Publisher: Cambridge University Press   (Total: 388 journals)

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Showing 1 - 200 of 388 Journals sorted alphabetically
Acta Neuropsychiatrica     Hybrid Journal   (Followers: 6, SJR: 0.733, CiteScore: 2)
Acta Numerica     Hybrid Journal   (Followers: 5, SJR: 6.709, CiteScore: 10)
Advances in Animal Biosciences     Full-text available via subscription   (Followers: 14)
Advances in Applied Mathematics and Mechanics     Full-text available via subscription   (Followers: 2, SJR: 0.441, CiteScore: 1)
Aeronautical J., The     Hybrid Journal   (Followers: 8)
Africa     Hybrid Journal   (Followers: 24, SJR: 0.582, CiteScore: 1)
African Studies Review     Full-text available via subscription   (Followers: 21, SJR: 0.437, CiteScore: 1)
Ageing & Society     Hybrid Journal   (Followers: 44, SJR: 0.756, CiteScore: 2)
Agricultural and Resource Economics Review     Open Access   (Followers: 7, SJR: 0.414, CiteScore: 1)
AI EDAM     Hybrid Journal   (Followers: 2, SJR: 0.375, CiteScore: 1)
AJIL Unbound     Open Access  
AJS Review     Full-text available via subscription   (Followers: 4, SJR: 0.128, CiteScore: 0)
American Political Science Review     Hybrid Journal   (Followers: 350, SJR: 5.587, CiteScore: 4)
Anatolian Studies     Full-text available via subscription   (Followers: 5, SJR: 0.528, CiteScore: 1)
Ancient Mesoamerica     Hybrid Journal   (Followers: 12, SJR: 0.478, CiteScore: 1)
Anglo-Saxon England     Hybrid Journal   (Followers: 36, SJR: 0.1, CiteScore: 0)
animal     Hybrid Journal   (Followers: 4, SJR: 0.842, CiteScore: 2)
Animal Health Research Reviews     Hybrid Journal   (Followers: 3, SJR: 0.69, CiteScore: 2)
Animal Science     Full-text available via subscription   (Followers: 10)
Annals of Actuarial Science     Full-text available via subscription   (Followers: 2)
Annual of the British School at Athens     Full-text available via subscription   (Followers: 16, SJR: 0.177, CiteScore: 0)
Annual Review of Applied Linguistics     Hybrid Journal   (Followers: 47, SJR: 3.223, CiteScore: 4)
Antarctic Science     Hybrid Journal   (Followers: 1, SJR: 0.643, CiteScore: 1)
Antichthon     Full-text available via subscription   (Followers: 3, SJR: 0.101, CiteScore: 0)
Antiquaries J., The     Full-text available via subscription   (Followers: 11, SJR: 0.106, CiteScore: 0)
Antiquity     Hybrid Journal   (Followers: 34)
ANZIAM J.     Open Access   (Followers: 1, SJR: 0.216, CiteScore: 0)
Applied Psycholinguistics     Hybrid Journal   (Followers: 28, SJR: 0.945, CiteScore: 2)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 8, SJR: 0.404, CiteScore: 2)
Arabic Sciences and Philosophy     Hybrid Journal   (Followers: 9, SJR: 0.101, CiteScore: 0)
Arbor Clinical Nutrition Updates     Full-text available via subscription   (Followers: 5)
Archaeological Dialogues     Hybrid Journal   (Followers: 35, SJR: 0.898, CiteScore: 1)
Archaeological Reports     Full-text available via subscription   (Followers: 5, SJR: 0.128, CiteScore: 0)
Architectural History     Full-text available via subscription  
arq: Architectural Research Quarterly     Hybrid Journal   (Followers: 7, SJR: 0.123, CiteScore: 0)
Art Libraries J.     Full-text available via subscription   (Followers: 2)
Asian J. of Comparative Law     Hybrid Journal   (Followers: 11, SJR: 0.129, CiteScore: 0)
Asian J. of Intl. Law     Hybrid Journal   (Followers: 17, SJR: 0.135, CiteScore: 0)
Asian J. of Law and Society     Hybrid Journal   (Followers: 7, SJR: 0.195, CiteScore: 0)
Astin Bulletin     Full-text available via subscription   (Followers: 1, SJR: 0.878, CiteScore: 1)
Australasian J. of Organisational Psychology     Hybrid Journal   (Followers: 9, SJR: 0.154, CiteScore: 1)
Australian J. of Environmental Education     Full-text available via subscription   (Followers: 9, SJR: 0.403, CiteScore: 1)
Australian J. of Indigenous Education, The     Full-text available via subscription   (Followers: 11, SJR: 0.26, CiteScore: 1)
Australian J. of Rehabilitation Counseling     Full-text available via subscription   (Followers: 6, SJR: 0.144, CiteScore: 0)
Austrian History Yearbook     Full-text available via subscription   (Followers: 11, SJR: 0.161, CiteScore: 0)
Behavioral and Brain Sciences     Hybrid Journal   (Followers: 38, SJR: 0.595, CiteScore: 1)
Behaviour Change     Full-text available via subscription   (Followers: 13, SJR: 0.508, CiteScore: 1)
Behavioural and Cognitive Psychotherapy     Hybrid Journal   (Followers: 192, SJR: 0.976, CiteScore: 2)
Bilingualism: Language and Cognition     Hybrid Journal   (Followers: 45, SJR: 1.446, CiteScore: 2)
Biofilms     Full-text available via subscription   (Followers: 2)
Bird Conservation Intl.     Hybrid Journal   (Followers: 25, SJR: 0.581, CiteScore: 1)
