736 research outputs found

    Unlearn

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    Timothy P. Schultz, PhD, Associate Dean of Academics at the Naval War College, delivered a version of the following as an address at NWC’s 13 November 2019 graduation ceremony

    Generalized reciprocal identities

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    Included in Ramanujan’s Notebooks are two reciprocal identities. The first identity connects the Rogers-Ramanujan continued fraction with an eta quotient. The second identity is a level thirteen analogue. These are special cases of a more general class of relations between eta quotients and modular functions defined by product generalizations of the Rogers-Ramanujan continued fraction. Each identity is shown to be a relation between generators for a certain congruence subgroup. The degree, form, and symmetry of the identities is determined from behavior at cusps of the congruence subgroup whose field of functions the parameters generate. The reciprocal identities encode information about fundamental units and class numbers for real quadratic fields

    Ramanujan–Sato series for 1/π

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    We compute Ramanujan–Sato series systematically in terms of Thompson series and their modular equations. A complete list of rational and quadratic series corresponding to singular values of the parameters is derived

    Who Are The Planetarians? A Demographic Survey Of Planetarium - Based Astronomy Educators

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    Over the last 100 years since the planetarium was invented and began to spread across the planet, discipline-based planetarium education researchers have worked diligently to catalog what concepts are taught in the planetarium and what audiences learn when attending a planetarium show. What is not clearly known is precisely ‘who’ it is that are teaching astronomy in planetaria. Numerous small-scale studies give hints about who plantarians are, but the existing participant demographics provided shed precious little insight about them as broad field of professional experts. Knowing “who planetarians are” is critical to education researchers who need to know when they are studying planetarium educators who are more or less typical of most people in the field and when, instead, they are studying people who are unusual outliers and far less representative of the broader population. As a first step toward obtaining a glimpse of who planetarium educators are, a brief survey was broadly distributed through contemporary social media networks frequented by planetarium educators posing the question, “who are you?” The results from 61 respondents showed that 90% had undergraduate degrees, half of which were in physics or astronomy, and 38% hold graduate degrees. Additionally, only 8% have amateur astronomy or hobbyist backgrounds or any substantive K-12 classroom teaching experience. Perhaps unique to planetarium-based astronomy educators, 38% report having extensive backgrounds in theater and performance, These findings suggest that planetarium educators are a fundamentally different sort of individual than those who teach K-12 astronomy or do outreach as an amateur astronomer and, as such, perhaps have very different professional development requirements and expectations from those other astronomy-education related professional development consumers

    Level 17 Ramanujan-sato Series

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    Two level 17 modular functions r=q2∏n=1∞(1−qn)(n17),s=q2∏n=1∞(1−q17n)3(1−qn)3 are used to construct a new class of Ramanujan–Sato series for 1/π. The expansions are induced by modular identities similar to those level of 5 and 13 appearing in Ramanujan’s Notebooks. A complete list of rational and quadratic series corresponding to singular values of the parameters is derived

    Oxygen transfer during aerobic exercise in a varanid lizard Varanus mertensi is limited by the circulation

