Geometrically Constrained Skyrmions

Skyrmions are chiral swirling magnetization structures with nanoscale size. These structures have attracted considerable attention due to their topological stability and promising applicability in nanodevices, since they can be displaced with spin-polarized currents. However, for the comprehensive implementation of skyrmions in devices, it is imperative to also attain control over their geometrical position. Here we show that, through thickness modulations introduced in the host material, it is possible to constrain three-dimensional skyrmions to desired regions. We investigate skyrmion structures in rectangular FeGe platelets with micromagnetic finite element simulations. First, we establish a phase diagram of the minimum-energy magnetic state as a function of the external magnetic field strength and the film thickness. Using this understanding, we generate preferential sites for skyrmions in the material by introducing dot-like “pockets” of reduced film thickness. We show that these pockets can serve as pinning centers for the skyrmions, thus making it possible to obtain a geometric control of the skyrmion position. This control allows for stabilization of skyrmions at positions and in configurations that they would otherwise not attain. Our findings may have implications for technological applications in which skyrmions are used as units of information that are displaced along racetrack-type shift register devices.

Plantar Mechanical Stimulation Maintains Slow Myosin Expression in Disused Rat Soleus Muscle via NO-Dependent Signaling

It was observed that gravitational unloading during space missions and simulated microgravity in ground-based studies leads to both transformation of slow-twitch muscle fibers into fast-twitch fibers and to the elimination of support afferentation, leading to the “switching-off” of postural muscle motor units electrical activity. In recent years, plantar mechanical stimulation (PMS) has been found to maintain the neuromuscular activity of the hindlimb muscles. Nitric oxide (NO) was shown to be one of the mediators of muscle fiber activity, which can also promote slow-type myosin expression. We hypothesized that applying PMS during rat hindlimb unloading would lead to NO production upregulation and prevention of the unloading-induced slow-to-fast fiber-type shift in rat soleus muscles. To test this hypothesis, Wistar rats were hindlimb suspended and subjected to daily PMS, and one group of PMS-subjected animals was also treated with nitric oxide synthase inhibitor (L-NAME). We discovered that PMS led to sustained NO level in soleus muscles of the suspended animals, and NOS inhibitor administration blocked this effect, as well as the positive effects of PMS on myosin I and IIa mRNA transcription and slow-to-fast fiber-type ratio during rat hindlimb unloading. The results of the study indicate that NOS activity is necessary for the PMS-mediated prevention of slow-to-fast fiber-type shift and myosin I and IIa mRNA transcription decreases during rat hindlimb unloading.

Evento Coacción de la Construcción ¨Nombre + posposición temporal¨ en chino y estudio comparativo con el español: una perspectiva de la Estructura de Qualia extendida

El presente trabajo, basado en la Teoría del Lexicón generativo (TLG) (Pustejovsky, 1995), procura aportar una interpretación detallada y profunda de los fenómenos del Tipo Discordancia (Type Mismatch) y el Tipo Transición (Type shift) en la construcción ¨Nombre + Posposición temporal¨. Para ello, se realizará un análisis de los casos más representativos, en este caso, las posposiciones temporales后hou/之后zhihou/以后yihou(HOU). Se tomarán a su vez como referencia, sus equivalentes en español, como es el conector adverbial temporal después de (Vanderschueren 2013), con el fin de indagar cómo opera el mecanismo generativo semántico Evento coacción en chino. La construcción canónica (Chomsky 1986) ¨Nombre + posposición temporal¨ tiene la función de localizar un evento dentro de un eje temporal, donde se requiere que el complemento sea un sustantivo del tiempo, como: un punto de tiempo (el momento del evento), un punto de tiempo de referencia (el momento de referencia), o bien, un punto de tiempo de la enunciación (el momento de la enunciación). Cuando en la posición del complemento se presenta un nombre eventivo o no eventivo, la posposición temporal exigirá que dicho nombre sea o se convierta en un delimitado, del cual se pueda derivar un punto en el tiempo. En tal proceso del tipo transición, el nombre eventivo atípico estará coaccionado por su determinante, y pasará de nombre eventivo no delimitado a delimitado. El nombre no eventivo, está directamente coaccionado por la posposición temporal, y pasará de nombre no eventivo, a eventivo delimitado, para satisfacer el requisito de las posposiciones temporales como Hou. Sin embargo, no todos los nombres no eventivos pueden usarse en la construcción coaccionada ¨Nombre + posposición temporal¨. Solamente los nombres secuenciales (Ma 1991) pueden aparecer en la posición del complemento en dicha construcción, gracias a que, el rasgo sub-léxico [Temporalidad contextual] ([TC]) (Liu 2004) les posibilita a obtener la interpretación eventiva. Finalmente, el presente estudio deduce una formal lógica del proceso sintáctico en chino, en el que funciona la coerción de tipos. Dicha lógica forma favorecería una perspectiva dinámica de las relaciones léxicas entre los diferentes tipos de nombres y posposiciones temporales, y a su vez, permite ver claramente las etapas en las cuáles se ha experimentado el Tipo Transición. Los resultados permiten observar, que la propuesta de la TLG puede explicar cómo opera el mecanismo generativo Evento coacción en la construcción ¨Nombre + posposición temporal¨, no obstante, es necesario ampliar la perspectiva del análisis de la Estructura Qualia (EQ) a la Estructura Qualia Extentida (EQE) (Yuan 2014).

