23 research outputs found
Exoplanets and SETI
The discovery of exoplanets has both focused and expanded the search for
extraterrestrial intelligence. The consideration of Earth as an exoplanet, the
knowledge of the orbital parameters of individual exoplanets, and our new
understanding of the prevalence of exoplanets throughout the galaxy have all
altered the search strategies of communication SETI efforts, by inspiring new
"Schelling points" (i.e. optimal search strategies for beacons). Future efforts
to characterize individual planets photometrically and spectroscopically, with
imaging and via transit, will also allow for searches for a variety of
technosignatures on their surfaces, in their atmospheres, and in orbit around
them. In the near-term, searches for new planetary systems might even turn up
free-floating megastructures.Comment: 9 page invited review. v2 adds some references and v3 has other minor
additions and modification
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The First Post-Kepler Brightness Dips of KIC 8462852
We present a photometric detection of the first brightness dips of the unique
variable star KIC 8462852 since the end of the Kepler space mission in 2013
May. Our regular photometric surveillance started in October 2015, and a
sequence of dipping began in 2017 May continuing on through the end of 2017,
when the star was no longer visible from Earth. We distinguish four main 1-2.5%
dips, named "Elsie," "Celeste," "Skara Brae," and "Angkor", which persist on
timescales from several days to weeks. Our main results so far are: (i) there
are no apparent changes of the stellar spectrum or polarization during the
dips; (ii) the multiband photometry of the dips shows differential reddening
favoring non-grey extinction. Therefore, our data are inconsistent with dip
models that invoke optically thick material, but rather they are in-line with
predictions for an occulter consisting primarily of ordinary dust, where much
of the material must be optically thin with a size scale <<1um, and may also be
consistent with models invoking variations intrinsic to the stellar
photosphere. Notably, our data do not place constraints on the color of the
longer-term "secular" dimming, which may be caused by independent processes, or
probe different regimes of a single process
The Application of Autocorrelation SETI Search Techniques in an ATA Survey
We report a novel radio autocorrelation search for extraterrestrial intelligence. For selected frequencies across the terrestrial microwave window (1-10 GHz), observations were conducted at the Allen Telescope Array to identify artificial non-sinusoidal periodic signals with radio bandwidths greater than 4 Hz, which are capable of carrying substantial messages with symbol rates from 4 to 106 Hz. Out of 243 observations, about half (101) were directed toward sources with known continuum flux >∼1 Jy over the sampled bandwidth (quasars, pulsars, supernova remnants, and masers), based on the hypothesis that they might harbor heretofore undiscovered natural or artificial repetitive, phase or frequency modulation. The rest of the observations were directed mostly toward exoplanet stars with no previously discovered continuum flux. No signals attributable to extraterrestrial technology were found in this study. We conclude that the maximum probability that future observations like the ones described here will reveal repetitively modulated emissions is less than 5% for continuum sources and exoplanets alike. The paper concludes by describing a new approach to expanding this survey to many more targets and much greater sensitivity using archived data from interferometers all over the world
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The Application of Autocorrelation SETI Search Techniques in an ATA Survey
We report a novel radio autocorrelation search for extraterrestrial intelligence. For selected frequencies across the terrestrial microwave window (1-10 GHz), observations were conducted at the Allen Telescope Array to identify artificial non-sinusoidal periodic signals with radio bandwidths greater than 4 Hz, which are capable of carrying substantial messages with symbol rates from 4 to 106 Hz. Out of 243 observations, about half (101) were directed toward sources with known continuum flux >∼1 Jy over the sampled bandwidth (quasars, pulsars, supernova remnants, and masers), based on the hypothesis that they might harbor heretofore undiscovered natural or artificial repetitive, phase or frequency modulation. The rest of the observations were directed mostly toward exoplanet stars with no previously discovered continuum flux. No signals attributable to extraterrestrial technology were found in this study. We conclude that the maximum probability that future observations like the ones described here will reveal repetitively modulated emissions is less than 5% for continuum sources and exoplanets alike. The paper concludes by describing a new approach to expanding this survey to many more targets and much greater sensitivity using archived data from interferometers all over the world
Creatine supplementation with specific view to exercise/sports performance: An update
Creatine is one of the most popular and widely researched natural supplements. The majority of studies have
focused on the effects of creatine monohydrate on performance and health; however, many other forms of
creatine exist and are commercially available in the sports nutrition/supplement market. Regardless of the form,
supplementation with creatine has regularly shown to increase strength, fat free mass, and muscle morphology
with concurrent heavy resistance training more than resistance training alone. Creatine may be of benefit in other
modes of exercise such as high-intensity sprints or endurance training. However, it appears that the effects of
creatine diminish as the length of time spent exercising increases. Even though not all individuals respond similarly
to creatine supplementation, it is generally accepted that its supplementation increases creatine storage and
promotes a faster regeneration of adenosine triphosphate between high intensity exercises. These improved
outcomes will increase performance and promote greater training adaptations. More recent research suggests that
creatine supplementation in amounts of 0.1 g/kg of body weight combined with resistance training improves
training adaptations at a cellular and sub-cellular level. Finally, although presently ingesting creatine as an oral
supplement is considered safe and ethical, the perception of safety cannot be guaranteed, especially when
administered for long period of time to different populations (athletes, sedentary, patient, active, young or elderly)