Tropical radioecology

CERN Document Server

Baxter, M

2012-01-01

Tropical Radioecology is a guide to the wide range of scientific practices and principles of this multidisciplinary field. It brings together past and present studies in the tropical and sub-tropical areas of the planet, highlighting the unique aspects of tropical systems. Until recently, radioecological models for tropical environments have depended upon data derived from temperate environments, despite the differences of these regions in terms of biota and abiotic conditions. Since radioactivity can be used to trace environmental processes in humans and other biota, this book offers examples of studies in which radiotracers have been used to assess biokinetics in tropical biota. Features chapters, co-authored by world experts, that explain the origins, inputs, distribution, behaviour, and consequences of radioactivity in tropical and subtropical systems. Provides comprehensive lists of relevant data and identifies current knowledge gaps to allow for targeted radioecological research in the future. Integrate...

Disaggregating Tropical Disease Prevalence by Climatic and Vegetative Zones within Tropical West Africa.

Science.gov (United States)

Beckley, Carl S; Shaban, Salisu; Palmer, Guy H; Hudak, Andrew T; Noh, Susan M; Futse, James E

2016-01-01

Tropical infectious disease prevalence is dependent on many socio-cultural determinants. However, rainfall and temperature frequently underlie overall prevalence, particularly for vector-borne diseases. As a result these diseases have increased prevalence in tropical as compared to temperate regions. Specific to tropical Africa, the tendency to incorrectly infer that tropical diseases are uniformly prevalent has been partially overcome with solid epidemiologic data. This finer resolution data is important in multiple contexts, including understanding risk, predictive value in disease diagnosis, and population immunity. We hypothesized that within the context of a tropical climate, vector-borne pathogen prevalence would significantly differ according to zonal differences in rainfall, temperature, relative humidity and vegetation condition. We then determined if these environmental data were predictive of pathogen prevalence. First we determined the prevalence of three major pathogens of cattle, Anaplasma marginale, Babesia bigemina and Theileria spp, in the three vegetation zones where cattle are predominantly raised in Ghana: Guinea savannah, semi-deciduous forest, and coastal savannah. The prevalence of A. marginale was 63%, 26% for Theileria spp and 2% for B. bigemina. A. marginale and Theileria spp. were significantly more prevalent in the coastal savannah as compared to either the Guinea savanna or the semi-deciduous forest, supporting acceptance of the first hypothesis. To test the predictive power of environmental variables, the data over a three year period were considered in best subsets multiple linear regression models predicting prevalence of each pathogen. Corrected Akaike Information Criteria (AICc) were assigned to the alternative models to compare their utility. Competitive models for each response were averaged using AICc weights. Rainfall was most predictive of pathogen prevalence, and EVI also contributed to A. marginale and B. bigemina prevalence

Disaggregating Tropical Disease Prevalence by Climatic and Vegetative Zones within Tropical West Africa.

Directory of Open Access Journals (Sweden)

Carl S Beckley

Full Text Available Tropical infectious disease prevalence is dependent on many socio-cultural determinants. However, rainfall and temperature frequently underlie overall prevalence, particularly for vector-borne diseases. As a result these diseases have increased prevalence in tropical as compared to temperate regions. Specific to tropical Africa, the tendency to incorrectly infer that tropical diseases are uniformly prevalent has been partially overcome with solid epidemiologic data. This finer resolution data is important in multiple contexts, including understanding risk, predictive value in disease diagnosis, and population immunity. We hypothesized that within the context of a tropical climate, vector-borne pathogen prevalence would significantly differ according to zonal differences in rainfall, temperature, relative humidity and vegetation condition. We then determined if these environmental data were predictive of pathogen prevalence. First we determined the prevalence of three major pathogens of cattle, Anaplasma marginale, Babesia bigemina and Theileria spp, in the three vegetation zones where cattle are predominantly raised in Ghana: Guinea savannah, semi-deciduous forest, and coastal savannah. The prevalence of A. marginale was 63%, 26% for Theileria spp and 2% for B. bigemina. A. marginale and Theileria spp. were significantly more prevalent in the coastal savannah as compared to either the Guinea savanna or the semi-deciduous forest, supporting acceptance of the first hypothesis. To test the predictive power of environmental variables, the data over a three year period were considered in best subsets multiple linear regression models predicting prevalence of each pathogen. Corrected Akaike Information Criteria (AICc were assigned to the alternative models to compare their utility. Competitive models for each response were averaged using AICc weights. Rainfall was most predictive of pathogen prevalence, and EVI also contributed to A. marginale and B

Real-Time Forecasting System of Winds, Waves and Surge in Tropical Cyclones

National Research Council Canada - National Science Library

Graber, Hans C; Donelan, Mark A; Brown, Michael G; Slinn, Donald N; Hagen, Scott C; Thompson, Donald R; Jensen, Robert E; Black, Peter G; Powell, Mark D; Guiney, John L; Cardone, Vincent J; Cox, Andrew T

2006-01-01

... of tropical cyclones The results of this forecasting system would provide real-time information to the National Hurricane Center during the tropical cyclone season in the Atlantic for establishing improved...

Piomiositis tuberculosa en un paciente inmunosuprimido

Directory of Open Access Journals (Sweden)

Johanna Osorio

2016-04-01

El caso que se presenta es llamativo dada la rareza de esta manifestación de la tuberculosis y la lenta mejoría con el tratamiento antituberculoso de primera línea en este paciente con infección por HIV y recaída, a pesar de que el aislamiento microbiológico resultó sensible.

Biomass expansion factors of Olea ferruginea (Royle) in sub tropical ...

African Journals Online (AJOL)

Wood biomass gives information about total productivity of the forest as well as individual tree. Olea ferruginea (Royle) which is small and evergreen is widely distributed in native sub tropical forests of Pakistan and extensively used as fuelwood domestically. This study was carried out in the sub tropical forests of Pakistan at ...

Tropical cyanobacterial blooms: a review of prevalence, problem taxa, toxins and influencing environmental factors

Directory of Open Access Journals (Sweden)

Maxine A.D. Mowe

2014-12-01

Full Text Available Toxic cyanobacterial blooms are a major issue in freshwater systems in many countries. The potentially toxic species and their ecological causes are likely to be different in tropical zones from those in temperate water bodies; however, studies on tropical toxic cyanobacterial blooms are sporadic and currently there is no global synthesis. In this review, we examined published information on tropical cyanobacterial bloom occurrence and toxin production to investigate patterns in their growth and distribution. Microcystis was the most frequently occurring bloom genus throughout tropical Asia, Africa and Central America, while Cylindrospermopsis and Anabaena blooms occurred in various locations in tropical Australia, America and Africa. Microcystis blooms were more prevalent during the wet season while Cylindrospermopsis blooms were more prevalent during the dry period. Microcystin was the most encountered toxin throughout the tropics. A meta-analysis of tropical cyanobacterial blooms showed that Microcystis blooms were more associated with higher total nitrogen concentrations, while Cylindrospermopsis blooms were more associated with higher maximum temperatures. Meta-analysis also showed a positive linear relationship between levels of microcystin and N:P (nitrate:phosphate ratio. Tropical African Microcystis blooms were found to have the lowest microcystin levels in relation to biomass and N:P (nitrate:phosphate compared to tropical Asian, Australian and American blooms. There was also no significant correlation between microcystin concentration and cell concentration for tropical African blooms as opposed to tropical Asian and American blooms. Our review illustrates that some cyanobacteria and toxins are more prevalent in tropical areas. While some tropical countries have considerable information regarding toxic blooms, others have few or no reported studies. 

Tropical sprue: case report with review of literature

Directory of Open Access Journals (Sweden)

W Robinson

2012-03-01

Full Text Available Tropical sprue is an important cause of malabsorption in adults and in children in South Asia. Investigations to exclude specific infective, immunological or inflammatory causes are important before considering tropical sprue as a diagnosis. Malabsorption disorders of the small intestine can be a source of great debilitation to the patient, and a diagnostic challenge to the pathologist. This article presents clinicopathological findings of a non coeliac tropical sprue in a 66–year-old male and discusses the histological and clinical information that can help differentiate coeliac from non coeliac sprue. DOI: http://dx.doi.org/10.3126/jpn.v2i3.6030 JPN 2012; 2(3: 241-244

Tropical Journal of Obstetrics and Gynaecology: Submissions

African Journals Online (AJOL)

... minimum printing cost of about 150 copies for authors and advertising organization ... Nonmembers: Please send change of address information to subscriptions@ ... The entire contents of the Tropical Journal of Obstetrics and Gynaecology ...

[Nutrition value of tropical and subtropical fruits].

Science.gov (United States)

Dubtsov, G G; Bessonov, V V; Baĭkov, V G; Makhova, N N; Sheviakova, L V; Bogachuk, M N; Baĭgarin, E K; Iao Bru, Lazar

2013-01-01

The article is devoted to the study of the chemical composition of tropical and subtropical fruit (avocado, papaya and mango), which are now in great numbers are on the appeared on the Russian market. Due to use technology tropical and subtropical fruits can be implemented in almost all areas and regions of the country. Relatively low cost makes these products quite popular among the people. In domestic scientific literature there are no systematic data describing the chemical composition of these tropical and subtropical fruits sold in the domestic market, while the information needed to calculate food and energy value of diets and culinary products derived from tropical and subtropical fruit. Avocado fruits are sources of insoluble dietary fiber content of which was equal to 12.2%, as well as minerals. The study of the fatty acid composition of lipids avocados showed high content of oleic acid fruit, which accounts for 53.2% of total fatty acids in these fruits. Which makes them a valuable source of unsaturated fatty acids.

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...

The persistent signature of tropical cyclones in ambient seismic noise

KAUST Repository

Gualtieri, Lucia; Camargo, Suzana J.; Pascale, Salvatore; Pons, Flavio M.E.; Ekströ m, Gö ran

2017-01-01

The spectrum of ambient seismic noise shows strong signals associated with tropical cyclones, yet a detailed understanding of these signals and the relationship between them and the storms is currently lacking. Through the analysis of more than a decade of seismic data recorded at several stations located in and adjacent to the northwest Pacific Ocean, here we show that there is a persistent and frequency-dependent signature of tropical cyclones in ambient seismic noise that depends on characteristics of the storm and on the detailed location of the station relative to the storm. An adaptive statistical model shows that the spectral amplitude of ambient seismic noise, and notably of the short-period secondary microseisms, has a strong relationship with tropical cyclone intensity and can be employed to extract information on the tropical cyclones.

The persistent signature of tropical cyclones in ambient seismic noise

KAUST Repository

Gualtieri, Lucia

2017-12-28

The spectrum of ambient seismic noise shows strong signals associated with tropical cyclones, yet a detailed understanding of these signals and the relationship between them and the storms is currently lacking. Through the analysis of more than a decade of seismic data recorded at several stations located in and adjacent to the northwest Pacific Ocean, here we show that there is a persistent and frequency-dependent signature of tropical cyclones in ambient seismic noise that depends on characteristics of the storm and on the detailed location of the station relative to the storm. An adaptive statistical model shows that the spectral amplitude of ambient seismic noise, and notably of the short-period secondary microseisms, has a strong relationship with tropical cyclone intensity and can be employed to extract information on the tropical cyclones.

[A text-book case of tropical facial elephantiasis].

Science.gov (United States)

Dilu, N-J; Sokolo, R

2007-02-01

Tropical facial elephantiasis is a nosological entity which can arise from various underlying causes: von Recklinghausen neurofibromatosis, lymphatic and cutaneodermal filarioses, deep mycosis. We report an exceptional case of tropical facial elephantiasis caused by onchocercosis and entomophtoromycosis (rhinophycomycosis). The patient's facial morphology was noted "hippopotamus-face" or "dog-face". Onchocercosis and entomophtoromycosis are two diseases known to cause facial elephantiasis. We have not however been able to find any case report in the literature of co-morbidity nor any information on factors predictive of concomitant occurrence.

Tropical Freshwater Biology

African Journals Online (AJOL)

Tropical Freshwater Biology promotes the publication of scientific contributions in the field of freshwater biology in the tropical and subtropical regions of the world. One issue is published annually but this number may be increased. Original research papers and short communications on any aspect of tropical freshwater ...

Successes and failures of small ruminant breeding programmes in the tropics: a review

NARCIS (Netherlands)

Kosgey, I.S.; Baker, R.L.; Udo, H.M.J.; Arendonk, van J.A.M.

2006-01-01

Despite the large numbers and importance of adapted indigenous sheep and goats in the tropics, information on sustainable conventional breeding programmes for them is scarce and often unavailable. This paper reviews within-breed selection strategies for indigenous small ruminants in the tropics,

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

Neglected tropical diseases

Directory of Open Access Journals (Sweden)

David Molyneux

2013-08-01

Full Text Available Seventeen neglected tropical diseases (NTDs have been identified by the World Health Organization (WHO. It is estimated that over 1 billion people are infected with NTDs, with a further 1 billion at risk. The majority of NTDs occur in the tropics and sub-tropics and have particular characteristics in common.

Tropical Rainforests.

Science.gov (United States)

Nigh, Ronald B.; Nations, James D.

1980-01-01

Presented is a summary of scientific knowledge about the rainforest environment, a tropical ecosystem in danger of extermination. Topics include the current state of tropical rainforests, the causes of rainforest destruction, and alternatives of rainforest destruction. (BT)

The design and application of a radiological consequence model for tropical and subtropical regions

International Nuclear Information System (INIS)

Domel, R.U.; Harris, F.F.; Crawford, J.

1998-01-01

The post Chernobyl era has seen the development of a plethora of radiological consequence models. The information used in these models pertains mostly to temperate and cold climate data, with these data mostly being hard-wired into the body of the model. At the Australian Nuclear Science and Technology Organisation (ANSTO), a model is being developed with a user-friendly interface which will assess the radiological consequences, after an incident, in tropical and sub-tropical climates. The model combines specific regional data (South East Asia) with transfer parameters (soil to plant, plant to animal) obtained for tropical and sub-tropical regions. Flexibility has been incorporated into the the design of the model to allow application in other regions. Where the relevant data are not available, default temperate data are used whilst specific research will be initiated to determine the information required. A Geographic Information System (GIS) is used for the display of input and output data allowing quick access to not only the results but also to the underlying assumptions

Some aspects of socio-economic determinants of mortality in tropical Africa.

Science.gov (United States)

Gaisie, S K

1980-01-01

Measurements of mortality levels and trends continue to be inadequate in Africa, largely because of the lack of reliable and adequate information on deaths. A series of estimates depicting mortality levels and trends has been prepared by demographers, different kinds of data and employing different estimation procedures, but knowledge of the "true" structure of mortality in tropical Africa is virtually nonexistent. Because of these problems only a "bird's eye view" of the prevailing situation in tropical Africa is presented. The discussion -- directed to mortality by sex and age, by residence, and by cause -- is based on secondary and fragmentary data. Socioeconomic and cultural determinants of mortality are also examined. Available information on male and female mortality indicates that the death rates for males are higher than they are for females. Early childhood mortality (1-4 years) in tropical Africa is relatively high compared with the other age groups, including infants. Mortality differentials have been noted among geographical and administrative units and subdivisions of populations within the various countries of tropical Africa. Also, urban dwellers enjoy a higher expectation of life at birth than do rural dwellers. Communicable diseases are the main killers in tropical Africa. Persistent poverty and malnutrition, poor housing, unhealthy conditions in the growing cities, nonexistence of health facilities in the rural areas, rapid population expansion, and low levels of education are among the factors impeding progress in reducing mortality in tropical Africa. The need exists to express development goals in terms of the progressive reduction and eventual elimination of malnutrition, disease, illiteracy, squalor, and inequalities. Future trends in mortality in tropical Africa may depend more than they have in the recent past on economic and social development.

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…

Tropical Agroecosystems: These habitats are misunderstood by the temperate zones, mismanaged by the tropics.

Science.gov (United States)

Janzen, D H

1973-12-21

require a great deal of pantropical information exchange. This information exchange will cost a great deal of resource, not only in travel funds and support of on-site study, but in insurance policies for the countries that are willing to take the risk of trying to change from an exploitative agroecosystem to an SYTA. For such an experiment to be sociologically successful, it will require a complete change in tropical educational systems, from emphasizing descriptions of events as they now stand, to emphasizing analysis of why things happen the way they do. This will also be very expensive, not only in retreading the technology and mind-sets of current teaching programs, but in gathering the facts on why the tropics have met their current fate. There is a surfeit of biological and agricultural reports dealing with ecological experiments and generalities which suggest that such and such will be the outcome if such and such form of resource harvest is attempted. It is clear that human desiderata regarding a particular site are often radically different from the needs of the "average" wild animals and plants that formed the basis for such experiments and generalities. A finely tuned SYTA will come close to providing a unique solution for each region. The generalities that will rule it are highly stochastic. The more tropical the region, the more evenly weighted the suboutcomes will be, and thus the more likely each region will be to have a unique overall outcome. For example, it is easy to imagine four different parts of the tropics, each with the same kind of soil and the same climate, with four different, successful SYTA's, one based on paddy rice, one on shelterwood forestry, one on tourism, and one on shifting maize culture. A regional experiment station working holistically toward an SYTA is potentially one of the best solutions available. As currently structured, however, almost all tropical experiment stations are inadequate for such a mission. Most commonly they are

Mapping tropical dry forest habitats integrating landsat NDVI, Ikonos imagery, and topographic information in the Caribbean island of Mona.

Science.gov (United States)

Martinuzzi, Sebastiáin; Gould, William A; Ramos Gonzalez, Olga M; Martinez Robles, Alma; Calle Maldonado, Paulina; Pérez-Buitrago, Néstor; Fumero Caban, José J

2008-06-01

Assessing the status of tropical dry forest habitats using remote sensing technologies is one of the research priorities for Neotropical forests. We developed a simple method for mapping vegetation and habitats in a tropical dry forest reserve, Mona Island, Puerto Rico, by integrating the Normalized Difference Vegetation Index (NDVI) from Landsat, topographic information, and high-resolution Ikonos imagery. The method was practical for identifying vegetation types in areas with a great variety of plant communities and complex relief, and can be adapted to other dry forest habitats of the Caribbean Islands. NDVI was useful for identifying the distribution of forests, woodlands, and shrubland, providing a natural representation of the vegetation patterns on the island. The use of Ikonos imagery allowed increasing the number of land cover classes. As a result, sixteen land-cover types were mapped over the 5500 ha area, with a kappa coefficient of accuracy equal to 79%. This map is a central piece for modeling vertebrate species distribution and biodiversity patterns by the Puerto Rico Gap Analysis Project, and it is of great value for assisting research and management actions in the island.

Energy Design Guidelines for High Performance Schools: Tropical Island Climates

Energy Technology Data Exchange (ETDEWEB)

2004-11-01

The Energy Design Guidelines for High Performance Schools--Tropical Island Climates provides school boards, administrators, and design staff with guidance to help them make informed decisions about energy and environmental issues important to school systems and communities. These design guidelines outline high performance principles for the new or retrofit design of your K-12 school in tropical island climates. By incorporating energy improvements into their construction or renovation plans, schools can significantly reduce energy consumption and costs.

Impacts of Particulate Matter on Gulf of Mexico Tropical Cyclones

Science.gov (United States)

Cao, W.; Rohli, R. V.

2017-12-01

The purpose of this project is to analyze the relationship between tropical cyclones of the Gulf of Mexico-Atlantic basin and fine particulate matter (PM2.5). The daily mean PM2.5 concentration values were collected from United States Environmental Protection Agency (EPA). Tropical cyclone data were collected from Tropical Prediction Center Best Track Reanalysis in Unisys Weather®. The GRIdded Binary (GRIB-formatted) data were downloaded from the Data Support Section of the Computational and Information Systems Laboratory at the National Center for Atmospheric Research (NCAR). Through ArcGIS®, the tropical cyclone tracks were compared with the interpolated daily mean PM2.5 concentration value. Results suggest that the tracks tend to avoid areas with higher PM2.5 concentrations, and the intensity was weakened significantly after passing the PM2.5-rich area. Through simulation using the Weather Research and Forecasting (WRF) model, the pressure and vertical structure of Hurricane Lili were weakened after passing the most PM2.5-rich area in Louisiana. Also, little evidence is found for the possibility of precipitation generated by the approaching tropical cyclone to cleanse the atmosphere of PM2.5 before storm passage. These results have important implications for tropical cyclone prediction as storms approach polluted areas or other places where PM2.5 particles are abundant, not only including urban environments but also in coastal areas where proscribed burns take place during tropical cyclone season, such as during sugarcane harvesting in southern Louisiana.

Cost-effectiveness of reducing emissions from tropical deforestation, 2016-2050

Science.gov (United States)

Busch, Jonah; Engelmann, Jens

2017-12-01

Reducing tropical deforestation is potentially a large-scale and low-cost strategy for mitigating climate change. Yet previous efforts to project the cost-effectiveness of policies to reduce greenhouse gas emissions from future deforestation across the tropics were hampered by crude available data on historical forest loss. Here we use recently available satellite-based maps of annual forest loss between 2001-2012, along with information on topography, accessibility, protected status, potential agricultural revenue, and an observed inverted-U-shaped relationship between forest cover loss and forest cover, to project tropical deforestation from 2016-2050 under alternative policy scenarios and to construct new marginal abatement cost curves for reducing emissions from tropical deforestation. We project that without new forest conservation policies 289 million hectares of tropical forest will be cleared from 2016-2050, releasing 169 GtCO2. A carbon price of US20/tCO2 (50/tCO2) across tropical countries would avoid 41 GtCO2 (77 GtCO2) from 2016-2050. By comparison, we estimate that Brazil’s restrictive policies in the Amazon between 2004-2012 successfully decoupled potential agricultural revenue from deforestation and reduced deforestation by 47% below what would have otherwise occurred, preventing the emission of 5.2 GtCO2. All tropical countries enacting restrictive anti-deforestation policies as effective as those in the Brazilian Amazon between 2004-2012 would avoid 58 GtCO2 from 2016-2050.

RAINBIO: a mega-database of tropical African vascular plants distributions

Directory of Open Access Journals (Sweden)

Dauby Gilles

2016-11-01

Full Text Available The tropical vegetation of Africa is characterized by high levels of species diversity but is undergoing important shifts in response to ongoing climate change and increasing anthropogenic pressures. Although our knowledge of plant species distribution patterns in the African tropics has been improving over the years, it remains limited. Here we present RAINBIO, a unique comprehensive mega-database of georeferenced records for vascular plants in continental tropical Africa. The geographic focus of the database is the region south of the Sahel and north of Southern Africa, and the majority of data originate from tropical forest regions. RAINBIO is a compilation of 13 datasets either publicly available or personal ones. Numerous in depth data quality checks, automatic and manual via several African flora experts, were undertaken for georeferencing, standardization of taxonomic names and identification and merging of duplicated records. The resulting RAINBIO data allows exploration and extraction of distribution data for 25,356 native tropical African vascular plant species, which represents ca. 89% of all known plant species in the area of interest. Habit information is also provided for 91% of these species.

Tropical Journal of Pharmaceutical Research: Editorial Policies

African Journals Online (AJOL)

The Tropical Journal of Pharmaceutical Research is an Open Access international ... Although primarily devoted to original research papers, the journal ... know so that we can keep the authors informed and, where necessary, find alternatives. ..... An example of how a search strategy should be presented can be seen in the ...

The deep human prehistory of global tropical forests and its relevance for modern conservation.

Science.gov (United States)

Roberts, Patrick; Hunt, Chris; Arroyo-Kalin, Manuel; Evans, Damian; Boivin, Nicole

2017-08-03

Significant human impacts on tropical forests have been considered the preserve of recent societies, linked to large-scale deforestation, extensive and intensive agriculture, resource mining, livestock grazing and urban settlement. Cumulative archaeological evidence now demonstrates, however, that Homo sapiens has actively manipulated tropical forest ecologies for at least 45,000 years. It is clear that these millennia of impacts need to be taken into account when studying and conserving tropical forest ecosystems today. Nevertheless, archaeology has so far provided only limited practical insight into contemporary human-tropical forest interactions. Here, we review significant archaeological evidence for the impacts of past hunter-gatherers, agriculturalists and urban settlements on global tropical forests. We compare the challenges faced, as well as the solutions adopted, by these groups with those confronting present-day societies, which also rely on tropical forests for a variety of ecosystem services. We emphasize archaeology's importance not only in promoting natural and cultural heritage in tropical forests, but also in taking an active role to inform modern conservation and policy-making.

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics: a systematic literature review.

NARCIS (Netherlands)

Hirve, S.; Lambach, P.; Paget, J.; Vandemaele, K.; Fitzner, J.; Zhang, W.

2016-01-01

Aim: The evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This paper reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries. Method: Global health databases were searched in three

Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics - a systematic literature review

NARCIS (Netherlands)

Hirve, S.; Lambach, P.; Paget, J.; Vandemaele, K.; Fitzner, J.; Zhang, W.

2016-01-01

AIM: The evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This article reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries. METHOD: Global health databases were searched in three

Tropical Peatland Geomorphology and Hydrology

Science.gov (United States)

Cobb, A.; Harvey, C. F.

2017-12-01

Tropical peatlands cover many low-lying areas in the tropics. In tropical peatlands, a feedback between hydrology, landscape morphology, and carbon storage causes waterlogged organic matter to accumulate into gently mounded land forms called peat domes over thousands of years. Peat domes have a stable morphology in which peat production is balanced by loss and net precipitation is balanced by lateral flow, creating a link between peatland morphology, rainfall patterns and drainage networks. We show how landscape morphology can be used to make inferences about hydrologic processes in tropical peatlands. In particular, we show that approaches using simple storage-discharge relationships for catchments are especially well suited to tropical peatlands, allowing river forecasting based on peatland morphology in catchments with tropical peatland subcatchments.

An Approach for Foliar Trait Retrieval from Airborne Imaging Spectroscopy of Tropical Forests

Directory of Open Access Journals (Sweden)

Roberta E. Martin

2018-01-01

Full Text Available Spatial information on forest functional composition is needed to inform management and conservation efforts, yet this information is lacking, particularly in tropical regions. Canopy foliar traits underpin the functional biodiversity of forests, and have been shown to be remotely measurable using airborne 350–2510 nm imaging spectrometers. We used newly acquired imaging spectroscopy data constrained with concurrent light detection and ranging (LiDAR measurements from the Carnegie Airborne Observatory (CAO, and field measurements, to test the performance of the Spectranomics approach for foliar trait retrieval. The method was previously developed in Neotropical forests, and was tested here in the humid tropical forests of Malaysian Borneo. Multiple foliar chemical traits, as well as leaf mass per area (LMA, were estimated with demonstrable precision and accuracy. The results were similar to those observed for Neotropical forests, suggesting a more general use of the Spectranomics approach for mapping canopy traits in tropical forests. Future mapping studies using this approach can advance scientific investigations and applications based on imaging spectroscopy.

The design and application of a radiological consequence model for tropical and subtropical regions

International Nuclear Information System (INIS)

Domel, R.U.; Harris, F.F.; Crawford, J.

1997-01-01

The post Chernobyl era has seen the development of a plethora of radiological consequence models. At ANSTO, a model is being developed with a user-friendly interface which will assess the radiological consequences, after an incident, in tropical and sub-tropical climates. The model combines specific regional dispersion and deposition data to determine the dose to man via the major pathways of external and internal irradiation. The external irradiation data will need to include lifestyle information such as time spent L indoors/outdoors, the high/low activity times of the different groups of people (especially critical groups) and shielding factors for housing. The internal irradiation data requires food consumption values, effect of food processing and transfer parameters (soil to plant, plant to animal) to be obtained for tropical and sub-tropical regions. The model allows the user to specify the radionuclide of interest, the age of the person receiving l the dose, race, dietary components and lifestyle. The operator may use a number of default categories, but regional information may also be entered and incorporated into the radiological model allowing assessment of dose to critical groups using site specific data. Initially, the model will deal with the South East Asian region but flexibility has been incorporated into the design to allow application in other regions. A geographic information system is used for display of all input and output data allowing quick access to not only the results but also the underlying assumptions. The model also has portability across computer platforms. The model has been developed to provide a tool for directing future research, has application as a planing tool for emergency response operations but its priority lies in understanding the behaviour of radionuclides in the tropical and sub-tropical environments and their effect on humankind

Tropical myeloneuropathies: the hidden endemias.

Science.gov (United States)

Román, G C; Spencer, P S; Schoenberg, B S

1985-08-01

Tropical myeloneuropathies include tropical ataxic neuropathy and tropical spastic paraparesis. These disorders occur in geographic isolates in several developing countries and are associated with malnutrition, cyanide intoxication from cassava consumption, tropical malabsorption (TM), vegetarian diets, and lathyrism. TM-malnutrition was a probable cause of myeloneuropathies among Far East prisoners of war in World War II. Clusters of unknown etiology occur in India, Africa, the Seychelles, several Caribbean islands, Jamaica, and Colombia. Treponemal infection (yaws) could be an etiologic factor in the last two. Tropical myeloneuropathies, a serious health problem, are multifactorial conditions that provide unsurpassed opportunities for international cooperation and neurologic research.

The Next-Generation Goddard Convective-Stratiform Heating Algorithm: New Retrievals for Tropical and Extra-tropical Environments

Science.gov (United States)

Lang, S. E.; Tao, W. K.; Iguchi, T.

2017-12-01

The Goddard Convective-Stratiform Heating (or CSH) algorithm has been used to estimate cloud heating over the global Tropics using TRMM rainfall data and a set of look-up-tables (LUTs) derived from a series of multi-week cloud-resolving model (CRM) simulations using the Goddard Cumulus Ensemble model (GCE). These simulations link satellite observables (i.e., surface rainfall and stratiform fraction) with cloud heating profiles, which are not directly observable. However, with the launch of GPM in 2014, the range over which such algorithms can be applied has been extended from the Tropics into higher latitudes, including cold season and synoptic weather systems. In response, the CSH algorithm and its LUTs have been revised both to improve the retrievals in the Tropics as well as expand retrievals to higher latitudes. For the Tropics, the GCE simulations used to build the LUTs were upgraded using larger 2D model domains (512 vs 256 km) and a new, improved Goddard 4-ice scheme as well as expanded with additional cases (4 land and 6 ocean in total). The new tropical LUTs are also re-built using additional metrics. Besides surface type, conditional rain intensity and stratiform fraction, the new LUTs incorporate echo top heights and low-level (0-2 km) vertical reflectivity gradients. CSH retrievals in the Tropics based on the new LUTs show significant differences from previous iterations using TRMM data or the old LUT metrics. For the Extra-tropics, 6 NU-WRF simulations of synoptic events (3 East Coast and 3 West Coast), including snow, were used to build new extra-tropical CSH LUTs. The LUT metrics for the extra-tropics are based on radar characteristics and freezing level height. The extra-tropical retrievals are evaluated with a self-consistency check approach using the model heating as `truth,' and freezing level height is used to transition CSH retrievals from the Tropics to Extra-tropics. Retrieved zonal average heating structures in the Extra-tropics are

Impact of deforestation on biomass burning in the tropics

International Nuclear Information System (INIS)

Hao, W.M.; Liu, M.H.; Ward, D.E.

1994-01-01

Fires are widely used for various land use practices in tropical countries. Large amounts of trace gases and aerosol particles are produced during the fires. It is important to assess the potential impact of these gases and particulate matter on the chemistry of the atmosphere and global climate. One of the largest uncertainties in quantifying the effects is the lack of information on the source strengths. The authors quantify the amount of biomass burned due to deforestation in each tropical country on basis of the deforestation rate, the above ground density, and the fraction of above ground biomass burned. Approximately 725 Tg of biomass were burned in 1980 and 984 Tg were burned in 1990. The 36% increase took place mostly in Latin America and tropical Asia. The largest source was Brazil, contributing about 29% of the total biomass burned in the tropics. The second largest source was Indonesia accounting for 10%, followed by Zaire accounting for about 8%. The burning of biomass due to increased deforestation has resulted in an additional 33 Tg CO and 2.5 Tg CH 4 emitted annually to the atmosphere from 1980 to 1990

Pneumonia in the tropics.

Science.gov (United States)

Lim, Tow Keang; Siow, Wen Ting

2018-01-01

Pneumonia in the tropics poses a heavy disease burden. The complex interplay of climate change, human migration influences and socio-economic factors lead to changing patterns of respiratory infections in tropical climate but also increasingly in temperate countries. Tropical and poorer countries, especially South East Asia, also bear the brunt of the global tuberculosis (TB) pandemic, accounting for almost one-third of the burden. But, as human migration patterns evolve, we expect to see more TB cases in higher income as well as temperate countries, and rise in infections like scrub typhus from ecotourism activities. Fuelled by the ease of air travel, novel zoonotic infections originating from the tropics have led to global respiratory pandemics. As such, clinicians worldwide should be aware of these new conditions as well as classical tropical bacterial pneumonias such as melioidosis. Rarer entities such as co-infections of leptospirosis and chikungunya or dengue will need careful consideration as well. In this review, we highlight aetiologies of pneumonia seen more commonly in the tropics compared with temperate regions, their disease burden, variable clinical presentations as well as impact on healthcare delivery. © 2017 Asian Pacific Society of Respirology.

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 ...

The relationships between precipitation, convective cloud and tropical cyclone intensity change

Science.gov (United States)

Ruan, Z.; Wu, Q.

2017-12-01

Using 16 years precipitation, brightness temperature (IR BT) data and tropical cyclone (TC) information, this study explores the relationship between precipitation, convective cloud and tropical cyclone (TC) intensity change in the Western North Pacific Ocean. It is found that TC intensity has positive relation with TC precipitation. TC precipitation increases with increased TC intensity. Based on the different phase of diurnal cycle, convective TC clouds were divided into very cold deep convective clouds (IR BTs<208K) and cold high clouds (208K

Tropical Cyclone Propagation

National Research Council Canada - National Science Library

Gray, William

1994-01-01

This paper discusses the question of tropical cyclone propagation or why the average tropical cyclone moves 1-2 m/s faster and usually 10-20 deg to the left of its surrounding (or 5-7 deg radius) deep layer (850-300 mb) steering current...

Neglected tropical diseases outside the tropics.

Directory of Open Access Journals (Sweden)

Francesca F Norman

Full Text Available BACKGROUND: The neglected tropical diseases (NTDs cause significant morbidity and mortality worldwide. Due to the growth in international travel and immigration, NTDs may be diagnosed in countries of the western world, but there has been no specific focus in the literature on imported NTDs. METHODS: Retrospective study of a cohort of immigrants and travelers diagnosed with one of the 13 core NTDs at a Tropical Medicine Referral Unit in Spain during the period April 1989-December 2007. Area of origin or travel was recorded and analyzed. RESULTS: There were 6168 patients (2634 immigrants, 3277 travelers and 257 VFR travelers in the cohort. NTDs occurred more frequently in immigrants, followed by VFR travelers and then by other travelers (p<0.001 for trend. The main NTDs diagnosed in immigrants were onchocerciasis (n = 240, 9.1% acquired mainly in sub-Saharan Africa, Chagas disease (n = 95, 3.6% in immigrants from South America, and ascariasis (n = 86, 3.3% found mainly in immigrants from sub-Saharan Africa. Most frequent NTDs in travelers were: schistosomiasis (n = 43, 1.3%, onchocerciasis (n = 17, 0.5% and ascariasis (n = 16, 0.5%, and all were mainly acquired in sub-Saharan Africa. The main NTDs diagnosed in VFR travelers were onchocerciasis (n = 14, 5.4%, and schistosomiasis (n = 2, 0.8%. CONCLUSIONS: The concept of imported NTDs is emerging as these infections acquire a more public profile. Specific issues such as the possibility of non-vectorial transmission outside endemic areas and how some eradication programmes in endemic countries may have an impact even in non-tropical western countries are addressed. Recognising NTDs even outside tropical settings would allow specific prevention and control measures to be implemented and may create unique opportunities for research in future.

Decadal trends of the upper ocean salinity in the tropical Indo-Pacific since mid-1990s.

Science.gov (United States)

Du, Yan; Zhang, Yuhong; Feng, Ming; Wang, Tianyu; Zhang, Ningning; Wijffels, Susan

2015-11-02

A contrasting trend pattern of sea surface salinity (SSS) between the western tropical Pacific (WTP) and the southeastern tropical Indian Ocean (SETIO) is observed during 2004-2013, with significant salinity increase in the WTP and freshening in the SETIO. In this study, we show that increased precipitation around the Maritime Continent (MC), decreased precipitation in the western-central tropical Pacific, and ocean advection processes contribute to the salinity trends in the region. From a longer historical record, these salinity trends started in the mid-1990s, a few years before the Global Warming Hiatus from 1998 to present. The salinity trends are associated a strengthening trend of the Walker Circulation over the tropical Indo-Pacific, which have reversed the long-term salinity changes in the tropical Indo-Pacific as a consequence of global warming. Understanding decadal variations of SSS in the tropical Indo-Pacific will better inform on how the tropical hydrological cycle will be affected by the natural variability and a warming climate.

Tropical Cyclogenesis in a Tropical Wave Critical Layer: Easterly Waves

Science.gov (United States)

Dunkerton, T. J.; Montgomery, M. T.; Wang, Z.

2009-01-01

The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside.

Current trends of tropical fruit waste utilization.

Science.gov (United States)

Cheok, Choon Yoong; Mohd Adzahan, Noranizan; Abdul Rahman, Russly; Zainal Abedin, Nur Hanani; Hussain, Norhayati; Sulaiman, Rabiha; Chong, Gun Hean

2018-02-11

Recent rapid growth of the world's population has increased food demands. This phenomenon poses a great challenge for food manufacturers in maximizing the existing food or plant resources. Nowadays, the recovery of health benefit bioactive compounds from fruit wastes is a research trend not only to help minimize the waste burden, but also to meet the intensive demand from the public for phenolic compounds which are believed to have protective effects against chronic diseases. This review is focused on polyphenolic compounds recovery from tropical fruit wastes and its current trend of utilization. The tropical fruit wastes include in discussion are durian (Durio zibethinus), mangosteen (Garcinia mangostana L.), rambutan (Nephelium lappaceum), mango (Mangifera indica L.), jackfruit (Artocarpus heterophyllus), papaya (Carica papaya), passion fruit (Passiflora edulis), dragon fruit (Hylocereus spp), and pineapple (Ananas comosus). Highlights of bioactive compounds in different parts of a tropical fruit are targeted primarily for food industries as pragmatic references to create novel innovative health enhancement food products. This information is intended to inspire further research ideas in areas that are still under-explored and for food processing manufacturers who would like to minimize wastes as the norm of present day industry (design) objective.

Computing Tropical Varieties

DEFF Research Database (Denmark)

Speyer, D.; Jensen, Anders Nedergaard; Bogart, T.

2005-01-01

The tropical variety of a d-dimensional prime ideal in a polynomial ring with complex coefficients is a pure d-dimensional polyhedral fan. This fan is shown to be connected in codimension one. We present algorithmic tools for computing the tropical variety, and we discuss our implementation...

Tropical varieties, maps and gossip

NARCIS (Netherlands)

Frenk, B.J.

2013-01-01

Tropical geometry is a relatively new field of mathematics that studies the tropicalization map: a map that assigns a certain type of polyhedral complex, called a tropical variety, to an embedded algebraic variety. In a sense, it translates algebraic geometric statements into combinatorial ones. An

Monitoring coastal wetlands in a highly dynamic tropical environment

International Nuclear Information System (INIS)

Saynor, M.J.; Finlayson, C.M.; Spiers, A.; Eliot, I.

2001-01-01

The Alligator Rivers Region in the wet-dry tropics of northern Australia has been selected by government and collaborating agencies as a key study area for the monitoring of natural and human-induced coastal change. The Region contains the floodplain wetlands of Kakadu National Park which have been recognised internationally for their natural and cultural heritage value. A coastal monitoring program for assessing and monitoring environmental change in the Alligator Rivers Region has been established at the Environmental Research Institute of the Supervising Scientist. This program has developed a regional capacity to measure and assess change on the wetlands, floodplains and coastline within the region. Field assessment and monitoring procedures have been developed for the program. The assessment procedures require use of georeferencing and data handling techniques to facilitate comparison and relational overlay of a wide variety of information. Monitoring includes regular survey of biophysical and cultural processes on the floodplains; such as the extension of tidal creeks and mangroves, shoreline movement, dieback in Melaleuca wetlands, and weed invasion of freshwater wetlands. A differential Global Positioning System is used to accurately georeference spatial data and a Geographic Information System is then used to store and assess information. The assessment and monitoring procedures can be applied to the wet-dry tropics in general. These studies are all particularly pertinent with the possibility of greenhouse gases causing global warming and potential sea-level rise, a major possible threat to the valued wetlands of Kakadu National Park, and across the wet-dry tropics in general

Pierre Ambroise-Thomas: a loyal friend and a strong supporter of tropical medicine in Brazil.

Science.gov (United States)

Daniel-Ribeiro, Cláudio Tadeu

2016-01-01

Our colleagues at the Sociedade Brasileira de Medicina Tropical have been informed of the demise of Professor Pierre Ambroise-Thomas (1937-2014). However, considering that the tribute we paid to him in 2015 - at the 20th anniversary of the Seminário Laveran & Deane sobre Malária - is equally true today, it is worth sharing it with the readers of the RSBMT, in recognition of his many virtues. Pierre Ambroise-Thomas (MD in 1963 and DSc in 1969) was Honorary Professor of Parasitology and Tropical Medicine at the Faculté de Médecine de Grenoble (France), Honorary President of the Académie Nationale de Médecine, member of the Académie Nationale de Pharmacie and Officier dans l'Ordre de La Légion d'Honneur. In addition to his important contributions to tropical medicine and parasitology, working in France during his long and productive career (50 years and 300 publications), Ambroise-Thomas became an admirer and supporter of Brazilian activities related to research, teaching and information in Tropical Medicine.

Pierre Ambroise-Thomas: a loyal friend and a strong supporter of tropical medicine in Brazil

Directory of Open Access Journals (Sweden)

Cláudio Tadeu Daniel-Ribeiro

Full Text Available Abstract: Our colleagues at the Sociedade Brasileira de Medicina Tropical have been informed of the demise of Professor Pierre Ambroise-Thomas (1937-2014. However, considering that the tribute we paid to him in 2015 - at the 20th anniversary of the Seminário Laveran & Deane sobre Malária - is equally true today, it is worth sharing it with the readers of the RSBMT, in recognition of his many virtues. Pierre Ambroise-Thomas (MD in 1963 and DSc in 1969 was Honorary Professor of Parasitology and Tropical Medicine at the Faculté de Médecine de Grenoble (France, Honorary President of the Académie Nationale de Médecine, member of the Académie Nationale de Pharmacie and Officier dans l'Ordre de La Légion d'Honneur. In addition to his important contributions to tropical medicine and parasitology, working in France during his long and productive career (50 years and 300 publications, Ambroise-Thomas became an admirer and supporter of Brazilian activities related to research, teaching and information in Tropical Medicine.

Particular characteristics of atopic eczema in tropical environments. The Tropical Environment Control for Chronic Eczema and Molecular Assessment (TECCEMA) cohort study.

Science.gov (United States)

Sánchez, Jorge; Sánchez, Andrés; Cardona, Ricardo

2017-01-01

Atopic dermatitis is a prevalent health problem in the world. Allergic sensitization is an important risk factor, but the roles of other factors, inherent in tropic region, are unknown. A cohort study was designed in a tropical city to investigate molecular and environmental risk factors for eczema, considering as particular features perennial exposure to mites, poor living conditions and others tropical characteristics. 433 patients were included at baseline and biological samples were collected during 24 months of follow-up. Clinical information was collected using questionnaires (SCORAD, DLQI and a subjective scale) during each clinical assessment. The prevalence of atopic eczema was 93%, with similar frequency between children and adults; parents history of eczema and polysensitization to mites, dogs, cats, cockroaches and birds, were risk factors for severe and persistent eczema and allergic comorbidities. Food sensitization was present in 16% of patients but food-induced allergies were scarce. Psychiatric, dental and ocular disorders were the most frequent non-allergic comorbidities. selection bias. We presented a tropical cohort of patients with eczema and we identified some risk factors for severe and persistent dermatitis. Some patterns of sensitization were associated with severe eczema and respiratory symptoms, and the natural history of "atopic march" is different to that described in some industrialized countries. The collection of biological samples will contribute to the understanding of the gene/environment interactions leading to allergy inception and evolution.

An economic assessment of tropical cyclone risk on offshore wind farms

DEFF Research Database (Denmark)

Hong, Lixuan; Möller, Bernd

2012-01-01

and cost and setting design parameters for offshore wind turbines are then discussed. The impact of tropical cyclones on offshore wind farms likes a double-edged sword, which might be advantageous for some regions in terms of increasing full-loaded hours of turbines, but also disadvantageous for others due....... A probabilistic tropical cyclone event model is applied to evaluate 20-year, 30-year, 50-year and 100-year recurrence of extreme wind speeds by geographical location. Combining a damage model derived from empirical loss data and an investment cost model within a Geographical Information System (GIS), the annual...... to its destructive effects. However, specific design standards and insurance of turbines would help reduce risks and economic losses of offshore wind farms in tropical cyclone-prone areas and expand exploitable locations for future offshore wind farms....

Interannual Weakening of the Tropical Pacific Walker Circulation Due to Strong Tropical Volcanism

Science.gov (United States)

Miao, Jiapeng; Wang, Tao; Wang, Huijun; Sun, Jianqi

2018-06-01

In order to examine the response of the tropical Pacific Walker circulation (PWC) to strong tropical volcanic eruptions (SVEs), we analyzed a three-member long-term simulation performed with HadCM3, and carried out four additional CAM4 experiments. We found that the PWC shows a significant interannual weakening after SVEs. The cooling effect from SVEs is able to cool the entire tropics. However, cooling over the Maritime Continent is stronger than that over the central-eastern tropical Pacific. Thus, non-uniform zonal temperature anomalies can be seen following SVEs. As a result, the sea level pressure gradient between the tropical Pacific and the Maritime Continent is reduced, which weakens trade winds over the tropical Pacific. Therefore, the PWC is weakened during this period. At the same time, due to the cooling subtropical and midlatitude Pacific, the Intertropical Convergence Zone (ITCZ) and South Pacific convergence zone (SPCZ) are weakened and shift to the equator. These changes also contribute to the weakened PWC. Meanwhile, through the positive Bjerknes feedback, weakened trade winds cause El Niño-like SST anomalies over the tropical Pacific, which in turn further influence the PWC. Therefore, the PWC significantly weakens after SVEs. The CAM4 experiments further confirm the influences from surface cooling over the Maritime Continent and subtropical/midlatitude Pacific on the PWC. Moreover, they indicate that the stronger cooling over the Maritime Continent plays a dominant role in weakening the PWC after SVEs. In the observations, a weakened PWC and a related El Niño-like SST pattern can be found following SVEs.

European cloth and "tropical" skin: clothing material and British ideas of health and hygiene in tropical climates.

Science.gov (United States)

Johnson, Ryan

2009-01-01

As Britain's imperial and colonial ambitions intensified toward the end of the nineteenth century, the preservation of white European health in tropical climates became an increasingly important concern. Since at least the seventeenth century, the "tropics" had been seen as spaces holding vast potential wealth but also death and disease. To combat these deadly but desirable landscapes, the British built a considerable commodity culture around the preservation of white European health, and for many, tropical clothing was one of the most important and essential items in their "kits." This article investigates the composition and use of such clothing in relation to British ideas of health and hygiene in tropical climates. First, it considers debates that ensued over the best material--wool, cotton, linen, silk, or a combination of these materials--and the role of "black" skin and local practice in the development of tropical clothing. Second, it demonstrates the importance of location in any discussion of tropical medicine and hygiene, and the tension and ambiguity that still surrounded British ideas of health and hygiene in the tropical colonies. Third, it argues that tropical clothing was important in the maintenance of climatic etiologies despite advances in parasitology and sanitary science. Finally, it considers the relationship of tropical clothing to the formation of a unique colonial identity. To British men and women embarking for any number of tropical destinations, proper clothing was not a banal and mundane component of their outfitting. For many, the clothing signified a departure from the safe and "civil" climes of Britain for adventure in the expanding tropical empire.

The Extratropical Transition of Tropical Storm Cindy From a GLM, ISS LIS and GPM Perspective

Science.gov (United States)

Heuscher, Lena; Gatlin, Patrick; Petersen, Walt; Liu, Chuntao; Cecil, Daniel J.

2017-01-01

The distribution of lightning with respect to tropical convective precipitation systems has been well established in previous studies and more recently by the successful Tropical Rainfall Measuring Mission (TRMM). However, TRMM did not provide information about precipitation features poleward of +/-38 deg latitude. Hence we focus on the evolution of lightning within extra-tropical cyclones traversing the mid-latitudes, especially its oceans. To facilitate such studies, lightning data from the Geostationary Lightning Mapper (GLM) onboard GOES-16 was combined with precipitation features obtained from the Global Precipitation Measurement (GPM) mission constellation of satellites.

Ecology of soil arthropod fauna in tropical forests: A review of studies from Puerto Rico

Science.gov (United States)

Grizelle Gonzalez; María F. Barberena

2017-01-01

The majority of ecological studies in the tropics deal with organisms participating in grazing food webs, while few deal with the diversity of invertebrates in the soil, leaf litter or dead wood that participate in detrital food webs. For tropical forests, the status of information on soil animal diversity is limited, especially when compared to other ecosystems such...

Real-Time Forecasting System of Winds, Waves and Surge in Tropical Cyclones

National Research Council Canada - National Science Library

Graber, Hans C; Donelan, Mark A; Brown, Michael G; Slinn, Donald N; Hagen, Scott C; Thompson, Donald R; Jensen, Robert E; Black, Peter G; Powell, Mark D; Guiney, John L

2004-01-01

.... The results of this forecasting system would provide real-time information to the National Hurricane Center during the tropical cyclone season in the Atlantic for establishing improved advisories...

Real-Time Forecasting System of Winds, Waves and Surge in Tropical Cyclones

National Research Council Canada - National Science Library

Graber, Hans C; Donelan, Mark A; Brown, Michael G; Slinn, Donald N; Hagen, Scott C; Thompson, Donald R; Jensen, Robert E; Black, Peter G; Powell, Mark D; Guiney, John L; Cardone, Vincent J; Cox, Andrew T; Augustus, Ellsworth H; Colonnese, Christopher P

2003-01-01

.... The results of this forecasting system would provide real-time information to the National Hurricane Center during the tropical cyclone season in the Atlantic for establishing improved advisories...

Real-Time Forecasting System of Winds, Waves and Surge in Tropical Cyclones

National Research Council Canada - National Science Library

Graber, Hans C; Donelan, Mark A; Brown, Michael G; Slinn, Donald N; Hagen, Scott C; Thompson, Donald R; Jensen, Robert E; Black, Peter G; Powell, Mark D; Guiney, John L

2005-01-01

.... The results of this forecasting system would provide real-time information to the National Hurricane Center during the tropical cyclone season in the Atlantic for establishing improved advisories...

FAQ HURRICANES, TYPHOONS, AND TROPICAL CYCLONES

Science.gov (United States)

? A6) What is a sub-tropical cyclone? A7) What is an extratropical cyclone ? A8) What is storm surge easterly wave and what causes them? A5) What is a tropical disturbance, tropical depression, tropical storm and how is it different from storm tide ? A9) What is a "CDO" ? A10) What is a TUTT ? A11

Mapping informal small-scale mining features in a data-sparse tropical environment with a small UAS

Science.gov (United States)

Chirico, Peter G.; Dewitt, Jessica D.

2017-01-01

This study evaluates the use of a small unmanned aerial system (UAS) to collect imagery over artisanal mining sites in West Africa. The purpose of this study is to consider how very high-resolution imagery and digital surface models (DSMs) derived from structure-from-motion (SfM) photogrammetric techniques from a small UAS can fill the gap in geospatial data collection between satellite imagery and data gathered during field work to map and monitor informal mining sites in tropical environments. The study compares both wide-angle and narrow field of view camera systems in the collection and analysis of high-resolution orthoimages and DSMs of artisanal mining pits. The results of the study indicate that UAS imagery and SfM photogrammetric techniques permit DSMs to be produced with a high degree of precision and relative accuracy, but highlight the challenges of mapping small artisanal mining pits in remote and data sparse terrain.

Propagation of dry tropical forest trees in Mexico

Science.gov (United States)

Martha A. Cervantes Sanchez

2002-01-01

There is a distinct lack of technical information on the propagation of native tree species from the dry tropical forest ecosystem in Mexico. This ecosystem has come under heavy human pressures to obtain several products such as specialty woods for fuel, posts for fences and construction, forage, edible fruits, stakes for horticulture crops, and medicinal products. The...

Proxies of Tropical Cyclone Isotope Spikes in Precipitation: Landfall Site Selection

Science.gov (United States)

Lawrence, J. R.; Maddocks, R.

2011-12-01

The human experience of climate change is not one of gradual changes in seasonal or yearly changes in temperature or rainfall. Despite that most paleoclimatic reconstructions attempt to provide just such information. Humans experience climate change on much shorter time scales. We remember hurricanes, weeks of drought or overwhelming rainy periods. Tropical cyclones produce very low isotope ratios in both rainfall and in atmospheric water vapor. Thus, climate proxies that potentially record these low isotope ratios offer the most concrete record of climate change to which humans can relate. The oxygen isotopic composition of tropical cyclone rainfall has the potential to be recorded in fresh water carbonate fossil material, cave deposits and corals. The hydrogen isotopic composition of tropical cyclone rainfall has the potential to be recorded in tree ring cellulose and organic matter in fresh water bodies. The Class of carbonate organisms known as Ostracoda form their carapaces very rapidly. Thus fresh water ephemeral ponds in the subtropics are ideal locations for isotopic studies because they commonly are totally dry when tropical cyclones make landfall. The other proxies suffer primarily from a dilution effect. The water from tropical cyclones is mixed with pre-existing water. In cave deposits tropical cyclone rains mix with soil and ground waters. In the near shore coral environment the rain mixes with seawater. For tree rings there are three sources of water: soil water, atmospheric water vapor that exchanges with leaf water and tropical cyclone rain. In lakes because of their large size rainfall runoff mixes with ground water and preexisting water in the lake. A region that shows considerable promise is Texas / Northeast Mexico. In a study of surface waters that developed from the passage of Tropical Storm Allison (2001) in SE Texas both the pond water and Ostracoda that bloomed recorded the low oxygen isotope signal of that storm (Lawrence et al, 2008). In

Isotopes in tropical agriculture

Energy Technology Data Exchange (ETDEWEB)

NONE

1962-04-15

Ways in which the use of radioisotopes and radiation can help to improve the agriculture of tropical Africa were discussed by a panel of experts. The panel included scientists from Africa, Europe, and the United States, most of whom had had actual experience dealing with agricultural problems in various parts of tropical Africa. The experts agreed that radioisotopes and radiation might now be employed to particular advantage in tropical Africa to improve crop nutrition and combat insect pests. Other applications discussed were in the fields of hydrology, plant breeding and food preservation

Isotopes in tropical agriculture

International Nuclear Information System (INIS)

1962-01-01

Ways in which the use of radioisotopes and radiation can help to improve the agriculture of tropical Africa were discussed by a panel of experts. The panel included scientists from Africa, Europe, and the United States, most of whom had had actual experience dealing with agricultural problems in various parts of tropical Africa. The experts agreed that radioisotopes and radiation might now be employed to particular advantage in tropical Africa to improve crop nutrition and combat insect pests. Other applications discussed were in the fields of hydrology, plant breeding and food preservation

Phytogeography of the tropical north-east African mountains

Directory of Open Access Journals (Sweden)

I. Friis

1983-11-01

Full Text Available The tropical north-east African mountains are tentatively divided into four phytochoria, the formal rank of which is not defined. The division is based on patterns of distribution and endemism in the region. The recognition of a distinct Afromontane phytochorion is now well established (Chapman & White, 1970; Werger, 1978; White, 1978. However, there is still very little information on the phytogeography of the individual mountains or mountain systems. This study hopes to fill a little of the gap by analysing distribution patterns and patterns of endemism in the flora of the tropical north-east African mountains. The north-east African mountain system is the largest in tropical Africa (see e.g. map in White, 1978. At the core of this system is the large Ethiopian massif, around which are located various mountains and mountain chains. These include the Red Sea Hills in the Sudan, the mountain chain in northern Somalia, the south-west Arabian mountains, and the Imatong mountains of south-east Sudan. The latter are often referred to the East African mountain system (White, 1978 but. as I will point out later, they also have a close connection with the south-west highlands of Ethiopia. The paper presents some results of my study of the mountain flora of tropical north-east Africa, particularly the forest species. Where no source is indicated, the data are from my own unpublished studies.

Spatio-temporal dynamics of the tropical rain forest

Energy Technology Data Exchange (ETDEWEB)

Chave, J. [CEN Saclay, Gif-sur-Yvette (France). Service de Physique de l' Etat Condense

2000-07-01

Mechanisms which drive the dynamics of forest ecosystems are complex, from seedling establishment to pollination, and seed dispersal by animals, running water or wind. These processes are more complex when the ecosystem shelters a large number of species and of vegetative forms, as it is the case in the tropical rainforest. To take them into account, we must develop and use models. I present a review of the fundamental mechanisms for the of a natural forest dynamics - photosynthesis, tree growth, recruitment and mortality - as well as a description of the past and of the present of tropical rainforests. This information is used to develop a spatially-explicit and individual-based forest model. Simplified models are deduced from it, and they serve to address more specific issues, such as the resilience of the forest to climate disturbances, or savanna-forest dynamics. The last topic is related to the spatio-temporal description of tropical plant biodiversity. A detailed introduction to the problem is provided, and models accounting for the maintenance of diversity are compared. These models include non spatial as well a spatial approaches (branching anihilating random walks and voter model with mutation). (orig.)

Global economic trade-offs between wild nature and tropical agriculture.

Science.gov (United States)

Carrasco, Luis R; Webb, Edward L; Symes, William S; Koh, Lian P; Sodhi, Navjot S

2017-07-01

Global demands for agricultural and forestry products provide economic incentives for deforestation across the tropics. Much of this deforestation occurs with a lack of information on the spatial distribution of benefits and costs of deforestation. To inform global sustainable land-use policies, we combine geographic information systems (GIS) with a meta-analysis of ecosystem services (ES) studies to perform a spatially explicit analysis of the trade-offs between agricultural benefits, carbon emissions, and losses of multiple ecosystem services because of tropical deforestation from 2000 to 2012. Even though the value of ecosystem services presents large inherent uncertainties, we find a pattern supporting the argument that the externalities of destroying tropical forests are greater than the current direct economic benefits derived from agriculture in all cases bar one: when yield and rent potentials of high-value crops could be realized in the future. Our analysis identifies the Atlantic Forest, areas around the Gulf of Guinea, and Thailand as areas where agricultural conversion appears economically efficient, indicating a major impediment to the long-term financial sustainability of Reducing Emissions from Deforestation and forest Degradation (REDD+) schemes in those countries. By contrast, Latin America, insular Southeast Asia, and Madagascar present areas with low agricultural rents (ARs) and high values in carbon stocks and ES, suggesting that they are economically viable conservation targets. Our study helps identify optimal areas for conservation and agriculture together with their associated uncertainties, which could enhance the efficiency and sustainability of pantropical land-use policies and help direct future research efforts.

