7,361 research outputs found
Long-Term Vegetation Dynamics in a Megadiverse Hotspot: The Ice-Age Record of a Pre-montane Forest of Central Ecuador.
Tropical ecosystems play a key role in many aspects of Earth system dynamics currently of global concern, including carbon sequestration and biodiversity. To accurately understand complex tropical systems it is necessary to parameterise key ecological aspects, such as rates of change (RoC), species turnover, dynamism, resilience, or stability. To obtain a long-term (>50 years) perspective on these ecological aspects we must turn to the fossil record. However, compared to temperate zones, collecting continuous sedimentary archives in the lowland tropics is often difficult due to the active landscape processes, with potentially frequent volcanic, tectonic, and/or fluvial events confounding sediment deposition, preservation, and recovery. Consequently, the nature, and drivers, of vegetation dynamics during the last glacial are barely known from many non-montane tropical landscapes. One of the first lowland Amazonian locations from which palaeoecological data were obtained was an outcrop near Mera (Ecuador). Mera was discovered, and analysed, by Paul Colinvaux in the 1980s, but his interpretation of the data as indicative of a forested glacial period were criticised based on the ecology and age control. Here we present new palaeoecological data from a lake located less than 10 km away from Mera. Sediment cores raised from Laguna Pindo (1250 masl; 1°27'S, 78°05'W) have been shown to span the late last glacial period [50-13 cal kyr BP (calibrated kiloyears before present)]. The palaeoecological information obtained from Laguna Pindo indicate that the region was characterised by a relatively stable plant community, formed by taxa nowadays common at both mid and high elevations. was the dominant taxon until around 30 cal kyr BP, when it was replaced by , Asteraceae and among other taxa. Heat intolerant taxa including , , and peaked around the onset of the Last Glacial Maximum (c. 21 cal kyr BP). The results obtained from Laguna Pindo support Colinvaux's hypothesis that glacial cooling resulted in a reshuffling of taxa in the region but did not lead to a loss of the forest structure. Wide tolerances of the plant species occurring to glacial temperature range and cloud formation have been suggested to explain Pindo forest stability. This scenario is radically different than the present situation, so vulnerability of the tropical pre-montane forest is highlighted to be increased in the next decades
Extension Programming for Food Entrepreneurs: An Indiana Needs Assessment
The objective of the research reported here was to identify the needs of food entrepreneurs in the state of Indiana. To attain this objective, Purdue Extension educators from 86 counties in Indiana were surveyed. Topics of interest from the survey results included marketing, new business start-up, food regulations, and food safety. This assessment tool has directed Purdue Extension in developing a Food Entrepreneur Engagement Program. The survey results were used to develop a statewide workshop for food entrepreneurs. Resources provided by this program ultimately helped several food entrepreneurs create value-added food businesses in Indiana
Scenarios for Resilient Shrimp Aquaculture in Tropical Coastal Areas
We contend there are currently two competing scenarios for the sustainable development of shrimp aquaculture in coastal areas of Southeast Asia. First, a landscape approach, where farming techniques for small-scale producers are integrated into intertidal areas in a way that the ecological functions of mangroves are maintained and shrimp farming diseases are controlled. Second, a closed system approach, where problems of disease and effluent are eliminated in closed recirculation ponds behind the intertidal zone controlled by industrial-scale producers. We use these scenarios as two ends of a spectrum of possible interactions at a range of scales between the ecological, social, and political dynamics that underlie the threat to the resilience of mangrove forested coastal ecosystems. We discuss how the analytical concepts of resilience, uncertainty, risk, and the organizing heuristic of scale can assist us to understand decision making over shrimp production, and in doing so, explore their use in the empirical research areas of coastal ecology, shrimp health management and epidemiology, livelihoods, and governance in response to the two scenarios. Our conclusion focuses on a series of questions that map out a new interdisciplinary research agenda for sustainable shrimp aquaculture in coastal area
Extremely Inefficient Star Formation in the Outer Disks of Nearby Galaxies
(Abridged) We combine data from The HI Nearby Galaxy Survey and the GALEX
Nearby Galaxy Survey to study the relationship between atomic hydrogen (HI) and
far-ultraviolet (FUV) emission outside the optical radius (r25) in 17 spiral
and 5 dwarf galaxies. In this regime, HI is likely to represent most of the ISM
and FUV emission to trace recent star formation with little bias due to
extinction, so that the two quantities closely trace the underlying
relationship between gas and star formation rate (SFR). The azimuthally
averaged HI and FUV intensities both decline with increasing radius in this
regime, with the scale length of the FUV profile typically half that of the HI
profile. Despite the mismatch in profiles, there is a significant spatial
correlation (at 15" resolution) between local FUV and HI intensities; near r25
this correlation is quite strong, in fact stronger than anywhere inside r25,
and shows a decline towards larger radii. The star formation efficiency (SFE) -
defined as the ratio of FUV/HI and thus the inverse of the gas depletion time -
decreases with galactocentric radius across the outer disks, though much
shallower than across the optical disks. On average, we find the gas depletion
times to be well above a Hubble time (~10^11 yr). We observe a clear
relationship between FUV/HI and HI column in the outer disks, with the SFE
