bluuebunny/crossref_metadata_2025 huggingface dataset:
Business Growth in Established Companies; Roles of Effectuation and Causation
Authors: Matalamäki Marko , Vuorinen Tero , Varamäki Elina , Sorama Kirsti
Published: September 2017

This multiple case study illustrates how ten selected industrial companies have managed to accomplish rapid growth after a long period (3–5 years) of slow growth. A particular aim was to determine whether these companies grew by adapting to the situation and responding to the demands of the market with their resources (effectuation) or by following previously determined plans and proceeding towards set goals (causation). Effectuation was originally connected to the creation of new business activities and an operating model covering the early stages of an organisation’s growth. However, recent studies have considered effectuation in the context of an existing business. This paper adds business growth to the context of established companies and explores the roles of effectuation and causation in their growth processes. The findings indicate the usage of both logics, but in nine of the ten companies’ effectuation influences as the dominant approach. Only one of the ten studied companies can be stated to follow the operating principles of causation.
Automorphisms for Some Symmetric Multiparameter Quantized Weyl Algebras and Their Localizations
Authors: Tang Xin
Published: September 2017

We study a family of “symmetric” multiparameter quantized Weyl algebras [Formula: see text] and some related algebras. We compute the Nakayama automorphism of [Formula: see text], give a necessary and sufficient condition for [Formula: see text] to be Calabi-Yau, and prove that [Formula: see text] is cancellative. We study the automorphisms and isomorphism problem for [Formula: see text] and [Formula: see text]. Similar results are established for the Maltsiniotis multiparameter quantized Weyl algebra [Formula: see text] and its polynomial extension. We prove a quantum analogue of the Dixmier conjecture for a simple localization [Formula: see text] and determine its automorphism group.
The Projective Cover of the Trivial Representation for a Finite Group of Lie Type in Defining Characteristic
Authors: Koshitani Shigeo , Müller Jürgen
Published: September 2017

We give a lower bound of the Loewy length of the projective cover of the trivial module for the group algebra kG of a finite group G of Lie type defined over a finite field of odd characteristic p, where k is an arbitrary field of characteristic p. The proof uses Auslander-Reiten theory.
Heptavalent Symmetric Graphs of Order 16p
Authors: Guo Songtao , Hou Hailong , Xu Yong
Published: September 2017

A graph is symmetric if its automorphism group acts transitively on the set of arcs of the graph. We classify connected heptavalent symmetric graphs of order 16p for each prime p. As a result, there are two such sporadic graphs with p = 3 and 7, and an infinite family of 1-regular normal Cayley graphs on the group [Formula: see text] with 7|(p – 1).
COMPARISON OF ONSITE INFILTRATION AND CONSTANT RATE INFUSION FOR POSTOPERATIVE ANALGESIA IN DOGS WITH MAMMARY TUMORS UNDERGOING BILATERAL RADICAL MASTECTOMY AND OVARIOHYSTERECTOMY
Authors: Wang Hui-Ju , Chang Shih-Chieh , Lee Wei-Ming , Chen Kuan-Sheng , Wang Hsien-Chi
Published: September 2017

Analgesia of the wide surgical excision region in surgeries such as bilateral radical mastectomy plays an important role in postoperative care. Opioids are effective in alleviating pain; however, they are sometimes difficult to obtain in most local veterinary hospitals. The objective of this research was to compare the efficacies of (1) onsite infiltration analgesia with lidocaine and bupivacaine (group I, [Formula: see text]) and intravenous injection with buprenorphine and (2) constant rate infusions (CRIs) of fentanyl and ketamine (group II, [Formula: see text]) for postoperative analgesia after bilateral radical mastectomy and ovariohysterectomy in dogs with mammary tumors. The results showed that a combination of infiltration with lidocaine and bupivacaine and intravenous injection with buprenorphine was as effective as CRIs of fentanyl and ketamine. Infiltration analgesia with lidocaine and bupivacaine may be an option for analgesia in dogs undergoing bilateral mastectomy and ovariohysterectomy and may help reducing pure [Formula: see text]-opioid requirements.
The Complexity of Mean-Payoff Pushdown Games
Authors: Chatterjee Krishnendu , Velner Yaron
Published: September 2017

Two-player games on graphs are central in many problems in formal verification and program analysis, such as synthesis and verification of open systems. In this work, we consider solving recursive game graphs (or pushdown game graphs) that model the control flow of sequential programs with recursion. While pushdown games have been studied before with qualitative objectives—such as reachability and ω-regular objectives—in this work, we study for the first time such games with the most well-studied quantitative objective, the mean-payoff objective. In pushdown games, two types of strategies are relevant: (1) global strategies, which depend on the entire global history; and (2) modular strategies, which have only local memory and thus do not depend on the context of invocation but rather only on the history of the current invocation of the module. Our main results are as follows: (1) One-player pushdown games with mean-payoff objectives under global strategies are decidable in polynomial time. (2) Two-player pushdown games with mean-payoff objectives under global strategies are undecidable. (3) One-player pushdown games with mean-payoff objectives under modular strategies are NP-hard. (4) Two-player pushdown games with mean-payoff objectives under modular strategies can be solved in NP (i.e., both one-player and two-player pushdown games with mean-payoff objectives under modular strategies are NP-complete). We also establish the optimal strategy complexity by showing that global strategies for mean-payoff objectives require infinite memory even in one-player pushdown games and memoryless modular strategies are sufficient in two-player pushdown games. Finally, we also show that all the problems have the same complexity if the stack boundedness condition is added, where along with the mean-payoff objective the player must also ensure that the stack height is bounded.
Do Humans Play Equilibrium? Modeling Human Behavior in Computational Strategic Systems
Authors: Noti Gali
Published: September 2017