Particular characteristics of atopic eczema in tropical environments. The Tropical Environment Control for Chronic Eczema and Molecular Assessment (TECCEMA) cohort study*

Science.gov (United States)

Sánchez, Jorge; Sánchez, Andrés; Cardona, Ricardo

2017-01-01

Background Atopic dermatitis is a prevalent health problem in the world. Allergic sensitization is an important risk factor, but the roles of other factors, inherent in tropic region, are unknown. Objective A cohort study was designed in a tropical city to investigate molecular and environmental risk factors for eczema, considering as particular features perennial exposure to mites, poor living conditions and others tropical characteristics. Methods 433 patients were included at baseline and biological samples were collected during 24 months of follow-up. Clinical information was collected using questionnaires (SCORAD, DLQI and a subjective scale) during each clinical assessment. Results The prevalence of atopic eczema was 93%, with similar frequency between children and adults; parents history of eczema and polysensitization to mites, dogs, cats, cockroaches and birds, were risk factors for severe and persistent eczema and allergic comorbidities. Food sensitization was present in 16% of patients but food-induced allergies were scarce. Psychiatric, dental and ocular disorders were the most frequent non-allergic comorbidities. Study limitations selection bias. Conclusion We presented a tropical cohort of patients with eczema and we identified some risk factors for severe and persistent dermatitis. Some patterns of sensitization were associated with severe eczema and respiratory symptoms, and the natural history of "atopic march" is different to that described in some industrialized countries. The collection of biological samples will contribute to the understanding of the gene/environment interactions leading to allergy inception and evolution. PMID:28538875

Tropical cyclogenesis in a tropical wave critical layer: easterly waves

Directory of Open Access Journals (Sweden)

T. J. Dunkerton

2009-08-01

Full Text Available The development of tropical depressions within tropical waves over the Atlantic and eastern Pacific is usually preceded by a "surface low along the wave" as if to suggest a hybrid wave-vortex structure in which flow streamlines not only undulate with the waves, but form a closed circulation in the lower troposphere surrounding the low. This structure, equatorward of the easterly jet axis, is identified herein as the familiar critical layer of waves in shear flow, a flow configuration which arguably provides the simplest conceptual framework for tropical cyclogenesis resulting from tropical waves, their interaction with the mean flow, and with diabatic processes associated with deep moist convection. The recirculating Kelvin cat's eye within the critical layer represents a sweet spot for tropical cyclogenesis in which a proto-vortex may form and grow within its parent wave. A common location for storm development is given by the intersection of the wave's critical latitude and trough axis at the center of the cat's eye, with analyzed vorticity centroid nearby. The wave and vortex live together for a time, and initially propagate at approximately the same speed. In most cases this coupled propagation continues for a few days after a tropical depression is identified. For easterly waves, as the name suggests, the propagation is westward. It is shown that in order to visualize optimally the associated Lagrangian motions, one should view the flow streamlines, or stream function, in a frame of reference translating horizontally with the phase propagation of the parent wave. In this co-moving frame, streamlines are approximately equivalent to particle trajectories. The closed circulation is quasi-stationary, and a dividing streamline separates air within the cat's eye from air outside. The critical layer equatorward of the easterly jet axis is important to tropical cyclogenesis because its cat's eye provides (i a region of

Challenge and opportunities of space-based precipitation radar for spatio-temporal hydrology analysis in tropical maritime influenced catchment: Case study on the hilly tropical watershed of Peninsular Malaysia

International Nuclear Information System (INIS)

Mahmud, M R; Numata, S; Matsuyama, H; Hashim, M; Hosaka, T

2014-01-01

This paper highlights two critical issues regarding hilly watershed in Peninsular Malaysia; (1) current status of spatio-temporal condition of rain gauge based measurement, and (2) potential of space-based precipitation radar to study the rainfall dynamics. Two analyses were carried out represent each issue consecutively. First, the spatial distribution and efficiency of rain gauge in hilly watershed Peninsular Malaysia is evaluated with respect to the land use and elevation information using Geographical Information System (GIS) approach. Second, the spatial pattern of rainfall changes is analysed using the Tropical Rainfall Measuring Mission (TRMM) satellite information. The spatial analysis revealed that the rain gauge distribution had sparse coverage on hilly watershed and possessed inadequate efficiency for effective spatial based assessment. Significant monthly rainfall changes identified by TRMM satellite on the upper part of the watershed had occurred occasionally in 1999, 2000, 2001, 2006, and 2009 went undetected by conventional rain gauge. This study informed the potential and opportunities of space-based precipitation radar to fill the gaps of knowledge on spatio-temporal rainfall patterns for hydrology and related fields in tropical region

Forest extent and deforestation in tropical Africa since 1900.

Science.gov (United States)

Aleman, Julie C; Jarzyna, Marta A; Staver, A Carla

2018-01-01

Accurate estimates of historical forest extent and associated deforestation rates are crucial for quantifying tropical carbon cycles and formulating conservation policy. In Africa, data-driven estimates of historical closed-canopy forest extent and deforestation at the continental scale are lacking, and existing modelled estimates diverge substantially. Here, we synthesize available palaeo-proxies and historical maps to reconstruct forest extent in tropical Africa around 1900, when European colonization accelerated markedly, and compare these historical estimates with modern forest extent to estimate deforestation. We find that forests were less extensive in 1900 than bioclimatic models predict. Resultantly, across tropical Africa, ~ 21.7% of forests have been deforested, yielding substantially slower deforestation than previous estimates (35-55%). However, deforestation was heterogeneous: West and East African forests have undergone almost complete decline (~ 83.3 and 93.0%, respectively), while Central African forests have expanded at the expense of savannahs (~ 1.4% net forest expansion, with ~ 135,270 km 2 of savannahs encroached). These results suggest that climate alone does not determine savannah and forest distributions and that many savannahs hitherto considered to be degraded forests are instead relatively old. These data-driven reconstructions of historical biome distributions will inform tropical carbon cycle estimates, carbon mitigation initiatives and conservation planning in both forest and savannah systems.

Sensitivity of South American tropical climate to Last Glacial Maximum boundary conditions: focus on teleconnections with tropics and extratropics (Invited)

Science.gov (United States)

Khodri, M.; Kageyama, M.; Roche, D. M.

2009-12-01

Proxy data over tropical latitudes for the Last Glacial Maximum (LGM) has been interpreted as a southward shift of the Inter Tropical Convergence Zone (ITCZ) and so far linked to a mechanism analogous to the modern day “meridional-mode” in the Atlantic Ocean. Here we have explored alternative mechanisms, related to the direct impact of the LGM global changes in the dry static stability on tropical moist deep convection. We have used a coupled ocean-atmosphere model capable of capturing the thermodynamical structure of the atmosphere and the tropical component of the Hadley and Walker circulations. In each experiment, we have applied either all the LGM forcings, or the individual contributions of greenhouse gases (GHG) concentrations, ice sheet topography and/or albedo to explore the hydrological response over tropical latitudes with a focus on South America. The dominant forcing for the LGM tropical temperature and precipitation changes is found to be due to the reduced GHG, through the direct effect of reduced radiative heating (Clausius-Clapeyron relationship). The LGM GHG is also responsible for increased extra-tropical static stability which strengthens the Hadley Cell. Stronger subsidence over northern tropics then produces an amplification of the northern tropics drying initially due to the direct cooling effect. The land ice sheet is also able to promote the Hadley cell feedback mostly via the topographic effect on the extra-tropical dry static stability and on the position of the subtropical jets. Our results therefore suggest that the communication between the extratropics and the tropics is tighter during LGM and does not necessarily rely on the “meridional-mode” mechanism. The Hadley cell response is constrained by the requirement that diabatic heating in the tropics balances cooling in subtropics. We show that such extratropics-tropics dependence is stronger at the LGM because of the stronger perturbation of northern extra tropical thermal and

How can we conserve intact tropical peatlands?

Science.gov (United States)

Lawson, Ian; Roucoux, Katherine

2017-04-01

The scientific community has, for more than three decades, been expressing increasing alarm about the fate of peatlands in parts of Indonesia and Malaysia, where extensive land-use conversion and drainage for rice and oil palm have greatly compromised peatland hydrology, ecology, biological richness, and carbon storage. The discourse in the literature on these peatlands is now moving on from attempts to preserve the last remaining fragments of peat-swamp forest, towards discussion of how best to restore damaged ecosystems, and whether it is possible to manage plantations more 'sustainably'. It is becoming increasingly clear, however, that peatlands occur quite widely in other parts of the lowland tropics, including parts of Amazonia and the Congo Basin, and many of these peatlands can reasonably be described as 'intact': although few if any parts of the tropics are totally unaffected by human actions, the hydrology and functional ecology of these systems appear to be close to a 'natural' state. The question then arises as to what should be done with the knowledge of their existence. Here we analyse the arguments in favour of protecting intact peatlands, and the potential conflicts with other priorities such as economic development and social justice. We evaluate alternative mechanisms for protecting intact peatlands, focusing on the particular issues raised by peatlands as opposed to other kinds of tropical ecosystem. We identify ways in which natural science agendas can help to inform these arguments, using our own contributions in palaeoecology and carbon mapping as examples. Finally, we argue for a radical reconsideration of research agendas in tropical peatlands, highlighting the potential contribution of methodologies borrowed from the social sciences and humanities.

Salinity fronts in the tropical Pacific Ocean.

Science.gov (United States)

Kao, Hsun-Ying; Lagerloef, Gary S E

2015-02-01

This study delineates the salinity fronts (SF) across the tropical Pacific, and describes their variability and regional dynamical significance using Aquarius satellite observations. From the monthly maps of the SF, we find that the SF in the tropical Pacific are (1) usually observed around the boundaries of the fresh pool under the intertropical convergence zone (ITCZ), (2) stronger in boreal autumn than in other seasons, and (3) usually stronger in the eastern Pacific than in the western Pacific. The relationship between the SF and the precipitation and the surface velocity are also discussed. We further present detailed analysis of the SF in three key tropical Pacific regions. Extending zonally around the ITCZ, where the temperature is nearly homogeneous, we find the strong SF of 1.2 psu from 7° to 11°N to be the main contributor of the horizontal density difference of 0.8 kg/m 3 . In the eastern Pacific, we observe a southward extension of the SF in the boreal spring that could be driven by both precipitation and horizontal advection. In the western Pacific, the importance of these newly resolved SF associated with the western Pacific warm/fresh pool and El Niño southern oscillations are also discussed in the context of prior literature. The main conclusions of this study are that (a) Aquarius satellite salinity measurements reveal the heretofore unknown proliferation, structure, and variability of surface salinity fronts, and that (b) the fine-scale structures of the SF in the tropical Pacific yield important new information on the regional air-sea interaction and the upper ocean dynamics.

Life Cycle of Tropical Convection and Anvil in Observations and Models

Science.gov (United States)

McFarlane, S. A.; Hagos, S. M.; Comstock, J. M.

2011-12-01

Tropical convective clouds are important elements of the hydrological cycle and produce extensive cirrus anvils that strongly affect the tropical radiative energy balance. To improve simulations of the global water and energy cycles and accurately predict both precipitation and cloud radiative feedbacks, models need to realistically simulate the lifecycle of tropical convection, including the formation and radiative properties of ice anvil clouds. By combining remote sensing datasets from precipitation and cloud radars at the Atmospheric Radiation Measurement (ARM) Darwin site with geostationary satellite data, we can develop observational understanding of the lifetime of convective systems and the links between the properties of convective systems and their associated anvil clouds. The relationships between convection and anvil in model simulations can then be compared to those seen in the observations to identify areas for improvement in the model simulations. We identify and track tropical convective systems in the Tropical Western Pacific using geostationary satellite observations. We present statistics of the tropical convective systems including size, age, and intensity and classify the lifecycle stage of each system as developing, mature, or dissipating. For systems that cross over the ARM Darwin site, information on convective intensity and anvil properties are obtained from the C-Pol precipitation radar and MMCR cloud radar, respectively, and are examined as a function of the system lifecycle. Initial results from applying the convective identification and tracking algorithm to a tropical simulation from the Weather Research and Forecasting (WRF) model run show that the model produces reasonable overall statistics of convective systems, but details of the life cycle (such as diurnal cycle, system tracks) differ from the observations. Further work will focus on the role of atmospheric temperature and moisture profiles in the model's convective life cycle.

Possible climatic impact of tropical deforestation

Energy Technology Data Exchange (ETDEWEB)

Potter, G L; Ellsaesser, H W; MacCracken, M C; Luther, F M

1975-12-25

A computer model of climate changes resulting from removal of tropical rain forests to increase arable acreage is described. A chain of consequences is deduced from the model which begins with deforestation and ends with overall global cooling and a reduction in precipitation. A model of the global water budget shows that the reduction in precipitation is accompanied by cooling in the upper tropical troposphere, a lowering of the tropical tropopause, and a warming of the lower tropical stratosphere. (HLW)

Large rainfall changes consistently projected over substantial areas of tropical land

Science.gov (United States)

Chadwick, Robin; Good, Peter; Martin, Gill; Rowell, David P.

2016-02-01

Many tropical countries are exceptionally vulnerable to changes in rainfall patterns, with floods or droughts often severely affecting human life and health, food and water supplies, ecosystems and infrastructure. There is widespread disagreement among climate model projections of how and where rainfall will change over tropical land at the regional scales relevant to impacts, with different models predicting the position of current tropical wet and dry regions to shift in different ways. Here we show that despite uncertainty in the location of future rainfall shifts, climate models consistently project that large rainfall changes will occur for a considerable proportion of tropical land over the twenty-first century. The area of semi-arid land affected by large changes under a higher emissions scenario is likely to be greater than during even the most extreme regional wet or dry periods of the twentieth century, such as the Sahel drought of the late 1960s to 1990s. Substantial changes are projected to occur by mid-century--earlier than previously expected--and to intensify in line with global temperature rise. Therefore, current climate projections contain quantitative, decision-relevant information on future regional rainfall changes, particularly with regard to climate change mitigation policy.

Volatile sulfur compounds in tropical fruits

Directory of Open Access Journals (Sweden)

Robert J. Cannon

2018-04-01

Full Text Available Global production and demand for tropical fruits continues to grow each year as consumers are enticed by the exotic flavors and potential health benefits that these fruits possess. Volatile sulfur compounds (VSCs are often responsible for the juicy, fresh aroma of tropical fruits. This poses a challenge for analytical chemists to identify these compounds as most often VSCs are found at low concentrations in most tropical fruits. The aim of this review is to discuss the extraction methods, enrichment techniques, and instrumentation utilized to identify and quantify VSCs in natural products. This will be followed by a discussion of the VSCs reported in tropical and subtropical fruits, with particular attention to the odor and taste attributes of each compound. Finally, the biogenesis and enzymatic formation of specific VSCs in tropical fruits will be highlighted along with the contribution each possesses to the aroma of their respective fruit. Keywords: Tropical fruits, Volatile sulfur compounds, Extraction methods

[Tropical sprue (author's transl)].

Science.gov (United States)

Gras, C; Chapoy, P; Aubry, P

1981-01-01

Tropical sprue is a disease of the small intestine characterized by a malabsorption syndrome with a subtotal or partial mucosal atrophy. It is observed in Asia and Central America. It appears to be rare in Africa but its real frequency is unknown as small bowel biopsys are not routinely done. Bacterial overgrowth as well as giardiasis may be trigger factors of the disease the pathogenesis of which is still incompletely understood. The disease beginning as chronic diarrhea is later on characterized by an aphtoïd stomatitis and a macrocytic anemia. Treatment with antibiotics and folic acid is efficient and has a diagnostic value. If treatment is started lately, vitamin B 12 is then also necessary. In any intestinal syndrome observed in tropical areas without an ascertained etiologic diagnosis, peroral biopsie of the small intestine is requested. However, with the use of pediatric endoscope it will be possible to appreciate the respective incidence of tropical sprue and asymptomatic tropical sprue in Africa South of the Sahara.

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...

Covariability of Central America/Mexico winter precipitation and tropical sea surface temperatures

Science.gov (United States)

Pan, Yutong; Zeng, Ning; Mariotti, Annarita; Wang, Hui; Kumar, Arun; Sánchez, René Lobato; Jha, Bhaskar

2018-06-01

In this study, the relationships between Central America/Mexico (CAM) winter precipitation and tropical Pacific/Atlantic sea surface temperatures (SSTs) are examined based on 68-year (1948-2015) observations and 59-year (1957-2015) atmospheric model simulations forced by observed SSTs. The covariability of the winter precipitation and SSTs is quantified using the singular value decomposition (SVD) method with observational data. The first SVD mode relates out-of-phase precipitation anomalies in northern Mexico and Central America to the tropical Pacific El Niño/La Niña SST variation. The second mode links a decreasing trend in the precipitation over Central America to the warming of SSTs in the tropical Atlantic, as well as in the tropical western Pacific and the tropical Indian Ocean. The first mode represents 67% of the covariance between the two fields, indicating a strong association between CAM winter precipitation and El Niño/La Niña, whereas the second mode represents 20% of the covariance. The two modes account for 32% of CAM winter precipitation variance, of which, 17% is related to the El Niño/La Niña SST and 15% is related to the SST warming trend. The atmospheric circulation patterns, including 500-hPa height and low-level winds obtained by linear regressions against the SVD SST time series, are dynamically consistent with the precipitation anomaly patterns. The model simulations driven by the observed SSTs suggest that these precipitation anomalies are likely a response to tropical SST forcing. It is also shown that there is significant potential predictability of CAM winter precipitation given tropical SST information.

Huracanes y biodiversidad costera tropical

Directory of Open Access Journals (Sweden)

Sergio I Salazar-Vallejo

2002-06-01

Full Text Available La biodiversidad costera tropical ha sido modulada por las tormentas y huracanes durante mucho tiempo y en nuestros días también está sujeta a severas presiones por actividades antropogénicas. El objetivo de esta revisión fue el compilar la información disponible para mejorar nuestra comprensión sobre el impacto de los huracanes y tratar de incentivar el establecimiento de monitoreos de los cambios del paisaje costero, ya que es la mejor forma de evaluar los impactos de estas tormentas. Aunque el impacto de los ciclones resiste generalizaciones amplias, se incluyen aspectos sobre dinámica histórica y asociación con eventos temporales y se detallan los efectos por resuspensión y traslado de sedimentos, impacto del oleaje y fragmentación de organismos del arrecife coralino. También se presentan brevemente algunos efectos sobre tortugas marinas y bosques costerosTropical coastal biodiversity has been modulated by tropical storms during a long time and it is currently facing a heavy human impact. The purpose of this review is to compile the available information to improve our understanding of hurricane impacts and to promote the establishment of coastal landscape monitoring, because that is the best way to assess these impacts. Although generalizations on hurricane effects are elusive, some historical dynamics and temporal relationships are included and some details are presented on the impacts by resuspension and movement of sediments, storm waves, and breaking off of coral reef organisms. Some effects on marine turtles and coastal forests are also briefly pointed out

Coherent tropical Indo-Pacific interannual climate variability

OpenAIRE

Wieners, C.E.; de Ruijter, W.P.M.; Ridderinkhof, W.; von der Heydt, A.S.; Dijkstra, H.A.

2016-01-01

A multichannel singular spectrum analysis (MSSA) applied simultaneously to tropical sea surface temperature (SST), zonal wind, and burstiness (zonal wind variability) reveals three significant oscillatory modes. They all show a strong ENSO signal in the eastern Pacific Ocean (PO) but also a substantial SST signal in the western Indian Ocean (IO). A correlation-based analysis shows that the western IO signal contains linearly independent information on ENSO. Of the three Indo-Pacific ENSO mode...

Training on Eastern Pacific tropical cyclones for Latin American students

Science.gov (United States)

Farfán, L. M.; Raga, G. B.

2009-05-01

Tropical cyclones are one of the most impressive atmospheric phenomena and their development in the Atlantic and Eastern Pacific basins has potential to affect several Latin-American and Caribbean countries, where human resources are limited. As part of an international research project, we are offering short courses based on the current understanding of tropical cyclones in the Eastern Pacific basin. Our main goal is to train students from higher-education institutions from various countries in Latin America. Key aspects are tropical cyclone formation and evolution, with particular emphasis on their development off the west coast of Mexico. Our approach includes lectures on tropical cyclone climatology and formation, dynamic and thermodynamic models, air-sea interaction and oceanic response, ocean waves and coastal impacts as well as variability and climate-related predictions. In particular, we use a best-track dataset issued by the United States National Hurricane Center and satellite observations to analyze convective patterns for the period 1970-2006. Case studies that resulted in landfall over northwestern Mexico are analyzed in more detail; this includes systems that developed during the 2006, 2007 and 2008 seasons. Additionally, we have organized a human-dimensions symposium to discuss socio-economic issues that are associated with the landfall of tropical cyclones. This includes coastal zone impact and flooding, the link between cyclones and water resources, the flow of weather and climate information from scientists to policy- makers, the role of emergency managers and decision makers, impact over health issues and the viewpoint of the insurance industry.

Pan-tropical monitoring of deforestation

International Nuclear Information System (INIS)

Achard, F; DeFries, R; Eva, H; Hansen, M; Mayaux, P; Stibig, H-J

2007-01-01

This paper reviews the technical capabilities for monitoring deforestation from a pan-tropical perspective in response to the United Nations Framework Convention on Climate Change (UNFCCC) process, which is studying the technical issues surrounding the ability to reduce greenhouse gas emissions from deforestation in developing countries. The successful implementation of such policies requires effective forest monitoring systems that are reproducible, provide consistent results, meet standards for mapping accuracy, and can be implemented from national to pan-tropical levels. Remotely sensed data, supported by ground observations, are crucial to such efforts. Recent developments in global to regional monitoring of forests can contribute to reducing the uncertainties in estimates of emissions from deforestation. Monitoring systems at national levels in developing countries can also benefit from pan-tropical and regional observations, mainly by identifying hot spots of change and prioritizing areas for monitoring at finer spatial scales. A pan-tropical perspective is also required to ensure consistency between different national monitoring systems. Data sources already exist to determine baseline periods in the 1990s as historical reference points. Key requirements for implementing such monitoring programs, both at pan-tropical and at national scales, are international commitment of resources to increase capacity, coordination of observations to ensure pan-tropical coverage, access to free or low-cost data, and standardized, consensus protocols for data interpretation and analysis

Spatiotemporal analysis of tropical disease research combining Europe PMC and affiliation mapping web services.

Science.gov (United States)

Palmblad, Magnus; Torvik, Vetle I

2017-01-01

Tropical medicine appeared as a distinct sub-discipline in the late nineteenth century, during a period of rapid European colonial expansion in Africa and Asia. After a dramatic drop after World War II, research on tropical diseases have received more attention and research funding in the twenty-first century. We used Apache Taverna to integrate Europe PMC and MapAffil web services, containing the spatiotemporal analysis workflow from a list of PubMed queries to a list of publication years and author affiliations geoparsed to latitudes and longitudes. The results could then be visualized in the Quantum Geographic Information System (QGIS). Our workflows automatically matched 253,277 affiliations to geographical coordinates for the first authors of 379,728 papers on tropical diseases in a single execution. The bibliometric analyses show how research output in tropical diseases follow major historical shifts in the twentieth century and renewed interest in and funding for tropical disease research in the twenty-first century. They show the effects of disease outbreaks, WHO eradication programs, vaccine developments, wars, refugee migrations, and peace treaties. Literature search and geoparsing web services can be combined in scientific workflows performing a complete spatiotemporal bibliometric analyses of research in tropical medicine. The workflows and datasets are freely available and can be used to reproduce or refine the analyses and test specific hypotheses or look into particular diseases or geographic regions. This work exceeds all previously published bibliometric analyses on tropical diseases in both scale and spatiotemporal range.

Extracted atmospheric impairments on earth-sky signal quality in tropical regions at Ku-band

Science.gov (United States)

Al-Saegh, Ali Mohammed; Sali, Aduwati; Mandeep, J. S.; Ismail, Alyani

2013-11-01

Atmospheric condition variations were shown to have a major effect on the earth sky signal quality at Ku band. Moreover, such variations increased in the tropical regions as compared to temperate areas due to their different weather parameters. With the increase of recent satellite communication technology applications throughout the tropical countries and lack of information regarding the atmospheric impairments analysis, simulation and mitigation techniques, there is an ever increasing need for extracting a unique and accurate performance of the signal quality effects during highly natural tropical weather impairments. This paper presents a new method developed for proper analysis with distinctive and highly realistic performance evaluation for signal quality during the atmospheric conditions variations in 14 tropical areas from the four continents analyzed based on actual measured parameters. The method implementation includes signal attenuation, carrier to noise ratio, symbol energy to noise ratio, and symbol error rate at different areas and different modulation schemes. Furthermore, for improvement in analysis in terms of covering more remarkable regions in tropics, the paper provides new measurements data with analysis for certain region in tropics used as a test bed and to add measurement data of such area to the world's data base for future researchers. The results show a significant investigation and performance observation in terms of weather impairments in tropical regions in general and each region in that area in particular regarding the signal attenuation and error rates accompanied for several transmission schemes.

Parvalbumin--the major tropical fish allergen.

Science.gov (United States)

Lim, Dawn Li-Chern; Neo, Keng Hwee; Yi, Fong Cheng; Chua, Kaw Yan; Goh, Denise Li-Meng; Shek, Lynette Pei-Chi; Giam, Yoke Chin; Van Bever, Hugo P S; Lee, Bee Wah

2008-08-01

Fish allergy is common in countries where consumption is high. Asian nations are amongst the world's largest consumers of fish but the allergen profiles of tropical fish are unknown. This study sought to evaluate the allergenicity of four commonly consumed tropical fish, the threadfin (Polynemus indicus), Indian anchovy (Stolephorus indicus), pomfret (Pampus chinensis) and tengirri (Scomberomorus guttatus). Immunoglobulin E (IgE) cross-reactivity with parvalbumin of cod fish (Gad c 1), the major fish allergen, was also studied. Detection of tropical fish and cod specific-IgE was performed by UniCap assay, and skin prick tests were also carried out. The IgE-binding components of tropical fish were identified using IgE immunoblot techniques, and cross-reactivity with Gad c 1 was assessed by ELISA inhibition and IgE immunoblot inhibition. Clinically, nine of 10 patients studied were allergic to multiple fish. All patients exhibited detectable specific-IgE to cod fish (10 of 10 skin prick test positive, eight of 10 UniCap assay positive) despite lack of previous exposure. The major allergen of the four tropical fish was the 12-kDa parvalbumin. IgE cross-reactivity of these allergens to Gad c 1 was observed to be moderate to high in the tropical fish studied. Parvalbumins are the major allergens in commonly consumed tropical fish. They are cross-reactive with each other as well as with Gad c 1. Commercial tests for cod fish appear to be sufficient for the detection of tropical fish specific-IgE.

Life in the clouds: are tropical montane cloud forests responding to changes in climate?

Science.gov (United States)

Hu, Jia; Riveros-Iregui, Diego A

2016-04-01

The humid tropics represent only one example of the many places worldwide where anthropogenic disturbance and climate change are quickly affecting the feedbacks between water and trees. In this article, we address the need for a more long-term perspective on the effects of climate change on tropical montane cloud forests (TMCF) in order to fully assess the combined vulnerability and long-term response of tropical trees to changes in precipitation regimes, including cloud immersion. We first review the ecophysiological benefits that cloud water interception offers to trees in TMCF and then examine current climatological evidence that suggests changes in cloud base height and impending changes in cloud immersion for TMCF. Finally, we propose an experimental approach to examine the long-term dynamics of tropical trees in TMCF in response to environmental conditions on decade-to-century time scales. This information is important to assess the vulnerability and long-term response of TMCF to changes in cloud cover and fog frequency and duration.

1997 Annual Tropical Cyclone Report

National Research Council Canada - National Science Library

Dillon, C

1997-01-01

.... Separate bulletins are issued for the Western Pacific and the Indian Ocean. TROPICAL CYCLONE FORMATION ALERT - Defines a specific area when synoptic, satellite, or other germane data indicate development of a significant tropical cyclone (TC...

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.

Scenarios in tropical forest degradation: carbon stock trajectories for REDD+

Directory of Open Access Journals (Sweden)

Rafael B. de Andrade

2017-03-01

Full Text Available Abstract Background Human-caused disturbance to tropical rainforests—such as logging and fire—causes substantial losses of carbon stocks. This is a critical issue to be addressed in the context of policy discussions to implement REDD+. This work reviews current scientific knowledge about the temporal dynamics of degradation-induced carbon emissions to describe common patterns of emissions from logging and fire across tropical forest regions. Using best available information, we: (i develop short-term emissions factors (per area for logging and fire degradation scenarios in tropical forests; and (ii describe the temporal pattern of degradation emissions and recovery trajectory post logging and fire disturbance. Results Average emissions from aboveground biomass were 19.9 MgC/ha for logging and 46.0 MgC/ha for fire disturbance, with an average period of study of 3.22 and 2.15 years post-disturbance, respectively. Longer-term studies of post-logging forest recovery suggest that biomass accumulates to pre-disturbance levels within a few decades. Very few studies exist on longer-term (>10 years effects of fire disturbance in tropical rainforests, and recovery patterns over time are unknown. Conclusions This review will aid in understanding whether degradation emissions are a substantial component of country-level emissions portfolios, or whether these emissions would be offset by forest recovery and regeneration.

Tropical Rainfall Measuring Mission (TRMM) and the Future of Rainfall Estimation from Space

Science.gov (United States)

Kakar, Ramesh; Adler, Robert; Smith, Eric; Starr, David OC. (Technical Monitor)

2001-01-01

Tropical rainfall is important in the hydrological cycle and to the lives and welfare of humans. Three-fourths of the energy that drives the atmospheric wind circulation comes from the latent heat released by tropical precipitation. Recognizing the importance of rain in the tropics, NASA for the U.S.A. and NASDA for Japan have partnered in the design, construction and flight of a satellite mission to measure tropical rainfall and calculate the associated latent heat release. The Tropical Rainfall Measuring Mission (TRMM) satellite was launched on November 27, 1997, and data from all the instruments first became available approximately 30 days after launch. Since then, much progress has been made in the calibration of the sensors, the improvement of the rainfall algorithms and applications of these results to areas such as Data Assimilation and model initialization. TRMM has reduced the uncertainty of climatological rainfall in tropics by over a factor of two, therefore establishing a standard for comparison with previous data sets and climatologies. It has documented the diurnal variation of precipitation over the oceans, showing a distinct early morning peak and this satellite mission has shown the utility of precipitation information for the improvement of numerical weather forecasts and climate modeling. This paper discusses some promising applications using TRMM data and introduces a measurement concept being discussed by NASA/NASDA and ESA for the future of rainfall estimation from space.

Teleconnections of the tropical Atlantic to the tropical Indian and Pacific Oceans. A review of recent findings

Energy Technology Data Exchange (ETDEWEB)

Wang Chunzai [NOAA Atlantic Oceanographic and Meteorological Lab., Miami, FL (United States); Kucharski, Fred; Barimalala, Rondrotiana [The Abdus Salam International Centre for Theoretical Physics, Earth System Physics, Section Trieste (Italy); Bracco, Annalisa [School of Earth and Atmospheric Sciences Georgia, Inst. of Tech., Atlanta, GA (United States)

2009-08-15

Recent studies found that tropical Atlantic variability may affect the climate in both the tropical Pacific and Indian Ocean basins, possibly modulating the Indian summer monsoon and Pacific ENSO events. A warm tropical Atlantic Ocean forces a Gill-Matsuno-type quadrupole response with a low-level anticyclone located over India that weakens the Indian monsoon circulation, and vice versa for a cold tropical Atlantic Ocean. The tropical Atlantic Ocean can also induce changes in the Indian Ocean sea surface temperatures (SSTs). especially along the coast of Africa and in the western side of the Indian basin. Additionally, it can influence the tropical Pacific Ocean via an atmospheric teleconnection that is associated with the Atlantic Walker circulation. Although the Pacific El Nino does not contemporaneously correlate with the Atlantic Nino, anomalous warming or cooling of the two equatorial oceans can form an inter-basin SST gradient that induces surface zonal wind anomalies over equatorial South America and other regions in both ocean basins. The zonal wind anomalies act as a bridge linking the two ocean basins, and in turn reinforce the inter-basin SST gradient through the atmospheric Walker circulation and oceanic processes. Thus, a positive feedback seems to exist for climate variability of the tropical Pacific-Atlantic Oceans and atmospheric system, in which the inter-basin SST gradient is coupled to the overlying atmospheric wind. (orig.)

Ocean barrier layers' effect on tropical cyclone intensification.

Science.gov (United States)

Balaguru, Karthik; Chang, Ping; Saravanan, R; Leung, L Ruby; Xu, Zhao; Li, Mingkui; Hsieh, Jen-Shan

2012-09-04

Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are "quasi-permanent" features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.

Mycorrhizas and tropical soil fertility

NARCIS (Netherlands)

Cardoso, I.M.; Kuyper, T.W.

2006-01-01

Major factors that constrain tropical soil fertility and sustainable agriculture are low nutrient capital, moisture stress, erosion, high P fixation, high acidity with aluminium toxicity, and low soil biodiversity. The fragility of many tropical soils limits food production in annual cropping

Current status of tropical fruit breeding and genetics for three tropical fruit species cultivated in Japan: pineapple, mango, and papaya

Science.gov (United States)

Ogata, Tatsushi; Yamanaka, Shinsuke; Shoda, Moriyuki; Urasaki, Naoya; Yamamoto, Toshiya

2016-01-01

Tropical fruit crops are predominantly produced in tropical and subtropical developing countries, but some are now grown in southern Japan. Pineapple (Ananas comosus), mango (Mangifera indica) and papaya (Carica papaya) are major tropical fruits cultivated in Japan. Modern, well-organized breeding systems have not yet been developed for most tropical fruit species. Most parts of Japan are in the temperate climate zone, but some southern areas such as the Ryukyu Islands, which stretch from Kyushu to Taiwan, are at the northern limits for tropical fruit production without artificial heating. In this review, we describe the current status of tropical fruit breeding, genetics, genomics, and biotechnology of three main tropical fruits (pineapple, mango, and papaya) that are cultivated and consumed in Japan. More than ten new elite cultivars of pineapple have been released with improved fruit quality and suitability for consumption as fresh fruit. New challenges and perspectives for obtaining high fruit quality are discussed in the context of breeding programs for pineapple. PMID:27069392

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.

Maize, tropical (Zea mays L.).

Science.gov (United States)

Assem, Shireen K

2015-01-01

Maize (Zea mays L.) is the third most important food crop globally after wheat and rice. In sub-Saharan Africa, tropical maize has traditionally been the main staple of the diet; 95 % of the maize grown is consumed directly as human food and as an important source of income for the resource-poor rural population. The biotechnological approach to engineer biotic and abiotic traits implies the availability of an efficient plant transformation method. The production of genetically transformed plants depends both on the ability to integrate foreign genes into target cells and the efficiency with which plants are regenerated. Maize transformation and regeneration through immature embryo culture is the most efficient system to regenerate normal transgenic plants. However, this system is highly genotype dependent. Genotypes adapted to tropic areas are difficult to regenerate. Therefore, transformation methods used with model genotypes adapted to temperate areas are not necessarily efficient with tropical lines. Agrobacterium-mediated transformation is the method of choice since it has been first achieved in 1996. In this report, we describe a transformation method used successfully with several tropical maize lines. All the steps of transformation and regeneration are described in details. This protocol can be used with a wide variety of tropical lines. However, some modifications may be needed with recalcitrant lines.

Annually resolved ice core records of tropical climate variability over the past ~1800 years.

Science.gov (United States)

Thompson, L G; Mosley-Thompson, E; Davis, M E; Zagorodnov, V S; Howat, I M; Mikhalenko, V N; Lin, P-N

2013-05-24

Ice cores from low latitudes can provide a wealth of unique information about past climate in the tropics, but they are difficult to recover and few exist. Here, we report annually resolved ice core records from the Quelccaya ice cap (5670 meters above sea level) in Peru that extend back ~1800 years and provide a high-resolution record of climate variability there. Oxygen isotopic ratios (δ(18)O) are linked to sea surface temperatures in the tropical eastern Pacific, whereas concentrations of ammonium and nitrate document the dominant role played by the migration of the Intertropical Convergence Zone in the region of the tropical Andes. Quelccaya continues to retreat and thin. Radiocarbon dates on wetland plants exposed along its retreating margins indicate that it has not been smaller for at least six millennia.

MST radar and polarization lidar observations of tropical cirrus

Directory of Open Access Journals (Sweden)

Y. Bhavani Kumar

2001-08-01

these levels. The analysis of simultaneous lidar and MST Radar observations can thus yield valuable information on the structure and dynamics of the cirrus, specifically near the boundaries of such clouds.Key words. Atmospheric composition and structure (cloud physics and chemistry; instruments and technique - Meteorology and atmospheric dynamics (tropical meteorology

MST radar and polarization lidar observations of tropical cirrus

Directory of Open Access Journals (Sweden)

Y. Bhavani Kumar

these levels. The analysis of simultaneous lidar and MST Radar observations can thus yield valuable information on the structure and dynamics of the cirrus, specifically near the boundaries of such clouds.

Key words. Atmospheric composition and structure (cloud physics and chemistry; instruments and technique - Meteorology and atmospheric dynamics (tropical meteorology

Small-scale variability in tropical tropopause layer humidity

Science.gov (United States)

Jensen, E. J.; Ueyama, R.; Pfister, L.; Karcher, B.; Podglajen, A.; Diskin, G. S.; DiGangi, J. P.; Thornberry, T. D.; Rollins, A. W.; Bui, T. V.; Woods, S.; Lawson, P.

2016-12-01

Recent advances in statistical parameterizations of cirrus cloud processes for use in global models are highlighting the need for information about small-scale fluctuations in upper tropospheric humidity and the physical processes that control the humidity variability. To address these issues, we have analyzed high-resolution airborne water vapor measurements obtained in the Airborne Tropical TRopopause EXperiment over the tropical Pacific between 14 and 20 km. Using accurate and precise 1-Hz water vapor measurements along approximately-level aircraft flight legs, we calculate structure functions spanning horizontal scales ranging from about 0.2 to 50 km, and we compare the water vapor variability in the lower (about 14 km) and upper (16-19 km) Tropical Tropopause Layer (TTL). We also compare the magnitudes and scales of variability inside TTL cirrus versus in clear-sky regions. The measurements show that in the upper TTL, water vapor concentration variance is stronger inside cirrus than in clear-sky regions. Using simulations of TTL cirrus formation, we show that small variability in clear-sky humidity is amplified by the strong sensitivity of ice nucleation rate to supersaturation, which results in highly-structured clouds that subsequently drive variability in the water vapor field. In the lower TTL, humidity variability is correlated with recent detrainment from deep convection. The structure functions indicate approximately power-law scaling with spectral slopes ranging from about -5/3 to -2.

Tropical rain forest: a wider perspective

National Research Council Canada - National Science Library

Goldsmith, F. B

1998-01-01

.... Barbier -- Can non-market values save the tropical forests? / D. Pearce -- The role of policy and institutions / James Mayers and Stephen Bass -- Modelling tropical land use change and deforestation...

What was tropical about tropical neurasthenia? The utility of the diagnosis in the management of British East Africa.

Science.gov (United States)

Crozier, Anna

2009-10-01

During the first quarter of the twentieth century, tropical neurasthenia was a popular diagnosis for a nervous condition experienced by Europeans in the topics. Tropical neurasthenia was not psychosis or madness, but was rather an ennui or loss of "edge" brought about by the strains of tropical life, especially the unfamiliar, hot climate. A catch-all for a wide range of symptoms, many missionaries, colonial staff, and settlers throughout Empire were repatriated because of it, although this article concentrates on Colonial Service employees working in British East Africa. While histories of tropical neurasthenia have usefully (and correctly) explained this diagnosis as an expression of the anxieties of the colonial regime, this article adds a new dimension to the historiography by arguing that tropical neurasthenia can only be properly understood as a hybrid form, dependent not only upon the peculiarities of the colonial situation, but also descended from British and American clinical understandings of neurasthenia. Moreover, once tropical neurasthenia is properly acknowledged as being typical of clinical understandings of the time, other reasons for its comparatively long endurance in the colonial situation emerge. This article shows that tropical neurasthenia remained a popular diagnosis in East Africa not only because (as historians have argued previously) it dovetailed with prevalent ideas of colonial acclimatization, but also because it was a practically useful tool in the management and regulation of colonial personnel.

Palaeoecology of testate amoebae in a tropical peatland.

Science.gov (United States)

Swindles, Graeme T; Lamentowicz, Mariusz; Reczuga, Monika; Galloway, Jennifer M

2016-09-01

We present the first detailed analysis of subfossil testate amoebae from a tropical peatland. Testate amoebae were analysed in a 4-m peat core from western Amazonia (Peru) and a transfer function developed from the site was applied to reconstruct changes in water table over the past ca. 8,000 years. Testate amoebae were in very low abundance in the core, especially in the lower 125cm, due to a combination of poor preservation and obscuration by other organic matter. A modified preparation method enabled at least 50 testate amoebae to be counted in each core sample. The most abundant taxa preserved include Centropyxis aculeata, Hyalosphenia subflava, Phryganella acropodia and Trigonopyxis arcula. Centropyxis aculeata, an unambiguous wet indicator, is variably present and indicates several phases of near-surface water table. Our work shows that even degraded, low-abundance assemblages of testate amoebae can provide useful information regarding the long-term ecohydrological developmental history of tropical peatlands. Copyright © 2015 Elsevier GmbH. All rights reserved.

Archives: Tropical Journal of Pharmaceutical Research

African Journals Online (AJOL)

Items 1 - 50 of 97 ... Archives: Tropical Journal of Pharmaceutical Research. Journal Home > Archives: Tropical Journal of Pharmaceutical Research. Log in or Register to get access to full text downloads.

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....

[Profile of tropical diseases in Portugal].

Science.gov (United States)

Ventura, F A

1996-01-01

The increased incidence of Imported Tropical Diseases in Portugal is correlated to a recent higher standard of living, influence of media and a consequent expansion of tourism, and above all to the close relationship existing between Portugal and Africa. The number and pathology (parasitic diarrhoeas, protozoal and helminthic infections) of in-patients with Tropical Diseases at the Unidade de Doenças Infecciosas, Parasitárias e de Medicina Tropical (UDIP-MT) were described, with special emphasis on Malaria (155 in-patients during the period from 1989 to 1993) and on Sleeping Sickness, where Eflornitin (DFMO) was for the first time used in Portugal. Finally, the impact of HIV epidemic on incidence and different clinical presentations of parasitic and other tropical pathology was also evaluated.

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

Tropical Africa: Land use, biomass, and carbon estimates for 1980

Energy Technology Data Exchange (ETDEWEB)

Brown, S. [Environmental Protection Agency, Corvallis, OR (United States). Western Ecology Division; Gaston, G. [Environmental Protection Agency, Corvallis, OR (United States). National Research Council; Daniels, R.C. [ed.] [Oak Ridge National Lab., TN (United States)

1996-06-01

This document describes the contents of a digital database containing maximum potential aboveground biomass, land use, and estimated biomass and carbon data for 1980 and describes a methodology that may be used to extend this data set to 1990 and beyond based on population and land cover data. The biomass data and carbon estimates are for woody vegetation in Tropical Africa. These data were collected to reduce the uncertainty associated with the possible magnitude of historical releases of carbon from land use change. Tropical Africa is defined here as encompassing 22.7 x 10{sup 6} km{sup 2} of the earth`s land surface and includes those countries that for the most part are located in Tropical Africa. Countries bordering the Mediterranean Sea and in southern Africa (i.e., Egypt, Libya, Tunisia, Algeria, Morocco, South Africa, Lesotho, Swaziland, and Western Sahara) have maximum potential biomass and land cover information but do not have biomass or carbon estimate. The database was developed using the GRID module in the ARC/INFO{sup TM} geographic information system. Source data were obtained from the Food and Agriculture Organization (FAO), the U.S. National Geophysical Data Center, and a limited number of biomass-carbon density case studies. These data were used to derive the maximum potential and actual (ca. 1980) aboveground biomass-carbon values at regional and country levels. The land-use data provided were derived from a vegetation map originally produced for the FAO by the International Institute of Vegetation Mapping, Toulouse, France.

Objective Tracking of Tropical Cyclones in the North-West Pacific Basin Based on Wind Field Information only

Science.gov (United States)

Leckebusch, G. C.; Befort, D. J.; Kruschke, T.

2016-12-01

Although only ca. 12% of the global insured losses of natural disasters occurred in Asia, there are two major reasons to be concerned about risks in Asia: a) The fraction of loss events was substantial higher with 39% of which 94% were due to atmospheric processes; b) Asia and especially China, is undergoing quick transitions and especially the insurance market is rapidly growing. In order to allow for the estimation of potential future (loss) impacts in East-Asia, in this study we further developed and applied a feature tracking system based on extreme wind speed occurrences to tropical cyclones, which was originally developed for extra-tropical cyclones (Leckebusch et al., 2008). In principle, wind fields will be identified and tracked once a coherent exceedance of local percentile thresholds is identified. The focus on severe wind impact will allow an objective link between the strength of a cyclone and its potential damages over land. The wind tracking is developed in such a way to be applicable also to course-gridded AOGCM simulation. In the presented configuration the wind tracking algorithm is applied to the Japanese reanalysis (JRA55) and TC Identification is based on 850hPa wind speeds (6h resolution) from 1979 to 2014 over the Western North Pacific region. For validation the IBTrACS Best Track archive version v03r8 is used. Out of all 904 observed tracks, about 62% can be matched to at least one windstorm event identified in JRA55. It is found that the relative amount of matched best tracks increases with the maximum intensity. Thus, a positive matching (hit rate) of above 98% for Violent Typhoons (VTY), above 90% for Very Strong Typhoons (VSTY), about 75% for Typhoons (TY), and still some 50% for less intense TCs (TD, TS, STS) is found. This result is extremely encouraging to apply this technique to AOGCM outputs and to derive information about affected regions and intensity-frequency distributions potentially changed under future climate conditions.

[Tropical chronic pancreatitis in a young patient].

Science.gov (United States)

Reyes, J; Ginard, D; Barranco, L; Riera, J; Obrador, A

2001-11-01

Tropical chronic pancreatitis is a form of idiopathic chronic pancreatitis that has not previously been described in Spain. Typically it is related to dietary factors and malnutrition, although genetic factors may also play a significant role in the development of the disease. We report a case of chronic tropical pancreatitis in a 27-year-old woman from the Dominican Republic domiciled in Spain since 1992. The patient was admitted to our hospital for acute pancreatitis that fulfilled the diagnostic criteria (clinical and radiological) for chronic tropical pancreatitis. This case has led us to review this uncommon entity. Because of the increasing number of immigrants from tropical countries, chronic tropical pancreatitis will probably need to be taken into account in the differential diagnosis of chronic pancreatitis in our patients.

Diverging responses of tropical Andean biomes under future climate conditions.

Directory of Open Access Journals (Sweden)

Carolina Tovar

Full Text Available Observations and projections for mountain regions show a strong tendency towards upslope displacement of their biomes under future climate conditions. Because of their climatic and topographic heterogeneity, a more complex response is expected for biodiversity hotspots such as tropical mountain regions. This study analyzes potential changes in the distribution of biomes in the Tropical Andes and identifies target areas for conservation. Biome distribution models were developed using logistic regressions. These models were then coupled to an ensemble of 8 global climate models to project future distribution of the Andean biomes and their uncertainties. We analysed projected changes in extent and elevational range and identified regions most prone to change. Our results show a heterogeneous response to climate change. Although the wetter biomes exhibit an upslope displacement of both the upper and the lower boundaries as expected, most dry biomes tend to show downslope expansion. Despite important losses being projected for several biomes, projections suggest that between 74.8% and 83.1% of the current total Tropical Andes will remain stable, depending on the emission scenario and time horizon. Between 3.3% and 7.6% of the study area is projected to change, mostly towards an increase in vertical structure. For the remaining area (13.1%-17.4%, there is no agreement between model projections. These results challenge the common believe that climate change will lead to an upslope displacement of biome boundaries in mountain regions. Instead, our models project diverging responses, including downslope expansion and large areas projected to remain stable. Lastly, a significant part of the area expected to change is already affected by land use changes, which has important implications for management. This, and the inclusion of a comprehensive uncertainty analysis, will help to inform conservation strategies in the Tropical Andes, and to guide similar

PLOS Neglected Tropical Diseases: Ten years of progress in neglected tropical disease control and elimination … More or less.

Directory of Open Access Journals (Sweden)

Peter Hotez

2017-04-01

Full Text Available This year PLOS Neglected Tropical Diseases (PLOS NTDs celebrates its tenth anniversary following the publication of the first issue in 2007 [1]. When PLOS NTDs was founded, the framework of the neglected tropical diseases (NTDs as an alternative to "other diseases" (as they were then referred to in the Millennium Development Goals was just getting started-especially for Africa [2, 3]. In the decade since, PLOS NTDs has overseen enormous successes in NTD control and elimination. Here, we want to briefly review the ten year progress made towards the control or elimination of the diseases now identified by the WHO as NTDs. Many of the details are highlighted in PLOS NTDs papers cited here, but the summary information is based on the recently released Global Burden of Disease (GBD Study 2015 (also launched with Gates Foundation support that summarized past-decade changes in disease prevalence, mortality, or disability rates (from the years 2005 to 2015 [4-6], as well as the GBD Study 2013 that summarizes disease prevalence changes over a longer time horizon from 1990 to 2013 [7].

Small changes in climate can profoundly alter the dynamics and ecosystem services of tropical crater lakes.

Science.gov (United States)

Saulnier-Talbot, Émilie; Gregory-Eaves, Irene; Simpson, Kyle G; Efitre, Jackson; Nowlan, Tobias E; Taranu, Zofia E; Chapman, Lauren J

2014-01-01

African tropical lakes provide vital ecosystem services including food and water to some of the fastest growing human populations, yet they are among the most understudied ecosystems in the world. The consequences of climate change and other stressors on the tropical lakes of Africa have been informed by long-term analyses, but these studies have largely focused on the massive Great Rift Valley lakes. Our objective was to evaluate how recent climate change has altered the functioning and services of smaller tropical lakes, which are far more abundant on the landscape. Based on a paired analysis of 20 years of high-resolution water column data and a paleolimnological record from a small crater lake in western Uganda, we present evidence that even a modest warming of the air (∼0.9°C increase over 20 years) and changes in the timing and intensity of rainfall can have significant consequences on the dynamics of this common tropical lake type. For example, we observed a significant nonlinear increase (R(2) adj  = 0.23, e.d.f. = 7, pdeterioration of fish habitat and appears to have abated primary production; processes that may impair ecosystem services for a vulnerable human population. This study on a system representative of small tropical crater lakes highlights the far-reaching effects of global climatic change on tropical waters. Increased research efforts into tropical aquatic ecosystem health and the development of sound management practices are necessary in order to strengthen adaptive capabilities in tropical regions.

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...

Height-diameter allometry of tropical forest trees

Science.gov (United States)

T.R. Feldpausch; L. Banin; O.L. Phillips; T.R. Baker; S.L. Lewis; C.A. Quesada; K. Affum-Baffoe; E.J.M.M. Arets; N.J. Berry; M. Bird; E.S. Brondizio; P de Camargo; J. Chave; G. Djagbletey; T.F. Domingues; M. Drescher; P.M. Fearnside; M.B. Franca; N.M. Fyllas; G. Lopez-Gonzalez; A. Hladik; N. Higuchi; M.O. Hunter; Y. Iida; K.A. Salim; A.R. Kassim; M. Keller; J. Kemp; D.A. King; J.C. Lovett; B.S. Marimon; B.H. Marimon-Junior; E. Lenza; A.R. Marshall; D.J. Metcalfe; E.T.A. Mitchard; E.F. Moran; B.W. Nelson; R. Nilus; E.M. Nogueira; M. Palace; S. Patiño; K.S.-H. Peh; M.T. Raventos; J.M. Reitsma; G. Saiz; F. Schrodt; B. Sonke; H.E. Taedoumg; S. Tan; L. White; H. Woll; J. Lloyd

2011-01-01

Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical...

Using Enabling Technologies to Advance Data Intensive Analysis Tools in the JPL Tropical Cyclone Information System

Science.gov (United States)

Knosp, B.; Gangl, M. E.; Hristova-Veleva, S. M.; Kim, R. M.; Lambrigtsen, B.; Li, P.; Niamsuwan, N.; Shen, T. P. J.; Turk, F. J.; Vu, Q. A.

2014-12-01

The JPL Tropical Cyclone Information System (TCIS) brings together satellite, aircraft, and model forecast data from several NASA, NOAA, and other data centers to assist researchers in comparing and analyzing data related to tropical cyclones. The TCIS has been supporting specific science field campaigns, such as the Genesis and Rapid Intensification Processes (GRIP) campaign and the Hurricane and Severe Storm Sentinel (HS3) campaign, by creating near real-time (NRT) data visualization portals. These portals are intended to assist in mission planning, enhance the understanding of current physical processes, and improve model data by comparing it to satellite and aircraft observations. The TCIS NRT portals allow the user to view plots on a Google Earth interface. To compliment these visualizations, the team has been working on developing data analysis tools to let the user actively interrogate areas of Level 2 swath and two-dimensional plots they see on their screen. As expected, these observation and model data are quite voluminous and bottlenecks in the system architecture can occur when the databases try to run geospatial searches for data files that need to be read by the tools. To improve the responsiveness of the data analysis tools, the TCIS team has been conducting studies on how to best store Level 2 swath footprints and run sub-second geospatial searches to discover data. The first objective was to improve the sampling accuracy of the footprints being stored in the TCIS database by comparing the Java-based NASA PO.DAAC Level 2 Swath Generator with a TCIS Python swath generator. The second objective was to compare the performance of four database implementations - MySQL, MySQL+Solr, MongoDB, and PostgreSQL - to see which database management system would yield the best geospatial query and storage performance. The final objective was to integrate our chosen technologies with our Joint Probability Density Function (Joint PDF), Wave Number Analysis, and

Human Influence on Tropical Cyclone Intensity

Science.gov (United States)

Sobel, Adam H.; Camargo, Suzana J.; Hall, Timothy M.; Lee, Chia-Ying; Tippett, Michael K.; Wing, Allison A.

2016-01-01

Recent assessments agree that tropical cyclone intensity should increase as the climate warms. Less agreement exists on the detection of recent historical trends in tropical cyclone intensity.We interpret future and recent historical trends by using the theory of potential intensity, which predicts the maximum intensity achievable by a tropical cyclone in a given local environment. Although greenhouse gas-driven warming increases potential intensity, climate model simulations suggest that aerosol cooling has largely canceled that effect over the historical record. Large natural variability complicates analysis of trends, as do poleward shifts in the latitude of maximum intensity. In the absence of strong reductions in greenhouse gas emissions, future greenhouse gas forcing of potential intensity will increasingly dominate over aerosol forcing, leading to substantially larger increases in tropical cyclone intensities.

Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection

Science.gov (United States)

Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

2016-01-01

Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection. PMID:26838053

Global Warming Attenuates the Tropical Atlantic-Pacific Teleconnection.

Science.gov (United States)

Jia, Fan; Wu, Lixin; Gan, Bolan; Cai, Wenju

2016-02-03

Changes in global sea surface temperature (SST) since the end of last century display a pattern of widespread warming intercepted by cooling in the eastern equatorial Pacific and western coasts of the American continent. Studies have suggested that the cooling in the eastern equatorial Pacific may be partly induced by warming in the North Atlantic. However, it remains unknown how stable this inter-tropical teleconnection will be under global warming. Here we show that the inter-tropical teleconnection from the tropical Atlantic to Pacific weakens substantially as the CO2 concentration increases. This reduced impact is related to the El Niño-like warming of the tropical Pacific mean state, which leads to limited seasonal migration of the Pacific inter-tropical convergence zone (ITCZ) and weakened ocean heat transport. A fast decay of the tropical Atlantic SST anomalies in a warmer climate also contributes to the weakened teleconnection. Our study suggests that as greenhouse warming continues, the trend in the tropical Pacific as well as the development of ENSO will be less frequently interrupted by the Atlantic because of this attenuation. The weakened teleconnection is also supported by CMIP5 models, although only a few of these models can capture this inter-tropical teleconnection.

Physical and meteorological data from the Tropical Atmosphere Ocean (TAO) array in the tropical Pacific Ocean

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Tropical Atmosphere Ocean (TAO) Array of 55 moored buoys spans the tropical Pacific from longitudes 165°E to 95°W between latitudes of approximately 8°S and...

Multiple successional pathways in human-modified tropical landscapes

NARCIS (Netherlands)

Arroyo-Rodríguez, Víctor; Melo, Felipe P.L.; Martínez-Ramos, Miguel; Bongers, Frans; Chazdon, Robin L.; Meave, Jorge A.; Norden, Natalia; Santos, Bráulio A.; Leal, Inara R.; Tabarelli, Marcelo

2017-01-01

Old-growth tropical forests are being extensively deforested and fragmented worldwide. Yet forest recovery through succession has led to an expansion of secondary forests in human-modified tropical landscapes (HMTLs). Secondary forests thus emerge as a potential repository for tropical

Applying Climatically Associated Species Pools to modelling compositional change in tropical montane forests

NARCIS (Netherlands)

Golicher, J.D.; Cayuela, L.; Alkemade, J.R.M.; González-Espinosa, M.; Ramírez-Marcial, N.

2008-01-01

Aim Predictive species distribution modelling is a useful tool for extracting the maximum amount of information from biological collections and floristic inventories. However, in many tropical regions records are only available from a small number of sites. This can limit the application of

The transparency, reliability and utility of tropical rainforest land-use and land-cover change models.

