NobleBlocks
Thales (Portugal) logo

Thales (Portugal)

companyPaço de Arcos, Portugal

Research output, citation impact, and the most-cited recent papers from Thales (Portugal) (Portugal). Aggregated across the NobleBlocks index of 300M+ scholarly works.

Total works
1.7K
Citations
59.7K
h-index
77
i10-index
1.4K
Also known as
Thales (Portugal)

Top-cited papers from Thales (Portugal)

Spontaneous Coronary Artery Dissection: Current State of the Science: A Scientific Statement From the American Heart Association
Sharonne N. Hayes, Esther Kim, Jacqueline Saw, David Adlam +4 more
2018· Circulation1.2Kdoi:10.1161/cir.0000000000000564

Spontaneous coronary artery dissection (SCAD) has emerged as an important cause of acute coronary syndrome, myocardial infarction, and sudden death, particularly among young women and individuals with few conventional atherosclerotic risk factors. Patient-initiated research has spurred increased awareness of SCAD, and improved diagnostic capabilities and findings from large case series have led to changes in approaches to initial and long-term management and increasing evidence that SCAD not only is more common than previously believed but also must be evaluated and treated differently from atherosclerotic myocardial infarction. High rates of recurrent SCAD; its association with female sex, pregnancy, and physical and emotional stress triggers; and concurrent systemic arteriopathies, particularly fibromuscular dysplasia, highlight the differences in clinical characteristics of SCAD compared with atherosclerotic disease. Recent insights into the causes of, clinical course of, treatment options for, outcomes of, and associated conditions of SCAD and the many persistent knowledge gaps are presented.

Autoradiographic investigation of cell proliferation in the brains of rats and cats
Joseph Altman
1963· The Anatomical Record612doi:10.1002/ar.1091450409

Abstract Cell proliferation in the brains of rats and cats was investigated autoradiographically. Two young adult rats were injected intraperitoneally with 2 mc of thymidine‐H 3 and killed after a two weeks' exchange period. Two adult cats were injected intraventricularly with 0.5 mc of thymidine‐H 3 and killed one week later. Labeling of cell nuclei in the brain, presumed to reflect DNA turnover and cellular proliferation, was investigated. In the rats, some neuroglia cells were found labeled in all parts of the brain, suggesting a low rate of glial proliferation. In addition, circumscribed small regions with numerous labeled neuroglia and microglia cells were seen in several brain regions, suggesting the occurrence of local glial proliferative reactions in these presumably normal brains. A few apparently labeled neurons were seen in the neocortex, and a proliferative region of granule cells was identified in the dentate gyrus of the hippocampus. In the cats labeling of glia cells was highest in the midline region, near the point of injection of the radiochemical, with a gradient of decreasing number of labeled cells both laterally and in the anteroposterior direction of the neuraxis. Neurons with apparently labeled nuclei were observed in the midline cortex bilaterally in both animals. These results indicate that glia cells can multiply in the brains of young adult rats and adult cats and they support the possibility that new neurons may be formed in forebrain structures, both in rodents and carnivores.

Lazy Prices
Lauren Cohen, Christopher J. Malloy, Quoc Hung Nguyen
2020· The Journal of Finance357doi:10.1111/jofi.12885

ABSTRACT Using the complete history of regular quarterly and annual filings by U.S. corporations, we show that changes to the language and construction of financial reports have strong implications for firms’ future returns and operations. A portfolio that shorts “changers” and buys “nonchangers” earns up to 188 basis points per month in alpha (over 22% per year) in the future. Moreover, changes to 10‐Ks predict future earnings, profitability, future news announcements, and even future firm‐level bankruptcies. Unlike typical underreaction patterns, we find no announcement effect, suggesting that investors are inattentive to these simple changes across the universe of public firms.

