Dense Center Research Articles

The deep city: cultural heritage as a resource for sustainable local transformation

ABSTRACTThe sustainable city of the future is typically envisioned as smart, creative and disruptive, assuming that urban and local sustainability is achieved through new technology and innovation. However, considering that the built environments of our cities and surroundings are highly durable, there is also a need to focus on how resources brought from the past – histories, artefacts and places – may be used for promoting urban sustainability. We label this a “deep city” perspective on urban and local transformation. By looking at Røros, a World Heritage Site in central Norway with a dense and historic wooden urban centre, we investigate how its heritage protection facilitates the maintenance of a compact urban centre. We hold that a shared sense of place – the deepness– may serve as a resource against unsustainable sprawl and mall-oriented development.

Features of formation of Yersinia enterocolitica biofilms.

Aim:The work aimed to study the morphology of colonies and their comparison by features of the formation of Yersinia enterocolitica biofilms.Materials and Methods:Bacteria were cultured on a Yersinia Selective Agar medium (“CIN-agar”) at 28°C for 24 h. The microorganisms were grown in meat-peptone broth with 1.0% glucose to measure the absolute values of the optical density of the culture. The optical density of the liquid was determined in a microplate photometric analyzer Immunochem-2100 (HTI, USA) at a wavelength of 490 nm. For the study of biofilms, the specimens were fixed for 3-5 h in pairs of 25.0% solution of glutaraldehyde (according to DV), and pairs of a 1.0% aqueous solution of osmic acid (OSO4) were used for contrasting for 2-3 min. The specimens were examined with stereoscopic microscopy “BIOMED MS-1 Stereo” (Russia) and scanning electron microscope “TM 3030 plus” (Holland).Results:With stereoscopic microscopy of the colonies of Y. enterocolitica, the S-forms had an elevated intensely colored center, radial striation along the periphery, smooth edges, d ≤ 1.0 mm. R-form colonies had a dark color and a dry surface, were tuberous and had a dense center with a peripheral ridge, rugged edges, d ≥ 1.5 mm. The optical density of the Y. enterocolitica S-form showed that this type of microorganism belongs to the moderate producers of biofilms since the optical density of the sample (density of the sample - Ds) exceeded the optical density of control (density of the control - Dc) by 3 times. In Y. enterocolitic a R-form (D ≤ 0.197) weakly produced biofilms, the optical density of the sample exceeded the optical density of the control by <2 times.Conclusion:The ability to form biofilms, the variability of phenotypic features, and the multiplicity of virulence factors of bacteria significantly reduce the effectiveness of diagnostic studies. The development of accelerated methods of detection and differentiation of the virulent properties of pathogenic bacteria will allow scientifically to substantiate and develop a set of measures aimed at preventing animal diseases and obtaining safe livestock products to prevent human diseases. Thus, we need to pay attention to which forms of colonies do Y. enterocolitic a form on solid nutrient media: S- or R-forms. Through this study, we know that bacteria-forming S-shaped colonies are more capable of forming biofilms than R-forms. It means that they are more pathogenic and can cause persistent infections due to adhesion and biofilm formation.

Molecular Ionization Rates and Ultracompact Dark Matter Minihalos.

Molecular ionization in the central molecular zone of our Galaxy is enhanced over the typical galactic value by an order of magnitude or more. This cannot be easily explained for dense Galactic center molecular complexes in the absence of embedded sources of low energy cosmic rays. We provide such a source in the form of ultracompact minihalos of self-annihilating dark matter for a variety of annihilation channels that depend on the particle mass and model. Such sources are motivated for plausible inflationary power spectrum parameters, and while possibly subdominant in terms of the total dark matter mass within the Galactic bulge, might also account for, or at least not be in tension with, the Fermi Galactic center γ-ray excess.

