Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Summer

  • austral summer
  • boreal summer
  • dry summer
  • early summer
  • first summer
  • late summer
  • one summer
  • second summer
  • warm summer
  • wet summer

  • Terms modified by Summer

  • summer air temperature
  • summer camp
  • summer cohort
  • summer condition
  • summer day
  • summer diapause
  • summer drought
  • summer experiment
  • summer generation
  • summer monsoon
  • summer monsoon rainfall
  • summer month
  • summer mortality
  • summer peak
  • summer period
  • summer population
  • summer precipitation
  • summer rainfall
  • summer rainy season
  • summer sample
  • summer school
  • summer season
  • summer temperature

  • Selected Abstracts

    Images from the Woods Hole Summer of 2009 Embryology Course

    Article first published online: 24 SEP 200
    Shown are images of Drosophila melanogaster (Fruit fly), Xenopus laevis (African clawed frog), Schmidtea mediterranea (Planaria), Hydroides (Serpulid worm), Schistocerca americana (American bird grasshopper), Euprymna scolopes (Hawaiian bobtail squid), Ciona intestinalis (Vase tunicate), Phalangium opilio (Daddy longlegs), Artemia franciscana (Brine shrimp), Mustelus canis (Dogfish), Danio rerio (Zebrafish), Gallus gallus domesticus (Chicken), Mnemiopsis leidyi (Warty comb jelly), Oscarella carmela (Desmosponge), Chaetopterus variopedatus (Parchment worm), and the Marbled crayfish that were generated and taken by members of the Woods Hole Embryology Course in the summer of 2009. Photo credits: Neel Aluru, Otger Campas, Carlos Carmona-Fontaine, Sheng-hong Chen, Katrien De Mulder, April Dinwiddie, Adele M. Doyle, Antje Fischer, Claudiu Giurumescu, Lauretta Grasso, Alysha Heimberg, Francie Hyndman, Erin Kaltenbrun, Dov Lerman-Sinkoff, Dede Lyons, Chema Martin-Durán, Lara Marxreiter, Jeremy Mosher, Malea Murphy, Lee Niswander, Vincent Pasque, Nipam H. Patel, Alberto Roselló, Prashant Sharma, Ashley Siegel, Ajay Thomas, Frank Tulenko, Alex Vasilyev, and Naveen Wijesena. For more information on the Embryology Course, please visit [source]

    Partitioning phylogenetic and adaptive components of the geographical body-size pattern of New World birds

    GLOBAL ECOLOGY, Issue 1 2008
    Lizabeth Ramirez
    ABSTRACT Aim To evaluate seasonal body-size patterns for New World birds in geographical space, to develop environmental models to explain the gradients, and to estimate phylogenetic and adaptive contributions. Location The Western Hemisphere. Methods We used range maps to generate gridded geometric mean body masses. Summer and winter patterns were distinguished based on breeding and non-breeding ranges. We first generated the geographical gradients, followed by phylogenetic eigenvector regression to generate body sizes predicted by the birds' positions in a phylogenetic tree, which were used to generate the expected phylogenetic gradient. Subtracting the expected pattern from the observed pattern isolated the adaptive component. Ordinary least squares multiple-regression models examined factors influencing the phylogenetic, adaptive and combined components of the seasonal body-size patterns, and non-spatial and spatial models were compared. Results Birds are larger in the temperate zones than in the tropics. The gradient is quantitatively stronger in winter than in summer. Regression models explained 66.6% of the variance in summer mass and 45.9% of the variance in winter mass. In summer, phylogenetic and adaptive responses of birds contribute equally to the gradient. In winter, the gradient in North America is much stronger than that expected by taxonomic turnover, and responses of species independent of their family membership drive the overall pattern. Main conclusions We confirm Bergmann's rule in New World birds and conclude that winter temperatures ultimately drive the pattern, exerting selection pressures on birds that overwhelm patterns expected by phylogenetic inertia at the family level. However, in summer, the movement of migratory species into the temperate zone weakens the gradient and generates a pattern more congruent with that expected from the taxonomic composition of the fauna. The analytical method we develop here represents a useful tool for partitioning the phylogenetic and non-phylogenetic components of spatially explicit macroecological data. [source]

