Abstract
We present the discovery from the TESS mission of two giant planets transiting M-dwarf stars: TOI 4201 b and TOI 5344 b. We also provide precise radial velocity measurements and updated ...system parameters for three other M dwarfs with transiting giant planets: TOI 519, TOI 3629, and TOI 3714. We measure planetary masses of 0.525 ± 0.064
M
J
, 0.243 ± 0.020
M
J
, 0.689 ± 0.030
M
J
, 2.57 ± 0.15
M
J
, and 0.412±0.040
M
J
for TOI 519 b, TOI 3629 b, TOI 3714 b, TOI 4201 b, and TOI 5344 b, respectively. The corresponding stellar masses are 0.372 ± 0.018
M
☉
, 0.635 ± 0.032
M
☉
, 0.522 ± 0.028
M
☉
, 0.626 ± 0.033
M
☉
, and 0.612 ± 0.034
M
☉
. All five hosts have supersolar metallicities, providing further support for recent findings that, like for solar-type stars, close-in giant planets are preferentially found around metal-rich M-dwarf host stars. Finally, we describe a procedure for accounting for systematic errors in stellar evolution models when those models are included directly in fitting a transiting planet system.
The study of human fingernails as a possible dosimeter has continued to be of interest in the field of accident dosimetry because of its potential advantages. The present study aims to investigate ...the suitability of fingernails for the assessment of accidental exposure in medical facilities that use radiation for diagnosis or radiation therapy through the electron spin resonance (ESR) dosimetry technique. Relevant drying conditions, sample characteristics, and setup modifications were tested and compared among the samples of three different individuals. Results indicated that 1 h of sample drying inside a heat dryer sterilizer at 100 °C temperature showed good thermal stability of the ESR signals up to 30 days of postmeasurement. Another finding of this study was the effective approach in the signal stability for samples kept under vacuum storage condition with limited exposure to ambient light. While the samples from three different individuals showed unique dose–response curves after the X-ray irradiation, those were quite linear in the therapeutic dose range (up to 70 Gy). These results indicate that fingernails could be useful for the detection of unexpected significant exposure of patients and medical staff handling radiation or radiopharmaceuticals. Further investigations are desirable for standardization of the fingernail dosimetry in medical applications.
•A new setup modification for the fingernail ESR dosimetry was introduced.•Unique responses of fingernail ESR signals were found among three donors.•Fingernail ESR signals of each donor showed a good linearity of dose response up to 70 Gy.
Free radicals are formed when human fingernails are exposed to ionizing radiation. These free radicals can easily be detected using an electron spin resonance (ESR) technique. Although recent works ...have made important contributions to the development of ESR technique with fingernails, the effects of multiple irradiations on sensitivity of the radiation-induced signal and the influence of heat in the drying process of the samples have not been explored adequately. The researchers of this study have investigated the potential effects of multiple irradiations and exposure to heat on the ESR signals of fingernails. As a result, the slope of the dose-response curves decreased which reflected in the decrease of the sensitivity after multiple irradiations of the same fingernails to doses 35 Gy or 70 Gy of 137Cs γ-rays. Furthermore, it was observed that heat exposure considerably affected the visual shape and peak-to-peak intensity of the ESR spectra. Heating to temperatures above 80°C resulted in a noticeable increase to the intensity of the ESR spectra – generating a new ESR signal that overlapped with the native background signal in unirradiated fingernail samples. The results of this study suggested that some potential confounding effects need to be accounted carefully if ESR dosimetry of fingernails is to be applied in real radiation accident situations.
•Radiation sensitivity decreased after repeated irradiations of the same fingernails.•Heat exposure significantly changed the ESR spectra of unirradiated fingernails.•Heat-induced ESR signals were observed in fingernails after heating above 80°C.
