Physical separation and reduction of contact duration with sexually hyperactive bucks decrease testosterone concentrations and sexual behaviour in bucks in sexual rest.

Sexually hyperactive bucks are more efficient than sexually hypoactive bucks in stimulating testosterone secretion and sexual behaviour in other bucks in seasonal sexual rest by the phenomenon that we called the "buck-to-buck effect". Here, we determined whether physical separation and reduction of the duration of contact with the sexually hyperactive bucks would modify those parameters in sexually hypoactive bucks exposed to the "buck-to-buck effect". Bucks were subjected to natural day length throughout the study; this was the sexually hypoactive group.

Inorganic Polyphosphate Affects Biofilm Assembly, Capsule Formation, and Virulence of Hypervirulent ST23 .

The emergence of hypervirulent (hvKP) strains poses a significant threat to public health due to high mortality rates and propensity to cause severe community-acquired infections in healthy individuals. The ability to form biofilms and produce a protective capsule contributes to its enhanced virulence and is a significant challenge to effective antibiotic treatment. Polyphosphate kinase 1 (PPK1) is an enzyme responsible for inorganic polyphosphate synthesis and plays a vital role in regulating various physiological processes in bacteria.

Genomic epidemiology of isolated from bloodstream infections in South America during 2019 supports regional surveillance.

remains one of the leading causes of infections worldwide and a common cause of bacteraemia. However, studies documenting the epidemiology of in South America using genomics are scarce. We hereby report on the largest genomic epidemiology study to date of both methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) in South America, conducted by the StaphNET-SA network.

Seismic Performance Assessment of a Moment-Resisting Frame Steel Warehouse Provided with Overhead Crane.

The purpose of this study is to analyze the nonlinear behavior of a steel warehouse structured by moment-resistant frames, which utilizes an overhead crane on its interior brackets and as an external load of the weight of the lining panels. The analysis methods used are (i) pushover analysis, which consists of applying an incremental force in the transverse and longitudinal direction to obtain the capacity curve of the structure; (ii) time-history analysis, in which different records of destructive earthquakes that occurred in Chile are used in order to analyze the response of the structure to these loads. The results indicate that the transverse direction is more ductile than the direction of the structure within the pushover and time-history methods but not using the N2 method.

Performance of Medium-Rise Buildings with Reinforced Concrete Shear Walls Designed for High Seismic Hazard.

This work has evaluated the collapse fragility of a typical Chilean building for residential use, structured based on shear-resistant RC walls and inverted beams arranged along its entire perimeter, using the incremental dynamic analysis (IDA) for the evaluation of its structural behavior, using for this the 2018 version of the SeismoStruct software. This method evaluates the global collapse capacity of the building from the graphical representation of its maximum inelastic response, obtained through a non-linear time-history analysis, against the scaled intensity of a set of seismic records obtained in the subduction zone, thus creating the IDA curves of the building. The processing of the seismic records is included within the applied methodology to make them compatible with the elastic spectrum of the Chilean design, achieving an adequate seismic input in the two main structural directions.

Milk let-down in goats can be influenced by the type of stimuli applied or to which goats are exposed during suckling and hand milking.

The present experiments on goats were conducted with the aim of verifying (a) whether the identity of the goat kids can affect the characteristics of milk let-down during suckling (Study 1) and (b) whether the presence of the goat kids may improve the milk let-down during hand milking (Study 2). In Study 1, 16 lactating goats with twins and 12 with single kids were used. Dams with single goat kids ejected more milk when suckling their kids at Days 5 and 20 of lactation, than when suckling aliens.

Efficient water treatment achieved in recirculating aquaculture system using woodchip denitrification and slow sand filtration.

For a recirculating aquaculture system (RAS), a passive water treatment system was designed for efficient discharge nutrient removal and water reuse in RAS production. Denitrification in a woodchip bioreactor filled with birch wood (Betula pendula) followed by sand filtration was introduced into a side-loop of an experimental RAS rearing rainbow trout (Oncorhynchus mykiss). Denitrification efficiency remained high (96%) throughout the experiment and reached a nitrogen removal rate of 15 g NO-N m per day.

Solids management in freshwater-recirculating aquaculture systems: Effectivity of inorganic and organic coagulants and the impact of operating parameters.

Coagulants are widely used for solids (uneaten food, faeces, etc.) management in recirculating aquaculture systems (RAS), but no recent research has been performed on the effectiveness of different coagulants in treatment of aquaculture sludge. This study examined the effectivity of selected inorganic (polyaluminium chloride, PAC) and organic products (polyamine- and starch-based) as coagulant agents for solids management in RAS.

Undernutrition reduces the body weight and testicular size of bucks exposed to long days but not their ability to stimulate reproduction of seasonally anestrous goats.