The effect of commodity prices on voting for the left and the right in Brazil

How do economic shocks impact electoral outcomes? I bring novel evidence to this debate by analyzing how a sharp drop in commodity prices that begun in 2011 affected Brazilian political behavior and public opinion. I do so by computing the exposure of Brazilian municipalities to this sharp drop in commodity prices with a Bartik-type shift-share instrument. I conclude that in municipalities more exposed to a negative commodity shock, right-wing parties had an advantage in the 2018 presidential election, while left-wing parties lost support. By linking Manifesto Project scores with electoral data, I show that the parties that were benefited from this sharp drop in commodity prices had a liberal economic agenda and a conservative and authoritarian non-economic platform. Using survey data, I provide evidence that the shock has an effect on conservative and authoritarian attitudes, but not on anti-establishment and anti-incument attitudes.

Orbit Growth of Periodic-Finite-Type Shifts via Artin–Mazur Zeta Function

The prime orbit and Mertens’ orbit counting functions describe the growth of closed orbits in a discrete dynamical system in a certain way. In this paper, we prove the asymptotic behavior of these functions for a periodic-finite-type shift. The proof relies on the meromorphic extension of its Artin–Mazur zeta function.

Carica papaya: Potential Implications in Human Health

Background: Carica papaya, a tree-like herb, is cultivated in more than 50 tropical and subtropical countries worldwide. The parts [leaves, fruit (ripe and unripe), seeds and latex] are used as food as well as traditional medicine in several ways for a number of diseases. Papaya, with a variety of phytochemicals like carotenoids, polyphenols, benzyl isothiocynates, benzyl glucosinates, prunasin (cyanogenic substrate), papain and chymopapain, alkaloids, phenolic compounds, flavonoids, vitamins (A, C, E), carotenoids, cyanogenicglucosides, cystatin, and glucosinolates exhibits significant health benefits ranging from digestive to immune modulation. These compounds have antioxidant, chemoprotective, anti-diabetic, anti-bacterial, anti-plasmodial and anti-fungal activities. Papaya aqueous leaf extract was evaluated for immunomodulatory and anti-tumor activities through cytokine modulation with Th1 type shift in human immune system through molecular studies. The platelet augmenting potential of aqueous leaf extract has been reported in numerous clinical studies and deserves special mention. Objective: The scientific knowledge of carica papaya in the post-genomic era including molecular studies and clinical trials is discussed in the review. Methods: The published literature on botany, chemical composition, ethnopharmacology, and uses of papaya in food and medical industry was searched through databases like Pub- Med, Scopus, and Google scholar to comprehend the benefits of Carica papaya for human use with around more than 600 published peer- reviewed papers. Results: Many traditional and novel uses of Carica papaya for the human benefit are detailed in the review that significantly adds to the scientific knowledge of curious readers. Conclusion: Each component of the papaya plant is rich in phytochemicals and is economically important. Most of the phytochemicals are linked to biological functions and influence a variety of cellular processes; hence they have implications in refining human health.