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Early February (early + february)
Selected AbstractsThe growth respiration component in eddy CO2 flux from a Quercus ilex mediterranean forestGLOBAL CHANGE BIOLOGY, Issue 9 2004S. Rambal Abstract Ecosystem respiration, arising from soil decomposition as well as from plant maintenance and growth, has been shown to be the most important component of carbon exchange in most terrestrial ecosystems. The goal of this study was to estimate the growth component of whole-ecosystem respiration in a Mediterranean evergreen oak (Quercus ilex) forest over the course of 3 years. Ecosystem respiration (Reco) was determined from night-time carbon dioxide flux (Fc) using eddy correlation when friction velocity (u*) was greater than 0.35 m s,1 We postulated that growth respiration could be evaluated as a residual after removing modeled base Reco from whole-ecosystem Reco during periods when growth was most likely occurring. We observed that the model deviated from the night-time Fc -based Reco during the period from early February to early July with the largest discrepancies occurring at the end of May, coinciding with budburst when active aboveground growth and radial growth increment are greatest. The highest growth respiration rates were observed in 2001 with daily fluxes reaching up to 4 g C m,2. The cumulative growth respiration for the entire growth period gave total carbon losses of 170, 208, and 142 g C m,2 for 1999, 2001, and 2002, respectively. Biochemical analysis of soluble carbohydrates, starch, cellulose, hemicellulose, proteins, lignin, and lipids for leaves and stems allowed calculation of the total construction costs of the different growth components, which yielded values of 154, 200, and 150 g C for 3 years, respectively, corresponding well to estimated growth respiration. Estimates of both leaf and stem growth showed very large interannual variation, although average growth respiration coefficients and average yield of growth processes were fairly constant over the 3 years and close to literature values. The time course of the growth respiration may be explained by the growth pattern of leaves and stems and by cambial activity. This approach has potential applications for interpreting the effects of climate variation, disturbances, and management practices on growth and ecosystem respiration. [source] Printing the Regicide of Charles IHISTORY, Issue 296 2004MOS TUBB The execution of Charles I by the English republic on 30 January 1649 was the most unpopular political act of the seventeenth century. Yet within three weeks of Charles's death the leaders of the new government were ,cheerful and well pleased'. This article explores one of the key reasons for their good mood: they had just managed a polemical triumph. In the weeks following the regicide, parliament and its supporters had justified the king's execution with a wide array of printed documents. Further, various government agents severely hampered the republic's opponents from printing their own missives, thereby creating a fairly clear space for the pro-regicide press. Although the long-term impact may have been limited, there can be little doubt that the English republic and its proponents asserted a potent case for regicide in early February 1649. [source] Synchronized diapause termination of the peach twig borer Anarsia lineatella (Lepidoptera: Gelechiidae): Brownian motion with drift?PHYSIOLOGICAL ENTOMOLOGY, Issue 1 2010PETROS T. DAMOS The course of diapause development is studied for the first time for Anarsia lineatella (Zeller) (Lepidoptera: Gelechiidae) under field and laboratory conditions for three successive years (2005,2007) in northern Greece. Photoperiod has a significant influence on diapause termination and the mean number of days to pupation decreases progressively throughout the winter season. Cold storage, for at least 30 days at 4°C, results in a synchronized reactivation of the larvae, with the developmental time of larvae chilled for 45 and 60 days at 4°C becoming significantly shorter. A theoretical stochastic description of the effect of chilling on diapause termination is attempted. Larvae have discrete ,physiological stages' with different degrees of diapause intensity, and the insect passes through those stages with a probability distribution S(t) that evolves over time. This pattern of progressive transition is similar to Brownian motion and finally leads to a successfully synchronized diapause break in spring. Hence, A. lineatella overwinters in a weak diapause state and may complete diapause development in late January, although it shows synchronized termination in early February, after the experience of essential chilling. [source] Physiology of diapause and cold hardiness in overwintering pupae of the apple leaf miner Phyllonorycter ringoniella in JapanPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2002Yi-Ping Li Abstract The apple leaf miner Phyllonorycter ringoniella (Matsumura) (Lepidoptera: Gracillariidae) overwinters as a diapausing pupa. The diapause rate reaches 100% in early October. Diapause intensity decreases gradually from early October and diapause terminates in early February. The fresh body weight of diapausing pupae is 1.6 times that of non-diapausing pupae. The main cryoprotectant in P. ringoniella pupae is trehalose. Three stages are distinguishable as indicated