BJPsych Advances     Full-text available via subscription   (Followers: 57, SJR: 0.275, CiteScore: 0)
BJPsych Intl.     Open Access   (Followers: 2)
BJPsych Open     Open Access   (Followers: 3)
Brain Impairment     Full-text available via subscription   (Followers: 2, SJR: 0.321, CiteScore: 1)
Breast Cancer Online     Full-text available via subscription   (Followers: 6)
Britannia     Full-text available via subscription   (Followers: 12, SJR: 0.111, CiteScore: 0)
British Actuarial J.     Full-text available via subscription   (Followers: 1)
British Catholic History     Hybrid Journal   (Followers: 2, SJR: 0.133, CiteScore: 1)
British J. for the History of Science     Hybrid Journal   (Followers: 27, SJR: 0.235, CiteScore: 0)
British J. of Anaesthetic and Recovery Nursing     Full-text available via subscription   (Followers: 8)
British J. of Music Education     Hybrid Journal   (Followers: 24, SJR: 0.564, CiteScore: 1)
British J. Of Nutrition     Hybrid Journal   (Followers: 100, SJR: 1.612, CiteScore: 4)
British J. of Political Science     Hybrid Journal   (Followers: 237, SJR: 4.661, CiteScore: 4)
British J. of Psychiatry     Hybrid Journal   (Followers: 246, SJR: 2.844, CiteScore: 3)
Bulletin of Entomological Research     Hybrid Journal   (Followers: 13, SJR: 0.805, CiteScore: 2)
Bulletin of Symbolic Logic     Full-text available via subscription   (Followers: 2, SJR: 0.555, CiteScore: 1)
Bulletin of the Australian Mathematical Society     Full-text available via subscription   (Followers: 2, SJR: 0.44, CiteScore: 0)
Bulletin of the School of Oriental and African Studies     Hybrid Journal   (Followers: 21, SJR: 0.146, CiteScore: 0)
Business and Human Rights J.     Full-text available via subscription   (Followers: 4, SJR: 0.536, CiteScore: 1)
Business Ethics Quarterly     Full-text available via subscription   (Followers: 19, SJR: 1.098, CiteScore: 2)
Business History Review     Hybrid Journal   (Followers: 17, SJR: 0.347, CiteScore: 1)
Cambridge Archaeological J.     Hybrid Journal   (Followers: 171, SJR: 1.121, CiteScore: 1)
Cambridge Classical J.     Full-text available via subscription   (Followers: 24, SJR: 0.101, CiteScore: 0)
Cambridge J. of Postcolonial Literary Inquiry     Hybrid Journal   (Followers: 7)
Cambridge Law J.     Hybrid Journal   (Followers: 223, SJR: 0.213, CiteScore: 0)
Cambridge Opera J.     Hybrid Journal   (Followers: 4, SJR: 0.14, CiteScore: 0)
Cambridge Quarterly of Healthcare Ethics     Hybrid Journal   (Followers: 12, SJR: 0.299, CiteScore: 1)
Cambridge Yearbook of European Legal Studies     Full-text available via subscription   (Followers: 4)
Camden Fifth Series     Full-text available via subscription   (Followers: 3)
Canadian Entomologist     Hybrid Journal   (Followers: 5, SJR: 0.482, CiteScore: 1)
Canadian J. of Emergency Medicine     Hybrid Journal   (Followers: 13, SJR: 0.624, CiteScore: 1)
Canadian J. of Law & Jurisprudence     Full-text available via subscription   (Followers: 9, SJR: 0.237, CiteScore: 0)
Canadian J. of Law and Society     Hybrid Journal   (Followers: 22, SJR: 0.259, CiteScore: 1)
Canadian J. of Mathematics / J. canadien de mathématiques     Hybrid Journal  
Canadian J. of Neurological Sciences     Full-text available via subscription   (SJR: 0.549, CiteScore: 1)
Canadian J. of Political Science/Revue canadienne de science politique     Full-text available via subscription   (Followers: 25, SJR: 0.385, CiteScore: 1)
Canadian J. on Aging     Hybrid Journal   (Followers: 14, SJR: 0.426, CiteScore: 1)
Canadian Mathematical Bulletin     Hybrid Journal  
Canadian Yearbook of Intl. Law / Annuaire canadien de droit international     Full-text available via subscription   (Followers: 3)
Cardiology in the Young     Hybrid Journal   (Followers: 35, SJR: 0.372, CiteScore: 1)
Central European History     Full-text available via subscription   (Followers: 33, SJR: 0.159, CiteScore: 0)
Children Australia     Partially Free   (Followers: 2, SJR: 0.255, CiteScore: 0)
China Quarterly     Hybrid Journal   (Followers: 56, SJR: 2.289, CiteScore: 3)
Chinese J. of Agricultural Biotechnology     Full-text available via subscription   (Followers: 4)
Church History : Studies in Christianity and Culture     Full-text available via subscription   (Followers: 79, SJR: 0.106, CiteScore: 0)
Classical Quarterly     Full-text available via subscription   (Followers: 36, SJR: 0.204, CiteScore: 0)
Classical Review     Full-text available via subscription   (Followers: 29)
CNS Spectrums     Hybrid Journal   (Followers: 3, SJR: 1.391, CiteScore: 3)
Cognitive Behaviour Therapist     Hybrid Journal   (Followers: 14)
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4, SJR: 0.839, CiteScore: 1)
