DroneBased Parcel Delivery Using the Rooftops of City Buildings: Model and Solution

In general, the demand for delivery cannot be fulfilled efficiently due to the excessive traffic in dense urban areas. Therefore, many innovative concepts for intelligent transportation of freight have recently been developed. One of these concepts relies on drone-based parcel delivery using rooftops of city buildings. To apply drone logistics system in cities, the operation design should be adequately prepared. In this regard, a mixed integer programming model for drone operation planning and a heuristic based on block stacking are newly proposed to provide solutions. Additionally, numerical experiments with three different problem sizes are conducted to check the feasibility of the proposed model and to assess the performance of the proposed heuristic. The experimental results show that the proposed model seems to be viable and that the developed heuristic provides very good operation plans in terms of the optimality gap and the computation time. Document type: Articl

Hawking radiation as tunneling from charged black holes in 0A string theory

There has been much work on explaining Hawking radiation as a quantum tunneling process through horizons. Basically, this intuitive picture requires the calculation of the imaginary part of the action for outgoing particle. And two ways are known for achieving this goal: the null-geodesic method and the Hamilton-Jacobi method. We apply these methods to the charged black holes in 2D dilaton gravity which is originated from the low energy effective theory of type 0A string theory. We derive the correct Hawking temperature of the black holes including the effect of the back reaction of the radiation, and obtain the entropy by using the 1st law of black hole thermodynamics. For fixed-charge ensemble, the 0A black holes are free of phase transition and thermodynamically stable regardless of mass-charge ratio. We show this by interpreting the back reaction term as the inverse of the heat capacity of the black holes. Finally, the possibility of the phase transition in the fixed-potential ensemble is discussed.Comment: 12 pages; v2: references added, revised with some changes in formula and unaltered conclusions, to be published in Phys. Lett.

Two-dimensional Black Holes in a Higher Derivative Gravity and Matrix Model

We construct perturbatively a class of charged black hole solutions in type 0A string theory with higher derivative terms. They have extremal limit, where the solution interpolates smoothly between near horizon AdS_2 geometry and the asymptotic linear dilaton geometry. We compute the free energy and the entropy of those solution using various methods. In particular, we show that there is no correction in the leading term of the free energy in the large charge limit. This supports the duality of the type 0A strings on the extremal black hole and the 0A matrix model in which the tree level free energy is exact without any alpha' corrections.Comment: Latex, 19 page

Acute Hemorrhagic Conjunctivitis caused by Coxsackievirus A24 Variant, South Korea, 2002

In summer 2002, a nationwide outbreak of acute hemorrhagic conjunctivitis occurred in South Korea. The etiologic agent was confirmed as coxsackievirus A24 variant (CA24v) by virus isolation and sequencing of a part of the VP1 gene. Phylogentic analysis, based on the protease 3C sequences, showed that the Korean isolates were clustered into a lineage distinct from the CA24v isolates reported in previous outbreaks in Asia

Recent Short Term Global Aerosol Trends over Land and Ocean Dominated by Biomass Burning

NASA's MODIS instrument on board the Terra satellite is one of the premier tools to assess aerosol over land and ocean because of its high quality calibration and consistency. We analyze Terra-MODIS's seven year record of aerosol optical depth (AOD) observations to determine whether global aerosol has increased or decreased during this period. This record shows that AOD has decreased over land and increased over ocean. Only the ocean trend is statistically significant and corresponds to an increase in AOD of 0.009, or a 15% increase from background conditions. The strongest increasing trends occur over regions and seasons noted for strong biomass burning. This suggests that biomass burning aerosol dominates the increasing trend over oceans and mitigates the otherwise mostly negative trend over the continents

How Well Does NASA GEOS Model Perform in Simulating Dust Deposition into the Tropical Atlantic Ocean?

