Non-Standard Errors

In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty: Non-standard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for better reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants

Astronaut\u27s organ doses inferred from measurements in a human phantom outside the international space station

Space radiation hazards are recognized as a key concern for human space flight. For long-term interplanetary missions, they constitute a potentially limiting factor since current protection limits for low-Earth orbit missions may be approached or even exceeded. In such a situation, an accurate risk assessment requires knowledge of equivalent doses in critical radiosensitive organs rather than only skin doses or ambient doses from area monitoring. To achieve this, the MATROSHKA experiment uses a human phantom torso equipped with dedicated detector systems. We measured for the first time the doses from the diverse components of ionizing space radiation at the surface and at different locations inside the phantom positioned outside the International Space Station, thereby simulating an extravehicular activity of an astronaut. The relationships between the skin and organ absorbed doses obtained in such an exposure show a steep gradient between the doses in the uppermost layer of the skin and the deep organs with a ratio close to 20. This decrease due to the body self-shielding and a concomitant increase of the radiation quality factor by 1.7 highlight the complexities of an adequate dosimetry of space radiation. The depth-dose distributions established by MATROSHKA serve as benchmarks for space radiation models and radiation transport calculations that are needed for mission planning

Bacterial spore resistance to major components of the galactic

The results indicate that there are similar- partly identical - responses of spores tovarious DNA damaging stresses point to the existence of a general built-in -transcriptional germination program in spores with key transcriptional events ascheckpoints for ensuring DNA restoration and integrity after radiation exposure.11th European Workshop on Astrobiology in Cologne (Köln), July 11th - 14th, 201

Out-of-field dose studies with an anthropomorphic phantom: comparison of X-rays and particle therapy treatments

Background and purpose: Characterization of the out-of-field dose profile following irradiation of the target with a 3D treatment plan delivered with modern techniques.Methods: An anthropomorphic RANDO phantom was irradiated with a treatment plan designed for a simulated 5x2x5 cm3tumor volume located in the center of the head. The experiment was repeated withall most common radiation treatment types (photons, protons and carbon ions) and delivery techniques(Intensity Modulated Radiation Therapy, passive modulation and spot scanning). The measurementswere performed with active diamond detector and passive thermoluminescence (TLD) detectors to investigate the out-of-field dose both inside and outside the phantom.Results: The highest out-of-field dose values both on the surface and inside the phantom were measuredduring the treatment with 25 MV photons. In the proximity of the Planned Target Volume (PTV), the lowest lateral dose profile was observed for passively modulated protons mainly because of the presence ofthe collimator in combination with the chosen volume shape. In the far out-of-field region (above100 mm from the PTV), passively modulated ions were characterized by a less pronounced dose falloff in comparison with scanned beams. Overall, the treatment with scanned carbon ions delivered thelowest dose outside the target volume.Conclusions: For the selected PTV, the use of the collimator in proton therapy drastically reduced the dosedeposited by ions or photons nearby the tumor. Scanning modulation represents the optimal techniquefor achieving the highest dose reduction far-out-of-field

Astrobiological aspects of the mutagenesis of cosmic radiation on bacterial spores

Based on their unique resistance to various space parameters, Bacillus endospores are one of the27 model systems used for astrobiological studies. In this study, spores of B. subtilis were used to study28 the effects of galactic cosmic radiation on spore survival and induced mutagenesis. In interplanetary29 space, outside Earths protective magnetic field, spore-containing rocks would be exposed to30 bombardment by high-energy charged particle radiation from galactic sources and from the sun,31 consisting of photons (X-rays, gamma-rays), protons, electrons and heavy, high-energy charged (HZE)32 particles. B. subtilis spores were irradiated with X-rays and accelerated heavy ions (Helium, Carbon,33 Silicon and Iron) in the linear energy transfer (LET) range of 2 to 200 keV/um. Spore survival and therate of the induced mutations to rifampicin-resistance (RifR34 ) depended on the LET of the applied35 species of ions and radiation, whereas the exposure to high-energy charged particles, e.g. iron ions, ledto a low level of spore survival and increased frequency of mutation to RifR 36 compared to low-energycharged particles and X-rays. Twenty-one RifR 37 mutant spores were isolated from X-ray and heavy ionirradiatedsamples. Nucleotide sequencing located the RifR 38 mutations in the rpoB gene encoding the beta-39 subunit of RNA polymerase. Most mutations were primarily found in Cluster I and were predicted to40 result in amino acid changes at residues Q469L, A478V, and H482P/Y. Four previously undescribed41 alleles in B. subtilis rpoB were isolated; L467P, R484P, and A488P in Cluster I and H507R in thespacer between Clusters I and II. The spectrum of RifR 42 mutations arising from spores exposed to43 components of galactic cosmic radiation is distinctly different from those of spores exposed to44 simulated space vacuum and Martian conditions

Role of the Nfo and ExoA Apurinic/Apyrimidinic Endonucleases in Radiaiton Resistance and Radiation-Induced Mutagenesis of Bacillus subtilis Spores

The roles of DNA repair by apurinic/apyrimidinic (AP) endonucleases alone, and together with DNA protection by alpha/beta type small acid-soluble spore proteins (SASP), in Bacillus subtilis spore resistance to different types of radiation have been studied. Spores lacking both AP endonucleases (Nfo and ExoA) and major SASPwere significantly more sensitive to 254-nm UV-C, environmental UV (>280 nm), X-ray exposure, and highenergy charged (HZE)-particle bombardment and had elevated mutation frequencies compared to those of wild-type spores and spores lacking only one or both AP endonucleases or major SASP. These findings further implicate AP endonucleases and alpha/beta type SASP in repair and protection, respectively, of spore DNA against effects of UV and ionizing radiation

Role of the major, small, acid-soluble spore proteins and spore-specific and universal DNA repair mechanisms in resistance of Bacillus subtilis spores to ionizing radiation from X rays and high energy charged-particle bombardment

The role of various DNA repair mechanisms [non-homologous end joining (NHEJ), homologous recombination (HR), spore photoproduct lyase (SP lyase) and DNA polymerase I] and major small, acid-soluble spore proteins (&#61537;&#61487;&#61538;-type SASP) was studied in the Bacillus subtilis spore resistance against exposure to accelerated heavy ions (Helium, Argon and Iron) and X-rays. Spores of wild-type B. subtilis strain 168, a mutant lacking &#61537;&#61487;&#61538;-type SASP, (encoded by sspA sspB), and six DNA repair-deficient (polA, recA, splB, ykoU, ykoV and ykoU ykoV) strains were exposed to X-rays and the three kinds of heavy ions [the so-called high energy charged (HZE) particles] in a linear energy transfer (LET) range of 2 to 200 keV/&micro;m. The sporicidal effectiveness increased in the order X-rays < Helium < Argon < Iron irradiation. NHEJ-mutant spores deficient in ykoU (an ATP-dependent DNA ligase), ykoV (a Ku-like DNA-binding protein), the double mutant strain ykoU ykoV and the &#61537;&#61487;&#61538;-type SASP-deficient spores were significantly more sensitive to HZE particle bombardment and X-ray irradiation compared to the recA, polA, splB and wild-type spores. These results indicate that NHEJ provides an efficient pathway during spore germination for repair of DNA double-strand breaks induced by HZE particles. In addition, the loss of the &#61537;&#61487;&#61538;-type SASP leads to a significant radiosensitivity to ionizing radiation, implicating the essential function of these spore proteins as protectants of spore DNA to ionizing radiation and heavy particle damage, in addition to their known roles in UV, heat and peroxide stress protection