Communications in Computational Physics     Full-text available via subscription   (Followers: 3, SJR: 1.048, CiteScore: 2)
Comparative Studies in Society and History     Full-text available via subscription   (Followers: 51, SJR: 0.585, CiteScore: 1)
Compositio Mathematica     Full-text available via subscription   (SJR: 3.139, CiteScore: 1)
Contemporary European History     Hybrid Journal   (Followers: 37, SJR: 0.263, CiteScore: 1)
Continuity and Change     Hybrid Journal   (Followers: 12, SJR: 0.107, CiteScore: 0)
Dance Research J.     Full-text available via subscription   (Followers: 17, SJR: 0.211, CiteScore: 0)
Development and Psychopathology     Hybrid Journal   (Followers: 11, SJR: 2.068, CiteScore: 4)
Dialogue Canadian Philosophical Review/Revue canadienne de philosophie     Full-text available via subscription   (Followers: 5, SJR: 0.156, CiteScore: 0)
Diamond Light Source Proceedings     Full-text available via subscription   (Followers: 1)
Disaster Medicine and Public Health Preparedness     Hybrid Journal   (Followers: 15, SJR: 0.471, CiteScore: 1)
Du Bois Review: Social Science Research on Race     Full-text available via subscription   (Followers: 11, SJR: 0.561, CiteScore: 1)
Early China     Hybrid Journal   (Followers: 3)
Early Music History     Hybrid Journal   (Followers: 9, SJR: 0.101, CiteScore: 0)
Earth and Environmental Science Transactions of the Royal Society of Edinburgh     Hybrid Journal   (Followers: 5)
East Asian J. on Applied Mathematics     Full-text available via subscription   (SJR: 0.418, CiteScore: 1)
Ecclesiastical Law J.     Full-text available via subscription   (Followers: 6, SJR: 0.114, CiteScore: 0)
Econometric Theory     Hybrid Journal   (Followers: 21, SJR: 2.915, CiteScore: 1)
Economics and Philosophy     Hybrid Journal   (Followers: 21, SJR: 0.622, CiteScore: 1)
Edinburgh J. of Botany     Hybrid Journal   (SJR: 0.283, CiteScore: 1)
Educational and Developmental Psychologist     Full-text available via subscription   (Followers: 10, SJR: 0.146, CiteScore: 0)
Eighteenth-Century Music     Hybrid Journal   (Followers: 15, SJR: 0.113, CiteScore: 0)
English Language and Linguistics     Hybrid Journal   (Followers: 24, SJR: 0.52, CiteScore: 1)
English Profile J.     Hybrid Journal   (Followers: 2)
English Today     Hybrid Journal   (Followers: 13, SJR: 0.279, CiteScore: 0)
Enterprise & Society : The Intl. J. of Business History     Hybrid Journal   (Followers: 18, SJR: 0.245, CiteScore: 1)
Environment and Development Economics     Hybrid Journal   (Followers: 39, SJR: 0.617, CiteScore: 1)
Environmental Conservation     Hybrid Journal   (Followers: 61, SJR: 1.028, CiteScore: 2)
Environmental Practice     Full-text available via subscription   (Followers: 3, SJR: 0.145, CiteScore: 0)
Epidemiology & Infection     Open Access   (Followers: 22, SJR: 1.128, CiteScore: 2)
Epidemiology and Psychiatric Sciences     Open Access   (Followers: 4, SJR: 1.494, CiteScore: 2)
Episteme     Hybrid Journal   (Followers: 13, SJR: 0.756, CiteScore: 1)
Ergodic Theory and Dynamical Systems     Hybrid Journal   (Followers: 2, SJR: 1.193, CiteScore: 1)
Ethics & Intl. Affairs     Full-text available via subscription   (Followers: 18, SJR: 0.557, CiteScore: 1)
European Constitutional Law Review (EuConst)     Full-text available via subscription   (Followers: 40, SJR: 1.009, CiteScore: 1)
European J. of Applied Mathematics     Hybrid Journal   (SJR: 0.52, CiteScore: 1)
European J. of Intl. Security     Hybrid Journal   (Followers: 1)
European J. of Sociology     Hybrid Journal   (Followers: 38, SJR: 0.643, CiteScore: 1)
European Political Science Review     Hybrid Journal   (Followers: 28, SJR: 1.816, CiteScore: 2)
European Psychiatry     Open Access   (Followers: 14, SJR: 1.819, CiteScore: 3)
European Review     Hybrid Journal   (Followers: 19, SJR: 0.131, CiteScore: 0)
Evolutionary Human Sciences     Open Access   (Followers: 1)
Experimental Agriculture     Hybrid Journal   (Followers: 14, SJR: 0.542, CiteScore: 1)
Expert Reviews in Molecular Medicine     Hybrid Journal   (Followers: 1, SJR: 1.647, CiteScore: 4)
Fetal and Maternal Medicine Review     Hybrid Journal   (Followers: 6)
Financial History Review     Full-text available via subscription   (Followers: 15, SJR: 0.238, CiteScore: 1)
Foreign Policy Bulletin     Hybrid Journal   (Followers: 6)
Forum of Mathematics, Pi     Open Access   (Followers: 1)
Forum of Mathematics, Sigma     Open Access   (Followers: 1)
Genetics Research     Hybrid Journal   (Followers: 4, SJR: 0.483, CiteScore: 1)
Geological Magazine     Hybrid Journal   (Followers: 16, SJR: 0.966, CiteScore: 2)
Glasgow Mathematical J.     Full-text available via subscription   (SJR: 0.604, CiteScore: 0)
Global Constitutionalism     Hybrid Journal   (Followers: 17)