Massive dust emitted from North Africa can transport long distances across the tropical Atlantic Ocean, reaching the Americas. Dust deposition along the transit adds microorganisms and essential nutrients to marine ecosystem, which has important implications for biogeochemical cycle and climate. However, assessing the dust-ecosystemclimate interactions has been hindered in part by the paucity of dust deposition measurements and large uncertainties associated with oversimplified representations of dust processes in current models. We have recently produced a unique dataset of seasonal dust deposition flux and dust loss frequency into the tropical Atlantic Ocean at a nominal resolution of 200 km x 500 km by using the decade-long (2007-2016) record of aerosol three-dimensional distribution from four satellite sensors, namely CALIOP, MODIS, MISR, and IASI. On the basis of the ten-year average, the yearly dust deposition into the tropical Atlantic Ocean is estimated at 98-153 Tg. The dust deposition shows large spatial and temporal (on seasonal and interannual scale) variability. The satellite observations also yield an estimate of annual mean dust loss frequency of 0.052 ~ 0.078 d-1, a useful diagnostic that makes it possible to disentangle the dust transport and removal processes from the dust emissions when identifying the major factors contributing to the uncertainties and biases in the model simulated dust deposition. In this study, we use the dataset along with in situ and remote sensing observations to assess how well NASA GEOS model performs in simulating trans-Atlantic dust transport and deposition. We found that the GEOS modeling of dust deposition falls within the range of satellite-based estimates. However, this reasonable agreement in dust deposition is a compensation of the model's underestimate of dust emissions and overestimate of dust removal efficiency. Further, the overestimate of dust removal efficiency results largely from the model's overestimate of rainfall rate. Our results provide insights into the model's deficiencies at process level, which could better guide model improvements

Asian and trans-Pacific dust: a multi-model and multi-remote sensing observation analysis

Dust is one of the dominant aerosol types over Asia and the North Pacific Ocean, but quantitative estimation of dust distribution and its contribution to the total regional aerosol load from observations is challenging due to the presence of significant anthropogenic and natural aerosols and the frequent influence of clouds over the region. This study presents the dust aerosol distributions over Asia and the North Pacific using simulations from five global models that participated in the AeroCom phase II model experiments, and from multiple satellite remote-sensing and ground-based measurements of total aerosol optical depth (AOD) and dust optical depth (DOD). We examine various aspects of aerosol and dust presence in our study domain: (1) the horizontal distribution, (2) the longitudinal gradient during trans-Pacific transport, (3) seasonal variations, (4) vertical profiles, and (5) model-simulated dust life cycles. This study reveals that the diversity of DOD is mostly driven by the diversity of the dust source followed by residence time and mass extinction efficiency

Dynamical formation and evolution of (2+1)-dimensional charged black holes

In this paper, we investigate the dynamical formation and evolution of 2 + 1-dimensional charged black holes. We numerically study dynamical collapses of charged matter fields in an anti de Sitter background and note the formation of black holes using the double-null formalism. Moreover, we include re-normalized energy-momentum tensors assuming the S-wave approximation to determine thermodynamical back-reactions to the internal structures. If there is no semi-classical effects, the amount of charge determines the causal structures. If the charge is sufficiently small, the causal structure has a space-like singularity. However, as the charge increases, an inner Cauchy horizon appears. If we have sufficient charge, we see a space-like outer horizon and a time-like inner horizon, and if we give excessive charge, black hole horizons disappear. We have some circumstantial evidences that weak cosmic censorship is still satisfied, even for such excessive charge cases. Also, we confirm that there is mass inflation along the inner horizon, although the properties are quite different from those of four-dimensional cases. Semi-classical back-reactions will not affect the outer horizon, but they will affect the inner horizon. Near the center, there is a place where negative energy is concentrated. Thus, charged black holes in three dimensions have two types of curvature singularities in general: via mass inflation and via a concentration of negative energy. Finally, we classify possible causal structures.Comment: 40 pages, 15 figure

Satellite-based Estimates of Dust Deposition Into Tropical Atlantic Ocean

No abstract availabl

The impact of human EGFR kinase domain mutations on lung tumorigenesis and in vivo sensitivity to EGFR-targeted therapies

SummaryTo understand the role of human epidermal growth factor receptor (hEGFR) kinase domain mutations in lung tumorigenesis and response to EGFR-targeted therapies, we generated bitransgenic mice with inducible expression in type II pneumocytes of two common hEGFR mutants seen in human lung cancer. Both bitransgenic lines developed lung adenocarcinoma after sustained hEGFR mutant expression, confirming their oncogenic potential. Maintenance of these lung tumors was dependent on continued expression of the EGFR mutants. Treatment with small molecule inhibitors (erlotinib or HKI-272) as well as prolonged treatment with a humanized anti-hEGFR antibody (cetuximab) led to dramatic tumor regression. These data suggest that persistent EGFR signaling is required for tumor maintenance in human lung adenocarcinomas expressing EGFR mutants