Online auctions and other computational strategic systems where human users interact are usually analyzed based on the assumptions that the users are rational and reach an equilibrium. This article shows that these modeling assumptions lead to significant errors, and that using behaviorally appropriate assumptions is important for achieving credible predictions in such systems.
Dynamic translation of structured Loads/Stores and register mapping for architectures with SIMD extensions
Authors: Fu Sheng-Yu , Hong Ding-Yong , Liu Yu-Ping , Wu Jan-Jan , Hsu Wei-Chung
Published: September 2017

More and more modern processors have been supporting non-contiguous SIMD data accesses. However, translating such instructions has been overlooked in the Dynamic Binary Translation (DBT) area. For example, in the popular QEMU dynamic binary translator, guest memory instructions with strides are emulated by a sequence of scalar instructions, leaving a significant room for performance improvement when the host machines have SIMD instructions available. Structured loads/stores, such as VLDn/VSTn in ARM NEON, are one type of strided SIMD data access instructions. They are widely used in signal processing, multimedia, mathematical and 2D matrix transposition applications. Efficient translation of such structured loads/stores is a critical issue when migrating ARM executables to other ISAs. However, it is quite challenging since not only the translation of structured loads/stores is not trivial, but also the difference between guest and host register configurations must be taken into consideration. In this work, we present the design and implementation of translating structured loads/stores in DBT, including target code generation as well as efficient SIMD register mapping. Our proposed register mapping mechanisms are not limited to handling structured loads/stores, they can be extended to deal with normal SIMD instructions. On a set of OpenCV benchmarks, our QEMU-based system has achieved a maximum speedup of 5.41x, with an average improvement of 2.93x. On a set of BLAS benchmarks, our system has also obtained a maximum speedup of 2.19x and an average improvement of 1.63x.
Proactive and adaptive energy-aware programming with mixed typechecking
Authors: Canino Anthony , Liu Yu David
Published: September 2017

Application-level energy management is an important dimension of energy optimization. In this paper, we introduce ENT, a novel programming language for enabling *proactive* and *adaptive* mode-based energy management at the application level. The proactive design allows programmers to apply their application knowledge to energy management, by characterizing the energy behavior of different program fragments with modes. The adaptive design allows such characterization to be delayed until run time, useful for capturing dynamic program behavior dependent on program states, configuration settings, external battery levels, or CPU temperatures. The key insight is both proactiveness and adaptiveness can be unified under a type system combined with static typing and dynamic typing. ENT has been implemented as an extension to Java, and successfully ported to three energy-conscious platforms: an Intel-based laptop, a Raspberry Pi, and an Android phone. Evaluation shows ENT improves the programmability, debuggability, and energy efficiency of battery-aware and temperature-aware programs.
Bringing the web up to speed with WebAssembly
Authors: Haas Andreas , Rossberg Andreas , Schuff Derek L. , Titzer Ben L. , Holman Michael , Gohman Dan , Wagner Luke , Zakai Alon , Bastien JF
Published: September 2017

The maturation of the Web platform has given rise to sophisticated and demanding Web applications such as interactive 3D visualization, audio and video software, and games. With that, efficiency and security of code on the Web has become more important than ever. Yet JavaScript as the only built-in language of the Web is not well-equipped to meet these requirements, especially as a compilation target.

Engineers from the four major browser vendors have risen to the challenge and collaboratively designed a portable low-level bytecode called WebAssembly. It offers compact representation, efficient validation and compilation, and safe low to no-overhead execution. Rather than committing to a specific programming model, WebAssembly is an abstraction over modern hardware, making it language-, hardware-, and platform-independent, with use cases beyond just the Web. WebAssembly has been designed with a formal semantics from the start. We describe the motivation, design and formal semantics of WebAssembly and provide some preliminary experience with implementations.
Systematic black-box analysis of collaborative web applications
Authors: Billes Marina , Møller Anders , Pradel Michael
Published: September 2017

Web applications, such as collaborative editors that allow multiple clients to concurrently interact on a shared resource, are difficult to implement correctly. Existing techniques for analyzing concurrent software do not scale to such complex systems or do not consider multiple interacting clients. This paper presents Simian, the first fully automated technique for systematically analyzing multi-client web applications.

Naively exploring all possible interactions between a set of clients of such applications is practically infeasible. Simian obtains scalability for real-world applications by using a two-phase black-box approach. The application code remains unknown to the analysis and is first explored systematically using a single client to infer potential conflicts between client events triggered in a specific context. The second phase synthesizes multi-client interactions targeted at triggering misbehavior that may result from the potential conflicts, and reports an inconsistency if the clients do not converge to a consistent state.

