Two new species and additional distributional records of Acmopolynema Ogloblin (Hymenoptera: Mymaridae) from India

Two new species of Acmopolynema Ogloblin (Hymenoptera: Mymaridae), Acmopolynema pteron Manickavasagam & Palanivel sp. nov. and Acmopolynema pseudotachikawai Manickavasagam & Palanivel sp. nov., are described from India; a revised key to Indian species of the genus is provided. Acmopolynema shrawastianum Hayat & Anis syn. nov. is synonymized under Acmopolynema indochinense (Soyka); Acmopolynema orchidea Triapitsyn & Berezovskiy is reported from India, and new distributional records of Acmopolynema tachikawai Taguchi from Brunei and India are also given.www.zoobank.org/urn:lsid:zoobank.org:pub:3098457A-CA39-49CD-AEF1-19E788C33B78     

A progeroid syndrome in mice is caused by defects in A-type lamins

Numerous studies of the underlying causes of ageing have been attempted by examining diseases associated with premature ageing, such as Werner's syndrome and Hutchinson-Gilford progeria syndrome (HGPS). HGPS is a rare genetic disorder resulting in phenotypes suggestive of accelerated ageing, including shortened stature, craniofacial disproportion, very thin skin, alopecia and osteoporosis, with death in the early teens predominantly due to atherosclerosis. However, recent reports suggest that developmental abnormalities may also be important in HGPS. Here we describe the derivation of mice carrying an autosomal recessive mutation in the lamin A gene (Lmna) encoding A-type lamins, major components of the nuclear lamina. Homozygous mice display defects consistent with HGPS, including a marked reduction in growth rate and death by 4 weeks of age. Pathologies in bone, muscle and skin are also consistent with progeria. The Lmna mutation resulted in nuclear morphology defects and decreased lifespan of homozygous fibroblasts, suggesting premature cell death. Here we present a mouse model for progeria that may elucidate mechanisms of ageing and development in certain tissue types, especially those developing from the mesenchymal cell lineage.     

Morphological and molecular separation between Macrocamptoptera grangeri Soyka and M. metotarsa (Girault) (Hymenoptera: Mymaridae)

ABSTRACT

Based on morphological and molecular evidence, the European fairyfly Herulia sundholmi Hedqvist syn. n. (Hymenoptera: Mymaridae) is removed from previous synonymy with the Nearctic Macrocamptoptera metotarsa (Girault), and synonymised with the Palaearctic M. grangeri Soyka, which is newly recorded from Georgia, Slovakia and Spain. Macrocamptoptera bulagarica (Donev) syn. n., known from Bulgaria and Italy, is also synonymised with M. grangeri. An updated key to females of the three currently recognised species of the rarely collected genus Macrocamptoptera Girault is given.     

Strong contributors to network persistence are the most vulnerable to extinction

The architecture of mutualistic networks facilitates coexistence of individual participants by minimizing competition relative to facilitation. However, it is not known whether this benefit is received by each participant node in proportion to its overall contribution to network persistence. This issue is critical to understanding the trade-offs faced by individual nodes in a network. We address this question by applying a suite of structural and dynamic methods to an ensemble of flowering plant/insect pollinator networks. Here we report two main results. First, nodes contribute heterogeneously to the overall nested architecture of the network. From simulations, we confirm that the removal of a strong contributor tends to decrease overall network persistence more than the removal of a weak contributor. Second, strong contributors to collective persistence do not gain individual survival benefits but are in fact the nodes most vulnerable to extinction. We explore the generality of these results to other cooperative networks by analysing a 15-year time series of the interactions between designer and contractor firms in the New York City garment industry. As with the ecological networks, a firm's survival probability decreases as its individual nestedness contribution increases. Our results, therefore, introduce a new paradox into the study of the persistence of cooperative networks, and potentially address questions about the impact of invasive species in ecological systems and new competitors in economic systems.     

Resolving the time when an electron exits a tunnelling barrier

The tunnelling of a particle through a barrier is one of the most fundamental and ubiquitous quantum processes. When induced by an intense laser field, electron tunnelling from atoms and molecules initiates a broad range of phenomena such as the generation of attosecond pulses, laser-induced electron diffraction and holography. These processes evolve on the attosecond timescale (1?attosecond?≡?1?as = 10(-18)?seconds) and are well suited to the investigation of a general issue much debated since the early days of quantum mechanics--the link between the tunnelling of an electron through a barrier and its dynamics outside the barrier. Previous experiments have measured tunnelling rates with attosecond time resolution and tunnelling delay times. Here we study laser-induced tunnelling by using a weak probe field to steer the tunnelled electron in the lateral direction and then monitor the effect on the attosecond light bursts emitted when the liberated electron re-encounters the parent ion. We show that this approach allows us to measure the time at which the electron exits from the tunnelling barrier. We demonstrate the high sensitivity of the measurement by detecting subtle delays in ionization times from two orbitals of a carbon dioxide molecule. Measurement of the tunnelling process is essential for all attosecond experiments where strong-field ionization initiates ultrafast dynamics. Our approach provides a general tool for time-resolving multi-electron rearrangements in atoms and molecules--one of the key challenges in ultrafast science.