytems. PMID:22536339

Changes in the diversity of soil arbuscular mycorrhizal fungi after cultivation for biofuel production in a Guantanamo (Cuba tropical system.

Directory of Open Access Journals (Sweden)

Maria del Mar Alguacil

Full Text Available The arbuscular mycorrhizal fungi (AMF are a key, integral component of the stability, sustainability and functioning of ecosystems. In this study, we characterised the AMF biodiversity in a native vegetation soil and in a soil cultivated with Jatropha curcas or Ricinus communis, in a tropical system in Guantanamo (Cuba, in order to verify if a change of land use to biofuel plant production had any effect on the AMF communities. We also asses whether some soil properties related with the soil fertility (total N, Organic C, microbial biomass C, aggregate stability percentage, pH and electrical conductivity were changed with the cultivation of both crop species. The AM fungal small sub-unit (SSU rRNA genes were subjected to PCR, cloning, sequencing and phylogenetic analyses. Twenty AM fungal sequence types were identified: 19 belong to the Glomeraceae and one to the Paraglomeraceae. Two AMF sequence types related to cultured AMF species (Glo G3 for Glomus sinuosum and Glo G6 for Glomus intraradices-G. fasciculatum-G. irregulare did not occur in the soil cultivated with J. curcas and R. communis. The soil properties (total N, Organic C and microbial biomass C were higher in the soil cultivated with the two plant species. The diversity of the AMF community decreased in the soil of both crops, with respect to the native vegetation soil, and varied significantly depending on the crop species planted. Thus, R. communis soil showed higher AMF diversity than J. curcas soil. In conclusion, R. communis could be more suitable for the long-term conservation and sustainable management of these tropical ecosytems.

Primary production in a tropical large lake: The role of phytoplankton composition

International Nuclear Information System (INIS)

Darchambeau, F.; Sarmento, H.; Descy, J.-P.

2014-01-01

Phytoplankton biomass and primary production in tropical large lakes vary at different time scales, from seasons to centuries. We provide a dataset made of 7 consecutive years of phytoplankton biomass and production in Lake Kivu (Eastern Africa). From 2002 to 2008, bi-weekly samplings were performed in a pelagic site in order to quantify phytoplankton composition and biomass, using marker pigments determined by HPLC. Primary production rates were estimated by 96 in situ 14 C incubations. A principal component analysis showed that the main environmental gradient was linked to a seasonal variation of the phytoplankton assemblage, with a clear separation between diatoms during the dry season and cyanobacteria during the rainy season. A rather wide range of the maximum specific photosynthetic rate (P Bm ) was found, ranging between 1.15 and 7.21 g carbon g −1 chlorophyll a h −1 , and was best predicted by a regression model using phytoplankton composition as an explanatory variable. The irradiance at the onset of light saturation (I k ) ranged between 91 and 752 μE m −2 s −1 and was linearly correlated with the mean irradiance in the mixed layer. The inter-annual variability of phytoplankton biomass and production was high, ranging from 53 to 100 mg chlorophyll a m −2 (annual mean) and from 143 to 278 g carbon m −2 y −1 , respectively. The degree of seasonal mixing determined annual production, demonstrating the sensitivity of tropical lakes to climate variability. A review of primary production of other African great lakes allows situating Lake Kivu productivity in the same range as that of lakes Tanganyika and Malawi, even if mean phytoplankton biomass was higher in Lake Kivu. - Highlights: • We provide a 7-year dataset of primary production in a tropical great lake. • Specific photosynthetic rate was determined by community composition. • Annual primary production varied between 143 and 278 mg C m −2 y −1 . • Pelagic production was highly

prevalence of bovine fasciolosis in major abattiors of adamawa state

African Journals Online (AJOL)

DR. AMINU

the metacercariae during grazing on vegetation. Tropical ... January-March when relative humidity drops to 13%. Mubi ... at Yola abattoir; ten (10) animals were examined in. Mubi, while ..... Soulsby, E. J. W. (1982): Helminths, Arthropods and.

Rubisco activity and gene expression of tropical tree species under ...

African Journals Online (AJOL)

Tropical rain forests contain an ecologically and physiologically diverse range of vegetation and habitats. Sun-acclimated plants can be divided into two groups, shade-tolerant and shade-intolerant, according to the plant's physiological and genetic responses. Some tropical species have potential capacity for light damage ...

Humidity measurements in the precast concrete

International Nuclear Information System (INIS)

Hurez, M.

1986-01-01

The precast concrete industry manufactures requires a good knowledge and control of the humidity factor: during the manufacturing process, in order to regulate the water content of aggregates, or the fresh concrete workability: during the quality control of the product characteristics. The principles of measurements: conductivity, dielectric characteristics and neutron moisture meters are compared for cost, humidity range, accuracy, temperature dependence, interfering elements, density dependence, grain size and shape [fr

Determination of lipid oxidation products in vegetable oils and marine omega-3 supplements

Directory of Open Access Journals (Sweden)

Rune Blomhoff

2011-06-01

Full Text Available Background : There is convincing evidence that replacing dietary saturated fats with polyunsaturated fats (PUFA decreases risk of cardiovascular diseases. Therefore, PUFA rich foods such as vegetable oils, fatty fish, and marine omega-3 supplements are recommended. However, PUFA are easily oxidizable and there is concern about possible negative health effects from intake of oxidized lipids. Little is known about the degree of lipid oxidation in such products. Objective : To assess the content of lipid oxidation products in a large selection of vegetable oils and marine omega-3 supplements available in Norway. Both fresh and heated vegetable oils were studied. Design : A large selection of commercially available vegetable oils and marine omega-3 supplements was purchased from grocery stores, pharmacies, and health food stores in Norway. The content of lipid oxidation products were measured as peroxide value and alkenal concentration. Twelve different vegetable oils were heated for a temperature (225°C and time (25 minutes resembling conditions typically used during cooking. Results : The peroxide values were in the range 1.04–10.38 meq/kg for omega-3 supplements and in the range 0.60–5.33 meq/kg for fresh vegetable oils. The concentration range of alkenals was 158.23–932.19 nmol/mL for omega-3 supplements and 33.24–119.04 nmol/mL for vegetable oils. After heating, a 2.9–11.2 fold increase in alkenal concentration was observed for vegetable oils. Conclusions : The contents of hydroperoxides and alkenals in omega-3 supplements are higher than in vegetable oils. After heating vegetable oils, a large increase in alkenal concentration was observed.

Health risk assessment of heavy metals in vegetables grown around battery production area

Directory of Open Access Journals (Sweden)

Ying Chen

2014-04-01

Full Text Available Battery production is one of the main sources of heavy metals that present great harm to human health even in low concentrations. Chromium (Cr, Cadmium (Cd and Lead (Pb were measured in edible portions of vegetables and soils around a battery production area in China, and the potential health risk of heavy metal contamination to the local population via vegetable consumption was evaluated. Their concentrations in edible portions of vegetables were 2.354 (0.078-14.878, 0.035 (0.003-0.230 and 0.039 (0.003-0.178 mg kg-1, respectively. Approximately 3 % of the Cd in the vegetable samples exceeded the maximum concentration allowable by national food safety criteria, although Pb content in all samples were within the criteria. Transfer factors (TF from soils to vegetables were dependent on vegetable species. Leguminous vegetables were more likely to accumulate Cr, while leaf vegetables tended to show higher levels of concentration of Cd and Pb. Melon vegetables demonstrated a relatively low capacity for accumulating the heavy metals studied. TF were positively correlated with soil organic matter and negatively correlated with soil pH. The mean estimated daily intake of Cr, Cd and Pb via dietary consumption of vegetables was 0.011, 1.65 × 10-4 and 1.84 × 10-4 mg kg-1 of body weight per day, respectively, levels that were much lower than the reference doses recommended by USEPA (U.S. Environmental Protection Agency and JECFA (Joint FAO/WHO Expert Committee on Food Additives, indicating that the potential health risk of Cr, Cd and Pb exposure via vegetable consumption to the local population around this battery production area could be negligible.

Surface energy exchanges over contrasting vegetation types on a subtropical sand island

Science.gov (United States)

Gray, Michael; McGowan, Hamish; Lowry, Andrew; Guyot, Adrien

2017-04-01

The surface energy balance of subtropical coastal vegetation communities has thus far received little attention. Here we present a multi-year observational data set using the eddy covariance method to quantify for the first time the surface energy balance over three contrasting vegetation types on a subtropical sand island in eastern Australia: a periodically inundated sedge swamp, an exotic pine plantation and a coastal heath. Maximum daily sensible heat flux varied between sites but was typically > 280 Wm-2 in the coastal heath and pine plantation but no more than 250 Wm-2 in the swamp when dry and 1. The partitioning of energy, as represented by β, is similar to a variety of Australian ecosystems, and a range of coastal vegetation types in other latitudes, but differs from other tropical or subtropical locations which have strongly seasonal rainfall patterns and therefore a switch from β > 1 before rainfall to β changes in background meteorology with the most important influences being net radiation, absolute humidity, and rainfall. The main factor differentiating the sites was soil water content, with the remnant coastal heath and swamp having ready access to water but the exotic pine plantation having much drier soils. Should the current balance between remnant vegetation and the pine plantation undergo changes there would be a corresponding shift in the surface energy balance of the island as a whole, and altered plant water use may lead to reduced water table depth, important because the groundwater of the local islands is used as part of a regional water grid. A better understanding of the response of coastal vegetation to atmospheric forcing will enable more informed decision making on land use changes, as coastal regions the world over face development pressure.

Radiation absorption and use by humid savanna grassland: assessment using remote sensing and modelling

International Nuclear Information System (INIS)

Roux, X. le; Gauthier, H.; Begue, A.; Sinoquet, H.

1997-01-01

The components of the canopy radiation balance in photosynthetically active radiation (PAR), phytomass and leaf area index (LAI) were measured during a complete annual cycle in an annually burned African humid savanna. Directional reflectances measured by a hand-held radiometer were used to compute the canopy normalized difference vegetation index (NDVI). The fraction f APAR of PAR absorbed by the canopy (APAR) and canopy reflectances were simulated by the scattering from arbitrarily inclined leaves (SAIL) and the radiation interception in row intercropping (RIRI) models. The daily PAR to solar radiation ratio was linearly related to the daily fraction of diffuse solar radiation with an annual value around 0.47. The observed f APAR was non-linearly related to NDVI. The SAIL model simulated reasonably well directional reflectances but noticeably overestimated f APAR during most of the growing season. Comparison of simulations performed with the 1D and 3D versions of the RIRI model highlighted the weak influence of the heterogeneous structure of the canopy after fire and of the vertical distribution of dead and green leaves on total f APAR . Daily f APAR values simulated by the 3D-RIRI model were linearly related to and 9.8% higher than observed values. For sufficient soil water availability, the net production efficiency ϵ n of the savanna grass canopy was 1.92 and 1.28 g DM MJ −1 APAR (where DM stands for dry matter) during early regrowth and mature stage, respectively. In conclusion, the linear relationship between NDVI and f APAR used in most primary production models operating at large scales may slightly overestimate f APAR by green leaves for the humid savanna biome. Moreover, the net production efficiency of humid savannas is close to or higher than values reported for the other major natural biomes. (author)

Characterizing the Suitability of Selected Indigenous Soil Improving Legumes in a Humid Tropical Environment Using Shoot and Root Attributes

Directory of Open Access Journals (Sweden)

Anikwe, MAN.

2003-01-01

Full Text Available We studied the biomass accumulation, root length, nodulation, and chemical composition of roots and shoot of ten indigenous soil improving legumes in a humid tropical ecosystem with the view to selecting species for soil improvement programmes. Two cultivars of Vigna unguiculata, and one each of Glycine max, Arachis hypogaea, Crotararia ochroleuca, Cajanus cajan, Pueraria phaseoloides, Lablab purpureus, Mucuna pruriens and Vigna subterranea as treatments were planted in 20 kg pots containing soil from an Oxic paleustalf in Nigeria. The pots were arranged in randomized complete block layout with three replications in a greenhouse at IITA Ibadan, Nigeria. Results from the work show that M. pruriens and C. cajan produced the highest quantity of biomass. Root elongation was highest in M. pruriens whereas A. hypogaea produced the most root nodules with native rhizobia. The highest quantity of nodule dry weight was produced by A. hypogaea and P. phaseoloides whereas most of the legumes except G. max and P. phaseoloides had high and statistically comparable N content of between 2.36 and 3.34 mg.kg-1 N. The results show that the legumes have different root and shoot characteristics, which should be taken into consideration when selecting species for soil improvement programmes.

Detecting leaf phenology of seasonally moist tropical forests in South America with multi-temporal MODIS images.

Science.gov (United States)

Xiangming Xiao; Stephen Hagen; Qingyuan Zhang; Michael Keller; Berrien Moore III

2006-01-01

Leaf phenology of tropical evergreen forests affects carbon and water fluxes. In an earlier study of a seasonally moist evergreen tropical forest site in the Amazon basin, time series data of Enhanced Vegetation Index (EVI) from the VEGETATION and Moderate Resolution Imaging Spectroradiometer (MODIS) sensors showed an unexpected seasonal pattern, with higher EVI in the...

An analysis on vegetation pattern of ecotone in North China

Energy Technology Data Exchange (ETDEWEB)

Jia, J.C.; Zhang, H.Y. [North China Electric Power Univ., Beijing (China). Energy and Environmental Research Center

2008-07-01

Vegetation pattern is influenced by several natural factors, including climatic elements, elevation factors and soil conditions. Since soil formation and soil types are influenced by water-temperature conditions, much can be learned about vegetation distribution patterns by studying the relationship between water-temperature conditions and vegetation distribution. This paper presented the results of a study whose purpose was to provide scientific evidence for exploiting natural resources, planting trees, and restoring grassland from cropland. A warmth index (WI ) and humidity index (HI) were used to examine the relation between the distribution of vegetation and the water-temperature condition in North China's ecotone, the transition area between two adjacent but different plant communities, including steppe, bush and forest ecosystems. A vegetation map of the study site was digitized and then converted into a vegetation grid map from which 17 different vegetation types were chosen as the study object. A monthly mean temperature grid map and precipitation grid map of the study site were made based on the method of spatial interpolation, by using 119 meteorological data for 50 years during the period from 1951 to 2000. The thermal distribution curves and humidity distribution curves of 17 vegetation types in North China, determined the whole range and optimum range of WI and HI of 17 vegetation types. The relative proportion of each vegetation type distributed in the optimum range of WI and HI were calculated. The vegetation pattern was analyzed according to the WI and HI standard, and was described by species and their relative amount. 10 refs., 5 tabs., 3 figs.

Vegetable fats and oils as functional ingredients in meat products

Directory of Open Access Journals (Sweden)

Alfonso Totosaus

2011-12-01

Full Text Available Sausages are a widely consumed food in México, and due to their low fat content (ca. 10% they can be employed to enrich diet by including functional or nutraceutic ingredients as vegetable fats and oils. The replace or incorporation of vegetable fats or oils in cooked sausages is a way to improve their nutritional profile to offer functional meat products.

Spectral entropy as a mean to quantify water stress history for natural vegetation and irrigated agriculture in a water-stressed tropical environment

Science.gov (United States)

Kim, Y.; Johnson, M. S.

