13,004 research outputs found
High pCO 2 levels affect metabolic rate, but not feeding behavior and fitness, of farmed giant mussel Choromytilus chorus
IndexaciĂłn: Scopus.Acknowledgements. We thank Luisa Saavedra and Araceli Rodriguez-Romero for their help in the field and during laboratory activities. We also acknowledge Laura Ramajo for help with AT estimations. Emily Giles Neill provided valuable comments that greatly improved the manuscript. Special thanks are due to the reviewers and the editor for very constructive comments on the manuscript. This study was supported by the Millennium Nucleus Center for the Study of Multiple drivers on Marine Socio-Ecological Systems (MUSELS) funded by MINECON NC120086, PIA CONICYT ACT-172037 and FONDECYT grant nos. 1140938 and 1140092 to N.A.L. and M.A.L.Mar Ecol Prog Ser 454: 65â74 Findlay HS, Wood HL, Kendall MA, Spicer JI, Twitchett RJ, Widdicombe S (2009) Calcification, a physiological pro-cess to be considered in the context of the whole organ-ism. Biogeosciences 6: 2267â2284 Fitzer SC, Zhu W, Tanner KE, Phoenix VR, Kamenos NA, Cusack M (2015) Ocean acidification alters the material properties of Mytilus edulis shells. J R Soc Interface 12: 214â227 Freitas R, De Marchi L, Bastos M, Moreira A and others (2017) Effects of seawater acidification and salinity alter-ations on metabolic, osmoregulation and oxidative stress markers in Mytilus galloprovincialis. Ecol Indic 79: 54â62 Gattuso JP, Magnan A, BillĂ© R, Cheung WWL and others (2015) Contrasting futures for ocean and society from dif-ferent anthropogenic CO2 emissions scenarios. Science 349: aac4722 Gazeau F, Urbini L, Cox TE, Alliouane S, Gattuso JP (2015) Comparison of the alkalinity and calcium anomaly tech-niques to estimate rates of net calcification. Mar Ecol Prog Ser 527: 1â12 Gray MW, Langdon CJ, Waldbusser GG, Hales B, Kramer S (2017) Mechanistic understanding of ocean acidification impacts on larval feeding physiology and energy budg-ets of the mussel Mytilus californianus. Mar Ecol Prog Ser 563: 81â94 Griffiths CL, Griffiths RJ (1987) Animal energetics, Vol 2: Bivalvia through Reptilia. In: Pandian TJ, Vernberg FJ (eds) Bivalvia. Academic Press, New York, NY, p 1â88 Harvey BP, Dwynn-Jones D, Moore PJ (2013) Meta-analysis reveals complex marine biological responses to the inter-active effects of ocean acidification and warming. Ecol Evol 3: 1016â1030 Hiebenthal C, Philipp EER, Eisenhauer A, Wahl M (2013) Effects of seawater pCO2 and temperature on shell growth, shell stability, condition and cellular stress of western Baltic Sea Mytilus edulis (L.) and Arctica is - landica (L.). Mar Biol 160: 2073â2087 Ibarrola I, Arambalza U, Navarro JM, Urrutia MB, Navarro E (2012) Allometric relationships in feeding and diges-tion in the Chilean mytilids Mytilus chilensis (HupĂ©), Choromytilus chorus (Molina) and Aulacomya ater (Mo - lina): a comparative study. J Exp Mar Biol Ecol 426-427: 18â27 Lagos NA, BenĂtez S, Duarte C, Lardies MA and others (2016) Effects of temperature and ocean acidification on shell characteristics of Argopecten purpuratus: implica-tions for scallop aquaculture in an upwelling-influenced area. Aquacult Environ Interact 8: 357â370 Lardies MA, Arias MB, Poupin MJ, ManrĂquez PH and oth-ers (2014) Differential response to ocean acidification in physiological traits of Concholepas concholepas popula-tions. J Sea Res 90: 127â134 Lardies MA, BenĂtez S, Osores S, Vargas CA, Duarte C, Lohrmann KB, Lagos NA (2017) Physiological and histo - pathological impacts of increased carbon dioxide and temperature on the scallops Argopecten purpuratus cultured under upwelling influences in northern Chile. Aquaculture 479: 455â466 Lemasson AJ, Fletcher S, Hall-Spencer JM, Knights AM (2017) Linking the biological impacts of ocean acidifica-tion on oysters to changes in ecosystem services: a review. J Exp Mar Biol Ecol 492: 49â62 Mackenzie CL, Ormondroyd GA, Curling SF, Ball RJ, Whitely NM, Malham SK (2014) Ocean warming, more than acidification, reduces shell strength in a commercial