Periodicities in geomagnetic-activity indices and solar-wind parameters, and their possible solar origin

We have examined the average behaviors of the solar-wind parameters and the geomagnetic-activity indices. There is a good correlation between the increasing pressure at the magnetopause and the intense magnetospheric disturbances. The ultra-low frequency power spectra for the geomagnetic disturbances have been analyzed and tested. Although the spectrum shows remarkable and stable peaks at the wavelengths 0.5, 0.7, 1.0, 1.3 years, additional significant peaks of 73 d, 1.5 y, 5.1 y and 9.2 y for Ap and 73 d and 1.4 y for the product BSV 2 are also found. However, the 73-d and 5.1-y variations correspond to a non-obvious physical process in the Sun. The Sun may reflect some irregular variations, basically not fundamental, which appear at different times. A comparison of both spectra for periods > 0.5 year suggests different solar origins. Both spectra have different power amplitudes and peaks at different locations. Our study confirmed 1.4–1.5 year oscillations in BSV 2 measurements between 1987 and 2000, and located slightly higher than the Kp peaks (∼ 1.3 y). Although many papers have discussed periodicities in the Ap index, a 9.2-year period has not been reported previously. There is some indication of an association with the coronal-hole variations in the southern hemisphere of the Sun. The conjunction of the Sun observations and SW measurements may be used to estimate the disturbances in the geomagnetic activity in the heliosphere

North-South asymmetry of cosmic-ray density gradients throughout the epoch 1955-1991

We have computed the magnitude and direction of the asymmetry of cosmic-ray particle density gradient in the heliosphere during the period 1955-1991. Data obtained by twenty-one detectors (neutron monitors, surface and underground muon telescopes) in both terrestrial hemispheres between 1955 and 1991 are analyzed as a function of the sense of interplanetary magnetic field. Their median rigidity of response (Rm) covers the following range: 10 GV � Rm � 185 GV. Significant differences are frequently observed between the diurnal variations measured in toward and away polarity days. The cosmic-ray density gradient displayed insignificant changes near solar maxima and reversed in sign after the reversal polarity periods. The resultant cosmic-ray gradients are: a north-south symmetric gradient which occurred during minima and maxima solar activity epochs, and a N-S asymmetrical gradient which is related to the N-S asymmetry in the activity on the Sun. Northward and southward cosmic-ray latitudinal (or perpendicular) gradients were frequently observed. The solar diurnal phases of toward polarity days north of the HCS (or away) during the period 1981-87 (qA < 0) existed a few hours later than those recorded for toward (or away) days south of HCS during the positive IMF period 1971-78, as well as the time shift depends on the rigidity of the particle. In addition, quite a change occurred on phase for the north neutron monitors and muon telescopes than for those located on the southern hemisphere

Studying of the Solar-Climate Interaction in Canada

Abstract It is well known that the solar radiation output changes periodically and also that it affects the Earth and near-space environment in various ways. The Earth climate system has shown irregular changes during the second half of the 20th century, especially for the last four decades. The scientific and public discussions about the influence of the solar radiation on global warming are still ongoing. It is obvious that the man-made gases (e.g., the concentration of carbon dioxide in the atmosphere was never as high during the last thousand years as it is today) is an important factor affecting the Earth&apos;s surface temperature, but it may be not the only one. The present work presents a correlative study to investigate the possible effect of some geomagnetic and solar parameters on climate variability of global temperature represented by the temperature of Canada. Two components (monthly averages) that may be closely associated with the climate have been studied, which are the geomagnetic activity, aa and the sunspot number, Rz throughout a long period of 114 years from

Solar and Geomagnetic Activity Effects on Global Surface Temperatures

Abstract It is a clear fact that the Earth&apos;s climate has been changing since the pre-industrial era, especially during the last three decades. This change is generally attributed to two main factors: greenhouse gases (GHGs) and solar activ ity changes. However, these factors are not all-independent. Furthermore, contributions of the above-mentioned factors are still d isputed. The aim of th is paper is relation in the longer t ime , between changer of g lobal surface temperature (GST), and solar geomagnetic activ ist represented by sunspot number (Rz) and geomagnetic indices (aa , Kp ), and to what degree they are connected. The geomagnetics aa are more effect ive on global surface temperature than solar activity. Furthermore, the global surface temperature are strongly sensitive to the 21.3-yr, 10.6-yr, and 5.3-yr variations that observed in the considered geomagnetic and sunspot spectra. The present changes in aa geo magnetics may reflect part ially some future changes in the global surface temperatures