    Seasonal variation in emergency referrals to a Surgical Assessment Unit

    S. T. Ward
    Summary Objectives:, To identify any seasonal variation in the pattern of referrals to the Surgical Assessment Unit (SAU). Methods:, Admission data to the SAU were collected prospectively during two audit periods of 13 weeks each (winter 2004/2005 and summer 2005). The data were analysed comparing numbers of admissions over the two audit periods and variations in the presenting complaint. Results:, There were a significantly greater number of referrals to the SAU in the summer compared with winter (999 vs. 849, p = 0.026). Whilst there were no significant differences in the sex distribution of patients presenting with general surgical symptoms, a significantly greater proportion of male patients presented with urological symptoms. Additionally, a significantly greater proportion of patients presented in the summer with scrotal/testicular symptoms compared with the winter (13.9% vs. 8.5%, p = 0.02). There was no significant difference between the two periods in terms of other diagnoses. In both study periods, the SAU was busy during weekdays compared with weekends. Whilst most patients arrived in the SAU between 9 am and midnight a smaller but not insignificant number arrived outside of these hours. Conclusions:, Summer compared with winter was a busy period for the SAU. This may be important in managing emergency surgical admissions. A significantly greater proportion of patients presented with scrotal/testicular symptoms during the summer, the reasons for which are unclear. The SAU diverts workload away from busy Accident & Emergency departments. [source]

    Is season important for the diagnosis of cutaneous melanoma in southern Brazil?

    A 10-year hospital-based study
    Background, Exposure to sunlight is an important etiologic factor in cutaneous melanoma (CM). In several countries, more cases of CM are diagnosed in summer than in winter. Aim, To analyze whether there is seasonal variation in the diagnosis of CM in southern Brazil. Methods, Data were collected from a hospital-based registry, including all cases of CM diagnosed between 1996 and 2005. Summer to winter and spring to fall ratios were used for the analysis, and a 95% confidence interval (CI) was calculated using Poisson regression. Results, Two hundred and eighty-one patients were diagnosed in this period. Although some months were shown to have higher absolute numbers of diagnosed melanomas (April, July, and January), there was no statistically significant seasonal variation in most of the melanomas in terms of either the summer to winter ratio [odds ratio (OR) = 1.09; 95% CI, 0.77,1.44] or spring to autumn ratio (OR = 1.01; 95% CI, 0.71,1.43). Only the number of lentigo maligna melanomas (LMMs) diagnosed in summer was higher than that in winter (OR = 2.83; 95% CI, 1.07,8.78). Conclusions, In southern Brazil, CMs do not seem to be more frequently diagnosed in summer than in winter. Darkening of melanocytic lesions and increased awareness of skin lesions during the summer could be possible explanations for LMMs being more frequently diagnosed in summer than in winter in this sample. [source]

    Summer and winter diet of the Cape white-eye Zosterops pallidus in South African grassland

    Grzegorz Kopij
    No abstract is available for this article. [source]

    Optimum Postmortem Chilled Storage Temperature for Summer and Winter Acclimated, Rested, Chinook Salmon (Oncorhynchus tshawytscha) White Muscle

    A.R. Jerrett
    ABSTRACT Chemical anaesthesia (AQUI-STM) was used to harvest 2 groups of tank-reared chinook salmon (Oncorhynchus tshawytscha), naturally acclimated to summer (18.8 °C) and winter (10.7 and 12.4 °C) temperatures, in a "rested"state. Carcasses were stored in 35% seawater at temperatures between approximately 2 and 19 °C to investigate the effects of acclimation and storage temperature on the postmortem metabolic rate of rested epaxial white muscle tissue. Muscle pH, [lactate], and adenosine triphosphate/inosine monophosphate measurements made 20 h postharvest indicated that winter acclimated fish were 2.2 times more sensitive to temperature than summer fish. A 3rd group of winter acclimated fish, stored between ,1.2 and 6 °C, indicated that significant cold injury only occurred on freezing. [source]

    This Ain't the Summer of Love: Conflict and Crossover in Heavy Metal and Punk,by Steve Waksman

    Theo Cateforis
    First page of article [source]


    Mary H. Nichols
    ABSTRACT: The climate of Southern Arizona is dominated by summer precipitation, which accounts for over 60 percent of the annual total. Summer and non-summer precipitation data from the USDA-ARS Walnut Gulch Experimental Watershed are analyzed to identify trends in precipitation characteristics from 1956 to 1996. During this period, annual precipitation increased. The annual precipitation increase can be attributed to an increase in precipitation during non-summer months, and is paralleled by an increase in the proportion of annual precipitation contributed during non-summer months. This finding is consistent with previously reported increases in non-summer precipitation in the southwestern United States. Detailed event data were analyzed to provide insight into the characteristics of precipitation events during this time period. Precipitation event data were characterized based on the number of events, event precipitation amount, 30-minute event intensity, and event duration. The trend in non-summer precipitation appears to be a result of increased event frequency since the number of events increased during nonsummer months, although the average amount per event, average event intensity, and average event duration did not. During the summer "monsoon" season, the frequency of recorded precipitation events increased but the average precipitation amount per event decreased. Knowledge of precipitation trends and the characteristics of events that make up a precipitation time series is a critical first step in understanding and managing water resources in semiarid ecosystems. [source]

