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2.
Water Res ; 177: 115787, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32315899

RESUMO

Space exploration is demanding longer lasting human missions and water resupply from Earth will become increasingly unrealistic. In a near future, the spacecraft water monitoring systems will require technological advances to promptly identify and counteract contingent events of waterborne microbial contamination, posing health risks to astronauts with lowered immune responsiveness. The search for bio-analytical approaches, alternative to those applied on Earth by cultivation-dependent methods, is pushed by the compelling need to limit waste disposal and avoid microbial regrowth from analytical carryovers. Prospective technologies will be selected only if first validated in a flight-like environment, by following basic principles, advantages, and limitations beyond their current applications on Earth. Starting from the water monitoring activities applied on the International Space Station, we provide a critical overview of the nucleic acid amplification-based approaches (i.e., loop-mediated isothermal amplification, quantitative PCR, and high-throughput sequencing) and early-warning methods for total microbial load assessments (i.e., ATP-metry, flow cytometry), already used at a high readiness level aboard crewed space vehicles. Our findings suggest that the forthcoming space applications of mature technologies will be necessarily bounded by a compromise between analytical performances (e.g., speed to results, identification depth, reproducibility, multiparametricity) and detrimental technical requirements (e.g., reagent usage, waste production, operator skills, crew time). As space exploration progresses toward extended missions to Moon and Mars, miniaturized systems that also minimize crew involvement in their end-to-end operation are likely applicable on the long-term and suitable for the in-flight water and microbiological research.


Assuntos
Voo Espacial , Água , Humanos , Estudos Prospectivos , Reprodutibilidade dos Testes , Astronave
3.
PLoS One ; 15(2): e0227152, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32074104

RESUMO

The opportunistic pathogens Burkholderia cepacia and Burkholderia contaminans, both genomovars of the Burkholderia cepacia complex (BCC), are frequently cultured from the potable water dispenser (PWD) of the International Space Station (ISS). Here, we sequenced the genomes and conducted phenotypic assays to characterize these Burkholderia isolates. All recovered isolates of the two species fall within monophyletic clades based on phylogenomic trees of conserved single-copy core genes. Within species, the ISS-derived isolates all demonstrate greater than 99% average nucleotide identity (with 95-99% of genomes aligning) and share around 90% of the identified gene clusters from a pangenomic analysis-suggesting that the two groups are each composed of highly similar genomic lineages and their members may have all stemmed from the same two founding populations. The differences that can be observed between the recovered isolates at the pangenomic level are primarily located within putative plasmids. Phenotypically, macrophage intracellularization and lysis occurred at generally similar rates between all ISS-derived isolates, as well as with their respective type-terrestrial strain references. All ISS-derived isolates exhibited antibiotic sensitivity similar to that of the terrestrial reference strains, and minimal differences between isolates were observed. With a few exceptions, biofilm formation rates were generally consistent across each species. And lastly, though isolation date does not necessarily provide any insight into how long a given isolate had been aboard the ISS, none of the assayed physiology correlated with either date of isolation or distances based on nucleotide variation. Overall, we find that while the populations of Burkholderia present in the ISS PWS each maintain virulence, they are likely are not more virulent than those that might be encountered on planet and remain susceptible to clinically used antibiotics.


Assuntos
Infecções por Burkholderia/microbiologia , Burkholderia cepacia , Burkholderia , Água Potável/microbiologia , Filogenia , Astronave , Burkholderia/classificação , Burkholderia/isolamento & purificação , Burkholderia/patogenicidade , Burkholderia cepacia/classificação , Burkholderia cepacia/isolamento & purificação , Burkholderia cepacia/patogenicidade , Virulência
4.
Genes (Basel) ; 11(1)2020 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-31936690

