Galactic Punctuated Equilibrium: How to Undermine Carter's Anthropic Argument in Astrobiology

We investigate a new strategy which can defeat the (in)famous Carter's "anthropic" argument against extraterrestrial life and intelligence. In contrast to those already considered by Wilson, Livio, and others, the present approach is based on relaxing hidden uniformitarian assumptions, considering instead a dynamical succession of evolutionary regimes governed by both global (Galaxy-wide) and local (planet- or planetary system-limited) regulation mechanisms. This is in accordance with recent developments in both astrophysics and evolutionary biology. Notably, our increased understanding of the nature of supernovae and gamma-ray bursts, as well as of strong coupling between the Solar System and the Galaxy on one hand, and the theories of "punctuated equilibria" of Eldredge and Gould and "macroevolutionary regimes" of Jablonski, Valentine, et al. on the other, are in full accordance with the regulation- mechanism picture. The application of this particular strategy highlights the limits of application of Carter's argument, and indicates that in the real universe its applicability conditions are not satisfied. We conclude that drawing far-reaching conclusions about the scarcity of extraterrestrial intelligence and the prospects of our efforts to detect it on the basis of this argument is unwarranted.Comment: 3 figures, 26 page

The Krzyż conjecture revisited

The Krzyz conjecture concerns the largest values of the Taylor coefficients of a non-vanishing analytic function bounded by one in modulus in the unit disk. It has been open since 1968 even though information on the structure of extremal functions is available. The purpose of this paper is to collect various conditions that the coefficients of an extremal function (and various other quantities associated with it) should satisfy if the conjecture is true and to show that each one of these properties is equivalent to the conjecture itself. This may provide several possible starting points for future attempts at solving the problemThe first, third and fourth authors thankfully acknowledge partial support from MINECO grant MTM2012-37436-C02-02, Spain. Starting in 2014 the first author was supported by Academy of Finland grant 268009. The second author was supported by NSERC, Canada. The third author was also supported by NSF grant DMS-0901524, by NSF CAREER, Award No. DMS-1056965, and Sloan Research Fellowship, USA. The fourth author was partially supported by the European ESF Network HCAA (“Harmonic and Complex Analysis and Its Applications”) during the period November 2009 - April 201

A search for candidate radio supernova remnants in the nearby irregular starburst galaxies NGC 4214 and NGC 4395

We present the results of a search for new candidate radio su­pernova remnants (SNRs) in the nearby starburst irregular galaxies NGC 4214 and NGC 4395 using archived radio observations made with the Very Large Array (VLA) at the wavelengths of 3.5 cm, 6 cm and 20 cm for NGC 4214 and 6 cm and 20 cm for NGC 4395. These observations were analyzed as part of our ongoing search for candidate radio SNRs in nearby galaxies: the goal of this search is to prepare a large sample of candidate radio SNRs for the purpose of a robust statistical study of the properties of these sources. Based on our analysis, we have confirmed the nonthermal nature of the discrete radio sources α and β in NGC 4214 and classify these sources as candidate radio SNRs based on their positional coincidences with HII regions in that galaxy. We have measured the flux densities of the two candidate radio SNRs at each wavelength and calculated corresponding spectral indices: we have also measured flux densities of two other discrete radio sources in these galaxies - ρ in NGC 4214 and #3 in NGC 4395 which we suspect to be additional candidate radio SNRs based on their positional coincidences with other HII regions in these galaxies. However, the radio data presently available for these sources can­not confirm such a classification and additional observations are needed. We have also calculated the radio luminosities Lradio at the wavelength of 20 cm for these two candidate radio SNRs as well as the corresponding values for the minimum total energy Emin required to power these radio sources via synchrotron emission and the corresponding magnetic field strength Bmin. We have compared our mean calculated values for these properties with the mean values for populations of candidate radio SNRs in other starburst galaxies: while the values for Lradio and Bmin are roughly comparable to the values seen in other starburst galaxies, the mean value for Emin is higher than the mean value of any other starburst galaxy. Finally, we include these two candidate radio SNRs in a discussion of the Σ − D relation for extragalactic candidate radio SNRs and find that these sources are located on the shallower end of the master Σ − D relation for all extragalactic SNRs as derived by Urošević et al.(2005).published_or_final_versio

