Game of Tenure: the role of “hidden” citations on researchers’ ranking in Ecology

Field ecologists and macroecologists often compete for the same grants and academic positions, with the former producing primary data that the latter generally use for model parameterization. Primary data are usually cited only in the supplementary materials, thereby not counting formally as citations, creating a system where field ecologists are routinely under-acknowledged and possibly disadvantaged in the race for funding and positions. Here, we explored how the performance of authors producing novel ecological data would change if all the citations to their work would be accounted for by bibliometric indicators. We collected the track record of >2300 authors from Google Scholar and citation data from 600 papers published in 40 ecology journals, including field-based, conservation, general ecology, and macroecology studies. Then we parameterized a simulation that mimics the current publishing system for ecologists and assessed author rankings based on number of citations, H-Index, Impact Factor, and number of publications under a scenario where supplementary citations count. We found weak evidence for field ecologists being lower ranked than macroecologists or general ecologists, with publication rate being the main predictor of author performance. Current ranking dynamics were largely unaffected by supplementary citations as they are 10 times less than the number of main text citations. This is further exacerbated by the common practice of citing datasets assembled by previous research or data papers instead of the original articles. While accounting for supplementary citations does not appear to offer a solution, researcher performance evaluations should include criteria that better capture authors’ contribution of new, publicly available data. This could encourage field ecologists to collect and store new data in a systematic manner, thereby mitigating the data patchiness and bias in macroecology studies, and further accelerating the advancement of ecology and related areas of biogeography

Evaluating the reliability of NAND multiplexing with PRISM

Probabilistic-model checking is a formal verification technique for analyzing the reliability and performance of systems exhibiting stochastic behavior. In this paper, we demonstrate the applicability of this approach and, in particular, the probabilistic-model-checking tool PRISM to the evaluation of reliability and redundancy of defect-tolerant systems in the field of computer-aided design. We illustrate the technique with an example due to von Neumann, namely NAND multiplexing. We show how, having constructed a model of a defect-tolerant system incorporating probabilistic assumptions about its defects, it is straightforward to compute a range of reliability measures and investigate how they are affected by slight variations in the behavior of the system. This allows a designer to evaluate, for example, the tradeoff between redundancy and reliability in the design. We also highlight errors in analytically computed reliability bounds, recently published for the same case study

Gene gating at nuclear pores prevents the formation of R loops

Transcription is an important source of genetic variability. A large amount of transcription-associated genome variation arises from the unscheduled formation of R loops. We have recently found that physical proximity of chromatin to nuclear pores prevents the formation of pathological R loops during transcription. Our study opens new perspectives to understand genome stability as a function of nuclear location

Space-Dimension Models of Spectrum Usage for Cognitive Radio Networks.

The dynamic spectrum access (DSA) principle, relying on the cognitive radio (CR) paradigm, allows users to access spectrum over time intervals or spatial areas where it remains unused. Due to the opportunistic nature of DSA/CR, the behavior and performance of DSA/CR networks depends on the perceived spectrum usage pattern. An accurate modeling of spectrum occupancy therefore becomes essential in the context of DSA/CR. In this context, this paper addresses the problem of accurately modeling the spectrum occupancy pattern perceived by DSA/CR users in the spatial domain. A novel spatial modeling approach is introduced to enable a simple yet practical and accurate characterization of spectrum. First, a set of models is proposed to characterize and predict the average level of occupancy perceived by DSA/CR users at various locations based on the knowledge of some simple signal parameters. An extension is then proposed to characterize not only the average occupancy level but the instantaneous channel state perceived simultaneously by DSA/CR users observing the same transmitter from different locations as well. The validity and accuracy of the theoretical models are demonstrated with results from an extensive spectrum measurement campaign. Some illustrative examples of their potential applicability are presented and discussed as well

A probabilistic model for crystal growth applied to protein deposition at the microscale

