bluuebunny/crossref_metadata_2025_split huggingface dataset:
Resource‐use strategies of native and invasive plants in Eastern North American forests
Authors: Heberling J. Mason , Fridley Jason D. 
Published: July 2013

Summary

Studies in disturbed, resource‐rich environments often show that invasive plants are more productive than co‐occurring natives, but with similar physiological tradeoffs. However, in resource‐limited habitats, it is unclear whether native and invasive plants have similar metabolic constraints or if invasive plants are more productive per unit resource cost – that is, use resources more efficiently.

Using a common garden to control for environment, we compared leaf physiological traits relating to resource investments, carbon returns, and resource‐use efficiencies in 14 native and 18 nonnative invasive species of common genera found in Eastern North American (ENA) deciduous forest understories, where growth is constrained by light and nutrient limitation.

Despite greater leaf construction and nitrogen costs, invaders exhibited greater instantaneous photosynthetic energy‐use efficiency (PEUE) and marginally greater photosynthetic nitrogen‐use efficiency (PNUE). When integrated over leaf lifespan (LL), these differences were magnified. Differences in efficiency were driven by greater productivity per unit leaf investment, as invaders exhibited both greater photosynthetic abilities and longer LL.

Our results indicate that woody understory invaders in ENA forests are not constrained to the same degree by leaf‐based metabolic tradeoffs as the native understory flora. These strategy differences could be attributable to pre‐adaptation in the native range, although other explanations are possible.
First record of Pentapharsodinium (Peridiniales, Dinophyceae) in the China Sea, with description of Pentapharsodinium dalei var. aciculiferum
Authors: Gu Haifeng , Luo Zhaohe , Zeng Ni , Lan Binbin , Lan Dongzhao 
Published: July 2013

SummaryThe dinophyte genus Pentapharsodinium shares an identical plate formula with that of Ensiculifera, but lacks a spine on the first cingulum plate and a median sulcal plate (Sm). Herein we established eight strains by incubating single cysts of Pentapharsodinium dalei from the Chukchi Sea, Yellow Sea, and South China Sea. The six strains from the Chukchi Sea and Yellow Sea fit the description of P. dalei, and they share identical internal transcribed spacer region (ITS1, ITS2 and 5.8S rDNA) sequences. The two other strains (G96 and PDFC01) from the South China Sea are morphologically similar to P. dalei, but they possess a spine on the anterior sulcal plate and an additional Sm plate. These two strains were described as P. dalei var. aciculiferum. They share identical ITS sequences and differ from P. dalei strains PDCH01 (Yellow Sea) and SZN19 (Norway origin) at 20 and 26 positions (96.40% and 95.32% similarity) respectively. Maximum‐likelihood and Bayesian inference resolved a well supported clade consisting of P. dalei and P. dalei var. aciculiferum. Our results reveal that cysts of P. dalei might comprise several morphologically, genetically, and ecologically different varieties.
Resveratrol inhibits fibrogenesis and induces apoptosis in keloid fibroblasts
Authors: Ikeda Kanae , Torigoe Toshihiko , Matsumoto Yoshitaka , Fujita Tatsuya , Sato Noriyuki , Yotsuyanagi Takatoshi 
Published: July 2013

AbstractKeloids are benign dermal fibrotic tumors arising during the wound healing process. The mechanisms of keloid formation and development still remain unknown, and no effective treatment is available. Resveratrol, a dietary compound, has anticancer properties and, from recent studies, it has been suggested that resveratrol may have an antifibrogenic effect on organs such as the liver and kidney. Based on this idea, we investigated its effect on the regulation of extracellular matrix expression, proliferation, and apoptosis of keloid fibroblasts. Type I collagen, α‐smooth muscle actin, and heat shock protein 47 expression decreased in resveratrol‐treated keloid fibroblasts in a dose‐dependent manner. In addition, resveratrol diminished transforming growth factor‐β1 production by keloid fibroblasts. We also demonstrated that it suppressed their proliferation and induced apoptosis of the fibroblasts. Conversely, resveratrol did not decrease type I collagen, α‐smooth muscle actin, and heat shock protein 47 mRNA expression in normal skin fibroblasts and barely suppressed cell proliferation. Our data indicate that resveratrol may have an antifibrogenic effect on keloid fibroblasts without any adversely effects on normal skin fibroblasts, suggesting the potential application of resveratrol for the treatment of keloids.
Generic pseudogroups on and the topology of leaves
Authors: Mattei J.-F. , Rebelo J. C. , Reis H. 
Published: July 2013

