Morse potential energy spectra through the variational method and supersymmetry

The Variational Method is applied within the context of Supersymmetric Quantum Mechanics to provide information about the energy and eigenfunction of the lowest levels of a Hamiltonian. The approach is illustrated by the case of the Morse potential applied to several diatomic molecules and the results are compared with stablished results.Comment: 9 pages, LATEX, 1 eps figur

Supersymmetric variational energies for the confined Coulomb system

The methodology based on the association of the Variational Method with Supersymmetric Quantum Mechanics is used to evaluate the energy states of the confined hydrogen atom.Comment: 9 pages, Latex, version to appear in Phys. Lett. A299 (2002) 137-14

Supersymmetric variational energies of 3d confined potentials

Within the approach of Supersymmetric Quantum Mechanics associated with the variational method a recipe to construct the superpotential of three dimensional confined potentials in general is proposed. To illustrate the construction, the energies of the Harmonic Oscillator and the Hulth\'en potential, both confined in three dimensions are evaluated. Comparison with the corresponding results of other approximative and exact numerical results is presented.Comment: 9 pages, Late

Approximate solution for Fokker-Planck equation

In this paper, an approximate solution to a specific class of the Fokker-Planck equation is proposed. The solution is based on the relationship between the Schr\"{o}dinger type equation with a partially confining and symmetrical potential. To estimate the accuracy of the solution, a function error obtained from the original Fokker-Planck equation is suggested. Two examples, a truncated harmonic potential and non-harmonic polynomial, are analyzed using the proposed method. For the truncated harmonic potential, the system behavior as a function of temperature is also discussed.Comment: 12 pages, 8 figure

Community-based forest management plans in the Brazilian Amazon: Current barriers and necessary reforms

Community-based forest management (CBFM) projects are often seen as an alternative to protect forest and at the same time to provide incomes for small landholders. Since the mid-1990s, the number of CBFM projects has increased in the Brazilian Amazon although most of them face several difficulties despite significant public support. Four CBFM plans were analyzed between 2005 and 2009 to assess the main barriers threatening their long term viability. Two plans are located in the State of Acre (Porto Dias Association and APRUMA) and two in the State of Para (Virola Jatoba Association and CANOR Cooperative). The first important barrier to successfully implementation of CBFM is the complex legal framework: it currently takes at least 2 to 3 years to get a plan approved. Public regulations and institutions have to become more efficient. Moreover management plan elaboration process is costly. None of the CBFM plan could have been successfully implemented without external national and international financial supports, as well as technical assistance. Finally, in the current Amazonian market context, timber harvest only represents a limited complementary income for small farmers, even if forest covers 80 % of their landholding. Market access is very uncertain and small holders communities do not systematically succeed in selling their timber at remunerative prices. Minimum remunerative public prices should be guaranteed for timber from such CBFM plans to make them a truly economic alternative for the Amazon smallholders. (Résumé d'auteur

Shaping the implementation of the FSC standard: the case of auditors in Brazil

The Forest Stewardship Council (FSCJ label is one of t he most robust and widely accepted standards aimed at assessing long-term sustainable forest management worldwide. Through audits, accredited certification bodies assess the level or conformity of a company's performance against the standard to grant or not the certificate on behalf of the FSC. In this paper, we assess the scope auditors have to shape the implementation of the FSC standard in Brazil. Our work is based on the analysis of certification bodies· rules and of 250 full assessment and annual audit reports covering the period 2005-2017. including native and plantations reports. All reports were publicly available on FSC database. The analysis was completed with interviews with key informants. We show that most indicators of the Brazilian FSC standard leave no scope for interpretation. However, companies are certified and re-certified with a significant number of minor non-conformance with social, legal and environmental indicators. We conclude that some indicators are too broad and need to be clarified. Also, conformity with some indicators depends on actions from governments. The development of new national standards is an opportunity to limit the risks of interpretation of indicators. The updating of standards is also an opportunity to clarify the role of public policies in respect of specific indicators. States wishing to promote FSC certification could seize this opportunity to identify what improvements are needed in the functioning of their institutions and public policies

Induced Variational Method from Supersymmetric Quantum Mechanics and the Screened Coulomb Potential

The formalism of Supersymmetric Quantum Mechanics supplies a trial wave function to be used in the Variational Method. The screened Coulomb potential is analysed within this approach. Numerical and exact results for energy eigenvalues are compared.Comment: 7 pages, LATE

Community based forest management plans in the Brazilian Amazon: current barriers threatening long term economic viability

Community-based forest management (CBFM) projects are often seen as an alternative to protect forest and at the same time to provide incomes for small landholders. Since the mid- 1990s, the number of CBFM projects has increased in the Brazilian Amazon although most of them face several difficulties despite significant public support. Four CBFM plans were analyzed between 2005 and 2010 to assess the evolution of the socioeconomic arrangements and the main barriers threatening their long term viability. The CBFM plans are located in the State of Acre (West Amazon) and in the State of Para (Eastern Amazon). The community forest producers studied live in settlements. The tenure rights model over land and forests varies from one type of settlement to another. New federal regulation issued in 2010 has added more bureaucratic steps to communities applying for rights to explore their portions of forests. The first important barrier to successfully implementation of CBFM is the complex legal framework: it currently takes at least 2 to 3 years to get a plan approved. Moreover management plan elaboration and implementation process is costly. None of the CBFM plan could have been successfully implemented without external national and international financial supports, as well as technical assistance. Community forest certification has decreased and stagnated in the period analyzed. Finally, in the current Amazonian market context, timber harvest only represents a limited complementary income for small farmers, even if forest covers 80 % of their landholding. Market access is very uncertain and small holders communities do not systematically succeed in selling their timber at remunerative prices. Minimum remunerative public prices should be guaranteed for timber from such CBFM plans to make them a truly economic alternative for the Amazon smallholders. (Résumé d'auteur