bluuebunny/crossref_metadata_2025 huggingface dataset:
ACM Queue
Authors: Grossman Edward
Published: August 2005

I am the Editor of Queue (http://www.acmqueue.org), ACM's recently launched magazine geared towards practicing software developers and architects. We have a great editorial advisory board, including industry giants such as Steve Bourne, Eric Allman, and Jim Gray.We have a special report on "Gaming Technology and Issues" coming up. We are looking for people who might be interested in writing for this issue.We would be entirely open on article ideas for this or upcoming issues. Queue is not a "here's the latest product from company X" magazine -- we are more in-depth, focusing on core technologies themselves, how they affect software developers. Obviously gaming is an area that has a huge impact far beyond just the gaming industry. We want to share what is happening at the cutting edge with our audience.
Interview with Alan Kay
Authors: Kay Alan
Published: August 2005

The legendary Alan Kay and Roy E. Disney have graciously appeared on camera for interviews and joined the ACM Computers in Entertainment magazine's editorial board. Alan and Roy are two of the nicest people to talk to and work with. Alan talked about soft fun versus hard fun, and his research on Squeak for enhancing and amplifying learning in children's education. Roy told us about educators versus entertainers, and his views on traditional and CGI animations. The video clips of the interviews are available at http://www.acm.org/pubs/cie/oct2003/index.htmlAlan Kay, HP Fellow and President of Viewpoints Research Institute, is best known for the idea of personal computing the conception of the intimate laptop computer, and the inventions of the now ubiquitous overlapping-window interface and modern object-oriented programming. His deep interests in children and education were the catalyst for these ideas, and they continue to be a major source of inspiration. In the past, Alan has been a Xerox Fellow, Chief Scientist of Atari, Apple Fellow, and Disney Fellow. More information is available at http://www.squeakland.org/community/biography/alanbio.html and http://www.viewpointsresearch.org/alan.html
Towards digital narrative for children
Authors: Madej Krystina
Published: August 2005

Narrative is central to human experience, and a key way that experience is made meaningful. Education and entertainment have both played a significant part in the evolution of children's narrative. In its liminal state during the 1500s, children's print narrative was primarily educational. Locke's theories of education in the 1700s encouraged "children playing and doing as children," and narrative slowly moved towards being entertaining as well as educational. Not until the 1800s, with the stories of Lewis Carroll, was narrative created solely for the entertainment of children. Throughout its development it has provided a way for shaping children's experience, reflecting how they fit into their society, and helping them construct meaning for themselves. As narrative evolved to find its rightful place in the mix of technology, education, and entertainment within children's print culture, so it is evolving within the rapidly developing digital environment. Authors, publishers, and producers are responsible for understanding how children respond to a digital environment, and for making the digital narrative a positive experience. This paper presents the history of children's literature as it has developed from oral tradition through print and now into digital environments. It draws parallels, particularly between education and entertainment, in children's print narratives and similar (but more rapid) developments in the evolution of digital narratives. In doing so, it aims to encourage a more positive attitude to the significant opportunities new technologies offer for reshaping the way in which narrative for children is conceived and presented so that it continues in its time honored role of constructing meaning in their lives.
Wildlife rescue as a framework for learning
Authors: Romero Christopher
Published: August 2005

Nickelodeon Online has designed and deployed two versions of "Wildlife Rescue", an online game that allows kids to take on the role of a Wildlife Ranger. Rangers are charged with the responsibility of attending to animals who have become sick or injured in locales such as the Serengeti or an island in the South China Sea. We feel that this game which is part simulation and part real-time strategy presents an effective and popular framework for learning about animals, biodiversity and conservation and we describe some of the cognitive instruments used to engage our audience about these topics.
Energy efficient wireless packet scheduling and fair queuing
Authors: Raghunathan Vijay , Ganeriwal Saurabh , Srivastava Mani , Schurgers Curt
Published: August 2005

As embedded systems are being networked, often wirelessly, an increasingly larger share of their total energy budget is due to the communication. This necessitates the development of power management techniques that address communication subsystems, such as radios, as opposed to computation subsystems, such as embedded processors, to which most of the research effort thus far has been devoted. In this paper, we present techniques for energy efficient packet scheduling and fair queuing in wireless communication systems. Our techniques are based on an extensive slack management approach that dynamically adapts the output rate of the system in accordance with the input packet arrival rate. We use a recently proposed radio power management technique, dynamic modulation scaling (DMS), as a control knob to enable energy-latency trade-offs during wireless packet transmission. We first analyze a single input stream scenario, and describe a rate adaptation technique that results in significantly lower energy consumption (reductions of up to 10 ×), while still bounding the resulting packet delays. By appropriately setting the various parameters of our algorithm, the system can be made to traverse the energy-latency-fidelity trade-off space. We extend our techniques to a multiple input stream scenario, and present
E
2
WFQ
, an energy efficient version of the weighted fair queuing (WFQ) algorithm for fair packet scheduling. Simulation results show that large energy savings can be obtained through the use of
E
2
WFQ
, with only a small, bounded increase in worst case packet latency. Further, our results demonstrate that
E
2
WFQ
does not adversely affect the throughput allocation (and hence, fairness) of WFQ.
Sensor deployment and target localization in distributed sensor networks
Authors: Zou Yi , Chakrabarty Krishnendu
Published: August 2005