Study of Triple Ar Gas Puff Z-Pinches on 0.9-MA, 200-ns COBRA

Ar gas puff z-pinch experiments were conducted on the 0.9-MA, 200-ns COBRA generator at Cornell University. In the experiments, a triple-nozzle gas valve was used to produce the z-pinch load with concentric outer and inner gas puffs and a central gas jet. We used a planer laser-induced fluorescence to measure the initial gas profile of the load, two four-frame 4-ns gated extreme ultraviolet cameras to image the imploding plasma, and filtered photoconducting diamond detectors to measure the X-ray output. We have observed the shock heating and/or photoionization of the dense center jet by the imploding plasma. With an outer-to-inner plenum pressure ratio of 1:3, deacceleration of the imploding plasma occurred when the outer plasma shell imploded on the inner shell resulting in a stable implosion. By varying the plenum pressure for the center jet, the X-ray emission was optimized. An Ar K-shell X-ray (3–4 keV) yield of 77 ± 17 J was produced at a current level of 0.87 ± 0.2 MA and an implosion time of 200 ns.

High-rate lithium cycling in a scalable trilayer Li-garnet-electrolyte architecture

Abstract Solid-state lithium batteries promise to exceed the capabilities of traditional Li-ion batteries in safety and performance. However, a number of obstacles have stood in the path of solid-state battery development, primarily high resistance and low capacity. In this work, these barriers are overcome through the fabrication of a uniquely microstructured solid electrolyte architecture based on a doped Li7La3Zr2O12 (LLZ) ceramic Li-conductor. Specifically, a porous-dense-porous trilayer structure was fabricated by tape casting, a scalable roll-to-roll manufacturing technique. The dense (>99%) center layer can be fabricated as thin as ∼10 μm and blocks dendrites over hundreds of cycles. The microstructured porous layers serve as electrode supports and increase the mechanical strength by ∼9×, making the cells strong enough to handle with ease. Additionally, the porous layers multiply the electrode–electrolyte interfacial surface area by >40× compared to a typical planar interface. Lithium symmetric cells based on the trilayer architecture were cycled at room temperature and achieved area-specific resistances (∼7 Ω-cm2) dramatically lower, and current densities dramatically higher (10 mA/cm2), than previously reported literature results. Moreover, to demonstrate scalability a large-format cell was fabricated with lithium metal in one porous layer and a sulfur electrode with conductive carbon and an ionic liquid interface in the other, achieving 1244 mAh/g S utilization and 195 Wh/kg based on total cell mass, showing a promising path to commercially viable, intrinsically safe lithium batteries with high specific energy and high energy density.

The anterolateral ligament is a distinct ligamentous structure: A histological explanation

BackgroundThe aim was to determine whether the anterolateral ligament (ALL) had a histological structure that defined it as a real ligament. MethodsHistological examination of 30 ALL samples taken from fresh-frozen knees were performed. The ALL femoral insertion and its relationship with the lateral collateral ligament (LCL) were studied and the tibial insertion and its relationship with articular cartilage of the tibial joint surface were analyzed. For the ligamentous part, its histological structure and its differences with the articular capsule were studied. ResultsThis connective tissue is composed of a dense fibrous core constituted by a network of oriented collagenous fibers. The periphery of this dense connective center is made up of loose fibrocollagenous tissue with vascular structures and focal deposits of adipose tissue. This part was in contact but different to the joint capsule.With a perpendicular orientation of the collagen fibers relative to the bone, a fibrocartilaginous zone with an unmineralized hyalinized aspect, a mineralization front, its bone insertions presented a typical ligamentous insertion.With a cleavage plane between ALL and LCL femoral insertion, the ALL appeared to have a femoral insertion distinct from the LCL. ALL tibial insertion was less characteristic with less organized connective tissue and was at a distance from the articular cartilage. ConclusionFrom its bony insertion to its tissue composition and organization, the ALL has all the histological characteristics of a ligamentous structure. Our study confirms that ALL can be considered a real and distinct ligament.

