Characteristics of Deforestation in the Democratic People’s Republic of Korea (North Korea) between the 1980s and 2000s

There has been a significant lack of land cover change studies in relation to deforestation in the Democratic People’s Republic of Korea (North Korea). The purpose of this study is to characterise deforestation in North Korea through land cover change trajectory and spatial analysis. We used three 30-m gridded land cover data sets for North Korea representing the conditions of the late 1980s, 1990s, and 2000s, respectively, as well as a digital elevation model. We examined the land cover trajectories during the two decades, i.e. which land cover became which at the pixel level. In addition, we calculated topographic characteristics of deforested pixels. Major findings from the study are summarised as follows: (1) net forest loss in North Korea slowed since the 1990s, whereas land cover changes were active; (2) as a result of deforestation, forest land cover became mostly agricultural and grassland; (3) expansion of agricultural land cover continued during the time; and (4) elevation and slope of deforested areas decreased slightly in the latter decade. The key contribution of the study is that it has demonstrated which land cover became which at the 30-m pixel level, complementing existing studies that examined overall forest stock in North Korea

The Globular Cluster System of NGC 1399 IV. Some noteworthy objects

We present 8 bright globular clusters and/or objects of less familiar nature which we found in the course of scrutinizing the globular cluster system of NGC 1399. These objects are morphologically striking, either by their sizes or by other structural properties. Some of them may be candidates for stripped dwarf galaxy nuclei, emphasizing the possible role of accretion in the NGC 1399 cluster system. They are all highly interesting targets for further deep spectroscopy or HST-imaging. Since these objects have been found within an area of only 42 arcmin**2, we expect many more still to be detected in a full census of the NGC 1399 cluster system.Comment: 6 pages, 3 figures, accepted by A&A (Research Note

Thermodynamics of Exotic Black Holes, Negative Temperature, and Bekenstein-Hawking Entropy

Recently, exotic black holes whose masses and angular momenta are interchanged have been found, and it is known that their entropies depend only on the $inner$ horizon areas. But a basic problem of these entropies is that the second law of thermodynamics is not guaranteed, in contrast to the Bekenstein-Hawking entropy. Here, I find that there is another entropy formula which recovers the usual Bekenstein-Hawking form, but the characteristic angular velocity and temperature are identified with those of the inner horizon, in order to satisfy the first law of black hole thermodynamics. The temperature has a $negative$ value, due to an upper bound of mass as in spin systems, and the angular velocity has a $lower$ bound. I show that one can obtain the same entropy formula from a conformal field theory computation, based on classical Virasoro algebras. I also describe several unanswered problems and some proposals for how these might be addressed.Comment: Explicit discussuin of the remanining open questions added, enlarged references accordingly, accepted in Phys. Lett.

Kinematical and chemical vertical structure of the Galactic thick disk II. A lack of dark matter in the solar neighborhood

We estimated the dynamical surface mass density Sigma at the solar position between Z=1.5 and 4 kpc from the Galactic plane, as inferred from the kinematics of thick disk stars. The formulation is exact within the limit of validity of a few basic assumptions. The resulting trend of Sigma(Z) matches the expectations of visible mass alone, and no dark component is required to account for the observations. We extrapolate a dark matter (DM) density in the solar neighborhood of 0+-1 mM_sun pc^-3, and all the current models of a spherical DM halo are excluded at a confidence level higher than 4sigma. A detailed analysis reveals that a small amount of DM is allowed in the volume under study by the change of some input parameter or hypothesis, but not enough to match the expectations of the models, except under an exotic combination of non-standard assumptions. Identical results are obtained when repeating the calculation with kinematical measurements available in the literature. We demonstrate that a DM halo would be detected by our method, and therefore the results have no straightforward interpretation. Only the presence of a highly prolate (flattening q>2) DM halo can be reconciled with the observations, but this is highly unlikely in LambdaCDM models. The results challenge the current understanding of the spatial distribution and nature of the Galactic DM. In particular, our results may indicate that any direct DM detection experiment is doomed to fail, if the local density of the target particles is negligible.Comment: Accepted for publication in the Astrophysical Journa

Dynamical population synthesis: Constructing the stellar single and binary contents of galactic field populations

[abridged] The galactic field's late-type stellar single and binary population is calculated on the supposition that all stars form as binaries in embedded star clusters. A recently developed tool (Marks, Kroupa & Oh) is used to evolve the binary star distributions in star clusters for a few Myr so that a particular mixture of single and binary stars is achieved. On cluster dissolution the population enters the galactic field with these characteristics. The different contributions of single stars and binaries from individual star clusters which are selected from a power-law embedded star cluster mass function are then added up. This gives rise to integrated galactic field binary distribution functions (IGBDFs) resembling a galactic field's stellar content (Dynamical Population Synthesis). It is found that the binary proportion in the galactic field of a galaxy is larger the lower the minimum cluster mass, the lower the star formation rate, the steeper the embedded star cluster mass function and the larger the typical size of forming star clusters in the considered galaxy. In particular, period-, mass-ratio- and eccentricity IGBDFs for the Milky Way are modelled. The afore mentioned theoretical IGBDFs agree with independently observed distributions. Of all late-type binaries, 50% stem from M<300M_sun clusters, while 50% of all single stars were born in M>10^4M_sun clusters. Comparison of the G-dwarf and M-dwarf binary population indicates that the stars formed in mass-segregated clusters. In particular it is pointed out that although in the present model all M-dwarfs are born in binary systems, in the Milky Way's Galactic field the majority ends up being single stars. This work predicts that today's binary frequency in elliptical galaxies is lower than in spiral and in dwarf-galaxies. The period and mass-ratio distributions in these galaxies are explicitly predicted.Comment: 14 pages, 9 figures, accepted for publication in MNRA

