Uso y efectividad de la relación estratégica comunitaria y el marketing en empresas del sector aeronáutico

La relación estratégica comunitaria busca la atracción y retención de clientes a través del entendimiento de los consumidores dentro del contexto social que los rodea, es decir, una estrategia de mercadeo que busca relaciones duraderas con sus clientes a través del desarrollo de las comunidades en las cuales están insertos, logrando así beneficios para ambas partes, empresa y comunidad, y una relación de negocios sostenible a través del tiempo. Este trabajo busca determinar cuál es el uso y la efectividad de la relación estratégica comunitaria y el marketing en el sector aeronáutico, pasando por la identificación de las estrategias de mercadeo, los conceptos comunitarios y el uso de las estrategias comunitarias al interior del sector. Para determinar esto, se tomó a Avianca como muestra en el período 2004-2014 y se buscó la relación de su mercadeo y sus acciones sociales con las estrategias comunitarias, sin embargo los resultados arrojaron que no existe una relación estratégica comunitaria en la compañía, a pesar de manejar conceptos comunitarios en sus proyectos sociales.

Factores asociados a fenómeno de no reflujo coronario en pacientes adultos llevados a angioplastia

Introducción: La disminución de flujo en los vasos coronarios sin presencia de oclusión, es conocido como fenómeno de no reflujo, se observa después de la reperfusión, su presentación oscila entre el 5% y el 50% dependiendo de la población y de los criterios diagnósticos, dicho suceso es de mal pronóstico, aumenta el riesgo de morir en los primeros 30 días posterior a la angioplastia (RR 2,1 p 0,038), y se relaciona con falla cardiaca y arritmias, por eso al identificar los factores a los cuales se asocia, se podrán implementar terapias preventivas. Metodología: Estudio de casos y controles pareado por médico que valoró el evento, para garantizar que no existieron variaciones inter observador, con una razón 1:4 (18:72), realizado para identificar factores asociados a la presencia de no reflujo en pacientes llevados a angioplastia, entre noviembre de 2010 y mayo de 2014, en la Clínica San Rafael de Bogotá, D.C. Resultados: La frecuencia del no reflujo fue del 2.89%. El Infarto Agudo de Miocardio con elevación del ST (IAMCEST) fue la única variable que mostró una asociación estadísticamente significativa con este suceso, valor de p 0,002, OR 8,7, IC 95% (2,0 – 36,7). Discusión: El fenómeno de no reflujo en esta población se comportó de manera similar a lo descrito en la literatura, siendo el IAMCEST un factor fuertemente asociado.

Resiliencia organizacional y capital psicológico

Desde la noción universal sobre la empresa como un sistema de interacción con un entorno determinado para alcanzar un objetivo, de manera planificada y en función de satisfacer las demandas de un mercado mediante la actividad económica, su viabilidad, sostenibilidad y crecimiento dependerán, por supuesto, de una serie de estrategias adecuadas no solo para tales fines, sino también para enfrentar diversidad de agentes endógenos y exógenos que puedan afectar el normal desempeño de su gestión. Estamos hablando de la importancia de la resiliencia organizacional y del Capital Psicológico. En un escenario tan impredecible como el de la economía mundial, donde la constante son los cambios en su comportamiento —unos propios de su dinámica e interdependencia, naturales de fenómenos como la globalización, y otros derivados de eventos disruptivos— hoy más que nunca es necesario implementar el modelo de la empresa resiliente, que es aquella entidad capaz de adaptarse y recuperarse frente a una perturbación. Al mismo tiempo, más allá de su tamaño, naturaleza u objeto social, es indispensable reconocer básicamente que toda organización está constituida por personas, lo cual implica la trascendencia que para su funcionamiento tiene el factor humano-dependiente, y por lo tanto se crea la necesidad de promover el Capital Psicológico y la resiliencia a nivel de las organizaciones a través de una cultura empresarial.