Dust properties of the cometary globule Barnard 207 (LDN 1489)

Barnard 207 (B207, LDN 1489, LBN 777), also known as the Vulture Head nebula, is a cometary globule in the Taurus-Auriga-Perseus molecular cloud region. B207 is known to host a Class I protostar, IRAS 04016+2610, located at a projected distance of ~8,400 au from the dense core centre. Using imaging and photometry over a wide wavelength range, from UV to sub-mm, we study the physical properties of B207 and the dust grains contained within. The core density, temperature, and mass are typical of other globules found in the Milky Way interstellar medium (ISM). The increase in the dust albedo with increasing optical wavelengths, along with the detection of coreshine in the near infrared, indicates the presence of larger dust grains in B207. The measured optical, near-, mid- and far-infrared intensities are in agreement with the CMM+AMM and CMM+AMMI dust grain type of The Heterogeneous dust Evolution Model for Interstellar Solids (THEMIS), suggesting mantle formation on the dust grains throughout the globule. We investigate the possibility of turbulence being responsible for diffusing dust grains from the central core to external outer layers of B207. However, in situ formation of large dust grains cannot be excluded.

On Galvin’s theorem for compact Hausdorff right-topological semigroups with dense topological centers

We generalize an important theorem of Fred Galvin from the Stone-Cech compactification βT of any discrete semigroup T to any compact Hausdorff right-topological semigroup with a dense topological center; and then apply it to Ellis’ semigroups to prove that a point is distal if and only if it is IP*-recurrent, for any semiflow (T;X) with arbitrary compact Hausdorff phase space X not necessarily metrizable and with arbitrary phase semigroup T not necessarily cancelable.

The destruction of an Oort Cloud in a rich stellar cluster

It is possible that the formation of the Oort Cloud dates back to the earliest epochs of solar system history. At that time, the Sun was almost certainly a member of the stellar cluster, where it was born. Since the solar birth cluster is likely to have been massive (1000--10 000 Msol), and therefore long-lived, an issue concerns the survival of such a primordial Oort Cloud. We have investigated this issue by simulating the orbital evolution of Oort Cloud comets for several hundred Myr, assuming the Sun to start its life as a typical member of such a massive cluster. We have devised a synthetic representation of the relevant dynamics, where the cluster potential is represented by a King model, and about 20 close encounters with individual cluster stars are selected and integrated based on the solar orbit and the cluster structure. Thousands of individual simulations are made, each including 3 000 comets with orbits with three different initial semi-major axes. Practically the entire initial Oort Cloud is found to be lost for our choice of semi-major axes (5 000--20 000 au), independent of the cluster mass, although the chance of survival is better for the smaller cluster, since in a certain fraction of the simulations the Sun orbits at relatively safe distances from the dense cluster centre. For the range of birth cluster sizes that we investigate, a primordial Oort Cloud will likely survive only as a small inner core with semi-major axes < 3 000 au. Such a population of comets would be inert to orbital diffusion into an outer halo and subsequent injection into observable orbits. Some mechanism is therefore needed to accomplish this transfer, in case the Oort Cloud is primordial and the birth cluster did not have a low mass. From this point of view, our results lend some support to a delayed formation of the Oort Cloud, that occurred after the Sun had left its birth cluster.

A micro-climatic study on cooling effect of an urban park in a hot and humid climate

The cooling effect of a 4.5ha urban forest park located in a dense city center area in a hot and humid climate was investigated with the three-dimensional microclimate simulation tool ENVI-met v3.1. Dynamic predictions are firstly performed with different wind directions (northerly, southerly, easterly and westerly) for a typical summer day. Then the meteorological data were averaged to eliminate the effect of wind direction, considering equal probability for each wind direction. Overall, when wind speed is 1.5m/s, park cool island (PCI) intensity is about 2°C and the PCI center is offset from the park center if a preponderant prevailing wind direction exists. After eliminating the influence of wind direction by considering equal probability for each wind direction, PCI intensity is about 0.8°C and the PCI center is near to the park center. A higher wind speed would lead to a lower PCI intensity and a smaller area of influence. Compared to air temperature, the spatial distributions of mean radiant temperature and relative humidity are not significantly affected by a preponderant prevailing wind direction. And mean radiant temperature was found to be about 30°C lower in shaded areas of the park.

