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2013

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Full-Text Articles in Physical Sciences and Mathematics

High-Resolution Near-Infrared Spectroscopy Of Hd 100546. I. Analysis Of Asymmetric Ro-Vibrational Oh Emission Lines, Joseph Liskowsky, Sean D. Brittain, Joan R. Najita, John S. Carr, Greg W. Doppman, Matthew R. Troutman Nov 2013

High-Resolution Near-Infrared Spectroscopy Of Hd 100546. I. Analysis Of Asymmetric Ro-Vibrational Oh Emission Lines, Joseph Liskowsky, Sean D. Brittain, Joan R. Najita, John S. Carr, Greg W. Doppman, Matthew R. Troutman

Publications

We present observations of ro-vibrational OH and CO emission from the Herbig Be star HD 100546. The emission from both molecules arises from the inner region of the disk extending from approximately 13 AU from the central star. The velocity profiles of the OH lines are narrower than the velocity profile of the [O i] λ6300 line, indicating that the OH in the disk is not cospatial with the Oi. This suggests that the inner optically thin region of the disk is largely devoid of molecular gas. Unlike the ro-vibrational CO emission lines, the OH lines are highly asymmetric. We …


The Update, November 2013, University Of Northern Iowa. College Of Humanities, Arts And Sciences. Nov 2013

The Update, November 2013, University Of Northern Iowa. College Of Humanities, Arts And Sciences.

Update

Inside this issue:

-- Meet the Artists - GBPAC Collaboration: Kristallnacht, Night of Broken Glass
-- Department News
-- TEECA
-- Stephen Gaies
-- Sex and Death in Eighteenth Century Literature
-- School of Music Events
-- Featured Organization: Actuarial Science Club
-- Featured Organization: SAACS
-- Alumni Spotlight: Earth Science: Scott Beason
-- Electronic Media Alumni Achievements
-- New 3D Printer for Metal Casting Center
-- Student Spotlight: Language & Literatures: Sam Bass
-- In Memoriam: Clifton Chancey


A Simple Inexpensive Method For The Rapid Testing Of The Photocatalytic Activity Of Self Cleaning Surfaces, Andrew Mills, James Hepburn, David Hazafy, Christopher O'Rourke, Josef Krysa, Michal Baudys, Martin Zlamal, Hana Bartkova, Claire Hill, Kim Winn, Morten Simonsen, Erik Sogaard, Suresh Pillai, Nigel Leyland, Rachel Fagan, Frank Neumann, Christina Lampe, Tobias Graumann Nov 2013

A Simple Inexpensive Method For The Rapid Testing Of The Photocatalytic Activity Of Self Cleaning Surfaces, Andrew Mills, James Hepburn, David Hazafy, Christopher O'Rourke, Josef Krysa, Michal Baudys, Martin Zlamal, Hana Bartkova, Claire Hill, Kim Winn, Morten Simonsen, Erik Sogaard, Suresh Pillai, Nigel Leyland, Rachel Fagan, Frank Neumann, Christina Lampe, Tobias Graumann

Articles

A rapid semi-quantitative, inexpensive method,using a simple digital scanner and an indicator ink, suitable for use in the laboratory, or in the field, for assessing the photocatalytic activity of commerical photocatalytic self-cleaning materials such as glass, is described. The repeatability of the current method is found to be hight and better than many of the previously reported ISO photocatalyst tests.


Detecting Stable Communities In Large Scale Networks, Sriram Srinivasan Nov 2013

Detecting Stable Communities In Large Scale Networks, Sriram Srinivasan

Student Work

A network is said to exhibit community structure if the nodes of the network can be easily grouped into groups of nodes, such that each group is densely connected internally but sparsely connected with other groups. Most real world networks exhibit community structure.

A popular technique for detecting communities is based on computing the modularity of the network. Modularity reflects how well the vertices in a group are connected as opposed to being randomly connected. We propose a parallel algorithm for detecting modularity in large networks.