shellfish species during food limitation. PLOS ONE 9: e86764 McElhany P (2017) CO2 sensitivity experiments are not suf-ficient to show an effect of ocean acidification. ICES J Mar Sci 74: 926â928 Mehrbach C, Culberson CH, Hawley JE, Pytkowicz RM (1973) Measurement of the apparent dissociation con-stants of carbonic acid in seawater at atmospheric pres-sure. Limnol Oceanogr 18: 897â907 Melzner F, Thomsen J, Koeve W, Oschlies A and others (2013) Future ocean acidification will be amplified by hypoxia in coastal habitats. Mar Biol 160: 1875â1888 Michaelidis B, Ouzounis C, Paleras A, Pörtner HO (2005) Effects of long-term moderate hypercapnia on acidâbase balance and growth rate in marine mussels Mytilus gal-loprovincialis. Mar Ecol Prog Ser 293: 109â118 Miller AW, Reynolds AC, Sobrino C, Riedel GF (2009) Shell-fish face uncertain future in high CO2 world: influence of acidification on oyster larvae calcification and growth in estuaries. PLOS ONE 4: e5661 Navarro JM (1988) The effects of salinity on the physio - logical ecology of Choromytilus chorus (Molina, 1782) (Bivalvia: Mytilidae). J Exp Mar Biol Ecol 122: 19â33 Navarro JM, Torres R, Acuña K, Duarte C and others (2013) Impact of medium-term exposure to elevated pCO2 lev-els on the physiological energetics of the mussel Mytilus chilensis. Chemosphere 90: 1242â1248 Navarro JM, Duarte C, ManrĂquez PH, Lardies MA and oth-ers (2016) Ocean warming and elevated carbon dioxide: multiple stressor impacts on juvenile mussels from south-ern Chile. ICES J Mar Sci 73: 764â771 Nienhuis S, Palmer AR, Harley CD (2010) Elevated CO2 affects shell dissolution rate but not calcification rate in a marine snail. Proc R Soc B 277: 2553â2558 Orr JC, Fabry VJ, Aumont O, Bopp L and others (2005) Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437: 681â686 Osores SJ, Lagos NA, San Martin V, ManrĂquez PH and others (2017) Plasticity and inter-population variability in physiological and life-history traits of the mussel Mytilus chilensis: a reciprocal transplant experiment. J Exp Mar Biol Ecol 490: 1â12 Palmer AR (1982) Growth in marine gastropods: a non-destructive technique for independently measuring shell and body weight. Malacologia 23: 63â73 Parker LM, Ross PM, OâConnor WA, Borysko L, Raftos DA, Pörtner HO (2012) Adult exposure influences offspring response to ocean acidification in oysters. Glob Change Biol 18: 82â92 Pierrot D, Lewis E, Wallace DWR (2006) MS Excel program developed for CO2 system calculations. ORNL/CDIAC-105a. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, TN Ramajo L, Marba N, Prado L, Peron S and others (2016) Bio-mineralization changes with food supply confer juvenile scallops (Argopecten purpuratus) resistance to ocean acidification. Glob Change Biol 22: 2025â2037 Range P, ChĂcharo MA, Ben-Hamadou R, PilĂł D and others (2014) Impacts of CO2-induced seawater acidification on coastal Mediterranean bivalves and interactions with other climatic stressors. Reg Environ Change 14(Suppl 1): 19â30 Sabine C, Feely RA, Gruber N, Key RM and others (2004) The oceanic sink of anthropogenic CO2. Science 305: 367â371 SERNAPESCA (Servicio Nacional de Pesca y Acuicultura) (2014) Anuarios estadĂsticos del Servicio Nacional de Pesca y Acuicultura. www.sernapesca.cl SolĂłrzano L (1969) Determination of ammonia in natural waters by the phenolhypochlorite method. Limnol Oce - anogr 14: 799â801 Thomsen J, Melzner F (2010) Moderate seawater acidifica-tion does not elicit long-term metabolic depression in the blue mussel Mytilus edulis. Mar Biol 157: 2667â2676 Thomsen J, Casties I, Pansch C, Körtzinger A, Melzner F (2013) Food availability outweighs ocean acidification effects in juvenile Mytilus edulis: laboratory and field experiments. Glob Change Biol 19: 1017â1027 Thomsen J, Stapp LS, Haynert K, Schade H, Danelli M, Lannig G, Melzner F (2017) Naturally acidified habitat selects for ocean acidification-tolerant mussels. Sci Adv 3: e1602411 Toro B, Navarro JM, Palma-Fleming H (2003) Relationship between bioenergetics responses and organic