Measurements and Code Comparison of Wave Dispersion and Antenna Radiation Resisitance for Helicon Waves in a High Density Cylindrical Plasma Source

Helicon wave dispersion and radiation resistance measurements in a high density (ne ≈ 1019 - 1020m-3) and magnetic field (B < 0.2 T) cylindrical plasma source are compared to the results of a recently developed numerical plasma wave code [I. V. Kamensk

Искажение спектра сигнала протяженной цели в радаре с непрерывным частотно-модулированным сигналом

The problem of spectrum distortion in radar with a continuous frequency modulated signal (FMCW radar) is considered in the case of locating extended targets containing a large number of closely spaced reflection points. An extended target model is introduced for which a beat signal is analyzed based on its representation in the form of an amplitude-modulated oscillation. It is shown that the distortion of the spectrum occurs due to a certain relationship between the distances of the target points, the values of the carrier frequency and the deviation of the probe signal frequency. The results of numerical calculations for various values of the signal parameters and the long target model are given.En el presente artículo se aborda el problema de la distorsión del espectro en radares con señal continua de frecuencia modulada (radar FMCW) al producir objetivos prolongados que contienen un gran número de puntos de reflexión cercanos. El documento introduce un modelo de objetivo extendido para el cual se realiza un análisis de la señal de los latidos en función de su presentación en forma de oscilación de amplitud modulada. Este estudio muestra que la distorsión del espectro se produce como resultado de ciertas relaciones entre las distancias de los puntos de destino, los valores de frecuencia portadora y la frecuencia de desviación de la señal de sondeo. El artículo presenta los resultados de los cálculos numéricos para los diferentes valores de los parámetros de la señal y el modelo de objetivo extendido.No presente artigo, o problema da distorção do espectro em radares com sinal de frequência modulada contínua (radar FMCW) é abordado ao produzir objetivos prolongados que contêm um grande número de pontos de reflexão próximos. O documento introduz um modelo objetivo estendido para o qual uma análise do sinal de batimentos cardíacos é realizada de acordo com sua apresentação na forma de uma oscilação de amplitude modulada. Este estudo mostra que a distorção do espectro ocorre como resultado de certas relações entre as distâncias dos pontos de destino, os valores da freqüência da portadora e a freqüência do desvio do sinal sonoro. O artigo apresenta os resultados dos cálculos numéricos para os diferentes valores dos parâmetros do sinal e do modelo objetivo estendido.Рассмотрена проблема искажения спектра в радаре с непрерывным частотно-модулированным сигналом (FMCW радаре) при лоцировании протяженных целей, содержащих большое число близкорасположенных точек отражения. Введена модель протяженной цели, для которой проведен анализ сигнала биений на основе представления его в виде амплитудно-модулированного колебания. Показано, что искажение спектра возникает в результате определенных соотношений между расстояниями точек цели, значениями несущей частоты и частоты девиации зондирующего сигнала. Приведены результаты численных расчетов для различных значений параметров сигнала и модели протяженной цели

Process pi p -> pi pi N at high energies and moderate momenta transferred to the nucleon and the determination of parameters of the f_0(980) and f_0(1300)

We present the results of simultaneous analysis of the S-wave pi pi-spectra in the reactions pi^- p -> (pi^0 pi^0)_S n at p_{lab}=38 GeV/c (GAMS) and pi^- p -> (pi^+ pi^-)_S n at p_{lab}=18 GeV/c (E852 Collaboration) at moderate momenta transferred to the nucleon, |t| < 1.5 (GeV/c)^2. The t-distributions are described by the reggeized pi- and a_1-exchanges provided by the leading and daughter trajectories, while the M_{pi pi}-spectra are determined by a set of scalar-isoscalar resonances. With M_{pi pi}-distributions averaged over t-intervals, we have found several solutions given by different t-channel exchange mechanisms at |t| ~ (0.5-1.5) (GeV/c)^2, with resonance parameters close to each other. We conclude that despite a poor knowledge of the structure of the t-exchange, the characteristics of resonances such as masses and widths can be reliably determined using the processes under discussion. As to pole positions, we have found (1031 +/- 10) - i(35 +/- 6) MeV for f_0(980) and (1315 +/- 20) - i(150 +/- 30) MeV for f_0(1300).Comment: 17 pages, RevTeX, 10 EPS figures, misprints correcte