In semiarid conditions, feed is often scarce and variable with underfeeding being common; these factors can potentially induce fertility reductions in both sexes. Sexually active bucks are able to very efficiently fertilize out-of-season goats, but we do not know whether underfeeding would reduce the ability of bucks to fertilize goats during these periods. Two experiments were conducted to determine (i) testicular size and change of odor intensity of undernourished bucks exposed to long days and (ii) the ability of these bucks to stimulate reproductive activity in seasonally anestrous goats.

A comparison of photolytic, photochemical and photocatalytic processes for disinfection of recirculation aquaculture systems (RAS) streams.

The development of technologically advanced recirculation aquaculture systems (RAS) implies the reuse of water in a high recirculation rate (>90%). One of the most important phases for water management in RAS involves water disinfection in order to avoid proliferation of potential pathogens and related fish diseases. Accordingly, different approaches have been assessed in this study by performing a comparison of photolytic (UV-LEDs) at different wavelengths (λ = 262, 268 and 262 + 268 nm), photochemical (UV-LEDs/HO, UV-LEDs/HSO and UV-LEDs/SO) and photocatalytic (TiO/SiO/UV-LEDs and ZnO/SiO/UV-LEDs) processes for the disinfection of water in RAS streams.

Water quality in recirculating aquaculture system using woodchip denitrification and slow sand filtration.

In recirculating aquaculture system (RAS), ammonium excreted by the fish is typically transformed to less toxic nitrate by microbial activity in bioreactors. However, nitrate-nitrogen load can be harmful for the receiving water body when released from the RAS facility. A new type of water treatment system for a RAS was designed, including a passive woodchip denitrification followed by a sand filtration introduced into a side-loop of an experimental RAS, rearing rainbow trout (Oncorhynchus mykiss).

Depuration of geosmin- and 2-methylisoborneol-induced off-flavors in recirculating aquaculture system (RAS) farmed European whitefish .

European whitefish has increasingly become an important species for aquatic food production, especially in the Nordic countries. Whitefish is produced in traditional cage and pond operations, and in recirculating aquaculture system (RAS) in which, unfortunately, off-flavors and odors, mostly caused by geosmin (GSM) and 2-methylisoborneol (MIB), can accumulate in fish flesh from the circulating water. GSM and MIB have very low human sensory detection limits and, therefore, often disliked by consumers even at low concentrations.

The Fate of Bacteriophages in Recirculating Aquaculture Systems (RAS)-Towards Developing Phage Therapy for RAS.

Aquaculture production has increased tremendously during the last decades, and new techniques have been developed, e.g., recirculating aquaculture systems (RAS).

Melatonin administration during the dry period stimulates subsequent milk yield and weight gain of offspring in subtropical does kidding in summer.

In the present experiment, we tested the hypothesis that in does kidding in summer, melatonin administration during dry period is galactopoietic for the subsequent lactation and results in improved growth of their suckling kids. Twenty-five multiparous pregnant creole does were enrolled into a randomized complete block design during their dry period in the 49 d prepartum, and under natural long photoperiods around the summer solstice, pregnant does either received 2 subcutaneous ear implants (18 mg) of melatonin (MEL, n = 10) or served as nonimplanted controls (CONT, n = 15). During the first 14 wk of subsequent lactation (suckling and milking periods), MEL does yielded more milk than CONT does.

In dual-purpose subtropical goats, 1 h of extra-light given from 16 to 17 h after dawn (pulse of light) in winter stimulates milk yield.

This research communication addresses the hypothesis that in dual-purpose goats, exposure to 1 h of extra-light given from 16 to 17 h after dawn (pulse of light) in winter stimulates milk yield. One group of goats was maintained under natural short photoperiod (natural day; ND (n = 7)). Another group of lactating females was submitted to an artificial long-day photoperiod consisting of 16 h light and 8 h darkness (long days; LD (n = 7)).

Continuous presence of females in estrus does not prevent seasonal inhibition of LH and androgen concentrations in bucks.

In male goats, being in permanent visual contact with females in estrus does not prevent seasonal variation in certain endocrine hormone levels and sexual activities. In this study, we tested whether continuous and full contact with females in estrus prevented seasonal endocrinological variation in bucks. In 1 experiment (Exp.

Sexually active bucks counterbalance the seasonal negative feedback of estradiol on LH in ovariectomized goats.