AbstractWe show that generically a pseudogroup generated by holomorphic diffeomorphisms defined about $0\in \mathbb{C} $ is free in the sense of pseudogroups even if the class of conjugacy of the generators is fixed. This result has a number of consequences on the topology of leaves for a (singular) holomorphic foliation defined on a neighborhood of an invariant curve. In particular, in the classical and simplest case arising from local nilpotent foliations possessing a unique separatrix which is given by a cusp of the form $\{ {y}^{2} - {x}^{2n+ 1} = 0\} $, our results allow us to settle the problem of showing that a generic foliation possesses only countably many non-simply connected leaves.
Precision predictions for electroweak superpartner production at hadron colliders with Resummino
Authors: Fuks Benjamin , Klasen Michael , Lamprea David R. , Rothering Marcel 
Published: July 2013

AbstractWe describe the Resummino package, a C++ and Fortran program dedicated to precision calculations in the framework of gaugino and slepton pair production at hadron colliders. This code allows to calculate transverse-momentum and invariant-mass distributions as well as total cross sections by combining the next-to-leading order predictions obtained by means of perturbative QCD with the resummation of the large logarithmic contributions arising in the small transverse-momentum region and close to the production threshold. The results computed in this way benefit from reduced theoretical uncertainties, compared to a pure next-to-leading order approach as currently employed in the experimental analyses searching for sleptons and gauginos at hadron colliders. This is illustrated by using Resummino in the context of a typical supersymmetric benchmark point dedicated to superpartner searches at the Large Hadron Collider.
Parasol and GreenSwitch
Authors: Goiri Íñigo , Katsak William , Le Kien , Nguyen Thu D. , Bianchini Ricardo 
Published: July 2013

Several companies have recently announced plans to build "green" datacenters, i.e. datacenters partially or completely powered by renewable energy. These datacenters will either generate their own renewable energy or draw it directly from an existing nearby plant. Besides reducing carbon footprints, renewable energy can potentially reduce energy costs, reduce peak power costs, or both. However, certain renewable fuels are intermittent, which requires approaches for tackling the energy supply variability. One approach is to use batteries and/or the electrical grid as a backup for the renewable energy. It may also be possible to adapt the workload to match the renewable energy supply. For highest benefits, green datacenter operators must intelligently manage their workloads and the sources of energy at their disposal.
In this paper, we first discuss the tradeoffs involved in building green datacenters today and in the future. Second, we present Parasol, a prototype green datacenter that we have built as a research platform. Parasol comprises a small container, a set of solar panels, a battery bank, and a grid-tie. Third, we describe GreenSwitch, our model-based approach for dynamically scheduling the workload and selecting the source of energy to use. Our real experiments with Parasol, GreenSwitch, and MapReduce workloads demonstrate that intelligent workload and energy source management can produce significant cost reductions. Our results also isolate the cost implications of peak power management, storing energy on the grid, and the ability to delay the MapReduce jobs. Finally, our results demonstrate that careful workload and energy source management can minimize the negative impact of electrical grid outages.
The rise of the expert amateur
Authors: Paulos Eric 
Published: July 2013

We are at an important technological inflection point. Most of our computing systems have been designed and built by professionally trained experts (i.e. us -- computer scientists, engineers, and designers) for use in specific domains and to solve explicit prob-lems. Artifacts often called "user manuals" traditionally prescribed the appropriate usage of these tools and implied an acceptable etiquette for interaction and experience. A fringe group of individuals usually labeled "hackers" or "amateurs" or "makers" have challenged this producer-consumer model of technology by creating novel hardware and software features to "improve" our research and products while a similar creative group of technicians called "artists" have redirected the techniques, tools, and tenets of accepted technological usage away from their typical manifestations in practicality and product. Over time the technological artifacts of these fringe groups and the support for their rhetoric have gained them a foothold into computing culture and eroded the established power discontinuities within the practice of computing research. We now expect our computing tools to be driven by an architecture of open participation and democracy that encourages users to add value to their tools and applications as they use them. Similarly, the bar for enabling the design of novel, personal computing systems and "hardware remixes" has fallen to the point where many non-experts and novices are readily embracing and creating fascinating and ingenious computing artifacts outside of our official and traditionally sanctioned academic and industrial research communities.
But how have we as "expert" practitioners been influencing this discussion? By constructing a practice around the design and development of technology for task based and problem solving applications, we have unintentionally established such work as the status quo for the human computing experience. We have failed in our duty to open up alternate forums for technology to express itself and touch our lives beyond productivity and efficiency. Blinded by our quest for "smart technologies" we have forgotten to contemplate the design of technologies to inspire us to be smarter, more curious, and more inquisitive. We owe it to ourselves to rethink the impact we desire to have on this historic moment in computing culture. We must choose to participate in and perhaps lead a dialogue that heralds an expansive new acceptable practice of designing to enable participation by experts and non-experts alike. We are in the milieu of the rise of the "expert amateur". We must change our mantra -- not just performance, completeness, and usability but openness, usefulness and relevancy to our world, its citizens, and our environment. This talk will explore elements of the DIY and maker culture and its relevancy to research questions across computational hardware, languages, and systems. Ultimately, this talk will outline and argue for expanding the design territory and potential opportunities for all of us to collaborate and benefit as a society from this cultural movement.
DeAliaser
Authors: Ahn Wonsun , Duan Yuelu , Torrellas Josep 
Published: July 2013

