Business organizations in their work environment, aspire to create a high level of performance and low levels of absenteeism and turnover. Organizational commitment is considered a key factor in achieving this objective, however, it can be conditioned by several factors, among which is the psychological contract. The literature has related the organizational commitment with the fulfillment of the psychological contract framing it as one of the explanatory variables. This work aims to investigate research trends on psychological contract and organizational commitment. (...) For this purpose, bibliometric techniques and the software SciMAT have been used. 220 journal articles indexed in Web of Science (WoS) were analyzed. The findings indicate that the theme chosen for this review is valid. Based on the relationship between the two concepts, as the most recurrent themes, issues such as the sense of justice and the consequences of the violation of the psychological contract, normative commitment, HR management or job insecurity are addressed. However, in the last period analyzed (2015–2018), publications related to more sensitive topics to the present time emerge, such as the employability or the impact of these two concepts in the new generations (millennial and generation-Y) or the retention of talent. On the other hand, shortcomings are detected in the research on the ideologically charged psychological contract, the analysis of the organizational context or cultural and demographic factors in relation to both theoretical constructs. The contribution of this work lies in giving visibility to scientific results, which will serve business organizations as instruments for decision making in their labor management and, for the scientific community, as knowledge of the research spaces to explore. (shrink)

The guerrilla led by Fidel Castro and the political implications of his triumph in 1959 constitute a widely researched object of study. This text seeks to offer a reading of US responses through the construction of a geopolitical code, which aims to neutralise the revolutionary inspiration produced by the Cuban example in Latin America. The analysis draws on a series of primary sources to highlight the political, economic and diplomatic strands that shape White House foreign policy not only towards Cuba, (...) but also towards the whole of the region. (shrink)

La figura de José Carlos Mariátegui es una referencia intelectual en el pensamiento revolucionario latinoamericano. Su producción intelectual está acompañada de un compromiso político con las ideas transformadoras aplicadas al conjunto de América Latina y, de manera especial, a Perú. Sus aportaciones teóricas y sus propuestas prácticas para organizar a la clase obrera del país andino son motivo de disputa ideológica en el seno del comunismo peruano durante las décadas centrales del siglo XX. En ese ambiente surge Sendero Luminoso, una (...) organización dispuesta a impulsar el proceso revolucionario por la vía armada. Este texto busca los anclajes de su ideario a partir de los planteamientos iniciales sugeridos por el autor de Siete ensayos de interpretación de la realidad peruana. (shrink)

En el presente trabajo vamos a otear el paisaje de la fatalidad que, sin duda, representan los escritos de Cioran, con el objetivo de analizar si es posible una solución afirmativa, al estilo de la música y el arte en Schopenhauer o el vitalismo de Simmel, a la esencia problemática de la existencia humana, lo que significa tratar de dilucidar acerca de si es posible la liberación del sufrimiento en el sujeto o, en caso de no serlo, ver en qué (...) medida podemos mitigar el dolor adoptando otro tipo de filosofías de orden terapéutico frente a otro tipo de filo-sofías de carácter pesimista que abogan por la negación de la vida como es el caso de la filosofía de la redención de Mainländer. (shrink)

Previous studies on body ownership illusions have shown that under certain multimodal conditions, healthy people can experience artificial body-parts as if they were part of their own body, with direct physiological consequences for the real limb that gets ‘substituted’. In this study we wanted to assess (a) whether healthy people can experience ‘missing’ a body-part through illusory ownership of an amputated virtual body, and (b) whether this would cause corticospinal excitability changes in muscles associated with the ‘missing’ body-part. Forty right-handed (...) participants saw a virtual body from a first person perspective but for half of them the virtual body was missing a part of its right arm. Single pulse transcranial magnetic stimulation was applied before and after the experiment to left and right motor cortices. Motor evoked potentials (MEPs) were recorded from the first dorsal interosseous (FDI) and the extensor digitorum communis (EDC) of each hand. We found that the stronger the illusion of amputation and arm ownership, the more the reduction of MEP amplitudes of the EDC muscle for the contralateral sensorimotor cortex. In contrast, no association was found for the EDC amplitudes in the ipsilateral cortex and for the FDI amplitudes in both contralateral and ipsilateral cortices. Our study provides evidence that a short-term illusory perception of missing a body-part can trigger inhibitory effects on corticospinal pathways and importantly in the absence of any limb deafferentation or disuse. (shrink)