Demonstration of 4 × 100 Gbps discrete multitone transmission using electric absorption modulated laser at 1550-nm for dense wavelength division multiplexing intradata center connect

We experimentally demonstrate 4 lanes up to 400 Gbps discrete multitone transmission using an electric absorption modulated laser (EML) at 1550-nm for dense wavelength division multiplexing (DWDM) intradata center connects. This is the first demonstration of 4×100 Gb/s transmission using EML at 1550-nm, and it is compatible with the DWDM system at C-band.

Rounded Edges: Modernism and Architectural Dialogue in Ho Chi Minh City

It is widely considered that there is no critical mass of architecture in a homogeneous style in Ho Chi Minh City, in contrast to Hanoi. This essay seeks to establish Ho Chi Minh City’s architectural heritage as a significant one, by arguing that the city does actually possess a critical mass of cohesive, remarkably well-designed buildings in modernist styles. Highlighted here is a unique feature of these modernist buildings: rounded, curved corners as a recurring motif in a dense urban center. The author argues that such buildings, dating from the 1920s through the 1970s, have provided the center of Ho Chi Minh City unique, cohesive, and striking characteristics and that they form one of the great ensembles of modernist architecture anywhere. This essay aims to re-locate the place of Ho Chi Minh City on the world map of the circulation of modernism, by emphasizing the internal dynamic of the city’s architectural evolution that transcends the colonial-postcolonial divide, and highlighting the evolution of forms revealing a continuity in spite of event-based ruptures in history. The significant presence of modernist buildings with curved corners in Phnom Penh, and their similarities to those of Ho Chi Minh City, suggest that regional circulation also played a crucial role.

Rounded Edges: Modernism and Architectural Dialogue in Ho Chi Minh City

It is widely considered that there is no critical mass of architecture in a homogeneous style in Ho Chi Minh City, in contrast to Hanoi. This essay seeks to establish Ho Chi Minh City’s architectural heritage as a significant one, by arguing that the city does actually possess a critical mass of cohesive, remarkably well-designed buildings in modernist styles. Highlighted here is a unique feature of these modernist buildings: rounded, curved corners as a recurring motif in a dense urban center. The author argues that such buildings, dating from the 1920s through the 1970s, have provided the center of Ho Chi Minh City unique, cohesive, and striking characteristics and that they form one of the great ensembles of modernist architecture anywhere. This essay aims to re-locate the place of Ho Chi Minh City on the world map of the circulation of modernism, by emphasizing the internal dynamic of the city’s architectural evolution that transcends the colonial-postcolonial divide, and highlighting the evolution of forms revealing a continuity in spite of event-based ruptures in history. The significant presence of modernist buildings with curved corners in Phnom Penh, and their similarities to those of Ho Chi Minh City, suggest that regional circulation also played a crucial role.

Relativistic Axions from Collapsing Bose Stars.

The substructures of light bosonic (axionlike) dark matter may condense into compact Bose stars. We study the collapse of critical-mass stars caused by attractive self-interaction of the axionlike particles and find that these processes proceed in an unexpected universal way. First, nonlinear self-similar evolution (called "wave collapse" in condensed matter physics) forces the particles to fall into the star center. Second, interactions in the dense center create an outgoing stream of mildly relativistic particles which carries away an essential part of the star mass. The collapse stops when the star remnant is no longer able to support the self-similar infall feeding the collisions. We shortly discuss possible astrophysical and cosmological implications of these phenomena.

What is the Required Level of Details to Represent the Impact of the Built Environment on Energy Demand?