    Threshold wind velocity as an index of soil susceptibility to wind erosion under variable climatic conditions

    Laura A. de Oro
    Abstract Wind erosion starts when the threshold wind velocity (µt) is exceeded. We evaluated the sensitivity of µt to determine the wind erosion susceptibility of soils under variable climatic conditions. Three years field data were used to calculate µt by means of the equation µt,=,, - , ,,1 (,), where , is the mean wind speed (m,s,1), , the , standard deviation (m,s,1), , the saltation activity and , the standard normal distribution function of ,. Saltation activity was measured with a piezoelectric sensor (Sensit). Results showed that , of the whole studied period (3·41 m,s,1) was lower than µt (7·53,m,s,1), therefore, wind erosion was produced mainly by wind gusts. The µt values ordered in the sequence: Winter (6·10 m,s,1),<,Spring (8·22,m,s,1),=,Summer (8·28,m,s,1),<,Autumn (26·48,m,s,1). Higher µt values were related to higher air humidity and lower wind speeds and temperatures. The µt values did not agree with the erosion amounts of each season, which ordered as follows: Summer (12·88,t ha,1),>,Spring (3·11,t ha,1),=,Winter (0·17,t ha,1),=,Autumn (no erosion). Low µt and erosion amounts of Winter were produced by a scarce number of gusts during eroding storms. We concluded that µt is useful as an index of soil susceptibility to wind erosion of different climatic periods. The use of a unique µt value in wind erosion prediction models can lead to erroneous wind erosion calculations. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Reflections on six years of the National Literacy Strategy in England: an interview with Stephen Anwyll, Director of the NLS 2001,2004

    LITERACY, Issue 3 2004
    Kathy Hall
    Abstract This recorded interview with Stephen Anwyll took place in Summer 2004, just prior to his departure from the post of Director of the National Literacy Strategy to take up a new post. In the interview, Stephen challenges those critics who characterise the Strategy as reductive and mechanistic, but recognises the potential for it to be interpreted in this way if not mediated through knowledgeable and confident teachers. He reflects on how the Strategy has changed and developed over time, and talks about new developments, including greater emphasis on the enjoyment of reading, the importance of encouraging speaking and listening and the recognition of the multiple literacies that children encounter and use. This interview is significant in that it places on public record, for the first time, the detailed views of policy makers at the centre of the NLS concerning the successes and challenges around the implementation and development of the Strategy during the last six years. It was recorded before the results of the 2004 standard assessment tests were known. The transcript below has not been edited into a formal written account. It retains the form of spoken discourse. [source]

    ISPAD Summer 2005 Newsletter

    PEDIATRIC DIABETES, Issue 3 2005
    Thomas Danne
    No abstract is available for this article. [source]

    Perceptions of mathematics curricula and teaching in China

    Robert Moy
    China and other East Asian countries (Japan, South Korea, Taiwan) have consistently outperformed the United States and other Western countries in mathematics achievement. As part of a Fulbright-sponsored trip to China in the Summer of 2002, a New York City public school teacher and a trainer of school psychologists offer their impressions of some of the reasons for these differences. Their impressions are based on observations of schools and classrooms, review of curricula, and a review of the literature. Four areas are covered: textbooks, curricula, teaching practices, and teacher knowledge. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 251,258, 2005. [source]

    Of conferences and conflicts: 16th Congress of the IUAES, China, Summer 2009

    ANTHROPOLOGY TODAY, Issue 6 2009
    Chris Hann
    The 16th Congress of the International Union of Anthropological and Ethnological Sciences in July 2009 was an opportunity for China to showcase socialist policies toward ethnic minorities. However just three weeks before the Congress 200 people were killed in ethnic rioting in Xinjiang. Hann's Narrative contrasts the dominant rhetoric of the Congress with the realities on the ground in rural eastern Xinjiang. [source]

    Digestive enzyme spectra in crustacean decapods (Paleomonidae, Portunidae and Penaeidae) feeding in the natural habitat

    Maria Santos Reis Bonorino Figueiredo
    Abstract This work describes the profile of five proteases and four carbohydrases from the crustacean decapods Macrobrachium australiense (Holthuis), Scylla serrata (Forskal), Portunus pelagicus (Linnaeus), Penaeus esculentus, Penaeus plebejus (Hess) and Metapenaeus bennettae (Racck & Dall), feeding in the natural habitat, in order to provide an indication of their digestive capabilities. The results raised the following points. First, species from each family showed a particular suite of digestive enzymes. Second, the activity of cellulase from M. australiensis and S. serrata, using AZCL-HE cellulose as the substrate, was around 90% higher than that observed with AZO-CM cellulose. However, for P. pelagicus and P. esculentus, the enzyme activity was better with AZO-CM cellulose. Third, M. australiense displayed the highest ratio of amylase to protease activity. In contrast, Portunidae species, P. pelagicus and S. serrata showed the lowest ratios. Fourth, comparison of the laminarinase activity of M. bennettae and P. esculentus in October (Spring) and December (early Summer) showed a significant decrease in December. Finally, the wide distribution of digestive enzymes in these crustaceans may reflect different feeding habits and habitats. [source]