Science.gov (United States)

Rosa, Isabel M D; Ahmed, Sadia E; Ewers, Robert M

2014-06-01

Land-use and land-cover (LULC) change is one of the largest drivers of biodiversity loss and carbon emissions globally. We use the tropical rainforests of the Amazon, the Congo basin and South-East Asia as a case study to investigate spatial predictive models of LULC change. Current predictions differ in their modelling approaches, are highly variable and often poorly validated. We carried out a quantitative review of 48 modelling methodologies, considering model spatio-temporal scales, inputs, calibration and validation methods. In addition, we requested model outputs from each of the models reviewed and carried out a quantitative assessment of model performance for tropical LULC predictions in the Brazilian Amazon. We highlight existing shortfalls in the discipline and uncover three key points that need addressing to improve the transparency, reliability and utility of tropical LULC change models: (1) a lack of openness with regard to describing and making available the model inputs and model code; (2) the difficulties of conducting appropriate model validations; and (3) the difficulty that users of tropical LULC models face in obtaining the model predictions to help inform their own analyses and policy decisions. We further draw comparisons between tropical LULC change models in the tropics and the modelling approaches and paradigms in other disciplines, and suggest that recent changes in the climate change and species distribution modelling communities may provide a pathway that tropical LULC change modellers may emulate to further improve the discipline. Climate change models have exerted considerable influence over public perceptions of climate change and now impact policy decisions at all political levels. We suggest that tropical LULC change models have an equally high potential to influence public opinion and impact the development of land-use policies based on plausible future scenarios, but, to do that reliably may require further improvements in the

Which statistics should tropical biologists learn?

Science.gov (United States)

Loaiza Velásquez, Natalia; González Lutz, María Isabel; Monge-Nájera, Julián

2011-09-01

Tropical biologists study the richest and most endangered biodiversity in the planet, and in these times of climate change and mega-extinctions, the need for efficient, good quality research is more pressing than in the past. However, the statistical component in research published by tropical authors sometimes suffers from poor quality in data collection; mediocre or bad experimental design and a rigid and outdated view of data analysis. To suggest improvements in their statistical education, we listed all the statistical tests and other quantitative analyses used in two leading tropical journals, the Revista de Biología Tropical and Biotropica, during a year. The 12 most frequent tests in the articles were: Analysis of Variance (ANOVA), Chi-Square Test, Student's T Test, Linear Regression, Pearson's Correlation Coefficient, Mann-Whitney U Test, Kruskal-Wallis Test, Shannon's Diversity Index, Tukey's Test, Cluster Analysis, Spearman's Rank Correlation Test and Principal Component Analysis. We conclude that statistical education for tropical biologists must abandon the old syllabus based on the mathematical side of statistics and concentrate on the correct selection of these and other procedures and tests, on their biological interpretation and on the use of reliable and friendly freeware. We think that their time will be better spent understanding and protecting tropical ecosystems than trying to learn the mathematical foundations of statistics: in most cases, a well designed one-semester course should be enough for their basic requirements.

Small changes in climate can profoundly alter the dynamics and ecosystem services of tropical crater lakes.

Directory of Open Access Journals (Sweden)

Émilie Saulnier-Talbot

Full Text Available African tropical lakes provide vital ecosystem services including food and water to some of the fastest growing human populations, yet they are among the most understudied ecosystems in the world. The consequences of climate change and other stressors on the tropical lakes of Africa have been informed by long-term analyses, but these studies have largely focused on the massive Great Rift Valley lakes. Our objective was to evaluate how recent climate change has altered the functioning and services of smaller tropical lakes, which are far more abundant on the landscape. Based on a paired analysis of 20 years of high-resolution water column data and a paleolimnological record from a small crater lake in western Uganda, we present evidence that even a modest warming of the air (∼0.9°C increase over 20 years and changes in the timing and intensity of rainfall can have significant consequences on the dynamics of this common tropical lake type. For example, we observed a significant nonlinear increase (R(2 adj  = 0.23, e.d.f. = 7, p<0.0001 in thermal stability over the past 20 years. This resulted in the expansion of anoxic waters and consequent deterioration of fish habitat and appears to have abated primary production; processes that may impair ecosystem services for a vulnerable human population. This study on a system representative of small tropical crater lakes highlights the far-reaching effects of global climatic change on tropical waters. Increased research efforts into tropical aquatic ecosystem health and the development of sound management practices are necessary in order to strengthen adaptive capabilities in tropical regions.

Diversity and carbon storage across the tropical forest biome

Science.gov (United States)

Sullivan, Martin J. P.; Talbot, Joey; Lewis, Simon L.; Phillips, Oliver L.; Qie, Lan; Begne, Serge K.; Chave, Jerôme; Cuni-Sanchez, Aida; Hubau, Wannes; Lopez-Gonzalez, Gabriela; Miles, Lera; Monteagudo-Mendoza, Abel; Sonké, Bonaventure; Sunderland, Terry; Ter Steege, Hans; White, Lee J. T.; Affum-Baffoe, Kofi; Aiba, Shin-Ichiro; de Almeida, Everton Cristo; de Oliveira, Edmar Almeida; Alvarez-Loayza, Patricia; Dávila, Esteban Álvarez; Andrade, Ana; Aragão, Luiz E. O. C.; Ashton, Peter; Aymard C., Gerardo A.; Baker, Timothy R.; Balinga, Michael; Banin, Lindsay F.; Baraloto, Christopher; Bastin, Jean-Francois; Berry, Nicholas; Bogaert, Jan; Bonal, Damien; Bongers, Frans; Brienen, Roel; Camargo, José Luís C.; Cerón, Carlos; Moscoso, Victor Chama; Chezeaux, Eric; Clark, Connie J.; Pacheco, Álvaro Cogollo; Comiskey, James A.; Valverde, Fernando Cornejo; Coronado, Eurídice N. Honorio; Dargie, Greta; Davies, Stuart J.; de Canniere, Charles; Djuikouo K., Marie Noel; Doucet, Jean-Louis; Erwin, Terry L.; Espejo, Javier Silva; Ewango, Corneille E. N.; Fauset, Sophie; Feldpausch, Ted R.; Herrera, Rafael; Gilpin, Martin; Gloor, Emanuel; Hall, Jefferson S.; Harris, David J.; Hart, Terese B.; Kartawinata, Kuswata; Kho, Lip Khoon; Kitayama, Kanehiro; Laurance, Susan G. W.; Laurance, William F.; Leal, Miguel E.; Lovejoy, Thomas; Lovett, Jon C.; Lukasu, Faustin Mpanya; Makana, Jean-Remy; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S.; Junior, Ben Hur Marimon; Marshall, Andrew R.; Morandi, Paulo S.; Mukendi, John Tshibamba; Mukinzi, Jaques; Nilus, Reuben; Vargas, Percy Núñez; Camacho, Nadir C. Pallqui; Pardo, Guido; Peña-Claros, Marielos; Pétronelli, Pascal; Pickavance, Georgia C.; Poulsen, Axel Dalberg; Poulsen, John R.; Primack, Richard B.; Priyadi, Hari; Quesada, Carlos A.; Reitsma, Jan; Réjou-Méchain, Maxime; Restrepo, Zorayda; Rutishauser, Ervan; Salim, Kamariah Abu; Salomão, Rafael P.; Samsoedin, Ismayadi; Sheil, Douglas; Sierra, Rodrigo; Silveira, Marcos; Slik, J. W. Ferry; Steel, Lisa; Taedoumg, Hermann; Tan, Sylvester; Terborgh, John W.; Thomas, Sean C.; Toledo, Marisol; Umunay, Peter M.; Gamarra, Luis Valenzuela; Vieira, Ima Célia Guimarães; Vos, Vincent A.; Wang, Ophelia; Willcock, Simon; Zemagho, Lise

2017-01-01

Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1 ha plots, indicating that diversity effects in tropical forests may be scale dependent. The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies will inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both require explicit consideration when optimising policies to manage tropical carbon and biodiversity.

Diversity and carbon storage across the tropical forest biome.

Science.gov (United States)

Sullivan, Martin J P; Talbot, Joey; Lewis, Simon L; Phillips, Oliver L; Qie, Lan; Begne, Serge K; Chave, Jerôme; Cuni-Sanchez, Aida; Hubau, Wannes; Lopez-Gonzalez, Gabriela; Miles, Lera; Monteagudo-Mendoza, Abel; Sonké, Bonaventure; Sunderland, Terry; Ter Steege, Hans; White, Lee J T; Affum-Baffoe, Kofi; Aiba, Shin-Ichiro; de Almeida, Everton Cristo; de Oliveira, Edmar Almeida; Alvarez-Loayza, Patricia; Dávila, Esteban Álvarez; Andrade, Ana; Aragão, Luiz E O C; Ashton, Peter; Aymard C, Gerardo A; Baker, Timothy R; Balinga, Michael; Banin, Lindsay F; Baraloto, Christopher; Bastin, Jean-Francois; Berry, Nicholas; Bogaert, Jan; Bonal, Damien; Bongers, Frans; Brienen, Roel; Camargo, José Luís C; Cerón, Carlos; Moscoso, Victor Chama; Chezeaux, Eric; Clark, Connie J; Pacheco, Álvaro Cogollo; Comiskey, James A; Valverde, Fernando Cornejo; Coronado, Eurídice N Honorio; Dargie, Greta; Davies, Stuart J; De Canniere, Charles; Djuikouo K, Marie Noel; Doucet, Jean-Louis; Erwin, Terry L; Espejo, Javier Silva; Ewango, Corneille E N; Fauset, Sophie; Feldpausch, Ted R; Herrera, Rafael; Gilpin, Martin; Gloor, Emanuel; Hall, Jefferson S; Harris, David J; Hart, Terese B; Kartawinata, Kuswata; Kho, Lip Khoon; Kitayama, Kanehiro; Laurance, Susan G W; Laurance, William F; Leal, Miguel E; Lovejoy, Thomas; Lovett, Jon C; Lukasu, Faustin Mpanya; Makana, Jean-Remy; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S; Junior, Ben Hur Marimon; Marshall, Andrew R; Morandi, Paulo S; Mukendi, John Tshibamba; Mukinzi, Jaques; Nilus, Reuben; Vargas, Percy Núñez; Camacho, Nadir C Pallqui; Pardo, Guido; Peña-Claros, Marielos; Pétronelli, Pascal; Pickavance, Georgia C; Poulsen, Axel Dalberg; Poulsen, John R; Primack, Richard B; Priyadi, Hari; Quesada, Carlos A; Reitsma, Jan; Réjou-Méchain, Maxime; Restrepo, Zorayda; Rutishauser, Ervan; Salim, Kamariah Abu; Salomão, Rafael P; Samsoedin, Ismayadi; Sheil, Douglas; Sierra, Rodrigo; Silveira, Marcos; Slik, J W Ferry; Steel, Lisa; Taedoumg, Hermann; Tan, Sylvester; Terborgh, John W; Thomas, Sean C; Toledo, Marisol; Umunay, Peter M; Gamarra, Luis Valenzuela; Vieira, Ima Célia Guimarães; Vos, Vincent A; Wang, Ophelia; Willcock, Simon; Zemagho, Lise

2017-01-17

Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1 ha plots, indicating that diversity effects in tropical forests may be scale dependent. The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies will inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both require explicit consideration when optimising policies to manage tropical carbon and biodiversity.

Modeling fire behavior on tropical islands with high-resolution weather data

Science.gov (United States)

John W. Benoit; Francis M. Fujioka; David R. Weise

2009-01-01

In this study, we consider fire behavior simulation in tropical island scenarios such as Hawaii and Puerto Rico. The development of a system to provide real-time fire behavior prediction in Hawaii is discussed. This involves obtaining fuels and topography information at a fine scale, as well as supplying daily high-resolution weather forecast data for the area of...

[Contribution of tropical upland forests to carbon storage in Colombia].

Science.gov (United States)

Yepes, Adriana; Herrera, Johana; Phillips, Juan; Galindo, Gustavo; Granados, Edwin; Duque, Alvaro; Barbosa, Adriana; Olarte, Claudia; Cardona, María

2015-03-01

The tropical montane forests in the Colombian Andean region are located above 1500 m, and have been heavily deforested. Despite the general presumption that productivity and hence carbon stocks in these ecosystems are low, studies in this regard are scarce. This study aimed to (i) to estimate Above Ground Biomass (AGB) in forests located in the South of the Colombian Andean region, (ii) to identify the carbon storage potential of tropical montane forests dominated by the black oak Colombobalanus excelsa and to identify the relationship between AGB and altitude, and (iii) to analyze the role of tropical mountain forests in conservation mechanisms such as Payment for Environmental Services (PES) and Reducing Emissions from Deforestation and Degradation (REDD+). Twenty six 0.25 ha plots were randomly distributed in the forests and all trees with D > or =10 cm were measured. The results provided important elements for understanding the role of tropical montane forests as carbon sinks. The information produced can be used in subnational initiatives, which seek to mitigate or reduce the effects of deforestation through management or conservation of these ecosystems, like REDD+ or PES. The AGB and carbon stocks results obtained were similar to those reported for lowland tropical forests. These could be explained by the dominance and abundance of C. excelsa, which accounted for over 81% of AGB/carbon. The error associated with the estimates of AGB/carbon was 10.58%. We found a negative and significant relationship between AGB and altitude, but the higher AGB values were in middle altitudes (approximatly = 700-1800 m), where the environmental conditions could be favorable to their growth. The carbon storage potential of these forests was higher. However, if the historical rate of the deforestation in the study area continues, the gross emissions of CO2e to the atmosphere could turn these forests in to an important emissions source. Nowadays, it is clear that tropical

International Journal of Malaria and Tropical Diseases (IJMTD)

African Journals Online (AJOL)

The International Journal of Malaria and Tropical Diseases (IJMTD) (formally known was the Journal of Malaria in Africa and the Tropics (JMAT) is a publication of the malariologists and researchers in tropical diseases. Its aim is to educate, improved the practice of malaria treatment, stimulate research, encourage academic ...

Homological mirror symmetry and tropical geometry

CERN Document Server

Catanese, Fabrizio; Kontsevich, Maxim; Pantev, Tony; Soibelman, Yan; Zharkov, Ilia

2014-01-01

The relationship between Tropical Geometry and Mirror Symmetry goes back to the work of Kontsevich and Y. Soibelman (2000), who applied methods of non-archimedean geometry (in particular, tropical curves) to Homological Mirror Symmetry. In combination with the subsequent work of Mikhalkin on the “tropical” approach to Gromov-Witten theory, and the work of Gross and Siebert, Tropical Geometry has now become a powerful tool. Homological Mirror Symmetry is the area of mathematics concentrated around several categorical equivalences connecting symplectic and holomorphic (or algebraic) geometry. The central ideas first appeared in the work of Maxim Kontsevich (1993). Roughly speaking, the subject can be approached in two ways: either one uses Lagrangian torus fibrations of Calabi-Yau manifolds (the so-called Strominger-Yau-Zaslow picture, further developed by Kontsevich and Soibelman) or one uses Lefschetz fibrations of symplectic manifolds (suggested by Kontsevich and further developed by Seidel). Tropical Ge...

Lightning and 85-GHz MCSs in the Global Tropics

Science.gov (United States)

Toracinta, E. Richard; Zipser, E. J.

1999-01-01

Numerous observations of tropical convection show that tropical continental mesoscale convective systems (MCSs) are much more prolific lightning producers than their oceanic counterparts. Satellite-based climatologies using 85-GHz passive microwave ice-scattering signatures from the Special Sensor Microwave/Imager (SSM/I) indicate that MCSs of various size and intensity are found throughout the global tropics. In contrast, global lightning distributions show a strong land bias with an order of magnitude difference between land and ocean lightning. This is somewhat puzzling, since 85-GHz ice-scattering and the charge separation processes that lead to lightning are both thought to depend upon the existence of large graupel particles. The fact that low 85-GHz brightness temperatures are observed in tropical oceanic MCSs containing virtually no lightning leads to the postulate that tropical oceanic and tropical continental MCSs have fundamentally different hydrometeor profiles through the mixed phase region of the cloud (0 C Lightning Imaging Sensor (LIS), and the first space-borne radar, facilitates high-resolution case studies of MCS structure throughout the global tropics. An important precursor, however, is to better understand the distribution of MCSs and lightning in the tropics. With that objective in mind, this research undertakes a systematic comparison of 85-GHz-defined MCSs and lightning over the global tropics for a full year, as an initial step toward quantifying differences between land and ocean convective systems.

Species undersampling in tropical bat surveys: effects on emerging biodiversity patterns.

Science.gov (United States)

Meyer, Christoph F J; Aguiar, Ludmilla M S; Aguirre, Luis F; Baumgarten, Julio; Clarke, Frank M; Cosson, Jean-François; Estrada Villegas, Sergio; Fahr, Jakob; Faria, Deborah; Furey, Neil; Henry, Mickaël; Jenkins, Richard K B; Kunz, Thomas H; Cristina MacSwiney González, M; Moya, Isabel; Pons, Jean-Marc; Racey, Paul A; Rex, Katja; Sampaio, Erica M; Stoner, Kathryn E; Voigt, Christian C; von Staden, Dietrich; Weise, Christa D; Kalko, Elisabeth K V

2015-01-01

Undersampling is commonplace in biodiversity surveys of species-rich tropical assemblages in which rare taxa abound, with possible repercussions for our ability to implement surveys and monitoring programmes in a cost-effective way. We investigated the consequences of information loss due to species undersampling (missing subsets of species from the full species pool) in tropical bat surveys for the emerging patterns of species richness (SR) and compositional variation across sites. For 27 bat assemblage data sets from across the tropics, we used correlations between original data sets and subsets with different numbers of species deleted either at random, or according to their rarity in the assemblage, to assess to what extent patterns in SR and composition in data subsets are congruent with those in the initial data set. We then examined to what degree high sample representativeness (r ≥ 0·8) was influenced by biogeographic region, sampling method, sampling effort or structural assemblage characteristics. For SR, correlations between random subsets and original data sets were strong (r ≥ 0·8) with moderate (ca. 20%) species loss. Bias associated with information loss was greater for species composition; on average ca. 90% of species in random subsets had to be retained to adequately capture among-site variation. For nonrandom subsets, removing only the rarest species (on average c. 10% of the full data set) yielded strong correlations (r > 0·95) for both SR and composition. Eliminating greater proportions of rare species resulted in weaker correlations and large variation in the magnitude of observed correlations among data sets. Species subsets that comprised ca. 85% of the original set can be considered reliable surrogates, capable of adequately revealing patterns of SR and temporal or spatial turnover in many tropical bat assemblages. Our analyses thus demonstrate the potential as well as limitations for reducing survey effort and streamlining

Tropical Deforestation.

Science.gov (United States)

Raven, Peter H.

1988-01-01

Outlines the deforestation problem and some efforts for solving the problem. Considers the impact of population growth, poverty, and ignorance. Includes a discussion of the current rapid decline in tropical forests, the consequences of destruction, and an outlook for the future. (YP)

Journal of Tropical Microbiology and Biotechnology

African Journals Online (AJOL)

The Journal of Tropical Microbiology and Biotechnology (JTMB) formerly Journal of Tropical Microbiology gives preeminence to the central role of modern biotechnology and microorganisms as tools and targets in current research, which is largely multidisciplinary. JTMB covers a broad range of topics, such as disease ...

The Role of the Tropics in Abrupt Climate Changes

Energy Technology Data Exchange (ETDEWEB)

Fedorov, Alexey [Yale University

2013-12-07

Topics addressed include: abrupt climate changes and ocean circulation in the tropics; what controls the ocean thermal structure in the tropics; a permanent El Niño in paleoclimates; the energetics of the tropical ocean.

Urgent need for warming experiments in tropical forests

Science.gov (United States)

Calaveri, Molly A.; Reed, Sasha C.; Smith, W. Kolby; Wood, Tana E.

2015-01-01

Although tropical forests account for only a fraction of the planet's terrestrial surface, they exchange more carbon dioxide with the atmosphere than any other biome on Earth, and thus play a disproportionate role in the global climate. In the next 20 years, the tropics will experience unprecedented warming, yet there is exceedingly high uncertainty about their potential responses to this imminent climatic change. Here, we prioritize research approaches given both funding and logistical constraints in order to resolve major uncertainties about how tropical forests function and also to improve predictive capacity of earth system models. We investigate overall model uncertainty of tropical latitudes and explore the scientific benefits and inevitable trade-offs inherent in large-scale manipulative field experiments. With a Coupled Model Intercomparison Project Phase 5 analysis, we found that model variability in projected net ecosystem production was nearly 3 times greater in the tropics than for any other latitude. Through a review of the most current literature, we concluded that manipulative warming experiments are vital to accurately predict future tropical forest carbon balance, and we further recommend the establishment of a network of comparable studies spanning gradients of precipitation, edaphic qualities, plant types, and/or land use change. We provide arguments for long-term, single-factor warming experiments that incorporate warming of the most biogeochemically active ecosystem components (i.e. leaves, roots, soil microbes). Hypothesis testing of underlying mechanisms should be a priority, along with improving model parameterization and constraints. No single tropical forest is representative of all tropical forests; therefore logistical feasibility should be the most important consideration for locating large-scale manipulative experiments. Above all, we advocate for multi-faceted research programs, and we offer arguments for what we consider the most

Standardized Assessment of Biodiversity Trends in Tropical Forest Protected Areas: The End Is Not in Sight.

Directory of Open Access Journals (Sweden)

Lydia Beaudrot

2016-01-01

Full Text Available Extinction rates in the Anthropocene are three orders of magnitude higher than background and disproportionately occur in the tropics, home of half the world's species. Despite global efforts to combat tropical species extinctions, lack of high-quality, objective information on tropical biodiversity has hampered quantitative evaluation of conservation strategies. In particular, the scarcity of population-level monitoring in tropical forests has stymied assessment of biodiversity outcomes, such as the status and trends of animal populations in protected areas. Here, we evaluate occupancy trends for 511 populations of terrestrial mammals and birds, representing 244 species from 15 tropical forest protected areas on three continents. For the first time to our knowledge, we use annual surveys from tropical forests worldwide that employ a standardized camera trapping protocol, and we compute data analytics that correct for imperfect detection. We found that occupancy declined in 22%, increased in 17%, and exhibited no change in 22% of populations during the last 3-8 years, while 39% of populations were detected too infrequently to assess occupancy changes. Despite extensive variability in occupancy trends, these 15 tropical protected areas have not exhibited systematic declines in biodiversity (i.e., occupancy, richness, or evenness at the community level. Our results differ from reports of widespread biodiversity declines based on aggregated secondary data and expert opinion and suggest less extreme deterioration in tropical forest protected areas. We simultaneously fill an important conservation data gap and demonstrate the value of large-scale monitoring infrastructure and powerful analytics, which can be scaled to incorporate additional sites, ecosystems, and monitoring methods. In an era of catastrophic biodiversity loss, robust indicators produced from standardized monitoring infrastructure are critical to accurately assess population outcomes

Standardized Assessment of Biodiversity Trends in Tropical Forest Protected Areas: The End Is Not in Sight.

Science.gov (United States)

Beaudrot, Lydia; Ahumada, Jorge A; O'Brien, Timothy; Alvarez-Loayza, Patricia; Boekee, Kelly; Campos-Arceiz, Ahimsa; Eichberg, David; Espinosa, Santiago; Fegraus, Eric; Fletcher, Christine; Gajapersad, Krisna; Hallam, Chris; Hurtado, Johanna; Jansen, Patrick A; Kumar, Amit; Larney, Eileen; Lima, Marcela Guimarães Moreira; Mahony, Colin; Martin, Emanuel H; McWilliam, Alex; Mugerwa, Badru; Ndoundou-Hockemba, Mireille; Razafimahaimodison, Jean Claude; Romero-Saltos, Hugo; Rovero, Francesco; Salvador, Julia; Santos, Fernanda; Sheil, Douglas; Spironello, Wilson R; Willig, Michael R; Winarni, Nurul L; Zvoleff, Alex; Andelman, Sandy J

2016-01-01

Extinction rates in the Anthropocene are three orders of magnitude higher than background and disproportionately occur in the tropics, home of half the world's species. Despite global efforts to combat tropical species extinctions, lack of high-quality, objective information on tropical biodiversity has hampered quantitative evaluation of conservation strategies. In particular, the scarcity of population-level monitoring in tropical forests has stymied assessment of biodiversity outcomes, such as the status and trends of animal populations in protected areas. Here, we evaluate occupancy trends for 511 populations of terrestrial mammals and birds, representing 244 species from 15 tropical forest protected areas on three continents. For the first time to our knowledge, we use annual surveys from tropical forests worldwide that employ a standardized camera trapping protocol, and we compute data analytics that correct for imperfect detection. We found that occupancy declined in 22%, increased in 17%, and exhibited no change in 22% of populations during the last 3-8 years, while 39% of populations were detected too infrequently to assess occupancy changes. Despite extensive variability in occupancy trends, these 15 tropical protected areas have not exhibited systematic declines in biodiversity (i.e., occupancy, richness, or evenness) at the community level. Our results differ from reports of widespread biodiversity declines based on aggregated secondary data and expert opinion and suggest less extreme deterioration in tropical forest protected areas. We simultaneously fill an important conservation data gap and demonstrate the value of large-scale monitoring infrastructure and powerful analytics, which can be scaled to incorporate additional sites, ecosystems, and monitoring methods. In an era of catastrophic biodiversity loss, robust indicators produced from standardized monitoring infrastructure are critical to accurately assess population outcomes and identify

Standardized Assessment of Biodiversity Trends in Tropical Forest Protected Areas: The End Is Not in Sight

Science.gov (United States)

O'Brien, Timothy; Alvarez-Loayza, Patricia; Boekee, Kelly; Campos-Arceiz, Ahimsa; Eichberg, David; Espinosa, Santiago; Fegraus, Eric; Fletcher, Christine; Gajapersad, Krisna; Hallam, Chris; Hurtado, Johanna; Jansen, Patrick A.; Kumar, Amit; Larney, Eileen; Lima, Marcela Guimarães Moreira; Mahony, Colin; Martin, Emanuel H.; McWilliam, Alex; Mugerwa, Badru; Ndoundou-Hockemba, Mireille; Razafimahaimodison, Jean Claude; Romero-Saltos, Hugo; Rovero, Francesco; Salvador, Julia; Santos, Fernanda; Sheil, Douglas; Spironello, Wilson R.; Willig, Michael R.; Winarni, Nurul L.; Zvoleff, Alex; Andelman, Sandy J.

2016-01-01

Extinction rates in the Anthropocene are three orders of magnitude higher than background and disproportionately occur in the tropics, home of half the world’s species. Despite global efforts to combat tropical species extinctions, lack of high-quality, objective information on tropical biodiversity has hampered quantitative evaluation of conservation strategies. In particular, the scarcity of population-level monitoring in tropical forests has stymied assessment of biodiversity outcomes, such as the status and trends of animal populations in protected areas. Here, we evaluate occupancy trends for 511 populations of terrestrial mammals and birds, representing 244 species from 15 tropical forest protected areas on three continents. For the first time to our knowledge, we use annual surveys from tropical forests worldwide that employ a standardized camera trapping protocol, and we compute data analytics that correct for imperfect detection. We found that occupancy declined in 22%, increased in 17%, and exhibited no change in 22% of populations during the last 3–8 years, while 39% of populations were detected too infrequently to assess occupancy changes. Despite extensive variability in occupancy trends, these 15 tropical protected areas have not exhibited systematic declines in biodiversity (i.e., occupancy, richness, or evenness) at the community level. Our results differ from reports of widespread biodiversity declines based on aggregated secondary data and expert opinion and suggest less extreme deterioration in tropical forest protected areas. We simultaneously fill an important conservation data gap and demonstrate the value of large-scale monitoring infrastructure and powerful analytics, which can be scaled to incorporate additional sites, ecosystems, and monitoring methods. In an era of catastrophic biodiversity loss, robust indicators produced from standardized monitoring infrastructure are critical to accurately assess population outcomes and identify

Characterizing Tropical Forest Cover Loss Using Dense Sentinel-1 Data and Active Fire Alerts

NARCIS (Netherlands)

Reiche, Johannes; Verhoeven, Rob; Verbesselt, Jan; Hamunyela, Eliakim; Wielaard, Niels; Herold, Martin

2018-01-01

Fire use for land management is widespread in natural tropical and plantation forests, causing major environmental and economic damage. Recent studies combining active fire alerts with annual forest-cover loss information identified fire-related forest-cover loss areas well, but do not provide

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.

Chemical form of tumor-tropic 99mTc-DL-homocysteine

International Nuclear Information System (INIS)

Takeda, A.; Okada, S.

1989-01-01

Analyses of the chemical forms of 99m Tc-complexes provide important information for the development of a new tumor-tropic 99m Tc-labeled radiopharmaceutical. We attempted to determine the chemical form of 99m Tc-DL-homocysteine ( 99m Tc-Hcy) which was previously reported to be tumor-tropic. By analyzing the functional residues of Hcy in the 99m Tc-Hcy molecule, it was estimated that the sulfhydryl and amino residues participated in the chelate formation. Gel filtration analysis of 99m Tc-Hcy indicated that its molecular size was bigger than that of 99m Tc-penicillamine monomer. The analysis also indicated that 99m Tc-Hcy complex seemed to be a relatively small oligomer. Although an uncertainty remains on the valency of Tc in 99m Tc-Hcy molecule and the accurate molecular size of this complex, its putative chemical form is described. (author)

Travel to tropical areas: Zika virus disease

CERN Multimedia

CERN Medical Service

2016-01-01

Transmitted by the bite of a certain species of mosquitoes (Aedes), the Zika virus is spreading quickly in tropical areas of Central America, the Caribbean and South America.   Although no specific treatment nor vaccine is currently available, the most effective preventive measures are those focused on avoiding mosquito bites. There are no travel restrictions in place at present. However it is recommended that pregnant women defer travel plans to countries affected by the Zika virus. For further information on symptoms and prevention measures, please click on the Zika virus link or contact the Medical Service.

The role of tropical cyclones in precipitation over the tropical and subtropical North America

Science.gov (United States)

Dominguez, Christian; Magaña, Victor

2018-03-01

Tropical cyclones (TCs) are essential elements of the hydrological cycle in tropical and subtropical regions. In the present study, the contribution of TCs to seasonal precipitation around the tropical and subtropical North America is examined. When TC activity over the tropical eastern Pacific (TEP) or the Intra Americas Seas (IAS) is below (above-normal), regional precipitation may be below (above-normal). However, it is not only the number of TCs what may change seasonal precipitation, but the trajectory of the systems. TCs induce intense precipitation over continental regions if they are close enough to shorelines, for instance, if the TC center is located, on average, less than 500 km-distant from the coast. However, if TCs are more remote than this threshold distance, the chances of rain over continental regions decrease, particularly in arid and semi-arid regions. In addition, a distant TC may induce subsidence or produce moisture divergence that inhibits, at least for a few days, convective activity farther away than the threshold distance. An analysis of interannual variability in the TCs that produce precipitation over the tropical and subtropical North America shows that some regions in northern Mexico, which mostly depend on this effect to undergo wet years, may experience seasonal negative anomalies in precipitation if TCs trajectories are remote. Therefore, TCs (activity and trajectories) are important modulators of climate variability on various time scales, either by producing intense rainfall or by inhibiting convection at distant regions from their trajectory. The impact of such variations on water availability in northern Mexico may be relevant, since water availability in dams recovers under the effects of TC rainfall. Seasonal precipitation forecasts or climate change scenarios for these regions should take into account the effect of TCs, if regional adaptation strategies are implemented.

Strategies for Improving Enterprise Standardization Management of Tropical Crop Machinery

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

@@ There are two categories of tropical crop machinery. One comprises operation machinery that is used for planting, managing and harvesting tropical crops, while the other comprises process machinery for processing tropical crops. Tropical crop machinery is distinguished from other agricultural machinery by the special crops that such machinery cultivates and processes.

Air-sea interaction in the tropical Pacific Ocean

Science.gov (United States)

Allison, L. J.; Steranka, J.; Holub, R. J.; Hansen, J.; Godshall, F. A.; Prabhakara, C.

1972-01-01

Charts of 3-month sea surface temperature (SST) anomalies in the eastern tropical Pacific Ocean were produced for the period 1949 to 1970. The anomalies along the United States and South American west coasts and in the eastern tropical Pacific appeared to be oscillating in phase during this period. Similarly, the satellite-derived cloudiness for each of four quadrants of the Pacific Ocean (130 deg E to 100 deg W, 30 deg N to 25 deg S) appeared to be oscillating in phase. In addition, a global tropical cloudiness oscillation from 30 deg N to 30 deg S was noted from 1965 to 1970, by using monthly satellite television nephanalyses. The SST anomalies were found to have a good degree of correlation both positive and negative with the following monthly geophysical parameters: (1) satellite-derived cloudiness, (2) strength of the North and South Pacific semipermanent anticyclones, (3) tropical Pacific island rainfall, and (4) Darwin surface pressure. Several strong direct local and crossequatorial relationships were noted. In particular, the high degree of correlation between the tropical island rainfall and the SST anomalies (r = +0.93) permitted the derivation of SST's for the tropical Pacific back to 1905. The close occurrence of cold tropical SST and North Pacific 700-mb positive height anomalies with central United States drought conditions was noted.

Phylogenetic classification of the world’s tropical forests

OpenAIRE

Slik, J. W. Ferry; Franklin, Janet; Arroyo-Rodríguez, Víctor; Field, Richard; Aguilar, Salomon; Aguirre, Nikolay; Ahumada, Jorge; Aiba, Shin-Ichiro; Alves, Luciana F.; K, Anitha; Avella, Andres; Mora, Francisco; Aymard C., Gerardo A.; Báez, Selene; Balvanera, Patricia

2018-01-01

Identifying and explaining regional differences in tropical forest dynamics, structure, diversity, and composition are critical for anticipating region-specific responses to global environmental change. Floristic classifications are of fundamental importance for these efforts. Here we provide a global tropical forest classification that is explicitly based on community evolutionary similarity, resulting in identification of five major tropical forest regions and their relationships: (i) Indo-...

Year 2001 Tropical Cyclones of the World

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Year 2001 Tropical Cyclones of the World poster. During calendar year 2001, fifty tropical cyclones with sustained surface winds of at least 64 knots were observed...

Year 2000 Tropical Cyclones of the World

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Year 2000 Tropical Cyclones of the World poster. During calendar year 2000, forty-five tropical cyclones with sustained surface winds of at least 64 knots were...

Contribution of landfalling tropical system rainfall to the hydroclimate of the eastern U.S. Corn Belt 1981–2012

Directory of Open Access Journals (Sweden)

Olivia Kellner

2016-09-01

Landfalling tropical system rainfall accounts for approximately 20% of the observed monthly rainfall during the tropical storm season (June–November across the eastern U.S. Corn Belt (1981–2012. Correlation between the annual number of landfalling tropical systems and annual yield by state results in no relationship, but correlation of August monthly observed rainfall by climate division to crop reporting district annual yields has a weak to moderate, statistically significant correlation in Ohio districts 30–60 and Indiana CRD 90. ANOVA analysis suggests that landfalling tropical rainfall may actually reduce yields in some state's climate divisions/crop reporting districts while increasing yield in others. Results suggest that there is a balance between landfalling tropical storms providing sufficient rainfall or too much rainfall to be of benefit to crops. Findings aim to provide information to producers, crop advisers, risk managers and commodity groups so that seasonal hurricane forecasts can potentially be utilized in planning for above or below normal precipitation during phenologically important portions of the growing season.

Forests to fields. Restoring tropical lands to agriculture.

Science.gov (United States)

Wood, D

1993-04-01

In discussing land use in tropical forest regions, there is an emphasis on the following topics: the need for the expansion of cropping areas, the precedent for use of the tropical forest for cropping based on past use patterns, the pressure from conservationists against cropping, debunking the mythology that forests are "natural" and refuting the claims that forest clearance is not reversible, the archeological evidence of past forest use for agricultural purposes, abandonment of tropical land to forest, and rotation of forest and field. The assumption is that the way to stop food importation is to increase crop production in the tropics. Crop production can be increased through 1) land intensification or clearing new land, 2) output per unit of land increases, or 3) reallocation to agriculture land previously cleared and overgrown with tropical forest. "Temporary" reuse of land, which reverted back to tropical forest, is recommended. This reuse would ease population pressure, and benefit bioconservation, while populations stabilize and further progress is made in international plant breeding. The land would eventually be returned to a forest state. Conservation of tropical forest areas should be accomplished, after an assessment has been made of its former uses. Primary forests need to identified and conversion to farming ceased. Research needs to be directed to understanding the process of past forest regeneration, and to devising cropping systems with longterm viability. The green revolution is unsuitable for traditional cropping systems, is contrary to demands of international funding agencies for sustainability, and is not affordable by most poor farmers. Only .48 million sq. km of closed forest loss was in tropical rainforests; 6.53 million sq. km was lost from temperate forests cleared for intensive small-scale peasant farming. The use of tropical forest land for farming has some benefits; crops in the wetter tropics are perennial, which would "reduce

Tropical Cyclone Signatures in Atmospheric Convective Available Potential Energy

Science.gov (United States)

Studholme, Joshua; Gulev, Sergey

2016-04-01

Tropical cyclones play an important role in the climate system providing transports of energy and water vapor, forcing the ocean, and also affecting mid-latitude circulation phenomena. Tropical cyclone tracks experience strong interannual variability and in addition, longer term trend-like changes in all ocean basins. Analysis of recent historical data reveal a poleward shift in the locations of tropical cyclone tracks in both the Northern and Southern Hemispheres (Kossin et al. 2014, Nature, 509, 349-352). The physical consequences of these alterations are largely unconstrained. For example, the increasing encroachment of tropical cyclone activity into the extra-tropical environment presents a novel and still poorly understood paradigm for tropical-extratropical interactions. In this respect, the role that the atmospheric convective available potential energy (CAPE) plays in the dynamics of tropical cyclones is highly interesting. The two characteristic global-scale spatial patterns in CAPE are identified using EOF analysis. The first pattern shows an abundance of CAPE in the centre of the Pacific and corresponds to the El Nino Southern Oscillation. The second one is capturing positive CAPE anomalies in the oceanic tropics and negative anomalies over equatorial Africa. Associated with these buoyancy patterns, alterations in tropical cyclone activity occur in all basins forming both zonal and meridional patterns. Atmospheric buoyancy is the trigger for deep convection, and subsequently cyclone genesis. This is the mechanism of impact upon location at the start of cyclone tracks. It is found to have less impact upon where cyclones subsequently move, whether or not they undergo extratropical transition and when and where they experience lysis. It is shown that CAPE plays a critical role in the general circulation in the tropics which in turn is the larger steering context for embedded systems within the Walker and Hadley cells. So this lack of `latter life' impact

Mineral components and anti-oxidant activities of tropical seaweeds

Science.gov (United States)

Takeshi, Suzuki; Yumiko, Yoshie-Stark; Joko, Santoso

2005-07-01

Seaweeds are known to hold substances of high nutritional value; they are the richest resources of minerals important to the biochemical reactions in the human body. Seaweeds also hold non-nutrient compounds like dietary fiber and polyphenols. However, there is not enough information on the mineral compounds of tropical seaweeds. Also we are interested in the antioxidant activities of seaweeds, especially those in the tropical area. In this study, Indonesian green, brown and red algae were used as experimental materials with their mineral components analyzed by using an atomic absorption spectrophotometer. The catechins and flavonoids of these seaweeds were extracted with methanol and analyzed by high performance liquid chromatography (HPLC); the antioxidant activities of these seaweeds were evaluated in a fish oil emulsion system. The mineral components of tropical seaweeds are dominated by calcium, potassium and sodium, as well as small amounts of copper, iron and zinc. A green alga usually contains epigallocatechin, gallocatechin, epigallocatechin gallate and catechin. However, catechin and its isomers are not found in some green and red algae. In the presence of a ferrous ion catalyst, all the methanol extracts from the seaweeds show significantly lower peroxide values of the emulsion than the control, and that of a green alga shows the strongest antioxidant activity. The highest chelation on ferrous ions is also found in the extract of this alga, which is significantly different from the other methanol extracts in both 3 and 24 h incubations.

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.

Carbon stock corridors to mitigate climate change and promote biodiversity in the tropics

Science.gov (United States)

Jantz, Patrick; Goetz, Scott; Laporte, Nadine

2014-02-01

A key issue in global conservation is how biodiversity co-benefits can be incorporated into land use and climate change mitigation activities, particularly those being negotiated under the United Nations to reduce emissions from tropical deforestation and forest degradation. Protected areas have been the dominant strategy for tropical forest conservation and they have increased substantially in recent decades. Avoiding deforestation by preserving carbon stored in vegetation between protected areas provides an opportunity to mitigate the effects of land use and climate change on biodiversity by maintaining habitat connectivity across landscapes. Here we use a high-resolution data set of vegetation carbon stock to map corridors traversing areas of highest biomass between protected areas in the tropics. The derived corridors contain 15% of the total unprotected aboveground carbon in the tropical region. A large number of corridors have carbon densities that approach or exceed those of the protected areas they connect, suggesting these are suitable areas for achieving both habitat connectivity and climate change mitigation benefits. To further illustrate how economic and biological information can be used for corridor prioritization on a regional scale, we conducted a multicriteria analysis of corridors in the Legal Amazon, identifying corridors with high carbon, high species richness and endemism, and low economic opportunity costs. We also assessed the vulnerability of corridors to future deforestation threat.

Mediterranean climate and some tropical teleconnections

International Nuclear Information System (INIS)

Alpert, P.; Price, C.; Krichak, S.; Saaroni, H.; Osetinsky, I.; Barkan, J.; Kishcha, P.; Ziv, B.

2006-01-01

Some strong natural fluctuations of climate in the Eastern Mediterranean (EM) region are shown to be connected to the major tropical systems, e.g., El Ni no Southern Oscillation, South Asian Monsoon and hurricanes. Modelling of the severe floods suggests a relation to tropical hurricanes. For a specific event, high-resolution modelling of the severe flood on December 3-5, 2001 in Israel suggests a relation to hurricane Olga. In order to understand the factors governing the Eastern Mediterranean climate variability in the summer season, the relationship between extreme summer temperatures and the South Asian Monsoon was examined. Other tropical factors, like the Red Sea Trough system and the Saharan dust, also contribute to the Mediterranean climate variability

Rapid wave and storm surge warning system for tropical cyclones in Mexico

Science.gov (United States)

Appendini, C. M.; Rosengaus, M.; Meza, R.; Camacho, V.

2015-12-01

The National Hurricane Center (NHC) in Miami, is responsible for the forecast of tropical cyclones in the North Atlantic and Eastern North Pacific basins. As such, Mexico, Central America and Caribbean countries depend on the information issued by the NHC related to the characteristics of a particular tropical cyclone and associated watch and warning areas. Despite waves and storm surge are important hazards for marine operations and coastal dwellings, their forecast is not part of the NHC responsibilities. This work presents a rapid wave and storm surge warning system based on 3100 synthetic tropical cyclones doing landfall in Mexico. Hydrodynamic and wave models were driven by the synthetic events to create a robust database composed of maximum envelops of wind speed, significant wave height and storm surge for each event. The results were incorporated into a forecast system that uses the NHC advisory to locate the synthetic events passing inside specified radiuses for the present and forecast position of the real event. Using limited computer resources, the system displays the information meeting the search criteria, and the forecaster can select specific events to generate the desired hazard map (i.e. wind, waves, and storm surge) based on the maximum envelop maps. This system was developed in a limited time frame to be operational in 2015 by the National Hurricane and Severe Storms Unit of the Mexican National Weather Service, and represents a pilot project for other countries in the region not covered by detailed storm surge and waves forecasts.

INTEGRATION OF PALSAR AND ASTER SATELLITE DATA FOR GEOLOGICAL MAPPING IN TROPICS

Directory of Open Access Journals (Sweden)

A. Beiranvand Pour

2015-10-01

Full Text Available This research investigates the integration of the Phased Array type L-band Synthetic Aperture Radar (PALSAR and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER satellite data for geological mapping applications in tropical environments. The eastern part of the central belt of peninsular Malaysia has been investigated to identify structural features and mineral mapping using PALSAR and ASTER data. Adaptive local sigma and directional filters were applied to PALSAR data for detecting geological structure elements in the study area. The vegetation, mineralogic and lithologic indices for ASTER bands were tested in tropical climate. Lineaments (fault and fractures and curvilinear (anticline or syncline were detected using PALSAR fused image of directional filters (N-S, NE-SW, and NW-SE.Vegetation index image map show vegetation cover by fusing ASTER VNIR bands. High concentration of clay minerals zone was detected using fused image map derived from ASTER SWIR bands. Fusion of ASTER TIR bands produced image map of the lithological units. Results indicate that data integration and data fusion from PALSAR and ASTER sources enhanced information extraction for geological mapping in tropical environments.

Organismic-Scale Remote Sensing of Canopy Foliar Traits in Lowland Tropical Forests

Directory of Open Access Journals (Sweden)

K. Dana Chadwick

2016-01-01

Full Text Available Airborne high fidelity imaging spectroscopy (HiFIS holds great promise for bridging the gap between field studies of functional diversity, which are spatially limited, and satellite detection of ecosystem properties, which lacks resolution to understand within landscape dynamics. We use Carnegie Airborne Observatory HiFIS data combined with field collected foliar trait data to develop quantitative prediction models of foliar traits at the tree-crown level across over 1000 ha of humid tropical forest. We predicted foliar leaf mass per area (LMA as well as foliar concentrations of nitrogen, phosphorus, calcium, magnesium and potassium for canopy emergent trees (R2: 0.45–0.67, relative RMSE: 11%–14%. Correlations between remotely sensed model coefficients for these foliar traits are similar to those found in laboratory studies, suggesting that the detection of these mineral nutrients is possible through their biochemical stoichiometry. Maps derived from HiFIS provide quantitative foliar trait information across a tropical forest landscape at fine spatial resolution, and along environmental gradients. Multi-nutrient maps implemented at the fine organismic scale will subsequently provide new insight to the functional biogeography and biological diversity of tropical forest ecosystems.

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.

Tropical Pacific Observing for the Next Decade

Science.gov (United States)

Legler, David M.; Hill, Katherine

2014-06-01

More than 60 scientists and program officials from 13 countries met at the Scripps Institution of Oceanography for the Tropical Pacific Observing System (TPOS) 2020 Workshop. The workshop, although motivated in part by the dramatic decline of NOAA's Tropical Atmosphere Ocean (TAO) buoy reporting from mid-2012 to early 2014 (see http://www.bloomberg.com/news/2014-03-07/aging-el-nino-buoys-getting-fixed-as-weather-forecasts-at-risk.html), evaluated the needs for tropical Pacific observing and initiated efforts to develop a more resilient and integrative observing system for the future.

Protected areas in tropical Africa: assessing threats and conservation activities.

Science.gov (United States)

Tranquilli, Sandra; Abedi-Lartey, Michael; Abernethy, Katharine; Amsini, Fidèle; Asamoah, Augustus; Balangtaa, Cletus; Blake, Stephen; Bouanga, Estelle; Breuer, Thomas; Brncic, Terry M; Campbell, Geneviève; Chancellor, Rebecca; Chapman, Colin A; Davenport, Tim R B; Dunn, Andrew; Dupain, Jef; Ekobo, Atanga; Eno-Nku, Manasseh; Etoga, Gilles; Furuichi, Takeshi; Gatti, Sylvain; Ghiurghi, Andrea; Hashimoto, Chie; Hart, John A; Head, Josephine; Hega, Martin; Herbinger, Ilka; Hicks, Thurston C; Holbech, Lars H; Huijbregts, Bas; Kühl, Hjalmar S; Imong, Inaoyom; Yeno, Stephane Le-Duc; Linder, Joshua; Marshall, Phil; Lero, Peter Minasoma; Morgan, David; Mubalama, Leonard; N'Goran, Paul K; Nicholas, Aaron; Nixon, Stuart; Normand, Emmanuelle; Nziguyimpa, Leonidas; Nzooh-Dongmo, Zacharie; Ofori-Amanfo, Richard; Ogunjemite, Babafemi G; Petre, Charles-Albert; Rainey, Hugo J; Regnaut, Sebastien; Robinson, Orume; Rundus, Aaron; Sanz, Crickette M; Okon, David Tiku; Todd, Angelique; Warren, Ymke; Sommer, Volker

2014-01-01

Numerous protected areas (PAs) have been created in Africa to safeguard wildlife and other natural resources. However, significant threats from anthropogenic activities and decline of wildlife populations persist, while conservation efforts in most PAs are still minimal. We assessed the impact level of the most common threats to wildlife within PAs in tropical Africa and the relationship of conservation activities with threat impact level. We collated data on 98 PAs with tropical forest cover from 15 countries across West, Central and East Africa. For this, we assembled information about local threats as well as conservation activities from published and unpublished literature, and questionnaires sent to long-term field workers. We constructed general linear models to test the significance of specific conservation activities in relation to the threat impact level. Subsistence and commercial hunting were identified as the most common direct threats to wildlife and found to be most prevalent in West and Central Africa. Agriculture and logging represented the most common indirect threats, and were most prevalent in West Africa. We found that the long-term presence of conservation activities (such as law enforcement, research and tourism) was associated with lower threat impact levels. Our results highlight deficiencies in the management effectiveness of several PAs across tropical Africa, and conclude that PA management should invest more into conservation activities with long-term duration.

Mangroves among the most carbon-rich forests in the tropics

Science.gov (United States)

Donato, Daniel C.; Kauffman, J. Boone; Murdiyarso, Daniel; Kurnianto, Sofyan; Stidham, Melanie; Kanninen, Markku

2011-05-01

Mangrove forests occur along ocean coastlines throughout the tropics, and support numerous ecosystem services, including fisheries production and nutrient cycling. However, the areal extent of mangrove forests has declined by 30-50% over the past half century as a result of coastal development, aquaculture expansion and over-harvesting. Carbon emissions resulting from mangrove loss are uncertain, owing in part to a lack of broad-scale data on the amount of carbon stored in these ecosystems, particularly below ground. Here, we quantified whole-ecosystem carbon storage by measuring tree and dead wood biomass, soil carbon content, and soil depth in 25 mangrove forests across a broad area of the Indo-Pacific region--spanning 30° of latitude and 73° of longitude--where mangrove area and diversity are greatest. These data indicate that mangroves are among the most carbon-rich forests in the tropics, containing on average 1,023Mg carbon per hectare. Organic-rich soils ranged from 0.5m to more than 3m in depth and accounted for 49-98% of carbon storage in these systems. Combining our data with other published information, we estimate that mangrove deforestation generates emissions of 0.02-0.12Pg carbon per year--as much as around 10% of emissions from deforestation globally, despite accounting for just 0.7% of tropical forest area.

Protected areas in tropical Africa: assessing threats and conservation activities.

Directory of Open Access Journals (Sweden)

Sandra Tranquilli

Full Text Available Numerous protected areas (PAs have been created in Africa to safeguard wildlife and other natural resources. However, significant threats from anthropogenic activities and decline of wildlife populations persist, while conservation efforts in most PAs are still minimal. We assessed the impact level of the most common threats to wildlife within PAs in tropical Africa and the relationship of conservation activities with threat impact level. We collated data on 98 PAs with tropical forest cover from 15 countries across West, Central and East Africa. For this, we assembled information about local threats as well as conservation activities from published and unpublished literature, and questionnaires sent to long-term field workers. We constructed general linear models to test the significance of specific conservation activities in relation to the threat impact level. Subsistence and commercial hunting were identified as the most common direct threats to wildlife and found to be most prevalent in West and Central Africa. Agriculture and logging represented the most common indirect threats, and were most prevalent in West Africa. We found that the long-term presence of conservation activities (such as law enforcement, research and tourism was associated with lower threat impact levels. Our results highlight deficiencies in the management effectiveness of several PAs across tropical Africa, and conclude that PA management should invest more into conservation activities with long-term duration.

Functional traits determine heterospecific use of risk-related social information in forest birds of tropical South-East Asia.

Science.gov (United States)

Hua, Fangyuan; Yong, Ding Li; Janra, Muhammad Nazri; Fitri, Liza M; Prawiradilaga, Dewi; Sieving, Kathryn E

2016-12-01

In birds and mammals, mobbing calls constitute an important form of social information that can attract numerous sympatric species to localized mobbing aggregations. While such a response is thought to reduce the future predation risk for responding species, there is surprisingly little empirical evidence to support this hypothesis. One way to test the link between predation risk reduction and mobbing attraction involves testing the relationship between species' attraction to mobbing calls and the functional traits that define their vulnerability to predation risk. Two important traits known to influence prey vulnerability include relative prey-to-predator body size ratio and the overlap in space use between predator and prey; in combination, these measures strongly influence prey accessibility, and therefore their vulnerability, to predators. Here, we combine community surveys with behavioral experiments of a diverse bird assemblage in the lowland rainforest of Sumatra to test whether the functional traits of body mass (representing body size) and foraging height (representing space use) can predict species' attraction to heterospecific mobbing calls. At four forest sites along a gradient of forest degradation, we characterized the resident bird communities using point count and mist-netting surveys, and determined the species groups attracted to standardized playbacks of mobbing calls produced by five resident bird species of roughly similar body size and foraging height. We found that (1) a large, diverse subcommunity of bird species was attracted to the mobbing calls and (2) responding species (especially the most vigorous respondents) tended to be (a) small (b) mid-storey foragers (c) with similar trait values as the species producing the mobbing calls. Our findings from the relatively lesser known bird assemblages of tropical Asia add to the growing evidence for the ubiquity of heterospecific information networks in animal communities, and provide empirical

Compendium of NASA Data Base for the Global Tropospheric Experiment's Pacific Exploratory Mission-Tropics B (PEM-Tropics B). Volume 1; DC-8

Science.gov (United States)

Scott, A. Donald, Jr.; Kleb, Mary M.; Raper, James L.

2000-01-01

This report provides a compendium of NASA aircraft data that are available from NASA's Global Tropospheric Experiment's (GTE) Pacific Exploratory Mission-Tropics B (PEM-Tropics B) conducted in March and April 1999. PEM-Tropics B was conducted during the southern-tropical wet season when the influence from biomass burning observed in PEM-Tropics A was minimal. Major deployment sites were Hawaii, Kiritimati (Christmas Island), Tahiti, Fiji, and Easter Island. The broad goals of PEM-Tropics B were to improved understanding of the oxidizing power of the atmosphere and the processes controlling sulfur aerosol formation and to establish baseline values for chemical species that are directly coupled to the oxidizing power and aerosol loading of the troposphere. The purpose of this document is to provide a representation of aircraft data that will be available in archived format via NASA Langley's Distributed Active Archive Center (DAAC) or are available through the GTE Project Office archive. The data format is not intended to support original research/analysis, but to assist the reader in identifying data that are of interest.

Spatial and temporal distribution of tropical biomass burning

Science.gov (United States)

Hao, Wei Min; Liu, Mei-Huey

1994-12-01

A database for the spatial and temporal distribution of the amount of biomass burned in tropical America, Africa, and Asia during the late 1970s is presented with a resolution of 5° latitude × 5° longitude. The sources of burning in each grid cell have been quantified. Savanna fires, shifting cultivation, deforestation, fuel wood use, and burning of agricultural residues contribute about 50, 24, 10, 11, and 5%, respectively, of total biomass burned in the tropics. Savanna fires dominate in tropical Africa, and forest fires dominate in tropical Asia. A similar amount of biomass is burned from forest and savanna fires in tropical America. The distribution of biomass burned monthly during the dry season has been derived for each grid cell using the seasonal cycles of surface ozone concentrations. Land use changes during the last decade could have a profound impact on the amount of biomass burned and the amount of trace gases and aerosol particles emitted.

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

Extinction risk escalates in the tropics.

Directory of Open Access Journals (Sweden)

Jana C Vamosi

Full Text Available The latitudinal biodiversity gradient remains one of the most widely recognized yet puzzling patterns in nature. Presently, the high level of extinction of tropical species, referred to as the "tropical biodiversity crisis", has the potential to erode this pattern. While the connection between species richness, extinction, and speciation has long intrigued biologists, these interactions have experienced increased poignancy due to their relevancy to where we should concentrate our conservation efforts. Natural extinction is a phenomenon thought to have its own latitudinal gradient, with lower extinction rates in the tropics being reported in beetles, birds, mammals, and bivalves. Processes that have buffered ecosystems from high extinction rates in the past may also buffer ecosystems against disturbance of anthropogenic origin. While potential parallels between historical and present-day extinction patterns have been acknowledged, they remain only superficially explored and plant extinction patterns have been particularly neglected. Studies on the disappearances of animal species have reached conflicting conclusions, with the rate of extinction appearing either higher or lower in species richness hotspots. Our global study of extinction risk in vascular plants finds disproportionately higher extinction risk in tropical countries, even when indicators of human pressure (GDP, population density, forest cover change are taken into account. Our results are at odds with the notion that the tropics represent a museum of plant biodiversity (places of historically lowered extinction and we discuss mechanisms that may reconcile this apparent contradiction.

Extinction risk escalates in the tropics.

Science.gov (United States)

Vamosi, Jana C; Vamosi, Steven M

2008-01-01

The latitudinal biodiversity gradient remains one of the most widely recognized yet puzzling patterns in nature. Presently, the high level of extinction of tropical species, referred to as the "tropical biodiversity crisis", has the potential to erode this pattern. While the connection between species richness, extinction, and speciation has long intrigued biologists, these interactions have experienced increased poignancy due to their relevancy to where we should concentrate our conservation efforts. Natural extinction is a phenomenon thought to have its own latitudinal gradient, with lower extinction rates in the tropics being reported in beetles, birds, mammals, and bivalves. Processes that have buffered ecosystems from high extinction rates in the past may also buffer ecosystems against disturbance of anthropogenic origin. While potential parallels between historical and present-day extinction patterns have been acknowledged, they remain only superficially explored and plant extinction patterns have been particularly neglected. Studies on the disappearances of animal species have reached conflicting conclusions, with the rate of extinction appearing either higher or lower in species richness hotspots. Our global study of extinction risk in vascular plants finds disproportionately higher extinction risk in tropical countries, even when indicators of human pressure (GDP, population density, forest cover change) are taken into account. Our results are at odds with the notion that the tropics represent a museum of plant biodiversity (places of historically lowered extinction) and we discuss mechanisms that may reconcile this apparent contradiction.

Dry and Semi-Dry Tropical Cyclones

Science.gov (United States)

Cronin, T.; Chavas, D. R.

