387 research outputs found

    Adaptation Advantage to Climate Change Impacts on Road Infrastructure in Africa through 2100

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    The African continent is facing the potential of a US183.6billionliabilitytorepairandmaintainroadsdamagedfromtemperatureandprecipitationchangesrelatedtoclimatechangethrough2100.Asdetailed,thecentralpartofthecontinentfacesthegreatestimpactfromclimatechangewithcountriesfacinganaveragecostofUS183.6 billion liability to repair and maintain roads damaged from temperature and precipitation changes related to climate change through 2100. As detailed, the central part of the continent faces the greatest impact from climate change with countries facing an average cost of US22 million annually, if they adopt a proactive adaptation policy and a US$54 million annual average, if a reactive approach is adopted. Additionally, countries face an average loss of opportunity to expand road networks from a low of 22 per cent to a high of 235 per cent in the central region.infrastructure, climate change, roads, cost estimates

    Evaluation of force-torque displays for use with space station telerobotic activities

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    Recent experiments which addressed Space Station remote manipulation tasks found that tactile force feedback (reflecting forces and torques encountered at the end-effector through the manipulator hand controller) does not improve performance significantly. Subjective response from astronaut and non-astronaut test subjects indicated that force information, provided visually, could be useful. No research exists which specifically investigates methods of presenting force-torque information visually. This experiment was designed to evaluate seven different visual force-torque displays which were found in an informal telephone survey. The displays were prototyped in the HyperCard programming environment. In a within-subjects experiment, 14 subjects nullified forces and torques presented statically, using response buttons located at the bottom of the screen. Dependent measures included questionnaire data, errors, and response time. Subjective data generally demonstrate that subjects rated variations of pseudo-perspective displays consistently better than bar graph and digital displays. Subjects commented that the bar graph and digital displays could be used, but were not compatible with using hand controllers. Quantitative data show similar trends to the subjective data, except that the bar graph and digital displays both provided good performance, perhaps do to the mapping of response buttons to display elements. Results indicate that for this set of displays, the pseudo-perspective displays generally represent a more intuitive format for presenting force-torque information

    Changes in active site histidine hydrogen bonding trigger cryptochrome activation

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    Cryptochrome (CRY) is the principal light sensor of the insect circadian clock. Photoreduction of the Drosophila CRY (dCRY) flavin cofactor to the anionic semiquinone (ASQ) restructures a C-terminal tail helix (CTT) that otherwise inhibits interactions with targets that include the clock protein Timeless (TIM). All-atom molecular dynamics (MD) simulations indicate that flavin reduction destabilizes the CTT, which undergoes large-scale conformational changes (the CTT release) on short (25 ns) timescales. The CTT release correlates with the conformation and protonation state of conserved His378, which resides between the CTT and the flavin cofactor. Poisson-Boltzmann calculations indicate that flavin reduction substantially increases the His378 pKa. Consistent with coupling between ASQ formation and His378 protonation, dCRY displays reduced photoreduction rates with increasing pH; however, His378Asn/Arg variants show no such pH dependence. Replica-exchange MD simulations also support CTT release mediated by changes in His378 hydrogen bonding and verify other responsive regions of the protein previously identified by proteolytic sensitivity assays. His378 dCRY variants show varying abilities to light-activate TIM and undergo self-degradation in cellular assays. Surprisingly, His378Arg/Lys variants do not degrade in light despite maintaining reactivity toward TIM, thereby implicating different conformational responses in these two functions. Thus, the dCRY photosensory mechanism involves flavin photoreduction coupled to protonation of His378, whose perturbed hydrogen-bonding pattern alters the CTT and surrounding regions

    Analysis, characterization, and effects of heavy metal chealating agents in water

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    Students supported: 5 Student Assistants"The term 'chelating agents' refers to chemical ligands which bind to an element with more than one site. It is a ubiquitous term, since there are multitudes of compounds which fulfill the requirements for being called chelating agents. Their origin is both synthetic and natural, and the manner and fashion in which they bind is quite varied. Many of the vitamins and hormones essential to life are chelating agents. Chlorophyll, which is required for photosynthesis, consists of a porphyrin ring structure bound to magnesium. Hemoglobin binds iron in a similar pattern, and vitamin B-12 utilizes cobalt in the same fashion. In addition to these, there are quite a number of similar compounds in both plants and animals. Most metals transport and usage inside living things involve a chelation process. In natural water systems, the presence of chelating agents can have significant impact on the transport and toxicity of metals."--IntroductionProject # B-095-MO Agreement # 14-31-0001-409