    A geophysical investigation of subsurface structures and Quaternary geology at San Marcos Pueblo, New Mexico

    Emily A. Hinz
    Abstract San Marcos Pueblo site (LA 98), located in the Galisteo Basin south of Santa Fe, New Mexico, encompasses the remains of 43 identified room blocks, a Spanish mission and 20 middens. As part of ongoing field investigations at San Marcos, students and faculty from the Summer of Applied Geophysical Experience (SAGE) field programme are using multiple geophysical techniques to non-invasively investigate the site. Modelling of the underlying Quaternary stream terrace geology and the detection of subsurface Pueblo-era features were accomplished through the integrated interpretation of data from seismic refraction and reflection, electromagnetic, magnetic and ground-penetrating radar methods. Although to date only a targeted spatially small extent of the site has been explored using these methods, the SAGE field programme has been able detect a variety of anthropogenic structures and debris. The SAGE field programme validated the presence of excavations in the natural stream terrace sequence over areas believed to contain kivas, mapped the geometry of walls over a closed room block, and detected an area of magnetized debris associated with smelting operations. Collectively, the data from the SAGE field programme demonstrate the value of using multiple, complementary, geophysical methods for archaeological prospection. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Evaluating the Performance of Third-Party Logistics Arrangements: A Relationship Marketing Perspective

    A. Michael Knemeyer
    SUMMARY By 2005, users of third-party logistics services may be spending an average of nearly one-third of their total logistics budgets (compared to 20 percent today) to support 3PL services (Gooley 2000). Yet, very little research has examined managerial activities that might influence the performance of these logistics outsourcing relationships. Over the past several years, the management approach that views relationships as key assets of the organization has gained increased prominence in the priorities and practices of many companies (Gruen, Summers and Acito 2000). The current study utilizes this relationship marketing perspective as the basis for evaluating the perceived performance of third-party logistics arrangements. In particular, the current study examines the influence of six key relationship marketing dimensions on a customer's perceptions of their 3PL provider's performance. In so doing, the article builds on research (e.g., Goldsby and Stank 2000) that focuses on potential linkages between logistical performance metrics and managerial activities. The results suggest linkages between relationship marketing activities and the perceived performance of the 3PL arrangement. [source]

    Tryptophanase in sRNA control of the Escherichia coli cell cycle

    Dhruba K. Chattoraj
    Summary The field of gene regulation underwent a major revolution with the discovery of small non-coding RNAs (sRNAs) and the various roles they play in organisms from bacteria to man. Escherichia coli has more than 60 sRNAs that are transcribed primarily from intergenic regions. They usually target the leader region of mRNAs and prevent their translation. Protein targets are relatively rare. In this issue of Molecular Microbiology, Chant and Summers provide an example of a totally unexpected protein target. They show that dimers of plasmid ColE1 make an sRNA that interacts directly with the enzyme tryptophanase and enhances its affinity for its substrate, tryptophan. A breakdown product, indole, then arrests cell division until the dimers are resolved to monomers. The monomerization helps to prevent plasmid loss. Targeting a catabolic enzyme to buy time for recombination is an amazing example of adaptation, which illustrates the power of a selfish element (a plasmid in this case) to exploit the host cell machinery to its advantage. [source]

    The Trial on Trial: Volume Three: Towards a Normative Theory of the Criminal Trial by A. Duff, L. Farmer, S. Marshall and V. Tadros (Eds.) and Fair Trials: The European Criminal Procedural Tradition and the European Court of Human Rights by S.J. Summers

    No abstract is available for this article. [source]

    Employers' Benefits from Workers' Health Insurance

    Ellen O'Brien
    Most nonelderly americans receive their health insurance coverage through their workplace. Almost all large firms offer a health insurance plan, and even though they face greater barriers to providing coverage, so do the majority of very small firms. These employment-based plans cover two-thirds of nonelderly Americans and pay most of working families' expenses for health care and about one-quarter of national health spending. Despite employers' role in the health insurance market, however, very little attention has been paid to employers' motivations for providing health insurance to workers. Why do employers offer health insurance to workers? Is it because workers want it? Because their unions demand it? Or do employers offer health benefits to workers because their productivity and profitability depend on it? The standard economic theory of the availability of employer-provided health insurance focuses on worker demand (Cutler 1997; Pauly 1997; Summers 1989). Even though many employers believe that health insurance and health affect employees' productivity and firms' performance, health economists typically overlook and rarely measure firms' returns on health-related investments. Some research, however, suggests that firms may benefit economically by providing health insurance coverage for workers and their families. For example, health coverage may help employers recruit and retain high-quality workers. Health may contribute to productivity by reducing the costs of absenteeism and turnover and by increasing workers' productivity. This article reviews the evidence and proposes an agenda for future research. A better understanding of the benefits to employers of offering health coverage to workers may help clarify employers' behavior and help private employers and public officials make appropriate investments in health. [source]

