Aprendizaje en industria lítica mediante el concepto de talla discoide

Brevemente, la arqueología experimental ha permitido la reconstrucción de los procesos tecnológicos del pasado así como las estrategias que se siguieron y los productos obtenidos en base al registro arqueológicoThe experimental archaeology has allowed the reconstruction of the past technical processes, as well as the strategies used and the products obtained based on the archaeological recor

Weight-2 input sequences of 1/n convolutional codes from linear systems point of view

Convolutional codes form an important class of codes that have memory. One natural way to study these codes is by means of input state output representations. In this paper we study the minimum (Hamming) weight among codewords produced by input sequences of weight two. In this paper, we consider rate 1/n and use the linear system setting called (A,B,C,D) input-state-space representations of convolutional codes for our analysis. Previous results on this area were recently derived assuming that the matrix A, in the input-state-output representation, is nonsingular. This work completes this thread of research by treating the nontrivial case in which A is singular. Codewords generated by weight-2 inputs are relevant to determine the effective free distance of Turbo codes.The research of the second author was supported by Spanish I+D+i project PID2019-108668GB-I00 of MCIN/AEI/10.13039/501100011033

The impact of firms' financial position on fixed investment and employment : an analysis for Spain

Utilizando una muestra de gran tamaño de empresas no financieras españolas, este trabajo analiza el impacto que la situación financiera de las sociedades tiene sobre sus decisiones de inversión y contratación de empleados. Los resultados indican que la posición patrimonial de las empresas es relevante a la hora de explicar la inversión empresarial y los niveles de empleo, ya que el flujo de caja, el endeudamiento y la carga financiera son relevantes a la hora de explicar la evolución de ambas variables. Asimismo, los resultados obtenidos revelan que el impacto de la posición financiera de las sociedades sobre estas variables es no lineal, siendo más acusado para aquellas empresas que presentan una posición financiera menos saneada. También sugieren que el papel que desempeñan los factores financieros a la hora de explicar la evolución de la inversión y del empleo es mayor en períodos recesivosUsing a large sample of Spanish companies, this paper investigates the impact that firms’ financial health has on their investment and employment decisions. The results indicate that firms’ financial position is important for explaining firms’ capital expenditures and their employment levels, since cash flow, indebtedness and the debt burden appear to be relevant for explaining investment and employment dynamics. Likewise, the results obtained point to a non-linear impact of financial position on these decisions, this being larger for companies in a less sound financial situation, and suggest that the role of financial factors in explaining investment and employment dynamics is likely to be greater in recessionary period

1/n Turbo codes from linear system point of view

The performance of turbo codes at the error floor region is largely determined by the effective free distance, which corresponds to the minimum Hamming weight among all codeword sequences generated by input sequences of weight two. In this paper, we study turbo codes of dimension one obtained from the concatenation of two equal codes and present an upper bound on the effective free distance of a turbo code with these parameters defined over any finite field. We do that making use of the so-called (A, B, C, D) state-space representations of convolutional codes and restrict to the case where A is invertible. A particular construction, from a linear systems point of view, of a recursive systematic convolutional code of rate 1/n so that the effective free distance of the corresponding turbo code attains this upper bound is also presented.D. Napp was partially supported by the the Universitat d’Alacant (Grant No. VIGROB-287) and Generalitat Valenciana (Grant No. AICO/2017/128). V. Herranz and C. Perea were supported by the Ministerio de Economa, Industria y Competitividad within project TIN2016-80565-R

Parallel concatenated convolutional codes from linear systems theory viewpoint

The aim of this work is to characterize two models of concatenated convolutional codes based on the theory of linear systems. The problem we consider can be viewed as the study of composite linear system from the classical control theory or as the interconnection from the behavioral system viewpoint. In this paper we provide an input–state–output representation of both models and introduce some conditions for such representations to be both controllable and observable. We also introduce a lower bound on their free distances and the column distances

Recent Theories about the Syntax of Biblical Hebrew Verb

En esta segunda parte del artículo se contrastan las teorías presentadas en la parte primera con diversos textos del libro de Ezequiel, con el objeto de hacer una valoraci6n critica de cada una de ellas. A la luz de los textos, quedan de manifiesto las carencias de las posturas aspectual y temporal de Waltke-O'Connor y Revell respectivamente, y se constatan por el contrario las amplias posibilidades de la aproximación textual.In this second part of the paper 1 try to test the validity of the different theories that have been discussed in the first part when they are put in contact with the texts of Ezekiel's Book. The point is to make a critical judgment of each of them. When 1 have to explain the texts, it comes out to the light that the aspectual-temporal theory is full of deficiencies. On the contrary, the textual view allows a wide range of possibilities