2017-12-01

Our understanding of dynamics in our real moist atmosphere is strongly informed by idealized dry models. It is widely believed that tropical cyclones (TCs) are an intrinsically moist phenomenon - relying fundamentally on evaporation and latent heat release - yet recent numerical modeling work has found formation of dry axisymmetric tropical cyclones from a state of dry radiative-convective equilibrium. What can such "dry hurricanes" teach us about intensity, structure, and size of real moist tropical cyclones in nature? Are dry TCs even stable in 3D? What about surfaces that are nearly dry but have some latent heat flux - can they also support TCs? To address these questions, we use the SAM cloud-system resolving model to simulate radiative-convective equilibrium on a rapidly rotating f-plane, subject to constant tropospheric radiative cooling. We use a homogeneous surface with fixed temperature and with surface saturation vapor pressure scaled by a factor 0-1 relative to that over pure water - allowing for continuous variation between moist and dry limits. We also explore cases with surface enthalpy fluxes that are uniform in space and time, where partitioning between latent and sensible heat fluxes is specified directly. We find that a completely moist surface yields a TC-world where multiple vortices form spontaneously and persist for tens of days. A completely dry surface can also yield a parallel dry TC-world with many vortices that are even more stable and persistent. Spontaneous cyclogenesis, however, is impeded for a range of low to intermediate surface wetness values, and by the combination of large rotation rates and a dry surface. We discuss whether these constraints on spontaneous cyclogenesis might arise from: 1) rain evaporation in the subcloud layer limiting the range of viable surface wetness values, and 2) a natural convective Rossby number limiting the range of viable rotation rates. Finally, we discuss simulations with uniform surface enthalpy

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.

The future of tropical forests.

Science.gov (United States)

Wright, S Joseph

2010-05-01

Five anthropogenic drivers--land use change, wood extraction, hunting, atmospheric change, climate change--will largely determine the future of tropical forests. The geographic scope and intensity of these five drivers are in flux. Contemporary land use change includes deforestation (approximately 64,000 km(2) yr(-1) for the entire tropical forest biome) and natural forests regenerating on abandoned land (approximately 21,500 km(2) yr(-1) with just 29% of the biome evaluated). Commercial logging is shifting rapidly from Southeast Asia to Africa and South America, but local fuelwood consumption continues to constitute 71% of all wood production. Pantropical rates of net deforestation are declining even as secondary and logged forests increasingly replace old-growth forests. Hunters reduce frugivore, granivore and browser abundances in most forests. This alters seed dispersal, seed and seedling survival, and hence the species composition and spatial template of plant regeneration. Tropical governments have responded to these local threats by protecting 7% of all land for the strict conservation of nature--a commitment that is only matched poleward of 40 degrees S and 70 degrees N. Protected status often fails to stop hunters and is impotent against atmospheric and climate change. There are increasing reports of stark changes in the structure and dynamics of protected tropical forests. Four broad classes of mechanisms might contribute to these changes. Predictions are developed to distinguish among these mechanisms.

Particular characteristics of atopic eczema in tropical environments. The Tropical Environment Control for Chronic Eczema and Molecular Assessment (TECCEMA) cohort study

OpenAIRE

Sánchez, Jorge; Sánchez, Andrés; Cardona, Ricardo

2017-01-01

Abstract: Background: Atopic dermatitis is a prevalent health problem in the world. Allergic sensitization is an important risk factor, but the roles of other factors, inherent in tropic region, are unknown. Objective: A cohort study was designed in a tropical city to investigate molecular and environmental risk factors for eczema, considering as particular features perennial exposure to mites, poor living conditions and others tropical characteristics. Methods: 433 patients were included ...

Identification of dual-tropic HIV-1 using evolved neural networks.

Science.gov (United States)

Fogel, Gary B; Lamers, Susanna L; Liu, Enoch S; Salemi, Marco; McGrath, Michael S

2015-11-01

Blocking the binding of the envelope HIV-1 protein to immune cells is a popular concept for development of anti-HIV therapeutics. R5 HIV-1 binds CCR5, X4 HIV-1 binds CXCR4, and dual-tropic HIV-1 can bind either coreceptor for cellular entry. R5 viruses are associated with early infection and over time can evolve to X4 viruses that are associated with immune failure. Dual-tropic HIV-1 is less studied; however, it represents functional antigenic intermediates during the transition of R5 to X4 viruses. Viral tropism is linked partly to the HIV-1 envelope V3 domain, where the amino acid sequence helps dictate the receptor a particular virus will target; however, using V3 sequence information to identify dual-tropic HIV-1 isolates has remained difficult. Our goal in this study was to elucidate features of dual-tropic HIV-1 isolates that assist in the biological understanding of dual-tropism and develop an approach for their detection. Over 1559 HIV-1 subtype B sequences with known tropisms were analyzed. Each sequence was represented by 73 structural, biochemical and regional features. These features were provided to an evolved neural network classifier and evaluated using balanced and unbalanced data sets. The study resolved R5X4 viruses from R5 with an accuracy of 81.8% and from X4 with an accuracy of 78.8%. The approach also identified a set of V3 features (hydrophobicity, structural and polarity) that are associated with tropism transitions. The ability to distinguish R5X4 isolates will improve computational tropism decisions for R5 vs. X4 and assist in HIV-1 research and drug development efforts. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Tropical Malaysians and temperate Koreans exhibit significant differences in sweating sensitivity in response to iontophoretically administered acetylcholine

Science.gov (United States)

Lee, Jeong-Beom; Bae, Jun-Sang; Matsumoto, Takaaki; Yang, Hun-Mo; Min, Young-Ki

2009-03-01

Natives of the tropics are able to tolerate high ambient temperatures. This results from their long-term residence in hot and often humid tropical climates. This study was designed to compare the peripheral mechanisms of thermal sweating in tropical natives with that of their temperate counterparts. Fifty-five healthy male subjects including 20 native Koreans who live in the temperate Korean climate (Temperate-N) and 35 native tropical Malaysian men that have lived all of their lives in Malaysia (Tropical-N) were enrolled in this study after providing written informed consent to participate. Quantitative sudomotor axon reflex testing after iontophoresis (2 mA for 5 min) with 10% acetylcholine (ACh) was used to determine directly activated (DIR) and axon reflex-mediated (AXR) sweating during ACh iontophoresis. The sweat rate, activated sweat gland density, sweat gland output per single gland activated, and oral and skin temperature changes were measured. The sweat onset time of AXR (nicotinic-receptor-mediated) was 56 s shorter in the Temperate-N than in the Tropical-N subjects ( P < 0.0001). The nicotinic-receptor-mediated sweating activity AXR (1), and the muscarinic-receptor-mediated sweating activity DIR, in terms of sweat volume, were 103% and 59% higher in the Temperate-N compared to the Tropical-N subjects ( P < 0.0001). The Temperate-N group also had a 17.8% ( P < 0.0001) higher active sweat gland density, 35.4% higher sweat output per gland, 0.24°C higher resting oral temperature, and 0.62°C higher resting forearm skin temperature compared to the Tropical-N subjects ( P < 0.01). ACh iontophoresis did not influence oral temperature, but increased skin temperature near where the ACh was administered, in both groups. These results suggest that suppressed thermal sweating in the Tropical-N subjects was, at least in part, due to suppressed sweat gland sensitivity to ACh through both recruitment of active sweat glands and the sweat gland output per each gland

Floristics and biogeography of vegetation in seasonally dry tropical regions

DEFF Research Database (Denmark)

Dexter, K.G.; Smart, B.; Baldauf, C.

2015-01-01

To provide an inter-continental overview of the floristics and biogeography of drought-adapted tropical vegetation formations, we compiled a dataset of inventory plots in South America (n=93), Africa (n=84), and Asia (n=92) from savannas (subject to fire), seasonally dry tropical forests (not...... similar vegetation formations (e.g. savannas) are floristically highly dissimilar. Neotropical moist forest, savanna and seasonally dry tropical forest are floristically distinct, but elsewhere there is no clear floristic division of savanna and seasonally dry tropical forest, though moist and dry...... of the ecology, biology and conservation of savannas and seasonally dry tropical forests may be difficult....

Tropical Journal of Pharmaceutical Research: About this journal

African Journals Online (AJOL)

Tropical Journal of Pharmaceutical Research: About this journal. Journal Home > Tropical Journal of Pharmaceutical Research: About this journal. Log in or Register to get access to full text downloads.

Degradation in carbon stocks near tropical forest edges.

Science.gov (United States)

Chaplin-Kramer, Rebecca; Ramler, Ivan; Sharp, Richard; Haddad, Nick M; Gerber, James S; West, Paul C; Mandle, Lisa; Engstrom, Peder; Baccini, Alessandro; Sim, Sarah; Mueller, Carina; King, Henry

2015-12-18

Carbon stock estimates based on land cover type are critical for informing climate change assessment and landscape management, but field and theoretical evidence indicates that forest fragmentation reduces the amount of carbon stored at forest edges. Here, using remotely sensed pantropical biomass and land cover data sets, we estimate that biomass within the first 500 m of the forest edge is on average 25% lower than in forest interiors and that reductions of 10% extend to 1.5 km from the forest edge. These findings suggest that IPCC Tier 1 methods overestimate carbon stocks in tropical forests by nearly 10%. Proper accounting for degradation at forest edges will inform better landscape and forest management and policies, as well as the assessment of carbon stocks at landscape and national levels.

An empirical framework for tropical cyclone climatology

Energy Technology Data Exchange (ETDEWEB)

Kang, Nam-Young [Korea Meteorological Administration, Seoul (Korea, Republic of); Florida State University, Tallahassee, FL (United States); Elsner, James B. [Florida State University, Tallahassee, FL (United States)

2012-08-15

An empirical approach for analyzing tropical cyclone climate is presented. The approach uses lifetime-maximum wind speed and cyclone frequency to induce two orthogonal variables labeled ''activity'' and ''efficiency of intensity''. The paired variations of activity and efficiency of intensity along with the opponent variations of frequency and intensity configure a framework for evaluating tropical cyclone climate. Although cyclone activity as defined in this framework is highly correlated with the commonly used exponent indices like accumulated cyclone energy, it does not contain cyclone duration. Empirical quantiles are used to determine threshold intensity levels, and variant year ranges are used to find consistent trends in tropical cyclone climatology. In the western North Pacific, cyclone activity is decreasing despite increases in lifetime-maximum intensity. This is due to overwhelming decreases in cyclone frequency. These changes are also explained by an increasing efficiency of intensity. The North Atlantic shows different behavior. Cyclone activity is increasing due to increasing frequency and, to a lesser extent, increasing intensity. These changes are also explained by a decreasing efficiency of intensity. Tropical cyclone trends over the North Atlantic basin are more consistent over different year ranges than tropical cyclone trends over the western North Pacific. (orig.)

First record of the blacktip reef shark Carcharhinus melanopterus (Carcharhiniformes: Carcharhinidae from the Tropical Eastern Pacific

Directory of Open Access Journals (Sweden)

Andrés López-Garro

2012-11-01

Full Text Available The blacktip reef shark Carcharhinus melanopterus, is one of the most common Indo-Pacific reef sharks. On April 29, 2012, a juvenile male blacktip reef shark measuring 89 cm total length (TL, was incidentally caught during a research expedition in Chatham Bay, Isla del Coco National Park, Costa Rica, located in the Tropical Eastern Pacific. This is the first record of the species from Isla del Coco National Park, Costa Rica, and from the Tropical Eastern Pacific.El tiburón punta negra de arrecife, Carcharhinus melanopterus, es uno de los tiburones de arrecife más comunes del Indo-Pacífico. Durante una expedición científica al Parque Nacional Isla del Coco, Costa Rica, Pacífico Tropical Oriental, un tiburón punta negra de arrecife fue capturado en Bahía Chatham, Parque Nacional Isla del Coco, el 29 de abril 2012. El espécimen capturado era un macho juvenil de 89 cm. Este es el primer informe de esta especie para el Parque Nacional Isla del Coco, Costa Rica y para el Pacífico Tropical Oriental.

7 CFR 1437.505 - Application for payment for the tropical region.

Science.gov (United States)

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Application for payment for the tropical region. 1437... DISASTER ASSISTANCE PROGRAM Determining Coverage in the Tropical Region § 1437.505 Application for payment for the tropical region. (a) For producers of covered tropical crops in Guam, Virgin Islands, American...

Chapter 50: history of tropical neurology.

Science.gov (United States)

Ogunniyi, Adesola

2010-01-01

Tropical neurology began less than two centuries ago. Consumption of dietary toxins predominated at the beginning and gave birth to the geographic entity. The story moved from lathyrism through Jamaican neuropathy to cassava-induced epidemic neuropathy, which was contrasted with Konzo, also associated with cassava. Other tropical diseases enumerated with chronological details include: Chaga's diseases, kwashiorkor, Madras type of motor neuron disease, atlanto-axial dislocation, Burkitt's lymphoma and Kuru, associated with cannibalism among the Fore linguistic group in New Guinea. More recent documentation includes the Cuban neuropathy in 1991 with an epidemic of visual loss and neuropathy, Anaphe venata entomophagy in Nigeria presenting as seasonal ataxia, and neurological aspects of the human immunodeficiency virus infection complete the picture. With time, professional associations were formed and the pioneers were given prominence. The World Federation of Neurology featured Geographic Neurology as a theme in 1977 and Tropical Neurology was given prominence at its 1989 meeting in New Delhi, India. The situation remains unchanged with regards to rare diseases like Meniere's, multiple sclerosis, hereditary disorders. However, with westernization and continued urbanization, changing disease patterns are being observed and tropical neurology may depart from dietary toxins to more western world-type disorders.

Tropics accelerate the evolution of hybrid male sterility in Drosophila.

Science.gov (United States)

Yukilevich, Roman

2013-06-01

Understanding the evolutionary mechanisms that facilitate speciation and explain global patterns of species diversity has remained a challenge for decades. The most general pattern of species biodiversity is the latitudinal gradient, whereby species richness increases toward the tropics. Although such a global pattern probably has a multitude of causes, recent attention has focused on the hypothesis that speciation and the evolution of reproductive isolation occur faster in the tropics. Here, I tested this prediction using a dataset on premating and postzygotic isolation between recently diverged Drosophila species. Results showed that while the evolution of premating isolation was not greater between tropical Drosophila relative to nontropical species, postzygotic isolation evolved faster in the tropics. In particular, hybrid male sterility was much greater among tropical Drosophila compared to nontropical species pairs of similar genetic age. Several testable explanations for the novel pattern are discussed, including greater role for sterility-inducing bacterial endosymbionts in the tropics and more intense sperm-sperm competition or sperm-egg sexual conflict in the tropics. The results imply that processes of speciation in the tropics may evolve at different rates or may even be somewhat different from those at higher latitudes. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

A biogeographical study on tropical flora of southern China.

Science.gov (United States)

Zhu, Hua

2017-12-01

The tropical climate in China exists in southeastern Xizang (Tibet), southwestern to southeastern Yunnan, southwestern Guangxi, southern Guangdon, southern Taiwan, and Hainan, and these southern Chinese areas contain tropical floras. I checked and synonymized native seed plants from these tropical areas in China and recognized 12,844 species of seed plants included in 2,181 genera and 227 families. In the tropical flora of southern China, the families are mainly distributed in tropical areas and extend into temperate zones and contribute to the majority of the taxa present. The genera with tropical distributions also make up the most of the total flora. In terms of geographical elements, the genera with tropical Asian distribution constitute the highest proportion, which implies tropical Asian or Indo-Malaysia affinity. Floristic composition and geographical elements are conspicuous from region to region due to different geological history and ecological environments, although floristic similarities from these regions are more than 90% and 64% at the family and generic levels, respectively, but lower than 50% at specific level. These differences in the regional floras could be influenced by historical events associated with the uplift of the Himalayas, such as the southeastward extrusion of the Indochina geoblock, clockwise rotation and southeastward movement of Lanping-Simao geoblock, and southeastward movement of Hainan Island. The similarity coefficients between the flora of southern China and those of Indochina countries are more than 96% and 80% at family and generic levels, indicating their close floristic affinity and inclusion in the same biogeographically floristic unit.

Biogenic VOC Emissions from Tropical Landscapes

Science.gov (United States)

Guenther, A.; Greenberg, J.; Harley, P.; Otter, L.; Vanni Gatti, L.; Baker, B.

2003-04-01

Biogenic VOC have an important role in determining the chemical composition of atmosphere. As a result, these compounds are important for visibility, biogeochemical cycling, climate and radiative forcing, and the health of the biosphere. Tropical landscapes are estimated to release about 80% of total global biogenic VOC emissions but have been investigated to lesser extent than temperate regions. Tropical VOC emissions are particularly important due to the strong vertical transport and the rapid landuse change that is occurring there. This presentation will provide an overview of field measurements of biogenic VOC emissions from tropical landscapes in Amazonia (Large-scale Biosphere-atmosphere experiment in Amazonia, LBA) Central (EXPRESSO) and Southern (SAFARI 2000) Africa, Asia and Central America. Flux measurement methods include leaf-scale (enclosure measurements), canopy-scale (above canopy tower measurements), landscape-scale (tethered balloon), and regional-scale (aircraft measurements) observations. Typical midday isoprene emission rates for different landscapes vary by more than a factor of 20 with the lowest emissions observed from degraded forests. Emissions of alpha-pinene vary by a similar amount with the highest emissions associated with landscapes dominated by light dependent monoterpene emitting plants. Isoprene emissions tend to be higher for neotropical forests (Amazon and Costa Rica) in comparison to Africa and Asian tropical forests but considerable differences are observed within regions. Strong seasonal variations were observed in both the Congo and the Amazon rainforests with peak emissions during the dry seasons. Substantial emissions of light dependent monoterpenes, methanol and acetone are characteristic of at least some tropical landscapes.

Compendium of NASA Data Base for the Global Tropospheric Experiment's Pacific Exploratory Mission - Tropics B (PEM-Tropics B). Volume 2; P-3B

Science.gov (United States)

Scott, A. Donald, Jr.; Kleb, Mary M.; Raper, James L.

2000-01-01

This report provides a compendium of NASA aircraft data that are available from NASA's Global Tropospheric Experiment's (GTE) Pacific Exploratory Mission-Tropics B (PEM-Tropics B) conducted in March and April 1999. PEM-Tropics B was conducted during the southern-tropical wet season when the influence from biomass burning observed in PEM-Tropics A was minimal. Major deployment sites were Hawaii, Kiritimati (Christmas Island), Tahiti, Fiji, and Easter Island. The broad goals of PEM-Tropics B were to improved understanding of the oxidizing power of the atmosphere and the processes controlling sulfur aerosol formation and to establish baseline values for chemical species that are directly coupled to the oxidizing power and aerosol loading of the troposphere. The purpose of this document is to provide a representation of aircraft data that will be available in archived format via NASA Langley's Distributed Active Archive Center (DAAC) or are available through the GTE Project Office archive. The data format is not intended to support original research/analysis, but to assist the reader in identifying data that are of interest.

Tropical Rainfall Measuring Mission: Monitoring the Global Tropics for 3 Years and Beyond. 1.1

Science.gov (United States)

Shepherd, Marshall; Starr, David OC. (Technical Monitor)

2001-01-01

The Tropical Rainfall Measuring Mission (TRMM) was launched in November 1997 as a joint U.S.-Japanese mission to advance understanding of the global energy and water cycle by providing distributions of rainfall and latent heating over the global tropics. As a part of NASA's Earth System Enterprise, TRMM seeks to understand the mechanisms through which changes in tropical rainfall influence global circulation. Additionally, a goal is to improve the ability to model these processes in order to predict global circulations and rainfall variability at monthly and longer time scales. Such understanding has implications for assessing climate processes related to El Nino/La Nina and Global Warming. TRMM has also provided unexpected and exciting new knowledge and applications in areas related to hurricane monitoring, lightning, pollution, hydrology, and other areas. This CD-ROM includes a self-contained PowerPoint presentation that provides an overview of TRMM and significant science results; a set of data movies or animation; and listings of current TRMM-related publications in the literature.

Partnerships in global health and collaborative governance: lessons learnt from the Division of Tropical and Humanitarian Medicine at the Geneva University Hospitals.

Science.gov (United States)

Beran, David; Aebischer Perone, Sigiriya; Alcoba, Gabriel; Bischoff, Alexandre; Bussien, Claire-Lise; Eperon, Gilles; Hagon, Olivier; Heller, Olivia; Jacquerioz Bausch, Frédérique; Perone, Nicolas; Vogel, Thomas; Chappuis, François

2016-04-29

In 2007 the "Crisp Report" on international partnerships increased interest in Northern countries on the way their links with Southern partners operated. Since its establishment in 2007 the Division of Tropical and Humanitarian Medicine at the Geneva University Hospitals has developed a variety of partnerships. Frameworks to assess these partnerships are needed and recent attention in the field of public management on collaborative governance may provide a useful approach for analyzing international collaborations. Projects of the Division of Tropical and Humanitarian Medicine were analyzed by collaborators within the Division using the model proposed by Emerson and colleagues for collaborative governance, which comprises different components that assess the collaborative process. International projects within the Division of Tropical and Humanitarian Medicine can be divided into four categories: Human resource development; Humanitarian response; Neglected Tropical Diseases and Noncommunicable diseases. For each of these projects there was a clear leader from the Division of Tropical and Humanitarian Medicine as well as a local counterpart. These individuals were seen as leaders both due to their role in establishing the collaboration as well as their technical expertise. Across these projects the actual partners vary greatly. This diversity means a wide range of contributions to the collaboration, but also complexity in managing different interests. A common definition of the collaborative aims in each of the projects is both a formal and informal process. Legal, financial and administrative aspects of the collaboration are the formal elements. These can be a challenge based on different administrative requirements. Friendship is part of the informal aspects and helps contribute to a relationship that is not exclusively professional. Using collaborative governance allows the complexity of managing partnerships to be presented. The framework used highlights the

Design basis tropical cyclone for nuclear power plants

International Nuclear Information System (INIS)

1984-01-01

The general characteristics of tropical cyclones are discussed in this Safety Guide, with particular emphasis on their pressure and wind structures in the light of available data. General methods are given for the evaluation of the relevant parameters of a Probable Maximum Tropical Cyclone (PMTC), which can be used as the Design Basis Tropical Cyclone (DBTC); these parameters then serve as inputs for the derivation of a design basis surge and a design basis wind. A possible method is also given for the evaluation of the PMTC pressure and wind field based on an approach valid primarily for a particular region. This method depends on the results of a theoretical study on the tropical cyclone structure and makes use of a large amount of data, including aircraft reconnaissance observations for 170 most intense tropical cyclones near the coast of Japan, Taiwan and the Philippines for the period 1960-1974, as well as detailed analyses of all the extreme storms along the Gulf of Mexico and the east coast of the USA during 1900-1978, for the determination of the necessary parameters

Agro-Science Journal of Tropical Agriculture, Food, Environment ...

African Journals Online (AJOL)

OLUWOLE AKINNAGBE

2009-09-03

Sep 3, 2009 ... Agro-Science Journal of Tropical Agriculture, Food, Environment and Extension. Volume 8 ... 3 International Institute of Tropical Agriculture, High Rainfall Station,. Onne, Rivers State ...... Biosciences proceedings. 6: 444-454.

A global historical data set of tropical cyclone exposure (TCE-DAT)

Science.gov (United States)

Geiger, Tobias; Frieler, Katja; Bresch, David N.

2018-01-01

Tropical cyclones pose a major risk to societies worldwide, with about 22 million directly affected people and damages of USD 29 billion on average per year over the last 20 years. While data on observed cyclones tracks (location of the center) and wind speeds are publicly available, these data sets do not contain information about the spatial extent of the storm and people or assets exposed. Here, we apply a simplified wind field model to estimate the areas exposed to wind speeds above 34, 64, and 96 knots (kn). Based on available spatially explicit data on population densities and gross domestic product (GDP) we estimate (1) the number of people and (2) the sum of assets exposed to wind speeds above these thresholds accounting for temporal changes in historical distribution of population and assets (TCE-hist) and assuming fixed 2015 patterns (TCE-2015). The associated spatially explicit and aggregated country-event-level exposure data (TCE-DAT) cover the period 1950 to 2015 and are freely available at https://doi.org/10.5880/pik.2017.011 (Geiger at al., 2017c). It is considered key information to (1) assess the contribution of climatological versus socioeconomic drivers of changes in exposure to tropical cyclones, (2) estimate changes in vulnerability from the difference in exposure and reported damages and calibrate associated damage functions, and (3) build improved exposure-based predictors to estimate higher-level societal impacts such as long-term effects on GDP, employment, or migration. We validate the adequateness of our methodology by comparing our exposure estimate to estimated exposure obtained from reported wind fields available since 1988 for the United States. We expect that the free availability of the underlying model and TCE-DAT will make research on tropical cyclone risks more accessible to non-experts and stakeholders.

Estimation of leaf area in tropical maize

NARCIS (Netherlands)

Elings, A.

2000-01-01

Leaf area development of six tropical maize cultivars grown in 1995 and 1996 in several tropical environments in Mexico (both favourable and moisture-and N-limited) was observed and analysed. First, the validity of a bell-shaped curve describing the area of individual leaves as a function of leaf

Sex-specific differences in transcriptome profiles of brain and muscle tissue of the tropical gar.

Science.gov (United States)

Cribbin, Kayla M; Quackenbush, Corey R; Taylor, Kyle; Arias-Rodriguez, Lenin; Kelley, Joanna L

2017-04-07

The tropical gar (Atractosteus tropicus) is the southernmost species of the seven extant species of gar fishes in the world. In Mexico and Central America, the species is an important food source due to its nutritional quality and low price. Despite its regional importance and increasing concerns about overexploitation and habitat degradation, basic genetic information on the tropical gar is lacking. Determining genetic information on the tropical gar is important for the sustainable management of wild populations, implementation of best practices in aquaculture settings, evolutionary studies of ancient lineages, and an understanding of sex-specific gene expression. In this study, the transcriptome of the tropical gar was sequenced and assembled de novo using tissues from three males and three females using Illumina sequencing technology. Sex-specific and highly differentially expressed transcripts in brain and muscle tissues between adult males and females were subsequently identified. The transcriptome was assembled de novo resulting in 80,611 transcripts with a contig N50 of 3,355 base pairs and over 168 kilobases in total length. Male muscle, brain, and gonad as well as female muscle and brain were included in the assembly. The assembled transcriptome was annotated to identify the putative function of expressed transcripts using Trinotate and SwissProt, a database of well-annotated proteins. The brain and muscle datasets were then aligned to the assembled transcriptome to identify transcripts that were differentially expressed between males and females. The contrast between male and female brain identified 109 transcripts from 106 genes that were significantly differentially expressed. In the muscle comparison, 82 transcripts from 80 genes were identified with evidence for significant differential expression. Almost all genes identified as differentially expressed were sex-specific. The differentially expressed transcripts were enriched for genes involved in

Where are the tropical plants? A call for better inclusion of tropical plants in studies investigating and predicting the effects of climate change

Directory of Open Access Journals (Sweden)

Kenneth J Feeley

2016-01-01

Full Text Available Tropical plant species are systematically underrepresented in large-scale analyses or synthesis looking at the potential effects of global climate change.  The reason being that we simply don’t know enough about the distributions and ecologies of most tropical plant species to predict their fate under climate change. This gaping hole in our knowledge is extremely worrisome given the high diversity of tropical plants, the crucial roles that they play in supporting global diversity and ecosystem function, and the elevated threats that climate change may pose to tropical species in general.  

Tropical wetlands, climate, and land-use change: adaptation and mitigation opportunities

Science.gov (United States)

Randy Kolka; D. Murdiyarso; J. B. Kauffman; Richard Birdsey

2016-01-01

Tropical wetland ecosystems, especially mangroves and peatlands, are carbon (C) rich ecosystems. Globally, tropical mangroves store about 20 PgC, however, deforestation has contributed 10 % of the total global emissions from tropical deforestation, even though mangroves account for only about 0.7 % of the world’s tropical forest area (Donato et al. 2011). Meanwhile,...

Mercury in tropical and subtropical coastal environments

Science.gov (United States)

Costa, Monica F.; Landing, William M.; Kehrig, Helena A.; Barletta, Mário; Holmes, Christopher D.; Barrocas, Paulo R. G.; Evers, David C.; Buck, David G.; Vasconcellos, Ana Claudia; Hacon, Sandra S.; Moreira, Josino C.; Malm, Olaf

2012-01-01

Anthropogenic activities influence the biogeochemical cycles of mercury, both qualitatively and quantitatively, on a global scale from sources to sinks. Anthropogenic processes that alter the temporal and spatial patterns of sources and cycling processes are changing the impacts of mercury contamination on aquatic biota and humans. Human exposure to mercury is dominated by the consumption of fish and products from aquaculture operations. The risk to society and to ecosystems from mercury contamination is growing, and it is important to monitor these expanding risks. However, the extent and manner to which anthropogenic activities will alter mercury sources and biogeochemical cycling in tropical and sub-tropical coastal environments is poorly understood. Factors as (1) lack of reliable local/regional data; (2) rapidly changing environmental conditions; (3) governmental priorities and; (4) technical actions from supra-national institutions, are some of the obstacles to overcome in mercury cycling research and policy formulation. In the tropics and sub-tropics, research on mercury in the environment is moving from an exploratory “inventory” phase towards more process-oriented studies. Addressing biodiversity conservation and human health issues related to mercury contamination of river basins and tropical coastal environments are an integral part of paragraph 221 paragraph of the United Nations document “The Future We Want” issued in Rio de Janeiro in June 2012. PMID:22901765

Oceanic migration behaviour of tropical Pacific eels from Vanuatu

DEFF Research Database (Denmark)

Schabetsberger, R; Økland, F; Aarestrup, K

2013-01-01

Information on oceanic migrations and spawning areas of tropical Pacific freshwater eels (genus Anguilla) is very limited. Lake Letas and its single outflowing river, Mbe Solomul on Gaua Island, Vanuatu, were surveyed for large migrating individuals. Twenty-four Anguilla marmorata (87 to 142 cm),...... impact of the lunar cycle on the upper limit of migration depths was found in A. marmorata (full moon: 230 m, new moon: 170 m). These behaviours may be explained as a trade-off between predator avoidance and the necessity to maintain a sufficiently high metabolism for migration....

Topic 2.0: Tropical cyclone formation and extratropical transition

OpenAIRE

Harr, Patrick A.

2010-01-01

Approved for public release; distribution is unlimited In this section, progress since ITWC-VI on research, observations and forecasting of tropical cyclone formation and extratropical transition is summarized. While tropical cyclone formation and extratropical transition are stages at opposite ends of the tropical cyclone lifecycle, significant lack of understanding remains in relation to processes associated with each stage. Formation and extratropical transition involve interactions a...

Inferring genetic parameters of lactation in Tropical Milking Criollo cattle with random regression test-day models.

Science.gov (United States)

Santellano-Estrada, E; Becerril-Pérez, C M; de Alba, J; Chang, Y M; Gianola, D; Torres-Hernández, G; Ramírez-Valverde, R

2008-11-01

This study inferred genetic and permanent environmental variation of milk yield in Tropical Milking Criollo cattle and compared 5 random regression test-day models using Wilmink's function and Legendre polynomials. Data consisted of 15,377 test-day records from 467 Tropical Milking Criollo cows that calved between 1974 and 2006 in the tropical lowlands of the Gulf Coast of Mexico and in southern Nicaragua. Estimated heritabilities of test-day milk yields ranged from 0.18 to 0.45, and repeatabilities ranged from 0.35 to 0.68 for the period spanning from 6 to 400 d in milk. Genetic correlation between days in milk 10 and 400 was around 0.50 but greater than 0.90 for most pairs of test days. The model that used first-order Legendre polynomials for additive genetic effects and second-order Legendre polynomials for permanent environmental effects gave the smallest residual variance and was also favored by the Akaike information criterion and likelihood ratio tests.

Trade, tropical deforestation and policy interventions

International Nuclear Information System (INIS)

Barbier, E.B.; Rauscher, M.

1992-01-01

This paper examines several aspects of the links between the trade in tropical timber and deforestation from the perspective of an exporting country. The various versions of the model developed here have highlighted a number of important features of this linkage. First, if the producer country values its tropical forest solely as a source of timber export earnings then it will aim for a smaller forest stock in the long run than if it also considers the other values provided by the forest. Second, if importing nations want the exporting countries to conserve more of their forests, trade interventions appear to be second-best way of achieving this result. Third, increased market power by a large country exporter or group of exporters may actually lead to greater forest conservation. Finally, the existence of a foreign capital market may further ensure that the tropical timber country may conserve its forest stock in the long run. Several recent reviews of global forest sector policies have discussed implications similar to those analyzed theoretically in our model. Generally, the same conclusions have been reached. However, what is of increasing concern is that domestic market and policy failures within tropical forest countries continue to distort the incentives for more sustainable management of timber production and efficient development of processing capacity, while at the same time the international community increasingly contemplates the use of bans, tariffs and other trade measures to discourage 'unsustainable' tropical timber exploitation. As our paper has attempted to show, sometimes the more simple solutions lead neither to a straightforward, nor to the desired, results. 18 refs, 1 fig

An efficient DNA isolation method for tropical plants

African Journals Online (AJOL)

walkinnet

2013-05-08

May 8, 2013 ... 2Key Laboratory of Biology and Genetic Resources of Tropical Crops, Ministry of Agriculture, P. R. ... yielded high-quality DNA from 10 tropical plants including cassava, rubber tree, banana, etc. ..... Major Projects (GrantNo.

Resolving Tropical Cyclone Intensity in Models

Science.gov (United States)

Davis, C. A.

2018-02-01

In recent years, global weather forecast models and global climate models have begun to depict intense tropical cyclones, even up to category 5 on the Saffir-Simpson scale. In light of the limitation of horizontal resolution in such models, the author performs calculations, using the extended Best Track data for Atlantic tropical cyclones, to estimate the ability of models with differing grid spacing to represent Atlantic tropical cyclone intensity statistically. Results indicate that, under optimistic assumptions, models with horizontal grid spacing of one fourth degree or coarser should not produce a realistic number of category 4 and 5 storms unless there are errors in spatial attributes of the wind field. Furthermore, the case of Irma (2017) is used to demonstrate the importance of a realistic depiction of angular momentum and to motivate the use of angular momentum in model evaluation.

Infectious Diseases and Tropical Cyclones in Southeast China.

Science.gov (United States)

Zheng, Jietao; Han, Weixiao; Jiang, Baofa; Ma, Wei; Zhang, Ying

2017-05-07

Southeast China is frequently hit by tropical cyclones (TCs) with significant economic and health burdens each year. However, there is a lack of understanding of what infectious diseases could be affected by tropical cyclones. This study aimed to examine the impacts of tropical cyclones on notifiable infectious diseases in southeast China. Disease data between 2005 and 2011 from four coastal provinces in southeast China, including Guangdong, Hainan, Zhejiang, and Fujian province, were collected. Numbers of cases of 14 infectious diseases were compared between risk periods and reference periods for each tropical cyclone. Risk ratios (RR s ) were calculated to estimate the risks. TCs were more likely to increase the risk of bacillary dysentery, paratyphoid fever, dengue fever and acute hemorrhagic conjunctivitis ( ps infectious diseases. TCs are more likely to increase the risk of intestinal and contact transmitted infectious diseases than to decrease the risk, and more likely to decrease the risk of respiratory infectious diseases than to increase the risk. Findings of this study would assist in developing public health strategies and interventions for the reduction of the adverse health impacts from tropical cyclones.

Community ecology of tropical forest snails: 30 years after Solem

NARCIS (Netherlands)

Schilthuizen, M.

2011-01-01

Since Solem’s provocative claim in the early 1980s that land snails in tropical forests are neither abundant nor diverse, at least 30 quantitative-ecological papers on tropical land snail communities have appeared. Jointly, these papers have shown that site diversity is, in fact, high in tropical

Prospects and Challenges in tropical isotope dendroclimatology

Science.gov (United States)

Evans, M. N.; Anchukaitis, K. J.; White, S. R.; Ektvedt, T. M.; Penniston, R. C.; Rheaume, M. M.; Bowman, D. M.

2008-12-01

We review a stable isotope-based approach to the development, modeling, interpretation, and analysis of hydrometeorological estimates from tropical trees. The strategy overcomes the common problem of missing, intermittent or non-annual ring structure in tropical trees by relying instead on the observation of the annual wet-dry seasonality typical to tropical environments as mirrored in the oxygen isotopic composition of wood-derived α-cellulose. We explore regions for which forward modeling of the proxy system would expect us to resolve hydrometeorological variations associated with the El Niño-Southern Oscillation (ENSO) phenomenon, rather than being limited to regions with tree species or environments producing verifiable annual ring chronologies. A modified protocol allows for rapid, simple and non-toxic micro-extraction of pure α-cellulose, which is isotopically indistinguishable from that produced by more classical means. We describe a new reactor for the pyrolysis of α-cellulose in an induction heater, which permits isotopic analysis of α-cellulose samples as small as 30μg, and as many as 100 automated sample analyses per day. A forward model adapted for tropical environments can be used to test and refine the interpretation of the isotopic data, and to predict locales for which we should be able to maximize the paleoclimatic potential of future sample collections. We have found the modeled isotopic chronometer and raingage in agreement with independent chronological controls in a variety of environments and tree species in Costa Rica, Indonesia, Brazil, Peru and Australia. Development of long hydrometeorological records from the terrestrial tropics is underway not only by our group, but by a growing number of collaborators and colleagues. Together we should be able to build a network of paleoprecipitation records and better understand the linkages between tropical surface ocean temperatures and large-scale drought.

Interactions of the tropical oceans. Rev.ed.

International Nuclear Information System (INIS)

Latif, M.; Barnett, T.P.

1994-01-01

We have investigated the interactions of the tropical oceans on interannual time scales by conducting a series of uncoupled atmospheric and oceanic general circulation experiments and hybrid coupled model simulations. Our results illustrate the key role of the El Nino/Southern Oscillation (ENSO) phenomenon in generating interannual variability in all three tropical ocean basins. Sea surface temperature (SST) anomalies in the tropical Pacific force via a changed atmospheric circulation SST anomalies of the same sign in the Indian Ocean and SST anomalies of the opposite sign in the Atlantic. However, although air-sea interactions in the Indian and Atlantic Oceans are much weaker than those in the Pacific, they contribute significantly to the variability in these two regions. The role of these air-sea interactions is mainly that of an amplifyer by which the ENSO induced signals are enhanced in ocean and atmosphere. This process is particularly important in the tropical Atlantic region. We investigated also whether ENSO is part of a zonally propagating ''wave'' which travels around the globe with a time scale of several years. Consistent with observations, the upper ocean heat content in the various numerical simulations seems to propagate slowly around the globe. SST anomalies in the Pacific Ocean introduce a global atmospheric response which in turn forces variations in the other tropical oceans. Since the different oceans exhibit different response characteristics to low-frequency wind changes, the individual tropical ocean responses can add up coincidentally to look like a global wave, and that appears to be the situation. In particular, no evidence is found that the Indian Ocean can significantly affect the ENSO cycle in the Pacific. Finally, the potential for climate forecasts in the Indian and Atlantic Oceans appears to be enhanced if one includes, in a coupled way, remote influences from the Pacific. (orig.)

Tropical pyomyositis: imaging findings and a review of the literature

International Nuclear Information System (INIS)

Pretorius, E.S.; Hruban, R.H.; Fishman, E.K.

1996-01-01

Tropical pyomyositis is a rare cause of multiple abscesses of skeletal muscle. The entity is rare in temperate climates and, as its name suggests, is more common in areas such as the tropics and South Pacific. Staphylococcus aureus is the most common cause of infection. Therapy is aggressive, with surgical debridement and drainage followed by antibiotics. We report an unusual case of tropical myositis which simulated tumor recurrence in a patient without the typical risk factors associated with tropical pyomyositis. (orig.). With 3 figs

Tropical pyomyositis: imaging findings and a review of the literature

Energy Technology Data Exchange (ETDEWEB)

Pretorius, E.S. [Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Medical Institutions, 600 N. Wolfe Street, Baltimore, MD 21287 (United States); Hruban, R.H. [Department of Pathology, The Johns Hopkins Medical Institutions, Baltimore, Maryland (United States); Fishman, E.K. [Russell H. Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins Medical Institutions, 600 N. Wolfe Street, Baltimore, MD 21287 (United States)

1996-08-01

Tropical pyomyositis is a rare cause of multiple abscesses of skeletal muscle. The entity is rare in temperate climates and, as its name suggests, is more common in areas such as the tropics and South Pacific. Staphylococcus aureus is the most common cause of infection. Therapy is aggressive, with surgical debridement and drainage followed by antibiotics. We report an unusual case of tropical myositis which simulated tumor recurrence in a patient without the typical risk factors associated with tropical pyomyositis. (orig.). With 3 figs.

Agricultural expansion and its impacts on tropical nature.

Science.gov (United States)

Laurance, William F; Sayer, Jeffrey; Cassman, Kenneth G

2014-02-01

The human population is projected to reach 11 billion this century, with the greatest increases in tropical developing nations. This growth, in concert with rising per-capita consumption, will require large increases in food and biofuel production. How will these megatrends affect tropical terrestrial and aquatic ecosystems and biodiversity? We foresee (i) major expansion and intensification of tropical agriculture, especially in Sub-Saharan Africa and South America; (ii) continuing rapid loss and alteration of tropical old-growth forests, woodlands, and semi-arid environments; (iii) a pivotal role for new roadways in determining the spatial extent of agriculture; and (iv) intensified conflicts between food production and nature conservation. Key priorities are to improve technologies and policies that promote more ecologically efficient food production while optimizing the allocation of lands to conservation and agriculture. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bioquality Hotspots in the Tropical African Flora.

Science.gov (United States)

Marshall, Cicely A M; Wieringa, Jan J; Hawthorne, William D

2016-12-05

Identifying areas of high biodiversity is an established way to prioritize areas for conservation [1-3], but global approaches have been criticized for failing to render global biodiversity value at a scale suitable for local management [4-6]. We assembled 3.1 million species distribution records for 40,401 vascular plant species of tropical Africa from sources including plot data, herbarium databases, checklists, and the Global Biodiversity Information Facility (GBIF) and cleaned the records for geographic accuracy and taxonomic consistency. We summarized the global ranges of tropical African plant species into four weighted categories of global rarity called Stars. We applied the Star weights to summaries of species distribution data at fine resolutions to map the bioquality (range-restricted global endemism) of areas [7]. We generated confidence intervals around bioquality scores to account for the remaining uncertainty in the species inventory. We confirm the broad significance of the Horn of Africa, Guinean forests, coastal forests of East Africa, and Afromontane regions for plant biodiversity but also reveal the variation in bioquality within these broad regions and others, particularly at local scales. Our framework offers practitioners a quantitative, scalable, and replicable approach for measuring the irreplaceability of particular local areas for global biodiversity conservation and comparing those areas within their global and regional context. Copyright © 2016 Elsevier Ltd. All rights reserved.

Historical North Atlantic Tropical Cyclone Tracks 1851-2005, Geographic NAD83, NOAA (2006) [atlantic_hurricane_tracks_1851_2005_NOAA_2006

Data.gov (United States)

Louisiana Geographic Information Center — This Historical North Atlantic Tropical Cyclone Tracks file contains the 6-hourly (0000, 0600, 1200, 1800 UTC) center locations and intensities for all subtropical...

Water vapor stable isotope observations from tropical Australia

KAUST Repository

Parkes, Stephen; Deutscher, Nicholas; Griffith, David; McCabe, Matthew

2015-01-01

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

Development Mode and Recommendations for Industrialization of Tropical Agricultural Science and Technology

OpenAIRE

QIU, Meihuan; LIN, Minxia; ZHANG, Xiaodong; ZHANG, Hongyi; WANG, Zhunian

2014-01-01

Industrialization of tropical agricultural science and technology is an essential part of tropical agricultural technological innovation. This paper firstly analyzed development mode of industrialization of tropical agricultural science and technology in Chin and then came up with recommendations for developing industrialization of tropical agricultural science and technology.

Supplementation of dairy weaners grazing tropical pastures

African Journals Online (AJOL)

tropical pastures for growth of dairy replacement heifers, and to assess the need for ... restricted by intake of digestible nutrients. Tropical pastures ... 1983, 13(l). Table 1 Effect of rnaize or maize plus cotton seed meal on the growth of weaner calves. Level. Wean wt wean ro ll0 kg ll0- 130 kg. Wean ro 130 kg. Supplements.

Tropical diabetic hand syndrome: a case report.

Science.gov (United States)

Yeika, Eugene Vernyuy; Tchoumi Tantchou, Jacques Cabral; Foryoung, Joyce Bei; Tolefac, Paul Nkemtendong; Efie, Derrick Tembi; Choukem, Siméon Pierre

2017-02-13

Tropical diabetic hand syndrome describes a complex hand sepsis affecting patients with diabetes across the tropics and often results from a trivial hand trauma. The clinical presentation of this syndrome is variable and ranges from localised swelling and cellulitis, with or without ulceration of the hand to progressive fulminant hand sepsis, and gangrene affecting the entire limb which may be fatal. Tropical diabetic hand syndrome could lead to permanent disability and death as a result of delay in presentation, late diagnosis and late medical and surgical intervention. This indexed case acts as an eye opener for physicians to the existence of this hand sepsis. We report the case of a 57 year-old black African female diabetic who was referred to our centre for the management of a suppurating ulcer and swelling of the left hand of two weeks duration. On examination and work-up, the patient was found to have Lawal Group III left diabetic hand syndrome and was managed with parenteral antibiotics, radical debridement and the hand was eventually amputated. She died 7 days following amputation from overwhelming sepsis. Though tropical diabetic hand syndrome is a relatively rare complication of diabetes, it can be fatal as in this case report. Early diagnosis and proper management would yield better outcome. Initial management should include aggressive intravenous broad-spectrum antibiotics with anaerobic coverage. Classification of tropical diabetic hand syndrome will assist physicians and surgeons in decision making, proper management and easy communication.

Tropical and Holarctic Ants in Late Eocene Ambers

Directory of Open Access Journals (Sweden)

Perkovsky E. E.

2016-04-01

Full Text Available Based on representative collections, the ratio of tropical and Holarctic ant species in Priabonian (Late Eocene Baltic, Bitterfeld (Saxonian, Danish and Rovno ambers is analyzed for the first time. In surveyed representative collections of Baltic amber, the ratios of Holarctic and tropical ant species are from 1.1 to 1.5; with 10 Holarctic and 9 tropical species (out of 31 in the PIN-964 collection, and 9 and 5 species (out of 29 in the Giecewicz collection; the ratio in the representative collection of Saxonian amber is 0.9, 11 Holarctic species vs. 12 tropical species (out of 55; in the representative collection of Rovno amber it is 0.65, 15 vs. 23 species (out of 79; and in the representative collection of Danish amber it is 0.64, 7 vs. 11 species (out of 36. Hence, in representative collections of Baltic amber, Holarctic species clearly prevail not just in terms of the share of their specimens (by 9.8 to 19.6 times, but also by the number of species. In Bitterfeld amber, Holarctic species are somewhat less numerous than tropical ones, but their specimens are 6 times greater. In representative collections of Rovno and Danish ambers, the number of Holarctic species is 1.5 to 1.7 times smaller than that of tropical species, but the number of their specimens is 4.9 to 6.9 times greater. The numbers of tropical and Holarctic species represented by more than one specimen is similar in Priabonian ambers, 25 versus 22, but Holarctic species include four dominants or subdominants. The abundance of temperate elements in the Priabonian amber ant fauna along with the relatively small number of tropical elements greatly distinguishes it from the Middle European Lutetian ant faunas of Messel and Eckfeld in shale, which do not have temperate elements at all. Formica phaethusa Wheeler, Glaphyromyrmex oligocenicus Wheeler, Plagiolepis squamifera Mayr, Proceratium eocenicum Dlussky, Hypoponera atavia (Mayr, Ponera lobulifera Dlussky, Aphaenogaster mersa

Simulations of tropical rainforest albedo: is canopy wetness important?

Directory of Open Access Journals (Sweden)

Silvia N.M. Yanagi

Full Text Available Accurate information on surface albedo is essential for climate modelling, especially for regions such as Amazonia, where the response of the regional atmospheric circulation to the changes on surface albedo is strong. Previous studies have indicated that models are still unable to correctly reproduce details of the seasonal variation of surface albedo. Therefore, it was investigated the role of canopy wetness on the simulated albedo of a tropical rainforest by modifying the IBIS canopy radiation transfer code to incorporate the effects of canopy wetness on the vegetation reflectance. In this study, simulations were run using three versions of the land surface/ecosystem model IBIS: the standard version, the same version recalibrated to fit the data of albedo on tropical rainforests and a modified version that incorporates the effects of canopy wetness on surface albedo, for three sites in the Amazon forest at hourly and monthly scales. The results demonstrated that, at the hourly time scale, the incorporation of canopy wetness on the calculations of radiative transfer substantially improves the simulations results, whereas at the monthly scale these changes do not substantially modify the simulated albedo.

Dendrochronology in the dry tropics: the Ethiopian case

NARCIS (Netherlands)

Wils, T.; Sass-Klaassen, U.; Eshetu, Z.; Bräuning, A.; Gebrenirstos, A.; Couralet, C.; Robertson, I.; Touchan, R.; Koprowski, M.; Conway, D.; Briffa, K.R.; Beeckman, H.

2011-01-01

Dendrochronology is developing outside temperate and boreal regions. Over the past decade substantial progress has been made in Mediterranean and wet tropical regions. However, research in dry tropical regions, notably those of sub-Saharan Africa, has remained fragmentary. Here, we try to identify

A warming tropical central Pacific dries the lower stratosphere

Science.gov (United States)

Ding, Qinghua; Fu, Qiang

2018-04-01

The amount of water vapor in the tropical lower stratosphere (TLS), which has an important influence on the radiative energy budget of the climate system, is modulated by the temperature variability of the tropical tropopause layer (TTL). The TTL temperature variability is caused by a complex combination of the stratospheric quasi-biennial oscillation (QBO), tropospheric convective processes in the tropics, and the Brewer-Dobson circulation (BDC) driven by mid-latitude and subtropical atmospheric waves. In 2000, the TLS water vapor amount exhibited a stepwise transition to a dry phase, apparently caused by a change in the BDC. In this study, we present observational and modeling evidence that the epochal change of water vapor between the periods of 1992-2000 and 2001-2005 was also partly caused by a concurrent sea surface temperature (SST) warming in the tropical central Pacific. This SST warming cools the TTL above by enhancing the equatorial wave-induced upward motion near the tropopause, which consequently reduces the amount of water vapor entering the stratosphere. The QBO affects the TLS water vapor primarily on inter-annual timescales, whereas a classical El Niño southern oscillation (ENSO) event has small effect on tropical mean TLS water vapor because its responses are longitudinally out of phase. This study suggests that the tropical central Pacific SST is another driver of TLS water vapor variability on inter-decadal timescales and the tropical SST changes could contribute to about 30% of the step-wise drop of the lower stratospheric water vapor from 1992-2000 to 2001-2005.

Tropical Diabetic Hand Syndrome

African Journals Online (AJOL)

2015 Annals of Medical and Health Sciences Research | Published by Wolters Kluwer - Medknow. 473. Introduction ... diabetes.[2,3] Tropical diabetic hand syndrome is a terminology .... the importance of seeking medical attention immediately.

GARP Atlantic Tropical Experiment

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The GARP Atlantic Tropical Experiment (GATE) was the first major international experiment of the Global Atmospheric Research Program (GARP). It was conducted over...

Radio Occultation Bending Angle Anomalies During Tropical Cyclones

DEFF Research Database (Denmark)

Biondi, Riccardo; Neubert, Torsten; Syndergaard, Stig

signature in radio occultation profiles in the tropical tropopause layer. Using tropical cyclone best track database and data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC), we show that the bending angle anomaly of a GPS radio occultation signal is typically larger...

Strategies for global monitoring of tropical forests

Science.gov (United States)

Raymond L. Czaplewski

1994-01-01

The Food and Agricultural Organization (FAO) of the United Nations is conducting a global assessment of tropical forest resources, which will be accomplished by mid-1992. This assessment requires, in part, estimates of the total area of tropical forest cover in 1990 and the rate of change in forest cover between 1980 and 1990. The following are described here: (1) the...

Sawtooth forces in cutting tropical hardwoods native to South America

Science.gov (United States)

S. P. Loehnertz; I. V. Cooz

As a result of design, operation, and maintenance, sawblades used in tropical sawmills can cause many problems. Improvements in these areas are needed to reduce the waste associated with sawing of tropical species that are regarded as difficult to cut. In this study, cutting experiments that simulated bandsawing of tropical hardwoods showed the effect of chip...

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

Trends in size of tropical deforestation events signal increasing dominance of industrial-scale drivers

Science.gov (United States)

Austin, Kemen G.; González-Roglich, Mariano; Schaffer-Smith, Danica; Schwantes, Amanda M.; Swenson, Jennifer J.

2017-05-01

Deforestation continues across the tropics at alarming rates, with repercussions for ecosystem processes, carbon storage and long term sustainability. Taking advantage of recent fine-scale measurement of deforestation, this analysis aims to improve our understanding of the scale of deforestation drivers in the tropics. We examined trends in forest clearings of different sizes from 2000-2012 by country, region and development level. As tropical deforestation increased from approximately 6900 kha yr-1 in the first half of the study period, to >7900 kha yr-1 in the second half of the study period, >50% of this increase was attributable to the proliferation of medium and large clearings (>10 ha). This trend was most pronounced in Southeast Asia and in South America. Outside of Brazil >60% of the observed increase in deforestation in South America was due to an upsurge in medium- and large-scale clearings; Brazil had a divergent trend of decreasing deforestation, >90% of which was attributable to a reduction in medium and large clearings. The emerging prominence of large-scale drivers of forest loss in many regions and countries suggests the growing need for policy interventions which target industrial-scale agricultural commodity producers. The experience in Brazil suggests that there are promising policy solutions to mitigate large-scale deforestation, but that these policy initiatives do not adequately address small-scale drivers. By providing up-to-date and spatially explicit information on the scale of deforestation, and the trends in these patterns over time, this study contributes valuable information for monitoring, and designing effective interventions to address deforestation.

Tropical Cyclone Intensity Estimation Using Deep Convolutional Neural Networks

Science.gov (United States)

Maskey, Manil; Cecil, Dan; Ramachandran, Rahul; Miller, Jeffrey J.

2018-01-01

Estimating tropical cyclone intensity by just using satellite image is a challenging problem. With successful application of the Dvorak technique for more than 30 years along with some modifications and improvements, it is still used worldwide for tropical cyclone intensity estimation. A number of semi-automated techniques have been derived using the original Dvorak technique. However, these techniques suffer from subjective bias as evident from the most recent estimations on October 10, 2017 at 1500 UTC for Tropical Storm Ophelia: The Dvorak intensity estimates ranged from T2.3/33 kt (Tropical Cyclone Number 2.3/33 knots) from UW-CIMSS (University of Wisconsin-Madison - Cooperative Institute for Meteorological Satellite Studies) to T3.0/45 kt from TAFB (the National Hurricane Center's Tropical Analysis and Forecast Branch) to T4.0/65 kt from SAB (NOAA/NESDIS Satellite Analysis Branch). In this particular case, two human experts at TAFB and SAB differed by 20 knots in their Dvorak analyses, and the automated version at the University of Wisconsin was 12 knots lower than either of them. The National Hurricane Center (NHC) estimates about 10-20 percent uncertainty in its post analysis when only satellite based estimates are available. The success of the Dvorak technique proves that spatial patterns in infrared (IR) imagery strongly relate to tropical cyclone intensity. This study aims to utilize deep learning, the current state of the art in pattern recognition and image recognition, to address the need for an automated and objective tropical cyclone intensity estimation. Deep learning is a multi-layer neural network consisting of several layers of simple computational units. It learns discriminative features without relying on a human expert to identify which features are important. Our study mainly focuses on convolutional neural network (CNN), a deep learning algorithm, to develop an objective tropical cyclone intensity estimation. CNN is a supervised learning

Tropical influence on boreal summer mid-latitude stationary waves

Energy Technology Data Exchange (ETDEWEB)

Douville, Herve [Meteo-France/CNRM-GAME, Toulouse (France); CNRM/GMGEC/VDR, Toulouse (France); Bielli, S.; Deque, M.; Tyteca, S.; Voldoire, A. [Meteo-France/CNRM-GAME, Toulouse (France); Cassou, C. [CNRS-Cerfacs, Toulouse (France); Hall, N.M.J. [CNES/LEGOS, Toulouse (France)

2011-11-15

While organized tropical convection is a well-known source of extratropical planetary waves, state-of-the-art climate models still show serious deficiencies in simulating accurately the atmospheric response to tropical sea surface temperature (SST) anomalies and the associated teleconnections. In the present study, the remote influence of the tropical atmospheric circulation is evaluated in ensembles of global boreal summer simulations in which the Arpege-Climat atmospheric General Circulation Model (GCM) is nudged towards 6-h reanalyses. The nudging is applied either in the whole tropical band or in a regional summer monsoon domain. Sensitivity tests to the experimental design are first conducted using prescribed climatological SST. They show that the tropical relaxation does not improve the zonal mean extratropical climatology but does lead to a significantly improved representation of the mid-latitude stationary waves in both hemispheres. Low-pass filtering of the relaxation fields has no major effect on the model response, suggesting that high-frequency tropical variability is not responsible for extratropical biases. Dividing the nudging strength by a factor 10 only decreases the magnitude of the response. Model errors in each monsoon domain contribute to deficiencies in the model's mid-latitude climatology, although an exaggerated large-scale subsidence in the central equatorial Pacific appears as the main source of errors for the representation of stationary waves in the Arpege-Climat model. Case studies are then conducted using either climatological or observed SST. The focus is first on summer 2003 characterized by a strong and persistent anticyclonic anomaly over western Europe. This pattern is more realistic in nudging experiments than in simulations only driven by observed SST, especially when the nudging domain is centred over Central America. Other case studies also show a significant tropical forcing of the summer mid-latitude stationary waves

Effects of food supplementation on a tropical bird.

Science.gov (United States)

Class, Alexandra M; Moore, Ignacio T

2013-10-01

Tropical birds typically exhibit a 'slow pace of life' relative to higher latitude species. This is often manifested as slow development, low fecundity, and high survival. Following from this, it is predicted that tropical birds may be more likely to trade current reproductive effort to favor self-maintenance, thus supporting survival and future reproduction. To test this idea, we conducted two food supplementation experiments on tropical rufous-collared sparrows (Zonotrichia capensis) in the eastern Andes of Ecuador. In the first experiment, we food-supplemented pairs during the non-breeding life-history stage, and in the second experiment, we food-supplemented pairs that were provisioning fledglings. In both experiments, a larger proportion of food-supplemented birds exhibited pre-basic molt (replacement of feathers) than in a control group. To our knowledge, this is the first study to experimentally demonstrate that a food-supplemented bird invests extra resources into molt, a form of self-maintenance, and contrasts with the majority of food supplementation studies in high latitude birds that show they typically advance the initiation of, or extend the period of, reproduction. Our results are consistent with the syndrome of the slow pace of life in the tropics and support the concept of fundamental differences between temperate-zone and tropical birds.