    Maxillary sinus floor elevation using the (transalveolar) osteotome technique with or without grafting material.

    Part I: implant survival, patients' perception
    Abstract Objectives: To analyze the survival and success rates of implants installed utilizing the (transalveolar) osteotome technique, to compare peri-implant soft tissue parameters and marginal bone levels of osteotome-installed implants with implants placed using standard surgical procedures, and to evaluate patient-centered outcomes. Material and methods: During 2000 to 2005, 252 Straumann® dental implants were inserted in 181 patients. The surgical technique was a modification of the original osteotome technique presented by Summers. In addition to the clinical examination, the patients were asked to give their perception of the surgical procedure, utilizing a visual analogue scale. Results: The cumulative survival rate of the osteotome-installed implants after a mean follow-up time of 3.2 years, was 97.4% (95% confidence intervals: 94.4,98.8%). From the 252 implants inserted, three were lost before loading and another three were lost in the first and second year. According to residual bone height the survival was 91.3% for implant sites with ,4 mm residual bone height, and 90% for sites with 4 mm and 5 mm, when compared with that of 100% in sites with bone height of above 5 mm. According to implant length the survival rates were 100% for 12 mm, 98.7% for 10 mm, 98.7% for 8 mm and only 47.6% for 6 mm implants. Soft tissue parameters (pocket probing depth, probing attachment level, bleeding on probing and marginal bone levels) did not yield any differences between the osteotome-installed and the conventionally placed implants. More than 90% of the patients were satisfied with the implant therapy and would undergo similar therapy again if necessary. The cost associated with implant therapy was considered to be justified. Conclusion: In conclusion, the osteotome technique was a reliable method for implant insertion in the posterior maxilla, especially at sites with 5 mm or more of preoperative residual bone height and a relatively flat sinus floor. [source]

    Growth and movement patterns of early juvenile European anchovy (Engraulis encrasicolus L.) in the Bay of Biscay based on otolith microstructure and chemistry

    Abstract Various hypotheses have been put forward to explain the mechanisms in the Bay of Biscay that result in a good recruitment of European anchovy. Anchovy larvae from the spawning area in the Gironde River plume are advected towards off-shelf waters, where juveniles are commonly observed. Otolith microstructural and chemical analysis were combined to assess the importance of this off-shelf transport and to determine the relative contribution of these areas for anchovy survival. Chemical analysis of otoliths showed that anchovy juveniles in the Bay of Biscay can be divided into two groups: a group that drifts towards off-shelf waters early in their life and returns later, and a group that remains in the low salinity waters of the coastal area. The first group presents significantly faster growth rates (0.88 mm day,1) than those remaining in the coastal waters (0.32 mm day,1). This may be due to off-shelf waters being warmer in spring/summer, and to the fact that the lower food concentration is compensated for by higher prey visibility. Furthermore, the group of juveniles that drifted off the spawning area and had faster growth rates represents 99% of the juvenile population. These findings support the hypothesis that anchovy in the Bay of Biscay may use off-shelf waters as a spatio-temporal loophole, suggesting that transport off the shelf may be favourable for recruitment. [source]

    Impact of freshwater input and wind on landings of anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) in shelf waters surrounding the Ebre (Ebro) River delta (north-western Mediterranean)

    J. Lloret
    Abstract Time series analyses (Box,Jenkins models) were used to study the influence of river runoff and wind mixing index on the productivity of the two most abundant species of small pelagic fish exploited in waters surrounding the Ebre (Ebro) River continental shelf (north-western Mediterranean): anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus). River flow and wind were selected because they are known to enhance fertilization and local planktonic production, thus being crucial for the survival of fish larvae. Time series of the two environmental variables and landings of the two species were analysed to extract the trend and seasonality. All series displayed important seasonal and interannual fluctuations. In the long term, landings of anchovy declined while those of sardine increased. At the seasonal scale, landings of anchovy peaked during spring/summer while those of sardine peaked during spring and autumn. Seasonality in landings of anchovy was stronger than in sardine. Concerning the environmental series, monthly average Ebre runoff showed a progressive decline from 1960 until the late 1980s, and the wind mixing index was highest during 1994,96. Within the annual cycle, the minimum river flow occurs from July to October and the wind mixing peaks in winter (December,April, excluding January). The results of the analyses showed a significant correlation between monthly landings of anchovy and freshwater input of the Ebre River during the spawning season of this species (April,August), with a time lag of 12 months. In contrast, monthly landings of sardine were significantly positively correlated with the wind mixing index during the spawning season of this species (November,March), with a lag of 18 months. The results provide evidence of the influence of riverine inputs and wind mixing on the productivity of small pelagic fish in the north-western Mediterranean. The time lags obtained in the relationships stress the importance of river runoff and wind mixing for the early stages of anchovy and sardine, respectively, and their impact on recruitment. [source]

