Powerful fish in poor environments: Energetic trade-offs drive distribution and abundance in an extremophile forest-dwelling fish

For many species, distribution and abundance is driven by a trade-off between abiotic and biotic stress tolerance (i.e. physical stress versus competition or predation stress). This trade- off may be caused by metabolic rate differences in species such that slow metabolic rates increase abiotic tolerance but decrease biotic tolerance. I investigated how metabolic rate differences were responsible for an abiotic-biotic tolerance trade-off in brown mudfish (Neochanna apoda) and banded kokopu (Galaxias fasciatus), that drives the allopatric distribution of these fish in podocarp swamp-forest pools. Brown mudfish and banded kokopu distribution across 65 forest pools in Saltwater forest, Westland National Park, New Zealand was almost completely allopatric. Mudfish were restricted to pools with extreme abiotic stress including hypoxia, acidity and droughts because of kokopu predation in benign pools. This meant the mudfish realised niche was only a small fraction of their large fundamental niche, which was the largest out of sixteen freshwater fish species surveyed in South Island West Coast habitats. Thus mudfish had a large fundamental to realised niche ratio because of strong physiological stress tolerance but poor biotic stress tolerance compared to other fish. A low metabolic capacity in mudfish compared to kokopu in terms of resting and maximum metabolic rates and aerobic scope explained the strong mudfish tolerance to extreme abiotic stress, but also their sensitivity to biotic stress by more powerful kokopu in benign pools, and hence their allopatric distribution with kokopu. Despite being restricted to extreme physical stress, mudfish populations were, in fact, more dense than those of kokopu, because of low individual mudfish resting metabolic rates, which would cause resources to be divided over more individuals. Distribution and abundance in mudfish and kokopu were therefore driven by an abiotic-biotic tolerance trade-off caused by a physiological trade-off between having slow or fast metabolic rates, respectively. The negative relationship between species resting metabolic rates and their tolerance to abiotic stress provides a way of estimating the impact of human induced environmental change that can either increase or decrease habitat harshness. Thus species with low metabolic rates, like mudfish, will be negatively affected by human induced environmental change that removes abiotic habitat stress and replaces it with benign conditions. My evidence shows that extreme stressors provide a protective habitat supporting high mudfish biomass with significant conservation value that should be maintained for the long-term persistence of mudfish populations

Economics of Drip Irrigation for Juice Grape Vineyards in New York State

R.B. 99-01Grape growers need investment and cost guidelines for drip irrigation to evaluate the economics of getting vines into production as quickly as possible and to avoid periods of drought during the productive life of the vineyard. The benefits of irrigation may include: better vine survival, earlier fruit production, greater yields, more efficient distribution of nutrients, less plant stress, reduced yield variability and improved fruit quality. Research was undertaken to determine drip irrigation investment and annual costs. This project was designed to assist growers in determining the investment, fixed and variable annual costs and expected returns from drip irrigation. Irrigation suppliers provided typical equipment needs and investment costs for various drip irrigation designs. Economic worksheets are provided to assist growers in estimating fixed and variable costs of drip irrigation. The economics of yield data were applied to replicated multiyear irrigation studies to assist growers in determining yield response from drip irrigation. Net present value (NPV) methodology was used to determine the discounted break-even investment results from published responses to drip irrigation. Growers with typical drip irrigation systems and various water sources can expect investments in drip irrigation of $550 to$1,150 per acre with 10 acre blocks of vines. Based upon eight years of data from trials in Fredonia, NY, in the Lake Erie grape belt, average yield increases due to irrigation on establishment and growing of Niagara grapes were 2.8 ton per production year per acre, resulting in a break-even investment of approximately $1,600 per acre. But on established minimal pruned Concord grapes, seven years of data showed a 1.1 ton increase due to irrigation and a break-even investment of only$200 per acre which was well below the total cost of a complete microirrigation drip system. On a new planting of Concords, with droughty soils, the analysis may very well show cost effectiveness. Growers who were interviewed were unable to quantify the benefits and costs of drip irrigation but were pleased with their irrigated yields and brix responses from drip irrigation. This analysis has provided the economic rationale for the investment in microirrigation with some varieties and under certain soil types

Measuring aortic pulse wave velocity using high-field cardiovascular magnetic resonance: comparison of techniques