Seamless Modeling for Research & Predictability of Severe Tropical Storms from Weather-to-Climate Timescales

Science.gov (United States)

Ramaswamy, V.; Chen, J. H.; Delworth, T. L.; Knutson, T. R.; Lin, S. J.; Murakami, H.; Vecchi, G. A.

2017-12-01

Damages from catastrophic tropical storms such as the 2017 destructive hurricanes compel an acceleration of scientific advancements to understand the genesis, underlying mechanisms, frequency, track, intensity, and landfall of these storms. The advances are crucial to provide improved early information for planners and responders. We discuss the development and utilization of a global modeling capability based on a novel atmospheric dynamical core ("Finite-Volume Cubed Sphere or FV3") which captures the realism of the recent tropical storms and is a part of the NOAA Next-Generation Global Prediction System. This capability is also part of an emerging seamless modeling system at NOAA/ Geophysical Fluid Dynamics Laboratory for simulating the frequency of storms on seasonal and longer timescales with high fidelity e.g., Atlantic hurricane frequency over the past decades. In addition, the same modeling system has also been employed to evaluate the nature of projected storms on the multi-decadal scales under the influence of anthropogenic factors such as greenhouse gases and aerosols. The seamless modeling system thus facilitates research into and the predictability of severe tropical storms across diverse timescales of practical interest to several societal sectors.

Comparison of tropical and subtropical glacier surface energy balance in Africa and South America

Science.gov (United States)

Nicholson, L.; Prinz, R.; Kinnard, C.; Mölg, T.; Winkler, M.; Kaser, G.

2010-05-01

Tropical glaciers exist only at high altitude, and meteorological and surface energy balance studies of these glaciers can tell us much about the conditions and changes occurring in the mid troposphere. Understanding the surface energy balance and resultant mass balance regime of tropical glaciers is prerequisite to predicting glacier evolution, and future meltwater contributions to local hydrological resources, in response to future climate scenarios. Tropical glacier mass balance variability is strongly linked to precipitation and, via this, to multi-annual climate oscillations such as ENSO and IOZM, so it is useful to understand what role these differing regional influences play in comparison to the similarities imposed by the overarching tropical climate conditions and seasonality. New surface energy balance and mass balance data is available from Lewis glacier (Kenya, 0°09' S; 37°18' E), and here we use an energy and mass balance model to determine the surface energy flux characteristics at this site through a wet and dry season. Results are compared with those from Kersten glacier (Tanzania, 3°04' S; 37°21' E) to understand how conditions at these two glaciers compare and thus what coherent and contrasting climatic information glaciological records from these two sites can be expected to deliver. Meteorological data available from glacier stations on Antizana (Ecuador, 0°25' S; 78°09' W), Artesonraju (Peru, 8°28' S; 77°38' W) Zongo (Bolivia, 16°39' S; 67°47' W) and Guanaco (Chile, 29°20' S; 70°00' W) glaciers in South America offer the opportunity to examine how the surface fluxes and seasonal variability of the energy balance compares to those of the African glaciers. We include the extra-tropical Chilean example for comparison with the similarly high altitude, cold ice of Kersten glacier.

Tropical diseases of the myocardium: a review

Directory of Open Access Journals (Sweden)

Groom ZC

2017-04-01

Full Text Available Zoe C Groom,1 Aristotle D Protopapas,2 Vasileios Zochios3,4 1Costello Medical Consulting Limited, Cambridge, 2Department of Surgery, Division of Surgery and Cancer, Imperial College London, London, 3Department of Intensive Care Medicine, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, 4College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK Abstract: Cardiovascular diseases are widely distributed throughout the world. Human parasitic infections are ubiquitous. Tropical parasites are increasingly recognized as causes of cardiovascular diseases. In this review, we address the most frequently reported parasites that directly infect the myocardium, including Trypanosoma cruzi, the protozoal causative agent of American trypanosomiasis (Chagas disease, and Taenia solium, the cestode causative agent of taeniasis and cysticercosis. We also discuss tropical endomyocardial fibrosis, trichinellosis and schistosomiasis. Health systems, attitudes, the perceptions of both patients and physicians as well as socioeconomic factors should all be explored and recognized as crucial factors for improving the control of cardiovascular diseases in the tropics. Clinicians throughout the world must remain aware of imported parasites as potential causes of cardiac diseases. Keywords: cardiomyopathy, Chagas disease, myocardium, parasitic infection, tropical infections

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.

Glacier monitoring and glacier-climate interactions in the tropical Andes: A review

Science.gov (United States)

Veettil, Bijeesh Kozhikkodan; Wang, Shanshan; Florêncio de Souza, Sergio; Bremer, Ulisses Franz; Simões, Jefferson Cardia

2017-08-01

In this review, we summarized the evolution of glacier monitoring in the tropical Andes during the last few decades, particularly after the development of remote sensing and photogrammetry. Advantages and limitations of glacier mapping, applied so far, in Venezuela, Colombia, Ecuador, Peru and Bolivia are discussed in detail. Glacier parameters such as the equilibrium line altitude, snowline and mass balance were given special attention in understanding the complex cryosphere-climate interactions, particularly using remote sensing techniques. Glaciers in the inner and the outer tropics were considered separately based on the precipitation and temperature conditions within a new framework. The applicability of various methods to use glacier records to understand and reconstruct the tropical Andean climate between the Last Glacial Maximum (11,700 years ago) and the present is also explored in this paper. Results from various studies published recently were analyzed and we tried to understand the differences in the magnitudes of glacier responses towards the climatic perturbations in the inner tropics and the outer tropics. Inner tropical glaciers, particularly those in Venezuela and Colombia near the January Intertropical Convergence Zone (ITCZ), are more vulnerable to increase in temperature. Surface energy balance experiments show that outer tropical glaciers respond to precipitation variability very rapidly in comparison with the temperature variability, particularly when moving towards the subtropics. We also analyzed the gradients in glacier response to climate change from the Pacific coast towards the Amazon Basin as well as with the elevation. Based on the current trends synthesised from recent studies, it is hypothesized that the glaciers in the inner tropics and the southern wet outer tropics will disappear first as a response to global warming whereas glaciers in the northern wet outer tropics and dry outer tropics show resistance to warming trends due to

Contributions of Tropical Cyclones to the North Atlantic Climatological Rainfall as Observed from Satellites

Science.gov (United States)

Rodgers, Edward B.; Adler, Robert F.; Pierce, Harold F.; Einaudi, Franco (Technical Monitor)

2000-01-01

The tropical cyclone rainfall climatology study that was performed for the North Pacific was extended to the North Atlantic. Similar to the North Pacific tropical cyclone study, mean monthly rainfall within 444 km of the center of the North Atlantic tropical cyclones (i.e., that reached storm stage and greater) was estimated from passive microwave satellite observations during, an eleven year period. These satellite-observed rainfall estimates were used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the North Atlantic total rainfall during, June-November when tropical cyclones were most abundant. The main results from this study indicate: 1) that tropical cyclones contribute, respectively, 4%, 3%, and 4% to the western, eastern, and entire North Atlantic; 2) similar to that observed in the North Pacific, the maximum in North Atlantic tropical cyclone rainfall is approximately 5 - 10 deg poleward (depending on longitude) of the maximum non-tropical cyclone rainfall; 3) tropical cyclones contribute regionally a maximum of 30% of the total rainfall 'northeast of Puerto Rico, within a region near 15 deg N 55 deg W, and off the west coast of Africa; 4) there is no lag between the months with maximum tropical cyclone rainfall and non-tropical cyclone rainfall in the western North Atlantic, while in the eastern North Atlantic, maximum tropical cyclone rainfall precedes maximum non-tropical cyclone rainfall; 5) like the North Pacific, North Atlantic tropical cyclones Of hurricane intensity generate the greatest amount of rainfall in the higher latitudes; and 6) warm ENSO events inhibit tropical cyclone rainfall.

Malaria and Tropical Travel

Centers for Disease Control (CDC) Podcasts

Malaria is a serious mosquito-borne disease that can lead to death. This podcast discusses malaria risk when traveling to tropical areas, as well as how to protect yourself and your family from malaria infection.

The Genesis of Tropical Cyclone Bilis (2000) Associated with Cross-equatorial Surges

Institute of Scientific and Technical Information of China (English)

XU Yamei

2011-01-01

The purpose of this paper is to explore how a tropical cyclone forms from a pre-existing large-scale depression which has been observed and associated with cross-equatorial surges in the western North Pacific. Tropical cyclone Bilis (2000) was selected as the case to study. The research data used are from the results of the non-hydrostatic mesoscale model (MM5), which has successfully simulated the transformation of a pre-existing weak large-scale tropical depression into a strong tropical storm. The scale separation technique is used to separate the synoptic-scale and sub-synoptic-scale fields from the model output fields. The scale-separated fields show that the pre-existing synoptic-scale tropical depression and the subsynoptic scale tropical cyclone formed later were different scale systems from beginning to end. It is also shown that the pre-existing synoptic-scale tropical depression did not contract to become the tropical cyclone. A series of weak, sub-synoptic-scale low and high pressure systems appeared and disappeared in the synopticscale depression, with one of the low systems near the center of the synoptic-scale depression having deepened to become the tropical cyclone. The roles of the synoptic-scale flow and the sub-synoptic scale disturbances in the formation of the tropical cyclone are investigated by diagnoses of the scale-separated vertical vorticity equation. The results show that the early development of the sub-synoptic scale vortex was fundamentally dependent on the strengthening synoptic-scale environmental depression. The depression was strengthened by cross-equatorial surges, which increased the convergence of the synoptic-scale depression at low levels and triggered the formation of the tropical cyclone.

High hydrostatic pressure processing of tropical fruits.

Science.gov (United States)

Lopes, Maria Lúcia M; Valente Mesquita, Vera L; Chiaradia, Ana Cristina N; Fernandes, Antônio Alberto R; Fernandes, Patricia M B

2010-02-01

Interest in the nonthermal method of high hydrostatic pressure (HHP) for food preservation has increased recently due to the possibility of inactivating microorganisms and enzymes while maintaining product sensorial and nutritional properties. This work deals with HHP use for the preservation of tropical fruit products. HHP is shown to be a practical approach to obtaining high-quality tropical fruit products that are both nutritive and safe.

An Estimate Of The Number Of Tropical Tree Species.

OpenAIRE

Slik, J W Ferry; Arroyo-Rodríguez, Víctor; Aiba, Shin-Ichiro; Alvarez-Loayza, Patricia; Alves, Luciana F; Ashton, Peter; Balvanera, Patricia; Bastian, Meredith L; Bellingham, Peter J; van den Berg, Eduardo; Bernacci, Luis; da Conceição Bispo, Polyanna; Blanc, Lilian; Böhning-Gaese, Katrin; Boeckx, Pascal

2016-01-01

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher's alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between similar to 40,000 and similar to 53,000...

Ectomycorrhizal fungi in Amazonian tropical forests in Colombia

NARCIS (Netherlands)

Vasco Palacios, A.M.

2016-01-01

The ectomycorrhizal (EcM) symbiosis was assumed to be restricted to the temperate regions where forests are dominated by EcM host plants, and the tropics were supposed to be dominated by endomycorrhizal fungi. However, evidence of the presence of EcM symbiosis in tropical lowland ecosystems has been

Characterizing Tropical Forest Structure using Field-based Measurements and a Terrestrial Lidar

Science.gov (United States)

Palace, M. W.; Sullivan, F.; Ducey, M. J.; Herrick, C.

2015-12-01

Forest structure comprises numerous quantifiable components of forest biometric characteristics, one of which is tree architecture. This structural component is important in the understanding of the past and future trajectories of these biomes. Tropical forests are often considered the most structurally complex and yet least understood of forested ecosystems. New technologies have provided novel avenues for quantifying properties of forested ecosystems, one of which is LIght Detection And Ranging (lidar). This sensor can be deployed on satellite, aircraft, unmanned aerial vehicles, and terrestrial platforms. In this study we examined the efficacy of a terrestrial lidar scanner (TLS) system in a tropical forest to estimate forest structure. Our study was conducted in January 2012 at La Selva, Costa Rica at twenty locations in predominantly undisturbed forest. At these locations we collected field measured biometric attributes using a variable plot design. We also collected TLS data from the center of each plot. Using this data we developed relative vegetation profiles (RVPs) and calculated a series of parameters including entropy, FFT, number of layers and plant area index to develop statistical relationships with field data. We developed statistical models using multiple linear regressions, all of which converged on statistically significant relationships with the strongest relationship being for mean crown depth (r2 = 0.87, p information on tropical forest structure.

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

Natural and Anthropogenically Perturbed Biogenic Aerosol over Tropical South East Asia

Science.gov (United States)

Coe, H.; Robinson, N.; Allan, J. D.; Hewitt, C. N.

2014-12-01

Tropical forested regions are of interest as sources of atmospheric aerosol since they cover very large areas of the tropics and are a source of a large amount of volatile organic compounds which act as precursors for particle formation. Natural forest regions offer the potential to study the background state of the tropics and so potentially gain some insight into the pre-perturbed atmosphere. However, over the last decade in South East Asia, a considerable fraction of the native tropical deciduous forest has been deforested and replanted with palm oil plantations. This changes the range of volatile organic compounds that are emitted and act as sources of secondary organic aerosol. A suite of intensive ground and airborne measurements were made over both tropical forest and oil palm plantations in Sabah, Malaysia as part of the "Oxidant and Particle Photochemical Processes above a South East Asian tropical rainforest (OP3) during 2008. These data will be used together with recent improvements in our understanding of aerosol formation from biogenic compounds to discuss aerosol formation in tropical regions and the influence of human influence through widespread palm oil agriculture.

Are Mixed Tropical Tree Plantations More Resistant to Drought than Monocultures?

Directory of Open Access Journals (Sweden)

Norbert Kunert

2015-06-01

Full Text Available Tropical tree plantations usually consist of a single exotic fast growing species, but recent research describes positive effects on ecosystem functions from mixed tropical tree plantations. In this review, we present the current knowledge of drought resistance of tropical mixed species plantations and summarize preliminary evidence from a tree biodiversity experiment in Panama. Converting mono-specific stands into mixed ones may improve stand stability and might reduce increasing abiotic and biotic disturbances due to climate change. However, little is known about the extent to which tropical tree species or tropical tree communities can resist increasing disturbances in the short term, e.g., water limitations due to increasing dry season intensity or length, or about their resilience after such disturbances and their capacity to adapt to changing conditions in the long term. Studies relating drought resistance and resilience to community diversity are missing. Further, we highlight the urgent need for a multifactorial manipulative throughfall reduction experiment in tropical environments. The outcome of such studies would greatly assist the forestry sector in tropical regions to maintain highly productive and ecologically sound forest plantations in a changing climate.

ENSO signals on sea-surface salinity in the eastern tropical pacific ocean

Directory of Open Access Journals (Sweden)

1998-01-01

Full Text Available SIGNAUX DE L’ENSO SUR LA SALINITE DE LA SURFACE DE LA MER DANS L’OCEAN PACIFIQUE TROPICAL ORIENTAL. Nous présentons les variations de la température et de la salinité de surface. Des navires de commerce ont été récemment équipés de thermosalinographes automatiques qui permettent d’échantillonner en continu et de localiser le front de salinité le long de la ligne Panama-Tahiti, séparant les masses d’eaux du golfe de Panama et celles du Pacifique central sud. La variation en latitude de la position du front halin suit la position de la zone de convergence intertropicale des vents du Pacifique. La salinité donne ainsi des informations supplémentaires sur le développement du phénomène El Niño dans le Pacifique tropical. La future transmission par satellite de la salinité de surface permettra de suivre en temps réel la distribution de la salinité de surface qui est étroitement liée aux échanges entre l’océan et l’atmosphère. SEÑALES DEL ENSO SOBRE LA SALINIDAD DE LA SUPERFICIE DEL OCÉANO PACÍFICO ORIENTAL. Presentamos las variaciones de la temperatura y de la salinidad de superficie. Barcos de comercio fueron recientemente equipados con termo-saliógrafos automáticos, los cuales permiten observar un muestreo continuo y ubicar el frente de salinidad en la recta Panamá-Tahiti, la cual separa las masas de agua del golfo de Panamá con las del Pacífico centro Sur. La variación en latitud de la ubicación del frente halino acompaña a la posición de la Zona de Convergencia Intertropical de los vientos del Pacífico. La salinidad proporciona también informaciones adicionales sobre el desarrollo del Fenómeno El Niño en el Pacífico tropical. La futura transmisión por satélite de la salinidad de superficie permitirá el monitoreo en tiempo real de la distribución en tiempo real de la salinidad de superficie, la cual está estrechamente vinculada con los intercambios entre el océano y la atmósfera. Various data

Biochar boosts tropical but not temperate crop yields

Science.gov (United States)

Jeffery, Simon; Abalos, Diego; Prodana, Marija; Catarina Bastos, Ana; van Groenigen, Jan Willem; Hungate, Bruce A.; Verheijen, Frank

2017-05-01

Applying biochar to soil is thought to have multiple benefits, from helping mitigate climate change [1, 2], to managing waste [3] to conserving soil [4]. Biochar is also widely assumed to boost crop yield [5, 6], but there is controversy regarding the extent and cause of any yield benefit [7]. Here we use a global-scale meta-analysis to show that biochar has, on average, no effect on crop yield in temperate latitudes, yet elicits a 25% average increase in yield in the tropics. In the tropics, biochar increased yield through liming and fertilization, consistent with the low soil pH, low fertility, and low fertilizer inputs typical of arable tropical soils. We also found that, in tropical soils, high-nutrient biochar inputs stimulated yield substantially more than low-nutrient biochar, further supporting the role of nutrient fertilization in the observed yield stimulation. In contrast, arable soils in temperate regions are moderate in pH, higher in fertility, and generally receive higher fertilizer inputs, leaving little room for additional benefits from biochar. Our findings demonstrate that the yield-stimulating effects of biochar are not universal, but may especially benefit agriculture in low-nutrient, acidic soils in the tropics. Biochar management in temperate zones should focus on potential non-yield benefits such as lime and fertilizer cost savings, greenhouse gas emissions control, and other ecosystem services.

Infectious Diseases and Tropical Cyclones in Southeast China

Directory of Open Access Journals (Sweden)

Jietao Zheng

2017-05-01

Full Text Available Southeast China is frequently hit by tropical cyclones (TCs with significant economic and health burdens each year. However, there is a lack of understanding of what infectious diseases could be affected by tropical cyclones. This study aimed to examine the impacts of tropical cyclones on notifiable infectious diseases in southeast China. Disease data between 2005 and 2011 from four coastal provinces in southeast China, including Guangdong, Hainan, Zhejiang, and Fujian province, were collected. Numbers of cases of 14 infectious diseases were compared between risk periods and reference periods for each tropical cyclone. Risk ratios (RRs were calculated to estimate the risks. TCs were more likely to increase the risk of bacillary dysentery, paratyphoid fever, dengue fever and acute hemorrhagic conjunctivitis (ps < 0.05 than to decrease the risk, more likely to decrease the risk of measles, mumps, varicella and vivax malaria (ps < 0.05 than to increase the risk. In conclusion, TCs have mixed effects on the risk of infectious diseases. TCs are more likely to increase the risk of intestinal and contact transmitted infectious diseases than to decrease the risk, and more likely to decrease the risk of respiratory infectious diseases than to increase the risk. Findings of this study would assist in developing public health strategies and interventions for the reduction of the adverse health impacts from tropical cyclones.

Modelling tropical forests response to logging

Science.gov (United States)

Cazzolla Gatti, Roberto; Di Paola, Arianna; Valentini, Riccardo; Paparella, Francesco

2013-04-01

Tropical rainforests are among the most threatened ecosystems by large-scale fragmentation due to human activity such as heavy logging and agricultural clearance. Although, they provide crucial ecosystem goods and services, such as sequestering carbon from the atmosphere, protecting watersheds and conserving biodiversity. In several countries forest resource extraction has experienced a shift from clearcutting to selective logging to maintain a significant forest cover and understock of living biomass. However the knowledge on the short and long-term effects of removing selected species in tropical rainforest are scarce and need to be further investigated. One of the main effects of selective logging on forest dynamics seems to be the local disturbance which involve the invasion of open space by weed, vines and climbers at the expense of the late-successional state cenosis. We present a simple deterministic model that describes the dynamics of tropical rainforest subject to selective logging to understand how and why weeds displace native species. We argue that the selective removal of tallest tropical trees carries out gaps of light that allow weeds, vines and climbers to prevail on native species, inhibiting the possibility of recovery of the original vegetation. Our results show that different regime shifts may occur depending on the type of forest management adopted. This hypothesis is supported by a dataset of trees height and weed/vines cover that we collected from 9 plots located in Central and West Africa both in untouched and managed areas.

Potential of airborne radar to support the assessment of land cover in a tropical rain forest environment

NARCIS (Netherlands)

Sanden, van der J.J.; Hoekman, D.H.

1999-01-01

The potential of airborne radar systems as tools for collecting information in support of the assessment of tropical primary forests and derived cover types was examined. SAR systems operating with high spatial resolutions and different wavelengths (i.e., X-, C-, L- and P-band) acquired data in

A Look Under the Hood: How the JPL Tropical Cyclone Information System Uses Database Technologies to Present Big Data to Users

Science.gov (United States)

Knosp, B.; Gangl, M.; Hristova-Veleva, S. M.; Kim, R. M.; Li, P.; Turk, J.; Vu, Q. A.

2015-12-01

The JPL Tropical Cyclone Information System (TCIS) brings together satellite, aircraft, and model forecast data from several NASA, NOAA, and other data centers to assist researchers in comparing and analyzing data and model forecast related to tropical cyclones. The TCIS has been running a near-real time (NRT) data portal during North Atlantic hurricane season that typically runs from June through October each year, since 2010. Data collected by the TCIS varies by type, format, contents, and frequency and is served to the user in two ways: (1) as image overlays on a virtual globe and (2) as derived output from a suite of analysis tools. In order to support these two functions, the data must be collected and then made searchable by criteria such as date, mission, product, pressure level, and geospatial region. Creating a database architecture that is flexible enough to manage, intelligently interrogate, and ultimately present this disparate data to the user in a meaningful way has been the primary challenge. The database solution for the TCIS has been to use a hybrid MySQL + Solr implementation. After testing other relational database and NoSQL solutions, such as PostgreSQL and MongoDB respectively, this solution has given the TCIS the best offerings in terms of query speed and result reliability. This database solution also supports the challenging (and memory overwhelming) geospatial queries that are necessary to support analysis tools requested by users. Though hardly new technologies on their own, our implementation of MySQL + Solr had to be customized and tuned to be able to accurately store, index, and search the TCIS data holdings. In this presentation, we will discuss how we arrived on our MySQL + Solr database architecture, why it offers us the most consistent fast and reliable results, and how it supports our front end so that we can offer users a look into our "big data" holdings.

Biometrical applications in tropical pasture and agro-pastoral research

NARCIS (Netherlands)

Amézquita, M.C.

2001-01-01

"Biometrical Applications in Tropical Pasture and Agro-pastoral Research" illustrates, through selected Case Studies, the contribution of Biometry to pasture and agro-pastoral research in Tropical Latin America ( TLA ) in the last

Interaction between Tropical Atlantic Variability and El Niño-Southern Oscillation.

Science.gov (United States)

Saravanan, R.; Chang, Ping

2000-07-01

The interaction between tropical Atlantic variability and El Niño-Southern Oscillation (ENSO) is investigated using three ensembles of atmospheric general circulation model integrations. The integrations are forced by specifying observed sea surface temperature (SST) variability over a forcing domain. The forcing domain is the global ocean for the first ensemble, limited to the tropical ocean for the second ensemble, and further limited to the tropical Atlantic region for the third ensemble. The ensemble integrations show that extratropical SST anomalies have little impact on tropical variability, but the effect of ENSO is pervasive in the Tropics. Consistent with previous studies, the most significant influence of ENSO is found during the boreal spring season and is associated with an anomalous Walker circulation. Two important aspects of ENSO's influence on tropical Atlantic variability are noted. First, the ENSO signal contributes significantly to the `dipole' correlation structure between tropical Atlantic SST and rainfall in the Nordeste Brazil region. In the absence of the ENSO signal, the correlations are dominated by SST variability in the southern tropical Atlantic, resulting in less of a dipole structure. Second, the remote influence of ENSO also contributes to positive correlations between SST anomalies and downward surface heat flux in the tropical Atlantic during the boreal spring season. However, even when ENSO forcing is absent, the model integrations provide evidence for a positive surface heat flux feedback in the deep Tropics, which is analyzed in a companion study by Chang et al. The analysis of model simulations shows that interannual atmospheric variability in the tropical Pacific-Atlantic system is dominated by the interaction between two distinct sources of tropical heating: (i) an equatorial heat source in the eastern Pacific associated with ENSO and (ii) an off-equatorial heat source associated with SST anomalies near the Caribbean

[A case of relapsing iridocyclitis in tropical malaria].

Science.gov (United States)

Kravchinina, V V; Dushin, N V; Beliaev, V S; Barashkov, V I; Gonchar, P A; Frolov, M A

1997-01-01

An African student developed bilateral relapsing iridocyclitis with increased intraocular pressure. General examinations and parasitological studies revealed tropical malaria. Etiotropic and local therapy normalized intraocular pressure and improved vision acuity of both eyes. This case should be borne in mind by general practitioners as a possibility of transportation of various tropical diseases.

Averting biodiversity collapse in tropical forest protected areas

Science.gov (United States)

W.F. Laurance; D.C. Useche; J. Rendeiro; and others NO-VALUE; Ariel Lugo

2012-01-01

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon1–3. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment...

Global analysis of threat status reveals higher extinction risk in tropical than in temperate bird sister species

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Reif Jiří

2016-06-01

Full Text Available Given increasing pressures upon biodiversity, identification of species’ traits related to elevated extinction risk is useful for more efficient allocation of limited resources for nature conservation. Despite its need, such a global analysis was lacking in the case of birds. Therefore, we performed this exercise for avian sister species using information about their global extinction risk from IUCN Red List. We focused on 113 pairs of sister species, each containing a threatened and an unthreatened species to factor out the effects of common evolutionary history on the revealed relationship. We collected data on five traits with expected relationships to species’ extinction risk based on previous studies performed at regional or national levels: breeding habitat (recognizing forest, grassland, wetland and oceanic species, latitudinal range position (temperate and tropics species, migration strategy (migratory and resident species, diet (carnivorous, insectivorous, herbivorous and omnivorous species and body mass. We related the extinction risk using IUCN threat level categories to species’ traits using generalised linear mixed effects models expecting lower risk for forest, temperate, omnivorous and smaller-bodied species. Our expectation was confirmed only in the case of latitudinal range position, as we revealed higher threat level for tropical than for temperate species. This relationship was robust to different methods of threat level expression and cannot be explained by a simple association of high bird species richness with the tropical zone. Instead, it seems that tropical species are more threatened because of their intrinsic characteristics such as slow life histories, adaptations to stable environments and small geographic ranges. These characteristics are obviously disadvantageous in conditions of current human-induced environmental perturbations. Moreover, given the absence of habitat effects, our study indicates that such

AVHRR for monitoring global tropical deforestation

Science.gov (United States)

Malingreau, J. P.; Laporte, N.; Tucker, C. J.

1989-01-01

Advanced Very High Resolution Radiometer (AVHRR) data have been used to assess the dynamics of forest trnsformations in three parts of the tropical belt. A large portion of the Amazon Basin has been systematically covered by Local Area Coverage (LAC) data in the 1985-1987 period. The analysis of the vegetation index and thermal data led to the identification and measurement of large areas of active deforestation. The Kalimantan/Borneo forest fires were monitored and their impact was evaluated using the Global Area Coverage (GAC) 4 km resolution data. Finally, High Resolution Picture Transmission (HRPT) data have provided preliminary information on current activities taking place at the boundary between the savanna and the forest in the Southern part of West Africa. The AVHRR approach is found to be a highly valuable means for carrying out deforestation assessments in regional and global perspectives.

Cyberdiversity: improving the informatic value of diverse tropical arthropod inventories.

Directory of Open Access Journals (Sweden)

Jeremy A Miller

Full Text Available In an era of biodiversity crisis, arthropods have great potential to inform conservation assessment and test hypotheses about community assembly. This is because their relatively narrow geographic distributions and high diversity offer high-resolution data on landscape-scale patterns of biodiversity. However, a major impediment to the more widespread application of arthropod data to a range of scientific and policy questions is the poor state of modern arthropod taxonomy, especially in the tropics. Inventories of spiders and other megadiverse arthropods from tropical forests are dominated by undescribed species. Such studies typically organize their data using morphospecies codes, which make it difficult for data from independent inventories to be compared and combined. To combat this shortcoming, we offer cyberdiversity, an online community-based approach for reconciling results of independent inventory studies where current taxonomic knowledge is incomplete. Participating scientists can upload images and DNA barcode sequences to dedicated databases and submit occurrence data and links to a web site (www.digitalSpiders.org. Taxonomic determinations can be shared with a crowdsourcing comments feature, and researchers can discover specimens of interest available for loan and request aliquots of genomic DNA extract. To demonstrate the value of the cyberdiversity framework, we reconcile data from three rapid structured inventories of spiders conducted in Vietnam with an independent inventory (Doi Inthanon, Thailand using online image libraries. Species richness and inventory completeness were assessed using non-parametric estimators. Community similarity was evaluated using a novel index based on the Jaccard replacing observed with estimated values to correct for unobserved species. We use a distance-decay framework to demonstrate a rudimentary model of landscape-scale changes in community composition that will become increasingly informative as

Impacts of tropical cyclones on Fiji and Samoa

Science.gov (United States)

Kuleshov, Yuriy; Prakash, Bipendra; Atalifo, Terry; Waqaicelua, Alipate; Seuseu, Sunny; Ausetalia Titimaea, Mulipola

2013-04-01

Weather and climate hazards have significant impacts on Pacific Island Countries. Costs of hazards such as tropical cyclones can be astronomical making enormous negative economic impacts on developing countries. We highlight examples of extreme weather events which have occurred in Fiji and Samoa in the last few decades and have caused major economic and social disruption in the countries. Destructive winds and torrential rain associated with tropical cyclones can bring the most damaging weather conditions to the region causing economic and social hardship, affecting agricultural productivity, infrastructure and economic development which can persist for many years after the initial impact. Analysing historical data, we describe the impacts of tropical cyclones Bebe and Kina on Fiji. Cyclone Bebe (October 1972) affected the whole Fiji especially the Yasawa Islands, Viti Levu and Kadavu where hurricane force winds have been recorded. Nineteen deaths were reported and damage costs caused by cyclone Bebe were estimated as exceeding F20 million (F 1972). Tropical cyclone Kina passed between Fiji's two main islands of Viti Levu and Vanua Levu, and directly over Levuka on the night of 2 January 1993 with hurricane force winds causing extensive damage. Twenty three deaths have been reported making Kina one of the deadliest hurricanes in Fiji's recent history. Severe flooding on Viti Levu, combined with high tide and heavy seas led to destruction of the Sigatoka and Ba bridges, as well as almost complete loss of crops in Sigatoka and Navua deltas. Overall, damage caused by cyclone Kina was estimated as F170 million. In Samoa, we describe devastation to the country caused by tropical cyclones Ofa (February 1990) and Val (December 1991) which were considered to be the worst cyclones to affect the Samoan islands since the 1889 Apia cyclone. In Samoa, seven people were killed due to cyclone Ofa, thousands of people were left homeless and entire villages were destroyed. Damage

Coexistence of Dunes and Humid Conditions at Titan's Tropics

Science.gov (United States)

Radebaugh, Jani; Lorenz, R. D.; Lunine, J. I.; Kirk, R. L.; Ori, G. G.; Farr, T. G.; Malaska, M.; Le Gall, A.; Liu, Z. Y. C.; Encrenaz, P. J.; Paillou, P.; Hayes, A.; Lopes, R. M. C.; Turtle, E. P.; Wall, S. D.; Stofan, E. R.; Wood, C. A.; Cassini RADAR Team

2012-10-01

At Titan's equatorial latitudes there are tens of thousands of dunes, a landform typical of desert environments where sand does not become anchored by vegetation or fluids. Model climate simulations predict generally dry conditions at the equator and humid conditions near the poles of Titan, where lakes of methane/ethane are found. However, moderate relative methane humidity was observed at the Huygens landing site, recent rainfall was seen by Cassini ISS near the Belet Sand Sea, and a putative transient lake in Shangri-La was observed by Cassini VIMS, all of which indicate abundant fluids may be present, at least periodically, at Titan's equatorial latitudes. Terrestrial observations and studies demonstrate dunes can exist and migrate in conditions of high humidity. Active dunes are found in humid climates, indicating the movement of sand is not always prohibited by the presence of fluids. Sand mobility is related to precipitation, evaporation and wind speed and direction. If dune surfaces become wetted by rainfall or rising subsurface fluids, they can become immobilized. However, winds can act to dry the uppermost layers, freeing sands for saltation and enabling dune migration in wet conditions. Active dunes are found in tropical NE Brazil and NE Australia, where there are alternating dry and wet periods, a condition possible for Titan's tropics. Rising and falling water levels lead to the alteration of dune forms, mainly from being anchored by vegetation, but also from cementation by carbonates or clays. Studies of Titan's dunes, which could undergo anchoring of organic sediments by hydrocarbon fluids, could inform the relative strength of vegetation vs. cementation at humid dune regions on Earth. Furthermore, a comprehensive survey of dune morphologies near regions deemed low by SARTopo and stereo, where liquids may collect in wet conditions, could reveal if bodies of liquid have recently existed at Titan's tropics.

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

Warm Water Pools of the Western Caribbean and Eastern Tropical Pacific: Their Influence on Intraseasonal Rainfall Regimes and Tropical Storm Activity in Mexico

Science.gov (United States)

Douglas, A. V.; Englehart, P. J.

2007-05-01

A dipole in tropical cyclone development between the Caribbean and the eastern tropical Pacific will be examined relative to its affect on southern Mexican rainfall. With the change over in the AMO and PDO in 1994 and 1998, respectively, tropical storm genesis has been increasing in the Caribbean while declining in the tropical east Pacific. This dipole in tropical cyclone development appears to be related to changes in the pre storm season heat content of the two ocean basins (data Scripps Institution of Oceanography). Preliminary work indicates that if the Caribbean is warmer than the Pacific by late May the dipole will be accentuated with a pronounced decrease in tropical storms in the east Pacific with an early and prolonged season in the Caribbean. In recent years there appears to have been an increase in the intensity and duration of midsummer drought (Canicula) in Mexico associated with changes in the PDO and AMO. These long term ocean oscillations appear to control the dipole in the strength of the Caribbean and East Pacific warm pools. Mid summer drought is a normal occurrence in much of Mexico and Central America, but the intensified droughts of the recent period have stressed the agricultural community of the region. Based on preliminary work, it appears that the recent increased frequency of midsummer drought can be linked to a shift in the warmest pool from the East Pacific to the Caribbean.

Tropical cyclones over NIO during La-Nina Modoki years

Digital Repository Service at National Institute of Oceanography (India)

Sumesh, K.G.; RameshKumar, M.R.

Tropical cyclones over NIO (North Indian Ocean) are highly influenced by the El-Nino and La-Nina activities over the Pacific Ocean Influences of air-sea interaction processes like El-Nino Modoki and La-Nina Modoki on tropical cyclones are less...

Bibliometry of the Revista de Biología Tropical / International Journal of Tropical Biology and Conservation: document types, languages, countries, institutions, citations and article lifespan.

Science.gov (United States)

Monge-Nájera, Julián; Ho, Yuh-Shan

2016-09-01

The Revista de Biología Tropical / International Journal of Tropical Biology and Conservation, founded in 1953, publishes feature articles about tropical nature and is considered one of the leading journals in Latin America. This article analyzes document type, language, countries, institutions, citations and for the first time article lifespan, from 1976 through 2014. We analyzed 3 978 documents from the Science Citation Index Expanded. Articles comprised 88 % of the total production and had 3.7 citations on average, lower than reviews. Spanish and English articles were nearly equal in numbers and citation for English articles was only slightly higher. Costa Rica, Mexico, and the USA are the countries with more articles, and the leading institutions were Universidad de Costa Rica, Universidad Nacional, Universidad Nacional Autónoma de Mexico and Universidad de Oriente (Venezuela). The citation lifespan of articles is long, around 37 years. It is not surprising that Costa Rica, Mexico, and Venezuela lead in productivity and cooperation, because they are mostly covered by tropical ecosystems and share a common culture and a tradition of scientific cooperation. The same applies to the leading institutions, which are among the largest Spanish language universities in the neotropical region. American output can be explained by the regional presence of the Smithsonian Tropical Research Institute and the Organization for Tropical Studies. Tropical research does not have the rapid change typical of medical research, and for this reason, the impact factor misses most of citations for the Revista, which are made after the two-year window used by the Web of Science. This issue is especially damaging for the Revista because most journals that deal with tropical biology are never checked when citations are counted for by the Science Citation Index.

Diameter distribution in a Brazilian tropical dry forest domain: predictions for the stand and species.

Science.gov (United States)

Lima, Robson B DE; Bufalino, Lina; Alves, Francisco T; Silva, José A A DA; Ferreira, Rinaldo L C

2017-01-01

Currently, there is a lack of studies on the correct utilization of continuous distributions for dry tropical forests. Therefore, this work aims to investigate the diameter structure of a brazilian tropical dry forest and to select suitable continuous distributions by means of statistic tools for the stand and the main species. Two subsets were randomly selected from 40 plots. Diameter at base height was obtained. The following functions were tested: log-normal; gamma; Weibull 2P and Burr. The best fits were selected by Akaike's information validation criterion. Overall, the diameter distribution of the dry tropical forest was better described by negative exponential curves and positive skewness. The forest studied showed diameter distributions with decreasing probability for larger trees. This behavior was observed for both the main species and the stand. The generalization of the function fitted for the main species show that the development of individual models is needed. The Burr function showed good flexibility to describe the diameter structure of the stand and the behavior of Mimosa ophthalmocentra and Bauhinia cheilantha species. For Poincianella bracteosa, Aspidosperma pyrifolium and Myracrodum urundeuva better fitting was obtained with the log-normal function.

Promoting the confluence of tropical cyclone research.

Science.gov (United States)

Marler, Thomas E

2015-01-01

Contributions of biologists to tropical cyclone research may improve by integrating concepts from other disciplines. Employing accumulated cyclone energy into protocols may foster greater integration of ecology and meteorology research. Considering experienced ecosystems as antifragile instead of just resilient may improve cross-referencing among ecological and social scientists. Quantifying ecosystem capital as distinct from ecosystem services may improve integration of tropical cyclone ecology research into the expansive global climate change research community.

Application of DNA barcodes in wildlife conservation in Tropical East Asia.

Science.gov (United States)

Wilson, John-James; Sing, Kong-Wah; Lee, Ping-Shin; Wee, Alison K S

2016-10-01

Over the past 50 years, Tropical East Asia has lost more biodiversity than any tropical region. Tropical East Asia is a megadiverse region with an acute taxonomic impediment. DNA barcodes are short standardized DNA sequences used for taxonomic purposes and have the potential to lessen the challenges of biodiversity inventory and assessments in regions where they are most needed. We reviewed DNA barcoding efforts in Tropical East Asia relative to other tropical regions. We suggest DNA barcodes (or metabarcodes from next-generation sequencers) may be especially useful for characterizing and connecting species-level biodiversity units in inventories encompassing taxa lacking formal description (particularly arthropods) and in large-scale, minimal-impact approaches to vertebrate monitoring and population assessments through secondary sources of DNA (invertebrate derived DNA and environmental DNA). We suggest interest and capacity for DNA barcoding are slowly growing in Tropical East Asia, particularly among the younger generation of researchers who can connect with the barcoding analogy and understand the need for new approaches to the conservation challenges being faced. © 2016 Society for Conservation Biology.

Cicadas impact bird communication in a noisy tropical rainforest

Science.gov (United States)

Hall, Robert; Ray, William; Beck, Angela; Zook, James

2015-01-01

Many animals communicate through acoustic signaling, and “acoustic space” may be viewed as a limited resource that organisms compete for. If acoustic signals overlap, the information in them is masked, so there should be selection toward strategies that reduce signal overlap. The extent to which animals are able to partition acoustic space in acoustically diverse habitats such as tropical forests is poorly known. Here, we demonstrate that a single cicada species plays a major role in the frequency and timing of acoustic communication in a neotropical wet forest bird community. Using an automated acoustic monitor, we found that cicadas vary the timing of their signals throughout the day and that the frequency range and timing of bird vocalizations closely track these signals. Birds significantly avoid temporal overlap with cicadas by reducing and often shutting down vocalizations at the onset of cicada signals that utilize the same frequency range. When birds do vocalize at the same time as cicadas, the vocalizations primarily occur at nonoverlapping frequencies with cicada signals. Our results greatly improve our understanding of the community dynamics of acoustic signaling and reveal how patterns in biotic noise shape the frequency and timing of bird vocalizations in tropical forests. PMID:26023277

Tropical cyclone disasters in the Gulf of Thailand

Directory of Open Access Journals (Sweden)

Suphat Vongvisessomjai

2009-07-01

Full Text Available The origin of tropical cyclones in the South China Sea is over a vast deep sea, southeast of the Philippines. The severetropical cyclones in summer with northerly tracks attack the Philippines, China, Korea and Japan, while the moderate ones inthe rainy season with northwesterly tracks pass Vietnam, Laos and northern Thailand. In October, November and December, the tropical cyclones are weakened and tracks shift to a lower latitude passing the Gulf of Thailand. Tropical cyclone disasters in the Gulf of Thailand due to strong winds causing storm surges and big waves or heavy rainfall over high mountains in causing floods and land slides result in moderate damages and casualties. Analyses are made of six decades of data of tropical cyclones from 1951-2006 having averaged numbers of 3 and 13 in Thailand and the South China Sea respectively. Detailed calculation of surges and wave heights of the 5 disastrous tropical cyclones in the Gulf of Thailand reveal that the Upper Gulf of Thailand with a limited fetch length of about 100 km in north/south direction and about 100 km width in the east/west direction, resulted in a limited maximum wave height of 2.3-2.5 m and maximum storm surge height of 1.2 m generated by Typhoon Vae (1952, while the east coast, with longer fetch lengthbut still limited by the existence of its shoreline, resulted in an increased maximum wave height of 4 m and maximum storm surge height of 0.6 m in the Upper Gulf of Thailand generated by Typhoon Linda (1997. These are the Probable Maximum Cyclones here.The southern shoreline, with unlimited fetch length on the east by tropical cyclones approaching from the South China Sea, generated maximum wave height of 6-11 m by Typhoon Gay (1989, resulting in more casualties and damages. Note that storm surges on the southern shorelines with steep slopes are small due to the short distance of shallow shorelines in receiving wind stresses for piling up sea levels. These disasters can be

Tropical explosive volcanic eruptions can trigger El Niño by cooling tropical Africa.

Science.gov (United States)

Khodri, Myriam; Izumo, Takeshi; Vialard, Jérôme; Janicot, Serge; Cassou, Christophe; Lengaigne, Matthieu; Mignot, Juliette; Gastineau, Guillaume; Guilyardi, Eric; Lebas, Nicolas; Robock, Alan; McPhaden, Michael J

2017-10-03

Stratospheric aerosols from large tropical explosive volcanic eruptions backscatter shortwave radiation and reduce the global mean surface temperature. Observations suggest that they also favour an El Niño within 2 years following the eruption. Modelling studies have, however, so far reached no consensus on either the sign or physical mechanism of El Niño response to volcanism. Here we show that an El Niño tends to peak during the year following large eruptions in simulations of the Fifth Coupled Model Intercomparison Project (CMIP5). Targeted climate model simulations further emphasize that Pinatubo-like eruptions tend to shorten La Niñas, lengthen El Niños and induce anomalous warming when occurring during neutral states. Volcanically induced cooling in tropical Africa weakens the West African monsoon, and the resulting atmospheric Kelvin wave drives equatorial westerly wind anomalies over the western Pacific. This wind anomaly is further amplified by air-sea interactions in the Pacific, favouring an El Niño-like response.El Niño tends to follow 2 years after volcanic eruptions, but the physical mechanism behind this phenomenon is unclear. Here the authors use model simulations to show that a Pinatubo-like eruption cools tropical Africa and drives westerly wind anomalies in the Pacific favouring an El Niño response.

Tropical cyclone statistics in the Northeastern Pacific

Energy Technology Data Exchange (ETDEWEB)

Romero-Vadillo, E. [Universidad Autonoma de Baja California Sur (UABCS), La Paz, Baja California Sur (Mexico); Zaytsev, O. [Centro Interdisciplinario de Ciencias Marinas, Instituto Politecnico Nacional, La Paz, Baja California Sur (Mexico)]. E-mail: ozaytsev@ipn.mx; Morales-Perez, R. [Instituto Mexicano de Tecnologia del Agua (IMTA), Jiutepec, Morelos (Mexico)

2007-04-15

The principal area of tropical cyclogenesis in the tropical eastern Pacific Ocean is offshore in the Gulf of Tehuantepec, between 8 and 15 degrees Celsius N, and most of these cyclones move towards the west and northwest during their initial phase. Historical analysis of tropical cyclone data in the Northeastern (NE) Pacific over the last 38 years (from 1966 to 2004) shows a mean of 16.3 tropical cyclones per year, consisting of 8.8 hurricanes 198 and 7.4 tropical storms. The analysis shows great geographical variability of cyclone tracks, and that there were a considerable number of hurricane strikes along the Mexican coast. About 50% of the tropical cyclones formed turned north to northeast. It was rare that any passed further north than 30 degrees Celsius N in latitude because of the cold California Current. Hurricane tracks that affected the NE Pacific may be separated into 5 groups. We compared the historical record of the sea surface temperature (SST), related with the El Nino events with a data set of tropical cyclones, including frequency, intensity, trajectory, and duration. Although the statistical dependence between the frequencies of tropical cyclones of the most abundant categories, 1 and 2, over this region and SST data was not convincing, the percentage of high intensity hurricanes and hurricanes with a long life-time (greater than 12 days) was more during El Nino years than in non-El Nino years. [Spanish] La principal region de la formacion de ciclones en el oceano Pacifico Este es el Golfo de Tehuantepec, entre los 8 y los 15 grados Celsius N. En su fase inicial los ciclones se mueven hacia el oeste y el noroeste. El analisis historico de los ciclones que se han generado durante los ultimos 38 anos (de 1966 a 2004) muestra un promedio de 16.2 ciclones por ano, consistentes en 8.8 huracanes y 7.4 tormentas tropicales. El analisis muestra una gran variabilidad geografica en la trayectoria de los ciclones, de los cuales un gran numero impacta las

O 'combate' às doenças tropicais na imprensa colonial alemã 'Combating' tropical diseases in the German colonial press

Directory of Open Access Journals (Sweden)

Sílvio Marcus de Souza Correa

2013-03-01

Full Text Available Demonstra o quanto determinados jornais em língua alemã constituíram veículo de divulgação para o público leigo sobre o 'combate' às doenças tropicais. Pela imprensa, imigrantes e seus descendentes no Brasil eram informados não apenas sobre as doenças que acometiam os colonos alemães na África, mas também sobre medidas de saneamento, profilaxia, experimentos da medicina tropical etc. A partir de fontes hemerográficas, demonstra o quanto as comunidades alemãs no ultramar lograram compartilhar suas experiências em relação à saúde em regiões tropicais e/ou subtropicais.This article shows how much certain German language newspapers were a vehicule for reporting to the lay public on 'combating' tropical diseases. Through the press, immigrants and their descendents in Brazil were informed not only about the diseases which afflicted German colonists in Africa, but also about measures concerning sanitation, prophylaxis and experiments with tropical medicine, etc. Based on hemerographic sources, it shows how successful the overseas German communities were in sharing their experiences regarding health in tropical and/or sub-tropical regions.

Infrared heater system for warming tropical forest understory plants and soils

Science.gov (United States)

Bruce A. Kimball; Aura M. Alonso-Rodríguez; Molly A. Cavaleri; Sasha C. Reed; Grizelle González; Tana E. Wood

2018-01-01

The response of tropical forests to global warming is one of the largest uncertainties in predicting the future carbon balance of Earth. To determine the likely effects of elevated temperatures on tropical forest understory plants and soils, as well as other ecosystems, an infrared (IR) heater system was developed to provide in situ warming for the Tropical Responses...

Tropical rainforest response to marine sky brightening climate engineering

Science.gov (United States)

Muri, Helene; Niemeier, Ulrike; Kristjánsson, Jón Egill

2015-04-01

Tropical forests represent a major atmospheric carbon dioxide sink. Here the gross primary productivity (GPP) response of tropical rainforests to climate engineering via marine sky brightening under a future scenario is investigated in three Earth system models. The model response is diverse, and in two of the three models, the tropical GPP shows a decrease from the marine sky brightening climate engineering. Partial correlation analysis indicates precipitation to be important in one of those models, while precipitation and temperature are limiting factors in the other. One model experiences a reversal of its Amazon dieback under marine sky brightening. There, the strongest partial correlation of GPP is to temperature and incoming solar radiation at the surface. Carbon fertilization provides a higher future tropical rainforest GPP overall, both with and without climate engineering. Salt damage to plants and soils could be an important aspect of marine sky brightening.

Gigantic Jets and the Tropical Paradigm: A Satellite Perspective

Science.gov (United States)

Lazarus, S. M.; Splitt, M. E.

2017-12-01

While not exclusively oceanic, gigantic jets (GJ) appear to have a preference for the tropical environment. In particular, a number of GJs have been observed in conjunction with tropical disturbances (i.e., weak tropical storms, depressions, and remnant lows). Given the remote aspect of TC convection and general lack of radar coverage, we explore this subset of events via analysis of their infrared and water vapor satellite presentations. The satellite perspective is relevant given that storm top mixing (dilution) of charge associated with storm-scale turbulence in this portion of the storm is thought to be connected to GJs. The thunderstorm overshoot, upper level divergence / outflow are examined in an effort to better understand the tropical paradigm. Specifically, an analysis of cloud top temperature, anvil expansion rates and asymmetries as well as placement of the GJ events with respect to the large (storm) scale circulation will be conducted.

Cloud Cover Assessment for Operational Crop Monitoring Systems in Tropical Areas

Directory of Open Access Journals (Sweden)

Isaque Daniel Rocha Eberhardt

2016-03-01

Full Text Available The potential of optical remote sensing data to identify, map and monitor croplands is well recognized. However, clouds strongly limit the usefulness of optical imagery for these applications. This paper aims at assessing cloud cover conditions over four states in the tropical and sub-tropical Center-South region of Brazil to guide the development of an appropriate agricultural monitoring system based on Landsat-like imagery. Cloudiness was assessed during overlapping four months periods to match the typical length of crop cycles in the study area. The percentage of clear sky occurrence was computed from the 1 km resolution MODIS Cloud Mask product (MOD35 considering 14 years of data between July 2000 and June 2014. Results showed high seasonality of cloud occurrence within the crop year with strong variations across the study area. The maximum seasonality was observed for the two states in the northern part of the study area (i.e., the ones closer to the Equator line, which also presented the lowest averaged values (15% of clear sky occurrence during the main (summer cropping period (November to February. In these locations, optical data faces severe constraints for mapping summer crops. On the other hand, relatively favorable conditions were found in the southern part of the study region. In the South, clear sky values of around 45% were found and no significant clear sky seasonality was observed. Results underpin the challenges to implement an operational crop monitoring system based solely on optical remote sensing imagery in tropical and sub-tropical regions, in particular if short-cycle crops have to be monitored during the cloudy summer months. To cope with cloudiness issues, we recommend the use of new systems with higher repetition rates such as Sentinel-2. For local studies, Unmanned Aircraft Vehicles (UAVs might be used to augment the observing capability. Multi-sensor approaches combining optical and microwave data can be another

Tropical limit and a micro-macro correspondence in statistical physics

Science.gov (United States)

Angelelli, Mario

2017-10-01

Tropical mathematics is used to establish a correspondence between certain microscopic and macroscopic objects in statistical models. Tropical algebra gives a common framework for macrosystems (subsets) and their elementary constituents (elements) that is well-behaved with respect to composition. This kind of connection is studied with maps that preserve a monoid structure. The approach highlights an underlying order relation that is explored through the concepts of filter and ideal. Particular attention is paid to asymmetry and duality between max- and min-criteria. Physical implementations are presented through simple examples in thermodynamics and non-equilibrium physics. The phenomenon of ultrametricity, the notion of tropical equilibrium and the role of ground energy in non-equilibrium models are discussed. Tropical symmetry, i.e. idempotence, is investigated.

The Scientific Development of the Physiology of Plants in the American Tropics

Directory of Open Access Journals (Sweden)

Marco V. Gutiérrez

2002-06-01

Full Text Available This paper is a research and journalistic work that summarizes and synthesizes the scientific development of the physiology of plants in the American tropics, also known as the Neotropics. It contains the contributions of numerous biologists interested in the physiology of tropical plants. The fabulous structural and functional diversity of tropical forests is still the major driver of research in this field. Classical physiological work involving tropical plants, such as the discovery of C4 photosynthesis in sugarcane, is invoked to exemplify the historical and current importance of physiological research in the tropics, and its applications in agriculture, forestry and conservation. An historical background describing the early and more recent development of a tradition on the physiological study of tropical plants is followed by a summary of the research conducted on the physiology of tropical crops. Common areas of interest and influence between the fields of crop physiology and plant ecophysiology are identified and exemplified with problems on the environmental physiology of crops like coffee and cassava. The physiology of tropical forest plants is discussed in terms of its contributions to general plant physiological knowledge in areas such as photosynthetic metabolism and plant water relations. Despite the impressive technical advances achieved during the past decade, the importance of continuous development of appropriate instrumentation to study and measure the physiology of plants in situ is stressed. Although the basic metabolic processes that underlie the mechanisms of plant responses to the environment are probably highly conserved and qualitatively similar among tropical and temperate plants, it is also apparent that tropical plants exhibit metabolic peculiarities. These include aspects of photosynthetic metabolism, phloem transport physiology, sensitivity to low temperatures, reproduction, responses to climatic seasonality, and a

Contaminants in tropical island streams and their biota.

Science.gov (United States)

Buttermore, Elissa N; Cope, W Gregory; Kwak, Thomas J; Cooney, Patrick B; Shea, Damian; Lazaro, Peter R

2018-02-01

in similar tropical islands elsewhere with information needed to guide ecosystem and fisheries conservation and management and human health risk assessment. Copyright © 2017 Elsevier Inc. All rights reserved.

Contaminants in tropical island streams and their biota

Science.gov (United States)

Buttermore, Elissa N.; Cope, W. Gregory; Kwak, Thomas J.; Cooney, Patrick B.; Shea, Damian; Lazaro, Peter R.

2018-01-01

streams and biota and provide natural resource and public health agencies here and in similar tropical islands elsewhere with information needed to guide ecosystem and fisheries conservation and management and human health risk assessment.

An estimate of the number of tropical tree species

DEFF Research Database (Denmark)

Slik, J. W Ferry; Arroyo-Rodríguez, Víctor; Aiba, Shin Ichiro

2015-01-01

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, ...

Teleconnections from Tropics to Northern Extratropics through a Southerly Conveyor

OpenAIRE

Wang, Zhuo; Chang, C.-P.; Wang, Bin; Jin, Fei-fei

2005-01-01

Rossby wave propagation theory predicts that Rossby waves in a tropical easterly flow cannot escape from the Tropics to the extratropics. Here the authors show that a southerly flow component in the basic state (a southerly conveyor) may transfer a Rossby wave source northward; thus, a forcing embedded in the deep tropical easterlies may excite a Rossby wave response in the extratropical westerlies. It is shown that the southerly conveyor determines the location of the effective R...

Damage-controlled logging in managed tropical rain forest in Suriname

OpenAIRE

Hendrison, J.

1990-01-01

Concern about worldwide deforestation and exploitation of the tropical rain forests has led to friction between national governments, wood industries and timber trade on the one hand, and scientists and environmental organizations on the other. One way to safeguard the tropical rain forests is to avoid human interference and to use forests only as nature reserves and as buffer zones of environmental protection. Some vulnerable tropical rain forests and those with unique flora and fau...

A Probabilistic Approach to Tropical Cyclone Conditions of Readiness (TCCOR)

National Research Council Canada - National Science Library

Wallace, Kenneth A

2008-01-01

Tropical Cyclone Conditions of Readiness (TCCOR) are set at DoD installations in the Western Pacific to convey the risk associated with the onset of destructive winds from approaching tropical cyclones...

[Tropical causes of epilepsy].

Science.gov (United States)

Carod-Artal, F J

Eighty-five percent of all epileptics live in tropical regions. Prenatal risk factors, traumatic brain injuries and different parasitic infestations of the central nervous system (CNS) are the reasons behind the high prevalence of epilepsy. This work reviews the main parasitic infestations causing epilepsy in the tropics. Neurocysticercosis is the main cause of focal epilepsy in early adulthood in endemic areas (30-50%). All the phases of cysticerci (viable, transitional and calcified) are associated with epileptic seizures. Anti-cysticercus treatment helps get rid of cysticerci faster and reduces the risk of recurrence of seizures in patients with viable cysts. Symptomatic epilepsy can be the first manifestation of neuroschistosomiasis in patients without any systemic symptoms. The pseudotumoral form can trigger seizures secondary to the presence of granulomas and oedemas in the cerebral cortex. The eggs of Schistosoma japonicum are smaller, reach the CNS more easily and trigger epileptic seizures more frequently. Toxocariasis and sparganosis are other parasitic infestations that can give rise to symptomatic seizures. The risk factors for suffering chronic epilepsy after cerebral malaria are a positive familial history of epilepsy and a history of episodes of fever and cerebral malaria that began with coma or which progressed with multiple, prolonged epileptic seizures. About 20% of patients with cerebral infarction secondary to Chagas disease present late vascular epilepsy as a complication. Very few studies have been conducted to examine the prognosis, risk of recurrence and modification of the natural course of seizures associated with tropical parasitic infestations, except for the case of neurocysticercosis.