We evaluate the analysis on three widely used systems, Google Docs, Firepad, and ownCloud Documents, where it reports a variety of inconsistencies, such as incorrect formatting and misplaced text fragments. Moreover, we find that the two-phase approach runs 10x faster compared to exhaustive exploration, making systematic analysis practically applicable.
MigVisor
Authors: Zhang Jinshi , Dong Eddie , Li Jian , Guan Haibing
Published: September 2017

Live migration of a virtual machine (VM) is a powerful technique with benefits of server maintenance, resource management, dynamic workload re-balance, etc. Modern research has effectively reduced the VM live migration (VMLM) time to dozens of milliseconds, but live migration still exhibits failures if it cannot terminate within the given time constraint. The ability to predict this type of failure can avoid wasting networking and computing resources on the VM migration, and the associated system performance degradation caused by wasting these resources. The cost of VM live migration highly depends on the application workload of the VM, which may undergo frequent changes. At the same time, the available system resources for VM migration can also change substantially and frequently. To account for these issues, we present a solution called MigVisor, which can accurately predict the behaviour of VM migration using working-set model. This can enable system managers to predict the migration cost and enhance the system management efficacy. The experimental results prove the design suitability and show that the MigVisor has a high prediction accuracy since the average relative error between the predicted value and the measured value is only 6.2%~9%.
Just-In-Time GPU Compilation for Interpreted Languages with Partial Evaluation
Authors: Fumero Juan , Steuwer Michel , Stadler Lukas , Dubach Christophe
Published: September 2017

Computer systems are increasingly featuring powerful parallel devices with the advent of many-core CPUs and GPUs. This offers the opportunity to solve computationally-intensive problems at a fraction of the time traditional CPUs need. However, exploiting heterogeneous hardware requires the use of low-level programming language approaches such as OpenCL, which is incredibly challenging, even for advanced programmers.

On the application side, interpreted dynamic languages are increasingly becoming popular in many domains due to their simplicity, expressiveness and flexibility. However, this creates a wide gap between the high-level abstractions offered to programmers and the low-level hardware-specific interface. Currently, programmers must rely on high performance libraries or they are forced to write parts of their application in a low-level language like OpenCL. Ideally, nonexpert programmers should be able to exploit heterogeneous hardware directly from their interpreted dynamic languages.

In this paper, we present a technique to transparently and automatically offload computations from interpreted dynamic languages to heterogeneous devices. Using just-in-time compilation, we automatically generate OpenCL code at runtime which is specialized to the actual observed data types using profiling information. We demonstrate our technique using R, which is a popular interpreted dynamic language predominately used in big data analytic. Our experimental results show the execution on a GPU yields speedups of over 150x compared to the sequential FastR implementation and the obtained performance is competitive with manually written GPU code. We also show that when taking into account start-up time, large speedups are achievable, even when the applications run for as little as a few seconds.
Decoupled Affine Computation for SIMT GPUs
Authors: Wang Kai , Lin Calvin
Published: September 2017

This paper introduces a method of decoupling affine computations---a class of expressions that produces extremely regular values across SIMT threads---from the main execution stream, so that the affine computations can be performed with greater efficiency and with greater independence from the main execution stream. This decoupling has two benefits: (1) For compute-bound programs, it significantly reduces the dynamic warp instruction count; (2) for memory-bound workloads, it significantly reduces memory latency, since it acts as a non-speculative prefetcher for the data specified by the many memory address calculations that are affine computations.

We evaluate our solution, known as Decoupled Affine Computation (DAC), using GPGPU-sim and a set of 29 GPGPU programs. We find that on average, DAC improves performance by 40% and reduces energy consumption by 20%. For the 11 compute-bound benchmarks, DAC improves performance by 34%, compared with 11% for the previous state-of-the-art. For the 18 memory-bound programs, DAC improves performance by an average of 44%, compared with 16% for state-of-the-art GPU prefetcher.
Chasing Away RAts
Authors: Sinclair Matthew D. , Alsop Johnathan , Adve Sarita V.
Published: September 2017

An unambiguous and easy-to-understand memory consistency model is crucial for ensuring correct synchronization and guiding future design of heterogeneous systems. In a widely adopted approach, the memory model guarantees sequential consistency (SC) as long as programmers obey certain rules. The popular data-race-free-0 (DRF0) model exemplifies this SC-centric approach by requiring programmers to avoid data races. Recent industry models, however, have extended such SC-centric models to incorporate relaxed atomics. These extensions can improve performance, but are difficult to specify formally and use correctly. This work addresses the impact of relaxed atomics on consistency models for heterogeneous systems in two ways. First, we introduce a new model, Data-Race-Free-Relaxed (DRFrlx), that extends DRF0 to provide SC-centric semantics for the common use cases of relaxed atomics. Second, we evaluate the performance of relaxed atomics in CPU-GPU systems for these use cases. We find mixed results -- for most cases, relaxed atomics provide only a small benefit in execution time, but for some cases, they help significantly (e.g., up to 51% for DRFrlx over DRF0).
EDDIE
Authors: Nazari Alireza , Sehatbakhsh Nader , Alam Monjur , Zajic Alenka , Prvulovic Milos
Published: September 2017