RESUMO

The MinION sequencer has made in situ sequencing feasible in remote locations. Following our initial demonstration of its high performance off planet with Earth-prepared samples, we developed and tested an end-to-end, sample-to-sequencer process that could be conducted entirely aboard the International Space Station (ISS). Initial experiments demonstrated the process with a microbial mock community standard. The DNA was successfully amplified, primers were degraded, and libraries prepared and sequenced. The median percent identities for both datasets were 84%, as assessed from alignment of the mock community. The ability to correctly identify the organisms in the mock community standard was comparable for the sequencing data obtained in flight and on the ground. To validate the process on microbes collected from and cultured aboard the ISS, bacterial cells were selected from a NASA Environmental Health Systems Surface Sample Kit contact slide. The locations of bacterial colonies chosen for identification were labeled, and a small number of cells were directly added as input into the sequencing workflow. Prepared DNA was sequenced, and the data were downlinked to Earth. Return of the contact slide to the ground allowed for standard laboratory processing for bacterial identification. The identifications obtained aboard the ISS, Staphylococcus hominis and Staphylococcus capitis, matched those determined on the ground down to the species level. This marks the first ever identification of microbes entirely off Earth, and this validated process could be used for in-flight microbial identification, diagnosis of infectious disease in a crewmember, and as a research platform for investigators around the world.


Assuntos
Sequenciamento por Nanoporos/métodos , RNA Ribossômico 16S/genética , Manejo de Espécimes/métodos , Bactérias/genética , DNA Bacteriano/genética , DNA Ribossômico/genética , Exobiologia/métodos , Meio Ambiente Extraterreno , Genoma Bacteriano/genética , Microbiota/genética , Nanoporos , Análise de Sequência de DNA/métodos , Astronave/instrumentação
5.
PLoS Pathog ; 16(1): e1008153, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31999804

RESUMO

Human space travel is on the verge of visiting Mars and, in the future, even more distant places in the solar system. These journeys will be also made by terrestrial microorganisms (hitchhiking on the bodies of astronauts or on scientific instruments) that, upon arrival, will come into contact with new planetary environments, despite the best measures to prevent contamination. These microorganisms could potentially adapt and grow in the new environments and subsequently recolonize and infect astronauts. An even more challenging situation would be if truly alien microorganisms will be present on these solar system bodies: What will be their pathogenic potential, and how would our immune host defenses react? It will be crucial to anticipate these situations and investigate how the immune system of humans might cope with modified terrestrial or alien microbes. We propose several scenarios that may be encountered and how to respond to these challenges.


Assuntos
Equipamentos e Provisões/microbiologia , Interações Hospedeiro-Patógeno , Sistema Imunitário/imunologia , Astronautas , Exobiologia , Meio Ambiente Extraterreno , Humanos , Voo Espacial , Astronave
6.
Int J Syst Evol Microbiol ; 70(1): 71-76, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31622233

RESUMO

Two Gram-stain-positive, motile, endospore-forming, aerobic strains, designated V44-8T and V47-23aT, were isolated from environmental air sampling at the vehicle assembly building at Cape Canaveral, Florida, where the Viking spacecraft were assembled. Growth was observed at pH 7-9 (optimum, pH 9) for strain V44-8T, and pH 5-10 (pH 9) for strain V47-23aT. Both strains displayed growth in 0-5 % NaCl with an optimum at 1 % for strain V44-8T; 0 % for strain V47-23aT. Strains V44-8T and V47-23aT grew optimally at 32 °C, (15-32 °C) and 25 °C (20-45 °C), respectively. The cell wall of both strains contained meso-diaminopimelic acid as the diagnostic diamino acid. Both strains contained phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. The predominant cellular fatty acids were anteiso-C15 : 0, iso-C14 : 0 and iso-C15 : 0. Strain V47.23aT shared its highest 16S rRNA sequence similarity with Bacillus cavernae DSM-105484T at 96.9%, and V44.8T with Bacillus zeae DSM-103964T at 96.6 %. Based on their phenotypic characteristics and phylogenetic position inferred from 16S rRNA gene sequence analyses, the isolates were identified as being a members of the genus Bacillus that forms a separate clade when compared to close relatives. Average nucleotide identity and average amino acid identity values between strains V44-8T and DSM-103964T were 72.1% and 67.5 %; V47-23aT and DSM-105484T were 62.4% and 69.1%, respectively. Based on the phenotypic, genomic and biochemical data, strains V44-8T and V47-23aT represent two novel species in the genus Bacillus for which the names Bacillus glennii sp. nov. [type strain, V44-8T (=ATCC BAA-2860T =DSM 105192T)], and Bacillus saganii sp. nov. [V47-23aT (=ATCC BAA-2861T=DSM 105190T)] are proposed.


