878 research outputs found
Approximating Mexican highways with slime mould
Plasmodium of Physarum polycephalum is a single cell visible by unaided eye.
During its foraging behavior the cell spans spatially distributed sources of
nutrients with a protoplasmic network. Geometrical structure of the
protoplasmic networks allows the plasmodium to optimize transport of nutrients
between remote parts of its body. Assuming major Mexican cities are sources of
nutrients how much structure of Physarum protoplasmic network correspond to
structure of Mexican Federal highway network? To find an answer undertook a
series of laboratory experiments with living Physarum polycephalum. We
represent geographical locations of major cities by oat flakes, place a piece
of plasmodium in Mexico city area, record the plasmodium's foraging behavior
and extract topology of nutrient transport networks. Results of our experiments
show that the protoplasmic network formed by Physarum is isomorphic, subject to
limitations imposed, to a network of principle highways. Ideas and results of
the paper may contribute towards future developments in bio-inspired road
planning
Relative contribution of effects included in contemporary groups for adjusted and actual 120-day and 210-day weights in Nelore cattle in Brazil
The objective of this research was to estimate the relative magnitude of effects included in contemporary groups (CG) and their interactions with adjusted and actual 120 d and 210 d weights in 72,731 male and female Nelore calves born from 1985 to 2005 in 40 herds from PMGRN (Genetic Improvement Program of Nelore). Ten models with different CG structures were compared. The analyses were done using the general linear models (GLM) procedure run in SAS software. All of the effects included in the CG for each model were significant (p < 0.001) for the four traits analyzed. Inclusion of semester or trimester of birth as part of a CG was more appropriate than its use as an independent effect in the model because it accounted for interactions with the other effects in the CG. Calf sex (CS) and dam age at calving (DAC) had similar effects across the models, which suggested independence from other effects in these models. The corresponding age deviation effect had a larger impact on actual weight at 120 d than any other effect in all of the models tested. The use of actual weights in models with no CS effect in CG provides an alternative that would allow better genetic connectedness among CGs and greater accuracy in genetic evaluations
Control of intestinal stem cell function and proliferation by mitochondrial pyruvate metabolism.
Most differentiated cells convert glucose to pyruvate in the cytosol through glycolysis, followed by pyruvate oxidation in the mitochondria. These processes are linked by the mitochondrial pyruvate carrier (MPC), which is required for efficient mitochondrial pyruvate uptake. In contrast, proliferative cells, including many cancer and stem cells, perform glycolysis robustly but limit fractional mitochondrial pyruvate oxidation. We sought to understand the role this transition from glycolysis to pyruvate oxidation plays in stem cell maintenance and differentiation. Loss of the MPC in Lgr5-EGFP-positive stem cells, or treatment of intestinal organoids with an MPC inhibitor, increases proliferation and expands the stem cell compartment. Similarly, genetic deletion of the MPC in Drosophila intestinal stem cells also increases proliferation, whereas MPC overexpression suppresses stem cell proliferation. These data demonstrate that limiting mitochondrial pyruvate metabolism is necessary and sufficient to maintain the proliferation of intestinal stem cells
Forest as Stronghold of Local Ecological Practice: Currently Used Wild Food Plants in Polesia, Northern Ukraine
Local ecological practice (LEP, e.g., the everyday practice of collecting and using plants, including wild food plants) is shaped by nature (available local resources) and culture (local perceptions and knowledge on their usability), including a multitude of factors, among which language and geographical or cultural separation have been found to play crucial roles in affecting biocultural diversity. Also, proximity to the forest has been shown to increase the use of plants. We conducted ethnobotanical fieldwork within eastern and western regions of Ukrainian Polesia, during which we interviewed 118 people. Through semi-structured interviews, we recorded the distribution of the current uses of 70 wild food taxa. The analysis of use records revealed homogeneous distribution of use despite the geographical distance and different spoken dialects; however, we were able to single out the highly sylvan region of eastern Polesia as the area with highest biocultural diversity for the use of wild food plants. The results suggest that in the context of the overall homogenization of local ecological knowledge, the continued existence of unintended contact with nature through living and working in the forest may be the primary factor maintaining the broader LEP in the sylvan area of