Big Storage, Little Budget

Daniel Andresen, Ph.D. is an associate professor of Computing & Information Sciences at Kansas State University and Director of the Institute for Computational Research. His research includes embedded and distributed computing, biomedical systems, and high performance scientific computing. Dr. Andresen coordinates the activities of the K-State research computing cluster, Beocat, and advises the local chapter of the Association for Computing Machinery (ACM). He is a National Science Foundation CAREER award winner, and has been granted research funding from the NSF, the Defense Advanced Research Projects Agency (DARPA), and industry. He is a member of the Association for Computing Machinery, the IEEE Computer Society, the Electronic Frontier Foundation, and the American Society for Engineering Education. ____________________________________________________________________________________________ Kyle Hutson has been involved with Linux system administration since 1994. He received his bachelor's degree from Kansas State University in computer engineering in 1995. He has worked in non-profit, public sector, and public sector IT services, including several years as a small business IT consultant. Kyle joined Kansas State University's HPC team in 2012. ____________________________________________________________________________________________ Adam Tygart has been an HPC system administrator since 2008. He has been using Linux since high school. Beocat, Kansas State University's Gentoo-based HPC cluster, was implemented in its current form by Adam while still an undergraduate. ____________________________________________________________________________________________ Presented at the 2015 Oklahoma Supercomputing Symposium at the University of Oklahoma Wednesday September 23 2015, 8:00am-5:00pm Thurman J. White Forum Building, 1704 Asp Ave., Norman OK 73072Kansas State University's HPC cluster was running out of storage space last year. Vendors of traditional HPC storage solutions were either too expensive to be feasible or too little capacity to be of long-term use. The system that ended up providing the best storage capacity for the available budget was Ceph, an open-source project that provides storage striped across many commodity servers. This session is a case study of the pros and cons of our implementation of a 1.5 PB Ceph-based storage cluster, discussing the history of network-based filesystems, including why our previous Gluster-based was no longer suitable. Questions and discussion are encouraged.University of Oklahoma / The University of Oklahoma Department of Information Technology / The University of Oklahoma Supercomputing Center for Education and Research / Kansas State UniversityN

Sex differences in fatigability following exercise normalised to the power-duration relationship

Due to morphological differences, females demonstrate greater fatigue resistance of locomotor muscle during single‐limb and whole‐body exercise modalities. Whilst females sustain a greater relative intensity of single‐limb, isometric exercise than males, limited investigation has been performed during whole‐body exercise. Accordingly, this study established the power‐duration relationship during cycling in 18 trained participants (8 females). Subsequently, constant‐load exercise was performed at critical power (CP)‐matched intensities within the heavy and severe domains, with the mechanisms of fatigability assessed via non‐invasive neurostimulation, near‐infrared spectroscopy, and pulmonary gas exchange during and following exercise. Relative CP (72±5 vs. 74±2% Pmax, p = 0.210) and curvature constant (51±11 vs. 52±10 J·Pmax−1, p = 0.733) of the power‐duration relationship were similar between males and females. Subsequent heavy (p = 0.758) and severe intensity (p = 0.645) exercise time to task failures were not different between sexes. However, females experienced lesser reductions in contractile function at task failure (p≤0.020), and greater vastus lateralis oxygenation (p≤0.039) during both trials. Reductions in voluntary activation occurred following both trials (p<0.001), but were less in females following the heavy trial (p = 0.036). Furthermore, during the heavy‐intensity trial only, corticospinal excitability was reduced at the cortical (p = 0.020) and spinal (p = 0.036) levels, but these reductions were not sex‐dependent. Other than a lower respiratory exchange ratio in the heavy trial for females (p = 0.039), no gas exchange variables differed between sexes (p≥0.052). Collectively, these data demonstrate that whilst the relative power‐duration relationship is not different between males and females, the mechanisms of fatigability during CP‐matched exercise above and below critical power are mediated by sex

The "Persuadable Middle" on Same-Sex Marriage: Formative Research to Build Support among Heterosexual College Students

Same-sex marriage is a controversial policy issue that affects the welfare of gay and lesbian couples throughout the USA. Considerable research examines opinions about same-sex marriage; however, studies have not investigated the covariates of the “persuadable middle”— those individuals who are neutral or unsure about their views. This group of people is often the target of same-sex marriage campaigns, yet they have received no empirical attention.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/89607/1/Woodford et al 2011 Persuadable Middle.pd

Xylella fastidiosa differentially accumulates mineral elements in biofilm and planktonic cells.

Xylella fastidiosa is a bacterial plant pathogen that infects numerous plant hosts. Disease develops when the bacterium colonizes the xylem vessels and forms a biofilm. Inductively coupled plasma optical emission spectroscopy was used to examine the mineral element content of this pathogen in biofilm and planktonic states. Significant accumulations of copper (30-fold), manganese (6-fold), zinc (5-fold), calcium (2-fold) and potassium (2-fold) in the biofilm compared to planktonic cells were observed. Other mineral elements such as sodium, magnesium and iron did not significantly differ between biofilm and planktonic cells. The distribution of mineral elements in the planktonic cells loosely mirrors the media composition; however the unique mineral element distribution in biofilm suggests specific mechanisms of accumulation from the media. A cell-to-surface attachment assay shows that addition of 50 to 100 µM Cu to standard X. fastidiosa media increases biofilm, while higher concentrations (>200 µM) slow cell growth and prevent biofilm formation. Moreover cell-to-surface attachment was blocked by specific chelation of copper. Growth of X. fastidiosa in microfluidic chambers under flow conditions showed that addition of 50 µM Cu to the media accelerated attachment and aggregation, while 400 µM prevented this process. Supplementation of standard media with Mn showed increased biofilm formation and cell-to-cell attachment. In contrast, while the biofilm accumulated Zn, supplementation to the media with this element caused inhibited growth of planktonic cells and impaired biofilm formation. Collectively these data suggest roles for these minerals in attachment and biofilm formation and therefore the virulence of this pathogen