Global Mental Health     Open Access   (Followers: 9)
Global Sustainability     Open Access   (Followers: 1)
Government and Opposition     Full-text available via subscription   (Followers: 25, SJR: 0.965, CiteScore: 2)
Greece & Rome     Partially Free   (Followers: 30, SJR: 0.113, CiteScore: 0)
Hague J. on the Rule of Law     Full-text available via subscription   (Followers: 14, SJR: 0.271, CiteScore: 1)
Harvard Theological Review     Full-text available via subscription   (Followers: 79, SJR: 0.165, CiteScore: 0)
Health Economics, Policy and Law     Hybrid Journal   (Followers: 28, SJR: 0.745, CiteScore: 1)
Hegel Bulletin     Full-text available via subscription   (Followers: 2)
High Power Laser Science and Engineering     Open Access   (Followers: 4, SJR: 0.901, CiteScore: 3)
Historical J.     Hybrid Journal   (Followers: 42, SJR: 0.247, CiteScore: 1)
History in Africa     Full-text available via subscription   (Followers: 9)
Horizons     Partially Free   (Followers: 1, SJR: 0.129, CiteScore: 0)
Industrial and Organizational Psychology     Hybrid Journal   (Followers: 27, SJR: 0.916, CiteScore: 1)
Infection Control and Hospital Epidemiology     Full-text available via subscription   (Followers: 48, SJR: 1.97, CiteScore: 3)
Intl. & Comparative Law Quarterly     Full-text available via subscription   (Followers: 265, SJR: 0.369, CiteScore: 1)
Intl. Annals of Criminology     Full-text available via subscription  
Intl. J. of Asian Studies     Hybrid Journal   (Followers: 14, SJR: 0.143, CiteScore: 0)
Intl. J. of Astrobiology     Hybrid Journal   (Followers: 4, SJR: 0.548, CiteScore: 1)
Intl. J. of Cultural Property     Full-text available via subscription   (Followers: 14, SJR: 0.253, CiteScore: 1)
Intl. J. of Disability Management Research     Full-text available via subscription   (Followers: 10, SJR: 0.105, CiteScore: 0)
Intl. J. of Law in Context     Hybrid Journal   (Followers: 17, SJR: 0.275, CiteScore: 1)
Intl. J. of Legal Information     Full-text available via subscription   (Followers: 350)
Intl. J. of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 10, SJR: 0.184, CiteScore: 1)
Intl. J. of Middle East Studies     Hybrid Journal   (Followers: 72, SJR: 0.434, CiteScore: 0)
Intl. J. of Technology Assessment in Health Care     Hybrid Journal   (Followers: 14, SJR: 0.714, CiteScore: 1)
Intl. Labor and Working-Class History     Full-text available via subscription   (Followers: 14, SJR: 0.182, CiteScore: 0)
Intl. Organization     Full-text available via subscription   (Followers: 110, SJR: 8.527, CiteScore: 5)
Intl. Psychogeriatrics     Hybrid Journal   (Followers: 12, SJR: 1.048, CiteScore: 2)
Intl. Review of Social History     Full-text available via subscription   (Followers: 29, SJR: 0.315, CiteScore: 1)
Intl. Review of the Red Cross     Full-text available via subscription   (Followers: 12, SJR: 0.214, CiteScore: 0)
Intl. Theory: A J. of Intl. Politics, Law and Philosophy     Hybrid Journal   (Followers: 19, SJR: 2.293, CiteScore: 2)
Iraq     Full-text available via subscription   (Followers: 5)
Irish Historical Studies     Hybrid Journal   (Followers: 7, SJR: 0.103, CiteScore: 0)
Irish J. of Psychological Medicine     Hybrid Journal   (Followers: 2, SJR: 0.221, CiteScore: 0)
Israel Law Review     Hybrid Journal   (Followers: 2, SJR: 0.165, CiteScore: 0)
Italian Political Science Review / Rivista Italiana di Scienza Politica     Hybrid Journal   (Followers: 1)
Itinerario     Full-text available via subscription   (Followers: 11, SJR: 0.158, CiteScore: 0)
J. of African History     Hybrid Journal   (Followers: 23, SJR: 0.348, CiteScore: 1)
J. of African Law     Full-text available via subscription   (Followers: 2, SJR: 0.113, CiteScore: 0)
J. of Agricultural and Applied Economics     Open Access   (Followers: 4, SJR: 0.263, CiteScore: 1)
J. of Agricultural Science     Full-text available via subscription   (Followers: 9, SJR: 0.563, CiteScore: 1)
J. of American Studies     Hybrid Journal   (Followers: 21, SJR: 0.164, CiteScore: 0)
J. of Anglican Studies     Hybrid Journal   (Followers: 8, SJR: 0.101, CiteScore: 0)
J. of Applied Animal Nutrition     Hybrid Journal   (Followers: 4)
J. of Asian Studies     Full-text available via subscription   (Followers: 43, SJR: 0.591, CiteScore: 1)
J. of Benefit-Cost Analysis     Hybrid Journal   (Followers: 4)
J. of Biosocial Science     Hybrid Journal   (Followers: 5, SJR: 0.48, CiteScore: 1)

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Similar Journals
Journal Cover
International Journal of Astrobiology
Journal Prestige (SJR): 0.548
Citation Impact (citeScore): 1
Number of Followers: 4  
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1473-5504 - ISSN (Online) 1475-3006