In situ calibration of atmospheric air conductivity instruments

A new method of measuring the total conductivity of atmospheric air is described. It depends on determination of the electrical relaxation time of a horizontal wire, mounted between two insulators, which is initially grounded and then allowed to charge freely. The total air conductivity derived is compared with that from an ion mobility spectrometer. Results from the two techniques agreed to within 1.2 fS m(-1). (c) 2006 American Institute of Physics.

Natural ventilation effects on temperatures within Stevenson screens

Thermometer screen properties are poorly characterised at low wind speeds. Temperatures from a large thermometer screen have been compared with those from an automatically shaded open-air fine-wire resistance thermometer. For the majority of 5-minute average measurements obtained between July 2008 and 2009, the screen and fine-wire temperatures agreed closely, with a median difference <0.05◦C. At low wind speeds however, larger temperature differences occurred. When calm (wind speed at 2 metres, u2, ≤ 0.1 m s−1), the difference between screen and open-air temperatures varied from −0.25◦C to +0.87◦C. At night with u2 < 0.5 m s−1, this difference was −0.14◦C to 0.39◦C, and, rarely, up to −0.68◦C to 1.38◦C. At the minimum in the daily temperature cycle, the semi-urban site at Reading had u2 < 1 m s−1 for 52% of the observations 1997–2008, u2 < 0.5 m s−1 for 34% and calm conditions for 20%. Consequently uncertainties in the minimum temperature measurements may arise from poor ventilation, which can propagate through calculations to daily average temperatures. In comparison with the daily minimum temperature, the 0900 UTC synoptic temperature measurement has a much lower abundance (5%) of calm conditions.

Torque in mooring chain. Part 1: Background and theory

Chain in both its forms - common (or stud-less) and stud-link - has many engineering applications. It is widely used as a component in the moorings of offshore floating systems, where its ruggedness and corrosion resistance make it an attractive choice. Chain exhibits some interesting behaviour in that when straight and subject to an axial load it does not twist or generate any torque, but if twisted or loaded when in a twisted condition it behaves in a highly non-linear manner, with the torque dependent upon the level of twist and axial load. Clearly an understanding of the way in which chains may behave and interact with other mooring components (such as wire rope, which also exhibits coupling between axial load and generated torque) when they are in service is essential. However, the sizes of chain that are in use in offshore moorings (typical bar diameters are 75 mm and greater) are too large to allow easy testing. This paper, which is in two parts, aims to address the issues and considerations relevant to torque in mooring chain. The first part introduces a frictionless theory that predicts the resultant torques and 'lift' in the links as non-dimensionalized functions of the angle of twist. Fortran code is presented in an Appendix, which allows the reader to make use of the analysis. The second part of the paper presents results from experimental work on both stud-less (41 mm) and stud-link (20.5 and 56 mm) chains. Torsional data are presented in both 'constant twist' and 'constant load' forms, as well as considering the lift between the links.

Modeling of carrier transport in nanowires

We consider a physical model of ultrafast evolution of an initial electron distribution in a quantum wire. The electron evolution is described by a quantum-kinetic equation accounting for the interaction with phonons. A Monte Carlo approach has been developed for solving the equation. The corresponding Monte Carlo algorithm is NP-hard problem concerning the evolution time. To obtain solutions for long evolution times with small stochastic error we combine both variance reduction techniques and distributed computations. Grid technologies are implemented due to the large computational efforts imposed by the quantum character of the model.

Wigner Transport models of the electron-phonon kinetics in quantum wires

Two quantum-kinetic models of ultrafast electron transport in quantum wires are derived from the generalized electron-phonon Wigner equation. The various assumptions and approximations allowing one to find closed equations for the reduced electron Wigner function are discussed with an emphasis on their physical relevance. The models correspond to the Levinson and Barker-Ferry equations, now generalized to account for a space-dependent evolution. They are applied to study the quantum effects in the dynamics of an initial packet of highly nonequilibrium carriers, locally generated in the wire. The properties of the two model equations are compared and analyzed.

