Bonn-Cologne Graduate School of Physics and Astronomy

To better constrain the physical mechanisms driving star formation, we present the first systematic study of the radio continuum size evolution of star-forming galaxies (SFGs) over the redshift range 0.35 < z < 2.25. We use the VLA COSMOS 3 GHz map (noise rms = 2.3 μ Jy beam −1 , θ beam = 0.75 arcsec) to construct a mass-complete sample of 3184 radio-selected SFGs that reside on and above the main sequence (MS) of SFGs. We constrain the overall extent of star formation activity in galaxies by applying a 2D Gaussian model to their radio continuum emission. Extensive Monte Carlo simulations are used to validate the robustness of our measurements and characterize the selection function. We find no clear dependence between the radio size and stellar mass, M ⋆ , of SFGs with 10.5 ≲ log( M ⋆ / M ⊙ ) ≲ 11.5. Our analysis suggests that MS galaxies are preferentially extended, while SFGs above the MS are always compact. The median effective radius of SFGs on (above) the MS of R eff = 1.5 ± 0.2 (1.0 ± 0.2) kpc remains nearly constant with cosmic time; a parametrization of the form R eff ∝ (1 + z ) α yields a shallow slope of only α = −0.26 ± 0.08 (0.12 ± 0.14) for SFGs on (above) the MS. The size of the stellar component of galaxies is larger than the extent of the radio continuum emission by a factor ∼2 (1.3) at z = 0.5 (2), indicating star formation is enhanced at small radii. The galactic-averaged star formation rate surface density (Σ SFR ) scales with the distance to the MS, except for a fraction of MS galaxies (≲10%) that harbor starburst-like Σ SFR . These “hidden” starbursts might have experienced a compaction phase due to disk instability and/or a merger-driven burst of star formation, which may or may not significantly offset a galaxy from the MS. We thus propose to use Σ SFR and distance to the MS in conjunction to better identify the galaxy population undergoing a starbursting phase.

The COVID-19 pandemic has triggered unprecedented societal disruption and disproportionately affected global mobility dynamics. Within such a troubled and intensifying crisis, the intersection of migration and gender is even more unsettling. Since the pandemic outbreak, Bangladesh witnessed a colossal crisis among millions of Bangladeshi migrants working overseas-a considerable section of them are women. By highlighting the plight of the Bangladeshi women migrants in the Gulf Cooperation Council (GCC) countries, this study expands the emerging literature that addresses the nexus among migration, pandemic fallout and gendered labour. Redrawing our understanding of globalization from below, the study attempts to further advance the theoretical perspectives on the predicaments of globalization and gendered precarity in contract labour migration. The study argues that the focus on the power asymmetry between the host and sending countries remains too limited to provide a comprehensive understanding of how inequalities are reproduced and transformed. Instead, it suggests that the challenges and disadvantages women migrants endure are embedded in the asymmetries of deep-rooted economic and social structures in tandem with the systemic practice of otherness and exclusion.

Two new prenylflavonol glycosides epimedokoreanoside I ( 7) and epimedokoreanoside II ( 8) were isolated from EPIMEDIUM KOREANUM Nakai (Berberidaceae) beside five other known prenylflavonol glycosides with hypotensive activity. The structures were elucidated by spectroscopic and chemical methods.