The effectiveness of cluster-based distributed sensor networks depends to a large extent on the coverage provided by the sensor deployment. We propose a virtual force algorithm (VFA) as a sensor deployment strategy to enhance the coverage after an initial random placement of sensors. For a given number of sensors, the VFA algorithm attempts to maximize the sensor field coverage. A judicious combination of attractive and repulsive forces is used to determine the new sensor locations that improve the coverage. Once the effective sensor positions are identified, a one-time movement with energy consideration incorporated is carried out, that is, the sensors are redeployed, to these positions. We also propose a novel probabilistic target localization algorithm that is executed by the cluster head. The localization results are used by the cluster head to query only a few sensors (out of those that report the presence of a target) for more detailed information. Simulation results are presented to demonstrate the effectiveness of the proposed approach.
Energy savings and speedups from partitioning critical software loops to hardware in embedded systems
Authors: Stitt Greg , Vahid Frank , Nematbakhsh Shawn
Published: August 2005

We present results of extensive hardware/software partitioning experiments on numerous benchmarks. We describe our loop-oriented partitioning methodology for moving critical code from hardware to software. Our benchmarks included programs from PowerStone, MediaBench, and NetBench. Our experiments included estimated results for partitioning using an 8051 8-bit microcontroller or a 32-bit MIPS microprocessor for the software, and using on-chip configurable logic or custom application-specific integrated circuit hardware for the hardware. Additional experiments involved actual measurements taken from several physical implementations of hardware/software partitionings on real single-chip microprocessor/configurable-logic devices. We also estimated results assuming voltage scalable processors. We provide performance, energy, and size data for all of the experiments. We found that the benchmarks spent an average of 80% of their execution time in only 3% of their code, amounting to only about 200 bytes of critical code. For various experiments, we found that moving critical code to hardware resulted in average speedups of 3 to 5 and average energy savings of 35% to 70%, with average hardware requirements of only 5000 to 10,000 gates. To our knowledge, these experiments represent the most comprehensive hardware/software partitioning study published to date.
Call for papers
Authors: Lee Newton
Published: August 2005

GUIDELINE FOR AUTHORS

Papers should be submitted to the editor-in-chief via email,
preferably in MS Word or RTF format. Rich media such as QuickTime
and Flash movies are also acceptable. Manuscripts should contain no
more than 10,000 words. Submissions should include the paper title,
abstract, keywords, classification
(www.acm.org/class/1998/overview.html), name of authors, their
affiliation, email address, and postal address.
Acknowledgements
Authors: Lee Newton
Published: August 2005

Issue Acknowledgements

Flash homepage design volunteers
— Alex Lieu, Johnny Rodriguez, Michael Borys— 3-Pin Media

Flash animation volunteers
— Jay Popeski, Jeffrey Blyseth— Axis Graphics

Video recording volunteers
— Brett Hardin, Eric Huff

Video and sound editing volunteers
— Eric Huff

Proofreading volunteer
— Cathy Georges

Student volunteer
— Laura Knight

Producer and editor-in-chief
— Newton Lee

Also thanks to all authors, interviewees, reviewers, editorial board advisors, Mark Mandelbaum, John White, Roma Simon, Irma Strolia, and the entire ACM staff for their support.
ACM SIGCHI international conference on advances in computer entertainment technology
Authors: Cheok Adrian David
Published: August 2005

ACM SIGCHI International Conference on Advances in Computer Entertainment Technology— ACE 2004

Dear Editor,

As we know, the field of computer entertainment technology has aroused great interest recently amongst researchers and developers in both academic and industrial/business fields as it is duly recognized as showing high promise of bringing on exciting new forms of human computer interaction. Now deemed deserving of both serious academic research, as well as major industry and business uptake, techniques used in computer entertainment are also seen to translate into advances in research work ranging from industrial training, collaborative work, novel interfaces, novel multimedia, network computing and ubiquitous computing.

Hence, in June 2004 there will be a conference entitled the ACM SIGCHI International Conference on Advances in Computer Entertainment Technology ACE 2004. The purpose of this conference is to bring together academic and industry researchers, as well as computer entertainment developers and practitioners, to address and advance the research and development issues related to computer entertainment.

It will fulfill the need for a conference which satisfies the needs of both the academic researcher to have a formal and rigorous peer-review forum for publication, as well as the industry professional wanting to have updated information on topics which address hard research issues which are not possible to explore in the day-to-day commercial environment. Furthermore active demo, exhibition, and poster sessions will provide an exciting interchange between researchers and practitioners.

ACM, will be publishing all accepted papers in the proceedings, and the conference is fully sponsored by ACM SIGCHI. A program committee comprising over 60 of the leading researchers in the field will be reviewing the submissions. To recognize outstanding research in the field, there will be various prizes and awards given for the most outstanding submissions. Furthermore, the top papers will be selected for revision and review for the leading publication ACM Computers in Entertainment Magazine.

