4,317 research outputs found
Progress on pricing with peering
This paper examines a simple model of how a
provider ISP charges customer ISPs by assuming the provider
ISP wants to maximize its revenue when customer ISPs have
the possibility of setting up peering connections. It is shown that
finding the optimal pricing is NP-complete, and APX-complete.
Customers can respond to price in many ways, including throttling
traffic as well as peering. An algorithm is studied which
obtains a 1/4 approximation for a wide range of customer
responses
Removal of reactive dyes by quaternized coconut husk
Coconut husk modified through the use of N-(3-chloro-2-hydroxypropyl)- trimethylammonium chloride was evaluated for its ability to remove reactive dyes from aqueous solution. Sorption of dyes was pH dependent and favorable sorption occurred at low pH. In contrast, natural coconut husk showed very little uptake of these reactive dyes. The maximum sorption capacities of the modified coconut husks for Reactive Blue 2, Reactive Yellow 2, Reactive Orange 16 and Reactive Blue 4 were 128.9, 182.2, 254.5 and 423.7 mg/g respectively. Column experiments using textile effluent showed that the reactive and disperse dyes in the effluent could be successfully removed
Stereotactic MRI-guided Adaptive Radiation Therapy (SMART) for Locally Advanced Pancreatic Cancer: A Promising Approach.
Locally advanced pancreatic cancer (LAPC) is characterized by poor prognosis and low response durability with standard-of-care chemotherapy or chemoradiotherapy treatment. Stereotactic body radiation therapy (SBRT), which has a shorter treatment course than conventionally fractionated radiotherapy and allows for better integration with systemic therapy, may confer a survival benefit but is limited by gastrointestinal toxicity. Stereotactic MRI-guided adaptive radiation therapy (SMART) has recently gained attention for its potential to increase treatment precision and thus minimize this toxicity through continuous real-time soft-tissue imaging during radiotherapy. The case presented here illustrates the promising outcome of a 69-year-old male patient with LAPC treated with SMART with daily adaptive planning and respiratory-gated technique
Enhancement of Copper Sorption through Acid Blue 29 Treated Oil Palm Pressed Fibres
The removal of cupric ions from aqueous solution by natural and dyecoated palm pressed fibres was studied. Sorption was both pH and concentration dependent. The equilibrium data followed the Langmuir isotherm model with maximum copper sorption capacities of 2.41 and 7.71 mg/g for natural and dye-treated fibres respectively. The presence of
other metal ions inhibited copper uptake in the following order Pb> Zn > Ni. The suppressing effects of chelators correspond to their log K values. Column studies showed that bed-depth had a more pronounced
effect on copper sorption than flow rate
Binding of Basic Dyes by the Algae, Chara aspera
Non-living biomass of the algae Chara aspera is capable of binding two basic dyes, methylene blue and basic blue 3, from aqueous solution. Factors such as dye concentration, contact time, sorbent dosage and pH of solution were
studied. Maximum sorption capacities of the algae for methylene blue and basic blue 3 are 139.4 and 17.8 mg/g, respectively, as determined from the
Langmuir isothenns
Stereotactic Magnetic Resonance-guided Online Adaptive Radiotherapy for Oligometastatic Breast Cancer: A Case Report.
We present a case of durable local control achieved in a patient treated with stereotactic magnetic resonance-guided adaptive radiation therapy (SMART) for an abdominal lymph node in the setting of oligometastatic breast cancer. A 50-year-old woman with a history of triple positive metastatic invasive ductal carcinoma of the left breast, stage IV (T3N2M1), underwent neoadjuvant chemotherapy, mastectomy, adjuvant radiotherapy and maintenance hormonal treatment with HER2 targeted therapies. At 20 months after definitive treatment of her primary, imaging showed an isolated progressive enlargement of lymph nodes between hepatic segment V/IVB and the neck of the pancreas. Radiofrequency ablation was considered, however, this approach was decided not to be optimal due to the proximity to stomach, and pancreatic duct. The patient was treated with SMART for 40 Gray in 5 fractions. Two and a half years later, the patient remains without evidence of disease progression. She experienced Grade 2 acute and late toxicity that was successfully managed with medications. This experience shows that SMART is a feasible and effective treatment to control the abdominal oligometastatic disease for breast cancer
Prevalence of musculoskeletal injuries among young squash players in Malaysia
The aim of the study was to investigate the prevalence of musculoskeletal injuries sustained by young squash players in Malaysia. This study was conducted retrospectively by usingStandardized Nordic Questionnaire (NSQ) during SUKMA 2016 at Kuching, Sarawak, Malaysia. The questionnaires were distributed to the squash players after getting the approval from the authorities. Totally 94 questionnaires were distributed and 60 questionnaires (62.5%) were returned with completed answers. The mean age of the respondents were 17.58 ± 3.042 years with 8.85 ± 3.013 years of experience of playing squash. Among the respondents 83.33% were reported that they had musculoskeletal problems during last 12 months. The wrist and hand were the area with the highest (31.7%) prevalence of musculoskeletal symptoms, and the elbow with least (8.3%) prevalence among the respondents.Key Words: Squash, musculoskeletal, injury, survey, evaluatio
