Testing MOND gravity in the shell galaxy NGC 3923

Context. The elliptical galaxy NGC 3923 is surrounded by numerous stellar shells that are concentric arcs centered on the galactic core. They are very likely a result of a minor merger and they consist of stars in nearly radial orbits. For a given potential, the shell radii at a given time after the merger can be calculated and compared to observations. The Modified Newtonian Dynamics (MOND) is a theory that aims to solve the missing mass problem by modifying the laws of classical dynamics in the limit of small accelerations. Hernquist & Quinn(1987) claimed that the shell distribution of NGC 3923 contradicted MOND, but Milgrom(1988) found several substantial insufficiencies in their work. Aims. We test whether the observed shell distribution in NGC 3923 is consistent with MOND using the current observational knowledge of the shell number and positions and of the host galaxy surface brightness profile, which supersede the data available in the 1980s when the last (and negative) tests of MOND viability were performed on NGC 3923. Methods. Using the 3.6 um bandpass image of NGC 3923 from the Spitzer space telescope we construct the mass profile of the galaxy. The evolution of shell radii in MOND is then computed using analytical formulae. We use 27 currently observed shells and allow for their multi-generation formation, unlike the Hernquist & Quinn one-generation model that used the 18 shells known at the time. Results. Our model reproduces the observed shell radii with a maximum deviation of 5% for 25 out of 27 known shells while keeping a reasonable formation scenario. A multi-generation nature of the shell system, resulting from successive passages of the surviving core of the tidally disrupted dwarf galaxy, is one of key ingredients of our scenario supported by the extreme shell radial range. The 25 reproduced shells are interpreted as belonging to three generations.Comment: 8 pages, 3 figures, Accepted for publication in A&

Quadruple-peaked Line-of-sight Velocity Distributions in Shell Galaxies

We present an improved study of the expected shape of the line-of-sight velocity distribution in shell galaxies. We found a simple analytical expression connecting prominent and in principle observable characteristics of the line profile and mass-distribution of the galaxy. The prediction was compared with the results from a test-particle simulation of a radial merger.Comment: 2 pages, 1 figure, to appear in the Proceedings of JENAM 2010, Symposium 2: "Environment and the formation of galaxies: 30 years later

Different fixative solutions in the detection of mast cells in the canine and feline reproductive organs

Background: The aim of the study was to evaluate the usability of different fixative fluids in the detection of mast cells in ovaries and uteri of female dogs and cats. Materials and methods: Samples were fixed in 4% formaldehyde, Carnoy’s fluid, Mota’s basic lead acetate and isotonic formaldehyde-acetic acid (IFAA). Results: Mast cells (MCs) were detected by acidified toluidine blue staining and counted for various parts of the ovaries and uteri. In the ovaries of both species, the numbers of MCs were significantly (p < 0.05) higher in Carnoy than in formalin. No significant differences were found between Carnoy and Mota (tested only in cats). In the uterus, numbers of MCs were significantly (p < 0.05) higher in Carnoy, Mota and IFAA compared to formalin (canine endometrium, feline endometrium and feline myometrium), in Carnoy and Mota compared to formalin (canine myometrium) and in Mota compared to IFAA (feline myometrium). The majority of MCs were formalin-sensitive in the canine and feline uterus, in the canine ovary and in the feline cortex ovarii. In the feline medulla ovarii, the majority of MCs were formalin-resistant. No formalin-resistant MCs were detected in the feline tunica albuginea ovarii. Conclusions: Thus, using Mota‘s or Carnoy’s fluid in the canine or feline female reproductive organs is recommended. This study improves methodology for all studies which clarify the role of MCs in the reproductive organs of the domestic and laboratory animals

Determinants of depressive symptoms increase in older persons during the COVID-19 pandemic: evidence from Czech cohort study using repeated assessments

Background Numerous studies reported higher levels of mental health issues during the COVID-19 pandemic but only a minority used repeated measurements. We investigated change in depressive symptoms in the Czech ageing cohort and the impact of pre-existing and COVID-19-related stressors. Methods We used data on 2853 participants (mean age 73.4 years) from the Czech part of the prospective Health, Alcohol and Psychosocial factors In Eastern Europe cohort that participated in postal questionnaire surveys before (September 2017-June 2018) and during the pandemic (October 2020-April 2021). Participants reported their depressive symptoms using the Centre for Epidemiological Studies-Depression Scale including 10 (CESD-10) tool. A principal component analysis (PCA) was used to create representative components of the pandemic-related stressors. The impact of the stressors on change in depressive symptoms was tested using multivariable linear regression, after adjustment for age and potential confounders. Results Three patterns of the pandemic-related stressors ( financial stressors', social and perception stressors' and death and hospitalisation stressors') were extracted from the PCA. The mean CESD-10 score increased from 4.90 to 5.37 (p<0.001). In fully adjusted models, significantly larger increases in depression score were reported by older people (β=0.052; p=0.006), those with poor self-rated health (β=0.170; p<0.001), those who experienced death or hospitalisation of a close person (β=0.064; p<0.001), social deprivation (β=0.057; p<0.001), delays in healthcare (β=0.048; p=0.005) and those who suffered from COVID-19 (β=0.045; p=0.008). Conclusion This study confirms an increase in depressive symptoms in older persons during the pandemic and identified several pandemic-related risk factors suggesting that public health policies should address this vulnerable group by adopting the preventing strategies

The explanation of educational disparities in adiposity by lifestyle, socioeconomic and mental health mediators: a multiple mediation model

