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Abstract: The present study aimed to analyze sex differences in arithmetical performance in a large-scale sample of 390 children (193 boys) frequenting grades 1–9. Past research in this field has focused primarily on average performance, implicitly assuming homogeneity of variance, for which support is scarce. This article examined sex differences in arithmetical operations (addition, subtraction, multiplication and division) in central tendency and variability. Central tendency analyses revealed a male advantage, predominantly in addition and subtraction, from grade 6 onward. Variability analyses showed that sex differences were largest among higher achievers and absent among lower achievers. Thus, central tendency and variability analyses provide complementary information on sex differences in arithmetical performance. In conclusion, sex differences in arithmetical performance exist, but depend on the studied arithmetical operation, age group and achievement level. The present study thereby offers new directions for future research by indicating the need for a broader perspective on sex differences. [Copyright &y& Elsevier]

We develop a numerical model to explore the polarization-dependent compression of multi-mJ laser pulses in a gas-filled hollow fiber. We show how losses and instabilities due to cycling of pulse energy between fiber modes can be efficiently minimized using circularly polarized light and adjusting simple experimental parameters such as pulse energy, chirp and gas pressure. This should help scale the peak power of few-cycle pulses available for high-field experiments using standard hollow fiber compressors. We also discuss the limits of this approach. [ABSTRACT FROM AUTHOR]

80 μJ, 6 fs, CEP-stable high-contrast injector is demonstrated. The device relies on standard pulse post-compression in hollow-core fiber followed by a temporal filter based on cross-polarized wave generation. Pulses with a Gaussian spectrum over 350 nm, centered at 750 nm, are generated. Temporal measurements show that the contrast of the few-cycle pulses is enhanced on a femtosecond and picosecond time scale. The carrier-envelope phase stability is preserved (0.3 rad RMS). These performances make the system an ideal seed laser for high-power, high-contrast OPCPA systems. [ABSTRACT FROM AUTHOR]

We show that a standard hollow-core fiber (HCF) compressor device can be used to efficiently compress multi-mJ energy laser pulses down to few-cycle duration, when seeded with linearly chirped, circularly polarized pulses. With this approach, we routinely generate carrier-envelope phase (CEP)-locked, 1.6 mJ, 4.8 fs pulses using only 3 mJ, 25 fs pulses as the seed. [ABSTRACT FROM AUTHOR]

We report the routine generation of sub-5-fs laser pulses with 1-mJ energy and stable carrier–envelope phase at 1-kHz repetition rate, obtained by compressing the multi-mJ output from a phase-locked Ti:sapphire amplifier in a rare-gas-filled hollow fiber. The dual-stage amplifier features a hybrid transmission grating/chirped mirror compressor providing 2.2-mJ, 26-fs pulses at 1 kHz with standard phase deviation of 190 mrad rms. We demonstrate hour-long phase stability without feedback control of grating position or rigorous control of the laser environment, simply by using small pulse stretching factors in the amplifier, which minimize the beam pathway in the compressor. The amplifier also integrates a versatile AOPDF (acousto-optic programmable dispersive filter) for closed-loop spectral phase optimization. The various factors influencing the overall phase stability of the system are discussed in detail. Using the optimized output, 1-mJ, 4.5-fs pulses are generated by seeding the neon gas filled hollow fiber with a circularly polarized input beam. A standard phase deviation of 230 mrad after the HCF is obtained by direct f-to-2 f detection and slow-loop feedback to the oscillator locking electronics without any additional spectral broadening. [ABSTRACT FROM AUTHOR]

The characterization of a temporal filter based on cross-polarized wave generation working in the few-optical-cycle regime is presented. We show that this device dramatically improves the spectral quality of the ultrashort seed pulses, opening the way to the production of sub-10 fs pulses with high incoherent and coherent contrast. The dispersion compensation conditions for an optimized behavior of the process are experimentally and theoretically discussed. [ABSTRACT FROM AUTHOR]

