A comparison of the sclerophyllous vegetation characteristic of Mediterranean type climates in France, California, and Southern Australia. II. Dry matter, energy, and nutrient accumulation

1969 ◽  
Vol 17 (2) ◽  
pp. 293 ◽  
Author(s):  
RL Specht
Keyword(s):  
Growth Rate ◽  
Dry Weight ◽  
Minor Role ◽  
Annual Growth Rate ◽  
North West ◽  
Phosphorus And Potassium ◽  
Major Factors ◽  
Vegetation Characteristic ◽  
A Minor ◽  
Sclerophyllous Vegetation

The annual rates of growth (on the basis of dry weight and of solar energy fixed) and nutrient uptakes of garrigue, chaparral, heath, and mallee-broombush growing in the Mediterranean type homoclime of southern France, California, and southern Australia were compared during the first 10 years of succession following fire. The Australian and Californian communities have an essentially similar growth rate of 640-2000 kg/ha/yr. The growth rate of the chaparral may be slightly greater than that of the Australian cominunities owing to greater availability of the nutrients phosphorus and potassium. The application of phosphorus fertilizer will increase the growth rate of Australian heath to that of the chaparral. Observations of Long et al. (1967) made on garrigue 10 km north of Montpellier, France indicate a growth rate of c. 1500 kg/ha/yr, essentially similar to that of the Australian and Californian communities. The author's data for a dense, vigorous stand of garrigue growing on relatively fertile calcareous soil 13 km north-west of Montpellier reveal an annual growth rate of 4000-4200 kg/ha/yr. The growth rates of these distinctive plant communities, composed of entirely different species, are largely controlled by the major factors - solar radiation and available water. In similar homocIimes essentially the same growth rate results. Within limits, soil fertility will play a minor role in controlling the growth rate and consequently the nature of the resultant plant community.

scholarly journals Initial steps of aerosol growth

2004 ◽  
Vol 4 (11/12) ◽  
pp. 2553-2560 ◽  
Author(s):  
M. Kulmala ◽  
L. Laakso ◽  
K. E. J. Lehtinen ◽  
I. Riipinen ◽  
M. Dal Maso ◽  
...  
Keyword(s):  
Growth Rate ◽  
Atmospheric Aerosols ◽  
Minor Role ◽  
Forest Site ◽  
Atmospheric Conditions ◽  
Curvature Effects ◽  
Atmospheric Nucleation ◽  
Condensational Growth ◽  
A Minor ◽  
20 Nm

Abstract. The formation and growth of atmospheric aerosols depend on several steps, namely nucleation, initial steps of growth and subsequent – mainly condensational – growth. This work focuses on the initial steps of growth, meaning the growth right after nucleation, where the interplay of curvature effects and thermodynamics has a significant role on the growth kinetics. More specifically, we investigate how ion clusters and aerosol particles grow from 1.5 nm to 20 nm (diameter) in atmospheric conditions using experimental data obtained by air ion and aerosol spectrometers. The measurements have been performed at a boreal forest site in Finland. The observed trend that the growth rate seems to increase as a function of size can be used to investigate possible growth mechanisms. Such a growth rate is consistent with a recently suggested nano-Köhler mechanism, in which growth is activated at a certain size with respect to condensation of organic vapors. The results also imply that charge-enhanced growth associated with ion-mediated nucleation plays only a minor role in the initial steps of growth, since it would imply a clear decrease of the growth rate with size. Finally, further evidence was obtained on the earlier suggestion that atmospheric nucleation and the subsequent growth of fresh nuclei are likely to be uncoupled phenomena via different participating vapors.

scholarly journals SOME ASPECTS OF THE CULTURE OF EUCHEMA

1970 ◽  
Vol 17 ◽  
pp. 145-146
Author(s):  
U. Horstman ◽  
A. Colina ◽  
W. Schramm
Keyword(s):  
Growth Rate ◽  
The Philippines ◽  
Minor Role ◽  
Bacterial Disease ◽  
Surrounding Water ◽  
Low Salinity ◽  
In Situ Experiments ◽  
Spraying Plants ◽  
A Minor