However, all modularity based algorithms for detecting community structure are affected by the order …


Observed Versus Gcm-Generated Local Tropical Cyclone Frequency: Comparisons Using A Spatial Lattice, Sarah Strazzo, Daniel J. Halperin, James Elsner, Tim Larow, Ming Zhao Nov 2013

Observed Versus Gcm-Generated Local Tropical Cyclone Frequency: Comparisons Using A Spatial Lattice, Sarah Strazzo, Daniel J. Halperin, James Elsner, Tim Larow, Ming Zhao

Publications

Of broad scientific and public interest is the reliability of global climate models (GCMs) to simulate future regional and local tropical cyclone (TC) occurrences. Atmospheric GCMs are now able to generate vortices resembling actual TCs, but questions remain about their fidelity to observed TCs. Here the authors demonstrate a spatial lattice approach for comparing actual with simulated TC occurrences regionally using observed TCs from the International Best Track Archive for Climate Stewardship (IBTrACS) dataset and GCM-generated TCs from the Geophysical Fluid Dynamics Laboratory (GFDL) High Resolution Atmospheric Model (HiRAM) and Florida State University (FSU) Center for Ocean–Atmospheric Prediction Studies (COAPS) …


Moving Difference (Mdiff) Non-Adiabatic Rapid Sweep (Nars) Epr Of Copper(Ii), James S. Hyde, Brian Bennett, Aaron W. Kittell, Jason M. Kowalski, Jason Walter Sidabras Nov 2013

Moving Difference (Mdiff) Non-Adiabatic Rapid Sweep (Nars) Epr Of Copper(Ii), James S. Hyde, Brian Bennett, Aaron W. Kittell, Jason M. Kowalski, Jason Walter Sidabras

Physics Faculty Research and Publications

Non-adiabatic rapid sweep (NARS) EPR spectroscopy has been introduced for application to nitroxide-labeled biological samples (Kittell et al., 2011). Displays are pure absorption, and are built up by acquiring data in spectral segments that are concatenated. In this paper we extend the method to frozen solutions of copper-imidazole, a square planar copper complex with four in-plane nitrogen ligands. Pure absorption spectra are created from concatenation of 170 5-gauss segments spanning 850 G at 1.9 GHz. These spectra, however, are not directly useful since nitrogen superhyperfine couplings are barely visible. Application of the moving difference (MDIFF) algorithm to the digitized NARS …


Symmetry Robust Descriptor For Non-Rigid Surface Matching, Zhiyuan Zhang, Kangkang Yin, Kelvin W. C. Foong Nov 2013

Symmetry Robust Descriptor For Non-Rigid Surface Matching, Zhiyuan Zhang, Kangkang Yin, Kelvin W. C. Foong

Research Collection School Of Computing and Information Systems

In this paper, we propose a novel shape descriptor that is robust in differentiating intrinsic symmetric points on geometric surfaces. Our motivation is that even the state-of-theart shape descriptors and non-rigid surface matching algorithms suffer from symmetry flips. They cannot differentiate surface points that are symmetric or near symmetric. Hence a left hand of one human model may be matched to a right hand of another. Our Symmetry Robust Descriptor (SRD) is based on a signed angle field, which can be calculated from the gradient fields of the harmonic fields of two point pairs. Experiments show that the proposed shape …


A Scalable Approach For Malware Detection Through Bounded Feature Space Behavior Modeling, Mahinthan Chandramohan, Hee Beng Kuan Tan, Lionel C Briand, Lwin Khin Shar, Bindu Madhavi Padmanabhuni Nov 2013

A Scalable Approach For Malware Detection Through Bounded Feature Space Behavior Modeling, Mahinthan Chandramohan, Hee Beng Kuan Tan, Lionel C Briand, Lwin Khin Shar, Bindu Madhavi Padmanabhuni

Research Collection School Of Computing and Information Systems

In recent years, malware (malicious software) has greatly evolved and has become very sophisticated. The evolution of malware makes it difficult to detect using traditional signature-based malware detectors. Thus, researchers have proposed various behavior-based malware detection techniques to mitigate this problem. However, there are still serious shortcomings, related to scalability and computational complexity, in existing malware behavior modeling techniques. This raises questions about the practical applicability of these techniques. This paper proposes and evaluates a bounded feature space behavior modeling (BOFM) framework for scalable malware detection. BOFM models the interactions between software (which can be malware or benign) and security-critical …


Why Do I Retweet It? An Information Propagation Model For Microblogs, Fabio Pezzoni, Jisun An, Andrea Passarella, Jon Crowcroft, Marco Conti Nov 2013

Why Do I Retweet It? An Information Propagation Model For Microblogs, Fabio Pezzoni, Jisun An, Andrea Passarella, Jon Crowcroft, Marco Conti

