bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling magnetostrictive material for high-speed tracking
Authors: Bottauscio Oriano , Roccato Paolo E. , Zucca Mauro
Published: April 2011

This work proposes a simplified model applicable to devices based on magnetostrictive materials conceived to be implemented in the control of a micropositioner. The 1D magnetomechanical dynamic model of the active material is based on the Preisach hysteresis model and includes classical eddy currents. The model has been used in a digital signal processing procedure for the determination of the supply current tracking position. Comparisons with experiments, obtained by controlling the actual micropositioner in an open loop chain, are satisfactory.
Role of the rise rate of beam current in the microwave radiation of vircator
Authors: Li Limin , Cheng Guoxin , Zhang Le , Ji Xiang , Chang Lei , Xu Qifu , Liu Lie , Wen Jianchun , Li Chuanlu , Wan Hong
Published: April 2011

In this paper, the effect of the rise rate of beam current on the microwave radiation of a virtual cathode oscillator (vircator) is presented. Interestingly, it was observed that the rise rate of the beam current increased as the pulse shot proceeded, which is accompanied by the decrease in microwave power. By comparing the experimental results of two cathode materials (carbon fiber and stainless steel), it was found that the above behavior is independent of the cathode materials. The ion flow, induced by the repetitive action of beam electrons with the anode grid, directly affects the development of beam current. A twice-increased process of ion flow was observed, and there are two factors involved in this process, namely, the reflection of electrons between the cathode and virtual cathode and the effect of one-time bombardment of electron beam. After the irradiation of pulsed electron beam, some microprotrusions toward the cathode appeared on the anode surface, with a quasiperiodic structure. The appearance of ion flow, as the anode plasma forms, increases the beam current and enhances the beam current density. The anode plasma is generated relatively easily as the shot test proceeds, due to the aging of anode grid, which allows the possibility of the decrease in the microwave power. As the pulse shot proceeds, the changes in the rise rate of beam current are closely related to the aging process of anode surface. Therefore, the further enhancement of vircator efficiency needs to lengthen the lifetime of anode, besides the optimization of explosive emission cathodes.
Dipole-dipole interactions in the computational micromagnetism of iron (1955-2010) (invited)
Authors: Arrott Anthony S.
Published: April 2011

Basic treatment of magnetically soft ferromagnetic metals has been a long struggle during the 55 years of the MMM conferences. At the first conference, Charles Bean brought on stage a four-foot-long mechanical analog of a domain wall. Landau, twenty years earlier had shown that the wall exists to minimize the magnetostatic self-energy of the dipole moments that accompany the spins responsible for ferromagnetism, but no one could calculate the energy of the simple structure that Landau used to illustrate his conjecture. The structure itself was not adequately described. Today, computer programs use the full power of micromagnetics to properly describe the vortex structure that was hidden in Landau’s model. Vortices terminate in swirls that can be manipulated by small bias fields (mT) or currents (mA). The swirls carry external fields of 0.5 T and can oscillate (driven or freely) over distances of tens of nm in times of tenths of ns, providing new tools for scientific and technical advances on the atomic scale. That this could have been overlooked for so long is evidence of the difficulty of visualizing the consequence of what for all these years has been called the pole-avoidance principle.
Optimization of the processing parameters for building in uniaxial magnetic anisotropy in tension-annealed Fe82Ga18 rods
Authors: Jones Nicholas J. , Restorff J. B. , Wun-Fogle M. , Clark A. E.
Published: April 2011

Fast-growth rods of Fe82Ga18 were tension-annealed under various conditions to evaluate the effects of time, temperature, and stress on the induced uniaxial anisotropy. The minimum amount of stress, temperature, and time necessary for the optimal properties was determined. Samples were annealed at 600 °C for 1 h in air to improve the homogeneity of the samples before each stress anneal. These initialized samples showed 45% alignment of moments along the rod axis. Under optimized tension-annealing conditions the percentage alignment increased to as much as 94%. This increase in alignment corresponds to a decrease in internal magnetic anisotropy energy fromabout −1.6 to −3.2 kJ/m3. The optimal annealing conditions were found to be 300 °C at 50 MPa for 5 min.
Design of a LC-tuned magnetically suspended rotating gyroscope
Authors: Jin Lichuan , Zhang Huaiwu , Zhong Zhiyong
Published: April 2011

A inductor-capacitor (LC) tuned magnetically suspended rotating gyroscope prototype is designed and analyzed. High permeability ferrite cores are used for providing suspension force, and the rotation system is designed using the switched reluctance motor (SRM) principle. According to the LC-tuned principle, magnetic suspension force expression has been derived. The electromagnetic properties of the gyroscope are simulated by the Ansoft Maxwell software. And our result is expected to be able to serve as a prototype of micro-electromechanical system (MEMS) magnetically suspended rotating gyroscope in future practical applications.
Steady-state liquid sloshing in a rectangular tank with a slat-type screen in the middle: Quasilinear modal analysis and experiments
Authors: Faltinsen O. M. , Firoozkoohi R. , Timokha A. N.
Published: April 2011

Two-dimensional resonant liquid sloshing in a rectangular tank equipped with a central slat-type screen is studied theoretically and experimentally with focus on nonsmall solidity ratios of the screen (0.5≲Sn≲0.95), nonlarge number of slots (N≲50), and steady-state conditions. The tank is horizontally and harmonically excited with frequencies in a range covering the two lowest primary-excited natural sloshing resonance frequencies in the corresponding clean tank. The liquid depth is finite. Theoretical analysis is based on the multimodal method with linear free-surface conditions and a quadratic pressure drop condition at the screen expressing an “integral” effect of the screen-induced cross-flow separation (or jet flow). New experimental data on the maximum wave elevations at the wall are compared with the theoretical predictions. Very good agreement is shown for the smallest forcing amplitudes (the forcing amplitude-to-tank width ratio is ≈0.001). Increasing the nondimensional forcing amplitude to ≈0.01 leads to discrepancies due to secondary resonance causing the energy context from the two primary-excited antisymmetric modes to other, first of all, symmetric modes. A further increase of the nondimensional forcing amplitude to 0.03 leads to more complex secondary resonance effects. Specific surface wave phenomena, e.g., wave breaking, are experimentally observed and documented by photographs and videos.
A dq axis theory of the magnetic, thermal, and mechanical properties of Curie motor
Authors: Trapanese Marco
Published: April 2011