WILDCAT: Weakly Supervised Learning of Deep ConvNets for Image Classification, Pointwise Localization and Segmentation
Thibaut Durand, Taylor Mordan, Nicolas Thome, Matthieu Cord
2017353doi:10.1109/cvpr.2017.631

This paper introduces WILDCAT, a deep learning method which jointly aims at aligning image regions for gaining spatial invariance and learning strongly localized features. Our model is trained using only global image labels and is devoted to three main visual recognition tasks: image classification, weakly supervised object localization and semantic segmentation. WILDCAT extends state-of-the-art Convolutional Neural Networks at three main levels: the use of Fully Convolutional Networks for maintaining spatial resolution, the explicit design in the network of local features related to different class modalities, and a new way to pool these features to provide a global image prediction required for weakly supervised training. Extensive experiments show that our model significantly outperforms state-of-the-art methods.

Transparency and Liquidity: A Study of Block Trades on the London Stock Exchange under Different Publication Rules
GORDON GEMMILL
1996· The Journal of Finance224doi:10.1111/j.1540-6261.1996.tb05225.x

ABSTRACT This article examines whether reducing a market's transparency, by delaying the publication of prices for block trades, has any impact on liquidity. The analysis uses a sample of 5987 blocks from the London Stock Exchange that cover three different publication regimes: immediate (1987/88), 90 minutes (1991/92), and 24 hours (1989/90). Delaying publication does not affect the time taken by prices to reach a new level, which is rapid under all regimes. Spreads differ across years, but their size relates more closely to market volatility than to speed of publication. There is therefore no gain in liquidity from delayed publication.

Cervical Arterial Dissections and Association With Cervical Manipulative Therapy
José Biller, Ralph L. Sacco, Felipe C Albuquerque, Bart M. Demaerschalk +4 more
2014· Stroke218doi:10.1161/str.0000000000000016

PURPOSE: Cervical artery dissections (CDs) are among the most common causes of stroke in young and middle-aged adults. The aim of this scientific statement is to review the current state of evidence on the diagnosis and management of CDs and their statistical association with cervical manipulative therapy (CMT). In some forms of CMT, a high or low amplitude thrust is applied to the cervical spine by a healthcare professional. METHODS: Members of the writing group were appointed by the American Heart Association Stroke Council's Scientific Statements Oversight Committee and the American Heart Association's Manuscript Oversight Committee. Members were assigned topics relevant to their areas of expertise and reviewed appropriate literature, references to published clinical and epidemiology studies, morbidity and mortality reports, clinical and public health guidelines, authoritative statements, personal files, and expert opinion to summarize existing evidence and to indicate gaps in current knowledge. RESULTS: Patients with CD may present with unilateral headaches, posterior cervical pain, or cerebral or retinal ischemia (transient ischemic or strokes) attributable mainly to artery-artery embolism, CD cranial nerve palsies, oculosympathetic palsy, or pulsatile tinnitus. Diagnosis of CD depends on a thorough history, physical examination, and targeted ancillary investigations. Although the role of trivial trauma is debatable, mechanical forces can lead to intimal injuries of the vertebral arteries and internal carotid arteries and result in CD. Disability levels vary among CD patients with many having good outcomes, but serious neurological sequelae can occur. No evidence-based guidelines are currently available to endorse best management strategies for CDs. Antiplatelet and anticoagulant treatments are both used for prevention of local thrombus and secondary embolism. Case-control and other articles have suggested an epidemiologic association between CD, particularly vertebral artery dissection, and CMT. It is unclear whether this is due to lack of recognition of preexisting CD in these patients or due to trauma caused by CMT. Ultrasonography, computed tomographic angiography, and magnetic resonance imaging with magnetic resonance angiography are useful in the diagnosis of CD. Follow-up neuroimaging is preferentially done with noninvasive modalities, but we suggest that no single test should be seen as the gold standard. CONCLUSIONS: CD is an important cause of ischemic stroke in young and middle-aged patients. CD is most prevalent in the upper cervical spine and can involve the internal carotid artery or vertebral artery. Although current biomechanical evidence is insufficient to establish the claim that CMT causes CD, clinical reports suggest that mechanical forces play a role in a considerable number of CDs and most population controlled studies have found an association between CMT and VAD stroke in young patients. Although the incidence of CMT-associated CD in patients who have previously received CMT is not well established, and probably low, practitioners should strongly consider the possibility of CD as a presenting symptom, and patients should be informed of the statistical association between CD and CMT prior to undergoing manipulation of the cervical spine.