Review of Tropical-Extratropical Teleconnections on Intraseasonal Time Scales

Science.gov (United States)

Stan, Cristiana; Straus, David M.; Frederiksen, Jorgen S.; Lin, Hai; Maloney, Eric D.; Schumacher, Courtney

2017-12-01

The interactions and teleconnections between the tropical and midlatitude regions on intraseasonal time scales are an important modulator of tropical and extratropical circulation anomalies and their associated weather patterns. These interactions arise due to the impact of the tropics on the extratropics, the impact of the midlatitudes on the tropics, and two-way interactions between the regions. Observational evidence, as well as theoretical studies with models of complexity ranging from the linear barotropic framework to intricate Earth system models, suggest the involvement of a myriad of processes and mechanisms in generating and maintaining these interconnections. At this stage, our understanding of these teleconnections is primarily a collection of concepts; a comprehensive theoretical framework has yet to be established. These intraseasonal teleconnections are increasingly recognized as an untapped source of potential subseasonal predictability. However, the complexity and diversity of mechanisms associated with these teleconnections, along with the lack of a conceptual framework to relate them, prevent this potential predictability from being translated into realized forecast skill. This review synthesizes our progress in understanding the observed characteristics of intraseasonal tropical-extratropical interactions and their associated mechanisms, identifies the significant gaps in this understanding, and recommends new research endeavors to address the remaining challenges.

Why tropical forest lizards are vulnerable to climate warming

Science.gov (United States)

Huey, Raymond B.; Deutsch, Curtis A.; Tewksbury, Joshua J.; Vitt, Laurie J.; Hertz, Paul E.; Álvarez Pérez, Héctor J.; Garland, Theodore

2009-01-01

Biological impacts of climate warming are predicted to increase with latitude, paralleling increases in warming. However, the magnitude of impacts depends not only on the degree of warming but also on the number of species at risk, their physiological sensitivity to warming and their options for behavioural and physiological compensation. Lizards are useful for evaluating risks of warming because their thermal biology is well studied. We conducted macrophysiological analyses of diurnal lizards from diverse latitudes plus focal species analyses of Puerto Rican Anolis and Sphaerodactyus. Although tropical lowland lizards live in environments that are warm all year, macrophysiological analyses indicate that some tropical lineages (thermoconformers that live in forests) are active at low body temperature and are intolerant of warm temperatures. Focal species analyses show that some tropical forest lizards were already experiencing stressful body temperatures in summer when studied several decades ago. Simulations suggest that warming will not only further depress their physiological performance in summer, but will also enable warm-adapted, open-habitat competitors and predators to invade forests. Forest lizards are key components of tropical ecosystems, but appear vulnerable to the cascading physiological and ecological effects of climate warming, even though rates of tropical warming may be relatively low. PMID:19324762

The importance of precessional signals in the tropical climate

Energy Technology Data Exchange (ETDEWEB)

Clement, A C [Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 (United States); Hall, A [UCLA, 7955 Math Sciences Building, 405 Hilgard Ave., Box 951565, Los Angeles, CA 90095 (United States); Broccoli, A J [Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901-8551 (United States)

2004-04-01

Past research on the climate response to orbital forcing has emphasized the glacial-interglacial variations in global ice volume, global-mean temperature, and the global hydrologic cycle. This emphasis may be inappropriate in the tropics, where the response to precessional forcing is likely to be somewhat independent of the glacial-interglacial variations, particularly in variables relating to the hydrologic cycle. To illustrate this point, we use an atmospheric general circulation model coupled to a slab ocean model, performing experiments that quantify the tropical climate's response to (1) opposite phases of precessional forcing, and (2) Last Glacial Maximum boundary conditions. While the glacially-forced tropical temperature changes are typically more than an order of magnitude larger than those arising from precessional forcing, the hydrologic signals stemming from the two forcings are comparable in magnitude. The mechanisms behind these signals are investigated and shown to be quite distinct for the precessional and glacial forcing. Because of strong dynamical linkages in the tropics, the model results illustrate the impossibility of predicting the local hydrologic response to external forcing without understanding the response at much larger spatial scales. Examples from the paleoclimate record are presented as additional evidence for the importance of precessional signals in past variations of the tropical climate. (orig.)

Tropical Atlantic-Korea teleconnection pattern during boreal summer season

Science.gov (United States)

Ham, Yoo-Geun; Chikamoto, Yoshimitsu; Kug, Jong-Seong; Kimoto, Masahide; Mochizuki, Takashi

2017-10-01

The remote impact of tropical Atlantic sea surface temperature (SST) variability on Korean summer precipitation is examined based on observational data analysis along with the idealized and hindcast model experiments. Observations show a significant correlation (i.e. 0.64) between Korean precipitation anomalies (averaged over 120-130°E, 35-40°N) and the tropical Atlantic SST index (averaged over 60°W-20°E, 30°S-30°N) during the June-July-August (JJA) season for the 1979-2010 period. Our observational analysis and partial-data assimilation experiments using the coupled general circulation model demonstrate that tropical Atlantic SST warming induces the equatorial low-level easterly over the western Pacific through a reorganization of the global Walker Circulation, causing a decreased precipitation over the off-equatorial western Pacific. As a Gill-type response to this diabatic forcing, an anomalous low-level anticyclonic circulation appears over the Philippine Sea, which transports wet air from the tropics to East Asia through low-level southerly, resulting an enhanced precipitation in the Korean peninsula. Multi-model hindcast experiments also show that predictive skills of Korean summer precipitation are improved by utilizing predictions of tropical Atlantic SST anomalies as a predictor for Korean precipitation anomalies.

Ocean-atmosphere forcing of South American tropical paleoclimate, LGM to present

Science.gov (United States)

Baker, P. A.; Fritz, S. C.; Dwyer, G. S.; Rigsby, C. A.; Silva, C. G.; Burns, S. J.

2012-12-01

Because of many recent terrestrial paleoclimatic and marine paleoceanographic records, late Quaternary South American tropical paleoclimate is as well understood as that anywhere in the world. While lessons learned from the recent instrumental record of climate are informative, this record is too short to capture much of the lower frequency variability encountered in the paleoclimate records and much of the observed paleoclimate is without modern analogue. This paleoclimate is known to be regionally variable with significant differences both north and south of the equator and between the western high Andes and eastern lowlands of the Amazon and Nordeste Brazil. Various extrinsic forcing mechanisms affected climate throughout the period, including global concentrations of GHGs, Northern Hemisphere ice sheet forcing, seasonal insolation forcing of the South American summer monsoon (SASM), millennial-scale Atlantic forcing, and Pacific forcing of the large-scale Walker circulation. The magnitude of the climate response to these forcings varied temporally, largely because of the varying amplitude of the forcing itself. For example, during the last glacial, large-amplitude north Atlantic forcing during Heinrich 1 and the LGM itself, led to wet (dry) conditions south (north) of the equator. During the Holocene, Atlantic forcing was lower amplitude, thus seasonal insolation forcing generally predominated with a weaker-than-normal SASM during the early Holocene resulting in dry conditions in the south-western tropics and wet conditions in the eastern lowlands and Nordeste; in the late Holocene seasonal insolation reached a maximum in the southern tropics and climate conditions reversed.

Insects associated with tropical foliage produced in the coffee growing region of Colombia

Directory of Open Access Journals (Sweden)

Luis F. Aristizábal

2013-09-01

Full Text Available We conducted a survey of insects and pest management practices on 34 farms growing ornamental tropical foliage plants in the central coffee region of Colombia over two years. Tropical foliage provided habitat for a diverse range of insects. In total, phytophagous or detritivorous insects from six orders, 40 families and 62 genera were collected. The most common were Hemiptera (29 genera from 16 families, followed by Coleoptera (17 genera from 4 families, Diptera (5 genera from 5 families, Lepidoptera (5 genera from 4 families, Hymenoptera (3 genera from 2 families and Orthoptera (2 genera from 2 families. The most common phytophagous species were leaf cutting ants (Atta and Acromyrmex spp., leaf beetles (Chrysomelidae, leafhoppers (Cicadellidae, stinkbugs (Pentatomidae, squash bugs (Coreidae, tree hoppers (Membracidae and plant hoppers (Fulgoridae. Beneficial insects identified from tropical foliage included predators and parasitoids amongst 5 orders, 12 families and 22 genera. The most abundant were predators among the Coccinellidae, Chrysopidae, Reduviidae, Lycidae and Formicidae but only low numbers of parasitoids (Ichneumonidae, Braconidae and Tachinidae were collected. A pest management questionnaire given to growers revealed a preponderance of reliance on broad spectrum insecticides with a smaller number of growers (approximately one third also using some biological control methods. Our survey contributes basic information regarding diversity of Neotropical insects associated with ornamental foliage plants.

Statistical strategies for global monitoring of tropical forests

Science.gov (United States)

Raymond L. Czaplewski

1991-01-01

The Food and Agricultural Organization (FAO) of the United Nations is conducting a global assessment of tropical forest resources, which will be accomplished by mid-1992. This assessment requires, in part, estimates of the total area of tropical forest cover in 1990, and the rate of change in forest cover between 1980 and 1990. This paper describes: (1) the strategic...

Sherlock Holmes and tropical medicine: a centennial appraisal.

Science.gov (United States)

Sodeman, W A

1994-01-01

Sir Arthur Conan Doyle incorporated an unidentified tropical disease as a murder weapon in the Sherlock Holmes story, "The Dying Detective," written in 1913. Documentary and circumstantial evidence suggests that the disease mentioned was melioidosis. The description of the newly identified disease occurred shortly before Doyle's death. Doyle's other works at the time reflect a consistent interest in tropical disease.

Environmental stewardship for gold mining in tropical regions

Directory of Open Access Journals (Sweden)

A Isahak

2013-10-01

Full Text Available Mining has gained strong popularity in recent years due to the increase in global demand for metals and other industrial raw material derived from the ground. However, information and good governance regarding activities related to mining is still very much lacking especially in underdeveloped and developing countries in the tropics. In Malaysia, the importance of environmental stewardship in mining is a new phenomenon. The new National Mineral Policy 2 calls for compliance with existing standards and guidelines, stresses on progressive and post mining rehabilitation as well as promotes the gathering and dissemination of information, best mining practices, public disclosure and corporate social responsibility. Our preliminary studies however have shown that its implementation may have been hampered by inadequate legal and administrative structures, lack of freedom of information, physical inaccessibility, lack of information and public participation. In this presentation, the above issues and measures to reduce the impact of mining, particularly that of gold on the environment with a special focus on Malaysia is discussed. These measures include alternative gold extraction methods, appropriate tailing dam construction and management, health risk assessment and risk management, compliance with the Cyanide Code and liberalization of access to information, facilitation of access to justice, the strengthening of legal and administrative structures as well as corporate accountability to the public as part of corporate social responsibility.

Tropical countries may be willing to pay more to protect their forests

Science.gov (United States)

Vincent, Jeffrey R.; Carson, Richard T.; DeShazo, J. R.; Schwabe, Kurt A.; Ahmad, Ismariah; Chong, Siew Kook; Chang, Yii Tan; Potts, Matthew D.

2014-01-01

Inadequate funding from developed countries has hampered international efforts to conserve biodiversity in tropical forests. We present two complementary research approaches that reveal a significant increase in public demand for conservation within tropical developing countries as those countries reach upper-middle-income (UMI) status. We highlight UMI tropical countries because they contain nearly four-fifths of tropical primary forests, which are rich in biodiversity and stored carbon. The first approach is a set of statistical analyses of various cross-country conservation indicators, which suggests that protective government policies have lagged behind the increase in public demand in these countries. The second approach is a case study from Malaysia, which reveals in a more integrated fashion the linkages from rising household income to increased household willingness to pay for conservation, nongovernmental organization activity, and delayed government action. Our findings suggest that domestic funding in UMI tropical countries can play a larger role in (i) closing the funding gap for tropical forest conservation, and (ii) paying for supplementary conservation actions linked to international payments for reduced greenhouse gas emissions from deforestation and forest degradation in tropical countries. PMID:24982171

Structural Dynamics of Tropical Moist Forest Gaps

Science.gov (United States)

Hunter, Maria O.; Keller, Michael; Morton, Douglas; Cook, Bruce; Lefsky, Michael; Ducey, Mark; Saleska, Scott; de Oliveira, Raimundo Cosme; Schietti, Juliana

2015-01-01

Gap phase dynamics are the dominant mode of forest turnover in tropical forests. However, gap processes are infrequently studied at the landscape scale. Airborne lidar data offer detailed information on three-dimensional forest structure, providing a means to characterize fine-scale (1 m) processes in tropical forests over large areas. Lidar-based estimates of forest structure (top down) differ from traditional field measurements (bottom up), and necessitate clear-cut definitions unencumbered by the wisdom of a field observer. We offer a new definition of a forest gap that is driven by forest dynamics and consistent with precise ranging measurements from airborne lidar data and tall, multi-layered tropical forest structure. We used 1000 ha of multi-temporal lidar data (2008, 2012) at two sites, the Tapajos National Forest and Ducke Reserve, to study gap dynamics in the Brazilian Amazon. Here, we identified dynamic gaps as contiguous areas of significant growth, that correspond to areas > 10 m2, with height gap at Tapajos National Forest (4.8 %) as compared to Ducke Reserve (2.0 %). On average, gaps were smaller at Ducke Reserve and closed slightly more rapidly, with estimated height gains of 1.2 m y-1 versus 1.1 m y-1 at Tapajos. At the Tapajos site, height growth in gap centers was greater than the average height gain in gaps (1.3 m y-1 versus 1.1 m y-1). Rates of height growth between lidar acquisitions reflect the interplay between gap edge mortality, horizontal ingrowth and gap size at the two sites. We estimated that approximately 10 % of gap area closed via horizontal ingrowth at Ducke Reserve as opposed to 6 % at Tapajos National Forest. Height loss (interpreted as repeat damage and/or mortality) and horizontal ingrowth accounted for similar proportions of gap area at Ducke Reserve (13 % and 10 %, respectively). At Tapajos, height loss had a much stronger signal (23 % versus 6 %) within gaps. Both sites demonstrate limited gap contagiousness defined by an

Diversity of Platygastridae in Leaf Litter and Understory Layers of Tropical Rainforests of the Western Ghats Biodiversity Hotspot, India.

Science.gov (United States)

Manoj, K; Rajesh, T P; Prashanth Ballullaya, U; Meharabi, K M; Shibil, V K; Rajmohana, K; Sinu, Palatty Allesh

2017-06-01

Platygastridae is the third largest family of parasitic Hymenoptera in the world. It includes important egg and larval parasitoids of insects and spiders. Therefore, Platygastridae is functionally important in maintaining the stability of tropical rainforests and agroecosystems. Although the diversity of Platygastridae is relatively well-known in agroecosystems, we know little about their diversity in tropical rainforests, and particularly about that of the leaf litter layer. Here, we address the importance of monitoring Platygastridae in tropical rainforests, using data from the relic primary forests of the sacred groves of the Western Ghats. First, we demonstrate that pitfall traps allow us to catch a wide array of representative diversity of Platygastridae of the tropical rainforests, and we establish an efficient collection method to study Platygastridae of leaf litter layer. Second, we demonstrate that the community structure and composition of Platygastridae of the leaf litter layer is different from that seen in the understory of the forests. This indirectly informs us that the Malaise traps capture only a minor subset of the species active in the rainforests. Third, we find that the dry and wet seasons captured dissimilar community of Platygastridae, suggesting that the season might alter the potential host species or host stages. We conclude that monitoring parasitic Hymenoptera in the leaf litter layer of tropical rainforests can provide fresh insights on the species distribution of both the parasitoids and their hosts, and allows us to examine the current state of the tropical rainforests from a functional point of view. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Nuclear power plant risk from tropical cyclones

International Nuclear Information System (INIS)

Gilmore, T.F.

1991-01-01

Tropical cyclones are considered to have a potential for contributing to the overall core-melt frequency at Turkey Point. A tropical cyclone is known to have the four main hazards associated with it: wind, tidal surge, wind-generated missiles, and precipitation. To understand the contribution to overall core-melt risk at Turkey Point, it is essential to understand the mechanisms of these hazards and their relative importance. The results are bounded by the hurricane surge scenario, where the frequency of core melt is equal to the frequency of the surge reaching 19 ft NGVD (National Geographic Vertical Datum). This could be mitigated by potential recovery actions for the tropical cyclone scenario. The probability of the storm surge reaching 19 ft NVGD is estimated to be 1 x 10 -4 . The data associated with the tropical cyclones as discussed in detail in the body of this paper are lacking in quantity and quality. By taking the conservative approach in creating the wind/frequency, wind/surge, and surge/frequency relationships, the conclusion that the results are worst case is reasonable. With this in mind, it is logical to conclude that the value of further hazard analysis to narrow down the built-in conservative margin using the existing data and technology is doubtful. Thus, a recovery approach to driving the risk level down is the most pragmatic step to be taken

Hydrological structure and biological productivity of the tropical Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Muraleedharan, U.D.; Muraleedharan, P.M.

Hydrological structure analyses of regions in the tropical Atlantic Ocean have consistently revealed the existence of a typical tropical structure characterized by a nitrate-depleted mixed layer above the thermocline. The important biological...

The Economics of Smallholder Organic Contract Farming in Tropical Africa

DEFF Research Database (Denmark)

Bolwig, Simon; Gibbon, Peter; Jones, Edward Samuel

2009-01-01

The paper examines the revenue effects of certified organic contract farming for smallholders and of adoption of organic agricultural farming methods in a tropical African context. The comparison in both cases is with farming systems that are "organic by default." Survey data from a large organic...... coffee contract farming scheme in Uganda are reported and analyzed using a standard OLS regression and a full information maximum likelihood (FIML) estimate of the Heckman selection model. The analysis finds that, controlling for a range of factors, there are positive revenue effects both from...... participation in the scheme and, more modestly, from applying organic farming techniques....

Tropical wetlands: A missing link in the global carbon cycle?

Science.gov (United States)

Sjögersten, Sofie; Black, Colin R; Evers, Stephanie; Hoyos-Santillan, Jorge; Wright, Emma L; Turner, Benjamin L

2014-01-01

Tropical wetlands are not included in Earth system models, despite being an important source of methane (CH4) and contributing a large fraction of carbon dioxide (CO2) emissions from land use, land use change, and forestry in the tropics. This review identifies a remarkable lack of data on the carbon balance and gas fluxes from undisturbed tropical wetlands, which limits the ability of global change models to make accurate predictions about future climate. We show that the available data on in situ carbon gas fluxes in undisturbed forested tropical wetlands indicate marked spatial and temporal variability in CO2 and CH4 emissions, with exceptionally large fluxes in Southeast Asia and the Neotropics. By upscaling short-term measurements, we calculate that approximately 90 ± 77 Tg CH4 year−1 and 4540 ± 1480 Tg CO2 year−1 are released from tropical wetlands globally. CH4 fluxes are greater from mineral than organic soils, whereas CO2 fluxes do not differ between soil types. The high CO2 and CH4 emissions are mirrored by high rates of net primary productivity and litter decay. Net ecosystem productivity was estimated to be greater in peat-forming wetlands than on mineral soils, but the available data are insufficient to construct reliable carbon balances or estimate gas fluxes at regional scales. We conclude that there is an urgent need for systematic data on carbon dynamics in tropical wetlands to provide a robust understanding of how they differ from well-studied northern wetlands and allow incorporation of tropical wetlands into global climate change models. PMID:26074666

A stable isotope-based approach to tropical dendroclimatology

Science.gov (United States)

Evans, Michael N.; Schrag, Daniel P.

2004-08-01

We describe a strategy for development of chronological control in tropical trees lacking demonstrably annual ring formation, using high resolution δ 18O measurements in tropical wood. The approach applies existing models of the oxygen isotopic composition of alpha-cellulose (Roden et al., 2000), a rapid method for cellulose extraction from raw wood (Brendel et al., 2000), and continuous flow isotope ratio mass spectrometry (Brenna et al., 1998) to develop proxy chronological, rainfall and growth rate estimates from tropical trees lacking visible annual ring structure. Consistent with model predictions, pilot datasets from the temperate US and Costa Rica having independent chronological control suggest that observed cyclic isotopic signatures of several permil (SMOW) represent the annual cycle of local rainfall and relative humidity. Additional data from a plantation tree of known age from ENSO-sensitive northwestern coastal Peru suggests that the 1997-8 ENSO warm phase event was recorded as an 8‰ anomaly in the δ 18O of α-cellulose. The results demonstrate reproducibility of the stable isotopic chronometer over decades, two different climatic zones, and three tropical tree genera, and point to future applications in paleoclimatology.

Ducting Conditions for Electromagnetic Wave Propagation in Tropical Disturbances from GPS Dropsonde Data

Science.gov (United States)

2013-12-01

depression, tropical storm , hurricane, extratropical cyclone, subtropical depression, subtropical storm , a low of no category, tropical wave, disturbance or...surface-based ducts, and elevated ducts. We further separate the duct occurrence based on the location relative to their respective storms . Based...on the number of soundings in different types of tropical disturbances, we chose to further analyze duct conditions in hurricanes and tropical storms

Impacts of different grades of tropical cyclones on infectious diarrhea in Guangdong, 2005-2011.

Directory of Open Access Journals (Sweden)

Ruihua Kang

Full Text Available Guangdong province is one of the most vulnerable provinces to tropical cyclones in China. Most prior studies concentrated on the relationship between tropical cyclones and injuries and mortality. This study aimed to explore the impacts of different grades of tropical cyclones on infectious diarrhea incidence in Guangdong province, from 2005 to 2011.Mann-Whitney U test was firstly used to examine if infectious diarrhea were sensitive to tropical cyclone. Then unidirectional 1:1 case-crossover design was performed to quantitatively evaluate the relationship between daily number of infectious diarrhea and tropical cyclone from 2005 to 2011 in Guangdong, China. Principal component analysis (PCA was applied to eliminate multicollinearity. Multivariate logistic regression model was used to estimate the hazard ratios (HRs and the 95% confidence intervals (CI.There were no significant relationships between tropical cyclone and bacillary dysentery, amebic dysentery, typhoid, and paratyphoid cases. Infectious diarrhea other than cholera, dysentery, typhoid and paratyphoid significantly increased after tropical cyclones. The strongest effect were shown on lag 1 day (HRs = 1.95, 95%CI = 1.22, 3.12 and no lagged effect was detected for tropical depression, tropical storm, severe tropical storm and typhoon, with the largest HRs (95%CI of 2.16 (95%CI = 1.69, 2.76, 2.43 (95%CI = 1.65, 3.58 and 2.21 (95%CI = 1.65, 2.69, respectively. Among children below 5 years old, the impacts of all grades of tropical cyclones were strongest at lag 0 day. And HRs were 2.67 (95%CI = 1.10, 6.48, 2.49 (95%CI = 1.80, 3.44, 4.89 (95%CI = 2.37, 7.37 and 3.18 (95%CI = 2.10, 4.81, respectively.All grades of tropical cyclones could increase risk of other infectious diarrhea. Severe tropical storm has the strongest influence on other infectious diarrhea. The impacts of tropical cyclones on children under 5 years old were higher than total population.

Quantitative Analysis of Complex Tropical Forest Stands: A Review ...

African Journals Online (AJOL)

The importance of data analysis in quantitative assessment of natural resources remains significant in the sustainable management of complex tropical forest resources. Analyses of data from complex tropical forest stands have not been easy or clear due to improper data management. It is pivotal to practical researches ...

Understanding the geographic distribution of tropical cyclone formation for applications in climate models

Science.gov (United States)

Tory, Kevin J.; Ye, H.; Dare, R. A.

2018-04-01

Projections of Tropical cyclone (TC) formation under future climate scenarios are dependent on climate model simulations. However, many models produce unrealistic geographical distributions of TC formation, especially in the north and south Atlantic and eastern south Pacific TC basins. In order to improve confidence in projections it is important to understand the reasons behind these model errors. However, considerable effort is required to analyse the many models used in projection studies. To address this problem, a novel diagnostic is developed that provides compelling insight into why TCs form where they do, using a few summary diagrams. The diagnostic is developed after identifying a relationship between seasonal climatologies of atmospheric variables in 34 years of ECMWF reanalysis data, and TC detection distributions in the same data. Geographic boundaries of TC formation are constructed from four threshold quantities. TCs form where Emanuel's Maximum Potential Intensity, V_{{PI}}, exceeds 40 {ms}^{{ - 1}}, 700 hPa relative humidity, RH_{{700}}, exceeds 40%, and the magnitude of the difference in vector winds between 850 and 200 hPa, V_{{sh}}, is less than 20 {ms}^{{ - 1}}. The equatorial boundary is best defined by a composite quantity containing the ratio of absolute vorticity (η ) to the meridional gradient of absolute vorticity (β ^{*}), rather than η alone. {β ^*} is also identified as a potentially important ingredient for TC genesis indices. A comparison of detected Tropical Depression (TD) and Tropical Storm (TS) climatologies revealed TDs more readily intensify further to TS where {V_{PI}} is elevated and {V_{sh}} is relatively weak. The distributions of each threshold quantity identify the factors that favour and suppress TC formation throughout the tropics in the real world. This information can be used to understand why TC formation is poorly represented in some climate models, and shows potential for understanding anomalous TC formation

Coupled nutrient cycling determines tropical forest trajectory under elevated CO2.

Science.gov (United States)

Bouskill, N.; Zhu, Q.; Riley, W. J.

2017-12-01

Tropical forests have a disproportionate capacity to affect Earth's climate relative to their areal extent. Despite covering just 12 % of land surface, tropical forests account for 35 % of global net primary productivity and are among the most significant of terrestrial carbon stores. As atmospheric CO2 concentrations increase over the next century, the capacity of tropical forests to assimilate and sequester anthropogenic CO2 depends on limitation by multiple factors, including the availability of soil nutrients. Phosphorus availability has been considered to be the primary factor limiting metabolic processes within tropical forests. However, recent evidence points towards strong spatial and temporal co-limitation of tropical forests by both nitrogen and phosphorus. Here, we use the Accelerated Climate Modeling for Energy (ACME) Land Model (ALMv1-ECA-CNP) to examine how nutrient cycles interact and affect the trajectory of the tropical forest carbon sink under, (i) external nutrient input, (ii) climate (iii) elevated CO2, and (iv) a combination of 1-3. ALMv1 includes recent theoretical advances in representing belowground competition between roots, microbes and minerals for N and P uptake, explicit interactions between the nitrogen and phosphorus cycles (e.g., phosphatase production and nitrogen fixation), the dynamic internal allocation of plant N and P resources, and the integration of global datasets of plant physiological traits. We report nutrient fertilization (N, P, N+P) predictions for four sites in the tropics (El Verde, Puerto Rico, Barro Colorado Island, Panama, Manaus, Brazil and the Osa Peninsula, Coast Rica) to short-term nutrient fertilization (N, P, N+P), and benchmarking of the model against a meta-analysis of forest fertilization experiments. Subsequent simulations focus on the interaction of the carbon, nitrogen, and phosphorus cycles across the tropics with a focus on the implications of coupled nutrient cycling and the fate of the tropical

Integrating and Visualizing Tropical Cyclone Data Using the Real Time Mission Monitor

Science.gov (United States)

Goodman, H. Michael; Blakeslee, Richard; Conover, Helen; Hall, John; He, Yubin; Regner, Kathryn

2009-01-01

The Real Time Mission Monitor (RTMM) is a visualization and information system that fuses multiple Earth science data sources, to enable real time decision-making for airborne and ground validation experiments. Developed at the NASA Marshall Space Flight Center, RTMM is a situational awareness, decision-support system that integrates satellite imagery, radar, surface and airborne instrument data sets, model output parameters, lightning location observations, aircraft navigation data, soundings, and other applicable Earth science data sets. The integration and delivery of this information is made possible using data acquisition systems, network communication links, network server resources, and visualizations through the Google Earth virtual globe application. RTMM is extremely valuable for optimizing individual Earth science airborne field experiments. Flight planners, scientists, and managers appreciate the contributions that RTMM makes to their flight projects. A broad spectrum of interdisciplinary scientists used RTMM during field campaigns including the hurricane-focused 2006 NASA African Monsoon Multidisciplinary Analyses (NAMMA), 2007 NOAA-NASA Aerosonde Hurricane Noel flight, 2007 Tropical Composition, Cloud, and Climate Coupling (TC4), plus a soil moisture (SMAP-VEX) and two arctic research experiments (ARCTAS) in 2008. Improving and evolving RTMM is a continuous process. RTMM recently integrated the Waypoint Planning Tool, a Java-based application that enables aircraft mission scientists to easily develop a pre-mission flight plan through an interactive point-and-click interface. Individual flight legs are automatically calculated "on the fly". The resultant flight plan is then immediately posted to the Google Earth-based RTMM for interested scientists to view the planned flight track and subsequently compare it to the actual real time flight progress. We are planning additional capabilities to RTMM including collaborations with the Jet Propulsion

Tropical Journal of Pharmaceutical Research

African Journals Online (AJOL)

We seek to encourage pharmaceutical and allied research of tropical and ... and related disciplines (including biotechnology, cell and molecular biology, drug ... with ibrutinib reduces proliferation, migration and invasion of lung cancer cells ...

Concurrent malaria and typhoid fever in the tropics: the diagnostic challenges and public health implications.

Science.gov (United States)

Uneke, C J

2008-06-01

Malaria and typhoid fever still remain diseases of major public health importance in the tropics. Individuals in areas endemic for both the diseases are at substantial risk of contracting both these diseases, either concurrently or an acute infection superimposed on a chronic one. The objective of this report was to systematically review scientific data from studies conducted in the tropics on concurrent malaria and typhoid fever within the last two decades (1987-2007), to highlight the diagnostic challenges and the public health implications. Using the MedLine Entrez-PubMed search, relevant publications were identified for the review via the key words Malaria and Typhoid fever, which yielded 287 entries as of January 2008. Most of the studies reviewed expressed concern that poor diagnosis continues to hinder effective control of concurrent malaria and typhoid fever in the tropics due to: non-specific clinical presentation of the diseases; high prevalence of asymptomatic infections; lack of resources and insufficient access to trained health care providers and facilities; and widespread practice of self-treatment for clinically suspected malaria or typhoid fever. There were considerably higher rates of concurrent malaria and typhoid fever by Widal test compared to the bacteriological culture technique. Although culture technique remains the gold standard in typhoid fever diagnosis, Widal test is still of significant diagnostic value provided judicious interpretation of the test is made against a background of pertinent information. Malaria could be controlled through interventions to minimize human-vector contact, while improved personal hygiene, targeted vaccination campaigns and intensive community health education could help to control typhoid fever in the tropics.

Anomalous cold in the Pangaean tropics

Science.gov (United States)

Soreghan, G.S.; Soreghan, M.J.; Poulsen, C.J.; Young, R.A.; Eble, C.F.; Sweet, D.E.; Davogustto, O.C.

2008-01-01

The late Paleozoic archives the greatest glaciation of the Phanerozoic. Whereas high-latitude Gondwanan strata preserve widespread evidence for continental ice, the Permo-Carboniferous tropics have long been considered analogous to today's: warm and shielded from the highlatitude cold. Here, we report on glacial and periglacial indicators that record episodes of freezing continental temperatures in western equatorial Pangaea. An exhumed glacial valley and associated deposits record direct evidence for glaciation that extended to low paleoelevations in the ancestral Rocky Mountains. Furthermore, the Permo-Carboniferous archives the only known occurrence of widespread tropical loess in Earth's history; the volume, chemistry, and provenance of this loess(ite) is most consistent with glacial derivation. Together with emerging indicators for cold elsewhere in low-latitude Pangaea, these results suggest that tropical climate was not buffered from the high latitudes and may record glacial-interglacial climate shifts of very large magnitude. Coupled climate-ice sheet model simulations demonstrate that low atmospheric CO2 and solar luminosity alone cannot account for such cold, and that other factors must be considered in attempting to explain this 'best-known' analogue to our present Earth. ?? 2008 The Geological Society of America.

Tropical Hydroclimate Change during Heinrich Stadial 1: An Integrative Proxy-Model Synthesis

Science.gov (United States)

Lawman, A. E.; Sun, T.; Shanahan, T. M.; Di Nezio, P. N.; Gomez, K.; Piatrunia, N.; Sun, C.; Wu, X.; Kageyama, M.; Merkel, U.; Otto-Bliesner, B. L.; Abe-Ouchi, A.; Lohmann, G.; Singarayer, J. S.

2017-12-01

We explore the response of tropical climate to abrupt cooling of the North Atlantic (NA) during Heinrich Stadial 1 (HS1) combining paleoclimate proxies with model simulations. A total of 146 published paleoclimate records from tropical locations are used to categorize whether HS1 was wetter, drier, or unchanged relative to a deglacial baseline state. Only records with sufficient resolution to resolve HS1 and sufficient length to characterize the deglacial trend are considered. This synthesis reveals large-scale patterns of hydroclimate change relative to glacial conditions, confirming previously reported weaker Indian summer monsoon, a wetter southern Africa, and drying over the Caribbean. Our synthesis also reveals large-scale drying over the Maritime continent as well as wetter conditions in northern Australia and southern tropical South America. Our reinterpretation of the available proxy data reveals far more complexity and uncertainties for equatorial East Africa, a region that appears to straddle a pattern of dryer conditions to the north and wetter conditions to the south. Overall, these patterns of hydroclimate change depart from a southward shift of the Inter Tropical Convergence Zone (ITCZ), particularly outside the tropical Atlantic. We explore mechanisms driving these changes using a multi-model ensemble of "hosing" simulations performed relative to glacial conditions. The models show robust weakening of the Afro-Asian Monsoon, which we attribute to ventilation of colder mid-latitude air. Not all models simulate the remaining patterns inferred from the proxy data. The best-agreeing models indicate that cooling over the tropical NA and the Caribbean may be essential to communicate the response to the global tropics. This response can induce warming over the tropical South Atlantic via the wind-evaporation-SST feedback, driving wetter conditions in South Africa and tropical South America. Cooling over the Caribbean is communicated to the Pacific over the

Pyrrolizidine alkaloids in floral honeys of tropical Ghana: a health risk assessment.

Science.gov (United States)

Letsyo, Emmanuel; Jerz, Gerold; Winterhalter, Peter; Dübecke, Arne; von der Ohe, Werner; von der Ohe, Katharina; Beuerle, Till

2017-12-01

There is a vast amount of information about the nutritional and medicinal properties of honey as a result of its numerous benefits. However, honeys have been found to be contaminated with hepatotoxic and carcinogenic pyrrolizidine alkaloids (PAs) on account of bees foraging on PA-containing plants. This study deals with the analysis of PAs in tropical honeys emanating from different agro-ecological zones of Ghana in order to assess its potential health risk. PAs of 48 honey samples were analysed using high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The results show that a total of 85% of the honeys from various agro-ecological zones were PA positive including all honeys from supermarkets. The highest concentration of PAs was 2639 μg kg -1 , while the average PA concentration of the samples was 283 μg kg -1 . The study also found Chromolaena odorata pollens in majority of the honeys, thus indicating the plant as major source of PA contamination of honeys in the tropical regions.

Predicting tropical plant physiology from leaf and canopy spectroscopy.

Science.gov (United States)

Doughty, Christopher E; Asner, Gregory P; Martin, Roberta E

2011-02-01

A broad regional understanding of tropical forest leaf photosynthesis has long been a goal for tropical forest ecologists, but it has remained elusive due to difficult canopy access and high species diversity. Here we develop an empirical model to predict sunlit, light-saturated, tropical leaf photosynthesis using leaf and simulated canopy spectra. To develop this model, we used partial least squares (PLS) analysis on three tropical forest datasets (159 species), two in Hawaii and one at the biosphere 2 laboratory (B2L). For each species, we measured light-saturated photosynthesis (A), light and CO(2) saturated photosynthesis (A(max)), respiration (R), leaf transmittance and reflectance spectra (400-2,500 nm), leaf nitrogen, chlorophyll a and b, carotenoids, and leaf mass per area (LMA). The model best predicted A [r(2) = 0.74, root mean square error (RMSE) = 2.9 μmol m(-2) s(-1))] followed by R (r(2) = 0.48), and A(max) (r(2) = 0.47). We combined leaf reflectance and transmittance with a canopy radiative transfer model to simulate top-of-canopy reflectance and found that canopy spectra are a better predictor of A (RMSE = 2.5 ± 0.07 μmol m(-2) s(-1)) than are leaf spectra. The results indicate the potential for this technique to be used with high-fidelity imaging spectrometers to remotely sense tropical forest canopy photosynthesis.

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)

Informing and involving farmers in Benin

International Development Research Centre (IDRC) Digital Library (Canada)

IDRC

can do his or her part in addressing climate change.” The project is based on Benin's network of rural municipalities or “communes”. Meteorological pre-alert committees in. 35 municipalities will bring stakeholders together in collecting and sharing information on the risks of drought and tropical storms, among other hazards.

Analysis of Tropical Cyclone Tracks in the North Indian Ocean

Science.gov (United States)

Patwardhan, A.; Paliwal, M.; Mohapatra, M.

2011-12-01

Cyclones are regarded as one of the most dangerous meteorological phenomena of the tropical region. The probability of landfall of a tropical cyclone depends on its movement (trajectory). Analysis of trajectories of tropical cyclones could be useful for identifying potentially predictable characteristics. There is long history of analysis of tropical cyclones tracks. A common approach is using different clustering techniques to group the cyclone tracks on the basis of certain characteristics. Various clustering method have been used to study the tropical cyclones in different ocean basins like western North Pacific ocean (Elsner and Liu, 2003; Camargo et al., 2007), North Atlantic Ocean (Elsner, 2003; Gaffney et al. 2007; Nakamura et al., 2009). In this study, tropical cyclone tracks in the North Indian Ocean basin, for the period 1961-2010 have been analyzed and grouped into clusters based on their spatial characteristics. A tropical cyclone trajectory is approximated as an open curve and described by its first two moments. The resulting clusters have different centroid locations and also differently shaped variance ellipses. These track characteristics are then used in the standard clustering algorithms which allow the whole track shape, length, and location to be incorporated into the clustering methodology. The resulting clusters have different genesis locations and trajectory shapes. We have also examined characteristics such as life span, maximum sustained wind speed, landfall, seasonality, many of which are significantly different across the identified clusters. The clustering approach groups cyclones with higher maximum wind speed and longest life span in to one cluster. Another cluster includes short duration cyclonic events that are mostly deep depressions and significant for rainfall over Eastern and Central India. The clustering approach is likely to prove useful for analysis of events of significance with regard to impacts.

Tropical savannas and dry forests.

Science.gov (United States)

Pennington, R Toby; Lehmann, Caroline E R; Rowland, Lucy M

2018-05-07

In the tropics, research, conservation and public attention focus on rain forests, but this neglects that half of the global tropics have a seasonally dry climate. These regions are home to dry forests and savannas (Figures 1 and 2), and are the focus of this Primer. The attention given to rain forests is understandable. Their high species diversity, sheer stature and luxuriance thrill biologists today as much as they did the first explorers in the Age of Discovery. Although dry forest and savanna may make less of a first impression, they support a fascinating diversity of plant strategies to cope with stress and disturbance including fire, drought and herbivory. Savannas played a fundamental role in human evolution, and across Africa and India they support iconic megafauna. Copyright © 2018 Elsevier Ltd. All rights reserved.

Maximum covariance analysis to identify intraseasonal oscillations over tropical Brazil

Science.gov (United States)

Barreto, Naurinete J. C.; Mesquita, Michel d. S.; Mendes, David; Spyrides, Maria H. C.; Pedra, George U.; Lucio, Paulo S.

2017-09-01

A reliable prognosis of extreme precipitation events in the tropics is arguably challenging to obtain due to the interaction of meteorological systems at various time scales. A pivotal component of the global climate variability is the so-called intraseasonal oscillations, phenomena that occur between 20 and 100 days. The Madden-Julian Oscillation (MJO), which is directly related to the modulation of convective precipitation in the equatorial belt, is considered the primary oscillation in the tropical region. The aim of this study is to diagnose the connection between the MJO signal and the regional intraseasonal rainfall variability over tropical Brazil. This is achieved through the development of an index called Multivariate Intraseasonal Index for Tropical Brazil (MITB). This index is based on Maximum Covariance Analysis (MCA) applied to the filtered daily anomalies of rainfall data over tropical Brazil against a group of covariates consisting of: outgoing longwave radiation and the zonal component u of the wind at 850 and 200 hPa. The first two MCA modes, which were used to create the { MITB}_1 and { MITB}_2 indices, represent 65 and 16 % of the explained variance, respectively. The combined multivariate index was able to satisfactorily represent the pattern of intraseasonal variability over tropical Brazil, showing that there are periods of activation and inhibition of precipitation connected with the pattern of MJO propagation. The MITB index could potentially be used as a diagnostic tool for intraseasonal forecasting.

Evolution of Microsatellite Loci of Tropical and Temperate Anguilla Eels

Directory of Open Access Journals (Sweden)

Mei-Chen Tseng

2012-04-01

Full Text Available Anguilla eels are divided into temperate and tropical eels, based on their major distributions. The present study collected two temperate eels, Anguilla japonica and Anguilla anguilla, and two tropical eels, Anguilla marmorata and Anguilla bicolor pacifica, to examine two questions: do temperate and tropical Anguilla eels have different genetic polymorphic patterns?; and do temperate Anguilla japonica and Anguilla anguilla have a closer relationship to each other than to tropical eels? In total, 274 sequences were cloned and sequenced from six conserved microsatellite loci to examine polymorphic patterns of these four catadromous eels. Different mutational events, including substitutions, and repeat-unit deletions and insertions, appeared in major regions, while different point mutations were observed in flanking regions. The results implied that parallel patterns of microsatellite sequences occurred within both tropical and temperate freshwater eels. Consensus flanking sequences of six homologous loci from each of the four species were constructed. Genetic distances ranged from 0.044 (Anguilla bicolor pacifica vs. Anguilla marmorata to 0.061 (Anguilla marmorata vs. Anguilla anguilla. The tree topology suggests the hypothesis of Anguilla japonica and Anguilla anguilla being a sister group must be rejected.

Tropical wetlands and REDD+: Three unique scientific challenges for policy

Directory of Open Access Journals (Sweden)

Daniel A Friess

2013-07-01

Full Text Available The carbon sequestration and storage value of terrestrial habitats is now increasingly appreciated, and is the basis for Payment for Ecosystem Service (PES policies such as REDD+. Tropical wetlands may be suitable for inclusion in such schemes because of the disproportionately large volume of carbon they are able to store. However, tropical wetlands offer a number of unique challenges for carbon management and policy compared to terrestrial forest systems: 1 Tropical wetlands are dynamic and subject to a wide range of physical and ecological processes that affect their long-term carbon storage potential – thus, such systems can quickly become a carbon source instead of a sink; 2 Carbon dynamics in tropical wetlands often operate over longer time-scales than are currently covered by REDD+ payments; and 3 Much of the carbon in a tropical wetland is stored in the soil, so monitoring, reporting and verification (MRV needs to adequately encapsulate the entire ecosystem and not just the vegetative component. This paper discusses these physical and biological concepts, and highlights key legal, management and policy questions that must be considered when constructing a policy framework to conserve these crucial ecosystems.

Strategies and perspectives of influential environmental organizations toward tropical deforestation

International Nuclear Information System (INIS)

Ozanne, L.K.; Smith, P.M.

1993-01-01

In recent years, environmental nongovernment organizations (NGOs) have been active in alerting the public and governments to tropical forest issues. Many feel that these efforts have begun to affect the trade in tropical timber and influence the perceptions of logging in the tropics. However, the influence of environmental organizations is not restricted to tropical timber trade but has the potential to impact the global wood products industry. The wood products industry has an opportunity to address these pressures by understanding the strategies and perceptions of the environmental community on this issue and developing proactive strategies to deal with the situation. This study included a phase 1 prestudy, which reported the results of interview with over 39 environmental NGOs in both the US and Europe to develop an overview of this complex industry. A phase 2 followup fax questionnaire was administered to the most relevant US environmental NGOs in order to classify them on two important criteria: (1) their level of specialization; and (2) their organizational strategy. This paper provides an overview of the complex issues in the environmental debate regarding tropical deforestation and how environmental organizations are attempting to address these issues

Trailblazing the Carbon Cycle of Tropical Forests from Puerto Rico

Directory of Open Access Journals (Sweden)

Sandra Brown

2017-03-01

Full Text Available We review the literature that led to clarifying the role of tropical forests in the global carbon cycle from a time when they were considered sources of atmospheric carbon to the time when they were found to be atmospheric carbon sinks. This literature originates from work conducted by US Forest Service scientists in Puerto Rico and their collaborators. It involves the classification of forests by life zones, estimation of carbon density by forest type, assessing carbon storage changes with ecological succession and land use/land cover type, describing the details of the carbon cycle of forests at stand and landscape levels, assessing global land cover by forest type and the complexity of land use change in tropical regions, and assessing the ecological fluxes and storages that contribute to net carbon accumulation in tropical forests. We also review recent work that couples field inventory data, remote sensing technology such as LIDAR, and GIS analysis in order to more accurately determine the role of tropical forests in the global carbon cycle and point out new avenues of carbon research that address the responses of tropical forests to environmental change.

DETERMINING HOT SPOTS OF FECAL CONTAMINATION IN A TROPICAL WATERSHED BY COMBINING LAND-USE INFORMATION AND METEOROLOGICAL DATA WITH SOURCE-SPECIFIC ASSAYS

Science.gov (United States)

Microbial source tracking (MST) assays have been mostly employed in temperate climates. However, their value as monitoring tools in tropical and subtropical regions is unknown since the geographic and temporal stability of the assays has not been extensively tested. The objective...

Embolia pulmonar séptica de origen cutáneo Septic pulmonary embolism of cutaneous origin

Directory of Open Access Journals (Sweden)

Agustina Sosa Beláustegui

2012-08-01

Full Text Available La embolia pulmonar séptica es una enfermedad grave y poco frecuente que se caracteriza por presentar infiltrados pulmonares bilaterales asociados a un foco infeccioso extrapulmonar. Se relaciona principalmente a endocarditis derecha, tromboflebitis pelviana, accesos vasculares y menos frecuentemente a infecciones profundas como osteomielitis, artritis séptica o piomiositis. El Staphylococcus aureus meticilino-resistente adquirido en la comunidad (SAMR-AC es un patógeno emergente, con alta virulencia y de rápida propagación, que afecta a sujetos sin enfermedades previas relacionadas o factores de riesgo conocidos. Causa infecciones de piel y partes blandas y con menor frecuencia infecciones graves como fascitis necrotizante, artritis séptica, osteomielitis, piomiositis y neumonía necrotizante. Su epidemiología, patogenia y manifestaciones clínicas difieren de las causadas por el SAMR adquirido en el hospital. Presentamos el caso de un varón de 67 años con embolias pulmonares sépticas causadas por SAMR-AC con origen en una infección cutánea.Septic pulmonary embolism is a serious and rare illness characterized by pulmonary infiltrates associated with an extrapulmonary infectious focus. It is mainly related to right-sided endocarditis, pelvic thrombophlebitis, vascular access and less frequently to deep infections such as osteomyelitis, septic arthritis and pyomyositis. The community-acquired methicillin-resistant Staphylococcus aureus (MRSA is an emerging pathogen with high virulence and rapid spread involving subjects without previous related diseases or known risk factors. It causes infections of skin and soft tissue and less frequently other serious infections such as necrotizing fascitits, septic arthritis, osteomyelitis, pyomyositis and necrotizing pneumonia. Epidemiologically, pathogenesis and clinical manifestations differ from those caused by MRSA acquired in the hospital. We present the case of a 67 year-old male with septic

Tropical Cyclone Paka's Initial Explosive Development (10-12 December, 1997)

Science.gov (United States)

Rodgers, Edward B.; Halverson, Jeff; Simpson, Joanne; Olson, William; Pierce, Harold

1999-01-01

Convection associated with an equatorial westerly wind burst was first observed late November during the strong El Nino of 1997 at approximately 2000 km southwest of the Hawaiian Islands. This region of convection lead to the formation of twin tropical cyclones, one in the southern hemisphere named Pam and the other in the northern hemisphere named Paka. During the first week in December, tropical cyclone Paka, the system of concern, reached tropical storm stage as it moved rapidly westward at relatively low latitudes. During the 10-12 of December, Paka rapidly developed into a typhoon.

Averting biodiversity collapse in tropical forest protected areas

OpenAIRE

Laurance, William F; Useche, D. Carolina; Rendeiro, Julio; Kalka, Margareta; Bradshaw, Corey J A; Sloan, Sean P; Laurance, Susan G; Campbell, Mason; Abernethy, Kate; Alvarez, Patricia; Arroyo-Rodriguez, Victor; Ashton, Peter; Benitez-Malvido, Julieta; Blom, Allard; Bobo, Kadiri S

2012-01-01

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon(1-3). With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses(4-9). As pressures mount, it is vital to know whether existing reserves can sustain their bi...

Climate Prediction Center(CPC)Global Tropics Hazards and Benefits Assessment

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Global Tropics Hazards and Benefits Assessment (GTH) is an outlook product for the areas in the Tropics. Forecasts for the Week-1 and Week-2 period are given for...

The potential sensitivity of tropical plants to increased ultraviolet-B radiation

International Nuclear Information System (INIS)

Ziska, L.H.

1996-01-01

Little is known concerning the impact of stratospheric ozone depletion and increasing ultraviolet (UV)-B radiation on the phenology and growth of tropical plants. This is because, ostensibly, tropical plants are already exposed to relatively high levels of UV-B radiation (relative to a temperate environment) and should, therefore, possess a greater degree of tolerance to increased UV-B radiation. In this brief review I hope to show that, potentially, direct and indirect effects on photosynthesis, assimilate partitioning, phenology and biomass could occur in both tropical crops (e.g. cassava, rice) and native species (e.g. Cecropia obtusifolia (Bertol. Fl)., Tetramolopium humile (Gray), Nana sandwicensis L.). However, it should be noted that differences in sensitivity to UV-B radiation can be related to experimental conditions, and care should be taken to ensure that the quantity and quality of background solar radiation remains at near ambient conditions. Nevertheless, by integrating current and past studies on the impact of UV-B radiation on tropical species, I hope to be able to demonstrate that photosynthesis, morphology and growth in tropical plants could be directly affected by UV-B radiation and that UV-B radiation may be a factor in species and community dynamics in natural plant populations in the tropics

On the response of the tropical atmosphere to large-scale deforestation

Science.gov (United States)

Eltahir, E. A. B.; Bras, R. L.

1993-01-01

Recent studies on the Amazon deforestation problem predict that removal of the forest will result in a higher surface temperature, a significant reduction in evaporation and precipitation, and possibly significant changes in the tropical circulation. Here, we discuss the basic mechanisms contributing to the response of the tropical atmosphere to deforestation. A simple linear model of the tropical atmosphere is used in studying the effects of deforestation on climate. It is suggested that the impact of large-scale deforestation on the circulation of the tropical atmosphere consists of two components: the response of the tropical circulation to the negative change in precipitation (heating), and the response of the same circulation to the positive change in surface temperature. Owing to their different signs, the changes in predicted temperature and precipitation excite competing responses working in opposite directions. The predicted change in tropical circulation determines the change, if any, in atmospheric moisture convergence, which is equivalent to the change in run-off. The dependence of run-off predictions on the relative magnitudes of the predicted changes in precipitation and surface temperature implies that the predictions about run-off are highly sensitive, which explains, at least partly, the disagreement between the different models concerning the sign of the predicted change in Amazonian run-off.

Imported tropical neuroinfections: practice skills and knowledge among nurses and nursing students.

Science.gov (United States)

Rajoo, Maheswaari; Sulicova, Andrea; Mroskova, Slavka; Supinova, Maria; Plackova, Anna; Bystra, Martina; Baranova, Lenka; Grezdova, Iveta; Santova, Tatiana; Janakova, Maria; Simova, Zuzana; Cinova, Jana; Cibrikova, Silvia; Decsiova, Zuzana; Lengyelova, Anna; Hlinovska, Jana; Rovna, Silvia; Igazova, Maria; Nadova, Monika; Rakova, Jana; Lehotska, Maria; Moraucikova, Eva; Mizenkova, Ludmila; Novotna, Zuzana; Paukova, Luba; Semjonova, Alexandra; Schlosserova, Alena; Vicanova, Michaela; Balkova, Hilda; Banasova, Vlasta; Horanska, Valeria; Hudakova, Pavlina; Hudakova, Anna; Majernikova, Ludmila; Poliakova, Nikoleta; Suchanova, Renata; Tirpakova, Libusa; Perinova, Nadezda; Vatehova, Drahormira; Komanicky, Dusan; Koudelkova, Vlasta; Capska, Jana; Maskalikova, Tatiana; Hulkova, Vlasta; Treslova, Marie

2013-09-01

Tropical neuroinfections are still cause of substantial mortality in travelers. Therefore, good knowledge of early symptoms is very important for nurses acting as first contact persons. Nurse's practical skills and knowledge of signs and early recognition of tropical neuroinfections, providing first aid and quick action has been studied among graduates of two Tropical Nursing PhD programs (in EU-Countries vs. tropical country) using a standardized questionnaire. Statistical package EPI info was used to determine potential differences between both groups of graduates. Acceptable knowledge on early symptoms and signs of cerebral malaria and meningococcal meningitis in returning travelers was found among 121 graduates of two PhD programs who were included in the study. Of these, 99 questionnaires were filled in Slovakia, Czech Republic and Germany and another 22 were filled in Malaysia, as a part of the Tropical Nursing PhD Study Programs. Nursing students and recent graduates in two PhD programs demonstrated acceptable, although not large-scaled, knowledge of early signs and symptoms of tropical neuroinfections.

The Role of Earthworms in Tropics with Emphasis on Indian Ecosystems

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Radha D. Kale

2010-01-01

Full Text Available The paper highlights the research carried out by different scientists in India on aspects of earthworm population dynamics and species diversity, associated with other soil fauna and microflora. It also deals with the importance of earthworm activity on physicochemical properties of soil with reference to India and other tropical countries. Stress is laid on the earthworm plant association and importance of the secretions of earthworms as plant growth stimulators. Moreover, the earthworm species reported and being utilized for vermicomposting in India are discussed, since vermicomposting is the ultimate technology which renders for the improvement of soil fertility status and plant growth. Earthworms serve as indicators of soil status such as the level of contamination of pollutants: agrochemicals, heavy metals, toxic substances, and industrial effluents; human-induced activities: land-management practices and forest degradation. In all these fields there is lacuna with respect to contributions from India when compared to the available information from other tropical countries. There is lot of scope in the field of research on earthworms to unravel the importance of these major soil macrofauna from holistic ecological studies to the molecular level.

The Role of Earthworms in Tropics with Emphasis on Indian Ecosystems

International Nuclear Information System (INIS)

Kale, R.D.; Karmegam, N.

2010-01-01

The paper highlights the research carried out by different scientists in India on aspects of earthworm population dynamics and species diversity, associated with other soil fauna and microflora. It also deals with the importance of earthworm activity on physicochemical properties of soil with reference to India and other tropical countries. Stress is laid on the earthworm plant association and importance of the secretions of earthworms as plant growth stimulators. Moreover, the earthworm species reported and being utilized for vermicomposting in India are discussed, since vermicomposting is the ultimate technology which renders for the improvement of soil fertility status and plant growth. Earthworms serve as indicators of soil status such as the level of contamination of pollutants: agrochemicals, heavy metals, toxic substances, and industrial effluents; human-induced activities: land-management practices and forest degradation. In all these fields there is lacuna with respect to contributions from India when compared to the available information from other tropical countries. There is lot of scope in the field of research on earthworms to unravel the importance of these major soil macro fauna from holistic ecological studies to the molecular level.

Interannual-to-decadal air-sea interactions in the tropical Atlantic region

Science.gov (United States)

Ruiz-Barradas, Alfredo

2001-09-01

The present research identifies modes of atmosphere-ocean interaction in the tropical Atlantic region and the mechanisms by which air-sea interactions influence the regional climate. Novelties of the present work are (1)the use of relevant ocean and atmosphere variables important to identity coupled variability in the system. (2)The use of new data sets, including realistic diabatic heating. (3)The study of interactions between ocean and atmosphere relevant at interannual-to-decadal time scales. Two tropical modes of variability are identified during the period 1958-1993, the Atlantic Niño mode and the Interhemispheric mode. Those modes have defined structures in both ocean and atmosphere. Anomalous sea surface temperatures and winds are associated to anomalous placement of the Intertropical Convergence Zone (ITCZ). They develop maximum amplitude during boreal summer and spring, respectively. The anomalous positioning of the ITCZ produces anomalous precipitation in some places like Nordeste, Brazil and the Caribbean region. Through the use of a diagnostic primitive equation model, it is found that the most important terms controlling local anomalous surface winds over the ocean are boundary layer temperature gradients and diabatic heating anomalies at low levels (below 780 mb). The latter is of particular importance in the deep tropics in producing the anomalous meridional response to the surface circulation. Simulated latent heat anomalies indicate that a thermodynamic feedback establishes positive feedbacks at both sides of the equator and west of 20°W in the deep tropics and a negative feedback in front of the north west coast of Africa for the Interhemispheric mode. This thermodynamic feedback only establishes negative feedbacks for the Atlantic Niño mode. Transients establish some connection between the tropical Atlantic and other basins. Interhemispheric gradients of surface temperature in the tropical Atlantic influence winds in the midlatitude North

A New Coupled Ocean-Waves-Atmosphere Model Designed for Tropical Storm Studies: Example of Tropical Cyclone Bejisa (2013-2014) in the South-West Indian Ocean

Science.gov (United States)

Pianezze, J.; Barthe, C.; Bielli, S.; Tulet, P.; Jullien, S.; Cambon, G.; Bousquet, O.; Claeys, M.; Cordier, E.

2018-03-01

Ocean-Waves-Atmosphere (OWA) exchanges are not well represented in current Numerical Weather Prediction (NWP) systems, which can lead to large uncertainties in tropical cyclone track and intensity forecasts. In order to explore and better understand the impact of OWA interactions on tropical cyclone modeling, a fully coupled OWA system based on the atmospheric model Meso-NH, the oceanic model CROCO, and the wave model WW3 and called MSWC was designed and applied to the case of tropical cyclone Bejisa (2013-2014). The fully coupled OWA simulation shows good agreement with the literature and available observations. In particular, simulated significant wave height is within 30 cm of measurements made with buoys and altimeters. Short-term (right place (in the eyewall of the tropical cyclone) and with the right size distribution, which is critical for cloud microphysics.

Comprehensive overview of FPL field testing conducted in the tropics (1945-2005)

Science.gov (United States)

Grant T. Kirker; Stan L. Lebow; Mark E. Mankowski

2016-01-01

Tropical exposure often represents a more severe environment for treated wood and wood based products. Accelerated tropical decay rates are typically attributed to higher mean rainfall and temperatures. The Forest Products Laboratory (FPL) in Madison, WI has been conducting tropical field tests in a variety of locations since the early 1940’s. This paper summarizes FPL...

