Strong evidences for a nonextensive behavior of the rotation period in Open Clusters

Time-dependent nonextensivity in a stellar astrophysical scenario combines nonextensive entropic indices $q_{K}$ derived from the modified Kawaler's parametrization, and $q$, obtained from rotational velocity distribution. These $q$'s are related through a heuristic single relation given by $q\approx q_{0}(1-\Delta t/q_{K})$, where $t$ is the cluster age. In a nonextensive scenario, these indices are quantities that measure the degree of nonextensivity present in the system. Recent studies reveal that the index $q$ is correlated to the formation rate of high-energy tails present in the distribution of rotation velocity. On the other hand, the index $q_{K}$ is determined by the stellar rotation-age relationship. This depends on the magnetic field configuration through the expression $q_{K}=1+4aN/3$, where $a$ and $N$ denote the saturation level of the star magnetic field and its topology, respectively. In the present study, we show that the connection $q-q_{K}$ is also consistent with 548 rotation period data for single main-sequence stars in 11 Open Clusters aged less than 1 Gyr. The value of $q_{K}\sim$ 2.5 from our unsaturated model shows that the mean magnetic field topology of these stars is slightly more complex than a purely radial field. Our results also suggest that stellar rotational braking behavior affects the degree of anti-correlation between $q$ and cluster age $t$. Finally, we suggest that stellar magnetic braking can be scaled by the entropic index $q$.Comment: 6 pages and 2 figures, accepted to EPL on October 17, 201

A nonextensive insight to the stellar initial mass function

the present paper, we propose that the stellar initial mass distributions as known as IMF are best fitted by $q$-Weibulls that emerge within nonextensive statistical mechanics. As a result, we show that the Salpeter's slope of $\sim$2.35 is replaced when a $q$-Weibull distribution is used. Our results point out that the nonextensive entropic index $q$ represents a new approach for understanding the process of the star-forming and evolution of massive stars.Comment: 5 pages, 2 figures, Accepted to EP

Multiscale structure of the gravitational wave signal from GW150914 based on the nonextensivity qq-triplet

We study the first gravitational wave, GW150914, detected by advanced LIGO and constructed from the data of measurement of strain relative deformation of the fabric of spacetime. We show that the time series from the gravitational wave obeys Tsallis's $q$-Gaussian distribution as a probability density and its dynamics evolve of the three associated Tsallis' indices named $q$-triplet. This fact strongly suggests that these black hole merger systems behave in a non-extensive manner. Furthermore, our results point out that the entropic indexes obtained as a function of frequency are useful statistical parameters to determine the dominant frequency when black hole coalescence is achieved.Comment: 7 pages, 6 figure

Compost barn system and its influence on the environment, comfort and welfare of dairy cattle

Received: January 16th, 2023 ; Accepted: April 27th, 2023 ; Published: May 15th, 2023 ; Correspondence: [email protected] aim of this study was to evaluate the effect of the thermal environment on behavioral and physiological parameters of crossbred cows of different productivity levels confined in a compost barn system. For this, air temperature (Tdb) and relative humidity (RH) data were measured using sensors/registers and wind speed (Vair) was recorded with the aid of an anemometer. Subsequently, these data were used to calculate the Temperature and Humidity Index (THI). Bedding material variables (pH and humidity) were also evaluated. The animals were evaluated for physiological variables (respiratory rate – RR and surface temperature – ST), scores (body condition, locomotion and dirt) and behavior. The analyses were carried out on two groups of cows (Group 1: high production vs. Group 2: medium and low production). The average pH of the bedding material was 8.5, within the recommended range. In the case of the physiological responses of the cows, the respiratory rate (RR) of Group 1 indicated better conditions of thermal comfort in the morning vs. the afternoon. The system was efficient in both groups based on body condition score, indicating favorable conditions for the health of the animals. Regarding the behavioral evaluation, Group 1 and 2 were statistically similar and had the longest rumination times, in relation to the other evaluated behaviors. Regarding active periods, medium production were the most active. Regarding idle time, low production spent more time idle than the other animals

Small structure, big significance: seed morphology of South American species of M itracarpus (Rubiaceae - Spermacoceae)

Mitracarpus Zuce, ex Schult. & Schult.f. comprises about 50 species distributed mainly throughout tropical and subtropical regions of the New World, from Southern United States to central Argentina. Considering the importance of micromorphological characters for the taxonomy of Spermacoceae s.s. (Rubiaceae), the present study aimed to analyse the taxonomic significance of seed micromorphology in Mitracarpus species from South America. The seeds of 29 species were analysed through light microscopy and scanning electrón microscopy (SEM). For SEM analyses the seeds were mounted on stubs, air dried, covered with gold-palladium. The analyses revealed four pattems and eight subtypes in Mitracarpus, based mainly on the shape of the ventral groove and exotesta features: (1) X-shaped groove: 1.1. reticulate-areolate exotesta, without cruciform depression (M eritricoides, M. parvulus, M. longicalyx, M. nitidus)', 1.2. reticulate-areolate exotesta, with cruciform depression (M. albomarginatus, M. bacigalupoae, M. femandesii); 1.3. reticulate-foveate exotesta, without cruciform depression (M. brasiliensis, M. federalensis, M. hirtus, M. microspermus, M. nitidus, M. polygonifolius); 1.4. papillate exotesta, without cruciform depression (M. pusillus, M. recurvatus, M. steyermarkii); 1.5. reticulate-foveate exotesta, with cruciform depression (M. anthospermoides,M. carajasensis,M. baturitensis,M. bicrucis,M. frigidus); (2) Inverted-Y-shaped groove, reticulate-foveate exotesta, without cruciform depression (M. eichleri, M. salzmannianus, M. semirianus); (3) Rectangularquadrangular-shaped groove, reticulate-areolate exotesta, without cruciform depression (M hasslerianus, M. Ihotzkyanus, M. megapotamicus, M. rigidifolius); (4) Oblong-shaped groove, reticulate-foveate exotesta, without cruciform depression (M. diversifolius). The data obtained here have shown the systematic importance o f seed characteristics in Mitracarpus, as well their valué to indicate affinities among species. It is expected that this study regarding the seed characters in Mitracarpus can provide a potential source o f apomorphies to discem the clades in future molecular phylogenetic analyses. Acknowledgements: FUNCAP (Process BP5-0197-00136.01.00/22); Royal Botanic Gardens, Kew; KLARF (Kew Latín American Research Fellowships Programme); CONICET