Astrobiological Complexity with Probabilistic Cellular Automata

Search for extraterrestrial life and intelligence constitutes one of the major endeavors in science, but has yet been quantitatively modeled only rarely and in a cursory and superficial fashion. We argue that probabilistic cellular automata (PCA) represent the best quantitative framework for modeling astrobiological history of the Milky Way and its Galactic Habitable Zone. The relevant astrobiological parameters are to be modeled as the elements of the input probability matrix for the PCA kernel. With the underlying simplicity of the cellular automata constructs, this approach enables a quick analysis of large and ambiguous input parameters' space. We perform a simple clustering analysis of typical astrobiological histories and discuss the relevant boundary conditions of practical importance for planning and guiding actual empirical astrobiological and SETI projects. In addition to showing how the present framework is adaptable to more complex situations and updated observational databases from current and near-future space missions, we demonstrate how numerical results could offer a cautious rationale for continuation of practical SETI searches.Comment: 37 pages, 11 figures, 2 tables; added journal reference belo

The Sigma - D relation for planetary nebulae

We present an extended analysis of the relation between radio surface brightness and diameter -- the so-called $\Sigma-D$ relation for planetary nebulae (PNe). We revise our previous derivation of the theoretical $\Sigma-D$ relation for the evolution of bremsstrahlung surface brightness in order to include the influence of the fast wind from the central star. Different theoretical forms are derived: $\Sigma \propto D^{-1}$ for the first and second phases of evolution and $\Sigma\propto D^{-3}$ for the final stage of evolution. Also, we analyzed several different Galactic PN samples. All samples are influenced by severe selection effects, but Malmquist bias seems to be less influential here than in the supernova remnant (SNR) samples. We derived empirical $\Sigma-D$ relations for 27 sample sets using 6 updated PN papers from which an additional 21 new sets were extracted. Twenty four of these have a trivial form of $\beta \approx 2$. However, we obtain one empirical $\Sigma-D$ relation that may be useful for determining distances to PNe. This relation is obtained by extracting a recent nearby (< 1 kpc) Galactic PN sample.Comment: 12 pages, 3 tables, 4 figures. Accepted for publication in Astronomy & Astrophysic

NOS3 gene variants and male infertility: Association of 4a/4b with oligoasthenozoospermia

Results of recent studies confirmed that oxidative stress negatively affects sperm motility and causes sperm DNA damage. Produced by nitric oxide synthase 3 (NOS3), nitric oxide is considered to be one of the important mediators of oxidative stress in testis tissue. The aim of this study was to assess the possible association of three genetic variants (rs2070744, rs1799983 and intron variant 4a/4b) in NOS3 gene and infertility occurrence in two groups of infertile men (idiopathic azoospermia and oligoasthenozoospermia) and fertile controls. Genotypes for the single-nucleotide genetic variants rs1799983 and rs2070744 were determined by PCR-RFLP, while genotyping of intron 4 variant 4a/4b was performed by gel electrophoresis of PCR products. Statistical analysis was performed by SNPStats software. No significant association between the three genetic variants of the NOS3 gene and infertility risk was determined comparing allele and genotype frequencies among group of patients diagnosed with azoospermia and the control group. Nevertheless, there was a significant positive association between 4a/4b and infertility in the group of males diagnosed with oligoasthenozoospermia, under overdominant genetic model. Our findings suggest that tandem repeat variant within intron 4 of the NOS3 gene is associated with an increased risk of infertility in men diagnosed with idiopathic oligoasthenozoospermia.Andrologia (2017): e1281

A search for candidate radio supernova remnants in the nearby irregular starburst galaxies NGC 4214 and NGC 4395

We present the results of a search for new candidate radio su­pernova remnants (SNRs) in the nearby starburst irregular galaxies NGC 4214 and NGC 4395 using archived radio observations made with the Very Large Array (VLA) at the wavelengths of 3.5 cm, 6 cm and 20 cm for NGC 4214 and 6 cm and 20 cm for NGC 4395. These observations were analyzed as part of our ongoing search for candidate radio SNRs in nearby galaxies: the goal of this search is to prepare a large sample of candidate radio SNRs for the purpose of a robust statistical study of the properties of these sources. Based on our analysis, we have confirmed the nonthermal nature of the discrete radio sources α and β in NGC 4214 and classify these sources as candidate radio SNRs based on their positional coincidences with HII regions in that galaxy. We have measured the flux densities of the two candidate radio SNRs at each wavelength and calculated corresponding spectral indices: we have also measured flux densities of two other discrete radio sources in these galaxies - ρ in NGC 4214 and #3 in NGC 4395 which we suspect to be additional candidate radio SNRs based on their positional coincidences with other HII regions in these galaxies. However, the radio data presently available for these sources can­not confirm such a classification and additional observations are needed. We have also calculated the radio luminosities Lradio at the wavelength of 20 cm for these two candidate radio SNRs as well as the corresponding values for the minimum total energy Emin required to power these radio sources via synchrotron emission and the corresponding magnetic field strength Bmin. We have compared our mean calculated values for these properties with the mean values for populations of candidate radio SNRs in other starburst galaxies: while the values for Lradio and Bmin are roughly comparable to the values seen in other starburst galaxies, the mean value for Emin is higher than the mean value of any other starburst galaxy. Finally, we include these two candidate radio SNRs in a discussion of the Σ − D relation for extragalactic candidate radio SNRs and find that these sources are located on the shallower end of the master Σ − D relation for all extragalactic SNRs as derived by Urošević et al.(2005).