High-energy hybrid femtosecond laser system demonstrating 2 × 10 PW capability
François Lureau, Guillaume Matras, Olivier Chalus, C. Derycke +4 more
2020· High Power Laser Science and Engineering201doi:10.1017/hpl.2020.41

Abstract We report on a two-arm hybrid high-power laser system (HPLS) able to deliver 2 × 10 PW femtosecond pulses, developed at the Bucharest-Magurele Extreme Light Infrastructure Nuclear Physics (ELI-NP) Facility. A hybrid front-end (FE) based on a Ti:sapphire chirped pulse amplifier and a picosecond optical parametric chirped pulse amplifier based on beta barium borate (BBO) crystals, with a cross-polarized wave (XPW) filter in between, has been developed. It delivers 10 mJ laser pulses, at 10 Hz repetition rate, with more than 70 nm spectral bandwidth and high-intensity contrast, in the range of 10 13 :1. The high-energy Ti:sapphire amplifier stages of both arms were seeded from this common FE. The final high-energy amplifier, equipped with a 200 mm diameter Ti:sapphire crystal, has been pumped by six 100 J nanosecond frequency doubled Nd:glass lasers, at 1 pulse/min repetition rate. More than 300 J output pulse energy has been obtained by pumping with only 80% of the whole 600 J available pump energy. The compressor has a transmission efficiency of 74% and an output pulse duration of 22.7 fs was measured, thus demonstrating that the dual-arm HPLS has the capacity to generate 10 PW peak power femtosecond pulses. The reported results represent the cornerstone of the ELI-NP 2 × 10 PW femtosecond laser facility, devoted to fundamental and applied nuclear physics research.

Fault-Tolerant Operation of an Open-End Winding Five-Phase PMSM Drive With Short-Circuit Inverter Fault
Ngac Ky Nguyen, Fabien Meinguet, Eric Semail, Xavier Kestelyn
2015· IEEE Transactions on Industrial Electronics184doi:10.1109/tie.2014.2386299

Multiphase machines are well known for their fault-tolerant capability. Star-connected multiphase machines have fault tolerance in an open circuit. For an inverter switch short-circuit fault, it is possible to keep a smooth torque of a permanent magnet synchronous machine if the currents of the faulty phases are determined and their values are acceptable. This paper investigates fault-tolerant operations of an open-end five-phase drive, i.e., a multiphase machine fed with a dual-inverter supply. Inverter switch short-circuit fault is considered and handled with a simple solution. Original theoretical developments are presented. Simulation and experimental results validate the proposed strategy.

Risk Factors for Abdominal Donor-Site Morbidity in Free Flap Breast Reconstruction
Raj M. Vyas, Brian P. Dickinson, Jaco H. Fastekjian, J. P. Watson +2 more
2008· Plastic & Reconstructive Surgery182doi:10.1097/prs.0b013e31816b1458