Visual surveillance for moving vehicles

An overview is given of a vision system for locating, recognising and tracking multiple vehicles, using an image sequence taken by a single camera mounted on a moving vehicle. The camera motion is estimated by matching features on the ground plane from one image to the next. Vehicle detection and hypothesis generation are performed using template correlation and a 3D wire frame model of the vehicle is fitted to the image. Once detected and identified, vehicles are tracked using dynamic filtering. A separate batch mode filter obtains the 3D trajectories of nearby vehicles over an extended time. Results are shown for a motorway image sequence.

Bottom-up, not top-down, modulation of imitation by human and robotic models

Visual observation of human actions provokes more motor activation than observation of robotic actions. We investigated the extent to which this visuomotor priming effect is mediated by bottom-up or top-down processing. The bottom-up hypothesis suggests that robotic movements are less effective in activating the ‘mirror system’ via pathways from visual areas via the superior temporal sulcus to parietal and premotor cortices. The top-down hypothesis postulates that beliefs about the animacy of a movement stimulus modulate mirror system activity via descending pathways from areas such as the temporal pole and prefrontal cortex. In an automatic imitation task, subjects performed a prespecified movement (e.g. hand opening) on presentation of a human or robotic hand making a compatible (opening) or incompatible (closing) movement. The speed of responding on compatible trials, compared with incompatible trials, indexed visuomotor priming. In the first experiment, robotic stimuli were constructed by adding a metal and wire ‘wrist’ to a human hand. Questionnaire data indicated that subjects believed these movements to be less animate than those of the human stimuli but the visuomotor priming effects of the human and robotic stimuli did not differ. In the second experiment, when the robotic stimuli were more angular and symmetrical than the human stimuli, human movements elicited more visuomotor priming than the robotic movements. However, the subjects’ beliefs about the animacy of the stimuli did not affect their performance. These results suggest that bottom-up processing is primarily responsible for the visuomotor priming advantage of human stimuli.

Thromboxane A2 inhibition of SKCa after NO synthase block in rat middle cerebral artery

NO/prostanoid independent, EDHF-mediated hyperpolarization and dilation in rat middle cerebral arteries is mediated solely by endothelial cell IK(Ca). However, when the NO-pathway is also active, both SK(Ca) and IK(Ca) contribute to EDHF responses. As the SK(Ca) component can be inhibited by stimulation of thromboxane A(2) (TxA(2)) TP receptors and NO has the potential ability to inhibit thromboxane synthesis, we investigated whether TxA(2) might explain loss of functional input from SK(Ca) during NOS inhibition in cerebral arteries. EXPERIMENTAL APPROACH: Rat middle cerebral arteries were mounted in a wire myograph. Endothelium-dependent responses to the PAR2 agonist, SLIGRL were assessed as simultaneous changes in smooth muscle membrane potential and tension. KEY RESULTS: Responses were obtained in the presence of L-NAME as appropriate. Inhibition of TP receptors with either ICI 192,605 or SQ 29,548, did not affect EDHF mediated hyperpolarization and relaxation, but in their presence neither TRAM-34 nor apamin (to block IK(Ca) and SK(Ca) respectively) individually affected the EDHF response. However, in combination they virtually abolished it. Similar effects were obtained in the presence of the thromboxane synthase inhibitor, furegrelate, which additionally revealed an iberiotoxin-sensitive residual EDHF hyperpolarization and relaxation in the combined presence of TRAM-34 and apamin. CONCLUSIONS AND IMPLICATIONS: In the rat middle cerebral artery, inhibition of NOS leads to a loss of the SK(Ca) component of EDHF responses. Either antagonism of TP receptors or block of thromboxane synthase restores an input through SK(Ca). These data indicate that NO normally enables SK(Ca) activity in rat middle cerebral arteries.

