Fine Screen Research Articles

Parasitism by Trichogramma spp. (Hymenoptera: Trichogrammatidae) in Relation to Nantucket Pine Tip Moth (Lepidoptera: Tortricidae) Egg Density and Location

Patterns of parasitism by Trichogramma spp. relative to density and location of Nantucket pine tip moth, Rhyacionia frustrana (Comstock), eggs were examined during 1994 in a 13-ha, 2-yr-old Pinus taeda L. plantation in northeastern Georgia. Egg densities were adjusted by temporarily enclosing trees in fine mesh screen cages and introducing different numbers of tip moths. After exposing eggs to naturally occurring parasitoids, all shoots were removed, and eggs were counted and evaluated for parasitism. Tip moth egg densities ranged from 203 to 2,579 per tree for the spring generation, and from 1 to 89 per tree for the summer generation. Tip moths deposited significantly greater numbers of eggs on needles than shoots on high-versus low-egg-density trees. Overall parasitism rates were 37.2 and 43.3% for spring- and summer-generation eggs, respectively. Parasitism was density independent at the whole-tree level in both generations, but spring-generation parasitism was strongly inversely density dependent in the top whorl. Numbers of eggs per needle fascicle ranged from 1 to 15 for spring-generation trees. Actual numbers of parasitized eggs per discovered fascicle (one on which parasitism occurred) increased with egg density, but the percentage of parasitized eggs decreased. Egg density had no effect on fascicle discovery. These factors produced an inversely density-dependent relationship between egg parasitism and density at the fascicle level. Eggs located on shoots suffered significantly greater parasitism rates than those on needles. Implications of these results are discussed.

The effect of selective sampling on mapping quantitative trait loci

Sib pairs were selectively sampled for extreme concordance or discordance for the quantitative trait Q1, a simulated phenotype (GAW10). Two selective sampling criteria were used (SC1 and SC2), and results for these were compared to linkage analyses using all pairs (ALL). In total 773 sib pairs were available, which reduced to an average of 59.7 pairs under SC1, and 134.1 pairs under SC2. Whole genome screens were performed on 10 different data replicates for each selection criterion (ALL, SC1, and SC2). Fine screens were then performed over regions which indicated at least suggestive linkage, and these regions were also fine screened in an independent data replicate in an attempt to repeat any areas found. The results for the coarse genome screens were similar under each of the criteria, although in general lower maxima and slightly more erratic lods were found under the stricter selection methods. The correct region on chromosome 5 (responsible for approximately 22% of the variance of Q1) was detected (p < 0.0001) in 6/10 of the data replicates using ALL, and 4/10 using SC1 and SC2. The second quantitative trait locus (QTL) on chromosome 8 (only 0.5% of the variance of Q1) was detected in only a single data replicate using SC1. False positive rates were similar for each criterion, whereas power decreased using selective sampling compared to ALL, although this was probably due to an insufficient initial sample size. © 1997 Wiley-Liss, Inc.

The effect of selective sampling on mapping quantitative trait loci.

Sib pairs were selectively sampled for extreme concordance or discordance for the quantitative trait Q1, a simulated phenotype (GAW10). Two selective sampling criteria were used (SC1 and SC2), and results for these were compared to linkage analyses using all pairs (ALL). In total 773 sib pairs were available, which reduced to an average of 59.7 pairs under SC1, and 134.1 pairs under SC2. Whole genome screens were performed on 10 different data replicates for each selection criterion (ALL, SC1, and SC2). Fine screens were then performed over regions which indicated at least suggestive linkage, and these regions were also fine screened in an independent data replicate in an attempt to repeat any areas found. The results for the coarse genome screens were similar under each of the criteria, although in general lower maxima and slightly more erratic lods were found under the stricter selection methods. The correct region on chromosome 5 (responsible for approximately 22% of the variance of Q1) was detected (p < 0.0001) in 6/10 of the data replicates using ALL, and 4/10 using SC1 and SC2. The second quantitative trait locus (QTL) on chromosome 8 (only 0.5% of the variance of Q1) was detected in only a single data replicate using SC1. False positive rates were similar for each criterion, whereas power decreased using selective sampling compared to ALL, although this was probably due to an insufficient initial sample size.