Todos los Acuerdos de Libre Comercio (ALCs) concluidos recientemente por la Unión Europea (UE) incluyen capítulos sobre Comercio y Desarrollo Sostenible (CDS) donde se recogen compromisos mutuos en materia laboral y medioambiental. Las disposiciones sobre medio ambiente mencionan expresamente los acuerdos multilaterales que cada Parte se compromete a cumplir, como el Acuerdo de París sobre cambio climático. Sin embargo, la falta de un mecanismo de ejecución efectiva en caso de incumplimiento de las disposiciones sobre CDS merma la credibilidad de los (...) compromisos de sostenibilidad. El ALC de la UE con Nueva Zelanda representa un punto de inflexión en esta tendencia, ya que introduce un nuevo modelo de aplicación. Con respecto a los compromisos climáticos, en particular, el ACL incluye objetivos ambiciosos que, unido al nuevo enfoque de aplicación, podrían incorporarse a futuros ALCs de la UE, contribuyendo así de forma importante a la lucha global contra el cambio climático. (shrink)

Although it is commonly believed that the concept of brain death was developed to benefit organ transplants, it evolved independently. Transplantation owed its development to advances in surgery and immunosuppressive treatment; BD owed its origin to the development of intensive care. The first autotransplant was achieved in the early 1900s, when studies of increased intracranial pressure causing respiratory arrest with preserved heartbeat were reported. Between 1902 and 1950, the BD concept was supported by the discovery of EEG, Crile’s definition of (...) death, the use of EEG to demonstrate abolition of brain potentials after ischaemia, and Crafoord’s statement that death was due to cessation of blood flow. Transplantation saw the first xenotransplant in humans and the first unsuccessful kidney transplant from a cadaver. In the 1950s, circulatory arrest in coma was identified by angiography, and the death of the nervous system and coma dépassé were described. Murray performed the first successful kidney transplant. In the 1960s, the BD concept and organ transplants were instantly linked when the first kidney transplant using a brain-dead donor was performed; Schwab proposed to use EEG in BD; the Harvard Committee report and the Sydney Declaration appeared; the first successful kidney, lung and pancreas transplants using cadaveric donors were achieved; Barnard performed the first human heart transplant. This historical review demonstrates that the BD concept and organ transplantation arose separately and advanced in parallel, and only began to progress together in the late 1960s. Therefore, the BD concept did not evolve to benefit transplantation. (shrink)

The present paper reveals (non-relativistic) quantum mechanics as an emergent property of otherwise classical ergodic systems embedded in a stochastic vacuum or zero-point radiation field (zpf). This result provides a theoretical basis for understanding recent numerical experiments in which a statistical analysis of an atomic electron interacting with the zpf furnishes the quantum distribution for the ground state of the H atom. The action of the zpf on matter is essential within the present approach, but it is the ergodic demand (...) what ultimately leads to the matrix formulation of quantum mechanics. The paper thus represents a step forward in the quest for an elucidation of the fundamentals of quantum mechanics. (shrink)

We discuss the main results of Linear Stochastic Electrodynamics, starting from a reformulation of its basic assumptions. This theory shares with Stochastic Electrodynamics the core assumption that quantization comes about from the permanent interaction between matter and the vacuum radiation field, but it departs from it when it comes to considering the effect that this interaction has on the statistical properties of the nearby field. In the transition to the quantum regime, correlations between field modes of well-defined characteristic frequencies arise, (...) which coincide with the transition frequencies of quantum mechanics and are therefore directly related with the energy quantization. The Heisenberg equations of motion of (non-relativistic) quantum electrodynamics are thus obtained. After a detailed consideration of the significance of the approximations made, we present a discussion on some of the most delicate or controversial features of quantum mechanics from the perspective provided by the present theory. (shrink)

We formulate from first principles a theory of stochastic processes in configuration space. The fundamental equations of the theory are an equation of motion which generalizes Newton's second law and an equation which expresses the condition of conservation of matter. Two types of stochastic motion are possible, both described by the same general equations, but leading in one case to classical Brownian motion behavior and in the other to quantum mechanical behavior. The Schrödinger equation, which is derived here with no (...) further assumption, is thus shown to describe a specific stochastic process. It is explicitly shown that only in the quantum mechanical process does the superposition of probability amplitudes give rise to interference phenomena; moreover, the presence of dissipative forces in the Brownian motion equations invalidates the superposition principle. At no point are any special assumptions made concerning the physical nature of the underlying stochastic medium, although some suggestions are discussed in the last section. (shrink)

An analysis is briefly presented of the possible causes of the failure of stochastic electrodynamics (SED) when applied to systems with nonlinear forces, on the basis that the main principles of the theory are correct. In light of this analysis, an alternative approach to the theory is discussed, whose postulates allow to establish contact with quantum mechanics in a natural way. The ensuing theory, linear SED, confirms the essential role of the vacuum–particle interaction as the source of quantum phenomena.

