3,379 research outputs found
Weathering the Storm of Business Climate Rankings
This paper explores current usage of the term business climate. It discusses multiple definitions and measures of what constitutes a region's business climate. It also examines how usage of the term varies over time and geography. Finally, it addresses some issues related to business climate rankings, their role in economic development policy, and whether the multiplicity of published state rankings contribute consensus or confusion to the meaning of the term business climate.
Into the Light: Diurnality has Evolved Multiple Times in Geckos
Geckos are the only major lizard group consisting mostly of nocturnal species. Nocturnality is presumed to have evolved early in gecko evolution and geckos possess numerous adaptations to functioning in low light and at low temperatures. However, not all gecko species are nocturnal and most diurnal geckos have their own distinct adaptations to living in warmer, sunlit environments. We reconstructed the evolution of gecko activity patterns using a newly generated time-calibrated phylogeny. Our results provide the first phylogenetic analysis of temporal activity patterns in geckos and confirm an ancient origin of nocturnality at the root of the gecko tree. We identify multiple transitions to diurnality at a variety of evolutionary time scales and transitions back to nocturnality occur in several predominantly diurnal clades. The scenario presented here will be useful in reinterpreting existing hypotheses of how geckos have adapted to varying thermal and light environments. These results can also inform future research of gecko ecology, physiology, morphology and vision as it relates to changes in temporal activity patterns
SAVMA Symposium 2001: From the Heartland to the World
The Student American Veterinary Medical Association Symposium is coming to Iowa State University March 8, 9, and 10,2001. Students at the ISU College of Veterinary Medicine are excited about the opportunity to showcase our college, university, and the state of Iowa. SAVMA Symposium is an event held annually at one of the 27 Veterinary Colleges in the United States. This event is organized and run by students of the host college. SAVMA Symposium requires a large time and financial commitment from all involved. ISU students are busy preparing to make this the most exciting and educational Symposium ever
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Plant hydraulic traits reveal islands as refugia from worsening drought.
Relatively mesic environments within arid regions may be important conservation targets as 'climate change refugia' for species persistence in the face of worsening drought conditions. Semi-arid southern California and the relatively mesic environments of California's Channel Islands provide a model system for examining drought responses of plants in potential climate change refugia. Most methods for detecting refugia are focused on 'exposure' of organisms to certain abiotic conditions, which fail to assess how local adaptation or acclimation of plant traits (i.e. 'sensitivity') contribute to or offset the benefits of reduced exposure. Here, we use a comparative plant hydraulics approach to characterize the vulnerability of plants to drought, providing a framework for identifying the locations and trait patterns that underlie functioning climate change refugia. Seasonal water relations, xylem hydraulic traits and remotely sensed vegetation indices of matched island and mainland field sites were used to compare the response of native plants from contrasting island and mainland sites to hotter droughts in the early 21st century. Island plants experienced more favorable water relations and resilience to recent drought. However, island plants displayed low plasticity/adaptation of hydraulic traits to local conditions, which indicates that relatively conserved traits of island plants underlie greater hydraulic safety and localized buffering from regional drought conditions. Our results provide an explanation for how California's Channel Islands function as a regional climate refugia during past and current climate change and demonstrate a physiology-based approach for detecting potential climate change refugia in other systems
The SPASE Data Model for Heliophysics Data: Is it Working?