Manufacturing Technology of High Brightness DIP from ONP

Recently, Hight Brightness DIP from Old Newsptint (ONP) is used for printing paper, PPC, information paper, and LWC paper. Required Quality of DIP is high brightness (over 70%), fewer residual inks and fewer contaminants.This paper describes Manufacturing Technology of High Brightness DIP from ONP. In principle, General DIP plant (brightness 55-60%) has four processes, i. e., pulping, screening, deinking, and bleaching process. In the case of Manufacturing High Brightness DIP plant, in principle, this plant is almost same as General DIP plant. But this plant needs more effective equipment and more effective treatment.1. Pulping:Contaminants are early removed by pulper screen or drum pulper.2. Screening:Coarse and Fine screen are used, Slot size of fine screen is 0.15mm.3. Deinking:For detachment of ink from fibers, Mechanical treatment (Dispersing System) and Chemical treatment (Aging System) are applied. For removal of ink particles, effective flotation and washing system are applied.4. Bleaching:For Brightness 55-60%, generally, Hydrogen peroxide is used. For High Brightness over 70%, at first stage, Hydrogen peroxide is used. Then second stage, Hydrogen peroxide or Thiourea dioxide (FAS) is used.

A simple rearing chamber for lotic insect larvae

An effective rearing chamber for aquatic insects can be made from inexpensive commercially available products. An angled air line is attached to a round 400 ml Rubbermaid® dish with a snap-on lid to create a circular flow with bubbles. The lid included with the dish can be modified to accept a tube with fine mesh screen at one end for capturing emerging adults. This chamber is a reliable and effective technique for studying larval behavior and obtaining adults for species identification.

How sieve mesh size affects sample estimates of estuarine benthic macrofauna

The way mesh size influences the reliability of density and biomass estimates in macrofauna sampling was investigated for a benthic community in the shallow, upper reaches of a small, temperate estuary. Macrofauna was separated from the sediment with sieves of 0.25, 0.5 and 1.0 mm mesh aperture size and the performance of each gear type in terms of retention efficiency evaluated. The 0.25 mm sieve sampled all macrofauna adequately, but only 55% of all individuals were, on average, retained by the 0.5 mm mesh and a mere 8% by the 1.0 mm mesh. Mean retention efficiency for total biomass was 86% for the 0.5 mm and 49% for the 1.0 mm screen, respectively. Undersampling by bigger mesh sizes was most severe for juveniles and small species, resulting in biased interpretation of apparent community structure. Because population densities obtained by the two bigger screens were not only markedly less accurate (i.e., biased lower counts), but also less precise (i.e., higher standard errors), the use of 0.5 mm and 1.0 mm mesh sizes significantly increased replication levels. Consequently, for this specific habitat and community, sampling schemes which employ a 1.0 mm mesh were considerably more expensive than designs using finer screens. No single sampling design will perform optimally in each permutation of habitat and community, but our data emphasise the need for the stringent assessment of sampling errors and caution against the uncritical use of mesh sizes greater than 0.25 mm in estimating population densities of estuarine macrobenthos.

Cyclone-type fine screen device

Cyclone-type fine screen device

Fine screeningSolanum (potato) germplasm accessions for resistance to Colorado potato beetle

This study was conducted to investigate the utility of systematic screening at the genotype level withinSolanum accessions highly resistant to the Colorado potato beetle. Evaluations of clonally replicated genotypes showed that most accessions reported to be uniform when screened as populations contained small but significant variation among genotypes for resistance to oviposition, larvae, and defoliation, differences for numbers of larvae being most common. Adult counts and percentage defoliation were not as useful in evaluating among-genotype variability in beetle resistance. Genotypes ofS. pinnatisectum WRF 343 andS. tarijense PI 473227 were the most uniformly and highly resistant to Colorado potato beetle. Genotypes of S.berthaultii PI 473331,S. chacoense PI 473405, andS. tarijense PI 473336 were moderately to highly resistant, and genotypes ofS. bukasovii PI 473494 andS. canasense PI 230511 were uniformly susceptible to Colorado potato beetle. Nonparametric correlation analyses indicated that number of egg masses, small larvae, large larvae, and defoliation scores were positively correlated, negatively correlated, or not correlated, depending on the species. One generation of selection attempting to segregate resistance and susceptibility in nearly uniform and highly resistantS. pinnatisectum WRF 343 resulted in “divergent” populations that could not be distinguished from each other or the base population. Thus, through genotype (“fine”) screening and selection, we showed that some existing populations are virtually pure for extreme resistance. Use of individuals from such families would make screening breeding populations more efficient, and reduce the risk of losing resistance genes that have non-dominant effects. Fine screening, recurrent selection, and maintenance of such elite populations is recommended as an extension of population-based evaluation usually done by genebanks.