Assuntos
Microbiologia do Ar , Bacillus/classificação , Filogenia , Astronave , Bacillus/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Parede Celular/química , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ambiente Controlado , Ácidos Graxos/química , Florida , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
7.
Mar Pollut Bull ; 150: 110644, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31733903

RESUMO

As oil production worldwide continues to increase, particularly in the Gulf of Mexico, marine oil spill preparedness relies on deeper understanding of surface oil spill transport science. This paper describes experiments carried out on a chronic release of crude oil and aims to understand the residence time of oil slicks using a combination of remote sensing platforms and GPS tracked drifters. From April 2017 to August 2018, we performed multiple synchronized deployments of drogued and un-drogued drifters to monitor the life time (residence time) of the surface oil slicks originated from the MC20 spill site, located close to the Mississippi Delta. The hydrodynamic design of the two types of drifters allowed us to compare their performance differences. We found the un-drogued drifter to be more appropriate to measure the speed of oil transport. Drifter deployments under various wind conditions show that stronger winds lead to reduce the length of the slick, presumably because of an increase in the evaporation rate and entrainment of oil in the water produced by wave action. We have calculated the residence time of oil slicks at MC20 site to be between 4 and 28 h, with average wind amplitude between 3.8 and 8.8 m/s. These results demonstrate an inverse linear relationship between wind strength and residence time of the oil, and the average residence time of the oil from MC20 is 14.9 h.


Assuntos
Monitoramento Ambiental/métodos , Poluição por Petróleo , Petróleo/análise , Poluentes Químicos da Água/análise , Sistemas de Informação Geográfica , Golfo do México , Mississippi , Tecnologia de Sensoriamento Remoto , Astronave , Vento
8.
Chemosphere ; 239: 124678, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494323

RESUMO

In the developing countries such as China, most well-developed areas have suffered severe haze pollution, which was associated with increased premature morbidity and mortality and attracted widespread public concerns. Since ground-based PM2.5 monitoring has limited temporal and spatial coverage, satellite aerosol remote sensing data has been increasingly applied to map large-scale PM2.5 characteristics through advanced spatial statistical models. Although most existing research has taken advantage of the polar orbiting satellite instruments, a major limitation of the polar orbiting platform is its limited sampling frequency (e.g., 1-2 times/day), which is insufficient for capturing the PM2.5 variability during short but intense heavy haze episodes. As the first attempt, we quantitatively investigated the feasibility of using the aerosol optical depth (AOD) data retrieved by the Geostationary Ocean Color Imager (GOCI) to estimate hourly PM2.5 concentrations during winter haze episodes in the Yangtze River Delta (YRD). We developed a three-stage spatial statistical model, using GOCI AOD and fine mode fraction, as well as corresponding monitoring PM2.5 concentrations, meteorological and land use data on a 6-km modeling grid with complete coverage in time and space. The 10-fold cross-validation R2 was 0.72 with a regression slope of 1.01 between observed and predicted hourly PM2.5 concentrations. After gap filling, the R2 value for the three-stage model was 0.68. We further analyzed two representative large regional episodes, i.e., a "multi-process diffusion episode" during December 21-26, 2015 and a "Chinese New Year episode" during February 7-8, 2016. We concluded that AOD retrieved by geostationary satellites could serve as a new valuable data source for analyzing the heavy air pollution episodes.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Tecnologia de Sensoriamento Remoto/métodos , Aerossóis/análise , China , Meteorologia , Modelos Estatísticos , Rios , Estações do Ano , Astronave
9.
Zoolog Sci ; 36(6): 490-503, 2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31833320

