Dynamic regimes of hydrodynamically coupled self-propelling particles

We analyze the collective dynamics of self-propelling particles (spps) which move at small Reynolds numbers including the hydrodynamic coupling to the suspending solvent through numerical simulations. The velocity distribution functions show marked deviations from Gaussian behavior at short times, and the mean-square displacement at long times shows a transition from diffusive to ballistic motion for appropriate driving mechanism at low concentrations. We discuss the structures the spps form at long times and how they correlate to their dynamic behavior.Comment: 7 pages, 4 figure

Decision making under uncertainty in environmental projects using mathematical simulation modeling

The final publication is available at Springer via http://dx.doi.org/10.1007/s12665-016-6135-yIn decision-making processes, reliability and risk aversion play a decisive role. The aim of this study is to perform an uncertainty assessment of the effects of future scenarios of sustainable groundwater pumping strategies on the quantitative and chemical status of an aquifer. The good status of the aquifer is defined according to the terms established by the EU Water Framework Directive (WFD). A decision support systems (DSS) is presented, which makes use of a stochastic inverse model (GC method) and geostatistical approaches to calibrate equally likely realizations of hydraulic conductivity (K) fields for a particular case study. These K fields are conditional to available field data, including hard and soft information. Then, different future scenarios of groundwater pumping strategies are generated, based on historical information and WFD standards, and simulated for each one of the equally likely K fields. The future scenarios lead to different environmental impacts and levels of socioeconomic development of the region and, hence, to a different degree of acceptance among stakeholders. We have identified the different stakeholders implied in the decision-making process, the objectives pursued and the alternative actions that should be considered by stakeholders in a public participation project (PPP). The MonteCarlo simulation provides a highly effective way for uncertainty assessment and allows presenting the results in a simple and understandable way even for non-experts stakeholders. The methodology has been successfully applied to a real case study and lays the foundations to performa PPP and stakeholders' involvement in a decisionmaking process as required by the WFD. The results of the methodology can help the decision-making process to come up with the best policies and regulations for a groundwater system under uncertainty in groundwater parameters and management strategies and involving stakeholders with conflicting interests.Llopis Albert, C.; Palacios Marqués, D.; Merigó -Lindahl, JM. (2016). Decision making under uncertainty in environmental projects using mathematical simulation modeling. Environmental Earth Sciences. 75(19):1-11. doi:10.1007/s12665-016-6135-yS1117519Arhonditsis GB, Perhar G, Zhang W, Massos E, Shi M, Das A (2008) Addressing equifinality and uncertainty in eutrophication models. Water Resour Res 44:W01420. doi: 10.1029/2007WR005862Capilla JE, Llopis-Albert C (2009) Gradual conditioning of non-gaussian transmissivity fields to flow and mass transport data. J Hydrol 371:66–74. doi: 10.1016/j.jhydrol.2009.03.015CHJ (Júcar Water Agency) (2016) Júcar river basin authority. http://www.chj.es/CHS (Segura Water Agency) (2016) Segura river basin authority. http://www.chsegura.es/Custodio E (2002) Aquifer overexploitation: what does it mean? Hydrogeol J 10:254–277EC (2000). Directive 2000/60/EC of the European Parliament and of the Council of October 23 2000, establishing a framework for community action in the field of water policy. Official Journal of the European Communities L327/1eL327/72. 22.12.2000EC (2006) Directive 2006/118/EC of the European Parliament and of the Council of 12 December 2006 on the protection of groundwater against pollution and deteriorationGómez-Hernández JJ, Srivastava RM (1990) ISIM3D: an ANSI-C three dimensional multiple indicator conditional simulation program. Comput Geosci 16(4):395–440Harbaugh AW, Banta ER, Hill MC and McDonald MG (2000) MODFLOW- 2000, The US geological survey modular groundwater model-user guide to modularization concepts and the groundwater flow process. US Geol. Surv. Open-File Rep 00–92, 12Hu LY (2000) Gradual deformation and iterative calibration of Gaussian related stochastic models. Math Geol 32(1):87–108Jagelke J, Barthel R (2005) Conceptualization and implementation of a regional groundwater model for the Neckar catchment in the framework of an integrated regional model. Adv Geosci 5:105–111Llopis-Albert C (2008) Stochastic inverse modeling conditional to flow, mass transport and secondary information. Universitat Politècnica de València, València. ISBN 978-84-691-9796-7Llopis-Albert C, Capilla JE (2009a) Gradual conditioning of non-gaussian transmissivity fields to flow and mass transport data. Demonstration on a synthetic aquifer. J Hydrol 371:53–55. doi: 10.1016/j.jhydrol.2009.03.014Llopis-Albert C, Capilla JE (2009b) Gradual conditioning of non-gaussian transmissivity fields to flow and mass transport data. Application to the macrodispersion experiment (MADE-2) site, on Columbus air force base in Mississippi (USA). J Hydrol 371:75–84. doi: 10.1016/j.jhydrol.2009.03.016Llopis-Albert C, Capilla JE (2010a) Stochastic simulation of non-gaussian 3D conductivity fields in a fractured medium with multiple statistical populations: a case study. J Hydrol Eng 15(7):554–566. doi: 10.1061/(ASCE)HE.1943-5584.0000214Llopis-Albert C, Capilla JE (2010b) Stochastic inverse modeling of hydraulic conductivity fields taking into account independent stochastic structures: a 3D case study. J Hydrol 391:277–288. doi: 10.1016/j.jhydrol.2010.07.028Llopis-Albert C, Pulido-Velazquez D (2014) Discussion about the validity of sharp-interface models to deal with seawater intrusion in coastal aquifers. Hydrol Process 28(10):3642–3654Llopis-Albert C, Pulido-Velazquez D (2015) Using MODFLOW code to approach transient hydraulic head with a sharp-interface solution. Hydrol Process 29(8):2052–2064. doi: 10.1002/hyp.10354Llopis-Albert C, Palacios-Marqués D, Merigó JM (2014) A coupled stochastic inverse-management framework for dealing with nonpoint agriculture pollution under groundwater parameter uncertainty. J Hydrol 511:10–16. doi: 10.1016/j.jhydrol.2014.01.021Llopis-Albert C, Merigó JM, Palacios-Marqués D (2015) Structure adaptation in stochastic inverse methods for integrating information. Water Resour Manage 29(1):95–107. doi: 10.1007/s11269-014-0829-2Llopis-Albert C, Merigó JM, Xu Y (2016) A coupled stochastic inverse/sharp interface seawater intrusion approach for coastal aquifers under groundwater parameter uncertainty. J Hydrol 540:774–783. doi: 10.1016/j.jhydrol.2016.06.065McDonald MG and Harbaugh AW (1988) A modular three-dimensional finite-difference groundwater flow model. US geological survey technical manual of water resources investigation, Book 6, US geological survey, Reston, Virginia, 586Molina JL, Pulido-Velazquez M, Llopis-Albert C, Peña-Haro S (2013) Stochastic hydro-economic model for groundwater quality management using Bayesian networks. Water Sci Technol 67(3):579–586. doi: 10.2166/wst.2012.598Peña-Haro S, Llopis-Albert C, Pulido-Velazquez M (2010) Fertilizer standards for controlling groundwater nitrate pollution from agriculture: El Salobral-Los Llanos case study, Spain. J Hydrol 392:174–187. doi: 10.1016/j.jhydrol.2010.08.006Peña-Haro S, Pulido-Velazquez M, Llopis-Albert C (2011) Stochastic hydro-economic modeling for optimal management of agricultural groundwater nitrate pollution under hydraulic conductivity uncertainty. Environ Model Softw 26(8):999–1008. doi: 10.1016/j.envsoft.2011.02.010Pulido-Velazquez D, Llopis-Albert C, Peña-Haro S, Pulido-Velazquez M (2011) Efficient conceptual model for simulating the effect of aquifer heterogeneity on natural groundwater discharge to rivers. Adv Water Resour 34(11):1377–1389. doi: 10.1016/j.advwatres.2011.07.010Reichert P, Borsuk M, Hostmann M, Schweizer S, Spörri C, Tockner K, Truffer B (2005) Concepts of decision support for river rehabilitation. Environ Model Softw 22:188–201Wright SAL, Fritsch O (2011) Operationalising active involvement in the EU water framework directive: why, when and how? Ecol Econ 70(12):2268–2274Zhou H, Gómez-Hernández JJ, Li L (2014) Inverse methods in hydrogeology: evolution and recent trends. Adv Water Resour 63:22–37. doi: 10.1016/j.advwatres.2013.10.01