Interaction of laser ablation plasma plume with grid screens

Optical emission spectroscopy and charge collector time-of-flight measurements have been used to study interaction of laser ablation carbon plasma with grid screens in vacuum under conditions typical for pulsed laser deposition of thin diamondlike films. The effect of velocity distribution transformation of the ion flow has been observed and studied in a variety of experimental conditions. Our results indicate that the observed phenomenon is due to interaction of two plasma flows, the initial expanding one and the fraction of that flow scattered by the substrate or the screen. Three typical modes of velocity distribution function transformation have been observed depending on the plasma density: linear attenuation of the flow density, nonlinear attenuation of the slow ‘‘tail’’ of the velocity distribution function, and nonlinear transformation of the entire velocity spectrum. The latter regime occurs when plasma is throttling through the fine mesh screen. Our observations show that the reported phenomenon may substantially affect deposited film properties.

An improved gastric lavage device for removing stomach contents from live fish

An improved gastric lavage apparatus was developed to remove stomach contents of live fish. A polypropylene pipette and polyethylene tubing were connected to a compression sprayer by quick-disconnect fittings. This enabled the operator to choose different sizes of pipettes depending on the size of the fish being sampled. Water was flushed into the stomach of the fish forcing the stomach contents out through the esophagus. Stomach contents were deposited in a measuring trough and collected on fine screening. The apparatus is inexpensive to construct and is effective in removing all of the stomach contents from fish, while causing no mortality. It is portable and contains no breakable parts, making it well suited for field work.

Case studies on preliminary treatment facilities at marine outfalls

As with many coastal discharges, the search for a suitable primary treatment system has long been accepted as a first stage treatment of both municipal and industrial wastewater. Over the last decade, milliscreening has almost become the best alternative method among the conventional systems applicable to marine outfall treatment. This paper, summarizes three case studies using milliscreening equipment with variable bar spacings on treatment facilities at marine outfalls. The best solution was achieved at Poverty Bay in New Zealand where the bar spacing was 1 mm. The other two applications were attempted in United Kingdom. The milliscreens of 10 mm at Tonyrefail and 5 mm at Wooler were not able to meet the required performance. In regard of these studies, it is recommended that finer screens with bar spacing of less than 5 mm are likely to provide adequate performance when used to screen marine outfalls.

Case studies on preliminary treatment facilities at marine outfalls

As with many coastal discharges, the search for a suitable primary treatment system has long been accepted as a first stage treatment of both municipal and industrial wastewater. Over the last decade, milliscreening has almost become the best alternative method among the conventional systems applicable to marine outfall treatment. This paper, summarizes three case studies using milliscreening equipment with variable bar spacings on treatment facilities at marine outfalls. The best solution was achieved at Poverty Bay in New Zealand where the bar spacing was 1 mm. The other two applications were attempted in United Kingdom. The milliscreens of 10 mm at Tonyrefail and 5 mm at Wooler were not able to meet the required performance. In regard of these studies, it is recommended that finer screens with bar spacing of less than 5 mm are likely to provide adequate performance when used to screen marine outfalls.

中性脱墨の特長と今後の課題 マイクロフローテーション等による問題解決への取り組み

Deinking Technology has been rapidly improved specially in the field of hardware, such as High Consistency Pulping, Fine Slot Screening, Dispersing, and Post-Flotation etc.. However Almost all of the deinking process are still operated under Alkali base, which is still common technology for the deinking.In order to improve sticky problems, Aikawa has recommended two loops deinking system which consists of Neutral, Room Temperature loop for the first half of the system and Alkali, High Temperature loop for the latter half of the system since several years ago. In Europe, very recently, the first Neutral deinging system was started in an actual paper mill, which shows some advantages to protect the pollution of environment and to save production cost in spite of some disadvantages. This paper shows these advantages and problems for the Neutral Deinking Technology.