eastern Polesia. Місцева екологічна практика (MЕП, що включає повсякденну практику збору та використання дикорослих рослин у їжу) формується природою (місцевими ресурсами) та культурою (місцеві знання про їх використання), що включає безліч чинників, серед яких мова та географічне або культурне відокремлення відіграють вирішальну роль у впливі на біокультурне різноманіття. Також показано, що близькість до лісу збільшує використання рослин. Ми проводили етноботанічні польові роботи у двох областях Українського Полісся, в ході яких ми провели інтерв’ю з 118 людьми. За допомогою напівструктурованих інтерв’ю ми задокументували поточне використання 70 таксонів дикорослих рослин у їжу. Аналіз записів про вживання свідчить про однорідний розподіл використання, незважаючи на географічне розташування та різні розмовні діалекти; однак, ми змогли виділити лісистий регіон Східного Полісся як територію з найвищим біокультурним різноманіттям використання дикорослих рослин уїжу. Результати свідчать, що в контексті загальної гомогенізації місцевих екологічних знань, продовження існування контакту з природою живучи та працюючи в лісі може бути основним чинником, який підтримує ширшу MЕПу в лісовій зоні Східного Полісся
Spatial Patterns of Parrotfish Corallivory in the Caribbean: The Importance of Coral Taxa, Density and Size
The past few decades have seen an increase in the frequency and intensity of disturbance on coral reefs, resulting in shifts in size and composition of coral populations. These changes have lead to a renewed focus on processes that influence demographic rates in corals, such as corallivory. While previous research indicates selective corallivory among coral taxa, the importance of coral size and the density of coral colonies in influencing corallivory are unknown. We surveyed the size, taxonomy and number of bites by parrotfish per colony of corals and the abundance of three main corallivorous parrotfish (Sparisoma viride, Sparisoma aurofrenatum, Scarus vetula) at multiple spatial scales (reefs within islands: 1–100 km, and between islands: >100 km) within the Bahamas Archipelago. We used a linear mixed model to determine the influence of coral taxa, colony size, colony density, and parrotfish abundance on the intensity of corallivory (bites per m2 of coral tissue). While the effect of colony density was significant in determining the intensity of corallivory, we found no significant influence of colony size or parrotfish abundance (density, biomass or community structure). Parrotfish bites were most frequently observed on the dominant species of reef building corals (Montastraea annularis, Montastraea faveolata and Porites astreoides), yet our results indicate that when the confounding effects of colony density and size were removed, selective corallivory existed only for the less dominant Porites porites. As changes in disturbance regimes result in the decline of dominant frame-work building corals such as Montastraea spp., the projected success of P. porites on Caribbean reefs through high reproductive output, resistance to disease and rapid growth rates may be attenuated through selective corallivory by parrotfish
Performance of two questionnaires to measure treatment adherence in patients with Type-2 Diabetes
<p>Abstract</p> <p>Background</p> <p>Most valid methods to measure treatment adherence require time and resources, and they are not easily applied in highly demanding Primary Health Care Clinics (PHCC). The objective of this study was to determine sensitivity, specificity, predictive values, likelihood ratios, and post-test probabilities of two novel questionnaires as proxy measurements of treatment adherence in Type-2 diabetic patients.</p> <p>Methods</p> <p>Two questionnaires were developed by a group of experts to identify the patient's medical prescription knowledge (knowledge) and their attitudes toward treatment adherence (attitudes) as proxy measurements of adherence. The questionnaires were completed by patients receiving care in PHCC pertaining to the Mexican Institute of Social Security in Aguascalientes (Mexico). Pill count was used as gold standard. Participants were selected randomly, and their oral hypoglycemic prescriptions were studied. The main outcome measures for each questionnaire were sensitivity, specificity, predictive values, likelihood ratios, and post-test probabilities, all as an independent questionnaire test and in a serial analysis.</p> <p>Results</p> <p>Adherence prevalence was 27.0% using pill count. Knowledge questionnaire showed the highest sensitivity (68.1%) and negative predictive value (82.2%), the lowest negative likelihood ratio (0.58) and post-test probability for a negative result (0.16). Serial analysis showed the highest specificity (77.4%) and positive predictive value (40.1%) as well as the highest positive likelihood ratio (1.8) and post-test probability for a positive result (0.39).</p> <p>Conclusion</p> <p>Medical Prescription Knowledge questionnaire showed the best performance as proxy measurement to identify non-adherence in type 2 diabetic patients regarding negative predictive value, negative likelihood ratio, and post-test probability for a negative result. However, Medical Prescription Knowledge questionnaire performance may change in contexts with higher adherence prevalence. Therefore, more research is needed before using this method in other contexts.</p
