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Context. The extended ultraviolet (XUV) disks of nearby galaxies show ongoing massive-star formation, but their parental molecular clouds remain mostly undetected despite searches in CO(1–0) and CO(2–1). The recent detection of 23 clouds in the higher excitation transition CO(3–2) within the XUV disk of M83 thus requires an explanation. Aims. We test the hypothesis introduced to explain the non-detections and recent detection simultaneously: The clouds in XUV disks have a clump-envelope structure similar to those in Galactic star-forming clouds, having dense star-forming clumps (or concentrations of multiple clumps) at their centers, which predominantly contribute to the CO(3–2) emission and are surrounded by less dense envelopes, where CO molecules are photo-dissociated due to the low-metallicity environment there. Methods. We utilize new high-resolution ALMA CO(3–2) observations of a subset (11) of the 23 clouds in the XUV disk of M83. Results. We confirm the compactness of the CO(3–2)-emitting dense clumps (or their concentrations), finding clump diameters below the spatial resolution of 6–9 pc. This is similar to the size of the dense gas region in the Orion A molecular cloud, a local star-forming cloud with massive-star formation. Conclusions. The dense star-forming clumps are common between normal and XUV disks. This may also indicate that once the cloud structure is set, the process of star formation is governed by the cloud's internal physics rather than by external triggers. This simple model explains the current observations of clouds with ongoing massive-star formation, although it may require some adjustment, for example including the effect of cloud evolution, to describe star formation in molecular clouds more generally. [ABSTRACT FROM AUTHOR]

This paper focuses on the historical development and dynamics of political and administrative structures in regions of a fragmented empire that cannot be simply described as marginal 'mouseholes'. Rather, it should be acknowledged that these spaces were part and parcel of a wider area (the Byzantine insular and coastal koine) , which encompassed coastal areas as well as insular communities promoting socio-economic contact and cultural interchange. More importantly, they also boasted a peculiar set of material indicators suggesting a certain common cultural unity and identity. The koine coincided with liminal territories and the seas on which the Byzantine Empire retained political and naval rulership. Such liminal territories showed varied – yet coherent– administrative infrastructures and political practices on the part of local elites. [ABSTRACT FROM AUTHOR]

Finding new interventions that slow ageing and maintain human health is a huge challenge of our time. The nematode Caenorhabditis elegans offers a rapid in vivo method to determine whether a compound extends its 2 to 3-week lifespan. Measuring lifespan is the standard method to monitor ageing, but a compound that extends lifespan will not necessarily maintain health. Here, we describe the automated monitoring of C. elegans movement from early to mid-adulthood as a faster healthspan-based method to measure ageing. Using the WormGazer™ technology, multiple Petri dishes each containing several C. elegans worms are imaged simultaneously and non-invasively by an array of cameras that can be scaled easily. This approach demonstrates that most functional decline in C. elegans occurs during the first week of adulthood. We find 7 days of imaging is sufficient to measure the dose-dependent efficacy of sulfamethoxazole to slow ageing, compared to 40 days required for a parallel lifespan experiment. Understanding any negative consequences of interventions that slow ageing is important. We show that the long-lived mutant age-1(hx546) stays active for longer than the wild type but it moves slower in early adulthood. Thus, continuous analysis of movement can rapidly identify interventions that slow ageing while simultaneously revealing any negative effects on health. [ABSTRACT FROM AUTHOR]

Filamentary flows towards the centre of molecular clouds have been recognized as a crucial process in the formation and evolution of stellar clusters. In this paper, we present a comprehensive observational study that investigates the gas properties and kinematics of the Giant Molecular Cloud G148.24+00.41 using the observations of CO (1-0) isotopologues. We find that the cloud is massive (105 M⊙) and is one of the most massive clouds of the outer Galaxy. We identified six likely velocity coherent filaments in the cloud having length, width, and mass in the range of 14–38 pc, 2.5–4.2 pc, and (1.3–6.9) × 103 M⊙, respectively. We find that the filaments are converging towards the central area of the cloud, and the longitudinal accretion flows along the filaments are in the range of ∼ 26–264 M⊙ Myr−1. The cloud has fragmented into seven clumps having mass in the range of ∼ 260–2100 M⊙ and average size around ∼ 1.4 pc, out of which the most massive clump is located at the hub of the filamentary structures, near the geometric centre of the cloud. Three filaments are found to be directly connected to the massive clump and transferring matter at a rate of ∼ 675 M⊙ Myr−1. The clump hosts a near-infrared cluster. Our results show that large-scale filamentary accretion flows towards the central region of the collapsing cloud is an important mechanism for supplying the matter necessary to form the central high-mass clump and subsequent stellar cluster. [ABSTRACT FROM AUTHOR]

The relative importance of magnetic fields, turbulence, and gravity in the early phases of star formation is still not well understood. We report the first high-resolution dust polarization observations at 850  |$\mu$| m around the most massive clump, located at the hub of the Giant Molecular Cloud G148.24+00.41, using SCUBA-2/POL-2 at the James Clerk Maxwell Telescope. We find that the degree of polarization decreases steadily towards the denser portion of the cloud. Comparing the intensity gradients and local gravity with the magnetic field orientations, we find that local gravity plays a dominant role in driving the gas collapse as the magnetic field orientations and gravity vectors seem to point towards the dense clumps. We also find evidence of U-shaped magnetic field morphology towards a small-scale elongated structure associated with the central clump, hinting at converging accretion flows towards the clump. Our observation has resolved the massive clump into multiple substructures. We study the magnetic field properties of two regions, central clump (CC) and northeastern elongated structure (NES). Using the modified Davis–Chandrasekhar–Fermi method, we determine that the magnetic field strengths of CC and NES are ∼24.0 ± 6.0  |$\mu$| G and 20.0 ± 5.0  |$\mu$| G, respectively. The mass-to-flux ratios are found to be magnetically transcritical/supercritical, while the Alfv |$\acute{\text{e}}$| n Mach number indicates a trans-Alfv |$\acute{\text{e}}$| nic state in both regions. These results, along with Virial analysis, suggest that at the hub of G148.24+00.41, gravitational energy has an edge over magnetic and kinetic energies. [ABSTRACT FROM AUTHOR]

Context. The impact of stellar feedback on the Kennicutt–Schmidt (KS) law, which relates the star formation rate (SFR) to the surface gas density, is a topic of ongoing debate. The interpretation of high-resolution observations of individual clouds is challenging due to the various processes at play simultaneously and inherent biases. Therefore, a numerical investigation is necessary to understand the role of stellar feedback and identify observable signatures. Aims. In this study we investigate the impact of stellar feedback on the KS law, aiming to identify distinct signatures that can be observed and analysed. By employing magnetohydrodynamic simulations of an isolated cloud, we specifically isolate the effects of high-mass star radiation feedback and protostellar jets. High-resolution numerical simulations are a valuable tool for isolating the impact of stellar feedback on the star formation process, while also allowing us to assess how observational biases may affect the derived relation. Methods. We used high-resolution (<0.01 pc) magnetohydrodynamic numerical simulations of a 104M⊙ cloud and followed its evolution under different feedback prescriptions. The set of simulations contained four types of feedback: one with only protostellar jets, one with ionising radiation from massive stars (>8 M⊙), one with the combination of the two, and one without any stellar feedback. In order to compare these simulations with the existing observational results, we analysed their evolution by adopting the same techniques applied in the observational studies. Then, we simulated how the same analyses would change if the data were affected by typical observational biases: counting young stellar objects (YSO) to estimate the SFR, the limited resolution for the column density maps, and a sensitivity threshold for detecting faint embedded YSOs. Results. Our analysis reveals that the presence of stellar feedback strongly influences the shape of the KS relation and the star formation efficiency per free-fall time (ϵff). The impact of feedback on the relation is primarily governed by its influence on the cloud's structure. Additionally, the evolution of ϵff throughout the star formation event suggests that variations in this quantity can mask the impact of feedback in observational studies that do not account for the evolutionary stage of the clouds. Although the ϵff measured in our clouds is higher than what is usually observed in real clouds, upon applying prescriptions to mimic observational biases we recover a good agreement with the expected values. From that, we can infer that observations tend to underestimate the total SFR. Moreover, this likely indicates that the physics included in our simulations is sufficient to reproduce the basic mechanisms that contribute to setting ϵff. Conclusions. We demonstrate the interest of employing numerical simulations to address the impact of early feedback on star formation laws and to correctly interpret observational data. This study will be extended to other types of molecular clouds and ionising stars, sampling different feedback strengths, to fully characterise the impact of H II regions on star formation. [ABSTRACT FROM AUTHOR]

