4982 research outputs found
Sort by
Assessment of some egg quality parameters and chorion ultrastructure characterization in Atlantic salmon (<i> Salmo</i><i> salar)</i> )
No full textFarmed salmonid production requires oocytes and embryos of high quality to supply the increasing market demand; achieving this depends primarily on the management of females and gametes. The chorion of the fertilized egg is a crucial structure for embryo protection; however, it is still poorly studied in some fish species. The object of the present study was to evaluate some parameters of oocyte quality and embryonic development in S. salar, and to characterize the chorion at the ultrastructural level in oocytes and embryos at different stages up to hatching by scanning electron microscopy (SEM). The samples (oocytes and embryos) were obtained from five mature females (4 years old, 9.75 +/- 0.86 kg) of S. salar. The results show 32% (20%; 64%) of oocytes with yolk clots, a hydration percentage of 17% (11.1%; 23.3%) and a significant increase in embryo hardness at 12 accumulated thermal units (ATU). A mean fertility rate of 77% (60%; 93%) was recorded. The survival rates were 72% (20%; 100%) and 73% (32%; 92%) for 130 and 318 ATU, respectively. The values of symmetrical blastomeres were high, 65% (45%; 80%); however, the rate of spine deformities was also high at 42.4% (22%; 71%). Several significant correlations were observed between the parameters assessed: there were high-positive correlations between the hydration percentage and blastomere symmetry (r = 0.89), between oocyte hardness and spine deformities (r = 0.88), and between embryo hardness at 130 and 318 ATU (r = 0.97); there were also strong correlations between symmetry and survival rate at 130 ATU (r = 0.95) and between symmetry and survival rate at 318 ATU (r = 0.96). In the ultrastructural analysis, the SEM images revealed that the outer layer of the chorion of both oocytes and fertilized eggs, through development to hatching, exhibits a granular pattern. In contrast, the inner layer is composed of numerous interconnected fibres that form a complex network, absent in the hatching area. Both outer and inner layers show numerous pore canals. The pores in the outer layer are covered by plugs, and are larger than those in the inner layer. The information generated in this study is useful to complement understanding of the biology of S. salar eggs; however, given the ultrastructural variability of the chorion, further studies are needed to expand on these findings
Disentangling transport movement patterns of trucks either transporting pigs or while empty within a swine production system before and during the COVID-19 epidemic
No full textTransport of pigs between sites occurs frequently as part of genetic improvement and age segregation. However, a lack of transport biosecurity could have catastrophic implications if not managed properly as disease spread would be imminent. However, there is a lack of a comprehensive study of vehicle movement trends within swine systems in the Midwest. In this study, we aimed to describe and characterize vehicle movement patterns within one large Midwest swine system representative of modern pig production to understand movement trends and proxies for biosecurity compliance and identify potential risky behaviors that may result in a higher risk for infectious disease spread. Geolocation tracking devices recorded vehicle movements of a subset of trucks and trailers from a production system every 5 min and every time tracks entered a landmark between January 2019 and December 2020, before and during the COVID-19 pandemic. We described 6,213 transport records from 12 vehicles controlled by the company. In total, 114 predefined landmarks were included during the study period, representing 5 categories of farms and truck wash facilities. The results showed that trucks completed the majority (76.4%, 2,111/2,762) of the recorded movements. The seasonal distribution of incoming movements was similar across years (P > 0.05), while the 2019 winter and summer seasons showed higher incoming movements to sow farms than any other season, year, or production type (P < 0.05). More than half of the in-movements recorded occurred within the triad of sow farms, wean-to-market stage, and truck wash facilities. Overall, time spent at each landmark was 9.08% higher in 2020 than in 2019, without seasonal highlights, but with a notably higher time spent at truck wash facilities than any other type of landmark. Network analyses showed high connectivity among farms with identifiable clusters in the network. Furthermore, we observed a decrease in connectivity in 2020 compared with 2019, as indicated by the majority of network parameter values. Further network analysis will be needed to understand its impact on disease spread and control. However, the description and quantification of movement trends reported in this study provide findings that might be the basis for targeting infectious disease surveillance and control