In this paper we present the first comprehensive study of the role of spectral phase on cross-polarized wave (XPW) generation using sub-30 femtosecond (fs) laser pulses. XPW generation improves the temporal contrast and shortens the pulse duration of fs chirped pulse amplification (CPA) lasers. For Ti:Sa lasers, compression below 30 fs is non-trivial and therefore never perfect. We therefore systematically analyze the effect of an arbitrary input spectral phase on the output spectrum and efficiency of the XPW process, both theoretically and experimentally. We derive the maximum acceptable value of residual phase for a given initial pulse duration in order to efficiently drive the XPW process for pulse shortening and contrast improvement. [ABSTRACT FROM AUTHOR]

Rhodococcus equi, a facultative intracellular bacterium, causes severe pneumonia in foals. Evidence suggests that most foals become infected very early in life, when they have immature or ineffective innate immune responses. This study evaluated the antimicrobial activity of gallium against R. equi, as a potential chemoprophylactic and therapeutic agent. Rhodococcus equi was grown in media with various concentrations of gallium nitrate (GN), with and without excess iron. GN significantly inhibited growth and killed R. equi, and these effects were abolished with excess iron. Antimicrobial effects of Ga appear to be related to its interference with iron metabolism. Mice were treated orally with gallium maltolate (GaM), 10 or 50 mg/kg BW, or distilled H2O prior to and after experimental infection with R. equi. Six days post-infection, organs were harvested and R. equi concentrations assessed, and serum gallium concentrations determined. GaM was absorbed in a dose-dependent manner, and R. equi tissue burdens were greater in control mice than in all GaM-treated mice. GaM may aid in the control of disease by preventing development of overwhelming R. equi tissue burdens prior to the establishment of requisite innate and adaptive immune responses. [ABSTRACT FROM AUTHOR]

We investigate the temporal confinement of high order harmonic pulses generated by a femtosecond (fs) infrared (IR) pulse with a time varying polarization. We use a set of two birefringent quartz plates to modulate the IR polarization. It produces a short temporal gate of linear polarization where harmonics are efficiently generated during a small fraction of the IR pulse. By rotating one of the plates, the gate width can be continuously varied between 70 fs down to 7 fs. The XUV pulse duration is measured by cross-correlation with a probe IR pulse of 12 fs. When the gate width is decreased, a clear temporal confinement of the XUV emission is observed through the cross correlation signal. This experiment is the first direct experimental evidence in the temporal domain that the polarization gating technique can be used to significantly shorten the harmonic pulse duration. [ABSTRACT FROM AUTHOR]

We present energy-resolved cross-correlation measurements of extreme ultraviolet (XUV) pulses generated as high harmonics of femtosecond pulses from a 1 kHz titanium-sapphire laser. The harmonic pulses are probed by a fraction of the fundamental laser pulse at 800 nm, in a noncollinear geometry, allowing us to vary independently the parameters of the harmonic pump and near-infrared probe pulses. We measure the so-called “sidebands” in the photoelectron spectrum of argon corresponding to the absorption of a harmonic photon plus or minus one probe photon. Spectrally resolving the cross-correlation signal allows us to characterize the time-dependent frequency of the XUV pulse. [ABSTRACT FROM AUTHOR]

The contact behavior of a commercial elastomer interconnect, composed of silicone rubber and silver particles, was evaluated under thermal and mechanical stresses. Its contact resistance demonstrated a linear relationship in a log-log plot with contact force at room temperature; however, a deviation of the trend occurred when temperature was changed. With the interconnect compressed under a constant force, a fluctuation in contact resistance was initiated by a change of temperature. This phenomenon may be attributed to the inherent conduction mechanisms of the elastomer interconnect. The multiple interfaces between metal particles make the contact sensitive to a variety of factors. This sensitivity may have a direct impact on its long-term reliability. [ABSTRACT FROM PUBLISHER]

