8,564 research outputs found
A logic approach for exceptions and anomalies in association rules
Association rules have been used for obtaining information hidden in a
database. Recent researches have pointed out that simple associations are
insu cient for representing the diverse kinds of knowledge collected in a
database. The use of exceptions and anomalies deal with a di erent type
of knowledge sometimes more useful than simple associations. Moreover ex-
ceptions and anomalies provide a more comprehensive understanding of the
information provided by a database.
This work intends to go deeper in the logic model studied in [5]. In the
model, association rules can be viewed as general relations between two or
more attributes quanti ed by means of a convenient quanti er. Using this
formulation we establish the true semantics of the distinct kinds of knowledge
we can nd in the database hidden in the four folds of the contingency table.
The model is also useful for providing some measures for assessing the validity
of those kinds of rulesPeer Reviewe
A Cholinergic Synaptically Triggered Event Participates in the Generation of Persistent Activity Necessary for Eye Fixation
An exciting topic regarding integrative properties of the nervous system is how transient motor commands or brief sensory stimuli are able to evoke persistent neuronal changes, mainly as a sustained, tonic action potential firing. A persisting firing seems to be necessary for postural maintenance after a previous movement. We have studied in vitro and in vivo the generation of the persistent neuronal activity responsible for eye fixation after spontaneous eye movements. Rat sagittal brainstem slices were used for the intracellular recording of prepositus hypoglossi (PH) neurons and their synaptic activation from nearby paramedian pontine reticular formation (PPRF) neurons. Single electrical pulses applied to the PPRF showed a monosynaptic glutamatergic projection on PH neurons, acting on AMPA-kainate receptors. Train stimulation of the PPRF area evoked a sustained depolarization of PH neurons exceeding (by hundreds of milliseconds) stimulus duration. Both duration and amplitude of this sustained depolarization were linearly related to train frequency. The train-evoked sustained depolarization was the result of interaction between glutamatergic excitatory burst neurons and cholinergic mesopontine reticular fibers projecting onto PH neurons, because it was prevented by slice superfusion with cholinergic antagonists and mimicked by cholinergic agonists. As expected, microinjections of cholinergic antagonists in the PH nucleus of alert behaving cats evoked a gaze-holding deficit consisting of a re-centering drift of the eye after each saccade. These findings suggest that a slow, cholinergic, synaptically triggered event participates in the generation of persistent activity characteristic of PH neurons carrying eye position signals
Decoherence in a double-slit quantum eraser
We study and experimentally implement a double-slit quantum eraser in the
presence of a controlled decoherence mechanism. A two-photon state, produced in
a spontaneous parametric down conversion process, is prepared in a maximally
entangled polarization state. A birefringent double-slit is illuminated by one
of the down-converted photons, and it acts as a single-photon two-qubits
controlled not gate that couples the polarization with the transversal momentum
of these photons. The other photon, that acts as a which-path marker, is sent
through a Mach-Zehnder-like interferometer. When the interferometer is
partially unbalanced, it behaves as a controlled source of decoherence for
polarization states of down-converted photons. We show the transition from
wave-like to particle-like behavior of the signal photons crossing the
double-slit as a function of the decoherence parameter, which depends on the
length path difference at the interferometer.Comment: Accepted in Physical Review
Patterns of spatial changes on demersal species in the Gulf of Cadiz and northern Alboran Sea
The Gulf of Cadiz (GoC) in the Atlantic Ocean and the northern Alboran Sea (AS) in the Mediterranean Sea are part of an extremely important oceanographic complex in terms of water exchange between the Atlantic and the Mediterranean through the
Strait of Gibraltar. Besides its significant role as an ecological transition system, it is unknown whether regional and local envi ronmental drivers affect similarly species inhabiting these two adjacent and connected ecosystems. This study analyses the spatial shifts of representative demersal species and their response to the environmental and demographic drivers in these two regions, using information from two trawl surveys carried out in the GoC and in the AS from 1994 to 2015. Species distribution trends were observed in both basins. However, they were more evident in the GoC, where six out of eleven species presented temporal trends, than in the AS, where only two species displayed significant distribution changes. In both basins, these species showed geographic displacements towards the Strait of Gibraltar. Also, a high percentage of species presented significant differences in mean depth
distribution on the two sides of the Strait of Gibraltar. Our study shows a general heterogeneity and independence in the drivers influencing species distributions in the two areas. GoC was highly influenced by both large- and regional-scale climate factors, which affected several species, while in AS the diversity of drivers was greater, with species density being the most common. This study provides a scientific basis for improving ecosystem-based management measures in these important transitional ecosystems.Postprint0,56
Un nuevo depĂłsito de armas del Bronce Final en el rĂo Guadalquivir
This paper describes a new Late Bronze Age weapon hoard from the river Guadalquivir (prov. Seville, Spain). The hoard consists of a carp's tongue sword, a ferrule, and a socketed spearhead.
