THE pH OF NON-CALCAREOUS NEAR-NEUTRAL SOILS

Nichol, W. E.

doi:10.4141/cjss57-015

Cited by 16 publications

(8 citation statements)

References 2 publications

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“…Uncertainties in the description of the IGM evolution (both its normalization, f g0 ∼ 0.1 ÷ 0.3 at the scale of rich clusters, and its evolution with time parametrized in terms of the parameters η ∼ 0 ÷ 0.9 and s ∼ 0 ÷ 1.5) are discussed to point out the role of different, possible gas-phase phenomena in cluster evolution. Here we take into account the minimal and maximal levels of IGM evolution that are still consistent -given the observational uncertainties -with the current data ([65] [25] [26] [28]).…”

Section: The Contribution Of Galaxy Clusters To the Dgrbmentioning

confidence: 99%

Clusters of galaxies and the diffuse gamma-ray background

Colafrancesco¹,

Blasi²

1998

Astroparticle Physics

164

209

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We discuss the diffuse emission of gamma rays and neutrinos from galaxy clusters in the viable models for structure formation in the universe. We use a self-consistent picture for cluster formation and evolution starting from a primordial density perturbation spectrum, and a realistic modelling for the distribution of the intergalactic medium which is abundantly present within galaxy clusters. We find that an evolving population of clusters can produce a fraction ∼ 0.5 ÷ 2% of the diffuse gamma-ray background (DGRB) observed by EGRET. This result is robust and is weakly dependent on the cosmological scenario and on the degree of evolution of the inter galactic medium (IGM) in distant clusters, because the bulk of the sources contributing to the DGRB is located at redshifts z ∼ < 0.2. We also found a correlation between the non-thermal, gamma-ray and the thermal X-ray emissions from these structures. Using this result, we derived a list of gamma-ray clusters observable with the next generation γ-ray detectors. Finally, we briefly discuss the possible relevance of galaxy clusters for neutrino astronomy and for very high energy particle astronomy.

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Section: The Contribution Of Galaxy Clusters To the Dgrbmentioning

confidence: 99%

Clusters of galaxies and the diffuse gamma-ray background

Colafrancesco¹,

Blasi²

1998

Astroparticle Physics

164

209

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“…Gorham (1960) found that aeration of wet soils increased pH by reducing the tension of respired carbon dioxide. Nichol and Turner (1957) discussed the difficulties of interpreting the results of laboratory pH measurements of soils, pointing out that none of the methods gives results which can be directly related to field conditions. Humus pH is highest in midsummer and decreases as winter approaches, indicating that decreasing soil temperature decreases chemical and biological activity and causes decreases in soil pH.…”

Section: Resultsmentioning

confidence: 99%

“…However, the seasonal distribution of rainfall did not correspond to seasonal changes in humus reaction in this study. Nichol and Turner (1957) discussed the difficulties of interpreting the results of laboratory pH measurements of soils, pointing out that none of the methods gives results which can be directly related to field conditions. Gorham (1960) reported the range of pH values obtained from different humus types by three methods, i.e., insertion of glass electrodes into soil, into expressed solutions, and into aerated solutions.…”

Section: Resultsmentioning

confidence: 99%

Methods of pH Determination and Seasonal pH Fluctuations in Quebec Forest Humus

Vezina¹

1965

Ecology

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Seasonal fluctuations of humus pH of three commonly occurring forest soils in Quebec were assessed to determine which of four different methods was best suited for comparisons of pH among sites. Seasonal variations of 1.1 to 1.3 units were observed on all soil types tested. Humus pH was highest in midsummer and decreased as winter approached. Different pH values were obtained from the same soil at the same time by the different methods used. Reproducibility of pH measurements is briefly discussed.

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“…In a previous publication (4) was independent of the salt concentration. Table 3 shows that the pH increased as the soil/water ratio was decreased, but that pH-|pCa, pMg-pCa and pH-!p(Ca*MS) were independent of the ratio.…”

Section: Introductionmentioning

confidence: 98%