940 research outputs found
A satisfação no trabalho: Teorias processuais: Uma revisão de aspectos teoricos e práticos
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Reflecting on the next generation of models for community-based natural resources management
Community-based natural resource management (CBNRM) has been a pervasive paradigm in conservation circles for three decades. Despite many potentially attractive attributes it has been extensively critiqued from both ecological and sociological perspectives with respect to theory and practice (for example Leach et al. 1999; Berkes 2004; Fabricius et al. 2004; Blaikie 2006). Nonetheless, many successful examples exist, although an equal number have seemingly not met expectations. Is this because of poor implementation or rather a generally flawed model? If the criteria and conditions for success are so onerous that relatively few projects or situations are likely to qualify, what then is the value of the model? The questions thus become: how and what can we learn from the past theory and practice to develop a new generation of flexible, locally responsive and implementable CBNRM models, and what are likely to be the attributes of such models
The relative representation of ecosystem services and disservices in South African newspaper media
Newspapers are key information sources and may influence both public opinion and policy. Previous studies have analysed the portrayal of ecosystem disservices in newspapers, but none have assessed the relative coverage between disservices and services, or how it might have changed over time. We report on the relative frequency and depiction of ecosystem services and disservices in South African, English newspapers over a 15-year period. We used a SABINET search complemented by key-informant interviews with environmental journalists. For each article we recorded if it covered ecosystem services or disservices, the type of service or disservice, and article tone and length. Overall, 2,201 articles were found, of which 25% were on services and 75% on disservices. The number of articles per year declined over the 15-year period for services, but not disservices. The most common services were energy and craft materials, food production, recreation and culture, and disservices were human health, heat waves and floods. Articles on ecosystem services were 25–40% longer than those on disservices. Article lengths on both declined over the 15 years. The greater reporting of ecosystem disservices over services is likely to influence public opinion and environmental decision-making accordingly
History of Plio-Pleistocene Climate in the Northeastern Atlantic, Deep Sea Drilling Project Hole 552A
DSDP Hole 552A, cored with the HPC on Hatton Drift, represents an almost complete and undisturbed sediment section spanning the late Neogene and Quaternary. Lithologic, faunal, isotopic, and paleomagnetic analyses indicate that the section represents the most complete deep sea record of climatic evolution hitherto recovered at high latitudes in the northern hemisphere. A glacial record of remarkable resolution for the late Pliocene and Pleistocene is provided by oxygen and carbon isotope ratios in benthic foraminifers. In the upper part of the section, the whole of the standard oxygen isotope record of the past million years is well preserved. The onset of ice-rafting and glacial-interglacial alternations occurs at about 2.4 m.y. ago
Handwriting-Based Gender Classification Using End-to-End Deep Neural Networks
Handwriting-based gender classification is a well-researched problem that has
been approached mainly by traditional machine learning techniques. In this
paper, we propose a novel deep learning-based approach for this task.
Specifically, we present a convolutional neural network (CNN), which performs
automatic feature extraction from a given handwritten image, followed by
classification of the writer's gender. Also, we introduce a new dataset of
labeled handwritten samples, in Hebrew and English, of 405 participants.
Comparing the gender classification accuracy on this dataset against human
examiners, our results show that the proposed deep learning-based approach is
substantially more accurate than that of humans
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Late Neogene chronology: New perspectives in high-resolution stratigraphy
We present an integrated geochronology for late Neogene time (Pliocene, Pleistocene, and Holocene Epochs) based on an analysis of data from stable isotopes, magnetostratigraphy, radiochronology, and calcareous plankton biostratigraphy. Discrepancies between recently formulated astronomical chronologies and magnetochronologies for the past 6 m.y. have been resolved on the basis of new, high-precision Ar/Ar ages in the younger part of this interval, the so-called Brunhes, Matuyama, and Gauss Epochs (= Chrons C1n-C2An; 0-3.58 Ma), and revised analysis of sea floor anomalies in the Pacific Ocean in the older part, the so-called Gilbert Epoch (= Chron C2Ar-C3r; 3.58-5.89 Ma). The magneto- and astrochronologies are now concordant back to the Chron C3r/C3An boundary at 5.89 Ma. The Neogene (Miocene, Pliocene, Pleistocene, and Holocene) and Paleogene are treated here as period/system subdivisions of the Cenozoic Era/Erathem, replacements for the antiquated terms Tertiary and Quaternary. The boundary between the Miocene and Pliocene Series (Messinian/Zanclean Stages), whose global stratotype section and point (GSSP) is currently proposed to be in Sicily, is located within the reversed interval just below the Thvera (C3n.4n) Magnetic Polarity Subchronozone with an estimated age of 5.32 Ma. The Pliocene/Pleistocene boundary, whose GSSP is located at Vrica (Calabria, Italy), is located near the top of the Olduvai (C2n) Magnetic Polarity Subchronozone with an estimated age of 1.81 Ma. The 13 calcareous nannoplankton and 48 planktonic foraminiferal datum events for the Pliocene, and 12 calcareous nannoplankton and 10 planktonic foraminiferal datum events for the Pleistocene, are calibrated to the newly revised late Neogene astronomical/geomagnetic polarity time scale
