524 research outputs found
Data Paper – High Resolution Vegetation Cover Data for the Southern Western Ghats of India. (IFP_ECODATA_VEGETATION)
This data paper has been prepared following the Ecological Metadata format proposed by Michener et al. (1997). It is accompanied with data archives downloadable from the IFP Biodiversity Portal at http://www.ifpindia.org/biodiversityportal/The Western Ghats form a 1,600 km long escarpment that runs parallel to the southwestern coast of Peninsular India. This relief barrier, which orographically exacerbates the summer monsoon rains, is responsible for steep bioclimatic gradients that have long been recognized as one of the major ecological determinants for the forest vegetation of the region. We report here girded vegetation data at 30' lat/long (ca. 1 km) resolution that cover an area of about 70,000 km2 of the southern Western Ghats, between 74 to 78° E and 8 to 16° N. These data have been extracted from: the 1:250,000 scale forest maps of South India published by the French Institute of Pondicherry (FIP), which have been digitized and simplified; the 2004 MODIS (Moderate Resolution Imaging Spectroradiometer) database, for the IGBP (International Biosphere Geosphere Programme) global vegetation Land Cover Type and Normalized Difference Vegetation Index (NDVI) of March 2004
Flying phase mask for the printing of long submicron-period stitchingless gratings
International audienceLong and stitchingless gratings are printed by means of a read/write head comprising a phase mask illuminated by an intensity modulated laser beam and a reference grating displacement sensor which dictates the modulation period real time. A nearly perfect grating copying is achieved by fixing the sensor grating scale and the written grating substrate on a long platform sliding under the read/write hea
Pattern and process in Amazon tree turnover, 1976-2001
Previous work has shown that tree turnover, tree biomass and large liana densities have increased in mature tropical forest plots in the late twentieth century. These results point to a concerted shift in forest ecological processes that may already be having significant impacts on terrestrial carbon stocks, fluxes and biodiversity. However, the findings have proved controversial, partly because a rather limited number of permanent plots have been monitored for rather short periods. The aim of this paper is to characterize regional-scale patterns of 'tree turnover' (the rate with which trees die and recruit into a population) by using improved datasets now available for Amazonia that span the past 25 years. Specifically, we assess whether concerted changes in turnover are occurring, and if so whether they are general throughout the Amazon or restricted to one region or environmental zone. In addition, we ask whether they are driven by changes in recruitment, mortality or both. We find that: (i) trees 10 cm or more in diameter recruit and die twice as fast on the richer soils of southern and western Amazonia than on the poorer soils of eastern and central Amazonia; (ii) turnover rates have increased throughout Amazonia over the past two decades; (iii) mortality and recruitment rates have both increased significantly in every region and environmental zone, with the exception of mortality in eastern Amazonia; (iv) recruitment rates have consistently exceeded mortality rates; (v) absolute increases in recruitment and mortality rates are greatest in western Amazonian sites; and (vi) mortality appears to be lagging recruitment at regional scales. These spatial patterns and temporal trends are not caused by obvious artefacts in the data or the analyses. The trends cannot be directly driven by a mortality driver (such as increased drought or fragmentation-related death) because the biomass in these forests has simultaneously increased. Our findings therefore indicate that long-acting and widespread environmental changes are stimulating the growth and productivity of Amazon forests
Design and construction of a Cherenkov imager for charge measurement of nuclear cosmic rays
A proximity focusing Cherenkov imager called CHERCAM, has been built for the
charge measurement of nuclear cosmic rays with the CREAM instrument. It
consists of a silica aerogel radiator plane across from a detector plane
equipped with 1,600 1" diameter photomultipliers. The two planes are separated
by a ring expansion gap. The Cherenkov light yield is proportional to the
charge squared of the incident particle. The expected relative light collection
accuracy is in the few percents range. It leads to an expected single element
separation over the range of nuclear charge Z of main interest 1 < Z < 26.
