Formation and fate of the born-again planetary nebula HuBi 1

We present the first 3D radiation-hydrodynamic simulations on the formation and evolution of born-again planetary nebulae (PNe), with particular emphasis to the case of HuBi1, the inside-out PN. We use the extensively-tested GUACHO code to simulate the formation of HuBi1 adopting mass-loss and stellar wind terminal velocity estimates obtained from observations presented by our group. We found that, if the inner shell of HuBi1 was formed by an explosive very late thermal pulse (VLTP) ejecting material with velocities of $\sim$300 km s$^{-1}$, the age of this structure is consistent with that of $\simeq$200 yr derived from multi-epoch narrow-band imaging. Our simulations predict that, as a consequence of the dramatic reduction of the stellar wind velocity and photon ionizing flux during the VLTP, the velocity and pressure structure of the outer H-rich nebula are affected creating turbulent ionized structures surrounding the inner shell. These are indeed detected in Gran Telescopio Canarias MEGARA optical observations. Furthermore, we demonstrate that the current relatively low ionizing photon flux from the central star of HuBi1 is not able to completely ionize the inner shell, which favors previous suggestions that its excitation is dominated by shocks. Our simulations suggest that the kinetic energy of the H-poor ejecta of HuBi1 is at least 30 times that of the clumps and filaments in the evolved born-again PNe A30 and A78, making it a truly unique VLTP event.Comment: 9 pages, 10 figures, no tables; accepted to MNRA

Testosterona y evaluación de la conducta agresiva en jóvenes judokas

En un grupo de jóvenes judokas (15 a 22 años), se analizan las relaciones entre los andrógenos y la conducta agresiva evaluada por dos instrumentos: un autoinforme y un cuestionario cumplimentado por los entrenadores, que presenta correlaciones más consistentes con los valores hormonales. En la muestra estudiada, las relaciones entre hormonas y conducta agresiva son más evidentes entre los sujetos de mayor edad que entre los adolescentes. Este aumento de la conducta agresiva está significativamente relacionado con la edad y con los años de práctica del Judo. Los sujetos de alto nivel competitivo obtienen puntuaciones significativamente mayores que los de nivel más bajo, sugiriendo la influencia de la actividad competitiva sobre la conducta agresivaRelationships between androgenic hormones and aggressive behavior are analysed in young judoists (15-22 years). Aggressive behavior has been assessed by two means: a self-report inventory and a scale answered by the subjects' coaches. This scale shows more consistent correlations with hormonal values. In our subjects, these relations are stronger in older than in younger subjects. The increase in aggressive behavior is significantly related to the age and also to the time of judo practice. High-level competitors obtain significantly higher scores than low-level subjects, suggesting the influence of competition on aggressive behavio

Novo neonicotinóide associado a regulador de crescimento de insetos, no controle da mosca-branca e do pulgão na cultura do algodão.

Resumo: O objetivo deste trabalho foi avaliar o desempenho da nova molécula química dinotefuram, pertencente ao grupo dos neonicotinóides, associada a um análogo do hormônio juvenil (piriproxifem), em aplicação foliar, no controle da mosca-branca B. tabaci Biótipo B e do pulgão A. gossypii, em algodoeiro. O delineamento foi em blocos ao acaso com quatro repetições. Os tratamentos foram: testemunha, dinotefuram + piriproxifem a 25 + 12,5; 50 + 12,5; 75 + 12,5; 25 + 25; 50 + 25; 75 + 25 e dinotefuram a 75 g i.a./ha. Cada parcela foi de 48m2. Para aplicação foliar, utilizou-se um pulverizador costal equipado com barra contendo seis pontas cônicas (TXVK-8), propelido por CO2 e volume de 200 L/ha. Foram realizadas avaliações de eficiência dos tratamentos aos 0, 5, 10, 15 e 20 dias após a aplicação, contando-se o número de ninfas de mosca-branca e o número de pulgões em 10 folhas por parcela. Pela análise dos resultados, concluiu-se que o inseticida dinotefuram associado ao piriproxifem, foi eficiente no controle de ninfas de mosca-branca e do pulgão, igualando-se aos padrões já utilizados

Effects of chiropractic spinal manipulation on laser-evoked pain and brain activity

