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Type I secretion systems for microcin export in Gram-negative bacteria transport small antibacterial proteins from the cytoplasm to the extracellular environment in a single step. In nature, each secretion system is generally paired with a specific small protein.

It is commonly recognised that natural history datasets contain locality errors that can compromise the utility of those datasets. However, another source of error in these datasets is taxonomic misidentifications, and this type of error is potentially common, particularly with regards to morphologically conservative species. For example, in the African skinks, the Trachylepis striata and T. varia species complexes each contain morphologically similar species that are commonly confused, despite being genetically distinct. Some species also are partly sympatric, and misidentifications are likely to be especially problematic in those areas. Using DNA barcoding, we assessed misidentification rates between species and applied the updated identifications to known distribution maps to examine whether those maps are accurate representations. Existing banked samples and newly collected samples were DNA barcoded using the mitochondrial 16S gene and supplemented with GenBank data. Identifications were made by matching sequences using haplotype networks that included material from near type localities. The barcode-based identifications were compared with the original identifications recorded for those samples. Taxonomic error was common, particularly in areas of presumed sympatry (error for T. striata species complex: 28%; T. varia species complex: 31%) and this resulted in inaccurately represented species distributions and areas of sympatry. Areas of sympatry were, however, confirmed for T. spilogaster/T. punctatissima, T. striata/T. punctatissima and T. damarana/T. laevigata/T. varia. Our findings corroborate other studies that demonstrate taxonomic error in existing datasets is a significant, but typically unrecognised problem, particularly for morphologically conservative species. This has implications for the utility of historical collections, citizen science records and public databases used in the formulation of species distribution maps, but also for other downstream analyses that rely on these datasets.

Microcins are peptide antibiotics secreted by Gram-negative bacteria that inhibit the growth of neighboring microbes. They are exported from the cytosol to the environment in a one-step process through a specific type I secretion system (T1SS). While the rules governing export of natural or non-native substrates have been resolved for T1SSs that secrete large proteins, relatively little is known about substrate requirements for peptides exported through T1SSs that secrete microcins. Here, we investigate the prototypic microcin V T1SS fromEscherichia coliand show it can export a remarkably wide range of natural and synthetic peptides. We demonstrate that secretion through this system is not affected by peptide charge or hydrophobicity and appears only constrained by peptide length. A varied range of bioactive peptides, including an antibacterial peptide, a microbial signaling factor, a protease inhibitor, and a human hormone, can all be secreted and elicit their intended biological effect. Secretion through this system is not limited toE. coli, and we demonstrate its function in additional Gram-negative species that can inhabit the gastrointestinal tract. Our findings uncover the highly promiscuous nature of peptide export thorough the microcin V T1SS, which has implications for native cargo capacity and use of Gram-negative bacteria for peptide research and delivery.ImportanceMicrocin type I secretion systems in Gram-negative bacteria transport antibacterial peptides from the cytoplasm to the extracellular environment in single step. In nature, each microcin secretion system is generally paired with a specific peptide. We know little about the export capacity of these transporters and how peptide sequence influences secretion. Here, we investigate the microcin V type I secretion system. Remarkably, our studies show this system can export diverse peptides and is only limited by peptide length. Furthermore, we demonstrate that various bioactive peptides can be secreted, and this system can be used in Gram-negative species that colonize the gastrointestinal tract. These finding expand our understanding of secretion through type I systems and their potential uses in peptide applications.

The Great Karoo and Namaqualand of South Africa are home to a species complex of morphologically conserved lizards that occur in allopatry (Karoo: Cordylus aridus, Cordylus cloetei, Cordylus minor; Namaqualand: Cordylus imkeae). However, there are negligible morphological differences and a lack of obvious physical or climatic barriers, particularly among the three Karoo species. We hypothesized that poor geographic coverage in previous studies and lack of an explicit species concept has caused taxonomic inflation. We therefore tested species boundaries by examining multiple criteria: multi-gene phylogenetics, niche distribution modelling and re-examination of diagnostic morphological features with a larger sample size. We found that C. aridus, C. cloetei and C. minor lack diagnosable differences for both genetics and morphology. Distribution modelling, ranging from present day to the last interglacial period, show connectivity has been maintained especially during cooler periods. Conversely, C. imkeae is morphologically diagnosable, genetically distinct and lacks connectivity with the other taxa. By evaluating multiple operational criteria, we conclude that the C. minor species complex comprises only two species, C. minor (with C. aridus and C. cloetei as junior synonyms) and C. imkeae, demonstrating that species defined from inadequate data and lack of an explicit species concept can lead to taxonomic inflation.