A dq axis theory of a thermomagnetic Curie motor is presented. This theory allows one to estimate the performances of a Curie motor from its geometrical, magnetic, and thermal properties. The proposed approach shows that the thermomagnetic Curie motor is equivalent from a magnetic point of view to a dc electric machine. The physical meaning of the parameters used in the dq theory of Curie motor is explicated. The theory is validated by using experimental data.
Role of anisotropy configuration in exchange-biased systems
Authors: Jiménez E. , Camarero J. , Perna P. , Mikuszeit N. , Terán F. J. , Sort J. , Nogués J. , García-Martín J. M. , Hoffmann A. , Dieny B. , Miranda R.
Published: April 2011

We present a systematic study of the anisotropy configuration effects on the magnetic properties of exchange-biased ferromagnetic/antiferromagnetic (FM/AFM) Co/IrMn bilayers. The interfacial unidirectional anisotropy is set extrinsically via a field cooling procedure with the magnetic field misaligned by an angle βFC with respect to the intrinsic FM uniaxial anisotropy. High resolution angular dependence in-plane resolved Kerr magnetometry measurements have been performed for three different anisotropy arrangements, including collinear βFC=0∘ and two opposite noncollinear cases. The symmetry breaking of the induced noncollinear configurations results in a peculiar nonsymmetric magnetic behavior of the angular dependence of magnetization reversal, coercivity, and exchange bias. The experimental results are well reproduced without any fitting parameter by using a simple model including the induced anisotropy configuration. Our finding highlights the importance of the relative angle between anisotropies in order to properly account for the magnetic properties of exchange-biased FM/AFM systems.
Spin-spray deposited NiZn-Ferrite films exhibiting μr′ > 50 at GHz range
Authors: Obi Ogheneyunume , Liu Ming , Lou Jing , Stoute Stephen , Xing Xing , Sun Nian X. , Warzywoda Juliusz , Sacco Albert , Oates Daniel E. , Dionne Gerald F.
Published: April 2011

Ni0.27ZnxFe2.73-xO4 (with x = 0.03−0.1) thin films with high real permeability μr′ in the GHz range were fabricated by the spin spray process onto glass substrates in the presence of an external magnetic field of 360 Oe. These films exhibit high permeabilities that exceeded the Snoek limit for bulk NiZn-ferrite films and those previously reported for spin spray deposited ferrites. The NiZn-ferrite film with x = 0.06 is low in magnetic losses, having tanδm (μr″/μr′) ∼ 0.027 from 1 to 1.5 GHz, and a high ferromagnetic resonance (FMR) frequency of 2.7 GHz, while the x = 0.1 film exhibited a high μr′ of ∼50 and μr″ > 50 at 1 GHz. These properties are ideal for microwave applications such as antennas, inductors and electromagnetic interference (EMI) suppression in the GHz range.
Measurement and analysis of the diffuse reflectance of powdered samples at terahertz frequencies using a quantum cascade laser
Authors: Dean P. , Burnett A. D. , Tych K. , Khanna S. P. , Lachab M. , Cunningham J. E. , Linfield E. H. , Davies A. G.
Published: April 2011

We report terahertz (THz) diffuse reflectance measurements of bulk powdered samples at a frequency of 2.83 THz using a narrowband quantum cascade laser. Samples studied comprise polydisperse powders with absorption coefficients extending over two orders of magnitude from ∼3 cm−1 to >200 cm−1. Diffuse reflectance measurements are used to obtain the effective absorption coefficient of these samples from the backscattering cross-section, predicted under the quasi-crystalline approximation (QCA) in the T-matrix formulation and in conjunction with the Percus-Yevick pair distribution function. Results are compared with effective absorption coefficients obtained from THz time-domain spectroscopy measurements on pressed pellet samples, and show good agreement over the range of effective absorption coefficients studied. We observe that the backscattering cross-section predicted under the QCA is strongly dependent on both the real and imaginary components of the complex permittivity of the sample, and we show that reliable determination of the absorption coefficient from diffuse reflectance measurements therefore requires knowledge of the sample's refractive index. This work demonstrates the applicability of diffuse reflectance measurements, using a THz frequency quantum cascade laser, to the high-resolution spectroscopic analysis of bulk powdered samples at THz frequencies.
Extreme ultraviolet detection using AlGaN-on-Si inverted Schottky photodiodes
Authors: Malinowski Pawel E. , Duboz Jean-Yves , De Moor Piet , Minoglou Kyriaki , John Joachim , Horcajo Sara Martin , Semond Fabrice , Frayssinet Eric , Verhoeve Peter , Esposito Marco , Giordanengo Boris , BenMoussa Ali , Mertens Robert , Van Hoof Chris
Published: April 2011

We report on the fabrication of aluminum gallium nitride (AlGaN) Schottky diodes for extreme ultraviolet (EUV) detection. AlGaN layers were grown on silicon wafers by molecular beam epitaxy with the conventional and inverted Schottky structure, where the undoped, active layer was grown before or after the n-doped layer, respectively. Different current mechanisms were observed in the two structures. The inverted Schottky diode was designed for the optimized backside sensitivity in the hybrid imagers. A cut-off wavelength of 280 nm was observed with three orders of magnitude intrinsic rejection ratio of the visible radiation. Furthermore, the inverted structure was characterized using a EUV source based on helium discharge and an open electrode design was used to improve the sensitivity. The characteristic He I and He II emission lines were observed at the wavelengths of 58.4 nm and 30.4 nm, respectively, proving the feasibility of using the inverted layer stack for EUV detection.
Transition-metal 13-atom clusters assessed with solid and surface-biased functionals
Authors: Piotrowski Maurício J. , Piquini Paulo , Odashima Mariana M. , Da Silva Juarez L. F.
Published: April 2011

