Frequency-Dependent Squeezed Vacuum Source for the Advanced Virgo Gravitational-Wave Detector

In this Letter, we present the design and performance of the frequency-dependent squeezed vacuum source that will be used for the broadband quantum noise reduction of the Advanced Virgo Plus gravitational-wave detector in the upcoming observation run. The frequency-dependent squeezed field is generated by a phase rotation of a frequency-independent squeezed state through a 285 m long, high-finesse, near-detuned optical resonator. With about 8.5 dB of generated squeezing, up to 5.6 dB of quantum noise suppression has been measured at high frequency while close to the filter cavity resonance frequency, the intracavity losses limit this value to about 2 dB. Frequency-dependent squeezing is produced with a rotation frequency stability of about 6 Hz rms, which is maintained over the long term. The achieved results fulfill the frequency dependent squeezed vacuum source requirements for Advanced Virgo Plus. With the current squeezing source, considering also the estimated squeezing degradation induced by the interferometer, we expect a reduction of the quantum shot noise and radiation pressure noise of up to 4.5 dB and 2 dB, respectively.

Exercise-induced HSP27, HSP70 and MAPK responses in human skeletal muscle

AIM

The present work examined protein and messenger RNA (mRNA) expression of intramuscular heat shock protein 27 (HSP27), heat shock cognate (HSC70) and HSP70 in human biceps brachii (BB) and vastus lateralis (VL) subsequent to two different exercises.

METHODS

Untrained subjects performed 50 high-force eccentric contractions with their non-dominant BB and ran downhill (-10 degrees) for 30 min. The 48-h PX stress response was evaluated with immunoblotting and reverse transcriptase-polymerase chain reaction (RT-PCR). Muscle damage was indicated indirectly at 48 h post-exercise (PX) [loss of mobility, muscle soreness and serum creatine kinase (CK) activity].

RESULTS

On the protein level, HSP27 and HSP70 increased significantly PX in the BB (384 and 227%, respectively; P < 0.01), but there were no significant HSP changes in the VL or in HSC70 in either muscle. The RT-PCR data complemented these findings: BB HSP27 and HSP70C mRNA levels increased (135 and 128%, respectively; P < 0.05); in the VL only HSP70B increased (206%; P < 0.05). Phosphorylation of e-jun NH2-terminal kinase (JNK) and extracellular regulated kinase (ERK) increased significantly in the BB (226 and 200%, respectively; P < 0.05) but not in the VL, indicating activation of these pathways only after the resistance exercise.

CONCLUSION

These data indicate that the PX HSP and mitogen-activated protein kinase responses are exercise-specific and local, not systemic. Further, only the resistance exercise induced HSP expression (protein and mRNA) and JNK/ERK activation at 48 h PX, suggesting that these molecules may be important to long-term skeletal muscle adaptations such as hypertrophy.

Measuring the top Yukawa coupling to a heavy Higgs Boson at future e(+)e(-) linear colliders

If the Higgs boson mass is greater than 350 GeV, the top quark Yukawa coupling can be determined using the Higgs resonant contribution to t&tmacr; production from W+W- fusion at high energy e(+)e(-) linear colliders. We have evaluated the significance with which the signal of a Higgs decaying to t&tmacr; pairs could be observed at future e(+)e(-) colliders, with center of mass energies of 800 GeV and 1 TeV, and an integrated luminosity of 1 ab(-1). We find that a signal significance greater than 5sigma and a relative error in the top Yukawa measurement better than 10% can be achieved at these facilities, for Higgs boson masses in the ranges of 350-500 GeV and 350-650 GeV, respectively.

Plasma levels of diphenylhydantoin and the control of adult epileptic seizures: a Chilean experience

In a prospective study of 117 adult ambulatory patients, 110 of whom were epileptics treated only with oral diphenylhydantoin (DPH), plasma levels of this drug were determined by gas-liquid chromatography. The average follow-up time was 6 months (range, 3 to 13 months); satisfactory control of seizures was obtained with plasma levels in the 10.2 to 25.8 micrograms/ml range, representing 68% of the patients whose seizures had been controlled. The dosage received by this group was from 4.2 to 6 mg/kg, with an average of 5.1. In general, these results agree with those found in European or North American patients, even though some differences or little clarity in the methodology of other trials make comparison difficult. This similarity of results makes one think that genetic or environmental differences do not alter the response to DPH in our patients, but further studies are necessary in that area. This paper can serve as a basis for the extrapolation of data about DPH coming from other latitudes that have been considered supposedly valid for Latin American epileptic patients.