213 research outputs found

    Congestion Controllers for High Bandwidth Connections with Fiber Error Rates

    Get PDF
    The inefficiency of a TCP connection in the presence of high bandwidth links due to the constant multiplicative decrease factor has been well documented in recent literature. In this paper we look at the effect of fiber error rates on the throughput of a TCP connection. We propose a congestion controller that removes the ill-effects of fiber error rates on TCP throughput by lower bounding the marking probability. We show that this congestion controller can achieve extremely high utilizations in high bandwidth links. We also discuss the TCP friendliness of this congestion controller and present simulation results that validate our analysis

    Sperm morphology in Estonian and Tori Breed Stallions

    Get PDF
    The standard procedure for assessing the breeding potential of a stallion includes the parameter total number of spermatozoa classified as morphologically normal. This study investigated sperm morphology of fresh semen in randomly chosen Estonian (E, n = 8) and Tori (T, n = 7) breed stallions with proven fertility. Two ejaculates were examined from each stallion. An aliquot from each ejaculate was fixed in 1 mL formol-saline immediately after collection and examined with phase-contrast microscope at a magnification 1000× for all types of morphological abnormalities. Furthermore smears were prepared and stained according to Williams (carbolfuchsin-eosin) for a more detailed examination of the sperm heads with light microscope at a magnification 1000×. Analysis of variance was applied to the data, and results are presented as LSmeans (± SE). One T stallion that had a disturbance in the spermatogenesis and one 22-year-old E stallion were not included in the analyses. The T stallions had on average 57.5 ± 4.1% and the E-stallions 74.4 ± 3.8% morphologically normal spermatozoa (p = 0.012). In 4 of 7 T stallions and 7 of 8 E stallions both ejaculates had >50% morphologically normal spermatozoa. There was a significant difference between breeds in mean percentage of proximal droplets (17.3 ± 2.7% and 2.9 ± 2.5% for T and E stallions, respectively; p = 0.003)

    Hydatid cyst of the uterus.

    Get PDF
    BACKGROUND: Hydatidosis is a common zoonosis that affects a large number of humans and animals, especially in poorly developed countries. The infesting parasite has four forms named Echinococcus granulosis, E. multilocularis, E. vogeli and E. oligarthrus (very rare in humans). The most frequently involved organs are liver followed by the lung. The involvement of the genital tract is rare and the occurrence in the uterus is an extreme rarity. We report a case of hydatid cyst in the uterus. CASE: A 70-year-old female with a history of hydatid cysts of the liver, was admitted to hospital after complaining of low abdominal pains. On physical and gynecological examinations, no pathological finding was detected. However, the uterus was significantly large for a postmenopausal patient. Transvaginal sonography (TS) revealed a cystic mass in the uterus with a size of 7 x 6 cm. After further examinations a subtotal hysterectomy was performed. Microscopic examination showed scolices of Echinococcus granulosis. CONCLUSION: Hydatid cysts in the genital tract are rare and the occurrence in the uterus is an extreme rarity. Differentiation between hydatid cyst and malignant disease of the related organ is difficult. To avoid misdiagnosis, a careful examination of pelvic masses should be carried out in endemic areas for detection of hydatid cysts

    Origin of hydrogen fluoride emission in the Orion Bar An excellent tracer for CO-dark H-2 gas clouds

    Get PDF
    Context. The hydrogen fluoride (HF) molecule is seen in absorption in the interstellar medium (ISM) along many lines of sight. Surprisingly, it is observed in emission toward the Orion Bar, which is an interface between the ionized region around the Orion Trapezium stars and the Orion molecular cloud.Aims. We aim to understand the origin of HF emission in the Orion Bar by comparing its spatial distribution with other tracers. We examine three mechanisms to explain the HF emission: thermal excitation, radiative dust pumping, and chemical pumping.Methods. We used a Herschel/HIFI strip map of the HF J = 1 -&gt; 0 line, covering 0.5' by 1.5' that is oriented perpendicular to the Orion Bar. We used the RADEX non-local thermodynamic equilibrium (non-LTE) code to construct the HF column density map. We use the Meudon PDR code to explain the morphology of HF.Results. The bulk of the HF emission at 10 km s(-1) emerges from the CO-dark molecular gas that separates the ionization front from the molecular gas that is deeper in the Orion Bar. The excitation of HF is caused mainly by collisions with H-2 at a density of 10(5) cm(-3) together with a small contribution of electrons in the interclump gas of the Orion Bar. Infrared pumping and chemical pumping are not important.Conclusions. We conclude that the HF J = 1 -&gt; 0 line traces CO-dark molecular gas. Similarly, bright photodissociation regions associated with massive star formation may be responsible for the HF emission observed toward active galactic nuclei.</p