BACKGROUND: The lower abdomen is the most popular donor site for autologous tissue breast reconstruction. Several studies have reported abdominal morbidity following pedicled and free flap reconstructions using this donor site, yet few studies have compared the various types of free flaps and investigated specific operative and patient-related factors that are associated with higher rates of abdominal complications. METHODS: The authors conducted a retrospective review of all free flap breast reconstructions performed at University of California Los Angeles Medical Center between July of 2002 and July of 2005. RESULTS: A total of 279 patients underwent 211 unilateral and 68 bilateral reconstructions, totaling 347 flaps. Eleven percent were free transverse rectus abdominis myocutaneous (TRAM) flaps, 52 percent were muscle-sparing free TRAM flaps, and 37 percent were deep inferior epigastric perforator (DIEP) flaps. Mean follow-up was 29.9 months. There were 30 total abdominal complications (10.9 percent of patients), including 17 rectus bulges and five hernias. Free TRAM reconstructions had a significantly higher rate of donor-site complications than did DIEP reconstructions. Bilateral flap harvests and obesity (body mass index >30) were significant risk factors for (1) any donor-site complication and (2) rectus bulge/hernia formation. There was no significant increase in donor-site complications associated with various prior abdominal operations. CONCLUSIONS: Donor-site complications are not uncommon, but paying careful attention to patient comorbidities when selecting an operative approach (bilateral versus unilateral, free TRAM versus DIEP, and so on) can minimize postoperative abdominal complications. Furthermore, the results corroborate the recent literature suggesting there is little functional difference in patients receiving muscle-sparing free TRAM versus DIEP reconstructions.

Transparency and Liquidity: A Study of Block Trades on the London Stock Exchange under Different Publication Rules
Gordon Gemmill
1996· The Journal of Finance180doi:10.2307/2329537

This article examines whether reducing a market's transparency, by delaying the publication of prices for block trades, has any impact on liquidity. The analysis uses a sample of 5987 blocks from the London Stock Exchange that cover three different publication regimes: immediate (1987/88), 90 minutes (1991/92), and 24 hours (1989/90). Delaying publication does not affect the time taken by prices to reach a new level, which is rapid under all regimes. Spreads differ across years, but their size relates more closely to market volatility than to speed of publication. There is therefore no gain in liquidity from delayed publication.

High-Resolution Direction Finding From Higher Order Statistics: The$2rm q$-MUSIC Algorithm
Pascal Chevalier, Anne Ferréol, Laurent Albera
2006· IEEE Transactions on Signal Processing163doi:10.1109/tsp.2006.877661

From the beginning of the 1980s, many second-order (SO) high-resolution direction-finding methods, such as the MUSIC method (or 2-MUSIC), have been developed mainly to process efficiently the multisource environments. Despite of their great interests, these methods suffer from serious drawbacks such as a weak robustness to both modeling errors and the presence of a strong colored background noise whose spatial coherence is unknown, poor performance in the presence of several poorly angularly separated sources from a limited duration observation and a maximum of N-1 sources to be processed from an array of N sensors. Mainly to overcome these limitations and in particular to increase both the resolution and the number of sources to be processed from an array of N sensors, fourth-order (FO) high-resolution direction-finding methods have been developed, from the end of the 1980s, to process non-Gaussian sources, omnipresent in radio communications, among which the 4-MUSIC method is the most popular. To increase even more the resolution, the robustness to modeling errors, and the number of sources to be processed from a given array of sensors, and thus to minimize the number of sensors in operational contexts, we propose in this paper an extension of the MUSIC method to an arbitrary even order 2q (qges1), giving rise to the 2q-MUSIC methods. The performance analysis of these new methods show off new important results for direction-finding applications and in particular the best performances, with respect to 2-MUSIC and 4-MUSIC, of 2q-MUSIC methods with q>2, despite their higher variance, when some resolution is required

Displacement Spectra for Long Periods
Ezio Faccioli, Roberto Paolucci, Julien Rey
2004· Earthquake Spectra153doi:10.1193/1.1707022

Using selected sets of high‐quality digital strong motion data from different regions (Taiwan, Japan, Italy, and Greece), the salient features of displacement response spectra in the long‐period range are illustrated (up to 10 s period) as a function of magnitude, source distance, and site conditions. By means of simple analytical models of displacement waveforms, we have derived analytical expressions for the displacement spectra that provide satisfactory fits to the observations. These expressions also demonstrate that the moment magnitude and distance control the shape of the spectra consistent with the commonly accepted models of the seismic source. Furthermore, we derived from simple physical considerations an analytical expression of the variation of peak ground displacement with magnitude and distance that reasonably fits the observations. The findings of this study are believed to be particularly useful in the formulation of design elastic displacement spectra for seismic codes, and in zoning studies of seismic hazard for long‐period structures.