A full coupling between a CFD code, a thermo-radiative model and a building energy simulation model enables Solene-microclimat software to calculate both building thermal behavior and urban microclimate with the retroaction of buildings on microclimate. However, this full coupling is time consuming and it is legitimate to wonder if it is always necessary to perform such detailed simulations. In the framework of the MERUBBI project, simulations were carried out to answer this question. A set of simulations was designed to explore different kinds of configurations: three cities in France (Nantes, Paris and Strasbourg), three levels of density (from an isolated building to an implementation in the dense city center) and three kinds of buildings (an individual house in Paris, a residential building in Nantes and an office building in Strasbourg). To study the sensitivity of energy demand to the coupling detail, for each thermal flux at the external surfaces of the building, several levels of details were taken into account. For the impact of wind on convection, three modalities were considered: a constant convective heat transfer coefficient, calculated from the wind velocity at 10m; a convective heat transfer coefficient calculated from a vertical wind profile; a convective heat transfer coefficient calculated from the local wind velocity simulated with a CFD code. For the impact of air temperature on convection, two modalities are considered the use of the temperature measured at the nearest meteorological station; a local temperature calculated with the CFD simulation. For the impact of long-wave radiative exchanges, three modalities: the building exchanges with the sky without taking into account the masks of the environment and the long-wave radiative exchanges with the other surfaces; the building exchanges with the sky, taking into account the mask effects but not the exchanges with the surrounding surfaces; long-wave exchanges are taken into account with all kinds of surfaces in function of view factors. For the impact of short-wave radiations, two modalities: only direct and diffuse solar fluxes are taken into account; inter-reflections are considered. The results indicate that if the calculation of air temperature and convective heat transfer coefficient have few impacts in all the cases, the way of calculating long-wave and short wave radioactive fluxes has to be carefully considered, in winter as in summer. More detailed recommendations are given according to the density of the site in which the building will be implemented.

Diurnal, weekly, seasonal, and spatial variabilities in carbon dioxide flux in different urban landscapes in Sakai, Japan

Abstract. To evaluate CO2 emissions in urban areas and their temporal and spatial variability, continuous measurements of CO2 fluxes were conducted using the eddy covariance method at three locations in Sakai, Osaka, Japan. Based on the flux footprint at the measurement sites, CO2 fluxes from the three sites were partitioned into five datasets representing a dense urban center, a moderately urban area, a suburb, an urban park, and a rural area. A distinct biological uptake of CO2 was observed in the suburb, urban park, and rural areas in the daytime, whereas high emissions were observed in the dense and moderate urban areas in the daytime. Weekday CO2 emissions in the dense urban center and suburban area were approximately 50 % greater than emissions during weekends and holidays, but the other landscapes did not exhibit a clear weekly cycle. Seasonal variations in the urban park, rural area, and suburban area were influenced by photosynthetic uptake, exhibiting the lowest daily emissions or even uptake during the summer months. In contrast, the dense and moderately urban areas emitted CO2 in all seasons. CO2 emissions in the urban areas were high in the winter and summer months, and they significantly increased with the increase in air temperature in the summer and the decrease in air temperature in the winter. Irrespective of the land cover type, all urban landscapes measured in this study acted as net annual CO2 sources, with emissions ranging from 0.5 to 4.9 kg C m−2 yr−1. The magnitude of the annual CO2 emissions was negatively correlated with the green fraction; areas with a smaller green fraction had higher annual CO2 emissions. Upscaled flux estimated based on the green fraction indicated that the emissions for the entire city were 3.3 kg C m−2 yr−1, which is equivalent to 0.5 Tg C yr−1 or 1.8 Mt CO2 yr−1, based on the area of the city (149.81 km2). A network of eddy covariance measurements is useful for characterizing the spatial and temporal variations in net CO2 fluxes from urban areas. Multiple methods would be required to evaluate the rationale behind the fluxes and overcome the limitations in the future.