This paper describes EM-Based Detection of Deviations in Program Execution (EDDIE), a new method for detecting anomalies in program execution, such as malware and other code injections, without introducing any overheads, adding any hardware support, changing any software, or using any resources on the monitored system itself. Monitoring with EDDIE involves receiving electromagnetic (EM) emanations that are emitted as a side effect of execution on the monitored system, and it relies on spikes in the EM spectrum that are produced as a result of periodic (e.g. loop) activity in the monitored execution. During training, EDDIE characterizes normal execution behavior in terms of peaks in the EM spectrum that are observed at various points in the program execution, but it does not need any characterization of the malware or other code that might later be injected. During monitoring, EDDIE identifies peaks in the observed EM spectrum, and compares these peaks to those learned during training. Since EDDIE requires no resources on the monitored machine and no changes to the monitored software, it is especially well suited for security monitoring of embedded and IoT devices. We evaluate EDDIE on a real IoT system and in a cycle-accurate simulator, and find that even relatively brief injected bursts of activity (a few milliseconds) are detected by EDDIE with high accuracy, and that it also accurately detects when even a few instructions are injected into an existing loop within the application.
MTraceCheck
Authors: Lee Doowon , Bertacco Valeria
Published: September 2017

This work presents a minimally-intrusive, high-performance, post-silicon validation framework for validating memory consistency in multi-core systems. Our framework generates constrained-random tests that are instrumented with observability-enhancing code for memory consistency verification. For each test, we generate a set of compact signatures reflecting the memory-ordering patterns observed over many executions of the test, with each of the signatures corresponding to a unique memory-ordering pattern. We then leverage an efficient and novel analysis to quickly determine if the observed execution patterns represented by each unique signature abide by the memory consistency model. Our analysis derives its efficiency by exploiting the structural similarities among the patterns observed.

We evaluated our framework, MTraceCheck, on two platforms: an x86-based desktop and an ARM-based SoC platform, both running multi-threaded test programs in a bare-metal environment. We show that MTraceCheck reduces the perturbation introduced by the memory-ordering monitoring activity by 93% on average, compared to a baseline register flushing approach that saves the register's state after each load operation. We also reduce the computation requirements of our consistency checking analysis by 81% on average, compared to a conventional topological sorting solution. We finally demonstrate the effectiveness of MTraceCheck on buggy designs, by evaluating multiple case studies where it successfully exposes subtle bugs in a full-system simulation environment.
Hiding the Long Latency of Persist Barriers Using Speculative Execution
Authors: Shin Seunghee , Tuck James , Solihin Yan
Published: September 2017

Byte-addressable non-volatile memory technology is emerging as an alternative for DRAM for main memory. This new Non-Volatile Main Memory (NVMM) allows programmers to store important data in data structures in memory instead of serializing it to the file system, thereby providing a substantial performance boost. However, modern systems reorder memory operations and utilize volatile caches for better performance, making it difficult to ensure a consistent state in NVMM. Intel recently announced a new set of persistence instructions, clflushopt, clwb, and pcommit. These new instructions make it possible to implement fail-safe code on NVMM, but few workloads have been written or characterized using these new instructions.

In this work, we describe how these instructions work and how they can be used to implement write-ahead logging based transactions. We implement several common data structures and kernels and evaluate the performance overhead incurred over traditional non-persistent implementations. In particular, we find that persistence instructions occur in clusters along with expensive fence operations, they have long latency, and they add a significant execution time overhead, on average by 20.3% over code with logging but without fence instructions to order persists.

To deal with this overhead and alleviate the performance bottleneck, we propose to speculate past long latency persistency operations using checkpoint-based processing. Our speculative persistence architecture reduces the execution time overheads to only 3.6%.
HeteroOS
Authors: Kannan Sudarsun , Gavrilovska Ada , Gupta Vishal , Schwan Karsten
Published: September 2017

Heterogeneous memory management combined with server virtualization in datacenters is expected to increase the software and OS management complexity. State-of-the-art solutions rely exclusively on the hypervisor (VMM) for expensive page hotness tracking and migrations, limiting the benefits from heterogeneity. To address this, we design HeteroOS, a novel application-transparent OS-level solution for managing memory heterogeneity in virtualized system. The HeteroOS design first makes the guest-OSes heterogeneity-aware and then extracts rich OS-level information about applications' memory usage to place data in the 'right' memory avoiding page migrations. When such pro-active placements are not possible, HeteroOS combines the power of the guest-OSes' information about applications with the VMM's hardware control to track for hotness and migrate only performance-critical pages. Finally, HeteroOS also designs an efficient heterogeneous memory sharing across multiple guest-VMs. Evaluation of HeteroOS with memory, storage, and network-intensive datacenter applications shows up to 2x performance improvement compared to the state-of-the-art VMM-exclusive approach.
Footprint
Authors: Fu Binzhang , Kim John
Published: September 2017