Eucheuma striatum and Eucheuma spinosum, are red algae of commercial value because of their carrageenin content, to an increasing extent are cultivated in the Philippines. The influence of environmental factors on growth rate and photosynthesis of these seaweeds were studied through observations in their natural biotope in seaweed farms, from in-situ experiments, and photosynthesis experiments in an incubator. While difference in light intensity and temperature play only a minor role, the algae were found out to be sensitive to low salinity and to the amount of dissolved gases and nutrients in the surrounding seawater. The algae can only be cultured in areas where there is sufficient current but to a cer-tain extent lack of current can be compensated by exposing the plants to wave action. This leads to certain conclusions regarding the most suitable method of commercial Eucheuma culture. Eucheuma can be successfully cultured in small rafts or in floating baskets in areas where there is insufficient current for the use of fixed nets or strings. There is evidence that-the CO2 -02 metabolism in the surrounding water plays an important role in Eucheuma growth. Eucheuma harvest can be further increased by introducing more nutrients. Fertilizing with phosphate caused a bigger increase in growth rate than with nitrogen. The method of spraying plants after temporarily removing them from the water, found to be more effective than fertilizing solutions by the use of clay pots. The presence of a bacterial disease, locally referred to as "ice-ice", was recognized as a clear indication that certain environment conditions were unfavourable for Eucheuma culture. Low salinity, in the first place, but also lack of current favors the attack of "ice-ice". Finally, it was found that Eucheuma adapts itself to its culture site in such a way that after maintaining seedlings in an area for a sufficient length of time, the cultured plants showed better growth rates and were resistent to unfavorable conditions than plants recently transferred to the area.

Growth and chemical composition of Townsville lucerne (Stylosanthes humilis). 1. Dry matter yield and nitrogen content in response to superphosphate

1966 ◽  
Vol 6 (21) ◽  
pp. 150 ◽  
Author(s):  
NH Shaw ◽  
CT Gates ◽  
JR Wilson
Keyword(s):  
Nitrogen Content ◽  
Dry Matter ◽  
Nutrient Deficiency ◽  
Dry Weight ◽  
Pot Experiment ◽  
Minor Role ◽  
Dry Matter Yield ◽  
Nutritional Conditions ◽  
Wide Range ◽  
A Minor

In a field experiment on a solodic soil, applications of superphosphate, in the presence of molybdenum, increased the dry matter yield of S. humilis H.B.K. from 2,450 to 5,800 lb an acre, and increased the relative nitrogen content from 2.36 to 3.28 per cent. When this result was examined under more closely controlled conditions in a pot experiment, using the constituent elements of molybdenized superphosphate, it was found that the combination of phosphorus and sulphur produced the greatest dry weight and nitrogen responses. Nevertheless, substantial increases in dry weight of plant tops were obtained with added phosphorus in the absence of sulphur, although the relative nitrogen content of this dry matter was low unless sulphur was also present. There was a small response to molybdenum in this experiment, but calcium played only a minor role. In the pot experiment three replicates were placed in a glasshouse, and one under a light bank in a growth room. Plants grew faster and gave higher dry matter and nitrogen yields under the light bank than in the glasshouse. Attention is drawn to the adaptability that S. humilis displays to a wide range of nutritional conditions, and it is suggested that both the yield and nitrogen content of this legume are probably being limited by nutrient deficiency in most areas of northern Australia where it is being grown.

scholarly journals Heterogeneous mutation rates and spectra within and between species of yeast and their hybrids

2021 ◽  
Author(s):  
Anna Fijarczyk ◽  
Mathieu Hénault ◽  
Souhir Marsit ◽  
Guillaume Charron ◽  
Christian R Landry
Keyword(s):  
Growth Rate ◽  
Natural Selection ◽  
Loss Of Heterozygosity ◽  
Genome Sequencing ◽  
Mutation Accumulation ◽  
Mutation Rates ◽  
Interspecific Crosses ◽  
Minor Role ◽  
Saccharomyces Paradoxus ◽  
A Minor

Mutation rates and spectra vary between species and among populations. Hybridization can contribute to this variation but its role remains poorly understood. Estimating mutation rates requires controlled conditions where the effect of natural selection can be minimized. One way to achieve this is through mutation accumulation experiments coupled with genome sequencing. Here we investigate 400 mutation accumulation lines initiated from 11 genotypes spanning intra-lineage, inter-lineage and interspecific crosses of the yeasts Saccharomyces paradoxus and S. cerevisiae, and propagated for 770 generations. We find significant differences in mutation rates and spectra among crosses, which are not related to the level of divergence of parental strains, but are genotype specific. We find that departures from neutrality, differences in growth rate, ploidy and loss of heterozygosity only play a minor role as a source of variation and conclude that unique combinations of parental genotypes drive distinct rates and spectra in some crosses.