ObjectiveTo investigate the association of pre-existing migraine in patients hospitalised and who recovered from severe acute respiratory syndrome coronavirus 2 infection with the presence of post-coronavirus disease symptoms.BackgroundNo study has investigated the role of migraine as a risk factor for development of post-COVID symptoms.MethodsA case-control study including individuals hospitalised during the first wave of the pandemic was conducted. Patients with confirmed previous diagnosis of migraine were considered cases. Two age- and sex-matched individuals without a history of headache per case were (...) also recruited as controls. Hospitalisation/clinical data were collected from hospital medical records. Patients were scheduled for a telephone interview. A list of post-COVID symptoms was systematically evaluated, but participants were invited to freely report any symptom. The Hospital Anxiety and Depression Scale and the Pittsburgh Sleep Quality Index were used to assess anxiety/depressive symptoms and sleep quality. Multivariable conditional logistic regression models were constructed.ResultsOverall, 57 patients with confirmed diagnosis of migraine and 144 non-migraine controls who had recovered from COVID-19 were assessed at 7.3 months after hospital discharge. The number of post-COVID symptoms in the migraine group was significantly greater than in the non-migraine group. Fatigue was significantly more prevalent in the migraine group. However, no between-groups difference in the prevalence of headache as a post-COVID symptom was detected.ConclusionPatients with a history of migraine who recovered from COVID-19 exhibited more long-term fatigue as post-COVID sequelae than those without migraine. Some of the pathophysiological changes associated with migraine could predispose to the occurrence of post-COVID symptoms. (shrink)

The blackbody radiation field is studied from different points of view. The existence of zero-point fluctuations is shown to be crucial in determining the form of the thermal part of the spectrum. The notion of a continuous field is seen to be compatible with a discrete structure for its interaction: The description normally used in the quantum context does not refer to the field but to its interaction with atomic systems, which involves statistically independent elementary acts of absorption and emission. (...) The same classical field has different effects on absorption and on emission, and these are conveniently, but not necessarily, described in terms of non-commuting operators. (shrink)

The connection between stochastic electrodynamics (SED) and the quantum theory of matter is further explored. The main result is that the Fokker-Planck-like equation of SED can be recast into the form of a Schrödinger equation with radiative corrections, when the system is close to a state of equilibrium. The phase-space distribution can be written as Wigner's pseudo-distribution plus corrections due to the nonlinearity of the external force and to radiative effects. The radiative corrections predicted by the theory, namely the Lamb (...) shift and the decay of excited atomic states, coincide with those predicted by QED. Moreover, the theory offers a clear physical interpretation of these phenomena as due to the coupling of the electric dipole of the system with the zero-point radiation field and to radiation reaction, respectively. (shrink)

By making use of the method of moments we study some aspects of the statistical behavior of the nonrelativistic harmonic oscillator according to stochastic electrodynamics. We show that the random rotations induced on the particle by the zero-point field account for the magnitude of the spin of the electron, the result differing from the correct one(3/4)h 2 by a factor of2. Assuming that the measurement of a spin projection may be effectively taken into account by considering the action of only (...) the subensemble of the field with the corresponding circular polarization, the calculated value of the spin projection comes out to be the correct one within a factor of order unity. The radiative corrections give rise to both the Lamb shift and the anomalous magnetic moment of the electron, the latter being evaluated to within a factor of2. The magnetic and gyromagnetic properties of the electron come out to be in agreement with quantum mechanics. Interference effects are shown to occur when evaluating the average value of the square of the angular momentum. (shrink)

The origin of the wave properties of matter is discussed from the point of view of stochastic electrodynamics. A nonrelativistic model of a charged particle with an effective structure embedded in the random zeropoint radiation field reveals that the field induces a high-frequency vibration on the particle; internal consistency of the theory fixes the frequency of this jittering at mc2/ħ. The particle is therefore assumed to interact intensely with stationary zeropoint waves of this frequency as seen from its proper frame (...) of reference; such waves, identified here as de Broglie's phase waves, give rise to a modulated wave in the laboratory frame, with de Broglie's wavelength and phase velocity equal to the particle velocity. The time-independent equation that describes this modulated wave is shown to be the stationary Schrödinger equation (or the Klein-Gordon equation in the relativistic version). In a heuristic analysis appled to simple periodic cases, the quantization rules are recovered from the assumption that for a particle in a stationary state there must correspond a stationary modulation.Along an independent and complementary line of reasoning, an equation for the probability amplitude in configuration space for a particle under a general potential V(x) is constructed, and it is shown that under conditions derived from stochastic electrodynamics it reduces to Schrödinger's equation. This equation reflects therefore the dual nature of the quantum particles, by describing simultaneously the corresponding modulated waveand the ensemble of particles. (shrink)