Pachydactylus is the most species-rich reptile genus in southern Africa. Most species are habitat specialists adapted to hyper-arid conditions of the Namibian and north-western South African xeric regions. Although a fair number of phylogenetic studies and taxonomic revisions have been published, some species still remain rather enigmatic. In the ten years since the taxonomic revision of the weberi group, some of the species have not been recorded and our knowledge on their distribution, phylogenetic affinities, or intraspecific variability is limited or non-existent. Pachydactylus goodi is one such species. In this study, we report a newly discovered population of P. goodi in the Richtersveld National Park, South Africa, which considerably extends the known range of the species. In addition, the results of our phylogenetic analyses indicate that P. goodi is paraphyletic with respect to P. atorquatus. Although there is a striking colour polymorphism observed between these two species, the level of genetic differentiation within the goodi-atorquatus clade is comparable with intraspecific variability observed in other Pachydactylus species. As a result of these findings, which are further supported by morphological similarity of the two species, we conclude that they represent a single species and synonymise P. goodi with P. atorquatus.

Large laser systems that deliver optical pulses with peak powers exceeding one Petawatt (PW) have been constructed at dozens of research facilities worldwide and have fostered research in High-Energy-Density (HED) Science, High-Field and nonlinear physics [1]. Furthermore, the high intensities exceeding 1018W/cm2 allow for efficiently driving secondary sources that inherit some of the properties of the laser pulse, e.g. pulse duration, spatial and/or divergence characteristics. In the intervening decades since that first PW laser, single-shot proof-of-principle experiments have been successful in demonstrating new high-intensity laser-matter interactions and subsequent secondary particle and photon sources. These secondary sources include generation and acceleration of charged-particle (electron, proton, ion) and neutron beams, and x-ray and gamma-ray sources, generation of radioisotopes for positron emission tomography (PET), targeted cancer therapy, medical imaging, and the transmutation of radioactive waste [2, 3]. Each of these promising applications requires lasers with peak power of hundreds of terawatt (TW) to petawatt (PW) and with average power of tens to hundreds of kW to achieve the required secondary source flux.

Overview of progress in construction and testing of the laser systems of ELI-Beamlines, accomplished since 2015, is presented. Good progress has been achieved in construction of all four lasers based largely on the technology of diode-pumped solid state lasers (DPSSL). The first part of the L1 laser, designed to provide 200 mJ

We have demonstrated the world's highest average power, fully diode-pumped, petawatt-class peak power laser, the High-repetition-rate Advanced Petawatt Laser System (HAPLS) [1-3]. These first commissioning results at 16J (stretched) at 3%Hz fully validate projected performance of 30J/30fs (>1PW) at 10Hz. The laser has been operated at this intermediate level at Lawrence Livermore National Laboratory to demonstrate integrated performance of all subsystems and provide benchmarking data to laser performance models before further increasing energy and peak power. Data was obtained during multiple campaigns, exceeding several hours of run time, and a snapshot of 60min of data is shown in Fig. 1. The average pump laser 1ω (1053nm) energy was 97J with an rms stability of 0.7%, 2ω (527nm) energy at the Ti:sapphire power amplifier was 62J, and the average stretched short pulse energy was 16J. A full-aperture diagnostic suite allows simultaneous, single-shot measurement of energy, spectrum, beam quality, and pulse duration at full repetition rate. Single-shot SPIDER retrieved pulse shapes (Fig. 1 inset) with an average pulse duration over 12000 consecutive shots of 28.6fs (rms=1.4fs). The mean pulse duration is consistent with the measured spectral bandwidth and is ∼1.2× the transform limit. All results shown are raw data without filtering or averaging, demonstrating the exceptional pulse characteristics, repeatability, and stability of the entire laser system.

The HAPLS laser system has been commissioned to its first integrated performance milestone, delivering laser pulses with 16J sub-30fs duration at a 3⅓Hz repetition rate. This first all-diode-pumped petawatt-class laser offers the average powers required for secondary source applications.