The following, non exclusive, topics are called for: Computer Entertainment and: Art and Media, Augmented / Mixed Reality, Avatars and Virtual Action, Evolutionary Platforms / Hardware, Graphics Techniques, Haptics, Interfaces, Military Training / Simulation Applications of Games, Mobile Entertainment, Mobile Phones, Narratives, Networking, New Genres, New Standards, Novel Hardware Devices, Physics / AI, Social Computing, Sound and Music.

Prospective authors are now invited to submit Papers/Posters/Demos electronically via the conference website http://www.ace2004.org by 5th February 2004

Sincerely,

Adrian David Cheok

National University of Singapore
Computer game studies at Northumbria University
Authors: Kirkpatrick Graeme
Published: August 2005

At Northumbria University we have set up what we believe is the
only dedicated Master of Arts degree in Computer Game Studies.
People who have played games for a long time, or have worked in the
industry might see an opportunity here to reflect on their
activities and to use humanities tools (literary analysis; cultural
theory etc.) to explore its significance in their lives and in
society as a whole.
Interviews with Quincy Jones
Authors: Jones Quincy
Published: August 2005

The legendary Quincy Jones and Seymour Papert have graciously
appeared on camera for interviews and joined the ACM Computers in
Entertainment magazines editorial board. Quincy and Seymour are two
of the nicest people to talk to and work with. Quincy talks about
education as fun learning, the impact of music on children, how
technology affects the way music is created and produced, and
digital distribution of music over the Internet. Seymour speaks of
learning-rich entertainment, Logo and computer programming for
children, technology in schools and education, and the future of
home schooling and learning environments. The video clips of the
interviews are available at
http://www.acm.org/pubs/cie/mar2004/index.html

Quincy Jones, who composed more than 50 major motion picture and
television scores, has earned international acclaim as producer of
the best-selling single of all time and the best-selling album in
the history of the recording industry. The all-time most nominated
Grammy artist with a total of 76 nominations and 26 awards, Quincy
has also received an Emmy Award, seven Oscar nominations, and the
Academy of Motion Picture Arts and Sciences Jean Hersholt
Humanitarian Award. More information can be found at
http://www.quincyjonesmusic.com

Seymour Papert, a mathematician and an early pioneer of
Artificial Intelligence, is internationally recognized as the
seminal thinker on how computers can change learning. He is a
cofounder with Marvin Minsky of the AI Lab at MIT and a founding
faculty member of the MIT Media Lab, where he continues to work.
Seymour collaborated for many years with Jean Piaget at the
University of Geneva in Switzerland. He wrote many books including
Mindstorms: Children, Computers, and Powerful Ideas. More
information can be found at http://www.papert.org/
Think science!
Authors: Ritterfeld Ute , Weber Rene , Fernandes Sangeeta , Vorderer Peter
Published: August 2005

In February 2003, the JASON Foundation for Education supported
an interactive show, the Immersion Institutes Exploration: Sea
Lions, intended to enhance childrens understanding of
science; it played at three different theaters throughout the US.
The production, provided by Immersion Studios Inc., involved about
2000 students, mostly from ages 9 to 14. During the two-week event,
a random sample of students and their teachers participated in an
assessment of the show, including aspects of usability,
entertainment experience, and impact on learning. About a month
later, a follow-up was undertaken to complete the evaluation.

Results demonstrate that the show was highly appreciated by both
the participating students and teachers: The usability aspect of
the show was satisfying; the technology was found to be suitable
for all age groups involved, and the entertainment experience was
clearly intense. Students reported a high learning impact; this
opinion was reinforced by the teachers. The follow-up results,
however, did not provide proof of long-lasting recall of facts
embedded in the show. But it did provide some surprising evidence
that students gained detailed knowledge about show-related facts,
raising the question whether such a show can be used to make
students become more interested in a topic.
Edutainment
Authors: Egloff Tammie Hutto
Published: August 2005

With recent growth of the childrens software sector, companies are
pushing to create innovative software packages for home and school.
Edutainmentsoftware intended to educate children through the use of
entertainmentis one of the quickest growing sectors in the
children's software field. This exploratory study investigated how
children interacted with two new games that combine hands-on
computer input devices with software: the Easy Bake Oven PlaySet"
and the Tonka Workshop" PlaySet. Children were observed in order to
study their behavior patterns and preferences concerning the new
toys. Data collected describes participants preferences, ergonomics
difficulties, and software understanding. This initial research
suggested that: (1) childrens gender was uncorrelated with their
interaction or preferences; (2) childrens age was correlated with
their ability to use and understand the software and playset; and
(3) knowledge learned while using one playset transferred to the
second playset. These results open the door for further research
into gender issues, ergonomics, metaphor understanding,
learnability, and the ability of young children to use and
understand the physical and virtual worlds of the playsets.
Amusing ourselves to life
Authors: Rose Kim
Published: August 2005

In this article I feel compelled to pay tribute to one of my
mentors, Neil Postman, who passed away in October 2003. As a
student of and believer in much of Postmans philosophy, it is my
desire to help carry his legacy through my work and strive to
create ways in which to amuse ourselves to life.
Reducing instruction cache energy consumption using a compiler-based strategy
Authors: Zhang W. , Hu J. S. , Degalahal V. , Kandemir M. , Vijaykrishnan N. , Irwin M. J.
Published: August 2005