Routing algorithms can improve network performance by maximizing routing adaptiveness but can be problematic in the presence of endpoint congestion. Tree-saturation is a well-known behavior caused by endpoint congestion. Adaptive routing can, however, spread the congestion and result in thick branches of the congestion tree -- creating Head-of-Line (HoL) blocking and degrading performance. In this work, we identify how ignoring virtual channels (VCs) and their occupancy during adaptive routing results in congestion trees with thick branches as congestion is spread to all VCs. To address this limitation, we propose Footprint routing algorithm -- a new adaptive routing algorithm that minimizes the size of the congestion tree, both in terms of the number of nodes in the congestion tree as well as branch thickness. Footprint achieves this by regulating adaptiveness by requiring packets to follow the path of prior packets to the same destination if the network is congested instead of forking a new path or VC. Thus, the congestion tree is dynamically kept as slim as possible and reduces HoL blocking or congestion spreading while maintaining high adaptivity and maximizing VC buffer utilization. We evaluate the proposed Footprint routing algorithm against other adaptive routing algorithms and our simulation results show that the network saturation throughput can be improved by up to 43% (58%) compared with the fully adaptive routing (partially adaptive routing) algorithms.
EbDa
Authors: Ebrahimi Masoumeh , Daneshtalab Masoud
Published: September 2017

Freedom from deadlock is one of the most important issues when designing routing algorithms in on-chip/off-chip networks. Many works have been developed upon Dally's theory proving that a network is deadlock-free if there is no cyclic dependency on the channel dependency graph. However, finding such acyclic graph has been very challenging, which limits Dally's theory to networks with a low number of channels. In this paper, we introduce three theorems that directly lead to routing algorithms with an acyclic channel dependency graph. We also propose the partitioning methodology, enabling a design to reach the maximum adaptiveness for the n-dimensional mesh and k-ary n-cube topologies with any given number of channels. In addition, deadlock-free routing algorithms can be derived ranging from maximally fully adaptive routing down to deterministic routing. The proposed theorems can drastically remove the difficulties of designing deadlock-free routing algorithms.
Stream-Dataflow Acceleration
Authors: Nowatzki Tony , Gangadhar Vinay , Ardalani Newsha , Sankaralingam Karthikeyan
Published: September 2017

Demand for low-power data processing hardware continues to rise inexorably. Existing programmable and "general purpose" solutions (eg. SIMD, GPGPUs) are insufficient, as evidenced by the order-of-magnitude improvements and industry adoption of application and domain-specific accelerators in important areas like machine learning, computer vision and big data. The stark tradeoffs between efficiency and generality at these two extremes poses a difficult question: how could domain-specific hardware efficiency be achieved without domain-specific hardware solutions?

In this work, we rely on the insight that "acceleratable" algorithms have broad common properties: high computational intensity with long phases, simple control patterns and dependences, and simple streaming memory access and reuse patterns. We define a general architecture (a hardware-software interface) which can more efficiently expresses program with these properties called stream-dataflow. The dataflow component of this architecture enables high concurrency, and the stream component enables communication and coordination at very-low power and area overhead. This paper explores the hardware and software implications, describes its detailed microarchitecture, and evaluates an implementation. Compared to a state-of-the-art domain specific accelerator (DianNao), and fixed-function accelerators for MachSuite, Softbrain can match their performance with only 2x power overhead on average.
Plasticine
Authors: Prabhakar Raghu , Zhang Yaqi , Koeplinger David , Feldman Matt , Zhao Tian , Hadjis Stefan , Pedram Ardavan , Kozyrakis Christos , Olukotun Kunle
Published: September 2017

Reconfigurable architectures have gained popularity in recent years as they allow the design of energy-efficient accelerators. Fine-grain fabrics (e.g. FPGAs) have traditionally suffered from performance and power inefficiencies due to bit-level reconfigurable abstractions. Both fine-grain and coarse-grain architectures (e.g. CGRAs) traditionally require low level programming and suffer from long compilation times. We address both challenges with Plasticine, a new spatially reconfigurable architecture designed to efficiently execute applications composed of parallel patterns. Parallel patterns have emerged from recent research on parallel programming as powerful, high-level abstractions that can elegantly capture data locality, memory access patterns, and parallelism across a wide range of dense and sparse applications.

We motivate Plasticine by first observing key application characteristics captured by parallel patterns that are amenable to hardware acceleration, such as hierarchical parallelism, data locality, memory access patterns, and control flow. Based on these observations, we architect Plasticine as a collection of Pattern Compute Units and Pattern Memory Units. Pattern Compute Units are multi-stage pipelines of reconfigurable SIMD functional units that can efficiently execute nested patterns. Data locality is exploited in Pattern Memory Units using banked scratchpad memories and configurable address decoders. Multiple on-chip address generators and scatter-gather engines make efficient use of DRAM bandwidth by supporting a large number of outstanding memory requests, memory coalescing, and burst mode for dense accesses. Plasticine has an area footprint of 113 mm2 in a 28nm process, and consumes a maximum power of 49 W at a 1 GHz clock. Using a cycle-accurate simulator, we demonstrate that Plasticine provides an improvement of up to 76.9x in performance-per-Watt over a conventional FPGA over a wide range of dense and sparse applications.
Neuroimmune interaction and the regulation of intestinal immune homeostasis
Authors: Verheijden Simon , Boeckxstaens Guy E.
Published: September 2017