2017-12-01

Spectral entropy (Hs) is an index which can be used to measure the structural complexity of time series data. When a time series is made up of one periodic function, the Hs value becomes smaller, while Hs becomes larger when a time series is composed of several periodic functions. We hypothesized that this characteristic of the Hs could be used to quantify the water stress history of vegetation. For the ideal condition for which sufficient water is supplied to an agricultural crop or natural vegetation, there should be a single distinct phenological cycle represented in a vegetation index time series (e.g., NDVI and EVI). However, time series data for a vegetation area that repeatedly experiences water stress may include several fluctuations that can be observed in addition to the predominant phenological cycle. This is because the process of experiencing water stress and recovering from it generates small fluctuations in phenological characteristics. Consequently, the value of Hs increases when vegetation experiences several water shortages. Therefore, the Hs could be used as an indicator for water stress history. To test this hypothesis, we analyzed Moderate Resolution Imaging Spectroradiometer (MODIS) Normalized Difference Vegetation Index (NDVI) data for a natural area in comparison to a nearby sugarcane area in seasonally-dry western Costa Rica. In this presentation we will illustrate the use of spectral entropy to evaluate the vegetative responses of natural vegetation (dry tropical forest) and sugarcane under three different irrigation techniques (center pivot irrigation, drip irrigation and flood irrigation). Through this comparative analysis, the utility of Hs as an indicator will be tested. Furthermore, crop response to the different irrigation methods will be discussed in terms of Hs, NDVI and yield.

Diurnal sampling reveals significant variation in CO2 emission from a tropical productive lake.

Science.gov (United States)

Reis, P C J; Barbosa, F A R

2014-08-01

It is well accepted in the literature that lakes are generally net heterotrophic and supersaturated with CO2 because they receive allochthonous carbon inputs. However, autotrophy and CO2 undersaturation may happen for at least part of the time, especially in productive lakes. Since diurnal scale is particularly important to tropical lakes dynamics, we evaluated diurnal changes in pCO2 and CO2 flux across the air-water interface in a tropical productive lake in southeastern Brazil (Lake Carioca) over two consecutive days. Both pCO2 and CO2 flux were significantly different between day (9:00 to 17:00) and night (21:00 to 5:00) confirming the importance of this scale for CO2 dynamics in tropical lakes. Net heterotrophy and CO2 outgassing from the lake were registered only at night, while significant CO2 emission did not happen during the day. Dissolved oxygen concentration and temperature trends over the diurnal cycle indicated the dependence of CO2 dynamics on lake metabolism (respiration and photosynthesis). This study indicates the importance of considering the diurnal scale when examining CO2 emissions from tropical lakes.

Perceptions of using low-quality irrigation water in vegetable production in Morogoro, Tanzania

DEFF Research Database (Denmark)

Mayilla, Winfrida; Keraita, Bernard; Ngowi, Helena

2017-01-01

This study was conducted to examine perceptions of the farmers and key informants on the use of low-quality irrigation water for vegetable production in urban and peri-urban areas in Morogoro, Tanzania. The methods used to collect data were farmer surveys (n = 60), focus group discussions (n = 4)...... in formulating policies and creating health promotion awareness for safe use of low-quality water for benefit maximization and health risk reduction....... of buying commercial fertilizers, vegetable production all year round, sustainable income generation from selling vegetables and also jobs creation in the community among farmers and vegetable sellers. Findings from Mann–Whitney U test and Kruskal–Wallis test score on farmers perception scales indicate...

The transgenosis main directions in vegetable and melon production: theory and practice

Directory of Open Access Journals (Sweden)

Н. В. Лещук

2013-08-01

Full Text Available The article deals with priority directions of vegetable and melon plants selection. The wide varieties of alien genetic information transferring methods during the transgenic plants creation of vegetable and melon species are grounded. The essence of the new hybrids identification method as genetic engineering products: kind of cabbage, tomatoes, carrots, zucchini, lettuce seed, pea Pisum sativum, common bean, eggplant and capsicum is revealed. The transgenosis main directions of botanical taxa varieties of vegetable and melon plants on condition of the international and national practice holding are proved. The international practice of the state approbation and registration of genetically engineered structures in biological objects (plant varieties and in their processed products are studied. A monitoring about food and pharmaceutical substances based on genetically modified varieties and hybrids structures of vegetable and melon plants have been held.

Causes of postpartum anoestrus in cattle in the tropics

International Nuclear Information System (INIS)

Hansel, W.; Alila, H.W.

1984-01-01

Prolonged postpartum anoestrus is a major cause of economic losses in cattle in most tropical countries. The length of the period from parturition to first oestrus varies greatly in cattle in the tropics and is influenced by many factors, including endocrine events, management, nutrition, heat and humidity, genetic-environmental interactions, diseases and internal and external parasites. Results of recent research on endocrinology of the postpartum cow are particularly relevant to the problem in tropical cattle. Development of a pulsatile pattern of pituitary luteinizing hormone (LH) secretion is necessary for induction of the first postpartum oestrus, and many cows undergo a short episode of elevated plasma progesterone levels immediately before the first oestrus. Adrenal corticosteroids inhibit development of the pulsatile pattern of LH secretion. The concept is developed that elevated levels of cortisol, resulting from the stresses of heat, high humidity, malnutrition, parasites and diseases to which tropical cattle are often exposed, contribute to anoestrus. Techniques developed for oestrous cycle synchronization of cyclic cattle have been found to induce first oestrus and a fertile ovulation in a significant percentage of anoestrous lactating beef cattle. These treatments involve short-term (6-7 day) progesterone treatments, followed by single injections of prostaglandin Fsub(2α) and insemination 80 hours later. Some success has also been achieved in shortening the postpartum interval by pulsatile administration of gonadotropin-releasing hormone which, in turn, causes pulsatile release of LH, and by administering progestational compounds for short periods of time. Improved management, particularly oestrus detection and insemination at the optimum time, could contribute greatly to reducing the postpartum interval in tropical cattle. Nutritional factors that result in reduced haemoglobin levels (trace mineral deficiencies and parasite infestations) also cause

SOLID BIOFUEL UTILIZATION IN VEGETABLE OIL PRODUCTION

Directory of Open Access Journals (Sweden)

Slusarenko V.

2016-08-01

Full Text Available The paper deals with questions of creating at JSC “Alimentarmash "in the last 20 years the technological equipment for the production of vegetable oils from oilseeds: from the press for the final spin to mini oilfactory, using as an energy source for heating the liquid coolant (Thermal oil "Arian" of solid biofuels - husk of sunflower seeds.

Reproductive phenology of coastal plain Atlantic forest vegetation: comparisons from seashore to foothills.

Science.gov (United States)

Staggemeier, Vanessa Graziele; Morellato, Leonor Patrícia Cerdeira

2011-11-01

The diversity of tropical forest plant phenology has called the attention of researchers for a long time. We continue investigating the factors that drive phenological diversity on a wide scale, but we are unaware of the variation of plant reproductive phenology at a fine spatial scale despite the high spatial variation in species composition and abundance in tropical rainforests. We addressed fine scale variability by investigating the reproductive phenology of three contiguous vegetations across the Atlantic rainforest coastal plain in Southeastern Brazil. We asked whether the vegetations differed in composition and abundance of species, the microenvironmental conditions and the reproductive phenology, and how their phenology is related to regional and local microenvironmental factors. The study was conducted from September 2007 to August 2009 at three contiguous sites: (1) seashore dominated by scrub vegetation, (2) intermediary covered by restinga forest and (3) foothills covered by restinga pre-montane transitional forest. We conducted the microenvironmental, plant and phenological survey within 30 transects of 25 m × 4 m (10 per site). We detected significant differences in floristic, microenvironment and reproductive phenology among the three vegetations. The microenvironment determines the spatial diversity observed in the structure and composition of the flora, which in turn determines the distinctive flowering and fruiting peaks of each vegetation (phenological diversity). There was an exchange of species providing flowers and fruits across the vegetation complex. We conclude that plant reproductive patterns as described in most phenological studies (without concern about the microenvironmental variation) may conceal the fine scale temporal phenological diversity of highly diverse tropical vegetation. This phenological diversity should be taken into account when generating sensor-derived phenologies and when trying to understand tropical vegetation

Late Pliocene diversity and distribution of Drynaria (Polypodiaceae in western Yunnan explained by forest vegetation and humid climates

Directory of Open Access Journals (Sweden)

Yong-Jiang Huang

2016-08-01

Full Text Available The palaeodiversity of flowering plants in Yunnan has been extensively interpreted from both a molecular and fossil perspective. However, for cryptogamic plants such as ferns, the palaeodiversity remains poorly known. In this study, we describe a new ferny fossil taxon, Drynaria lanpingensis sp. nov. Huang, Su et Zhou (Polypodiaceae, from the late Pliocene of northwestern Yunnan based on fragmentary frond and pinna with in situ spores. The frond is pinnatifid and the pinnae are entirely margined. The sori are arranged in one row on each side of the primary vein. The spores have a semicircular to bean-shaped equatorial view and a tuberculate surface. Taken together with previously described fossils, there are now representatives of three known fossil taxa of Drynaria from the late Pliocene of western Yunnan. These finds suggest that Drynaria diversity was considerable in the region at that time. As Drynaria is a shade-tolerant plant, growing preferably in wet conditions in the understory of forests, its extensive existence may indicate forest vegetation and humid climates in western Yunnan during the late Pliocene. This is in line with results from floristic investigations and palaeoclimatic reconstructions based on fossil floras.

Determination of tropical deforestation rates and related carbon losses from 1990 to 2010.

Science.gov (United States)

Achard, Frédéric; Beuchle, René; Mayaux, Philippe; Stibig, Hans-Jürgen; Bodart, Catherine; Brink, Andreas; Carboni, Silvia; Desclée, Baudouin; Donnay, François; Eva, Hugh D; Lupi, Andrea; Raši, Rastislav; Seliger, Roman; Simonetti, Dario

2014-08-01

We estimate changes in forest cover (deforestation and forest regrowth) in the tropics for the two last decades (1990-2000 and 2000-2010) based on a sample of 4000 units of 10 ×10 km size. Forest cover is interpreted from satellite imagery at 30 × 30 m resolution. Forest cover changes are then combined with pan-tropical biomass maps to estimate carbon losses. We show that there was a gross loss of tropical forests of 8.0 million ha yr(-1) in the 1990s and 7.6 million ha yr(-1) in the 2000s (0.49% annual rate), with no statistically significant difference. Humid forests account for 64% of the total forest cover in 2010 and 54% of the net forest loss during second study decade. Losses of forest cover and Other Wooded Land (OWL) cover result in estimates of carbon losses which are similar for 1990s and 2000s at 887 MtC yr(-1) (range: 646-1238) and 880 MtC yr(-1) (range: 602-1237) respectively, with humid regions contributing two-thirds. The estimates of forest area changes have small statistical standard errors due to large sample size. We also reduce uncertainties of previous estimates of carbon losses and removals. Our estimates of forest area change are significantly lower as compared to national survey data. We reconcile recent low estimates of carbon emissions from tropical deforestation for early 2000s and show that carbon loss rates did not change between the two last decades. Carbon losses from deforestation represent circa 10% of Carbon emissions from fossil fuel combustion and cement production during the last decade (2000-2010). Our estimates of annual removals of carbon from forest regrowth at 115 MtC yr(-1) (range: 61-168) and 97 MtC yr(-1) (53-141) for the 1990s and 2000s respectively are five to fifteen times lower than earlier published estimates. © The Authors Global Change Biology Published by John Wiley & Sons Ltd.

Clinker mineral hydration at reduced relative humidities

DEFF Research Database (Denmark)

Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Lachowski, Eric E.

1999-01-01

and experimental data are presented showing that C(3)A can hydrate at lower humidities than either C3S or C2S. It is suggested that the initiation of hydration during exposure to water vapour is nucleation controlled. When C(3)A hydrates at low humidity, the characteristic hydration product is C(3)AH(6......Vapour phase hydration of purl cement clinker minerals at reduced relative humidities is described. This is relevant to modern high performance concrete that may self-desiccate during hydration and is also relevant to the quality of the cement during storage. Both the oretical considerations...

Early warming of tropical South America at the last glacial-interglacial transition.

Science.gov (United States)

Seltzer, G O; Rodbell, D T; Baker, P A; Fritz, S C; Tapia, P M; Rowe, H D; Dunbar, R B

2002-05-31

Glaciation in the humid tropical Andes is a sensitive indicator of mean annual temperature. Here, we present sedimentological data from lakes beyond the glacial limit in the tropical Andes indicating that deglaciation from the Last Glacial Maximum led substantial warming at high northern latitudes. Deglaciation from glacial maximum positions at Lake Titicaca, Peru/Bolivia (16 degrees S), and Lake Junin, Peru (11 degrees S), occurred 22,000 to 19,500 calendar years before the present, several thousand years before the Bølling-Allerød warming of the Northern Hemisphere and deglaciation of the Sierra Nevada, United States (36.5 degrees to 38 degrees N). The tropical Andes deglaciated while climatic conditions remained regionally wet, which reflects the dominant control of mean annual temperature on tropical glaciation.

Culvert flow in small drainages in montane tropical forests: observations from the Luquillo Experimental Forest of Puerto Rico.

Science.gov (United States)

F. N. Scatena

1990-01-01

This paper describe the hydraulics of unsubmerged flow for 5 culverts in the Luiquillo Esperimental Forest of Puerto Rico. A General equation based on empirical data is presented to estimate culvert discharge during unsubmerged conditions. Large culverts are needed in humid tropical montane areas than in humid temperatute watersheds and are usually appropriate only...

Plant Traits Demonstrate That Temperate and Tropical Giant Eucalypt Forests Are Ecologically Convergent with Rainforest Not Savanna

Science.gov (United States)

Tng, David Y. P.; Jordan, Greg J.; Bowman, David M. J. S.

2013-01-01

Ecological theory differentiates rainforest and open vegetation in many regions as functionally divergent alternative stable states with transitional (ecotonal) vegetation between the two forming transient unstable states. This transitional vegetation is of considerable significance, not only as a test case for theories of vegetation dynamics, but also because this type of vegetation is of major economic importance, and is home to a suite of species of conservation significance, including the world’s tallest flowering plants. We therefore created predictions of patterns in plant functional traits that would test the alternative stable states model of these systems. We measured functional traits of 128 trees and shrubs across tropical and temperate rainforest – open vegetation transitions in Australia, with giant eucalypt forests situated between these vegetation types. We analysed a set of functional traits: leaf carbon isotopes, leaf area, leaf mass per area, leaf slenderness, wood density, maximum height and bark thickness, using univariate and multivariate methods. For most traits, giant eucalypt forest was similar to rainforest, while rainforest, particularly tropical rainforest, was significantly different from the open vegetation. In multivariate analyses, tropical and temperate rainforest diverged functionally, and both segregated from open vegetation. Furthermore, the giant eucalypt forests overlapped in function with their respective rainforests. The two types of giant eucalypt forests also exhibited greater overall functional similarity to each other than to any of the open vegetation types. We conclude that tropical and temperate giant eucalypt forests are ecologically and functionally convergent. The lack of clear functional differentiation from rainforest suggests that giant eucalypt forests are unstable states within the basin of attraction of rainforest. Our results have important implications for giant eucalypt forest management. PMID:24358359

Plant cover and hydrological response in a seasonally dry tropical forest (SDTF = Cobertura vegetal e as respostas hidrológicas em floresta tropical sazonalmente seca (FTSS

Directory of Open Access Journals (Sweden)

Eunice Maia de Andrade

2017-10-01

Full Text Available The scarcity of information on the processes of rainfall-flow limits understanding of the hydrology of dry regions of the world. In order to minimise the problem, this study was developed to investigate the influence of the characteristics of rainfall events and plant cover on the effective precipitation (Pe in a seasonally dry tropical forest (SDTF in the Northeast of Brazil. The study was carried out in two paired watersheds, one with SDTF under regeneration for 35 years (CR35 and the other under thinned SDTF for 5 years (TC. A historical series of five years (2009-2013 was analysed, with a total of 203 rainfall events, where only those rainfall events that generated a Pe > 1.0 mm were considered. CR35 had a greater number of Pe events (47 than TC (35. Rainfall depth and intensity were the factors that best explained the effective precipitation under both types of vegetation cover. The influence of herbaceous vegetation on the reduction of surface runoff was demonstrated by the smaller runoff depth and the greater potential for soil water storage in the watershed under thinned Caatinga. This fact leads to the conclusion that the technique of thinning is suitable management for Caatinga vegetation, and is capable of promoting the retention of soil water. = A escassez de informações sobre os processos chuva-deflúvio é uma limitação no entendimento da hidrologia das regiões secas do globo terrestre. Buscando minimizar esta problemática, desenvolveuse este estudo objetivando investigar as influências das características dos eventos pluviométricos e da cobertura vegetal na precipitação efetiva (Pe em floresta tropical sazonalmente seca (FTSS, no nordeste do Brasil. O estudo foi realizado em duas microbacias emparelhadas, uma com FTSS em regeneração há 35 anos (CR35 e outra com FTSS raleada há 5 anos (CR. Foi analisada uma série histórica de cinco anos (2009-2013, com um total de 203 eventos pluviométricos, sendo considerados

Air humidity as key determinant of morphogenesis and productivity of the rare temperate woodland fern Polystichum braunii.