    An ultrashort pulse ultra-violet radiation undulator source driven by a laser plasma wakefield accelerator

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    Narrow band undulator radiation tuneable over the wavelength range of 150–260 nm has been produced by short electron bunches from a 2 mm long laser plasma wakefield accelerator based on a 20 TW femtosecond laser system. The number of photons measured is up to 9 × 106 per shot for a 100 period undulator, with a mean peak brilliance of 1 × 1018 photons/s/mrad2/mm2/0.1% bandwidth. Simulations estimate that the driving electron bunch r.m.s. duration is as short as 3 fs when the electron beam has energy of 120–130 MeV with the radiation pulse duration in the range of 50–100 fs

    Development and Field Testing of a Narrative-Centered Digital Game for English Comprehension

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    This paper describes the development and field testing of Learning Likha: Rangers to the Rescue, a narrative-centered, mobile-based digital game for practicing English comprehension. Twenty-seven (27) student participants from Grades 4, 5, and 6 were invited to play the game and answer a comprehension test to determine their level of understanding of the game’s contents. Self-report questionnaires were also used to assess the extent to which they enjoyed playing the game. Three (3) teachers were likewise invited for a focus group discussion (FGD) to gather their insights about the game and how they may use it in their classes. Student’s self-reported feedback indicated they found the game fun, interesting, and sufficiently challenging. Post-test comprehension scores were generally good. Younger participants scored lower than their older peers but the differences were found to be not significant. Teachers indicated the game has the potential to be used as a supplement for their classes and that their students would enjoy playing it

    Development and Field Testing of a MALL for Filipino with a Reusable Framework for Mobile-Based Drills

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    This paper describes the development and field testing of Ibigkas! Filipino, a mobile game that exercises learners’ fluency in identifying synonyms (kasingkahulugan) and antonyms (kasalungat) in the Filipino language. Twenty-four students from Grades 4, 5, and 6 were invited to play and answer comprehension tests to determine whether the game helped them improve their understanding of the content. Self-report questionnaires assessed the extent to which they enjoyed it. Additionally, three teachers were invited to a focus group discussion (FGD) to gather their insights about the game and how they may use it in their classes. Self-report feedback from students showed the game was fun, interesting, and sufficiently challenging. A significant increase in the post-test comprehension scores of the Grade 4 participants was found. This shows the potential of the game to make learning fun while helping realize learning goals. Teachers indicated they can use the game to supplement their Filipino classes and that the students will be receptive to the idea of utilizing a game for learning

    The effects of administering different metaphylactic antimicrobials on growth performance and health outcomes of high-risk, newly received feedlot steers

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    Bovine respiratory disease (BRD) is the primary animal health concern facing feedlot producers. Many antimicrobial mitigation strategies are available, but few studies have compared feedlot performance during both the receiving and finishing periods following application of different antimicrobials used as metaphylaxis at arrival. The objective of this study was to compare antimicrobial metaphylaxis methods on clinical health and growth performance across both the receiving and finishing periods. A total of 238 multiple-sourced steers in two source blocks were used in a generalized complete block design. The four treatments included: 1) a negative control, 5 mL of sterile saline injected subcutaneously (CON); 2) subcutaneous administration of florfenicol at 40 mg/kg of BW (NUF); 3) subcutaneous administration of ceftiofur in the posterior aspect of the ear at 6.6 mg/kg of BW (EXC); and 4) subcutaneous administration of tulathromycin at 2.5 mg/kg of BW (DRA). The morbidity rate for the first treatment of BRD was decreased for the DRA and EXC treatments compared to CON and NUF (P \u3c 0.01). Additionally, average daily gain (ADG), dry matter intake (DMI), and gain-to-feed (G:F) were greater (P ≀ 0.02) in the DRA treatment during the receiving period compared to all other treatments. The ADG was also greater (P \u3c 0.05) for EXC than the CON treatment throughout the finishing period. Nonetheless, other growth performance variables did not differ among metaphylactic treatments during the finishing period (P ≄ 0.14). Likewise, no differences in carcass characteristics or liver abscess score were observed (P ≄ 0.18). All complete blood count (CBC) variables were affected by day (P ≀ 0.01) except mean corpuscular hemoglobin concentration (P = 0.29). Treatment × time interactions were observed for platelet count, white blood cell (WBC) count, monocyte count and percentage, and lymphocyte percentage (P ≀ 0.03). However, there were no observed hematological variables that differed among treatment (P ≄ 0.10). The results indicate that some commercially available antimicrobials labeled for metaphylactic use are more efficacious than others in decreasing morbidity rate
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