by the correlations between diapause intensity, levels of cold hardiness and the trehalose content: diapause induction occurred in October, diapause development from November to December, and post-diapause quiescence from January to April. During diapause induction, the pupae accumulate low levels of trehalose and do not survive exposure to ,15 °C. During diapause development, the pupae gradually accumulate more trehalose and show some ability to survive exposure to ,15 °C, but not to ,20 °C. During post-diapause quiescence, the pupae accumulate relatively more trehalose and cold hardiness fully develops, but decreases quickly in April. The trehalose content in pupae sampled in December is unaffected by acclimation temperatures in the range 0,30 °C, but decreases in pupae sampled in March after acclimation at temperatures from 5 to 15 °C. These results suggest that overwintering pupae of P. ringoniella have the ability to accumulate trehalose and develop a high level of cold hardiness during diapause development. [source] Another Lesson about Public Opinion during the Clinton-Lewinsky ScandalPRESIDENTIAL STUDIES QUARTERLY, Issue 2 2002Stephen Earl Bennett Data from Pew Research Center polls from early February 1998 through late February 1999 show that only about a third of the American public followed media accounts of the Clinton-Lewinsky scandal "very closely," which is a facet of public reaction that has been largely neglected. Levels of heed paid to media stories about the scandal affected knowledge about key personalities and facets of the imbroglio. In addition, data show that the amount of attention paid to the news about the scandal resonated with opinions about diverse aspects of the scandal. Students of public opinion need to take the public's relative inattention to the scandal into account. [source] Effects of straw mulching on soil temperature, evaporation and yield of winter wheat: field experiments on the North China PlainANNALS OF APPLIED BIOLOGY, Issue 3 2007S.Y. Chen Abstract Straw mulching is an effective measure to conserve soil moisture. However, the existence of straw on the soil surface also affects soil temperature, which in turn influences crop growth, especially of winter crops. Five-year field experiments (2000,2005) investigated the effects of straw mulching and straw mass on soil temperature, soil evaporation, crop growth and development, yield and water use efficiency (WUE) of winter wheat (Triticum aestivum L.) at Luancheng Station on the North China Plain. Soil is a moderately well-drained loamy soil with a deep profile at the station. Two quantities of mulch were used: 3000 kg ha,1 [less mulching (LM)] and 6000 kg ha,1 [more mulching (MM)], representing half and all of the straw from the previous crop (maize). In the control (CK), the full quantity of mulch was ploughed into the top 20 cm of soil. The results showed that the existence of straw on the soil surface reduced the maximum, but increased the minimum diurnal soil temperature. When soil temperature was decreasing (from November to early February the next year), soil temperature (0,10 cm) under straw mulching was on average 0.3°C higher for LM and 0.58°C higher for MM than that without mulching (CK). During the period when soil temperature increased (from February to early April, the recovery and jointing stages of winter wheat), average daily soil temperature of 0,10 cm was 0.42°C lower for LM and 0.65°C lower for MM than that of CK. With the increase in leaf area index, the effect of mulching on soil temperature gradually disappeared. The lower soil temperature under mulch in spring delayed the development of winter wheat up to 7 days, which on average reduced the final grain yield by 5% for LM and 7% for MM compared with CK over the five seasons. Mulch reduced soil evaporation by 21% under LM and 40% under MM compared with CK, based on daily measuring of microlysimeters. However, because yield was reduced, the overall WUE was not improved by mulch. [source] Climate drivers of red wine quality in four contrasting Australian wine regionsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 2 2008C.J. SOAR Abstract Background and Aims: The understanding of the links between weather and wine quality is fragmented and often qualitative. This study quantified and integrated key weather variables during ripening, and their influence in red wine quality in the Hunter Valley, Margaret River, Coonawarra and Barossa Valley. Methods and Results: Long-term records of published vintage scores were used as an indicator of wine quality. A ,2 analysis was used to compare good (top 25%) versus poor (bottom 25%) vintages in relation to the frequency of defined weather conditions. Using maximum temperature as an example, better quality was associated with temperatures above 34°C throughout most of ripening in the Hunter, below 28°C in early January in the Margaret River, 28,33.9°C towards harvest in Coonawarra, and below 21.9°C in late January and early February and 28,30.9°C towards harvest in the Barossa. Conclusion: Our quantitative assessment allows for the timing and magnitude of weather influences on wine quality on a regional basis. Significance of the Study: The improved specificity of the links between weather and wine quality will help in the development of a risk analysis framework for wine quality across Australia. [source] | |||||||||||||