Spatiotemporal patterns of gene expression are fundamental to every developmental program. The resulting macroscopic domains have been mainly characterized by their levels of gene products 1–3. ...However, the establishment of such patterns results from differences in the dynamics of microscopic events in individual cells such as transcription. It is unclear how these microscopic decisions lead to macroscopic patterns, as measurements in fixed tissue cannot access the underlying transcriptional dynamics 4–7. In vivo transcriptional dynamics have long been approached in single-celled organisms 8–12, but never in a multicellular developmental context. Here, we directly address how boundaries of gene expression emerge in the Drosophila embryo by measuring the absolute number of actively transcribing polymerases in real time in individual nuclei. Specifically, we show that the formation of a boundary cannot be quantitatively explained by the rate of mRNA production in each cell, but instead requires amplification of the dynamic range of the expression boundary. This amplification is accomplished by nuclei randomly adopting active or inactive states of transcription, leading to a collective effect where the fraction of active nuclei is modulated in space. Thus, developmental patterns are not just the consequence of reproducible transcriptional dynamics in individual nuclei, but are the result of averaging expression over space and time.
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•In vivo dynamics of transcriptional activity in Drosophila embryos is revealed•Formation of expression pattern is reconstructed from activity in individual nuclei•Control of polymerase loading rate only partially explains pattern boundary•Binary stochastic states of activity of individual nuclei are necessary
At the end of inflation, the inflaton field decays into an initially nonthermal population of relativistic particles which eventually thermalize. We consider the production of dark matter via ...freeze-in from this relativistic plasma, focusing on the prethermal phase. We find that for a production cross section σ(E)∼En with n>2, the present dark matter abundance is produced during the prethermal phase of its progenitors. For n≤2, entropy production during reheating makes the nonthermal contribution to the present dark matter abundance subdominant compared to that produced thermally. As specific examples, we verify that the nonthermal contribution is irrelevant for gravitino production in low scale supersymmetric models (n=0) and is dominant for gravitino production in high scale supersymmetry models (n=6).
We perform a systematic analysis of dark matter production during postinflationary reheating. Following the period of exponential expansion, the inflaton begins a period of damped oscillations as it ...decays. These oscillations and the evolution of temperature of the thermalized decay products depend on the shape of the inflaton potential V ( Φ ) . We consider potentials of the form, Φk. Standard matter-dominated oscillations occur for k = 2 . In general, the production of dark matter may depend on either (or both) the maximum temperature after inflation, or the reheating temperature, where the latter is defined when the Universe becomes radiation dominated. We show that dark matter production is sensitive to the inflaton potential and depends heavily on the maximum temperature when k > 2. We also consider the production of dark matter with masses larger than the reheating temperature.
In the first stages of inflationary reheating, the temperature of the radiation produced by inflaton decays is typically higher than the commonly defined reheating temperature TRH∼(ΓϕMP)1/2 where Γϕ ...is the inflaton decay rate. We consider the effect of particle production at temperatures at or near the maximum temperature attained during reheating. We show that the impact of this early production on the final particle abundance depends strongly on the temperature dependence of the production cross section. For ⟨σv⟩∼Tn/Mn+2, and for n<6, any particle produced at Tmax is diluted by the later generation of entropy near TRH. This applies to cases such as gravitino production in low scale supersymmetric models (n=0) or NETDM models of dark matter (n=2). However, for n≥6 the net abundance of particles produced during reheating is enhanced by over an order of magnitude, dominating over the dilution effect. This applies, for instance to gravitino production in high scale supersymmetry models where n=6.
We numerically investigate the gravitational waves generated by the head-on collision of equal-mass, self-gravitating, real scalar field solitons (oscillatons) as a function of their compactness C. ...We start with solitons that are initially at rest with respect to each other and show that there exist three different possible outcomes resulting from their collisions: (1) an excited stable oscillaton for low C, (2) a merger and formation of a black hole for intermediate C, and (3) a premerger collapse of both oscillatons into individual black holes for large C. For (1), the excited, aspherical oscillaton continues to emit gravitational waves. For (2), the total energy in gravitational waves emitted increases with compactness and possesses a maximum which is greater than that from the merger of a pair of equivalent mass black holes. The initial amplitudes of the quasinormal modes in the postmerger ringdown in this case are larger than that of collisions of corresponding mass black holes-potentially a key observable to distinguish black-hole mergers from their scalar mimics. For (3), the gravitational wave output is indistinguishable from a similar mass, black hole–black hole merger. Based on our results, LIGO may be sensitive to oscillaton collisions from light scalars of mass 10−12 eV≲m≲10−10 eV.