A Genome-Wide Association Study Identifies <i>LIPA</i> as a Susceptibility Gene for Coronary Artery Disease
Philipp S. Wild, Tanja Zeller, Arne Schillert, Silke Szymczak +4 more
2011· Circulation Cardiovascular Genetics152doi:10.1161/circgenetics.110.958728

BACKGROUND: eQTL analyses are important to improve the understanding of genetic association results. We performed a genome-wide association and global gene expression study to identify functionally relevant variants affecting the risk of coronary artery disease (CAD). METHODS AND RESULTS: In a genome-wide association analysis of 2078 CAD cases and 2953 control subjects, we identified 950 single-nucleotide polymorphisms (SNPs) that were associated with CAD at P<10(-3). Subsequent in silico and wet-laboratory replication stages and a final meta-analysis of 21 428 CAD cases and 38 361 control subjects revealed a novel association signal at chromosome 10q23.31 within the LIPA (lysosomal acid lipase A) gene (P=3.7×10(-8); odds ratio, 1.1; 95% confidence interval, 1.07 to 1.14). The association of this locus with global gene expression was assessed by genome-wide expression analyses in the monocyte transcriptome of 1494 individuals. The results showed a strong association of this locus with expression of the LIPA transcript (P=1.3×10(-96)). An assessment of LIPA SNPs and transcript with cardiovascular phenotypes revealed an association of LIPA transcript levels with impaired endothelial function (P=4.4×10(-3)). CONCLUSIONS: The use of data on genetic variants and the addition of data on global monocytic gene expression led to the identification of the novel functional CAD susceptibility locus LIPA, located on chromosome 10q23.31. The respective eSNPs associated with CAD strongly affect LIPA gene expression level, which was related to endothelial dysfunction, a precursor of CAD.

10 PW peak power femtosecond laser pulses at ELI-NP
Christophe Radier, Olivier Chalus, Mathilde Charbonneau, Shanjuhan Thambirajah +4 more
2022· High Power Laser Science and Engineering141doi:10.1017/hpl.2022.11

Abstract We report on the generation and delivery of 10.2 PW peak power laser pulses, using the High Power Laser System at the Extreme Laser Infrastructure – Nuclear Physics facility. In this work we demonstrate for the first time, to the best of our knowledge, the compression and propagation of full energy, full aperture, laser pulses that reach a power level of more than 10 PW.

Generative Models from the perspective of Continual Learning
Garcia Ortiz, M., Lesort, T., Caselles-Dupré, H., Goudou, J-F. +1 more
2019· City Research Online (City University London)132doi:10.1109/ijcnn.2019.8851986

Which generative model is the most suitablefor Continual Learning? This paper aims at evaluating andcomparing generative models on disjoint sequential imagegeneration tasks. We investigate how several models learn andforget, considering various strategies: rehearsal, regularization,generative replay and fine-tuning. We used two quantitativemetrics to estimate the generation quality and memory ability.We experiment with sequential tasks on three commonly usedbenchmarks for Continual Learning (MNIST, Fashion MNISTand CIFAR10). We found that among all models, the originalGAN performs best and among Continual Learning strategies,generative replay outperforms all other methods. Even ifwe found satisfactory combinations on MNIST and FashionMNIST, training generative models sequentially on CIFAR10is particularly instable, and remains a challenge. Our code isavailable online.