High-Lundquist Number Scaling in Three-Dimensional Simulations of Parker's Model of Coronal Heating
Parker's model is one of the most discussed mechanisms for coronal heating
and has generated much debate. We have recently obtained new scaling results in
a two-dimensional (2D) version of this problem suggesting that the heating rate
becomes independent of resistivity in a statistical steady state [Ng and
Bhattacharjee, Astrophys. J., 675, 899 (2008)]. Our numerical work has now been
extended to 3D by means of large-scale numerical simulations. Random
photospheric footpoint motion is applied for a time much longer than the
correlation time of the motion to obtain converged average coronal heating
rates. Simulations are done for different values of the Lundquist number to
determine scaling. In the high-Lundquist number limit, the coronal heating rate
obtained so far is consistent with a trend that is independent of the Lundquist
number, as predicted by previous analysis as well as 2D simulations. In the
same limit the average magnetic energy built up by the random footpoint motion
tends to have a much weaker dependence on the Lundquist number than that in the
2D simulations, due to the formation of strong current layers and subsequent
disruption when the equilibrium becomes unstable. We will present scaling
analysis showing that when the dissipation time is comparable or larger than
the correlation time of the random footpoint motion, the heating rate tends to
become independent of Lundquist number, and that the magnetic energy production
is also reduced significantly.Comment: Accepted for publication in Astrophysical Journa
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Online Adaptive Radiation Therapy: Implementation of a New Process of Care.
Onboard magnetic resonance imaging (MRI) guided radiotherapy is now clinically available in nine centers in the world. This technology has facilitated the clinical implementation of online adaptive radiotherapy (OART), or the ability to alter the daily treatment plan based on tumor and anatomical changes in real-time while the patient is on the treatment table. However, due to the time sensitive nature of OART, implementation in a large and busy clinic has many potential obstacles as well as patient-related safety considerations. In this work, we have described the implementation of this new process of care in the Department of Radiation Oncology at the University of California, Los Angeles (UCLA). We describe the rationale, the initial challenges such as treatment time considerations, technical issues during the process of re-contouring, re-optimization, quality assurance, as well as our current solutions to overcome these challenges. In addition, we describe the implementation of a coverage system with a physician of the day as well as online planners (physicists or dosimetrists) to oversee each OART treatment with patient-specific 'hand-off' directives from the patient's treating physician. The purpose of this effort is to streamline the process without compromising treatment quality and patient safety. As more MRI-guided radiotherapy programs come online, we hope that our experience can facilitate successful adoption of OART in a way that maximally benefits the patient
Ginseng and Ginkgo Biloba effects on cognition as modulated by cardiovascular reactivity: A randomised trial
Background
There is some evidence to suggest that ginseng and Ginkgo biloba can improve cognitive performance, however, very little is known about the mechanisms associated with such improvement. Here, we tested whether cardiovascular reactivity to a task is associated with cognitive improvement.
Methodology/Principal findings
Using a double-blind, placebo controlled, crossover design, participants (N = 24) received two doses of Panax Ginseng (500, 1000 mg) or Ginkgo Biloba (120, 240 mg) (N = 24), and underwent a series of cognitive tests while systolic, diastolic, and heart rate readings were taken. Ginkgo Biloba improved aspects of executive functioning (Stroop and Berg tasks) in females but not in males. Ginseng had no effect on cognition. Ginkgo biloba in females reversed the initial (i.e. placebo) increase in cardiovascular reactivity (systolic and diastolic readings increased compared to baseline) to cognitive tasks. This effect (reversal) was most notable after those tasks (Stroop and Iowa) that elicited the greatest cardiovascular reactivity during placebo. In males, although ginkgo also decreased cardiovascular readings, it did so from an initial (placebo) blunted response (i.e. decrease or no change from baseline) to cognitive tasks. Ginseng, on the contrary, increased cardiovascular readings compared to placebo.
Conclusions/Significance
These results suggest that cardiovascular reactivity may be a mechanism by which ginkgo but not ginseng, in females is associated with certain forms of cognitive improvement
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