Estimating Tariff Equivalents of Nontariff Barriers

International Relations/Trade,

Action research on electrochemistry learning. Conceptual modelling intervention to promote disciplinary understanding, scientific inquiry, and reasoning

Students in engineering-science programmes often struggle with theoretical concepts, while they tend to adopt a surface approach to learning. We suggest that this can be tackled by promoting a specific higher-order thinking skill (HOTS) that enables drawing connections between physical phenomena and theoretical concepts representing them. We designed an intervention to support students in achieving deep insight into electrochemical phenomena, while developing this HOTS. Such intervention aims to scaffold students' learning and development by introducing conceptual modelling as an essential thinking skill of engineering-scientists, and as a strategy to build scientific understanding of natural phenomena. Therefore, conceptual modelling constitutes a main learning objective of this novel course. This paper reports an empirical investigation into how students deal with concepts and complexity, and to what extent the intervention has any measurable effects on the learning outcomes. This phenomenological investigation integrates considerations from various disciplines, and relies on multiple data sources, i.e., students' documents (lab journals and reports), observations of students in action (in discussions with their tutors and while performing lab experiments), and video stimulated-recall interviews. The results show little effect of the intervention, as implemented, suggesting how challenging it is for students (and instructors) to shift from traditional learning-and-teaching approaches, towards an epistemology of knowledge construction for specific problems. The findings are informative for revision of the intervention and generate specific recommendations. Concurrently, our operationalisation of the conceptual framework proves powerful in detecting qualitative differences in HOTS. Plausible implications for research and educational practice in science-engineering education are discussed.</p

Assessing molecular outflows and turbulence in the protostellar cluster Serpens South

Molecular outflows driven by protostellar cluster members likely impact their surroundings and contribute to turbulence, affecting subsequent star formation. The very young Serpens South cluster consists of a particularly high density and fraction of protostars, yielding a relevant case study for protostellar outflows and their impact on the cluster environment. We combined CO $J=1-0$ observations of this region using the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and the Institut de Radioastronomie Millim\'{e}trique (IRAM) 30 m single dish telescope. The combined map allows us to probe CO outflows within the central, most active region at size scales of 0.01 pc to 0.8 pc. We account for effects of line opacity and excitation temperature variations by incorporating $^{12}$CO and $^{13}$CO data for the $J=1-0$ and $J=3-2$ transitions (using Atacama Pathfinder Experiment and Caltech Submillimeter Observatory observations for the higher CO transitions), and we calculate mass, momentum, and energy of the molecular outflows in this region. The outflow mass loss rate, force, and luminosity, compared with diagnostics of turbulence and gravity, suggest that outflows drive a sufficient amount of energy to sustain turbulence, but not enough energy to substantially counter the gravitational potential energy and disrupt the clump. Further, we compare Serpens South with the slightly more evolved cluster NGC 1333, and we propose an empirical scenario for outflow-cluster interaction at different evolutionary stages.Comment: 26 pages, 15 figures, accepted for publication in the Astrophysical Journa

La estimulación neonatal por un ambiente nuevo mejora la producción de huevos en gallinas ponedoras