Alias analysis is a critical component in many compiler optimizations. A promising approach to reduce the complexity of alias analysis is to use speculation. The approach consists of performing optimizations assuming the alias relationships that are true most of the time, and repairing the code when such relationships are found not to hold through runtime checks.
This paper proposes a general alias speculation scheme that leverages upcoming hardware support for transactions with the help of some ISA extensions. The ability of transactions to checkpoint and roll back frees the compiler to pursue aggressive optimizations without having to worry about recovery code. Also, exposing the memory conflict detection hardware in transactions to software allows runtime checking of aliases with little or no overhead. We test the potential of the novel alias speculation approach with Loop Invariant Code Motion (LICM), Global Value Numbering (GVN), and Partial Redundancy Elimination (PRE) optimization passes. On average, they are shown to reduce program execution time by 9% in SPEC FP2006 applications and 3% in SPEC INT2006 applications over the alias analysis of a state-of-the-art compiler.
Why you should care about quantile regression
Authors: de Oliveira Augusto Born , Fischmeister Sebastian , Diwan Amer , Hauswirth Matthias , Sweeney Peter F. 
Published: July 2013

Research has shown that correctly conducting and analysing computer performance experiments is difficult. This paper investigates what is necessary to conduct successful computer performance evaluation by attempting to repeat a prior experiment: the comparison between two Linux schedulers.
In our efforts, we found that exploring an experimental space through a series of incremental experiments can be inconclusive, and there may be no indication of how much experimentation will be enough. Analysis of variance (ANOVA), a traditional analysis method, is able to partly solve the problems with the previous approach, but we demonstrate that ANOVA can be insufficient for proper analysis due to the requirements it imposes on the data.
Finally, we demonstrate the successful application of quantile regression, a recent development in statistics, to computer performance experiments. Quantile regression can provide more insight into the experiment than ANOVA, with the additional benefit of being applicable to data from any distribution. This property makes it especially useful in our field, since non-normally distributed data is common in computer experiments.
STABILIZER
Authors: Curtsinger Charlie , Berger Emery D. 
Published: July 2013

Researchers and software developers require effective performance evaluation. Researchers must evaluate optimizations or measure overhead. Software developers use automatic performance regression tests to discover when changes improve or degrade performance. The standard methodology is to compare execution times before and after applying changes.
Unfortunately, modern architectural features make this approach unsound. Statistically sound evaluation requires multiple samples to test whether one can or cannot (with high confidence) reject the null hypothesis that results are the same before and after. However, caches and branch predictors make performance dependent on machine-specific parameters and the exact layout of code, stack frames, and heap objects. A single binary constitutes just one sample from the space of program layouts, regardless of the number of runs. Since compiler optimizations and code changes also alter layout, it is currently impossible to distinguish the impact of an optimization from that of its layout effects.
This paper presents Stabilizer, a system that enables the use of the powerful statistical techniques required for sound performance evaluation on modern architectures. Stabilizer forces executions to sample the space of memory configurations by repeatedly re-randomizing layouts of code, stack, and heap objects at runtime. Stabilizer thus makes it possible to control for layout effects. Re-randomization also ensures that layout effects follow a Gaussian distribution, enabling the use of statistical tests like ANOVA. We demonstrate Stabilizer's efficiency (<7% median overhead) and its effectiveness by evaluating the impact of LLVM's optimizations on the SPEC CPU2006 benchmark suite. We find that, while -O2 has a significant impact relative to -O1, the performance impact of -O3 over -O2 optimizations is indistinguishable from random noise.
Demand-based coordinated scheduling for SMP VMs
Authors: Kim Hwanju , Kim Sangwook , Jeong Jinkyu , Lee Joonwon , Maeng Seungryoul 
Published: July 2013

