2,147 research outputs found
Embryo Manipulation Techniques in the Rabbit
Rabbits are both productive and classic laboratory animals. Some particularities of female reproductive physiology make the rabbit an extraordinary model for the study of embryology and assisted reproductive techniques. For instance, as the ovulation is induced, the embryo development can be known with accuracy. Embryos are surrounded by a mucin coat which is crucial to prevent embryo mortality. Besides, the anatomy of the uterus does not allow embryo transmigration between both uterine horns, and so it is possible to test different reproductive techniques. Knowledge on early embryo development, and on influencing factors, has allowed to develop new insights into embryo manipulation, such as recovery, transfer, cryopreservation, in vitro fertilisation, cloning, or transgenesis. Also the rabbit may be used as a model for human reproductive health, because rabbit embryo and feto-placental development are similar to the human. This chapter reviews the aspects of the reproductive physiology in the female rabbit and discusses some embryo manipulation techniques available in the species
Fiber Optic Acoustic Sensing to Understand and Affect the Rhythm of the Cities: Proof-of-Concept to Create Data-Driven Urban Mobility Models
In the framework of massive sensing and smart sustainable cities, this work presents an
urban distributed acoustic sensing testbed in the vicinity of the School of Technology and Telecommunication
Engineering of the University of Granada, Spain. After positioning the sensing technology
and the state of the art of similar existing approaches, the results of the monitoring experiment are
described. Details of the sensing scenario, basic types of events automatically distinguishable, initial
noise removal actions and frequency and signal complexity analysis are provided. The experiment,
used as a proof-of-concept, shows the enormous potential of the sensing technology to generate
data-driven urban mobility models. In order to support this fact, examples of preliminary density
of traffic analysis and average speed calculation for buses, cars and pedestrians in the testbed’s
neighborhood are exposed, together with the accidental presence of a local earthquake. Challenges,
benefits and future research directions of this sensing technology are pointed out.B-TIC-542-UGR20 funded by “Consejería de Universidad,
Investigación e Innovacción de la Junta de AndalucíaERDF A way of making
Europ
Islamist and communists: A history of Arab convergenze parallele
This is an Accepted Manuscript of a book chapter published by Routledge/CRC
Press in Communist parties in the Middle East: 100 years of history on 2019,
available online: https://doi.org/10.4324/9780367134464This article is part of the ongoing I+D+i Spanish project ALAM (FFI2014–54667-R
Forcing Arguments in Infinite RamseyTheory
This is a contribution to combinatorial set theory, specifically to infinite Ramsey Theory, which deals with partitions of infinite sets. The basic pigeon hole principle states that for every partition of the set of all natural numbers in finitely many classes there is an infinite set of natural numbers that is included in some one class. Ramsey’s Theorem, which can be seen as a generalization of this simple result, is about partitions of the set [N]k of all k-element sets of natural numbers. It states that for every k ≥ 1 and every partition of [N]k into finitely many classes, there is an infinite subset M of N such that all k-element subsets of M
belong to some same class. Such a set is said to be homogeneous for the partition. In Ramsey’s own formulation (Ramsey, [8], p.264), the theorem reads as follows.
Theorem (Ramsey). Let Γ be an infinite class, and μ and r positive numbers; and let all those sub-classes of Γ which have exactly r numbers, or, as we may say, let all r−combinations of the members of Γ be divided in any manner into μ mutually exclusive classes Ci (i = 1, 2, . . . , μ), so that every r−combination is a member of one and only one Ci; then assuming the axiom of selections, Γ must contain an infinite sub-class △ such that all the r−combinations of the members of △ belong to the same Ci.
In [5], Neil Hindman proved a Ramsey-like result that was conjectured by Graham and Rotschild in [3]. Hindman’s Theorem asserts that if the set of all natural numbers is divided into two classes, one of the classes contains an infinite set such that all finite sums of distinct members of the set remain in the same class. Hindman’s original proof was greatly simplified, though the same basic ideas were used, by James Baumgartner in [1].