pollutants in the giant mussel, Choromytilus chorus (Mollusca: Mytilidae). Aquat Toxicol 63: 257â269 Torres R, Pantoja S, Harada N, GonzĂĄlez HE, Daneri G, Frangopulos M, Fukasawa M (2011) Air-sea CO2 fluxes along the coast of Chile: from CO2 outgassing in central northern upwelling waters to CO2 uptake in southern Patagonian fjords. J Geophys Res 116: C09006 Torres R, Manriquez PH, Duarte C, Navarro JM, Lagos NA, Vargas CA, Lardies MA (2013) Evaluation of a semi - automatic system for long-term seawater carbonate chemistry manipulation. Rev Chil Hist Nat 86: 443â451 Vargas CA, Aguilera V, MartĂn V, ManrĂquez P and others (2015) CO2-driven ocean acidification disrupts the filter feeding behavior in Chilean gastropod and bivalve spe-cies from different geographic localities. Estuaries Coasts 38: 1163â1177 Vargas CA, Lagos NA, Lardies MA, Duarte C and others (2017) Species-specific responses to ocean acidification should account for local adaptation and adaptive plasti-city. Nature Ecol Evol 1: 0084 Vargas CA, Cuevas LA, Silva N, Gonzalez HE, Pol-Holz D, Narvaez DA (2018) Influence of glacier melting and river discharges on the nutrient distribution and DIC recycling in the southern Chilean Patagonia. J Geophys Res Bio-geosci 123: 256â270 Velasco LA, Navarro JM (2003) Energetic balance of infau-nal (Mulinia edulis King, 1831) and epifaunal (Mytilus chilensis HupĂ©, 1854) bivalves in response to wide varia-tions in concentration and quality of seston. J Exp Mar Biol Ecol 296: 79â92 Vihtakari M, Hendriks IE, Holding J, Renaud PE, Duarte CM, Havenhand JN (2013) Effects of ocean acidification and warming on sperm activity and early life stages of the Mediterranean mussel (Mytilus galloprovincialis). Water 5: 1890â1915 Wang Y, Li L, Hu M, Lu W (2015) Physiological energetic of the thick shell mussel Mytilus coruscus exposed to sea-water acidification and thermal stress. Sci Total Environ 514: 261â272 White MM, McCorkle DC, Mullineaux LS, Cohen AL (2013)Benthic habitats such as intertidal areas, sandy or rocky shores, upwelling zones, and estuaries are characterized by variable environmental conditions. This high variability of environmental stressors such as temperature, salinity, and pH/pCO 2 levels have been shown to impose restrictions on organismal performance. The giant mussel Choromytilus chorus forms intertidal and subtidal mussel beds in estuarine zones associated with fjords occurring in southern Chile and is an important aquacultural resource in Patagonia. In this study, we estimated the sensitivity of physiological traits and energy balance of C. chorus juveniles exposed to 3 pCO 2 treatments (500, 750, and 1200 ÎŒatm) for 30 d. Results showed that in acidified, high pCO 2 conditions, C. chorus juveniles had increased metabolic rates; however, other physiological traits (clearance and ingestion rates, ammonia excretion, absorption efficiency, growth rate, biomass production, net calcification, and dissolution rates) were not affected. These results suggest that when subjected to acidification, the adaptive response of C. chorus triggers tradeoffs among physiological traits that favor sustained feeding and growth in order to combat increased metabolic stress. As has been reported for other marine organisms, chronic exposure to variable pH/pCO 2 in their native habitats, such as estuarine zones, could explain the differential acclimatization capacity of giant mussels to cope with the increase in pCO 2 . Additionally, the fact that the mussels did not suffer from mortality indicates that increased pCO 2 levels may have chronic, but not lethal, effects on this species under these experimental conditions. © The authors 2017.https://www.int-res.com/abstracts/aei/v10/p267-278
First detection of CF+ towards a high-mass protostar
We report the first detection of the J = 1 - 0 (102.6 GHz) rotational lines
of CF+ (fluoromethylidynium ion) towards CygX-N63, a young and massive
protostar of the Cygnus X region. This detection occurred as part of an