Regional impacts of ocean color on tropical Pacific variability

Science.gov (United States)

Anderson, W.; Gnanadesikan, A.; Wittenberg, A.

2009-08-01

The role of the penetration length scale of shortwave radiation into the surface ocean and its impact on tropical Pacific variability is investigated with a fully coupled ocean, atmosphere, land and ice model. Previous work has shown that removal of all ocean color results in a system that tends strongly towards an El Niño state. Results from a suite of surface chlorophyll perturbation experiments show that the mean state and variability of the tropical Pacific is highly sensitive to the concentration and distribution of ocean chlorophyll. Setting the near-oligotrophic regions to contain optically pure water warms the mean state and suppresses variability in the western tropical Pacific. Doing the same above the shadow zones of the tropical Pacific also warms the mean state but enhances the variability. It is shown that increasing penetration can both deepen the pycnocline (which tends to damp El Niño) while shifting the mean circulation so that the wind response to temperature changes is altered. Depending on what region is involved this change in the wind stress can either strengthen or weaken ENSO variability.

Fungal and Oomycete Diseases of Tropical Tree Fruit Crops.

Science.gov (United States)

Drenth, André; Guest, David I

2016-08-04

The tropics produce a range of fruit from tree crops that cannot be grown in colder climates. Bananas, mangos, several nuts, spices, coffee, and cacao are widely traded and much sought after around the world. However, the sustainable production of these tropical tree fruit crops faces significant challenges. Among these, losses due to pests and diseases play a large part in reducing yields, quality, and profitability. Using bananas and cacao as key examples, we outline some of the reasons fungal and oomycete diseases cause such significant losses to tropical tree crops. Cultivation of monocultures derived from limited genetic diversity, environmental conditions conducive for disease development, high levels of disease incidence and severity, a lack of disease resistance in planting materials, shortages of labor, and inadequate infrastructure and investment pose significant challenges, especially for smallholder producers. The expansion of travel and trade has given rise to emerging infectious plant diseases that add further insecurity and pressure. We conclude that holistic actions are needed on multiple fronts to address the growing problem of disease in tropical fruit tree crops.

Classic Maya civilization collapse associated with reduction in tropical cyclone activity

Science.gov (United States)

Medina, M. A.; Polanco-Martinez, J. M.; Lases-Hernández, F.; Bradley, R. S.; Burns, S. J.

2013-12-01

In light of the increased destructiveness of tropical cyclones observed over recent decades one might assume that an increase and not a decrease in tropical cyclone activity would lead to societal stress and perhaps collapse of ancient cultures. In this study we present evidence that a reduction in the frequency and intensity of tropical Atlantic cyclones could have contributed to the collapse of the Maya civilization during the Terminal Classic Period (TCP, AD. 800-950). Statistical comparisons of a quantitative precipitation record from the Yucatan Peninsula (YP) Maya lowlands, based on the stalagmite known as Chaac (after the Mayan God of rain and agriculture), relative to environmental proxy records of El Niño/Southern Oscillation (ENSO), tropical Atlantic sea surface temperatures (SSTs), and tropical Atlantic cyclone counts, suggest that these records share significant coherent variability during the TCP and that summer rainfall reductions between 30 and 50% in the Maya lowlands occurred in association with decreased Atlantic tropical cyclones. Analysis of modern instrumental hydrological data suggests cyclone rainfall contributions to the YP equivalent to the range of rainfall deficits associated with decreased tropical cyclone activity during the collapse of the Maya civilization. Cyclone driven precipitation variability during the TCP, implies that climate change may have triggered Maya civilization collapse via freshwater scarcity for domestic use without significant detriment to agriculture. Pyramid in Tikal, the most prominent Maya Kingdom that collapsed during the Terminal Classic Period (circa C.E. 800-950) Rainfall feeding stalagmites inside Rio Secreto cave system, Yucatan, Mexico.

Towards a Statistical Model of Tropical Cyclone Genesis

Science.gov (United States)

Fernandez, A.; Kashinath, K.; McAuliffe, J.; Prabhat, M.; Stark, P. B.; Wehner, M. F.

2017-12-01

Tropical Cyclones (TCs) are important extreme weather phenomena that have a strong impact on humans. TC forecasts are largely based on global numerical models that produce TC-like features. Aspects of Tropical Cyclones such as their formation/genesis, evolution, intensification and dissipation over land are important and challenging problems in climate science. This study investigates the environmental conditions associated with Tropical Cyclone Genesis (TCG) by testing how accurately a statistical model can predict TCG in the CAM5.1 climate model. TCG events are defined using TECA software @inproceedings{Prabhat2015teca, title={TECA: Petascale Pattern Recognition for Climate Science}, author={Prabhat and Byna, Surendra and Vishwanath, Venkatram and Dart, Eli and Wehner, Michael and Collins, William D}, booktitle={Computer Analysis of Images and Patterns}, pages={426-436}, year={2015}, organization={Springer}} to extract TC trajectories from CAM5.1. L1-regularized logistic regression (L1LR) is applied to the CAM5.1 output. The predictions have nearly perfect accuracy for data not associated with TC tracks and high accuracy differentiating between high vorticity and low vorticity systems. The model's active variables largely correspond to current hypotheses about important factors for TCG, such as wind field patterns and local pressure minima, and suggests new routes for investigation. Furthermore, our model's predictions of TC activity are competitive with the output of an instantaneous version of Emanuel and Nolan's Genesis Potential Index (GPI) @inproceedings{eman04, title = "Tropical cyclone activity and the global climate system", author = "Kerry Emanuel and Nolan, {David S.}", year = "2004", pages = "240-241", booktitle = "26th Conference on Hurricanes and Tropical Meteorology"}.

Tropical forest policies for the global climate

International Nuclear Information System (INIS)

De Groot, W.T.; Kamminga, E.M.

1995-01-01

A summary is given of the approach and findings of the NRP project 'Local Actors and Global Tree Cover Policies'. The aim of this project was to identify the most effective and efficient options for global climate policies focusing on the tropical forest. Tropical deforestation is a process with very complex and variable causes. In the project's conclusions, therefore, much care has been given to arrive at a coherent image of what really counts most in the myriad of factors, actors, policy levels and policy options. 5 refs

FLORULA URBAN FRAGMENT OF TROPICAL DRY FOREST

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Willington Barranco-Pérez

2016-01-01

Full Text Available The aim of this study was to record the composition of plant species in an urban fragment of tropical dry forest of secondary regeneration (bs-T to generate information that can be used in the planning and management of green spaces in the city of Santa Marta. Transects of 2 x 50 m were established equivalent to 0.1 ha and all species were counted >1.0 cm DBH (Diameter at Breast Height: 1.3m. 100 species of angiosperms were recorded of which 47% have herbaceous habit. The number of species recorded in this study represents 39.6% of the species reported for the hills of Santa Marta and 3.8% for the dry forests of Colombia. It is suggested to isolate this type of secondary formations of any intervention and contemplate the reintroduction of individuals and conservation strategies.

Contribution of Tropical Cyclones to the North Pacific Climatological Rainfall as Observed from Satellites.

Science.gov (United States)

Rodgers, Edward B.; Adler, Robert F.; Pierce, Harold F.

2000-10-01

Tropical cyclone monthly rainfall amounts are estimated from passive microwave satellite observations for an 11-yr period. These satellite-derived rainfall amounts are used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and interannual distribution of the North Pacific Ocean total rainfall during June-November when tropical cyclones are most important.To estimate these tropical cyclone rainfall amounts, mean monthly rain rates are derived from passive microwave satellite observations within 444-km radius of the center of those North Pacific tropical cyclones that reached storm stage and greater. These rain-rate observations are converted to monthly rainfall amounts and then compared with those for nontropical cyclone systems.The main results of this study indicate that 1) tropical cyclones contribute 7% of the rainfall to the entire domain of the North Pacific during the tropical cyclone season and 12%, 3%, and 4% when the study area is limited to, respectively, the western, central, and eastern third of the ocean; 2) the maximum tropical cyclone rainfall is poleward (5°-10° latitude depending on longitude) of the maximum nontropical cyclone rainfall; 3) tropical cyclones contribute a maximum of 30% northeast of the Philippine Islands and 40% off the lower Baja California coast; 4) in the western North Pacific, the tropical cyclone rainfall lags the total rainfall by approximately two months and shows seasonal latitudinal variation following the Intertropical Convergence Zone; and 5) in general, tropical cyclone rainfall is enhanced during the El Niño years by warm SSTs in the eastern North Pacific and by the monsoon trough in the western and central North Pacific.

Controls over foliar N:P ratios in tropical rain forests.

Science.gov (United States)

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

2007-01-01

Correlations between foliar nutrient concentrations and soil nutrient availability have been found in multiple ecosystems. These relationships have led to the use of foliar nutrients as an index of nutrient status and to the prediction of broadscale patterns in ecosystem processes. More recently, a growing interest in ecological stoichiometry has fueled multiple analyses of foliar nitrogen:phosphorus (N:P) ratios within and across ecosystems. These studies have observed that N:P values are generally elevated in tropical forests when compared to higher latitude ecosystems, adding weight to a common belief that tropical forests are generally N rich and P poor. However, while these broad generalizations may have merit, their simplicity masks the enormous environmental heterogeneity that exists within the tropics; such variation includes large ranges in soil fertility and climate, as well as the highest plant species diversity of any biome. Here we present original data on foliar N and P concentrations from 150 mature canopy tree species in Costa Rica and Brazil, and combine those data with a comprehensive new literature synthesis to explore the major sources of variation in foliar N:P values within the tropics. We found no relationship between N:P ratios and either latitude or mean annual precipitation within the tropics alone. There is, however, evidence of seasonal controls; in our Costa Rica sites, foliar N:P values differed by 25% between wet and dry seasons. The N:P ratios do vary with soil P availability and/or soil order, but there is substantial overlap across coarse divisions in soil type, and perhaps the most striking feature of the data set is variation at the species level. Taken as a whole, our results imply that the dominant influence on foliar N:P ratios in the tropics is species variability and that, unlike marine systems and perhaps many other terrestrial biomes, the N:P stoichiometry of tropical forests is not well constrained. Thus any use of N

Coordenadas epistemológicas de la medicina tropical

Directory of Open Access Journals (Sweden)

Caponi Sandra

2003-01-01

Full Text Available Para intentar comprender la novedad, en términos teóricos y epistemológicos, representada por la emergencia de la medicina tropical analizamos aquí dos modelos de investigación representados por los institutos Pasteur de ultramar y The London School of Tropical Medecine. Pretendemos saber qué argumentos y conceptos entran en juego en sus discursos; de qué modo son construidos sus protocolos de investigación; en qué se diferencian y en qué se aproximan estos protocolos, conceptos y argumentos; en fin, si es posible hablar de novedad epistemológica, o de inconmensurabilidad de la medicina tropical en relación a la medicina heredera de Pasteur y a la tradición médica ocupada con las enfermedades de climas tórridos.

Weak simulated extratropical responses to complete tropical deforestation

Science.gov (United States)

Findell, K.L.; Knutson, T.R.; Milly, P.C.D.

2006-01-01

The Geophysical Fluid Dynamics Laboratory atmosphere-land model version 2 (AM2/LM2) coupled to a 50-m-thick slab ocean model has been used to investigate remote responses to tropical deforestation. Magnitudes and significance of differences between a control run and a deforested run are assessed through comparisons of 50-yr time series, accounting for autocorrelation and field significance. Complete conversion of the broadleaf evergreen forests of South America, central Africa, and the islands of Oceania to grasslands leads to highly significant local responses. In addition, a broad but mild warming is seen throughout the tropical troposphere (deforested run and the control run are similar in magnitude and area to the differences between nonoverlapping segments of the control run. These simulations suggest that extratropical responses to complete tropical deforestation are unlikely to be distinguishable from natural climate variability.

Phytochemicals and Medicinal Properties of Indigenous Tropical Fruits with Potential for Commercial Development

Directory of Open Access Journals (Sweden)

Hock Eng Khoo

2016-01-01

Full Text Available Hundreds of fruit-bearing trees are native to Southeast Asia, but many of them are considered as indigenous or underutilized. These species can be categorized as indigenous tropical fruits with potential for commercial development and those possible for commercial development. Many of these fruits are considered as underutilized unless the commercialization is being realized despite the fact that they have the developmental potential. This review discusses seven indigenous tropical fruits from 15 species that have been identified, in which their fruits are having potential for commercial development. As they are not as popular as the commercially available fruits, limited information is found. This paper is the first initiative to provide information on the phytochemicals and potential medicinal uses of these fruits. Phytochemicals detected in these fruits are mainly the phenolic compounds, carotenoids, and other terpenoids. Most of these phytochemicals are potent antioxidants and have corresponded to the free radical scavenging activities and other biological activities of the fruits. The scientific research that covered a broad range of in vitro to in vivo studies on the medicinal potentials of these fruits is also discussed in detail. The current review is an update for researchers to have a better understanding of the species, which simultaneously can provide awareness to enhance their commercial value and promote their utilization for better biodiversity conservation.

Sea level variability in the eastern tropical Pacific as observed by TOPEX and Tropical Ocean-Global Atmosphere Tropical Atmosphere-Ocean Experiment

Science.gov (United States)

Giese, Benjamin S.; Carton, James A.; Holl, Lydia J.

1994-01-01

Sea surface height measurements from the TOPEX altimeter and dynamic height from Tropical Ocean-Global Atmosphere Tropical Atmosphere-Ocean (TOGA TAO) moorings are used to explore sea level variability in the northeastern tropical Pacific Ocean. Afetr the annual harmonic is removed, there are two distinct bands of variability: one band is centered at 5 deg N to 7 deg N and extends from 165 deg W to 110 deg W, and the other band is centered at 10 deg N to 12 deg N and extends from 120 deg W to the coast of Central America. The correspondence between the two independent observation data sets at 5 deg N is excellent with correlations of about 90%. The variability at 5 deg-7 deg N is identified as instability waves formed just south of the North Equatorial Countercurrent during the months of July and March. Wave amplitudes are largest in the range of longitudes 160 deg-140 deg W, where they can exceed 10 cm. The waves disappear when the equatorial current system weakens, during the months of March and May. The variability at 11 deg N in 1993 has the form of anticyclone eddies. These eddies propagate westward at a speed of about 17 cm/s, consistent with the dispersion characteristics of free Rossby waves. The eddies are shown to have their origin near the coast of central America during northern fall and winter. Their formation seems to result from intense wind bursts across the Gulfs of Tehuantepec and Papagayo which generate strong anticyclonic ocean eddies. The disappearance of the eddies in the summer of 1993 coincidences with the seasonal intensification of equatorial currents. Thus the variability at 11 deg N has very little overlap in time with the variability at 5 deg N.

Interannual variability of the tropical Indian Ocean mixed layer depth

Digital Repository Service at National Institute of Oceanography (India)

Keerthi, M.G.; Lengaigne, M.; Vialard, J.; Montegut, C.deB.; Muraleedharan, P.M.

, shoaling the MLD (Masson et al. 2002, Qu and Meyers 2005, Du et al. 2005). The seasonal cycle in the southern tropical Indian Ocean has been less 3 investigated. Seasonal shoaling and deepening of the mixed layer in the south-western Tropical Indian...

Interpretation of TOMS Observations of Tropical Tropospheric Ozone with a Global Model and In Situ Observations

Science.gov (United States)

Martin, Randall V.; Jacob, Daniel J.; Logan, Jennifer A.; Bey, Isabelle; Yantosca, Robert M.; Staudt, Amanda C.; Fiore, Arlene M.; Duncan, Bryan N.; Liu, Hongyu; Ginoux, Paul

2004-01-01

We interpret the distribution of tropical tropospheric ozone columns (TTOCs) from the Total Ozone Mapping Spectrometer (TOMS) by using a global three-dimensional model of tropospheric chemistry (GEOS-CHEM) and additional information from in situ observations. The GEOS-CHEM TTOCs capture 44% of the variance of monthly mean TOMS TTOCs from the convective cloud differential method (CCD) with no global bias. Major discrepancies are found over northern Africa and south Asia where the TOMS TTOCs do not capture the seasonal enhancements from biomass burning found in the model and in aircraft observations. A characteristic feature of these northern topical enhancements, in contrast to southern tropical enhancements, is that they are driven by the lower troposphere where the sensitivity of TOMS is poor due to Rayleigh scattering. We develop an efficiency correction to the TOMS retrieval algorithm that accounts for the variability of ozone in the lower troposphere. This efficiency correction increases TTOC's over biomass burning regions by 3-5 Dobson units (DU) and decreases them by 2-5 DU over oceanic regions, improving the agreement between CCD TTOCs and in situ observations. Applying the correction to CCD TTOCs reduces by approximately DU the magnitude of the "tropical Atlantic paradox" [Thompson et al, 2000], i.e. the presence of a TTOC enhancement over the southern tropical Atlantic during the northern African biomass burning season in December-February. We reproduce the remainder of the paradox in the model and explain it by the combination of upper tropospheric ozone production from lightning NOx, peristent subsidence over the southern tropical Atlantic as part of the Walker circulation, and cross-equatorial transport of upper tropospheric ozone from northern midlatitudes in the African "westerly duct." These processes in the model can also account for the observed 13-17 DU persistent wave-1 pattern in TTOCs with a maximum above the tropical Atlantic and a minimum

Multi-Scale Aspects of Tropical Cyclone Predictability

Science.gov (United States)

Doyle, J. D.; Moskaitis, J.; Black, P. G.; Hendricks, E. A.; Reinecke, A.; Amerault, C. M.

2014-12-01

The intensification of tropical cyclones (TCs) may be sensitive to aspects of large-scale forcing, as well as internal mesoscale dynamics. In this presentation, the degree to which tropical cyclone intensity and structure is sensitive to small perturbations to the basic properties of the synoptic-scale environment, as well as in the immediate vicinity of the storm, is explored using both adjoint- and ensemble-based approaches. In particular, we explore the relationship between tropical cyclone intensity changes and upper-level outflow. We make use of observations from two recent field campaigns: i) the NASA Hurricane and Severe Storms Sentinel (HS3), which featured two fully instrumented Global Hawk unmanned aerial systems, and ii) the ONR Tropical Cyclone Intensity (TCI-14) experiment that utilized the NASA WB-57. We make use of the Navy's high-resolution tropical cyclone prediction system COAMPS-TC to provide ensemble forecasts, numerical experiments with and without the assimilation of specific observation types (e.g., satellite, dropsondes, high-frequency radiosonde), as well as mesoscale nested adjoint sensitivity and observation impact calculations, all of which provide insight into the initial state sensitivity and predictability issues. We assess the impact of observations in sensitive regions in the TC environment (including outflow regions away from the TC inner core) on predictions of TC intensity and structure. Overall the results underscore the importance of multiple scales that influence the predictability of TC intensification. During HS3, the assimilation of Global Hawk dropsondes has been shown to reduce the maximum wind error from 15 knots to less than 10 knots at 48 h for Hurricane Nadine (2012). In this particular case, the adjoint model shows strong sensitivity in the TC outflow near the entrance region of an upper-level jet. The impact of dropsondes from data denial experiments and adjoint-based observation impact calculations will be

Response of tropical peat swamp forest tree species seedlings to macro nutrients

Directory of Open Access Journals (Sweden)

Tri Wira Yuwati

2015-10-01

Full Text Available Abstract Efforts of restoration of degraded tropical peat swamp forest were facing constraints due to the low available nutrient level of peat. The transplanted peat swamp forest species seedlings experienced low survival rate and poor growth performance. This study aimed to demonstrate the response of ten tropical peat swamp forest species seedlings whether climax and pioneer species to macro-nutrients addition in the nursery. The growth performance of climax and pioneer tropical peat swamp species seedlings was recorded following addition of macro nutrients of Nitrogen (N, Phosphorus(P, Potassium(K and Dolomitic limestone (CaMg. The result showed that Alstonia spatulata and Parartocarpus venenosus showed positive growth response following macro nutrients addition. This study concluded that tropical peat swamp pioneer species has lower necessity for macro-nutrients addition than tropical peat swamp climax species.

Cutover tropical forest productivity potential merits assessment, Puerto Rico

Science.gov (United States)

Frank H. Wadsworth; Brynne Bryan; Julio Figueroa-Colón

2010-01-01

Timber extraction continues to add to vast cutover tropical forests. They are unattractive economically because of the loss of merchantable timber and the long delay foreseen for recovery. Despite this, wood in cutover tropical forests is in line to become more marketable as demand continues and old-growth forests become less accessible. In a cutover forest in Puerto...

Orbital Forcing driving climate variability on Tropical South Atlantic

Science.gov (United States)

Oliveira, A. S.; Baker, P. A.; Silva, C. G.; Dwyer, G. S.; Chiessi, C. M.; Rigsby, C. A.; Ferreira, F.

2017-12-01

Past research on climate response to orbital forcing in tropical South America has emphasized on high precession cycles influencing low latitude hydrologic cycles, and driving the meridional migration of Intertropical Convergence Zone (ITCZ).However, marine proxy records from the tropical Pacific Ocean showed a strong 41-ka periodicities in Pleistocene seawater temperature and productivity related to fluctuations in Earth's obliquity. It Indicates that the western Pacific ITCZ migration was influenced by combined precession and obliquity changes. To reconstruct different climate regimes over the continent and understand the orbital cycle forcing over Tropical South America climate, hydrological reconstruction have been undertaken on sediment cores located on the Brazilian continental slope, representing the past 1.6 million years. Core CDH 79 site is located on a 2345 m deep seamount on the northern Brazilian continental slope (00° 39.6853' N, 44° 20.7723' W), 320 km from modern coastline of the Maranhão Gulf. High-resolution XRF analyses of Fe, Ti, K and Ca are used to define the changes in precipitation and sedimentary input history of Tropical South America. The response of the hydrology cycle to orbital forcing was studied using spectral analysis.The 1600 ka records of dry/wet conditions presented here indicates that orbital time-scale climate change has been a dominant feature of tropical climate. We conclude that the observed oscillation reflects variability in the ITCZ activity associated with the Earth's tilt. The prevalence of the eccentricity and obliquity signals in continental hydrology proxies (Ti/Ca and Fe/K) as implicated in our precipitation records, highlights that these orbital forcings play an important role in tropics hydrologic cycles. Throughout the Quaternary abrupt shifts of tropical variability are temporally correlated with abrupt climate changes and atmospheric reorganization during Mid-Pleistocene Transition and Mid-Brunhes Events

CMS: Estimated Deforested Area Biomass, Tropical America, Africa, and Asia, 2000

Data.gov (United States)

National Aeronautics and Space Administration — This data set provides estimates of pre-deforestation aboveground live woody biomass (AGLB) at 30-m resolution for deforested areas of tropical America, tropical...

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.

Tropic Testing of Vehicles

Science.gov (United States)

2014-08-27

kilometer track running through tropical forest. The track is a combination of a bauxite /dirt base with grades on the road up to 20 percent and log...bridges crossing 11 creeks. The track site is located in a private concession used mainly for gold mining ; however, logging operations are active in the

Which statistics should tropical biologists learn?

Directory of Open Access Journals (Sweden)

Natalia Loaiza Velásquez

2011-09-01

Full Text Available Tropical biologists study the richest and most endangered biodiversity in the planet, and in these times of climate change and mega-extinctions, the need for efficient, good quality research is more pressing than in the past. However, the statistical component in research published by tropical authors sometimes suffers from poor quality in data collection; mediocre or bad experimental design and a rigid and outdated view of data analysis. To suggest improvements in their statistical education, we listed all the statistical tests and other quantitative analyses used in two leading tropical journals, the Revista de Biología Tropical and Biotropica, during a year. The 12 most frequent tests in the articles were: Analysis of Variance (ANOVA, Chi-Square Test, Student’s T Test, Linear Regression, Pearson’s Correlation Coefficient, Mann-Whitney U Test, Kruskal-Wallis Test, Shannon’s Diversity Index, Tukey’s Test, Cluster Analysis, Spearman’s Rank Correlation Test and Principal Component Analysis. We conclude that statistical education for tropical biologists must abandon the old syllabus based on the mathematical side of statistics and concentrate on the correct selection of these and other procedures and tests, on their biological interpretation and on the use of reliable and friendly freeware. We think that their time will be better spent understanding and protecting tropical ecosystems than trying to learn the mathematical foundations of statistics: in most cases, a well designed one-semester course should be enough for their basic requirements. Rev. Biol. Trop. 59 (3: 983-992. Epub 2011 September 01.Los biólogos tropicales estudian la biodiversidad más rica y amenazada del planeta, y en estos tiempos de cambio climático y mega-extinción, la necesidad de investigación de buena calidad es más acuciante que en el pasado. Sin embargo, el componente estadístico en la investigación publicada por los autores tropicales adolece a veces

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

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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.

Tropical Journal of Pharmaceutical Research

African Journals Online (AJOL)

Tropical Journal of Pharmaceutical Research. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 12, No 6 (2013) >. Log in or Register to get access to full text downloads.

Home range use and movement patterns of non-native feral goats in a tropical island montane dry landscape

Science.gov (United States)

Mark W. Chynoweth; Christopher A. Lepczyk; Creighton M. Litton; Steven C. Hess; James R. Kellner; Susan Cordell; Lalit Kumar

2015-01-01

Advances in wildlife telemetry and remote sensing technology facilitate studies of broad-scale movements of ungulates in relation to phenological shifts in vegetation. In tropical island dry landscapes, home range use and movements of non-native feral goats (Capra hircus) are largely unknown, yet this information is important to help guide the...

Role of tropical Indian and Atlantic Oceans variability on ENSO

Science.gov (United States)

Prodhomme, Chloé; Terray, Pascal; Masson, Sebastien; Boschat, Ghyslaine

2014-05-01

There are strong evidences of an interaction between tropical Indian, Atlantic and Pacific Oceans. Nevertheless, these interactions remain deeply controversial. While some authors claim the tropical Indian and Atlantic oceans only play a passive role with respect to ENSO, others suggest a driving role for these two basins on ENSO. The mecanisms underlying these relations are not fully understood and, in the Indian Ocean, the possible role of both modes of tropical variability (the Indian Ocean Dipole (IOD) and the Indian Ocean Basin mode (IOB)) remain unclear. To better quantify and understand how the variability of the tropical Indian and Atlantic Oceans impact ENSO variability, we performed two sensitivity experiments using the SINTEX-F2 coupled model. For each experiment, we suppressed the variability of SST and the air-sea coupling in either the tropical Indian Ocean or tropical Atlantic Ocean by applying a strong nudging of the SST to the observed SST climatology. In both experiments, the ENSO periodicity increases. In the Atlantic experiment, our understanding of this increased periodicity is drastically limited by the strongly biased mean state in this region. Conversely, in the Indian Ocean experiment, the increase of ENSO periodicity is related to the absence of the IOB following the El Niño peak, which leads to a decrease of westerly winds in the western Pacific during late winter and spring after the peak. These weaker westerlies hinders the transition to a La Niña phase and thus increase the duration and periodicity of the event.

Sustainable Ecosystem Services Framework for Tropical Catchment Management: A Review

Directory of Open Access Journals (Sweden)

N. Zafirah

2017-04-01

Full Text Available The monsoon season is a natural phenomenon that occurs over the Asian continent, bringing extra precipitation which causes significant impact on most tropical watersheds. The tropical region’s countries are rich with natural rainforests and the economies of the countries situated within the region are mainly driven by the agricultural industry. In order to fulfill the agricultural demand, land clearing has worsened the situation by degrading the land surface areas. Rampant land use activities have led to land degradation and soil erosion, resulting in implications on water quality and sedimentation of the river networks. This affects the ecosystem services, especially the hydrological cycles. Intensification of the sedimentation process has resulted in shallower river systems, thus increasing their vulnerability to natural hazards (i.e., climate change, floods. Tropical forests which are essential in servicing their benefits have been depleted due to the increase in human exploitation. This paper provides an overview of the impact of land erosion caused by land use activities within tropical rainforest catchments, which lead to massive sedimentation in tropical rivers, as well as the effects of monsoon on fragile watersheds which can result in catastrophic floods. Forest ecosystems are very important in giving services to regional biogeochemical processes. Balanced ecosystems therefore, play a significant role in servicing humanity and ultimately, may create a new way of environmental management in a cost-effective manner. Essentially, such an understanding will help stakeholders to come up with better strategies in restoring the ecosystem services of tropical watersheds.

Spatial Distributions of Tropical Cyclone Tornadoes by Intensity and Size Characteristics

OpenAIRE

Todd W. Moore; Nicholas J. Sokol; Robert A. Blume

2017-01-01

Tropical cyclones that make landfall often spawn tornadoes. Previous studies have shown that these tornadoes are not uniformly distributed in the United States or in the tropical cyclone environment. They show that tornadoes tend to occur relatively close to the coastline and that they tend to cluster to the east-of-center in the tropical cyclone environment, particularly in the northeast and east-of-center quadrants. This study contributes to these studies by analyzing the spatial distributi...

No evidence that elevated CO2 gives tropical lianas an advantage over tropical trees.

Science.gov (United States)

Marvin, David C; Winter, Klaus; Burnham, Robyn J; Schnitzer, Stefan A

2015-05-01

Recent studies indicate that lianas are increasing in size and abundance relative to trees in neotropical forests. As a result, forest dynamics and carbon balance may be altered through liana-induced suppression of tree growth and increases in tree mortality. Increasing atmospheric CO2 is hypothesized to be responsible for the increase in neotropical lianas, yet no study has directly compared the relative response of tropical lianas and trees to elevated CO2 . We explicitly tested whether tropical lianas had a larger response to elevated CO2 than co-occurring tropical trees and whether seasonal drought alters the response of either growth form. In two experiments conducted in central Panama, one spanning both wet and dry seasons and one restricted to the dry season, we grew liana (n = 12) and tree (n = 10) species in open-top growth chambers maintained at ambient or twice-ambient CO2 levels. Seedlings of eight individuals (four lianas, four trees) were grown in the ground in each chamber for at least 3 months during each season. We found that both liana and tree seedlings had a significant and positive response to elevated CO2 (in biomass, leaf area, leaf mass per area, and photosynthesis), but that the relative response to elevated CO2 for all variables was not significantly greater for lianas than trees regardless of the season. The lack of differences in the relative response between growth forms does not support the hypothesis that elevated CO2 is responsible for increasing liana size and abundance across the neotropics. © 2014 John Wiley & Sons Ltd.

Ice Nucleation and Dehydration in the Tropical Tropopause Layer

Science.gov (United States)

Jensen, Eric J.; Diskin, Glenn S.; Lawson, R Paul; Lance, Sara; Bui, Thaopaul Van; Hlavka, Dennis L.; Mcgill, Matthew J.; Pfister, Leonhard; Toon, Owen B.; Gao, Rushan

2013-01-01

Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth's radiation budget and climate. Recent highaltitude, unmanned aircraft measurements provide evidence for two distinct classes of cirrus formed in the tropical tropopause region: (i) vertically extensive cirrus with low ice number concentrations, low extinctions, and large supersaturations (up to approx. 70%) with respect to ice; and (ii) vertically thin cirrus layers with much higher ice concentrations that effectively deplete the vapor in excess of saturation. The persistent supersaturation in the former class of cirrus is consistent with the long time-scales (several hours or longer) for quenching of vapor in excess of saturation given the low ice concentrations and cold tropical tropopause temperatures. The low-concentration clouds are likely formed on a background population of insoluble particles with concentrations less than 100 L-1 (often less than 20 L-1), whereas the high ice concentration layers (with concentrations up to 10,000 L-1) can only be produced by homogeneous freezing of an abundant population of aqueous aerosols. These measurements, along with past high-altitude aircraft measurements, indicate that the low-concentration cirrus occur frequently in the tropical tropopause region, whereas the high-concentration cirrus occur infrequently. The predominance of the low-concentration clouds means cirrus near the tropical tropopause may typically allow entry of air into the stratosphere with as much as approx. 1.7 times the ice saturation mixing ratio.

Knowledge exchange in the Pacific: The TROPIC (Translational Research into Obesity Prevention Policies for Communities) project

Science.gov (United States)

2012-01-01

Background Policies targeting obesogenic environments and behaviours are critical to counter rising obesity rates and lifestyle-related non-communicable diseases (NCDs). Policies are likely to be most effective and enduring when they are based on the best available evidence. Evidence-informed policy making is especially challenging in countries with limited resources. The Pacific TROPIC (Translational Research for Obesity Prevention in Communities) project aims to implement and evaluate a tailored knowledge-brokering approach to evidence-informed policy making to address obesity in Fiji, a Pacific nation challenged by increasingly high rates of obesity and concomitant NCDs. Methods The TROPIC project draws on the concept of ‘knowledge exchange’ between policy developers (individuals; organisations) and researchers to deliver a knowledge broking programme that maps policy environments, conducts workshops on evidence-informed policy making, supports the development of evidence-informed policy briefs, and embeds evidence-informed policy making into organisational culture. Recruitment of government and nongovernment organisational representatives will be based on potential to: develop policies relevant to obesity, reach broad audiences, and commit to resourcing staff and building a culture that supports evidence-informed policy development. Workshops will increase awareness of both obesity and policy cycles, as well as develop participants’ skills in accessing, assessing and applying relevant evidence to policy briefs. The knowledge-broking team will then support participants to: 1) develop evidence-informed policy briefs that are both commensurate with national and organisational plans and also informed by evidence from the Pacific Obesity Prevention in Communities project and elsewhere; and 2) collaborate with participating organisations to embed evidence-informed policy making structures and processes. This knowledge broking initiative will be evaluated via

Cycad diversification and tropical biodiversity

Directory of Open Access Journals (Sweden)

Rull, V.

2012-12-01

Full Text Available The recent unexpected discovery that living Cycadales are not Jurassic-Cretaceous (200– 65 Mya relicts, as all their extant genera began to diversify during the Late Miocene (12 Mya, has challenged a classical evolutionary myth. This brief note shows how this finding may also provide new clues on the shaping of the high tropical biodiversity

El reciente e inesperado descubrimiento de que las Cycadales actuales no son relictos Jurásico-Cretácicos (200-65 Mya, ya que todos sus géneros iniciaron su diversificación durante el Mioceno Tardío (12 Mya, ha puesto en entredicho un mito evolutivo clásico. En esta nota se expone como este hallazgo puede, además, proporcionar nuevas pistas sobre el origen de la elevada biodiversidad tropical.

Tropical Wetlands as Carbon Sinks

Science.gov (United States)

Jones, M. B.; Saunders, M.

2007-12-01

This presentation focuses on the tropical wetlands of sub-Saharan Africa. These are an understudied ecosystem in which large emergent grasses and sedges normally dominate and which have the potential to sequester significant amounts of carbon. Measurements of Net Primary Production of these wetlands show that they are some of the highest values recorded for any ecosystem. We have used eddy covariance to measure Net Ecosystem Exchange of pristine and disturbed wetlands and show that pristine systems can have sink strengths as strong as tropical forests while disturbed systems that have been reclaimed for agricultural purposes have a very much reduced carbon sink activity and may be net carbon sources. The management issues surrounding the use of these wetlands illustrate a direct conflict between the production of food crops for the local population and the maintenance of carbon sequestration as an ecosystem service.

Biogas energy production from tropical biomass wastes by anaerobic digestion

Science.gov (United States)

Anaerobic digestion (AD) is an attractive technology in tropical regions for converting locally abundant biomass wastes into biogas which can be used to produce heat, electricity, and transportation fuels. However, investigations on AD of tropical forestry wastes, such as albizia biomass, and food w...

Damage-controlled logging in managed tropical rain forest in Suriname

NARCIS (Netherlands)

Hendrison, J.

1990-01-01

Concern about worldwide deforestation and exploitation of the tropical rain forests has led to friction between national governments, wood industries and timber trade on the one hand, and scientists and environmental organizations on the other. One way to safeguard the tropical rain forests

Modelling deep convection and its impacts on the tropical tropopause layer

Directory of Open Access Journals (Sweden)

J. S. Hosking

2010-11-01

Full Text Available The UK Met Office's Unified Model is used at a climate resolution (N216, ~0.83°×~0.56°, ~60 km to assess the impact of deep tropical convection on the structure of the tropical tropopause layer (TTL. We focus on the potential for rapid transport of short-lived ozone depleting species to the stratosphere by rapid convective uplift. The modelled horizontal structure of organised convection is shown to match closely with signatures found in the OLR satellite data. In the model, deep convective elevators rapidly lift air from 4–5 km up to 12–14 km. The influx of tropospheric air entering the TTL (11–12 km is similar for all tropical regions with most convection stopping below ~14 km. The tropical tropopause is coldest and driest between November and February, coinciding with the greatest upwelling over the tropical warm pool. As this deep convection is co-located with bromine-rich biogenic coastal emissions, this period and location could potentially be the preferential gateway for stratospheric bromine.

CATIE: Tropical Agricultural Research and Higher Education Center. http://www.catie.ac.cr

Science.gov (United States)

Applied Environmental Education and Communication, 2004

2004-01-01

This article features CATIE (Centro Agronomico Tropical de Investigacion y Ensenanza), a tropical agricultural research and higher education center. CATIE's mission is to be instrumental in poverty reduction and rural development in the American tropics, by promoting diversified and competitive agriculture and sustainable management of natural…

Tropical Journal of Health Sciences

African Journals Online (AJOL)

The Tropical Journal of Health Sciences (TJHS) is an international journal which ... of ideas to those engaged in work in the Health Sciences and related fields. The journal intends to publish high quality papers on original research, case ...

Temperature variability over the tropical middle atmosphere

Directory of Open Access Journals (Sweden)

K. Mohanakumar

1994-04-01

Full Text Available A study on the variability of temperature in the tropical middle atmosphere over Thumba (8 32' N, 76 52' E, located at the southern part of India, has been carried out based on rocket observations for a period of 20 years, extending from 1970 to 1990. The rocketsonde-derived mean temperatures over Thumba are corrected prior to 1978 and then compared with the middle atmospheric reference model developed from satellite observations and Solar Mesosphere Explorer (SME satellite data. Temperature variability at every 1 km interval in the 25-75 km region was analysed. The tropical stratosphere is found to be highly stable, whereas considerable variability is noted in the middle mesosphere. The effect of seasonal cycle is least in the lower stratosphere. Annual and semi-annual oscillations in temperature are the primary oscillations in the tropical middle atmosphere. Annual temperature oscillations are dominant in the mesosphere and semi-annual oscillations are strong in the stratosphere. The stratopause region is noted to be the part of the middle atmosphere least sensitive to the changes in solar activity and long-term variability.

Application of the Marsupial Paradigm to Tropical Cyclone Formation from Northwestward-Propagating Disturbances

Science.gov (United States)

Wang, Zhuo; Dunkerton, Timothy J.; Montgomery, Michael T.

2012-01-01

A wave-tracking algorithm is developed for northwestward-propagating waves that, on occasion, play a role in tropical cyclogenesis over the western oceans. To obtain the Lagrangian flow structure, the frame of reference is translated obliquely at the same propagation speed with the precursor disturbance. Trajectory analysis suggests that streamlines in the obliquely translated frame of reference can be used to approximate flow trajectories. The algorithm was applied to Super Typhoon Nakri (2008), Tropical Cyclone Erika (2009), and a few other examples. Diagnoses of meteorological analyses and satellite-derived moisture and precipitation fields show that the marsupial framework for tropical cyclogenesis in tropical easterly waves is relevant also for northwestward-propagating disturbances as are commonly observed in the tropical western Atlantic, the Gulf of Mexico, and the western North Pacific. Finally, it is suggested that analysis of the global model data and satellite observations in the marsupial framework can provide useful guidance on early tropical cyclone advisories.

Large scale atmospheric tropical circulation changes and consequences during global warming

International Nuclear Information System (INIS)

Gastineau, G.

2008-01-01

The changes of the tropical large scale circulation during climate change can have large impacts on human activities. In a first part, the meridional atmospheric tropical circulation was studied in the different coupled models. During climate change, we find, on the one hand, that the Hadley meridional circulation and the subtropical jet are significantly shifted poleward, and on the other hand, that the intensity of the tropical circulation weakens. The slow down of the atmospheric circulation results from the dry static stability changes affecting the tropical troposphere. Secondly, idealized simulations are used to explain the tropical circulation changes. Ensemble simulation using the model LMDZ4 are set up to study the results from the coupled model IPSLCM4. The weakening of the large scale tropical circulation and the poleward shift of the Hadley cells are explained by both the uniform change and the meridional gradient change of the sea surface temperature. Then, we used the atmospheric model LMDZ4 in an aqua-planet configuration. The Hadley circulation changes are explained in a simple framework by the required poleward energy transport. In a last part, we focus on the water vapor distribution and feedback in the climate models. The Hadley circulation changes were shown to have a significant impact on the water vapour feedback during climate change. (author)

Spatial patterns and recent trends in the climate of tropical rainforest regions.

Science.gov (United States)

Malhi, Yadvinder; Wright, James

2004-03-29

We present an analysis of the mean climate and climatic trends of tropical rainforest regions over the period 1960-1998, with the aid of explicit maps of forest cover and climatological databases. Until the mid-1970s most regions showed little trend in temperature, and the western Amazon experienced a net cooling probably associated with an interdecadal oscillation. Since the mid-1970s, all tropical rainforest regions have experienced a strong warming at a mean rate of 0.26 +/- 0.05 degrees C per decade, in synchrony with a global rise in temperature that has been attributed to the anthropogenic greenhouse effect. Over the study period, precipitation appears to have declined in tropical rainforest regions at a rate of 1.0 +/- 0.8% per decade (p Africa (at 3-4% per decade), declining marginally in tropical Asia and showing no significant trend in Amazonia. There is no evidence so far of a decline in precipitation in eastern Amazonia, a region thought vulnerable to climate-change-induced drying. The strong drying trend in Africa suggests that this should be a priority study region for understanding the impact of drought on tropical rainforests. We develop and use a dry-season index to study variations in the length and intensity of the dry season. Only African and Indian tropical rainforests appear to have seen a significant increase in dry-season intensity. In terms of interannual variability, the El Niño-Southern Oscillation (ENSO) is the primary driver of temperature variations across the tropics and of precipitation fluctuations for large areas of the Americas and southeast Asia. The relation between ENSO and tropical African precipitation appears less direct.

Can carbon emissions from tropical deforestation drop by 50% in 5 years?

Science.gov (United States)

Zarin, Daniel J; Harris, Nancy L; Baccini, Alessandro; Aksenov, Dmitry; Hansen, Matthew C; Azevedo-Ramos, Claudia; Azevedo, Tasso; Margono, Belinda A; Alencar, Ane C; Gabris, Chris; Allegretti, Adrienne; Potapov, Peter; Farina, Mary; Walker, Wayne S; Shevade, Varada S; Loboda, Tatiana V; Turubanova, Svetlana; Tyukavina, Alexandra

2016-04-01

Halving carbon emissions from tropical deforestation by 2020 could help bring the international community closer to the agreed goal of deforestation at 2.270 Gt CO2 yr(-1). Brazil did not sign the NYDF, yet from 2001 to 2013, Brazil ranks first for both carbon emissions from gross tropical deforestation and reductions in those emissions - its share of the total declined from a peak of 69% in 2003 to a low of 20% in 2012. Indonesia, an NYDF signatory, is the second highest emitter, peaking in 2012 at 0.362 Gt CO2 yr(-1) before declining to 0.205 Gt CO2 yr(-1) in 2013. The other 14 NYDF tropical country signatories were responsible for a combined average of 0.317 Gt CO2 yr(-1) , while the other 86 tropical country non-signatories were responsible for a combined average of 0.688 Gt CO2 yr(-1). We outline two scenarios for achieving the 50% emission reduction target by 2020, both emphasizing the critical role of Brazil and the need to reverse the trends of increasing carbon emissions from gross tropical deforestation in many other tropical countries that, from 2001 to 2013, have largely offset Brazil's reductions. Achieving the target will therefore be challenging, even though it is in the self-interest of the international community. Conserving rather than cutting down tropical forests requires shifting economic development away from a dependence on natural resource depletion toward recognition of the dependence of human societies on the natural capital that tropical forests represent and the goods and services they provide. © 2015 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

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.

Extinction risks forced by climatic change and intraspecific variation in the thermal physiology of a tropical lizard.

Science.gov (United States)

Pontes-da-Silva, Emerson; Magnusson, William E; Sinervo, Barry; Caetano, Gabriel H; Miles, Donald B; Colli, Guarino R; Diele-Viegas, Luisa M; Fenker, Jessica; Santos, Juan C; Werneck, Fernanda P

2018-04-01

Temperature increases can impact biodiversity and predicting their effects is one of the main challenges facing global climate-change research. Ectotherms are sensitive to temperature change and, although predictions indicate that tropical species are highly vulnerable to global warming, they remain one of the least studied groups with respect to the extent of physiological variation and local extinction risks. We model the extinction risks for a tropical heliothermic teiid lizard (Kentropyx calcarata) integrating previously obtained information on intraspecific phylogeographic structure, eco-physiological traits and contemporary species distributions in the Amazon rainforest and its ecotone to the Cerrado savannah. We also investigated how thermal-biology traits vary throughout the species' geographic range and the consequences of such variation for lineage vulnerability. We show substantial variation in thermal tolerance of individuals among thermally distinct sites. Thermal critical limits were highly correlated with operative environmental temperatures. Our physiological/climatic model predicted relative extinction risks for local populations within clades of K. calcarata for 2050 ranging between 26.1% and 70.8%, while for 2070, extinction risks ranged from 52.8% to 92.8%. Our results support the hypothesis that tropical-lizard taxa are at high risk of local extinction caused by increasing temperatures. However, the thermo-physiological differences found across the species' distribution suggest that local adaptation may allow persistence of this tropical ectotherm in global warming scenarios. These results will serve as basis to further research to investigate the strength of local adaptation to climate change. Persistence of Kentropyx calcarata also depends on forest preservation, but the Amazon rainforest is currently under high deforestation rates. We argue that higher conservation priority is necessary so the Amazon rainforest can fulfill its capacity to

Tropical Journal of Pharmaceutical Research

African Journals Online (AJOL)

Journal Homepage Image. We seek to encourage pharmaceutical and allied research of tropical and international relevance and to foster multidisciplinary research and collaboration among scientists, the pharmaceutical industry and the healthcare professionals. We publish articles in pharmaceutical sciences and related ...

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 ...

Pilot-Plant for Energy Recovery from Tropical Waste Food Materials ...

African Journals Online (AJOL)

An experimental unit for obtaining gaseous methane from waste food materials is discussed and results are presented for experimental tests with animal wastes and tropical waste food materials. The tropical waste food considered include garri, boiled beans and plantains. As expected, the animal wastes produced higher ...

Tropical tele-connections to the Mediterranean climate and weather

Directory of Open Access Journals (Sweden)

P. Alpert

2005-01-01

Full Text Available Some strong natural fluctuations of climate in the Eastern Mediterranean (EM region are shown to be connected to the major tropical systems. Potential relations between EM rainfall extremes to tropical systems, e.g. El Niño, Indian Monsoon and hurricanes, are demonstrated. For a specific event, high resolution modelling of the severe flood on 3-5 December 2001 in Israel suggests a relation to hurricane Olga. In order to understand the factors governing the EM climate variability in the summer season, the relationship between extreme summer temperatures and the Indian Monsoon was examined. Other tropical factors like the Red-Sea Trough system and the Saharan dust are also likely to contribute to the EM climate variability.

Importance of adaptation and genotype × environment interactions in tropical beef breeding systems.

Science.gov (United States)

Burrow, H M

2012-05-01

This paper examines the relative importance of productive and adaptive traits in beef breeding systems based on Bos taurus and tropically adapted breeds across temperate and (sub)tropical environments. In the (sub)tropics, differences that exist between breeds in temperate environments are masked by the effects of environmental stressors. Hence in tropical environments, breeds are best categorised into breed types to compare their performance across environments. Because of the presence of environmental stressors, there are more sources of genetic variation in tropical breeding programmes. It is therefore necessary to examine the genetic basis of productive and adaptive traits for breeding programmes in those environments. This paper reviews the heritabilities and genetic relationships between economically important productive and adaptive traits relevant to (sub)tropical breeding programmes. It is concluded that it is possible to simultaneously genetically improve productive and adaptive traits in tropically adapted breeds of beef cattle grazed in tropical environments without serious detrimental consequences for either adaptation or production. However, breed-specific parameters are required for genetic evaluations. The paper also reviews the magnitude of genotype × environment (G × E) interactions impacting on production and adaptation of cattle, where 'genotype' is defined as breed (within a crossbreeding system), sire within breed (in a within-breed selection programme) or associations between economically important traits and single nucleotide polymorphisms (SNPs - within a marker-assisted selection programme). It is concluded that re-ranking of breeds across environments is best managed by the use of the breed type(s) best suited to the particular production environment. Re-ranking of sires across environments is apparent in poorly adapted breed types across extreme tropical and temperate environments or where breeding animals are selected in a temperate

Clutch size declines with elevation in tropical birds

Science.gov (United States)

Boyce, A.J.; Freeman, Benjamin G.; Mitchell, Adam E.; Martin, Thomas E.

2015-01-01

Clutch size commonly decreases with increasing elevation among temperate-zone and subtropical songbird species. Tropical songbirds typically lay small clutches, thus the ability to evolve even smaller clutch sizes at higher elevations is unclear and untested. We conducted a comparative phylogenetic analysis using data gathered from the literature to test whether clutch size varied with elevation among forest passerines from three tropical biogeographic regions—the Venezuelan Andes and adjacent lowlands, Malaysian Borneo, and New Guinea. We found a significant negative effect of elevation on variation in clutch size among species. We found the same pattern using field data sampled across elevational gradients in Venezuela and Malaysian Borneo. Field data were not available for New Guinea. Both sets of results demonstrate that tropical montane species across disparate biogeographic realms lay smaller clutches than closely related low-elevation species. The environmental sources of selection underlying this pattern remain uncertain and merit further investigation.

Mutualism, hybrid inviability and speciation in a tropical ant-plant.

Science.gov (United States)

Léotard, G; Saltmarsh, A; Kjellberg, F; McKey, D

2008-07-01

Although biotic interactions are particularly intricate in the tropics, few studies have examined whether divergent adaptations to biotic interactions lead to speciation in tropical organisms. Ant-plant mutualisms are widespread in the tropics. Within Leonardoxa africana, two subspecies present contrasting defences against herbivores. Young leaves of subsp. africana are defended by mutualistic ants, whereas subsp. gracilicaulis satiates herbivores by synchronized leaf production. Subsp. africana possesses hollow internodes and many large foliar nectaries, housing and feeding ants. We detected no genetic introgression between the two subspecies in the contact zone between them. F1 hybrids were present. They were intermediate in phenotype, expressing reduced, nonfunctional but costly myrmecophilic traits. However, they suffered more herbivory than their parents. Hybrids remained small, failing to reach reproductive size, probably due to their maladapted defence phenotype. Hence, there could be a direct link between adaptation to mutualism and reproductive isolation: biotic interactions could be a driver of tropical diversity.

Frequency and distribution of forest, savanna, and crop fires over tropical regions during PEM-Tropics A

Science.gov (United States)

Olson, Jennifer R.; Baum, Bryan A.; Cahoon, Donald R.; Crawford, James H.

1999-03-01

Advanced very high resolution radiometer 1.1 km resolution satellite radiance data were used to locate active fires throughout much of the tropical region during NASA's Global Tropospheric Experiment (GTE) Pacific Exploratory Mission-Tropics (PEM-Tropics A) aircraft campaign, held in September and October 1996. The spatial and temporal distributions of the fires in Australia, southern Africa, and South America are presented here. The number of fires over northern Australia, central Africa, and South America appeared to decrease toward the end of the mission period. Fire over eastern Australia was widespread, and temporal patterns showed a somewhat consistent amount of burning with periodic episodes of enhanced fire counts observed. At least one episode of enhanced fire counts corresponded to the passage of a frontal system which brought conditions conducive to fire to the region, with strong westerlies originating over the hot, dry interior continent. Regions that were affected by lower than normal rainfall during the previous wet season (e.g., northern Australia and southwestern Africa) showed relatively few fires during this period. This is consistent with a drought-induced decrease in vegetation and therefore a decreased availability of fuel for burning. Alternatively, a heavier than normal previous wet season along the southeastern coast of South Africa may have contributed to high fuel loading and an associated relatively heavy amount of burning compared to data from previous years.

Sensitivity of the tropical climate to an interhemispheric thermal gradient: the role of tropical ocean dynamics

Science.gov (United States)

Talento, Stefanie; Barreiro, Marcelo

2018-03-01

This study aims to determine the role of the tropical ocean dynamics in the response of the climate to extratropical thermal forcing. We analyse and compare the outcomes of coupling an atmospheric general circulation model (AGCM) with two ocean models of different complexity. In the first configuration the AGCM is coupled with a slab ocean model while in the second a reduced gravity ocean (RGO) model is additionally coupled in the tropical region. We find that the imposition of extratropical thermal forcing (warming in the Northern Hemisphere and cooling in the Southern Hemisphere with zero global mean) produces, in terms of annual means, a weaker response when the RGO is coupled, thus indicating that the tropical ocean dynamics oppose the incoming remote signal. On the other hand, while the slab ocean coupling does not produce significant changes to the equatorial Pacific sea surface temperature (SST) seasonal cycle, the RGO configuration generates strong warming in the central-eastern basin from April to August balanced by cooling during the rest of the year, strengthening the seasonal cycle in the eastern portion of the basin. We hypothesize that such changes are possible via the dynamical effect that zonal wind stress has on the thermocline depth. We also find that the imposed extratropical pattern affects El Niño-Southern Oscillation, weakening its amplitude and low-frequency behaviour.

Genomic-based-breeding tools for tropical maize improvement.

Science.gov (United States)

Chakradhar, Thammineni; Hindu, Vemuri; Reddy, Palakolanu Sudhakar

2017-12-01

Maize has traditionally been the main staple diet in the Southern Asia and Sub-Saharan Africa and widely grown by millions of resource poor small scale farmers. Approximately, 35.4 million hectares are sown to tropical maize, constituting around 59% of the developing worlds. Tropical maize encounters tremendous challenges besides poor agro-climatic situations with average yields recorded <3 tones/hectare that is far less than the average of developed countries. On the contrary to poor yields, the demand for maize as food, feed, and fuel is continuously increasing in these regions. Heterosis breeding introduced in early 90 s improved maize yields significantly, but genetic gains is still a mirage, particularly for crop growing under marginal environments. Application of molecular markers has accelerated the pace of maize breeding to some extent. The availability of array of sequencing and genotyping technologies offers unrivalled service to improve precision in maize-breeding programs through modern approaches such as genomic selection, genome-wide association studies, bulk segregant analysis-based sequencing approaches, etc. Superior alleles underlying complex traits can easily be identified and introgressed efficiently using these sequence-based approaches. Integration of genomic tools and techniques with advanced genetic resources such as nested association mapping and backcross nested association mapping could certainly address the genetic issues in maize improvement programs in developing countries. Huge diversity in tropical maize and its inherent capacity for doubled haploid technology offers advantage to apply the next generation genomic tools for accelerating production in marginal environments of tropical and subtropical world. Precision in phenotyping is the key for success of any molecular-breeding approach. This article reviews genomic technologies and their application to improve agronomic traits in tropical maize breeding has been reviewed in

Using Leaf Samples to Establish a Library of Tropical Leaf Fingerprints

Science.gov (United States)

Ngo, P.; Nguyen, R.; Anderson, C.; Weiss, P.

2010-12-01

Variation in leaf chemistry is directly expressed in spectroscopic patterns of tropical canopies. The goal of the Spectranomics project is to explore this variation in the hopes of developing a method to measure tropical forest diversity remotely from airborne or space-bound spectroscopy in the future. We analyzed tomato leaves for various chemical compositions to better understand the Spectranomics approach to quantifying chemical data of tropical species. We also compared our data to standard data in each analysis. Our results allow us to give the tomato leaves a chemical signature in which we are able to use to compare to other leaf samples. Using this process, we are able to create a library of leaf signatures and document the variety of tree species in tropical forests around the world.

Tropical Cyclone Report, 1988

Science.gov (United States)

1988-01-01

Cmdr. David Gray; National Weather Service 5. Cooperation with the Naval Environmental Pacific Region for the startup of 24-hour operatiois at Ponape...0.1 27.7 TOTAL CASES 3 1 1 4 12 27 54 56 30 25 7 1 221 * (GRAY, 1979) TABLE 4-3 ANNUAL VARIATION C SOTR MUSHER TROPICAL CYCLOUZ BY O(EN BASIN SOUTH

Utilization of tropical rabbits

African Journals Online (AJOL)

5,0' a,b"differ (P<0,05) for reproducing rabbits, and may aid the prevention of enteric diseases. In Trial 3, ADG of several tropical legumes was the same as that obtained with alfalfa (Table 3). Gains with guinea grass, cassava, stylosanthes and the winged bean were lower than with alfalfa. Digestibilityof the protein and fibre ...

Malaria and Tropical Travel

Centers for Disease Control (CDC) Podcasts

2008-05-15

Malaria is a serious mosquito-borne disease that can lead to death. This podcast discusses malaria risk when traveling to tropical areas, as well as how to protect yourself and your family from malaria infection.  Created: 5/15/2008 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED).   Date Released: 5/29/2008.

What do we know about Indonesian tropical lakes? Insights from high frequency measurement

Science.gov (United States)

Budi Santoso, Arianto; Triwisesa, Endra; Fakhrudin, Muh.; Harsono, Eko; Agita Rustini, Hadiid

2018-02-01

When measuring ecological variables in lakes, sampling frequency is critical in capturing an environmental pattern. Discrete sampling of traditional monitoring programs is likely to result in vital knowledge gaps in understanding any processes particularly those with fine temporal scale characteristics. The development of high frequency measurements offer a sophisticated range of information in recording any events in lakes at a finer time scale. We present physical indices of a tropical deep Lake Maninjau arrayed from OnLine Monitoring System (OLM). It is revealed that Lake Maninjau mostly has a diurnal thermal stratification pattern. The calculated lake stability (Schmidt stability), however, follows a seasonal pattern; low in December-January and around August, and high in May and September. Using a 3D numerical model simulation (ELCOM), we infer how wind and solar radiation intensity control lake’s temperature profiles. In this review, we highlight the needs of high frequency measurement establishment in Indonesian tropical lakes to better understand the unique processes and to support the authorities’ decision making in maximizing the provision of ecosystem services supplied by lakes and reservoirs.

The biodiversity cost of carbon sequestration in tropical savanna.