Q fever: a new ocular manifestation

Q Fever is a zoonosis caused by Coxiella burnetii. Ocular manifestations are rare in this infection. We describe the case of a man complaining of an intense retro-orbital headache, fever, arthralgia, and bilateral loss of vision, who showed an anterior uveitis accompanied by exudative bilateral inferior retinal detachment and optic disk edema. At the beginning, a Vogt–Koyanagi–Harada (VKH) syndrome was suspected, but the patient was diagnosed with Q fever and treatment with doxycycline was initiated, with complete resolution after 2 weeks. We wondered if Q fever could unleash VKH syndrome or simulate a VKH syndrome by a similar immunological process

Toward Interdisciplinary Synergies in Molecular Communications: Perspectives from Synthetic Biology, Nanotechnology, Communications Engineering and Philosophy of Science

Within many chemical and biological systems, both synthetic and natural, communication via chemical messengers is widely viewed as a key feature. Often known as molecular communication, such communication has been a concern in the fields of synthetic biologists, nanotechnologists, communications engineers, and philosophers of science. However, interactions between these fields are currently limited. Nevertheless, the fact that the same basic phenomenon is studied by all of these fields raises the question of whether there are unexploited interdisciplinary synergies. In this paper, we summarize the perspectives of each field on molecular communications, highlight potential synergies, discuss ongoing challenges to exploit these synergies, and present future perspectives for interdisciplinary efforts in this area