    European phenological response to climate change matches the warming pattern

    GLOBAL CHANGE BIOLOGY, Issue 10 2006
    Abstract Global climate change impacts can already be tracked in many physical and biological systems; in particular, terrestrial ecosystems provide a consistent picture of observed changes. One of the preferred indicators is phenology, the science of natural recurring events, as their recorded dates provide a high-temporal resolution of ongoing changes. Thus, numerous analyses have demonstrated an earlier onset of spring events for mid and higher latitudes and a lengthening of the growing season. However, published single-site or single-species studies are particularly open to suspicion of being biased towards predominantly reporting climate change-induced impacts. No comprehensive study or meta-analysis has so far examined the possible lack of evidence for changes or shifts at sites where no temperature change is observed. We used an enormous systematic phenological network data set of more than 125 000 observational series of 542 plant and 19 animal species in 21 European countries (1971,2000). Our results showed that 78% of all leafing, flowering and fruiting records advanced (30% significantly) and only 3% were significantly delayed, whereas the signal of leaf colouring/fall is ambiguous. We conclude that previously published results of phenological changes were not biased by reporting or publication predisposition: the average advance of spring/summer was 2.5 days decade,1 in Europe. Our analysis of 254 mean national time series undoubtedly demonstrates that species' phenology is responsive to temperature of the preceding months (mean advance of spring/summer by 2.5 days°C,1, delay of leaf colouring and fall by 1.0 day°C,1). The pattern of observed change in spring efficiently matches measured national warming across 19 European countries (correlation coefficient r=,0.69, P<0.001). [source]

    Testosterone-immunopositive primordial germ cells in the testis of the bullfrog, Rana catesbeiana

    JOURNAL OF ANATOMY, Issue 6 2005
    E. Sasso-Cerri
    Abstract In amphibia, steroidogenesis remains quiescent in distinct seasonal periods, but the mechanism by which spermatogenesis is maintained under low steroidogenic conditions is not clear. In the present study, testosterone location in the testes of Rana catesbeiana was investigated immunohistochemically during breeding (summer) and nonbreeding (winter) periods. In winter, the scarce interstitial tissue exhibited occasional testosterone immunopositivity in the interstitial cells but the cytoplasm of primordial germ cells (PG cells) was clearly immunopositive. By contrast, in summer, PG cells contained little or no immunoreactivity whereas strong immunolabelling was present in the well-developed interstitial tissue. These results suggest that PG cells could retain testosterone during winter. This androgen reservoir could be involved in the control of early spermatogenesis in winter and/or to guarantee spermiogenesis and spermiation in the next spring/summer. The weak or negative immunoreaction in the summer PG cells might reflect consumption of androgen reservoir by the intense spermatogenic activity from spring to summer. Thus, besides acting as stem cells, PG cells of R. catesbeiana could exert an androgen regulatory role during seasonal spermatogenesis. [source]

    Age, growth and reproduction of Marcusenius pongolensis, Oreochromis mossambicus and Schilbe intermedius in an oligotrophic impoundment in Swaziland