The development of behavioral and endocrine responses to acute stress is greatly influenced by the early postnatal rearing environment. These environmental effects persist throughout life, resulting in stable individual differences in fearfulness. Early stimulation, such as neonatal novelty exposure decreases behavioral reactivity. Previous reports also show that early–life stimulation, such as neonatal exposure to novelty, reduces behavioural reactivity. The aim of this study was to evaluate whether early stimulation increases egg production in adult laying eggs. One–day–old laying hen chicks were exposed to a T–maze (Method A) or a test based on the latency to peck (Method B), and then reared in an industrial poultry farm until adults. A group of non–stimulated hens was used as a control group. Weekly egg production, individual egg weight and weekly feed intake were measured in laying hens under farm conditions for 25 weeks. An increase in egg number was observed in stimulated laying hens by Method A (5.22 ± 0.06, p < 0.01) and by Method B (5.33 ± 0.08, p < 0.001) compared to the controls (4.78 ± 0.24). Likewise, the food conversion index was also greater for stimulated hens by Method A (0.356 ± 0.042; p < 0.05) and Method B (0.363 ± 0.053; p < 0.01), compared to the control group (0.330 ± 0.085). These results indicate that early stimulation could help to improve the adaptation of laying hens in industrial poultry farms. Key words: chick, early stimulation, egg production, laying hen, stress.El desarrollo de las respuestas comportamentales y endocrinas al estrés agudo está fuertemente influenciado por el entorno postnatal temprano. Estos efectos ambientales persisten a lo largo de la vida, generando diferencias individuales estables en la temerosidad. La estimulación temprana, como la exposición a un ambiente nuevo, disminuye la reactividad comportamental. También se demostró en investigaciones previas que una estimulación temprana en la vida, tal como una exposición neonatal al ambiente nuevo, redujo la reactividad comportamental. El objetivo de este estudio fue evaluar si una estimulación temprana aumenta la producción de huevos en gallinas adultas. Pollitos de gallinas ponedoras de un día de edad se expusieron a un laberinto en T (método A) o una prueba basada en la latencia para picotear un objeto (método B), posteriormente se trasladaron a una granja avícola hasta la edad adulta. Se designó a un grupo de gallinas como control, las cuales no se estimularon por ninguno de los métodos anteriormente nombrados. Durante 25 semanas se registró la postura semanal de huevos, el peso individual de los huevos y el consumo de alimento semanal en las gallinas ponedoras criadas bajo condiciones de granja. Se observó un aumento en el número de huevos en las gallinas estimuladas por el método A (5,22 ± 0,06, p < 0,01) y por el método B (5,33 ± 0,08, p < 0,001) comparadas a los controles no estimulados (4,78 ± 0,24). Del mismo modo, el índice de conversión alimenticia también fue mayor para las gallinas estimuladas por el método A (0,356 ± 0,042, p < 0,05) y el método B (0,363 ± 0,053, p < 0,01) respecto al grupo control (0,330 ± 0,085). Estos resultados indican que la estimulación temprana puede ayudar a mejorar la adaptación de gallinas ponedoras a las condiciones de cría intensiva en las granjas avícolas industriales. Palabras clave: pollito, estimulación temprana, producción de huevos, gallinas ponedoras, estrés

The UN in the lab

We consider two alternatives to inaction for governments combating terrorism, which we term Defense and Prevention. Defense consists of investing in resources that reduce the impact of an attack, and generates a negative externality to other governments, making their countries a more attractive objective for terrorists. In contrast, Prevention, which consists of investing in resources that reduce the ability of the terrorist organization to mount an attack, creates a positive externality by reducing the overall threat of terrorism for all. This interaction is captured using a simple 3×3 “Nested Prisoner’s Dilemma” game, with a single Nash equilibrium where both countries choose Defense. Due to the structure of this interaction, countries can benefit from coordination of policy choices, and international institutions (such as the UN) can be utilized to facilitate coordination by implementing agreements to share the burden of Prevention. We introduce an institution that implements a burden-sharing policy for Prevention, and investigate experimentally whether subjects coordinate on a cooperative strategy more frequently under different levels of cost sharing. In all treatments, burden sharing leaves the Prisoner’s Dilemma structure and Nash equilibrium of the game unchanged. We compare three levels of burden sharing to a baseline in a between-subjects design, and find that burden sharing generates a non-linear effect on the choice of the efficient Prevention strategy and overall performance. Only an institution supporting a high level of mandatory burden sharing generates a significant improvement in the use of the Prevention strategy

