568 research outputs found

    Common climatic signal from glaciers in the European Alps over the last 50 years

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    Conventional glacier-wide mass balances are commonly used to study the effect of climate forcing on glacier melt. Unfortunately, the glacier-wide mass balances are also influenced by the glacier's dynamic response. Investigations on the effects of climate forcing on glaciers can be largely improved by analyzing point mass balances. Using a statistical model, we have found that 52% of the year-to-year deviations in the point mass balances of six glaciers distributed across the entire European Alps can be attributed to a common variability. Point mass balance changes reveal remarkable regional consistencies reaching 80% for glaciers less than 10 km apart. Compared to the steady state conditions of the 1962–1982 period, the surface mass balance changes are −0.85 m water equivalent (w.e.) a⁻¹ for 1983–2002 and −1.63 m w.e. a⁻¹ for 2003–2013. This indicates a clear and regionally consistent acceleration of mass loss over recent decades over the entire European Alps

    Re-examining the consumption-wealth relationship : the role of model uncertainty

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    This paper discusses the consumption-wealth relationship. Following the recent influential workof Lettau and Ludvigson [e.g. Lettau and Ludvigson (2001), (2004)], we use data on consumption, assets andlabor income and a vector error correction framework. Key …ndings of their work are that consumption doesrespond to permanent changes in wealth in the expected manner, but that most changes in wealth are transitoryand have no e¤ect on consumption. We investigate the robustness of these results to model uncertainty andargue for the use of Bayesian model averaging. We …nd that there is model uncertainty with regards to thenumber of cointegrating vectors, the form of deterministic components, lag length and whether the cointegratingresiduals a¤ect consumption and income directly. Whether this uncertainty has important empirical implicationsdepends on the researcher's attitude towards the economic theory used by Lettau and Ludvigson. If we workwith their model, our findings are very similar to theirs. However, if we work with a broader set of models andlet the data speak, we obtain somewhat di¤erent results. In the latter case, we …nd that the exact magnitudeof the role of permanent shocks is hard to estimate precisely. Thus, although some support exists for the viewthat their role is small, we cannot rule out the possibility that they have a substantive role to play

    Occurrence and distribution of Bemisia tabaci and Trialeurodes vaporariorum (Hemiptera: Aleyrodidae) on tomato crops in Panama

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    The main open-field and greenhouse producer regions of tomato in Panama (Los Santos, Herrera, Veraguas and Chiriquí provinces) were surveyed to determine the occurrence and distribution of Bemisia tabaci and Trialeurodes vaporariorum during the growing seasons of 2017 and 2018. Twenty-two plots were surveyed, and DNA extracts of 112 adult whiteflies were analyzed by multiplex PCR, using a set of specific primers of B. tabaci MEAM1, B. tabaci NW, and T. vaporariorum. DNA extracts corresponding to 57 individual whiteflies (50.9 %) rendered PCR products of expected size with B. tabaci-specific primers (37 belonged to B. tabaci MEAM1 and 20 to B. tabaci NW), whereas the remaining DNA extracts corresponding to 55 individual whiteflies (49.1 %) rendered the product of the expected size with T. vaporariorumspecific primers. The sequencing of those PCR products and BLAST analysis allowed for the identification of B. tabaci MEAM1, B. tabaci NW, and T. vaporariorum. Bemisia tabaci NW was detected in all four provinces, while B. tabaci MEAM1 was detected in the provinces of Los Santos, Herrera and Chiriquí, and T. vaporariorum was detected only in the province of Chiriquí. Bemisia tabaci MEAM1, B. tabaci NW and T. vaporariorum were detected in both production systems (open fields and greenhouse). Bemisia tabaci MEAM1 and B. tabaci NW were detected in the tropical rainforest (Af) and tropical savanna (Aw) climates, at an altitudinal range of 19–1543 meters above sea level (MASL), while Trialeurodes vaporariorum was found only in the Af climate, at an altitudinal range of 818–1661 MASL. To our knowledge, this is not only the first report of B. tabaci MEAM1 and B. tabaci NW at an altitude above 1000 MASL in Panama, but it is also the first report of T. vaporariorum at an altitude under 1000 MASL in this country. Information about the identification and geographic distribution of whiteflies in Panama will help to design effective strategies for pest management
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