Science.gov (United States)

Schwerbrock, R; Leuschner, C

2016-07-01

(1) Most ferns are restricted to moist and shady habitats, but it is not known whether soil moisture or atmospheric water status are decisive limiting factors, or if both are equally important. (2) Using the rare temperate woodland fern Polystichum braunii, we conducted a three-factorial climate chamber experiment (soil moisture (SM) × air humidity (RH) × air temperature (T)) to test the hypotheses that: (i) atmospheric water status (RH) exerts a similarly large influence on the fern's biology as soil moisture, and (ii) both a reduction in RH and an increase in air temperature reduce vigour and growth. (3) Nine of 11 morphological, physiological and growth-related traits were significantly influenced by an increase in RH from 65% to 95%, leading to higher leaf conductance, increased above- and belowground productivity, higher fertility, more epidermal trichomes and fewer leaf deformities under high air humidity. In contrast, soil moisture variation (from 66% to 70% in the moist to ca. 42% in the dry treatment) influenced only one trait (specific leaf area), and temperature variation (15 °C versus 19 °C during daytime) only three traits (leaf conductance, root/shoot ratio, specific leaf area); RH was the only factor affecting productivity. (4) This study is the first experimental proof for a soil moisture-independent air humidity effect on the growth of terrestrial woodland ferns. P. braunii appears to be an air humidity hygrophyte that, whithin the range of realistic environmental conditions set in this study, suffers more from a reduction in RH than in soil moisture. A climate warming-related increase in summer temperatures, however, seems not to directly threaten this endangered species. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Towards restoration of Hawaiian tropical dry forests: the Kaupulehu outplanting programme

Science.gov (United States)

Susan Cordell; Moana McClellan; Yvonne Yarber Carter; Lisa J. Hadway

2008-01-01

Hawaiian tropical dry forests contain diverse assemblages of woody canopy species, including many endemic and endangered species that warrant conservation attention before completely disappearing. Today, tropical dry forests in Hawaii are not viable ecosystems. Poor land use practices, fragmentation, non-native plant invasions, and inadequate native vegetation...

Parasitic Contamination of Vegetables From Some Markets In South ...

African Journals Online (AJOL)

Intestinal parasitic infections are among the most prevalent clinical and subclinical diseases of significant in tropical regions of the world. Fresh vegetables are important healthy diet, however in recent years there has been an increased number of reported cases of food-borne intestinal illness linked to fresh vegetables.

A spatio-temporal analysis of climatic drivers for observed changes in Sahelian vegetation productivity 1982-2007

DEFF Research Database (Denmark)

Kaspersen, Per; Fensholt, Rasmus; Huber Gharib, Silvia

2011-01-01

Linear trend analysis and seasonal trend analysis are performed on gridded data of vegetation, rainfall, solar radiation flux, and air temperature, in order to examine the influence of the past three decades of climate variability and change on the Sahelian vegetation dynamics. Per......-pixel correlation analyses are conducted on annual and monthly data, and analyses of change in the potential climatic constraints to the natural vegetation development from 1982–2007 are performed. The results reveal two distinct periods: (a) 1982–1994 marked by large increases in vegetation productivity...... and rainfall and little change in average air temperatures and solar radiation and (b) 1995–2007 characterized by no distinct trends in vegetation productivity and rainfall and increase in average air temperatures and decrease in solar radiation flux. Correlations between vegetation productivity and climatic...

The environmental impact of nitrogen in field vegetable production

NARCIS (Netherlands)

Neeteson, J.J.; Carton, O.T.

2001-01-01

Many intensive systems of field vegetable production are not sustainable because they lose excessive amounts of nitrogen (N) to the environment. Processes in the N cycle of agricultural systems include assimilation, mineralization/immobilization, nitrification, denitrification, ammonia

Yield estimation using SPOT-VEGETATION products: A case study of wheat in European countries

NARCIS (Netherlands)

Kowalik, W.; Dabrowska-Zielinska, K.; Meroni, M.; Raczka, T.U.; Wit, de A.J.W.

2014-01-01

In the period 1999-2009 ten-day SPOT-VEGETATION products of the Normalized Difference Vegetation Index (NDVI) and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR) at 1 km spatial resolution were used in order to estimate and forecast the wheat yield over Europe. The products were

Primary production in a tropical large lake: The role of phytoplankton composition

Energy Technology Data Exchange (ETDEWEB)

Darchambeau, F., E-mail: francois.darchambeau@ulg.ac.be [Chemical Oceanography Unit, University of Liège, Liège (Belgium); Sarmento, H., E-mail: hugo.sarmento@gmail.com [Department of Hydrobiology, Federal University of São Carlos, 13565-905 São Carlos, São Paulo (Brazil); Descy, J.-P., E-mail: jean-pierre.descy@unamur.be [Research Unit in Environmental and Evolutionary Biology, University of Namur, Namur (Belgium)

2014-03-01

Phytoplankton biomass and primary production in tropical large lakes vary at different time scales, from seasons to centuries. We provide a dataset made of 7 consecutive years of phytoplankton biomass and production in Lake Kivu (Eastern Africa). From 2002 to 2008, bi-weekly samplings were performed in a pelagic site in order to quantify phytoplankton composition and biomass, using marker pigments determined by HPLC. Primary production rates were estimated by 96 in situ {sup 14}C incubations. A principal component analysis showed that the main environmental gradient was linked to a seasonal variation of the phytoplankton assemblage, with a clear separation between diatoms during the dry season and cyanobacteria during the rainy season. A rather wide range of the maximum specific photosynthetic rate (P{sub Bm}) was found, ranging between 1.15 and 7.21 g carbon g{sup −1} chlorophyll a h{sup −1}, and was best predicted by a regression model using phytoplankton composition as an explanatory variable. The irradiance at the onset of light saturation (I{sub k}) ranged between 91 and 752 μE m{sup −2} s{sup −1} and was linearly correlated with the mean irradiance in the mixed layer. The inter-annual variability of phytoplankton biomass and production was high, ranging from 53 to 100 mg chlorophyll a m{sup −2} (annual mean) and from 143 to 278 g carbon m{sup −2} y{sup −1}, respectively. The degree of seasonal mixing determined annual production, demonstrating the sensitivity of tropical lakes to climate variability. A review of primary production of other African great lakes allows situating Lake Kivu productivity in the same range as that of lakes Tanganyika and Malawi, even if mean phytoplankton biomass was higher in Lake Kivu. - Highlights: • We provide a 7-year dataset of primary production in a tropical great lake. • Specific photosynthetic rate was determined by community composition. • Annual primary production varied between 143 and 278 mg C m

Harnessing Big Data for Communicable Tropical and Sub-Tropical Disorders: Implications From a Systematic Review of the Literature

Directory of Open Access Journals (Sweden)

Vincenza Gianfredi

2018-03-01

Full Text Available AimAccording to the World Health Organization (WHO, communicable tropical and sub-tropical diseases occur solely, or mainly in the tropics, thriving in hot, and humid conditions. Some of these disorders termed as neglected tropical diseases are particularly overlooked. Communicable tropical/sub-tropical diseases represent a diverse group of communicable disorders occurring in 149 countries, favored by tropical and sub-tropical conditions, affecting more than one billion people and imposing a dramatic societal and economic burden.MethodsA systematic review of the extant scholarly literature was carried out, searching in PubMed/MEDLINE and Scopus. The search string used included proper keywords, like big data, nontraditional data sources, social media, social networks, infodemiology, infoveillance, novel data streams (NDS, digital epidemiology, digital behavior, Google Trends, Twitter, Facebook, YouTube, Instagram, Pinterest, Ebola, Zika, dengue, Chikungunya, Chagas, and the other neglected tropical diseases.Results47 original, observational studies were included in the current systematic review: 1 focused on Chikungunya, 6 on dengue, 19 on Ebola, 2 on Malaria, 1 on Mayaro virus, 2 on West Nile virus, and 16 on Zika. Fifteen were dedicated on developing and validating forecasting techniques for real-time monitoring of neglected tropical diseases, while the remaining studies investigated public reaction to infectious outbreaks. Most studies explored a single nontraditional data source, with Twitter being the most exploited tool (25 studies.ConclusionEven though some studies have shown the feasibility of utilizing NDS as an effective tool for predicting epidemic outbreaks and disseminating accurate, high-quality information concerning neglected tropical diseases, some gaps should be properly underlined. Out of the 47 articles included, only 7 were focusing on neglected tropical diseases, while all the other covered communicable tropical/sub-tropical

Harnessing Big Data for Communicable Tropical and Sub-Tropical Disorders: Implications From a Systematic Review of the Literature.

Science.gov (United States)

Gianfredi, Vincenza; Bragazzi, Nicola Luigi; Nucci, Daniele; Martini, Mariano; Rosselli, Roberto; Minelli, Liliana; Moretti, Massimo

2018-01-01

According to the World Health Organization (WHO), communicable tropical and sub-tropical diseases occur solely, or mainly in the tropics, thriving in hot, and humid conditions. Some of these disorders termed as neglected tropical diseases are particularly overlooked. Communicable tropical/sub-tropical diseases represent a diverse group of communicable disorders occurring in 149 countries, favored by tropical and sub-tropical conditions, affecting more than one billion people and imposing a dramatic societal and economic burden. A systematic review of the extant scholarly literature was carried out, searching in PubMed/MEDLINE and Scopus. The search string used included proper keywords, like big data, nontraditional data sources, social media, social networks, infodemiology, infoveillance, novel data streams (NDS), digital epidemiology, digital behavior, Google Trends, Twitter, Facebook, YouTube, Instagram, Pinterest, Ebola, Zika, dengue, Chikungunya, Chagas, and the other neglected tropical diseases. 47 original, observational studies were included in the current systematic review: 1 focused on Chikungunya, 6 on dengue, 19 on Ebola, 2 on Malaria, 1 on Mayaro virus, 2 on West Nile virus, and 16 on Zika. Fifteen were dedicated on developing and validating forecasting techniques for real-time monitoring of neglected tropical diseases, while the remaining studies investigated public reaction to infectious outbreaks. Most studies explored a single nontraditional data source, with Twitter being the most exploited tool (25 studies). Even though some studies have shown the feasibility of utilizing NDS as an effective tool for predicting epidemic outbreaks and disseminating accurate, high-quality information concerning neglected tropical diseases, some gaps should be properly underlined. Out of the 47 articles included, only 7 were focusing on neglected tropical diseases, while all the other covered communicable tropical/sub-tropical diseases, and the main determinant of

Low Humidity Characteristics of Polymer-Based Capacitive Humidity Sensors

OpenAIRE

Majewski Jacek

2017-01-01

Polymer-based capacitive humidity sensors emerged around 40 years ago; nevertheless, they currently constitute large part of sensors’ market within a range of medium (climatic and industrial) humidity 20−80%RH due to their linearity, stability and cost-effectiveness. However, for low humidity values (0−20%RH) that type of sensor exhibits increasingly nonlinear characteristics with decreasing of humidity values. This paper presents the results of some experimental trials of CMOS polymer-based ...

Aluminium tolerance of Mucuna : A tropical leguminous cover crop

NARCIS (Netherlands)

Hairiah, Kurniatun

1992-01-01

In the humid tropics leaching of N and other nutrients to the subsoil may occur throughout the growing season. Typically, soils in this zone have a low soil pH, a high Al saturation of the cation exchange complex and low levels of Ca and P in the subsoil. Efficiency of N-use under such conditions

Vegetation Dynamics and Rainfall Sensitivity of the Amazon

Science.gov (United States)

Hilker, Thomas; Lyapustin, Alexei I.; Tucker, Compton J.; Hall, Forrest G.; Myneni, Ranga B.; Wang, Yujie; Bi, Jian; Mendes de Moura, Yhasmin; Sellers, Piers J.

2014-01-01

We show that the vegetation canopy of the Amazon rainforest is highly sensitive to changes in precipitation patterns and that reduction in rainfall since 2000 has diminished vegetation greenness across large parts of Amazonia. Large-scale directional declines in vegetation greenness may indicate decreases in carbon uptake and substantial changes in the energy balance of the Amazon. We use improved estimates of surface reflectance from satellite data to show a close link between reductions in annual precipitation, El Nino southern oscillation events, and photosynthetic activity across tropical and subtropical Amazonia. We report that, since the year 2000, precipitation has declined across 69% of the tropical evergreen forest (5.4 million sq km) and across 80% of the subtropical grasslands (3.3 million sq km). These reductions, which coincided with a decline in terrestrial water storage, account for about 55% of a satellite-observed widespread decline in the normalized difference vegetation index (NDVI). During El Nino events, NDVI was reduced about 16.6% across an area of up to 1.6 million sq km compared with average conditions. Several global circulation models suggest that a rise in equatorial sea surface temperature and related displacement of the intertropical convergence zone could lead to considerable drying of tropical forests in the 21st century. Our results provide evidence that persistent drying could degrade Amazonian forest canopies, which would have cascading effects on global carbon and climate dynamics.

Vegetative fallows and potential value of the neem tree (Azadirachta indica) in the tropics

Energy Technology Data Exchange (ETDEWEB)

Radwanski, S.A.; Wickens, G.E.

1981-01-01

Research into the systems of agriculture based on vegetative fallows should begin from enquiries into the shrubs and trees most efficient in restoring soil productivity and providing essential products. Azadirachta indica, of the semiarid regions is an outstanding example of a species which is not only an efficient soil ameliorant, but also provides products that are highly competitive in price and quality with petroleum-based synthetics. The launching of a research and development programme leading to the exploitation of this tree is proposed. Several projects that could be studied in such a programme are briefly outlined.

Fermented fruits and vegetables of Asia: a potential source of probiotics.

Science.gov (United States)

Swain, Manas Ranjan; Anandharaj, Marimuthu; Ray, Ramesh Chandra; Parveen Rani, Rizwana

2014-01-01

As world population increases, lactic acid fermentation is expected to become an important role in preserving fresh vegetables, fruits, and other food items for feeding humanity in developing countries. However, several fermented fruits and vegetables products (Sauerkraut, Kimchi, Gundruk, Khalpi, Sinki, etc.) have a long history in human nutrition from ancient ages and are associated with the several social aspects of different communities. Among the food items, fruits and vegetables are easily perishable commodities due to their high water activity and nutritive values. These conditions are more critical in tropical and subtropical countries which favour the growth of spoilage causing microorganisms. Lactic acid fermentation increases shelf life of fruits and vegetables and also enhances several beneficial properties, including nutritive value and flavours, and reduces toxicity. Fermented fruits and vegetables can be used as a potential source of probiotics as they harbour several lactic acid bacteria such as Lactobacillus plantarum, L. pentosus, L. brevis, L. acidophilus, L. fermentum, Leuconostoc fallax, and L. mesenteroides. As a whole, the traditionally fermented fruits and vegetables not only serve as food supplements but also attribute towards health benefits. This review aims to describe some important Asian fermented fruits and vegetables and their significance as a potential source of probiotics.

Tropical organic soils ecosystems in relation to regional water resources in southeast Asia

Energy Technology Data Exchange (ETDEWEB)

Armentano, T. V.

