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Anti-Carbonism or Carbon Exceptionalism: A Discursive Project of Low-Carbon City in Shenzhen, China
As the role of cities in addressing climate change has been increasingly recognized over the past two decades, the idea of a low-carbon city becomes a dominant framework to organize urban governance and envision a sustainable urban future. It also becomes a development discourse in the less developed world to guide the ongoing urbanization process.
Chinaâs efforts toward building low-carbon cities have been inspiring at first and then obscured by the halt or total failure of famous mega-projects, leading to a conclusion that Chinese low-carbon cities compose merely a strategy of green branding for promoting local economy. This conclusion, however, largely neglects the profound implications of the decarbonization discourse for the dynamics between the central and local governments, which together determine the rules and resources for development practices. The conclusion also hinders the progressive potentials of the decarbonization discourse in terms of introducing new values and norms to urban governance.
This dissertation approaches âlow-carbon citiesâ as a part of the decarbonization discourse and employs a discourse-institutional analysis to investigate the relationships between discourse, institutional arrangement, and socio-political resources for development activities. Through an examination of the Shenzhen International Low-Carbon City (SILCC), the dissertation answers three questions: (1) How does the framework of a low-carbon city affect a specific urban development project? (2) What is the role of the state (local/national) in promoting low-carbon development? and (3) What is the influence of the decarbonization discourse on institutions and norms of urban governance? Evidence was gathered during 2014-2017 from three fieldtrips, 39 interviews and the review of government documents and other archives.
The dissertation highlights how different levels of government became entangled in developing a local area and how, in doing so, the proponents continuously searched for ways of âpositioningâ their initiative in discourses that would attract higher level government support, maintain local coalitions, and entice international attention and investment. In this regard, low-carbon cities are a state discursive project. Rather than an established material goal, a low-carbon city is an evolving process in which the decarbonization discourse introduces a new set of values, metrics and governing logics into development practices and redefines the legitimacy and accountability of urban development. Furthermore, the local state leverages the interpretive flexibility within the decarbonization discourse through strategies including carbon labeling, weak carbonization, and carbon exceptionalism. Consequently, the state takes a strategic position to reconfigure the state-society as well as the environment-economy relationships
Single vibronic level emission spectroscopic studies of the ground state energy levels and molecular structures of jet-cooled HGeBr, DGeBr, HGeI, and DGeI
Single vibronic level dispersed fluorescence spectra of jet-cooled HGeBr, DGeBr, HGeI, and DGeI have been obtained by laser excitation of selected bands of the AÌ Aâł1-XÌ AâČ1 electronic transition. The measured ground state vibrational intervals were assigned and fitted to anharmonicity expressions, which allowed the harmonic frequencies to be determined for both isotopomers. In some cases, lack of a suitable range of emission data necessitated that some of the anharmonicity constants and vibrational frequencies be estimated from those of HGeClâDGeCl and the corresponding silylenes (HSiX). Harmonic force fields were obtained for both molecules, although only four of the six force constants could be determined. The ground state effective rotational constants and force field data were combined to calculate average (rz) and approximate equilibrium (rze) structures. For HGeBr rze(GeH)=1.593(9)Ă
, rze(GeBr)=2.325(21)Ă
, and the bond angle was fixed at our CCSD(T)/aug-cc-pVTZ ab initio value of 93.6°. For HGeI we obtained rze(GeH)=1.589(1)Ă
, rze(GeI)=2.525(5)Ă
, and bond angle=93.2°. Franck-Condon simulations of the emission spectra using ab initio Cartesian displacement coordinates reproduce the observed intensity distributions satisfactorily. The trends in structural parameters in the halogermylenes and halosilylenes can be readily understood based on the electronegativity of the halogen substituent. ACKNOWLEDGMENT
The SUPERCOLD-CGM survey: \\ I. Probing the extended CO(4-3) Emission of the Circumglactic medium in a sample of 10 Enormous Ly Nebulae at
To understand how massive galaxies at high- co-evolve with enormous
reservoirs of halo gas, it is essential to study the coldest phase of the
circum-galactic medium (CGM), which directly relates to stellar growth. The
SUPERCOLD-CGM survey is the first statistical survey of cold molecular gas on
CGM scales. We present ALMA+ACA observations of CO(4-3) and continuum emission
from 10 Enormous Ly Nebula (ELANe) around ultraluminous type-I QSOs at
. We detect CO(4-3) in 100 of our targets, with 60 showing
extended CO on scales of 15100 kpc. Q1228+3128 reveals the most extended