Excessive power consumption is widely considered as a major impediment to designing future microprocessors. With the continued scaling down of threshold voltages, the power consumed due to leaky memory cells in on-chip caches will constitute a significant portion of the processor's power budget. This work focuses on reducing the leakage energy consumed in the instruction cache using a compiler-directed approach.We present and analyze two compiler-based strategies termed as conservative and optimistic. The conservative approach does not put a cache line into a low leakage mode until it is certain that the current instruction in it is dead. On the other hand, the optimistic approach places a cache line in low leakage mode if it detects that the next access to the instruction will occur only after a long gap. We evaluate different optimization alternatives by combining the compiler strategies with state-preserving and state-destroying leakage control mechanisms. We also evaluate the sensitivity of these optimizations to different high-level compiler transformations, energy parameters, and soft errors.
An optimal algorithm for minimizing run-time reconfiguration delay
Authors: Ghiasi Soheil , Nahapetian Ani , Sarrafzadeh Majid
Published: August 2005

Reconfiguration delay is one of the major barriers in the way of dynamically adapting a system to its application requirements. The run-time reconfiguration delay is quite comparable to the application latency for many classes of applications and might even dominate the application run-time. In this paper, we present an efficient optimal algorithm for minimizing the run-time reconfiguration (context switching) delay of executing an application on a dynamically adaptable system. The system is composed of a number of cameras with embedded reconfigurable resources collaborating in order to track an object. The operations required to execute in order to track the object are revealed to the system at run-time and can change according to a number of parameters, such as the target shape and proximity. Similarly, we can assume that the applications comprising tasks are already scheduled and each of them has to be realized on the reconfigurable fabric in order to be executed.The modeling and the algorithm are both applicable to partially reconfigurable platforms as well as multi-FPGA systems. The algorithm can be directly applied to minimize the application run-time for the typical classes of applications, where the actual execution delay of the basic operations is negligible compared to the reconfiguration delay. We prove the optimality and the efficiency of our algorithm. We report the experimental results, which demonstrate a 2.5--40% improvement on the total run-time reconfiguration delay as compared to other heuristics.
The design of dynamically reconfigurable datapath coprocessors
Authors: Huang Zhining , Malik Sharad , Moreano Nahri , Araujo Guido
Published: August 2005

Increasing nonrecurring engineering and mask costs are making it harder to turn to hardwired application specific integrated circuit (ASIC) solutions for high-performance applications. The volume required to amortize these high costs has been increasing, making it increasingly expensive to afford ASIC solutions for medium-volume products. This has led to designers seeking programmable solutions of varying sorts using these so-called programmable platforms. These programmable platforms span a large range from bit-level programmable field programmable gate arrays to word-level programmable application-specific, and in some cases even general-purpose processors. The programmability comes with a power and performance overhead. Attempts to reduce this overhead typically involve making some core hardwired ASIC like logic blocks accessible to the programmable elements. This paper presents one such hybrid solution in this space---a relatively simple processor with a dynamically reconfigurable datapath acting as an accelerating coprocessor. This datapath consists of hardwired function units and reconfigurable interconnect. We present a methodology for the design of these solutions and illustrate it with two complete case studies: an MPEG2 coder, and a GSM coder, to show how significant speedups can be obtained using relatively little hardware. This work is part of the MESCAL project, which is geared towards developing design environments for the development of application-specific platforms.
Multitasking on reconfigurable architectures: microarchitecture support and dynamic scheduling
Authors: Noguera Juanjo , Badia Rosa M.
Published: August 2005

Dynamic scheduling for system-on-chip (SoC) platforms has become an important field of research due to the emerging range of applications with dynamic behavior (e.g., MPEG-4). Dynamically reconfigurable architectures are an interesting solution for this type of applications. Scheduling for dynamically reconfigurable architectures might be classified in two major broad categories: (1) static scheduling techniques or (2) use of an operating system (OS) for reconfigurable computing. However, research efforts demonstrate a trend to move tasks traditionally assigned to the OS into hardware (thus increasing performance and reducing power).In this paper, we introduce a methodology for dynamically reconfigurable architectures. The dynamic scheduling of tasks to several reconfigurable units is performed by a hardware-based multitasking support unit. Two different versions of the microarchitecture are possible (with or without a hardware configuration prefetch unit). The dynamic scheduling algorithms are also explained. Both algorithms try to minimize the reconfiguration overhead by overlapping the execution of tasks with device reconfigurations.An exhaustive study (using the developed simulation and performance analysis framework) of this novel proposal is presented, and the effect of the microarchitecture parameters has been studied. Results demonstrate the benefits of our approach (achieving similar performance to a static configuration solution but using half of the resources). The hardware configuration prefetch unit is useful (i.e., minimize the execution time) in applications with low level of parallelism.
Approximate minimum enclosing balls in high dimensions using core-sets
Authors: Kumar Piyush , Mitchell Joseph S. B. , Yildirim E. Alper
Published: August 2005