We will give new proofs of these two theorems which rely on forcing arguments. After this, we will be concerned with the particular partial orders used in each case, with the aim of studying its basic properties and its relations to other similar forcing notions. The partial order used to get Ramsey’s Theorem will be seen to be equivalent to Mathias forcing. The analysis of the partial order arising in the proof of Hindmans Theorem, which we denote by PFIN, will be object of the last chapter of the thesis.
A summary of our work follows.
In the first chapter we give some basic definitions and state several known theorems that we will need. We explain the set theoretic notation used and we describe some forcing notions that will be useful in the sequel. Our notation is generally standard, and when it is not it will be sufficiently explained. This work is meant to be self-contained. Thus, although most of the theorems recorded in this first, preliminary chapter, will be stated without proof, it will be duly indicated where a proof can be found.
Chapter 2 is devoted to a proof of Ramsey’s Theorem in which forcing is used to produce a homogeneous set for the relevant partition. The partial order involved is isomorphic to Mathias forcing.
In Chapter 3 we modify Baumgartner’s proof of Hindman’s Theorem to define a partial order, denoted by PC , from which we get by a forcing argument a suitable homogeneous set. Here C is an infinite set of finite subsets of N, and PC adds an infinite block sequence of finite subsets of natural numbers with the property that all finite unions of its elements belong to C. Our proof follows closely Baumgartner’s.
The partial order PC is similar both to the one due to Matet in [6] and to Mathias forcing. This prompts the question whether it is equivalent to one of them or to none, which can only be solved by studying PC , which we do in chapter 4.
In chapter 4 we first show that the forcing notion PC is equivalent to a more manageable partial order, which we denote by PFIN. From a PFIN- generic filter an infinite block sequence can be defined, from which, in turn, the generic filter can be reconstructed, roughly as a Mathias generic filter can be reconstructed from a Mathias real.
In section 4.1 we prove that PFIN is not equivalent to Matet forcing. This we do by showing that PFIN adds a dominating real, thus also a splitting real (see [4]). But Blass proved that Matet forcing preserves p-point ultrafilters in [2], from which follows that Matet forcing does not add splitting reals. Still in section 4.1 we prove that PFIN adds a Mathias real by using Mathias characterization of a Mathias real in [7] according to which x ⊆ ω is a Mathias real over V iff x diagonalizes every maximal almost disjoint family in V . In fact, we prove that if D = (Di)i∈ω is the generic block sequence of finite sets of natural numbers added by forcing with PFIN, then both {minDi : i ∈ ω} and {maxDi : i ∈ ω} are Mathias reals.
In section 4.2 we prove that PFIN is equivalent to a two-step iteration of a σ-closed and a σ-centered forcing notions.
In section 4.3 we prove that PFIN satisfies Axiom A and in section 4.4 that, as Mathias forcing, it has the pure decision property. In section 4.5 we prove that PFIN does not add Cohen reals. So far, all the properties we have found of PFIN are also shared by Mathias forcing. The question remains, then, whether PFIN is equivalent to Mathias forcing. This we solve by first showing in section 5.1 that PFIN adds a Matet real and then, in section 5.2, that Mathias forcing does not add a Matet real, thus concluding that PFIN and Mathias forcing are not equivalent forcing notions.
In the last, 5.3, section we explore another forcing notion, denoted by M2, which was introduced by Shelah in [9]. It is a kind of “product” of two copies of Mathias forcing, which we relate to denoted by M2.
Bibliography
[1] J.E. Baumgartner. A short proof of Hindmanʼs theorem. Journal of Combinatorial Theory, 17:384–386, 1974.
[2] A. Blass. Applications of superperfect forcing and its relatives. In Set theory and its applications. Lecture notes in Mathematics. Springer, Berlin., 1989.
[3] R.L. Graham and B. L. Rothschild. Ramseyʼs theorem for n-parameter sets. Transaction American Mathematical Society, 159:257–292, 1971.
[4] L. Halbeisen. A playful approach to Silver and Mathias forcing. Studies in Logic (London), 11:123142, 2007. [5] N. Hindman. Finite sums from sequences within cells of partition of N. Journal of Combinatorial Theory (A), 17:1–11, 1974.
