Neighborhood and community interactions determine the spatial pattern of tropical tree seedling survival

Factors affecting survival and recruitment of 3531 individually mapped seedlings of Myristicaceae were examined over three years in a highly diverse neotropical rain forest, at spatial scales of 1–9 m and 25 ha. We found convincing evidence of a community compensatory trend (CCT) in seedling survival (i.e., more abundant species had higher seedling mortality at the 25-ha scale), which suggests that density-dependent mortality may contribute to the spatial dynamics of seedling recruitment. Unlike previous studies, we demonstrate that the CCT was not caused by differences in microhabitat preferences or life history strategy among the study species. In local neighborhood analyses, the spatial autocorrelation of seedling survival was important at small spatial scales (1–5 m) but decayed rapidly with increasing distance. Relative seedling height had the greatest effect on seedling survival. Conspecific seedling density had a more negative effect on survival than heterospecific seedling density and was stronger and extended farther in rare species than in common species. Taken together, the CCT and neighborhood analyses suggest that seedling mortality is coupled more strongly to the landscape-scale abundance of conspecific large trees in common species and the local density of conspecific seedlings in rare species. We conclude that negative density dependence could promote species coexistence in this rain forest community but that the scale dependence of interactions differs between rare and common species

Physiological Performance in Full-Sun Vs. Shaded Post-Fire Malosma laurina Seedlings

Post-fire Malosma laurina regenerates both by resprouting and by disseminating seeds. The objective of this study is to assess seedling performance either in full-sunlight or in artificially shaded treatments. By identifying under which conditions Malosma laurina seedlings grow more effectively, one can predict where post-fire M. laurina seedling communities will thrive. The methodology employed throughout this experiment began by covering existing seedlings with shade cloth held by wooden stakes. These treatments were adjacent to full-sun environments; each of which contained at least two Malosma laurina seedlings. Six experimental sites were set up, and the seedlings in question were monitored for growth, conductance, relative humidity, temperature, and light exposure. Water potential was also measured once at each site at the conclusion of the experiment. The results show that seedlings under a shady protection grow taller and transpire less water on average than seedlings that are exposed to full sunlight. The shaded seedlings looked healthier than their full-sun counterparts. It can be concluded that seedlings have better physiological success under shade protection than under full sun

Space-Based Telemetry And Range Safety Flight Demonstration #1

The basic ability of STARS to maintain a satellite communications link with TDRSS satellites during dynamic aircraft flights was successfully demonstrated during FD 1. The Range Safety and Range User systems' link margins were measured. The ability to acquire/reacquire and maintain lock between a high-dynamic vehicle and a satellite-based system was demonstrated. The Range Safety system simultaneously received and processed command links from space and ground transmitters and provided near real-time Range Safety telemetry to DFRC, which then sent it in near real time to KSC, GSFC, and WFF for monitoring. The GPS receiver maintained track except during extremely dynamic maneuvers. The Range User system sent data at three different data rates. There were excellent cooperation and support from the different Centers, contractors, and Ranges. A large amount of data was recorded and extensive post-flight analysis was performed. The Range User TDRSS link margin met or exceeded the predicted performance at three different data rates. The Range Safety launch-head link margins generally agreed with the predicted performance. The UPS positions and velocities agreed with those from tracking radar to within about 20 m and a few rn/s. The link margins for the Range Safety TDRSS telemetry link were less than expected. The link margin for one TDRSS command link LPT channel was occasionally much less than the other. Additional post-flight testing has yet to identify the root causes of these results. There were many lessons learned from this first set of test flights. The most important one is that more time and testing are needed for each step to deal with the inevitable problems. It is vital that these lessons be among the primary areas of study that will carry over from FD#1 to FD#2, which is currently scheduled for early FY05 at DFRC and will use a specially designed Ku-band phased array antenna for the Range User system. The next series of flight demonstrations scheduled for late 2004 at DFRC will incorporate many lessons learned from FD#1. A specially designed Ku-band phased array antenna will be used with the Range User system. A test flight on a hypersonic vehicle is planned by the end of 2006

Arc-continent collision and orocline formation: Closing of the Central American seaway

