98 research outputs found

    Genome architecture enables local adaptation of Atlantic cod despite high connectivity

    Get PDF
    Adaptation to local conditions is a fundamental process in evolution; however, mechanisms maintaining local adaptation despite high gene flow are still poorly understood. Marine ecosystems provide a wide array of diverse habitats that frequently promote ecological adaptation even in species characterized by strong levels of gene flow. As one example, populations of the marine fish Atlantic cod (Gadus morhua) are highly connected due to immense dispersal capabilities but nevertheless show local adaptation in several key traits. By combining population genomic analyses based on 12K single nucleotide polymorphisms with larval dispersal patterns inferred using a biophysical ocean model, we show that Atlantic cod individuals residing in sheltered estuarine habitats of Scandinavian fjords mainly belong to offshore oceanic populations with considerable connectivity between these diverse ecosystems. Nevertheless, we also find evidence for discrete fjord populations that are genetically differentiated from offshore populations, indicative of local adaptation, the degree of which appears to be influenced by connectivity. Analyses of the genomic architecture reveal a significant overrepresentation of a large ~5 Mb chromosomal rearrangement in fjord cod, previously proposed to comprise genes critical for the survival at low salinities. This suggests that despite considerable connectivity with offshore populations, local adaptation to fjord environments may be enabled by suppression of recombination in the rearranged region. Our study provides new insights into the potential of local adaptation in high gene flow species within fine geographical scales and highlights the importance of genome architecture in analyses of ecological adaptation

    Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

    Get PDF
    Peer reviewe

    Search for microscopic black hole signatures at the Large Hadron Collider

    Get PDF
    This is the Pre-Print version of the Article. The official published paper can be accessed from the link below - Copyright @ 2011 ElsevierA search for microscopic black hole production and decay in pp collisions at a center-of-mass energy of 7 TeV has been conducted by the CMS Collaboration at the LHC, using a data sample corresponding to an integrated luminosity of 35 inverse picobarns. Events with large total transverse energy are analyzed for the presence of multiple high-energy jets, leptons, and photons, typical of a signal expected from a microscopic black hole. Good agreement with the expected standard model backgrounds, dominated by QCD multijet production, is observed for various final-state multiplicities. Limits on the minimum black hole mass are set, in the range 3.5 -- 4.5 TeV, for a variety of parameters in a model with large extra dimensions, along with model-independent limits on new physics in these final states. These are the first direct limits on black hole production at a particle accelerator.This work is supported by the FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

    Evaluating the Efficiency of Wicking Bed Irrigation Systems for Small-Scale Urban Agriculture

    No full text
    A wicking bed (WB) is a plant driven system where plants receive water through capillary rise from a self-contained coarse material-filled subsoil reservoir. WBs have been widely promoted as a water-efficient irrigation solution for small-scale and urban food gardens. However, little published research exists to support popular claims about their effectiveness. In this study, the performance of WBs was compared with best-practice, precision surface irrigation in terms of water use efficiency (WUE), fruit yield, fruit quality and labour input, using tomato (Solanum lycopersicum) as the experimental crop. The influence of WB design variables (reservoir depths and soil bed depths) was tested. Results showed that WBs performed as well or better than precision surface irrigated pots, showing statistically significant improvement in WUE, yield and fruit quality. The results also suggest an optimum design exists for soil depth (where 300 mm outperformed 600 mm) but not reservoir depth (no difference between 150 and 300 mm). The WBs were more labour efficient, requiring significantly less frequent watering to achieve the same or better WUE. WBs are inherently low-tech and scalable and appear well-suited to a variety of urban agriculture settings

    Exploring Conventional Economic Viability as a Potential Barrier to Scalable Urban Agriculture: Examples from Two Divergent Development Contexts

    No full text
    Urban Agriculture (UA) is the widespread practice of food production within available city space using non-commercial, commercial and hybrid production technologies. The economic viability of UA remains a concern among UA practitioners. To investigate UA’s viability; land, labour and distribution cost are analyzed, and margin and benefit–cost ratio (BCR) under vacant lot, rooftop/backyard and discretionary labour UA are calculated. We present a straightforward approach to gauge the economic viability of UA taking examples from 40 distinct locations of two divergent development contexts of Adelaide, South Australia and Kathmandu Valley, Nepal. UA seems potentially viable by selecting high-value crops in Adelaide but showed little chance of viability under low-value crop scenarios in both contexts. The high cost of land is shown to be the primary driver of cost for UA. Labour cost appears to be a critical difference between the two cities, being an important constraint for the economic viability in Adelaide, where the wage rate is high. To improve economic viability, the respective governments and planners should consider better ways to avail subsidised land through policy intervention and volunteer or subsidised labour arrangement mechanisms. Home food gardens accessing available land and labour as a discretionary/spare time activity with zero distribution cost may represent the best way to produce food without exceeding market costs in cities

    Modelling the Benefits and Impacts of Urban Agriculture: Employment, Economy of Scale and Carbon Dioxide Emissions

    No full text
    This paper examines the social, economic and environmental potential of Urban Agriculture (UA) based on information from forty distinct locations in each of the two regions: Adelaide, South Australia and Kathmandu Valley, Nepal, representing the diverse developmental background. Modelling is used to estimate equivalent employment, scale appropriateness, and earnings in comparison to labour use from commercial urban farming and gardening style UA, together with carbon dioxide emissions for two vegetable types. The study investigates the influence of distance and production scale under manual to modest mechanisation for urban vegetable production, finding that the interplay between labour use and mechanisation can favour scale-appropriate UA practices with better labour productivity and economic and social advantage. The distribution (assumed to be by car for UA) contributes the largest proportion of emissions, and the production component (even with mechanisation) contributes a relatively small portion per unit of production. We recommend that governments and planners should facilitate scale-appropriate mechanisation through better planning and policy instruments for UA’s sustainability

    Water Quality Effects of a Water Sensitive Urban Design Retrofit in an Urban Streetscape in Adelaide, Australia

    No full text
    Australian cities are expanding rapidly due to a population growth of 25% over the past 20 years. The development of healthy and sustainable cities has become an increasingly important challenge for urban planners, and integrated approaches to planning and design are currently being sought. One such approach is Water Sensitive Urban Design (WSUD), which incorporates sustainable water management systems and practices into the urban landscape. While there are many case studies on the incorporation of WSUD into greenfield development sites, there are few investigations of the potential for water quality improvement that can be achieved by retrofitting existing developments with WSUD. This study investigates the use of hydrological modelling techniques to quantify the water quality benefits of retrofitting WSUD into an existing streetscape in the Adelaide central business district. The results show a need for enhancing the performance of the current hydrological modelling tools for planning and design of permeable pavements and also a need for developing tools to design bioretention systems. The outcomes of this study will lead to an enhancement of current knowledge on the potential for water quality improvement that can be achieved by using bioretention systems and permeable pavements with underlying storage in urban landscapes.
    • …
    corecore