Landsat analysis of the dynamics of the Chesapeake Bay plume on the continental shelf

The dynamics of the Chesapeake Bay plume have been studied by examination of 81 dates of Landsat images with color additive enhancement and single-band density slicing. The plume was interpreted from surface turbidity discontinuties as revealed in images from multispectral scanner (MSS) bands 4-7. Results show that the Chesapeake Bay plume usually frequents the Virginia coast south of the Bay mouth. Wind and tide vectors are the principal variables affecting the plume dynamics. Southwestern (compared to northern) winds spread and disperse the plume easterly over a large area. Ebb tide images (compared to flood tide images) show a more dispersed plume. Flooding waters produce high turbidity levels over the shallow northern portion of the Bay mouth

ANALYSIS OF HUMAN VERSUS MACHINE TRANSLATION ACCURACY

The purpose of this study was to determine whether significant differences exist in Chinese-to-English translation accuracy between moderate to higher-level human translators and commonly employed freely available machine translation tools. A Chinese-to-English language proficiency structure test and a Chinese-to-English phrase and sentence translation test were given to a large sample of machine (n=10) and human translators (n=133) who are native Chinese speakers with at least 15 years of familiarity with the English language. Results demonstrated that native Chinese speakers with this minimum level of English proficiency were significantly better at translating sentences and phrases from Chinese to English, compared to the ten freely available online machine translation applications, which unexpectedly showed a considerable degree of variation in translation accuracy among them. These results indicate that humans with at least a moderate level of exposure to a non-native language make far fewer translation errors compared to machine translation tools. This outcome is understandable, given the unique human ability to take into account subtle linguistic variants, context, and capricious meaning associated with the language and culture of different groups

Chesapeake Bay Plume Dynamics from LANDSAT

Examination of 81 dates of Landsat images with enhancement and density slicing has shown that the Chesapeake Bay plume usually frequents the Virginia coast south of the Bay mouth. Southwestern (compared to northern) winds spread the plume easterly over a large area. Ebb tide images (compared to flood tide images) show a more dispersed plume. Flooding waters produce high turbidity levels over the shallow northern portion of the Bay mouth.https://scholarworks.wm.edu/vimsbooks/1129/thumbnail.jp

Partial and impartial criticism in the major literary periodicals, 1800-30.

SIGLEAvailable from British Library Document Supply Centre- DSC:D40769/82 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Morpheus: Advancing Technologies for Human Exploration

NASA's Morpheus Project has developed and tested a prototype planetary lander capable of vertical takeoff and landing. Designed to serve as a vertical testbed (VTB) for advanced spacecraft technologies, the vehicle provides a platform for bringing technologies from the laboratory into an integrated flight system at relatively low cost. This allows individual technologies to mature into capabilities that can be incorporated into human exploration missions. The Morpheus vehicle is propelled by a LOX/Methane engine and sized to carry a payload of 1100 lb to the lunar surface. In addition to VTB vehicles, the Project s major elements include ground support systems and an operations facility. Initial testing will demonstrate technologies used to perform autonomous hazard avoidance and precision landing on a lunar or other planetary surface. The Morpheus vehicle successfully performed a set of integrated vehicle test flights including hot-fire and tethered hover tests, leading up to un-tethered free-flights. The initial phase of this development and testing campaign is being conducted on-site at the Johnson Space Center (JSC), with the first fully integrated vehicle firing its engine less than one year after project initiation. Designed, developed, manufactured and operated in-house by engineers at JSC, the Morpheus Project represents an unprecedented departure from recent NASA programs that traditionally require longer, more expensive development lifecycles and testing at remote, dedicated testing facilities. Morpheus testing includes three major types of integrated tests. A hot-fire (HF) is a static vehicle test of the LOX/Methane propulsion system. Tether tests (TT) have the vehicle suspended above the ground using a crane, which allows testing of the propulsion and integrated Guidance, Navigation, and Control (GN&C) in hovering flight without the risk of a vehicle departure or crash. Morpheus free-flights (FF) test the complete Morpheus system without the additional safeguards provided during tether. A variety of free-flight trajectories are planned to incrementally build up to a fully functional Morpheus lander capable of flying planetary landing trajectories. In FY12, these tests will culminate with autonomous flights simulating a 1 km lunar approach trajectory, hazard avoidance maneuvers and precision landing in a prepared hazard field at the Kennedy Space Center (KSC). This paper describes Morpheus integrated testing campaign, infrastructure, and facilities, and the payloads being incorporated on the vehicle. The Project s fast pace, rapid prototyping, frequent testing, and lessons learned depart from traditional engineering development at JSC. The Morpheus team employs lean, agile development with a guiding belief that technologies offer promise, but capabilities offer solutions, achievable without astronomical costs and timelines

Diel CO2 cycles reduce severity of bahavioural abnormalities in coral reef fish under ocean acidification

Elevated CO2 levels associated with ocean acidification (OA) have been shown to alter behavioural responses in coral reef fishes. However, all studies to date have used stable pCO2 treatments, not considering the substantial diel pCO2 variation that occurs in shallow reef habitats. Here, we reared juvenile damselfish, Acanthochromis polyacanthus, and clownfish, Amphiprion percula, at stable and diel cycling pCO2 treatments in two experiments. As expected, absolute lateralization of A. polyacanthus and response to predator cue of Am. percula were negatively affected in fish reared at stable, elevated pCO2 in both experiments. However, diel pCO2 fluctuations reduced the negative effects of OA on behaviour. Importantly, in experiment two, behavioural abnormalities that were present in fish reared at stable 750 μatm CO2 were largely absent in fish reared at 750 ± 300 μatm CO2. Overall, we show that diel pCO2 cycles can substantially reduce the severity of behavioural abnormalities caused by elevated CO2. Thus, past studies may have over-estimated the impacts of OA on the behavioural performance of coral reef fishes. Furthermore, our results suggest that diel pCO2 cycles will delay the onset of behavioural abnormalities in natural populations