Phase 1 performance ramping of the HAPLS pump laser, a high-energy DPSSL based on Nd:glass, successfully produced 70J at 1053nm from a single aperture and 39J at 527nm using LBO frequency converter running at 3.3Hz repetition rate.

Initial performance ramping of the HAPLS pump laser, a high-energy DPSSL based on Nd:glass, produced 70J at 1053nm from a single aperture and 39J at 527nm using LBO frequency converter all at 3.3Hz repetition rate.

This paper presents our conceptual design for laser drivers used in Laser Inertial Fusion Energy (LIFE) power plants. Although we have used only modest extensions of existing laser technology to en...

A high average power diode pumped solid state laser is used to pump large aperture Ti:sapphire enabling high average power chirped pulse amplification. After compression, over a petawatt of peak power will be used to generate fusion ions and neutrons for materials testing of first wall and final optics candidates.

Hundred-joule, kilowatt-class lasers based on diode-pumped solid-state technologies, are being developed worldwide for laser-plasma interactions and as prototypes for fusion energy drivers. The goal of the Mercury Laser Project is to develop key technologies within an architectural framework that demonstrates basic building blocks for scaling to larger multi-kilojoule systems for inertial fusion energy (IFE) applications. Mercury has requirements that include: scalability to IFE beamlines, 10 Hz repetition rate, high efficiency, and 10 9 shot reliability. The Mercury laser has operated continuously for several hours at 55 J and 10 Hz with fourteen 4 x 6 cm 2 ytterbium doped strontium fluoroapatite amplifier slabs pumped by eight 100 kW diode arrays. A portion of the output 1047 nm was converted to 523 nm at 160 W average power with 73% conversion efficiency using yttrium calcium oxy-borate (YCOB).

Industrial and Scientific High Energy Laser Systems with output energies in the Joule to Megajoule range typically rely on flash lamps to energize the gain media. Especially in rep rated laser systems the advantage of low capital cost per lamp is outweighed by many disadvantages, such as low pump efficiency, heating of the gain medium, frequent maintenance requirement, significant capital cost for its pulsed power system, and laser performance stability. Diode Pumped Solid State Laser (DPSSL) systems represent a viable alternative. In this paper we will present an efficient, integrated power conditioning system developed for the High-Repetition-Rate Advanced Petawatt Laser System (HAPLS) that is being developed by LLNL for deployment in the international user facility Extreme Light Infrastructure Beamlines (ELI-Beamlines) in Czech Republic [1]. The High Energy Pump Laser of HAPLS is energized by 4 High Peak Power Laser Diode Arrays with total peak power of 3.2 MW that were developed by Lasertel and LLNL. The diode arrays deliver ∼1kJ at repetition rate 10Hz. Each diode array is comprised of 40 individual diode tiles where every tile generates >20 kilowatts of peak power. Each tile is driven by a single pulser that contains its own energy storage, control and high current drive circuitry. As part of the HAPLS laser the pulsers are operated at approximately 520A, a pulse width of 300μs at 10Hz. In another LLNL laser system basically identical pulsers are operated at 315A, 300us at 120Hz. The pulsers were designed to be operated in a support frame called a pulser crate. Each crate is designed to hold up to 45 pulsers in a volume similar to a desktop computer. Communication with the pulsers is by means of a one-way digital optical link which greatly simplifies the internal wiring. Each crate contains a “Brain Box” which in turn contains the front end processor (FEP), machine safety system (MSS) and energy storage dump subsystems. Providing flexibility and system balancing capability each pulser can be tailored to the diode tile: it has an internal Arbitrary Waveform Generator (AWG) on board that controls the shape of the diode current pulse. The AWG can vary the pulse shape in any combination of programmable increments with resolutions 1A and 1μs up to maximums of 1kA and 350μs. Under command of the crate controller each pulser can create its own distinct waveform and deliver that waveform when triggered.

We report on the operation of the Mercury laser with fourteen 4 × 6 cm 2 Yb:S-FAP amplifier slabs pumped by eight 100 kW peak power diode arrays. The system was continuously run at 55 J and 10 Hz for several hours, (2 × 10 5 cumulative shots) with over 80% of the energy in a 6 times diffraction limited spot at 1.047 μm. Improved optical quality was achieved in Yb:S-FAP amplifiers with magneto-rheological finishing, a deterministic polishing method. In addition, average power frequency conversion employing YCOB was demonstrated at 50% conversion efficiency or 22.6 J at 10 Hz.