[6] P. Matet. Some filters of partitions. The Journal of Symbolic Logic, 53:540– 553, 1988.
[7] A.R.D. Mathias. Happy families. Annals of Mathematical logic, 12:59– 111, 1977.
[8] F.P. Ramsey. On a problem of formal logic. London Mathematical Society, 30:264–286, 1930.
[9] S. Shelah and O. Spinas. The distributivity numbers of finite products of P(ω)/fin. Fundamenta Mathematicae, 158:81–93, 1998.Aquesta tesi és una contribució a la teoria combinatria de conjunts, específcament a la teoria de Ramsey, que estudia les particions de conjunts infinits. El principi combinatori bàsic diu que per a tota partició del conjunt dels nombres naturals en un nombre finit de classes hi ha un conjunt infinit de nombres naturals que està inclòs en una de les classes. El teorema de Ramsey [6], que hom pot veure com una generalització d'aquest principi bàsic, tracta de les particions del conjunt [N]k de tots els subconjunts de k elements de nombres naturals.
Afirma que, per a cada k >/=1 i cada partició de [N]k en un nombre finit de classes, existeix un subconjunt infinit de nombres naturals, M, tal que tots els subconjunts de k elements de M pertanyen a una mateixa classe. Els conjunts amb aquesta propietat són homogenis per a la partició.
En [3], Neil Hindman va demostrar un resultat de tipus Ramsey que Graham i Rotschild havien conjecturat en [2]. El teorema de Hindman afirma que si el conjunt de nombres naturals es divideix en dues classes, almenys una d'aquestes classes conté un conjunt infinit tal que totes les sumes finites d'elements distints del conjunt pertanyen a la mateixa classe. La demostració original del Teorema de Hindman va ser simplificada per James Baumgartner en [1].
En aquesta tesi donem noves demostracions d'aquests dos teoremes, basades en la tècnica del forcing. Després, analitzem els ordres parcials corresponents i n'estudiem les propietats i la relació amb altres ordres coneguts semblants. L'ordre parcial emprat en la demostració del teorema de Ramsey és equivalent al forcing de Mathias, definit en [5]. L'ordre parcial que apareix en la prova del teorema de Hindman, que anomenem PFIN, serà l'objecte d'estudi principal de la tesi.
En el primer capítol donem algunes definicions bàsiques i enunciem alguns teoremes coneguts que necessitarem més endavant.
El segon capítol conté la demostració del teorema de Ramsey. Usant la tècnica del forcing, produïm un conjunt homogeni per a una partició donada. L'ordre parcial que utilitzem és equivalent al de Mathias.
En el tercer capítol, modifiquem la demostració de Baumgartner del teorema de Hindman per definir un ordre parcial, que anomenem PC , a partir del qual, mitjançant arguments de forcing, obtenim el conjunt homogeni buscat. Aquí, C es un conjunt infinit de conjunts finits disjunts de nombres naturals, i PC afegeix una successió de conjunts finits de nombres naturals amb la propietat de que totes les unions finites de elements d'aquesta successió pertanyen al conjunt C . A partir d'aquesta successió és fàcil obtenir un conjunt homogeni per a la partició del teorema original de Hindman. L'ordre parcial PC és similar a l'ordre definit per Pierre Matet en [4] i també al forcing de Mathias. Per això, és natural preguntar-nos si aquests ordres són equivalents o no.
En el quart capítol treballem amb un ordre parcial que és equivalent a PC i que anomenem PFIN. Mostrem que PFIN té les propietats següents:
(1) A partir d'un filtre genèric per a PFIN obtenim una successió infinita de conjunts finits de nombres naturals. Com en el cas del real de Mathias, aquesta successi_o ens permet reconstruir tot el filtre genèric.