First-principles density-functional theory studies have reported open structures based on the formation of double simple-cubic (DSC) arrangements for Ru13, Rh13, Os13, and Ir13, which can be considered an unexpected result as those elements crystallize in compact bulk structures such as the face-centered cubic and hexagonal close-packed lattices. In this work, we investigated with the projected augmented wave method the dependence of the lowest-energy structure on the local and semilocal exchange-correlation (xc) energy functionals employed in density-functional theory. We found that the local-density approximation (LDA) and generalized-gradient formulations with different treatment of the electronic inhomogeneities (PBE, PBEsol, and AM05) confirm the DSC configuration as the lowest-energy structure for the studied TM13 clusters. A good agreement in the relative total energies are obtained even for structures with small energy differences, e.g., 0.10 eV. The employed xc functionals yield the same total magnetic moment for a given structure, i.e., the differences in the bond lengths do not affect the moments, which can be attributed to the atomic character of those clusters. Thus, at least for those systems, the differences among the LDA, PBE, PBEsol, and AM05 functionals are not large enough to yield qualitatively different results.
Mass equidistribution for automorphic forms of cohomological type on 𝐺𝐿₂
Authors: Marshall Simon
Published: April 2011

We extend Holowinsky and Soundararajan’s proof of quantum unique ergodicity for holomorphic Hecke modular forms on

S
L
(
2
,

Z

)

SL(2,\mathbb {Z})

, by establishing it for automorphic forms of cohomological type on

G

L
2

GL_2

over an arbitrary number field which satisfy the Ramanujan bounds. In particular, we have unconditional theorems over totally real and imaginary quadratic fields. In the totally real case we show that our result implies the equidistribution of the zero divisors of holomorphic Hecke modular forms, generalising a result of Rudnick over

Q

\mathbb {Q}

.
Association of a Novel Pinus monticola Chitinase Gene (PmCh4B) with Quantitative Resistance to Cronartium ribicola
Authors: Liu Jun-Jun , Sniezko Richard A. , Ekramoddoullah Abul K. M.
Published: April 2011

Multiple families of pathogenesis-related (PR) proteins are believed to contribute to plant quantitative resistance to various pathogens. Along with other host PR proteins, PR3 chitinase is one protein component participating in genetic resistance of western white pine (Pinus monticola) to the white pine blister rust (WPBR) pathogen (Cronartium ribicola). In the present study, we characterized a novel P. monticola class IV chitinase gene (PmCh4B) and further analyzed its nucleotide variations in the open-pollinated seed families of diverse geographical distribution and variable levels of quantitative resistance to C. ribicola infection. PmCh4B showed high haplotype diversity (Hd = 0.94) and nucleotide diversity (π = 0.00965), similar to those of other conifer genes related to environmental stresses. A low level of intragenic linkage disequilibrium (LD) (but most of the levels with statistical significance) was found within a distance of ≈800 bp. Based on PmCh4B haplotype frequency, moderate to high levels of population structure were observed among P. monticola seed families currently used in breeding programs for WPBR resistance (average FST = 0.163, P < 0.001). Association analysis revealed that allelic variants and multiple single-nucleotide polymorphisms of PmCh4B were significantly associated with quantitative levels of P. monticola resistance against C. ribicola. This work represents the first association study for quantitative resistance in western white pine pathosystem and provides a potential for marker-assisted selection in white pine breeding.
Eop1 from a Rubus Strain of Erwinia amylovora Functions as a Host-Range Limiting Factor
Authors: Asselin J. E. , Bonasera J. M. , Kim J. F. , Oh C.-S. , Beer S. V.
Published: April 2011

Strains of Erwinia amylovora, the bacterium causing the disease fire blight of rosaceous plants, are separated into two groups based on host range: Spiraeoideae and Rubus strains. Spiraeoideae strains have wide host ranges, infecting plants in many rosaceous genera, including apple and pear. In the field, Rubus strains infect the genus Rubus exclusively, which includes raspberry and blackberry. Based on comparisons of limited sequence data from a Rubus and a Spiraeoideae strain, the gene eop1 was identified as unusually divergent, and it was selected as a possible host specificity factor. To test this, eop1 genes from a Rubus strain and a Spiraeoideae strain were cloned and mutated. Expression of the Rubus-strain eop1 reduced the virulence of E. amylovora in immature pear fruit and in apple shoots. Sequencing the orfA-eop1 regions of several strains of E. amylovora confirmed that forms of eop1 are conserved among strains with similar host ranges. This work provides evidence that eop1 from a Rubus-specific strain can function as a determinant of host specificity in E. amylovora.
Nosocomial transmission of parainfluenza 3 virus in hematological patients characterized by molecular epidemiology
Authors: Lee A.V. , Bibby D.F. , Oakervee H. , Rohatiner A. , Ushiro‐Lumb I. , Clark D.A. , Mattes F.M.
Published: April 2011

A.V. Lee, D.F. Bibby, H. Oakervee, A. Rohatiner, I. Ushiro‐Lumb, D.A. Clark, F.M. Mattes. Nosocomial transmission of parainfluenza 3 virus in hematological patients characterized by molecular epidemiology. Transpl Infect Dis 2011: 13: 433–437. All rights reserved

Abstract: We report an outbreak of parainfluenza 3 virus involving 17 hematology–oncology patients on 2 hospital wards. Sequence analysis of clinical samples confirmed homology of strains for 16/17 patients and 1 healthcare worker. Epidemiological analysis of the outbreak supported the molecular data with nosocomial transmission of the same genetic strain as the cause of the outbreak.
Erythema nodosum in kidney transplant recipient: a rare complication of pneumonia treatment
Authors: Gregorini M. , Castello M. , Rampino T. , Esposito P. , Rosso R. , Borroni G. , Dal Canton A.
Published: April 2011

M. Gregorini, M. Castello, T. Rampino, P. Esposito, R. Rosso, G. Borroni, A. Dal Canton. Erythema nodosum in kidney transplant recipient: a rare complication of pneumonia treatment. Transpl Infect Dis 2011. All rights reserved

