A preliminary determination of normal accelerations on racing airplanes

Rules and methods for insuring safe structural strength of racing airplanes used in the major air meets in this country have recently been considered. Acceleration records made in racing airplanes during actual air races were therefore considered desirable, and the NACA undertook the measurement of acceleration of loads on airplanes during all conditions of flight. Accelerations were measured on four airplanes at the Miami All-American Races in January 1934 and January 1935. The airplanes were representative of the fastest limited and unlimited displacement racing airplanes in current use in this country. Records during two races, or flights, on the race course were obtained with each airplane. The maximum normal acceleration recorded was 6.2g and the minimum was -1.2g

Further measurements of normal accelerations on racing airplanes

The work of collecting acceleration data for racing airplanes during races, started in January 1934, has been continued by obtaining similar data in the airplanes winning first and second places in the 1935 Thompson Trophy Race. Records were taken in the Howard Racer "Mr. Mulligan" and in the Wittman D-12 Racer. The maximum positive accelerations were generally smaller than those recorded in other airplanes during earlier races; the maximum in the Howard Racer was 2.8 g, and one value of 4.25 g was obtained in the Wittman Racer. Minimum values were as low as -0.55 g in the Howard Racer and 0.3 g in the Wittman Racer

Controlling the uncontrolled: Are there incidental experimenter effects on physiologic responding?

The degree to which experimenters shape participant behavior has long been of interest in experimental social science research. Here, we extend this question to the domain of peripheral psychophysiology, where experimenters often have direct, physical contact with participants, yet researchers do not consistently test for their influence. We describe analytic tools for examining experimenter effects in peripheral physiology. Using these tools, we investigate nine data sets totaling 1,341 participants and 160 experimenters across different roles (e.g., lead research assistants, evaluators, confederates) to demonstrate how researchers can test for experimenter effects in participant autonomic nervous system activity during baseline recordings and reactivity to study tasks. Our results showed (a) little to no significant variance in participants' physiological reactivity due to their experimenters, and (b) little to no evidence that three characteristics of experimenters that are well known to shape interpersonal interactions-status (using five studies with 682 total participants), gender (using two studies with 359 total participants), and race (in two studies with 554 total participants)-influenced participants' physiology. We highlight several reasons that experimenter effects in physiological data are still cause for concern, including the fact that experimenters in these studies were already restricted on a number of characteristics (e.g., age, education). We present recommendations for examining and reducing experimenter effects in physiological data and discuss implications for replication

Hair cortisol concentrations in relation to ill-being and well-being in healthy young and old females

Hair cortisol concentration (HCC) provides a retrospective measure of long-term (i.e. over a period of months) cortisol secretion and has been shown to be elevated in relation to chronic stress conditions. However associations in healthy participants with subjective ill-being are less clear and associations with well-being have not been explored. The current study examined HCC in relation to independent comprehensive measures of illbeing (stress, depression, anxiety) and well-being (subjective happiness, life satisfaction, psychological wellbeing) in healthy young and old females (mean ± SD: 19.5 ± 2.2 years and 78.6 ± 6.7 years respectively, total N = 115). The data supported evidence of increased total cortisol secretion with increased age. No association between ill-being and HCC was found in either the young or older group of participants. A positive association between HCC and well-being was found in the older participant group which was independent of ill-being and potential confounds. These findings do not support associations between HCC and ill-being in healthy young or old females. However the results suggest that HCC is able to distinguish levels of well-being in healthy older females

Genetic analyses of archival specimens of the Atlantic sturgeon Acipenser sturio L., 1758

Se analizó la variabilidad genética en Acipenser sturio L., 1758 y Acipenser oxyrinchus oxyrinchus Mitchill, 1815 usando la variación en la región D-loop del ADN mitocondrial y en un número de microsatélites (marcadores nucleares). El material estudiado incluyó muestras de tejidos de: (1) 38 ejemplares almacenados de A. sturio colectados en diferentes museos de historia natural alemanes, suecos, daneses y franceses; (2) 27 A. sturio vivos correspondientes al stock de cría para recuperación de esta especie en aguas alemanas (Instituto de Ecología Dulceacuícola y Pescas Interiores, Berlín, Alemania); (3) 30 A. o. oxyrinchus silvestres capturados en el océano Atlántico cerca de la costa de Nueva Jersey y en el río Delaware (USA); y (4) 60 individuos de A. o. oxyrinchus de un stock reproducido artificialmente obtenido originalmente de diversos esturiones silvestres capturados en el río San Juan (Canadá). Se clonó y secuenció un fragmento de 250 pares de bases de la región D-loop del ADN mitocondrial. La longitud de una unidad repetida fue de 80 pares de bases en A. sturio y de 79 en A. o. oxyrinchus. Las unidades repetidas de A. sturio y A. o. oxyrinchus difirieron por 11 sustituciones y una delección o inserción, respectivamente. No se encontró heteroplasmia. Se observaron tres diferentes haplotipos de ADN mitocondrial en ambas especies. Cinco microsatélites presentaron patrones polimórficos de bandas. En A. sturio los análisis de microsatélites mostraron una disminución en números alélicos entre los años 1823 y 1992. Este declive tuvo como consecuencia la fijación de varios alelos. Para A. sturio, se observaron un haplotipo de ADN mitocondrial y siete alelos sólo en los ejemplares almacenados. Los cálculos de distancia genética mostraron una gran similitud genética entre las poblaciones del Gironda y del Mar del Norte, y una posición basal de las poblaciones de A. sturio del Mediterráneo y del Adriático. En A. o. oxyrinchus el número de alelos de microsatélite varió entre 14 (ríos Hudson y San Juan) y 22 (río Delaware). Los cálculos de distancia genética mostraron una gran similitud genética entre las subpoblaciones de A. o. oxyrinchus.Genetic variability was analysed in Acipenser sturio L., 1758 and Acipenser oxyrinchus oxyrinchus Mitchill, 1815 using variation in the D-loop region of mtDNA and a number of microsatellites (nuclear markers). The studied material included tissue samples from: (1) 38 A. sturio archival specimens collected in different German, Swedish, Danish, and French museums of natural history; (2) 27 live A. sturio representing a broodstock for restoration of this species in German waters (Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany); (3) 30 wild A. o. oxyrinchus caught in the Atlantic Ocean near the coast of New Jersey and in the Delaware River (USA); and (4) 60 individuals of A. o. oxyrinchus from an artificially reproduced stock originally obtained from several wild sturgeons captured in the St. John River (Canada). A 250-bp fragment of the D-loop region of mtDNA was cloned and sequenced. The length of a repeated unit was 80 bp in A. sturio and 79 bp in A. o. oxyrinchus. The repeated units of A. sturio and A. o. oxyrinchus differed by 11 substitutions and one deletion or insertion, respectively. No heteroplasmy was found. Three different haplotypes of mtDNA were observed in both species. Five microsatellites had polymorphic band patterns. In A. sturio, analyses of microsatellites showed a decrease in allelic numbers between the years 1823 and 1992. This decline resulted in a fixation of several alleles. For A. sturio, one mtDNA haplotype and seven alleles were observed only in archival samples. Genetic distance calculations showed a great genetic similarity between A. sturio populations in the Gironde River and the North Sea, and a basal position of the Mediterranean and Adriatic Sea A. sturio populations. In A. o. oxyrinchus, the number of microsatellite alleles ranged between 14 (Hudson and St. John rivers) and 22 (Delaware River). Genetic distance calculations showed a high genetic similarity between subpopulations of A. o. oxyrinchus.Instituto Español de Oceanografí