1982-01-01

Tropical organic soils have functioned as natural sinks for carbon, nitrogen, slfur and other nutrients for the past 4000 years or more. Topographic evolution in peat swamp forests towards greater oligotrophy has concentrated storage of the limited nutrient stock in surface soils and biota. Tropical peat systems thus share common ecosystem characteristics with northern peat bogs and certain tropical oligotrophic forests. Organic matter accumulation and high cation-exchange-capacity limit nutrient exports from undisturbed organic soils, although nutrient retention declines with increasing eutrophy and wetland productivity. Peat swamps are subject to irreversible degradation if severely altered because disturbance of vegetation, surface peats and detritus can disrupt nuttrient cycles and reduce forest recovery capacity. Drainage also greatly increases exports of nitrogen, phosphorus and other nutrients and leads to downstream eutrophication and water quality degradation. Regional planning for clean water supplies must recognize the benefits provided by natural peatlands in balancing water supplies and regulating water chemistry.

An Intercomparison of Vegetation Products from Satellite-based Observations used for Soil Moisture Retrievals

Science.gov (United States)

Vreugdenhil, Mariette; de Jeu, Richard; Wagner, Wolfgang; Dorigo, Wouter; Hahn, Sebastian; Bloeschl, Guenter

2013-04-01

Vegetation and its water content affect active and passive microwave soil moisture retrievals and need to be taken into account in such retrieval methodologies. This study compares the vegetation parameterisation that is used in the TU-Wien soil moisture retrieval algorithm to other vegetation products, such as the Vegetation Optical Depth (VOD), Net Primary Production (NPP) and Leaf Area Index (LAI). When only considering the retrieval algorithm for active microwaves, which was developed by the TU-Wien, the effect of vegetation on the backscattering coefficient is described by the so-called slope [1]. The slope is the first derivative of the backscattering coefficient in relation to the incidence angle. Soil surface backscatter normally decreases quite rapidly with the incidence angle over bare or sparsely vegetated soils, whereas the contribution of dense vegetation is fairly uniform over a large range of incidence angles. Consequently, the slope becomes less steep with increasing vegetation. Because the slope is a derivate of noisy backscatter measurements, it is characterised by an even higher level of noise. Therefore, it is averaged over several years assuming that the state of the vegetation doesn't change inter-annually. The slope is compared to three dynamic vegetation products over Australia, the VOD, NPP and LAI. The VOD was retrieved from AMSR-E passive microwave data using the VUA-NASA retrieval algorithm and provides information on vegetation with a global coverage of approximately every two days [2]. LAI is defined as half the developed area of photosynthetically active elements of the vegetation per unit horizontal ground area. In this study LAI is used from the Geoland2 products derived from SPOT Vegetation*. The NPP is the net rate at which plants build up carbon through photosynthesis and is a model-based estimate from the BiosEquil model [3, 4]. Results show that VOD and slope correspond reasonably well over vegetated areas, whereas in arid

Simulated Vegetation Response to Climate Change in California: The Importance of Seasonal Production Patterns

Science.gov (United States)

Kim, J. B.; Pitts, B.

2013-12-01

MC1 dynamic global vegetation model simulates vegetation response to climate change by simulating vegetation production, soil biogeochemistry, plant biogeography and fire. It has been applied at a wide range of spatial scales, yet the spatio-temporal patterns of simulated vegetation production, which drives the model's response to climate change, has not been examined in detail. We ran MC1 for California at a relatively fine scale, 30 arc-seconds, for the historical period (1895-2006) and for the future (2007-2100), using downscaled data from four CMIP3-based climate projections: A2 and B1 GHG emissions scenarios simulated by PCM and GFDL GCMs. The use of these four climate projections aligns our work with a body of climate change research work commissioned by the California Public Interest Energy Research (PIER) Program. The four climate projections vary not only in terms of changes in their annual means, but in the seasonality of projected climate change. We calibrated MC1 using MODIS NPP data for 2000-2011 as a guide, and adapting a published technique for adjusting simulated vegetation production by increasing the simulated plant rooting depths. We evaluated the simulation results by comparing the model output for the historical period with several benchmark datasets, summarizing by EPA Level 3 Ecoregions. Multi-year summary statistics of model predictions compare moderately well with Kuchler's potential natural vegetation map, National Biomass and Carbon Dataset, Leenhouts' compilation of fire return intervals, and, of course, the MODIS NPP data for 2000-2011. When we compared MC1's monthly NPP values with MODIS monthly GPP data (2000-2011), however, the seasonal patterns compared very poorly, with NPP/GPP ratio for spring (Mar-Apr-May) often exceeding 1, and the NPP/GPP ratio for summer (Jun-Jul-Aug) often flattening to zero. This suggests MC1's vegetation production algorithms are overly biased for spring production at the cost of summer production. We

Comparison of the tropical floras of the Sierra la Madera and the Sierra Madre Occidental, Sonora, Mexico

Science.gov (United States)

Thomas R. Van Devender; Gertrudis Yanes-Arvayo; Ana Lilia Reina-Guerrero; Melissa Valenzuela-Yanez; Maria de la Paz Montanez-Armenta; Hugo Silva-Kurumiya

2013-01-01

The floras of the tropical vegetation in the Sky Island Sierra la Madera (SMA) near Moctezuma in northeastern Sonora (30°00’N 109°18’W) and the Yécora (YEC) area in the Sierra Madre Occidental (SMO) in eastern Sonora (28°25’N 109°15”W) were compared. The areas are 175 km apart. Tropical vegetation includes foothills thornscrub (FTS) in both areas and tropical deciduous...

Food for early succession birds: relationships among arthropods, shrub vegetation, and soil

Science.gov (United States)

Richard N. Conner; Daniel Saenz; D. Brent Burt

2006-01-01

During spring and early summer, shrub- and herbaceous-level vegetation provides nesting and foraging habitat for many shrub-habitat birds. We examined relationships among arthropod biomass and abundance, foliage leaf surface area and weight, vegetation ground cover, soil characteristics, relative humidity, and temperature to evaluate what factors may influence...

The domestic benefits of tropical forests: a critical review.

Science.gov (United States)

Chomitz, K M; Kumari, K

1998-02-01

This review focuses on forests in the humid tropics and on two of their potentially most important benefits. These include hydrological benefits, such as erosion control and regulation of stream flows, and non-timber forest products, such as rubber, rattan, fruits, and nuts. The first benefit is motivational. Host countries capture only a small proportion of the global benefits, which stem from biodiversity conservation. Demonstration of palpable local benefits could help to build support for biodiversity-oriented projects. The second benefit is the magnitude of domestic benefits that could influence project financing. Sufficiently large net domestic benefits could justify financing of a project on narrow economic grounds, with biodiversity conservation as a by-product. Overall, it is noted that the quantifiable benefits of forest preservation in providing hydrological services and non-timber forest products are highly variable. These classes of domestic benefits may in general be smaller than popularly supposed. In view of this, the need for financing conservation from the Global Environmental Facility or other global sources is emphasized rather than placing the burden on domestic resources.

Potential of indirect evaporative passive cooling with embedded tubes in a humid tropical climate : applications in a typical hot humid climate

Energy Technology Data Exchange (ETDEWEB)

Garcia Chavez, J.R. [Univ. Autonoma Metropolitana-Azcapotzalco, Mexico City (Mexico). Dept. de Medio Ambiente, Laboratorio de Investigaciones en Arquitectura Bioclimatica; Givoni, B. [California Univ., Los Angeles, CA (United States); BGU, Beer Sheva (Israel); Viveros, O. [Cristobal Colon Univ., Veracruz (Mexico)

2009-07-01

The use of passive cooling techniques in buildings in hot and humid regions can reduce energy consumption while increasing thermal comfort for occupants. A study was conducted in the City of Veracruz, Mexico to investigate the performance of tubes embedded in the roof of the Gulf Meteorological Prevision Centre. Two identical insulated experimental cells were used, one serving as the control and the other one as the test unit, where the technique of embedded tubes in the roof was implemented and investigated during a typical overheating season. Results showed that this indirect evaporative cooling system is an effective strategy to reduce indoor temperatures without increasing the indoor humidity in buildings. The indoor maximum temperature was lowered by 2.72 K in the experimental test cell relative to the control unit. In addition, the resulting reduction of radiant temperatures in the test unit improved the thermal comfort of the occupants. It is expected that the implementation of this passive cooling technique will eventually contribute to reduced energy consumption and less use of air-conditioning systems in buildings, and thereby prevent emission of greenhouse gases to the atmosphere. 9 refs., 1 tab., 6 figs.

Materiel Testing in the Tropics (6th Ed)

Science.gov (United States)

1979-04-01

selected monoterpenes , fungi, and material. The field phase of the study employed two methods to inventory the am- bient organic compounds in the tropics...volatile compounds from vegetation effluents ( monoterpenes ) were not found in measurable quantities by air sampling. The second method collected condensed...laboratory. It was found that ambient levels of volatile organic compounds that derive their origin as vegetation effluents ( monoterpenes ) were not among the

Production and marketing challenges of vegetable farming: a case ...

African Journals Online (AJOL)

Production and marketing challenges of vegetable farming: a case study of Kumasi metropolis of Ashanti region, Ghana. ... Current Issue · Archives · Journal Home > Vol 9, No 1 (2016) >. Log in or Register to get access to full text downloads.

Irrigation water consumption modelling of a soilless cucumber crop under specific greenhouse conditions in a humid tropical climate

Directory of Open Access Journals (Sweden)

Galo Alberto Salcedo

Full Text Available ABSTRACT: The irrigation water consumption of a soilless cucumber crop under greenhouse conditions in a humid tropical climate has been evaluated in this paper in order to improve the irrigation water and fertilizers management in these specific conditions. For this purpose, a field experiment was conducted. Two trials were carried out during the years 2011 and 2014 in an experimental farm located in Vinces (Ecuador. In each trial, the complete growing cycle of a cucumber crop grown under a greenhouse was evaluated. Crop development was monitored and a good fit to a sigmoidal Gompertz type growth function was reported. The daily water uptake of the crop was measured and related to the most relevant indoor climate variables. Two different combination methods, namely the Penman-Monteith equation and the Baille equation, were applied. However, the results obtained with these combination methods were not satisfactory due to the poor correlation between the climatic variables, especially the incoming radiation, and the crop's water uptake (WU. On contrary, a good correlation was reported between the crop's water uptake and the leaf area index (LAI, especially in the initial crop stages. However, when the crop is fully developed, the WU stabilizes and becomes independent from the LAI. A preliminary model to simulate the water uptake of the crop was adjusted using the data obtained in the first experiment and then validated with the data of the second experiment.

Developmental acclimation to low or high humidity conditions affect starvation and heat resistance of Drosophila melanogaster.

Science.gov (United States)

Parkash, Ravi; Ranga, Poonam; Aggarwal, Dau Dayal

2014-09-01

Several Drosophila species originating from tropical humid localities are more resistant to starvation and heat stress than populations from high latitudes but mechanistic bases of such physiological changes are largely unknown. In order to test whether humidity levels affect starvation and heat resistance, we investigated developmental acclimation effects of low to high humidity conditions on the storage and utilization of energy resources, body mass, starvation survival, heat knockdown and heat survival of D. melanogaster. Isofemale lines reared under higher humidity (85% RH) stored significantly higher level of lipids and showed greater starvation survival hours but smaller in body size. In contrast, lines reared at low humidity evidenced reduced levels of body lipids and starvation resistance. Starvation resistance and lipid storage level were higher in females than males. However, the rate of utilization of lipids under starvation stress was lower for lines reared under higher humidity. Adult flies of lines reared at 65% RH and acclimated under high or low humidity condition for 200 hours also showed changes in resistance to starvation and heat but such effects were significantly lower as compared with developmental acclimation. Isofemale lines reared under higher humidity showed greater heat knockdown time and heat-shock survival. These laboratory observations on developmental and adult acclimation effects of low versus high humidity conditions have helped in explaining seasonal changes in resistance to starvation and heat of the wild-caught flies of D. melanogaster. Thus, we may suggest that wet versus drier conditions significantly affect starvation and heat resistance of D. melanogaster. Copyright © 2014 Elsevier Inc. All rights reserved.

Vegetation Structure and Temperature Regimes of Tropical Alpine Treelines

NARCIS (Netherlands)

Bader, M.Y.; Rietkerk, M.G.; Bregt, A.K.

2007-01-01

Alpine treeline ecotones can be gradual transitions, abrupt boundaries, or patchy mosaics, and these different patterns may indicate important processes and dynamic properties. We present observed spatial patterns of a wide range of tropical treelines and try to explain these patterns. Treelines

Vegetation structure and temperature regimes of tropical alpine treelines

NARCIS (Netherlands)

Bader, M.; Rietkerk, M.; Bregt, A.K.

2007-01-01

Alpine treeline ecotones can be gradual transitions, abrupt boundaries, or patchy mosaics, and these different patterns may indicate important processes and dynamic properties. We present observed spatial patterns of a wide range of tropical treelines and try to explain these patterns. Treelines

Towards sustainable vegetable production around agro-pastoral dams in Northern Benin

NARCIS (Netherlands)

Kpéra, G.N.; Segnon, Alcade C.; Saïdou, Aliou; Mensah, Guy A.; Aarts, Noelle; Zijpp, van der Akke J.

2017-01-01

Background: Rehabilitation and optimized utilization of agro-pastoral dams (APDs), especially for vegetable production, has been recently promoted to boost agricultural production and ensure food security in Benin. However, little information was available on APDs' agricultural potentials and

Effects of liana load, tree diameter and distances between conspecifics on seed production in tropical timber trees

NARCIS (Netherlands)

Nabe-Nielsen, J.; Kollmann, J.; Peña-Claros, M.