<p>Abstract</p> <p>Background</p> <p>The assessment of arterial stiffness is increasingly used for evaluating patients with different cardiovascular diseases as the mechanical properties of major arteries are often altered. Aortic stiffness can be noninvasively estimated by measuring pulse wave velocity (PWV). Several methods have been proposed for measuring PWV using velocity-encoded cardiovascular magnetic resonance (CMR), including transit-time (TT), flow-area (QA), and cross-correlation (XC) methods. However, assessment and comparison of these techniques at high field strength has not yet been performed. In this work, the TT, QA, and XC techniques were clinically tested at 3 Tesla and compared to each other.</p> <p>Methods</p> <p>Fifty cardiovascular patients and six volunteers were scanned to acquire the necessary images. The six volunteer scans were performed twice to test inter-scan reproducibility. Patient images were analyzed using the TT, XC, and QA methods to determine PWV. Two observers analyzed the images to determine inter-observer and intra-observer variabilities. The PWV measurements by the three methods were compared to each other to test inter-method variability. To illustrate the importance of PWV using CMR, the degree of aortic stiffness was assessed using PWV and related to LV dysfunction in five patients with diastolic heart failure patients and five matched volunteers.</p> <p>Results</p> <p>The inter-observer and intra-observer variability results showed no bias between the different techniques. The TT and XC results were more reproducible than the QA; the mean (SD) inter-observer/intra-observer PWV differences were -0.12(1.3)/-0.04(0.4) for TT, 0.2(1.3)/0.09(0.9) for XC, and 0.6(1.6)/0.2(1.4) m/s for QA methods, respectively. The correlation coefficients (r) for the inter-observer/intra-observer comparisons were 0.94/0.99, 0.88/0.94, and 0.83/0.92 for the TT, XC, and QA methods, respectively. The inter-scan reproducibility results showed low variability between the repeated scans (mean (SD) PWV difference = -0.02(0.4) m/s and r = 0.96). The inter-method variability results showed strong correlation between the TT and XC measurements, but less correlation with QA: r = 0.95, 0.87, and 0.89, and mean (SD) PWV differences = -0.12(1.0), 0.8(1.7), and 0.65(1.6) m/s for TT-XC, TT-QA, and XC-QA, respectively. Finally, in the group of diastolic heart failure patient, PWV was significantly higher (6.3 ± 1.9 m/s) than in volunteers (3.5 ± 1.4 m/s), and the degree of LV diastolic dysfunction showed good correlation with aortic PWV.</p> <p>Conclusions</p> <p>In conclusion, while each of the studied methods has its own advantages and disadvantages, at high field strength, the TT and XC methods result in closer and more reproducible aortic PWV measurements, and the associated image processing requires less user interaction, than in the QA method. The choice of the analysis technique depends on the vessel segment geometry and available image quality.</p

Transmission potential of Rift Valley fever virus over the course of the 2010 epidemic in South Africa.

A Rift Valley fever (RVF) epidemic affecting animals on domestic livestock farms was reported in South Africa during January-August 2010. The first cases occurred after heavy rainfall, and the virus subsequently spread countrywide. To determine the possible effect of environmental conditions and vaccination on RVF virus transmissibility, we estimated the effective reproduction number (Re) for the virus over the course of the epidemic by extending the Wallinga and Teunis algorithm with spatial information. Re reached its highest value in mid-February and fell below unity around mid-March, when vaccination coverage was 7.5%-45.7% and vector-suitable environmental conditions were maintained. The epidemic fade-out likely resulted first from the immunization of animals following natural infection or vaccination. The decline in vector-suitable environmental conditions from April onwards and further vaccination helped maintain Re below unity. Increased availability of vaccine use data would enable evaluation of the effect of RVF vaccination campaigns

Density and Velocity Fields from the PSCz Survey

We present the results for the predicted density and peculiar velocity fields and the dipole from the PSCz survey of 15,000 IRAS galaxies over 84% of the sky. We find a significant component to the dipole arising between 6000 and 15,000 km/s, but no significant component from greater distances. The misalignment with the CMB is 20 degrees. The most remarkable feature of the PSCz model velocity field is a coherent large-scale flow along the baseline connecting Perseus-Pisces, the Local Supercluster, Great Attractor and the Shapley Concentration. We have measured the parameter beta using the amplitude of the dipole, bulk flow and point by point comparisons between the individual velocities of galaxies in the MarkIII and SFI datasets, and the large-scale clustering distortion in redshift space.All our results are consistent with beta = 0.6 +- 0.1.Comment: 8 pages, 8 figures. To appear in 'Towards an Understanding of Cosmic Flows', Victoria, July 1999, eds Courteau,S., Strauss,M., Willick,J. PAS