We investigate the linear radio size properties of the μ Jy populations of radio-selected active galactic nuclei (AGN) and star-forming galaxies (SFGs) using a multi-resolution catalog based on the original VLA-COSMOS 3 GHz 0.″75 resolution mosaic and its convolved images (up to a resolution of 2.″2). The final catalog contains 6399 radio sources above a 3 GHz total flux density of S T > 20 μ Jy (median ⟨ S T ⟩=37 μ Jy), with redshift information (median ⟨ z ⟩=1.0), and multi-wavelength classification as SFGs, radio-excess AGN (RX-AGN), or non-radio-excess AGN (NRX-AGN). RX-AGN are those whose radio emission exceeds the star formation rate derived by fitting the global spectral energy distribution. We derive the evolution with redshift and luminosity of the median linear sizes of each class of objects. We find that RX-AGN are compact, with median sizes of ∼1–2 kpc and increasing with redshift, corresponding to an almost constant angular size of 0.″25. NRX-AGN typically have radio sizes a factor of 2 larger than the RX-AGN. The median radio size of SFGs is about 5 kpc up to z ∼ 0.7, and it decreases beyond this redshift. Using luminosity-complete subsamples of objects, we separately investigate the effect of redshift and luminosity dependance. We compare the radio sizes of SFGs with those derived in the rest-frame far-infrared (FIR) and UV bands. We find that SFGs have comparable sizes (within 15%) in the radio and rest-frame FIR, while the sizes measured in the UV-band are systematically larger than the radio sizes.

The heavily cross-linked microtubule (MT) bundles found in neuronal processes play a central role in the initiation, growth and maturation of axons and dendrites; however, a quantitative understanding of their mechanical function is still lacking. We here developed computer simulations to investigate the dynamics of force generation in 1D bundles of MTs that are cross-linked and powered by molecular motors. The motion of filaments and the forces they exert are investigated as a function of the motor type (unipolar or bipolar), MT density and length, applied load, and motor connectivity. We demonstrate that only unipolar motors (e.g., kinesin-1) can provide the driving force for bundle expansion, while bipolar motors (e.g., kinesin-5) oppose it. The force generation capacity of the bundles is shown to depend sharply on the fraction of unipolar motors due to a percolation transition that must occur in the bundle. Scaling laws between bundle length, force, MT length and motor fraction are presented. In addition, we investigate the dynamics of growth in the presence of a constant influx of MTs. Beyond a short equilibration period, the bundles grow linearly in time. In this growth regime, the bundle extends as one mass forward with most filaments sliding with the growth velocity. The growth velocity is shown to be dictated by the inward flux of MTs, to inversely scale with the load and to be independent of the free velocity of the motors. These findings provide important molecular-level insights into the mechanical function of the MT cytoskeleton in normal axon growth and regeneration after injury.

Summary: Background: This single center prospective randomized study was performed to compare the effect of endovenous laser flush ablation (EVLAf) of the great saphenous vein (GSV) close to the sapheno-femoral junction (SFJ) with a standard ablation (EVLAs) up to two cm distally of the SFJ on reflux in the GSV stump. Patients and methods: Between April 2013 and January 2016, 146 legs in 146 consecutive patients, meeting the inclusion/exclusion criteria, were treated by EVLA. All patients were randomized into 2 groups. In group 1 EVLAf started from the SFJ level, and in group 2 EVLAs started two cm below the SFJ. The primary endpoint was reflux in the GSV stump after 900 days. Secondary endpoints were reflux in the anterior accessory saphenous vein (AASV), proximal clinically recurrent varicose veins related to reflux in the stump and/or the AASV. Results: At day 900, 27 patients were lost to follow-up. Reflux in the stump was detected in 3.6% in group 1 and in 22.2% in group 2 (p<0.05). Reflux in the AASV was present in 7.1% in group 1 and in 17.46% in group 2 (p=0.09). Proximal clinically recurrent varicose veins were observed in 8.9% in group 1 and in 19.1% in group 2 (p=0.12). The greatest diameter of the stump was significantly larger in group 2 (group 1: 0.41 cm, group 2: 0.6 cm, p<0.001). Conclusions: EVLAf is associated with a significantly lower incidence of reflux in the GSV stump, with a trend to a lower incidence of reflux in the AASV and with a lower incidence of proximal recurrent varicose veins after 900 days follow-up compared to EVLAs. EVLAf may improve the clinical recurrence rate after EVLA of the GSV.