2009-01-01

Seed production in tropical timber trees is limited by abiotic resources, pollination and pre-dispersal seed predation. Resource availability is influenced by the number of competing trees and by lianas that often reach high densities in disturbed parts of tropical forests. The distance between

High-resolution mapping of biomass burning emissions in tropical regions across three continents

Science.gov (United States)

Shi, Yusheng; Matsunaga, Tsuneo; Saito, Makoto

2015-04-01

Biomass burning emissions from open vegetation fires (forest fires, savanna fires, agricultural waste burning), human waste and biofuel combustion contain large amounts of trace gases (e.g., CO2, CH4, and N2O) and aerosols (BC and OC), which significantly impact ecosystem productivity, global atmospheric chemistry, and climate . With the help of recently released satellite products, biomass density based on satellite and ground-based observation data, and spatial variable combustion factors, this study developed a new high-resolution emissions inventory for biomass burning in tropical regions across three continents in 2010. Emissions of trace gases and aerosols from open vegetation burning are estimated from burned areas, fuel loads, combustion factors, and emission factors. Burned areas were derived from MODIS MCD64A1 burned area product, fuel loads were mapped from biomass density data sets for herbaceous and tree-covered land based on satellite and ground-based observation data. To account for spatial heterogeneity in combustion factors, global fractional tree cover (MOD44B) and vegetation cover maps (MCD12Q1) were introduced to estimate the combustion factors in different regions by using their relationship with tree cover under less than 40%, between 40-60% and above 60% conditions. For emission factors, the average values for each fuel type from field measurements are used. In addition to biomass burning from open vegetation fires, the emissions from human waste (residential and dump) burning and biofuel burning in 2010 were also estimated for 76 countries in tropical regions across the three continents and then allocated into each pixel with 1 km grid based on the population density (Gridded Population of the World v3). Our total estimates for the tropical regions across the three continents in 2010 were 17744.5 Tg CO2, 730.3 Tg CO, 32.0 Tg CH4, 31.6 Tg NOx, 119.2 Tg NMOC, 6.3 Tg SO2, 9.8 NH3 Tg, 81.8 Tg PM2.5, 48.0 Tg OC, and 5.7 Tg BC, respectively. Open

Using satellite data on meteorological and vegetation characteristics and soil surface humidity in the Land Surface Model for the vast territory of agricultural destination

Science.gov (United States)

Muzylev, Eugene; Startseva, Zoya; Uspensky, Alexander; Vasilenko, Eugene; Volkova, Elena; Kukharsky, Alexander

2017-04-01

The model of water and heat exchange between vegetation covered territory and atmosphere (LSM, Land Surface Model) for vegetation season has been developed to calculate soil water content, evapotranspiration, infiltration of water into the soil, vertical latent and sensible heat fluxes and other water and heat balances components as well as soil surface and vegetation cover temperatures and depth distributions of moisture and temperature. The LSM is suited for utilizing satellite-derived estimates of precipitation, land surface temperature and vegetation characteristics and soil surface humidity for each pixel. Vegetation and meteorological characteristics being the model parameters and input variables, correspondingly, have been estimated by ground observations and thematic processing measurement data of scanning radiometers AVHRR/NOAA, SEVIRI/Meteosat-9, -10 (MSG-2, -3) and MSU-MR/Meteor-M № 2. Values of soil surface humidity has been calculated from remote sensing data of scatterometers ASCAT/MetOp-A, -B. The case study has been carried out for the territory of part of the agricultural Central Black Earth Region of European Russia with area of 227300 km2 located in the forest-steppe zone for years 2012-2015 vegetation seasons. The main objectives of the study have been: - to built estimates of precipitation, land surface temperatures (LST) and vegetation characteristics from MSU-MR measurement data using the refined technologies (including algorithms and programs) of thematic processing satellite information matured on AVHRR and SEVIRI data. All technologies have been adapted to the area of interest; - to investigate the possibility of utilizing satellite-derived estimates of values above in the LSM including verification of obtained estimates and development of procedure of their inputting into the model. From the AVHRR data there have been built the estimates of precipitation, three types of LST: land skin temperature Tsg, air temperature at a level of

Plant gene bank and vegetable varieties biodiversity in Smederevska Palanka

Directory of Open Access Journals (Sweden)

Pavlović Nenad

2011-01-01

Full Text Available Biodiversity protection and preservation of genetic variability is based on the fact that plant varieties are irreplaceable in production process and that they are more and more jeopardized by urban and industrial development. The most common way of preserving and at the same time the safest way is a storage in a gene bank. Prior to storage comes collecting, studying and replanting for Institute Gene Bank, Central State Gene Bank and for Regional Gene Banks. Institute for Vegetable Crops in Smederevska Palanka preserves a wide variety of vegetable germplasm. This is, so called, work collection, used as a gene resource for breeding purposes. Seed samples are stored at 4±2°C and 50% relative humidity. At the moment, the collection has 2265 samples. Almost all samples have the passport data, but only 10% of samples have been further characterized and evaluated.

Validation and Analysis of SRTM and VCL Data Over Tropical Volcanoes

Science.gov (United States)

Mouginis-Mark, Peter J.

2004-01-01

The focus of our investigation was on the application of digital topographic data in conducting first-order volcanological and structural studies of tropical volcanoes, focusing on the Java, the Philippines and the Galapagos Islands. Kilauea volcano, Hawaii, served as our test site for SRTM data validation. Volcanoes in humid tropical environments are frequently cloud covered, typically densely vegetated and erode rapidly, so that it was expected that new insights into the styles of eruption of these volcanoes could be obtained from analysis of topographic data. For instance, in certain parts of the world, such as Indonesia, even the regional structural context of volcanic centers is poorly known, and the distribution of volcanic products (e.g., lava flows, pyroclastic flows, and lahars) are not well mapped. SRTM and Vegetation Canopy Lidar (VCL) data were expected to provide new information on these volcanoes. Due to the cancellation of the VCL mission, we did not conduct any lidar studies during the duration of this project. Digital elevation models (DEMs) such as those collected by SRTM provide quantitative information about the time-integrated typical activity on a volcano and allow an assessment of the spatial and temporal contributions of various constructional and destructional processes to each volcano's present morphology. For basaltic volcanoes, P_c?w!m-d and Garbed (2000) have shown that gradual slopes (less than 5 deg.) occur where lava and tephra pond within calderas or in the saddles between adjacent volcanoes, as well as where lava deltas coalesce to form coastal plains. Vent concentration zones (axes of rift zones) have slopes ranging from 10 deg. to 12 deg. Differential vertical growth rates between vent concentration zones and adjacent mostly-lava flanks produce steep constructional slopes up to 40". The steepest slopes (locally approaching 90 deg.) are produced by fluvial erosion, caldera collapse, faulting, and catastrophic avalanches, all of

Inverse relationship between present-day tropical precipitation and its sensitivity to greenhouse warming

Science.gov (United States)

Ham, Yoo-Geun; Kug, Jong-Seong; Choi, Jun-Young; Jin, Fei-Fei; Watanabe, Masahiro

2018-01-01

Future changes in rainfall have serious impacts on human adaptation to climate change, but quantification of these changes is subject to large uncertainties in climate model projections. To narrow these uncertainties, significant efforts have been made to understand the intermodel differences in future rainfall changes. Here, we show a strong inverse relationship between present-day precipitation and its future change to possibly calibrate future precipitation change by removing the present-day bias in climate models. The results of the models with less tropical (40° S-40° N) present-day precipitation are closely linked to the dryness over the equatorial central-eastern Pacific, and project weaker regional precipitation increase due to the anthropogenic greenhouse forcing1-6 with stronger zonal Walker circulation. This induces Indo-western Pacific warming through Bjerknes feedback, which reduces relative humidity by the enhanced atmospheric boundary-layer mixing in the future projection. This increases the air-sea humidity difference to enhance tropical evaporation and the resultant precipitation. Our estimation of the sensitivity of the tropical precipitation per 1 K warming, after removing a common bias in the present-day simulation, is about 50% greater than the original future multi-model projection.

Modeling Linkages Between Effective Impervious Surface and Urban Vegetation Productivity in Semi-arid Environments

Science.gov (United States)

Shields, C. A.; Tague, C.

2010-12-01

With a majority of the world's population now living in urban areas, the role of vegetation in urban ecosystems warrants increased attention. We address the question of how the fine scale (significantly impact the productivity of vegetation and uptake of C and N. To gain insight into how landscape features influence vegetation productivity, we use a coupled ecohydrogic model to estimate impacts of the amount and arrangement of impervious surfaces on vegetation water use. We use the model to explore how concepts from research in natural semi-arid ecosystems can be applied in the urban context. Ecological research in semi-arid ecosystems has shown that the arrangement of vegetated and bare surfaces plays a key role in regulating both runoff and ecosystem water use and productivity. Systems that include a mixture of bare and vegetated surfaces, for example, tend to show less runoff and more productivity than those with more homogeneous cover. In some instances, patchiness of bare and vegetated surfaces is more important than total vegetated area in determining rates of runoff and vegetation use of rainfall. In an urban context, impervious surfaces can be viewed as analogous to the bare surfaces present in undeveloped ecosystems. We consider not only the total impervious area (TIA), but also the effect of impervious area with a direct hydrologic connection to the stream network, effective impervious area (EIA). While increases in total impervious area (TIA) have been widely shown to impact catchment hydrology, the role of effective impervious area (EIA) has been less extensively studied. A consensus is emerging from the literature that EIA is as important or even more important than TIA as an indicator of catchment response to urbanization. Ecohydrologic models offer a tool to quantify the role of EIA on water availability and plant productivity and demonstrate the potential of urban areas to act as C or N sinks (and minimize the impacts such as increased storm runoff

Effect of Tropical Climatic Conditions on the Stability of Cefaclor Dry ...

African Journals Online (AJOL)

Purpose: Two critical factors that govern the stability of pharmaceutical formulations in the tropics are humidity and temperature. This study was carried out to investigate the effect of moisture sorption at two different storage conditions on Cefaclor dry powder for oral suspension and predict the effect of moisture interaction on ...

Progress in tropical isotope dendroclimatology

Science.gov (United States)

Evans, M. N.; Schrag, D. P.; Poussart, P. F.; Anchukaitis, K. J.

2005-12-01

The terrestrial tropics remain an important gap in the growing high resolution proxy network used to characterize the mean state and variability of the hydrological cycle. Here we review early efforts to develop a new class of proxy paleorainfall/humidity indicators using intraseasonal to interannual-resolution stable isotope data from tropical trees. The approach invokes a recently published model of oxygen isotopic composition of alpha-cellulose, rapid methods for cellulose extraction from raw wood, and continuous flow isotope ratio mass spectrometry to develop proxy chronological, rainfall and growth rate estimates from tropical trees, even those lacking annual rings. Isotopically-derived age models may be confirmed for modern intervals using trees of known age, radiocarbon measurements, direct measurements of tree diameter, and time series replication. Studies are now underway at a number of laboratories on samples from Costa Rica, northwestern coastal Peru, Indonesia, Thailand, New Guinea, Paraguay, Brazil, India, and the South American Altiplano. Improved sample extraction chemistry and online pyrolysis techniques should increase sample throughput, precision, and time series replication. Statistical calibration together with simple forward modeling based on the well-observed modern period can provide for objective interpretation of the data. Ultimately, replicated data series with well-defined uncertainties can be entered into multiproxy efforts to define aspects of tropical hydrological variability associated with ENSO, the meridional overturning circulation, and the monsoon systems.

Investigation on the Patterns of Global Vegetation Change Using a Satellite-Sensed Vegetation Index

Directory of Open Access Journals (Sweden)

Ainong Li

2010-06-01

Full Text Available The pattern of vegetation change in response to global change still remains a controversial issue. A Normalized Difference Vegetation Index (NDVI dataset compiled by the Global Inventory Modeling and Mapping Studies (GIMMS was used for analysis. For the period 1982–2006, GIMMS-NDVI analysis indicated that monthly NDVI changes show homogenous trends in middle and high latitude areas in the northern hemisphere and within, or near, the Tropic of Cancer and Capricorn; with obvious spatio-temporal heterogeneity on a global scale over the past two decades. The former areas featured increasing vegetation activity during growth seasons, and the latter areas experienced an even greater amplitude in places where precipitation is adequate. The discussion suggests that one should be cautious of using the NDVI time-series to analyze local vegetation dynamics because of its coarse resolution and uncertainties.

Tropical Soil Chemistry

DEFF Research Database (Denmark)

Borggaard, Ole K.

and environmental protection. Tropical Soil Chemistry by Ole K. Borggaard provides an overview of the composition, occurrence, properties, processes, formation, and environmental vulnerability of various tropical soil types (using American Soil Taxonomy for classification). The processes and the external factors...... soil chemical issues are also presented to assess when, why, and how tropical soils differ from soils in other regions. This knowledge can help agricultural specialists in the tropics establish sustainable crop production. Readers are assumed to be familiar with basic chemistry, physics...

Empirical downscaling of atmospheric key variables above a tropical glacier surface (Cordillera Blanca, Peru)

Science.gov (United States)

Hofer, M.; Kaser, G.; Mölg, T.; Juen, I.; Wagnon, P.

2009-04-01

Glaciers in the outer tropical Cordillera Blanca (Peru, South America) are of major socio-economic importance, since glacier runoff represents the primary water source during the dry season, when little or no rainfall occurs. Due to their location at high elevations, the glaciers moreover provide important information about climate change in the tropical troposphere, where measurements are sparse. This study targets the local reconstruction of air temperature, specific humidity and wind speed above the surface of an outer tropical glacier from NCEP/NCAR reanalysis data as large scale predictors. Since a farther scope is to provide input data for process based glacier mass balance modelling, the reconstruction pursues a high temporal resolution. Hence an empirical downscaling scheme is developed, based on a few years' time series of hourly observations from automatic weather stations, located at the glacier Artesonraju and nearby moraines (Northern Cordillera Blanca). Principal component and multiple regression analyses are applied to define the appropriate spatial downscaling domain, suitable predictor variables, and the statistical transfer functions. The model performance is verified using an independent data set. The best predictors are lower tropospheric air temperature and specific humidity, at reanalysis model grid points that represent the Bolivian Altiplano, located in the South of the Cordillera Blanca. The developed downscaling model explaines a considerable portion (more than 60%) of the diurnal variance of air temperature and specific humidity at the moraine stations, and air temperature above the glacier surface. Specific humidity above the glacier surface, however, can be reconstructed well in the seasonal, but not in the required diurnal time resolution. Wind speed can only be poorly determined by the large scale predictors (r² lower than 0.3) at both sites. We assume a complex local interaction between valley and glacier wind system to be the main

PLANT BREEDING IS A SOLUTION FOR IMPORT SUBSTITUTION IN VEGETABLE PRODUCTION

Directory of Open Access Journals (Sweden)

V. F. Pivovarov

2017-01-01

Full Text Available The vegetable production  is one of the economic sectors  that  provides  the  population  with  foodstuff  products with high biological values. To achieve independence in production  of the agricultural foodstuffs,  the part of imported  products should not be beyond 25 % from total volume of foodstuffs  fabricated. As a result of national breeding program, the varieties and hybrids adapted to different growing conditions, with resistance to  local races of pathogens, temperature stresses, and ground frosts were developed to provide the sustainable production of vegetables with high nutritional and medicinal qualities. The varieties and hybrids F1  of white  head cabbage that have been created for the last 5 years are distinguished from foreign ones by taste qualities, appropriate pickling characteristics with increased  sugar,  and  decreased  cellulose  contents. The local onion varieties combine long shelf life, early maturing, well bulb formation, high dry matter content (18-20% and ability to form the bulb for one year. The cucumber  is  the  traditional  vegetable crop  in  Russia and very profitable for greenhouse enterprises. Breeders have developed bee-pollinated and parthenocarpic hybrids well adapted to local growing conditions and  suitable  for   open  field   cultivation   in  different regions of Russia. Parthenocarpic heterotic hybrids of the  multi-propose  use, corresponding  to  the  modern variety model with high productivity, early-ripening, bunch ovary disposition, resistance to abiotic stresses, and  most  harmful  diseases. The carrot  and  red  beet varieties with  high nutritional  qualities, long shelf-life, ecological plasticity that are widely used for seed production have been created. The varieties of nightshade crops have been developed to cultivate in NonChernozem zone, Far East, Western Siberia, the Middle Belt of Russia and the south of Russia, are also

Re-examining the Non-Linear Moisture-Precipitation Relationship over the Tropical Oceans.

Science.gov (United States)

Rushley, S S; Kim, D; Bretherton, C S; Ahn, M-S

2018-01-28

Bretherton et al. (2004) used the Special Sensor Microwave Imager (SSM/I) version 5 product to derive an exponential curve that describes the relationship between precipitation and column relative humidity (CRH) over the tropical oceans. The curve, which features a precipitation pickup at a CRH of about 0.75 and a rapid increase of precipitation with CRH after the pickup, has been widely used in the studies of the tropical atmosphere. This study re-examines the moisture-precipitation relationship by using the version 7 SSM/I data, in which several biases in the previous version are corrected, and evaluates the relationship in the Coupled Model Intercomparison Project phase 5 (CMIP5) models. In the revised exponential curve derived using the updated satellite data, the precipitation pick-up occurs at a higher CRH (~0.8), and precipitation increases more slowly with CRH than in the previous curve. In most CMIP5 models, the precipitation pickup is too early due to the common model bias of overestimated (underestimated) precipitation in the dry (wet) regime.

Insight into the product film formed on Ni-advanced weathering steel in a tropical marine atmosphere

Science.gov (United States)

Wu, Wei; Cheng, Xuequn; Hou, Huaxing; Liu, Bo; Li, Xiaogang

2018-04-01

The product film formed on Ni-advanced weathering steel in a tropical marine environment was investigated in detail through outdoor exposure by using diverse surface analysis techniques combined with electrochemical impedance spectroscopy and scanning kelvin probe measurements. The results showed that the product film was mainly composed of nanophasic goethite in the inner layer and maghemite, akaganeite, and hematite in the outer layer. Moreover, the resistance to atmospheric corrosion gradually increased from the outermost product film to the innermost film. Ni was significantly enriched in the inner layer in the form of the spinel phase NiFe2O4, which transformed lepidocrocite to fine-grained goethite, withstood the invasion of chloridion, and improved the corrosion potential of the product film in a tropical marine atmosphere.

