TY  - GEN
A1  - Ellis, S. C.
A1  - Bauer, S.
A1  - Bacigalupo, C.
A1  - Bland-Hawthorn, J.
A1  - Bryant, J. J.
A1  - Case, S.
A1  - Content, R.
A1  - Fechner, T.
A1  - Giannone, D.
A1  - Haynes, R.
A1  - Hernandez, E.
A1  - Horton, A. J.
A1  - Klauser, U.
A1  - Lawrence, J. S.
A1  - Leon-Saval, S. G.
A1  - Lindley, E.
A1  - Löhmannsröben, Hans-Gerd
A1  - Min, S. -S.
A1  - Pai, N.
A1  - Roth, M.
A1  - Shortridge, K.
A1  - Waller, L.
A1  - Xavier, Pascal
A1  - Zhelem, Ross
T1  - PRAXIS: an OH suppression optimised near infrared spectrograph
T2  - Ground-based and Airborne Instrumentation for Astronomy VII
N2  - The problem of atmospheric emission from OH molecules is a long standing problem for near-infrared astronomy. PRAXIS is a unique spectrograph which is fed by fibres that remove the OH background and is optimised specifically to benefit from OH-Suppression. The OH suppression is achieved with fibre Bragg gratings, which were tested successfully on the GNOSIS instrument. PRAXIS uses the same fibre Bragg gratings as GNOSIS in its first implementation, and will exploit new, cheaper and more efficient, multicore fibre Bragg gratings in the second implementation. The OH lines are suppressed by a factor of similar to 1000, and the expected increase in the signal-to-noise in the interline regions compared to GNOSIS is a factor of similar to 9 with the GNOSIS gratings and a factor of similar to 17 with the new gratings. PRAXIS will enable the full exploitation of OH suppression for the first time, which was not achieved by GNOSIS (a retrofit to an existing instrument that was not OH-Suppression optimised) due to high thermal emission, low spectrograph transmission and detector noise. PRAXIS has extremely low thermal emission, through the cooling of all significantly emitting parts, including the fore-optics, the fibre Bragg gratings, a long length of fibre, and the fibre slit, and an optical design that minimises leaks of thermal emission from outside the spectrograph. PRAXIS has low detector noise through the use of a Hawaii-2RG detector, and a high throughput through a efficient VPH based spectrograph. PRAXIS will determine the absolute level of the interline continuum and enable observations of individual objects via an IFU. In this paper we give a status update and report on acceptance tests.
KW  - Near infrared
KW  - spectroscopy
KW  - OH suppression
KW  - astrophotonics
KW  - fibre Bragg gratings
Y1  - 2018
SN  - 978-1-5106-1958-6
U6  - https://doi.org/10.1117/12.2311898
SN  - 0277-786X
SN  - 1996-756X
VL  - 10702
PB  - SPIE-INT Soc Optical Engineering
CY  - Bellingham
ER  - 
TY  - JOUR
A1  - De Frenne, Pieter
A1  - Rodriguez-Sanchez, Francisco
A1  - Coomes, David Anthony
A1  - Bäten, Lander
A1  - Versträten, Gorik
A1  - Vellend, Mark
A1  - Bernhardt-Römermann, Markus
A1  - Brown, Carissa D.
A1  - Brunet, Jörg
A1  - Cornelis, Johnny
A1  - Decocq, Guillaume M.
A1  - Dierschke, Hartmut
A1  - Eriksson, Ove
A1  - Gilliam, Frank S.
A1  - Hedl, Radim
A1  - Heinken, Thilo
A1  - Hermy, Martin
A1  - Hommel, Patrick
A1  - Jenkins, Michael A.
A1  - Kelly, Daniel L.
A1  - Kirby, Keith J.
A1  - Mitchell, Fraser J. G.
A1  - Naaf, Tobias
A1  - Newman, Miles
A1  - Peterken, George
A1  - Petrik, Petr
A1  - Schultz, Jan
A1  - Sonnier, Gregory
A1  - Van Calster, Hans
A1  - Waller, Donald M.
A1  - Walther, Gian-Reto
A1  - White, Peter S.
A1  - Woods, Kerry D.
A1  - Wulf, Monika
A1  - Graae, Bente Jessen
A1  - Verheyen, Kris
T1  - Microclimate moderates plant responses to macroclimate warming
JF  - Proceedings of the National Academy of Sciences of the United States of America
N2  - Recent global warming is acting across marine, freshwater, and terrestrial ecosystems to favor species adapted to warmer conditions and/or reduce the abundance of cold-adapted organisms (i.e., "thermophilization" of communities). Lack of community responses to increased temperature, however, has also been reported for several taxa and regions, suggesting that "climatic lags" may be frequent. Here we show that microclimatic effects brought about by forest canopy closure can buffer biotic responses to macroclimate warming, thus explaining an apparent climatic lag. Using data from 1,409 vegetation plots in European and North American temperate forests, each surveyed at least twice over an interval of 12-67 y, we document significant thermophilization of ground-layer plant communities. These changes reflect concurrent declines in species adapted to cooler conditions and increases in species adapted to warmer conditions. However, thermophilization, particularly the increase of warm-adapted species, is attenuated in forests whose canopies have become denser, probably reflecting cooler growing-season ground temperatures via increased shading. As standing stocks of trees have increased in many temperate forests in recent decades, local microclimatic effects may commonly be moderating the impacts of macroclimate warming on forest understories. Conversely, increases in harvesting woody biomass-e.g., for bioenergy-may open forest canopies and accelerate thermophilization of temperate forest biodiversity.
KW  - climate change
KW  - forest management
KW  - understory
KW  - climatic debt
KW  - range shifts
Y1  - 2013
U6  - https://doi.org/10.1073/pnas.1311190110
SN  - 0027-8424
VL  - 110
IS  - 46
SP  - 18561
EP  - 18565
PB  - National Acad. of Sciences
CY  - Washington
ER  -