We study the minimum enclosing ball (MEB) problem for sets of points or balls in high dimensions. Using techniques of second-order cone programming and "core-sets", we have developed (1 + ε)-approximation algorithms that perform well in practice, especially for very high dimensions, in addition to having provable guarantees. We prove the existence of core-sets of sizeO(1/ε), improving the previous bound ofO(1/ε2), and we study empirically how the core-set size grows with dimension. We show that our algorithm, which is simple to implement, results in fast computation of nearly optimal solutions for point sets in much higher dimension than previously computable using exact techniques.
I/O-efficient point location using persistent B-trees
Authors: Arge Lars , Danner Andrew , Teh Sha-Mayn
Published: August 2005

We present an external planar point location data structure that is I/O-efficient both in theory and practice.The developed structure uses linear space and answers a query in optimal
O
(log

B
N

) I/Os, where
B
is the disk block size. It is based on a persistent B-tree, and all previously developed such structures assume a total order on the elements in the structure. As a theoretical result of independent interest, we show how to remove this assumption.Most previous theoretical I/O-efficient planar point location structures are relatively complicated and have not been implemented. Based on a bucket approach, Vahrenhold and Hinrichs therefore developed a simple and practical, but theoretically non-optimal, heuristic structure. We present an extensive experimental evaluation that shows that, on a range of real-world Geographic Information Systems (GIS) data, our structure uses a similar number of I/Os as the structure of Vahrenhold and Hinrichs to answer a query. On a synthetically generated worst-case dataset our structure uses significantly fewer I/Os.
A Combined Numerical and Experimental Study of Heat Transfer in a Roughened Square Channel with 45∘ Ribs
Authors: Taslim M. E. , Liu H.
Published: August 2005

Experimental investigations have shown that the
enhancement in heat transfer coefficients for air flow in a
channel roughened with low blockage (e/Dh < 0.1) angled ribs is
on the average higher than that roughened with 90∘ ribs
of the same geometry. Secondary flows generated by the angled ribs
are believed to be responsible for these higher heat transfer
coefficients. These secondary flows also create a spanwise
variation in the heat transfer coefficient on the roughened wall
with high levels of the heat transfer coefficient at one end of
the rib and low levels at the other end. In an effort to
investigate the thermal behavior of the angled ribs at elevated
Reynolds numbers, a combined numerical and experimental study was
conducted. In the numerical part, a square channel roughened with
45∘ ribs of four blockage ratios (e/Dh) of 0.10, 0.15, 0.20, and 0.25, each for a fixed pitch‐to‐height ratio
(P/e) of 10, was modeled. Sharp as well as round‐corner ribs
(r/e = 0 and 0.25) in a staggered arrangement were studied.
The numerical models contained the smooth entry and exit regions
to simulate exactly the tested geometries. A
pressure‐correction‐based, multiblock, multigrid,
unstructured/adaptive commercial software was used in this
investigation. Standard high Reynolds number k − ε

turbulence model in conjunction with the generalized wall
function for most parts was used for turbulence closure. The
applied thermal boundary conditions to the CFD models matched the
test boundary conditions. In the experimental part, a selected
number of these geometries were built and tested for heat
transfer coefficients at elevated Reynolds numbers up to
150 000, using a liquid crystal technique. Comparisons between
the test and numerically evaluated results showed reasonable
agreements between the two for most cases. Test results showed
that (a) 45∘ angled ribs with high blockage ratios
(>0.2) at elevated Reynolds numbers do not exhibit a good
thermal performance, that is, beyond this blockage ratio, the
heat transfer coefficient decreases with the rib blockage and (b)
CFD could be considered as a viable tool for the prediction of
heat transfer coefficients in a rib‐roughened test section.
Metabolic Syndrome and 10-Year Cardiovascular Disease Risk in the Hoorn Study
Authors: Dekker Jacqueline M. , Girman Cynthia , Rhodes Thomas , Nijpels Giel , Stehouwer Coen D.A. , Bouter Lex M. , Heine Robert J.
Published: August 2005

Background—

Different definitions of the metabolic syndrome have been proposed. Their value in a clinical setting to assess cardiovascular disease (CVD) risk is still unclear. We compared the definitions proposed by the National Cholesterol Education Program Adult Treatment Panel III (NCEP), World Health Organization (WHO), European Group for the Study of Insulin Resistance (EGIR), and American College of Endocrinology (ACE) with respect to the prevalence of the metabolic syndrome and the association with 10-year risk of fatal and nonfatal CVD.

Methods and Results—

The Hoorn Study is a population-based cohort study. The present study population comprised 615 men and 749 women aged 50 to 75 years and without diabetes or a history of CVD at baseline in 1989 to 1990. The prevalence of the metabolic syndrome at baseline ranged from 17% to 32%. The NCEP definition was associated with about a 2-fold increase in age-adjusted risk of fatal CVD in men and nonfatal CVD in women. For the WHO, EGIR, and ACE definitions, these hazard ratios were slightly lower. Risk increased with the number of risk factors. Elevated insulin levels were more prevalent in subjects with multiple risk factors, but metabolic syndrome definitions including elevated insulin level were not more strongly associated with risk.