Science.gov (United States)

Abreu, Rodolfo C R; Hoffmann, William A; Vasconcelos, Heraldo L; Pilon, Natashi A; Rossatto, Davi R; Durigan, Giselda

2017-08-01

Tropical savannas have been increasingly viewed as an opportunity for carbon sequestration through fire suppression and afforestation, but insufficient attention has been given to the consequences for biodiversity. To evaluate the biodiversity costs of increasing carbon sequestration, we quantified changes in ecosystem carbon stocks and the associated changes in communities of plants and ants resulting from fire suppression in savannas of the Brazilian Cerrado, a global biodiversity hotspot. Fire suppression resulted in increased carbon stocks of 1.2 Mg ha -1 year -1 since 1986 but was associated with acute species loss. In sites fully encroached by forest, plant species richness declined by 27%, and ant richness declined by 35%. Richness of savanna specialists, the species most at risk of local extinction due to forest encroachment, declined by 67% for plants and 86% for ants. This loss highlights the important role of fire in maintaining biodiversity in tropical savannas, a role that is not reflected in current policies of fire suppression throughout the Brazilian Cerrado. In tropical grasslands and savannas throughout the tropics, carbon mitigation programs that promote forest cover cannot be assumed to provide net benefits for conservation.

Frequency of Tropical Ocean Deep Convection and Global Warming

Science.gov (United States)

Aumann, H. H.; Behrangi, A.; Ruzmaikin, A.

2017-12-01

The average of 36 CMIP5 models predicts about 3K of warming and a 4.7% increase in precipitation for the tropical oceans with a doubling of the CO2 by the end of this century. For this scenario we evaluate the increase in the frequency of Deep Convective Clouds (DCC) in the tropical oceans. We select only DCC which reach or penetrate the tropopause in the 15 km AIRS footprint. The evaluation is based on Probability Distribution Functions (PDFs) of the current temperatures of the tropical oceans, those predicted by the mean of the CMIP5 models and the PDF of the DCC process. The PDF of the DCC process is derived from the Atmospheric Infrared Sounder (AIRS) between the years 2003 and 2016. During this time the variability due Enso years provided a 1 K p-p change in the mean tropical SST. The key parameter is the SST associated with the onset of the DCC process. This parameter shifts only 0.5 K for each K of warming of the oceans. As a result the frequency of DCC is expected to increases by the end of this century by about 50% above the current frequency.

Regional impacts of ocean color on tropical Pacific variability

Directory of Open Access Journals (Sweden)

W. Anderson

2009-08-01

Full Text Available The role of the penetration length scale of shortwave radiation into the surface ocean and its impact on tropical Pacific variability is investigated with a fully coupled ocean, atmosphere, land and ice model. Previous work has shown that removal of all ocean color results in a system that tends strongly towards an El Niño state. Results from a suite of surface chlorophyll perturbation experiments show that the mean state and variability of the tropical Pacific is highly sensitive to the concentration and distribution of ocean chlorophyll. Setting the near-oligotrophic regions to contain optically pure water warms the mean state and suppresses variability in the western tropical Pacific. Doing the same above the shadow zones of the tropical Pacific also warms the mean state but enhances the variability. It is shown that increasing penetration can both deepen the pycnocline (which tends to damp El Niño while shifting the mean circulation so that the wind response to temperature changes is altered. Depending on what region is involved this change in the wind stress can either strengthen or weaken ENSO variability.

Cross inoculation of anthracnose pathogens infecting various tropical fruits

Science.gov (United States)

Suparman; Rahmiyah, M.; Pujiastuti, Y.; Gunawan, B.; Arsi

2018-01-01

Anthracnose disease is very important disease of tropical fruits causing significant yield losses. The disease is caused by Colletotrichum spp. and infects almost all tropical fruit species, especially the succulent ones. Various species of Colletotrichum infect various tropical fruits and there are possibilities for cross inoculation to occur among tropical fruits which might cause severe infection. An experimental research was conducted to examine the effect of cross inoculation of anthracnose pathogen among papaya, eggplant, chili and common bean on the infection development and severity of the disease on each inoculated fruit species. Colletotrichum spp. were isolated from naturally infected papaya, eggplant, chili and common bean. Each fungal isolate was purified and identified to determine the species name. The spores of each isolate were then used to separately inoculate healthy and sterilized papaya, eggplant, chili and common bean. The results showed that cross infection developed on chili, eggplant and papaya but not on bean. Chili showed the highest susceptibility to all Colletotrichum isolates and significantly different from eggplant and papaya. The anthracnose pathogen isolated from common bean showed no pathogenicity to other hosts and might be used as cross protection inoculant to the disease in the other hosts.

Controls on the meridional extent of tropical precipitation and its contraction under global warming

Science.gov (United States)

Donohoe, A.

2017-12-01

A method for decomposing changes and variability in the spatial structure of tropical precipitation into shifting (meridional translation), contracting, and intensifying modes of variability is introduced. We demonstrate that the shifting mode of tropical precipitation explains very little (20%) more of the tropical precipitation changes and variability. Furthermore, the contraction of tropical precipitation is highly correlated (R2 > 0.95) with an intensification of the precipitation in both the observations and forced modeled simulations. These results suggest that the simultaneous contraction and intensification of tropical precipitation is the dominant mode of variability and changes under external forcing. We speculate that tropical surface temperature controls this concurrent variability. Indeed, models robustly predict that tropical precipitation increases and meridionally contracts in response to increased CO2 and is reduced and meridionally expanded under glacial forcing and boundary conditions. In contrast, the directionality of the tropical precipitation shift is both ambiguous and small in magnitude in response to increased CO2. Furthermore, the ratio of the contraction/expansion to intensification/reduction is consistent in the continuum of climate states from the glacial climate to a modern climate to a 4XCO2 climate suggesting that the intensification and contraction are linked together via a single mechanism. We examine two mechanisms responsible for the contraction of the precipitation under global warming : i. the reduction of the seasonal cycle of energy input to the atmosphere due to sea ice retreat that results in the tropical precipitation remaining closer to the equator during the solsticial seasons and; ii. the increased gross moist stability of the tropical atmosphere as the surface warms resulting in a weaker cross-equatorial Hadley circulation during the solsticial seasons.

Pan-Tropical Analysis of Climate Effects on Seasonal Tree Growth

Science.gov (United States)

Wagner, Fabien; Rossi, Vivien; Aubry-Kientz, Mélaine; Bonal, Damien; Dalitz, Helmut; Gliniars, Robert; Stahl, Clément; Trabucco, Antonio; Hérault, Bruno

2014-01-01

Climate models predict a range of changes in tropical forest regions, including increased average temperatures, decreased total precipitation, reduced soil moisture and alterations in seasonal climate variations. These changes are directly related to the increase in anthropogenic greenhouse gas concentrations, primarily CO2. Assessing seasonal forest growth responses to climate is of utmost importance because woody tissues, produced by photosynthesis from atmospheric CO2, water and light, constitute the main component of carbon sequestration in the forest ecosystem. In this paper, we combine intra-annual tree growth measurements from published tree growth data and the corresponding monthly climate data for 25 pan-tropical forest sites. This meta-analysis is designed to find the shared climate drivers of tree growth and their relative importance across pan-tropical forests in order to improve carbon uptake models in a global change context. Tree growth reveals significant intra-annual seasonality at seasonally dry sites or in wet tropical forests. Of the overall variation in tree growth, 28.7% was explained by the site effect, i.e. the tree growth average per site. The best predictive model included four climate variables: precipitation, solar radiation (estimated with extrasolar radiation reaching the atmosphere), temperature amplitude and relative soil water content. This model explained more than 50% of the tree growth variations across tropical forests. Precipitation and solar radiation are the main seasonal drivers of tree growth, causing 19.8% and 16.3% of the tree growth variations. Both have a significant positive association with tree growth. These findings suggest that forest productivity due to tropical tree growth will be reduced in the future if climate extremes, such as droughts, become more frequent. PMID:24670981

Bibliometry of Costa Rica biodiversity studies published in the Revista de Biología Tropical/International Journal of Tropical Biology and Conservation (2000-2010): the content and importance of a leading tropical biology journal in its 60th anniversary.

Science.gov (United States)

Nielsen-Muñoz, Vanessa; Azofeifa-Mora, Ana Beatriz; Monge-Nájera, Julián

2012-12-01

Central America is recognized as a mega diverse "hot-spot" and one of its smaller countries, Costa Rica, as one of the world's leaders in the study and conservation of tropical biodiversity. For this study, inspired by the 60th anniversary of the journal Revista de Biología Tropical, we tabulated all the scientific production on Costa Rican biodiversity published in Revista de Biología Tropical between 2000 and 2010. Most articles are zoological (62%) and 67% of authors had only one publication in the jounal within that period. A 54% of articles were published in English and 46% in Spanish. A 41% of articles were written in collaboration among Costa Rican institutions and 36% in collaboration with foreign institutions. The Collaboration Index was 2.53 signatures per article. Visibility in American sources was 56% in Google Scholar and 42.66% in the Web of Science, but the real visibility and impact are unknown because these sources exclude the majority of tropical journals. Revista de Biología Tropical is the main output channel for Costa Rican biology and despite its small size, Costa Rica occupies the 10th. place in productivity among Latin American countries, with productivity and impact levels that compare favorably with larger countries such as Brazil, Mexico, Argentina and Chile.

Staying cool: preadaptation to temperate climates required for colonising tropical alpine-like environments

Directory of Open Access Journals (Sweden)

Berit Gehrke

2018-04-01

Full Text Available Plant species tend to retain their ancestral ecology, responding to temporal, geographic and climatic changes by tracking suitable habitats rather than adapting to novel conditions. Nevertheless, transitions into different environments or biomes still seem to be common. Especially intriguing are the tropical alpine-like areas found on only the highest mountainous regions surrounded by tropical environments. Tropical mountains are hotspots of biodiversity, often with striking degrees of endemism at higher elevations. On these mountains, steep environmental gradients and high habitat heterogeneity within small spaces coincide with astounding species diversity of great conservation value. The analysis presented here shows that the importance of in situ speciation in tropical alpine-like areas has been underestimated. Additionally and contrary to widely held opinion, the impact of dispersal from other regions with alpine-like environments is relatively minor compared to that of immigration from other biomes with a temperate (but not alpine-like climate. This suggests that establishment in tropical alpine-like regions is favoured by preadaptation to a temperate, especially aseasonal, freezing regime such as the cool temperate climate regions in the Tropics. Furthermore, emigration out of an alpine-like environment is generally rare, suggesting that alpine-like environments – at least tropical ones – are species sinks.

Road-networks, a practical indicator of human impacts on biodiversity in Tropical forests

International Nuclear Information System (INIS)

Hosaka, T; Yamada, T; Okuda, T

2014-01-01

Tropical forests sustain the most diverse plants and animals in the world, but are also being lost most rapidly. Rapid assessment and monitoring using remote sensing on biodiversity of tropical forests is needed to predict and evaluate biodiversity loss by human activities. Identification of reliable indicators of forest biodiversity and/or its loss is an urgent issue. In the present paper, we propose the density of road networks in tropical forests can be a good and practical indicator of human impacts on biodiversity in tropical forests through reviewing papers and introducing our preliminary survey in peninsular Malaysia. Many previous studies suggest a strong negative impact of forest roads on biodiversity in tropical rainforests since they changes microclimate, soil properties, drainage patterns, canopy openness and forest accessibility. Moreover, our preliminary survey also showed that even a narrow logging road (6 m wide) significantly lowered abundance of dung beetles (well-known bio-indicator in biodiversity survey in tropical forests) near the road. Since these road networks are readily to be detected with remote sensing approach such as aerial photographs and Lider, regulation and monitoring of the road networks using remote sensing techniques is a key to slow down the rate of biodiversity loss due to forest degradation in tropical forests

Road-networks, a practical indicator of human impacts on biodiversity in Tropical forests

Science.gov (United States)

Hosaka, T.; Yamada, T.; Okuda, T.

2014-02-01

Tropical forests sustain the most diverse plants and animals in the world, but are also being lost most rapidly. Rapid assessment and monitoring using remote sensing on biodiversity of tropical forests is needed to predict and evaluate biodiversity loss by human activities. Identification of reliable indicators of forest biodiversity and/or its loss is an urgent issue. In the present paper, we propose the density of road networks in tropical forests can be a good and practical indicator of human impacts on biodiversity in tropical forests through reviewing papers and introducing our preliminary survey in peninsular Malaysia. Many previous studies suggest a strong negative impact of forest roads on biodiversity in tropical rainforests since they changes microclimate, soil properties, drainage patterns, canopy openness and forest accessibility. Moreover, our preliminary survey also showed that even a narrow logging road (6 m wide) significantly lowered abundance of dung beetles (well-known bio-indicator in biodiversity survey in tropical forests) near the road. Since these road networks are readily to be detected with remote sensing approach such as aerial photographs and Lider, regulation and monitoring of the road networks using remote sensing techniques is a key to slow down the rate of biodiversity loss due to forest degradation in tropical forests.

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

Sensitivity of tropical carbon to climate change constrained by carbon dioxide variability.

Science.gov (United States)

Cox, Peter M; Pearson, David; Booth, Ben B; Friedlingstein, Pierre; Huntingford, Chris; Jones, Chris D; Luke, Catherine M

2013-02-21

The release of carbon from tropical forests may exacerbate future climate change, but the magnitude of the effect in climate models remains uncertain. Coupled climate-carbon-cycle models generally agree that carbon storage on land will increase as a result of the simultaneous enhancement of plant photosynthesis and water use efficiency under higher atmospheric CO(2) concentrations, but will decrease owing to higher soil and plant respiration rates associated with warming temperatures. At present, the balance between these effects varies markedly among coupled climate-carbon-cycle models, leading to a range of 330 gigatonnes in the projected change in the amount of carbon stored on tropical land by 2100. Explanations for this large uncertainty include differences in the predicted change in rainfall in Amazonia and variations in the responses of alternative vegetation models to warming. Here we identify an emergent linear relationship, across an ensemble of models, between the sensitivity of tropical land carbon storage to warming and the sensitivity of the annual growth rate of atmospheric CO(2) to tropical temperature anomalies. Combined with contemporary observations of atmospheric CO(2) concentration and tropical temperature, this relationship provides a tight constraint on the sensitivity of tropical land carbon to climate change. We estimate that over tropical land from latitude 30° north to 30° south, warming alone will release 53 ± 17 gigatonnes of carbon per kelvin. Compared with the unconstrained ensemble of climate-carbon-cycle projections, this indicates a much lower risk of Amazon forest dieback under CO(2)-induced climate change if CO(2) fertilization effects are as large as suggested by current models. Our study, however, also implies greater certainty that carbon will be lost from tropical land if warming arises from reductions in aerosols or increases in other greenhouse gases.

Ice nucleation and dehydration in the Tropical Tropopause Layer.

Science.gov (United States)

Jensen, Eric J; Diskin, Glenn; Lawson, R Paul; Lance, Sara; Bui, T Paul; Hlavka, Dennis; McGill, Matthew; Pfister, Leonhard; Toon, Owen B; Gao, Rushan

2013-02-05

Optically thin cirrus near the tropical tropopause regulate the humidity of air entering the stratosphere, which in turn has a strong influence on the Earth's radiation budget and climate. Recent high-altitude, unmanned aircraft measurements provide evidence for two distinct classes of cirrus formed in the tropical tropopause region: (i) vertically extensive cirrus with low ice number concentrations, low extinctions, and large supersaturations (up to ∼70%) with respect to ice; and (ii) vertically thin cirrus layers with much higher ice concentrations that effectively deplete the vapor in excess of saturation. The persistent supersaturation in the former class of cirrus is consistent with the long time-scales (several hours or longer) for quenching of vapor in excess of saturation given the low ice concentrations and cold tropical tropopause temperatures. The low-concentration clouds are likely formed on a background population of insoluble particles with concentrations less than 100 L(-1) (often less than 20 L(-1)), whereas the high ice concentration layers (with concentrations up to 10,000 L(-1)) can only be produced by homogeneous freezing of an abundant population of aqueous aerosols. These measurements, along with past high-altitude aircraft measurements, indicate that the low-concentration cirrus occur frequently in the tropical tropopause region, whereas the high-concentration cirrus occur infrequently. The predominance of the low-concentration clouds means cirrus near the tropical tropopause may typically allow entry of air into the stratosphere with as much as ∼1.7 times the ice saturation mixing ratio.

Floristic structure and biomass distribution of a tropical seasonal rain forest in Xishuangbanna, southwest China

Energy Technology Data Exchange (ETDEWEB)

Shanmughavel, P.; Zheng Zheng; Sha Liqing; Cao Min [Chinese Academy of Sciences, Kunming (China). Dept. of Forest Ecology

2001-07-01

The aim of this research was to study the forest community structure, tree species diversity and biomass production of a tropical seasonal rain forest in Xishuangbanna, southwest China. The community structure showed a diversified species composition and supported many species of economic significance. This tropical rain forest in closely related to Malaysian forests. The biomass and its distribution were studied using standard regression analysis and the clear-cut method for shrubs and herbs. The total biomass was 360.9 t/ha and its allocation in different layers was: tree layer 352.5 t/ha, shrub layer 4.7 t/ha, liana 3.1 t/ha and herb layer 0.5 t/ha. Most of the biomass was concentrated in the trees: stem 241.2 t/ha, root 69.6 t/ha, branch 37.2 t/ha and leaves 4.3 t/ha. The DBH class allocation of the tree biomass was concentrated in the middle DBH class. The biomass of six DBH classes from 20 to 80 cm was 255.4 t/ha. There are twenty-six species with biomass over 0.5% of the total biomass of the tree layer, and three species with biomass over 5%, i.e., Pometia tomentosa, Barringtonia macrostachya (5.4%) and Terminalia myriocarpa (5.2%). Data on stem, branch, leaves and root of the individual tree species were used to develop regression models. D{sup 2}H was found to be the best estimator of the biomass in this tropical rain forest. However, higher biomass figures have been reported from tropical forests elsewhere e.g., 415-520 t/ha in the tropical forests of Cambodia, the tropical moist mixed dipterocarp forests, and the tropical moist logged moist evergreen-high, medium, and low yield forests of Sri Lanka. In some forests, lower accumulation of biomass was reported, e.g., 10-295 t/ha in the tropical moist forests of Bangladesh, the tropical moist dense forest of Cambodia, the tropical dry forests of India, the tropical moist forests of Peninsular-Malaysia, the tropical moist mixed dipterocarp forests of Sarawak-Malaysia, the tropical evergreen forests of

Vitamin D Deficiency in Risk Groups Living in Tropical Curacao

NARCIS (Netherlands)

Leenders, T. J. M.; van Eijndhoven, F. H. A.; van der Veer, E.; Muskiet, F. A. J.

Objective: Curacao (12 degrees 10N, 69 degrees 0W) is characterized by whole year abundant sunshine (8-10 hours/day). We challenged the automatic assumption that people living in tropical countries do not have a high risk of vitamin D deficiency, and investigated the vitamin D status in a tropical

Climate change, allergy and asthma, and the role of tropical forests.

Science.gov (United States)

D'Amato, Gennaro; Vitale, Carolina; Rosario, Nelson; Neto, Herberto Josè Chong; Chong-Silva, Deborah Carla; Mendonça, Francisco; Perini, Josè; Landgraf, Loraine; Solé, Dirceu; Sánchez-Borges, Mario; Ansotegui, Ignacio; D'Amato, Maria

2017-01-01

Tropical forests cover less than 10 per cent of all land area (1.8 × 107 km 2 ) and over half of the tropical-forest area (1.1 × 107 Km 2 ) is represented by humid tropical forests (also called tropical rainforests). The Amazon basin contains the largest rainforest on Earth, almost 5.8 million km 2 , and occupies about 40% of South America; more than 60% of the basin is located in Brazil and the rest in Bolivia, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela. Over the past decade the positive role of tropical rainforests in capturing large amounts of atmospheric carbon dioxide (CO 2 ) has been demonstrated. In response to the increase in atmospheric CO 2 concentration, tropical forests act as a global carbon sink. Accumulation of carbon in the tropical terrestrial biosphere strongly contributes to slowing the rate of increase of CO 2 into the atmosphere, thus resulting in the reduction of greenhouse gas effect. Tropical rainforests have been estimated to account for 32-36% of terrestrial Net Primary Productivity (NPP) that is the difference between total forest photosynthesis and plant respiration. Tropical rainforests have been acting as a strong carbon sink in this way for decades. However, over the past years, increased concentrations of greenhouse gases, and especially CO 2 , in the atmosphere have significantly affected the net carbon balance of tropical rainforests, and have warmed the planet substantially driving climate changes through more severe and prolonged heat waves, variability in temperature, increased air pollution, forest fires, droughts, and floods. The role of tropical forests in mitigating climate change is therefore critical. Over the past 30 years almost 600,000 km 2 have been deforested in Brazil alone due to the rapid development of Amazonia, this is the reason why currently the region is one of the 'hotspots' of global environmental change on the planet. Deforestation represents the second largest

Multi-Scale Models for the Scale Interaction of Organized Tropical Convection

Science.gov (United States)

Yang, Qiu

Assessing the upscale impact of organized tropical convection from small spatial and temporal scales is a research imperative, not only for having a better understanding of the multi-scale structures of dynamical and convective fields in the tropics, but also for eventually helping in the design of new parameterization strategies to improve the next-generation global climate models. Here self-consistent multi-scale models are derived systematically by following the multi-scale asymptotic methods and used to describe the hierarchical structures of tropical atmospheric flows. The advantages of using these multi-scale models lie in isolating the essential components of multi-scale interaction and providing assessment of the upscale impact of the small-scale fluctuations onto the large-scale mean flow through eddy flux divergences of momentum and temperature in a transparent fashion. Specifically, this thesis includes three research projects about multi-scale interaction of organized tropical convection, involving tropical flows at different scaling regimes and utilizing different multi-scale models correspondingly. Inspired by the observed variability of tropical convection on multiple temporal scales, including daily and intraseasonal time scales, the goal of the first project is to assess the intraseasonal impact of the diurnal cycle on the planetary-scale circulation such as the Hadley cell. As an extension of the first project, the goal of the second project is to assess the intraseasonal impact of the diurnal cycle over the Maritime Continent on the Madden-Julian Oscillation. In the third project, the goals are to simulate the baroclinic aspects of the ITCZ breakdown and assess its upscale impact on the planetary-scale circulation over the eastern Pacific. These simple multi-scale models should be useful to understand the scale interaction of organized tropical convection and help improve the parameterization of unresolved processes in global climate models.

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...

High resolution analysis of tropical forest fragmentation and its impact on the global carbon cycle

Science.gov (United States)

Brinck, Katharina; Fischer, Rico; Groeneveld, Jürgen; Lehmann, Sebastian; Dantas de Paula, Mateus; Pütz, Sandro; Sexton, Joseph O.; Song, Danxia; Huth, Andreas

2017-03-01

Deforestation in the tropics is not only responsible for direct carbon emissions but also extends the forest edge wherein trees suffer increased mortality. Here we combine high-resolution (30 m) satellite maps of forest cover with estimates of the edge effect and show that 19% of the remaining area of tropical forests lies within 100 m of a forest edge. The tropics house around 50 million forest fragments and the length of the world's tropical forest edges sums to nearly 50 million km. Edge effects in tropical forests have caused an additional 10.3 Gt (2.1-14.4 Gt) of carbon emissions, which translates into 0.34 Gt per year and represents 31% of the currently estimated annual carbon releases due to tropical deforestation. Fragmentation substantially augments carbon emissions from tropical forests and must be taken into account when analysing the role of vegetation in the global carbon cycle.

Infaunal macrobenthic community of soft bottom sediment in a tropical shelf

Digital Repository Service at National Institute of Oceanography (India)

Jayaraj, K.A.; Jacob, J.; DineshKumar, P.K.

Studies of benthic communities in tropical shelf waters are limited. In this study, we deal with the infaunal benthic community of soft bottom sediment of the tropical eastern Arabian Sea shelf. Benthic macroinfauna was sampled with a Smith...

Quantifying tropical peatland dissolved organic carbon (DOC) using UV-visible spectroscopy.

Science.gov (United States)

Cook, Sarah; Peacock, Mike; Evans, Chris D; Page, Susan E; Whelan, Mick J; Gauci, Vincent; Kho, Lip Khoon

2017-05-15

UV-visible spectroscopy has been shown to be a useful technique for determining dissolved organic carbon (DOC) concentrations. However, at present we are unaware of any studies in the literature that have investigated the suitability of this approach for tropical DOC water samples from any tropical peatlands, although some work has been performed in other tropical environments. We used water samples from two oil palm estates in Sarawak, Malaysia to: i) investigate the suitability of both single and two-wavelength proxies for tropical DOC determination; ii) develop a calibration dataset and set of parameters to calculate DOC concentrations indirectly; iii) provide tropical researchers with guidance on the best spectrophotometric approaches to use in future analyses of DOC. Both single and two-wavelength model approaches performed well with no one model significantly outperforming the other. The predictive ability of the models suggests that UV-visible spectroscopy is both a viable and low cost method for rapidly analyzing DOC in water samples immediately post-collection, which can be important when working at remote field sites with access to only basic laboratory facilities. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Environmental determinants of tropical forest and savanna distribution: A quantitative model evaluation and its implication

Science.gov (United States)

Zeng, Zhenzhong; Chen, Anping; Piao, Shilong; Rabin, Sam; Shen, Zehao

2014-07-01

The distributions of tropical ecosystems are rapidly being altered by climate change and anthropogenic activities. One possible trend—the loss of tropical forests and replacement by savannas—could result in significant shifts in ecosystem services and biodiversity loss. However, the influence and the relative importance of environmental factors in regulating the distribution of tropical forest and savanna biomes are still poorly understood, which makes it difficult to predict future tropical forest and savanna distributions in the context of climate change. Here we use boosted regression trees to quantitatively evaluate the importance of environmental predictors—mainly climatic, edaphic, and fire factors—for the tropical forest-savanna distribution at a mesoscale across the tropics (between 15°N and 35°S). Our results demonstrate that climate alone can explain most of the distribution of tropical forest and savanna at the scale considered; dry season average precipitation is the single most important determinant across tropical Asia-Australia, Africa, and South America. Given the strong tendency of increased seasonality and decreased dry season precipitation predicted by global climate models, we estimate that about 28% of what is now tropical forest would likely be lost to savanna by the late 21st century under the future scenario considered. This study highlights the importance of climate seasonality and interannual variability in predicting the distribution of tropical forest and savanna, supporting the climate as the primary driver in the savanna biogeography.

Pesticides in tropical marine environments: Assessing their fate

International Nuclear Information System (INIS)

Carvalho, F.P.

1993-01-01

While forecasts of economic and population trends are notoriously contentious, it seems to be fairly widely accepted that there will be approximately 11,000 million people to feed in the year 2050, which is about twice as many as there were in 1990. There seems little doubt that pesticides will remain an essential component of many agricultural systems. Although it is estimated that insect pests alone still destroy about one-third of the world's crops, yields would probably decline by a further 30% to 75% without crop protection chemicals. It is hardly surprising therefore that worldwide pesticide usage is on the order of 5 million tons per year with a value of US $26 billion. Data on the behaviour of pesticides in the tropical marine environment are very limited in comparison with information on the fate of pesticides in temperate regions. Preliminary surveys carried out be the IAEA's Marine Environment Laboratory (IAEA-MEL) in coastal lagoons in Central America indicate the presence of high concentrations of DDT and its metabolites in sediments and aquatic organisms. OP compounds, such as chlorpyrifos, were also found to be widespread contaminants in these lagoons. To develop relevant studies, the IAEA is organizing a co-ordinated research programme (CRP) through its Laboratory at Monaco and the Joint FAO/IAEA Division. The CRP is entitled the Distribution, Fate, and Effects of Pesticides in Biota in the Tropical Environment; support has been offered by the Swedish International Development Agency (SIDA). It will concentrate on various aspects of the problem. 2 figs

A Review of Parametric Descriptions of Tropical Cyclone Wind-Wave Generation

Directory of Open Access Journals (Sweden)

Ian R. Young

2017-10-01

Full Text Available More than three decades of observations of tropical cyclone wind and wave fields have resulted in a detailed understanding of wave-growth dynamics, although details of the physics are still lacking. These observations are presented in a consistent manner, which provides the basis to be able to characterize the full wave spectrum in a parametric form throughout tropical cyclones. The data clearly shows that an extended fetch model can be used to represent the maximum significant wave height in such storms. The shape stabilizing influence of nonlinear interactions means that the spectral shape is remarkably similar to fetch-limited cases. As such, the tropical cyclone spectrum can also be described by using well-known parametric models. A detailed process is described to parameterize the wave spectrum at any point in a tropical cyclone.

Tropical-extratropical climate interaction as revealed in idealized coupled climate model experiments

Energy Technology Data Exchange (ETDEWEB)

Yang, Haijun [Peking University, Department of Atmospheric Science and Laboratory for Severe Storm and Flood Disasters, School of Physics, Beijing (China); Liu, Zhengyu [University of Wisconsin-Madison, Center for Climatic Research and Department of the Atmospheric and Oceanic Sciences, Madison, WI (United States)

2005-06-01

Tropical-extratropical climate interactions are studied by idealized experiments with a prescribed 2 C SST anomaly at different latitude bands in a coupled climate model. Instead of focusing on intrinsic climate variability, this work investigates the mean climate adjustment to remote external forcing. The extratropical impact on tropical climate can be as strong as the tropical impact on extratropical climate, with the remote sea surface temperature (SST) response being about half the magnitude of the imposed SST change in the forcing region. The equatorward impact of extratropical climate is accomplished by both the atmospheric bridge and the oceanic tunnel. About two-thirds of the tropical SST change comes from the atmospheric bridge, while the remaining one-third comes from the oceanic tunnel. The equatorial SST increase is first driven by the reduced latent heat flux and the weakened poleward surface Ekman transport, and then enhanced by the decrease in subtropical cells' strength and the equatorward subduction of warm anomalies. In contrast, the poleward impact of tropical climate is accomplished mainly by the atmospheric bridge, which is responsible for extratropical temperature changes in both the surface and subsurface. Sensitivity experiments also show the dominant role of the Southern Hemisphere oceans in the tropical climate change. (orig.)

An engine for global plant diversity: Highest evolutionary turnover and emigration in the American tropics

Directory of Open Access Journals (Sweden)

Alexandre eAntonelli

2015-04-01

Full Text Available Understanding the processes that have generated the latitudinal biodiversity gradient and the continental differences in tropical biodiversity remains a major goal of evolutionary biology. Here we estimate the timing and direction of range shifts of extant flowering plants (angiosperms between tropical and non-tropical zones, and into and out of the major tropical regions of the world. We then calculate rates of speciation and extinction taking into account incomplete taxonomic sampling. We use a recently published fossil calibrated phylogeny and apply novel bioinformatic tools to code species into user-defined polygons. We reconstruct biogeographic history using stochastic character mapping to compute relative numbers of range shifts in proportion to the number of available lineages through time. Our results, based on the analysis of c. 22,600 species and c. 20 million geo-referenced occurrence records, show no significant differences between the speciation and extinction of tropical and non-tropical angiosperms. This suggests that at least in plants, the tropical biodiversity gradient primarily derives from other factors than differential rates of diversification. In contrast, the outstanding species richness found today in the American tropics (the Neotropics, as compared to tropical Africa and tropical Asia, is associated with significantly higher speciation and extinction rates. This suggests an exceedingly rapid evolutionary turnover, i.e. Neotropical species being formed and replaced by one another at unparalleled rates. In addition, tropical America stands out from other continents by having ‘pumped out’ more species than it received through most of the last 66 million years. These results imply that the Neotropics have acted as an engine for global plant diversity.

Tropical Journal of Medical Research

African Journals Online (AJOL)

Tropical Journal of Medical Research publishes original research work, review articles, important case report, short communications, and innovations in medicine and related fields. Vol 16, No 2 (2012). DOWNLOAD FULL TEXT Open Access DOWNLOAD FULL TEXT Subscription or Fee Access. Table of Contents. Articles ...

Podoconiosis, a neglected tropical disease

NARCIS (Netherlands)

Korevaar, D. A.; Visser, B. J.

2012-01-01

Podoconiosis or 'endemic non-filarial elephantiasis' is a tropical disease caused by exposure of bare feet to irritant alkaline clay soils. This causes an asymmetrical swelling of the feet and lower limbs due to lymphoedema. Podoconiosis has a curable pre-elephantiasic phase. However, once

Key role of symbiotic dinitrogen fixation in tropical forest secondary succession

DEFF Research Database (Denmark)

Batterman, Sarah A.; Hedin, Lars O.; Van Breugel, Michiel

2013-01-01

Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO 2 may be constrained by nitrogen, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N 2), but it is unclear whether this function...... tree species across the entire forest age sequence. These findings show that symbiotic N 2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO 2....

Measurements of the upper troposphere and lower stratosphere during tropical cyclones using the GPS radio occultation technique

DEFF Research Database (Denmark)

Biondi, Riccardo; Neubert, Torsten; Syndergaard, Stig

2011-01-01

and Climate (COSMIC) were analyzed, focusing on two particular tropical cyclones with completely different characteristics, the hurricane Bertha, which formed in the Atlantic Basin during July 2008 and reached a maximum intensity of Category 3, and the typhoon Hondo, which formed in the south Indian Ocean...... during 2008 reaching a maximum intensity of Category 4. The result is positive, suggesting that the bending angle of a GPS radio occultation signal contains interesting information on the atmosphere around the tropopause, but not any information regarding the water vapour. The maximum percentage anomaly...

Tropical intraseasonal rainfall variability in the CFSR

Energy Technology Data Exchange (ETDEWEB)

Wang, Jiande [I.M. System Group Inc. at NOAA/NCEP/EMC, Camp Springs, MD (United States); Wang, Wanqiu [NOAA/NCEP/CPC, Camp Springs, MD (United States); Fu, Xiouhua [University of Hawaii at Manoa, IPRC, SOEST, Honolulu, HI (United States); Seo, Kyong-Hwan [Pusan National University, Department of Atmospheric Sciences, Busan (Korea, Republic of)

2012-06-15

While large-scale circulation fields from atmospheric reanalyses have been widely used to study the tropical intraseasonal variability, rainfall variations from the reanalyses are less focused. Because of the sparseness of in situ observations available in the tropics and strong coupling between convection and large-scale circulation, the accuracy of tropical rainfall from the reanalyses not only measures the quality of reanalysis rainfall but is also to some extent indicative of the accuracy of the circulations fields. This study analyzes tropical intraseasonal rainfall variability in the recently completed NCEP Climate Forecast System Reanalysis (CFSR) and its comparison with the widely used NCEP/NCAR reanalysis (R1) and NCEP/DOE reanalysis (R2). The R1 produces too weak rainfall variability while the R2 generates too strong westward propagation. Compared with the R1 and R2, the CFSR produces greatly improved tropical intraseasonal rainfall variability with the dominance of eastward propagation and more realistic amplitude. An analysis of the relationship between rainfall and large-scale fields using composites based on Madden-Julian Oscillation (MJO) events shows that, in all three NCEP reanalyses, the moisture convergence leading the rainfall maximum is near the surface in the western Pacific but is above 925 hPa in the eastern Indian Ocean. However, the CFSR produces the strongest large-scale convergence and the rainfall from CFSR lags the column integrated precipitable water by 1 or 2 days while R1 and R2 rainfall tends to lead the respective precipitable water. Diabatic heating related to the MJO variability in the CFSR is analyzed and compared with that derived from large-scale fields. It is found that the amplitude of CFSR-produced total heating anomalies is smaller than that of the derived. Rainfall variability from the other two recently produced reanalyses, the ECMWF Re-Analysis Interim (ERAI), and the Modern Era Retrospective-analysis for Research and

Cellular metabolic rate is influenced by life-history traits in tropical and temperate birds.

Science.gov (United States)

Jimenez, Ana Gabriela; Van Brocklyn, James; Wortman, Matthew; Williams, Joseph B

2014-01-01

In general, tropical birds have a "slow pace of life," lower rates of whole-animal metabolism and higher survival rates, than temperate species. A fundamental challenge facing physiological ecologists is the understanding of how variation in life-history at the whole-organism level might be linked to cellular function. Because tropical birds have lower rates of whole-animal metabolism, we hypothesized that cells from tropical species would also have lower rates of cellular metabolism than cells from temperate species of similar body size and common phylogenetic history. We cultured primary dermal fibroblasts from 17 tropical and 17 temperate phylogenetically-paired species of birds in a common nutritive and thermal environment and then examined basal, uncoupled, and non-mitochondrial cellular O2 consumption (OCR), proton leak, and anaerobic glycolysis (extracellular acidification rates [ECAR]), using an XF24 Seahorse Analyzer. We found that multiple measures of metabolism in cells from tropical birds were significantly lower than their temperate counterparts. Basal and uncoupled cellular metabolism were 29% and 35% lower in cells from tropical birds, respectively, a decrease closely aligned with differences in whole-animal metabolism between tropical and temperate birds. Proton leak was significantly lower in cells from tropical birds compared with cells from temperate birds. Our results offer compelling evidence that whole-animal metabolism is linked to cellular respiration as a function of an animal's life-history evolution. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to have lower rates of metabolism than cells from shorter-lived temperate species.

Cellular metabolic rate is influenced by life-history traits in tropical and temperate birds.

Directory of Open Access Journals (Sweden)

Ana Gabriela Jimenez

Full Text Available In general, tropical birds have a "slow pace of life," lower rates of whole-animal metabolism and higher survival rates, than temperate species. A fundamental challenge facing physiological ecologists is the understanding of how variation in life-history at the whole-organism level might be linked to cellular function. Because tropical birds have lower rates of whole-animal metabolism, we hypothesized that cells from tropical species would also have lower rates of cellular metabolism than cells from temperate species of similar body size and common phylogenetic history. We cultured primary dermal fibroblasts from 17 tropical and 17 temperate phylogenetically-paired species of birds in a common nutritive and thermal environment and then examined basal, uncoupled, and non-mitochondrial cellular O2 consumption (OCR, proton leak, and anaerobic glycolysis (extracellular acidification rates [ECAR], using an XF24 Seahorse Analyzer. We found that multiple measures of metabolism in cells from tropical birds were significantly lower than their temperate counterparts. Basal and uncoupled cellular metabolism were 29% and 35% lower in cells from tropical birds, respectively, a decrease closely aligned with differences in whole-animal metabolism between tropical and temperate birds. Proton leak was significantly lower in cells from tropical birds compared with cells from temperate birds. Our results offer compelling evidence that whole-animal metabolism is linked to cellular respiration as a function of an animal's life-history evolution. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to have lower rates of metabolism than cells from shorter-lived temperate species.

Tropical New World Glacier Recession from the mid-1980s to the mid-2000s

Science.gov (United States)

Slayback, D. A.; Tucker, C. J.

2010-12-01

We report on the systematic retreat of all glaciers in the tropics of the New World from the mid-1980s to the mid-2000s. These glaciers comprise 99% of the world’s tropical glaciers and occur in Bolivia, Peru, Ecuador, Colombia, Venezuela, and Mexico. It was necessary to use a large quantity of Landsat satellite data (124 images), selecting multiple images for every glacier for both epochs, to minimize confusion of glacier area with snow. Change in glacier extent was combined with a digital elevation model (DEM) to provide information on the elevation and aspect of areas of glacier recession. Overall, we found glacier recession of approximately 30% over twenty years, declining from ~2500 km2 from the mid-1980s to ~1800 km2 in the mid-2000s. In addition, there was a strong association of glacier recession with elevation and aspect. We discuss these trends in relation to hypothesized climatic influences.

SELEX-Based Screening of Exosome-Tropic RNA.

Science.gov (United States)

Yamashita, Takuma; Shinotsuka, Haruka; Takahashi, Yuki; Kato, Kana; Nishikawa, Makiya; Takakura, Yoshinobu

2017-01-01

Cell-derived nanosized vesicles or exosomes are expected to become delivery carriers for functional RNAs, such as small interfering RNA (siRNA). A method to efficiently load functional RNAs into exosomes is required for the development of exosome-based delivery carriers of functional RNAs. However, there is no method to find exosome-tropic exogenous RNA sequences. In this study, we used a systematic evolution of ligands by exponential enrichment (SELEX) method to screen exosome-tropic RNAs that can be used to load functional RNAs into exosomes by conjugation. Pooled single stranded 80-base RNAs, each of which contains a randomized 40-base sequence, were transfected into B16-BL6 murine melanoma cells and exosomes were collected from the cells. RNAs extracted from the exosomes were subjected to next round of SELEX. Cloning and sequencing of RNAs in SELEX-screened RNA pools showed that 29 of 56 clones had a typical RNA sequence. The sequence found by SELEX was enriched in exosomes after transfection to B16-BL6 cells. The results show that the SELEX-based method can be used for screening of exosome-tropic RNAs.

Analysis of the interannual variability of tropical cyclones striking the California coast based on statistical downscaling

Science.gov (United States)

Mendez, F. J.; Rueda, A.; Barnard, P.; Mori, N.; Nakajo, S.; Espejo, A.; del Jesus, M.; Diez Sierra, J.; Cofino, A. S.; Camus, P.

2016-02-01

Hurricanes hitting California have a very low ocurrence probability due to typically cool ocean temperature and westward tracks. However, damages associated to these improbable events would be dramatic in Southern California and understanding the oceanographic and atmospheric drivers is of paramount importance for coastal risk management for present and future climates. A statistical analysis of the historical events is very difficult due to the limited resolution of atmospheric and oceanographic forcing data available. In this work, we propose a combination of: (a) statistical downscaling methods (Espejo et al, 2015); and (b) a synthetic stochastic tropical cyclone (TC) model (Nakajo et al, 2014). To build the statistical downscaling model, Y=f(X), we apply a combination of principal component analysis and the k-means classification algorithm to find representative patterns from a potential TC index derived from large-scale SST fields in Eastern Central Pacific (predictor X) and the associated tropical cyclone ocurrence (predictand Y). SST data comes from NOAA Extended Reconstructed SST V3b providing information from 1854 to 2013 on a 2.0 degree x 2.0 degree global grid. As data for the historical occurrence and paths of tropical cycloneas are scarce, we apply a stochastic TC model which is based on a Monte Carlo simulation of the joint distribution of track, minimum sea level pressure and translation speed of the historical events in the Eastern Central Pacific Ocean. Results will show the ability of the approach to explain seasonal-to-interannual variability of the predictor X, which is clearly related to El Niño Southern Oscillation. References Espejo, A., Méndez, F.J., Diez, J., Medina, R., Al-Yahyai, S. (2015) Seasonal probabilistic forecasting of tropical cyclone activity in the North Indian Ocean, Journal of Flood Risk Management, DOI: 10.1111/jfr3.12197 Nakajo, S., N. Mori, T. Yasuda, and H. Mase (2014) Global Stochastic Tropical Cyclone Model Based on

Diversity of Ammonia Oxidizing Archaea in Tropical Compost Systems

OpenAIRE

Vidya eDe Gannes; Gaius eEudoxie; David H Dyer; William James Hickey

2012-01-01

Composting is widely used to transform waste materials into valuable agricultural products. In the tropics, large quantities of agricultural wastes could be potentially useful in agriculture after composting. However, while microbiological processes of composts in general are well established, relatively little is known about microbial communities that may be unique to these in tropical systems, particularly nitrifiers. The recent discovery of ammonia oxidizing archaea (AOA) has changed the p...

Spatial δ18Osw-SSS relationship across the western tropical Pacific Ocean

Science.gov (United States)

Thompson, D. M.; Conroy, J. L.; Wyman, A.; Read, D.

2017-12-01

Dynamic hydroclimate processes across the western tropical Pacific lead to strong spatial and temporal variability in δ18Osw and sea-surface salinity (SSS) across the western Pacific. Corals in this region have therefore provided key information about past SSS variability, as δ18Osw contributes strongly to coral δ18O across this region. However, uncertainties in the δ18Osw-SSS relationship across space and time often limit quantitative SSS reconstructions from such coral records. Recent work demonstrates considerable variability in the δ18Osw-SSS relationship across the Pacific, which may lead to over- or under-estimation of the contribution of SSS to coral δ18O, particularly across the western tropical Pacific (Conroy et al. 2017). Here we assess the spatial δ18Osw-SSS relationship across the dynamic western tropical Pacific, capitalizing on a transit between Subic Bay, Philippines and Townsville, Australia aboard the International Ocean Discovery program's JOIDES Resolution. Water samples and weather conditions were collected 3 times daily (6:00, 12:00, 18:00) en route, resulting in a network of 47 samples spaced at semi-regular 130-260 km intervals across the western Pacific from 14°N to 18°S. The route also crossed near long-term δ18Osw monitoring sites at Papua New Guinea and Palau (Conroy et al. 2017), allowing us to compare the spatial and temporal δ18Osw-SSS relationships at these sites and test the space-for-time assumption. We present the δ18Osw-SSS relationship across this region, compare the relationship across space and time, and discuss the implications of our results for SSS reconstructions from coral δ18O.

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.

Weak leaf photosynthesis and nutrient content relationships from tropical vegetation

Science.gov (United States)

Domingues, T. F.; Ishida, F. Y.; Feldpaush, T.; Saiz, G.; Grace, J.; Meir, P.; Lloyd, J.

2015-12-01

Evergreen rain forests and savannas are the two major vegetations of tropical land ecosystems, in terms of land area, biomass, biodiversity, biogeochemical cycles and rates of land use change. Mechanistically understanding ecosystem functioning on such ecosystems is still far from complete, but important for generation of future vegetation scenarios in response to global changes. Leaf photosynthetic rates is a key processes usually represented on land surface-atmosphere models, although data from tropical ecosystems is scarce, considering the high biodiversity they contain. As a shortcut, models usually recur to relationships between leaf nutrient concentration and photosynthetic rates. Such strategy is convenient, given the possibility of global datasets on leave nutrients derived from hyperspectral remote sensing data. Given the importance of Nitrogen on enzyme composition, this nutrient is usually used to infer photosynthetic capacity of leaves. Our experience, based on individual measurements on 1809 individual leaves from 428 species of trees and shrubs naturally occurring on tropical forests and savannas from South America, Africa and Australia, indicates that the relationship between leaf nitrogen and its assimilation capacity is weak. Therefore, leaf Nitrogen alone is a poor predictor of photosynthetic rates of tropical vegetation. Phosphorus concentrations from tropical soils are usually low and is often implied that this nutrient limits primary productivity of tropical vegetation. Still, phosphorus (or other nutrients) did not exerted large influence over photosynthetic capacity, although potassium influenced vegetation structure and function. Such results draw attention to the risks of applying universal nitrogen-photosynthesis relationships on biogeochemical models. Moreover, our data suggests that affiliation of plant species within phylogenetic hierarchy is an important aspect in understanding leaf trait variation. The lack of a strong single

Diversity and host range of foliar fungal endophytes: are tropical leaves biodiversity hotspots?

Science.gov (United States)

Arnold, A Elizabeth; Lutzoni, F

2007-03-01

Fungal endophytes are found in asymptomatic photosynthetic tissues of all major lineages of land plants. The ubiquity of these cryptic symbionts is clear, but the scale of their diversity, host range, and geographic distributions are unknown. To explore the putative hyperdiversity of tropical leaf endophytes, we compared endophyte communities along a broad latitudinal gradient from the Canadian arctic to the lowland tropical forest of central Panama. Here, we use molecular sequence data from 1403 endophyte strains to show that endophytes increase in incidence, diversity, and host breadth from arctic to tropical sites. Endophyte communities from higher latitudes are characterized by relatively few species from many different classes of Ascomycota, whereas tropical endophyte assemblages are dominated by a small number of classes with a very large number of endophytic species. The most easily cultivated endophytes from tropical plants have wide host ranges, but communities are dominated by a large number of rare species whose host range is unclear. Even when only the most easily cultured species are considered, leaves of tropical trees represent hotspots of fungal species diversity, containing numerous species not yet recovered from other biomes. The challenge remains to recover and identify those elusive and rarely cultured taxa with narrower host ranges, and to elucidate the ecological roles of these little-known symbionts in tropical forests.

Copepoda endoparasitic of tropical holothurians

NARCIS (Netherlands)

Stock, Jan H.

1968-01-01

A number of Copepoda of the family Lichomolgidae, all endoparasitic in tropical holothurians, has been described. All belong to the group of genera related to Paranthessius, as borne out by the structure of their appendages, although the body-shape often has undergone modifications due to the

Ozone in the Tropical Troposphere

NARCIS (Netherlands)

Peters, Wouter

2002-01-01

The aim of the research presented here is to acquire knowledge of the past, present, and future composition, stability, sensitivity, and variability of the troposphere. We focus mostly on the tropical regions because it has received little attention so far, measurements here are scarce, and large

Colonial adventures in tropical agriculture

NARCIS (Netherlands)

Buelens, Frans; Frankema, Ewout

2016-01-01

How profitable were foreign investments in plantation agriculture in the Netherlands Indies during the late colonial era? We use a new dataset of monthly quoted stock prices and dividends of international companies at the Brussels stock exchange to estimate the returns to investment in tropical

Tracking ENSO with tropical trees: Progress in stable isotope dendroclimatology

Science.gov (United States)

Evans, M. N.; Poussart, P. F.; Saleska, S. R.; Schrag, D. P.

2002-12-01

The terrestrial tropics remain an important gap in the growing proxy network used to characterize past ENSO behavior. Here we describe a strategy for development of proxy estimates of paleo-ENSO, via proxy rainfall estimates derived from stable isotope (δ18O) measurements made on tropical trees. The approach applies a new model of oxygen isotopic composition of alpha-cellulose (Roden et al., 2000), a rapid method for cellulose extraction from raw wood (Brendel et al., 2000), and continuous flow isotope ratio mass spectrometry (Brand, 1996) to develop proxy chronological, rainfall and growth rate estimates from tropical trees, even those lacking annual rings. The promise and pitfalls of the approach are illustrated in pilot datasets from the US, Costa Rica, Brazil, and Peru, which show isotopic cycles of 4-6 per mil, and interannual anomalies of up to 8 per mil. Together with the mature ENSO proxies (corals, extratropical tree-rings, varved sediments, and ice cores), replicated and well-dated stable isotope chronologies from tropical trees may eventually improve our understanding of ENSO history over the past several hundred years.

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.

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...

Effects of subsurface ocean dynamics on instability waves in the tropical Pacific

Science.gov (United States)

Lawrence, Sean P.; Allen, Myles R.; Anderson, David L. T.; Llewellyn-Jones, David T.

1998-08-01

Tropical instability waves in a primitive equation model of the tropical Pacific Ocean, forced with analyzed wind stresses updated daily, show unexpectedly close phase correspondence with observation through the latter half of 1992. This suggests that these waves are not pure instabilities developing from infinitesimal disturbances, but that their phases and phase speeds are at least partially determined by the wind stress forcing. To quantify and explain this observation, we perfomed several numerical experiments, which indicate that remotely forced Rossby waves can influence both the phase and phase speed of tropical instability waves. We suggest that a remote wind forcing determines the high model/observation phase correspondence of tropical instability waves through a relatively realistic simulation of equatorial Kelvin and Rossby wave activity.

A concise biogas plant construction suitable for Ghana and other tropical countries

Energy Technology Data Exchange (ETDEWEB)

Gbagbo, J.K.N.

1997-04-01

This report is intended to be used by people in the field of biogas for workshops, technicians, teachers to educate as well as to carry out hands on constructions in Ghana and other tropical countries. Chapter 1, discusses the biogas technology, what a biogas plant is, and how it functions. Chapter 2, describes the entire process. Chapter 3, discusses the necessary conditions for fermentation. Chapter 4, the measuring parameters for monitoring the system. Chapter 5, describes the various types of biogas plants suitable for tropical countries. Chapter 6, describes a planning guide for Ghana and other tropical countries. Chapter 7, discusses digester sizing and finally, Chapter 8, describes a concise biogas plant construction suitable for the rural areas of Ghana and other tropical countries. (au)

Southern Ocean Convection and tropical telleconnections

Science.gov (United States)

Marinov, I.; Cabre, A.; Gnanadesikan, A.

2014-12-01

We show that Southern Ocean (SO) temperatures in the latest generation of Earth System Models exhibit two major modes of variation, one driven by deep convection, the other by tropical variability. We perform a CMIP5 model intercomparison to understand why different climate models represent SO variability so differently in long, control simulations. We show that multiyear variability in Southern Ocean sea surface temperatures (SSTs) can in turn influence oceanic and atmospheric conditions in the tropics on short (atmospheric) time-scales. We argue that the strength and pattern of SO-tropical teleconnections depends on the intensity of SO deep convection. Periodic convection in the SO is a feature of most CMIP5 models under preindustrial forcing (deLavergne et al., 2014). Models show a wide distribution in the spatial extent, periodicity and intensity of their SO convection, with some models convecting most of the time, and some showing very little convection. In a highly convective coupled model, we find that multidecadal variability in SO and global SSTs, as well as SO heat storage are driven by Weddell Sea convective variability, with convective decades relatively warm due to the heat released from the deep southern ocean and non-convective decades cold due to the subsurface storage of heat. Furthermore, pulses of SO convection drive SST and sea ice variations, influencing absorbed shortwave and emitted longwave radiation, wind, cloud and precipitation patterns, with climatic implications for the low latitudes via fast atmospheric teleconnections. We suggest that these high-low latitude teleconnection mechanisms are relevant for understanding hiatus decades. Additionally, Southern Ocean deep convection varied significantly during past, natural climate changes such as during the last deglaciation. Weddell Sea open convection was recently weakened, likely as a consequence of anthropogenic forcing and the resulting surface freshening. Our study opens up the

W Photoprotection in Tropical Marine Organisms

Science.gov (United States)

Armstrong, Roy A.

1997-01-01

Increasing levels of ultraviolet (UV) radiation reaching the earth's surface which results from stratospheric ozone depletions could have serious implications for terrestrial plants and for aquatic organisms within the euphotic zone. A documented 9% decline in ozone at mid-latitudes is considered to produce a 12% increase in harmful UV radiation. The biologically damaging effects of higher UV levels, particularly W-B (280-320 rim), could manifest earlier in the tropics because of the relative thinness of the earth's equatorial ozone layer. Tropical marine organisms are also living close to their upper tolerance levels of water temperature, However, despite the large potential effects on plants and animals, little is known about UV effects on tropical ecosystems. Long-term ecological studies are needed to quantify the effects of increased UV radiation on terrestrial and marine ecosystems and to produce reliable data for prediction. Plants have developed several mechanisms to protect themselves from harmful UV radiation, one of which is the production of secondary leaf pigments that absorb W-B radiation (screening pigments). A higher concentration of screening pigments (e.g. flavonoids) in leaves may be interpreted as a natural response to increased W radiation. If higher concentrations of flavonoids filter out the excessive W radiation, no damage will occur, as suggested by Caldwell et al. (1989) and Tevini (1993). Failure to screen all W-B may result in deleterious effects on photosynthesis, plant genetic material, and plant and leaf morphology and growth. Eventually this will have an impact on ecosystem processes, structure, species composition, and productivity. This paper describes an ongoing project that is assessing the responses of mangroves, seagrasses and corals to W radiation by studying pigment concentrations, biophysical parameters, and variations in spectral reflectance in the field and in W-reduction experiments. Preliminary results on the distribution

Tropical forest transitions: structural changes in forest area, composition and landscape

NARCIS (Netherlands)

Wiersum, K.F.

2014-01-01

Most studies on tropical forest dynamics focus on the processes of deforestation and forest degradation and its associated ecological impacts; comparatively little attention is given to the emergence of forest transitions. This review gives an overview of forest transitions in the tropics as

Polarimetric data for tropical forest monitoring : studies at the Colombian Amazon

NARCIS (Netherlands)

Quiñones Fernández, M.

2002-01-01

An urgent need exists for accurate data on the actual tropical forest extent, deforestation, forest structure, regeneration and diversity. The availability of accurate land cover maps and tropical forest type maps, and the possibility to update these maps frequently, is of

Commodity culture: tropical health and hygiene in the British Empire.

Science.gov (United States)

Johnson, Ryan

2008-06-01

Before heading to a 'tropical' region of the Empire, British men and women spent considerable time and effort gathering outfit believed essential for their impending trip. Ordinary items such as soap, clothing, foodstuffs and bedding became transformed into potentially life-saving items that required the fastidious attention of any would-be traveller. Everyone from scientists and physicians to missionaries and administrators was bombarded by relentless advertising and abundant advice about the outfit needed to preserve health in a tropical climate. A closer look at this marketing exercise reveals much about the way people thought about tropical people, places, health and hygiene and how scientific and commercial influences shaped this Imperial commodity culture.

Wind data collected by a fixed-wing aircraft in the vicinity of a tropical cyclone over the south China coastal waters

Energy Technology Data Exchange (ETDEWEB)

Chan, P.W.; Hon, K.K. [Hong Kong Observatory, Kowloon, HK (China); Foster, S. [Aventech Research Inc., Ontario (Canada)

2011-06-15

The fixed-wing aircraft of Government Flying Service of the Hong Kong Government has recently equipped with an upgraded meteorological measuring system. This system provides horizontal wind velocity components up to 90 m/s at an accuracy of 0.5 m/s for straight and level flight. Besides search and rescue (SAR) missions, this aircraft is also used for windshear and turbulence investigation flights at the Hong Kong International Airport. In a SAR operation in July 2009, the aircraft flew close to the eye of tropical cyclone Molave, when it was located at about 200 km to the east of Hong Kong over the south China coastal waters. The aircraft provided valuable information about the winds in association with Molave because aircraft reconnaissance for tropical cyclones is not carried out for South China Sea. Based on the aircraft measurements, the 1-second mean wind reached the maximum value of 88 knots at a height of 200 m above mean sea level. Assuming a power law with altitude with an exponent of 0.11 over open waters, the corresponding 1-second mean wind at a height of 10 m would be about 63 knots. The maximum 10-minute mean wind reached 69 knots with an average height of 260 m above mean sea level. The corresponding mean at 10 m would be about 48 knots. As such, based on the aircraft measurements (in which the aircraft might not fly into the areas of maximum winds associated with the tropical cyclone), Molave had at least a strength of tropical storm to severe tropical storm at the times of the measurements. Nowadays, the determination of the intensity of tropical cyclones over the South China Sea is normally based on remote sensing data only (e.g. radar and satellite observations). To the knowledge of the authors, the results presented in the paper are the first time that direct measurements of the winds near the centre of a tropical cyclone over the northern part of the South China Sea are made with an aircraft. Apart from the mean wind and gust, other properties

Amazonian Dark Earths: pathways to sustainable development in tropical rainforests?

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