Widely Linear MVDR Beamformers for the Reception of an Unknown Signal Corrupted by Noncircular Interferences
Pascal Chevalier, Audrey Blin
2007· IEEE Transactions on Signal Processing129doi:10.1109/tsp.2007.899394

For nonstationary observations, potentially second-order (SO) noncircular, the SO optimal complex filters are time variant (TV) and, under some conditions of noncircularity, widely linear (WL). Moreover, for applications such as spectrum monitoring or passive listening, the sources' waveforms are unknown and no training sequence or spreading code is a priori available. In this context, this paper aims at introducing the time invariant (TI) WL minimum variance distortionless response (MVDR) beamformer for the optimal reception of an unknown signal, whose waveform is unknown but whose steering vector is known, corrupted by potentially noncircular interferences. Its properties, performance, and adaptive implementation in noncircular contexts are analyzed in this paper. This optimal beamformer is shown to always improve, in the steady state, the performance of the well-known Capon's beamformer for noncircular interferences. Moreover, it should be noticed that this optimal beamformer allows the processing of up to 2 (N-1) rectilinear interferences from an array of N sensors. Finally, at the end of this paper, a TV extension of this TI WL MVDR beamformer is presented to process SO noncircular interferences having a nonnull carrier residue or frequency offset.

In Plain Sight: The Neglected Linkage between Brideprice and Violent Conflict
Valerie M. Hudson, Hilary Matfess
2017· International Security118doi:10.1162/isec_a_00289

Abstract Approximately seventy-five percent of the world's population lives in countries where asset exchange upon marriage is obligatory. Rising brideprice—money or gifts provided to a woman's family by the groom and his family as part of marriage arrangements—is a common if overlooked catalyst of violent conflict. In patrilineal (and some matrilineal) societies where brideprice is practiced, a man's social status is directly connected to his marital status. Brideprice acts as a flat tax that is prone to sudden and swift increases. As a result, rising brideprice can create serious marriage market distortions that prevent young men, especially those who are poor or otherwise marginalized, from marrying. This phenomenon is especially evident in polygamous societies, where wealthy men can afford more than one bride. These distortions incentivize extra-legal asset accumulation, whether through ad hoc raiding or organized violence. In such situations, rebel and terror groups may offer to pay brideprice—or even provide brides—to recruit new members. Descriptive case studies of Boko Haram in Nigeria and various armed groups in South Sudan demonstrate these linkages, while an examination of Saudi Arabia's cap on brideprice and its efforts to arrange low-cost mass weddings illustrates the ways in which governments can intervene in marriage markets to help prevent brideprice-related instability. The trajectory of brideprice is an important but neglected early indicator of societal instability and violent conflict, underscoring that the situation and security of women tangibly affect national security.

Fully FPGA-Based Sensorless Control for Synchronous AC Drive Using an Extended Kalman Filter
Lahoucine Idkhajine, Éric Monmasson, A. Maalouf
2012· IEEE Transactions on Industrial Electronics118doi:10.1109/tie.2012.2189533

The aim of this paper is to quantify the interest of using hardware field-programmable gate arrays (FPGAs) to implement complex control algorithms. As a benchmark, authors have chosen a sensorless speed controller for a synchronous motor. The estimation of the rotor position and speed is achieved using an extended Kalman filter (EKF), eliminating the need of their corresponding mechanical sensors. Due to the EKF complexity, such sensorless controller is systematically implemented in a software digital signal processor (DSP) device. The execution time is frequently evaluated to several tens or hundreds of microseconds. The motivation here is to prove that, when exploiting the treatment fastness of FPGAs (less than 6 μs ), it is possible to enhance the control bandwidth. To reach this objective, a comparison between the developed FPGA-based sensorless speed controller and its DSP-based counterpart is made. The same sensorless controller (with the same complexity) has been implemented in both cases. To prop up this comparison, simulation, hardware-in-the-loop, and experimental tests are presented.