(2) PFIN afegeix un real de Mathias, que és un "dominating real". Ara bé, si afegim un "dominating real" afegim també un "splitting real". Aquest fet ens permet concloure que PFIN no és equivalent al forcing de Matet, ja que el forcing de Matet no afegeix "splitting reals"
(3) PFIN es pot veure com una iteració de dos ordres parcials, el primer dels quals és "sigma-closed" i el segon és "sigma-centered".
(4) PFIN té la "pure decision property".
(5) PFIN no afegeix reals de Cohen.
En el cinquè capítol demostrem que PFIN afegeix un real de Matet i, finalment, que el forcing de Mathias no afegeix reals de Matet. Això és com demostrem que el forcing de Mathias i PFIN no són ordres equivalents.
Al final del capítol donem una aplicació de PFIN. Demostrem que un cert ordre definit per Saharon Shelah en [7], que anomenem M2, és una projecció de PFIN. Això implica que si G és un filtre PFIN-genèric sobre V, l'extensió V [G] conté també un filtre genèric per a M2. L'ordre M2 és una mena de producte de dues cópies del forcing de Mathias.
REFERÈNCIES
[1] J.E. Baumgartner. A short proof of Hindman's theorem, Journal of Combinatorial Theory, 17: 384-386, (1974).
[2] R.L. Graham and B.L. Rothschild. Ramsey's theorem for m-parameter sets, Transaction American Mathematical Society, 159: 257-292, (1971).
[3] N. Hindman. Finite sums from sequences within cells of partitions of N, Journal of Combinatorial Theory (A), 17: 1-11, (1974).
[4] P. Matet. Some _lters of partitions, The Journal of Symbolic Logic, 53: 540-553, (1988).
[5] A.R.D. Mathias. Happy families, Annals of Mathematical Logic, 12: 59-111, (1977).
[6] F.P. Ramsey. On a problem of formal logic, London Mathematical Society, 30:264_D286, 1930.
[7] S. Shelah and O. Spinas. The distributivity numbers of finite products of P(!)=fin, Fundamenta Mathematicae, 158:81_D93, 1998
Discrimination of milks with a multisensor system based on layer-by-layer films
Producción CientíficaA nanostructured electrochemical bi-sensor system for the analysis of milks has been developed using the layer-by-layer technique. The non-enzymatic sensor [CHI+IL/CuPcS]2, is a layered material containing a negative film of the anionic sulfonated copper phthalocyanine (CuPcS) acting as electrocatalytic material, and a cationic layer containing a mixture of an ionic liquid (IL) (1-butyl-3-methylimidazolium tetrafluoroborate) that enhances the conductivity, and chitosan (CHI), that facilitates the enzyme immobilization. The biosensor ([CHI+IL/CuPcS]2-GAO) results from the immobilization of galactose oxidase on the top of the LbL layers. FTIR, UV–vis, and AFM have confirmed the proposed structure and cyclic voltammetry has demonstrated the amplification caused by the combination of materials in the film. Sensors have been combined to form an electronic tongue for milk analysis. Principal component analysis has revealed the ability of the sensor system to discriminate between milk samples with different lactose content. Using a PLS-1 calibration models, correlations have been found between the voltammetric signals and chemical parameters measured by classical methods. PLS-1 models provide excellent correlations with lactose content. Additional information about other components, such as fats, proteins, and acidity, can also be obtained. The method developed is simple, and the short response time permits its use in assaying milk samples online.Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2015-67482-R)Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project VA-011U16)Junta de Castilla y León (grant BOCYL-D-4112015-9
How has the COVID-19 pandemic affected the climate change debate on Twitter?