Illusions are important 'tools' in the study of perceptual processes. Their conception is typically linked to the notion of veridicality in a dual-world framework, in which we either see the macro physical world as it is (ecological approaches) or we derive a faithful representation (cognitive approaches) of it. Within such theoretical views, illusions are errors caused by inadequate sensory information (because of poor quality, insufficient quantity, contradictory, etc.). From a phenomenological stance, however, experiencing an illusion does not relate to the physical quality of the distal or proximal stimulus; rather, it depends on a comparison between the actual perception and what one believes should be perceived given the knowledge s/he has gained about the physical stimulus. Within such a framework, illusions are still considered of extreme importance in the study of the processes underpinning perception, but they are not conceived as errors. They represent instead a cognitive clash between actual perception and hypothesized perception based on some sort of comparison, thus also showing their potential as a tool for studying the underpinnings of cognitive processes. [ABSTRACT FROM AUTHOR]

Copyright of Italian Journal of Groundwater / Acque Sotterranee is the property of PAGEPress and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Clouds more massive than about 105 M⊙ are potential sites of massive cluster formation. Studying the properties of such clouds in the early stages of their evolution offers an opportunity to test various cluster formation processes. We make use of CO, Herschel , and UKIDSS observations to study one such cloud, G148.24+00.41. Our results show the cloud to be of high mass (⁠|$\sim \, 1.1\times 10^5$| M⊙), low dust temperature (∼ 14.5 K), nearly circular (projected radius ∼ 26 pc), and gravitationally bound with a dense gas fraction of ∼18 per cent and a density profile with a power-law index of ∼−1.5. Comparing its properties with those of nearby molecular clouds, we find that G148.24+00.41 is comparable to the Orion-A molecular cloud in terms of mass, size, and dense gas fraction. From our analyses, we find that the central area of the cloud is actively forming protostars and is moderately fractal with a Q -value of ∼ 0.66. We also find evidence of global mass-segregation with a degree of mass-segregation (ΛMSR) ≈ 3.2. We discuss these results along with the structure and compactness of the cloud, the spatial and temporal distribution of embedded stellar population and their correlation with the cold dust distribution, in the context of high-mass cluster formation. We compare our results with models of star cluster formation, and conclude that the cloud has the potential to form a cluster in the mass range ∼ 2000–3000 M⊙ through dynamical hierarchical collapse and assembly of both gas and stars. [ABSTRACT FROM AUTHOR]

Whether ionization feedback triggers the formation of massive stars is highly debated. Using ALMA 3-mm observations with a spatial resolution of ∼0.05 pc and a mass sensitivity of 1.1  |$\rm M_\odot$|  per beam at 20 K, we investigate the star formation and gas flow structures within the ionizing feedback-driven structure, a clump-scale massive (≳ 1500  |$\rm M_\odot$|⁠) bright-rimmed cloud (BRC) associated with IRAS 18290–0924. This BRC is bound only if external compression from ionized gas is considered. A small-scale (≲ 1 pc) age sequence along the direction of ionizing radiation is revealed for the embedded cores and protostars, which suggests triggered star formation via radiation-driven implosion (RDI). Furthermore, filamentary gas structures converge towards the cores located in the BRC's centre, indicating that these filaments are fueling mass towards cores. The local core-scale mass infall rate derived from H13CO+  J  = 1 − 0 blue profile is of the same order of magnitude as the filamentary mass inflow rate, approximately 1  |$\rm M_\odot$|  kyr−1. A photodissociation region (PDR) covering the irradiated clump surface is detected in several molecules, such as CCH, HCO+, and CS whereas the spatial distribution stratification of these molecules is indistinct. CCH spectra of the PDR possibly indicate a photoevaporation flow leaving the clump surface with a projected velocity of ∼2 km s−1. Our new observations show that RDI accompanied by a clump-fed process is operating in this massive BRC. Whether this combined process works in other massive BRCs is worth exploring with dedicated surveys. [ABSTRACT FROM AUTHOR]

The aim of the paper is to reassess urban trajectories in the Mediterranean during the passage from Late Antiquity to the early Middle Ages. This will be done by focusing on the sites of Amorium, Gortyn, Eleutherna, and Comacchio, places which transcend both the terrestrial and maritime, and the political and military frontiers of the Byzantine empire and the Umayyad Caliphate. Archaeology and material culture will be used - in a comparative perspective - to dissect urban bodies in terms of use of space and function of spatial relationship. This is in order to document the construction of urban models, structures, and infrastructures, which, although often stemming from diverse centralized political and administrative policies, nevertheless accommodated common, cross-cultural developments, including the creation of commercial and artisanal facilities, construction or restoration of religious buildings as foci of settlement, and resilience of local elites as a catalyst of patronage and levels of demand. Particular attention will be given to the role of public spaces as the frame of reference. Indeed, such spaces will be used to show how artistic and architectural displays operated, cultural assumptions could be (re-) discussed, and different types of buildings coexisted. In this respect, the paper will also explore the continuous importance of civic infrastructures and religious buildings as pillars of a yet coherent urban fabric, representatives of the power and wealth of local city-oriented elites, and conveyors of political, artistic, and spatial symbolism, as mutually recognized and experienced by the communities frequenting seventh-to-ninth century eastern Mediterranean urban spaces. [ABSTRACT FROM AUTHOR]

We report an effect of anomalous transparency that is similar to other phantom effects. In an experiment aimed at testing the combined role of (i) motion of the occluding surface and (ii) lightness contrast and polarity on the perception of anomalous transparency, we found that transparency is perceived only with low contrast, and enhanced when the occluding surface is moving. A tentative explanation is suggested, based on simultaneous lightness contrast as a segregation factor and on motion as an integration factor, and discussed in light of previous studies conducted in the theoretical framework of Gestalt theories in perception. [ABSTRACT FROM AUTHOR]