    Protostellar Feedback in Massive Star Forming Regions

    Get PDF
    We examine mechanical feedback mechanisms during the protostellar phase through jets and outflows. To do so, we make use of velocity-resolved CII observations at 158 μ\mum taken with the SOFIA observatory. We identify CII emitting cavities at velocities ranging from 1-2 km s1^{-1} to 15 km s1^{-1} relative to the Veil shell (vLSRv_\mathrm{LSR} = 13 km s1^{-1}). The momentum and dynamical timescales of these cavities imply that the cavities in Orion were formed by fossil and active outflows from stars with luminosities ranging from 103^3 to 105^5 L_\odot. The momentum deposited during protostellar feedback is \sim1/6 of the momentum of the Veil shell deposited through winds from θ1\theta^1 Ori C. By creating cavities, the fossil outflows may already have broken the Veil shell, and outflows from less massive stars may have made the Veil shell porous

    Search for radio jets from massive young stellar objects. Association of radio jets with H<sub>2</sub>O and CH<sub>3</sub>OH masers

    Get PDF
    Context. Recent theoretical and observational studies debate the similarities of the formation process of high- (>8 M⊙) and low-mass stars. The formation of low-mass stars is directly associated with the presence of disks and jets. Theoretical models predict that stars with masses up to 140 M⊙ can be formed through disk-mediated accretion in disk-jet systems. According to this scenario, radio jets are expected to be common in high-mass star-forming regions. Aims. We aim to increase the number of known radio jets in high-mass star-forming regions by searching for radio-jet candidates at radio continuum wavelengths. Methods. We used the Karl G. Jansky Very Large Array (VLA) to observe 18 high-mass star-forming regions in the C band (6 cm, ≈1′′.0 resolution) and K band (1.3 cm, ≈0′′.3 resolution). We searched for radio-jet candidates by studying the association of radio continuum sources with shock activity signs (e.g., molecular outflows, extended green objects, and maser emission). Our VLA observations also targeted the 22 GHz H2O and 6.7 GHz CH3OH maser lines. Results. We have identified 146 radio continuum sources, 40 of which are located within the field of view of both images (C and K band maps). We derived the spectral index, which is consistent with thermal emission (between − 0.1 and + 2.0) for 73% of these sources. Based on the association with shock-activity signs, we identified 28 radio-jet candidates. Out of these, we identified 7 as the most probable radio jets. The radio luminosity of the radio-jet candidates is correlated with the bolometric luminosity and the outflow momentum rate. About 7–36% of the radio-jet candidates are associated with nonthermal emission. The radio-jet candidates associated with 6.7 GHz CH3OH maser emission are preferentially thermal winds and jets, while a considerable fraction of radio-jet candidates associated with H2O masers show nonthermal emission that is likely due to strong shocks. Conclusions. About 60% of the radio continuum sources detected within the field of view of our VLA images are potential radio jets. The remaining sources could be compact H I

    Robustness of Massively Parallel Sequencing Platforms

    Get PDF
    The improvements in high throughput sequencing technologies (HTS) made clinical sequencing projects such as ClinSeq and Genomics England feasible. Although there are significant improvements in accuracy and reproducibility of HTS based analyses, the usability of these types of data for diagnostic and prognostic applications necessitates a near perfect data generation. To assess the usability of a widely used HTS platform for accurate and reproducible clinical applications in terms of robustness, we generated whole genome shotgun (WGS) sequence data from the genomes of two human individuals in two different genome sequencing centers. After analyzing the data to characterize SNPs and indels using the same tools (BWA, SAMtools, and GATK), we observed significant number of discrepancies in the call sets. As expected, the most of the disagreements between the call sets were found within genomic regions containing common repeats and segmental duplications, albeit only a small fraction of the discordant variants were within the exons and other functionally relevant regions such as promoters. We conclude that although HTS platforms are sufficiently powerful for providing data for first-pass clinical tests, the variant predictions still need to be confirmed using orthogonal methods before using in clinical applications
    corecore