Short communication: Effects of the addition of a marigold extract to diets fed to channel catfish (Ictalurus punctatus) on growth parameters

The expansion of aquaculture in the last 10 years has made it an important source of protein worldwide. However, increased production, and the culture intensification it carries, results in higher risk of infectious disease due to poor water quality and high stocking densities. ... Marigold (Tagetes erecta L.) is a plant native to Mexico whose flowers accumulate carotenoids. Natural carotenoids extracted from marigold have been used in aquaculture to help in the survival of fish juvenile stages by strengthening their immunological system, thus reducing mortality rates. The effect of carotenoids in fish health may exert a positive effect on fish growth indices; however, these effects on growth parameters have not been studied in channel catfish (Ictalurus punctatus), which is the most cultured fish species in north-eastern Mexico, and one of the most cultured on the southern United States. Consequently, the aim of this study was to investigate if there were significant differences in growth among channel catfish juveniles when fed diets containing various carotenoid doses from a natural source

Short communication: Effects of the addition of a marigold extract to diets fed to channel catfish (Ictalurus punctatus) on growth parameters

The expansion of aquaculture in the last 10 years has made it an important source of protein worldwide. However, increased production, and the culture intensification it carries, results in higher risk of infectious disease due to poor water quality and high stocking densities. ... Marigold (Tagetes erecta L.) is a plant native to Mexico whose flowers accumulate carotenoids. Natural carotenoids extracted from marigold have been used in aquaculture to help in the survival of fish juvenile stages by strengthening their immunological system, thus reducing mortality rates. The effect of carotenoids in fish health may exert a positive effect on fish growth indices; however, these effects on growth parameters have not been studied in channel catfish (Ictalurus punctatus), which is the most cultured fish species in north-eastern Mexico, and one of the most cultured on the southern United States. Consequently, the aim of this study was to investigate if there were significant differences in growth among channel catfish juveniles when fed diets containing various carotenoid doses from a natural source

Is the evidence for dark energy secure?

Several kinds of astronomical observations, interpreted in the framework of the standard Friedmann-Robertson-Walker cosmology, have indicated that our universe is dominated by a Cosmological Constant. The dimming of distant Type Ia supernovae suggests that the expansion rate is accelerating, as if driven by vacuum energy, and this has been indirectly substantiated through studies of angular anisotropies in the cosmic microwave background (CMB) and of spatial correlations in the large-scale structure (LSS) of galaxies. However there is no compelling direct evidence yet for (the dynamical effects of) dark energy. The precision CMB data can be equally well fitted without dark energy if the spectrum of primordial density fluctuations is not quite scale-free and if the Hubble constant is lower globally than its locally measured value. The LSS data can also be satisfactorily fitted if there is a small component of hot dark matter, as would be provided by neutrinos of mass 0.5 eV. Although such an Einstein-de Sitter model cannot explain the SNe Ia Hubble diagram or the position of the `baryon acoustic oscillation' peak in the autocorrelation function of galaxies, it may be possible to do so e.g. in an inhomogeneous Lemaitre-Tolman-Bondi cosmology where we are located in a void which is expanding faster than the average. Such alternatives may seem contrived but this must be weighed against our lack of any fundamental understanding of the inferred tiny energy scale of the dark energy. It may well be an artifact of an oversimplified cosmological model, rather than having physical reality.Comment: 12 pages, 5 figures; to appear in a special issue of General Relativity and Gravitation, eds. G.F.R. Ellis et al; Changes: references reformatted in journal style - text unchange

Antibody response in patients admitted to the hospital with suspected SARS-CoV-2 infection: results from a multicenter study across Spain

Aim: To evaluate the serological response against SARS-CoV-2 in a multicenter study representative of the Spanish COVID pandemic. Methods: IgG and IgM + IgA responses were measured on 1466 samples from 1236 Spanish COVID-19 patients admitted to the hospital, two commercial ELISA kits (Vircell SL, Spain) based on the detection of antibodies against the viral spike protein and nucleoprotein, were used. Results: Approximately half of the patients presented antibodies (56.8% were IgM + IgA positive and 43.0% were IgG positive) as soon as 2 days after the first positive PCR result. Serological test positivity increased with time from the PCR test, and 10 days after the first PCR result, 91.5% and 88.0% of the patients presented IgM + IgA and IgG antibodies, respectively. Conclusion: The high values of sensitivity attained in the present study from a relatively early period of time after hospitalization support the use of the evaluated serological assays as supplementary diagnostic tests for the clinical management of COVID-19

Categorizing Different Approaches to the Cosmological Constant Problem

We have found that proposals addressing the old cosmological constant problem come in various categories. The aim of this paper is to identify as many different, credible mechanisms as possible and to provide them with a code for future reference. We find that they all can be classified into five different schemes of which we indicate the advantages and drawbacks. Besides, we add a new approach based on a symmetry principle mapping real to imaginary spacetime.Comment: updated version, accepted for publicatio

Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy

We review HB stars in a broad astrophysical context, including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy is presented, which provides unprecedented detail regarding its origin and systematics. We show that the Oosterhoff dichotomy and the distribution of globular clusters (GCs) in the HB morphology-metallicity plane both exclude, with high statistical significance, the possibility that the Galactic halo may have formed from the accretion of dwarf galaxies resembling present-day Milky Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the second-parameter problem is presented. A technique is proposed to estimate the HB types of extragalactic GCs on the basis of integrated far-UV photometry. The relationship between the absolute V magnitude of the HB at the RR Lyrae level and metallicity, as obtained on the basis of trigonometric parallax measurements for the star RR Lyrae, is also revisited, giving a distance modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are studied. Finally, the conductive opacities used in evolutionary calculations of low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and Space Scienc

Perspectives of marine biodiversity studies in Argentina

This paper provides an overview of the research being carried out at the moment by a group of Argentinean scientists working on the subjects of marine biodiversity and oceanography. When the idea of the Census of Marine Life (CoML)was proposed following the Symposium held during the IAPSO-IABO conference in Mar del Plata in October 2001, there was a wide response from the marine scientific community. Information about current research projects, as well as plans for future work in the context of the CoML, were then obtained from about 70 scientists (Appendix I) belonging to 12 institutions located along the Argentinean coast (Appendix II, Figure 1). This has been used to illustrate what is currently being pursued in marine biodiversity in Argentina and which subjects are considered as priority for future research in the area. This paper is, thus, not an historical update of the knowledge of marine biodiversity, but it attempts to give an idea of the current situation and what is planned for the future. The development of an extensive database of what is known on marine biodiversity in the region is considered to be a necessity, but it constitutes a complete project on its own; as such it is included in the proposals for future work (see Future Work in this paper). It is emphasised that this synthesis is not exhaustive in the content of the topics being studied or in the number of researchers working in marine biodiversity in the country. It is, though, considered to be a representative sample of the knowledge in marine science in Argentina today. This is a starting point for the CoML project in South America and it is hoped that, as it develops, it will be improved by the active participation, advice and experience of many other scientists in the region

Clinical phenotypes of acute heart failure based on signs and symptoms of perfusion and congestion at emergency department presentation and their relationship with patient management and outcomes

Objective To compare the clinical characteristics and outcomes of patients with acute heart failure (AHF) according to clinical profiles based on congestion and perfusion determined in the emergency department (ED). Methods and results Overall, 11 261 unselected AHF patients from 41 Spanish EDs were classified according to perfusion (normoperfusion = warm; hypoperfusion = cold) and congestion (not = dry; yes = wet). Baseline and decompensation characteristics were recorded as were the main wards to which patients were admitted. The primary outcome was 1-year all-cause mortality; secondary outcomes were need for hospitalisation during the index AHF event, in-hospital all-cause mortality, prolonged hospitalisation, 7-day post-discharge ED revisit for AHF and 30-day post-discharge rehospitalisation for AHF. A total of 8558 patients (76.0%) were warm+ wet, 1929 (17.1%) cold+ wet, 675 (6.0%) warm+ dry, and 99 (0.9%) cold+ dry; hypoperfused (cold) patients were more frequently admitted to intensive care units and geriatrics departments, and warm+ wet patients were discharged home without admission. The four phenotypes differed in most of the baseline and decompensation characteristics. The 1-year mortality was 30.8%, and compared to warm+ dry, the adjusted hazard ratios were significantly increased for cold+ wet (1.660; 95% confidence interval 1.400-1.968) and cold+ dry (1.672; 95% confidence interval 1.189-2.351). Hypoperfused (cold) phenotypes also showed higher rates of index episode hospitalisation and in-hospital mortality, while congestive (wet) phenotypes had a higher risk of prolonged hospitalisation but decreased risk of rehospitalisation. No differences were observed among phenotypes in ED revisit risk. Conclusions Bedside clinical evaluation of congestion and perfusion of AHF patients upon ED arrival and classification according to phenotypic profiles proposed by the latest European Society of Cardiology guidelines provide useful complementary information and help to rapidly predict patient outcomes shortly after ED patient arrival

Spread of a SARS-CoV-2 variant through Europe in the summer of 2020.

Following its emergence in late 2019, the spread of SARS-CoV-21,2 has been tracked by phylogenetic analysis of viral genome sequences in unprecedented detail3–5. Although the virus spread globally in early 2020 before borders closed, intercontinental travel has since been greatly reduced. However, travel within Europe resumed in the summer of 2020. Here we report on a SARS-CoV-2 variant, 20E (EU1), that was identified in Spain in early summer 2020 and subsequently spread across Europe. We find no evidence that this variant has increased transmissibility, but instead demonstrate how rising incidence in Spain, resumption of travel, and lack of effective screening and containment may explain the variant’s success. Despite travel restrictions, we estimate that 20E (EU1) was introduced hundreds of times to European countries by summertime travellers, which is likely to have undermined local efforts to minimize infection with SARS-CoV-2. Our results illustrate how a variant can rapidly become dominant even in the absence of a substantial transmission advantage in favourable epidemiological settings. Genomic surveillance is critical for understanding how travel can affect transmission of SARS-CoV-2, and thus for informing future containment strategies as travel resumes. © 2021, The Author(s), under exclusive licence to Springer Nature Limited