CHERCAM is designed to fly with the CREAM balloon experiment. The design of the
instrument and the implemented technical solutions allowing its safe operation
in high altitude conditions (radiations, low pressure, cold) are presented.Comment: 24 pages, 19 figure
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Impact of particles on the Planck HFI detectors: Ground-based measurements and physical interpretation
The Planck High Frequency Instrument (HFI) surveyed the sky continuously from
August 2009 to January 2012. Its noise and sensitivity performance were
excellent, but the rate of cosmic ray impacts on the HFI detectors was
unexpectedly high. Furthermore, collisions of cosmic rays with the focal plane
produced transient signals in the data (glitches) with a wide range of
characteristics. A study of cosmic ray impacts on the HFI detector modules has
been undertaken to categorize and characterize the glitches, to correct the HFI
time-ordered data, and understand the residual effects on Planck maps and data
products. This paper presents an evaluation of the physical origins of glitches
observed by the HFI detectors. In order to better understand the glitches
observed by HFI in flight, several ground-based experiments were conducted with
flight-spare HFI bolometer modules. The experiments were conducted between 2010
and 2013 with HFI test bolometers in different configurations using varying
particles and impact energies. The bolometer modules were exposed to 23 MeV
protons from the Orsay IPN TANDEM accelerator, and to Am and Cm
-particle and Fe radioactive X-ray sources. The calibration data
from the HFI ground-based preflight tests were used to further characterize the
glitches and compare glitch rates with statistical expectations under
laboratory conditions. Test results provide strong evidence that the dominant
family of glitches observed in flight are due to cosmic ray absorption by the
silicon die substrate on which the HFI detectors reside. Glitch energy is
propagated to the thermistor by ballistic phonons, while there is also a
thermal diffusion contribution. The implications of these results for future
satellite missions, especially those in the far-infrared to sub-millimetre and
millimetre regions of the electromagnetic spectrum, are discussed.Comment: 11 pages, 13 figure
Should we welcome robot teachers?
Abstract Current uses of robots in classrooms are
reviewed and used to characterise four scenarios: (s1)
Robot as Classroom Teacher; (s2) Robot as Companion
and Peer; (s3) Robot as Care-eliciting Companion; and (s4)
Telepresence Robot Teacher. The main ethical concerns
associated with robot teachers are identified as: privacy;
attachment, deception, and loss of human contact; and
control and accountability. These are discussed in terms of
the four identified scenarios. It is argued that classroom
robots are likely to impact children’s’ privacy, especially
when they masquerade as their friends and companions,
when sensors are used to measure children’s responses, and
when records are kept. Social robots designed to appear as
if they understand and care for humans necessarily involve
some deception (itself a complex notion), and could
increase the risk of reduced human contact. Children could
form attachments to robot companions (s2 and s3), or robot
teachers (s1) and this could have a deleterious effect on
their social development. There are also concerns about the
ability, and use of robots to control or make decisions
about children’s behaviour in the classroom. It is concluded
that there are good reasons not to welcome fully fledged
robot teachers (s1), and that robot companions (s2 and 3)
should be given a cautious welcome at best. The limited
circumstances in which robots could be used in the classroom
to improve the human condition by offering otherwise
unavailable educational experiences are discussed
Recurrence of Dupuytren’s contracture: A consensus-based definition
Purpose: One of the major determinants of Dupyutren disease (DD) treatment efficacy is recurrence of the contracture. Unfortunately, lack of agreement in the literature on what constitutes recurrence makes it nearly impossible to compare the multiple treatments alternatives available today. The aim of this study is to bring an unbiased pool of experts to agree upon what would be considered a recurrence of DD after treatment; and from that consensus establish a much-needed definition for DD recurrence. Methods: To reach an expert consensus on the definition of recurrence we used the Delphi method and invited 43 Dupuytren’s research and treatment experts from 10 countries to participate by answering a series of questionnaire rounds. After each round the answers were analyzed and the experts received a feedback report with another questionnaire round to further hone in of the definition. We defined consensus when at least 70% of the experts agreed on a topic. Results: Twenty-one experts agreed to participate in this study. After four consensus rounds, we agreed that DD recurrence should be defined as “more than 20 degrees of contracture recurrence in any treated joint at one year post-treatment compared to six weeks post-treatment”. In addition, “recurrence should be reported individually for every treated joint” and afterwards measurements should be repeated and reported yearly. Conclusion: This study provides the most comprehensive to date definition of what should be considered recurrence of DD. These standardized criteria should allow us to better evaluate the many treatment alternatives
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