Closure of the Central American seaway was a local tectonic event with potentially global biotic and environmental repercussions. We report geochronological (six U/Pb LA-ICP-MS zircon ages) and geochemical (19 XRF and ICP-MS analyses) data from the Isthmus of Panama that allow definition of a distinctive succession of plateau sequences to subduction-related protoarc to arc volcaniclastic rocks intruded by Late Cretaceous to middle Eocene intermediate plutonic rocks (67.6 ± 1.4 Ma to 41.1 ± 0.7 Ma). Paleomagnetic analyses (24 sites, 192 cores) in this same belt reveal large counterclockwise vertical-axis rotations (70.9° ± 6.7°), and moderate clockwise rotations (between 40° ± 4.1° and 56.2° ± 11.1°) on either side of an east-west trending fault at the apex of the Isthmus (Rio Gatun Fault), consistent with Isthmus curvature. An Oligocene-Miocene arc crosscuts the older, deformed and segmented arc sequences, and shows no significant vertical-axis rotation or deformation. There are three main stages of deformation: 1) left-lateral, strike-slip offset of the arc (∼100 km), and counterclockwise vertical-axis rotation of western arc segments between 38 and 28 Ma; 2) clockwise rotation of central arc segments between 28 and 25 Ma; and 3) orocline tightening after 25 Ma. When this reconstruction is placed in a global plate tectonic framework, and published exhumation data is added, the Central American seaway disappears at 15 Ma, suggesting that by the time of northern hemisphere glaciation, deep-water circulation had long been severed in Central America

Barreras psicosociales para la vinculación laboral de excombatientes

In the framework of the signing of the peace agreement between FARC-EP and the Colombian government, the concern arises about how the processes of labor inclusion of demobilized combatants are taking place and what role psychosocial barriers for peace play. Thus, a documentary review was made of the main findings that some researchers have had regarding the reintegration processes of the demobilized population within the labor world and the psychosocial barriers that have been built in Colombia so that these processes can be fully developed. The findings show that the labor sector, being immersed in the social constructions and discourses on demobilized people, has also established stigmatization and rejection processes within its hiring processes, which strongly evidence the presence of psychosocial barriers to reintegration, reconciliation and peace within the organizations.En el marco de la firma del acuerdo de paz entre las FARC-EP y el gobierno colombiano, surge la inquietud de cómo se están dando los procesos de inclusión laboral de los desmovilizados y qué papel juegan las Barreras psicosociales para la paz, por lo que se hizo una revisión documental de los principales hallazgos que han tenido algunos investigadores con respecto a los procesos de reintegración de la población desmovilizada dentro del mundo laboral y las barreras psicosociales que se han construido en Colombia para que estos procesos puedan desarrollarse plenamente. Los hallazgos evidencian que, el sector laboral al estar inmerso dentro de las construcciones y discursos sociales sobre las personas desmovilizadas, han instaurado también procesos de estigmatización y rechazo dentro de sus procesos de contratación, que permiten evidenciar fuertemente la presencia de barreras psicosociales para la reintegración, la reconciliación y la paz, dentro de las organizaciones

Estimationof the energy saving potentials in foundry industries based on iso 50001

This paper presents the application of tools to develop a procedure to estimate the energy saving potentials in a small foundry company in Colombia, based on the ISO 50001 standard. This work was carried within the framework of a national industrial project, funded by UNIDO, aimed at the small and medium industrial sector companies (SMEs) of Valle del Cauca, to establish the requirements that are needed to implement an energy management system. With the aim of increasing the energy efficiency of the processes, the energy planning process proposed by ISO 50001 is carried out, whose lead to the establishment of concrete and attainable goals, as well as to the proposal of various improvement plans regarding savings and efficient use of energy. As a result, the savings potentials for the different production levels were estimated, which represents a saving of 15984.25 kWh, which corresponds to 8.7% of the total energy consumed in the 10 months analyzed, and a value of 1486 US

Seasonality of reproduction in an ever-wet lowland tropical forest in Amazonian Ecuador