We present results from two experiments aimed at studying the direction of Mona Lisa's gaze and its affective expression. In experiment 1 we studied the effect of retinal image size on the perception of her gaze by manipulating observation distances of a high-quality print of the painting. Participants (N = 30) were asked to answer a simple question (is the person portrayed looking at you) from six different distances ranging from 55 to 755 cm. One group of participants started evaluations from 55 cm; the other group did the opposite. Results show an effect of distance on the perception of Mona Lisa's gaze as staring at the observer: from the furthest distances, the impression of a staring Mona Lisa is robust; from the nearest distances, such impression becomes ambiguous. Experiment 2 presents data concerning the direction of Mona Lisa's gaze and whether this appears to be smiling, derived from an experiment aimed at studying the impression of gaze (direction and emotional content) in portraits (paintings and photographs). Only data concerning Mona Lisa are reported. Participants (N = 41) were randomly assigned to one of two groups: on a LCD screen, one group saw the entire head, and the other group saw only a section reproducing Mona Lisa's eyes. Experimental sessions were two: in session 1 participants had to decide whether the image (whole-head or eyes only) was looking at them; in session 2 participants had to decide whether the head (or the eyes) was smiling. RTs from the two groups of participants were not statistically significant. Results for session 1 confirm experiment 1's general findings. Results for session 2 clearly show that Mona Lisa is not only smiling with her face, but also with her eyes. Results are discussed in relation to the literature on Mona Lisa's gaze and smile. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mediterranean Knowledge is the property of International Centre for Studies & Research (ICSR) Mediterranean Knowledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We present a comprehensive multiwavelength investigation of a likely massive young cluster “IRAS 05100+3723” and its environment with the aim to understand its formation history and feedback effects. We find that IRAS 05100+3723 is a distant (∼3.2 kpc), moderate-mass (∼500 M ⊙), young (∼3 Myr) cluster with its most massive star being an O8.5V type. From spectral modeling, we estimate the effective temperature and log g of the star to be ∼33,000 K and ∼3.8, respectively. Our radio continuum observations reveal that the star has ionized its environment, forming a H ii region of size ∼2.7 pc, temperature ∼5700 K, and electron density ∼165 cmâˆ'3. However, our large-scale dust maps reveal that it has heated the dust up to several parsecs (∼10 pc) in the range 17âˆ'28 K and the morphology of warm dust emission resembles a bipolar H ii region. From dust and 13CO gas analyses, we find evidence that the formation of the H ii region has occurred at the very end of a long filamentary cloud around 3 Myr ago, likely due to edge collapse of the filament. We show that the H ii region is currently compressing a clump of mass ∼2700 M ⊙ at its western outskirts, at the junction of the H ii region and filament. We observe several 70 ÎĽ m point sources of intermediate mass and class 0 nature within the clump. We attribute these sources as the second-generation stars of the complex. We propose that the star formation in the clump is either induced or being facilitated by the compression of the expanding H ii region onto the inflowing filamentary material. [ABSTRACT FROM AUTHOR]

We present the 360° catalogue of physical properties of Hi-GAL compact sources, detected between 70 and 500  |$\mu$| m. This release not only completes the analogous catalogue previously produced by the Hi-GAL collaboration for −71° ≲ ℓ ≲ 67°, but also meaningfully improves it because of a new set of heliocentric distances, 120 808 in total. About a third of the 150 223 entries are located in the newly added portion of the Galactic plane. A first classification based on detection at 70  |$\mu$| m as a signature of ongoing star-forming activity distinguishes between protostellar sources (23 per cent of the total) and starless sources, with the latter further classified as gravitationally bound (pre-stellar) or unbound. The integral of the spectral energy distribution, including ancillary photometry from λ = 21 to 1100  |$\mu$| m, gives the source luminosity and other bolometric quantities, while a modified blackbody fitted to data for |$\lambda \ge 160~\mu$| m yields mass and temperature. All tabulated clump properties are then derived using photometry and heliocentric distance, where possible. Statistics of these quantities are discussed with respect to both source Galactic location and evolutionary stage. No strong differences in the distributions of evolutionary indicators are found between the inner and outer Galaxy. However, masses and densities in the inner Galaxy are on average significantly larger, resulting in a higher number of clumps that are candidates to host massive star formation. Median behaviour of distance-independent parameters tracing source evolutionary status is examined as a function of the Galactocentric radius, showing no clear evidence of correlation with spiral arm positions. [ABSTRACT FROM AUTHOR]

Human activity along the Amalfi coastline in Italy has been tied to the sea for millennia – for sustenance, migration, trade, warfare, and leisure. As a result, this region has an equally rich and extensive maritime cultural landscape composed of tangible and intangible elements. In 2016, a multi-disciplinary project began efforts to model and to understand changes within this landscape, and this essay presents the preliminary results of our first three seasons of work. Some efforts, such as the documentation of maritime cultural heritage in local museums, archival work, and geomorphological research proceeded smoothly. Unexpectedly, however, little material from the pre-modern era was found under water, adding questions to this study that future work in the Marine Protected Area west of Positano may answer. [ABSTRACT FROM AUTHOR]

The glare effect is a brightness illusion that has captured the attention of the vision community since its discovery. However, its photometrical reversal, which we refer to here as photometrical reversed glare (PRG) stimuli, remained relatively unexplored. We presented three experiments that sought to examine the perceived brightness of a target area surrounded by luminance gradients in PRG stimuli and compare them with conventional glare effect configurations. Experiment 1 measured the brightness of the central target area of PRG stimuli through an adjustment task; the results showed that the target appeared brighter than similar, comparative areas not surrounded by luminance gradients. This finding was unexpected given the recent report that PRG stimuli cause pupil dilation. Meanwhile, Experiments 2 and 3 implemented a rating task to further test the findings in Experiment 1. Again, the study found a robust brightening illusion in the target area of PRG stimuli in a wide range of target and background luminance. The results are discussed in comparison with the brightness enhancement of the glare effect. [ABSTRACT FROM AUTHOR]

Aims. Our goal is to better understand the origin and the star-formation history of regions NGC 6334 and NGC 6357. We focus our study on the kinematics of young stars (young stellar objects and OB stars) in both regions mainly on the basis of the Gaia DR2 data. Methods. For both regions, we compiled catalogs of OB stars and young stellar objects from the literature and complemented them using VPHAS+ DR2 and Spitzer IRAC/GLIMPSE photometry catalogues. We applied a cross-match with the Gaia DR2 catalog to obtain information on the parallax and transverse motion. Results. We confirm that NGC 6334 and NGC 6357 are in the far side of the Saggitarius-Carina arm at a distance of 1.76 kpc. For NGC 6357, OB stars show strong clustering and ordered star motion with Vlon ∼–10.7 km s−1 and Vlat ∼3.7 km s−1, whereas for NGC 6334, no significant systemic motion was observed. The OB stars motions and distribution in NGC 6334 suggest that it should be classified as an association. Ten runaway candidates may be related to NGC 6357 and two to NGC 6334, respectively. The spatial distributions of the runaway candidates in and around NGC 6357 favor a dynamical (and early) ejection during the cluster(s) formation. Because such stars are likely to be ejected during a cluster's formation, the fact that not as many such stars are observed towards NGC 6334 suggests different formation conditions than have been assumed for NGC 6357. [ABSTRACT FROM AUTHOR]

To search for the potential chemical dependence on physical conditions, we have carried out the study of chemistry on the nine protostellar clumps of the high-mass star-forming infrared dark cloud G034.43+00.24, with observations of several ∼1 mm lines by the Atacama Pathfinder EXperiment telescope. They include CO/13CO/C18O (2−1), HCO+/H13CO+ (3−2), HCN/H13CN (3−2), HNC (3−2), CS/C34S (5−4), SiO (6−5), SO (6−5), p-H2CO (3−2), and CH3OH (5−4). All the clumps are simply grouped into two classes: high-luminosity protostellar clumps (MM1–MM4, L⊙) and low-luminosity protostellar clumps (MM5–MM9, L⊙). Our observations indicate that 13CO suffers either no or low depletion in the clump environment of G034.43+00.24 as characterized by a nearly constant level of the 13CO abundance distribution. For the remaining relatively dense gas tracers, we find that their abundances tend to get enhanced in the high-luminosity protostellar clumps as opposed to the low-luminosity counterparts. We suggest that for most, if not all, of the dense gas tracers the high abundance mainly arises from both the high luminosities and associated outflows of the high-luminosity protostellar clumps while the low abundance could be due to the lack of such active star-forming activities in the low-luminosity protostellar clumps. [ABSTRACT FROM AUTHOR]