White-rot fungi applied for soil bioremediation have to compete with indigenous soil microorganisms. The effect of competition on both indigenous soil microflora and white-rot fungi was evaluated with regard to degradation of polycyclic aromatic hydrocarbons (PAH) with different persistence in soil. Sterile and non-sterile soil was artificially contaminated with 14C-labeled PAH consisting of three (anthracene), four (pyrene, benz[a]anthracene) and five fused aromatic rings (benzo[a]pyrene, dibenz[a,h]anthracene). The two fungi tested, Dichomitus squalens and Pleurotus ostreatus, produced similar amounts of ligninolytic enzymes in soil, but PAH mineralization by P. ostreatus was significantly higher. Compared to the indigenous soil microflora, P. ostreatus mineralized 5-ring PAH to a larger extent, while the indigenous microflora was superior in mineralizing 3-ring and 4-ring PAH. In coculture the special capabilities of both soil microflora and P. ostreatus were partly restricted due to antagonistic interactions, but essentially preserved. Thus, soil inoculation with P. ostreatus significantly increased the mineralization of high-molecular-weight PAH, and at the same time reduced the mineralization of anthracene and pyrene. Regarding the mineralization of low-molecular-weight PAH, the stimulation of indigenous soil microorganisms by straw amendment was more efficient than application of white-rot fungi. [ABSTRACT FROM AUTHOR]

Many of the reliability issues affecting separable connectors can be traced to the contact interface. In order to design robust, reliable connectors and sockets, the effects and interactions of design parameters on the reliability of the contact interface must be examined, especially in the limited design space presented by such applications as high density LGA sockets. A full test matrix was applied with varying levels of normal force, gold-plating thickness, contact geometry, mixed flowing gas exposure, and wipe. A statistical analysis of the results and multiple linear regression models are also presented. When making contact to gold-plated surfaces, the presence of corroded pore sites dramatically affected the contact resistance. Contact resistance readings were taken both on and off corroded pore sites. When contact was made off corroded pore sites, the resistance values were not significantly higher than unexposed gold values and the combination of normal force and contact geometry were the most significant variables. Small amounts of wipe were shown to decrease the contact resistance and backwipe was shown to have little effect on the contact resistance. Contact on corroded pore sites was found to yield extremely high contact resistance readings, many of which were open-circuit. In general, satisfactory results were achieved if contact was not attempted on corroded pore sites. [ABSTRACT FROM AUTHOR]

The potential for aerobic mineralization of [U-14C]dibenzo- p-dioxin (DD) was investigated in samples of three different agricultural soils already contaminated with polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDD/F) by industrial activities. The influence of amendments, i.e. wheat straw and compost, and of soil treatment by inoculation with lignolytic fungi, grown on wheat straw substrate, was tested. All the soils tested contained an indigenous DD-mineralizing microflora. The soil characterized by the highest organic matter content and the highest content of soil microbial biomass displayed the best DD mineralization of 36.6% within 70 days, compared with the two organic-matter-poor soils with an endogenous DD mineralization of 19.5% and 23.3% respectively. Amendments with compost increased DD mineralization up to 28% in both soils with low organic matter and microbial biomass content, but did not affect mineralization in the organic-matter-rich soil. Addition of wheat straw had no constant influence on DD mineralization in the soils tested. The best DD mineralization resulted from inoculation with lignolytic white-rot fungi ( Phanerochaete chrysosporium, Pleurotus sp. Florida, Dichomitus squalens) and with an unidentified lignolytic fungus, which was isolated originally from a long-term PCDD/F-contaminated soil. A mineralization of up to 50% within 70 days was reached by this treatment. The influence of inoculated fungi on mineralization differed between the soils investigated. [ABSTRACT FROM AUTHOR]

The degradation of eight unlabeled highly condensed polycyclic aromatic hydrocarbons (PAH) and the mineralization of three 14C-labeled PAH by the white-rot fungus Pleurotus sp. Florida was investigated. Three concentrations containing 50, 250 or 1250 μg each unlabeled PAH/5 g straw were added to sterile sea sand. Selected treatments were added subsequently with 14C-labeled pyrene, benzo[ a]anthracene or benzo[ a]pyrene. The PAH-loaded sea sand was then mixed into straw substrate and incubated. The disappearance of the unlabeled four-to six-ring PAH: pyrene, benzo[ a]anthracene, chrysene, benzo[ b]fluoranthene, benzo[ k]fluoranthene, benzo[ a]pyrene, dibenz[ a, h]anthracene and benzo[ ghi]perylene, was determined by high-performance liquid chromatography. After 15 weeks of incubation, the recoveries were less than 25% for initial amounts of 50 μg (controls above 85%). The recoveries of unlabeled PAH increased in the inoculated samples with increasing concentrations applied. No correlation could be determined between the number of condensed rings of the PAH and the recoveries of added PAH. Pleurotus sp. Florida mineralized 53% [14C]pyrene, 25% [14C]benzo[ a]anthracene and 39% [14C]benzo[ a]pyrene to 14CO2 in the presence of eight unlabeled PAH (50 μg applied) within 15 weeks. During the course of cultivation, Pleurotus sp. Florida degraded more than 40% of the wheat straw substrate. Variation of the initial concentration of PAH did not influence the extent of degradation of the organic matter. [ABSTRACT FROM AUTHOR]