Abstract: Erythema nodosum (EN) is a cutaneous inflammatory reaction, usually reported in young women, but it is rarely observed among transplant patients. Localization in the lower extremities is typical, mostly involving the anterior surfaces of the legs. Several viral, bacterial, mycotic, and non‐infectious etiologies, such as autommune disorders, drugs, inflammatory bowel diseases, sarcoidosis, pregnancy, and malignancies, have been found. We describe the case of a young woman kidney transplant recipient developing bilateral, erythematous, warm nodules localized on the anterior surface of her legs after antibiotic treatment for pneumonia with levofloxacin. Her immunosuppression was sirolimus and mycophenolate mofetil. EN was diagnosed by skin biopsy; microscopic examination showed septal panniculitis with granulomas. As a complete remission of the lesions was obtained in our patient after interruption of levofloxacin therapy, we suspect that levofloxacin was involved in the pathogenesis of EN. In fact, the management of EN is based on the treatment of underlying or associated conditions.
Treatment of vitiligo with narrowband‐UVB (TL01) combined with tacrolimus ointment (0.1%) vs. placebo ointment, a randomized right/left double‐blind comparative study
Authors: Nordal E.J. , Guleng G.E. , Rönnevig J.R.
Published: April 2011

Background  Only a few, small double‐blind clinical trials have been reported for the treatment of vitiligo. Narrowband‐ultraviolet B (NB‐UVB) is an established form of treatment for this condition. Tacrolimus ointment is assumed to have an effect in some patients.

Objectives  To assess the additive effect of tacrolimus ointment (0.1%) once daily in vitiligo patients treated with NB‐UVB.

Methods  In a randomized double‐blind trial, patients with stable symmetrical vitiligo were treated half‐side with tacrolimus ointment (0.1%) and half‐side with placebo ointment. Whole body NB‐UVB was given twice or thrice weekly for at least 3 months. As a morphometric device, VisitrakTM was used to measure the area of the vitiligo target lesions.

Results  Of 40 patients, 27 had a better effect on the tacrolimus side. The degree of improvement was significantly better on the tacrolimus side (P = 0.005). The median reduction in the target lesion areas was 42.1% on the tacrolimus side and 29% on the placebo side. There was a correlation between the effect and the number of topical tacrolimus applications (P = 0.044), but there was no correlation with the number of UV treatments given; neither any significance of gender, age, skin type, duration of disease, familial occurrence of vitiligo nor presence of other autoimmune disease or atopy was observed. We found a significant reduction in the patients’ subjective disease impact during the treatment period (P < 0.001).

Conclusion  According to this study, the combination of NB‐UVB and tacrolimus ointment (0.1%) is more effective than UV treatment alone in patients with vitiligo. The effect is tacrolimus total dose‐dependent.
Structural determinants of allosteric antagonism at metabotropic glutamate receptor 2: mechanistic studies with new potent negative allosteric modulators
Authors: Lundström L , Bissantz C , Beck J , Wettstein JG , Woltering TJ , Wichmann J , Gatti S
Published: April 2011

BACKGROUND AND PURPOSE Altered glutamatergic neurotransmission is linked to several neurological and psychiatric disorders. Metabotropic glutamate receptor 2 (mGlu2) plays an important role on the presynaptic control of glutamate release and negative allosteric modulators (NAMs) acting on mGlu2/3 receptors are under assessment for their potential as antidepressants, neurogenics and cognitive enhancers. Two new potent mGlu2/3 NAMs, RO4988546 and RO5488608, are described in this study and the allosteric binding site in the transmembrane (TM) domain of mGlu2 is characterized.

EXPERIMENTAL APPROACH Site directed mutagenesis, functional measurements and β2‐adrenoceptor‐based modelling of mGlu2 were employed to identify important molecular determinants of two new potent mGlu2/3 NAMs.

KEY RESULTS RO4988546 and RO5488608 affected both [3H]‐LY354740 agonist binding at the orthosteric site and the binding of a tritiated positive allosteric modulator (3H‐PAM), indicating that NAMs and PAMs could have overlapping binding sites in the mGlu2 TM domain. We identified eight residues in the allosteric binding pocket that are crucial for non‐competitive antagonism of agonist‐dependent activation of mGlu2 and directly interact with the NAMs: Arg3.28, Arg3.29, Phe3.36, HisE2.52, Leu5.43, Trp6.48, Phe6.55 and Val7.43. The mGlu2 specific residue HisE2.52 is likely to be involved in selectivity and residues located in the outer part of the binding pocket are more important for [3H]‐LY354740 agonist binding inhibition, which is independent of the highly conserved Trp6.48 residue.

CONCLUSIONS AND IMPLICATIONS This is the first complete molecular investigation of the allosteric binding pocket of mGlu2 and Group II mGluRs and provides new information on what determines mGlu2 NAMs selective interactions and effects.
Growth Dynamics of the Canine Proximal Tibial Physis
Authors: McBrien Jr. Charles S. , Vezzoni Aldo , Conzemius Michael G.
Published: April 2011

Objective:To determine growth of the proximal tibial physis in the Labrador Retriever, a breed of dog at risk for rupture of the cranial cruciate ligament (CCL).

Animals:Male Labrador Retriever dogs (n=6).

Methods:Tantalum markers (0.5 mm diameter) were implanted in the right proximal tibial epiphysis and metaphysis of each dog at 16 weeks of age. Lateral and craniocaudal radiographic projections of the tibia were made monthly and longitudinal growth was assessed from radiographs; a growth curve was generated from the data. Data from dogs that had undergone proximal tibial epiphysiodesis (PTE) was compared with the growth curve to demonstrate if the growth curve accurately predicted changes in the growth associated with this procedure.

Results:Growth rate of individual dogs decreased slowly and non‐linearly over the 1st year of age. Growth from the proximal tibial physis is described.