The numerical study of a glycolytic model formed by a system of three delay differential equations reveals a multiplicity of stable coexisting states: birhythmicity, trirhythmicity, hard excitation and quasiperiodic with chaotic regimes. For different initial functions in the phase space one may observe the coexistence of two different quasiperiodic motions, the existence of a stable steady state with a stable torus, and the existence of a strange attractor with different stable regimes (chaos with torus, chaos with bursting motion, and chaos (...) with different periodic regimes). For a single range of the control parameter values our system may exhibit different bifurcation diagrams: in one case a Feigenbaum route to chaos coexists with a finite number of successive periodic bifurcations, in other conditions it is possible to observe the coexistence of two quasiperiodicity routes to chaos. These studies were obtained both at constant input flux and under forcing conditions. (shrink)

Arguments are given in favor of a stochastic theory of quantum mechanics, clearly distinguishable from Brownian motion theory. A brief exposition of the phenomenological theory of stochastic quantum mechanics is presented, followed by a list of its main results and perspectives. A possible answer to the question about the origin of stochasticity is given in stochastic electrodynamics by assigning a real character to the vacuum radiation field. This theory is shown to reproduce important quantum mechanical results, some of which are (...) presented explicitly to illustrate its potentialities. Finally the main problems and some perspectives of research within stochastic electrodynamics are discussed. (shrink)

The nm23 gene, a putative metastasis suppressor gene, was originally identified by its reduced expression in highly metastatic K‐1735 murine melanoma cell lines, as compared to related, low metastatic melanoma cell lines. Transfection of nm23 cDNA has been reported to suppress malignant progression in Drosophila and mammalian cells. Highly conserved homologues of nm23 have been found in organisms ranging from the prokaryote Myxococcus xanthus to Drosophila, where the gene is involved in normal development and differentiation. The product of the nm23 (...) gene exhibits a nucleoside diphosphate kinase activity, yet the nucleoside diphosphate kinase activity of Nm23 does not correlate with its apparent biological functions. We review recent cellular, genetic, biochemical and X‐ray crystallographic data to formulate and evaluate hypotheses concerning the molecular mechanism of nm23 action. (shrink)

Validated self-report measures of post-stroke fatigue are lacking. The Dutch Multifactor Fatigue Scale (DMFS) was translated into Danish, and response process evidence of validity was evaluated. DMFS consists of 38 Likert-rated items distributed on five subscales: Impact of fatigue (11 items), Signs and direct consequences of fatigue (9), Mental fatigue (7), Physical fatigue (6), and Coping with fatigue (5). Response processes to DMFS were investigated using a Three-Step Test-Interview (TSTI) protocol, and data were analyzed using Framework Analysis. Response processes were (...) indexed on the following categories: (i) “congruent,” response processes were related to the subscale construct; (ii) “incongruent,” response processes were not related to the subscale construct; (iii) “ambiguous,” response processes were both congruent and incongruent or insufficient to evaluate congruency; and (iv) “confused,” participants did not understand the item. Nine adults were recruited consecutively 10–34 months post-stroke (median = 26.5) at an outpatient brain injury rehabilitation center in 2019 [five females, mean age = 55 years (SD= 6.3)]. Problematic items were defined as <50% of response processes being congruent with the intended construct. Of the 38 items, five problematic items were identified, including four items of Physical fatigue and one of Mental fatigue. In addition, seven items posed various response difficulties to some participants due to syntactic complexity, vague terms, a presupposition, and a double-barrelled statement. In conclusion, findings elucidate the interpretative processes involved in responding to DMFS post-stroke, strengthen the evidence base of validity, and guide revisions to mitigate potential problems in item performance. (shrink)

This paper analyses the way in which discourse and argumentation may vary depending on participants’ educational level and gender. Men and women from three different educational levels (literacy, advanced level and university students) participated in discussion groups that debated about women and work, the sharing of housework and the way in which girls and boys are educated. The results showed important differences depending on participants’ educational level and gender. In general, the main differences were related to educational level, while gender (...) tended to interact with educational level, as a moderating factor. (shrink)

This paper deals with an (otherwise classical) two-(non-interacting) particle system immersed in a common stochastic zero-point radiation field. The treatment is an extension of the one-particle case for which it has been shown that the quantum properties of the particle emerge from its interaction with the background field under stationary and ergodic conditions. In the present case we show that non-classical correlations—describable only in terms of entanglement—arise between the (nearby) particles whenever both of them resonate to a common frequency of (...) the field. For identical particles the entanglement becomes maximum and must be described by totally (anti)symmetric states. (shrink)