RESUMO

Understanding migration ecology of Eurasian wigeons (Mareca penelope) is crucial for effective population management, mitigating conflicts with human, and habitat conservation. The objectives of the present study were 1) to determine their migration patterns of Eurasian wigeons in the East Asian flyway, and 2) to identify the key breeding and stopover sites. From 2007 to 2016, a total of the 64 wigeons, which wintered in Japan, were equipped with satellite transmitters. Most Eurasian wigeons migrated to breeding sites in Russia either (a) via a continental route through China, (b) via the Kamchatka Peninsula, or (c) via Sakhalin Island. In spring, many of the Eurasian wigeons (60.98%) migrated via the continental route. In autumn, most Eurasian wigeons (57.14%) migrated through Kamchatka. These differences may be attributable to the influence of Okhotsk Sea air mass on migration decisions due to loop migration. Similarly to the migration of Mallards, Eurasian wigeons employed a "long-stay and short-travel" migration strategy. Eurasian wigeons mainly nested between latitude between 43° to 75°N. From the present findings and the published literature, Eurasian wigeons that winter in Japan are considered to migrate to Russia, China, and the United States during the breeding season, although the main breeding area is in northeastern Russia. A total of 296 important sites to Eurasian wigeons were mapped, and 118 location names with geographic coordinates, and the top five most frequently used sites were identified in each season.


Assuntos
Sistemas de Identificação Animal , Migração Animal , Anseriformes/fisiologia , Estações do Ano , Astronave , Animais , China , Japão , Federação Russa
11.
J Biosci ; 44(5)2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31719234

RESUMO

The International Space Station (ISS) is a confined and closed habitat with unique conditions such as cosmic radiation, and microgravity. These conditions have a strong effect on the human and spacecraft microflora. They can affect the immune response of the crew-members, thus posing a threat to their health. Microbial diversity and abundance of microorganisms from surfaces, air filters and air samples on the ISS have been studied. Enterobacteriaceae, Bacillus spp., Propionibacterium spp., Corynebacterium spp., and Staphylococcus spp. were among the most frequently isolated bacteria. Microbial growth, biofilm formation, stress response, and pathogenicity are affected by microgravity. Increased resistance to antibiotics in bacteria isolated from the ISS has often been reported. Enterococcus faecalis and Staphylococcus spp. isolates from the ISS have been shown to harbor plasmid-encoded transfer genes. These genes facilitate the dissemination of antibiotic resistances. These features of ISS-pathogens call for novel approaches including highly effective antimicrobials which can be easily used on the ISS. A promising material is the antimicrobial surface coating AGXX, a self-recycling material consisting of two noble metals. It drastically reduced microbial growth of multi-resistant human pathogens, such as staphylococci and enterococci. Further novel approaches include the application of cold atmospheric plasma for the sterilization of spacecrafts.


Assuntos
Archaea/patogenicidade , Bactérias/patogenicidade , Biofilmes , Astronave , Archaea/isolamento & purificação , Bactérias/isolamento & purificação , Especificidade da Espécie
12.
Proc Jpn Acad Ser B Phys Biol Sci ; 95(9): 495-522, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31708495

RESUMO

Since the new era of infrared astronomy was opened by the Two Micron Sky Survey by Neugebauer et al. in the early 1960s, about a half century has passed. During this time, observations have expanded rapidly and widely, to almost every field of astronomy, to reveal new perspectives on the universe. As a result, infrared astronomy has become one of the major branches of astronomy, along with optical, radio, X-ray as well as high-energy particle astronomy. In Japan, we started our infrared astronomical activities at a rather early time, under relatively poor technical and environmental conditions, and using somewhat unconventional methods to overcome these difficulties. Here, a brief survey is presented of developments concerning infrared astronomy during the past half century, while mainly recollecting our footprints in the stream of world activities.