A probabilistic discrete model for 2D protein crystal growth is presented. This model takes into account the available space and can describe growing processes of different nature due to the versatility of its parameters which gives the model great flexibility. The accuracy of the simulation is tested against a real protein (SbpA) crystallization experiment showing high agreement between the proposed model and the actual images of the nucleation process. Finally, it is also discussed how the regularity of the interface (i.e. the curve that separates the crystal from the substrate) affects to the evolution of the simulation.Comment: 13 pages, 12 figure

The inverse along an element in rings

[EN] Several properties of the inverse along an element are studied in the context of unitary rings. New characterizations of the existence of this inverse are proved. Moreover, the set of all invertible elements along a fixed element is fully described. Furthermore, commuting inverses along an element are characterized. The special cases of the group inverse, the (generalized) Drazin inverse and the Moore-Penrose inverse (in rings with involutions) are also considered.Benítez López, J.; Boasso, E. (2016). The inverse along an element in rings. The Electronic Journal of Linear Algebra. 31:572-592. doi:10.13001/1081-3810.3113S5725923

Link adaptation algorithms for improved delivery of delay- and error-sensitive packet-data services over wireless networks

Link Adaptation is a radio resource management technique that assesses the channel conditions and selects a transport mode, from a set of possible options, which is optimised for these conditions according to a predefined criterion. The optimum transport mode is commonly determined so as to maximise the throughput. Although this approach may be appropriate for best-effort services, its suitability for multimedia services, usually characterised by tight delay and error performance constraints, has been questioned. As a result, a number of alternative algorithms have been proposed in the literature. In this context, this paper presents and evaluates in a dynamic radio environment several Link Adaptation algorithms designed to enhance the provision of delay- and error-sensitive multimedia packet-data services over wireless systems. The obtained results demonstrate that significant improvements in terms of throughput, transmission delay, error performance and operation of Link Adaptation itself can be obtained with the proposed schemes.Postprint (published version

The inverse along an element in rings with an involution, Banach algebras and C*-algebras

[EN] Properties of the inverse along an element in rings with an involution, Banach algebras and C*-algebras will be studied unifying known expressions concerning generalized inverses.This work was supported by the Universidad Politecnica de Valencia [SP20120474].Benítez López, J.; Boasso, E. (2017). The inverse along an element in rings with an involution, Banach algebras and C*-algebras. Linear and Multilinear Algebra. 65(2):284-299. doi:10.1080/03081087.2016.1183559S28429965

Existence Criteria and Expressions of the (b, c)-Inverse in Rings and Their Applications