Las matrices de Toeplitz en la construcción de códigos convolucionales perforados

En este trabajo presentamos la modelización de la técnica de perforación de códigos convolucionales introducida por McEliece desde el punto de vista de sistemas. Aplicando esta técnica a un (2, 1, 1)-código convolucional óptimo y teniendo en cuenta las propiedades de las matrices de Toeplitz, construimos un nuevo (3, 2, 1)-código óptimo

Influence of gut microbiota on neuropsychiatric disorders

The last decade has witnessed a growing appreciation of the fundamental role played by an early assembly of a diverse and balanced gut microbiota and its subsequent maintenance for future health of the host. Gut microbiota is currently viewed as a key regulator of a fluent bidirectional dialogue between the gut and the brain (gut-brain axis). A number of preclinical studies have suggested that the microbiota and its genome (microbiome) may play a key role in neurodevelopmental and neurodegenerative disorders. Furthermore, alterations in the gut microbiota composition in humans have also been linked to a variety of neuropsychiatric conditions, including depression, autism and Parkinson’s disease. However, it is not yet clear whether these changes in the microbiome are causally related to such diseases or are secondary effects thereof. In this respect, recent studies in animals have indicated that gut microbiota transplantation can transfer a behavioral phenotype, suggesting that the gut microbiota may be a modifiable factor modulating the development or pathogenesis of neuropsychiatric conditions. Further studies are warranted to establish whether or not the findings of preclinical animal experiments can be generalized to humans. Moreover, although different communication routes between the microbiota and brain have been identified, further studies must elucidate all the underlying mechanisms involved. Such research is expected to contribute to the design of strategies to modulate the gut microbiota and its functions with a view to improving mental health, and thus provide opportunities to improve the management of psychiatric diseases. Here, we review the evidence supporting a role of the gut microbiota in neuropsychiatric disorders and the state of the art regarding the mechanisms underlying its contribution to mental illness and health. We also consider the stages of life where the gut microbiota is more susceptible to the effects of environmental stressors, and the possible microbiota-targeted intervention strategies that could improve health status and prevent psychiatric disorders in the near future.Peer reviewe

Effects of a gluten-free diet on gut microbiota and immune function in healthy adult human subjects

7 pages, 1 figure, 3 tables.Diet influences the composition of the gut microbiota and host's health, particularly in patients suffering from food-related diseases. Coeliac disease (CD) is a permanent intolerance to cereal gluten proteins and the only therapy for the patients is to adhere to a life-long gluten-free diet (GFD). In the present preliminary study, the effects of a GFD on the composition and immune function of the gut microbiota were analysed in ten healthy subjects (mean age 30·3 years) over 1 month. Faecal microbiota was analysed by fluorescence in situ hybridisation (FISH) and quantitative PCR (qPCR). The ability of faecal bacteria to stimulate cytokine production by peripheral blood mononuclear cells (PBMC) was determined by ELISA. No significant differences in dietary intake were found before and after the GFD except for reductions (P = 0·001) in polysaccharides. Bifidobacterium, Clostridium lituseburense and Faecalibacterium prausnitzii proportions decreased (P = 0·007, P = 0·031 and P = 0·009, respectively) as a result of the GFD analysed by FISH. Bifidobacterium, Lactobacillus and Bifidobacterium longum counts decreased (P = 0·020, P = 0·001 and P = 0·017, respectively), while Enterobacteriaceae and Escherichia coli counts increased (P = 0·005 and P = 0·003) after the GFD assessed by qPCR. TNF-α, interferon-γ, IL-10 and IL-8 production by PBMC stimulated with faecal samples was also reduced (P = 0·021, P = 0·037, P = 0·002 and P = 0·007, respectively) after the diet. Therefore, the GFD led to reductions in beneficial gut bacteria populations and the ability of faecal samples to stimulate the host's immunity. Thus, the GFD may constitute an environmental variable to be considered in treated CD patients for its possible effects on gut health.This work was supported by grants AGL2008-01440/ALI and Consolider Fun-C-Food 20 CSD2007-00063 from the Spanish Ministry of Science and Innovation.Peer reviewe