C60/NiFe combination as a promising platform for molecular spintronics

Spintronics based on ferromagnetic metals and organic semiconductors has attracted great interest in recent years. Molecular-based spintronic devices, such as magnetic tunnel junctions, have been demonstrated with performances competing with those of conventional inorganic devices. Still, there is huge margin for improvement, as many details about the injection of spin-polarized electrons into the molecular layer remain not completely understood. In order to achieve better understanding and control of the physical mechanisms, it is necessary to explore various combinations of ferromagnetic metals and organic semiconductors. In this letter, we study the properties of the combination between the ferromagnetic metal NiFe (commonly known as Permalloy or Py) and the molecular system C60. We produced C60/Py bilayers and characterized them structurally, electrically and magnetically. The C 60 films grow smoothly on both Py and SiO2 substrates, and we estimate that a 5-nm-thick C60 film covers completely the surface underneath without leaving pinholes and can be therefore used in a vertical device, as confirmed by electrical characterization. Furthermore, the C 60 film is robust against the deposition of the top metal electrode, being the intermixing layer of only 1-2 nm at the C60/Py interface. Finally, we show that the magnetic properties of Py are not affected by the deposition sequence, and that a 5-nm-thick Py layer on top of a C60 layer keeps its magnetic properties intact. These results show that the combination between Py and C60 provides a robust template platform for the development of molecular spintronics, and can be used later on for more sophisticated investigations, such as the role of the interfaces in the spin injection.Fil: Gobbi, M.. No especifíca;Fil: Pascual, A.. No especifíca;Fil: Golmar, Federico. Instituto Nacional de Tecnología Industrial; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Llopis, R.. No especifíca;Fil: Vavassori, P.. No especifíca;Fil: Casanova, F.. No especifíca;Fil: Hueso, L. E.. No especifíca

Surface plasmon resonance of capped Au nanoparticles

In this Rapid Communication we show the relationship between surface plasmon resonance damping and the intensity of surface bonding for capped Au nanoparticles, (NPs). Up to now the influence of capping has been included as a phenomenological modification of the scattering constant. It is indicated here that the effective NP size is the parameter mainly affected by surface bonding. Experimental results in different Au-thiol NPs are shown to be in excellent agreement with the expression we propose for damping. Moreover, according to our model the resonance profile gives a deep insight of the interface bonding strength

Effective Viscosity of Dilute Bacterial Suspensions: A Two-Dimensional Model

Suspensions of self-propelled particles are studied in the framework of two-dimensional (2D) Stokesean hydrodynamics. A formula is obtained for the effective viscosity of such suspensions in the limit of small concentrations. This formula includes the two terms that are found in the 2D version of Einstein's classical result for passive suspensions. To this, the main result of the paper is added, an additional term due to self-propulsion which depends on the physical and geometric properties of the active suspension. This term explains the experimental observation of a decrease in effective viscosity in active suspensions.Comment: 15 pages, 3 figures, submitted to Physical Biolog

Intravitreal bevacizumab (Avastin) for choroidal metastasis secondary to breast carcinoma: short-term follow-up

Uveal metastases are the most common intraocular malignancy. The most common primary sites of cancer are from the breast (47%) and lung (21%).1 The treatment for choroidal metastasis depends on many factors including location, multiplicity, and activity of each tumour.1 Bevacizumab (Avastins) is a full-length humanized murine monoclonal antibody against the VEGF molecule, and inhibits angiogenesis and tumour growth.2 In this report, we describe the effect of a single intravitreal injection of bevacizumab (4 mg) in a patient with choroidal metastasis secondary to breast cancerMedicin

The reactivity of cyclopropyl cyanide in titan's atmosphere: a possible pre-biotic mechanism

Cyclopropyl cyanide and other simple nitriles detected in Titan's atmosphere could be precursors leading to the formation of organic macromolecules in the atmosphere of Saturn's largest satellite. Proposing a thermodynamically possible mechanism that explains their formation and supports experimental results represents a difficult challenge. Experiments done in the Atomic and Molecular Physics Laboratory at the University of Trento (AMPL) have studied the ion-molecule reaction between cyclopropyl cyanide and its protonated form, with reaction products being characterized by mass spectrometry. In addition to the expected ion-molecule adduct stabilized by non-covalent long-range interactions, in this work we prove that another distinct species having the same mass to charge ratio (m/z) of 135 is also produced. Moreover, from a previous study of the neutral cyclopropyl cyanide potential energy surface (PES) which shows a partial biradical character it has been possible to characterize the formation through the bimolecular reaction of a new covalent cyclic organic molecule. Calculations have been carried out at the ab initio Møller-Plesset (MP2) level of theory, ensuring the connectivity of the stationary points by using the intrinsic reaction coordinate (IRC) procedure. In order to characterize the reaction transition state, multireference calculations were done using a complete active space involving six electrons and six molecular orbitals [CAS (6 e, 6 m.o.)]. This study opens the possibility of exploring the formation of new organic molecules by gaseous phase ion-molecule interaction schemes, with such molecules having relevance in interstellar space and in astrobiology (and may be involved in prebiotic molecular evolution)