Conclusions—

The metabolic syndrome, however defined, is associated with an approximate 2-fold increased risk of incident cardiovascular morbidity and mortality in a European population. In clinical practice, a more informative assessment can be obtained by taking into account the number of individual risk factors.
Metabolic Syndrome and Echocardiographic Left Ventricular Mass in Blacks
Authors: Burchfiel Cecil M. , Skelton Thomas N. , Andrew Michael E. , Garrison Robert J. , Arnett Donna K. , Jones Daniel W. , Taylor Herman A.
Published: August 2005

Background—

The metabolic syndrome has been associated with cardiovascular disease, but few studies have examined its relationship with subclinical measures such as echocardiographic left ventricular (LV) mass. This relationship is likely to be of particular importance in blacks, in whom both the metabolic syndrome and LV hypertrophy are common.

Methods and Results—

Echocardiography, performed at 1 of 4 sites in the Atherosclerosis Risk in Communities (ARIC) Study, was used to assess LV dimensions in 1572 black women and men aged 49 to 75 years in 1993–1996. Participants were categorized by number of metabolic syndrome characteristics (hypertension, dyslipidemia [low HDL cholesterol or high triglycerides], and glucose intolerance). Age-adjusted mean LV mass indexed by height (g/m) increased in a stepwise gradient with increasing number of metabolic syndrome disorders (none, any 1, any 2, all 3) in both women and men (125.1, 143.9, 153.7, 169.3 and 130.5, 148.7, 160.8, 170.2, respectively;
P
<0.001, tests for trend). Associations were diminished slightly by adjustment for smoking, alcohol intake, and education; additional adjustment for waist circumference resulted in some attenuation, but associations remained statistically significant. Analyses focusing on components of LV mass revealed that posterior wall and interventricular septal thickness, but not LV chamber size, were significantly and independently associated in general with the number of metabolic syndrome disorders. Consistent with these findings, relative wall thickness was also associated with number of disorders. Associations were similar across age and central adiposity. Hypertension had a strong influence on LV mass with additional contributions from dyslipidemia and glucose intolerance; strong synergistic effects of the syndrome beyond its individual components were not observed.

Conclusions—

In this cross-sectional population-based study of black women and men, the degree of metabolic syndrome clustering was strongly related to LV mass and its wall thickness components. These associations are consistent with a possible influence of underlying factors such as insulin resistance or other vascular processes on myocardial thickening and not on chamber size.
Intrathoracic Pressure Regulator During Continuous-Chest-Compression Advanced Cardiac Resuscitation Improves Vital Organ Perfusion Pressures in a Porcine Model of Cardiac Arrest
Authors: Yannopoulos Demetris , Nadkarni Vinay M. , McKnite Scott H. , Rao Anu , Kruger Kurt , Metzger Anja , Benditt David G. , Lurie Keith G.
Published: August 2005

Background—

A novel device, the intrathoracic pressure regulator (ITPR), combines an inspiratory impedance threshold device (ITD) with a vacuum source for the generation of controlled −10 mm Hg vacuum in the trachea during cardiopulmonary resuscitation (CPR) while allowing positive pressure ventilation. Compared with standard (STD) CPR, ITPR-CPR will enhance venous return, systemic arterial pressure, and vital organ perfusion in both porcine models of ventricular fibrillation and hypovolemic cardiac arrest.

Methods and Results—

In protocol 1, 20 pigs (weight, 30±0.5 kg) were randomized to STD-CPR or ITPR-CPR. After 8 minutes of untreated ventricular fibrillation, CPR was performed for 6 minutes at 100 compressions per minute and positive pressure ventilation (100% O
2
) with a compression-to-ventilation ratio of 15:2. In protocol 2, 6 animals were bled 50% of their blood volume. After 4 minutes of untreated ventricular fibrillation, interventions were performed for 2 minutes with STD-CPR and 2 minutes of ITPR-CPR. This sequence was repeated. In protocol 3, 6 animals after 8 minutes of untreated VF were treated with ITPR-CPR for 15 minutes, and arterial and venous blood gases were collected at baseline and minutes 5, 10, and 15 of CPR. A newer, leak-proof ITPR device was used. Aortic, right atrial, endotracheal pressure, intracranial pressure, and end-tidal CO
2
values were measured (mm Hg); common carotid arterial flow also was measured (mL/min). Coronary perfusion pressure (diastolic; aortic minus right atrial pressure) and cerebral perfusion pressure (mean arterial minus mean intracranial pressure) were calculated. Unpaired Student
t
test and Friedman’s repeated-measures ANOVA of ranks were used in protocols 1 and 3. A 2-tailed Wilcoxon signed-rank test was used for analysis in protocol 2. Fischer’s exact test was used for survival. Significance was set at
P
<0.05. Vital organ perfusion pressures and end-tidal CO
2
were significantly improved with ITPR-CPR in both protocols. In protocol 1, 1-hour survival was 100% with ITPR-CPR and 10% with STD-CPR (
P
=0.001). Arterial blood pH was significantly lower and Pa
co
2
was significantly higher with ITPR- CPR in protocol 1. Arterial oxygen saturation was 100% throughout the study in both protocols. Pa
co
2
and Pa
o
2
remained stable, but metabolic acidosis progressed, as expected, throughout the 15 minutes of CPR in protocol 3.