Flight performance of the SHOOT liquid acquisition devices

The Superfluid Helium On-Orbit Transfer (SHOOT) Flight Demonstration, launched on STS-57 in June 1993, demonstrated the technology required for the management and transfer of superfluid helium in low gravity, and was the first orbital experiment using liquid acquisition systems with cryogens. Its primary experimental objective was to test the performance of two different liquid acquisition devices (LADs) which use surface tension forces to gather the liquid and feed it to the superfluid pumps. One system consists of c-channels whose open sides are covered by fine mesh screens which face the tank walls. The other consists of a series of Mylar/TM vanes which extend radially from the centre of the tank. Several superfluid transfers were performed during relatively quiescent periods and during two transfers adverse orbiter accelerations of 0.034 and 0.069 m s −2 (3.5 × 10 −3 and 7.0 × 10 −3 g) were generated to move liquid away from the pumps to test the ability of each LAD to work against relatively large hydrostatic heads. Discrete liquid/vapour discriminators placed strategically within the tanks were used to detect failure of the LADs to supply liquid to the pumps. One goal was to test whether, if such a failure occurs, the transfer process can spontaneously recover without operator intervention. Overall performance of both LADs during transfers with and without adverse accelerations is presented.

Reduction in size and unsteadiness of VTOL ground vortices by ground fences

A ground vortex, produced when a jet impinges on the ground in the presence of cross flow, is encountered by V/STOL aircraft hovering near the ground and is known to be hazardous to the aircraft. The objective of this research was to identify a ground-based technique by which both the mean size and fluctuation in size of the ground vortex could be reduced. A simple passive method was identified and examined in the laboratory. Specifically, one or two fine wire mesh screens (ground fences) bent in a horseshoe shape and located on the ground in front of the jet impingement point proved to be very effective. The ground fences work by decreasing the momentum of the upstream-traveling wall jet, effectively causing a higher freestream-to-jet velocity ratio (V(sub infinity)/V(sub j)) and thus, a ground vortex smaller in size and unsteadiness. At(V(sub infinity)/V(sub j)) = 0.15, the addition of a single ground fence resulted in a 70 percent reduction in mean size of the ground vortex. With two ground fences, the mean size decreased by about 85 percent. Fluctuations in size decreased nearly in proportion to the mean size, for both the single and double fence configurations. These results were consistent over a wide range of jet Reynolds number (10(exp 4) less than Re(sub jet) less than 10(exp 5)); further development and full-scale Reynolds number testing are required, however, to determine if this technique can be made practical for the case of actual VTOL aircraft.

Evaluation of cokes as filter aids in direct coal liquefaction

One of the major problems experienced in the development of filtration for coal liquefaction has been the rapid clogging of fine metal filter screens. Tests have shown that the screens could be cleaned in situ, and the frequency of such cleaning could be reduced by using precoats. Standard diatomaceous precoats could be used, but these are expensive and their use could reduce the thermal value of the filter cake. Various carbonaceous products derived from coal and petroleum have been suggested as alternatives. 15 different samples of coke have been assessed in laboratory tests. All had a good performance in terms of low cake resistivities, screen bridging, and effected considerable protection for metal screens against clogging. When used in plant tests as a 5 mm precoat, the petroleum coke fines effected a doubling of interval between in-situ cleaning (sluicing) and was resistant to particle breakdown during slurry recycle. Coal extract coke and carbonized coal used as filter aids in plant tests also doubled the interval between in-situ cleaning, but they behaved similarly to celite in the breakdown tests, being inferior to cyclone fines in this respect. The use of carbonaceous materials as body feed leads to a marked decrease in filter-cake resistivity and, therefore, to an increased efficiency of filtration area.

The improvement of plant N acquisition from an ammonium-treated, drought-stressed soil by the fungal symbiont in arbuscular mycorrhizae

The ability of the external mycelium in arbuscular mycorrhiza for N uptake and transport was studied. The contribution of the fungal symbiont to N acquisition by plants was studied mainly under waterstressed conditions using 15N. Lettuce (Lactuca sativa L) was the host for two isolates of the arbuscular mycorrhizal fungi Glomus mosseae and G. fasciculatum. The experimental pots had two soil compartments separated by a fine mesh screen (60 μm). The root system was restricted to one of these compartments, while the fungal mycelium was able to cross the screen and colonize the soil in the hyphal compartment. A trace amount of 15NH 4 + was applied to the hyphal compartment 1 week before harvest. Under water-stressed conditions both endophytes increased the 15N enrichment of plant tissues; this was negligible in nonmycorrhizal control plants. This indicates a direct effect of arbuscular mycorrhizal fungi on N acquisition in relatively dry soils. G. mosseae had more effect on N uptake and G. fasciculatum on P uptake under the water-limited conditions tested, but both fungi improved plant biomass production relative to nonmycorrhizal plants to a similar extent.