The mass growth of protostars is a central element to the determination of fundamental stellar population properties such as the initial mass function. Constraining the accretion history of individual protostars is therefore an important aspect of star formation research. The goal of the study presented here is to determine whether high-mass (proto)stars gain their mass from a compact (<0.1 pc) fixed-mass reservoir of gas, often referred to as dense cores, in which they are embedded, or whether the mass growth of high-mass stars is governed by the dynamical evolution of the parsec-scale clump that typically surrounds them. To achieve this goal, we performed a 350- μ m continuum mapping of 11 infrared dark clouds, along side some of their neighbouring clumps, with the ArTéMiS camera on APEX. By identifying about 200 compact ArTéMiS sources, and matching them with Herschel Hi-GAL 70 - μ m sources, we have been able to produce mass versus temperature diagrams. We compare the nature (i.e. starless or protostellar) and location of the ArTéMiS sources in these diagrams with modelled evolutionary tracks of both core-fed and clump-fed accretion scenarios. We argue that the latter provide a better agreement with the observed distribution of high-mass star-forming cores. However, a robust and definitive conclusion on the question of the accretion history of high-mass stars requires larger number statistics. [ABSTRACT FROM AUTHOR]

The purpose of this research is to present the employment of a simple-to-use crossmodal method for measuring haptic size illusions. The method, that we call See what you feel, was tested by employing Uznadze's classic haptic aftereffect in which two spheres physically identical (test spheres) appear different in size after that the hands holding them underwent an adaptation session with other two spheres (adapting spheres), one bigger and the other smaller than the two test spheres. To measure the entity of the illusion, a three-dimensional visual scale was created and participants were asked to find on it the spheres that corresponded in size to the spheres they were holding in their hands out of sight. The method, tested on 160 right-handed participants, is robust and easily understood by participants. [ABSTRACT FROM AUTHOR]

We present the properties of magnetic fields (B fields) in two clumps (clump 1 and clump 2), located at the waist of the bipolar H ii region Sh 2-201, based on James Clerk Maxwell Telescope SCUBA-2/POL-2 observations of 850 μm polarized dust emission. We find that B fields in the direction of the clumps are bent and compressed, showing bow-like morphologies, which we attribute to the feedback effect of the H ii region on the surface of the clumps. Using the modified Davis–Chandrasekhar–Fermi method, we estimate B-field strengths of 266 and 65 μG for clump 1 and clump 2, respectively. From virial analyses and critical mass ratio estimates, we argue that clump 1 is gravitationally bound and could be undergoing collapse, whereas clump 2 is unbound and stable. We hypothesize that the interplay of the thermal pressure imparted by the H ii region, the B-field morphologies, and the various internal pressures of the clumps (such as magnetic, turbulent, and gas thermal pressures) has the following consequences: (a) formation of clumps at the waist of the H ii region; (b) progressive compression and enhancement of the B fields in the clumps; (c) stronger B fields that will shield the clumps from erosion by the H ii region and cause pressure equilibrium between the clumps and the H ii region, thereby allowing expanding ionization fronts to blow away from the filament ridge, forming bipolar H ii regions; and (d) stronger B fields and turbulence that will be able to stabilize the clumps. A study of a larger sample of bipolar H ii regions would help to determine whether our hypotheses are widely applicable. [ABSTRACT FROM AUTHOR]

The purpose of this research is to present the employment of a simple-to-use crossmodal method for measuring haptic size illusions. The method, that we call See what you feel, was tested by employing Uznadze's classic haptic aftereffect in which two spheres physically identical (test spheres) appear different in size after that the hands holding them underwent an adaptation session with other two spheres (adapting spheres), one bigger and the other smaller than the two test spheres. To measure the entity of the illusion, a three-dimensional visual scale was created and participants were asked to find on it the spheres that corresponded in size to the spheres they were holding in their hands out of sight. The method, tested on 160 right-handed participants, is robust and easily understood by participants. [ABSTRACT FROM AUTHOR]

The recent data collected by Herschel have confirmed that interstellar structures with a filamentary shape are ubiquitously present in the Milky Way. Filaments are thought to be formed by several physical mechanisms acting from large Galactic scales down to subparsec fractions of molecular clouds, and they might represent a possible link between star formation and the large-scale structure of the Galaxy. In order to study this potential link, a statistically significant sample of filaments spread throughout the Galaxy is required. In this work, we present the first catalogue of 32 059 candidate filaments automatically identified in the Herschel Infrared Galactic plane Survey (Hi-GAL) of the entire Galactic plane. For these objects, we determined morphological (length l a and geometrical shape) and physical (average column density |$N_{\rm H_{2}}$| and average temperature T) properties. We identified filaments with a wide range of properties: 2 ≤ l a ≤ 100 arcmin, |$10^{20} \le N_{\rm H_{2}} \le 10^{23}$|  cm−2 and 10 ≤ T ≤ 35 K. We discuss their association with the Hi-GAL compact sources, finding that the most tenuous (and stable) structures do not host any major condensation. We also assign a distance to ∼18 400 filaments, for which we determine mass, physical size, stability conditions and Galactic distribution. When compared with the spiral arms structure, we find no significant difference between the physical properties of on-arm and inter-arm filaments. We compare our sample with previous studies, finding that our Hi-GAL filament catalogue represents a significant extension in terms of Galactic coverage and sensitivity. This catalogue represents a unique and important tool for future studies devoted to understanding the filament life-cycle. [ABSTRACT FROM AUTHOR]

This contribution mainly focuses on Cyprus and the Balearics, islands located at opposite geographical extremes of the Byzantine Mediterranean, during the passage from Late Antiquity to the early Middle Ages. Historians have often regarded these islands as peripheral additions to the Byzantine heartland of the Aegean and the Anatolian plateau; this article argues that, in fact, archaeological and material indicators (such as ceramics, lead seals and coins), paired with the scarce textual sources, point to a certain degree of economic prosperity in the abovementioned islands during the period under scrutiny, suggesting that they continued to play an important role in the political, administrative and religious structures of the Byzantine Empire. A resilient insular economy and continuity of local production of artefacts was ensured by the persistence of demand from local secular and religious elites and regular, if infrequent, contacts with other areas of the Byzantine heartland or the Muslim Mediterranean. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses articles in the issue on topics including perception of ancient seafaring in the Mediterranean, diminished isolation of islands, and separation facilitated exchange.

Transcranial direct current stimulation (tDCS) has been widely used for modulating sensory, motor and cognitive functions, but there are only few attempts to induce and change illusory perception. Visual illusions have been the most traditional and effective way to investigate visual processing through the comparison between physical reality and subjective reports. Here we used tDCS to modulate two different visual illusions, namely the Brentano illusion and the glare effect, with the aim of uncovering the influence of top-down mechanisms on bottom-up visual perception in two experiments. In Experiment 1, to a first group of subjects, real and sham cathodal tDCS (2 mA, 10 min) were applied over the left and right posterior parietal cortices (PPC). In Experiment 2, real and sham cathodal tDCS were applied to the left and right occipital cortices (OC) to a second group of participants. Results showed that tDCS was effective in modulating only the Brentano illusion, but not the glare effect. tDCS increased the Brentano illusion but specifically for the stimulated cortical area (right PPC), illusion direction (leftward), visual hemispace (left), and illusion length (160 mm). These findings suggest the existence of an inhibitory modulation of top-down mechanisms on bottom-up visual processing specifically for the Brentano illusion, but not for the glare effect. The lack of effect of occipital tDCS should consider the possible role of ocular compensation or of the unstimulated hemisphere, which deserves further investigations. [ABSTRACT FROM AUTHOR]