    Anthony J. Booth
    Abstract The age, growth and reproductive biology of Marcusenius pongolensis, Oreochromis mossambicus and Schilbe intermedius were investigated in the Mnjoli Dam, Swaziland. Otolith annulus formation occurred in winter for M. pongolensis, and in spring/summer for O. mossambicus and S. intermedius. Maximum ages of 8, 6 and 8 years were recorded for M. pongolensis, O. mossambicus and S. intermedius, respectively. Growth was described by the von Bertalanffy growth model as Lt = 238.73(1 , exp,0.27(t+2.27) mm fork length (FL) for M. pongolensis, Lt = 226.83(1 , exp,0.45(t+2.02)) mm total length (TL) for O. mossambicus, and Lt = 214.59(1 , exp,0.60(t+1.20)) mm FL for S. intermedius. Sexual maturity was estimated for male and female M. pongolensis at 134 mm FL and 119 mm FL, respectively. Marcusenius pongolensis matured within their first year. Female O. mossambicus and S. intermedius matured at 239 mm TL and 205 mm FL, corresponding to 2 and 4 years of age, respectively. Extended spawning periods, with two spawning peaks was observed for M. pongolensis, one in spring (September) and the second in autumn (March) and one peak over late-summer for S. intermedius. Résumé L'âge, la croissance et la biologie reproductive de Marcusenius pongolensis, Oreochromis mossambicus et Schilbe intermedius ont étéétudiés dans le barrage de Mnjoli, au Swaziland. La formation des anneaux des otolithes se passe en hiver pour M. pongolensis et au printemps/été pour O. mossambicus et S. intermedius. On a enregistré les âges maximum de 8, 6 et 8 ans respectivement pour Marcusenius pongolensis, Oreochromis mossambicus et Schilbe intermedius. La croissance a été décrite selon le modèle de croissance de von Bertalanffy selon la formule suivante: Lt = 238.73(1 , exp,0.27(t+2.27) mm LF pour M. pongolensis, Lt = 226.83(1 , exp,0.45(t+2.02)) mm LT pour O. mossambicus, et Lt = 214.59(1 , exp,0.60(t+1.20)) mm LF pour S. intermedius. On a estimé que la maturité sexuelle était atteinte à 134 LF et à 119 LF respectivement pour le mâle et la femelle de M. pongolensis, qui arrivaient à maturité au cours de leur première année. Les femelles d'O. mossambicus et de S. intermedius devenaient matures à 239 mm LT et 205 mm LF, ce qui correspond à l'âge de 2 et de 4 ans, respectivement. On a observé des périodes de frai prolongées, avec deux périodes de frai pour M. pongolensis, une au printemps (septembre) et la seconde en automne (mars), et un pic en fin d'été pour S. intermedius. [source]

    Glucose, fructose and sucrose content in broccoli, white cabbage and Portuguese cabbage grown in early and late seasons

    Eduardo Rosa
    Abstract Consumption of Portuguese cabbage and white cabbage is very high in Portugal, but diets including broccoli have been highly recommended owing to recognition of the health-protective effects of secondary plant metabolites. Broccoli production is generally concentrated in the summer/winter season, but the demand for a fresh product throughout the year requires production in other seasons. Sugars might affect flavour and the acceptance of broccoli by consumers. This study reports the free fructose, glucose and sucrose content in primary and secondary inflorescences of 11 cultivars of broccoli, one white cabbage and four Portuguese cabbages grown in early (March,July) and late (August,January) seasons in the northern region of Portugal. On average the results show that the total free sugar content in the broccoli cultivars, except for cv Marathon, is significantly (P,<,0.05) lower than in the other cabbages. Fructose was the major sugar in the three types of Brassica, representing between 48.8 and 56.9% of the total sugar content in broccoli cvs Marathon and Senshi respectively and between 48.7% (cv Mirandela) and 53.8% (cv Murciana) in the other cabbages. Glucose was the second major sugar, while sucrose represented a maximum of 20.5% in broccoli cv Shogun and 11.1% in cv Murciana. The growing season influenced the free sugar content, with generally higher levels in the spring/summer than in the summer/winter season in broccoli, while an opposite tendency was noted in the other Brassica species. In broccoli the sugar levels in the primary inflorescences were generally lower than in the secondary inflorescences, except for sucrose. © 2001 Society of Chemical Industry [source]

    Resistance to Leptosphaeria maculans (phoma stem canker) in Brassica napus (oilseed rape) induced by L. biglobosa and chemical defence activators in field and controlled environments

    PLANT PATHOLOGY, Issue 3 2006
    S. Y. Liu
    Effects of pretreatment of Brassica napus leaves with ascospores of Leptosphaeria biglobosa or chemical defence activators [acibenzolar- S -methyl (ASM) or menadione sodium bisulphite (MSB)] on infection by ascospores of Leptosphaeria maculans (phoma stem canker) and development of disease were studied in controlled-environment (phoma leaf spot) and field (phoma leaf spot and stem canker) experiments. In controlled-environment experiments, pretreatment of oilseed rape leaves (cv. Madrigal) with L. biglobosa, ASM or MSB delayed the appearance of L. maculans phoma leaf spot lesions. These pretreatments also decreased the phoma leaf spot lesion area in both pretreated leaves (local effect) and untreated leaves (systemic effect). In winter oilseed rape field experiments in the 2002/03 and 2003/04 growing seasons, pretreatment with L. biglobosa or ASM in October/November decreased not only the number of phoma leaf spot lesions per leaf caused by L. maculans in autumn/winter, but also the severity of phoma stem canker in the subsequent spring/summer. Effects were greater in 2002/03 (when natural L. maculans ascospore release began in September 2002) than in 2003/04 (when ascospore release began in December following a period of dry weather in August/September 2003). These results suggest that pretreatment with biological or chemical defence activators can induce local and systemic resistance to L. maculans, with both short-term effects on the development of phoma leaf spotting and long-term effects on the development of stem canker 8 months later. [source]