This paper reports findings from interview surveys with 1215 respondents, split between the capital cities (Yerevan, Baku and Tbilisi) and one non-capital region (Kotayk, Aran-Mugan and Shida Kartli) in each of the three South Caucasus countries - Armenia, Azerbaijan and Georgia. The respondents, who were drawn from households in larger representative household social surveys, were all born between 1970 and 1976 and were aged 31-37 at the time of the fieldwork in 2007. Their life stage transitions from childhood to adulthood had roughly coincided with their countries' transitions from communism to post-communism. Data was collected on the samples' participation in selected leisure activities from age 16 to 30. Similar data was collected on the samples' careers in education, the labour market, housing and family relationships. This information enables us to identify typical leisure careers and how their development was affected by events in other life domains, all in the context of the macro-changes that were in process in each of the research locations. The evidence enables both personal leisure careers and aggregate leisure trends in different socio-demographic groups to be identified This shows that changes in leisure behaviour between age 16 and 30 were neither widening nor narrowing the differences between the leisure of males and females, or those who married and became parents on the one hand, then, on the other, those who were still single and childless at age 30. In contrast, differences by place, and by social class, grew progressively wider, thus raising the social costs of geographical and social mobility. Changes in leisure behaviour between age 16 and 30 were separating young adults into those who participated in little, if any, structured out-of-home leisure, whose main leisure spending, if any, was on alcohol and tobacco (typically consumed in homes and neighbourhoods), and those whose leisure was characterised by relatively high and sustained participation in sport, consumption of high culture, and going out to bars, cafes, cinema, discos, etc.

Abstract The ESO/MPG WFI and the INT WFC wide field archives comprising 330 000 images were mined to search for serendip‐itous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 152 as‐teroids (44 PHAs and 108 other NEAs) were identified using the PRECOVERY software, their astrometry being measured on 761 images and sent to the Minor Planet Centre. Both recoveries and precoveries were reported, including prolonged orbital arcs for 18 precovered objects and 10 recoveries. We analyze all new opposition data by comparing the orbits fitted before and after including our contributions. We conclude the paper presenting “Mega‐Precovery”, a new online service focused on data mining of many instrument archives simultaneously for one or a few given asteroids. A total of 28 instrument archives have been made available for mining using this tool, adding together about 2.5 million images forming the “Mega‐Archive”

We studied the molecular gas properties of AzTEC/C159, a star-forming disk galaxy at z = 4.567, in order to better constrain the nature of the high-redshift end of the submillimeter-selected galaxy (SMG) population. We secured 12 CO molecular line detections for the J = 2 →1 and J = 5 →4 transitions using the Karl G. Jansky Very Large Array (VLA) and the NOrthern Extended Millimeter Array (NOEMA) interferometer. The broad ( FWHM ~ 750 km s −1 ) and tentative double-peaked profiles of the two 12 CO lines are consistent with an extended molecular gas reservoir, which is distributed in a rotating disk, as previously revealed from [CII] 158 μ m line observations. Based on the 12 CO(2 →1) emission line, we derived L ′ CO =(3.4±0.6)×10 10 K km s −1 pc 2 , which yields a molecular gas mass of M H 2 (α CO /4.3)=(1.5±0.3)×10 11 M ⊙ and unveils a gas-rich system with μ gas (α CO /4.3)≡ M H 2 /M ⋆ =3.3±0.7. The extreme star formation efficiency of AzTEC/C159, parametrized by the ratio L IR / L ′ CO =(216±80) L ⊙ (K km s −1 pc 2 ) −1 , is comparable to merger-driven starbursts such as local ultra-luminous infrared galaxies and SMGs. Likewise, the 12 CO(5 →4)/CO(2 →1) line brightness temperature ratio of r 52 = 0.55 ± 0.15 is consistent with high-excitation conditions as observed in SMGs. Based on mass budget considerations, we constrained the value for the L ′ CO – H 2 mass conversion factor in AzTEC/C159, that is, α CO =3.9 −1.3 +2.7 M ⊙ K −1 km −1 s pc −2 , which is consistent with a self-gravitating molecular gas distribution as observed in local star-forming disk galaxies. Cold gas streams from cosmological filaments might be fueling a gravitationally unstable gas-rich disk in AzTEC/C159, which breaks into giant clumps and forms stars as efficiently as in merger-driven systems and generates high gas excitation. These results support the evolutionary connection between AzTEC/C159-like systems and massive quiescent disk galaxies at z ~ 2.

