On the Entropy and the Density Matrix of Cosmological Perturbations

We look at the transition to the semiclassical behaviour and the decoherence process for the inhomogeneous perturbations in the inflationary universe. Two different decoherence mechanisms appear: one dynamical, accompanied with a negligible, if at all, entropy gain, and the other, effectively irreversible dephasing, due to a rapid variation in time of the off-diagonal density matrix elements in the post-inflationary epoch. We thus settle the discrepancies in the entropy content of perturbations evaluated by different authors.Comment: LaTeX2e with the epsf packag

Scavenger guild and consumption patterns of an invasive alien fish species in a Mediterranean wetland

Invasive Alien Species (IAS) alter ecosystems, disrupting ecological processes and driving the loss of ecosystem services. The common carp Cyprinus carpio is a hazardous and widespread IAS, becoming the most abundant species in many aquatic ecosystems. This species transforms ecosystems by accumulating biomass to the detriment of other species, thus altering food webs. However, some terrestrial species, such as vertebrate scavengers, may benefit from dead carps, by incorporating part of the carp biomass into the terrestrial environment. This study describes the terrestrial vertebrate scavenger assemblage that benefits from carp carcasses in a Mediterranean wetland. We also evaluate the seasonal differences in the scavenger assemblage composition and carrion consumption patterns. Eighty carp carcasses (20 per season) were placed in El Hondo Natural Park, a seminatural mesohaline wetland in south-eastern Spain, and we monitored their consumption using camera traps. We recorded 14 scavenger species (10 birds and four mammals) consuming carp carcasses, including globally threatened species. Vertebrates consumed 73% of the carrion biomass and appeared consuming at 82% of the carcasses. Of these carcasses consumed, 75% were completely consumed and the mean consumption time of carcasses completely consumed by vertebrates was 44.4 h (SD = 42.1 h). We recorded differences in species richness, abundance, and assemblage composition among seasons, but we did not find seasonal differences in consumption patterns throughout the year. Our study recorded a rich and efficient terrestrial vertebrate scavenger assemblage benefitting from carp carcasses. We detected a seasonal replacement on the scavenger species, but a maintenance of the ecological function of carrion removal, as the most efficient carrion consumers were present throughout the year. The results highlight the importance of vertebrate scavengers in wetlands, removing possible infectious focus, and moving nutrients between aquatic and terrestrial environments.JMPG was supported by Spanish Ministry of Science, Innovation and Universities contracts (IJC-2019-038968). ESG received the grants PID 2021-124744NA-I00 and RYC2019-027216-I funded by MCIN/AEI/ https://doi.org/10.13039/501100011033 and by ESF Investing in your future

Evaluation of the small ruminants cystic ovarian disease using transrectal ultrasonography

A transrectal ultrasonic method using a 7.5 MHz linear-array transducer was used in 194 ewes and 39 goats to study the characteristc of cystic ovaries. Cystic structures found on the ovaries include follicular cysts and luteinised cysts. Follicular cysts showed up as non-echogenic structures with a 1.5 ± 0.4 cm diameter. The cysts luteinised showed an echogenic rim of tissue, ranging from 2- 3 mm, around the cyst; the central cavity was 1±0.2 cm. In total, 4.1 percent of ewes and 5.1 percent of goats exhibited follicular cysts. Only 1 percent of ewes and 2.6 percent of goats showed luteinised cysts. In conclusion, the results demonstrated that transrectal ultrasonography provides a noninvasive form of visual access to the ovary from small ruminants, to evaluate pathological changes before the aplication of superovulation treatments and embryo transfer.Se ha realizado un estudio de las características ecográficas de estructuras quísticas ováricas en 194 ovejas y 39 cabras de diferentes razas y procedentes de distintas zonas geográficas, con el objeto de valorar la ecografía transrectal con sondas de alta resolución (7,5 MHz) como criterio de selección de animales destinados a programas de superovulación y recogida de embriones. Los quistes foliculares tenían una incidencia de presentación del 4,1 p.100 en las ovejas y del 5,1 p.100 en las cabras, presentándose ecográficamente con una morfología esférica anecoica de 1,5±0,4 cm de diámetro, con paredes finas y generalmente bien definidas. Los quistes luteínicos tuvieron una presentación del 1 p.100 en las ovejas y del 2,6 p.100 en las cabras. Ecográficamente se caracterizaban por presentar una cavidad central anecógena 1±0,2 cm, rodeada por un anillo ecogénico de 2-3 mm de espesor. No había diferencias significativas en la frecuencia de presentación de quistes ováricos entre ambas especies. Los resultados muestran que la ecografía transrectal con sondas de alta resolución permite la realización de un diagnóstico eficaz de la patología quística ovárica en los pequeños rumiantes, siendo recomendable esta metodología en la selección de hembras donantes y receptoras