Conclusions:Growth of individual dogs described here follows the model of saltation and stasis. The growth curve generated predicted the change in tibial plateau angle (TPA) for two Labrador Retrievers that had PTE (±1°).
DIE ROLLE DER SPEICHELSEKRETE IM WECHSELVERHÄLTNIS ZWISCHEN TIER UND NAHRUNGSPFLANZE BEI HOMOPTEREN UND HETEROPTEREN
Authors: NUORTEVA PEKKA
Published: April 2011

Im Speichel der Rhynchoten gibt es verschiedene Verdauungsenzyme, die eine weitgehende Anpassung hinsichtlich der Art der Nahrung aufweisen und bei der Verdauung wichtig sind. Zugleich gibt es im Rhynchotenspeichel auch Pflanzenwuchs hemmende Stoffe, Auxine und Viren, die alle Krankheitszustände bei den Nahrungspflanzen verursachen welche ihrerseits die Lebensbedingungen der Schädlinge fördern.

The above article is a short survey of the relation between the salivary secretions of the Hemiptera and their host plants.

In analyses of the composition secretions in the salivary glands of phytophagous Homoptera and Heteroptera, the most extensive work has been done on the digestive enzymes. Proteases, amylases, saccharase, maltase, pectinase and lipase have been detected, but most commonly only 2–3 of these occurs in any one species. An adaptation of the enzyme complement to the diet is evident and in this respect the feeding site used by the insect is especially decisive to the enzyme composition of the saliva. Proteases and amylases occur in the saliva of mesophyll feeders, but are absent in phloem feeders, for which they are useless because, from the insect's point of view, the food is already digested. The adaptation of the salivary enzymes to the nature of the food seems to be largely inherited, for a diet containing nothing but sucrose does not induce adaptive changes in the enzyme content of the salivary glands. By contrast, papain seems to be transferred from a synthetic food to the salivary glands.

The disease symptoms caused in plants by the salivary toxins of Homoptera and Heteroptera have many similarities to those caused by abnormal amounts of growth hormones. Indole‐tri‐acetic acid has been detected in extracts of crushed aphids and leafhoppers, although no growth stimulating hormones have been detected in salivary glands dissected from several heteropterous bugs and one aphid. On the contrary, substances inhibiting plant growth exist in the salivary glands of many Heteroptera and in at least one aphid. In some experiments with a heteropterous bug, indole‐tri‐acetic was observed to have been transferred from a synthetic diet to the salivary glands. It seems possible that auxins, enzymes and other phytotoxic substances occurring in the salivary glands of insects may at last in some cases originate from the host plant and are not produced by the insect.

The salivary enzymes without doubt play an important role in the digestion of the insects secreting them. They are important also in the differentation of Homoptera and Heteroptera to different modes of life. The auxins or auxin inhibitors, as wel as all phytotoxic substances in the salivary glands of Homoptera and Heteroptera are significant for these animals by changing the physiological state of the host plant in such a direction that its suitability as a source of food increases.
PHYSIOLOGICAL CONDITION OF THE HOST‐PLANT AND SUSCEPTIBILITY TO APHID ATTACK
Authors: KENNEDY J. S.
Published: April 2011

Familiar types of physiological variation in aphid host‐plants, such as in the pattern of growth or the water economy, have a great influence upon the growth, development and behaviour of aphids, for reasons that we are beginning to understand. They would merit fuller exploitation for the purposes of aphid control.

1. Es ist bekannt, daß unregelmäßig auftretende Sekundärstoffe unbekannter Funktion in den Pflanzen oft die Reize darstellen, mit deren Hilfe die Insekten ihre Wirtspflanzen unterscheiden. Es wird behauptet: I. daß vorwiegend solche Reize für die Wirtswahl verantwortlich seien, II. daß alle für die Insekten notwendigen Grundnährstoffe von fast allen Blättern in ausreichendem Maße geliefert würden und daß deshalb III. die für den Stoffwechsel der Pflanzen wie der Insekten als wichtig bekannten häufigen. Verbindungen eine geringe Rolle als Ursache der Präferenzerscheinungen spielten (sowohl als unmittelbare Reize wie als physiologisch mit ihnen verbundene Signalfaktoren). Die Theorie der “doppelten Unterscheidung” bei der Wirtswahl der Blattläuse, andererseits, fordert, daß solche “Ernährungs” reize eine bedeutende Rolle spielten, zusammen mit spezifisch pflanzlichen Reizen; und daß der Nährstoffgehalt der Pflanzensäfte, von dem sich die Aphiden ernähren, dem physiologischen Zustand der Pflanzen entsprechend, in weiten Grenzen schwankt.

2. Es wird hier darauf hingewiesen, daß das Studium des für die Ernährung wichtigen pflanzenphysiologischen Aspekts der Beziehungen zwischen Aphiden und ihren Wirtspflanzen heutzutage wissenschaftlich und praktisch weit fruchtbarer sein dürfte als das Studium des auf die speziell pflanzlichen Sekundärstoffe bezogenen Aspekts, da bereits viel über die physiologische Variabilität bei den Pflanzen bekannt ist und da dies den Sammelpunkt aller landwirtschaftlichen Wissenschaft darstellt.

3. Zur Unterstützung dieser Auffassung wird über drei (weitgehend unveröffentlichte) Arbeiten über Aphiden (Tuberolachnus salignus Gmelin and Aphis fabae Scopoli) zusammenfassend berichtet. Sie zeigen, daß gewöhnliche Formen der physiologischen Verschiedenheit unter den Pflanzen, wie etwa Eigentümlichkeiten in Wachstum und Entwicklung oder im Wasserhaushalt, sowohl die Ernährung wie das Verhalten der Blattläusse beeinflussen. Mit der Zunahme weiterer Kenntnis solcher Unterschiede könnten wahrscheinlich im Hinblick auf die Aphidenresistenz von Pflanzen viel größere Fortschritte erzielt werden, als bisher durch Anbau‐ und Pflanzenzuchtmethoden für möglich gehalten wurde.
THE QUANTITATIVE STUDY OF SOIL MEIOFAUNA
Authors: MURPHY PAUL W.
Published: April 2011