Aims. We aim to investigate the impact of the ionized radiation from the M 16 H II region on the surrounding molecular cloud and on its hosted star formation. Methods. To present comprehensive multi-wavelength observations towards the M 16 H II region, we used new CO data and existing infrared, optical, and submillimeter data. The 12CO J = 1−0, 13CO J = 1−0, and C18O J = 1−0 data were obtained with the Purple Mountain Observatory (PMO) 13.7 m radio telescope. To trace massive clumps and extract young stellar objects (YSOs) associated with the M 16 H II region, we used the ATLASGAL and GLIMPSE I catalogs, respectively. Results. From CO data, we discern a large-scale filament with three velocity components. Because these three components overlap with each other in both velocity and space, the filament may be made of three layers. The M 16 ionized gas interacts with the large-scale filament and has reshaped its structure. In the large-scale filament, we find 51 compact cores from the ATLASGAL catalog, 20 of them being quiescent. The mean excitation temperature of these cores is 22.5 K, while this is 22.2 K for the quiescent cores. This high temperature observed for the quiescent cores suggests that the cores may be heated by M 16 and do not experience internal heating from sources in the cores. Through the relationship between the mass and radius of these cores, we obtain that 45% of all the cores are massive enough to potentially form massive stars. Compared with the thermal motion, the turbulence created by the nonthermal motion is responsible for the core formation. For the pillars observed towards M 16, the H II region may give rise to the strong turbulence. [ABSTRACT FROM AUTHOR]

Aims. To constrain models of high-mass star formation it is important to identify the massive dense cores (MDCs) that are able to form high-mass star(s). This is one of the purposes of the Herschel/HOBYS key programme. Here, we carry out the census and characterise of the properties of the MDCs population of the NGC 6357 H II region. Methods. Our study is based on the Herschel/PACS and SPIRE 70−500 μm images of NGC 6357 complemented with (sub-)millimetre and mid-infrared data. We followed the procedure established by the Herschel/HOBYS consortium to extract ~0.1 pc massive dense cores using the getsources software. We estimated their physical parameters (temperatures, masses, luminosities) from spectral energy distribution (SED) fitting. Results. We obtain a complete census of 23 massive dense cores, amongst which one is found to be IR-quiet and twelve are starless, representing very early stages of the star-formation process. Focussing on the starless MDCs, we have considered their evolutionary status, and suggest that only five of them are likely to form a high-mass star. Conclusions. We find that, contrarily to the case in NGC 6334, the NGC 6357 region does not exhibit any ridge or hub features that are believed to be crucial to the massive star formation process. This study adds support for an empirical model in which massive dense cores and protostars simultaneously accrete mass from the surrounding filaments. In addition, the massive star formation in NGC 6357 seems to have stopped and the hottest stars in Pismis 24 have disrupted the filaments. [ABSTRACT FROM AUTHOR]

Context. The star formation process requires the dust and gas present in the Milky Way to self-assemble into dense reservoirs of neutral material where the new generation of stars will emerge. Star-forming regions are usually studied in the context of Galactic surveys, but dedicated observations are sometimes needed when the study reaches beyond the survey area. Aims. A better understanding of the star formation process in the Galaxy can be obtained by studying several regions. This allows increasing the sample of objects (clumps, cores, and stars) for further statistical works and deeper follow-up studies. Here, we studied the G345.5+1.5 region, which is located slightly above the Galactic plane, to understand its star formation properties. Methods. We combined Large Apex BOlometer CAmera (LABOCA) and 12CO(4−3) transition line (NANTEN2) observations complemented with the Hi-GAL and Spitzer-GLIMPSE surveys to study the star formation toward this region. We used the Clumpfind algorithm to extract the clumps from the 870 μm and 12CO(4−3) data. Radio emission at 36 cm was used to estimate the number of H II regions and to remove the contamination from the free–free emission at 870 μm. We employed color–color diagrams and spectral energy distribution (SED) slopes to distinguish between prestellar and protostellar clumps. We studied the boundedness of the clumps through the virial parameter. Finally, we estimated the star formation efficiency (SFE) and star formation rate (SFR) of the region and used the Schmidt–Kennicutt diagram to compare its ability to form stars with other regions of the Galactic plane. Results. Of the 13 radio sources that we found using the MGPS-2 catalog, 7 are found to be associated with H II regions corresponding to late-B or early-O stars. We found 45 870 μm clumps with diameters between 0.4 and 1.2 pc and masses between 43 M⊙ and 3923 M⊙, and 107 12CO clumps with diameters between 0.4 and 1.3 pc and masses between 28 M⊙ and 9433 M⊙. More than 50% of the clumps are protostellar and bounded and are able to host (massive) star formation. High SFR and SFR density (ΣSFR) values are associated with the region, with an SFE of a few percent. Conclusions. With submillimeter, CO transition, and short-wavelength infrared observations, our study reveals a population of massive stars, protostellar and bound starless clumps, toward G345.5+1.5. This region is therefore actively forming stars, and its location in the starburst quadrant of the Schmidt–Kennicutt diagram is comparable to other star-forming regions found within the Galactic plane. [ABSTRACT FROM AUTHOR]

Context. The formation of high-mass stars remains unknown in many aspects. There are two competing families of models to explain the formation of high-mass stars. On the one hand, quasi-static models predict the existence of high-mass pre-stellar cores sustained by a high degree of turbulence. On the other hand, competitive accretion models predict that high-mass proto-stellar cores evolve from low or intermediate mass proto-stellar cores in dynamic environments. Aims. The aim of the present work is to bring observational constraints at the scale of high-mass cores (~0.03 pc). Methods. We targeted with ALMA and MOPRA a sample of nine starless massive dense cores (MDCs) discovered in a recent Herschel/HOBYS study. Their mass and size (~110 M⊙ and r = 0.1 pc, respectively) are similar to the initial conditions used in the quasi-static family of models explaining for the formation of high-mass stars. We present ALMA 1.4 mm continuum observations that resolve the Jeans length (λJeans ~ 0.03 pc) and that are sensitive to the Jeans mass (MJeans ~ 0.65 M⊙) in the nine starless MDCs, together with ALMA-12CO(2–1) emission line observations. We also present HCO+(1–0), H13CO+(1–0) and N2H+(1–0) molecular lines from the MOPRA telescope for eight of the nine MDCs. Results. The nine starless MDCs have the mass reservoir to form high-mass stars according to the criteria by Baldeschi et al. (2017). Three of the starless MDCs are subvirialized with αvir ~ 0.35, and four MDCs show sign of collapse from their molecular emission lines. ALMA observations show very little fragmentation within the MDCs. Only two of the starless MDCs host compact continuum sources, whose fluxes correspond to <3 M⊙ fragments. Therefore, the mass reservoir of the MDCs has not yet been accreted onto compact objects, and most of the emission is filtered out by the interferometer. Conclusions. These observations do not support the quasi-static models for high-mass star formation since no high-mass pre-stellar core is found in NGC 6334. The competitive accretion models, on the other hand, predict a level of fragmentation much higher than what we observe. [ABSTRACT FROM AUTHOR]

Byzantine historiography has often regarded the large Mediterranean islands (Cyprus, Crete, Sardinia, Malta and the Balearics) as mere peripheral additions to the Byzantine heartland - defined as the coupling of two different geographical zones: the Anatolian plateau and the Aegean. As a result, Byzantinists seem not to have fully moved away from an interpretative framework which regards islands as either strategic military bulwarks along the Arab-Byzantine Mediterranean frontier, or as neglected marginal outposts soon to be lost forever. A partial exception to this historiographical periphericity of large islands is represented by Sicily, because of its relevance as a secure source for grain after the disruption of the Egyptian tax-spine in the 640s. In fact, by comparing material and archaeological evidence with literary and documentary sources, an alternative interpretation of the political, economic and cultural role played by large islands will be proposed, this by pairing two main themes: the first revolving around the economics of insular societies; and the second stressing the importance of islands as connective hubs with peculiar local political, social and cultural structures which remained within the Byzantine sphere of influence for longer than previously thought. This approach allows us to tip the unbalanced dialogue between margins and metropolis by pointing to a relatively higher welfare of the insular world as stemming from the uninterrupted, although diminished, "connective" role the abovementioned islands played within the Mediterranean shipping routes linking the eastern and western basin of the Mediterranean. In this light, the adaptive strategies of insular administrative structures as influenced by the political or military difficulties of the hour, as well as the urban socio-political and economic structures on some of the abovementioned Byzantine islands, will also be documented. This is because the construction of urban models, settlement strategies and infrastructures - although often based on diverse political and administrative policies - nevertheless point to the presence of common, cross-cultural insular developments such as: the role of members of urban-oriented aristocracies as cultural brokers; the creation of commercial and artisanal facilities; the construction or restoration of religious buildings as foci of settlement and regional as well as interregional pilgrimage; the resilience of local elites as catalysts of patronage; and the persistence of levels of demand often based upon regular if not frequent regional and sub-regional trans-maritime contacts. [ABSTRACT FROM AUTHOR]