Association Between Chromosome 9p21 Variants and the Ankle-Brachial Index Identified by a Meta-Analysis of 21 Genome-Wide Association Studies
Joanne M. Murabito, Charles C. White, Maryam Kavousi, Yan V. Sun +4 more
2011· Circulation Cardiovascular Genetics115doi:10.1161/circgenetics.111.961292

BACKGROUND: Genetic determinants of peripheral arterial disease (PAD) remain largely unknown. To identify genetic variants associated with the ankle-brachial index (ABI), a noninvasive measure of PAD, we conducted a meta-analysis of genome-wide association study data from 21 population-based cohorts. METHODS AND RESULTS: Continuous ABI and PAD (ABI ≤0.9) phenotypes adjusted for age and sex were examined. Each study conducted genotyping and imputed data to the ≈2.5 million single nucleotide polymorphisms (SNPs) in HapMap. Linear and logistic regression models were used to test each SNP for association with ABI and PAD using additive genetic models. Study-specific data were combined using fixed effects inverse variance weighted meta-analyses. There were a total of 41 692 participants of European ancestry (≈60% women, mean ABI 1.02 to 1.19), including 3409 participants with PAD and with genome-wide association study data available. In the discovery meta-analysis, rs10757269 on chromosome 9 near CDKN2B had the strongest association with ABI (β=-0.006, P=2.46×10(-8)). We sought replication of the 6 strongest SNP associations in 5 population-based studies and 3 clinical samples (n=16 717). The association for rs10757269 strengthened in the combined discovery and replication analysis (P=2.65×10(-9)). No other SNP associations for ABI or PAD achieved genome-wide significance. However, 2 previously reported candidate genes for PAD and 1 SNP associated with coronary artery disease were associated with ABI: DAB21P (rs13290547, P=3.6×10(-5)), CYBA (rs3794624, P=6.3×10(-5)), and rs1122608 (LDLR, P=0.0026). CONCLUSIONS: Genome-wide association studies in more than 40 000 individuals identified 1 genome wide significant association on chromosome 9p21 with ABI. Two candidate genes for PAD and 1 SNP for coronary artery disease are associated with ABI.

Patterns of Pediatric Supracondylar Humerus Fractures
Michael S. Bahk, Uma Srikumaran, Michael C. Ain, Gürkan Erkula +3 more
2008· Journal of Pediatric Orthopaedics112doi:10.1097/bpo.0b013e31817bb860

PURPOSE: The Wilkins-modified Gartland classification of pediatric supracondylar humerus fractures does not consider coronal or sagittal obliquity. The purposes of our study were (1) to identify and describe fracture characteristics with unique properties and (2) to propose a fracture classification system that can be reproduced reliably. METHODS: We retrospectively studied 203 consecutive displaced pediatric extension-type supracondylar humerus fractures treated operatively from January 1998 to January 2003. Fracture characteristics (eg, coronal and sagittal obliquity, postoperative alignment), type of surgical treatment, outcome, and complications were assessed and analyzed statistically with Student t test and a receiver operating characteristic curve. Significance was defined as P < 0.05. We incorporated significant cutoff values for fracture obliquity into our classification scheme and tested the classification's interobserver and intraobserver reliability. RESULTS: We identified 4 coronal (typical transverse, medial oblique, lateral oblique, and high fractures) and 2 sagittal (low sagittal and high sagittal) subtypes with significantly different characteristics and outcome. Compared with fractures with coronal obliquity of less than 10 degrees, fractures with coronal obliquity of 10 degrees or greater were associated with significantly more comminution and rotational malunion. Compared with fractures with sagittal obliquity of less than 20 degrees, fractures with sagittal obliquity of 20 degrees or greater were associated with a significantly higher incidence of additional injuries and were more likely to result in extension malunion. Analysis of the interobserver and intraobserver reliability for our system identified correlation coefficients ranging from 0.772 to 0.907 and 0.860 to 0.899, respectively. CONCLUSIONS: Because pediatric extension-type supracondylar humerus fractures vary significantly in terms of characteristics, identification of sagittal oblique and coronal oblique angles may have an important role in surgical decision making and may impact outcomes.