Der ‘geteilte‐Trichter’ Ausleseapparat, eine Abänderung der Tullgren‐Trichtermethode zur Auslese der Bodenfauna, sowie ein Versuch zur Überprüfung der Apparatur und der Einfluss der Behandlung der Proben auf die Wirksamkeit der Auslese werden beschrieben. Bei Heidesandproben werden die besten Resultate erhalten, wenn Streu und Auflagehumus getrennt ausgelesen werden, der letztere in ungestörten, dünnen Schichten (1,3–1,9 cm). Der Unterschied zwischen Zimmertemperatur und der erwärmter Trichter (Lufttemperatur 30–35° C) hinsichtlich der Auslese der Streu ist unbedeutend; beim Auflagehumus ist die Erwärmung des Trichters jedoch wirkungsvoller.
THE IMPORTANCE OF DRINKING WATER TO LARVAL INSECTS
Authors: MELLANBY KENNETH , FRENCH R. A.
Published: April 2011

Many insect larvae have been found to drink water. These include larvae inhabiting stored products, phytophagous species, larvae found in the soil, and species dehydrated during diapause. The water taken in may enable the larvae to withstand unfavourable conditions.

Wassertrinken ist bei vielen Insektenlarven festgestellt worden. Die Fälle des Trinkens lassen sich folgendermaßen einteilen:

a. Larven, die von Speicherprodukten leben. Der Mehlwurm, Tenebrio molitor, kann unter trockenen Verhältnissen leben, trinkt aber bereitwillig. Nach Tränkung kann diese Art bei höheren Temperaturen leben und heranwachsen als Larven, denen kein Wasser zur Verfügung steht. Wahrscheinlich verhalten sich manche andere Speicherschädlinge ähnlich.

b. Phytophage Larven. Viele decken ihren gesamten Wasserbedarf aus der Nahrung, aber hungernde Individuen oder solche, die von verwelkten Blättern leben, können bereitwillig trinken und so ihren Wasserhaushalt wiederherstellen.

c. Bodeninsekten. Obwohl manche Larven, so z.B. die Drahtwürmer Agriotes, Wasser durch ihre Haut absorbieren, kommt auch Trinken vor. Sogar Agriotes trinkt unter gewissen Umständen. Andere Larven haben undurchlässige Cuticulae und trinken bereitwillig Wasser, wenn es erforderlich ist, ihr Wassergleichgewicht wiederherzustellen.

d. Diapausierende Larven. Viele Larven haben während der Diapause einen niedrigen Wassergehalt, und bevor dieser nicht ansteigt, kommt die Diapause normalerweise nicht zum Abschluß. Bei Larven, die während der Diapause bewegungsfähig sind, kann das Wassertrinken eine Vorbedingung für die Beendigung der Diapause sein.
THE MODE OF ACTION OF AN ORGANOPHOSPHORUS INSECTICIDE (DDVP)
Authors: VAN ASPEREN K.
Published: April 2011

1. Es konnte gezeigt werden, dass die Giftigkeit und besonders die Dampfgiftigkeit von DDVP (0,0‐Dimethyl 0–2,2 Dichlorvinyl‐Phosphat) gegenüber Stubenfliegen (Musca domesttca) sehr viel grosser ist als gegenüber Mäusen. Dieser Unterschied in der Giftwirkung ist auffällig mit einem Unterschied in der Hemmbarkeit der Cholinesterasen in homogenisierten Geweben korreliert (siehe Tabelle I).

2. Der Unterschied in der Hemmbarkeit wurde eingehend in der Absicht untersucht, nach‐zuforschen, ob es sich hier um eine Differenz zwischen den Enzymen selbst oder um einen Unterschied bei anderen in den Homogenaten anwesenden Substanzen oder Faktoren handelt. Man könnte dabei an die Anwesenheit bestimmter Eiweissmoleküle denken, die DDVP binden und dadurch inaktivieren. Das Ergebnis unserer Untersuchungen zeigt, dass die Enzyme selber auffallende Unterschiede aufweisen, die höchstwahrscheinlich zu einem sehr beträchtlichen Teil für den Unterschied in der Hemmbarkeit verantwortlich gemacht werden können.

3. Obwohl die Hemmungsreaktionen sehr verschieden sind, unterscheidet sich die Fliegen‐Cholinesterase in ihrer Substratspezifizität nicht wesentlich von der sogenannten “true Cholinesterase”, die im Gehirn der Saügetiere gefunden wird.

4. Die Bedeutung unserer Ergebnisse wird speziell in Beziehung auf die Frage diskutiert, welche Rolle die Cholinesterase‐Hemmung bei der Vergiftung durch DDVP spielt. Da gefunden wurde, dass auch die Ali‐Esterase‐Aktivität (Substrate: Methylbutyrat und Tributyrin) der Fliegen in vitro viel stärker von DDVP gehemmt wird als diejenige des Mäusegehirns, wird in dieser Diskussion auch die Möglichkeit einer Ali‐Esterase‐Hemmung als Ursache der Vergiftung hervorgehoben.
INFLUENCE OF SUBLETHAL DOSES OF DDT UPON THE MULTIPLICATION RATE OF SITOPHILUS GRANARIUS (COLEOPT. CURCULIONIDAE)
Authors: KUENEN D. J.
Published: April 2011

Sitophilus granarius was exposed to very low doses of DDT mixed with the wheat in which it was reared (0.0, 0.10, 0.125, 0.25 mg DDT per 100 g wheat). The weevils exposed to 0.10 and 0.125 mg produced about 20% more offspring than the unexposed weevils. At 0.25 mg DDT the reproduction was even higher per living female in the first five weeks, but mortality was high and the total number of offspring was much lower than in the other cultures.

The results are compared with previous results, obtained by exposing Metatetranychus ulmi (Acari, Tetranychidae) to DDT and it is suggested that the less susceptible an arthropod species is to DDT the greater the possibility that stimulation of reproduction will be found.