Assuntos
Fenômenos Astronômicos , Astronomia/métodos , Astronomia/tendências , Humanos , Raios Infravermelhos , Japão , Dispositivos Ópticos , Astronave , Telescópios
13.
PLoS One ; 14(11): e0224478, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31714917

RESUMO

Interferences and accuracy problem are one of the most talked issues in today's world for sensor technology. To deal with this contention, a microstrip framework consisting of a dual mode double negative (DNG) metamaterial based bandpass filter is presented in this article. To obtain the ultimate noise reduction bandpass filter, the proposed structure has to go through a series of development process, where the characteristics of the structure are tested to the limit. This filter is built on Rogers RT-5880 substrate with a 50Ω microstrip line. To pursue the elementary mode of resonant frequency, the ground layer of the structure is kept partially filled and a gradual analysis is executed on the prospective metamaterial (resonator) unit cell. Depending on the developed unit cell, the filter is constructed and fabricated to verify the concept, concentrating on GPS (1.55GHz), Earth Exploration-Satellite (2.70GHz) and WiMAX (3.60GHz) bands of frequencies. Moreover, the structure is investigated using Nicolson-Ross-Weir (NRW) approach to justify the metamaterial characteristics, and also tested on S-parameters, current distribution, electric and magnetic fields and quality factor. Having a propitious architecture and DNG characteristics, the proposed structure is suitable for bandpass filter for GPS, Earth Exploration-Satellite and WiMAX frequency sensing applications.


Assuntos
Desenho de Equipamento , Sistemas de Informação Geográfica , Astronave , Impedância Elétrica , Eletrônica
14.
Environ Pollut ; 255(Pt 2): 113267, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31574391

RESUMO

In recent years, ozone pollution has become more and more serious in China. Several epidemiological studies have demonstrated the correlation between short-term ozone exposure and several health risks including all-cause mortality, cardiovascular mortality, and respiratory mortality. In this study, the daily ozone exposure levels with 10 km × 10 km resolution were estimated based on satellite data derived from Ozone Monitoring Instrument (OMI) and the monitoring data. The health impacts for potential decrease in the daily ozone concentration and the corresponding economic benefits in 2016 were estimated by applying the environmental Benefits Mapping and Analysis Program-Community Edition (BenMAP-CE) model. By reducing the daily maximum 8-h average concentration of ozone to 100 µg/m3, the estimated avoided all-cause mortalities were 120 × 103 (95% confidence interval (CI): 67 × 103, 160 × 103) cases and the correspondingly economic benefits ranged from 36 to 64 billion CNY using amended human capital (AHC) and willingness to pay (WTP) method in 2016. If the daily maximum 8-h average concentration of ozone were rolled back to 70 µg/m3, the estimated avoided all-cause mortalities were 160 × 103 (95% CI: 98 × 103, 230 × 103) cases and economic benefits ranged from 54 to 95 billion CNY based on AHC and WTP methods.


Assuntos
Poluição do Ar/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Tecnologia de Sensoriamento Remoto , Poluentes Atmosféricos/análise , Poluição do Ar/análise , China , Exposição Ambiental/análise , Humanos , Modelos Teóricos , Ozônio/análise , Astronave
15.
Environ Pollut ; 255(Pt 1): 113106, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31541826

RESUMO

Satellite observations for regional air quality assessment rely on comprehensive spatial coverage, and daily monitoring with reliable, cloud-free data quality. We investigated spatiotemporal variation and data quality of two global satellite Aerosol Optical Depth (AOD) products derived from MODIS and VIIRS imagery. AOD is considered an essential atmospheric parameter strongly related to ground Particulate Matter (PM) in Southeast Asia (SEA). We analyze seasonal variation, urban/rural area influence, and biomass burning effects on atmospheric pollution. Validation indicated a strong relationship between AERONET ground AOD and both MODIS AOD (R2 = 0.81) and VIIRS AOD (R2 = 0.68). The monthly variation of satellite AOD and AERONET AOD reflects two seasonal trends of air quality separately for mainland countries including Myanmar, Laos, Cambodia, Thailand, Vietnam, and Taiwan, Hong Kong, and for maritime countries consisting of Indonesia, Philippines, Malaysia, Brunei, Singapore, and Timor Leste. The mainland SEA has a pattern of monthly AOD variation in which AODs peak in March/April, decreasing during wet season from May-September, and increasing to the second peak in October. However, in maritime SEA, AOD concentration peaks in October. The three countries with the highest annual satellite AODs are Singapore, Hong Kong, and Vietnam. High urban population proportions in Singapore (40.7%) and Hong Kong (21.6%) were associated with high AOD concentrations as expected. AOD values in SEA urban areas were a factor of 1.4 higher than in rural areas, with respective averages of 0.477 and 0.336. The AOD values varied proportionately to the frequency of biomass burning in which both active fires and AOD peak in March/April and September/October. Peak AOD in September/October in some countries could be related to pollutant transport of Indonesia forest fires. This study analyzed satellite aerosol product quality in relation to AERONET in SEA countries and highlighted framework of air quality assessment over a large, complicated region.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Análise Espaço-Temporal , Poluição do Ar/análise , Ásia Sudeste , Biomassa , Fogo , Estações do Ano , Astronave , Urbanização , Incêndios Florestais
16.
PLoS One ; 14(9): e0221551, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31490966