Research Collection School Of Computing and Information Systems

Microblogging platforms are Web 2.0 services that represent a suitable environment for studying how information is propagated in social networks and how users can become influential. In this work we analyse the impact of the network features and of the users' behaviour on the information diffusion. Our analysis highlights a strong relation between the level of visibility of a message in the flow of information seen by a user and the probability that the user further disseminates the message. In addition, we also highlight the existence of other latent factors that impact on the dissemination probability, correlated with the properties …


Automatically Partition Software Into Least Privilege Components Using Dynamic Data Dependency Analysis, Yongzheng Wu, Jun Sun, Yang Liu, Jin Song Dong Nov 2013

Automatically Partition Software Into Least Privilege Components Using Dynamic Data Dependency Analysis, Yongzheng Wu, Jun Sun, Yang Liu, Jin Song Dong

Research Collection School Of Computing and Information Systems

The principle of least privilege requires that software components should be granted only necessary privileges, so that compromising one component does not lead to compromising others. However, writing privilege separated software is difficult and as a result, a large number of software is monolithic, i.e., it runs as a whole without separation. Manually rewriting monolithic software into privilege separated software requires significant effort and can be error prone. We propose ProgramCutter, a novel approach to automatically partitioning monolithic software using dynamic data dependency analysis. ProgramCutter works by constructing a data dependency graph whose nodes are functions and edges are data …


Assessing The Moderating Effect Of Consumer Product Knowledge And Online Shopping Experience On Using Recommedation Agents For Customer Loyalty, Victoria Y. Yoon, R. Eric Hostler, Zhiling Guo, Tor Guimaraes Nov 2013

Assessing The Moderating Effect Of Consumer Product Knowledge And Online Shopping Experience On Using Recommedation Agents For Customer Loyalty, Victoria Y. Yoon, R. Eric Hostler, Zhiling Guo, Tor Guimaraes

Research Collection School Of Computing and Information Systems

Social media technologies have greatly facilitated the creation of many types of user-generated information, e.g., product rating information can be used to generate preference-based recommendation. As a decision support tool, a Recommendation Agent (RA) has been widely adopted by many e-commerce websites. The impact of RAs on online shopping has been extensively examined in the IS literature. However, from Marketing and Social Media perspectives, the widely adopted cognitive–affect–conative–action framework of customer loyalty has not been tested in the presence of RAs. Moreover, there has been little research assessing the impact of increasing consumer knowledge about specific product domains on customer …


Using Micro-Reviews To Select An Efficient Set Of Reviews, Thanh-Son Nguyen, Hady W. Lauw, Panayiotis Tsaparas Nov 2013

Using Micro-Reviews To Select An Efficient Set Of Reviews, Thanh-Son Nguyen, Hady W. Lauw, Panayiotis Tsaparas

Research Collection School Of Computing and Information Systems

Online reviews are an invaluable resource for web users trying to make decisions regarding products or services. However, the abundance of review content, as well as the unstructured, lengthy, and verbose nature of reviews make it hard for users to locate the appropriate reviews, and distill the useful information. With the recent growth of social networking and micro-blogging services, we observe the emergence of a new type of online review content, consisting of bite-sized, 140 character-long reviews often posted reactively on the spot via mobile devices. These micro-reviews are short, concise, and focused, nicely complementing the lengthy, elaborate, and verbose …


Achieving Revocable Fine-Grained Cryptographic Access Control Over Cloud Data, Yanjiang Yang, Xuhua Ding, Haibing Lu, Zhiguo Wan, Jianying Zhou Nov 2013

Achieving Revocable Fine-Grained Cryptographic Access Control Over Cloud Data, Yanjiang Yang, Xuhua Ding, Haibing Lu, Zhiguo Wan, Jianying Zhou

Research Collection School Of Computing and Information Systems

Attribute-based encryption (ABE) is well suited for finegrained access control for data residing on a cloud server. However, existing approaches for user revocation are not satisfactory. In this work, we propose a new approach which works by splitting an authorized user’s decryption capability between the cloud and the user herself. User revocation is attained by simply nullifying the decryption ability at the cloud, requiring neither key update nor re-generation of cloud data. We propose a concrete scheme instantiating the approach, which features lightweight computation at the user side. This makes it possible for users to use resource-constrained devices such as …


Self-Blindable Credential: Towards Anonymous Entity Authentication Upon Resource-Constrained Devices, Yanjiang Yang, Xuhua Ding, Haibing Lu, Jian Weng, Jianying Zhou Nov 2013