A
bstract
The observation of coherent elastic neutrino nucleus scattering has opened the window to many physics opportunities. This process has been measured by the COHERENT Collaboration using two ...different targets, first CsI and then argon. Recently, the COHERENT Collaboration has updated the CsI data analysis with a higher statistics and an improved understanding of systematics. Here we perform a detailed statistical analysis of the full CsI data and combine it with the previous argon result. We discuss a vast array of implications, from tests of the Standard Model to new physics probes. In our analyses we take into account experimental uncertainties associated to the efficiency as well as the timing distribution of neutrino fluxes, making our results rather robust. In particular, we update previous measurements of the weak mixing angle and the neutron root mean square charge radius for CsI and argon. We also update the constraints on new physics scenarios including neutrino nonstandard interactions and the most general case of neutrino generalized interactions, as well as the possibility of light mediators. Finally, constraints on neutrino electromagnetic properties are also examined, including the conversion to sterile neutrino states. In many cases, the inclusion of the recent CsI data leads to a dramatic improvement of bounds.
A
bstract
The CENNS-10 experiment of the COHERENT collaboration has recently reported the first detection of coherent-elastic neutrino-nucleus scattering (CEvNS) in liquid Argon with more than 3
σ
...significance. In this work, we exploit the new data in order to probe various interesting parameters which are of key importance to CEvNS within and beyond the Standard Model. A dedicated statistical analysis of these data shows that the current constraints are significantly improved in most cases. We derive a first measurement of the neutron rms charge radius of Argon, and also an improved determination of the weak mixing angle in the low energy regime. We also update the constraints on neutrino non-standard interactions, electromagnetic properties and light mediators with respect to those derived from the first COHERENT-CsI data.
Environmental nontuberculous mycobacteria (NTM) are ubiquitous organisms with which humans commonly interact. The epidemiologic characteristics of NTM diseases including mortality rate and its ...associated factors remain largely unknown. In this study, we explored the geographical area of exposure and mortality and comorbid conditions of affected persons to determine environment, host, and host-pathogen interactive factors.
We analyzed mortality related to nontuberculous mycobacterial infections from 1999 through 2010 by examining multiple-cause-of-death data from the National Center for Health Statistics. Among those who died with these diseases, we analyzed age-adjusted mortality rates, trends, associations with demographic variables, and comorbid conditions and correlated this information with similar data for tuberculosis-related mortality during the same time.
From 1999 through 2010, nontuberculous mycobacterial disease was reported as an immediate cause of death in 2,990 people in the United States with a combined overall mean age-adjusted mortality rate of 0.1 per 100,000 person-years. A significant increase in the number of NTM related deaths was seen from 1999 through 2010 (R(2) = 0.72, p<0.0001), but it was not significant after adjustment for age. Persons aged 55 years and older, women, those living in Hawaii and Louisiana, and those of non-Hispanic, white ethnicity had higher mortality rates. Compared to tuberculosis-related mortality, chronic obstructive pulmonary disease, bronchiectasis, HIV, interstitial lung diseases, and tobacco use were significantly more common in persons with nontuberculous mycobacteria-related deaths.
Nontuberculous mycobacteria-related death numbers are rising and are unevenly distributed. The strong association of nontuberculous mycobacterial disease with age suggests that its prevalence will increase as the United States population ages.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
This work reports on the selective on-line identification of polycyclic aromatic hydrocarbons (PAHs) formed in a low-pressure methane sooting flame, carried out using the double imaging Photoelectron ...Photoion Coincidence Spectroscopy method (i
2
PEPICO) on the DESIRS VUV beamline at the synchrotron SOLEIL. Generally, this work demonstrates the capabilities of the i
2
PEPICO method to identify PAHs in sooting flames, and in particular to distinguish cyclopentaring-fused PAHs (CP-PAHs) and side-substituted PAHs from their benzenoid isomers. Experimental threshold photoelectron spectra of four CP-PAHs: acenapthylene (C
12
H
8
, 152
m
/
z
), acenaphtene (C
12
H
10
, 154
m
/
z
), fluoranthene (C
16
H
10
, 202
m
/
z
) and benzo(
ghi
)fluoranthene (C
18
H
10
, 226
m
/
z
) are also reported for the first time.
Selective on-line identification of polycyclic aromatic hydrocarbons (PAHs) formed in a low-pressure methane sooting flame, carried out using the double imaging Photoelectron Photoion Coincidence Spectroscopy method (i
2
PEPICO).
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