Operation of the Mercury laser with two amplifiers has yielded 30 Joules at 1 Hz and 12 Joules at 10 Hz with over 8x10{sup 4} shots on the system. Static distortions in the Yb:S-FAP amplifiers were corrected by a magneto-rheological finishing technique.

Hepatozoon polytopis, described from Coluber constrictor priapus from Palm Beach County, Florida, has short, usually broad gamonts 12.8 x 4.6 microm (10.0-15.0 x 3.5-6.0), with LW 58.5 microm2 (42-84) and L/W 2.84 (1.8-3.7). Nuclei commonly extend into first quarter of gamont (45%), are always present in second quarter, and seldom in third quarter (11%), with dimensions 4.5 x 3.4 (3.0-6.0 x 2.5-4.5) and LW 15.1 (10.0-24.0). Spherical to ovoid oocysts, 122.1 x 104.9 (62-240 x 57-190), with L/W 1.17 (1.0-1.9), contain 31.3 (3-103) sporocysts. Spherical to ovoid sporocysts, 38.0 x 33.9 (28-73 x 25-58), with LW 1,325.1 (756-4,168) and L/W 1.12 (1.0-1.4), contain 42.9 (22-64) sporozoites. Thamnophis sauritus sackenii from Palm Beach County is infected also by H. polytopis, as indicated from similar gamont dimensions and verified by isolation of an identical haplotype of the 18S ribosomal RNA gene from both host species.

Hepatozoon guttata n. sp. is described from the corn snake (Elaphe guttata guttata) from south Florida. Gamonts average 14.6 x 4.6 (13-17 x 3.5-6) and are not recurved, with nucleus situated in the second quarter of the gamont. Erythrocyte cytoplasm rarely appears partially dehemoglobinized. The infected cells are usually distorted and are longer than the uninfected erythrocytes but do not differ in width; nuclei are smaller in length and width than those of uninfected cells. Sporogony in Aedes aegypti occurs within the head and the thorax but rarely in the abdomen. Oocysts are spherical to usually ovoid, 87.2 x 75.9 (45-155 x 40-152.5) and contain on average 7.1 (2-32) sporocysts. Sporocysts are spherical to ovoid, 34.8 x 31.0 (20-55 x 17.5-47.5), with 45.7 (14-89) sporozoites contained within. The pigmy rattlesnake (Sistrurus miliarius barbouri) in south Florida is parasitized by H. sistruri n. sp. Gamonts average 14.1 x 5.6 (12.6-15.8 x 4.7-6.3) in breadth and are not recurved, with the nucleus always situated in the second quarter of the gamont commonly at the midbody. Erythrocyte cytoplasm is not dehemoglobinized. The infected cells are always distorted and similar in length to the uninfected cells but with greater width and enlarged nuclei. Sporogony in A. aegypti occurs within head, thorax, and abdomen. Oocysts are spherical to usually ovoid, 163.6 x 154.7 (92-245 x 82-240) and contain 27.4 (12-42) sporocysts. Sporocysts are round to usually ovoid, 39.7 x 33.5 (25-50 x 20-50), with 45.7 (19-70) sporozoites.

The specific diagnosis of babesiosis, which is caused by the piroplasm Babesia microti, is made by microscopic identification of the organism in Giemsa-stained thin blood smears, detection of babesial antibody in acute-and convalescent-phase sera, or identification of the organism following the injection of patient blood into laboratory animals. Although rapid diagnosis can be made with thin blood smears, parasites are often not visualized early in the course of infection. PCR is a new, rapid diagnostic technique for the detection of Babesia spp. that has not yet been systematically evaluated. We conducted a blinded study of the sensitivity, specificity, and reproducibility of the PCR-based test with patients with babesiosis and a group of asymptomatic subjects residing in a region in southern New England where babesiosis is enzootic. Among 19 patients with recent babesial illness, we found that PCR was as sensitive and specific as the use of Giemsa-stained blood smears and inoculation of hamsters. Among asymptomatic subjects, the PCR result was positive for 3 persons with recent babesial infection and was negative for 41 persons without previous babesial infection. We conclude that the B. microti PCR procedure is sufficiently sensitive, specific, and reproducible for use in the diagnosis of acute babesiosis.

