755 research outputs found
Upgrading Marine Ecosystem Restoration Using Ecological-Social Concepts
Conservation and environmental management are principal countermeasures to the degradation of marine ecosystems and their services. However, in many cases, current practices are insufficient to reverse ecosystem declines. We suggest that restoration ecology, the science underlying the concepts and tools needed to restore ecosystems, must be recognized as an integral element for marine conservation and environmental management. Marine restoration ecology is a young scientific discipline, often with gaps between its application and the supporting science. Bridging these gaps is essential to using restoration as an effective management tool and reversing the decline of marine ecosystems and their services. Ecological restoration should address objectives that include improved ecosystem services, and it therefore should encompass social ecological elements rather than focusing solely on ecological parameters. We recommend using existing management frameworks to identify clear restoration targets, to apply quantitative tools for assessment, and to make the re-establishment of ecosystem services a criterion for success
Challenges for Restoration of Coastal Marine Ecosystems in the Anthropocene
Coastal marine ecosystems provide critical goods and services to humanity but many are experiencing rapid degradation. The need for effective restoration tools capable of promoting large-scale recovery of coastal ecosystems in the face of intensifying climatic stress has never been greater. We identify four major challenges for more effective implementation of coastal marine ecosystem restoration (MER): (1) development of effective, scalable restoration methods, (2) incorporation of innovative tools that promote climate adaptation, (3) integration of social and ecological restoration priorities, and (4) promotion of the perception and use of coastal MER as a scientifically credible management approach. Tackling these challenges should improve restoration success rates, heighten their recognition, and accelerate investment in and promotion of coastal MER. To reverse the accelerating decline of marine ecosystems, we discuss potential directions for meeting these challenges by applying coastal MER tools that are science-based and actionable. For coastal restoration to have a global impact, it must incorporate social science, technological and conceptual advances, and plan for future climate scenarios
MultiSector Dynamics: Scientific Challenges and a Research Vision for 2030, A Community of Practice Supported by the United States Department of Energy\u27s Office of Science
Agriculture in Taiwan and South Korea: the minimalist state?
SUMMARY The state has intervened heavily in the agricultural economies of Taiwan and South Korea, both by direct administrative means and by establishing price relativities very different from those set by market forces. Although state action has not always been effective or efficient, it has played a major role in making agriculture serve the objective of rapid industrial growth. The forms and consequences of state intervention have changed over time in response to the political and economic pressures arising from structural economic change. The state has been obliged to be interventionist in order to try to maintain the political order on which continual reinvestment and thus continued growth depend. RESUMEN Agricultura en Taiwán y Corea del Sur: estado minimalista? El estado ha intervenido fuertemente en la economía agrícola en ambos países, tanto por medios directamente administrativos, como por el establecimento de precios relativos muy diferentes de aquellos derivados de la acción de las fuerzas del mercado. Aunque no siempre la acción estatal ha sido efectiva o eficiente, ha jugado un rol principal para que la agricultura sirva los objetivos de un rápido crecimiento industrial. Las formas y consecuencias de la intervención estatal han cambiado a través del tiempo, como respuesta a las presiones económicas derivadas del cambio en la estructura económica. El estado se ha visto obligado a ser intervencionista para tratar de mantener el orden politico del cual depende la continua reínversíón y, en consecuencia, el crecimiento persistente. RESUMES L'agriculture à Taiwan et en Corée du Sud: l'état minimaliste? L'état a intervenu de façon très importante dans les économies agricoles de Taiwan et de la Corée du Sud, par des moyens administratifs directs et en établissant une relativité des prix très différente de celle établie par les forces de marché. Quoique l'action de l'état n'ait pas toujours été effective ou efficace, elle a joué un rôle de grande importance en se servant de l'agriculture pour aider une croissance industrielle rapide. Les formes et les conséquences de l'intervention de l'état ont changé au cours des temps en fonction des pressions politiques et économiques provenant du changement de la structure économique. L'état a été obligé d'être interventionniste de façon à essayer de maintenir l'ordre politique duquel dépendent le rèinvestissement continu et donc la croissance continue
Circuit Quantum Electrodynamics with a Spin Qubit
Circuit quantum electrodynamics allows spatially separated superconducting
qubits to interact via a "quantum bus", enabling two-qubit entanglement and the
implementation of simple quantum algorithms. We combine the circuit quantum
electrodynamics architecture with spin qubits by coupling an InAs nanowire
double quantum dot to a superconducting cavity. We drive single spin rotations
using electric dipole spin resonance and demonstrate that photons trapped in
the cavity are sensitive to single spin dynamics. The hybrid quantum system
allows measurements of the spin lifetime and the observation of coherent spin
rotations. Our results demonstrate that a spin-cavity coupling strength of 1
MHz is feasible.Comment: Related papers at http://pettagroup.princeton.edu
Effectiveness of Transmitted Drug Resistance Testing Before Initiation of Antiretroviral Therapy in HIV-Positive Individuals
BACKGROUND
For people living with HIV, major guidelines in high-income countries recommend testing for transmitted drug resistance (TDR) to guide the choice of first-line antiretroviral therapy (ART). However, individuals who fail a first-line regimen can now be switched to one of several effective regimens. Therefore, the virological and clinical benefit of TDR testing needs to be evaluated.