The vertical thickness of Jupiter's Europa gas torus from charged particle measurements

AbstractMeasurements and modeling suggest the presence of a neutral gas torus collocated with the orbit of Jupiter's moon Europa. Here we use data from the CMS instrument that is part of the Energetic Particles Detector (EPD) on board the Galileo spacecraft to characterize the distribution of 130 keV protons. Near the orbit of Europa this distribution has a minimum around 70° in equatorial pitch angle. We reproduce this with a model assuming that the protons are lost via charge exchange with a gas torus. Since the pitch angle characterizes whether the protons remain mostly in the dense center of the torus or continuously bounce through it, we can determine the latitudinal extent of the torus. We find that the full thickness where its density falls to 1/e of its maximum has to be and is closer to ≈1RJ.

Bundled parking and vehicle ownership: Evidence from the American Housing Survey

This article estimates the effect of bundled residential parking—parking whose price is included in the rent or purchase price of housing—on household vehicle ownership. Using data from the American Housing Survey, I show that the odds of households with bundled parking being vehicle-free are 50–75 percent lower than the odds of households without bundled parking, while households in dense center cities near transit are twice as likely to be without vehicles if they lack bundled parking. I also find substantial, though less stable, evidence that bundled parking encourages driving among commuters who have vehicles. These results are robust to a wide variety of demographic and land-use controls and to controls for residential self-selection. Examining self-selection shows that housing without bundled parking is sufficiently scarce and geographically concentrated that people who search for it may not find it. Four metropolitan areas, which hold 11 percent of U.S. housing units, hold more than 40 percent of its housing without bundled parking. Overall, the results suggest that when cities require parking with residential development, they increase vehicle ownership and use.

Star formation and black hole accretion activity in rich local clusters of galaxies

We present a study of the star formation and central black hole accretion activity of the galaxies hosted in the two nearby (z$\sim$0.2) rich galaxy clusters Abell 983 and 1731. Aims: We are able to quantify both the obscured and unobscured star formation rates, as well as the presence of active galactic nuclei (AGN) as a function of the environment in which the galaxy is located. Methods: We targeted the clusters with unprecedented deep infrared Spitzer observations (0.2 mJy @ 24 micron), near-IR Palomar imaging and optical WIYN spectroscopy. The extent of our observations ($\sim$ 3 virial radii) covers the vast range of possible environments, from the very dense cluster centre to the very rarefied cluster outskirts and accretion regions. Results: The star forming members of the two clusters present star formation rates comparable with those measured in coeval field galaxies. The analysis of the spatial arrangement of the spectroscopically confirmed members reveals an elongated distribution for A1731 with respect to the more uniform distribution of A983. The emerging picture is compatible with A983 being a fully evolved cluster, in contrast with the still actively accreting A1731. Conclusions: The analysis of the specific star formation rate reveals evidence of on-going galaxy pre-processing along A1731's filament-like structure. Furthermore, the decrease in the number of star forming galaxies and AGN towards the cluster cores suggests that the cluster environment is accelerating the ageing process of galaxies and blocking further accretion of the cold gas that fuels both star formation and black hole accretion activity.

Residential mobility in the Barcelona Metropolitan Region during the present economic crisis

Abstract These last few years, the Barcelona metropolitan region has had two main distinct residential mobility flows, each defining their own spatial patterns. On the one hand, there has been one made by Spanish people who, since the late 1970s, have been moving from the dense metropolitan centre towards its periphery where they can find medium-sized towns and small municipalities to which they are attracted. On the other hand, since the early twenty-first century there has also been that of foreigners moving from Barcelona to the neighbouring central cities. This article analyses recent intensity and spatial pattern changes due to the economic and housing market crises. Focusing on the 2009–2012 period, it compares two previous decades from 1988–2008. Our main hypothesis is that in recent years the flows have slightly diminished but they have had a stronger geographic impact as spatial trends existing before the economic crisis have blurred.