RESUMO

With the development and universal application of satellite technology, an important way to expand the function of satellites is setting up inter-satellite networks to make them work together. Traditional satellite networking methods generally adopt a fixed time slot allocation method, which is not suitable for small satellite groups with low latency and high throughput requirements. In order to solve this problem, it has been proposed to apply the traditional Wifi protocol in satellite networking. As there are differences between satellite networks and terrestrial networks, it's necessary to improve the traditional 802.11 protocol. The Media Access Control (MAC) protocol in 802.11 is improved in this paper, which mainly includes the adaptive algorithm of maximum contention window size and the growth algorithm of Contention Window (CW) size. The maximum contention window is adjusted according to the conflict state of the current network, which makes the network accommodate more satellite nodes. The CW growth algorithm improves the traditional Binary Exponential Back-off (BEB) algorithm, where the CW is designed according to the priority of the data frame or the network load. In this way, high-priority satellite accusation information will have higher reliability or tolerate greater network load.


Assuntos
Redes de Comunicação de Computadores , Astronave , Tecnologia sem Fio , Algoritmos
17.
PLoS One ; 14(9): e0222133, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31509556

RESUMO

High-Throughput Satellites (HTS) are a distinctive class of communication satellites that provide significantly more throughput per allocated bandwidth than traditional wide-beam communication satellites. They are the proverbial wave of creative disruption in the space industry and are poised to disrupt the communication market in significant ways. The objective of this work is to develop a decision-analytic framework for assessing the value of High-Throughput Satellites and to provide meaningful results of the value of such systems under realistic design, operational, and market conditions. We develop the cost and revenue models of HTS. To build the revenue model, we develop a hybrid data-driven and scenario-based load factor model that combines historical data based on financial records from current HTS operators with extrapolations based on best-, nominal-, and worst-case scenarios. We then integrate the cost and revenue models within a stochastic simulation environment and perform Monte-Carlo analysis of the net present value (NPV) of HTS. One important result is that a medium-sized HTS significantly outperforms a roughly equivalent traditional wide-beam satellite, even under the worst-case loading scenario. Another important result, here identified and quantified, is the tradeoff between the average revenue per user (ARPU) and average loading of the satellite and how it is mediated by the downlink speed provided to consumers. This result can be used in different ways, for example, by helping define the boundaries of what is competitively achievable in terms of ARPU and downlink speed offerings. The implications of these results are that they delineate the pathways to financial failure and the boundaries beyond which an HTS will be value-negative, or alternatively, the asymptotic minimum values for an HTS to be value-positive.


Assuntos
Astronave/classificação , Astronave/economia , Tomada de Decisões , Investimentos em Saúde , Modelos Econômicos , Método de Monte Carlo
18.
PLoS One ; 14(8): e0205862, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31461452

RESUMO

Translocated saltwater crocodiles (Crocodylus porosus) in the Northern Territory (NT) of Australia often return to their original capture sites, which complicates management interventions aimed at reducing human-crocodile conflict. We examined the spatial events implicated in this homing ability, using ARGOS satellite tracking devices. Five large male C. porosus (3.03 m to 4.02 m TL) were shifted and released 100-320 km from their capture sites, and 3 additional ones (3.67 m to 4.23 m TL) were released at their site of capture as controls. Translocated crocodiles were more mobile than the controls, and moved at sea in the direction of their original capture site. However, they were unable or unwilling to swim around a geographic structure, Cobourg Peninsula, which prevented homing being achieved in all five cases. Two control crocodiles remained near their capture sites, but one, after the first year, made a 900km journey for six months, before returning to its original capture and release site. Genetic analysis of tissue samples from nests across the NT coast demonstrated significant genetic structure across the coast, and confirmed that Cobourg Peninsula contributes to genetic differentiation among populations along the NT coast. These results provide new insights into C. porosus movements, which have management significance for the maintenance of public safety.