This year fusion ignition and gain are expected on the National Ignition Facility at LLNL. The pathway to inertial fusion energy begins by addressing high average power operation of the diode pumped solid state laser system, target chamber, target injection and tracking, target mass production, blanket, and the balance of plant. To meet efficiency requirements, the power conditioning for the laser diodes must be compact and efficient. A diode pulser has been designed to meet these specifications, operate efficiently, and provide a means to minimizing cost and size for the estimated 4.4 million pulsers needed for a power plant.

Laser systems deployed in Inertial Fusion Energy power plants will usher in space qualified laser engineering and materials on a massive scale. Understanding subsystem efficiencies and component Mean Time Between Failure (MTBF) are critical for success.

We have commissioned a turnkey 500 mJ, 10 Hz front end laser. The system delivers temporally and spectrally tailored pulses to correct signal distortions within itself or subsequent amplifiers from single longitudinal mode to 250 GHz RF bandwidth.

The Mercury laser will be used to pump a high average power Ti:sapphire chirped pulse amplifier which will produce a compressed peak power >1 petawatt at 10 Hz.

We have produced over 500 mJ using a hybrid fiber-based master-oscillator system coupled with a Yb:S-FAP power amplifier. This system is designed with spatial, temporal, and spectral sculpting enabling broadband amplification correctable for gain narrowing.

The Mercury laser project is part of a national inertial fusion energy program in which four driver technologies are being considered including solid-state lasers, krypton fluoride gas lasers, Z-Pinch and heavy ions. Mercury's operational goals of 100 J, 10 Hz, 10% efficiency in a 5 times diffraction limited spot will demonstrate the critical technologies required for scaling the system to the multi-kilojoule level. Five one hour runs were conducted to assess system stability and reliability; energy fluctuations during the 55 J operations showed a 0.6% rms deviation. Current beam quality during average power operation is approximately 10 times diffraction limited. In the future, active wavefront control, and corrector plates for steady state thermal distortions will be implemented to achieve the 5 times diffraction limited spot.

Mechanical and Aeronautical Engineering, University of California, Davis, CA 95616 USA Abstract: Operation of the Mercury laser with one of two amplifiers activated has yielded 31.6 Joules at 0.1 Hz and 20.6 Joules at 10 Hz. Correction of static distortions in the amplifier was accomplished using a conjugate phase optic.

The scope of the Mercury Laser project encompasses the research, development, and engineering required to build a new generation of diode-pumped solid-state lasers for Inertial Confinement Fusion (ICF). The Mercury Laser will be the first integrated demonstration of laser diodes, crystals, and gas cooling within a scalable laser architecture. This report is intended to summarize the progress accomplished during the first three years of the project. Due to the technological challenges associated with production of 900 nm diode-bars, heatsinks, and high optical-quality Yb:S-FAP crystals, the initial focus of the project was primarily centered on the R&D in these three areas. During the third year of the project, the R&D continued in parallel with the development of computer codes, partial activation of the laser, component testing, and code validation where appropriate.

We report on the progress in developing and building the Mercury laser system as the first in a series of a new generation of diode- pumped solid-state Inertial Confinement Fusion (ICF) lasers at Lawrence Livermore National Laboratory (LLNL). Mercury will be the first integrated demonstration of a scalable laser architecture compatible with advanced high energy density (HED) physics applications. Primary performance goals include 10% efficiencies at 10 Hz and a 1-10 ns pulse with 1 omega energies of 100 J and with 2 omega/3 omega frequency conversion.