Ergogenic effects of spinal cord stimulation on exercise performance following spinal cord injury
Cervical or upper-thoracic spinal cord injury (SCI, ≥T6) often leads to low resting blood pressure (BP) and impaired cardiovascular responses to acute exercise due to disrupted supraspinal sympathetic drive. Epidural spinal cord stimulation (invasive, ESCS) and transcutaneous spinal cord stimulation (non-invasive, TSCS) have previously been used to target dormant sympathetic circuits and modulate cardiovascular responses. This case series compared the effects of cardiovascular-optimised ESCS and TSCS versus sham ESCS and TSCS on modulating cardiovascular responses and improving submaximal upper-body exercise performance in individuals with SCI. Seven males with a chronic, motor-complete SCI between C6 and T4 underwent a mapping session to identify cardiovascular responses to spinal cord stimulation. Subsequently, four participants (two ESCS and two TSCS) completed submaximal exercise testing. Stimulation parameters (waveform, frequency, intensity, epidural electrode array configuration, and transcutaneous electrode locations in the lumbosacral region) were optimised to elevate cardiovascular responses (CV-SCS). A sham condition (SHAM-SCS) served as a comparison. Participants performed arm-crank exercise to exhaustion at a fixed workload corresponding to above ventilatory threshold, on separate days, with CV-SCS or SHAM-SCS. At rest, CV-SCS increased BP and predicted left ventricular cardiac contractility and total peripheral resistance. During exercise, CV-SCS increased time to exhaustion and peak oxygen pulse (a surrogate for stroke volume), relative to SHAM-SCS. Ratings of perceived exertion also tended to be lower with CV-SCS than SHAM-SCS. Comparable improvements in time to exhaustion with ESCS and TSCS suggest that both approaches could be promising ergogenic aids to support exercise performance or rehabilitation, along with reducing fatigue during activities of daily living in individuals with SCI
Textural variations in Neogene pelagic carbonate ooze at DSDP Site 593, southern Tasman Sea, and their paleoceanographic implications
Changes in Neogene sediment texture in pelagic carbonate-rich oozes on the Challenger Plateau, southern Tasman Sea, are used to infer changes in depositional paleocurrent velocities. The most obvious record of textural change is in the mud:sand ratio. Increases in the sand content are inferred to indicate a general up-core trend towards increasing winnowing of sediments resulting from increasing flow velocity of Southern Component Intermediate Water (SCIW), the forerunner of Antarctic Intermediate Water. In particular, the intervals c. 19-14.5 Ma, c. 9.5-8 Ma, and after 5 Ma are suggested to be times of increased SCIW velocity and strong sediment winnowing. Within the mud fraction, the fine silt to coarse clay sizes from 15.6 to 2 µm make the greatest contribution to the sediments and are composed of nannofossil plates. During extreme winnowing events it is the fine silt to very coarse clay material (13-3 µm) within this range that is preferentially removed, suggesting the 10 µm cohesive silt boundary reported for siliciclastic sediments does not apply to calcitic skeletal grains. The winnowed sediment comprises coccolithophore placoliths and spheres, represented by a mode at 4-7 µm.
Further support for seafloor winnowing is gained from the presence in Hole 593 of a condensed sedimentary section from c. 18 to 14 Ma where the sand content increases to c. 20% of the bulk sample. Associated with the condensed section is a 6 m thick orange unit representing sediments subjected to particularly oxygen-rich, late early to early middle Miocene SCIW. Together these are inferred to indicate increased SCIW velocity resulting in winnowed sediment associated with faster arrival of oxygen-rich surface water subducted to form SCIW. Glacial development of Antarctica has been recorded from many deep-sea sites, with extreme glacials providing the mechanism to increase watermass flow. Miocene glacial zones Mi1b-Mi6 are identified in an associated oxygen isotope record from Hole 593, and correspond with times of particularly invigorated paleocirculation, bottom winnowing, and sediment textural changes
Modeling the dynamics of glacial cycles
This article is concerned with the dynamics of glacial cycles observed in the geological record of the Pleistocene Epoch. It focuses on a conceptual model proposed by Maasch and Saltzman [J. Geophys. Res.,95, D2 (1990), pp. 1955-1963], which is based on physical arguments and emphasizes the role of atmospheric CO2 in the generation and persistence of periodic orbits (limit cycles). The model consists of three ordinary differential equations with four parameters for the anomalies of the total global ice mass, the atmospheric CO2 concentration, and the volume of the North Atlantic Deep Water (NADW). In this article, it is shown that a simplified two-dimensional symmetric version displays many of the essential features of the full model, including equilibrium states, limit cycles, their basic bifurcations, and a Bogdanov-Takens point that serves as an organizing center for the local and global dynamics. Also, symmetry breaking splits the Bogdanov-Takens point into two, with different local dynamics in their neighborhoods
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