Conclusions—

Compared with STD-CPR, use of ITPR-CPR improved hemodynamics and short-term survival rates after cardiac arrest.
Instantaneous Wavelet Energetic Transfers between Atmospheric Blocking and Local Eddies
Authors: Fournier Aimé
Published: August 2005

A new wavelet energetics technique, based on best-shift orthonormal wavelet analysis (OWA) of an instantaneous synoptic map, is constructed for diagnosing nonlinear kinetic energy (KE) transfers in five observed blocking cases. At least 90% of the longitudinal variance of time and latitude band mean 50-kPa geopotential is reconstructed by only two wavelets using best shift. This superior efficiency to the standard OWAs persists for time-evolving structures. The cases comprise two categories, respectively dominated by zonal-wavenumber sets {1} and {1, 2}. Further OWA of instantaneous residual nonblocking structures, combined with new “nearness” criteria, yields three more orthogonal components, representing smaller-scale eddies near the block (upstream and downstream) and distant structures. This decomposition fulfills a vision expressed to the author by Saltzman. Such a decomposition is not obtainable by simple Fourier analysis.

Eddy patterns apparent in the components’ contours suggest inferring geostrophic energetic interactions, but the component Rossby numbers may be too large to support the inference. However, a new result enabled by this method is the instantaneous attribution of blocking strain-field effects to particular energetically interactive eddies, consistent with Shutts’ hypothesis. Such attribution was only possible before in simplified models or in a time-average sense. In four of five blocks, the upstream eddies feed KE to the block, which in turn, in three of four cases, transmits KE to the downstream eddies. The small case size precludes statistically significant conclusions. The appendixes link low-order blocking structure and dynamics to some wavelet design principles and propose a new interaction diagnosis, similar to E-vector analysis, but instantaneous.
Ocean Gyres and Abrupt Change in the Thermohaline Circulation: A Conceptual Analysis
Authors: Longworth Hannah , Marotzke Jochem , Stocker Thomas F.
Published: August 2005

The implications are investigated of representing ocean gyre circulations by a diffusion term in the Stommel and Rooth box models of the thermohaline circulation (THC) in one and two hemispheres, respectively. The approach includes mostly analytical solution and study of the bifurcation structure, but also numerical integration and feedback analysis. Sufficient diffusion (gyre strength) eliminates multiple equilibria from either model, highlighting the need for accurate gyre circulation strength in general circulation models (GCMs) when considering the potential for abrupt climate change associated with THC shutdown.

With diffusion, steady-state flow strength in the Rooth model depends on freshwater forcing (i.e., implied atmospheric water vapor transport) in both hemispheres, not only on that in the upwelling hemisphere, as in the nondiffusive case. With asymmetric freshwater forcing, two solutions (strong stable and weak unstable) are found with sinking in the hemisphere with stronger forcing and one solution with sinking in the other hemisphere. Under increased freshwater forcing the two solutions in the hemisphere with stronger forcing meet in a saddle-node bifurcation (if diffusion is sufficiently strong to prevent a subcritical Hopf bifurcation first), followed by flow reversal. Thus, the bifurcation structure with respect to freshwater forcing of the diffusive Rooth model of two-hemisphere THC is similar to that of the Stommel model of single-hemisphere THC, albeit with a very different dynamical interpretation. Gyre circulations stabilize high-latitude sinking in the Stommel model. In the Rooth model, gyre circulations only stabilize high-latitude sinking if the freshwater forcing is weaker in the sinking hemisphere than in the upwelling hemisphere, by an amount that increases with diffusion. The values of diffusion and freshwater forcing at which qualitative change in behavior occurs correspond to the range of the values used in and obtained with GCMs, suggesting that this analysis can provide a conceptual foundation for analyzing the stability of the interhemispheric THC, and also for the potential of the Atlantic THC to undergo abrupt change.
Arctic Tropospheric Winds Derived from TOVS Satellite Retrievals
Authors: Francis Jennifer A. , Hunter Elias , Zou Cheng-Zhi
Published: August 2005

Accurate three-dimensional wind fields are essential for diagnosing a variety of important climate processes in the Arctic, such as the advection and deposition of heat and moisture, changes in circulation features, and transport of trace constituents. In light of recent studies revealing significant biases in upper-level winds over the Arctic Ocean from reanalyses, new daily wind fields are generated from 22.5 yr of satellite-retrieved thermal-wind profiles, corrected with a recently developed mass-conservation scheme. Compared to wind measurements from rawinsondes during the Surface Heat Budget of the Arctic (SHEBA) experiment, biases in satellite-retrieved winds are near zero in the meridional direction, versus biases of over 50% for reanalyses. Errors in the zonal component are smaller than those observed in reanalysis winds in the upper troposphere, while in the lower troposphere the effects of Greenland introduce uncertainty in the mass-conservation calculation. Further reduction in error may be achieved by incorporating winds retrieved from feature-tracking techniques using satellite imagers. Overall, satellite-retrieved winds are superior to reanalysis products over the data-sparse Arctic Ocean and provide increased accuracy for analyses requiring wind information.