The superior colliculus (SC) has an established role in the sensory guidance of motor commands required to orient an animal towards novel stimuli. In addition to the representations of visual, auditory, and somatosensory stimuli, the SC also contains a large population of nociceptive neurones. The purpose of the present investigation was to see if nociceptive neurones in the SC can be characterised with c-fos immunohistochemistry as a prelude to establishing anatomical connectivity with specific target regions in the brainstem. To ensure comparability with previous electrophysiological investigations, the present study was conducted in animals anaesthetised with urethane. A series of independent issue relating to basic aspects of experimental protocol were investigated. The principal findings were: (i) Despite minimising the exposure of animals to extraneous stimuli, basal levels of immunostaining were observed. (ii) Urethane anaesthesia induced an increase in Fos-like immunoreactivity (FLI) over the basal condition. (iii) No additional labelling was induced by non-noxious tactile stimulation of the hindpaw. (iv) Unilateral noxious mechanical stimulation elicited a reliable increase in FLI over all control conditions. (v) This increase in FLI was expressed bilaterally and restricted largely to the intermediate white layer. (vi) The induction of FLI was related to noxious stimulation intensity. (vii) No reliable differences in the spatial topography of FLI expression were observed when unilateral noxious mechanical stimulation was administered to the face or hind foot. (vii) A higher level of urethane anaesthesia had a generally suppressive effect on FLI expression. (ix) There were no differences in the distribution of FLI induced by noxious mechanical or noxious chemical stimulation. (x) The increase in FLI induced by noxious pinch was abolished by a naloxone reversible pre-treatment with morphine. These data confirm that c-fos immunohistochemistry can be used to characterise nociceptive cells in the rat superior colliculus, and generally complement recent electrophysiological data. The identification of nociceptive cells in the stratum album intermediale, the source of collicular input to regions of the contralateral brainstem involved in orienting, suggests the SC may play a significant role in the localisation of pain.

We present the results of performance modeling of diode-pumped solid state laser beamlines designed for use in Laser Inertial Fusion Energy (LIFE) power plants. Our modeling quantifies the efficiency increases that can be obtained by increasing peak diode power and reducing pump-pulse duration, to reduce decay losses. At the same efficiency, beamlines that use laser slabs of Yb:YAG or Yb:S-FAP require lower diode power than beamlines that use laser slabs of Nd:phosphate glass, since Yb:YAG and Yb:S-FAP have longer storage lifetimes. Beamlines using Yb:YAG attain their highest efficiency at a temperature of about 200K. Beamlines using Nd:phosphate glass or Yb:S-FAP attain high efficiency at or near room temperature.

The x-ray streak camera and x-ray framing camera for the National Ignition Facility were redesigned to improve electromagnetic pulse hardening, protect high voltage circuits from pressure transients, and maximize the use of common parts and operational software. Both instruments use the same PC104 based controller, interface, power supply, charge coupled device camera, protective hermetically sealed housing, and mechanical interfaces. Communication is over fiber optics with identical facility hardware for both instruments. Each has three triggers that can be either fiber optic or coax. High voltage protection consists of a vacuum sensor to enable the high voltage and pulsed microchannel plate phosphor voltage. In the streak camera, the high voltage is removed after the sweep. Both rely on the hardened aluminum box and a custom power supply to reduce electromagnetic pulse/electromagnetic interference (EMP/EMI) getting into the electronics. In addition, the streak camera has an EMP/EMI shield enclosing the front of the streak tube.

A LIFE laser driver needs to be designed and operated which meets the rigorous requirements of the NIF laser system while operating at high average power, and operate for a lifetime of >30 years. Ignition on NIF will serve to demonstrate laser driver functionality, operation of the Mercury laser system at LLNL demonstrates the ability of a diode-pumped solid-state laser to run at high average power, but the operational lifetime >30 yrs remains to be proven. A Laser Technology test Facility (LTF) has been designed to specifically address this issue. The LTF is a 100-Hz diode-pumped solid-state laser system intended for accelerated testing of the diodes, gain media, optics, frequency converters and final optics, providing system statistics for billion shot class tests. These statistics will be utilized for material and technology development as well as economic and reliability models for LIFE laser drivers.

On March 7, 1978, a successful field test of the recovery of oil from under river ice was conducted on the North Saskatchewan River in Alberta, Canada. The ice was 28 inches (70 cm) thick, the water depth ranged from 1.5 to 7.9 ft (0.5 to 2.4 m) and the average water current was 1.3 ft/second (40 cm/sec). Dyed vegetable oil and crude oil were released under the ice upstream of a recovery slot which was 4 ft (1.2 m) wide, 400 ft (122 m) long, and placed at an angle of 30 degrees to the current. Almost all the vegetable and crude oil that was released under the river ice was intercepted by the slot and diverted to the slower current at the downstream end of the slot where it was readily recovered with a specially-constructed weir skimmer. From experiments in small 4 ft by 4 ft (1.2 m by 1.2 m) slots cut in the ice, it was determined that a slot would hold about a 5 inch (12 cm) layer of oil on the water surface for an ice thickness of 28 inches (70 cm) and an average current of 1.6 ft/sec (50 cm/s). A trenching machine (Ditch Witch) proved effective for cutting the ice. Ice blocks about 3 ft by 4 ft (1 m by 1.3 m) were formed and pushed along the slot to the river bank. There, each ice block was lifted with a mobile crane by means of a cable and T-bar inserted through a 6 inch (15 cm) diameter hole drilled in the centre of the block. The load bearing capacity of the ice was critical in determining the type and size of equipment that could operate safely on the ice. The project was conducted by the Prairie Region Oil Spill Containment and Recovery Advisory Committee and was financed by the Canadian Petroleum Association, Environment Canada, and the Petroleum Association for the Conservation of the Canadian Environment.