As processor architectures have been enhancing their computing capacity by increasing core counts, independent workloads can be consolidated on a single node for the sake of high resource efficiency in data centers. With the prevalence of virtualization technology, each individual workload can be hosted on a virtual machine for strong isolation between co-located workloads. Along with this trend, hosted applications have increasingly been multithreaded to take advantage of improved hardware parallelism. Although the performance of many multithreaded applications highly depends on communication (or synchronization) latency, existing schemes of virtual machine scheduling do not explicitly coordinate virtual CPUs based on their communication behaviors.
This paper presents a demand-based coordinated scheduling scheme for consolidated virtual machines that host multithreaded workloads. To this end, we propose communication-driven scheduling that controls time-sharing in response to inter-processor interrupts (IPIs) between virtual CPUs. On the basis of in-depth analysis on the relationship between IPI communications and coordination demands, we devise IPI-driven coscheduling and delayed preemption schemes, which effectively reduce synchronization latency and unnecessary CPU consumption. In addition, we introduce a load-conscious CPU allocation policy in order to address load imbalance in heterogeneously consolidated environments. The proposed schemes are evaluated with respect to various scenarios of mixed workloads using the PARSEC multithreaded applications. In the evaluation, our scheme improves the overall performance of consolidated workloads, especially communication-intensive applications, by reducing inefficient synchronization latency.
Efficient virtualization on embedded power architecture® platforms
Authors: Mittal Aashish , Bansal Dushyant , Bansal Sorav , Sethi Varun 
Published: July 2013

Power Architecture® processors are popular and widespread on embedded systems, and such platforms are increasingly being used to run virtual machines. While the Power Architecture meets the Popek-and-Goldberg virtualization requirements for traditional trap-and-emulate style virtualization, the performance overhead of virtualization remains high. For example, workloads exhibiting a large amount of kernel activity typically show 3-5x slowdowns over bare-metal.
Recent additions to the Linux kernel contain guest and host side paravirtual extensions for Power Architecture platforms. While these extensions improve performance significantly, they are guest-specific, guest-intrusive, and cover only a subset of all possible virtualization optimizations.
We present a set of host-side optimizations that achieve comparable performance to the aforementioned paravirtual extensions, on an unmodified guest. Our optimizations are based on adaptive in-place binary translation. Unlike the paravirtual approach, our solution is guest neutral. We implement our ideas in a prototype based on Qemu/KVM. After our modifications, KVM can boot an unmodified Linux guest around 2.5x faster. We contrast our optimization approach with previous similar binary translation based approaches for the x86 architecture; in our experience, each architecture presents a unique set of challenges and optimization opportunities.
LUCAS
Authors: Porpodas Vasileios , Cintra Marcelo 
Published: July 2013

Clustered VLIW architectures are statically scheduled wide-issue architectures that combine the advantages of wide-issue processors along with the power and frequency scalability of clustered designs. Being statically scheduled, they require that the decision of mapping instructions to clusters be done by the compiler. State-of-the-art code generation for such architectures combines cluster-assignment and instruction scheduling in a single unified pass. The performance of the generated code, however, is very susceptible to the inter-cluster communication latency. This is due to the nature of the two clustering heuristics used. One is aggressive and works well for low inter-cluster latencies, while the other is more conservative and works well only for high latencies.
In this paper we propose LUCAS, a novel unified cluster-assignment and instruction-scheduling algorithm that adapts to the inter-cluster latency better than the existing state-of-the-art schemes. LUCAS is a hybrid scheme that performs fine-grain switching between the two state-of-the art clustering heuristics, leading to better scheduling than either of them. It generates better performing code for a wide range of inter-cluster latency values.
Combined WCET analysis of bitcode and machine code using control-flow relation graphs
Authors: Huber Benedikt , Prokesch Daniel , Puschner Peter 
Published: July 2013

Static program analyses like stack usage analysis and worst-case execution time (WCET) analysis depend on the actual machine code generated by the compiler for the target system. As the analysis of binary code is costly, hard to diagnose and platform dependent, it is preferable to carry out parts of these analyses on a higher-level program representation. To this end, the higher-level code and the machine code need to be related, a difficult task due to the complexity of modern optimizing compilers.
In this article, we present a novel representation called control-flow relation graphs, which provide an accurate model of the control-flow relation between machine code and the compiler's intermediate representation. In order to facilitate the integration of our approach in existing compiler frameworks, we develop a construction algorithm that builds the control-flow relation graph from partial mappings provided by the compiler. The WCET calculation method for control-flow relation graphs processes flow information from both the intermediate representation and machine code. Furthermore, we demonstrate the transformation of flow information from the IR to the machine code level, in order to use existing industrial-strength WCET analysis tools operating on machine code. We implemented the construction algorithm within the LLVM compiler framework, along with an implementation of the combined WCET calculation method.
The evaluation demonstrates that the approach is able to relate bitcode (LLVM's intermediate representation) and machine code in a precise way, with a WCET increase of at most 2% when using flow facts on the bitcode level, compared to equivalent ones on the machine-code level. As the methods presented in this article provide a cost-effective way to reuse platform independent flow information, they have the potential to simplify WCET analysis, and popularize its use in the development process of real-time systems.