Observation of the Cabibbo-suppressed decay Xi_c+ -> p K- pi+

We report the first observation of the Cabibbo-suppressed charm baryon decay Xi_c+ -> p K- pi+. We observe 150 +- 22 events for the signal. The data were accumulated using the SELEX spectrometer during the 1996-1997 fixed target run at Fermilab, chiefly from a 600 GeV/c Sigma- beam. The branching fractions of the decay relative to the Cabibbo-favored Xi_c+ -> Sigma+ K- pi+ and Xi_c+ -> X- pi+ pi+ are measured to be B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> Sigma+ K- pi+) = 0.22 +- 0.06 +- 0.03 and B(Xi_c+ -> p K- pi+)/B(Xi_c+ -> X- pi+ pi+) = 0.20 +- 0.04 +- 0.02, respectively.Comment: 5 pages, RevTeX, 3 figures (postscript), Submitted to Phys. Rev. Let

Mitochondrial Lysyl-tRNA Synthetase Independent Import of tRNA Lysine into Yeast Mitochondria

Aminoacyl tRNA synthetases play a central role in protein synthesis by charging tRNAs with amino acids. Yeast mitochondrial lysyl tRNA synthetase (Msk1), in addition to the aminoacylation of mitochondrial tRNA, also functions as a chaperone to facilitate the import of cytosolic lysyl tRNA. In this report, we show that human mitochondrial Kars (lysyl tRNA synthetase) can complement the growth defect associated with the loss of yeast Msk1 and can additionally facilitate the in vitro import of tRNA into mitochondria. Surprisingly, the import of lysyl tRNA can occur independent of Msk1 in vivo. This suggests that an alternative mechanism is present for the import of lysyl tRNA in yeast

A Deubiquitylating Complex Required for Neosynthesis of a Yeast Mitochondrial ATP Synthase Subunit

The ubiquitin system is known to be involved in maintaining the integrity of mitochondria, but little is known about the role of deubiquitylating (DUB) enzymes in such functions. Budding yeast cells deleted for UBP13 and its close homolog UBP9 displayed a high incidence of petite colonies and slow respiratory growth at 37°C. Both Ubp9 and Ubp13 interacted directly with Duf1 (DUB-associated factor 1), a WD40 motif-containing protein. Duf1 activates the DUB activity of recombinant Ubp9 and Ubp13 in vitro and deletion of DUF1 resulted in the same respiratory phenotype as the deletion of both UBP9 and UBP13. We show that the mitochondrial defects of these mutants resulted from a strong decrease at 37°C in the de novo biosynthesis of Atp9, a membrane-bound component of ATP synthase encoded by mitochondrial DNA. The defect appears at the level of ATP9 mRNA translation, while its maturation remained unchanged in the mutants. This study describes a new role of the ubiquitin system in mitochondrial biogenesis

Enhanced killing of androgen-independent prostate cancer cells using inositol hexakisphosphate in combination with proteasome inhibitors

Effective treatments for androgen-independent prostate cancer (AIPCa) are lacking. To address this, emerging therapeutics such as proteasome inhibitors are currently undergoing clinical trials. Inositol hexakisphosphate (IP6) is an orally non-toxic phytochemical that exhibits antitumour activity against several types of cancer including PCa. We have previously shown that treatment of PC3 cells with IP6 induces the transcription of a subset of nuclear factor-κB (NF-κB)-responsive and pro-apoptotic BCL-2 family genes. In this study, we report that although NF-κB subunits p50/p65 translocate to the nucleus of PC3 cells in response to IP6, inhibition of NF-κB-mediated transcription using non-degradable inhibitor of κB (IκB)-α does not modulate IP6 sensitivity. Treatment with IP6 also leads to increased protein levels of PUMA, BIK/NBK and NOXA between 4 and 8 h of treatment and decreased levels of MCL-1 and BCL-2 after 24 h. Although blocking transcription using actinomycin D does not modulate PC3 cell sensitivity to IP6, inhibition of protein translation using cycloheximide has a significant protective effect. In contrast, blocking proteasome-mediated protein degradation using MG-132 significantly enhances the ability of IP6 to reduce cellular metabolic activity in both PC3 and DU145 AIPCa cell lines. This effect of combined treatment on mitochondrial depolarisation is particularly striking and is also reproduced by another proteasome inhibitor (ALLN). The enhanced effect of combined MG132/IP6 treatment is almost completely inhibited by cycloheximide and correlates with changes in BCL-2 family protein levels. Altogether these results suggest a role for BCL-2 family proteins in mediating the combined effect of IP6 and proteasome inhibitors and warrant further pre-clinical studies for the treatment of AIPCa