Jets and Outflows From Star to Cloud: Observations Confront Theory

In this review we focus on the role jets and outflows play in the star and planet formation process. Our essential question can be posed as follows: are jets/outflows merely an epiphenomenon associated with star formation or do they play an important role in mediating the physics of assembling stars both individually and globally? We address this question by reviewing the current state of observations and their key points of contact with theory. Our review of jet/outflow phenomena is organized into three length-scale domains: Source and Disk Scales ($0.1-10^2$ au) where the connection with protostellar and disk evolution theories is paramount; Envelope Scales ($10^2-10^5$ au) where the chemistry and propagation shed further light on the jet launching process, its variability and its impact on the infalling envelope; Parent Cloud Scales ($10^5-10^6$ au) where global momentum injection into cluster/cloud environments become relevant. Issues of feedback are of particular importance on the smallest scales where planet formation regions in a disk may be impacted by the presence of disk winds, irradiation by jet shocks or shielding by the winds. Feedback on envelope scales may determine the final stellar mass (core-to-star efficiency) and envelope dissipation. Feedback also plays an important role on the larger scales with outflows contributing to turbulent support within clusters including alteration of cluster star formation efficiencies (feedback on larger scales currently appears unlikely). A particularly novel dimension of our review is that we consider results on jet dynamics from the emerging field of High Energy Density Laboratory Astrophysics (HEDLA). HEDLA is now providing direct insights into the 3-D dynamics of fully magnetized, hypersonic, radiative outflows.Comment: Accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Hennin

Entomofauna associada à cultura da mandioca na região sul de Mato Grosso do Sul.

bitstream/item/38729/1/BP200637.pd

La relación isquiotibiales/cuadriceps como índice predictivo de gonartrosis

Se realiza un estudio muscular isocinético en grupo de 26 mujeres afectadas de gonartrosis, antes de la intervención, a los 6 meses y al año de la sustitución articular, realizando un estudio evolutivo y comparativo entre ambas rodillas con el objetivo de verificar si el balance muscular se altera paralelamente a la función articular y cual es su evolución tras la artroplastia. La rodilla artrósica presenta un cuádriceps más débil per conserva la función de la musculatura isquiotibial, con una relación isquiotibiales/cuádriceps aumentada patológicamente. Al año de la artroplastia no mejora la fuerza extensora, se conserva la fuerza flexora y se mantiene el balance muscular patológico. En la rodilla con menor afectación degenerativa la relación flexores/extensores se encuentra igualmente aumentada, por lo que se trata de su índice precoz de deterioro articular.An isokinetic muscular study was performed on a group of 26 women with primary gonarthrosis before surgery, six months and one year after joint replacement. An evaluative and comparative study of both knees was carried out in order to verify whether the muscular balance was altered in parallel with weaker but retained function of the ischiotibial musculature with an enhanced ischiotibial/quadriceps. One year after arthroplasty, extensor strength was not improved, though it was more efficient as revealed by reduced muscular fatigue, while flexor strength and pathological muscular balance were maintained. The flexor/extensor relation was also enhanced in the control knee, making this an early indicator of joint decoration

Successful reconstruction of whole mitochondrial genomes from ancient Central America and Mexico

The northern and southern peripheries of ancient Mesoamerica are poorly understood. There has been speculation over whether borderland cultures such as Greater Nicoya and Casas Grandes represent Mesoamerican outposts in the Isthmo-Colombian area and the Greater Southwest, respectively. Poor ancient DNA preservation in these regions challenged previous attempts to resolve these questions using conventional genetic techniques. We apply advanced in-solution mitogenome capture and high-throughput sequencing to fourteen dental samples obtained from the Greater Nicoya sites of Jícaro and La Cascabel in northwest Costa Rica (n = 9; A.D. 800–1250) and the Casas Grandes sites of Paquimé and Convento in northwest Mexico (n = 5; A.D. 1200–1450). Full mitogenome reconstruction was successful for three individuals from Jícaro and five individuals from Paquimé and Convento. The three Jícaro individuals belong to haplogroup B2d, a haplogroup found today only among Central American Chibchan-speakers. The five Paquimé and Convento individuals belong to haplogroups C1c1a, C1c5, B2f and B2a which, are found in contemporary populations in North America and Mesoamerica. We report the first successfully reconstructed ancient mitogenomes from Central America, and the first genetic evidence of ancestry affinity of the ancient inhabitants of Greater Nicoya and Casas Grandes with contemporary Isthmo-Columbian and Greater Southwest populations, respectively