We showed previously that the permanent presence of bucks rendered sexually active by photoperiodic treatments, thereafter called photostimulated bucks, prevents the occurrence of seasonal anovulation; also, the introduction of these sexually active bucks induces ovulations during seasonal anestrus. Here, we studied the response of ovariectomized goats bearing 12-mm subcutaneous implants filled or not with estradiol to sexually active males to determine (1) whether the permanent presence of such bucks prevents the decrease of LH despite the presence of a negative feedback by estradiol mimicking that of seasonal anestrus (experiment 1) and (2) whether the introduction of photostimulated bucks increases the plasma LH concentrations in spite of this negative feedback (experiment 2). In experiment 1, one group of goats remained in contact with sexually active bucks, whereas the other group remained in contact with control bucks.

Fifteen minutes of daily contact with sexually active male induces ovulation but delays its timing in seasonally anestrous goats.

The present experiment was conducted to determine (1) whether the sexually active bucks are able to stimulate the ovulatory activity of seasonal anestrous goats when the daily contact is reduced to 15 min/day during 15 days and (2) the exact ovulatory activity in anestrous goats exposed to bucks for 2 hours or less per day during 15 days. One group of goats (n = 15) was isolated from bucks. The other six groups (n = 15 each) were exposed to sexually active bucks (n = 1 each) for 15 minutes, 30 minutes, 1 hour, 2 hours, 4 hours, or 24 hours during 15 days.

Sexually active males prevent the display of seasonal anestrus in female goats.

A well-defined season of sexual rest controlled by photoperiod is observed in female sheep and goats during spring and summer, delineating their "anestrous season"; bucks also decrease sexual activity at about the same time. Nutrition and/or socio-sexual stimuli play only secondary roles. However, the presence of sexually active males can reduce the length of seasonal anestrus.

Importance of intense male sexual behavior for inducing the preovulatory LH surge and ovulation in seasonally anovulatory female goats.

The present study was carried out to determine whether the presence of photostimulated sedated male goats could stimulate the LH preovulatory surge and ovulation in seasonal anestrous goats. Sexually experienced male goats were treated with artificial long days (16 hours light per day) from 1 November to 15 January to stimulate their sexual activity in March and April, corresponding to the natural sexual rest. A female group of goats (n=20) was exposed to non-sedated males who displayed an intense sexual behavior and provided strong odor (non-sedated group).

Two or 24 h of daily contact with sexually active males results in different profiles of LH secretion that both lead to ovulation in anestrous goats.

Two experiments were conducted to (a) determine whether sexually active males are able to stimulate the sexual activity of anestrous female goats when duration of contact is reduced to an intermittent contact shorter than 4 daily hours and (b) compare the pattern of secretion of LH when anestrous goats are exposed either permanently or intermittently to males. In the first experiment, 4 groups of anovulatory goats were exposed to sexually active males for 24, 4, 2, or 1 h/d during 15 consecutive days, whereas control females remained isolated. More than 89% of females in the groups exposed to the sexually active bucks ovulated, whereas only 5% did so in the control group (P < 0.

Effects of melatonin on oxidative stress, and resistance to bacterial, parasitic, and viral infections: a review.

Melatonin, a hormone secreted by the pineal gland, works directly and indirectly as a free radical scavenger. Its other physiological or pharmacological activities could be dependent or independent of receptors located in different cells, organs, and tissues. In addition to its role in promoting sleep and circadian rhythms regulation, it has important immunomodulatory, antioxidant, and neuroprotective effects suggesting that this indole must be considered as a therapeutic alternative against infections.

Male goat vocalizations stimulate the estrous behavior and LH secretion in anestrous goats that have been previously exposed to bucks.

We investigated whether live vocalizations emitted by bucks interacting with anestrous females stimulate secretion of LH, estrous behavior and ovulation in anestrous goats. In experiment 1, bucks rendered sexually active by exposure to long days followed by natural photoperiod were exposed in a light-proof-building to five anestrous females. Buck vocalizations were reproduced through a microphone-amplifier-loudspeaker system to an open pen where one group of goats (n=6) was exposed for 10 days to these live vocalizations.

Sexually active bucks are able to stimulate three successive groups of females per day with a 4-hour period of contact.

Bucks rendered sexually active by a photoperiod treatment of long days can induce fertile ovulation in a group of goats with only 4 h of contact daily with a male:female ratio of 1:10. Here we tested whether such bucks could induce fertile ovulations when stimulating successively three different groups of anovulatory goats when interacting 4 h per day during 15 consecutive days. Control males (n=3) were introduced in the control group (n=25) of does at 8:00 h and were removed at 12:00 h.

Lack of sexual experience does not reduce the responses of LH, estrus or fertility in anestrous goats exposed to sexually active males.

We investigated whether LH secretion, estrous behavior and fertility would differ between sexually inexperienced and experienced anestrous goats exposed to the males. Male goats were rendered sexually active during the reproductive rest season by exposure to 2.5 months of artificial long days.