The Space Physics Archive Search and Extract (SPASE) Data Model was developed to provide a metadata standard for describing Heliophysics (Space and Solar Physics) data within that science discipline. The SPASE Data Model has matured over the many years of its creation and is presently represented by Version 2.2.1. Information about SPASE can be obtained from the website group.org. The Data Model defines terms and values as well as the relationships between them in order to describe the data resources in the Heliophysics data environment. This data environment is quite complex, consisting of Virtual Observatories, Resident Archives, Data Providers, Partnering Data Centers, Services, Final Archives, and a Deep Archive. SPASE is the metadata language standard intended to permeate the complexity and provide a common method of obtaining and understanding data. Is it working in this capacity? SPASE has been used to describe a wide range of data. Examples range from ground-based magnetometer data to interplanetary satellite measurements to space weather model results. Has it achieved the goal of making the data easier to find and use? To find data of interest it is necessary that all the data of importance be described using the SPASE Data Model. Within the part of the data community associated with NASA (supported through NASA funding) there are obligations to use SPASE and (0 describe the old and new data using the SPASE XML schema. Although this pan of the community is not near 100% compliance with the mandate, there is good progress being made and the goal should be reachable in the future. Outside of the NASA data community there is still work to be done to convince the international community that SPASE descriptions are w011h the cost of their generation. Some of these groups such as Cluster, HELlO, GAIA, NOAA/NGDe. CSSDP, VSTO, SuperMAG, and IUGONET have agreed to use SPASE. but there are still other groups of importance that need (0 be reached. It is also assumed that the terminology is sufficiently broad and the descriptions are sufficiently complete that researchers needing data of a specific type or from a specific period can find and acquire what they need. A valid SPASE description can be very brief or very thorough depending on the willingness of the author to spend the time necessary to make the description useful. There is evidence that users are finding what they need through the SPASE descriptions, and this standard is a big step forward in Heliophysics data location. Does SPASE make it easier to use the data once they are found,) Thorough descriptions of data using SPASE can describe the data down to the level of individual parameters and exactly how the data are organized and stored. Should the SPASE data descriptions be written in such a way that they can be automatically ingested and understood by software tools'? Heliophysics instruments are becoming morc versatile all the time and the complexity of the data makes it tedious and time consuming to write SPASE descriptions with this level of sophistication even with the improvement of the tools used to generate the descriptions. Is it better to just write human-readable descriptions of the data at the parameter level or to refer to references that provide this information? This is a debate that is presently taking place and software is being developed to test what is possible
Contractile units in disordered actomyosin bundles arise from F-actin buckling
Bundles of filaments and motors are central to contractility in cells. The
classic example is striated muscle, where actomyosin contractility is mediated
by highly organized sarcomeres which act as fundamental contractile units.
However, many contractile bundles in vivo and in vitro lack sarcomeric
organization. Here we propose a model for how contractility can arise in
actomyosin bundles without sarcomeric organization and validate its predictions
with experiments on a reconstituted system. In the model, internal stresses in
frustrated arrangements of motors with diverse velocities cause filaments to
buckle, leading to overall shortening. We describe the onset of buckling in the
presence of stochastic actin-myosin detachment and predict that
buckling-induced contraction occurs in an intermediate range of motor
densities. We then calculate the size of the "contractile units" associated
with this process. Consistent with these results, our reconstituted actomyosin
bundles contract at relatively high motor density, and we observe buckling at
the predicted length scale.Comment: 5 pages, 4 figures, Supporting text and movies attache
Identification and quantification of diffuse groundwater pollution in a mineralised watershed
A tracer injection and synoptic sampling experiment was carried out in a tributary catchment of the River Tywi (Carmarthenshire, Wales) during a very low streamflow event to locate and quantify sources of groundwater metal pollution from the abandoned Nantymwyn Pb mine. High resolution sampling at 22 stream locations and 12 inflows along a 2 km stretch of the Nant y Bai was deployed. This high spatial resolution sampling technique allowed point and diffuse sources of metal pollution to be identified enabling their contribution to the overall stream load to be quantified. It was found that the highest proportion of filtered Zn load originated from diffuse groundwater sources from the upper mine tailings (43%), and that the highest proportion of filtered Pb load originated from diffuse groundwater sources from the lower mine tailings (40%), with smaller inputs from a field on the River Tywi floodplain. These results demonstrate that tracer dilution and synoptic sampling is a powerful tool to locate and apportion diffuse sources of groundwater metal pollution in small, mineralised watersheds
Long-term changes in water quality downstream of three abandoned metal mines
Abandoned metal mines pollute rivers with both acidic and circumneutral metal-rich waters, sometimes from well-mapped mines, but often from long-abandoned adits with limited historical records. Changes in water quality over the monitored timescales were calculated for three mines across Wales (Nantymwyn, Parys Mountain and Frongoch), each abandoned since the early 20th century. Using all available spot sampling data provided by the environmental regulator, it was found that there was a sustained input of metals to the receiving watercourses with no or limited reduction in the concentrations from the mines without remediation, despite the passage of time and impacts of weathering. At Nantymwyn, comparison with five months’ sampling in 2019 showed no significant change (p > 0.05) in metal concentrations compared to the same months in 1985. Parys Mountain showed an increase in filtered zinc concentrations of 2 % between 2004 and 2020. At Frongoch, however, a substantial reduction in its environmental impact was observed after remediation, including a 90 % reduction in total lead concentrations. Realisation that the pollution from these sites does not reduce over the decades since abandonment should galvanize the resolve to understand the highest priority sites, and where possible remediate them
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