CO(4-3) reservoir of 100 kpc and is the only radio-loud target in our
sample. The CO reservoir is located along the radio axis, which could indicate
a link between the inner radio-jet and cold halo gas. For the other five
radio-quiet ELANe, four of them show extended CO(4-3) predominantly in the
direction of their companions. These extended CO(4-3) reservoirs identify
enrichment of the CGM, and may potentially contribute to widespread star
formation. However, there is no evidence from CO(4-3) for diffuse molecular gas
spread across the full extent of the Ly nebulae. One target in our
sample (Q0107) shows significant evidence for a massive CO disk associated with
the QSO. Moreover, 70 of our QSO fields contain at least one CO companion,
two of which reveal extended CO emission outside the ELANe. Our results provide
insight into roles of both the cold CGM and companions in driving the early
evolution of massive galaxies.Comment: Accepted for publication in ApJ. 27 pages, 16 figure
The Mass-Metallicity Relation of Dwarf Galaxies at the Cosmic Noon in the JWST Era
We present the mass-metallicity relation (MZR) at in the stellar mass
range of using 55 dwarf galaxies in
the Abell 2744 and SMACS J0723-3732 galaxy cluster fields. These dwarf galaxies
are identified and confirmed by deep JWST/NIRISS imaging and slitless grism
spectroscopic observations. Taking advantage of the gravitational lensing
effect, we extend the previous MZR relation at to a much lower mass
regime by more than 2.5 orders of magnitude compared with previous studies. We
find that the MZR has a shallower slope at the low-mass end
() compared to that at the high-mass end
(), with a slope turnover point at around the stellar
mass of . This implies that dominating feedback processes in
dwarf galaxies may be different from that in galaxies with higher mass. From
to , the metallicity of the dwarf galaxies is enhanced by
dex for a given stellar mass, consistent with the mild evolution
found in galaxies with higher mass. Further, we confirm the existence of a 3D
relation between the gas-phase metallicity, stellar mass, and star formation
rate, i.e., fundamental metallicity relation (FMR), in dwarf galaxies at
. Our derived FMR, which has no significant redshift evolution, can be
used as a benchmark to understand the origin of the anti-correlation between
SFR and metallicity of dwarf galaxies in the high-redshift Universe.Comment: 16 pages, 4 figures, 1 table, submitted to AAS Journal; welcome
comment
Metal-Enriched Neutral Gas Reservoir around a Strongly-lensed, Low-mass Galaxy at Identified by JWST/NIRISS and VLT/MUSE
Direct observations of low-mass, low-metallicity galaxies at
provide an indispensable opportunity for detailed inspection of the ionization
radiation, gas flow, and metal enrichment in sources similar to those that
reionized the Universe. Combining the James Webb Space Telescope (JWST),
VLT/MUSE, and ALMA, we present detailed observations of a strongly lensed,
low-mass ( ) galaxy at (also see
Vanzella et al. 2022). We identify strong narrow nebular emission, including
CIV , HeII , OIII]
, [NeIII] , [OII] , and
Balmer series of Hydrogen from this galaxy, indicating a metal-poor HII region
() powered by massive stars. Further, we detect a
metal-enriched damped Ly system (DLA) associated with the galaxy with
the HI column density of cm. The
metallicity of the associated DLA may reach the super solar metallicity
(). Moreover, thanks to JWST and gravitational lensing, we
present the resolved UV slope () map at the spatial resolution of
pc at , with steep UV slopes reaching
around three star-forming clumps. Combining with low-redshift analogs, our
observations suggest that low-mass, low-metallicity galaxies, which dominate
reionization, could be surrounded by a high covering fraction of the
metal-enriched, neutral-gaseous clouds. This implies that the metal enrichment
of low-mass galaxies is highly efficient, and further support that in low-mass
galaxies, only a small fraction of ionizing radiation can escape through the
interstellar or circumgalactic channels with low column-density neutral gas.Comment: 4 pages, 1 table; submitted to the ApJL; welcome comment
Searching for C ii Emission from the First Sample of z ⌠6 O i Absorption-associated Galaxies with the Atacama Large Millimeter/submillimeter Array
We report the first statistical analyses of [C ii ] and dust continuum observations in six strong O i absorber fields at the end of the reionization epoch obtained by the Atacama Large Millimeter/submillimeter Array (ALMA). Combined with one [C ii ] emitter reported in Wu et al., we detect one O i -associated [C ii ] emitter in six fields. At redshifts of O i absorbers in nondetection fields, no emitters are brighter than our detection limit within impact parameters of 50 kpc and velocity offsets between ±200 km s ^â1 . The averaged [C ii ]-detection upper limit is 50 kpc) and having larger outflow velocities within ±600 km s ^â1 . If these detections are confirmed in the future, then the mechanism of pushing metals at larger distances with higher velocities needs to be further explored from the theoretical side
Inhibition of T Helper Cell Differentiation by Tacrolimus or Sirolimus Results in Reduced B-Cell Activation: Effects on T Follicular Helper Cells