Hybrid method for selection of the optimal process of leachate treatment in waste treatment and valorization plants or landfills
“The final publication is available at Springer via http://dx.doi.org/10.1007/s10098-014-0834-4”Leachate from waste landfill or treatment plants is a very complex and highly contaminated liquid effluent. In its composition, it is found dissolved organic matter, inorganic salts, heavy metals, and other xenobiotic organic compounds, so it can be toxic, carcinogenic, and capable of inducing a potential risk to biota and humans. European law does not allow such leachate to leave the premises without being depolluted. There are many procedures that enable debugging, always combining different techniques. Choosing the best method to use in each case is a complex decision, as it depends on many tangible and intangible factors that must be weighed to achieve a balance between technical, cost, and environmental sustainability. It is presenting a hybrid method for choosing the optimal combination of techniques to apply in each case, by combining a multicriteria hierarchical analysis based on expert data obtained by the Delphi method with an analysis by the method of VIKOR to reach a consensus solution.Martín Utrillas, MG.; Reyes Medina, M.; Curiel Esparza, J.; Cantó Perelló, J. (2015). Hybrid method for selection of the optimal process of leachate treatment in waste treatment and valorization plants or landfills. Clean Technologies and Environmental Policy. 17(4):873-885. doi:10.1007/s10098-014-0834-4S873885174Abbas AA, Guo J, Ping LZ, Ya PY, Al-Rekabi WS (2009) Review on landfill leachate treatments. AJAS 6(4):672–684Abood AR, Bao J, Abudi Z, Zheng D, Gao C (2013) Pretreatment of nonbiodegradable landfill leachate by air stripping coupled with agitation as ammonia stripping and coagulation–flocculation processes. Clean Technol Environ Policy 15(6):1069–1076Ahn WY, Kang MS, Yim SK, Choi KH (2002) Advanced landfill leachate treatment using an integrated membrane process. Desalination 149(1–3):109–114Al-Subhi Al-Harbi KM (2001) Application of the AHP in project management. Int J Proj Manag 19:19–27Bernasconi M, Choirat C, Seri R (2014) Empirical properties of group preference aggregation methods employed in AHP: theory and evidence. Eur J Oper Res 232(3):584–592Boopathy R, Karthikeyan S, Mandal AB, Sekaran G (2013) Characterization and recovery of sodium chloride from salt-laden solid waste generated from leather industry. Clean Technol Environ Policy 15(1):117–124Brechet T, Tulkens H (2009) Beyond BAT: selecting optimal combinations of available techniques, with an example from the limestone industry. J Environ Manag 90:1790–1801Canto-Perello J, Curiel-Esparza J, Calvo V (2013) Criticality and threat analysis on utility tunnels for planning security policies of utilities in urban underground space. Expert Syst Appl 40(11):4707–4714Chen Y, Liu C, Nie J, Wu S, Wang D (2014) Removal of COD and decolorizing from landfill leachate by Fenton’s reagent advanced oxidation. Clean Technol Environ Policy 16(1):189–193Chiochetta CG, Goetten LC, Almeida SM, Quaranta G, Cotelle S, Radetski CM (2014) Leachates from solid wastes: chemical and eco(geno)toxicological differences between leachates obtained from fresh and stabilized industrial organic sludge. Environ Sci Pollut R 21:1090–1098Chiumenti A, da Borso F, Chiumenti R, Teri F, Segantin P (2013) Treatment of digestate from a co-digestion biogas plant by means of vacuum evaporation: tests for process optimization and environmental sustainability. Waste Manag 33(6):1339–1344Council Directive 1999/31/EC (1999) April 26th 1999, on the landfill of waste. European Union Council, Official Journal L 182, 16/07/1999 P. 0001–0019Curiel-Esparza J, Canto-Perello J (2012) Understanding the major drivers for implementation of municipal sustainable policies in underground space. Int J Sust Dev World 19(6):506–514Curiel-Esparza J, Canto-Perello J (2013) Selecting utilities placement techniques in urban underground engineering. Arch Civ Mech Eng 13(2):276–285Curiel-Esparza J, Canto-Perello J, Calvo MA (2004) Establishing sustainable strategies in urban underground engineering. Sci Eng Ethics 10(3):523–530Dong Y, Zhang G, Hong WC, Xu Y (2010) Consensus models for AHP group decision making under row geometric mean prioritization method. Decis Support Syst 49:281–289Duckstein L, Opricovic S (1980) Multiobjective Optimization in River Basin Development. Water Resour Res 16(1):14–20Ersahin ME, Ozgun H, van Lier JB (2013) Effect of support material properties on dynamic membrane filtration performance. Separ Sci Technol 48(15):2263–2269Gracht HA (2012) Consensus measurement in Delphi studies, review and implications for future quality assurance. Forecast Soc Chang 79(8):1525–1536Grisey