22 research outputs found
Unusual Emissions at Various Energies Prior to the Impulsive Phase of the Large Solar Flare and Coronal Mass Ejection of 4 November 2003
The GOES X28 flare of 4 November 2003 was the largest ever recorded in its class. It produced the first evidence for two spectrally separated emission components, one at microwaves and the other in the THz range of frequencies.We analyzed the pre-flare phase of this large flare, twenty minutes before the onset of the major impulsive burst. This periodis characterized by unusual activity in X-rays, sub-THz frequencies, H, and microwaves.The CME onset occurred before the onset of the large burst by about 6 min
Sub-THz and H{\alpha} activity during the preflare and main phases of a GOES class M2 event
Radio and optical observations of the evolution of flare-associated phenomena
have shown an initial and rapid burst at 0.4 THz only followed subsequently by
a localized chromospheric heating producing an H{\alpha} brightening with later
heating of the whole active region. A major instability occurred several
minutes later producing one impulsive burst at microwaves only, associated with
an M2.0 GOES X-ray flare that exhibited the main H{\alpha} brightening at the
same site as the first flash. The possible association between long-enduring
time profiles at soft X-rays, microwaves, H{\alpha} and sub-THz wavelengths is
discussed. In the decay phase the H{\alpha} movie shows a disrupting magnetic
arch structure ejecting dark, presumably chromospheric, material upwards. The
time sequence of events suggests genuine interdependent and possibly
non-thermal instabilities triggering phenomena, with concurrent active region
plasma heating and material ejection.Comment: Accepted by Astrophysical Journal, October 13, 201
Rapid tree carbon stock recovery in managed Amazonian forests.
While around 20% of the Amazonian forest has been cleared for pastures and agriculture, one fourth of the remaining forest is dedicated to wood production [1] . Most of these production forests have been or will be selectively harvested for commercial timber, but recent studies show that even soon after logging, harvested stands retain much of their tree-biomass carbon and biodiversity [2,3] . Comparing species richness of various animal taxa among logged and unlogged forests across the tropics, Burivalova et al.[4] found that despite some variability among taxa, biodiversity loss was generally explained by logging intensity (the number of trees extracted). Here, we use a network of 79 permanent sample plots (376 ha total) located at 10 sites across the Amazon Basin [5] to assess the main drivers of time-to-recovery of post-logging tree carbon ( Table S1 ). Recovery time is of direct relevance to policies governing management practices (i.e., allowable volumes cut and cutting cycle lengths), and indirectly to forest-based climate change mitigation interventions
The tropical managed forests observatory: a research network addressing the future of tropical logged forests.
While attention on logging in the tropics has been increasing, studies on the long-term effects of silviculture on forest dynamics and ecology remain scare and spatially limited. Indeed, most of our knowledge on tropical forests arises from studies carried out in undisturbed tropical forests. This biasis problematic given that logged and disturbed tropical forests are now covering a larger area thantheso-alled primary forests. A new network of permanent sample plots in logged forests, the Tropical managed Forests Observatory (TmFO), aims to ?ll this gap by providing unprecedented opportunities to examine long-term data on the resilience of logged tropical forests at regional and global scales. TmFO currently includes 24 experimental sites distributed across three tropical regions, with a total of 490 permanent plots and 921 ha of forest inventories
The historical roots of multicultural unity along the Upper Guinea Coast and in Guinea-Bissau
Optimal strategies of Ecosystem Services provision for Amazonian production forests.
Although tropical forests harbour most of the terrestrial carbon and biological diversity on Earth they continue to be deforested or degraded at high rates. In Amazonia, the largest tropical forest on Earth, a sixth of the remaining natural forests is formally dedicated to timber extraction through selective logging. Reconciling timber extraction with the provision of other ecosystem services (ES) remains a major challenge for forest managers and policy makers. This study applies a spatial optimisation of logging in Amazonian production forests to analyse potential trade-offs between timber extraction and recovery, carbon storage, and biodiversity conservation. Current logging regulations with unique cutting cycles result in sub-optimal ES-use efficiency. Long-term timber provision would require the adoption of a land-sharing strategy that involves extensive low-intensity logging, although high transport and road-building costs might make this approach economically unattractive. By contrast, retention of carbon and biodiversity would be enhanced by a land-sparing strategy restricting high-intensive logging to designated areas such as the outer fringes of the region. Depending on management goals and societal demands, either choice will substantially in uence the future of Amazonian forests. Overall, our results highlight the need for reevaluation of current logging regulations and regional cooperation among Amazonian countries to enhance coherent and trans-boundary forest management.Made available in DSpace on 2020-01-14T18:10:56Z (GMT). No. of bitstreams: 1
CPAFAP2019Optimalstrategiesofecosystemservices.pdf: 775227 bytes, checksum: 2c82d5c6280350cecac9770db875ae0a (MD5)
Previous issue date: 2019bitstream/item/206608/1/CPAF-AP-2019-Optimal-strategies-of-ecosystem-services.pdfNa publicação consta: Lucas Mazzei
Rapid tree carbon stock recovery in managed Amazonian forests.
While around 20% of the Amazonian forest has been cleared for pastures and agriculture, one fourth of the remaining forest is dedicated to wood production [1] . Most of these production forests have been or will be selectively harvested for commercial timber, but recent studies show that even soon after logging, harvested stands retain much of their tree-biomass carbon and biodiversity [2,3] . Comparing species richness of various animal taxa among logged and unlogged forests across the tropics, Burivalova et al.[4] found that despite some variability among taxa, biodiversity loss was generally explained by logging intensity (the number of trees extracted). Here, we use a network of 79 permanent sample plots (376 ha total) located at 10 sites across the Amazon Basin [5] to assess the main drivers of time-to-recovery of post-logging tree carbon ( Table S1 ). Recovery time is of direct relevance to policies governing management practices (i.e., allowable volumes cut and cutting cycle lengths), and indirectly to forest-based climate change mitigation interventions.201
The Tropical managed Forests Observatory: a research network addressing the future of tropical logged forests
Reverse Logistics: Overview and Challenges for Supply Chain Management
This paper is aimed at introducing the concept of reverse logistics (RL) and its implications for supply chain management (SCM). RL is a research area focused on the management of the recovery of products once they are no longer desired (end-of-use products, EoU) or can no longer be used (end-of-life products) by the consumers, in order to obtain an economic value from the recovered products. This way, RL has become a matter of strategic importance, an element that companies are considering in their decision-making processes related to the design and development of their supply chains. In addition, a description of the implications of RL for SCM will be discussed and, finally, an analysis of some of the opportunities and challenges that RL implies for SCM will be presented