► Morning commute equilibrium is unique if users choose car or bus, and departure time. ► The model recognizes that transit may take away street capacity for cars. ► System optimum is found ...recognizing that the population may include captive bus users. ► Time-dependent tolls, fares and bus headways that yield this system optimum are given. ► The system optimum and pricing results apply to networks as well as bottlenecks.
The morning commute problem for a single bottleneck, introduced in Vickrey (1969), is extended to model mode choice in an urban area with time-dependent demand. This extension recognizes that street space is shared by cars and public transit. It is assumed that transit is operated independently of traffic conditions, and that when it is operated it consumes a fixed amount of space.
As a first step, a single fixed-capacity bottleneck that can serve both cars and transit is studied. Commuters choose which mode to use and when to travel in order to minimize the generalized cost of their own trip. The transit agency chooses the headway and when to operate. Transit operations reduce the bottleneck’s capacity for cars by a fixed amount. The following results are shown for this type of bottleneck:
1.If the transit agency charges a fixed fare and operates at a given headway, and only when there is demand, then there is a unique user equilibrium.2.If the transit agency chooses its headway and time of operation for the common good, and users choose when to travel for the common good, then there is a system optimum solution with less cost and no queuing.3.Time-dependent tolls and fares that achieve this system optimum are given.
Finally, it is also shown that Results 2 and 3 apply to urban networks that serve a demand which is distributed in time and space, and which may include a population of captive transit riders. It is found that in many cases, additional transit service should be provided during a specified period in the rush.
Recoding–the repurposing of genetic codons–is a powerful strategy for enhancing genomes with functions not commonly found in nature. Here, we report computational design, synthesis, and progress ...toward assembly of a 3.97-megabase, 57-codon Escherichia coli genome in which all 62,214 instances of seven codons were replaced with synonymous alternatives across all protein-coding genes. We have validated 63% of recoded genes by individually testing 55 segments of 50 kilobases each. We observed that 91% of tested essential genes retained functionality with limited fitness effect. We demonstrate identification and correction of lethal design exceptions, only 13 of which were found in 2229 genes. This work underscores the feasibility of rewriting genomes and establishes a framework for large-scale design, assembly, troubleshooting, and phenotypic analysis of synthetic organisms.
Identifying the factors that influence taxi demand is very important for understanding where and when people use taxis. A large set of GPS data from New York City taxis is used along with ...demographic, socioeconomic, and employment data to identify the factors that drive taxi demand. A technique was developed to measure and map transit accessibility on the basis of transit access time (TAT) to understand the relationship between taxi use and transit service. The taxi data were categorized by pickups and drop-offs at different times of day. A multiple linear regression model was estimated for each hour of the day to model pickups and another to model drop-offs. Six important explanatory variables that influence taxi trips were identified: population, education, age, income, TAT, and employment. The influence of these factors on taxi pickups and drop-offs changed at different times of the day. The number of jobs in each industry sector was an indication of the types of economic activities occurring at a location, and in some sectors the number of jobs were strongly associated with taxi use. This study demonstrates the temporal and spatial variation of taxi demand and shows how transit accessibility and other factors affect it.
We present the discovery and characterization of two sub-Neptunes in close orbits, as well as a tentative outer planet of a similar size, orbiting TOI-1260 – a low metallicity K6 V dwarf star. ...Photometry from Transiting Exoplanet Survey Satellite(TESS) yields radii of R(b) = 2.33 ± 0.10 and R(c) = 2.82 ± 0.15 Rꚛ, and periods of 3.13 and 7.49 d for TOI-1260 b and TOI-1260 c, respectively. We combined the TESS data with a series of ground-based follow-up observations to characterize the planetary system. From HARPS-N high-precision radial velocities we obtain M(b) = 8.6(+1.4,−1.5) and M(c) = 11.8(+3.4,−3.2) Mꚛ. The star is moderately active with a complex activity pattern, which necessitated the use of Gaussian process regression for both the light-curve detrending and the radial velocity modelling, in the latter case guided by suitable activity indicators. We successfully disentangle the stellar-induced signal from the planetary signals, underlining the importance and usefulness of the Gaussian process approach. We test the system’s stability against atmospheric photoevaporation and find that the TOI-1260 planets are classic examples of the structure and composition ambiguity typical for the 2–3 Rꚛ range.