Context. The discovery of the M − σ relation, the local galaxy bimodality, and the link between black-hole and host-galaxy properties have raised the question of whether active galactic nuclei (AGN) play a role in galaxy evolution. AGN feedback is one of the biggest observational challenges of modern extragalactic astrophysics. Several theoretical models implement AGN feedback to explain the observed galaxy luminosity function and, possibly, the color and morphological transformation of spiral galaxies into passive ellipticals.

PURPOSE: The aim of this project was to develop a GRAPPA-based reconstruction for wave-CAIPI data. Wave-CAIPI fully exploits the 3D coil sensitivity variations by combining corkscrew k-space trajectories with CAIPIRINHA sampling. It reduces artifacts and limits reconstruction induced spatially varying noise enhancement. The GRAPPA-based wave-CAIPI method is robust and does not depend on the accuracy of coil sensitivity estimations. METHODS: We developed a GRAPPA-based, noniterative wave-CAIPI reconstruction algorithm utilizing multiple GRAPPA kernels. For data acquisition, we implemented a fast 3D magnetization-prepared rapid gradient-echo wave-CAIPI sequence tailored for ultra-high field application. The imaging results were evaluated by comparing the g-factor and the root mean square error to Cartesian CAIPIRINHA acquisitions. Additionally, to assess the performance of subcortical segmentations (calculated by FreeSurfer), the data were analyzed across five subjects. RESULTS: Sixteen-fold accelerated whole brain magnetization-prepared rapid gradient-echo data (1 mm isotropic resolution) were acquired in 40 seconds at 7T. A clear improvement in image quality compared to Cartesian CAIPIRINHA sampling was observed. For the chosen imaging protocol, the results of 16-fold accelerated wave-CAIPI acquisitions were comparable to results of 12-fold accelerated Cartesian CAIPIRINHA. In comparison to the originally proposed SENSitivity Encoding reconstruction of Wave-CAIPI data, the GRAPPA approach provided similar image quality. CONCLUSION: High-quality, wave-CAIPI magnetization-prepared rapid gradient-echo images can be reconstructed by means of a GRAPPA-based reconstruction algorithm. Even for high acceleration factors, the noniterative reconstruction is robust and does not require coil sensitivity estimations. By altering the aliasing pattern, ultra-fast whole-brain structural imaging becomes feasible.

Sound encoding is mediated by Ca(2+) influx-evoked release of glutamate at the ribbon synapse of inner hair cells. Here we studied the role of ATP in this process focusing on Ca(2+) current through CaV1.3 channels and Ca(2+) homeostasis in mouse inner hair cells. Patch-clamp recordings and Ca(2+) imaging demonstrate that hydrolyzable ATP is essential to maintain synaptic Ca(2+) influx in inner hair cells via fueling Ca(2+)-ATPases to avoid an increase in cytosolic [Ca(2+)] and subsequent Ca(2+)/calmodulin-dependent inactivation of CaV1.3 channels.

