نتایج جستجو برای: late autumn frost

تعداد نتایج: 210182  

2014
Gilbert Neuner

This report provides a brief review of key findings related to frost resistance in alpine woody plant species, summarizes data on their frost resistance, highlights the importance of freeze avoidance mechanisms, and indicates areas of future research. Freezing temperatures are possible throughout the whole growing period in the alpine life zone. Frost severity, comprised of both intensity and d...

2013
Arne Schröder

Winter processes such as overwinter survival and growth of individuals can have wide-ranging consequences for population dynamics and communities within and across seasons. In freshwater organisms winter processes have been mainly studied in fish despite that invertebrates also have substantial impacts on lake and pond food webs. One of the major invertebrate consumers in lake and ponds is the ...

2017
Stephen W. Hoffman Jeff P. Smith STEPHEN W. HOFFMAN JEFF P. SMITH

Trained observers counted migrating raptors and vultures from ridgetops at six sites in the Intermountain and Rocky Mountain Flyways of western North America: Goshute Mountains, Nevada (autumn 1983–2001); Wellsville Mountains, Utah (autumn 1977–1979 and 1987–2001); Bridger Mountains, Montana (autumn 1992–2001); Manzano Mountains, New Mexico (autumn 1985–2001); Sandia Mountains, New Mexico (spri...

2008
Birgitte I. McDonald Daniel E. Crocker Jennifer M. Burns Daniel P. Costa

Body composition is a direct measure of body condition and as such integrates seasonal variation in foraging success and energy expenditure. In phocids, body condition is a critical determinant of both reproductive effort and ability to survive periods of poor foraging success. We determined body composition in 29 crabeater seals, Lobodon carcinophaga, during austral autumn (April–May 2002) and...

2005
Joseph M. Dirnberger Jason Weinberger

Dirnberger, J. M. and J. Weinberger. 2005. Influences of lake level changes on reservoir water clarity in Allatoona Lake, Georgia. Lake and Reserv. Manage. Vol. 21(1):24-29. In Allatoona Lake (Georgia USA), secchi transparency (measured every 2 to 4 weeks during a Phase I U.S. EPA Clean Lakes Study) was typically 5to 8fold greater in summer than late autumn and winter. The intensity of storms i...

Journal: :Journal of agricultural and food chemistry 2000
B de Ancos E M González M P Cano

The ellagic acid, total phenolic, and vitamin C contents in four raspberry cultivars (Heritage, Autumn Bliss, Rubi, and Zeva) grown in Spain were detected and quantified by HPLC in fresh, just frozen, and stored fruits at -20 degrees C for a one year period. Ellagic acid [207-244 mg kg(-)(1) of fresh weight (fw)], total phenolic (137-1776 mg kg(-)(1) of fw), and vitamin C (221-312 mg kg(-)(1) o...

2006
V. Aaltonen H. Lihavainen

Three years of continuous measurements of aerosol optical properties and simultaneous aerosol number size distribution measurements at Pallas GAW station, a remote subarctic site in the northern border of the boreal forest zone, have been analysed. The scattering coefficient at 550 nm varied from 0.2 to 94.4 Mm−1 with an average of 7.1±8.6 Mm−1. Both the scattering and backscattering coefficien...

2012
D. W. Johnston A. S. Friedlaender A. J. Read D. P. Nowacek

In the Southern Ocean, humpback whales Megaptera novaeangliae were depleted by commercial whaling operations during the 20th century, but many populations now appear to be recovering. Previous surveys of whale distribution along the western Antarctic Peninsula (WAP) suggested that humpbacks feed on krill swarms over the continental shelf during the summer, but little is known about their moveme...

2010
Christina Kaiser Marianne Koranda Barbara Kitzler Lucia Fuchslueger Jörg Schnecker Peter Schweiger Frank Rasche Sophie Zechmeister-Boltenstern Angela Sessitsch Andreas Richter

*Plant seasonal cycles alter carbon (C) and nitrogen (N) availability for soil microbes, which may affect microbial community composition and thus feed back on microbial decomposition of soil organic material and plant N availability. The temporal dynamics of these plant-soil interactions are, however, unclear. *Here, we experimentally manipulated the C and N availability in a beech forest thro...

2015
Rachel Anderson Peter Ryser

Several theories exist about the role of anthocyanins in senescing leaves. To elucidate factors contributing to variation in autumn leaf anthocyanin contents among individual trees, we analysed anthocyanins and other leaf traits in 27 individuals of red maple (Acer rubrum L.) over two growing seasons in the context of timing of leaf senescence. Red maple usually turns bright red in the autumn, ...

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