Unravelling the vertebrate scavenger assemblage in the Gobi Desert, Mongolia

Despite the essential role that vertebrate scavengers play in ecosystems, most studies have been conducted in Europe and North America, and there is a lack of information on vertebrate scavengers in vast regions of the world. Our aim was to describe the functioning and composition of the unknown vertebrate scavenger assemblage in the Gobi Desert, Mongolia, and determine how carcass size and habitat type affect species composition and carrion use. We monitored carcasses with camera traps and we also conducted observation points to survey the raptor community and identify the proportion of raptor species making use of the carcasses. We recorded eight vertebrate scavenger species (five birds and three mammals) by camera trap and seven raptors at observation points. Over half of the raptor species recorded at the observation points were also found feeding on carrion. The two most threatened species were only recorded in the mountain habitat. Furthermore, scavenger abundance and consumption rates were higher at large carcasses. This study highlights the importance of scavenging by raptors and other vertebrate scavengers for carrion elimination in ecosystems with extreme climatic conditions.AOT, JMPG, ZMR, LNA and ESG were supported by Generalitat Valenciana (SEJI/2018/024), ZMR and LNA also by contracts co-funded by the Generalitat Valenciana and the European Social Fund (APOSTD/2019/016 and ACIF/2019/056, respectively), and JASZ by funds from the Spanish Ministry of Science, Innovation and Universities and the European Regional Development Fund (RTI 2018-099609-B-C21)

Near-IR observations of the young star [BHB2007]-1: A sub-stellar companion opening the gap in the disk

The presence of planets or sub-stellar objects still embedded in their native protoplanetary disks is indirectly suggested by disk sub-structures like gaps, cavities, and spirals. However, these companions are rarely detected. We present VLT/NACO high-contrast images in $J$, $H$, $K_S$, and $L^{\prime}$ band of the young star [BHB2007]-1 probing the inclined disk in scattered light and revealing the probable presence of a companion. The point source is detected in the $L^{\prime}$ band in spatial correspondence with complementary VLA observations. This object is constrained to have a mass in the range of 37-47 M$_{Jup}$ and is located at 50 au from the central star, inside the 70 au-large disk cavity recently imaged by ALMA, that is absent from our NACO data (down to 20 au). This mass range is compatible with the upper end derived from the size of the ALMA cavity. The NIR disk brightness is highly asymmetric around the minor axis, with the southern side 5.5 times brighter than the northern side. The constant amount of asymmetry across all wavelengths suggests that it is due to a shadow cast by a misaligned inner disk. The massive companion that we detect could, in principle, explain the possible disk misalignment, as well as the different cavity sizes inferred by the NACO and ALMA observations. The confirmation and characterization of the companion is entrusted to future observations.Comment: 9 pages, 5 figures, 3 tables. Accepted for publication on Ap

Inner edges of planetesimal belts: collisionally eroded or truncated?

The radial structure of debris discs can encode important information about their dynamical and collisional history. In this paper we present a 3-phase analytical model to analyse the collisional evolution of solids in debris discs, focusing on their joint radial and temporal dependence. Consistent with previous models, we find that as the largest planetesimals reach collisional equilibrium in the inner regions, the surface density of dust and solids becomes proportional to $\sim r^{2}$ within a certain critical radius. We present simple equations to estimate the critical radius and surface density of dust as a function of the maximum planetesimal size and initial surface density in solids (and vice versa). We apply this model to ALMA observations of 7 wide debris discs. We use both parametric and non-parametric modelling to test if their inner edges are shallow and consistent with collisional evolution. We find that 4 out of 7 have inner edges consistent with collisional evolution. Three of these would require small maximum planetesimal sizes below 10 km, with HR 8799's disc potentially lacking solids larger than a few centimeters. The remaining systems have inner edges that are much sharper, which requires maximum planetesimal sizes $\gtrsim10$ km. Their sharp inner edges suggest they could have been truncated by planets, which JWST could detect. In the context of our model, we find that the 7 discs require surface densities below a Minimum Mass Solar Nebula, avoiding the so-called disc mass problem. Finally, during the modelling of HD 107146 we discover that its wide gap is split into two narrower ones, which could be due to two low-mass planets formed within the disc.Comment: Accepted for publication in MNRAS, 21 pages, 11 figure

Global ecological predictors of the soil priming effect.

Identifying the global drivers of soil priming is essential to understanding C cycling in terrestrial ecosystems. We conducted a survey of soils across 86 globally-distributed locations, spanning a wide range of climates, biotic communities, and soil conditions, and evaluated the apparent soil priming effect using 13C-glucose labeling. Here we show that the magnitude of the positive apparent priming effect (increase in CO2 release through accelerated microbial biomass turnover) was negatively associated with SOC content and microbial respiration rates. Our statistical modeling suggests that apparent priming effects tend to be negative in more mesic sites associated with higher SOC contents. In contrast, a single-input of labile C causes positive apparent priming effects in more arid locations with low SOC contents. Our results provide solid evidence that SOC content plays a critical role in regulating apparent priming effects, with important implications for the improvement of C cycling models under global change scenarios