Published by Cambridge University Press Homepage  [388 journals]
  • Deinococcus+radiodurans+exposed+to+simulated+space+conditions&rft.title=International+Journal+of+Astrobiology&rft.issn=1473-5504&,+Douglas+Galante&rft_id=info:doi/10.1017/S1473550419000211">Probing the response of Deinococcus radiodurans exposed to simulated space
    • Authors: Gabriel Guarany de Araujo; Fabio Rodrigues, Douglas Galante
      Pages: 203 - 209
      Abstract: The extremotolerant bacterium Deinococcus radiodurans is used as a model to explore the limits of life on Earth and beyond. In experiments performed in an ultra-high vacuum chamber with a vacuum ultraviolet (VUV) synchrotron beamline, this microorganism was exposed to conditions present on an extraterrestrial environment unprotected by an atmosphere, such as outside a spacecraft or on an asteroid, relevant in the context of planetary protection and panspermia hypothesis. Different methods were used to obtain the biologically relevant information from this investigation. Counting of colony forming units, the traditional approach for viability assessment, is limited to measuring the survival of the cells. For a more in-depth study of damage mechanisms at subcellular levels, specific molecular probes (propidium iodide and dihydrorhodamine 123) were applied and whole populations could be analysed, cell by cell, by flow cytometry. VUV radiation caused a substantial loss of viability, though only a fraction of the cells presented membrane damages even at the largest tested fluences. Additionally, intracellular oxidative stress was also detected upon exposure. These results point to significant VUV inactivating effects extending beyond the cells' outermost structures, in contrast to a more superficial role that could be expected due to the highly interacting nature of this radiation range. Nevertheless, it was observed that microscopic-level shading sufficed to allow the persistence of a small surviving subpopulation for the longer expositions. This study contributes to unveiling the response of biological systems under space conditions, assessing not just cell viability but also the mechanisms that lead to inactivation.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000211
      Issue No: Vol. 19, No. 3 (2020)
  • Photosynthesis on exoplanets and exomoons from reflected light
    • Authors: Manasvi Lingam; Abraham Loeb
      Pages: 210 - 219
      Abstract: Photosynthesis offers a convenient means of sustaining biospheres. We quantify the constraints for photosynthesis to be functional on the permanent nightside of tidally locked rocky exoplanets via reflected light from their exomoons. We show that the exomoons must be at least half the size of Earth's moon in order for conventional oxygenic photosynthesis to operate. This scenario of photosynthesis is unlikely for exoplanets around late-type M-dwarfs due to the low likelihood of large exomoons and their orbital instability over long timescales. Subsequently, we investigate the prospects for photosynthesis on habitable exomoons via reflected light from the giant planets that they orbit. Our analysis indicates that such photosynthetic biospheres are potentially sustainable on these moons except those around late-type M-dwarfs. We conclude our analysis by delineating certain physiological and biochemical features of photosynthesis and other carbon fixation pathways, and the likelihood of their evolution on habitable planets and moons.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000247
      Issue No: Vol. 19, No. 3 (2020)
  • On the interstellar Von Neumann micro self-reproducing probes
    • Authors: Z. Osmanov
      Pages: 220 - 223
      Abstract: In this paper we consider efficiency of self-reproducing extraterrestrial Von-Neumann micro scale robots and analyse the observational characteristics. By examining the natural scenario of moving in the HII clouds, it has been found that the timescale of replication might be several years and even less – making the process of observation quite promising. We have shown that by encountering the interstellar protons the probes might be visible at least in the infrared energy band and the corresponding luminosities might reach enormous values.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000259
      Issue No: Vol. 19, No. 3 (2020)
  • Effect of γ-radiation on adenine dissolved in distilled water, saline
           solutions and artificial seawater resembling that of 4.0 billion years ago
    • Authors: João Paulo T. Baú; Sául A. Villafañe-Barajas, Alicia Negrón-Mendoza, María Colín-García, Dimas A. M. Zaia
      Pages: 224 - 236
