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Selected AbstractsDebugging Decomposition Data,Comparative Taphonomic Studies and the Influence of Insects and Carcass Size on Decomposition RateJOURNAL OF FORENSIC SCIENCES, Issue 1 2010Tal Simmons Ph.D. Abstract:, Comparison of data from a variety of environments and ambient temperatures has previously been difficult as few studies used standardized measures of time/temperature and decomposition. In this paper, data from previous studies and recent experiments are compared using simple conversions. These conversions allow comparison across multiple environments and experiments for the first time. Plotting decomposition score against logADD allows the exponential progression of decomposition to be expressed as a simple linear equation. Data comparison from many environments and temperatures shows no difference in decomposition progression when measured using Accumulated Degree Days. The major effector of change in rate was insect presence, regardless of depositional environment, species, or season. Body size is significant when carcasses are accessed by insects; when insects are excluded, while bodies are indoors, submerged, or buried, then decomposition progresses at the same rate regardless of body size. [source] How 17-year cicadas keep track of timeECOLOGY LETTERS, Issue 4 2000R. Karban Seventeen-year periodical cicadas (Magicicada spp.) require 17 years to develop underground and all individuals at any location emerge synchronously within several days. The mechanisms that animals use to keep track of time are poorly understood and nothing is known about how cicada nymphs emerge after precisely 17 years. We altered the seasonal cycles of trees supporting cicada nymphs and thereby induced premature metamorphosis of the associated cicadas. This indicates that cicadas accomplish a consistently accurate 17-year preadult development time by counting host seasonal cycles and not either by the passage of real time or by the accumulation of degree days. [source] Effect of temperature on development, overwintering and establishment potential of Franklinothrips vespiformis in the UKENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2007Eleni Larentzaki Abstract This study investigated the effect of temperature on the development and overwintering potential of the predatory thrips Franklinothrips vespiformis (Crawford) (Thysanoptera: Aeolothripidae), a biological control agent used against glasshouse pests in continental Europe and Israel. Developmental rates increased linearly with rearing temperatures. It was estimated that 304.9 degree days, above a lower threshold temperature of 11.9 °C, were required for F. vespiformis to complete development from egg to adult eclosion. The effect of low temperatures (,5, 0, and 5 °C) was examined on adult female and larval survival. Subsequent reproductive and developmental attributes of survivors were also investigated. Lethal time experiments indicated that larval stages are more cold tolerant than adult F. vespiformis females. Surviving larvae increased their developmental times to adults with decreasing temperature and increasing exposure periods and second instars were significantly more successful than first instars in reaching adulthood. Surviving adult females decreased their oviposition rate with decreasing temperature and increasing exposure periods, and exposures to low temperatures affected the number of viable eggs produced. The results are discussed in the context of overwintering and establishment potential of F. vespiformis in the UK in the event of introducing the predatory thrips as a biological control agent against glasshouse pests. [source] Determination of essential oil quality index by using energy summation indices in an elite strain of Cymbopogon citratus (DC) Stapf [RRL(J)CCA12]FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2005Ashok Kumar Shahi Abstract Out of the several accessions of Cymbopogon citratus (DC) Stapf introduced from Central and West India, one accession coded as RRL(J)CCA12, selected through a mass selection technique, was found to have citral (,80%) as the major constituent in its essential oil. Citral has tremendous application in the ,avour and perfume industries. Plant adaptation was judged by quantifying the regression coef,cient (b) value, which was 1.0 using essential oil growth indices. For prediction of essential oil quality index (EOQI), a multiple regression equation was developed for the ,rst time by using essential oil yield/plant and energy summation indices as EOQI (citral %) = 61.6 + 1.09 × essential oil yield/plant (g) - 0.005 × heat use ef,ciency + 0.675 × phenothermal index. For obtaining a better quality of essential oil (citral ,78%), the optimal value of independent variable would be: X1 = 2.49; X2 = 0.018 and X3 = 20.47, where X1, X2 and X3 denote essential oil yield/plant, heat use ef,ciency and phenothermal index, respectively. The validation of the EOQI model is done by correlating the predicted and calculated values of citral (%) which exhibited signi,cant r value = 0.955 at 5% probability level. The thermal requirement of the selectant was ,5500 degree days to exhibit plant maturity in terms of qualitative and quantitative characteristics of its essential oil at 6.0 vegetative lea,ng stage, with attainment of plant height ,1.0 m from previous date of harvest (December 2001). Prediction of essential oil quality by using the mathematical model is helpful for integrating the growth processes and evaluating crop management strategies. Copyright © 2004 John Wiley & Sons, Ltd. [source] A model for predicting the emergence of dragonflies in a changing climateFRESHWATER BIOLOGY, Issue 9 2008OTTO RICHTER Summary 1. Precise models for the phenology of different species are essential for predicting the potential effects of any temporal mismatch of life cycles with environmental parameters under different climate change scenarios. Here we investigated the effects of ambient water temperature on the onset and synchrony of emergence for a widespread European riverine dragonfly, Gomphus vulgatissimus. 