Carbon nanotube production from algal biochar using microwave irradiation technology
No full textIn this study, we evaluated the transformation of algal-based biochar into carbon nanotubes by irradiation in a microwave oven at low energies (100-300 W). Three species of algae (Macrocystis pyrifera, Sarcothalia crispata, and Scenedesmus almeriensis) were selected and pyrolyzed to obtain biochar for carbon nanotubes (CNTs) growth in the presence of ferrocene as the catalyst. The CNTs obtained were characterized by dynamic light scattering, UV-VIS spectroscopy, Raman spectroscopy, transmission electron microscopy, X-ray diffraction, and electrical conductivity. The results indicate that algal biochar can be used for CNT growth. The heterogeneous structure of algal biochar can initiate the graphitization process for the formation of CNTs. The characteristics of synthesized CNTs vary with the biochar source used as a precursor. Thus, both the degree of graphitization of the wall and the content of nanotubes were higher using biochar with higher carbon content (from microalga Scenedesmus almeriensis); otherwise, the hydrodynamic diameter and electrical conductivity were higher using biochar with upper mineral ash content (from microalga Macrocystis pyrifera). Furthermore, it was found that a low catalyst concentration was required to promote growth due to the reactivity of the mineral ash of the biochar, and it was demonstrated that microwave heating conditions, such as microwave power and temperature, lead to variations in the optical properties of CNTs, such as the band gap energy, CNTs content, and measurement of the size such as the hydrodynamic diameter
Psychomotricity, corporeality, gender and positivist philosophy in Chile: a critical analysis of ministerial documents
No full textFormal education can be understood as a cultural activity that is influenced by multiple epistemological perspectives that are present in society. In addition, each nation has its own particularities based on its own unique history and citizenship. One of the theoretical currents that has had a pedagogical boom in recent years in Latin America is the feminist perspective, promoting gender equality. Considering this context, this essay was developed with the objective of analyzing from a critical and gender perspective four Chilean ministerial documents on psychomotricity and corporeality in early childhood. The analyses showed that there is a marked behaviourist, positivist, neoliberal and uncritical tendency towards gender, psychomotor skills and corporeality in the ministerial texts considered. In this way, it would be promoting an early childhood education that assumes a passive attitude towards social injustices and patriarchal gender stereotypes. In this sense, a technical and traditional curricular rationality is being reproduced among teachers and children
Screening tool development for hand surgery referrals in systemic sclerosis
No full textBackground: Systemic Sclerosis (SSc) patients may need hand surgery. Objective: To develop a screening tool for rheumatologists to identify potential candidates with systemic sclerosis for hand surgery, optimizing referrals.Methods: A pilot cross-sectional study from January 2015 to December 2016. Sample size: 51 participants. Inclusion criteria: = 18 years old, meeting the 2013 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for SSc and hand impairment. Data collected: age, sex, race, disease duration, SSc subtypes, vasodilator use, skin thickness, finger stiffness, presence of Digital Ulcers (DU) and/ or calcinosis, presence of Raynaud's Phenomenon (RP) attacks, health status and disability, disease status, pain intensity and functional status of the hands. Data were analyzed by a multivariate logistic regression model.Results: Fulfillment of surgical criteria: 68.8%. The surgical group had higher scores on the HAQ-DI (1.39 vs. 0.96, p = 0.032) and CHFS (25.0 vs. 12.0, p = 0.005) questionnaires, and a higher frequency of DU (91.43% vs. 18.75%, p < 0.0010), calcinosis (60.0% vs. 0.0%, p < 0.001), use of vasodilators (100.0% vs. 75.0%, p = 0.007) and digital stiffness (28.57% vs. 0.0%, p = 0.017). The presence of DU increased the chance of surgical indication by 46.2 times (ORIC 95% = 8.23 to 259.49). The statistical model showed good accuracy (86.3%, p < 0.001), sensitivity (91.4%), and specificity (81.2%).Conclusion: The presence of DU in SSc could be used as a screening feature for early identification and referral of potential candidates for hand surgery