unbiased spectral survey of this object in the 0.8-3 mm range, performed with
the IRAM 30m telescope. The data were analyzed using a local thermodynamical
equilibrium model (LTE model) and a population diagram in order to derive the
column density. The line velocity (-4 km s-1) and line width (1.6 km s-1)
indicate an origin from the collapsing envelope of the protostar.
We obtain a CF+ column density of 4.10e11 cm-2. The CF+ ion is thought to be
a good tracer for C+ and assuming a ratio of 10e-6 for CF+/C+, we derive a
total number of C+ of 1.2x10e53 within the beam. There is no evidence of carbon
ionization caused by an exterior source of UV photons suggesting that the
protostar itself is the source of ionization. Ionization from the protostellar
photosphere is not efficient enough. In contrast, X-ray ionization from the
accretion shock(s) and UV ionization from outflow shocks could provide a large
enough ionizing power to explain our CF+ detection.
Surprisingly, CF+ has been detected towards a cold, massive protostar with no
sign of an external photon dissociation region (PDR), which means that the only
possibility is the existence of a significant inner source of C+. This is an
important result that opens interesting perspectives to study the early
development of ionized regions and to approach the issue of the evolution of
the inner regions of collapsing envelopes of massive protostars. The existence
of high energy radiations early in the evolution of massive protostars also has
important implications for chemical evolution of dense collapsing gas and could
trigger peculiar chemistry and early formation of a hot core.Comment: 6 page
A unification in the theory of linearization of second order nonlinear ordinary differential equations
In this letter, we introduce a new generalized linearizing transformation
(GLT) for second order nonlinear ordinary differential equations (SNODEs). The
well known invertible point (IPT) and non-point transformations (NPT) can be
derived as sub-cases of the GLT. A wider class of nonlinear ODEs that cannot be
linearized through NPT and IPT can be linearized by this GLT. We also
illustrate how to construct GLTs and to identify the form of the linearizable
equations and propose a procedure to derive the general solution from this GLT
for the SNODEs. We demonstrate the theory with two examples which are of
contemporary interest.Comment: 8 page
Axial gravity, massless fermions and trace anomalies
This article deals with two main topics. One is odd parity trace anomalies in
Weyl fermion theories in a 4d curved background, the second is the introduction
of axial gravity. The motivation for reconsidering the former is to clarify the
theoretical background underlying the approach and complete the calculation of
the anomaly. The reference is in particular to the difference between Weyl and
massless Majorana fermions and to the possible contributions from tadpole and
seagull terms in the Feynman diagram approach. A first, basic, result of this
paper is that a more thorough treatment, taking account of such additional
terms { and using dimensional regularization}, confirms the earlier result. The
introduction of an axial symmetric tensor besides the usual gravitational
metric is instrumental to a different derivation of the same result using Dirac
fermions, which are coupled not only to the usual metric but also to the
additional axial tensor. The action of Majorana and Weyl fermions can be
obtained in two different limits of such a general configuration. The results
obtained in this way confirm the previously obtained ones.Comment: 55 pages, comments added in section 2 and 5. Sections 6.4, 6.6, 7,
7.1, 7.2 and Appendices 5.3, 5.5 partially modifie
Bayesian inference with an adaptive proposal density for GARCH models
We perform the Bayesian inference of a GARCH model by the Metropolis-Hastings
algorithm with an adaptive proposal density. The adaptive proposal density is
assumed to be the Student's t-distribution and the distribution parameters are
evaluated by using the data sampled during the simulation. We apply the method