2. Long-term field data on the annual emergence from two rivers in northern Germany, and additional data from a laboratory experiment with different temperature regimes, were used to develop a model that predicted the onset of emergence by using mainly the temperature sum (degree days) as a parameter. 3. Model predictions of the onset of emergence fitted the observations well and could be transferred between localities. This was particularly so when weighting early winter temperature data by using a day length and a temperature-response function, implying potential additional control mechanisms for the onset of emergence. 4. We simulated effects of different winter temperature regimes on the emergence curves in order to predict the effects of climate change. These indicated an acceleration of emergence by 6,7 days per 1 °C temperature increase, which is corroborated by the laboratory data and is in the upper range of data published for other dragonflies. [source] A quantitative review comparing the yield of switchgrass in monocultures and mixtures in relation to climate and management factorsGCB BIOENERGY, Issue 1 2010DAN WANG Abstract Switchgrass (Panicum virgatum L.), a US Department of Energy model species, is widely considered for US biomass energy production. While previous studies have demonstrated the effect of climate and management factors on biomass yield and chemical characteristics of switchgrass monocultures, information is lacking on the yield of switchgrass grown in combination with other species for biomass energy. Therefore, the objective of this quantitative review is to compare the effect of climate and management factors on the yield of switchgrass monocultures, as well as on mixtures of switchgrass, and other species. We examined all peer-reviewed articles describing productivity of switchgrass and extracted dry matter yields, stand age, nitrogen fertilization (N), temperature (growing degree days), and precipitation/irrigation. Switchgrass yield was greater when grown in monocultures (10.9 t ha,1, n=324) than when grown in mixtures (4.4 t ha,1, n=85); yield in monocultures was also greater than the total yield of all species in the mixtures (6.9 t ha,1, n=90). The presence of legume species in mixtures increased switchgrass yield from 3.1 t ha,1 (n=65) to 8.9 t ha,1 (n=20). Total yield of switchgrass-dominated mixtures with legumes reached 9.9 t ha,1 (n=25), which was not significantly different from the monoculture yield. The results demonstrated the potential of switchgrass for use as a biomass energy crop in both monocultures and mixtures across a wide geographic range. Monocultures, but not mixtures, showed a significant positive response to N and precipitation. The response to N for monocultures was consistent for newly established (stand age <3 years) and mature stands (stand age ,3 years) and for lowland and upland ecotypes. In conclusion, these results suggest that fertilization with N will increase yield in monocultures, but not mixtures. For monocultures, N treatment need not be changed based on ecotype and stand age; and for mixtures, legumes should be included as an alternative N source. [source] Freezing of lakes on the Swiss plateau in the period 1901,2006INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 4 2008H. J. Hendricks Franssen Abstract Data of ice cover for deep Alpine lakes contain relevant climatological information since ice cover and winter temperature are closely related. For the first time, ice cover data from 11 lakes on the Swiss plateau have been collected and analysed for the period 1901,2006. The ice cover data used stem from systematic registration by individuals or groups (fishermen, an ice club and lake security service) and from several national, regional and local newspapers. It is found that in the past 40 years, and especially during the last two decades, ice cover on Swiss lakes was significantly reduced. This is in good agreement with the observed increase in the winter temperature in this period. The trend of reduced ice cover is more pronounced for lakes that freeze rarely than for the lakes that freeze more frequently. This agrees well with the stronger relative decrease in the probability to exceed the sum of negative degree days (NDD) needed for freezing the lakes that rarely freeze. The ice cover data are related with the temperature measurements such as the sum of NDD of nearby official meteorological stations by means of binomial logistic regression. The derived relationships estimate the probability of a complete ice cover on a lake as function of the sum of NDD. The sums of NDD needed are well related to the average depth of the lake (rNDD,Depth = 0.85). Diagnosing lake ice cover on the basis of the sum of NDD is much better than a prediction on the basis of a climatological freezing frequency. The variance of lake