The effect of immunosuppressive drugs on the generation of T follicular helper (Tfh) cells, specialized in supporting B-cell differentiation, is largely unknown. We examined whether the calcineurin inhibitor tacrolimus (TAC) and the mammalian target of rapamycin (mtor) inhibitor sirolimus (SRL) inhibit Tfh cell differentiation, and affect subsequent B-cell functions. Isolated naive T cells were polarized into Tfh-like cells in the presence of TAC or SRL. To demonstrate their functionality, we co-cultured these cells with isolated B cells in the presence of alloantigen and studied the activation and differentiation of these B cells. Tfh-like cells were defined as CD4+CXCR5+ T cells, expressing immunoinhibitory programmed death protein 1 (pd1) and inducible T-cell costimulator (icos). We found that TAC and SRL significantly inhibited Tfh-like cell differentiation. Therapeutic concentrations of TAC and SRL reduced the percentage of pd1+ and icos+ Tfh cells compared to controls. In addition, T cells grown in the presence of TAC or SRL expressed less IL-21 and provided less B-cell help. TAC and SRL both inhibited Tfh-dependent alloantigen-activated B-cell proliferation and differentiation into plasma cells and transitional B cells. In conclusion, TAC and SRL inhibited the differentiation of naive T cells into functional Tfh-like cells, a finding that can be extrapolated to immunosuppressive regimens in transplant patients
A SPectroscopic Survey of Biased Halos in the Reionization Era (ASPIRE): JWST Reveals a Filamentary Structure around a z = 6.61 Quasar
© 2023. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/We present the first results from the JWST program A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE). This program represents an imaging and spectroscopic survey of 25 reionization-era quasars and their environments by utilizing the unprecedented capabilities of NIRCam Wide Field Slitless Spectroscopy (WFSS) mode. ASPIRE will deliver the largest ( âŒ280arcmin2 ) galaxy redshift survey at 3â4 ÎŒm among JWST Cycle 1 programs and provide extensive legacy values for studying the formation of the earliest supermassive black holes, the assembly of galaxies, early metal enrichment, and cosmic reionization. In this first ASPIRE paper, we report the discovery of a filamentary structure traced by the luminous quasar J0305â3150 and 10 [O iii] emitters at z = 6.6. This structure has a 3D galaxy overdensity of ÎŽ gal = 12.6 over 637 cMpc3, one of the most overdense structures known in the early universe, and could eventually evolve into a massive galaxy cluster. Together with existing VLT/MUSE and ALMA observations of this field, our JWST observations reveal that J0305â3150 traces a complex environment where both UV-bright and dusty galaxies are present and indicate that the early evolution of galaxies around the quasar is not simultaneous. In addition, we discovered 31 [O iii] emitters in this field at other redshifts, 5.3 < z < 6.7, with half of them situated at z ⌠5.4 and 6.2. This indicates that star-forming galaxies, such as [O iii] emitters, are generally clustered at high redshifts. These discoveries demonstrate the unparalleled redshift survey capabilities of NIRCam WFSS and the potential of the full ASPIRE survey data set.Peer reviewe
A SPectroscopic Survey of Biased Halos in the Reionization Era (ASPIRE): A First Look at the Rest-frame Optical Spectra of z > 6.5 Quasars Using JWST
© 2023. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the Creative Commons Attribution License, to view a copy of the license, see: https://creativecommons.org/licenses/by/4.0/Studies of rest-frame optical emission in quasars at z > 6 have historically been limited by the wavelengths accessible by ground-based telescopes. The James Webb Space Telescope (JWST) now offers the opportunity to probe this emission deep into the reionization epoch. We report the observations of eight quasars at z > 6.5 using the JWST/NIRCam Wide Field Slitless Spectroscopy as a part of the âA SPectroscopic survey of biased halos In the Reionization Era (ASPIRE)â program. Our JWST spectra cover the quasarsâ emission between rest frame âŒ4100 and 5100 Ă
. The profiles of these quasarsâ broad HÎČ emission lines span a full width at half maximum from 3000 to 6000 km sâ1. The HÎČ-based virial black hole (BH) masses, ranging from 0.6 to 2.1 billion solar masses, are generally consistent with their Mg ii-based BH masses. The new measurements based on the more reliable HÎČ tracer thus confirm the existence of a billion solar-mass BHs in the reionization epoch. In the observed [O iii] λ λ 4960,5008 doublets of these luminous quasars, broad components are more common than narrow core components (†1200 km sâ1), and only one quasar shows stronger narrow components than broad. Two quasars exhibit significantly broad and blueshifted [O iii] emission, thought to trace galactic-scale outflows, with median velocities of â610 and â1430 km sâ1 relative to the [C ii] 158 ÎŒm line. All eight quasars show strong optical Fe ii emission and follow the eigenvector 1 relations defined by low-redshift quasars. The entire ASPIRE program will eventually cover 25 quasars and provide a statistical sample for the studies of the BHs and quasar spectral properties.Peer reviewe
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