Partial mitochondrial DNA sequences suggest the existence of a cryptic species within the Leucosphyrus group of the genus Anopheles (Diptera: Culicidae), forest malaria vectors, in northern Vietnam

<p>Abstract</p> <p>Background</p> <p>During the last decade, Southeast Asian countries have been very successful in reducing the burden of malaria. However, malaria remains endemic in these countries, especially in remote and forested areas. The Leucosphyrus group of the genus <it>Anopheles </it>harbors the most important malaria vectors in forested areas of Southeast Asia. In Vietnam, previous molecular studies have resulted in the identification of only <it>Anopheles dirus sensu stricto </it>(previously known as <it>An. dirus </it>species A) among the Leucosphyrus group members. However, Vietnamese entomologists have recognized that mosquitoes belonging to the Leucosphyrus group in northern Vietnam exhibit morphological characteristics similar to those of <it>Anopheles takasagoensis</it>, which has been reported only from Taiwan. Here, we aimed to confirm the genetic and morphological identities of the members of the Leucosphyrus group in Vietnam.</p> <p>Results</p> <p>In the molecular phylogenetic trees reconstructed using partial <it>COI </it>and <it>ND6 </it>mitochondrial gene sequences, samples collected from southern and central Vietnam clustered together with GenBank sequences of <it>An. dirus </it>that were obtained from Thailand. However, samples from northern Vietnam formed a distinct clade separated from both <it>An. dirus </it>and <it>An. takasagoensis </it>by other valid species.</p> <p>Conclusions</p> <p>The results suggest the existence of a cryptic species in northern Vietnam that is morphologically similar to, but phylogenetically distant from both <it>An. dirus </it>and <it>An. takasagoensis</it>. We have tentatively designated this possible cryptic species as <it>Anopheles </it>aff. <it>takasagoensis </it>for convenience, until a valid name is assigned. However, it is difficult to distinguish the species solely on the basis of morphological characteristics. Further studies on such as karyotypes and polytene chromosome banding patterns are necessary to confirm whether <it>An</it>. aff. <it>takasagoensis </it>is a valid species. Moreover, studies on (1) the geographic distribution, which is potentially spreading along the Vietnam, China, Laos, and Myanmar borders; (2) morphological and ecological characteristics; and (3) vectorial capacity of this newly identified cryptic species of <it>An. dirus</it>, which is one of the most important malaria vectors in the mainland of Southeast Asia, are necessary for planning efficient malaria vector control programs in this region.</p

Magnetized Fast Isochoric Laser Heating for Efficient Creation of Ultra-High-Energy-Density States

The quest for the inertial confinement fusion (ICF) ignition is a grand challenge, as exemplified by extraordinary large laser facilities. Fast isochoric heating of a pre-compressed plasma core with a high-intensity short-pulse laser is an attractive and alternative approach to create ultra-high-energy-density states like those found in ICF ignition sparks. This avoids the ignition quench caused by the hot spark mixing with the surrounding cold fuel, which is the crucial problem of the currently pursued ignition scheme. High-intensity lasers efficiently produce relativistic electron beams (REB). A part of the REB kinetic energy is deposited in the core, and then the heated region becomes the hot spark to trigger the ignition. However, only a small portion of the REB collides with the core because of its large divergence. Here we have demonstrated enhanced laser-to-core energy coupling with the magnetized fast isochoric heating. The method employs a kilo-tesla-level magnetic field that is applied to the transport region from the REB generation point to the core which results in guiding the REB along the magnetic field lines to the core. 7.7 $\pm$ 1.3 % of the maximum coupling was achieved even with a relatively small radial area density core ($\rho R$ $\sim$ 0.1 g/cm$^2$). The guided REB transport was clearly visualized in a pre-compressed core by using Cu-$K_\alpha$ imaging technique. A simplified model coupled with the comprehensive diagnostics yields 6.2\% of the coupling that agrees fairly with the measured coupling. This model also reveals that an ignition-scale areal density core ($\rho R$ $\sim$ 0.4 g/cm$^2$) leads to much higher laser-to-core coupling ($>$ 15%), this is much higher than that achieved by the current scheme

Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system

A counter-propagating laser-beam platform using a spherical plasma mirror was developed for the kilojoule-class petawatt LFEX laser. The temporal and spatial overlaps of the incoming and redirected beams were measured with an optical interferometer and an x-ray pinhole camera. The plasma mirror performance was evaluated by measuring fast electrons, ions, and neutrons generated in the counter-propagating laser interaction with a Cu-doped deuterated film on both sides. The reflectivity and peak intensity were estimated as ∼50% and ∼5 × 1018 W/cm2, respectively. The platform could enable studies of counter-streaming charged particles in high-energy-density plasmas for fundamental and inertial confinement fusion research.Kojima S., Abe Y., Miura E., et al. Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system. Optics Express 30, 43491 (2022); https://doi.org/10.1364/oe.475945

Direct fast heating efficiency of a counter-imploded core plasma employing a laser for fast ignition experiments (LFEX)

Fast heating efficiency when a pre-imploded core is directly heated with an ultraintense laser (heating laser) was investigated. \u27Direct heating\u27 means that a heating laser hits a pre-imploded core without applying either a laser guiding cone or an external field. The efficiency, η, is defined as the increase in the internal core energy divided by the energy of the heating laser. Six beams (output of 1.6 kJ) from the GEKKO XII (GXII) green laser system at the Institute of Laser Engineering (ILE), Osaka University were applied to implode a spherical deuterated polystyrene (CD) shell target to form a dense core. The DD-reacted protons and the core x-ray emissions showed a core density of 2.8 ± 0.7 g cm−3, or 2.6 times the solid density. Furthermore, DD-reacted thermal neutrons were utilized to estimate the core temperature between 600 and 750 eV. Thereafter, the core was directly heated by a laser for fast-ignition experiments (LFEX, an extremely energetic ultrashort pulse laser) at ILE with its axis lying along or perpendicular to the GXII bundle axis, respectively. The former and latter laser configurations were termed \u27axial\u27 and \u27transverse modes\u27, respectively. The η was estimated from three independent methods: (1) the core x-ray emission, (2) the thermal neutron yield, and (3) the runaway hot electron spectra. For the axial mode, 0.8%< η <2.1% at low power (low LFEX energy) and 0.4%< η <2.5% at high power (high LFEX energy). For the transverse mode, 2.6%< η <7% at low power and 1.5%< η <7.7% at high power. Their efficiencies were compared with that in the uniform implosion mode using 12 GXII beams, 6% < η <12%, which appeared near to the η for the transverse mode, except that the error bar is very large