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    Oxygen transfer during sustained maximal exercise while locomoting on a treadmill at 0.33 m s(-1) was examined in a varanid lizard Varanus mertensi at 35degreesC. The rate of oxygen consumption ((V)over dot (O 2)) increased with locomotion from 3.49+/-0.75 (mean+/-S.D.) to 14.0+/-4.0 ml O-2 kg(-1) min(-1). Ventilation (V-E) increased, aided by increases in both tidal volume and frequency, in direct proportion to (V)over dot(O 2). The air convection requirement ((V)over dot(E)/(V)over dot(O 2)=27) was therefore maintained, together with arterial Pa-CO 2 and Pa-O 2. The alveolar-arterial P-O 2 difference (PA(O 2)-Pa-O 2) also remained unchanged during exercise from its value at rest, which was approximately 20 mmHg. Pulmonary diffusion for carbon monoxide (0.116+/-0.027 ml kg(-1) min(-1) mmHg(-1)) was double the value previously reported in V. exanthematicus and remained unchanged with exercise. Furthermore, exercise was associated with an increase in the arterial-venous O-2 content difference (Ca-O2-Cv(O 2)), which was assisted by a marked Bohr shift in the hemoglobin saturation curve and further unloading of venous O-2. During exercise the increase in cardiac output ((Q)over dot(tot)) did not match the increase in (V)over dot(O2) such that the blood convection requirement ((Q)over dot(tot)/(V)over dot (O 2)) decreased from the pre-exercise value of approximately 35 to 16 during exercise. Together, the results suggest that ventilation and O-2 transfer across the lung are adequate to meet the aerobic needs of V. mertensi during exercise, but the decrease in the blood convection requirement in the presence of a large arterial-venous O-2 content difference suggests that a limit in the transport of O-2 is imposed by the circulation

    Effects of seasonal variation in prey abundance on field metabolism, water flux, and activity of a tropical ambush foraging snake

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    The responses of animals to seasonal food shortages can have important consequences for population dynamics and the structure and function of food webs. We investigated how an ambush foraging snake, the northern death adder Acanthophis praelongus, responds to seasonal fluctuations in prey availability in its tropical environment. In the dry season, field metabolic rates and water flux, as measured by doubly labeled water, were significantly lower than in the wet season. Unlike some other reptiles of the wet-dry tropics, death adders showed no seasonal difference in their resting metabolism. About 94% of the decrease in energy expended in the dry season was due to a decrease in activity and digestion, with lower body temperatures accounting for the remainder. In the dry season, death adders were less active and moved shorter distances between foraging sites than in the wet season. Analysis of energy expenditure suggested that adders fed no more than every 2-3 wk in the dry season but fed more frequently during the wet season. Unlike many lizards that cease feeding during the dry season, death adders remain active and attempt to maximize their energy intake year-round

    Nitrous oxide emissions from riparian forest buffers, warm-season and cool-season grass filters, and crop fields

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    Denitrification within riparian buffers may trade reduced nonpoint source pollution of surface waters for increased greenhouse gas emissions resulting from denitrification-produced nitrous oxide (N2O). However, little is known about the N2O emission within conservation buffers established for water quality improvement or of the importance of short-term N2O peak emission following rewetting dry soils and thawing frozen soils. Such estimates are important in reducing uncertainties in current Intergovernmental Panel on Climate Change (IPCC) methodologies estimating soil N2O emission which are based on N inputs. This study contrasts N2O emission from riparian buffer systems of three perennial vegetation types and an adjacent crop field, and compares measured N2O emission with estimates based on the IPCC methodology. We measured soil properties, N inputs, weather conditions and N2O fluxes from soils in forested riparian buffers, warm-season and cool-season grass filters, and a crop field located in the Bear Creek watershed in central Iowa, USA. Cumulative N2O emissions from soils in all riparian buffers (5.8 kg N2O-N ha−1 in 2006–2007) were significantly less than those from crop field soils (24.0 kg N2O-N ha−1 in 2006–2007), with no difference among the buffer vegetation types. While N2O peak emissions (up to 70-fold increase) following the rewetting of dry soils and thawing of frozen soils comprised 46–70% of the annual N2O emissions from soils in the crop field, soils in the riparian buffers were less sensitive to such events (3 to 10-fold increase). The ratio of N2O emission to N inputs within riparian buffers (0.02) was smaller than those of crop field (0.07). These results indicate that N2O emission from soils within the riparian buffers established for water quality improvement should not be considered a major source of N2O emission compared to crop field emission. The observed large difference between measured N2O emissions and those estimated using the IPCC\u27s recommended methodology (i.e., 87% underestimation) in the crop field suggests that the IPCC methodology may underestimate N2O emission in the regions where soil rewetting and thawing are common, and that conditions predicted by future climate-change scenarios may increase N2O emissions
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