Evaluation of Preterm Delivery between 32+0-33+6 Weeks of Gestation

Preterm labor after 34 weeks of gestation has shown no great difference from full-term labor in terms of neonatal morbidity and mortality when proper antepartum management (antibiotics or steroids treatment) is done. However, various studies have discussed different views on the risks and safety of preterm delivery at 32+0-33+6 weeks of gestation. We evaluated the complications of different preterm groups that included the neonates born at 32+0-33+6 weeks of gestation (142), stratified randomly selected neonates born at 34+0-36+6 weeks of gestation (267) and neonates born after 37+0 weeks of gestation (356) at our hospital between December 1999 and April 2006. As a result, it was found that neonates born at 34+0-36+6 weeks of gestation showed no great difference from infants born at full term. However, neonates born at 32+0-33+6 weeks were more likely to be admitted to neonatal intensive care unit or develop neonatal complications significantly than the neonates born at 34+0-36+6 weeks and at full term. Therefore, it is suggested that neonates born at 32+0-33+6 weeks have higher risk of neonatal complications following their preterm labor than those born at later than 34+0 weeks. Thus, it would be difficult to accept the idea that preterm labor at 32+0-33+6 weeks is safe

Evolution of Tachyon Kink with Electric Field

We investigate the decay of an inhomogeneous D1-brane wrapped on a $S^1$ with an electric field. The model that we consider consists of an array of tachyon kink and anti-kink with a constant electric flux. Beginning with an initially static configuration, we numerically evolve the tachyon field with some perturbations under a fixed boundary condition at diametrically opposite points on the circle $S^1$. When the electric flux is smaller than the critical value, the tachyon kink becomes unstable; the tachyon field rolls down the potential, and the lower dimensional D0- and $\bar {\rm D}0$-brane become thin, which resembles the caustic formation known for this type of the system in the literature. For the supercritical values of the electric flux, the tachyon kink remains stable.Comment: 27 pages, 8 figures, some changes, one reference added, version to appear in JHE

Planetary Nebulae in Face-On Spiral Galaxies. III. Planetary Nebula Kinematics and Disk Mass

Much of our understanding of dark matter halos comes from the assumption that the mass-to-light ratio (M/L) of spiral disks is constant. The best way to test this hypothesis is to measure the disk surface mass density directly via the kinematics of old disk stars. To this end, we have used planetary nebulae (PNe) as test particles and have measured the vertical velocity dispersion (sigma_z) throughout the disks of five nearby, low-inclination spiral galaxies: IC 342, M74 (NGC 628), M83 (NGC 5236), M94 (NGC 4736), and M101 (NGC 5457). By using HI to map galactic rotation and the epicyclic approximation to extract sigma_z from the line-of-sight dispersion, we find that, with the lone exception of M101, our disks do have a constant M/L out to ~3 optical scale lengths. However, once outside this radius, sigma_z stops declining and becomes flat with radius. Possible explanations for this behavior include an increase in the disk mass-to-light ratio, an increase in the importance of the thick disk, and heating of the thin disk by halo substructure. We also find that the disks of early type spirals have higher values of M/L and are closer to maximal than the disks of later-type spirals, and that the unseen inner halos of these systems are better fit by pseudo-isothermal laws than by NFW models.Comment: 18 pages, 15 figures, 5 tables; accepted to Ap

MDM: A Mode Diagram Modeling Framework

Periodic control systems used in spacecrafts and automotives are usually period-driven and can be decomposed into different modes with each mode representing a system state observed from outside. Such systems may also involve intensive computing in their modes. Despite the fact that such control systems are widely used in the above-mentioned safety-critical embedded domains, there is lack of domain-specific formal modelling languages for such systems in the relevant industry. To address this problem, we propose a formal visual modeling framework called mode diagram as a concise and precise way to specify and analyze such systems. To capture the temporal properties of periodic control systems, we provide, along with mode diagram, a property specification language based on interval logic for the description of concrete temporal requirements the engineers are concerned with. The statistical model checking technique can then be used to verify the mode diagram models against desired properties. To demonstrate the viability of our approach, we have applied our modelling framework to some real life case studies from industry and helped detect two design defects for some spacecraft control systems.Comment: In Proceedings FTSCS 2012, arXiv:1212.657

Using XDAQ in Application Scenarios of the CMS Experiment

XDAQ is a generic data acquisition software environment that emerged from a rich set of of use-cases encountered in the CMS experiment. They cover not the deployment for multiple sub-detectors and the operation of different processing and networking equipment as well as a distributed collaboration of users with different needs. The use of the software in various application scenarios demonstrated the viability of the approach. We discuss two applications, the tracker local DAQ system for front-end commissioning and the muon chamber validation system. The description is completed by a brief overview of XDAQ.Comment: Conference CHEP 2003 (Computing in High Energy and Nuclear Physics, La Jolla, CA