E, Laffray X, Contoz O, Cavalli E, Mudry J, Aleya L (2012) The bioaccumulation performance of reeds and cattails in a constructed treatment wetland for removal of heavy metals in landfill leachate treatment (Etueffont, France). Water Air Soil Pollut 223:1723–1741Guoliang Z, Lei Q, Qin M, Zheng F, Dexin W (2013) Aerobic SMBR/reverse osmosis system enhanced by Fenton oxidation for advanced treatment of old municipal landfill leachate. Bioresour Technol 142:261–268Gupta SK, Singh G (2007) Assessment of the Efficiency and Economic Viability of Various Methods of Treatment of Sanitary Landfill Leachate. Environ Monit Assess 135:107–117Heyer KU, Stegmann R (2005) Landfill systems, sanitary landfilling of solid wastes, and long-term problems with leachate. In: Jördening HJ, Winter J (eds) Environmental Biotechnology. Wiley-VCH, Weinheim, p 375Hsu CC, Sandord BA (2007) The Delphi technique: making sense of consensus. PARE 12(10):1–7Kjeldsen P, Barlaz MA, Rooker AP, Baun A, Ledin A, Christensen TH (2002) Present and long-term composition of MSW landfill leachate: a review. Crit Rev Environ Sci Technol 32(4):297–336Lee WS (2013) Merger and acquisition evaluation and decision making model. Serv Ind J 33(15–16):1473–1494Lee GKL, Chan EHW (2008) The analytic hierarchy process (AHP) approach for assessment of urban renewal proposals. Soc Indic Res 89(1):155–168Li G, Wang W, Du Q (2010) Applicability of nanofiltration for the advanced treatment of landfill leachate. J Appl Polym Sci 116(4):2343–2347Mela K, Tiainen T, Heinisuo M (2012) Comparative study of multiple criteria decision making methods for building design. Adv Eng Inform 26:716–726Ozdemir MS, Saaty TL (2006) The unknown in decision making, what to do about it. Eur J Oper Res 174(1):349–359Renou S, Givaudan JG, Poulain S, Dirassouyan F, Moulin P (2008) Landfill leachate treatment: review and opportunity. J Hazard Mater 150(3):468–493Ritzkowski M, Stegmann R (2012) Landfill aeration worldwide: concepts, indications and findings. Waste Manag 32(7):1411–1419Romero C, Ramos P, Costa C, Marquez MC (2013) Raw and digested municipal waste compost leachate as potential fertilizer: comparison with a commercial fertilizer. J Clean Prod 59:73–78Roubelat F (2011) The Delphi method as a ritual: inquiring the Delphi Oracle. Forecast Soc Chang 78(9):1491–1499Saaty TL (1980) The analytic hierarchy process. Mc Graw-Hill, New YorkSaaty TL (2001) Decision making with dependence and feedback: the analytic network process, 2nd edn. RWS Publications, PittsburghSaaty TL (2008) Decision making with the analytic hierarchy process. Int J Serv Sci 1(1):83–98Saaty TL (2012) Decision making for leaders. The analytic hierarchy process for decisions in a complex world, 3rd edn. RWS Publications, PittsburghSan Cristobal J (2012) Contractor selection using multicriteria decision-making methods. J Constr Eng M 138(6):751–758Sayadi MK, Heydari M, Shahanaghi K (2009) Extension of VIKOR method for decision making problem with interval numbers. Appl Math Model 33:2257–2262Statnikova RB, Bordetskya A, Statnikov A (2005) Multi-criteria analysis of real-life engineering optimization problems: statement and solution. Nonlinear Anal 63:685–696Syamsuddin J (2010) The use of AHP in security policy decision making: an open office calc application. JSW 5(10):1162–1169Thapa RB, Murayama Y (2010) Drivers of urban growth in the Kathmandu valley, Nepal: examining the efficacy of the analytic hierarchy process. App Geogr 30(1):70–83van Praagh M, Heerenklage J, Smidt E, Modin H, Stegmann R, Persson KM (2009) Potential emissions from two mechanically–biologically pretreated (MBT) wastes. Waste Manag 29(2):859–868Vedaraman N, Shamshath BS, Srinivasan SV (2013) Response surface methodology for decolourisation of leather dye using ozonation in a packed bed reactor. Clean Technol Environ Policy 15(4):607–616Wang Q, Matsufuji Y, Dong L, Huang Q, Hirano F, Tanaka A (2006) Research on leachate recirculation from different types of landfills. Waste Manag 26:815–824Xing W, Lu W, Zhao Y (2013) Environmental impact assessment of leachate recirculation in landfill of municipal solid waste by comparing with evaporation and discharge (EASEWASTE). Waste Manag 33(2):382–389Yang W, Zhang KN, Chen YG, Zhou XZ, Jin FX (2013) Prediction on contaminant migration in aquifer of fractured granite substrata of landfill. J Cent South Univ 20(11):3193–3201Zavadskas EK, Turskis Z, Tamosaitiene J (2011) Selection of construction enterprises management strategy based on SWOT and multi-criteria analysis. ACME 11(4):1063–108
Reprogramming of Escherichia coli K-12 Metabolism during the Initial Phase of Transition from an Anaerobic to a Micro-Aerobic Environment
Background: Many bacteria undergo transitions between environments with differing O2 availabilities as part of their natural lifestyles and during biotechnological processes. However, the dynamics of adaptation when bacteria experience changes in O2 availability are understudied. The model bacterium and facultative anaerobe Escherichia coli K-12 provides an ideal system for exploring this process.