The absence of good archaeological contexts for this kind of weapon hoard has made dating them difficult, but recently a carp's tongue sword has been found in a stratigraphic context with a date of 950-850 B. C.
These finds suggest perhaps that there is some relation between these funerary weapon hoards and water (rivers, lakes, the sea, etc.).Presentamos un nuevo depĂłsito de armas pertenecientes al Bronce Final hallado en el RĂo Guadalquivir en los trabajos de dragado del mismo a principios de los años ochenta.
Consta de una espada de lengua de carpa y de una punta y un regatĂłn de lanza, todas de bronce. SegĂşn los datos documentados hasta ahora para los demás depĂłsitos andaluces de estas caracterĂsticas, su vinculaciĂłn con zonas acuáticas parece confirmarse casi en la totalidad de los casos, constituyendo un dato importante más, favorable a un nuevo planteamiento de las costumbres, probablemente funerarias, de este momento cultural de AndalucĂa
Association of shivering threshold time with body composition and brown adipose tissue in young adults
Purpose: Brown adipose tissue (BAT) increases metabolic heat production in response to cold exposure. Body size
and composition are involved in the human cold response, yet the influence of BAT herein have not fully been
explored. Here, we aimed to study the association of the cold-induced shivering threshold time with body
composition, BAT, the perception of shivering and skin temperature in young adults.
Methods: 110 young healthy adults (81 females; age = 21.7 ± 2.1 years, BMI = 24.2 ± 4.3 kg/m2) underwent 2 h
of individualized cooling, followed by the quantification of BAT using a18F-fluorodeoxyglucose ([18F]FDG)
positron emission tomography-computed tomography (PET-CT) scan. Body mass index (BMI), lean mass, fat mass
and body surface area (BSA) were also measured. Shivering threshold time was defined as the time until shivering
occurred using an individualized cooling protocol.
Results: The shivering threshold time was on average 116.1 min for males and 125.8 min for females, and was
positively associated to BMI (β = 3.106; R2 = 0.141; p = 0.001), lean mass (β = 2.295; R2 = 0.128; p = 0.001)
and fat mass (β = 1.492; R2 = 0.121; p = 0.001) in females, but not in males (all p ≥ 0.409). The shivering
threshold time was positively associated with BSA in males (p = 0.047) and females (p = 0.001), but it was not
associated with BAT volume or [18F]FDG uptake nor with the perception of shivering and skin temperature
perception in both sexes.
