949 research outputs found
Valuing the biodiversity gains from protecting native plant communities from bitou bush (Chrysanthemoides monilifera subsp rotundata (DC.) T.Norl.) in New South Wales: application of the defensive expenditure method
Valuation of the gains from protection of biodiversity is difficult because the services that provide the benefits do not normally pass through markets where prices can form. But the services sometimes pass through markets where consumers or producers behave in a market-oriented manner, and so the values implicit in this behaviour can be identified and derived. Estimates of the benefits of biodiversity protection are derived from the costs of protecting native plant communities from a major weed in Australia, by following this approach. In 1999, invasion of coastal areas of New South Wales by bitou bush (Chrysanthemoides monilifera subsp. rotundata (DC.) T. Norl.) was listed as a key process threatening native plants under the NSW Threatened Species Conservation Act 1995. In accordance with the Act, the Department of Environment and Climate Change prepared a Threat Abatement Plan (TAP) to reduce the impacts of bitou bush on biodiversity at each threatened site. The costs of protecting sites vary closely with the number of priority native species and communities at each site. Following standard economic assumptions about market transactions, these costs are interpreted to provide values the benefits of protecting extra species, communities, and sites. Key words: Bitou bush, Chrysanthemoides monilifera, threat abatement plan, valuation of biodiversity, benefit-cost analysis, weed control, defensive-expenditure method.Bitou bush, Chrysanthemoides monilifera, threat abatement plan, valuation of biodiversity, benefit-cost analysis, weed control, defensive-expenditure method, Demand and Price Analysis, Environmental Economics and Policy,
Semi- and fully synthetic carbohydrate vaccines against pathogenic bacteria : recent developments
The importance of vaccine-induced protection was repeatedly demonstrated over the last three decades and emphasized during the recent COVID-19 pandemic as the safest and most effective way of preventing infectious diseases. Vaccines have controlled, and in some cases, eradicated global viral and bacterial infections with high efficiency and at a relatively low cost. Carbohydrates form the capsular sugar coat that surrounds the outer surface of human pathogenic bacteria. Specific surface-exposed bacterial carbohydrates serve as potent vaccine targets that broadened our toolbox against bacterial infections. Since first approved for commercial use, antibacterial carbohydrate-based vaccines mostly rely on inherently complex and heterogenous naturally derived polysaccharides, challenging to obtain in a pure, safe, and cost-effective manner. The introduction of synthetic fragments identical with bacterial capsular polysaccharides provided well-defined and homogenous structures that resolved many challenges of purified polysaccharides. The success of semisynthetic glycoconjugate vaccines against bacterial infections, now in different phases of clinical trials, opened up new possibilities and encouraged further development towards fully synthetic antibacterial vaccine solutions. In this mini-review, we describe the recent achievements in semi- and fully synthetic carbohydrate vaccines against a range of human pathogenic bacteria, focusing on preclinical and clinical studies
The Complexity of Routing with Few Collisions
We study the computational complexity of routing multiple objects through a
network in such a way that only few collisions occur: Given a graph with
two distinct terminal vertices and two positive integers and , the
question is whether one can connect the terminals by at least routes (e.g.
paths) such that at most edges are time-wise shared among them. We study
three types of routes: traverse each vertex at most once (paths), each edge at
most once (trails), or no such restrictions (walks). We prove that for paths
and trails the problem is NP-complete on undirected and directed graphs even if
is constant or the maximum vertex degree in the input graph is constant.
For walks, however, it is solvable in polynomial time on undirected graphs for
arbitrary and on directed graphs if is constant. We additionally study
for all route types a variant of the problem where the maximum length of a
route is restricted by some given upper bound. We prove that this
length-restricted variant has the same complexity classification with respect
to paths and trails, but for walks it becomes NP-complete on undirected graphs
Filling-induced Mott transition and pseudogap physics in the triangular lattice Hubbard model
It has been reported that upon doping a Mott insulator, there can be a
crossover to a strongly correlated metallic phase followed by a first-order
transition to another thermodynamically stable metallic phase. We call this
first-order metal-metal transition the Sordi transition. To show theoretically
that this transition is observable, it is important to provide calculations in
situations where magnetic phase transitions do not hide the Sordi transition.