Effectiveness of Windscreens on Modifying Airflow Around a Sprayer Boom

The effectiveness of porous shrouding on sprayer booms for the reduction of wind velocity in the vicinity of a spray nozzle was investigated. Tests were performed in a wind tunnel for air velocities ranging from 2.6 to 6.5 m/s (5.8 to 14.6 mph). Investigation was limited to airflow patterns and air velocity measured inside and behind a model boom. The relative difference in velocity changes was observed to be different as original wind velocities increased in front of the shrouds. There was approximately 10% greater wind velocity reduction inside and behind the boom covered with fine screen at the original wind velocity of 2.6 m/s (5.8 mph) than at 6.5 m/s (14.6 mph). It was noted that the shrouding material had a significant effect on wind speed reduction. At a wind velocity of 4.4 m/s (10 mph) and for 0.025 < P < 0.01 range of significance, a double layer of fine mesh caused 22 and 33% greater drop in wind velocity inside and behind the boom, respectively, than a single layer. There was a significant difference (P = 0.025) in velocity reductions in investigated areas between a sprayer boom angle of 60 and 80 covered with the same shroud. It was also noted that impermeable shielding over the entire front shroud gave results preferable to those obtained with partial impermeable shielding.

Apple, Laboratory Evaluation of Penncap M for Control of Larvae of Rblr, 1991

Abstract Redbanded leafroller (RBLR) larvae caused serious damage to fruit in Frederick County, Virginia, in 1990. In one orchard where Penncap M had been used for several years (including 1990) the problem was particularly severe and larvae from eggs laid by the overwintering generation were very abundant in the spring of 1991. Efficacy of insecticide against RBLR larvae in this orchard was questioned. Consequently, two laboratory toxicity studies were conducted. Exp. 1 was designed to evaluate relative toxicities of several pesticides currently recommended for control of RBLR. Exp. 2 was performed to determine an effective dosage of pesticides for grower use. Terminal apple shoots bearing 5 live RBLR larvae were dipped in the appropriate toxicant dilutions which had been mixed in 1 gal battery jars. There were 4 replicates of each treatment and a control. After dipping, the basal portion of the shoot was passed through a fine meshed nylon screen into water in the bottom of a styrofoam cup. The screen was taped so as to seal it to the top of the cup and served to prevent larvae from entering the water. Each of these units was then placed in a clean glass battery jar. Tops of jars were covered with fine nylon netting, held in place with a rubber band, and held at 80°F in a lighted room. Larvae were examined after 24 and 48 h and categorized as live or dead. Death was determined by the lack of any movement when the larva was probed gently with a blunt steel probe.

Histocompatibility screening by molecular techniques: use of polymerase chain reaction products and heteroduplex formation.

Novel molecular approaches have recently become available allowing improved major histocompatibility complex (MHC) matching of potential allogeneic bone marrow donors and recipients. Current cellular and serological assays are hindered by aberrant cell populations and limited reagents which only detect an individuals' phenotype. Therefore, a molecular screening protocol which discriminates at the genotypic level would be advantageous. Here we describe a two-step DNA-based approach that can be applied to large-scale screening of potential donors. A primary screen, utilizing polymerase chain reaction (PCR), reduces the potential donor population, whereas a secondary or fine resolution screen uses DNA heteroduplex analysis to determine identity or non-identity at specific loci. Heteroduplex analysis generates a DNA migration pattern that is unique for alleles at a given locus, and is more sensitive than serology in discriminating among individuals. Here we demonstrate the potential feasibility of this approach by analyzing results at one MHC locus, HLA-DQ. Since this method does not rely on typing sera or viable lymphocytes, it is not subject to the variability found in the traditional methods. In contrast to traditional methods, these molecular techniques can provide the critical information needed to select a potential bone marrow donor.