Evidence for involvement of both IKCa and SKCa channels in hyperpolarizing responses of the rat middle cerebral artery

Endothelium-derived hyperpolarizing factor responses in the rat middle cerebral artery are blocked by inhibiting IKCa channels alone, contrasting with peripheral vessels where block of both IKCa and SKCa is required. As the contribution of IKCa and SKCa to endothelium-dependent hyperpolarization differs in peripheral arteries, depending on the level of arterial constriction, we investigated the possibility that SKCa might contribute to equivalent hyperpolarization in cerebral arteries under certain conditions. METHODS: Rat middle cerebral arteries (approximately 175 microm) were mounted in a wire myograph. The effect of KCa channel blockers on endothelium-dependent responses to the protease-activated receptor 2 agonist, SLIGRL (20 micromol/L), were then assessed as simultaneous changes in tension and membrane potential. These data were correlated with the distribution of arterial KCa channels revealed with immunohistochemistry. RESULTS: SLIGRL hyperpolarized and relaxed cerebral arteries undergoing variable levels of stretch-induced tone. The relaxation was unaffected by specific inhibitors of IKCa (TRAM-34, 1 micromol/L) or SKCa (apamin, 50 nmol/L) alone or in combination. In contrast, the associated smooth-muscle hyperpolarization was inhibited, but only with these blockers in combination. Blocking nitric oxide synthase (NOS) or guanylyl cyclase evoked smooth-muscle depolarization and constriction, with both hyperpolarization and relaxation to SLIGRL being abolished by TRAM-34 alone, whereas apamin had no effect. Immunolabeling showed SKCa and IKCa within the endothelium. CONCLUSIONS: In the absence of NO, IKCa underpins endothelium-dependent hyperpolarization and relaxation in cerebral arteries. However, when NOS is active SKCa contributes to hyperpolarization, whatever the extent of background contraction. These changes may have relevance in vascular disease states where NO release is compromised and when the levels of SKCa expression may be altered.

Endosomal proteolysis regulates calcitonin gene-related peptide responses in mesenteric arteries

Background and Purpose: Calcitonin gene‐related peptide (CGRP) is a potent vasodilator, implicated in the pathogenesis of migraine. CGRP activates a receptor complex comprising, calcitonin receptor‐like receptor (CLR) and receptor activity‐modifying protein 1 (RAMP1). In vitro studies indicate recycling of CLR•RAMP1 is regulated by degradation of CGRP in early endosomes by endothelin‐converting enzyme‐1 (ECE‐1). However, it is not known if ECE‐1 regulates the resensitization of CGRP‐induced responses in functional arterial tissue. Experimental Approach: CLR, ECE‐1a‐d and RAMP1 expression in rat mesenteric artery smooth muscle cells (RMA‐SMCs) and mesenteric arteries was analyzed by RT‐PCR and by immunofluorescence and confocal microscopy. CGRP‐induced signaling in cells was examined by measuring cAMP production and ERK activation. CGRP‐induced relaxation of arteries was measured by isometric wire myography. ECE‐1 was inhibited using the specific inhibitor, SM‐19712. Key Results: RMA‐SMCs and arteries contained mRNA for CLR, ECE‐1a‐d and RAMP1. ECE‐1 was present in early endosomes of RMA‐SMCs and in the smooth muscle layer of arteries. CGRP induced endothelium‐independent relaxation of arteries. ECE‐1 inhibition had no effect on initial CGRP‐induced responses but reduced cAMP generation in RMA‐SMCs and vasodilation in mesenteric arteries responses to subsequent CGRP challenges. Conclusions and Implications: ECE‐1 regulates the resensitization of responses to CGRP in RMA‐SMCs and mesenteric arteries. CGRP‐induced relaxation does not involve endothelium‐derived pathways. This is the first report of ECE‐1 regulating CGRP responses in SMCs and arteries. ECE‐1 inhibitors may attenuate an important vasodilatory pathway, implicated in primary headaches and may represent a new therapeutic approach for the treatment of migraine.