The High Impact of Astronomical Data Archives

Archives are widely recognized as a valuable resource for astronomy, but statistics on their use indicates they are even more important than most astronomers realize. Obviously much of the science from survey projects such as SDSS relies on the archive. Perhaps more surprisingly, archival data are also a major contributor to the science from targeted, PI-driven missions such as HST, Chandra, Spitzer and the ground-based observatories. Archival research currently accounts for half of the ~1200 Hubble and Chandra science papers published each year, and the use of the archive continues to increase. The archival data products are, in the long term, as important as the PI science programs. It is vital to recognize the large impact archives can have on the science generated by missions and observatories. The value of the archive should be an important factor in the establishment of new projects. Future missions and observatories should not only budget adequate resources to support a robust archive, but they also should consider the effects of mission design and operations decisions on the archive. Additional funding both for archive users and archive centers -- particularly with an eye to enabling cross-archive, multiwavelength science -- is a relatively inexpensive way to increase the science output from our major investments in large projects

Laparoscopic motor learning and workspace exploration

Background: Laparoscopic surgery requires operators to learn novel complex movement patterns. However, our understanding of how best to train surgeons’ motor skills is inadequate and research is needed to determine optimal laparoscopic training regimes. This difficulty is confounded by variables inherent in surgical practice – e.g. the increasing prevalence of morbidly obese patients presents additional challenges related to restriction of movement due to abdominal wall resistance and reduced intra-abdominal space. The aim of this study was to assess learning of a surgery related task in constrained and unconstrained conditions using a novel system linking a commercially available robotic arm with specialised software creating the novel kinematic assessment tool (Omni-KAT). Methods: We created an experimental tool that records motor performance by linking a commercially available robotic arm with specialised software that presents visual stimuli and objectively measures movement outcome (kinematics). Participants were given the task of generating aiming movements along a horizontal plane to move a visual cursor on a vertical screen. One group received training that constrained movements to the correct plane whilst the other group was unconstrained and could explore the entire ‘action space’. Results: The tool successfully generated the requisite force fields and precisely recorded the aiming movements. Consistent with predictions from structural learning theory, the unconstrained group produced better performance after training as indexed by movement duration (p < .05). Conclusion: The data showed improved performance for participants who explored the entire action space, highlighting the importance of learning the full dynamics of laparoscopic instruments. These findings, alongside the development of the Omni-KAT, open up exciting prospects for better understanding of the learning processes behind surgical training and investigating ways in which learning can be optimised

The Problem with Big Data: Operating on Smaller Datasets to Bridge the Implementation Gap

Big datasets have the potential to revolutionize public health. However, there is a mismatch between the political and scientific optimism surrounding big data and the public’s perception of its benefit. We suggest a systematic and concerted emphasis on developing models derived from smaller datasets to illustrate to the public how big data can produce tangible benefits in the long term. In order to highlight the immediate value of a small data approach, we produced a proof-of-concept model predicting hospital length of stay. The results demonstrate that existing small datasets can be used to create models that generate a reasonable prediction, facilitating health-care delivery. We propose that greater attention (and funding) needs to be directed toward the utilization of existing information resources in parallel with current efforts to create and exploit “big data.

Europe’s men need their own health strategy

Ten years ago the BMJ published a special issue on men’s health. It noted how, although men fare better than women in most conventional measures such as top jobs and earnings, this advantage is not reflected in their health. A report we produced this summer, The State of Men’s Health in Europe, shows that little has changed. At any given age, men are still more likely than women to die from most of the leading causes, and in the European Union men have more than twice as many deaths a year as women throughout the working ages (15-64 years). This high level of premature mortality in men has psychological, social, and economic consequences for relatives, households, communities, and the workplace. Yet, in both national and European health policy, men and “masculinity” are largely taken for granted. This has limited the development of evidence based programmes that meet their health needs