increasing with increasing HI column. Despite observing systematic variations
in FUV/HI, we find no clear evidence for step-function type star formation
thresholds. When compared with results from inside r25, we find outer disk star
formation to be distinct in several ways: it is extremely inefficient
(depletion times of many Hubble times) with column densities and SFRs lower
than found anywhere inside the optical disks. It appears that the HI column is
one of, perhaps even the key environmental factor in setting the SFR in outer
galaxy disks.Comment: Accepted for Publication in The Astronomical Journa
Whitefish Wars: Pangasius, politics and consumer confusion in Europe
Rapid growth in production of the farmed Vietnamese whitefish pangasius and its trade with the European Union has provoked criticism of the fish’s environmental, social and safety credentials by actors including WWF and Members of the European Parliament and associated negative media coverage. This paper reviews the range of claims communicated about pangasius (identified as a form of mass mediated risk governance), in light of scientific evidence and analysis of data from the EU’s Rapid Alert System for Food and Feeds food safety notification system for imported seafood. This analysis shows pangasius is to be generally safe, environmentally benign, and beneficial for actors along the international value chains that characterise the trade. The case is made that increasingly politicised debates in Europe around risk and uncertainty are potentially counterproductive for EU seafood security and European aquaculture industry, and that the trade in pangasius can contribute to sustainable seafood consumption in a number of ways. Transparent evidence-based assessment and systems for communicating complex issues of risk for products such as pangasius are required in order to support continuance of fair and mutually beneficial trade
What do adolescents with asthma really think about adherence to inhalers? Insights from a qualitative analysis of a UK online forum
ADS is funded by an NIHR Academic Clinical Lectureship. AB is an NIHR
Senior Investigator and additionally was supported by the NIHR Respiratory Disease.
RH was supported by the National Institute for Health Research (NIHR) Collaboration
for Leadership in Applied Health Research (CLAHRC) North Thames at Barts NHS
Trust. The views expressed are those of the author(s) and not necessarily those of
the NHS, NIHR or Department of Health
Spiral-Induced Star Formation in the Outer Disks of Galaxies
The outer regions of galactic disks have received increased attention since
ultraviolet observations with GALEX demonstrated that nearly 30% of galaxies
have UV emission beyond their optical extents, indicating star formation
activity. These galaxies have been termed extended UV (XUV) disks. Here, we
address whether these observations contradict the gas surface density threshold
for star formation inferred from Halpha radial profiles of galaxies. We run
smoothed particle hydrodynamics simulations of isolated disk galaxies with
fiducial star formation prescriptions and show that over-densities owing to the
presence of spiral structure can induce star formation in extended gas disks.
For direct comparison with observations, we use the 3-D radiative transfer code
Sunrise to create simulated FUV and K_s band images. We find that galaxies
classified as Type I XUV disks are a natural consequence of spiral patterns,
but we are unable to reproduce Type II XUV disks. We also compare our results
to studies of the Kennicutt-Schmidt relation in outer disks.Comment: Published in Ap
Simple algebraic data types for C
ADT is a simple tool in the spirit of Lex and Yacc that makes algebraic data types and a restricted form of pattern matching on those data types as found in SML available in C programs. ADT adds runtime checks, which make C programs written with the aid of ADT less likely to dereference a NULL pointer. The runtime tests may consume a significant amount of CPU time; hence they can be switched off once the program is suitably debugged
The new wave of pilot-wave theory
Small drops bouncing across a vibrating liquid bath display many features reminiscent of quantum systems
Mapping kinematic functional abilities of the hand to three dimensional shapes for inclusive design
Loss of hand function can have adverse effects on an individual\u27s ability to maintain independence. The ability to perform daily activities, such as food preparation and medication delivery, is dependent on the hand\u27s ability to grasp and manipulate objects. Therefore, the goal of this research was to demonstrate that three dimensional (3D) modeling of hand function can be used to improve the accessibility of handheld objects for individuals with reduced functionality through informed design. Individual models of hand functionality were created for 43 participants and group models were developed for groups of individuals without (Healthy) and with reduced functionality due to arthritis (RFA) of the hand. Cylindrical models representative of auto-injectors of varying diameters were analyzed in 3D space relative to hand function. The individual model mappings showed the cylinder diameter with the highest mapped functional values varied depending on the type of functional weighting chosen: kinematic redundancy of fingertip pad positional placement, fingertip pad orientation, or finger force directionality. The group mappings showed that for a cylinder to be grasped in a power grasp by at least 75% of the Healthy or RFA groups, a diameter of 40 mm was required. This research utilizes a new hand model to objectively compare design parameters across three different kinematic factors of hand function and across groups with different functional abilities. The ability to conduct these comparisons enables the creation of designs that are universal to all – including accommodation of individuals with limits in their functional abilities
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