8,188 research outputs found

    The Effects of Different Intensity of Thinning on the Development in Scots Pine (Pinus sylvestris L.) Stands in Kazakh Uplands

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    The search for more accurate methods of predicting the growth and development of forest stands became the most urgent task set for foresters of Kazakhstan to determine the permissible interventions in the natural course of the life of plantings, provide high durability and resilience in forests. The aim of the study was to identify the effects of diameter and density of Scots pine stands of Kazakh Uplands on their growth and productivity and the related productivity of single plantation stands taking into account the conditions of growth and development of internal factors as well as further study of the methodology for assessing the forestry cost-effectiveness and improvement thinning. To achieve this aim, effects of varied felling intensities on Scots pine stands were studied. The most common two forest types in upland Scots pine forests were chosen as permanent sample plots; the dead pine-lichen and moss pine-grass. The results showed that improvement thinning of moderate and severe intensity which are more profitable should be done in Scots pine forests of Kazakh Upland as well as carrying out such thinning increases the yield of the larger logs and increases the value of the left stand

    Relative and individual regulation: An investigation of investment incentives under a cost-plus approach

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    We analyze the effects of a modified Yardstick competition on firms’ cost-reduction efforts. Departing from the existing literature, we use a relative cost-plus approach: firms are regulated on the basis of other firms’ performances, but they are granted a mark-up and not a lump-sum transfer in order to be compensated for their investments. We show that the cost-reduction effort of a regulated firm is decreasing in the mark-up under relative regulation while it is increasing in the mark-up under individual regulation. Hence, the trade-off between encouraging cost reduction and minimizing prices that the regulator faces under individual cost-plus regulation does not exist under relative cost-plus regulation. We extend our model by including technical spillovers and we investigate their effects on firms’ cost reduction efforts and on the efficiency of the whole industry. Finally, we allow for quality-enhancing investments and study the interplay between them and cost reduction investments under relative cost-plus regulation.Yardstick Competition, Cost Reduction, Cost-Plus Regulation

    The QBO and weak external forcing by solar activity: A three dimensional model study

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    A better understanding is attempted of the physical mechanisms leading to significant correlations between oscillations in the lower and middle stratosphere and solar variability associated with the sun's rotation. A global 3-d mechanistic model of the middle atmosphere is employed to investigate the effects of minor artificially induced perturbations. The aim is to explore the physical mechanisms of the dynamical response especially of the stratosphere to weak external forcing as it may result from UV flux changes due to solar rotation. First results of numerical experiments dealing about the external forcing of the middle atmosphere by solar activity were presented elsewhere. Different numerical studies regarding the excitation and propagation of weak perturbations have been continued since then. The model calculations presented are made to investigate the influence of the quasi-biennial oscillation (QBO) on the dynamical response of the middle atmosphere to weak perturbations by employing different initial wind fields which represent the west and east phase of the QBO

    Bioactive secondary metabolites from the endophytic fungus Chaetomium sp. isolated from Salvia officinalis growing in Morocco

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    This study reports the chemical investigation and cytotoxic activity of the secondary metabolites produced by the endophytic fungus Chaetomium sp. isolated from Salvia officinalis growing in Morocco. This plant was collected from the Beni-Mellal Mountain in Morocco and belongs to the Lamiaceae family and is named in Morocco 'Salmia'. The endophytic fungus Chaetomium sp. was isolated from the tissues of the stem of this plant. The fungal strain was identified by PCR. The crude organic extract of the fungal strain was proven to be active when tested for cytotoxicity against L5178Y mouse lymphoma cells. Chemical investigation of the secondary metabolites showed that cochliodinol is the main component beside isocochliodinol. The structures of the isolated compounds were determined on the basis of NMR analysis (1H, 13C, COSY and HMBC) as well as by mass spectrometry using ESI (Electron Spray Ionisation) as source

    On the measurement and impact of fiscal decentralization

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    The typical post-Bretton Woods era development approach that emphasized central government-led development efforts has changed dramatically, and local governments have clearly emerged as players in development policy. The thinking about what is important to achieve in development objectives is changing as fiscal decentralization reforms are being pursued by many countries around the world. In this context, a number of studies have attempted to quantify the impact of decentralization by relating some measure of it to economic outcomes of fiscal stability, economic growth, and public sector size. But decentralization is surprisingly difficult to measure. Nearly all cases examining the relationship between decentralization and macroeconomic performance have relied on the Government Finance Statistics (GFS) of the International Monetary Fund. However, despite its merits, GFS falls short in providing a full picture of fiscal decentralization. For some countries, however, there is data that more accurately captures fiscal responsibilities among different types of governments.Decentralization,Banks&Banking Reform,Municipal Financial Management,Public&Municipal Finance,Public Sector Economics&Finance,National Governance,Public Sector Economics&Finance,Banks&Banking Reform,Municipal Financial Management,Urban Economics

    Nuclear structure calculations for neutron-star crusts

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    The goal of this paper is to investigate properties of clusterized nuclear matter which is believed to be present in crusts of neutron stars at subnuclear densities. It is assumed that the whole system can be represented by the set of Wigner-Seitz cells, each containing a nucleus and an electron background under the condition of electroneutrality. The nuclear structure calculations are performed within the relativistic mean-field model with the NL3 parametrization. The first set of calculations is performed assuming the constant electron background. The evolution of neutron and proton density distributions was systematically studied along isotopic chains until very neutron-rich system beyond the neutron dripline. Then we have replaced the uniform electron background with the realistic electron distributions, obtained within the Thomas-Fermi approximation in a self-consistent way with the proton distributions. Finally, we have investigated the evolution of the β\beta-stability valley as well as neutron and proton driplines with the electron density.Comment: 21 pages, 14 figure

    Natural product diversity of actinobacteria in the Atacama Desert

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    Natural Product diversityPeer reviewedPublisher PD

    Horizontal wind perturbations and their relation to transient internal gravity waves

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    Horizontal winds as measured with the Saskatoon MF radar exhibit wind fluctuations which have preferred directions toward north or south in the period range 0 to 60 min at heights between about 60 and 110 km. Longer period perturbations (approx 1-6 h) tend to have an additional maximum of direction frequencies in the E-W sector.The polarization effect analyzed for more than 6 years shows regular changes with season. The main features of the seasonal variations of the direction distributions can be explained by directional filtering of vertically propagating nonstationary gravity waves and appropriate changes of the wave source strength and position in the troposphere. The N-S polarization of the gravity-wave field appears to result in meridional wind reversals with height above the mesopause