Methods and Findings: Time-resolved transcript profiles of E. coli K-12 during the initial phase of transition from anaerobic to micro-aerobic conditions revealed a reprogramming of gene expression consistent with a switch from fermentative to respiratory metabolism. The changes in transcript abundance were matched by changes in the abundances of selected central metabolic proteins. A probabilistic state space model was used to infer the activities of two key regulators, FNR (O2 sensing) and PdhR (pyruvate sensing). The model implied that both regulators were rapidly inactivated during the transition from an anaerobic to a micro-aerobic environment. Analysis of the external metabolome and protein levels suggested that the cultures transit through different physiological states during the process of adaptation, characterized by the rapid inactivation of pyruvate formate-lyase (PFL), a slower induction of pyruvate dehydrogenase complex (PDHC) activity and transient excretion of pyruvate, consistent with the predicted inactivation of PdhR and FNR.
Conclusion: Perturbation of anaerobic steady-state cultures by introduction of a limited supply of O2 combined with time-resolved transcript, protein and metabolite profiling, and probabilistic modeling has revealed that pyruvate (sensed by PdhR) is a key metabolic signal in coordinating the reprogramming of E. coli K-12 gene expression by working alongside the O2 sensor FNR during transition from anaerobic to micro-aerobic conditions
The Perceived Benefits of Height: Strength, Dominance, Social Concern, and Knowledge among Bolivian Native Amazonians
Research in industrial countries suggests that, with no other knowledge about a person, positive traits are attributed to taller people and correspondingly, that taller people have slightly better socioeconomic status (SES). However, research in some non-industrialized contexts has shown no correlation or even negative correlations between height and socioeconomic outcomes. It remains unclear whether positive traits remain attributed to taller people in such contexts. To address this question, here we report the results of a study in a foraging-farming society of native Amazonians in Bolivia (Tsimane’)–a group in which we have previously shown little association between height and socioeconomic outcomes. We showed 24 photographs of pairs of Tsimane’ women, men, boys, and girls to 40 women and 40 men >16 years of age. We presented four behavioral scenarios to each participant and asked them to point to the person in the photograph with greater strength, dominance, social concern, or knowledge. The pairs in the photographs were of the same sex and age, but one person was shorter. Tsimane’ women and men attributed greater strength, dominance, and knowledge to taller girls and boys, but they did not attribute most positive traits to taller adults, except for strength, and more social concern only when women assessed other women in the photographs. These results raise a puzzle: why would Tsimane’ attribute positive traits to tall children, but not tall adults? We propose three potential explanations: adults’ expectations about the more market integrated society in which their children will grow up, height as a signal of good child health, and children’s greater variation in the traits assessed corresponding to maturational stages
Effective Rheology of Bubbles Moving in a Capillary Tube
We calculate the average volumetric flux versus pressure drop of bubbles
moving in a single capillary tube with varying diameter, finding a square-root
relation from mapping the flow equations onto that of a driven overdamped
pendulum. The calculation is based on a derivation of the equation of motion of
a bubble train from considering the capillary forces and the entropy production
associated with the viscous flow. We also calculate the configurational
probability of the positions of the bubbles.Comment: 4 pages, 1 figur
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