The site of the Orwell bridge is described and an explanation is given of how the planning of the construction was developed to suit the structure which comprises on one bank a viaduct built over dry land, a central main span section over the navigation channel and a further viaduct which had to be built over the mud flats of the intertidal range. A tight programme of three years was set for completion and this was further complicated by the requirement to have the abutments and end spans completed at an early stage in the contract to allow others to construct the approach embankments at either end of the bridge. The key to the contractor's successful tender was Dutch ingenuity in planning the temporary works in the river and this is described. Information is given on the methods of construction adopted for the foundations and substructure which comprised cast-in-place bored piles, heavily reinforced concrete pile caps and slender twin-stalk piers rising to a height of 40 M. The construction of the twin prestressed concrete box girder deck is also described. see also TRIS abstract No. 382112. (Author/TRRL)

This paper presents results of a taxonomic investigation of the family Syrphidae of the order Diptera in Puerto Rico. A total of 58 species included in 11 genera are presently recorded as a result of synonymy, new records, and descriptions of the following four new species: Baccha ( Baccha ) martorelli, Baccha ( Ocyptamus ) medina, Baccha ( Baccha ) neoparvicornis and Baccha ( Ocyptamus ) vockerothi . Keys are given for the identification of the reported genera and for most of the recorded species.

Approximately 50% of the wheat kernels threshed from a commercial combine and from a small experimental unit were fractured as compared with approximately 1% in hand-threshed samples. There were significant differences in susceptibility to fracturing among 6 varieties and between samples from 2 locations in both the machine- and hand-threshed samples. However, other factors such as shape of kernel, ease of threshing, and protein content of the kernels could account for these differences. The rusty grain beetle, Cryptolestes ferrugineus (Stephens), was unable to invade sound kernels of several varieties of wheat maintained at 16% moisture, but could infest kernels with damaged grain coats. This species preferred the germ. It can infest fractured wheat in the absence of a primary insect invader.

A diagnostic key and illustrations of male genitalia are presented for the identification of the 27 species of Eristalis known from America north of Mexico. Synonymy and distributional records are updated. A complete description of E. beltrami Telford is given for the first time. A parallotype is designated for E. texanus Hull, a lectotype and allolectotype for E. pilosus Loew, and a lectotype for E. obscurus Loew.

When diazinon sprays and dusts were applied to wheat at 1, 2.5, and 5 ppm and stored for 168 days in open jars at ambient room temperature, the toxicity of the treated grain to insects was markedly reduced after 7 days. Granary weevil adults, Sitophilus granaries (L.), were considerably more resistant than the red flour beetle, Tribolium castaneum (Herbst), or the saw-toothed grain beetle, Oryzaephilus surinamensis (L.). The red flour beetle was most susceptible. The dusts were more effective than the sprays and the efficacy of both was reduced more in the 13.4±0.5% moisture wheat as compared with the wheat maintained at 10.6±0.6%. Chemical estimations indicated considerable loss of dizainon immediately after treatment. The dusts generally persisted in greater amounts than the sprays. The residues from wheat within 168 days varied from 0.29 ppm from samples receiving an initial application of 1 ppm to 2.47 ppm from an initial treatment of 5 ppm. Quality evaluations on milling, baking, and flavor indicated no untoward effects when wheat was treated with 8 ppm diazinon and evaluated at a maximum of 9 days later.

I was indeed pleased and flattered to be asked to give this address. I have always maintained a keen interest in history—particularly the events pertinent to Entomology. To prepare this paper was no chore—it was a joy. I become somewhat vexed at times when youngsters do not share my enthusiasm for history. So often doctoral candidates know virtually nothing of the early developments of the biological sciences and less about their own specialty.