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Being Lower (being + lower)

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Life Sciences	50%

Selected Abstracts

Air temperature changes in the arctic from 1801 to 1920

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2010
Rajmund Przybylak
Abstract In this paper, the results of an investigation into the thermal conditions in the Arctic in the period from 1801 to 1920 are presented. For this ,early instrumental' period limited meteorological data exist. Generally, the first meteorological stations in the Arctic were established in the second half of the 19th century and almost all of them were located in the coastal parts of Greenland. In order to get at least a rough idea of thermal conditions in the Arctic in the study period, data from different land and marine expeditions were collected. A total of 118 temperature series of monthly means have been gathered. Although the area and time periods covered by the data are variable, it is still possible to describe the general character of the temperature conditions. The results show that the areally averaged Arctic temperature in the early instrumental period was 0.8 °C lower than the next 60-year period (1861,1920). In comparison to present-day conditions, winter and autumn were significantly colder (winter by 1.6 °C and autumn by 0.9 °C) than were summer (colder by 0.4 °C) and spring (colder by only 0.2 °C). The air temperature in the real Arctic during the first International Polar Year (IPY) was, on average, colder than today by 1.0,1.5 °C. Winter was exceptionally cold with the average temperature being lower by more than 3 °C in all months except February. On the other hand, spring (March,May) was slightly warmer than today, and April was exceptionally warm (1.1 °C above present norm). The temperature differences calculated between historical and modern mean monthly temperatures show that majority of them lie within one standard deviation (SD) from present long-term mean. Thus, it means that the climate in the early instrumental period was not as cold as some proxy data suggest. Copyright © 2009 Royal Meteorological Society [source]

Effects of foliar- and root-applied silicon on the enhancement of induced resistance to powdery mildew in Cucumis sativus

PLANT PATHOLOGY, Issue 5 2005
Y. C. Liang
Two cucumber (Cucumis sativus) cultivars differing in their resistance to powdery mildew, Ningfeng No. 3 (susceptible) and Jinchun No. 4 (resistant), were used to study the effects of foliar- and root-applied silicon on resistance to infection by Podosphaera xanthii (syn. Sphaerotheca fuliginea) and the production of pathogenesis-related proteins (PRs). The results indicated that inoculation with P. xanthii significantly suppressed subsequent infection by powdery mildew compared with noninoculation, regardless of Si application. Root-applied Si significantly suppressed powdery mildew, the disease index being lower in Si-supplied than in Si-deprived plants, regardless of inoculation treatment. The resistant cultivar had a more constant lower disease index than the susceptible cultivar, irrespective of inoculation or Si treatment. Moreover, with root-applied Si, activities of PRs (for example peroxidase, polyphenoloxidase and chitinase) were significantly enhanced in inoculated lower leaves or noninoculated upper leaves in inoculated plants of both cultivars. Root-applied Si significantly decreased the activity of phenylalanine ammonia-lyase in inoculated leaves, but increased it in noninoculated upper leaves. However, Si treatment failed to change significantly the activity of PRs in plants without fungal attack. Compared to the control (no Si), foliar-applied Si had no effects either on the suppression of subsequent infection by P. xanthii or on the activity of PRs, irrespective of inoculation. Based on the findings in this study and previous reports, it was concluded that foliar-applied Si can effectively control infections by P. xanthii only via the physical barrier of Si deposited on leaf surfaces, and/or osmotic effect of the silicate applied, but cannot enhance systemic acquired resistance induced by inoculation, while continuously root-applied Si can enhance defence resistance in response to infection by P. xanthii in cucumber. [source]

Fluorene and phenanthrene uptake by Pseudomonas putida ATCC 17514: Kinetics and physiological aspects

BIOTECHNOLOGY & BIOENGINEERING, Issue 3 2005
Ana C. Rodrigues
Abstract Pseudomonas putida ATCC 17514 was used as a model strain to investigate the characteristics of bacterial growth in the presence of solid fluorene and phenanthrene. Despite the lower water-solubility of phenanthrene, P. putida degraded this polycyclic aromatic hydrocarbon (PAH) at a maximum observed rate of 1.4 ± 0.1 mg L,1 h,1, higher than the apparent degradation rate of fluorene, 0.8 ± 0.07 mg L,1 h,1. The role of physiological processes on the biodegradation of these PAHs was analyzed and two different uptake strategies were identified. Zeta potential measurements revealed that phenanthrene-grown cells were slightly more negatively charged (,57.5 ± 4.7 mV) than fluorene-grown cells (,51.6 ± 4.9 mV), but much more negatively charged than glucose-grown cells (,26.8 ± 3.3 mV), suggesting that the PAH substrate induced modifications on the physical properties of bacterial surfaces. Furthermore, protein-to-exopolysaccharide ratios detected during bacterial growth on phenanthrene were typical of biofilms developed under physicochemical stress conditions, caused by the presence of sparingly water-soluble chemicals as the sole carbon and energy source for growth, the maximum value for TP/EPS during growth on phenanthrene (1.9) being lower than the one obtained with fluorene (5.5). Finally, confocal laser microscopy observations using a gfp -labeled derivative strain revealed that, in the presence of phenanthrene, P. putida::gfp cells formed a biofilm on accessible crystal surfaces, whereas in the presence of fluorene the strain grew randomly between the crystal clusters. The results showed that P. putida was able to overcome the lower aqueous solubility of phenanthrene by adhering to the solid PAH throughout the production of extracellular polymeric substances, thus promoting the availability and uptake of such a hydrophobic compound. © 2005 Wiley Periodicals, Inc. [source]

IMPORTANCE OF SLEEP BLOOD PRESSURE

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2008
Trefor Morgan
SUMMARY 1Blood pressure varies throughout the day and night and is maintained at different times by different control systems. 2During the awake interval, the sympathetic nervous system is preeminent but during sleep the renin angiotensin system is the controller. 3Sleep blood pressure is a more powerful predictor of non-haemorrhagic cerebro- and cardiovascular events in animals and humans, despite the sleep value being lower than the day value. 4Drugs that act independently of the hormonal or neural systems, such as diuretics and calcium channel blockers, have similar effects during sleep and awake intervals. Beta-blockers have little effect during sleep when the activity of the sympathetic is low while drugs that interfere with the action of the renin angiotensin system have a greater blood pressure lowering effect during sleep. 5One aim of therapy should be to ensure that blood pressure is low during sleep and drugs should be used in doses that lower blood pressure throughout the 24 h period. [source]