Implications of albedo changes following afforestation on the benefits of forests as carbon sinks

Increased carbon storage with afforestation leads to a decrease in atmospheric carbon dioxide concentration and thus decreases radiative forcing and cools the Earth. However, afforestation also changes the reflective properties of the surface vegetation from more reflective pasture to relatively less reflective forest cover. This increase in radiation absorption by the forest constitutes an increase in radiative forcing, with a warming effect. The net effect of decreased albedo and carbon storage on radiative forcing depends on the relative magnitude of these two opposing processes. <br></br> We used data from an intensively studied site in New Zealand's Central North Island that has long-term, ground-based measurements of albedo over the full short-wave spectrum from a developing <i>Pinus radiata</i> forest. Data from this site were supplemented with satellite-derived albedo estimates from New Zealand pastures. The albedo of a well-established forest was measured as 13 % and pasture albedo as 20 %. We used these data to calculate the direct radiative forcing effect of changing albedo as the forest grew. <br></br> We calculated the radiative forcing resulting from the removal of carbon from the atmosphere as a decrease in radiative forcing of −104 GJ tC<sup>−1</sup> yr<sup>−1</sup>. We also showed that the observed change in albedo constituted a direct radiative forcing of 2759 GJ ha<sup>−1</sup> yr<sup>−1</sup>. Thus, following afforestation, 26.5 tC ha<sup>−1</sup> needs to be stored in a growing forest to balance the increase in radiative forcing resulting from the observed albedo change. Measurements of tree biomass and albedo were used to estimate the net change in radiative forcing as the newly planted forest grew. Albedo and carbon-storage effects were of similar magnitude for the first four to five years after tree planting, but as the stand grew older, the carbon storage effect increasingly dominated. Averaged over the whole length of the rotation, the changes in albedo negated the benefits from increased carbon storage by 17–24 %

Global Precipitation Measurement (GPM): Unified Precipitation Estimation From Space

Global Precipitation Measurement (GPM) is an international satellite mission that uses measurements from an advanced radar/radiometer system on a Core Observatory as reference standards to unify and advance precipitation estimates through a constellation of research and operational microwave sensors. GPM is a science mission focusing on a key component of the Earth's water and energy cycle, delivering near real-time observations of precipitation for monitoring severe weather events, freshwater resources, and other societal applications. This work presents the GPM mission design, together with descriptions of sensor characteristics, inter-satellite calibration, retrieval methodologies, ground validation activities, and societal applications

Modeling Carbon and Water Fluxes of Managed Grasslands: Comparing Flux Variability and Net Carbon Budgets between Grazed and Mowed Systems

The CenW ecosystem model simulates carbon, water, and nitrogen cycles following ecophysiological processes and management practices on a daily basis. We tested and evaluated the model using five years eddy covariance measurements from two adjacent but differently managed grasslands in France. The data were used to independently parameterize CenW for the two grassland sites. Very good agreements, i.e., high model efficiencies and correlations, between observed and modeled fluxes were achieved. We showed that the CenW model captured day-to-day, seasonal, and interannual variability observed in measured CO2 and water fluxes. We also showed that following typical management practices (i.e., mowing and grazing), carbon gain was severely curtailed through a sharp and severe reduction in photosynthesizing biomass. We also identified large model/data discrepancies for carbon fluxes during grazing events caused by the noncapture by the eddy covariance system of large respiratory losses of C from dairy cows when they were present in the paddocks. The missing component of grazing animal respiration in the net carbon budget of the grazed grassland can be quantitatively important and can turn sites from being C sinks to being neutral or C sources. It means that extra care is needed in the processing of eddy covariance data from grazed pastures to correctly calculate their annual CO2 balances and carbon budgets