Slash-Weighted Lindley Distribution: Properties, Inference, and Applications
No full textThe slash-weighted Lindley model is introduced due to the need to obtain a model with more kurtosis than the weighted Lindley distribution. Several expressions for the pdf of this model are given. Its cumulative distribution function is expressed in terms of a generalized hypergeometric function and the incomplete gamma function. Moments and maximum likelihood estimation were studied. A simulation study was carried out to illustrate the good performance of the estimates. Finally, two real applications are included
Effect of exogenous sperm capacitation inducers on stallion sperm
No full textAlthough under appropriate laboratory conditions, sperm from different mammalian species can be capacitated in vitro, the optimal conditions for sperm capacitation in the stallion have been elusive. This study evaluated the effect of different capacitating inducers in Whitten and Tyrode media and assessed their impact on capacitationrelated factors. Stallion sperm were incubated with different combinations of capacitating inducers at 38.5 degrees C in an air atmosphere. Sperm quality variables such as motility, mitochondrial membrane potential, and lipid peroxidation were assessed. Membrane fluidity and intracellular calcium levels were evaluated as early markers of capacitation, while tyrosine phosphorylation events and the sperm's ability to perform acrosomal exocytosis were used as late capacitation markers. Finally, these sperm were evaluated using a heterologous zona pellucida binding assay. The findings confirm that capacitating conditions evaluated increase intracellular calcium levels and membrane fluidity in both media. Similarly, including 2 or 3 inducers in both media increased tyrosine phosphorylation levels and acrosomal exocytosis after exposure to progesterone, confirming that stallion sperm incubated in these conditions shows cellular and molecular changes consistent with sperm capacitation. Furthermore, the zona pellucida binding assay confirmed the binding capacity of sperm incubated in capacitation conditions, a key step for stallion in vitro fertilization success. Further studies are needed to evaluate the effect of these conditions on in vitro fertilization in the horse
Low-Cost Sensors Technologies for Monitoring Sustainability and Safety Issues in Mining Activities: Advances, Gaps, and Future Directions in the Digitalization for Smart Mining
No full textNowadays, monitoring aspects related to sustainability and safety in mining activities worldwide are a priority, to mitigate socio-environmental impacts, promote efficient use of water, reduce carbon footprint, use renewable energies, reduce mine waste, and minimize the risks of accidents and fatalities. In this context, the implementation of sensor technologies is an attractive alternative for the mining industry in the current digitalization context. To have a digital mine, sensors are essential and form the basis of Industry 4.0, and to allow a more accelerated, reliable, and massive digital transformation, low-cost sensor technology solutions may help to achieve these goals. This article focuses on studying the state of the art of implementing low-cost sensor technologies to monitor sustainability and safety aspects in mining activities, through the review of scientific literature. The methodology applied in this article was carried out by means of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and generating science mapping. For this, a methodological procedure of three steps was implemented: (i) Bibliometric analysis as a quantitative method, (ii) Systematic review of literature as a qualitative method, and (iii) Mixed review as a method to integrate the findings found in (i) and (ii). Finally, according to the results obtained, the main advances, gaps, and future directions in the implementation of low-cost sensor technologies for use in smart mining are exposed. Digital transformation aspects for data measurement with low-cost sensors by real-time monitoring, use of wireless network systems, artificial intelligence, machine learning, digital twins, and the Internet of Things, among other technologies of the Industry 4.0 era are discussed
HUMAN SPACE PROJECT: MUSEUM AND GARDEN
No full textFor the authors of this winning competition entry to house sculptor Mario Irarrazabal's work, a museum can be understood as a garden-defined by its limits but also open to change. For us at ARQ , this project also demonstrates how buildings can be tools for ecological recovery, wherein the logic of their positioning, circulation, and infrastructural networks are treated as opportunities to favor the more-than -human species that already inhabit the site