The Puerto Rico Plain Pigeon Patagioenas inornata wetmorei suffered a severe population decline after hurricanes Irma and Maria in September 2017. We used distance sampling to estimate abundance (density and population size) in April–June 1986−2024, accounting for changes in detection probability. We used the distance-sampling abundance estimates to populate a Bayesian state–space logistic model and update posterior estimates of population carrying capacity, maximum population growth rate, population recovery time, and predicted abundance in April–June 2025−2034, accounting for observation and process variances. In addition, we used predicted abundance to assess potential extinction risk (probability Pr[N2025−2034 = 0|data]), population self-sustainability above 5,000 individuals (Pr[N2025−2034 >5,000|data]), and population surpassing the 2.5th percentile of carrying capacity (Pr[N2025−2034 >30,000|data]). The population has not recovered from the hurricanes, with estimated density averaging 0.0015 individuals/ha (bootstrapped standard error [SE] = 0.0006) and population size averaging 1,097 individuals (SE = 455) at the 749,000-ha survey region in April–June 2018−2024. Posterior mean estimates were 41,580 individuals (Markov Chain Monte Carlo standard deviation [SD] = 8,052) for population carrying capacity, 0.183 (SD = 0.056) for maximum population growth rate, six years (SD = 2) for recovery time, and 7,173 individuals (SD = 12,309) for predicted abundance in April–June 2025−2034. The population may reach self-sustainability levels (range Pr[N2025−2034 >5,000|data] = 0.326−0.631) but currently is undergoing a prolonged bottleneck and may become extinct (range Pr[N2025−2034 = 0|data] = 0.199−0.332), particularly if reproduction continues to be mostly unsuccessful, anthropogenic disturbances remain unabated, and on top of that another devastating hurricane makes landfall during the next 10 years. The Puerto Rico Plain Pigeon subspecies is in urgent need of management aiming to increase and maintain abundance above 5,000 individuals but preferably surpassing the 2.5th percentile of population carrying capacity as in the late 1990s (range Pr[N2025−2034 >30,000|data] = 0.000−0.181).

We present a new radio continuum study of the Large Magellanic Cloud supernova remnant (SNR) MCSNRJ0519–6902. With a diameter of ∼8 pc, this SNR shows a radio ring-like morphology with three bright regions toward the north, east, and south. Its linear polarisation is prominent with average values of 5 ± 1% and 6 ± 1% at 5500 and 9000 MHz, and we find a spectral index of –0.62 ± 0.02, typical of a young SNR. The average rotation measure is estimated at –124 ± 83 rad m–2 and the magnetic field strength at ∼ 11 μG. We also estimate an equipartition magnetic field of 72 ± 5 μG and minimum explosion energy of Emin = 2.6×1048 erg. Finally, we identified an H I cloud that may be associated with MCSNRJ0519–6902, located in the southeastern part of the remnant, along with a potential wind-bubble cavity.

The kinetic stability of collisionless, sloshing beam-ion ($45^\circ$ pitch angle) plasma is studied in a three-dimensional (3-D) simple magnetic mirror, mimicking the Wisconsin high-temperature superconductor axisymmetric mirror experiment. The collisional Fokker–Planck code CQL3D-m provides a slowing-down beam-ion distribution to initialize the kinetic-ion/fluid-electron code Hybrid-VPIC, which then simulates free plasma decay without external heating or fuelling. Over $1$–$10\;\mathrm{\unicode{x03BC} s}$, drift-cyclotron loss-cone (DCLC) modes grow and saturate in amplitude. The DCLC scatters ions to a marginally stable distribution with gas-dynamic rather than classical-mirror confinement. Sloshing ions can trap cool (low-energy) ions in an electrostatic potential well to stabilize DCLC, but DCLC itself does not scatter sloshing beam-ions into the said well. Instead, cool ions must come from external sources such as charge-exchange collisions with a low-density neutral population. Manually adding cool $\mathord {\sim } 1\;\mathrm{keV}$ ions improves beam-ion confinement several-fold in Hybrid-VPIC simulations, which qualitatively corroborates prior measurements from real mirror devices with sloshing ions.

The well-known $abc$-conjecture concerns triples $(a,b,c)$ of nonzero integers that are coprime and satisfy ${a+b+c=0}$. The strong n-conjecture is a generalisation to n summands where integer solutions of the equation ${a_1 + \cdots + a_n = 0}$ are considered such that the $a_i$ are pairwise coprime and satisfy a certain subsum condition. Ramaekers studied a variant of this conjecture with a slightly different set of conditions. He conjectured that in this setting the limit superior of the so-called qualities of the admissible solutions equals $1$ for any n. In this paper, we follow results of Konyagin and Browkin. We restrict to a smaller, and thus more demanding, set of solutions, and improve the known lower bounds on the limit superior: for ${n \geq 6}$ we achieve a lower bound of $\frac 54$; for odd $n \geq 5$ we even achieve $\frac 53$. In particular, Ramaekers’ conjecture is false for every ${n \ge 5}$.

Historians rightfully insist on learning from history. Indeed, history tends to repeat itself - just as mankind stubbornly tends to ignore that fact. Bruce Cumings’ historical take on the succession issue in the DPRK is thus an important and welcome addition to the many different voices that have tried to make sense of what is happening and to provide a glimpse into the future. However, as an economist I know the risks of applying, implicitly or explicitly, the ceteris paribus condition (all other things being equal). Karl Marx, a classical economist but also a historian, saw history repeating itself in the form of a spiral. Developments tend to appear like a repetitive circle if viewed from the top, but vertical change becomes visible if seen from the side. If we try to understand the nature of Kim Jong- un's leadership, we cannot do so without a long-term understanding of the North Korean system. But we should also consider the many differences between the years 1994 and 2012. The world has changed, North Korea has changed, and even the process of preparation for succession differed. We have yet to see whether the long-term systemic currents will dominate, or whether the many details that differ in Kim Jong-un's case will substantially shape the outcome of the political process in Pyongyang. True, doomsayers were wrong in 1994, and we are able to explain why. But at least some of the reasons for their wrong assessment are gone, opening the possibility that they might be right in 2012. Or they might be wrong again - for new reasons. RF

Little more than a year ago, in December 2011, Kim Jong Un was announced as successor to his late father Kim Jong Il. Initial hopes for a change in North Korea's WMD policy faded away after two missile launches in April and December 2012, and the country's third nuclear test in February 2013. Shortly afterwards, wave after wave of threats has been issued by Pyongyang, including the use of nuclear weapons against the United States. Against this background, does it make sense to even think about economic engagement?

We present two articles on the market response to North Korean famine.

Pak Hyun-yong was, by North Korean standards, an entrepreneur. Too much of an entrepreneur. During the famine that ravaged the country in the late 1990s, Mr Pak watched his family die of starvation – first his younger brother, then his older sister's children. Then, eventually, his sister too.

Somehow he pulled through this period, dubbed by the regime as “the arduous march”, and was spurred into taking some very noncommunist, almost subversive action. He began selling noodles.

After the launch of a three-stage rocket in April and the second nuclear test in May 2009 it seems less realistic than ever to think about opening and reform in North Korea. Inter-Korean relations are deteriorating almost daily. Hard-line orthodoxy has been returning to North Korea since late 2005 at an alarming pace as the country enters an era of socialist neoconservativism that emphasizes self-reliance and mass campaigns, cracks down on previously promoted market activities and stresses anti-imperialist struggle more fiercely than throughout most of the last decade.