Screening for the presence of biosynthetic genes for antimicrobial lipopeptides in natural isolates of Bacillus sp.

A collection of 205 natural isolates of Bacillus was tested for the presence of genes for biosynthesis of antimicrobial lipopeptides, iturin, surfactin, fengycin and bacillomycin D. For the detection of iturin producers by PCR screening, we used forward ITUP1-F and reverse ITUP2-R primers which are capable of detecting a 2-kb region that includes the intergenic sequence between the ituA and ituB genes. A 675-bp fragment from the gene sfp from B. subtilis encoding 4’-phosphopantetheinyl transferase involved in the biosynthesis of surfactin was targeted for amplification by using primers P17 and P18. Other two pairs of primers were BACC1F and BACC1R for bacillomycin D and FEND1F and FEND1R for potential fengycin producers, respectively. The results of the screening showed that the majority of tested strains had more than one biosynthetic operon, since 81% possessed the genes for bacillomycin D production, 54% for surfactin, 38% for iturin and 25% for fengycin production. [Projekat Ministarstva nauke Republike Srbije, br. 173026

Analysis of two single nucleotide polymorphisms at locus 17q12 associated with prostate cancer in Serbian population

Introduction & Objectives: Prostate cancer (PC) is the most prevalent type of cancer in males, comprising about 29% of all malignant tumors. Association with race, family and specific gene variants suggests strong role of genetics in prostate cancer etiology. Two nucleotide polymorphisms (SNPs) at 17q12 locus have been associated with the risk of developing prostate cancer in several previous genome-wide association studies. The correlation between the prostate cancer and rs7501939 and rs3760511 has already been confirmed in other populations, the goal of this study is to test whether it applies to Serbian population. material & methods: Analyses were done on 150 peripheral blood samples, taken from 100 patients diagnosed with prostate cancer whose prostate-specific antigen (PSA) serum levels and Gleason score were available and from 50 patients diagnosed with benign prostatic hyperplasia (BPH) , while the controls were 100 DNA swab samples taken from healthy individuals. The work proceeded through PCR amplification of two regions surrounding SNPs, restriction fragment length polymorphism (RFLP) analysis and random capillary gel electrophoresis of PCR samples from each SNP group as a control of RFLP analysis. The differences in genotype frequencies between case and control subjects were tested using a chisquare test with 1 degree of freedom. Results: The Chi-square test was used to determine if there is a statistical correlation between the SNP and PC and BPH. In the case of rs3760511 there was no correlation between the controls and the PC, but at the same time, there was a major statistical correlation between the BPH and PC samples, and also between BPH and the controls. The rs7501939 also showed no statistical correlation between the controls and PC samples, but showed correlation between controls and BPH as well as between BPH and PC samples. Also, there is no statistical correlation between the Gleason score, PSA levels and the SNP’s studied. Conclusions: The two SNP’s studied are not correlated to the PC in Serbian population.Poster Session 1 PROSTATE CANCER I Friday, 28 Octobe

Correlation between polymorphisms at promoter region of the NOS3 gene and prostate cancer in Serbian population

Objective: Prostate cancer (PC) is the most common malignant disease in men in the Western Hemisphere. The NOS3 has a role in vascular development, regulation of the vascular tone and tumor growth in PC. In previous studies, the -786 T > C polymorphism was found to be the most important promoter alteration of the NOS3 gene that may affect the PC progression. The purpose of this study was to evaluate 786 T > C, -764A > G, -714 G > T, -690 C > T and -649 G > A polymorphisms in the promoter region of NOS3 gene as genetic indicators of the relative risk of the PC occurrence in Serbian population. Method: In this study, we characterized these polymorphisms by PCR amplification, followed by capillary electrophoresis sequencing in the peripheral blood samples from 50 patients with PC, 50 benign hyperplasia patients and 50 individuals over 40 years of age who showed no clinical signs of any prostatic disease, that were used as controls. Results: Three of the analyzed polymorphisms (-764A > G, -714 G > T and -649 G > A) were not detected during this study. It is interesting to observe that when the -786 T > C polymorphism was present, -690 C > T polymorphism was also found. Conclusion: This study demonstrates no association between the -786 T > C polymorphism in the promoter of the NOS3 gene and the development of PC