Assuntos
Jacarés e Crocodilos/genética , Jacarés e Crocodilos/fisiologia , Distribuição Animal , Geografia , Comportamento de Retorno ao Território Vital , Movimento , Animais , Estruturas Genéticas , Masculino , Astronave
19.
Mar Pollut Bull ; 146: 683-695, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31426210

RESUMO

The Eastern Arabian Sea (EAS) is affected by oil pollution, as often evidenced by the presence of tarballs along the West Coast of India (WCI). Tarball samples collected during May 2017 along the Goa coast were subject to biomarker fingerprints, and the results matched with Bombay High (BH) oil fingerprints. The present study primarily aims at identifying the potential minor spill areas using Sentinel-imagery. Interestingly, repeated occurrence of oil spills detected at two locations, perfectly matched with BH platforms. The simulated Lagrangian trajectories also depict that tarball particles have originated from those detected locations. In 2017 alone, the quantity of spilled oil was estimated to be 129,392 l. However, spills detected offshore regions of Kachchh and Mangalore were found to be caused by ships. This is the first comprehensive study, tracking the oil pollution sources in the EAS through multi-technique approach - chemical, remote sensing and numerical modeling.


Assuntos
Monitoramento Ambiental/métodos , Poluição por Petróleo/análise , Poluição Química da Água/análise , Índia , Petróleo/análise , Tecnologia de Sensoriamento Remoto/métodos , Navios , Astronave , Triterpenos/análise , Poluentes Químicos da Água/análise
20.
Aerosp Med Hum Perform ; 90(9): 807-812, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31426897

RESUMO

INTRODUCTION: The previous Spacecraft Maximal Allowable Concentrations (SMACs) for methanol were established by characterizing minor effects upon cognitive functions as a no-observable adverse effects level (NOAEL). However, an increasing awareness of the risk posed by Space-Associated Neuro-ocular Syndrome (SANS) has caused NASA Toxicology to reexamine SMACs for methanol because exposure to it can also adversely affect ocular health. An updated review of the literature indicates that no adjustments to the SMACs due to SANS complications were required, while confirming that effects upon the central nervous system remain the appropriate basis for the SMACs for methanol. Our review, however, identified several issues that provide justification for modest SMAC reductions. It has recently been recognized that inhaled methanol may reach the brain via the olfactory system and be absorbed there into the highly toxic metabolite formaldehyde. A benchmark dose (BMD) for an extra risk of 10%, derived from an analysis of the incidences of neurological lesions in monkeys chronically exposed to methanol, is an order of magnitude less than the Environmental Protection Agency's (EPA's) reference concentration for chronic inhalation of methanol. Reports calling attention to the relative insensitivity of traditional methods of assessing cognitive function erode confidence that adverse effects at the concentration reported as a NOAEL would have been recognizable. Therefore, an additional modest safety factor of three is applied to SMACs for methanol.Scully RR, Garcia H, McCoy JT, Ryder VE. Revisions to limits for methanol in the air of spacecraft. Aerosp Med Hum Perform. 2019; 90(9):807-812.


Assuntos
Cognição/efeitos dos fármacos , Metanol/toxicidade , Síndromes Neurotóxicas/prevenção & controle , Astronave/normas , Níveis Máximos Permitidos , Animais , Astronautas , Modelos Animais de Doenças , Haplorrinos , Humanos , Incidência , Concentração Máxima Permitida , Síndromes Neurotóxicas/epidemiologia , Síndromes Neurotóxicas/etiologia , Nível de Efeito Adverso não Observado , Exposição Ocupacional/normas , Testes de Toxicidade Crônica
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