for the QGARCH model which is one of asymmetric GARCH models and make empirical
studies for for Nikkei 225, DAX and Hang indexes. We find that autocorrelation
times from our method are very small, thus the method is very efficient for
generating uncorrelated Monte Carlo data. The results from the QGARCH model
show that all the three indexes show the leverage effect, i.e. the volatility
is high after negative observations
Beyond onboard sensors in robotic swarms: Local collective sensing through situated communication
The constituent robots in swarm robotics systems are typically equipped with relatively simple, onboard sensors of limited quality and range. When robots have the capacity to communicate with one another, communication has so far been exclusively used for coordination. In this paper, we present a novel approach in which
local, situated communication is leveraged to overcome the sensory limitations of the individual robots. In
our approach, robots share sensory inputs with neighboring robots, thereby effectively extending each otherâs
sensory capabilities. We evaluate our approach in a series of experiments in which we evolve controllers for
robots to capture mobile preys. We compare the performance of (i) swarms that use our approach, (ii) swarms
in which robots use only their limited onboard sensors, and (iii) swarms in which robots are equipped with
ideal sensors that provide extended sensory capabilities without the need for communication. Our results show
that swarms in which local communication is used to extend the sensory capabilities of the individual robots
outperform swarms in which only onboard sensors are used. Our results also show that in certain experimental
configurations, the performance of swarms using our approach is close to the performance of swarms with
ideal sensors.info:eu-repo/semantics/acceptedVersio
On a generalised model for time-dependent variance with long-term memory
The ARCH process (R. F. Engle, 1982) constitutes a paradigmatic generator of
stochastic time series with time-dependent variance like it appears on a wide
broad of systems besides economics in which ARCH was born. Although the ARCH
process captures the so-called "volatility clustering" and the asymptotic
power-law probability density distribution of the random variable, it is not
capable to reproduce further statistical properties of many of these time
series such as: the strong persistence of the instantaneous variance
characterised by large values of the Hurst exponent (H > 0.8), and asymptotic
power-law decay of the absolute values self-correlation function. By means of
considering an effective return obtained from a correlation of past returns
that has a q-exponential form we are able to fix the limitations of the
original model. Moreover, this improvement can be obtained through the correct
choice of a sole additional parameter, . The assessment of its validity
and usefulness is made by mimicking daily fluctuations of SP500 financial
index.Comment: 6 pages, 4 figure
Development and validation of a new standard area diagram set to estimate severity of soybean rust.
TĂtulo em portuguĂȘs: Desenvolvimento e validação de uma nova escala diagramĂĄtica para estimar severidade de ferrugem asiĂĄtica da soja
Giardia sp. and Cryptosporidium sp. in Iberian Wolf
ÎÎÎ ÎÎÎ΀ÎÎÎ΀ÎÎ Î ÎÎĄÎÎÎΚÎA subsample consisting of fifty fecal samples from wild Iberian Wolf (Canis lupus signatus), from the northwest of Spain were collected in the field. The samples were analyzed for cysts of Giardia sp. and oocysts of Cryptosporidium sp. using a direct immunofluorescence antibody test (IFA). Giardia sp. and Cryptosporidium sp. were found in 20.0 % of the samples examined. Simple infections were more frequent (90.0 %) with seven (14.0 %) positive for Giardia sp. and two (4.0 %) positive for Cryptosporidium sp. To the authorsâ knowledge, this is the first report of occurrence of Cryptosporidium sp. in Iberian Wolf
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