      Abstract: In this work, the effect of γ-radiation on the decomposition of adenine dissolved in distilled water, saline solutions and artificial seawater was studied. As the composition of the major cations and anions of artificial seawater probably better resembles the composition of seawater on the Earth 4.0 billion years ago, this seawater was named artificial seawater 4.0 Ga. The main finding in this work is that artificial seawater 4.0 Ga demonstrated a better protective effect of adenine against γ-radiation. In addition, artificial seawater 4.0 Ga showed that adenine had no changes in pH after radiation exposure and the minor radiation-chemical yield G. The radiolysis of adenine promoted modifications in Fourier-transform infrared spectra. The deconvolution of some bands demonstrated the formation of a new frequency at 1713 cm−1. High performance liquid chromatography-mass detected a product of decomposition with 151 atomic units. Using the geometry optimization and simulated vibrational spectra it was possible to show that the main species formed are hydroxyl and oxide modified adenine. The data point to the formation of hydroxyl-adenine and adenine Nx-oxide. These products have biological relevance and could be available for chemical evolution.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000272
      Issue No: Vol. 19, No. 3 (2020)
  • Nine axes of merit for technosignature searches
    • Authors: Sofia Z. Sheikh
      Pages: 237 - 243
      Abstract: It can be difficult to develop an effective and balanced search strategy in SETI, especially from a funding perspective, given the diverse methodologies and myriad orthogonal proposals for the best technosignatures. Here I propose a framework to compare the relative advantages and disadvantages of various proposed technosignatures based on nine ‘axes of merit’. This framework was first developed at the NASA Technosignatures Workshop in Houston in 2018 and published in that report. I give the definition and rationale behind the nine axes as well as the history of each axis in the SETI and technosignature literature. These axes are then applied to three classes of technosignature searches as an illustration of their use. An open-source software tool is available to allow technosignature researchers to make their own version of the figure.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000284
      Issue No: Vol. 19, No. 3 (2020)
  • The search for microbial Martian life and American Buddhist ethics
    • Authors: Daniel Capper
      Pages: 244 - 252
      Abstract: Multiple searches hunt for extraterrestrial life, yet the ethics of such searches in terms of fossil and possible extant life on Mars have not been sufficiently delineated. In response, in this essay, I propose a tripartite ethic for searches for microbial Martian life that consists of default non-harm towards potential living beings, default non-harm to the habitats of potential living beings, but also responsible, restrained scientific harvesting of some microbes in limited transgression of these default non-harm modes. Although this multifaceted ethic remains secular and hence adaptable to space research settings, it arises from both a qualitative analysis of authoritative Buddhist scriptural ethics as well as the quantified ethnographic survey voices of contemporary American Buddhists. The resulting tripartite ethic, while developed for Mars, contains ramifications for the study of microbes on Earth and further retains application to other research locations in our Solar system.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000296
      Issue No: Vol. 19, No. 3 (2020)
  • Stability of α-ketoglutaric acid simulating an impact-generated
           hydrothermal system: implications for prebiotic chemistry studies
    • Authors: L. Ramírez-Vázquez; A. Negrón-Mendoza
      Pages: 253 - 259
      Abstract: Life originated on Earth possibly as a physicochemical process; thus, geological environments and their hypothetical characteristics on early Earth are essential for chemical evolution studies. Also, it is necessary to consider the energy sources that were available in the past and the components that could have contributed to promote chemical reactions. It has been proposed that the components could have been mineral surfaces. The aim of this work is to determine the possible role of mineral surfaces on chemical evolution, and to study of the stability of relevant molecules for metabolism, such as α-ketoglutaric acid (α-keto acid, Krebs cycle participant), using ionizing radiation and thermal energy as energy sources and mineral surfaces to promote chemical reactions. Preliminary results show α-ketoglutaric acid can be relatively stable at the simulated conditions of an impact-generated hydrothermal system; thus, those systems might have been plausible environments for chemical evolution on Earth.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000302