We thank Pablo Alvia, Alvaro Pérez, Zornitza Aguilar, Paola Barriga, Matt Priest, Caroline Whitefoord, and Gorky Villa for assistance in collecting data or identifying species; Elina Gomez for entry of trap data; Hugo Navarrete, Katya Romoleroux and the QCA herbarium staff, and David Lasso and the ECY staff for help with logistics and needed permitting; Rick Condit, Elizabeth Losos, Robin Foster, and Henrik Balslev for initial encouragement to work within the Yasuní Forest Dynamics Plot; Hugo Romero for initially summarizing the YFDP and SSP weather data sets; Pablo Jarrin for setting up the TEAM weather station, and David Lasso and Carlos Padilla for maintaining that equipment and making the data available; and the Ecuadorian Ministerio del Ambiente for permission to work in Yasuní National Park [No 014-2019-IC-PNY-DPAO/AVS, No 012-2018-IC-PNY593-DPAO/AVS, No 008-2017-IC-PNY-DPAO/AVS, No 012-2016-IC-FAU-FLO-DPAO-PNY, No 594-014-2015-FLO-MAE-DPAO-PNY, and earlier permits]. The Forest Dynamics Plot of Yasuní National Park has been made possible through the generous support of the Pontifical Catholic University of Ecuador (PUCE) funds of donaciones del impuesto a la renta, the Government of Ecuador, the US National Science Foundation, the Andrew W. Mellon Foundation, the Smithsonian Tropical Research Institute, and the University of Aarhus of Denmark. The phenology project began while NCG was at the Natural History Museum, London, with funding (2000–2004) from the Department of Botany (NHM), the Andrew W. Mellon Foundation, British Airways, and the Natural Environment Research Council (GR9/04037). It continued with NCG at Southern Illinois University Carbondale (2005–2023). We thank the Center for Tropical Forest Science for transitional funding (2006–2008, 2017–2018) and the National Science Foundation LTREB program for long-term funding (2006–2020; DEB-0614525, DEB-1122634, DEB-1754632, DEB-1754668).Peer reviewedPublisher PD

An integrative approach unveils FOSL1 as an oncogene vulnerability in KRAS-driven lung and pancreatic cancer

KRAS mutated tumours represent a large fraction of human cancers, but the vast majority remains refractory to current clinical therapies. Thus, a deeper understanding of the molecular mechanisms triggered by KRAS oncogene may yield alternative therapeutic strategies. Here we report the identification of a common transcriptional signature across mutant KRAS cancers of distinct tissue origin that includes the transcription factor FOSL1. High FOSL1 expression identifies mutant KRAS lung and pancreatic cancer patients with the worst survival outcome. Furthermore, FOSL1 genetic inhibition is detrimental to both KRAS-driven tumour types. Mechanistically, FOSL1 links the KRAS oncogene to components of the mitotic machinery, a pathway previously postulated to function orthogonally to oncogenic KRAS. FOSL1 targets include AURKA, whose inhibition impairs viability of mutant KRAS cells. Lastly, combination of AURKA and MEK inhibitors induces a deleterious effect on mutant KRAS cells. Our findings unveil KRAS downstream effectors that provide opportunities to treat KRAS-driven cancers

Modeling Kepler transit light curves as false positives: Rejection of blend scenarios for Kepler-9, and validation of Kepler-9d, a super-Earth-size planet in a multiple system

Light curves from the Kepler Mission contain valuable information on the nature of the phenomena producing the transit-like signals. To assist in exploring the possibility that they are due to an astrophysical false positive, we describe a procedure (BLENDER) to model the photometry in terms of a "blend" rather than a planet orbiting a star. A blend may consist of a background or foreground eclipsing binary (or star-planet pair) whose eclipses are attenuated by the light of the candidate and possibly other stars within the photometric aperture. We apply BLENDER to the case of Kepler-9, a target harboring two previously confirmed Saturn-size planets (Kepler-9b and Kepler-9c) showing transit timing variations, and an additional shallower signal with a 1.59-day period suggesting the presence of a super-Earth-size planet. Using BLENDER together with constraints from other follow-up observations we are able to rule out all blends for the two deeper signals, and provide independent validation of their planetary nature. For the shallower signal we rule out a large fraction of the false positives that might mimic the transits. The false alarm rate for remaining blends depends in part (and inversely) on the unknown frequency of small-size planets. Based on several realistic estimates of this frequency we conclude with very high confidence that this small signal is due to a super-Earth-size planet (Kepler-9d) in a multiple system, rather than a false positive. The radius is determined to be 1.64 (+0.19/-0.14) R(Earth), and current spectroscopic observations are as yet insufficient to establish its mass.Comment: 20 pages in emulateapj format, including 8 tables and 16 figures. To appear in ApJ, 1 January 2010. Accepted versio