Time constraints placed on magnetic resonance imaging often restrict the application of advanced diffusion MRI (dMRI) protocols in clinical practice and in high throughput research studies. Therefore, acquisition strategies for accelerated dMRI have been investigated to allow for the collection of versatile and high quality imaging data, even if stringent scan time limits are imposed. Diffusion spectrum imaging (DSI), an advanced acquisition strategy that allows for a high resolution of intra-voxel microstructure, can be sufficiently accelerated by means of compressed sensing (CS) theory. CS theory describes a framework for the efficient collection of fewer samples of a data set than conventionally required followed by robust reconstruction to recover the full data set from sparse measurements. For an accurate recovery of DSI data, a suitable acquisition scheme for sparse q-space sampling and the sensing and sparsifying bases for CS reconstruction need to be selected. In this work we explore three different types of q-space undersampling schemes and two frameworks for CS reconstruction based on either Fourier or SHORE basis functions. After CS recovery, diffusion and microstructural parameters and orientational information are estimated from the reconstructed data by means of state-of-the-art processing techniques for dMRI analysis. By means of simulation, diffusion phantom and in vivo DSI data, an isotropic distribution of q-space samples was found to be optimal for sparse DSI. The CS reconstruction results indicate superior performance of Fourier-based CS-DSI compared to the SHORE-based approach. Based on these findings we outline an experimental design for accelerated DSI and robust CS reconstruction of the sparse measurements that is suitable for the application within time-limited studies.

Abstract Purpose Numerous endeavors have been undertaken to preserve hearing in cochlear implant (CI) patients. Particularly, optimization of electrode array design aims at preservation of residual hearing (RH). This study examines whether a slim perimodiolar (PM) electrode array could bear the capability to preserve hearing. Methods A total of 47 patients underwent cochlear implantation receiving the PM electrode. (i) Patients with pure tone audiogram (PTA) thresholds better than 85 dB and/or hearing loss for Freiburg speech test numbers less than 60 dB and more than 50% maximum monosyllabic understanding were assigned to the RH group ( n = 17), while all others belonged to the noRH group ( n = 30). (ii) Another group implanted with a slim straight, lateral wall (LW) electrode was recruited for comparison. Results We compared 17 RH–30 noRH patients all receiving the PM electrode. RH in PM recipients decreased faster than in LW recipients. No significant differences were observed between both (RH v/s noRH) groups in NRT thresholds, Freiburg speech test and A§E ® phonemes. Analogous satisfaction levels were indicated through the questionnaires in terms of sound quality, hearing in silence, noise and directional hearing in both groups. Conclusions The results suggest that hearing preservation is influenced not only by electrode shape but various factors. This study opens an avenue for further investigations to elucidate and enumerate the causes for progressive hearing loss.

Abstract The Canada‐France‐Hawaii Legacy Survey (CFHTLS) comprising about 25 000 MegaCam images was data mined to search for serendipitous encounters of known Near Earth Asteroids (NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 143 asteroids (109 NEAs and 34 PHAs) were found on 508 candidate images which were field corrected and measured carefully, and their astrometry was reported to Minor Planet Centre. Both recoveries and precoveries (apparitions before discovery) were reported, including data for 27 precovered asteroids (20 NEAs and 7 PHAs) and 116 recovered asteroids (89 NEAs and 27 PHAs). Our data prolonged arcs for 41 orbits at first or last opposition, refined 35 orbits by fitting data taken at one new opposition, recovered 6 NEAs at their second opposition and allowed us to ameliorate most orbits and their Minimal Orbital Intersection Distance (MOID), an important parameter to monitor for potential Earth impact hazard in the future (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

As part of the EURONEAR project, almost 70,000 mosaic Suprime‐Cam images taken between 1999 and 2013 were data‐mined for about 9,800 near‐Earth asteroids (NEAs) known by 2013 May. Using our PRECOVERY server and the new Find Subaru CCD tool, we scrutinized 4,186 candidate CCD images possibly holding 518 NEAs. We found 113 NEAs as faint as V <25 magnitude, their positions being measured in 589 images using Astrometrica, and then reported to the Minor Planet Center. Among them, 18 objects represent encounters of previously single opposition NEAs, their orbital arcs being extended by up to 10 years. In the second part of this work, we searched for unknown NEAs in 78 sequences (780 CCD fields) of 4–5 mosaic images selected from the same Suprime‐Cam archive and totaling 16.6 deg 2 , with the aim to assess the faint NEA distribution observable with an 8‐m class survey. A total of 2,018 moving objects were measured, from which we identified 18 better NEA candidates. Using the R c filter in good weather conditions, mostly dark time and sky directions slightly biased towards the ecliptic, at least one NEA could be discovered in every 1 deg 2 surveyed.