Agronomic Management of Indigenous Mycorrhizas

Many of the advantages conferred to plants by arbuscular mycorrhiza (AM) are associated to the ability of AM plants to explore a greater volume of soil through the extraradical mycelium. Sieverding (1991) estimates that for each centimetre of colonized root there is an increase of 15 cm3 on the volume of soil explored, this value can increase to 200 cm3 depending on the circumstances. Due to the enhancement of the volume of soil explored and the ability of the extraradical mycelium to absorb and translocate nutrients to the plant, one of the most obvious and important advantages resulting from mycorrhization is the uptake of nutrients. Among of which the ones that have immobilized forms in soil, such as P, assume particular significance. Besides this, many other benefits are recognized for AM plants (Gupta et al, 2000): water stress alleviation (Augé, 2004; Cho et al, 2006), protection from root pathogens (Graham, 2001), tolerance to toxic heavy metals and phytoremediation (Audet and Charest, 2006; Göhre and Paszkowski, 2006), tolerance to adverse conditions such as very high or low temperature, high salinity (Sannazzaro et al, 2006), high or low pH (Yano and Takaki, 2005) or better performance during transplantation shock (Subhan et al, 1998). The extraradical hyphae also stabilize soil aggregates by both enmeshing soil particles (Miller e Jastrow, 1992) and producing a glycoprotein, golmalin, which may act as a glue-like substance to adhere soil particles together (Wright and Upadhyaya, 1998). Despite the ubiquous distribution of mycorrhizal fungi (Smith and Read, 2000) and only a relative specificity between host plants and fungal isolates (McGonigle and Fitter, 1990), the obligate nature of the symbiosis implies the establishment of a plant propagation system, either under greenhouse conditions or in vitro laboratory propagation. These techniques result in high inoculum production costs, which still remains a serious problem since they are not competitive with production costs of phosphorus fertilizer. Even if farmers understand the significance of sustainable agricultural systems, the reduction of phosphorus inputs by using AM fungal inocula alone cannot be justified except, perhaps, in the case of high value crops (Saioto and Marumoto, 2002). Nurseries, high income horticulture farmers and no-agricultural application such as rehabilitation of degraded or devegetated landscapes are examples of areas where the use of commercial inoculum is current. Another serious problem is quality of commercial available products concerning guarantee of phatogene free content, storage conditions, most effective application methods and what types to use. Besides the information provided by suppliers about its inoculum can be deceiving, as from the usually referred total counts, only a fraction may be effective for a particular plant or in specific soil conditions. Gianinazzi and Vosátka (2004) assume that progress should be made towards registration procedures that stimulate the development of the mycorrhizal industry. Some on-farm inoculum production and application methods have been studied, allowing farmers to produce locally adapted isolates and generate a taxonomically diverse inoculum (Mohandas et al, 2004; Douds et al, 2005). However the inocula produced this way are not readily processed for mechanical application to the fields, being an obstacle to the utilization in large scale agriculture, especially row crops, moreover it would represent an additional mechanical operation with the corresponding economic and soil compaction costs. It is well recognized that inoculation of AM fungi has a potential significance in not only sustainable crop production, but also environmental conservation. However, the status quo of inoculation is far from practical technology that can be widely used in the field. Together a further basic understanding of the biology and diversity of AM fungi is needed (Abbott at al, 1995; Saito and Marumoto, 2002). Advances in ecology during the past decade have led to a much more detailed understanding of the potential negative consequences of species introductions and the potential for negative ecological consequences of invasions by mycorrhizal fungi is poorly understood. Schwartz et al, (2006) recommend that a careful assessment documenting the need for inoculation, and the likelihood of success, should be conducted prior to inoculation because inoculations are not universally beneficial. Agricultural practices such as crop rotation, tillage, weed control and fertilizer apllication all produce changes in the chemical, physical and biological soil variables and affect the ecological niches available for occupancy by the soil biota, influencing in different ways the symbiosis performance and consequently the inoculum development, shaping changes and upset balance of native populations. The molecular biology tools developed in the latest years have been very important for our perception of these changes, ensuing awareness of management choice implications in AM development. In this context, for extensive farming systems and regarding environmental and economic costs, the identification of agronomic management practices that allow controlled manipulation of the fungal community and capitalization of AM mutualistic effect making use of local inoculum, seem to be a wise option for mycorrhiza promotion and development of sustainable crop production

Diagnostic accuracy of a clinical diagnosis of idiopathic pulmonary fibrosis: An international case-cohort study

We conducted an international study of idiopathic pulmonary fibrosis (IPF) diagnosis among a large group of physicians and compared their diagnostic performance to a panel of IPF experts. A total of 1141 respiratory physicians and 34 IPF experts participated. Participants evaluated 60 cases of interstitial lung disease (ILD) without interdisciplinary consultation. Diagnostic agreement was measured using the weighted kappa coefficient (\u3baw). Prognostic discrimination between IPF and other ILDs was used to validate diagnostic accuracy for first-choice diagnoses of IPF and were compared using the Cindex. A total of 404 physicians completed the study. Agreement for IPF diagnosis was higher among expert physicians (\u3baw=0.65, IQR 0.53-0.72, p20 years of experience (C-index=0.72, IQR 0.0-0.73, p=0.229) and non-university hospital physicians with more than 20 years of experience, attending weekly MDT meetings (C-index=0.72, IQR 0.70-0.72, p=0.052), did not differ significantly (p=0.229 and p=0.052 respectively) from the expert panel (C-index=0.74 IQR 0.72-0.75). Experienced respiratory physicians at university-based institutions diagnose IPF with similar prognostic accuracy to IPF experts. Regular MDT meeting attendance improves the prognostic accuracy of experienced non-university practitioners to levels achieved by IPF experts