261 research outputs found
Spatial Monopoly Pricing in a Stochastic Environment
This paper reexamines the welfare implications of three pricing regimes (mill, uniform and discriminatory) for a monopoly in a stochastic environment. It con-siders a risk-averse monopolist faces two markets with stochastic and linear demands. The monopolist is assumed to commit to an irreversible price in each market before the uncertainty is resolved. Several unconventional results are shown to be triggered by the presence of demand uncertainty. The reason for the reversal of orthodox intuition is the asymmetry in the risk chacteristics of the markets and the willingness of the monopolist to trade increased level of expected prots for reduced risk.spatial pricing, monopoly, demand uncertainty
Spatial Economic Theory of Pollution Control under Stochastic Emissions
This paper examines the eectiveness of environmental policies in curtailing pollution of a rm which is operating in a space economy under stochastic emissions. We consider a general n-input planar space production-location model, in which the output is produced jointly with the byproduct pollution. Although production is nonstochastic, the resulting pollution emission is assumed to have a random component, and the polluting rm must make its production and location decisions before the uncertainty is resolved. We provide some propositions concerning the comparative statics of the polluting rm's location choices, urban pollution concentration, and the relative impact of regulation via emission taxes to that of emission standards.location theory, pollution control, emission uncertainty
The effect of mechanical grinding on the mesoporosity of steam-activated palm kernel shell activated carbons
Background: Palm kernel shell activated carbon (OPSA) produced by steam gasification at high temperatures generally results in high surface areas of 1146 to 1600 m2 g−1, attributed to the high volume of micropores (0.43 to 0.56 cm3 g−1). The mesoporosity of naturally occurring activated carbons is observed to increase with decreasing particle size. Mechanical grinding was therefore performed to investigate its effect on the mesoporosity and microporosity of OPSA. Results: Mechanical grinding had a strong effect on mesopore volume and average pore diameter, with an increase in mesopore volume from 47 to 66% as particle size decreases. Interestingly, no significant effect on the micropore fraction was observed in ground OPSA particles. Conclusions: The mechanically ground OPSA particles possessed dual adsorption capabilities due to the high microporosity and moderate mesoporosity contained in the structures. This results in interesting porosity behaviour of palm kernel shell activated carbons and the potential to provide materials of distinct sorption capacities with minimal treatment
Phase structure and real-time dynamics of the massive Thirring model in 1+1 dimensions using the tensor-network method
We present concluding results from our study for zero-temperature phase
structure of the massive Thirring model in 1+1 dimensions with staggered
regularisation. Employing the method of matrix product states, several
quantities, including two types of correlators, are investigated, leading to
numerical evidence of a Berezinskii-Kosterlitz-Thouless phase transition.
Exploratory results for real-time dynamics pertaining to this transition,
obtained using the approaches of variational uniform matrix product state and
time-dependent variational principle, are also discussed.Comment: 7 pages, 4 figures, contribution to the 37th International Symposium
on Lattice Field Theory (LATTICE2019), 16-22 June 2019, Wuhan, Chin
The Macrobrachium rosenbergii nodavirus: a detailed review of structure, infectivity, host immunity, diagnosis and prevention
The Macrobrachium rosenbergii nodavirus causes white tail disease, which primarily infects giant freshwater prawns, Macrobrachium rosenbergii. The infection leads to almost 100% mortality in post-larvae, causing significant economic losses in aquaculture farms. To develop effective measures against outbreaks, a good understanding of the virus is essential. In this review, we discuss key aspects of the Macrobrachium rosenbergii nodavirus including its structure, mechanisms of transmission and infection and common strategies for detection and prevention of outbreaks. Structurally, cryogenic electron microscopy revealed that the nodavirus has a T = 3 icosahedral structure with dimeric blade-like spikes on its surface. Homology modelling comparing wild-type and enzymatically cleaved Macrobrachium rosenbergii nodavirus-like particles revealed the significance of these spikes or protruding domains for binding. In vitro and in vivo studies have identified key aspects of Macrobrachium rosenbergii nodavirus infectivity, including (i) the viral binding targets such as transglutaminase and caveolin-1, (ii) utilisation of B2-like proteins in promoting infectivity and intracellular migration, (iii) replication mechanisms and (iv) co-infection with the extra small virus. Though susceptible at a post-larvae stage, adult Macrobrachium rosenbergii is immune to Macrobrachium rosenbergii nodavirus infection. During outbreaks, polymerase chain reaction and in situ hybridisation-based detection techniques are commonly used to identify infected populations. Currently, the most useful strategies for an outbreak are physical biosecurity measures and prophylaxis such as vaccination and immunostimulants. Finally, critical gaps in research include development of immortalised shrimp cell models, elucidation of time-resolved protein changes post-infection and development of therapies to treat infections to mitigate economic losses during outbreaks
Socioeconomic impacts linked to land use and land use changes affecting blue carbon ecosystems in Southeast Asia: A systematic map
Land use and land use changes are the main drivers of blue carbon ecosystem (BCE) loss and degradation, which is frequently justified on the pretext of advancing economic and social development. However, there is still a lack of comprehensive investigation of the impacts of these changes on humans and communities, especially in Southeast Asia (SEA). It is also unclear how many studies have accounted for the interconnectedness of BCEs with adjacent or upstream ecosystems, as well as the potential for cascading impacts to occur across physical, chemical, and biological connections. This information is useful to ensure holistic coastal land use planning which achieves the desired outcomes of balancing environmental sustainability, economic growth, and social equity, while effectively managing risks, engaging communities, and aligning policies for long-term resilience and resource efficiency
New genetic loci link adipose and insulin biology to body fat distribution.
Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms
Impact of Cigarette Smoke Exposure on Innate Immunity: A Caenorhabditis elegans Model
BACKGROUND: Cigarette smoking is the major cause of chronic obstructive pulmonary disease (COPD) and lung cancer. Respiratory bacterial infections have been shown to be involved in the development of COPD along with impaired airway innate immunity. METHODOLOGY/PRINCIPAL FINDINGS: To address the in vivo impact of cigarette smoke (CS) exclusively on host innate defense mechanisms, we took advantage of Caenorhabditis elegans (C. elegans), which has an innate immune system but lacks adaptive immune function. Pseudomonas aeruginosa (PA) clearance from intestines of C. elegans was dampened by CS. Microarray analysis identified 6 candidate genes with a 2-fold or greater reduction after CS exposure, that have a human orthologue, and that may participate in innate immunity. To confirm a role of CS-down-regulated genes in the innate immune response to PA, RNA interference (RNAi) by feeding was carried out in C. elegans to inhibit the gene of interest, followed by PA infection to determine if the gene affected innate immunity. Inhibition of lbp-7, which encodes a lipid binding protein, resulted in increased levels of intestinal PA. Primary human bronchial epithelial cells were shown to express mRNA of human Fatty Acid Binding Protein 5 (FABP-5), the human orthologue of lpb-7. Interestingly, FABP-5 mRNA levels from human smokers with COPD were significantly lower (p = 0.036) than those from smokers without COPD. Furthermore, FABP-5 mRNA levels were up-regulated (7-fold) after bacterial (i.e., Mycoplasma pneumoniae) infection in primary human bronchial epithelial cell culture (air-liquid interface culture). CONCLUSIONS: Our results suggest that the C. elegans model offers a novel in vivo approach to specifically study innate immune deficiencies resulting from exposure to cigarette smoke, and that results from the nematode may provide insight into human airway epithelial cell biology and cigarette smoke exposure
Observation of GRB 221009A early afterglow in X/-ray energy band
The early afterglow of a Gamma-ray burst (GRB) can provide critical
information on the jet and progenitor of the GRB. The extreme brightness of GRB
221009A allows us to probe its early afterglow in unprecedented detail. In this
letter, we report comprehensive observation results of the early afterglow of
GRB 221009A (from +660 s to +1860 s, where is the
\textit{Insight}-HXMT/HE trigger time) in X/-ray energy band (from 20
keV to 20 MeV) by \textit{Insight}-HXMT/HE, GECAM-C and \textit{Fermi}/GBM. We
find that the spectrum of the early afterglow in 20 keV-20 MeV could be well
described by a cutoff power-law with an extra power-law which dominates the low
and high energy bands respectively. The cutoff power-law is
30 keV and the power-law photon index is 1.8 throughout the early
afterglow phase. By fitting the light curves in different energy bands, we find
that a significant achromatic break (from keV to TeV) is required at +
1246 s (i.e. 1021 s since the afterglow starting time =+225 s), providing compelling evidence of a jet break. Interestingly,
both the pre-break and post-break decay slopes vary with energy, and these two
slopes become closer in the lower energy band, making the break less
identifiable. Intriguingly, the spectrum of the early afterglow experienced a
slight hardening before the break and a softening after the break. These
results provide new insights into the understanding of this remarkable GRB.Comment: Accepted for publication in ApJ Letters on 19-Jan-2024, 11 pages, 7
figures and 2 table
An Indo-Pacific coral spawning database.
The discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology
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