Many essential gastrointestinal functions, including motility, secretion, and blood flow, are regulated by the autonomic nervous system (ANS), both through intrinsic enteric neurons and extrinsic (sympathetic and parasympathetic) innervation. Recently identified neuroimmune mechanisms, in particular the interplay between enteric neurons and muscularis macrophages, are now considered to be essential for fine-tuning peristalsis. These findings shed new light on how intestinal immune cells can support enteric nervous function. In addition, both intrinsic and extrinsic neural mechanisms control intestinal immune homeostasis in different layers of the intestine, mainly by affecting macrophage activation through neurotransmitter release. In this mini-review, we discuss recent insights on immunomodulation by intrinsic enteric neurons and extrinsic innervation, with a particular focus on intestinal macrophages. In addition, we discuss the relevance of these novel mechanisms for intestinal immune homeostasis in physiological and pathological conditions, mainly focusing on motility disorders (gastroparesis and postoperative ileus) and inflammatory disorders (colitis).
Tissue-, sex-, and age-specific DNA methylation of rat glucocorticoid receptor gene promoter and insulin-like growth factor 2 imprinting control region
Authors: Agba Ogechukwu Brenda , Lausser Ludwig , Huse Klaus , Bergmeier Christoph , Jahn Niels , Groth Marco , Bens Martin , Sahm Arne , Gall Maria , Witte Otto W. , Kestler Hans A. , Schwab Matthias , Platzer Matthias
Published: September 2017

Tissue-, sex-, and age-specific epigenetic modifications such as DNA methylation are largely unknown. Changes in DNA methylation of the glucocorticoid receptor gene ( NR3C1) and imprinting control region (ICR) of IGF2 and H19 genes during the lifespan are particularly interesting since these genes are susceptible to epigenetic modifications by prenatal stress or malnutrition. They are important regulators of development and aging. Methylation changes of NR3C1 affect glucocorticoid receptor expression, which is associated with stress sensitivity and stress-related diseases predominantly occurring during aging. Methylation changes of IGF2/H19 affect growth trajectory and nutrient use with risk of metabolic syndrome. Using a locus-specific approach, we characterized DNA methylation patterns of different Nr3c1 promoters and Igf2/H19 ICR in seven tissues of rats at 3, 9, and 24 mo of age. We found a complex pattern of locus-, tissue-, sex-, and age-specific DNA methylation. Tissue-specific methylation was most prominent at the shores of the Nr3c1 CpG island (CGI). Sex-specific differences in methylation peaked at 9 mo. During aging, Nr3c1 predominantly displayed hypomethylation mainly in females and at shores, whereas hypermethylation occurred within the CGI. Igf2/H19 ICR exhibited age-related hypomethylation occurring mainly in males. Methylation patterns of Nr3c1 in the skin correlated with those in the cortex, hippocampus, and hypothalamus. Skin may serve as proxy for methylation changes in central parts of the hypothalamic-pituitary-adrenal axis and hence for vulnerability to stress- and age-associated diseases. Thus, we provide in-depth insight into the complex DNA methylation changes of rat Nr3c1 and Igf2/H19 during aging that are tissue and sex specific.
Non-Discriminant Relationships between Leg Muscle Strength, Mass and Gait Performance in Healthy Young and Old Adults
Authors: Muehlbauer Thomas , Granacher Urs , Borde Ron , Hortobágyi Tibor
Published: September 2017

Background: Gait speed declines with increasing age, but it is unclear if gait speed preferentially correlates with leg muscle strength or mass. Objective: We determined the relationship between gait speed and (1) leg muscle strength measured at 3 lower extremity joints and (2) leg lean tissue mass (LTM) in healthy young (age: 25 years, n = 20) and old (age: 70 years, n = 20) adults. Methods: Subjects were tested for maximal isokinetic hip, knee, and ankle extension torque, leg LTM by bioimpedance, and gait performance (i.e., gait speed, stride length) at preferred and maximal gait speeds. Results: We found no evidence for a preferential relationship between gait performance and leg muscle strength compared with gait performance and leg LTM in healthy young and old adults. In old adults, hip extensor strength only predicted habitual gait speed (R2 = 0.29, p = 0.015), whereas ankle plantarflexion strength only predicted maximal gait speed and stride length (both R2 = 0.40, p = 0.003). Conclusions: Gait speed did not preferentially correlate with leg muscle strength or leg LTM, favoring neither outcome for predicting mobility. Thus, we recommend that both leg muscle strength and leg LTM should be tested and trained complementarily. Further, hip and ankle extension torque predicted gait performance, and thus we recommend to test and train healthy old adults by functional integrated multiarticular rather than monoarticular lower extremity strength exercises.
Safety of Monitored Anesthesia Care Using Propofol-Based Sedation for Pleuroscopy
Authors: Vakil Erik , Sarkiss Mona , Ost David , Vial Macarena R. , Casal Roberto F. , Eapen Georgie A. , Grosu Horiana B.
Published: September 2017