[EN] Let R be a ring. Existence criteria for the (b, c)-inverse are given. We present explicit expressions for the (b, c)-inverse by using inner inverses. We answer the question when the (b, c)-inverse of a ¿ R is an inner inverse of a. As applications, we give a unified theory of some well-known results of the {1, 3}-inverse, the {1, 4}-inverse, the Moore¿Penrose inverse, the group inverse and the core inverse.The first author is grateful to the China Scholarship Council for giving him a scholarship for his further study in Universitat Politecnica de Valencia, Spain.Xu, S.; Benítez López, J. (2018). Existence Criteria and Expressions of the (b, c)-Inverse in Rings and Their Applications. Mediterranean Journal of Mathematics. 15(1). https://doi.org/10.1007/s00009-017-1056-xS151Baksalary, O.M., Trenkler, G.: Core inverse of matrices. Linear Multilinear Algebra 58, 681–697 (2010)Ben-Israel, A., Greville, T.N.E.: Generalized Inverses: Theory and Applications, 2nd edn. Springer, New York (2003)Benítez, J., Boasso, E., Jin, H.W.: On one-sided $$(B,C)$$(B,C)-inverses of arbitrary matrices. Electron. J. Linear Algebra 32, 391–422 (2017). arXiv:1701.09054v1Boasso, E., Kantún-Montiel, G.: The $$(b,c)$$(b,c)-inverses in rings and in the Banach context. Mediterr. J. Math. 14, 112 (2017). https://doi.org/10.1007/s00009-017-0910-1BhaskaraRao, K.R.S.: The Theory of Generalized Inverses over Commutative Rings. Taylor and Francis, London (2002)Campbell, S.L., Meyer, C.D.: Generalized Inverses of Linear Transformations. Pitman, London (1979)Drazin, M.P.: A class of outer generalized inverses. Linear Algebra Appl. 436, 1909–1923 (2012)Drazin, M.P.: Left and right generalized inverses. Linear Algebra Appl. 510, 64–78 (2016)Green, J.A.: On the structure of semigroups. Ann. Math. 54(1), 163–172 (1951)Hartwig, R.E.: Block generalized inverses. Arch. Ration. Mech. Anal. 61, 197–251 (1976)Han, R.Z., Chen, J.L.: Generalized inverses of matrices over rings. Chin. Q. J. Math. 7(4), 40–49 (1992)Ke, Y.Y., Cvetković-Ilić, D.S., Chen, J.L., Višnjić J.: New results on $$(b, c)$$(b,c)-inverses. Linear Multilinear Algebra. https://doi.org/10.1080/03081087.2017.1301362Ke, Y.Y., Višnjić, J., Chen, J.L.: One-sided $$(b, c)$$(b,c)-inverses in rings (2016). arXiv:1607.06230v1Mary, X.: On generalized inverse and Green’s relations. Linear Algebra Appl. 434, 1836–1844 (2011)Mary, X., Patrício, P.: Generalized inverses modulo $$\cal{H}$$H in semigroups and rings. Linear Multilinear Algebra 61(8), 1130–1135 (2013)von Neumann, J.: On regular rings. Proc. Natl. Acad. Sci. USA 22(12), 707–713 (1936)Rakić, D.S.: A note on Rao and Mitra’s constrained inverse and Drazin’s (b, c) inverse. Linear Algebra Appl. 523, 102–108 (2017)Rakić, D.S., Dinčić, N.Č., Djordjević, D.S.: Group, Moore–Penrose, core and dual core inverse in rings with involution. Linear Algebra Appl. 463, 115–133 (2014)Rao, C.R., Mitra, S.K.: Generalized inverse of a matrix and its application. In: Proceedings of the Sixth Berkeley Symposium on Mathematics, Statistics and Probability, vol. 1, pp. 601–620. University of California Press, Berkeley (1972)Wei, Y.M.: A characterization and representation of the generalized inverse $$A^{(2)}_{T, S}$$AT,S(2) and its applications. Linear Algebra Appl. 280, 87–96 (1998)Wang, L., Chen, J.L., Castro-González, N.: Characterizations of the $$(b, c)$$(b,c)-inverse in a ring (2015). arXiv:1507.01446v1Xu, S.Z., Chen, J.L., Zhang, X.X.: New characterizations for core inverses in rings with involution. Front. Math. China 12(1), 231–246 (2017

La comprensión de textos en la resolución de problemas. Un acercamiento cognitivo

La presente investigación identifica las operaciones de segmentación y recontextualización en la comprensión de problemas no rutinarios en matemáticas, así como el cambio de representación para establecer el vínculo entre la comprensión del texto y el discurso explicativo. La experiencia se llevó a cabo en la unidad de aprendizaje de cálculo diferencial por alumnos de Nivel Medio Superior (16-17 años). El análisis de la producción de los alumnos se realizó a través de cuatro momentos, lo cual permitió identificar los indicadores que contribuyeron para valorar los procedimientos desarrollados. A nivel de resultados, hay un desarrollo manifiesto de capacidades y habilidades, así como la influencia del contenido cognitivo y redaccional en la comprensión de textos en matemáticas. Los registros y las transcripciones de las clases fueron analizados considerando un modelo particular de la investigación cualitativa, empírico / experimental