Decreasing Unnecessary Cesarean Section Rate in North West Iran: A Story from Achievements and Challenges

2020 ◽  
Vol 16 (1) ◽  
pp. 23-25
Author(s):  
Sevil Hakimi ◽  
Fariba Nikan ◽  
Behzad Sarvaran Mahram ◽  
Khadijeh Pazani ◽  
Asiyeh Gasempour ◽  
...  
Keyword(s):  
Growth Rate ◽  
Cesarean Section ◽  
Feedback System ◽  
Annual Growth Rate ◽  
Continuous Education ◽  
North West ◽  
High Prevalence ◽  
Main Factors ◽  
East Azerbaijan ◽  
The University

Background: Cesarean section trend has been rising steadily at an alarming rate worldwide, from 6.7 in 1990 to 19.1 in 2014. Objective: The aim of this study was to reduce the high prevalence of Cesarean Section in Iran including North West of country. Method: This study was conducted, using special package provided by the ministry of health (MOH) to reduce unnecessary CS rate in the university-affiliated hospitals in East Azerbaijan province. Results: The average annual growth rate of decreasing primary cesarean section (CS) varied from 2 to 9% in 2013-2017. Conclusion: Holding training classes, continuous education for midwives and the establishment of a feedback system to obstetricians were found to be among the main factors bringing about the success in eliminating unnecessary CS in the present study. The program might prove to be even more successful through increasing cooperation between obstetricians and anesthesiologists.

An experimental study of competitive interference between Anigozanthos manglesii D. Don, A. humilis Lindl. and their F1 Hybrids (Haemodoraceae)

1978 ◽  
Vol 26 (6) ◽  
pp. 807 ◽  
Author(s):  
SD Hooper
Keyword(s):  
Experimental Study ◽  
Competitive Interactions ◽  
F1 Hybrids ◽  
Minor Role ◽  
Naturally Occurring ◽  
Competitive Interference ◽  
Competitive Disadvantage ◽  
Major Factors ◽  
A Minor ◽  
Hybrid Distribution

Poor competitive ability has been invoked often to explain the confinement of hybrids to disturbed ecotones at the junction of parental habitats. This hypothesis has not as yet been verified in an experimental study. Two-month-old seedlings of Anigozanthos manglesii, A, humilis and synthesized F1 hybrids were grown singly and in various paired combinations in small pots for 172 days to test for competitive interactions. F1 hybrids and A. manglesii performed comparably in most competition trials, while A. humilis suffered a considerable competitive disadvantage. It is proposed that competitive interactions may play a minor role in confining naturally occurring F1 hybrids to ecotonal areas between habitats preferentially occupied by A. humilis and A. manglesii. Spatial limitations on pollen and seed flow appear to be the major factors controlling hybrid distribution in this case.

scholarly journals Demographic Theory and Population Ethics – Relationships between Population Size and Population Growth

2021 ◽  
Author(s):  
Martin Kolk
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Size ◽  
Well Being ◽  
Minor Role ◽  
Population Ethics ◽  
Working Paper ◽  
Size Population ◽  
Demographic Theory ◽  
A Minor

Demographic theory aims at explaining how population systems regulate themselves given available resources. Population ethics is concerned with demography in the sense that the analytical objects of interest are births, deaths, and populations. However, demographic theory which explores theoretically when, how and why populations grow, based on empirically observed patterns, has up until now played a minor role in population ethics. Similarly, debates about population dynamics among demographers have seldom been concerned with ideas and concepts in population ethics. In this manuscript, I will give a brief outline of how population size, population growth, and welfare mutually affect each other. Theories on the endogeneity between population size, population growth, and welfare will be referred to as demographic theory. I will give a particular focus on how population growth responds with respect to welfare, as welfare, utility, well-being, and happiness are important concepts in population ethics. A key concept in demographic theory is population homeostasis (the dynamics of a system which maintains a population at a steady population size, or growth rate), in particular resource dependent homeostasis. I will also discuss demographic theory in relation to historical and future demographic change. This working paper was later published in Oxford Handbook of Population Ethics, and is available at https://osf.io/preprints/socarxiv/at5pj/

scholarly journals Spread of infectious disease through clustered populations

2009 ◽  
Vol 6 (41) ◽  
pp. 1121-1134 ◽  
Author(s):  
Joel C. Miller
Keyword(s):  
Infectious Disease ◽  
Growth Rate ◽  
Significant Contribution ◽  
Dominant Factor ◽  
Disease Models ◽  
Minor Role ◽  
Rate Heterogeneity ◽  
A Minor ◽  
The Impact ◽  
Infectious Disease Models