We show that expression of the microtubule depolymerizing kinesin KIF2C is induced by transformation of immortalized human bronchial epithelial cells (HBEC) by expression of K-Ras(G12V) and knockdown ...of p53. Further investigation demonstrates that this is due to the K-Ras/ERK1/2 MAPK pathway, as loss of p53 had little effect on KIF2C expression. In addition to KIF2C, we also found that the related kinesin KIF2A is modestly upregulated in this model system; both proteins are expressed more highly in many lung cancer cell lines compared to normal tissue. As a consequence of their depolymerizing activity, these kinesins increase dynamic instability of microtubules. Depletion of either of these kinesins impairs the ability of cells transformed with mutant K-Ras to migrate and invade matrigel. However, depletion of these kinesins does not reverse the epithelial to mesenchymal transition (EMT) caused by mutant K-Ras. Our studies indicate that increased expression of microtubule destabilizing factors can occur during oncogenesis to support enhanced migration and invasion of tumor cells.
Neurocysticercosis (NCC) is the most common helminthic infection of the human central nervous system. The antibody detection assay of choice is the enzyme-linked immunoelectrotransfer blot assay ...using lentil-lectin purified parasite antigens (LLGP-EITB, Western blot), an immunoassay with exceptional performance in clinical samples. However, its use is mainly restricted to a few research laboratories because the assay is labor-intensive and requires sophisticated equipment, expertise, and large amounts of parasite material for preparation of reagents. We report a new immunoprint assay (MAPIA) that overcomes most of these barriers. We initially compared the performance of five different antigen combinations in a subset of defined samples in the MAPIA format. After selecting the best-performing assay format (a combination of rGP50 + rT24H + sTs14 antigens), 148 archived serum samples were tested, including 40 from individuals with parenchymal NCC, 40 with subarachnoid NCC, and 68 healthy controls with no evidence of neurologic disease. MAPIA using three antigens (rGP50 + rT24H + sTs14) was highly sensitive and specific for detecting antibodies in NCC. It detected 39 out of 40 (97.5%) parenchymal NCC cases and 40/40 (100%) subarachnoid cases and was negative in 67 out of 68 (98.53%) negative samples. MAPIA using three recombinant and synthetic antigens is a simple and economical tool with a performance equivalent to the LLGP-EITB assay for the detection of specific antibodies to NCC. The MAPIA overcomes existing barriers to adoption of the EITG LLGP and is a candidate for worldwide use.
This study investigates the use of electron spin resonance (ESR) signals from human fingernails for retrospective dosimetry as part of radiation disaster response, focusing on the variabilities of ...individual responses to radiation. Samples of fingernails were collected from 7 adult donors (Asian type) and irradiated to 35 Gy and 70 Gy of gamma-rays from a Cs-137 source at a dose rate of 0.857 Gy/min. All irradiated fingernails were measured for 39 days with an X-band ESR spectrometer and stored in darkness inside the vacuum desiccator (30% humidity, 20°C) in between measurements at all times. All samples were harvested using one specific nail cutter and given no other special treatments. It was observed that the measured radiation-induced signals faded on about 10-12% after 1 day of exposure. Though the signal intensities showed a significant difference among the donors, stronger linearities in the dose responses were observed in the samples of younger donors. From the results obtained in this study, it is expected that fingernails would be a useful tool for retrospective dosimetry in case of an unexpected radiological accident or medical treatment error associated with exposure in therapeutic dose range, as far as the individual-based calibration curves were available. Further investigations will be made to clarify the reason for the different responses by using the fingernail samples taken from a greater number of donors of different ages and lifestyles.
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