ice cover that cannot be explained by the sum of NDD is important for judging the uncertainty associated with climate reconstruction on the basis of data on lake ice cover. Copyright © 2007 Royal Meteorological Society [source] The generation of monthly gridded datasets for a range of climatic variables over the UKINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 8 2005Matthew Perry Abstract Monthly or annual 5 km × 5 km gridded datasets covering the UK are generated for the 1961,2000 period, for 36 climatic parameters. As well as the usual elements of temperature, rainfall, sunshine, cloud, wind speed, and pressure, derived temperature variables (such as growing-season length, heating degree days, and heat and cold wave durations) and further precipitation variables (such as rainfall intensity, maximum consecutive dry days, and days of snow, hail and thunder) are analysed. The analysis process uses geographical information system capabilities to combine multiple regression with inverse-distance-weighted interpolation. Geographic and topographic factors, such as easting and northing, terrain height and shape, and urban and coastal effects, are incorporated either through normalization with regard to the 1961,90 average climate, or as independent variables in the regression. Local variations are then incorporated through the spatial interpolation of regression residuals. For each of the climatic parameters, the choice of model is based on verification statistics produced by excluding a random set of stations from the analysis for a selection of months, and comparing the observed values with the estimated values at each point. This gives some insight into the significance, direction, and seasonality of factors affecting different climate elements. It also gives a measure of the accuracy of the method at predicting values between station locations. The datasets are being used for the verification of climate modelling scenarios and are available via the Internet. © Crown Copyright 2005. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. [source] A synoptic-scale climate analysis of anomalous snow water equivalent over the Northern Great Plains of the USAINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 8 2003Andrew Grundstein Abstract The Northern Great Plains is a region where variations in seasonal snow accumulation can have a dramatic affect on regional hydrology. In the past, one of the problems in studying snow hydrology has been obtaining information of sufficiently high temporal and spatial resolution on the water content of the snowpack. This project used a hybrid climatology of snow water equivalent (SWE) that incorporated both model and observed data. This climatology has a long time series (49 years) and a high spatial resolution (1° × 1°) sufficient for use in a climatic analysis. The long and complete time series of SWE generated in this project allowed for a comprehensive analysis of the meteorological and climate forcing mechanisms that influence the amount of SWE. The five largest (high SWE) and five smallest SWE (low SWE) accumulations on 1 March were examined. High SWE years received greater snowfall and fewer accumulated melting degree days throughout the season. Large SWE accumulations at the end of the season, however, were not always associated with deep snowpacks early in the season. Also, all five high SWE years had above normal snowfall in February. Years with small or no SWE had below-average snowfall but greater than average accumulated melting degree days. A synoptic analysis examined both atmospheric circulation and air mass frequencies to assess impacts on ablation and snowfall. A distinct difference in the frequency of different air mass during high SWE versus low SWE years was evident. High SWE years were characterized by substantially greater intrusions of the coldest and driest air mass type (dry polar). Low SWE years, in contrast, had a greater frequency of more moderate air masses (dry moderate and moist moderate). In years with above average SWE, negative departures in November,December,January,February composite 700 hPa field were evident across the continental USA and indicate a greater frequency of troughing across the study area. Low SWE years were characterized by a ridging pattern that reduced the likelihood of precipitation and may have aided in the intrusion of more moderate air masses. Copyright © 2003 Royal Meteorological Society [source] Experimental investigation of the performance of a solar-assisted ground-source heat pump system for greenhouse heatingINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 3 2005Onder Ozgener Abstract The main objective of the present study is to investigate the performance characteristics of a solar-assisted ground-source heat pump system (SAGSHPS) for greenhouse heating with a 50 m vertical 1¼ in nominal diameter U-bend ground heat exchanger. This system was designed and installed in the Solar Energy Institute, Ege University, Izmir (568 degree days cooling, base: 22°C, 1226 degree days heating, base: 18°C), Turkey. Based upon the measurements made in the heating mode, the heat extraction rate from the soil is found to be, on average, 54.08 Wm,1 of bore depth, while the required borehole length in meter per kW of heating capacity is obtained as 12.57. The entering water temperature to the unit ranges from 8.2 to 16.2°C, with an average value of 9.1°C. The greenhouse air is at a maximum day temperature of 25°C and night temperature