Climate change and the COVID-19 pandemic share many similarities. However, in the past months, concerns have increased about the fact the health emergency has put on hold during the pandemic many climate adaptation and mitigation policies. We focus our attention on understanding the role of the recent health emergency on the transmission of information related to climate change, jointly with other socio-economic variables, social norms, and cultural dimensions. In doing so, we create a unique dataset containing the number of tweets written with specific climate related keywords per country worldwide, as well as country specific socio-economic characteristics, relevant social norms, and cultural variables. We find that socio-economic variables, such as income, education, and other risk-related variables matter in the transmission of information about climate change and Twitter activity. We also find that the COVID-19 pandemic has significantly decreased the overall number of messages written about climate change, postponing the climate debate worldwide; but particularly in some vulnerable countries. This shows that in spite of the existing climate emergency, the current pandemic has had a detrimental effect over the short-term planning of climate policies in countries where climate action is urgentAuthors acknowledge financial support from Spanish Agency of Research (Agencia Estatal de Investigación). Grant number “PID2019-111255RB-100”S
Hot in Twitter: Assessing the emotional impacts of wildfires with sentiment analysis
[Abstract]: Social media generates a significant amount of information in terms of perceptions, emotions, and sentiments.
We present an economic analysis using the information provided by Twitter messages, describing impressions
and reactions to wildfires occurring in Spain and Portugal. We use natural language processing techniques to
analyze this text information. We generate a hedonometer estimate on how sentiments about wildfires vary with
exposure, measured via Euclidean distance from the catastrophic event, and air quality. We find that direct
exposure to wildfires significantly decreases the expressed sentiment score and increases the expressions of fear
and political discontent (protest). Economic valuation of these losses has been computed to be between
1.49€–3.50€/year/Kilometer of distance to the closest active fire. Welfare losses in terms of air quality have been
computed as 4.43€–6.59€/day of exposure.Agencia Estatal de
Investigacion, ´ RETOS program, grant number PID2019-111255RB-I0
Why is the market for hybrid electric vehicles (HEVs) moving slowly?
Hybrid electric vehicles (HEVs) could be a good short term option to help achieve global targets regarding road transport greenhouse gas emissions. Several common and country-specific public policies based on price or tax rebates are established in order to encourage the adoption of HEVs. The present research empirically assesses market preferences for HEVs in Spain, looking at the role of subsidies. An interactive internet-based survey was conducted in a representative sample (N = 1,200) of Spanish drivers. Drivers are willing to pay an extra amount of €1,645 for a HEV model compared to a conventional vehicle, premium which is well below the price markup for these cars. Therefore, current levels of economic subsidies applied in isolation to promote these types of vehicles may have a quite limited effect in extending their use. Overall, it is found that drivers have clear misconceptions about HEVs, which affect their purchasing choices and perceptions. Therefore, a policy mix of various incentives (including informational campaigns) may be required in order to stimulate the demand for HEVsThis work was supported by Fundación Ramón Areces (http://www.fundacionareces.es), Dr. Maria Loureiro; Secretaría de Estado de Investigación, Desarrollo e Innovación, ECO2016-79446-R, Dr. Maria LoureiroS
The impact of protest responses in choice experiments: an application to a Biosphere Reserve Management Program
Aim of study: To identify protest responses and compute welfare estimates with and without the inclusion of such responses using follow-up statements in a choice experiment exercise. To our knowledge, this is one of the first empirical applications that, following the conventional treatment used in contingent valuation methodology, explicitly deals with the treatment and identification of protest responses in choice experiments.
Area of study: the Eo, Oscos y Terras de Burón Biosphere Reserve sited between the regions of Galicia and Asturias. We are interested in the influence of such responses on preference elicitation for alternative management actions in this Reserve.
Materials and methods: A face-to-face survey conducted in a sample of residents and non-residents of this Reserve. In total, more than 450 surveys were collected.
Main results show that protest responses are fairly common in choice experiments, and their analysis affects the statistical performance of the empirical models as well as the valuation estimates. In fact, when the sample is corrected by protest responses, its size decreases to 303 individuals. Furthermore, we can observe that protest responses are triggered by a less positive attitude towards the wolf.
Research highlight: Protest responses are a common issue in choice experiments and, therefore, future exercises should consider them explicitly, as earlier contingent valuation studies have.The authors acknowledge funding support fromFundación Caixa Galicia-Claudio San Martín. Project: «Valoración medioambiental, cultural y paisajística de los espacios rurales» (Number: 2005-CL046).S
The continuous-time hidden Markovmodel based on discretization. Properties of estimators and applications
Universidad de Granada/CBU
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