Possible role for K+ in endothelium-derived hyperpolarizing factor–linked dilatation in rat middle cerebral artery

Background and Purpose— Endothelium-derived hyperpolarizing factor (EDHF) and K+ are vasodilators in the cerebral circulation. Recently, K+ has been suggested to contribute to EDHF-mediated responses in peripheral vessels. The EDHF response to the protease-activated receptor 2 ligand SLIGRL was characterized in cerebral arteries and used to assess whether K+ contributes as an EDHF. Methods— Rat middle cerebral arteries were mounted in either a wire or pressure myograph. Concentration-response curves to SLIGRL and K+ were constructed in the presence and absence of a variety of blocking agents. In some experiments, changes in tension and smooth muscle cell membrane potential were recorded simultaneously. Results— SLIGRL (0.02 to 20 μmol/L) stimulated concentration and endothelium-dependent relaxation. In the presence of NG-nitro-L-arginine methyl ester, relaxation to SLIGRL was associated with hyperpolarization and sensitivity to a specific inhibitor of IKCa, 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (1μmol/L), reflecting activation of EDHF. Combined inhibition of KIR with Ba2+ (30μmol/L) and Na+/K+-ATPase with ouabain (1 μmol/L) markedly attenuated the relaxation to EDHF. Raising extracellular [K+] to 15 mmol/L also stimulated smooth muscle relaxation and hyperpolarization, which was also attenuated by combined application of Ba2+ and ouabain. Conclusions— SLIGRL evokes EDHF-mediated relaxation in the rat middle cerebral artery, underpinned by hyperpolarization of the smooth muscle. The profile of blockade of EDHF-mediated hyperpolarization and relaxation supports a pivotal role for IKCa channels. Furthermore, similar inhibition of responses to EDHF and exogenous K+ with Ba2+ and ouabain suggests that K+ may contribute as an EDHF in the middle cerebral artery.

Statins and selective inhibition of Rho kinase protect small conductance calcium-activated potassium channel function (KCa2.3) in cerebral arteries

Background: In rat middle cerebral and mesenteric arteries the KCa2.3 component of endothelium-dependent hyperpolarization (EDH) is lost following stimulation of thromboxane (TP) receptors, an effect that may contribute to the endothelial dysfunction associated with cardiovascular disease. In cerebral arteries, KCa2.3 loss is associated with NO synthase inhibition, but is restored if TP receptors are blocked. The Rho/Rho kinase pathway is central for TP signalling and statins indirectly inhibit this pathway. The possibility that Rho kinase inhibition and statins sustain KCa2.3 hyperpolarization was investigated in rat middle cerebral arteries (MCA). Methods: MCAs were mounted in a wire myograph. The PAR2 agonist, SLIGRL was used to stimulate EDH responses, assessed by simultaneous measurement of smooth muscle membrane potential and tension. TP expression was assessed with rt-PCR and immunofluorescence. Results: Immunofluorescence detected TP in the endothelial cell layer of MCA. Vasoconstriction to the TP agonist, U46619 was reduced by Rho kinase inhibition. TP receptor stimulation lead to loss of KCa2.3 mediated hyperpolarization, an effect that was reversed by Rho kinase inhibitors or simvastatin. KCa2.3 activity was lost in L-NAME-treated arteries, but was restored by Rho kinase inhibition or statin treatment. The restorative effect of simvastatin was blocked after incubation with geranylgeranyl-pyrophosphate to circumvent loss of isoprenylation. Conclusions: Rho/Rho kinase signalling following TP stimulation and L-NAME regulates endothelial cell KCa2.3 function. The ability of statins to prevent isoprenylation and perhaps inhibit of Rho restores/protects the input of KCa2.3 to EDH in the MCA, and represents a beneficial pleiotropic effect of statin treatment.