of 14°C with a relative humidity of 40%. The heating coefficient of performance of the heat pump (COPHP) is about 2.13 at the end of a cloudy day, while it is about 2.84 at the end of sunny day and fluctuates between these values in other times. The COP values for the whole system are also obtained to be 5,15% lower than COPHP. Copyright © 2004 John Wiley & Sons, Ltd. [source] Glacial refugia for summer-green trees in Europe and south-west Asia as proposed by ECHAM3 time-slice atmospheric model simulationsJOURNAL OF BIOGEOGRAPHY, Issue 12 2007Suzanne A. G. Leroy Abstract Aim, To generate maps of potential refugia for summer-green trees during the Last Glacial Maximum (LGM). Locations, Southern Europe and south-western Asia. Methods, Time-slice simulations of the atmospheric climate with the ECHAM3 model are used for the LGM. Limiting factors beyond which cool and warm groups of deciduous trees cannot grow (such as temperature in growing degree days, minimum monthly temperature and precipitation in summer) are chosen. A limited validation by fossil pollen and charcoal records from LGM sites was done. Results, Two sets of maps extending from Europe to the Caspian region for cool and warm summer-green trees are presented. Three criteria are combined using contour lines to indicate confidence levels. Small areas within the three southern peninsulas of Europe (Spain, Italy and Greece) are highlighted as possible refugia for summer-green trees. Further, areas that have remained poorly known are now proposed as refugia, including the Sakarya,Kerempe region in northern Turkey, the east coast of the Black Sea and the area south of the Caspian Sea. Main conclusions, The maps produced in this study could be used to facilitate better long-term management for the protection of European and south-western Asian biodiversity. [source] Predicting the Postmortem Submersion Interval for Human Remains Recovered from U.K. Waterways,JOURNAL OF FORENSIC SCIENCES, Issue 2 2010Vivienne Heaton M.Sc. Abstract:, This article aims to increase accuracy in estimating the postmortem submersion interval (PMSI) for bodies recovered from rivers in the United Kingdom. Data were collected from closed case files, crime scene reports, and autopsy files concerning bodies recovered over a 15-year period from the River Clyde, Scotland, and the River Mersey and canals in northwest England. One hundred and eighty-seven cases met the study criteria and were scored by quantifying the overall amount of decomposition observed in each case. Statistical analysis showed that the duration of a body's submergence in water and the temperatures to which it was exposed, as measured in accumulated degree days (ADD), had a significant effect on the decay process. Further analysis indicated that there were no significant differences in decomposition between the waterways. By combining the data from all study samples, it was possible to produce a single linear regression model for predicting ADD from observed decomposition. [source] Inbreeding, outbreeding and environmental effects on genetic diversity in 46 walleye (Sander vitreus) populationsMOLECULAR ECOLOGY, Issue 2 2006CHRISTOPHER J. CENA Abstract Genetic diversity is recognized as an important population attribute for both conservation and evolutionary purposes; however, the functional relationships between the environment, genetic diversity, and fitness-related traits are poorly understood. We examined relationships between selected lake parameters and population genetic diversity measures in 46 walleye (Sander vitreus) populations across the province of Ontario, Canada, and then tested for relationships between six life history traits (in three categories: growth, reproductive investment, and mortality) that are closely related to fitness, and genetic diversity measures (heterozygosity, d2, and Wright's inbreeding coefficient). Positive relationships were observed between lake surface area, growing degree days, number of species, and hatchery supplementation versus genetic diversity. Walleye early growth rate was the only life history trait significantly correlated with population heterozygosity in both males and females. The relationship between FIS and male early growth rate was negative and significant (P < 0.01) and marginally nonsignificant for females (P = 0.06), consistent with inbreeding depression effects. Only one significant relationship was observed for d2: female early growth rate (P < 0.05). Stepwise regression models showed that surface area and heterozygosity had a significant effect on female early growth rate, while hatchery supplementation, surface area and heterozygosity had a significant effect on male early growth rate. The strong relationship between lake parameters, such as surface area, and hatchery supplementation, versus genetic diversity suggests inbreeding and outbreeding in some of the populations; however, the weak relationships between genetic diversity and life history traits indicate that inbreeding and outbreeding depression are not yet seriously impacting Ontario walleye populations. [source] Sampling designs of insect time series data: are they all irregularly spaced?OIKOS, Issue 1 2009D. V. Beresford Time series data are commonly obtained by trapping over a standardized period of time, for example daily or weekly. In this paper we present evidence that such sampling designs are inherently irregularly spaced due to the varying developmental rates and population parameters caused by