BACKGROUND: The inverse association between education and obesity was previously found in numerous studies. This study aims to assess several possible mediators in the educational disparities in adiposity. We hypothesize the potential mediating role of lifestyle, socioeconomic, and mental health factors in the association between education and adiposity. METHODS: Cross-sectional population-based sample from Czechia included 2,154 25-64 years old subjects (54.6% women). Education was classified as high, middle, and low. Adiposity was assessed as a latent variable based on body fat percentage, BMI, waist circumference, and visceral fat. The mediation potential of unhealthy dietary behavior, alcohol intake, smoking, sedentary behaviors, income, stress, depression, and quality of life was assessed in age-adjusted sex-specific multiple mediation models. RESULTS: The negative direct effect of education on adiposity was statistically significant at 5% level of significance in both sexes. For men, the indirect effect was statistically significant via sedentary behavior (β = 0.041; 95% CI [0.025–0.062]) with a mediation ratio of 23.7%. In women, the indirect effect was statistically significant via dietary risk (β = −0.023, 95% CI [−0.037, −0.013]), alcohol intake (β = −0.006; 95% CI [−0.014, −0.001]), sedentary behavior (β = 0.012, 95% CI [0.004,0.023]), income (β = −0.022; 95% CI [−0.041, −0.004]), and mental health (β = −0.007; 95% CI [−0.019, −0.001]). The total mediation ratio in women was 30.5%. CONCLUSIONS: Sedentary behaviors had mediating role in the association between education and adiposity in both sexes, with more important role in men. In addition, unhealthy diet and lower income partially mediated the educational gradient in adiposity in women

The influence of salinity on the effects of Multi-walled carbon nanotubes on polychaetes

Salinity shifts in estuarine and coastal areas are becoming a topic of concern and are one of the main factors influencing nanoparticles behaviour in the environment. For this reason, the impacts of multiwalled carbon nanotubes (MWCNTs) under different seawater salinity conditions were evaluated on the common ragworm Hediste diversicolor, a polychaete species widely used as bioindicator of estuarine environmental quality. An innovative method to assess the presence of MWCNT aggregates in the sediments was used for the first time. Biomarkers approach was used to evaluate the metabolic capacity, oxidative status and neurotoxicity of polychaetes after long-term exposure. The results revealed an alteration of energy-related responses in contaminated polychaetes under both salinity conditions, resulting in an increase of metabolism and expenditure of their energy reserves (lower glycogen and protein contents). Moreover, a concentration-dependent toxicity (higher lipid peroxidation, lower ratio between reduced and oxidized glutathione and activation of antioxidant defences and biotransformation mechanisms) was observed in H. diversicolor, especially when exposed to low salinity. Additionally, neurotoxicity was observed by inhibition of Cholinesterases activity in organisms exposed to MWCNTs at both salinities.publishe

Ultrassonografia Doppler na avaliação renal de cadelas diagnosticadas com piometra antes e após tratamento com ovariosalpingohisterectomia

O objetivo do presente estudo foi avaliar a hemodinâmica renal de cadelas com piometra por meio de exames laboratoriais, ultrassonografia Modo B e Doppler, antes e após o tratamento cirúrgico com ovariosanpigohisterectomia (OSH). Foram utilizadas 30 cadelas com diagnóstico de piometra, todas foram submetidas a OSH (momento 1) e 20 foram reavaliadas sete dias após a cirurgia (momento 2). A perfusão renal, o índice de resistividade da artéria renal principal e de cada artéria interlobar (cranial, média e caudal) foi estatisticamente diferente entre os momentos 1 e 2 (p<0,05). Não foi observada diferença estatística para a perfusão renal entre o rim direito e esquerdo no momento 1 e 2. As correlações entre o índice de resistividade da artéria renal principal e as variáveis utilizadas para verificar a função renal foram estabelecidas no momento 1. Para as variáveis correlacionadas ureia, creatinina, proteinúria, relação GGT/creatinina e proteína/creatinina ocorreram associações curvilíneas e positivas com o índice de resistividade da artéria renal principal (p<0,05), no entanto essas correlações foram consideradas de média e fracas. Ao comparar o IR da artéria renal principal com diferentes escores de desidratação e perfusão renal, este foi estatisticamente diferente, e demonstrou aumento da resistência renal em cadelas com moderada redução da perfusão renal, assim como em cadelas desidratadas. Foram avaliadas diversas características de morfologia renal na ultrassonografia Modo B, no entanto, somente as variáveis presença de dilatação de pelve, sinal da medular e outras alterações como áreas de infartos e pontos hiperecogênicos difusos na cortical e medular renal foram estatisticamente distintas de um momento para o outro, com maior frequência no momento 2. Os resultados do presente trabalho demonstram que a ultrassonografia Doppler pode identificar alterações de redução na perfusão renal, por meio do Doppler colorido e o aumento do índice de resistividade das artérias renais em cadelas com piometra. Assim como, a ultrassonografia modo B, embora apresente alterações inespecíficas, pode detectar alterações renais progressivas em cadelas com piometra

Depression as an Escape from Burden of Life

This study aims to explore the inner world of people suffering from depressive disorder. Four people hospitalized in Prague Psychiatric Centre were interviewed. Method of Grounded Theory and discursive analysis revealed a specific way of depressive thinking and experiencing the self and the outer world. Depressive individuals manifest deficit in introspection. They do not perceive themselves as the authors of their lives and they show a tendency to look for external, estranged meanings of life. Combination of these attributes was found to be possible psychological cause leading towards the outburst of depressive disorder. Significant similarities were found between research results and C.G. Jung´s understanding of depressed people, which he describes through energetic model of libido