Sitophilus granarius wurde sehr geringen Dosen von DDT ausgesetzt, die Weizen beigemischt waren, in dem er gezüchtet wurde (0,0, 0,10, 0,125, 0,25 mg DDT auf g Weizen). Käfer, die 0,10 und 0,125 mg erhielten, produzierten über 20% Nachkommen mehr als die Kontrollkäfer. Sogar bei 0,25 mg DDT war die Vermehrung pro lebendem Weibchen in den ersten fünf Wochen höher, aber die Mortalität groß und die Gesamtzahl der Nachkommen viel geringer als in den anderen Zuchten.

Die Resultate werden mit früheren Ergebnissen verglichen, die bei der Behandlung von hietatetranychus ulmi (Acari, Tetranychidae) mit DDT erhalten worden waren und es wird angenommen, daß die Möglichkeit, stimulierende Wirkungen zu finden, umso größer ist, je weniger empfindlich eine Arthropoden‐Art gegenüber DDT ist.
THE ALARM REACTION OF MOSQUITO LARVAE
Authors: MELLANBY KENNETH
Published: April 2011

When Aedes larvae are alarmed they swim actively to the bottom; they recover by floating passively upwards. Culex and Anopheles larvae sink passively when alarmed; they swim actively to the surface on recovery. Repeated stimulation produces “stimulus satiation”, but a different type of stimulus can then give a complete response. Geotaxis and phototaxis are concerned in the alarm reaction in Aedes; phototaxis can overrule geotaxis. The chill coma temperature of these larvae is several degrees cooler than that at which the alarm reaction takes place. Acclimatization can alter the position of both.

Bei drei Arten von Stechmücken‐Larven wurde die Schreck‐Reaktion untersucht. Alle Larven verschwinden bei Reiz von der Wasseroberfläche, aber der Reaktions‐Mechanismus unterscheidet sich bei den verschiedenen Arten. Aedes aegypti ist leichter als Wasser. Die Larven schwimmen aktiv zum Boden und kehren durch Aufwartstreiben passiv wieder zur Wasseroberfläche zurück. Die Larven von Culex und Anopheles sind schwerer als Wasser. Sie sinken bei Reiz passiv zum Boden, die Rückkehr zur Wasseroberfläche ist ein aktiver Prozess, welcher Schwimmbewegungen der Larven notwendig macht.

Wiederholter Reiz führt zur “Reizsättigung”. Hat eine Larve aufgehört, auf einen Anreiz (z.B. Schwingung) zu reagieren, reagiert sie aber sofort auf einen anderen Reiz (z.B. Licht). Dieses deutet an, dass sich die Sinnes‐Rezeptoren angepasst haben, dass aber die den Effekt bewirkenden Muskeln nicht ermüdet sind.

Aedes‐Lamen sind nach Reiz negativ phototaktisch. Sie sind ausserdem positiv geotaktisch, aber die negative Phototaxis ist die stärkere Reaktion. Culex‐ und Anopheles‐Larven erschlaffen, wenn sie “gereizt” werden, sie sinken in diesem Zustand passiv, sie reagieren nicht auf Wechsel in der Licht‐Intensität.

Die zu Aktivitätslosigkeit führende Temperatur ist um einige Grade kälter als die tiefste Temperatur, bei welcher Schreck‐Reaktion noch stattfindet. Anpassung, welche vor 24 Stunden erfolgt, kann sowohl die zu Aktivitätslosigkeit führende Temperatur, als auch die Temperatur ändern, bei welcher noch eine Schreck‐Reaktion ausgelöst wird.
INFLUENCE DE CERTAINS FACTEURS ECOLOGIQUES SUR LA PONTE ET LE DÉVELOPPEMENT DES CÉTOINES GRISES
Authors: HURPIN B.
Published: April 2011

Des élevages de laboratoire ont été entrepris pour préciser l'action des principaux facteurs écologiques sur le développement des larves de Cétoines grises. Les recherches ont porté surtout sur Epicometis squalida Scop. et Oxythyrea funesta Poda.

L'influence de la température et de la nature du milieu fut plus particulièrement étudiée. Ces élevages mettent en évidence les différences de comportement selon l'espèce considérée, en ce qui concerne le rǒle de la température, la sensibilté aux maladies ou les besoins alimentaires. O. funesta est l'espèce la moins exigeante comme conditions de milieu et la plus résistante aux mycoses.

Ces faits expliquent vraisemblablement les différences de répartition géographique de ces coleoptéres: O. funesta étant plus largement répandu que les Epicometis.

Die Laborzuchten wurden hauptsächlich unternommen, um die Wirkung der wichtigsten ökologischen Faktoren auf die Entwicklung der Larven der grauen Rosenkäfer (“Cétoine grise”) zu klären. Die Untersuchungen erstreckten sich in der Hauptsache auf die Arten Epicometis squalida Scop. und Oxythyrea funesta Poda.

Besonders wurde dabei der Einfluss von Temperatur und andere Umweltbedingungen untersucht. Im Verlaufe dieser Zuchten zeigten sich Unterschiede in der Widerstandsfähigkeit der verschiedenen Arten gegen Temperatureinflüsse, in der Empfindlichkeit für Krankheiten, sowie ihrer Nahrungsbedürfnisse.

O. funesta ist die gegen Umwelteinflüsse am wenigsten empfindliche Art, aber auch die widerstandsfähigste gegen Mykosen. Diese Tatsachen erklären sehr wahrscheinlich die Unterschiede in der geographischen Verbreitung dieser Coleopteren: O. funesta findet sich weitaus verbre***rteter als Epicometis.
EXPERIMENTS WITH SUCTION TRAPS TO ASSESS THE ABUNDANCE OF SYRPHIDAE (DIPTERA), WITH SPECIAL REFERENCE TO APHIDOPHAGOUS SPECIES
Authors: BANKS C. J.
Published: April 2011

Preliminary information on the abundance of some common species of Syrphidae was obtained from the catches in five suction traps, operated at Rothamsted during the summers of 1951, 1952 and 1953. Six of the eight “abundant” species were aphidophagous.

The numbers of the individual species recorded varied from year to year, with the time of year, and from place to place.