This work concerns the subjective impression of perceived illumination. The purpose of the study is to test attributes expressing qualitative experiences referring to ambient lighting that can be applied as descriptors. Seventy participants viewed an actual model room, with the fourth wall removed (viewing booth). Walls, floor, and ceiling were achromatic. Two achromatic cubes were placed inside the room: One was a reflectance increment to the walls, the other a decrement. The room was illuminated by two different light sources, Artificial Daylight (D65) or Tungsten Filament (F), the order of which was randomized across participants. The participants' task was to evaluate ambient illumination for each light source. A semantic differential method was employed with 27 pairs of adjectives on 1 to 7 rating scales, categorized in three groups: characteristics of atmosphere, time, and cross-modal. Only the ratings of nine pairs of adjectives were not influenced by the type of illumination. The most differentiated couples under different illuminants were hot/cold and modern/old, but large differences also appeared with the following couples: hard/soft, technological/primitive, summery/wintry, warm/cool, sensual/frigid, natural/artificial, and hospitable/inhospitable. The hypothesis that there would be consistency among the subjects in evaluations of the characteristics tested and that these would be differently perceived under different illuminants was confirmed. The results show that it is possible to identify subjective perceived illumination as a phenomenon endowed with specific filling-in qualities and that as a perceptual experience it can be categorized, with implications for application in architecture and design. [ABSTRACT FROM AUTHOR]

Aims. We aim to identify bipolar Galactic H II regions and to understand their parental cloud structures, morphologies, evolution, and impact on the formation of new generations of stars. Methods. We use the Spitzer-GLIMPSE, Spitzer-MIPSGAL, and Herschel-Hi-GAL surveys to identify bipolar H II regions and to examine their morphologies. We search for their exciting star(s) using NIR data from the 2MASS, UKIDSS, and VISTA surveys. Massive molecular clumps are detected near these bipolar nebulae, and we estimate their temperatures, column densities, masses, and densities. We locate Class 0/I young stellar objects (YSOs) in their vicinities using the Spitzer and Herschel-PACS emission. Results. Numerical simulations suggest bipolar H II regions form and evolve in a two-dimensional flat- or sheet-like molecular cloud. We identified 16 bipolar nebulae in a zone of the Galactic plane between ℓ ± 60° and |b| < 1°. This small number, when compared with the 1377 bubble H II regions in the same area, suggests that most H II regions form and evolve in a three-dimensional medium. We present the catalogue of the 16 bipolar nebulae and a detailed investigation for six of these. Our results suggest that these regions formed in dense and flat structures that contain filaments. We find that bipolar H II regions have massive clumps in their surroundings. The most compact and massive clumps are always located at the waist of the bipolar nebula, adjacent to the ionised gas. These massive clumps are dense, with a mean density in the range of 105 cm−3 to several 106 cm−3 in their centres. Luminous Class 0/I sources of several thousand solar luminosities, many of which have associated maser emission, are embedded inside these clumps. We suggest that most, if not all, massive 0/I YSO formation has probably been triggered by the expansion of the central bipolar nebula, but the processes involved are still unknown. Modelling of such nebula is needed to understand the star formation processes at play. [ABSTRACT FROM AUTHOR]

Aims. The formation of high-mass stars is still debated. For this reason, several projects such as Herschel-HOBYS are focussed on the study of the earliest phases of massive star formation. As a result, massive star-forming complexes such as NGC 6334 and NGC 6357 have been observed in the far-infrared to study their massive dense cores where massive stars are expected to form. However, to better characterise the environments of these cores we need to understand the previous massive star formation history. To better characterise the environment of these massive dense cores we study the previous high-mass star formation and how these stars act on their environments. Methods. This study is based on the spectral classification of the OB stars identified towards NGC 6334 and NGC 6357 with spectra taken with the AAOmega spectrograph on the Anglo-Australian Telescope (AAT). From the subsequent spectral classification of 109 stars across these regions we were able to evaluate the following: distance, age, mass, global star-forming efficiency (SFE), and star formation rate (SFR) of the regions. The physical conditions of the ionised gas for both complexes was also derived. Results.We confirm that NGC 6334 and NGC 6357 belong to the Saggitarius-Carina arm which, in this direction, extends from 1 kpc to 2.2 kpc. From the location of the stars in Hertzprung-Russell diagram we show that stars older than ~10 Myr are broadly spread across these complexes, while younger stars are mainly located in the H II regions and stellar clusters. Our data also suggests that some of the young stars can be considered runaway stars. We evaluate a SFE of 0.019+0:008 -0:007 and 0.021+0:004 -0:003 and a SFR of 1:1 X 103 ± 300 M☉Myr-1 and 1:7 X 103 ± 400 M☉ Myr-1 for NGC 6334 and NGC 6357, respectively. We note that 29 OB stars have X-ray counterparts, most of them belonging to NGC 6357. This suggests that molecular clouds in NGC 6357 are more impacted by X-ray flux and stellar winds than in NGC 6334. Finally, from the analysis of nebular lines (H , [NII], and [SII]) from spectra from several regions of ionised gas, we confirm that the filaments in NGC 6357 are shock heated. [ABSTRACT FROM AUTHOR]

We present a comprehensive statistical analysis of star-forming objects located in the vicinities of 1 360 bubble structures throughout the Galactic Plane and their local environments. The compilation of ~70 000 star-forming sources, found in the proximity of the ionized (Hii) regions and detected in both Hi-GAL and GLIMPSE surveys, provided a broad overview of the different evolutionary stages of star-formation in bubbles, from prestellar objects to more evolved young stellar objects (YSOs). Surface density maps of star-forming objects clearly reveal an evolutionary trend where more evolved star-forming objects are found spatially located near the center, while younger star-forming objects are found at the edge of the bubbles. We derived dynamic ages for a subsample of 182 Hii regions for which kinematic distances and radio continuum flux measurements were available. We detect ~80% more star-forming sources per unit area in the direction of bubbles than in the surrounding fields. We estimate ~10% clump formation efficiency (CFE) of Hi-GAL clumps in bubbles, twice the CFE in fields not affected by feedback. We find higher CFE of protostellar clumps in younger bubbles, whose density of the bubble shells is higher. We argue that the formation rate from prestellar to protostellar phase is probably higher during the early stages of the bubble expansion. Evaluation of the fragmentation time inside the shell of bubbles advocates the preexistence of clumps in the medium before the bubble, as supported by numerical simulations. Approximately 23% of the Hi-GAL clumps are found located in the direction of a bubble, with 15% for prestellar clumps and 41% for protostellar clumps. We argue that the high fraction of protostellar clumps may be due to the acceleration of the star-formation process cause by the feedback of the (Hii) bubbles. [ABSTRACT FROM AUTHOR]