Background: The optimal approach to sedation for pleuroscopy remains undefined. Propofol is the favored sedative-hypnotic for many proceduralists but has a narrow therapeutic window and the risk for oversedation is high. Propofol-based sedation administered by anesthesiologists and the routine use of end-tidal capnography and bispectral index (BIS) monitoring may attenuate risks of complications. Objectives: The purpose of our study was to evaluate the safety and efficacy of monitored anesthesia care for pleuroscopy. Methods: We conducted a retrospective cohort study of patients who underwent pleuroscopy. The primary outcome of interest was the incidence of anesthesia complications in patients undergoing pleuroscopy. Hypoxia was defined as oxygen saturation of less than 90% for 2 min and hypotension was defined as the need for vasopressors. Results: Of 199 enrolled patients, there were no significant complications attributed directly to anesthesia. Minor complications included hypoxia in 9 patients (4.5%), hypotension in 76 patients (38.2%), and insertion of a nasopharyngeal tube airway in 2 patients (1.0%). There was no significant difference in anesthesia-related complications between those with BIS monitoring and those without. Lower mean oxygen saturations (p = 0.028) and hypoxia (p = 0.021) were found in patients receiving the combination of propofol plus narcotics plus sedatives compared to those receiving propofol only, propofol plus narcotics or propofol plus sedatives. Conclusion: Our study demonstrates that pleuroscopy using propofol with end-tidal capnography monitoring, with or without BIS monitoring, is safe and effective. The combination of propofol with narcotics and sedatives is associated with more hypoxia and lower mean oxygen saturation compared with propofol alone, propofol plus narcotics or propofol plus sedatives.
The Modern Art of Reading Computed Tomography Images of the Lungs: Quantitative CT
Authors: Herth Felix J.F. , Kirby Miranda , Sieren Jered , Herth Jonas , Schirm Joshua , Wood Susan , Schuhmann Maren
Published: September 2017

Lung diseases are increasing in prevalence and overall burden worldwide. To stem the tide, more and more national and international guidelines are recommending the use of various diagnostic algorithms that are disease specific. There is growing consensus among the respiratory community that although patient histories and lung function testing are the minimum required for clinical examinations, these tests alone are not sufficient for disease characterization. Therefore, the use of computed tomography (CT) imaging is increasing used in clinical decision making for lung diseases. Lung diseases affect various components of lung, including the small airways, lung parenchyma, the interstitial space and the pulmonary vasculature. Quantitative CT (QCT) methods are emerging and are increasingly available using commercial software to quantify the underlying disease components, and a growing body of evidence suggests that QCT is an important tool in the clinical setting to help accurately and reproducibly detect where the disease is located in the lung, and to quantify the extent and overall severity for several lung diseases. Furthermore, this growing body of evidence has promoted the use of thoracic QCT to the point that it is now considered by many as an indispensable technology for longitudinal analysis and intervention trials. Many QCT imaging measurements are available to the respiratory physician, and the aim of this review is to introduce and describe pulmonary QCT imaging measurements and methodologies.
Bats in settlements from an atlantic forest area in northeastern Brazil
Authors: Zeppelini Caio Graco , Rego Karlla Morganna Costa , Lopez Luiz Carlos Serramo
Published: September 2017

Bats are key components of ecological networks, and studies in degraded areas are especially important to understand the impact of the human settlements on bats communities. Here, we surveyed the bat fauna in Guaribas Biological Reserve, a protected area in the Atlantic Forest in Paraiba state, northeastern Brazil, and compared it with the bat fauna that occupies the nearby villages. In the villages, we recorded 650 individuals from 14 species, while 1,127 individuals from 20 species were recorded in the Reserve. Diversity estimation pointed out 19 species for the settlements, and 22 for the Reserve. A Bray-Curtis/Sorensen similarity cluster analysis informed that the Reserve areas and the villages form two distinct groups. Additionally, a Wilcox test pointed out that both areas have significantly distinct abundances and species richnesses. Only a subset of the assemblage, mainly formed by generalist or opportunist species, occupies the villages, exploring resources that are offered by human activities.
Verbenaceae J.St.-Hil. do Parque Estadual do Ibitipoca, Minas Gerais, Brasil
Authors: Cruz Ludymila Viana Valadares , Salimena Fátima Regina Gonçalves
Published: September 2017

O Parque Estadual do Ibitipoca (PEIB) faz parte do Complexo da Mantiqueira situado no sudeste da Zona da Mata Mineira e inserido no Domínio Atlântico, com predomínio dos campos rupestres, em altitudes entre 1000 e 1784 m. Este trabalho apresenta o estudo da família Verbenaceae na área, onde foram encontrados quatro gêneros e nove espécies: Lantana camara, L. fucata, Lippia hermannioides, L. lupulina, L. origanoides, Stachytarpheta sellowiana, Verbena bonariensis, V. hirta e V. litoralis. Registros recentes de L. hermannioides e S. sellowiana não foram encontrados e as coleções destas espécies datam de mais de 45 e 120 anos de ocorrência na área, respectivamente. Stachytarpheta sellowiana é considerada criticamente ameaçada e com ocorrência restrita para a região Sul da Serra da Mantiqueira.
Phylogenetic relationships, taxonomic revision and new taxa of Termitomyces (Lyophyllaceae, Basidiomycota) inferred from combined nLSU- and mtSSU-rDNA sequences
Authors: MOSSEBO D.C. , ESSOUMAN E.P.F. , MACHOUART M.C. , GUEIDAN C.
Published: September 2017