Biofilm formation and sporulation by Bacillus cereus on a stainless steel surface and subsequent resistance of vegetative cells and spores to chlorine, chlorine dioxide, and a peroxyacetic acid-based sanitizer.

Science.gov (United States)

Ryu, Jee-Hoon; Beuchat, Larry R

2005-12-01

Biofilm formation by Bacillus cereus 038-2 on stainless steel coupons, sporulation in the biofilm as affected by nutrient availability, temperature, and relative humidity, and the resistance of vegetative cells and spores in biofilm to sanitizers were investigated. Total counts in biofilm formed on coupons immersed in tryptic soy broth (TSB) at 12 and 22 degrees C consisted of 99.94% of vegetative cells and 0.06% of spores. Coupons on which biofilm had formed were immersed in TSB or exposed to air with 100, 97, 93, or 85% relative humidity. Biofilm on coupons immersed in TSB at 12 degrees C for an additional 6 days or 22 degrees C for an additional 4 days contained 0.30 and 0.02% of spores, respectively, whereas biofilm exposed to air with 100 or 97% relative humidity at 22 degrees C for 4 days contained 10 and 2.5% of spores, respectively. Sporulation did not occur in biofilm exposed to 93 or 85% relative humidity at 22 degrees C. Treatment of biofilm on coupons that had been immersed in TSB at 22 degrees C with chlorine (50 microg/ml), chlorine dioxide (50 microg/ml), and a peroxyacetic acid-based sanitizer (Tsunami 200, 40 microg/ml) for 5 min reduced total cell counts (vegetative cells plus spores) by 4.7, 3.0, and 3.8 log CFU per coupon, respectively; total cell counts in biofilm exposed to air with 100% relative humidity were reduced by 1.5, 2.4, and 1.1 log CFU per coupon, respectively, reflecting the presence of lower numbers of vegetative cells. Spores that survived treatment with chlorine dioxide had reduced resistance to heat. It is concluded that exposure of biofilm formed by B. cereus exposed to air at high relative humidity (> or =97%) promotes the production of spores. Spores and, to a lesser extent, vegetative cells embedded in biofilm are protected against inactivation by sanitizers. Results provide new insights to developing strategies to achieve more effective sanitation programs to minimize risks associated with B. cereus in biofilm formed on

PRIMARY PRODUCTION OF SEAGRASS BEDS IN SOUTH SULAWESI (INDONESIA) - A COMPARISON OF HABITATS, METHODS AND SPECIES

NARCIS (Netherlands)

ERFTEMEIJER, PLA; OSINGA, R; MARS, AE

Primary production of tropical seagrass meadows was studied between April and August 1990 in South Sulawesi, Indonesia. Oxygen evolution studies in enclosures over seagrass vegetation revealed gross community production values between 900 and 4400 mg C m-2 day-1. Assumed community respiration ranged

Effect of the addition of fatty by-products from the refining of vegetable oil on methane production in co-digestion.

Science.gov (United States)

Torrijos, M; Sousbie, P; Badey, L; Bosque, F; Steyer, J P

2012-01-01

The purpose of this work was to investigate the effects of the addition of by-products from the refining of vegetable oil on the behavior of co-digestion reactors treating a mixture of grass, cow dung and fruit and vegetable waste. Three by-products were used: one soapstock, one used winterization earth and one skimming of aeroflotation of the effluents. Three 15 l reactors were run in parallel and fed five times a week. In a first phase of 4 weeks, the three reactors were fed with the co-digestion substrates alone (grass, cow dung and fruit and vegetable waste) at an organic loading rate (OLR) of 1.5 g VS/kg d (VS: volatile solids). Then, a different by-product from the refining of oil was added to the feed of each reactor at an OLR of 0.5 g VS/kg d, generating a 33% increase in the OLR. The results show that the addition of by-products from the refining of oil is an efficient way of increasing the methane production of co-digestion reactors thanks to high methane yield of such by-products (0.69-0.77 l CH(4)/g VS loaded). In fact, in this work, it was possible to raise the methane production of the reactors by about 60% through a 33% increase in the OLR thanks to the addition of the by-products from the refining of vegetable oil.

Emissions of biogenic volatile organic compounds and subsequent photochemical production of secondary organic aerosol in mesocosm studies of temperate and tropical plant species

Science.gov (United States)

Wyche, K. P.; Ryan, A. C.; Hewitt, C. N.; Alfarra, M. R.; McFiggans, G.; Carr, T.; Monks, P. S.; Smallbone, K. L.; Capes, G.; Hamilton, J. F.; Pugh, T. A. M.; MacKenzie, A. R.

2014-12-01

Silver birch (Betula pendula) and three Southeast Asian tropical plant species (Ficus cyathistipula, Ficus benjamina and Caryota millis) from the pantropical fig and palm genera were grown in a purpose-built and environment-controlled whole-tree chamber. The volatile organic compounds emitted from these trees were characterised and fed into a linked photochemical reaction chamber where they underwent photo-oxidation under a range of controlled conditions (relative humidity or RH ~65-89%, volatile organic compound-to-NOx or VOC / NOx ~3-9 and NOx ~2 ppbV). Both the gas phase and the aerosol phase of the reaction chamber were monitored in detail using a comprehensive suite of on-line and off-line chemical and physical measurement techniques. Silver birch was found to be a high monoterpene and sesquiterpene but low isoprene emitter, and its emissions were observed to produce measurable amounts of secondary organic aerosol (SOA) via both nucleation and condensation onto pre-existing seed aerosol (YSOA 26-39%). In contrast, all three tropical species were found to be high isoprene emitters with trace emissions of monoterpenes and sesquiterpenes. In tropical plant experiments without seed aerosol there was no measurable SOA nucleation, but aerosol mass was shown to increase when seed aerosol was present. Although principally isoprene emitting, the aerosol mass produced from tropical fig was mostly consistent (i.e. in 78 out of 120 aerosol mass calculations using plausible parameter sets of various precursor specific yields) with condensation of photo-oxidation products of the minor volatile organic compounds (VOCs) co-emitted; no significant aerosol yield from condensation of isoprene oxidation products was required in the interpretations of the experimental results. This finding is in line with previous reports of organic aerosol loadings consistent with production from minor biogenic VOCs co-emitted with isoprene in principally isoprene-emitting landscapes in Southeast

Status of compost usage and its performance on vegetable production in Monga areas of Bangladesh

OpenAIRE

G.K.M.M. Rahman

2014-01-01

The present study was carried out to assess the existing status of compost usage on vegetable production and determine the overall effect of household waste compost (HWC) on growth and yield of vegetables and enhancement of soil fertility in the monga areas of Bangladesh. A field survey was conducted on 152 sampled farmers during 2010 to 2011. Questionnaire containing both closed and open-ended questions were used to assess existing production practices of vegetables using compost in both hom...

Soil and water pollution in a banana production region in tropical Mexico

NARCIS (Netherlands)

Geissen, V.; Que Ramos, F.; Bastidas-Bastidas, de P.J.; Díaz-González, G.; Bello-Mendoza, R.; Huerta-Lwanga, E.; Ruiz-Suárez, L.E.

2010-01-01

The effects of abundant Mancozeb (Mn, Zn— bisdithiocarbamate) applications (2.5 kg ha-1week-1 for 10 years) on soil and surface-, subsurface- and groundwater pollution were monitored in a banana production region of tropical Mexico. In soils, severe manganese accumulation was observed, wheras the

Mapping swamp timothy (Cripsis schenoides) seed productivity using spectral values and vegetation indices in managed wetlands

Energy Technology Data Exchange (ETDEWEB)

Rahilly, P.J.A.; Li, D.; Guo, Q.; Zhu, J.; Ortega, R.; Quinn, N.W.T.; Harmon, T.C.

2010-01-15

This work examines the potential to predict the seed productivity of a key wetland plant species using spectral reflectance values and spectral vegetation indices. Specifically, the seed productivity of swamp timothy (Cripsis schenoides) was investigated in two wetland ponds, managed for waterfowl habitat, in California's San Joaquin Valley. Spectral reflectance values were obtained and associated spectral vegetation indices (SVI) calculated from two sets of high resolution aerial images (May 11, 2006 and June 9, 2006) and were compared to the collected vegetation data. Vegetation data were collected and analyzed from 156 plots for total aboveground biomass, total aboveground swamp timothy biomass, and total swamp timothy seed biomass. The SVI investigated included the Simple Ratio (SR), Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI), Transformed Soil Adjusted Vegetation Index (TSAVI), Modified Soil Adjusted Vegetation Index (MSAVI), and Global Environment Monitoring Index (GEMI). We evaluated the correlation of the various SVI with in situ vegetation measurements for linear, quadratic, exponential and power functions. In all cases, the June image provided better predictive capacity relative to May, a result that underscores the importance of timing imagery to coincide with more favorable vegetation maturity. The north pond with the June image using SR and the exponential function (R{sup 2}=0.603) proved to be the best predictor of swamp timothy seed productivity. The June image for the south pond was less predictive, with TSAVI and the exponential function providing the best correlation (R{sup 2}=0.448). This result was attributed to insufficient vegetal cover in the south pond (or a higher percentage of bare soil) due to poor drainage conditions which resulted in a delay in swamp timothy germination. The results of this work suggest that spectral reflectance can be used to estimate seed productivity in managed seasonal

Global vegetation change predicted by the modified Budyko model

Energy Technology Data Exchange (ETDEWEB)

Monserud, R.A.; Tchebakova, N.M.; Leemans, R. (US Department of Agriculture, Moscow, ID (United States). Intermountain Research Station, Forest Service)

1993-09-01

A modified Budyko global vegetation model is used to predict changes in global vegetation patterns resulting from climate change (CO[sub 2] doubling). Vegetation patterns are predicted using a model based on a dryness index and potential evaporation determined by solving radiation balance equations. Climate change scenarios are derived from predictions from four General Circulation Models (GCM's) of the atmosphere (GFDL, GISS, OSU, and UKMO). All four GCM scenarios show similar trends in vegetation shifts and in areas that remain stable, although the UKMO scenario predicts greater warming than the others. Climate change maps produced by all four GCM scenarios show good agreement with the current climate vegetation map for the globe as a whole, although over half of the vegetation classes show only poor to fair agreement. The most stable areas are Desert and Ice/Polar Desert. Because most of the predicted warming is concentrated in the Boreal and Temperate zones, vegetation there is predicted to undergo the greatest change. Most vegetation classes in the Subtropics and Tropics are predicted to expand. Any shift in the Tropics favouring either Forest over Savanna, or vice versa, will be determined by the magnitude of the increased precipitation accompanying global warming. Although the model predicts equilibrium conditions to which many plant species cannot adjust (through migration or microevolution) in the 50-100 y needed for CO[sub 2] doubling, it is not clear if projected global warming will result in drastic or benign vegetation change. 72 refs., 3 figs., 3 tabs.

Ground level environmental protein concentrations in various ecuadorian environments: potential uses of aerosolized protein for ecological research

Science.gov (United States)

Staton, Sarah J.R.; Woodward, Andrea; Castillo, Josemar A.; Swing, Kelly; Hayes, Mark A.

2014-01-01

Large quantities of free protein in the environment and other bioaerosols are ubiquitous throughout terrestrial ground level environments and may be integrative indicators of ecosystem status. Samples of ground level bioaerosols were collected from various ecosystems throughout Ecuador, including pristine humid tropical forest (pristine), highly altered secondary humid tropical forest (highly altered), secondary transitional very humid forest (regrowth transitional), and suburban dry montane deforested (suburban deforested). The results explored the sensitivity of localized aerosol protein concentrations to spatial and temporal variations within ecosystems, and their value for assessing environmental change. Ecosystem specific variations in environmental protein concentrations were observed: pristine 0.32 ± 0.09 μg/m3, highly altered 0.07 ± 0.05 μg/m3, regrowth transitional 0.17 ± 0.06 μg/m3, and suburban deforested 0.09 ± 0.04 μg/m3. Additionally, comparisons of intra-environmental differences in seasonal/daily weather (dry season 0.08 ± 0.03 μg/m3 and wet season 0.10 ± 0.04 μg/m3), environmental fragmentation (buffered 0.19 ± 0.06 μg/m3 and edge 0.15 ± 0.06 μg/m3), and sampling height (ground level 0.32 ± 0.09 μg/m3 and 10 m 0.24 ± 0.04 μg/m3) demonstrated the sensitivity of protein concentrations to environmental conditions. Local protein concentrations in altered environments correlated well with satellite-based spectral indices describing vegetation productivity: normalized difference vegetation index (NDVI) (r2 = 0.801), net primary production (NPP) (r2 = 0.827), leaf area index (LAI) (r2 = 0.410). Moreover, protein concentrations distinguished the pristine site, which was not differentiated in spectral indices, potentially due to spectral saturation typical of highly vegetated environments. Bioaerosol concentrations represent an inexpensive method to increase understanding of environmental changes, especially in densely vegetated

CYCLICAL MANNER OF VEGETABLE PRODUCTION INDUSTRY; THE EFFICIENCY OF GREENHOUSE BUSINESS

Directory of Open Access Journals (Sweden)

O. N. Krylov

2017-01-01

Full Text Available Economical  efficiency  of  agricultural  industry  is  a major characteristic of the level of development of an enterprise. A profit from product sale depends on volume and structure of product  sales, self-cost as well as the level of  sales price.  Thus, the gross revenue from cultivated crops and vegetable cultivars can be observed at the time of fruit harvesting. The total sum of  the gross earnings from  the harvest, determining the  efficiency  of  enterprise can  be  calculated  as a product of values of daily price and mass of total harvest. There are no challenging points in the condition of permanent price and vegetable harvest. Even the registration of average-sales prices for vegetable doesn’t make the production difficult. But real market situation essentially differs from accepted practice to register average-sales prices with relatively permanent vegetable  harvest.  The  price  indexes  of  sales  for tomato and cucumber produced in greenhouse in Udmurt Republic with showing the dynamic of retail price for vegetables were presented in the article. It was shown  that  prices  of  tomatoes  and cucumbers had the seasonal factor that meant weekly price wavering.  The  temporal  row  harvest  of  cucumber ‘Tseres           F1’  and  tomato  ‘Admiro  F1’  produced  at Zaviyalovskiy greenhouse enterprise was  described. The average derivation between nearest and last harvest was in the  gap  23%  to  29%  in cucumber  and reached up to 70% in tomato. The values of such derivations were occasionally provoked and determined by some inter-enterprise factors. The construction  of trend lines for such series and further line evaluation with  the aid of  determination  coefficient  R2  showed extremely low quality of model  of the kind y=a•x+b. The value of R2 cubic  polynominals was in the limits R2=0.32-0.46. Essentially, plans for vegetable production

Quantifying Vegetation Structure with Lightweight, Rapid-Scanning Terrestrial Lidar

Science.gov (United States)

Paynter, I.; Genest, D.; Saenz, E. J.; Strahler, A. H.; Li, Z.; Peri, F.; Schaaf, C.