      Issue No: Vol. 19, No. 3 (2020)
  • Exporting terrestrial life out of the Solar System with gravitational
           slingshots of Earthgrazing bodies
    • Authors: Amir Siraj; Abraham Loeb
      Pages: 260 - 263
      Abstract: Exporting terrestrial life out of the Solar System requires a process that both embeds microbes in boulders and ejects those boulders out of the Solar System. We explore the possibility that Earthgrazing long-period comets (LPCs) and interstellar objects (ISOs) could export life from Earth by collecting microbes from the atmosphere and receiving a gravitational slingshot effect from the Earth. We estimate the total number of exportation events over the lifetime of the Earth to be ~1–10 for LPCs and ~1–50 for ISOs. If life existed above an altitude of 100 km, then the number is dramatically increased up to ~105 exportation events over Earth's lifetime.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000314
      Issue No: Vol. 19, No. 3 (2020)
  • Earth-Like:+an+education+&+outreach+tool+for+exploring+the+diversity+of+planets+like+our+own&rft.title=International+Journal+of+Astrobiology&rft.issn=1473-5504&,+Nicholas+Guttenberg,+Julien+Foriel&rft_id=info:doi/10.1017/S1473550419000326">Earth-Like: an education & outreach tool for exploring the diversity of
           planets like our own
    • Authors: Elizabeth J. Tasker; Kana Ishimaru, Nicholas Guttenberg, Julien Foriel
      Pages: 264 - 275
      Abstract: Earth-Like is an interactive website and twitter bot that allows users to explore changes in the average global surface temperature of an Earth-like planet due to variations in the surface oceans and emerged land coverage, rate of volcanism (degassing) and the level of the received solar radiation. The temperature is calculated using a simple carbon–silicate cycle model to change the level of CO2 in the atmosphere based on the chosen parameters. The model can achieve a temperature range exceeding −100°C to 100°C by varying all three parameters, including freeze-thaw cycles for a planet with our present-day volcanism rate and emerged land fraction situated at the outer edge of the habitable zone. To increase engagement, the planet is visualized by using a neural network to render an animated globe, based on the calculated average surface temperature and chosen values for land fraction and volcanism. The website and bot can be found at and on twitter as @earthlikeworld. Initial feedback via a user survey suggested that Earth-Like is effective at demonstrating that minor changes in planetary properties can strongly impact the surface environment. The goal of the project is to increase understanding of the challenges we face in finding another habitable planet due to the likely diversity of conditions on rocky worlds within our Galaxy.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000326
      Issue No: Vol. 19, No. 3 (2020)
  • Acceleration of amino acid racemization by isovaline: possible
           implications for homochirality and biosignature search
    • Authors: Stefan Fox; Annika Gspandl, Franziska M. Wenng
      Pages: 276 - 282
      Abstract: In nature, abiotically formed amino acids are usually racemic. However, this is not true for the α,α-dialkyl amino acid isovaline (Iva), which has an L-enantiomeric excess in some specimens of carbonaceous meteorites. On the early Earth and Mars, such meteorites were sources of amino acids, including Iva. Therefore, a connection may exist between the possible chiral influence of non-racemic Iva and the origin of biological homochirality. On the surface of a young terrestrial planet, amino acids can be chemically altered in many ways. For example, high temperatures from geothermal heating can lead to racemization. Four billion years ago, active volcanism and volcanic islands provided suitable conditions for such reactions and perhaps even for early microbial life on Earth. In the current study, we investigated the influence of D- and L-Iva on the thermal racemization of L-alanine (L-Ala) and L-2-aminobutyric acid (L-Abu) in a simulated hot volcanic environment. The amino acids were intercalated in the clay mineral calcium montmorillonite (SAz-1). While Iva was resistant to racemization, partial racemization was observed for Ala and Abu after 8 weeks at 150°C. The experimental results – for example, accelerated racemization in the presence of Iva and different influences of the Iva enantiomers – suggest that the amino acid molecules interacted with each other, possibly in hydrogen-bonded dimers. Accelerated racemization of amino acids could have been an obstacle to the development of homochirality. Besides, it is also detrimental to the use of homochirality as a biosignature, for example, in the search for microbial life on Mars.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550420000014