Context. Triggered star formation around Hii regions could be an important process. The Galactic Hii region RCW79 is a prototypical object for triggered high-mass star formation. Aims. We aim to obtain a census of the young stellar population observed at the edges of the Hii region and to determine the properties of the young sources in order to characterize the star formation processes that take place at the edges of this ionized region. Methods. We take advantage of Herschel data from the surveys HOBYS, "Evolution of Interstellar Dust", and Hi-Gal to extract compact sources. We use the algorithm getsources. We complement the Herschel data with archival 2MASS, Spitzer, and WISE data to determine the physical parameters of the sources (e.g., envelope mass, dust temperature, and luminosity) by fitting the spectral energy distribution. Results. We created the dust temperature and column density maps along with the column density probability distribution function (PDF) for the entire RCW79 region. We obtained a sample of 50 compact sources in this region, 96% of which are situated in the ionization-compressed layer of cold and dense gas that is characterized by the column density PDF with a double-peaked lognormal distribution. The 50 sources have sizes of ~0.1-0.4 pc with a typical value of ~0.2 pc, temperatures of ~11-26 K, envelope masses of ~6-760 M⊙, densities of ~0.1-44 × 105 cm-3, and luminosities of ~19-12 712 L⊙. The sources are classified into 16 class 0, 19 intermediate, and 15 class I objects. Their distribution follows the evolutionary tracks in the diagram of bolometric luminosity versus envelope mass (Lbol - Menv) well. A mass threshold of 140 M⊙, determined from the Lbol - Menv diagram, yields 12 candidate massive dense cores that may form high-mass stars. The core formation efficiency (CFE) for the 8 massive condensations shows an increasing trend of the CFE with density. This suggests that the denser the condensation, the higher the fraction of its mass transformation into dense cores, as previously observed in other high-mass star-forming regions. [ABSTRACT FROM AUTHOR]

Aims. To constrain models of high-mass star formation, the Herschel-HOBYS key program aims at discovering massive dense cores (MDCs) able to host the high-mass analogs of low-mass prestellar cores, which have been searched for over the past decade. We here focus on NGC 6334, one of the best-studied HOBYS molecular cloud complexes. Methods. We used Herschel/PACS and SPIRE 70-500 μm images of the NGC 6334 complex complemented with (sub)millimeter and mid-infrared data. We built a complete procedure to extract ~0.1 pc dense cores with the getsources software, which simultaneously measures their far-infrared to millimeter fluxes. We carefully estimated the temperatures and masses of these dense cores from their spectral energy distributions (SEDs). We also identified the densest pc-scale cloud structures of NGC 6334, one 2 pc × 1 pc ridge and two 0.8 pc × 0.8 pc hubs, with volume-averaged densities of ~105 cm-3. Results. A cross-correlation with high-mass star formation signposts suggests a mass threshold of 75 M⊙ for MDCs in NGC 6334. MDCs have temperatures of 9:5-40 K, masses of 75-1000 M⊙, and densities of 1 × 105-7 × 107 cm-3. Their mid-infrared emission is used to separate 6 IR-bright and 10 IR-quiet protostellar MDCs while their 70 μm emission strength, with respect to fitted SEDs, helps identify 16 starless MDC candidates. The ability of the latter to host high-mass prestellar cores is investigated here and remains questionable. An increase in mass and density from the starless to the IR-quiet and IR-bright phases suggests that the protostars and MDCs simultaneously grow in mass. The statistical lifetimes of the high-mass prestellar and protostellar core phases, estimated to be 1-7 × 104 yr and at most 3 × 105 yr respectively, suggest a dynamical scenario of high-mass star formation. Conclusions. The present study provides good mass estimates for a statistically significant sample, covering the earliest phases of high-mass star formation. High-mass prestellar cores may not exist in NGC 6334, favoring a scenario presented here, which simultaneously forms clouds, ridges, MDCs, and high-mass protostars. [ABSTRACT FROM AUTHOR]

The Herschel survey of the Galactic Plane (Hi-GAL) is a continuum Galactic plane survey in five wavebands at 70, 160, 250, 350 and 500 µm. From such images, about 150 000 sources have been extracted for which the distance determination is a challenge. In this context the velocity of these sources has been determined thanks to a large number of molecular data cubes. But to convert the velocity to kinematic distance, one needs to adopt a rotation curve for our Galaxy. For three different samples of tracers, we test different analytical forms. We find that the power-law expression, θ(R)/θ0 = 1.022 (R/R0)0.0803 with R0, θ0 = 8.34 kpc, 240 kms-1 is a good and easily manipulated expression for the distance determination process. [ABSTRACT FROM AUTHOR]

Context. The expansion of Hii regions can trigger the formation of stars. An overdensity of young stellar objects is observed at the edges of Hii regions but the mechanisms that give rise to this phenomenon are not clearly identified. Moreover, it is difficult to establish a causal link between Hii -region expansion and the star formation observed at the edges of these regions. A clear age gradient observed in the spatial distribution of young sources in the surrounding might be a strong argument in favor of triggering. Aims. We aim to characterize the star formation observed at the edges of Hii regions by studying the properties of young stars that form there. We aim to detect young sources, derive their properties and their evolution stage in order to discuss the possible causal link between the first-generation massive stars that form the Hii region and the young sources observed at their edges. Methods. We have observed the Galactic Hii region RCW 120 with Herschel PACS and SPIRE photometers at 70, 100, 160, 250, 350 and 500 µm. We produced temperature and H2 column density maps and use the getsources algorithm to detect compact sources and measure their fluxes at Herschel wavelengths. We have complemented these fluxes with existing infrared data. Fitting their spectral energy distributions with a modified blackbody model, we derived their envelope dust temperature and envelope mass. We computed their bolometric luminosities and discuss their evolutionary stages. Results. The overall temperatures of the region (without background subtraction) range from 15 K to 24 K. The warmest regions are observed towards the ionized gas. The coldest regions are observed outside the ionized gas and follow the emission of the cold material previously detected at 870 mand 1.3 mm. The H2 column density map reveals the distribution of the cold medium to be organized in filaments and highly structured. Column densities range from 7 × 1021 cm-2 up to 9 × 1023 cm-2 without background subtraction. The cold regions observed outside the ionized gas are the densest and host star formation when the column density exceeds 2 × 1022 cm-2. The most reliable 35 compact sources are discussed. Using existing CO data and morphological arguments we show that these sources are likely to be associated with the RCW 120 region. These sources' volume densities range from 2 × 105 cm-3 to 108 cm-3. Five sources have envelope masses larger than 50 M∡ and are all observed in high column density regions (>7 × 1022 cm-2). We find that the evolutionary stage of the sources primarily depends on the density of their hosting condensation and is not correlated with the distance to the ionizing star. Conclusions. The Herschel data, with their unique sampling of the far infrared domain, have allowed us to characterize the properties of compact sources observed towards RCW 120 for the first time. We have also been able to determine the envelope temperature, envelope mass and evolutionary stage of these sources. Using these properties we have shown that the density of the condensations that host star formation is a key parameter of the star-formation history, irrespective of their projected distance to the ionizing stars. [ABSTRACT FROM AUTHOR]

The paper presents the map of intrinsic groundwater vulnerability of the Isonzo/Soča High Plain, which is located between the Collio Hills and the Classical Karst Region and holds an aquifer shared between Italy and Slovenia. The map, produced at a scale of 1:25,000 and printed in A0 format, was obtained by means of the SINTACS method and shows the intrinsic vulnerability of the aquifer in terms of seven vulnerability classes, from extremely high to low. It is accompanied by four supplementary sketches that illustrate the geological framework, the bedrock top surface, the groundwater flow paths, the Hazard Index map and three diagrams that summarize the percentages of vulnerability classes and of Hazard Index classes of the study area. [ABSTRACT FROM PUBLISHER]