Investigations into the Toxicology of Spirolides, a Group of Marine Phycotoxins

Spirolides are marine phycotoxins produced by the dinoflagellates Alexandrium ostenfeldii and A. peruvianum. Here we report that 13-desmethyl spirolide C shows little cytotoxicity when incubated with various cultured mammalian cell lines. When administered to mice by intraperitoneal (ip) injection, however, this substance was highly toxic, with an LD50 value of 6.9 µg/kg body weight (BW), showing that such in vitro cytotoxicity tests are not appropriate for predicting the in vivo toxicity of this toxin. Four other spirolides, A, B, C, and 20-methyl spirolide G, were also toxic to mice by ip injection, with LD50 values of 37, 99, 8.0 and 8.0 µg/kg BW respectively. However, the acute toxicities of these compounds were lower by at least an order of magnitude when administration by gavage and their toxic effects were further diminished when administered with food. These results have implications for future studies of the toxicology of these marine toxins and the risk assessment of human exposure

Trypanosoma brucei aquaglyceroporin 2 is a high-affinity transporter for pentamidine and melaminophenyl arsenic drugs and the main genetic determinant of resistance to these drugs.

OBJECTIVES: Trypanosoma brucei drug transporters include the TbAT1/P2 aminopurine transporter and the high-affinity pentamidine transporter (HAPT1), but the genetic identity of HAPT1 is unknown. We recently reported that loss of T. brucei aquaglyceroporin 2 (TbAQP2) caused melarsoprol/pentamidine cross-resistance (MPXR) in these parasites and the current study aims to delineate the mechanism by which this occurs. METHODS: The TbAQP2 loci of isogenic pairs of drug-susceptible and MPXR strains of T. brucei subspecies were sequenced. Drug susceptibility profiles of trypanosome strains were correlated with expression of mutated TbAQP2 alleles. Pentamidine transport was studied in T. brucei subspecies expressing TbAQP2 variants. RESULTS: All MPXR strains examined contained TbAQP2 deletions or rearrangements, regardless of whether the strains were originally adapted in vitro or in vivo to arsenicals or to pentamidine. The MPXR strains and AQP2 knockout strains had lost HAPT1 activity. Reintroduction of TbAQP2 in MPXR trypanosomes restored susceptibility to the drugs and reinstated HAPT1 activity, but did not change the activity of TbAT1/P2. Expression of TbAQP2 sensitized Leishmania mexicana promastigotes 40-fold to pentamidine and >1000-fold to melaminophenyl arsenicals and induced a high-affinity pentamidine transport activity indistinguishable from HAPT1 by Km and inhibitor profile. Grafting the TbAQP2 selectivity filter amino acid residues onto a chimeric allele of AQP2 and AQP3 partly restored susceptibility to pentamidine and an arsenical. CONCLUSIONS: TbAQP2 mediates high-affinity uptake of pentamidine and melaminophenyl arsenicals in trypanosomes and TbAQP2 encodes the previously reported HAPT1 activity. This finding establishes TbAQP2 as an important drug transporter

A Key Role for Old Yellow Enzyme in the Metabolism of Drugs by Trypanosoma cruzi

Trypanosoma cruzi is the etiological agent of Chagas' disease. So far, first choice anti-chagasic drugs in use have been shown to have undesirable side effects in addition to the emergence of parasite resistance and the lack of prospect for vaccine against T. cruzi infection. Thus, the isolation and characterization of molecules essential in parasite metabolism of the anti-chagasic drugs are fundamental for the development of new strategies for rational drug design and/or the improvement of the current chemotherapy. While searching for a prostaglandin (PG) F2α synthase homologue, we have identified a novel “old yellow enzyme” from T. cruzi (TcOYE), cloned its cDNA, and overexpressed the recombinant enzyme. Here, we show that TcOYE reduced 9,11-endoperoxide PGH2 to PGF2α as well as a variety of trypanocidal drugs. By electron spin resonance experiments, we found that TcOYE specifically catalyzed one-electron reduction of menadione and β-lapachone to semiquinone-free radicals with concomitant generation of superoxide radical anions, while catalyzing solely the two-electron reduction of nifurtimox and 4-nitroquinoline-N-oxide drugs without free radical production. Interestingly, immunoprecipitation experiments revealed that anti-TcOYE polyclonal antibody abolished major reductase activities of the lysates toward these drugs, identifying TcOYE as a key drug-metabolizing enzyme by which quinone drugs have their mechanism of action

Novel minor groove binders cure animal African trypanosomiasis in an in vivo mouse model

Animal African trypanosomiasis (AAT) is a significant socioeconomic burden for sub-Saharan Africa due to its huge impact on livestock health. Existing therapies including those based upon Minor Groove Binders (MGBs), such as the diamidines, which have been used for decades, have now lost efficacy in some places due to the emergence of resistant parasites. Consequently, the need for new chemotherapies is urgent. Here, we describe a structurally distinct class of MGBs, Strathclyde MGBs (S-MGBs), which display excellent in vitro activities against the principal causative organisms of AAT, Trypanosoma congolense and T. vivax. We also show the cure of T. congolense-infected mice by a number of these compounds. In particular, we identify S-MGB-234, compound 7, as curative using 2 applications of 50 mg/kg intraperitoneally. Crucially, we demonstrate that S-MGBs do not show cross-resistance with the current diamidine drugs and are not internalised via the transporters used by diamidines. This study demonstrates that S-MGBs have significant potential as novel therapeutic agents for animal African trypanosomiasis