      Issue No: Vol. 19, No. 3 (2020)
  • Why should geological criteria used on Earth not be valid also for
           Mars' Evidence of possible microbialites and algae in extinct Martian
    • Authors: Vincenzo Rizzo
      Pages: 283 - 294
      Abstract: During the Noachian period, 4.1-3.7 Gys ago, the Martian environment was moderately similar to the one on present Earth. Liquid water was widespread in a neutral environment, volcanic activity and heat flow more vigorous, and atmospheric pressure and temperature were higher than today. These conditions may have favoured the spread of life on the surface of Mars. The recognition that different planets and moons share rocky material cast in space by meteoroid impact entails that life creation is not necessary for each single planetary body, but could travel through the Solar system on board of rock fragments. Studies conducted on the past forms of Martian life have already highlighted possible positive matches with microbialite-like structures, referable to the geo-environmental conditions in the Noachian and Hesperian. However, by necessity, these studies are on predominantly micro and meso-scopic scale structures and doubts arise as to their attribution to the biogenic world. We suggest that in the identification of Martian life, we are currently in a position similar to the one of Kalkowsky who in 1908, based solely on morphological and sedimentological arguments, hypothesized the (now accepted) view of the biotic origin of stromatolites. Our analysis of thousands of images from Spirit, Opportunity and Curiosity has provided a selection of images of ring-shaped, domal and coniform macrostructures that resemble terrestrial microbialites such as the ring-shaped stromatolites of Lake Thetis, and stacked cones reminiscent of the group of terrestrial Conophyton. Notably, the latter were detected by Curiosity in the mudstone known as ‘Sheepbed’, the same outcrop where past organic molecules have been detected and where the occurrence of microbial-induced sedimentary structures (MISS) and of many more microbialitic micro, meso and macrostructures has already been hypothesized. Some of the structures discussed in this work are so complex that alternative biological hypotheses can be formulated as possible algae. Alternate, non-abiotic explanations are examined but we find difficult to explain some of such structures in the context of normal sedimentary processes, both syngenetic or epigenetic.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550420000026
      Issue No: Vol. 19, No. 3 (2020)
  • Will recent advances in AI result in a paradigm shift in Astrobiology and
    • Authors: Joe Gale; Amri Wandel, Hugh Hill
      Pages: 295 - 298
      Abstract: The steady advances in computer performance and in programming raise the concern that the ability of computers would overtake that of the human brain, an occurrence termed ‘the Singularity’. While comparing the size of the human brain and the advance in computer capacity, the Singularity has been estimated to occur within a few decades although the capacity of conventional computers may reach its limits in the near future. However, in the last few years, there have been rapid advances in artificial intelligence. There are already programs that carry out pattern recognition and self-learning which, at least in limited fields such as chess and other games, are superior to the best human players. Furthermore, the quantum computing revolution, which is expected to vastly increase computer capacities, is already on our doorstep. It now seems inevitable that the Singularity will arrive within the foreseeable future. Biological life, on Earth and on extraterrestrial planets and their satellites, may continue as before, but humanity could be ‘replaced’ by computers. Older and more advanced intelligent life forms, possibly evolved elsewhere in the Universe, may have passed their Singularity a long time ago. Post Singularity life would probably be based not on biochemical reactions but on electronics. Their communication may use effects such as quantum entanglement and be undetectable to us. This may explain the Fermi paradox or at least the ‘Big Silence’ problem in SETI.
      PubDate: 2020-06-01T00:00:00.000Z
      DOI: 10.1017/S1473550419000260
      Issue No: Vol. 19, No. 3 (2020)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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