517 research outputs found
Measuring and Understanding Throughput of Network Topologies
High throughput is of particular interest in data center and HPC networks.
Although myriad network topologies have been proposed, a broad head-to-head
comparison across topologies and across traffic patterns is absent, and the
right way to compare worst-case throughput performance is a subtle problem.
In this paper, we develop a framework to benchmark the throughput of network
topologies, using a two-pronged approach. First, we study performance on a
variety of synthetic and experimentally-measured traffic matrices (TMs).
Second, we show how to measure worst-case throughput by generating a
near-worst-case TM for any given topology. We apply the framework to study the
performance of these TMs in a wide range of network topologies, revealing
insights into the performance of topologies with scaling, robustness of
performance across TMs, and the effect of scattered workload placement. Our
evaluation code is freely available
cISP: A Speed-of-Light Internet Service Provider
Low latency is a requirement for a variety of interactive network
applications. The Internet, however, is not optimized for latency. We thus
explore the design of cost-effective wide-area networks that move data over
paths very close to great-circle paths, at speeds very close to the speed of
light in vacuum. Our cISP design augments the Internet's fiber with free-space
wireless connectivity. cISP addresses the fundamental challenge of
simultaneously providing low latency and scalable bandwidth, while accounting
for numerous practical factors ranging from transmission tower availability to
packet queuing. We show that instantiations of cISP across the contiguous
United States and Europe would achieve mean latencies within 5% of that
achievable using great-circle paths at the speed of light, over medium and long
distances. Further, we estimate that the economic value from such networks
would substantially exceed their expense
Evaluation of heavy metal uptake and translocation by Acacia mangium as a phytoremediator of copper contaminated soil
Many organic and inorganic pollutants, including heavy metals are being transported and mixed with the cultivated soils and water. Heavy metals are the most dangerous pollutants as they are nondegradable and accumulate and become toxic to plants and animals. An experiment was conducted in the glasshouse to evaluate the potential of Acacia mangium as a phytoremediator to absorb heavy metals from contaminated soils. A. mangium seedlings were planted in the growth media (soil + different levels of copper). The different levels of Cu were: T0 (control, soil), T1 (50 ppm Cu), T2 (100 ppm Cu), T3 (200 ppm Cu), T4 (300 ppm Cu) and T5 (400 ppm Cu). The highest growth performance such as basal diameter, height and number of leaves was in T1. The highest biomass was recorded in T1. Highest accumulation of Cu (93.55 ppm) and Zn (79.13 ppm) were recorded in T5 while Cd (8.88 ppm) in T3. Cu was highly concentrated in the roots, Cd was accumulated in the leaves and roots, whereas, Zn was in stems and leaves. A. mangium showed high translocation factor (TF) and low bioconcentration factor (BCF) values in soil at higher metal concentrations as well as it was able to tolerate and accumulate high concentrations of Cd, Cu and Zn. It may be concluded that this species can be a good efficient phtyoremediator for heavy metals (Cd, Cu and Zn) contaminated soils to mitigate soil pollution.Key words: Heavy metals, phytoremediation, bioaccumulation capacity
Penentuan Korelasi Perubahan Kecepatan Angin dan Kekuatan Radiasi terhadap Ketinggian Lapisan Inversi dan Hubungannya dengan Kualitas Udara Ambien Kota Surabaya
Dispersi polutan pada udara ambien dipengaruhi oleh ketinggian lapisan inversi yang membatasi ruang mixing height di Kota Surabaya. Ketinggian lapisan inversi dipengaruhi oleh faktor meteorologi dan kestabilan atmosfer di suatu daerah. Tujuan dari penelitian ini adalah untuk menganalisis hubungan Perubahan kecepatan angin dan kekuatan radiasi terhadap ketinggian lapisan inversi dan kualitas udara ambien di Kota Surabaya. Metode yang digunakan untuk analisis korelasi dalam penelitian ini adalah metode korelasi Pearson. Data ketinggian lapisan inversi didapatkan dari profil temperatur terhadap ketinggian hasil pengukuran radiosonde BMKG Juanda pada tahun 2009 hingga 2014. Analisis korelasi yang dilakukan diasumsikan dalam keadaan normal sehingga data yang digunakan adalah data hasil pelingkupan pada pukul 00.00 WIB dan 12.00 WIB dengan nilai persentil 10% dari tahun 2009 hingga 2014. Lapisan inversi pada Kota Surabaya kemungkinan merupakan lapisan subsidence inversion. Lapisan inversi tersebut memiliki korelasi berbanding terbalik pada pukul 00.00 WIB dan korelasi berbanding lurus pada pukul 12.00 WIB terhadap kecepatan angin, sedangkan untuk kekuatan radiasi tidak berkorelasi. Korelasi ketinggian lapisan inversi dengan kualitas udara ambien SO2 berbanding terbalik, namun tidak berkorelasi dengan NO2 dan O3
Congenital dislocation of knee: A correctable deformity
We report the case of a late preterm small for gestational age baby girl presenting with deformities of both knees at birth. Diagnosisby radiologic investigation revealed bilateral knee joint dislocation and ultrasonography revealed developmental dysplasia of thehip. Concomitant treatment of the congenital dislocation of the knee with serial casting and the hip with Pavlik harness providedsatisfactory results. Cases with delayed presentation or which do not respond to conservative treatment need surgery. Delay intreatment may lead to long-term instability and stiffness. Emphasis should be laid on the immediate recognition and treatment ofthe condition
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Identification and Density Estimation of American Martens (Martes americana) Using a Novel Camera-Trap Method
Camera-traps are increasingly used to estimate wildlife abundance, yet few studies exist for small-sized carnivores or comparing efficacy against traditional methods. We developed a camera-trap to identify the unique ventral patches of American martens (Martes americana). Our method was designed to: (1) determine the optimal trap configuration to photograph ventral patches; (2) evaluate the use of temporally clustered photographs to determine independence and improve identification; and (3) determine factors that influence identification probability. We tested our method by comparing camera- and live-trap density estimates using spatial capture–recapture (SCR) models. The ventral patches of radio-collared martens were most visible when traps were placed 15–20 cm above a feeding platform. Radio-collared martens (n = 14) visited camera-traps for long periods (median = 7 min) with long intervals between visits (median = 419 min), and visits by different martens at the same trap \u3c15 min apart was infrequent (n = 3) during both years. Similarly, there was complete agreement among observers that clustered photos of un-collared martens were always of the same individual. Pairwise agreement was high between observers; eight un-collared martens were identifiable by consensus on 90% (54 of 60) of recorded visits. Factors influencing identification probability were directly related to the time martens spent feeding at traps (β = 0.143, P = 0.01) and inversely proportional to the time that elapsed since traps were baited (β = −0.344, P = 0.006). Density estimates were higher and more precise for camera-trapping (0.60, 0.35–1.01 martens/km2) than live-trapping (0.45, 0.16–1.22 martens/km2), providing evidence that SCR density estimates may be biased when capture heterogeneity is present, yet cannot be accounted for due to small sample size. Our camera-trap method provides a minimally invasive and accurate tool for monitoring marten populations
One-Pot Synthesis of 5,6-Dihydro-4H-1,2-Oxazines by Cyclization of Ketoximes with Derivatives of Allylbenzene
A new series of 5,6-dihydro-4H-1,2-oxazines were synthesized via hetero Diels-Alder reaction of α-nitrosolefins with derivatives of allylbenzene. α-Nitrosoolefins were generated from ketoximes by the action of chloramine-T and triethylamine
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