Objective: The aim of our study was to investigate which text-background (TB) color combinations improve legibility and pleasantness of texts either presented on a computer screen or projected on a wider surface.Background: Our work stems from the observation that multimedia presentations, even those by professionals in visual disciplines, are often spoiled by illegibility, which affects readability and the pleasantness of attending to such presentations.Methods: We investigated this problem through three experiments. Experiment 1 assessed the best TB color combinations in slides presented on a laptop. Experiment 2 verified the correlation between legibility and pleasantness for TB presentations. Experiment 3 investigated the legibility of a slide projected on a wide screen in different room lighting conditions. In all experiments participants expressed a rating score for stimulus legibility or pleasantness.Results: Experiments 1 and 3 showed that it is best to have a dark text on a light background for both displayed and projected texts. Experiment 2 showed that pleasantness is tightly correlated with legibility, though legibility depends on contrast between text and background.Conclusions: Our findings are not in complete agreement with the literature concerning legibility of text displayed on a computer screen, and they are in contrast with the common belief that for projection purposes it is best to have a light text on a dark background.Applications: Some practical rules on combining TB colors are given to enhance the legibility of presentations, especially important for the legibility of projected texts. [ABSTRACT FROM AUTHOR]

Context. The surroundings of H II regions can have a profound influence on their development, morphology, and evolution. This paper explores the effect of the environment on H II regions in the MonR2 molecular cloud. Aims. We aim to investigate the density structure of envelopes surrounding H II regions and to determine their collapse and ionisation expansion ages. The Mon R2 molecular cloud is an ideal target since it hosts an H II region association, which has been imaged by the Herschel PACS and SPIRE cameras as part of the HOBYS key programme. Methods. Column density and temperature images derived from Herschel data were used together to model the structure of H II bubbles and their surrounding envelopes. The resulting observational constraints were used to follow the development of the Mon R2 ionised regions with analytical calculations and numerical simulations. Results. The four hot bubbles associated with H II regions are surrounded by dense, cold, and neutral gas envelopes, which are partly embedded in filaments. The envelope's radial density profiles are reminiscent of those of low-mass protostellar envelopes. The inner parts of envelopes of all four H II regions could be free-falling because they display shallow density profiles: ρ(r) ∝ r-q with q ≤ 1:5. As for their outer parts, the two compact H II regions show a ρ(r) ∝ r-2 profile, which is typical of the equilibrium structure of a singular isothermal sphere. In contrast, the central UCH II region shows a steeper outer profile, ρ(r) ∝ r-2.5, that could be interpreted as material being forced to collapse, where an external agent overwhelms the internal pressure support. Conclusions. The size of the heated bubbles, the spectral type of the irradiating stars, and the mean initial neutral gas density are used to estimate the ionisation expansion time, texp ∼ 0:1 Myr, for the dense UCH II and compact H II regions and ∼0:35 Myr for the extended H II region. Numerical simulations with and without gravity show that the so-called lifetime problem of H II regions is an artefact of theories that do not take their surrounding neutral envelopes with slowly decreasing density profiles into account. The envelope transition radii between the shallow and steeper density profiles are used to estimate the time elapsed since the formation of the first protostellar embryo, tinf ∼ 1 Myr, for the ultra-compact, 1:5-3 Myr for the compact, and greater than ∼6 Myr for the extended H II regions. These results suggest that the time needed to form a OB-star embryo and to start ionising the cloud, plus the quenching time due to the large gravitational potential amplified by further in-falling material, dominates the ionisation expansion time by a large factor. Accurate determination of the quenching time of H II regions would require additional small-scale observationnal constraints and numerical simulations including 3D geometry effects. [ABSTRACT FROM AUTHOR]

Context. The expansion of Galactic H II regions can trigger the formation of a new generation of stars. However, little is know about the physical conditions that prevail in these regions. Aims. We study the physical conditions that prevail in specific zones towards expanding H II regions that trace representative media such as the photodissociation region, the ionized region, and condensations with and without ongoing star formation. Methods. We use the SPIRE Fourier Transform Spectrometer (FTS) on board Herschel to observe the H II region RCW 120. Continuum and lines are observed in the 190-670 μm range. Line intensities and line ratios are obtained and used as physical diagnostics of the gas. We used the Meudon PDR code and the RADEX code to derive the gas density and the radiation field at nine distinct positions including the PDR surface and regions with and without star-formation activity. Results. For the different regions we detect the atomic lines [NII] at 205 μm and [CI] at 370 and 609 μm, the 12CO ladder between the J = 4 and J = 13 levels and the 13CO ladder between the J = 5 and J = 14 levels, as well as CH+ in absorption. We find gas temperatures in the range 45-250 K for densities of 104-106 cm-3, and a high column density on the order of NH ~ 1022 cm-2 that is in agreement with dust analysis. The ubiquitousness of the atomic and CH+ emission suggests the presence of a low-density PDR throughout RCW 120. High-excitation lines of CO indicate the presence of irradiated dense structures or small dense clumps containing young stellar objects, while we also find a less dense medium (NH ~ 1020 cm-2) with high temperatures (80-200 K). [ABSTRACT FROM AUTHOR]

This paper is about the Poggendorff illusion in pictorial artworks. In particular, it deals with the role played by the Poggendorff illusion in the making of the geometrical misalignments in the mosaic known as Lunetta di San Lorenzo in Ravenna (Italy) and in Rubens's oil on panel Descent from the Cross in Antwerp (Belgium). Three experiments are presented. Experiment 1 tested the role of viewing distance in perceived collinearity in the mosaic by asking participants to adjust two ends of a cross in silhouette renderings of the saint projected so to mimic its original size. Results confirm an effect of viewing distance and support the hypothesis that the author of the mosaic became aware of the illusion and attempted to 'fix' it. Experiment 2 aimed at verifying perceived collinearity in a book-size version of Rubens's Descent from the Cross by employing a similar adjustment method. Results demonstrate that the Poggendorff illusion affects perceived collinearity in the painting, but perceptual collinearity does not agree with the actual geometrical misalignment in book-size reproductions of the masterpiece. Experiment 3 tested the role of viewing distance in a classic Poggendorff illusion configuration by employing the same setup as in experiment 1. Contrary to what was found in experiment 1, viewing distance did not modulate the magnitude of the illusion in the classic display, suggesting that the outcome of perceived collinearity is sensitive to the complexity of the visual scene. The difference in results between experiments 1 and 3 underscore the necessity of new tests before any reasonable conclusion can be drawn about the whys and wherefores of Rubens's misalignment. [ABSTRACT FROM AUTHOR]

An experiment is presented, aimed at preliminary testing the hypothesis according to which facial expressions related to specific emotions, such as anger, fear, and joy, incorporate a sense of dynamicity and are used to enhance the representation of motion in static artworks. Since a growing body of evidence shows that motion is one of the core components of emotion, and the representation of motion in art is often achieved by portraying unstable poses, we hypothesize that the visually more dynamic emotions are those with 'unstable' facial expressions, i.e., expressions that imply muscular tensions that cannot be held for long (e.g., rage, grief, amazement: E-motions) whereas static emotions are those which can last and even represent a constant facial feature in some people. To test this hypothesis we chose eleven static artworks from which we derived twelve human figures that convey different emotions in different proportions. Images were manipulated to produce two sets of stimuli: headless bodies (Set 1) and bodiless heads (Set 2). Participants were asked to rate perceived dynamicity of stimuli from Set 1 on a 7-point Likert scale (Session 1) and to rate each stimulus from Set 2 for joy, sadness, surprise, disgust, anger, fear, serenity, puzzlement and dynamicity (i.e., eight emotions and dynamicity). As expected, we found that some facial emotions (i.e., disgust, anger and fear) are positively related to the dynamicity attributed to the artworks: those emotions are the more sudden ones and thus the more 'unstable'. We also found that serenity is negatively related to dynamicity. Contrary to our expectations, we found instead that joy is statistically different from dynamicity, a result that calls for further investigation. [ABSTRACT FROM AUTHOR]