Trends and anomalies for the 22.5-yr record are calculated for both meridional and zonal winds at eight levels between the surface and 300 hPa. Annual mean trends are similar at varying levels, reflecting the relatively barotropic nature of the Arctic troposphere. Zonal winds are more westerly over Eurasia and the western Arctic Ocean, while westerlies have weakened over northern Canada. Combined with the corresponding pattern in meridional winds, these results suggest that the polar vortex has, on average, shifted toward northern Canada. Seasonal trends show that some changes persist throughout the year while others vary in magnitude and sign. Most striking are spring patterns, which differ markedly from the other seasons. Changes in meridional winds are consistent with observed trends in melt-onset date and sea ice concentration in the marginal seas. Anomalies in zonal wind profiles exhibit decadal-scale cyclicity in the eastern Arctic Ocean, while overall shifts in anomaly signs are evident and vary by region. The winter North Atlantic Oscillation (NAO) index correlates moderately with meridional wind anomalies in the Atlantic sector of the Arctic Ocean: positively (0.48) in the Barents Sea and negatively (−0.59) in the Lincoln Sea. These observed trends and anomalies are expected to translate to changes in advected heat and moisture into the Arctic basin, which are likely linked to trends in sea ice extent, melt onset, cloud properties, and surface temperature.
Cumulus Microphysics and Climate Sensitivity
Authors: Del Genio Anthony D. , Kovari William , Yao Mao-Sung , Jonas Jeffrey
Published: August 2005

Precipitation processes in convective storms are potentially a major regulator of cloud feedback. An unresolved issue is how the partitioning of convective condensate between precipitation-size particles that fall out of updrafts and smaller particles that are detrained to form anvil clouds will change as the climate warms. Tropical Rainfall Measuring Mission (TRMM) observations of tropical oceanic convective storms indicate higher precipitation efficiency at warmer sea surface temperature (SST) but also suggest that cumulus anvil sizes, albedos, and ice water paths become insensitive to warming at high temperatures. International Satellite Cloud Climatology Project (ISCCP) data show that instantaneous cirrus and deep convective cloud fractions are positively correlated and increase with SST except at the highest temperatures, but are sensitive to variations in large-scale vertical velocity. A simple conceptual model based on a Marshall–Palmer drop size distribution, empirical terminal velocity–particle size relationships, and assumed cumulus updraft speeds reproduces the observed tendency for detrained condensate to approach a limiting value at high SST. These results suggest that the climatic behavior of observed tropical convective clouds is intermediate between the extremes required to support the thermostat and adaptive iris hypotheses.
Statistical Analyses of Satellite Cloud Object Data from CERES. Part I: Methodology and Preliminary Results of the 1998 El Niño/2000 La Niña
Authors: Xu Kuan-Man , Wong Takmeng , Wielicki Bruce A. , Parker Lindsay , Eitzen Zachary A.
Published: August 2005

This study presents an objective classification methodology that uses Earth Observing System (EOS) satellite data to classify distinct “cloud objects” defined by cloud-system types, sizes, geographic locations, and matched large-scale environments. This analysis method identifies a cloud object as a contiguous region of the earth with a single dominant cloud-system type. It determines the shape and size of the cloud object from the satellite data and the cloud-system selection criteria. The statistical properties of the identified cloud objects are analyzed in terms of probability density functions (PDFs) based upon the Clouds and the Earth’s Radiant Energy System (CERES) Single Satellite Footprint (SSF) data.

Four distinct types of oceanic cloud objects—tropical deep convection, boundary layer cumulus, transition stratocumulus, and solid stratus—are initially identified from the CERES data collected from the Tropical Rainfall Measuring Mission (TRMM) satellite for this study. Preliminary results are presented from the analysis of the grand-mean PDFs of these four distinct types of cloud objects associated with the strong 1997/98 El Niño in March 1998 and the very weak 2000 La Niña in March 2000. A majority of the CERES footprint statistical characteristics of observed tropical deep convection are similar between the two periods in spite of the climatological contrast. There are, however, statistically significant differences in some cloud macrophysical properties such as the cloud-top height and cloud-top pressure and moderately significant differences in outgoing longwave radiation (OLR), cloud-top temperature, and ice diameter. The footprint statistical characteristics of the three observed boundary layer cloud-system types are distinctly different from one another in all cloud microphysical, macrophysical, optical properties, and radiative fluxes. The differences between the two periods are not significant for most cloud microphysical and optical properties and the top-of-the-atmosphere albedo, but are statistically significant for some cloud macrophysical properties and OLR. These characteristics of the grand-mean PDFs of cloud microphysical, macrophysical, and optical properties and radiative fluxes can be usefully compared with cloud model simulations.

Furthermore, the proportion of different boundary layer cloud types is changed between the two periods in spite of small differences in their grand-mean statistical properties. An increase of the stratus population and a decrease of the cumulus population are evident in the El Niño period compared to the very weak La Niña period. The number of the largest tropical convective cloud objects is larger during the El Niño period, but the total number of tropical convective cloud objects is approximately the same in the two periods.