Networks of person-to-person contacts form the substrate along which infectious diseases spread. Most network-based studies of this spread focus on the impact of variations in degree (the number of contacts an individual has). However, other effects such as clustering, variations in infectiousness or susceptibility, or variations in closeness of contacts may play a significant role. We develop analytic techniques to predict how these effects alter the growth rate, probability and size of epidemics, and validate the predictions with a realistic social network. We find that (for a given degree distribution and average transmissibility) clustering is the dominant factor controlling the growth rate, heterogeneity in infectiousness is the dominant factor controlling the probability of an epidemic and heterogeneity in susceptibility is the dominant factor controlling the size of an epidemic. Edge weights (measuring closeness or duration of contacts) have impact only if correlations exist between different edges. Combined, these effects can play a minor role in reinforcing one another, with the impact of clustering the largest when the population is maximally heterogeneous or if the closer contacts are also strongly clustered. Our most significant contribution is a systematic way to address clustering in infectious disease models, and our results have a number of implications for the design of interventions.

scholarly journals Upper layer current variability in the Central Ligurian Sea

Ocean Science ◽  
2010 ◽  
Vol 6 (4) ◽  
pp. 825-836 ◽  
Author(s):  
P. Picco ◽  
A. Cappelletti ◽  
S. Sparnocchia ◽  
M. E. Schiano ◽  
S. Pensieri ◽  
...  
Keyword(s):  
Water Column ◽  
General Circulation ◽  
Minor Role ◽  
Time Interval ◽  
Mean Velocity ◽  
Ligurian Sea ◽  
Near Surface ◽  
North West ◽  
Long Time ◽  
A Minor

Abstract. Long-time series of surface currents and meteorological parameters were analysed to estimate the variability of the upper layer circulation and the response to the local winds. Current meter data were collected by an upward-looking RDI Sentinel 300 kHz ADCP deployed in the Central Ligurian Sea (43°47.77' N; 9°02.85' E) near the meteo-oceanographic buoy ODAS Italia 1 for more than eight months, from 13th of September 2003 to 24th of May 2004. The ADCP sampled the upper 50 m of water column at 8 m vertical resolution and 1 h time interval; surface marine and atmospheric hourly averaged data were provided by the buoy. Currents in the sampled layer were mainly barotropic, directed North-West in accordance with the general circulation of the area, and had a mean velocity of about 18 cm/s and hourly mean peaks up to 80 cm/s. Most of the observed variability in the upper thermocline was determined by inertial currents and mesoscale activity due to the presence of the Ligurian Front. Local wind had a minor role in the near-surface circulation but induced internal waves propagating downward in the water column.

Neonatal Cellular and Humoral Immunity to Group B Streptococci

PEDIATRICS ◽  
1979 ◽  
Vol 64 (5) ◽  
pp. 787-794
Author(s):  
Harry R. Hill ◽  
Ann O. Shigeoka ◽  
Robert T. Hall ◽  
Val G. Hemming
Keyword(s):  
Bacterial Infections ◽  
Metabolic Activation ◽  
Minor Role ◽  
Complement Pathway ◽  
Group B Streptococci ◽  
Opsonic Activity ◽  
Bacterial Uptake ◽  
Group B ◽  
Major Factors ◽  
A Minor

The mechanisms of host resistance to group B streptococci have not been defined precisely. In the studies reported here we have assessed the contributions of both humoral and cellular factors in protection against strains of this group. With assays of specific opsonic activity based upon the production of polymorphonuclear leukocyte chemiluminescence and radiolabeled bacterial uptake, we have demonstrated that specific heat-stable antibody and the classic complement pathway are major factors in opsonization of these organisms. In the absence of specific antibody, fresh serum resulted in markedly reduced bacterial uptake indicating, at best, a minor role for the alternative complement pathway. Additional studies have indicated that strain-specific antiphagocytic factors as well as type-specific ones may play a role in the virulence of these organisms. Neonates who developed group B streptococcal sepsis usually lacked opsonic activity in their infecting strain. In addition, polymorphonuclear leukocytes from normal term and stressed neonates showed impaired metabolic activation as measured in the chemiluminescence assay following exposure to opsonized group B streptococci. These results suggest that neonates who develop group B streptococcal disease may have defects in both the humoral and cellular aspects of their acute inflammatory response which may contribute to the high mortality observed in this most fulminant of bacterial infections.

Sign in / Sign up

Export Citation Format

Share Document