changing temperatures during a sampling season. We modeled an exponentially growing population based on stable fly population growth rates, and then compare different sampling regimes to determine which produces the best estimate of population growth rate. These results are then compared to field data based on weekly sampling at three dairy farms in Ontario over two summers. Transforming catch numbers (N) to ln(N)/(number of degree days within the sampling period) corrects for the irregular spaced sampling in these data. These results support the use of measuring population parameters such as population growth rates in terms of degree days. [source] Temperature related effects on embryonic development of the Mediterranean locust, Dociostaurus maroccanusPHYSIOLOGICAL ENTOMOLOGY, Issue 2 2000E. Quesada-Moraga Summary Laboratory studies were conducted to assess the effect of temperature on the development of the eggs of Dociostaurus maroccanus (Thunberg) (Orthoptera, Acrididae) during anatrepsis (stages I,XIV) and during catatrepsis (stages XV,XX). The developmental rates of anatrepsis were studied at five constant temperatures ranging from 10 to 30°C. Egg development occurred over the entire range but at 10°C the embryos were unable to complete anatrepsis. The relationship between temperature and developmental times for completing anatrepsis was analysed by the non-linear Logan type III model. The optimal temperature estimated for the development of eggs during anatrepsis was 24.7°C; the lower and upper thermal thresholds were 9°C and 31°C, respectively. Once the embryos completed anatrepsis, only those incubated at 15°C continued morphogenesis beyond stage XIV (diapause stage) without a low-temperature exposure period. The developmental rate of catatrepsis was studied at four constant temperatures ranging from 15°C to 30°C after exposure to low-temperature, 10°C, for 30, 60 or 90 days. For catatrepsis, temperature and developmental time were linearly and inversely related. Linear regression was used to estimate the lower developmental threshold and the degree days requirements for catatrepsis. Both decreased with longer exposure to the low temperature; the former from 13.8°C to 10.5°C and the latter from 212.8 to 171.5 degree days, following 30 and 90 days at 10°C, respectively. Our results improve the ability of decision support systems for Mediterranean locust pest management by providing better forecasts to land managers and pest advisors. [source] Seasonal variations in production and development of leather leaf fern leaves,ANNALS OF APPLIED BIOLOGY, Issue 2 2003J O STRANDBERG Summary Production and development of leatherleaf fern leaves were studied using containerised plants growing in a shade house. Leaf development was partitioned into seven arbitrary development stages; the time needed for leaves to progress through each developmental stage was used to measure days required to reach maturity. Measurements were made twice each week throughout 1997. Means and variances with in emergence rates of new leaves and time needed for new leaves to pass through six leaf development stages were calculated for 26 14-day periods throughout the year and compared with degree days, solar radiation, soil temperature, and daylight hours accumulated during the periods. Leaf production rates ranged from 0.15,0.73 leaves day,1 plant,1. The average time from emergence to maturity was 22.6 days. Both leaf production and development rates varied greatly with the seasons, and were strongly associated with the weather variables measured, but significant cyclic rate fluctuations unrelated to weather were also detected. Leaf emergence rates were more strongly related to average soil temperature, whereas leaf development rates to maturity were more strongly related to solar radiation and degree days. [source] Factors affecting pollination ecology of Quercus anemophilous species in north-west SpainBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2005F. J. RODRÍGUEZ-RAJO Pollination ecology of Quercus is influenced by meteorological, biotic and genetic factors. This study was undertaken to ascertain the effect induced by these factors on pollen production, release and dispersion. Aerobiological data have been used in recent years as phenological information, because the presence of pollen in the air is the result of flowering across a wide area. The onset of the Quercus pollen season and the atmospheric pollen concentrations during the pollination period in two localities of north-west Spain (Ourense and Santiago) were determined from 1993 to 2001. There were important variations in total annual pollen as a result of meteorological conditions, lenticular galls produced by Neuropterus on catkins and biennial genetic rhythms of pollen production. In order to determine the beginning of flowering, a thermal time model has been used. Chill requirements were around 800 chilling hours (CH) and heat requirements were 953 growth degree days (GDD in °C) in Santiago and 586 GDD in Ourense. Pollen in the air show positive correlation (99% significance) with daily thermal oscillation, maximum and minimum temperatures, and hours of sunshine. Regression analysis with previous days' pollen concentrations explained the high percentage of pollen concentration variability, as meteorological variables do not, on their own, explain pollen production and release. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 149, 283,297. [source] | |||||||||||||||||||||||||