Although the catches could not be correlated with the immediate weather conditions, the large differences between them could be associated with the differences in the general weather conditions of the three years. Syrphidae were few in the spring, although most species showed a small peak of numbers then, and maximum catches of nearly all species were recorded in late summer (August).

At two different localities, there were conspicuous differences in the abundance of individual species and in the composition of the catches. Where the vegetation was varied, Syrphidae were more diverse and more abundant than where the vegetation was uniform. Some species occurred in one locality but not in the other. The size and composition of the catch were not obviously affected by the kind of vegetation immediately around a trap.

Some of the many factors affecting the abundance of Syrphidae are discussed.

VERSUCHE ZUR ERMITTLUNG DER HÄUFIGKEIT VON SCHWEBFLIEGEN (DIPTERA, SYRPHIDAE) MIT SAUGFALLEN, UNTER BESONDERER BERÜCKSICHTIGUNG APHIDIVORER ARTEN

Ein vorläufiges Bild über die Häufigkeit einiger gewöhnlicher Syrphidenarten ließ sich aus Fängen von 5 Saugfallen gewinnen, die während der Sommer 1951, 1952 und 1953 in Rothamsted arbeiteten. Unter den 8 häufigen Arten befanden sich 6 aphidivore.

Die Individuenzahl der einzelnen untersuchten Arten schwankte von Jahr zu Jahr, im Jahresablauf sowie von Ort zu Ort.

Obwohl die Fänge nicht zu den unmittelbaren Wetterbedingungen in Beziehung gesetzt werden können, so könnten die großen Unterschiede zwischen ihnen doch mit den Unterschieden im allgemeinen Witterungsverlauf der 3 Jahre verbunden sein. Im Frühling gab es nur wenige Schwebfliegen, obwohl die meisten Arten dann einen kleinen Häufigkeitsgipfel aufwiesen; die größten Fangzahlen wurden bei fast allen Arten im Spätsommer (August) festgestellt.

An zwei verschiedenen Orten bestanden auffällige Unterschiede in der Häufigkeit der einzelnen Arten und in der Zusammensetzung der Fänge. Wo die Pflanzenbestände wechselten, waren die Syrphiden verschiedenartiger und häufiger als dort, wo die Vegetation gleichförmig war. Einige Arten erschienen an einem Ort, aber nicht an dem anderen. Die Größe und Zusammensetzung des Fanges wurden von der Art der Vegetation in der unmittelbaren Umgebung der Falle nicht merklich beeinflußt.

Einige der vielen Faktoren, welche die Häufigkeit der Syrphiden beeinflussen, werden besprochen.
DIFFERENTIAL HOST RELATIONS OF THE SEXES IN PARASITIC HYMENOPTERA1
Authors: FLANDERS STANLEY E.
Published: April 2011

The divergent ontogeny of the male, a unique phenomenon characterizing certain genera of the Aphelinidae, has its physiological bases in the environmental control of sex permitted by the haploid origin of the male and the diploid origin of the female and in the efficiency of the chalcidoid type of spermatheca which, during the process of oviposition, brings the environmentally activated sperm into contact with the egg. This divergence is correlated with the sexual dimorphism and the sexual ditrophism of the early developmental stages. It is psychologically manifested in a number of species by a marked difference in the host relations of the aphelinid female before and after mating. The climax of differential host relations within a species is the production of the female in a coccid host and the production of the male in a lepidopterous host. The aberrant development of the male tends to increase the capacity of the species to survive at low host densities.

UNTERSCHIEDLICHE WIRTSVERHÄLTNISSE DER GESCHLECHTER BEI PARASITISCHEN HYMENOPTEREN

Nachdem 1935 die obligatorisch wirtsverschiedene Geschlechterentwicklung bei den parasitischen Hymenopteren entdeckt wurde, ist dieses Phänomen bei ca 80% der bekannten Apheliniden, die in Schildläusen und Mottenschildläusen schmarotzen, gefunden worden. Die Kenntnis dieses Phänomens ermöglichte die Züchtung und Ansiedlung von 2 Arten solcher Parasiten in Californien. Die wirtsverschiedene Geschlechterentwicklung besteht in der aberranten Entwicklungsgeschichte des Männchens sowie der geschlechtsgebundenen Ditrophie mit Dimorphismus der Larvenstadien. Bei einigen Arten ist sie gekoppelt mit psychologischen Unterschieden zwischen begatteten und unbegatteten Weibchen, die dann verschiedene Wirtspräferenzen zeigen. Diese bemerkenswerte Spaltung der Wirtspräferenzen steht wohl teilweise in Zusammenhang mit der Funktion der Spermatheca des Chalcidoiden‐Typs, die äußerst empfindlich auf wirtseigene Stimuli anzusprechen pflegt. Es handelt sich um ein Wirts‐Beziehungs‐Phänomen, welches die Wirtsfindungsrate der Art zu erhöhen pflegt. Die ontogenetischen Abweichungen in der Entwicklung der Männchen dürften zur Phylogenie der Apheliniden in keiner Beziehung stehen.
THE ECOLOGY OF THE FEMALEHAEMATOPOTA INSIDIATRIXAUSTEN (DIPTERA, TABANIDAE) IN SOUTHERN RHODESIA
Authors: BARRASS ROBERT
Published: April 2011

The habitat ofH. insidiatrix, in the region of Main Camp, Wankie National Park, is considered briefly. The seasonal occurrence of the fly is studied and its activity throughout the day. Comparisons are drawn with previous work in colder climates.

DIE ÖKOLOGIE DER WEIBUCHENHAEMATOPOTA INSIDIATRIXAUSTEN (DIPTERA, TABANIDAE) IN SÜD‐RHODESIEN

Die Heimat vonH. insidiatrix, in der Nähe von Main Camp, Wankie National Park, wird kurz betrachtet. Das jahreszeitliche Vorkommen der Fliege und ihre Aktivität im Tagesverlauf werden untersucht. Die Resultate werden mit denen von früheren Untersuchungen in kälteren Klimaten verglichen.