    Effects of temperature and rainfall on date of release of ascospores of Leptosphaeria maculans (phoma stem canker) from winter oilseed rape (Brassica napus) debris in the UK

    Y.J. Huang
    Abstract Data from a controlled environment experiment investigating effects of temperature on maturation of Leptosphaeria maculans pseudothecia were used to derive equations describing the times until 30% or 50% of pseudothecia were mature as a function of temperature. A wetness sensor was developed to estimate the oilseed rape debris wetness and operated with debris exposed in natural conditions in 2000 and 2001. The maturation of L. maculans pseudothecia on debris and concentrations of airborne L. maculans ascospores were observed from 1999 to 2004. There were considerable differences between years, with the first mature pseudothecia observed in September in most years. There were linear relationships between the first date when 10% of maximum ascospore release was observed and the dates when 30% or 50% of pseudothecia were mature. By summing the daily temperature-dependent rate of pseudothecial maturation for days after 1 August with rainfall >0.5 mm, the dates when 30% or 50% of pseudothecia were mature were predicted. There was good agreement between predicted and observed dates when 30% or 50% of pseudothecia were mature. These equations for predicting the timing of L. maculans ascospore release could be incorporated into schemes for forecasting, in autumn, the severity of phoma stem canker epidemics in the following spring/summer in the UK. [source]

    Population growth and mass mortality of an estuarine fish, Acanthopagrus butcheri, unlawfully introduced into an inland lake

    Kimberley Smith
    Abstract 1.In 2006, two periods of hypoxia resulted in the death of approximately 35 tonnes of black bream (Acanthopagrus butcheri) in Lake Indoon, a small inland lake in Western Australia. 2.Acanthopagrus butcheri was the first fish species to be recorded in this lake, along with the mosquitofish (Gambusia holbrooki) which was also observed during sampling in 2006. Acanthopagrus butcheri appears to have been introduced to Lake Indoon between 1998 and 2003 and formed a self-sustaining population. It is believed to have been deliberately introduced for the purpose of creating a recreational fishery, despite the existence of substantial penalties for illegal translocation of fish in Western Australia. 3.Recent human-induced environmental changes, including rising groundwater and salinization, have probably aided the establishment of both species in Lake Indoon. The importance of salinity to recruitment success by A. butcheri was indicated by the presence of only two age classes in 2006, with estimated recruitment dates coinciding with the years of highest recorded salinity in the lake. 4.The ,fish kills' provided an opportunity to examine aspects of A. butcheri biology in a relatively low salinity environment which is atypical for this estuarine species. In particular, the recruitment period in Lake Indoon was delayed until autumn/winter, rather than spring/summer as seen in other populations. Biological responses in Lake Indoon have implications for natural populations living in estuaries with modified salinity regimes. 5.The ecological, social and economic impacts potentially arising from the introduction of fish to Lake Indoon, which is an important migratory bird habitat and a recreational amenity for local residents and tourists, illustrate the complexities of fish translocation and the need for rigorous assessment before stocking to identify potential costs and benefits. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Admission rates of bipolar depressed patients increase during spring/summer and correlate with maximal environmental temperature

    BIPOLAR DISORDERS, Issue 1 2004
    Avraham Shapira
    Objective:, We intended to identify a relationship, if exists, between various climatic factors and the admission rates of bipolar affective disorder depressed patients (BPD) or major depressive disorder patients (unipolar) (UPD) to psychiatric hospitals, as well as potential seasonal variability in hospitalization rates of this population. Methods:, Data on admissions of ICD-9 BPD and UPD patients to Tel Aviv's seven public psychiatric hospitals during 11 consecutive years were collected along with concomitant meteorological information Results:, Admissions of 4117 patients with BPD and 1036 with UPD who fulfilled our specific inclusion criteria were recorded. Bipolar depressed, but not UPD, patients exhibited significant seasonal variation (higher spring and summer versus winter mean monthly admission rates), and the admission rates of patients with BPD, but not UPD, correlated significantly with mean maximal monthly environmental temperature Conclusions:, Increased environmental temperature may be a risk factor for evolvement of major depressive episode in patients with bipolar disorder with psychiatric co-morbidity, at least in cases that necessitate hospitalization and at the examined geographic/climatic region of Israel. Further large-scale studies with bipolar depressed patients with and without co-morbid disorders are needed to substantiate our findings and to determine the role of seasonal and climatic influence on this population, as well as its relationship to the pathophysiology of bipolar disorder. [source]