In order to contribute to the taxonomic revision of several species of Termitomyces, sequences of 74 strains representing 28 taxa were used to generate a combined nLSU-mtSSU phylogenetic tree. The phylogenetic analysis showed that re-classification was required for 12 taxa originally misidentified under various names. The changes led to the use of 8 valid names for these 12 taxa, including two new forms: T. striatus f. subclypeatus and T. medius f. ochraceus; and a new combination: Termitomyces brunneopileatus according to their placement on various clades and subclades in the phylogenetic trees. Termitomyces letestui and T. medius were taxonomically revised. In addition,    T. letestui collected from China is the first record from the Asian continent. This species was so far collected only in tropical Africa. Similarly, T. robustus is reported for the first time from Cameroon. Moreover, the phylogenetic analysis confirms T. subumkowaan as a new species that was originally described only on the basis of morphological features. The combined phylogenetic analysis and morphological features reveal that different strains of the same taxon show sometimes large variations in macro- and micromorphological features, some very likely with links to genetic factors other than genes sequenced here, thereby justifying the new forms erected within these taxa in order to facilitate their identification.
Two new species of Impatiens (Balsaminaceae) from Putao, Kachin State, northern Myanmar
Authors: YANG BIN , ZHOU SHI-SHUN , MAUNG KYAW WIN , TAN YUN-HONG
Published: September 2017

Two new species of the genus Impatiens (Balsaminaceae) from Putao, Kachin State, Myanmar, are here described and illustrated. Impatiens casseabriae can be easily recognized by its narrowly elliptic to narrowly oblanceolate leaves, petioles up to 3 mm long, lower lateral united petals 25–40 mm long. Impatiens putaoensis differs from its closely related species I. xanthina in having light greenish yellow flowers, lateral sepals ovate to elliptic, lower lobe of united petals semilunar, upper lobe of united petals dolabrate, dorsal petal ovate to nearly orbicular, with a narrow inconspicuous dorsal crest. Molecular phylogenetic analyses of sequences from both nuclear ribosomal and plastidgenes confirm that the two new species are distinct from previously recorded species.
Combining morphology and population genetic analysis uncover species delimitation in the widespread African tree genus Santiria (Burseraceae)
Authors: IKABANGA DAVY U. , STÉVART TARIQ , KOFFI K. GUILLAUME , KAMENI MONTHÉ FRANCK , NZIGOU DOUBINDOU ELIE C. , DAUBY GILLES , SOUZA ALAIN , M’BATCHI BERTRAND , HARDY OLIVIER J.
Published: September 2017

Taxonomic classification based on morphology alone can prove difficult. This is the case of the polymorphic forest tree species Santiria trimera in Africa, whose classification has remained controversial for over a century. Studies combining chloroplast and nuclear DNA sequences show the existence of several phylogenetic clades in this taxon, with some occurring in sympatry in western Central Africa suggesting the existence of at least two species. By combining genetic and morphological markers, we aim to assess the species delimitation in the Santiria species complex. Morphological trait (trunk, leaflet, flower and fruit characteristics) analysis using 223 standing individuals and 103 herbarium samples were combined with genetic analyses using 479 individuals genotyped at eight microsatellite markers. Genetic clusters were identified using Bayesian assignment in order to delimit species following the Biological Species Concept and to identify distinctive characters from morphometric analyses in retrospect. Three genetic clusters were identified and found to occur in sympatry. The type of inflorescence and the colour of unripe fruit were the most discriminant morphological traits among those genetic clusters, while many quantitative traits showed overlapping distributions between genetic clusters and explain the difficulty encountered by previous botanists to resolve the taxonomy of Santiria. The combination of genetic and morphological data suggests the presence of three species within the taxon Santiria trimera from western Central Africa. This work should guide a taxonomic revision within the genus Santiria in Africa.
A new species of manakin (Aves: Pipridae; Machaeropterus) from Peru with a taxonomic reassessment of the Striped Manakin (M. regulus) complex
Authors: LANE DANIEL F. , KRATTER ANDREW W. , O’NEILL JOHN P.
Published: September 2017

We describe a new taxon of manakin in the Machaeropterus regulus complex, from the foothills of southwestern Loreto and northern San Martín departments, Peru. This new form appears to be almost identical morphologically to the Tepui form M. regulus aureopectus but differs strongly from that and all other members of the M. regulus complex in voice. Therefore, we conclude that this population represents a new biological species that we here name Machaeropterus eckelberryi. Based on voice and some morphological characters, we concur with several previous authors (e.g., Whittaker & Oren 1999; Snow 2004; Ridgely & Tudor 2009) that nominate M. regulus (Eastern Striped Manakin), of the Atlantic Forest of Brazil, should be separated as a biological species from the polytypic Machaeropterus striolatus of western South America (Western Striped Manakin), including M. s. striolatus of Amazonia, M. r. obscurostriatus and M. r. zulianus of the Venezuelan Andes, M. r. antioquiae of the Colombian Andes, and M. r. aureopectus of the tepuis region.