Conclusion: The shivering threshold time is positively associated with whole-body adiposity and lean mass in
females, but not in males. The shivering threshold time was positively associated with BSA, but no association
was observed with BAT nor with the perception of shivering or skin temperature. Future research should consider
the influence of body composition when applying cooling protocols among individuals with different phenotypical
features.Spanish Government PI13/01393
PTA 12264-IRetos de la Sociedad DEP 2016-79512-REuropean CommissionSpanish Government FPU 13/03410Fundacion Iberoamericana de Nutricion (FINUT)Redes Tematicas de Investigacion Cooperativa RETIC Red SAMID RD16/0022AstraZenecaUniversity of Granada Plan Propio de Investigacion 2016 - Excellence actions: Unit of Excellence on Exercise and Health (UCEES)Plan Propio de Investigacion 2018: Programa ContratosPuenteJunta de Andalucia, Consejeria de Conocimiento, Investigacion y Universidades (ERDF) SOMM17/6107/UGRFundacion Carolina C.2016-574,961Fundacion Alfonso Martin EscuderoMinisterio de Universidades y la Union Europea-NextGenerationEU RR_C_2021_0
Untangling the eclectronic propierties of triindole-based semiconductors
Organic semiconductors have emerged as an important class of materials that offer interesting prospects for high throughput, low-cost and flexible electronic circuits. In this sense, triindole-based systems have demonstrated great potential as p-type semiconductors in organic field-effect transistors (OFETs).[1] Recently, we have performed a combined experimental and theoretical study of three new crystalline N-trimethyltriindoles endowed with different functionalities at 3, 8 and 13 positions, either unsubstituted or with three methoxy or acetyl groups (Figure 1a), with the main goal of exploring the correlation between the electronic nature of the substituents and their solid-state organization, electronic properties and semiconductor behavior.[2] On the other hand, the design and synthesis of covalent organic framework materials (constructed from the union of different covalently linked conjugated platforms) are being deeply investigated in organic electronics.[3] In line with this , we have also investigated how the structural and the electronic properties of 2D triindole-based polymers (Figure 1b) can be modulated by the (i) modification of the linkage position from para (T2) to meta (T3), (ii) by the insertion of different Ď€-bridges between the cores and (iii) by the increment of the number of Ď€-bridges from 3 to 6 units (T2,3).[4] Overall, the results of this work open the door to the control of the degree of the Ď€-conjugation for their subsequent synthesis and real application in organic electronic devices.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
Anti-Angiogenic Treatment (Sunitinib) for Disseminated Malignant Haemangiopericytoma: A Case Study and Review of the Literature
Introduction: A meningeal haemangiopericytoma (HP) is a mesenchymal tumour that makes up less than 1% of all CNS tumours. HPs arise from pericytes and present high rates of recurrence and distant metastasis. The primary treatment option is surgery. When the disease is disseminated, chemotherapy produces a weak and short-lived response; therefore, new drugs are needed. Case Presentation: We describe the case of a 65-year-old woman with a 13-year history of recurrent HP. After local treatment with radiotherapy, she developed metastases that required systemic treatment, and treatment with sunitinib, an oral inhibitor of the vascular endothelial growth factor receptor and the platelet-derived growth factor receptor, was initiated. As a result, radiological stabilisation of the systemic disease was maintained for over 12 months. Conclusions: Anti-angiogenic agents can be useful for treating disseminated HP, but further studies are needed to confirm their possible role in controlling metastatic disease
MOTION OF A LARGE OBJECT IN A 2D BUBBLING FLUIDIZED BED
The motion of a large object in a bubbling fluidized bed is experimentally studied using digital image analysis. A wide range of fluidized bed applications involves the motion of large objects within the bed, such objects being reactants, catalysts, agglomerates, etc.
The experiments were run in a 2D bubbling fluidized bed with glass spheres as bed material. The object motion is measured using tracking techniques, while independent measurements of the dense phase velocity (using PIV) and bubble velocity were carried out. The effect of the excess gas velocity on the object motion was also analyzed.
It is generally accepted that objects with densities in a range around the bed density will describe sinking-rising cycles throughout the whole bed, where the sinking motion is similar to that of the dense phase, and the rising motion is composed of a number of sudden jerks or jumps, as a result of the raising effect of passing bubbles. This work characterized the circulation patterns of an object with a density similar to that of the bed material, but much larger in size. A comparison between the object rising motion and the local bubble motion provided evidence for the study of the bubble ability to raise the object, depending on the bubble velocity and size. A comparison between the object sinking motion and the dense phase motion served to analyze the minor effect of buoyancy forces over the object sinking motion. Finally, the combined effects of the maximum attained depth and the number of jerks in the circulation time is studied, with some insight in the multiple-jerks phenomenon
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