2016-12-01

Light Detection and Ranging (lidar) is proving a competent technology for observing vegetation structure. Terrestrial laser scanners (TLS) are ground-based instruments which utilize hundreds of thousands to millions of lidar observations to provide detailed structural and reflective information of their surroundings. TLS has enjoyed initial success as a validation tool for satellite and airborne estimates of vegetation structure, and are producing independent estimates with increasing accuracy. Reconstruction techniques for TLS observations of vegetation have also improved rapidly, especially for trees. However, uncertainties and challenges still remain in TLS modelling of vegetation structure, especially in geometrically complex ecosystems such as tropical forests (where observation extent and density is hampered by occlusion) and highly temporally dynamic coastal ecosystems (such as saltmarshes and mangroves), where observations may be restricted to narrow microstates. Some of these uncertainties can be mitigated, and challenges met, through the use of lidar instruments optimized for favorable deployment logistics through low weight, rapid scanning, and improved durability. We have conducted studies of vegetation structure in temperate and tropical forests, saltmarshes and mangroves, utilizing a highly portable TLS with considerable deployment flexibility, the Compact Biomass Lidar (CBL). We show results from studies in the temperate Long Term Ecological Research site of Harvard Forest (MA, USA); the tropical forested long-term Carbono sites of La Selva Biological Station (Sarapiqui, Costa Rica); and the saltmarsh LTER of Plum Island (MA, USA). These results demonstrate the improvements to observations in these ecosystems which are facilitated by the specifications of the CBL (and similar TLS) which are optimized for favorable deployment logistics and flexibility. We show the benefits of increased numbers of scanning positions, and specialized deployment

Chapter 14. Radionuclides in vegetal production and food processing

International Nuclear Information System (INIS)

Toelgyessy, J.; Harangozo, M.

2000-01-01

This is a chapter of textbook of radioecology for university students. In this chapter authors deal with problems connected with using of radionuclides in vegetal production and food processing. Chapter consist of next parts: (1) Influence of radiation on foods; (2) Radiation sterilisation in health service

An Inexpensive, Stable, and Accurate Relative Humidity Measurement Method for Challenging Environments.

Science.gov (United States)

Zhang, Wei; Ma, Hong; Yang, Simon X

2016-03-18

In this research, an improved psychrometer is developed to solve practical issues arising in the relative humidity measurement of challenging drying environments for meat manufacturing in agricultural and agri-food industries. The design in this research focused on the structure of the improved psychrometer, signal conversion, and calculation methods. The experimental results showed the effect of varying psychrometer structure on relative humidity measurement accuracy. An industrial application to dry-cured meat products demonstrated the effective performance of the improved psychrometer being used as a relative humidity measurement sensor in meat-drying rooms. In a drying environment for meat manufacturing, the achieved measurement accuracy for relative humidity using the improved psychrometer was ±0.6%. The system test results showed that the improved psychrometer can provide reliable and long-term stable relative humidity measurements with high accuracy in the drying system of meat products.

East African Cenozoic vegetation history.

Science.gov (United States)

Linder, Hans Peter

2017-11-01

The modern vegetation of East Africa is a complex mosaic of rainforest patches; small islands of tropic-alpine vegetation; extensive savannas, ranging from almost pure grassland to wooded savannas; thickets; and montane grassland and forest. Here I trace the evolution of these vegetation types through the Cenozoic. Paleogene East Africa was most likely geomorphologically subdued and, as the few Eocene fossil sites suggest, a woodland in a seasonal climate. Woodland rather than rainforest may well have been the regional vegetation. Mountain building started with the Oligocene trap lava flows in Ethiopia, on which rainforest developed, with little evidence of grass and none of montane forests. The uplift of the East African Plateau took place during the middle Miocene. Fossil sites indicate the presence of rainforest, montane forest and thicket, and wooded grassland, often in close juxtaposition, from 17 to 10 Ma. By 10 Ma, marine deposits indicate extensive grassland in the region and isotope analysis indicates that this was a C 3 grassland. In the later Miocene rifting, first of the western Albertine Rift and then of the eastern Gregory Rift, added to the complexity of the environment. The building of the high strato-volcanos during the later Mio-Pliocene added environments suitable for tropic-alpine vegetation. During this time, the C 3 grassland was replaced by C 4 savannas, although overall the extent of grassland was reduced from the mid-Miocene high to the current low level. Lake-level fluctuations during the Quaternary indicate substantial variation in rainfall, presumably as a result of movements in the intertropical convergence zone and the Congo air boundary, but the impact of these fluctuations on the vegetation is still speculative. I argue that, overall, there was an increase in the complexity of East African vegetation complexity during the Neogene, largely as a result of orogeny. The impact of Quaternary climatic fluctuation is still poorly understood

Comparative energy input–output and financial analyses of greenhouse and open field vegetables production in West Java, Indonesia

International Nuclear Information System (INIS)

Kuswardhani, Nita; Soni, Peeyush; Shivakoti, Ganesh P.

2013-01-01

This paper estimates energy consumption per unit floor area of greenhouse and open field for tomato, chili and lettuce production. Primary data were collected from 530 vegetable farmers during Jan–Dec, 2010 in West Java, Indonesia. Energy estimates were calculated from actual amount of inputs and outputs and corresponding conversion factors. Results reveal that the total input energy used in greenhouse (GH) production of tomato, chili (medium and high land) and lettuce were 47.62, 41.55, 58.84, and 24.54 GJ/ha respectively. Whereas, the requirement of total input energy for open field (OF) production of tomato, chili (medium and high land) and lettuce were 49.01, 41.04, 57.94 and 23.87 GJ/ha, respectively. The ratio of output to input energy was higher in greenhouse production (0.85, 0.45 and 0.49) than open field vegetable production (0.52, 0.175 and 0.186) for tomato, chili medium land and chili highland, respectively, but output–input ratio of lettuce open field production was twice as that of greenhouse vegetable production. Financial analysis revealed higher mean net returns from greenhouse vegetable production as 7043 $/ha (922–15,299 $/ha) when compared to 571 $/ha (44–1172 $/ha) from open field vegetable production. Among the greenhouse vegetables, tomato cultivation was the most profitable in terms of energy efficiency and financial productivity. - Highlights: ► Energy input–output analysis is carried out to compare vegetables production in greenhouse and open field. ► Tomato, Chili and Lettuce production in West Java, Indonesia. ► Economic analysis is conducted to compare the two production systems

Global patterns of NDVI-indicated vegetation extremes and their sensitivity to climate extremes

International Nuclear Information System (INIS)

Liu Guo; Liu Hongyan; Yin Yi

2013-01-01

Extremes in climate have significant impacts on ecosystems and are expected to increase under future climate change. Extremes in vegetation could capture such impacts and indicate the vulnerability of ecosystems, but currently have not received a global long-term assessment. In this study, a robust method has been developed to detect significant extremes (low values) in biweekly time series of global normalized difference vegetation index (NDVI) from 1982 to 2006 and thus to acquire a global pattern of vegetation extreme frequency. This pattern coincides with vegetation vulnerability patterns suggested by earlier studies using different methods over different time spans, indicating a consistent mechanism of regulation. Vegetation extremes were found to aggregate in Amazonia and in the semi-arid and semi-humid regions in low and middle latitudes, while they seldom occurred in high latitudes. Among the environmental variables studied, extreme low precipitation has the highest slope against extreme vegetation. For the eight biomes analyzed, these slopes are highest in temperate broadleaf forest and temperate grassland, suggesting a higher sensitivity in these environments. The results presented here contradict the hypothesis that vegetation in water-limited semi-arid and semi-humid regions might be adapted to drought and suggest that vegetation in these regions (especially temperate broadleaf forest and temperate grassland) is highly prone to vegetation extreme events under more severe precipitation extremes. It is also suggested here that more attention be paid to precipitation-induced vegetation changes than to temperature-induced events. (letter)

Sweet potato weevil (Cylas formicarius) incidence in the humid lowlands of Papua New Guinea

NARCIS (Netherlands)

Powell, K.S.; Hartemink, A.E.; Eganae, J.F.; Walo, C.; Poloma, S.

2001-01-01

Sweet potato is the main staple crop in PNG and this paper presents a study from the humid lowlands of the Morobe Province. Three experiments were carried out at two locations (Hobu and Unitech) to evaluate the effect of inorganic fertiliser inputs and fallow vegetation on the incidence of sweet

Heavy Metals in the Vegetables Collected from Production Sites

Directory of Open Access Journals (Sweden)

Hassan Taghipour

2013-12-01

Full Text Available Background: Contamination of vegetable crops (as an important part of people's diet with heavy metals is a health concern. Therefore, monitoring levels of heavy metals in vegetables can provide useful information for promoting food safety. The present study was carried out in north-west of Iran (Tabriz on the content of heavy metals in vegetable crops. Methods: Samples of vegetables including kurrat (n=20 (Allium ampeloprasumssp. Persicum, onion (n=20 (Allium cepa and tomato (n=18 (Lycopersiconesculentum var. esculentum, were collected from production sites in west of Tabriz and analyzed for presence of Cd, Cr, Cu, Ni, Pb and Zn by atomic absorption spectroscopy (AAS after extraction by aqua regia method (drying, grounding and acid digestion. Results: Mean ± SD (mg/kg DW concentrations of Cd, Cu, Cr, Ni and Zn were 0.32 ± 0.58, 28.86 ± 28.79, 1.75 ± 2.05, 6.37± 5.61 and 58.01 ± 27.45, respectively. Cr, Cu and Zn were present in all the samples and the highest concentrations were observed in kurrat (leek. Levels of Cd, Cr and Cu were higher than the acceptable limits. There was significant difference in levels of Cr (P<0.05 and Zn (P<0.001 among the studied vegetables. Positive correlation was observed between Cd:Cu (R=0.659, P<0.001 Cr:Ni (R=0.326, P<0.05 and Cr:Zn (R=0.308, P<0.05. Conclusion: Level of heavy metals in some of the analyzed vegetables, especially kurrat samples, was higher than the standard levels. Considering the possible health outcomes due to the consumption of contaminated vegetables, it is required to take proper actions for avoiding people's chronic exposure.

Glacial-interglacial vegetation dynamics in South Eastern Africa coupled to sea surface temperature variations in the Western Indian Ocean

Directory of Open Access Journals (Sweden)

L. M. Dupont

2011-11-01

Full Text Available Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between the Indian and Atlantic Oceans. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ∼120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (spanning the past 342 Ka have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials, the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods was favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including fynbos-like species of the high-altitude Grassland biome for the last glacial as well as for other glacial periods of the past 300 Ka.

Accumulation and health risk of heavy metals in vegetables from harmless and organic vegetable production systems of China.

Science.gov (United States)

Chen, Yong; Hu, Wenyou; Huang, Biao; Weindorf, David C; Rajan, Nithya; Liu, Xiaoxiao; Niedermann, Silvana

2013-12-01

Heavy metal accumulation in vegetables is a growing concern for public health. Limited studies have elucidated the heavy metal accumulation characteristics and health risk of different vegetables produced in different facilities such as greenhouses and open-air fields and under different management modes such as harmless and organic. Given the concern over the aforementioned factors related to heavy metal accumulation, this study selected four typical greenhouse vegetable production bases, short-term harmless greenhouse vegetable base (SHGVB), middle-term harmless greenhouse vegetable base (MHGVB), long-term harmless greenhouse vegetable base (LHGVB), and organic greenhouse vegetable base (OGVB), in Nanjing City, China to study heavy metal accumulation in different vegetables and their associated health risks. Results showed that soils and vegetables from SHGVB and OGVB apparently accumulated fewer certain heavy metals than those from other bases, probably due to fewer planting years and special management, respectively. Greenhouse conditions significantly increased certain soil heavy metal concentrations relative to open-air conditions. However, greenhouse conditions did not significantly increase concentrations of As, Cd, Cu, Hg, and Zn in leaf vegetables. In fact, under greenhouse conditions, Pb accumulation was effectively reduced. The main source of soil heavy metals was the application of large amounts of low-grade fertilizer. There was larger health risk for producers' children to consume vegetables from the three harmless vegetable bases than those of residents' children. The hazard index (HI) over a large area exceeded 1 for these two kinds of children in the MHGVB and LHGVB. There was also a slight risk in the SHGVB for producers' children solely. However, the HI of the whole area of the OGVB for two kinds of children was below 1, suggesting low risk of heavy metal exposure through the food chain. Notably, the contribution rate of Cu and Zn to the HI were

Comparison between remote sensing and a dynamic vegetation model for estimating terrestrial primary production of Africa.

Science.gov (United States)

Ardö, Jonas

2015-12-01

Africa is an important part of the global carbon cycle. It is also a continent facing potential problems due to increasing resource demand in combination with climate change-induced changes in resource supply. Quantifying the pools and fluxes constituting the terrestrial African carbon cycle is a challenge, because of uncertainties in meteorological driver data, lack of validation data, and potentially uncertain representation of important processes in major ecosystems. In this paper, terrestrial primary production estimates derived from remote sensing and a dynamic vegetation model are compared and quantified for major African land cover types. Continental gross primary production estimates derived from remote sensing were higher than corresponding estimates derived from a dynamic vegetation model. However, estimates of continental net primary production from remote sensing were lower than corresponding estimates from the dynamic vegetation model. Variation was found among land cover classes, and the largest differences in gross primary production were found in the evergreen broadleaf forest. Average carbon use efficiency (NPP/GPP) was 0.58 for the vegetation model and 0.46 for the remote sensing method. Validation versus in situ data of aboveground net primary production revealed significant positive relationships for both methods. A combination of the remote sensing method with the dynamic vegetation model did not strongly affect this relationship. Observed significant differences in estimated vegetation productivity may have several causes, including model design and temperature sensitivity. Differences in carbon use efficiency reflect underlying model assumptions. Integrating the realistic process representation of dynamic vegetation models with the high resolution observational strength of remote sensing may support realistic estimation of components of the carbon cycle and enhance resource monitoring, providing suitable validation data is available.

Responses to elevated carbon dioxide in artificial tropical ecosystems

International Nuclear Information System (INIS)

Koerner, C.; Arnone, J.A. III

1992-01-01

Carbon, nutrient, and water balance as well as key plant and soil processes were simultaneously monitored for humid tropical plant communities treated with CO 2 -enriched atmospheres. Despite vigorous growth, no significant differences in stand biomass, leaf area index, nitrogen or water consumption, or leaf stomatal behavior were detected between ambient and elevated CO 2 treatments. Major responses under elevated CO 2 included massive starch accumulation in the tops of canopies, increased fine-root production, and a doubling of CO 2 evolution from the soil. Stimulated rhizosphere activity was accompanied by increased loss of soil carbon and increased mineral nutrient leaching. This study points at the inadequacy of scaling-up from physiological baseline to ecosystems without accounting for interactions among components, and it emphasizes the urgent need for whole-system experimental approaches in global-change research

Unique Microbial Diversity and Metabolic Pathway Features of Fermented Vegetables From Hainan, China

Science.gov (United States)

Peng, Qiannan; Jiang, Shuaiming; Chen, Jieling; Ma, Chenchen; Huo, Dongxue; Shao, Yuyu; Zhang, Jiachao

2018-01-01

Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria were the most abundant. Lactobacillus plantarum was the most abundant species, followed by Lactobacillus fermentum, Lactobacillus pentosaceus, and Weissella cibaria. These species were present in each sample with average absolute content values greater than 1% and were thus defined as core microbiota. Analysis results based on the alpha and beta diversities of the microbial communities showed that the microbial profiles of the fermented vegetables differed significantly based on the regions and raw materials used, and the species of the vegetables had a greater effect on the microbial community structure than the region from where they were harvested. Regarding microbial functional metabolism, we observed an enrichment of metabolic pathways, including membrane transport, replication and repair and translation, which implied that the microbial metabolism in the fermented vegetables tended to be vigorous. In addition, Lactobacillus plantarum and Lactobacillus fermentum were calculated to be major metabolic pathway contributors. Finally, we constructed a network to better explain correlations among the core microbiota and metabolic pathways. This study facilitates an understanding of the differences in microbial profiles and fermentation pathways involved in the production of fermented vegetables, establishes a basis for optimally selecting microorganisms to manufacture high-quality fermented vegetable products, and lays the foundation for better utilizing tropical microbial

Unique Microbial Diversity and Metabolic Pathway Features of Fermented Vegetables From Hainan, China

Directory of Open Access Journals (Sweden)

Qiannan Peng

2018-03-01

Full Text Available Fermented vegetables are typically traditional foods made of fresh vegetables and their juices, which are fermented by beneficial microorganisms. Herein, we applied high-throughput sequencing and culture-dependent technology to describe the diversities of microbiota and identify core microbiota in fermented vegetables from different areas of Hainan Province, and abundant metabolic pathways in the fermented vegetables were simultaneously predicted. At the genus level, Lactobacillus bacteria were the most abundant. Lactobacillus plantarum was the most abundant species, followed by Lactobacillus fermentum, Lactobacillus pentosaceus, and Weissella cibaria. These species were present in each sample with average absolute content values greater than 1% and were thus defined as core microbiota. Analysis results based on the alpha and beta diversities of the microbial communities showed that the microbial profiles of the fermented vegetables differed significantly based on the regions and raw materials used, and the species of the vegetables had a greater effect on the microbial community structure than the region from where they were harvested. Regarding microbial functional metabolism, we observed an enrichment of metabolic pathways, including membrane transport, replication and repair and translation, which implied that the microbial metabolism in the fermented vegetables tended to be vigorous. In addition, Lactobacillus plantarum and Lactobacillus fermentum were calculated to be major metabolic pathway contributors. Finally, we constructed a network to better explain correlations among the core microbiota and metabolic pathways. This study facilitates an understanding of the differences in microbial profiles and fermentation pathways involved in the production of fermented vegetables, establishes a basis for optimally selecting microorganisms to manufacture high-quality fermented vegetable products, and lays the foundation for better utilizing

SMAP Multi-Temporal Soil Moisture and Vegetation Optical Depth Retrievals in Vegetated Regions Including Higher-Order Soil-Canopy Interactions

Science.gov (United States)

Feldman, A.; Akbar, R.; Konings, A. G.; Piles, M.; Entekhabi, D.