It is also important to show that it can be found on large clusters and with
different approaches. Here, we use the dynamical cluster approximation to
reveal the Sordi transition on a triangular lattice at finite temperature in
situations where there is no long-range magnetic correlations. This is relevant
for experiments on candidate spin-liquid organics. We also show that the
metallic phase closest to the insulator is a distinct pseudogap phase that
occurs because of strong interactions and short-range correlations
Phase Transition and Strong Predictability
The statistical mechanical interpretation of algorithmic information theory
(AIT, for short) was introduced and developed in our former work [K. Tadaki,
Local Proceedings of CiE 2008, pp.425-434, 2008], where we introduced the
notion of thermodynamic quantities into AIT. These quantities are real
functions of temperature T>0. The values of all the thermodynamic quantities
diverge when T exceeds 1. This phenomenon corresponds to phase transition in
statistical mechanics. In this paper we introduce the notion of strong
predictability for an infinite binary sequence and then apply it to the
partition function Z(T), which is one of the thermodynamic quantities in AIT.
We then reveal a new computational aspect of the phase transition in AIT by
showing the critical difference of the behavior of Z(T) between T=1 and T<1 in
terms of the strong predictability for the base-two expansion of Z(T).Comment: 5 pages, LaTeX2e, no figure
A note on the differences of computably enumerable reals
We show that given any non-computable left-c.e. real α there exists a left-c.e. real β such that α≠β+γ for all left-c.e. reals and all right-c.e. reals γ. The proof is non-uniform, the dichotomy being whether the given real α is Martin-Loef random or not. It follows that given any universal machine U, there is another universal machine V such that the halting probability of U is not a translation of the halting probability of V by a left-c.e. real. We do not know if there is a uniform proof of this fact
Mott transition, Widom line and pseudogap in the half-filled triangular lattice Hubbard model
The Mott transition is observed experimentally in materials that are
magnetically frustrated so that long-range order does not hide the Mott
transition at finite temperature. The Hubbard model on the triangular lattice
at half-filling is a paradigmatic model to study the interplay of interactions
and frustration on the normal-state phase diagram. We use the dynamical cluster
approximation with continuous time auxiliary field quantum Monte Carlo to solve
this model for 1, 4, 6, 12, and 16 site clusters with detailed analysis
performed for the 6 site cluster. We show that a) for every cluster there is an
inflection point in the double occupancy as a function of interaction, defining
a Widom line that extends above the critical point of the first-order Mott
transition; b) the presence of this line and the cluster size dependence argue
for the observability of the Mott transition at finite temperature in the
thermodynamic limit; c) the loss of spectral weight in the metal to Mott
insulator transition as a function of temperature and for strong interactions
is momentum dependent, the hallmark of a pseudogap. That pseudogap spans a
large region of the phase diagram near the Mott transition.Comment: Open source version of the published paper. 16 pages, 8 figures,
LaTe
Exoplanet science with the LBTI: instrument status and plans
The Large Binocular Telescope Interferometer (LBTI) is a strategic instrument
of the LBT designed for high-sensitivity, high-contrast, and high-resolution
infrared (1.5-13 m) imaging of nearby planetary systems. To carry out a
wide range of high-spatial resolution observations, it can combine the two
AO-corrected 8.4-m apertures of the LBT in various ways including direct
(non-interferometric) imaging, coronagraphy (APP and AGPM), Fizeau imaging,
non-redundant aperture masking, and nulling interferometry. It also has
broadband, narrowband, and spectrally dispersed capabilities. In this paper, we
review the performance of these modes in terms of exoplanet science
capabilities and describe recent instrumental milestones such as first-light
Fizeau images (with the angular resolution of an equivalent 22.8-m telescope)
and deep interferometric nulling observations.Comment: 12 pages, 6 figures, Proc. SPI
Simultaneous Water Vapor and Dry Air Optical Path Length Measurements and Compensation with the Large Binocular Telescope Interferometer
The Large Binocular Telescope Interferometer uses a near-infrared camera to
measure the optical path length variations between the two AO-corrected
apertures and provide high-angular resolution observations for all its science
channels (1.5-13 m). There is however a wavelength dependent component to
the atmospheric turbulence, which can introduce optical path length errors when
observing at a wavelength different from that of the fringe sensing camera.
Water vapor in particular is highly dispersive and its effect must be taken
into account for high-precision infrared interferometric observations as
described previously for VLTI/MIDI or the Keck Interferometer Nuller. In this
paper, we describe the new sensing approach that has been developed at the LBT
to measure and monitor the optical path length fluctuations due to dry air and
water vapor separately. After reviewing the current performance of the system
for dry air seeing compensation, we present simultaneous H-, K-, and N-band
observations that illustrate the feasibility of our feedforward approach to
stabilize the path length fluctuations seen by the LBTI nuller.Comment: SPIE conference proceeding
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