The paper examines the impact of improving the characteristics of the national investment climate rating of a subject of the Russian Federation on economic development. Based on the analysis of regional panel data for the period from 2014 to 2018, it was shown that an increase in the rating of a region is associated with an inflow of investments and an increase in GRP. One of the identified channels of this influence is associated with the market of highly skilled labor. It is demonstrated that, given the inaccessibility of detailed information about the results of the regions development to investors, the rating does not fully function as a signal to them. Based on the obtained results, the recommendations for improving the rating methodology were formulated.

We studied the molecular gas properties of AzTEC/C159, a star-forming disk galaxy at z = 4.567, in order to better constrain the nature of the high-redshift end of the sub-mm selected galaxy (SMG) population. We secured ^12CO molecular line detections for the J=2→1 and J=5→4 transitions using the Karl G. Jansky Very Large Array (VLA) and the NOrthern Extended Millimeter Array (NOEMA) interferometer. The broad (FWHM∼ 750 km s−1 ) and tentative double-peaked profiles of both ^12CO lines are consistent with an extended molecular gas reservoir, which is distributed in a rotating disk as previously revealed from [CII] 158 µm line observations. Based on the ^12CO(2→1) emission line we derived L’CO = (3.4 ± 0.6) × 10^10 K km s^⁻1pc^2, that yields a molecular gas mass of MH2 (αCO/4.3) = (1.5 ± 0.3) × 10^11 M and unveils a gas-rich system with µgas(αCO/4.3) ≡ MH₂ /M∗ = 3.3 ± 0.7. The extreme star formation efficiency (SFE) of AzTEC/C159, parametrized by the ratio L_IR/L’_CO = (216 ± 80) L⊙ (K km s^⁻1pc^2) ⁻1, is comparable to merger-driven starbursts such as local ultra-luminous infrared galaxies (ULIRGs) and SMGs. Likewise, the ^12CO(5→4)/CO(2→1) line brightness temperature ratio of r_52 = 0.55 ± 0.15 is consistent with high excitation conditions, similar to that observed in SMGs. Based on mass budget considerations we constrained the value for the L 0 CO – H2 mass conversion factor in AzTEC/C159, i.e. αCO = 3.9 ^+2.7 _−1.3 M⊙K^ ⁻1 km s^⁻1pc^2, that is consistent with a self-gravitating molecular gas distribution as observed in local star-forming disk galaxies. Cold gas streams from cosmological filaments might be fueling a gravitationally unstable gas-rich disk in AzTEC/C159, which breaks into giant clumps forming stars as efficiently as in merger-driven systems and generate high gas excitation. These results support the evolutionary connection between AzTEC/C159-like systems and massive quiescent disk galaxies at z ∼ 2.

The Indian bureaucracy suffers from indecision and risk aversion, resulting in an inordinate focus on routine tasks, coordination failures, process overload, poor perception, motivational issues, and a deterioration in the quality of service delivery. We argue that bureaucratic indecision, in large part, is a form of rational self- preservation exercised by bureaucrats from the various legal and extra-legal risks to their person, careers and reputation. These risks originate from problems of organizational design, institutional norms, and other political factors. The research for this paper included a review of interdisciplinary literature on bureaucracy and policy decisions, combined with semi-structured interviews. We interviewed current and ex-bureaucrats from India and other Asian and African countries, political scientists, and other policy researchers. We also conducted a document analysis of historical and contemporary, administrative, and legal documents, including committee reports, acts and rules, annual reports, and other government publications. We summarise the evidence on factors such as penal transfers, overload, inadequate training, process accountability, contradictory rules, and political patronage.