2017-12-01

The Soil Moisture Active Passive (SMAP) mission utilizes a zeroth order radiative transfer model, known as the tau-omega model, to retrieve soil moisture from microwave brightness temperature observations. This model neglects first order scattering which is significant at L-Band in vegetated regions, or 30% of land cover. Previous higher order algorithms require extensive in-situ measurements and characterization of canopy layer physical properties. We propose a first order retrieval algorithm that approximately characterizes the eight first order emission pathways using rough surface reflectivity, vegetation optical depth (VOD), and scattering albedo terms. The recently developed Multi-Temporal Dual Channel Algorithm (MT-DCA) then retrieves these three parameters in a forward model without ancillary information under the assumption of temporally static albedo and constant vegetation water content between three day SMAP revisits. The approximated scattering terms are determined to be conservative estimates of analytically derived first order scattering terms. In addition, we find the first order algorithm to be more sensitive to surface emission than the tau-omega model. The simultaneously retrieved VOD, previously demonstrated to be proportional to vegetation water content, can provide insight into vegetation dynamics in regions with significant phenology. Specifically, dry tropical forests exhibit an increase in VOD during the dry season in alignment with prior studies that suggest that certain vegetative species green up during the dry season despite limited water availability. VOD retrieved using the first order algorithm and MT-DCA framework can therefore contribute to understanding of tropical forests' role in the carbon, energy, and water cycles, which has yet to be fully explained.

Technology versus Agro-Ecology in Designing Vegetable Production Systems in the Netherlands

NARCIS (Netherlands)

Haan, de J.J.; Sukkel, W.; Stilma, E.S.C.

2010-01-01

Current open field vegetable production systems in the Netherlands do not meet market and societal demands. These demands could not be fulfilled by adapting current production systems. Other kinds of production systems are needed and therefore two types of systems are designed by 1) a technological

A large-scale field assessment of carbon stocks in human-modified tropical forests.

Science.gov (United States)

Berenguer, Erika; Ferreira, Joice; Gardner, Toby Alan; Aragão, Luiz Eduardo Oliveira Cruz; De Camargo, Plínio Barbosa; Cerri, Carlos Eduardo; Durigan, Mariana; Cosme De Oliveira Junior, Raimundo; Vieira, Ima Célia Guimarães; Barlow, Jos

2014-12-01

Tropical rainforests store enormous amounts of carbon, the protection of which represents a vital component of efforts to mitigate global climate change. Currently, tropical forest conservation, science, policies, and climate mitigation actions focus predominantly on reducing carbon emissions from deforestation alone. However, every year vast areas of the humid tropics are disturbed by selective logging, understory fires, and habitat fragmentation. There is an urgent need to understand the effect of such disturbances on carbon stocks, and how stocks in disturbed forests compare to those found in undisturbed primary forests as well as in regenerating secondary forests. Here, we present the results of the largest field study to date on the impacts of human disturbances on above and belowground carbon stocks in tropical forests. Live vegetation, the largest carbon pool, was extremely sensitive to disturbance: forests that experienced both selective logging and understory fires stored, on average, 40% less aboveground carbon than undisturbed forests and were structurally similar to secondary forests. Edge effects also played an important role in explaining variability in aboveground carbon stocks of disturbed forests. Results indicate a potential rapid recovery of the dead wood and litter carbon pools, while soil stocks (0-30 cm) appeared to be resistant to the effects of logging and fire. Carbon loss and subsequent emissions due to human disturbances remain largely unaccounted for in greenhouse gas inventories, but by comparing our estimates of depleted carbon stocks in disturbed forests with Brazilian government assessments of the total forest area annually disturbed in the Amazon, we show that these emissions could represent up to 40% of the carbon loss from deforestation in the region. We conclude that conservation programs aiming to ensure the long-term permanence of forest carbon stocks, such as REDD+, will remain limited in their success unless they effectively

Fuelwood collection and its impacts on a protected tropical mountain forest in Uganda

NARCIS (Netherlands)

Sassen, M.; Sheil, D.; Giller, K.E.

2015-01-01

Local communities who live close to protected tropical forests often depend on them for woodfuel, their main source of energy. The impacts of fuelwood extraction in humid forests are rarely studied, yet the extraction of wood for fuel can impact forest structure, function and biodiversity. We

Methods of humidity determination Part II: Determination of material humidity

OpenAIRE

Rübner, Katrin; Balköse, Devrim; Robens, E.

2008-01-01

Part II covers the most common methods of measuring the humidity of solid material. State of water near solid surfaces, gravimetric measurement of material humidity, measurement of water sorption isotherms, chemical methods for determination of water content, measurement of material humidity via the gas phase, standardisation, cosmonautical observations are reviewed.

Tropical Veterinarian: Submissions

African Journals Online (AJOL)

Author Guidelines. 2012 Author Guidelines: Instructions to Authors: TROPICAL VETERINARIAN welcomes original work on all aspects of veterinary science as practiced in the Tropics, including livestock production and management, animal disease (domestic and wild), various aspects of preventive medicine and public ...

Design of Tropical Flowers Environmental Parameters Wireless Monitoring System Based on MSP430

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Huang Jian-Qing

2016-01-01

Full Text Available Considering the importance of real-time monitoring tropical flower environment parameters, the paper designs a wireless monitoring system based on MSP430F149 for tropical flower growing parameters. The proposed system uses sensor nodes to obtain data of temperature, humidity and light intensity, sink node to collect data from sensor nodes through wireless sensor network, and monitoring center to process data downloaded from the sink node through RS232 serial port. The node hardware platform is composed of a MSP430F149 processor, AM2306 and NHZD10AI sensors used to adopt temperature, humidity and light intensity data, and an nRF905 RF chip used to receive and send data. The node software, operated in IAR Embedded Workbench, adopts C Language to do node data collection and process, wireless transmission and serial port communication. The software of monitoring center develops in VB6.0, which can provide vivid and explicit real-time monitoring platform for flower farmers.

Vegetation productivity responses to drought on tribal lands in the four corners region of the Southwest USA

Science.gov (United States)

El-Vilaly, Mohamed Abd Salam; Didan, Kamel; Marsh, Stuart E.; van Leeuwen, Willem J. D.; Crimmins, Michael A.; Munoz, Armando Barreto

2018-03-01

For more than a decade, the Four Corners Region has faced extensive and persistent drought conditions that have impacted vegetation communities and local water resources while exacerbating soil erosion. These persistent droughts threaten ecosystem services, agriculture, and livestock activities, and expose the hypersensitivity of this region to inter-annual climate variability and change. Much of the intermountainWestern United States has sparse climate and vegetation monitoring stations, making fine-scale drought assessments difficult. Remote sensing data offers the opportunity to assess the impacts of the recent droughts on vegetation productivity across these areas. Here, we propose a drought assessment approach that integrates climate and topographical data with remote sensing vegetation index time series. Multisensor Normalized Difference Vegetation Index (NDVI) time series data from 1989 to 2010 at 5.6 km were analyzed to characterize the vegetation productivity changes and responses to the ongoing drought. A multi-linear regression was applied to metrics of vegetation productivity derived from the NDVI time series to detect vegetation productivity, an ecosystem service proxy, and changes. The results show that around 60.13% of the study area is observing a general decline of greenness ( pchallenges to the region's already stressed ecosystems. Whereas the results provide additional insights into this isolated and vulnerable region, the drought assessment approach used in this study may be adapted for application in other regions where surface-based climate and vegetation monitoring record is spatially and temporally limited.

Using Food Grade Lye “omushelekha” in the Formulation of Health Products from Commonly Consumed African Indigenous Vegetables and Vegetable Combinations

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Florence O Habwe

2011-05-01

Full Text Available Background: Lye, sodium hydroxide and potassium hydroxide has been used over the years in food preparation including the preparation of vegetables and dried meat products, washing or chemical peeling of fruits and vegetables, cocoa processing, caramel production, poultry scalding and cooking among others. Lye is believed to improve the organoleptic properties and also enhances the nutritional value to the products.Objective: To assess the effect of food grade lye on the levels of copper and iron in the raw, boiled and boiled-fried single vegetables and vegetable combinations treated with and without food grade lye.Methods: Single vegetables, Crotalaria occroleuca, Solanum scabrum, Vigna unguiculata and Amaranthus blitum and their combinations were cooled and kept in the fridge at 4oCs. Elemental analysis was done for the raw, boiled and boiled-fried samples using Atomic Absorption Spectrophotometry (AAS under standard conditions using wavelengths of 248.3nm for iron and 324.2nm for copper. Paired t-test was used to compare the iron and copper levels of the boiled and boiled-fried vegetables while the independent t-test was done to assess the levels of iron and copper in the raw, boiled and boiled fried samples.Results: Boiled-fried samples recorded higher content of iron and copper than the boiled ones. A combination of Amaranthus blitum-Crotolaria occloreuca boiled without lye boiled-fried with lye, and boiled-fried without lye had the highest copper contents of 1.66mg/100gram, 4.56mg/100gram, and 4.56mg/100gram respectively, compared to Amaranthus blitum aloneFunctional Foods in Heals and Disease 2011; 5:189-197(3.48mg/100gram and Crotolaria occloreuca (0.42mg/100gram. A combination of Amaranthus blitum-Crotolaria occloreuca boiled in non-lye water, and those boiled-fried with and without lye had the highest extractable iron of 557mg/100g, 859.2mg/100g, and 859.2mg/100g respectively. Iron content was high in the Solanum scabrum (281.1mg/100g

Spatial patterns of primary productivity derived from the Dynamic Habitat Indices predict patterns of species richness and distributions in the tropics

Science.gov (United States)

Suttidate, Naparat

Humans are changing the Earth's ecosystems, which has profound consequences for biodiversity. To understand how species respond to these changes, biodiversity science requires accurate assessments of biodiversity. However, biodiversity assessments are still limited in tropical regions. The Dynamic Habitat Indices (DHIs), derived from satellite data, summarize dynamic patterns of annual primary productivity: (a) cumulative annual productivity, (b) minimum annual productivity, and (c) seasonal variation in productivity. The DHIs have been successfully used in temperate regions, but not yet in the tropics. My goal was to evaluate the importance of primary productivity measured via the DHIs for assessing patterns of species richness and distributions in Thailand. First, I assessed the relationships between the DHIs and tropical bird species richness. I also evaluated the complementarity of the DHIs and topography, climate, latitudinal gradients, habitat heterogeneity, and habitat area in explaining bird species richness. I found that among three DHIs, cumulative annual productivity was the most important factor in explaining bird species richness and that the DHIs outperformed other environmental variables. Second, I developed texture measures derive from DHI cumulative annual productivity, and compared them to habitat composition and fragmentation as predictors of tropical forest bird distributions. I found that adding texture measures to habitat composition and fragmentation models improved the prediction of tropical bird distributions, especially area- and edge-sensitive tropical forest bird species. Third, I predicted the effects of trophic interactions between primary productivity, prey, and predators in relation to habitat connectivity for Indochinese tigers (Panthera tigris). I found that including trophic interactions improved habitat suitability models for tigers. However, tiger habitat is highly fragmented with few dispersal corridors. I also identified

Pasture shade and farm management effects on cow productivity in the tropics

OpenAIRE

Ainsworth, Justin A.W.; Moe, Stein R.; Skarpe, Christina

2012-01-01

This is the postprint version of the article. The published article can be located at the publisher's webpage Shade, provided by trees within pastures, can affect cattle productivity through mitigating heat stress and by altering understorey pasture growth and cattle behaviour. Models for daily milk yield and body condition were used to evaluate the effect of pasture shade on dual purpose cow productivity within a silvopastoral system in a dry tropical province of Nicaragua. Daily milk yie...

The Role of Natural Products in Drug Discovery and Development against Neglected Tropical Diseases

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Peter Mubanga Cheuka

2016-12-01

Full Text Available Endemic in 149 tropical and subtropical countries, neglected tropical diseases (NTDs affect more than 1 billion people annually, including 875 million children in developing economies. These diseases are also responsible for over 500,000 deaths per year and are characterized by long-term disability and severe pain. The impact of the combined NTDs closely rivals that of malaria and tuberculosis. Current treatment options are associated with various limitations including widespread drug resistance, severe adverse effects, lengthy treatment duration, unfavorable toxicity profiles, and complicated drug administration procedures. Natural products have been a valuable source of drug regimens that form the cornerstone of modern pharmaceutical care. In this review, we highlight the potential that remains untapped in natural products as drug leads for NTDs. We cover natural products from plant, marine, and microbial sources including natural-product-inspired semi-synthetic derivatives which have been evaluated against the various causative agents of NTDs. Our coverage is limited to four major NTDs which include human African trypanosomiasis (sleeping sickness, leishmaniasis, schistosomiasis and lymphatic filariasis.

Development of livestock production in the tropics: farm and farmers' perspectives.

Science.gov (United States)

Oosting, S J; Udo, H M J; Viets, T C

2014-08-01

Because of an increasing demand for animal-source foods, an increasing desire to reduce poverty and an increasing need to reduce the environmental impact of livestock production, tropical farming systems with livestock must increase their productivity. An important share of the global human and livestock populations are found within smallholder mixed-crop-livestock systems, which should, therefore, contribute significantly towards this increase in livestock production. The present paper argues that increased livestock production in smallholder mixed-crop-livestock systems faces many constraints at the level of the farm and the value chain. The present paper aims to describe and explain the impact of increased production from the farm and farmers' perspective, in order to understand the constraints for increased livestock production. A framework is presented that links farming systems to livestock value chains. It is concluded that farming systems that pass from subsistence to commercial livestock production will: (1) shift from rural to urban markets; (2) become part of a different value chain (with lower prices, higher demands for product quality and increased competition from peri-urban producers and imports); and (3) have to face changes in within-farm mechanisms and crop-livestock relationships. A model study showed that feed limitation, which is common in tropical farming systems with livestock, implies that maximum herd output is achieved with small herd sizes, leaving low-quality feeds unutilised. Maximal herd output is not achieved at maximal individual animal output. Having more animals than required for optimal production - which is often the case as a larger herd size supports non-production functions of livestock, such as manure production, draught, traction and capital storage - goes at the expense of animal-source food output. Improving low-quality feeds by treatment allows keeping more animals while maintaining the same level of production. Ruminant

Assessment of Plant Functional Types in Tropical Arid and Semi-Arid Ecosystems of India Using Remote Sensing Data and GIS