METHODS
We included individuals from the HIV-CAUSAL Collaboration who enrolled <6 months of HIV diagnosis between 2006 and 2015, were ART-naive, and had measured CD4 count and HIV-RNA. Follow-up started at the date when all inclusion criteria were first met (baseline). We compared 2 strategies: (1) TDR testing within 3 months of baseline versus (2) no TDR testing. We used inverse probability weighting to estimate the 5-year proportion and hazard ratios (HRs) of virological suppression (confirmed HIV-RNA <50 copies/mL), and of AIDS or death under both strategies.
RESULTS
Of 25,672 eligible individuals (82% males, 52% diagnosed in 2010 or later), 17,189 (67%) were tested for TDR within 3 months of baseline. Of these, 6% had intermediate- or high-level TDR to any antiretroviral drug. The estimated 5-year proportion virologically suppressed was 77% under TDR testing and 74% under no TDR testing; HR 1.06 (95% confidence interval: 1.03 to 1.19). The estimated 5-year risk of AIDS or death was 6% under both strategies; HR 1.03 (95% confidence interval: 0.95 to 1.12).
CONCLUSIONS
TDR prevalence was low. Although TDR testing improved virological response, we found no evidence that it reduced the incidence of AIDS or death in first 5 years after diagnosis
Laplaciens de graphes infinis I Graphes m\'etriquement complets
We introduce the weighted graph Laplacian and the notion of Schr\"odinger
operator on a locally finite weighted graph . Concerning essential
self-adjointness, we extend Wojciechowski's and Dodziuk's results for graphs
with vertex constant weight. The main result in this work states that on any
metrically complete weighted graph with bounded degree, the Laplacian is
essentially self-adjoint and the same holds for the Schr\"odinger operator
provided the associated quadratic form is bounded from below. We construct for
the proof a strictly positive and harmonic function which allows us to write
any Schr\"odinger operator as a weighted graph Laplacian modulo a unitary
transform
The Formation of the First Massive Black Holes
Supermassive black holes (SMBHs) are common in local galactic nuclei, and
SMBHs as massive as several billion solar masses already exist at redshift z=6.
These earliest SMBHs may grow by the combination of radiation-pressure-limited
accretion and mergers of stellar-mass seed BHs, left behind by the first
generation of metal-free stars, or may be formed by more rapid direct collapse
of gas in rare special environments where dense gas can accumulate without
first fragmenting into stars. This chapter offers a review of these two
competing scenarios, as well as some more exotic alternative ideas. It also
briefly discusses how the different models may be distinguished in the future
by observations with JWST, (e)LISA and other instruments.Comment: 47 pages with 306 references; this review is a chapter in "The First
Galaxies - Theoretical Predictions and Observational Clues", Springer
Astrophysics and Space Science Library, Eds. T. Wiklind, V. Bromm & B.
Mobasher, in pres
Genome Analysis of Cytochrome P450s and Their Expression Profiles in Insecticide Resistant Mosquitoes, Culex quinquefasciatus
Here we report a study of the 204 P450 genes in the whole genome sequence of larvae and adult Culex quinquefasciatus mosquitoes. The expression profiles of the P450 genes were compared for susceptible (S-Lab) and resistant mosquito populations, two different field populations of mosquitoes (HAmCq and MAmCq), and field parental mosquitoes (HAmCq G0 and MAmCqG0) and their permethrin selected offspring (HAmCq G8 and MAmCqG6). While the majority of the P450 genes were expressed at a similar level between the field parental strains and their permethrin selected offspring, an up- or down-regulation feature in the P450 gene expression was observed following permethrin selection. Compared to their parental strains and the susceptible S-Lab strain, HAmCqG8 and MAmCqG6 were found to up-regulate 11 and 6% of total P450 genes in larvae and 7 and 4% in adults, respectively, while 5 and 11% were down-regulated in larvae and 4 and 2% in adults. Although the majority of these up- and down-regulated P450 genes appeared to be developmentally controlled, a few were either up- or down-regulated in both the larvae and adult stages. Interestingly, a different gene set was found to be up- or down-regulated in the HAmCqG8 and MAmCqG6 mosquito populations in response to insecticide selection. Several genes were identified as being up- or down-regulated in either the larvae or adults for both HAmCqG8 and MAmCqG6; of these, CYP6AA7 and CYP4C52v1 were up-regulated and CYP6BY3 was down-regulated across the life stages and populations of mosquitoes, suggesting a link with the permethrin selection in these mosquitoes. Taken together, the findings from this study indicate that not only are multiple P450 genes involved in insecticide resistance but up- or down-regulation of P450 genes may also be co-responsible for detoxification of insecticides, insecticide selection, and the homeostatic response of mosquitoes to changes in cellular environment
Statistics of extreme objects in the Juropa Hubble Volume simulation
We present the first results from the JUropa huBbLE volumE (Jubilee) project,
based a large N-body, dark matter-only cosmological simulation with a volume of
, containing 6000 particles, performed within
the concordance CDM cosmological model. The simulation volume is
sufficient to probe extremely large length scales in the universe, whilst at
the same time the particle count is high enough so that dark matter haloes down
to can be resolved. At we
identify over 400 million haloes. The cluster mass function is derived using
three different halofinders and compared to fitting functions in the
literature. The distribution of clusters of maximal mass across redshifts
agrees well with predicted masses of extreme objects, and we explicitly confirm
that the Poisson distribution is very good at describing the distribution of
rare clusters. The Poisson distribution also matches well the level to which
cosmic variance can be expected to affect number counts of high mass clusters.
We find that objects like the Bullet cluster exist in the far-tail of the
distribution of mergers in terms of relative collisional speed. We also derive
the number counts of voids in the simulation box for , and .Comment: Version 2. 12 pages, 9 figures. Accepted by MNRA
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