The aim of this study was to examine the mechanisms underlying hypoalgesia induced by spinal manipulation (SM). Eighty-two healthy volunteers were assigned to one of the four intervention groups: no intervention, SM at T4 (homosegmental to pain), SM at T8 (heterosegmental to pain) or light mechanical stimulus at T4 (placebo). Eighty laser stimuli were applied on back skin at T4 to evoke pain and brain activity related to Aδ- and C-fibers activation. The intervention was performed after 40 stimuli. Laser pain was decreased by SM at T4 (p = 0.028) but not T8 (p = 0.13), compared with placebo. However, brain activity related to Aδ-fibers activation was not significantly modulated (all p > 0.05), while C-fiber activity could not be measured reliably. This indicates that SM produces segmental hypoalgesia through inhibition of nociceptive processes that are independent of Aδ fibers. It remains to be clarified whether the effect is mediated by the inhibition of C-fiber activity. [Figure not available: see fulltext.]. © 2021, The Author(s)

Chiropractic spinal manipulation prevents secondary hyperalgesia induced by topical capsaicin in healthy individuals

Background and Aims: Spinal manipulation (SM) is currently recommended for the management of back pain. Experimental studies indicate that the hypoalgesic mechanisms of SM may rely on inhibition of segmental processes related to temporal summation of pain and, possibly, on central sensitization, although this remains unclear. The aim of this study was to determine whether experimental back pain, secondary hyperalgesia, and pain-related brain activity induced by capsaicin are decreased by segmental SM. Methods: Seventy-three healthy volunteers were randomly allocated to one of four experimental groups: SM at T5 vertebral level (segmental), SM at T9 vertebral level (heterosegmental), placebo intervention at T5 vertebral level, or no intervention. Topical capsaicin was applied to the area of T5 vertebra for 40 min. After 20 min, the interventions were administered. Pressure pain thresholds (PPTs) were assessed outside the area of capsaicin application at 0 and 40 min to examine secondary hyperalgesia. Capsaicin pain intensity and unpleasantness were reported every 4 min. Frontal high-gamma oscillations were also measured with electroencephalography. Results: Pain ratings and brain activity were not significantly different between groups over time (p > 0.5). However, PPTs were significantly decreased in the placebo and control groups (p < 0.01), indicative of secondary hyperalgesia, while no hyperalgesia was observed for groups receiving SM (p = 1.0). This effect was independent of expectations and greater than placebo for segmental (p < 0.01) but not heterosegmental SM (p = 1.0). Conclusions: These results indicate that segmental SM can prevent secondary hyperalgesia, independently of expectations. This has implications for the management of back pain, particularly when central sensitization is involved

Adsorption of mono- and multivalent cat- and anions on DNA molecules

Adsorption of monovalent and multivalent cat- and anions on a deoxyribose nucleic acid (DNA) molecule from a salt solution is investigated by computer simulation. The ions are modelled as charged hard spheres, the DNA molecule as a point charge pattern following the double-helical phosphate strands. The geometrical shape of the DNA molecules is modelled on different levels ranging from a simple cylindrical shape to structured models which include the major and minor grooves between the phosphate strands. The densities of the ions adsorbed on the phosphate strands, in the major and in the minor grooves are calculated. First, we find that the adsorption pattern on the DNA surface depends strongly on its geometrical shape: counterions adsorb preferentially along the phosphate strands for a cylindrical model shape, but in the minor groove for a geometrically structured model. Second, we find that an addition of monovalent salt ions results in an increase of the charge density in the minor groove while the total charge density of ions adsorbed in the major groove stays unchanged. The adsorbed ion densities are highly structured along the minor groove while they are almost smeared along the major groove. Furthermore, for a fixed amount of added salt, the major groove cationic charge is independent on the counterion valency. For increasing salt concentration the major groove is neutralized while the total charge adsorbed in the minor groove is constant. DNA overcharging is detected for multivalent salt. Simulations for a larger ion radii, which mimic the effect of the ion hydration, indicate an increased adsorbtion of cations in the major groove.Comment: 34 pages with 14 figure

Effective interaction between helical bio-molecules

The effective interaction between two parallel strands of helical bio-molecules, such as deoxyribose nucleic acids (DNA), is calculated using computer simulations of the "primitive" model of electrolytes. In particular we study a simple model for B-DNA incorporating explicitly its charge pattern as a double-helix structure. The effective force and the effective torque exerted onto the molecules depend on the central distance and on the relative orientation. The contributions of nonlinear screening by monovalent counterions to these forces and torques are analyzed and calculated for different salt concentrations. As a result, we find that the sign of the force depends sensitively on the relative orientation. For intermolecular distances smaller than $6\AA$ it can be both attractive and repulsive. Furthermore we report a nonmonotonic behaviour of the effective force for increasing salt concentration. Both features cannot be described within linear screening theories. For large distances, on the other hand, the results agree with linear screening theories provided the charge of the bio-molecules is suitably renormalized.Comment: 18 pages, 18 figures included in text, 100 bibliog