Multi-Commodity Flow with In-Network Processing

Modern networks run "middleboxes" that offer services ranging from network address translation and server load balancing to firewalls, encryption, and compression. In an industry trend known as Network Functions Virtualization (NFV), these middleboxes run as virtual machines on any commodity server, and the switches steer traffic through the relevant chain of services. Network administrators must decide how many middleboxes to run, where to place them, and how to direct traffic through them, based on the traffic load and the server and network capacity. Rather than placing specific kinds of middleboxes on each processing node, we argue that server virtualization allows each server node to host all middlebox functions, and simply vary the fraction of resources devoted to each one. This extra flexibility fundamentally changes the optimization problem the network administrators must solve to a new kind of multi-commodity flow problem, where the traffic flows consume bandwidth on the links as well as processing resources on the nodes. We show that allocating resources to maximize the processed flow can be optimized exactly via a linear programming formulation, and to arbitrary accuracy via an efficient combinatorial algorithm. Our experiments with real traffic and topologies show that a joint optimization of node and link resources leads to an efficient use of bandwidth and processing capacity. We also study a class of design problems that decide where to provide node capacity to best process and route a given set of demands, and demonstrate both approximation algorithms and hardness results for these problems

An Unusual Presentation of a Mixed Epithelial and Stromal Tumor in an Elderly Male

Mixed epithelial and stromal tumors (MESTs) of the kidney are rare renal neoplasms characterized by mixed cystic and solid components. These tumors are typically present in middle-aged women as a flank mass, or as a cause of flank pain or hematuria. We outline the case of an older male who presented with an enlarging abdominal mass causing symptoms that suggested a partial small bowel obstruction. Management of the patient and a brief review are discussed

A 55-Year-Old Man with Stage IV Squamous Cell Carcinoma of the Right Groin after External Beam Radiation for Testicular Cancer

Treating testicular cancer with adjuvant radiation has been associated with a number of second malignancies affecting the genitourinary tract and retroperitoneal structures; however, there have been few reported cases of cutaneous second malignancies. We report the case of a man who developed stage IV squamous cell carcinoma (SCC) of a condyloma after orchiectomy and adjuvant radiation for testicular cancer. We also review relevant literature available to date. A 55-year-old Caucasian man presented to the hospital with a large growth at the right groin which had grown into his right thigh preventing ambulation. His past medical history was significant for right testicular cancer of unknown pathology treated with orchiectomy and adjuvant radiation twenty years ago. Punch biopsy of the lesion revealed superficially invasive squamous cell carcinoma. He underwent excision of the growth with subsequent Cisplatin, radiation boost, and Paclitaxel regimens. Despite an aggressive treatment regimen and an initial good response, the patient’s cancer progressed requiring palliative care. It is unclear whether or not therapeutic radiation in this case promoted the conversion of the patient’s condyloma to a malignant lesion. Further studies are required at this time to clarify the clinical implications of these findings

Evaluation of an epigenetic assay for predicting repeat prostate biopsy outcome in African American men

OBJECTIVE: To evaluate an epigenetic assay performed on tissue from negative prostate biopsies in a group of African American (AA) men undergoing repeat biopsy, and to compare accuracy for predicting repeat biopsy outcome to prior studies conducted in predominantly Caucasian populations. MATERIALS AND METHODS: The study population consisted of 211 AA men from 7 urology centers across the United States; all of whom were undergoing 12-core transrectal ultrasound-guided repeat biopsy within 30 months from a negative index biopsy. All biopsy cores from the negative index biopsy were profiled for the epigenetic biomarkers GSTP1, APC, and RASSF1 using ConfirmMDx for Prostate Cancer (MDxHealth, Irvine, CA). RESULTS: Upon repeat biopsy, 130 of 211 subjects (62%) had no prostate cancer (PCa) detected and 81 of 211 (38%) were diagnosed with PCa. Of the subjects with PCa, 54 (67%) were diagnosed with Gleason score (GS) = 7 disease. For detection of PCa at repeat biopsy, ConfirmMDx sensitivity was 74.1% and specificity was 60.0%, equivalent to prior studies (P = .235 and .697, respectively). For detection of GS >= 7 PCa, sensitivity was 78% and specificity was 53%. The negative predictive values for detection of all PCa and GS >= 7 PCa were 78.8% and 94.2%, respectively. CONCLUSION: In this group of AA men, we successfully validated an epigenetic assay to assess the need for repeat biopsy. Results were consistent with previous studies from predominantly Caucasian populations. Therefore, the ConfirmMDx assay is a useful tool for risk stratification of AA men who had an initial negative biopsy

Towards a coordinated strategy for intercepting human disease emergence in Africa

Non peer reviewe

High aboveground carbon stock of African tropical montane forests

Tropical forests store 40-50 per cent of terrestrial vegetation carbon(1). However, spatial variations in aboveground live tree biomass carbon (AGC) stocks remain poorly understood, in particular in tropical montane forests(2). Owing to climatic and soil changes with increasing elevation(3), AGC stocks are lower in tropical montane forests compared with lowland forests(2). Here we assemble and analyse a dataset of structurally intact old-growth forests (AfriMont) spanning 44 montane sites in 12 African countries. We find that montane sites in the AfriMont plot network have a mean AGC stock of 149.4 megagrams of carbon per hectare (95% confidence interval 137.1-164.2), which is comparable to lowland forests in the African Tropical Rainforest Observation Network(4) and about 70 per cent and 32 per cent higher than averages from plot networks in montane(2,5,6) and lowland(7) forests in the Neotropics, respectively. Notably, our results are two-thirds higher than the Intergovernmental Panel on Climate Change default values for these forests in Africa(8). We find that the low stem density and high abundance of large trees of African lowland forests(4) is mirrored in the montane forests sampled. This carbon store is endangered: we estimate that 0.8 million hectares of old-growth African montane forest have been lost since 2000. We provide country-specific montane forest AGC stock estimates modelled from our plot network to help to guide forest conservation and reforestation interventions. Our findings highlight the need for conserving these biodiverse(9,10) and carbon-rich ecosystems. The aboveground carbon stock of a montane African forest network is comparable to that of a lowland African forest network and two-thirds higher than default values for these montane forests.Peer reviewe