The potential for reductive dechlorination of hexachlorobenzene was investigated in samples of three different, naturally oxic soils held under conditions of high oxygen deficiency. The soils were water-saturated and the influence on dechlorination of adding different electron donors, a surfactant and an anaerobic microbial consortium was tested. The influence of supplied electron donors seems to depend on the organic matter content of the soils. Dechlorination in the organic-matter-rich soil from Maulach was not affected by amendment with organic electron donors. A release of about 40% chloride within 140 days was observed for this soil in all biotic-treated assays. By contrast, the organic-matter-poor soil of Eppingen showed no dechlorination in unamended assays. However, when it was supplemented with organic electron donors dechlorination of 2%–37% occurred within 140 days, depending on the type of electron donor. Complex substrate (wheat strawdust), from which carbon is slowly liberated, gave the best results. These two soils had an indigenous dechlorinating anaerobic microflora, whereas the third soil (Rastatt) required inoculation with an anaerobic consortium for dechlorination. The addition of electron donors alone did not cause dechlorination in this sandy soil. The addition of a surfactant (Tween 80) to increase the bioavailability of hexachlorobenzene did not enhance dechlorination. This process was not inhibited by inherent alternative electron acceptors in soil (NO3−, SO4 2−, Fe3+). The dechlorination did not require methanogenic conditions. [ABSTRACT FROM AUTHOR]

Summary The immunoprophylactic capacity of specific immune plasma was evaluated in pony foals infected experimentally with Rhodococcus equi. Immune plasma, produced by repeated parenteral administration of viable R. equi to adult horses, was harvested and frozen. Group I (six control foals) and Group II (six principal foals) received lactated Ringers solution and immune plasma respectively at three and five days of age. R. equi were aerosolised into a caudal lung lobe of all foals at seven days of age. Clinical signs, haematological alterations, immune responses, thoracic radiographs and technetium [ABSTRACT FROM AUTHOR]

For KMS-States an inequality between the first and second moment of the time-auto-correlation function is derived and applied to Boson systems to prove that the classical equipartition theorem is strictly non valid. [ABSTRACT FROM AUTHOR]

Pleurotus sp. was grown in liquid medium and on a solid straw substrate, and activities of laccase and manganese-dependent peroxidase (MnP) were recorded. The activities were the highest in a rich, glucose corn-steep liquid medium. In straw cultures, laccase activity was about ten times lower. Under solid state conditions, MnP production was the highest during days 20-40, when laccase activity already had declined. In straw cultures, mineralization ofC-pyrene was measured as release ofCO. The highest rates of pyrene mineralization occurred during days 20-45, i.e. the period of high MnP activities, suggesting a role of this enzyme in PAH degradation. Within 60d, 24% of pyrene was mineralized. [ABSTRACT FROM AUTHOR]

Inequalities between successive moments of the time dependent auto-correlation function are derived. Furthermore, we prove that they provide an infinite set of characterizations of an equilibrium state. [ABSTRACT FROM AUTHOR]

The authors present a simple add on for multicycle, multimJ Ti:sapphire-based amplifier systems to efficiently generate 9.5 fs pulses with 1.8 mJ. Filamentary propagation yields spectrally broadened pulses carrying an unexpected large group-delay dispersion of -500 fs2 which allows linear propagation of the few-cycle pulses towards target areas without need of any sophisticated dispersion control. Pulse compression could easily be achieved by transmission through a combination of different glass substrates. The pulse wave front, the low energy fluctuations, and the good temporal contrast make this source well suited for relativistic laser-solid experiments with intense few-cycle pulses at kilohertz repetition rate. [ABSTRACT FROM AUTHOR]