Self-Blindable Credential: Towards Anonymous Entity Authentication Upon Resource-Constrained Devices, Yanjiang Yang, Xuhua Ding, Haibing Lu, Jian Weng, Jianying Zhou

Research Collection School Of Computing and Information Systems

We are witnessing the rapid expansion of smart devices in our daily life. The need for individual privacy protection calls for anonymous entity authentication techniques with affordable efficiency upon the resource-constrained smart devices. Towards this objective, in this paper we propose self-blindable credential, a lightweight anonymous entity authentication primitive.We provide a formulation of the primitive and present two concrete instantiations. The first scheme implements verifier-local revocation and the second scheme enhances the former with forward security. Our analytical performance results show that our schemes outperform relevant existing schemes.


Covariance Selection By Thresholding The Sample Correlation Matrix, Binyan Jiang Nov 2013

Covariance Selection By Thresholding The Sample Correlation Matrix, Binyan Jiang

Research Collection School Of Computing and Information Systems

This article shows that when the nonzero coefficients of the population correlation matrix are all greater in absolute value than (C1logp/n)1/2 for some constant C1, we can obtain covariance selection consistency by thresholding the sample correlation matrix. Furthermore, the rate (logp/n)1/2 is shown to be optimal.


Predicting User's Political Party Using Ideological Stances, Swapna Gottopati, Minghui Qiu, Liu Yang, Feida Zhu, Jing Jiang Nov 2013

Predicting User's Political Party Using Ideological Stances, Swapna Gottopati, Minghui Qiu, Liu Yang, Feida Zhu, Jing Jiang

Research Collection School Of Computing and Information Systems

Predicting users political party in social media has important impacts on many real world applications such as targeted advertising, recommendation and personalization. Several political research studies on it indicate that political parties’ ideological beliefs on sociopolitical issues may influence the users political leaning. In our work, we exploit users’ ideological stances on controversial issues to predict political party of online users. We propose a collaborative filtering approach to solve the data sparsity problem of users stances on ideological topics and apply clustering method to group the users with the same party. We evaluated several state-of-the-art methods for party prediction task …


What's In An Algorithm?, George K. Thiruvathukal Nov 2013

What's In An Algorithm?, George K. Thiruvathukal

Computer Science: Faculty Publications and Other Works

How can we rethink the definition of algorithm, and through that, produce another age of enlightenment in modern scientific programming and software development in general? Removing these limitations in our own thoughts is the key for expanding the possibilities in alternative paradigms and exploiting parallel and next-generation hardware.


Nitroxide-Functionalized Graphene Oxide From Graphite Oxide, Yazmin I. Avila-Vega, Cesar C. Leyva-Porras, Marcela Mireles, Manuel Quevedo-Lopez, Javier Macossay-Torres, Jose Bonilla-Cruz Nov 2013

Nitroxide-Functionalized Graphene Oxide From Graphite Oxide, Yazmin I. Avila-Vega, Cesar C. Leyva-Porras, Marcela Mireles, Manuel Quevedo-Lopez, Javier Macossay-Torres, Jose Bonilla-Cruz

Chemistry Faculty Publications and Presentations

A facile method for preparing functionalized graphene oxide single layers with nitroxide groups is reported herein. Highly oxidized graphite oxide (GO=90.6%) was obtained, slightly modifying an improved Hummer’s method. Oxoammonium salts (OS) were investigated to introduce nitroxide groups to GO, resulting in a one-step functionalization and exfoliation. The mechanisms of functionalization/exfoliation are proposed, where the oxidation of aromatic alcohols to ketone groups, and the formation of alkoxyamine species are suggested. Two kinds of functionalized graphene oxide layers (GOFT1 and GOFT2) were obtained by controlling the amount of OS added. GOFT1 and GOFT2 exhibited a high interlayer spacing (d0001 = 1.12nm), …


The Effects Of Large Wildfires On Employment And Wage Growth And Volatility In The Western United States, Max Nielsen-Pincus, Cassandra Moseley, Krista Gebert Nov 2013

The Effects Of Large Wildfires On Employment And Wage Growth And Volatility In The Western United States, Max Nielsen-Pincus, Cassandra Moseley, Krista Gebert

Environmental Science and Management Faculty Publications and Presentations

We examined the effect of large wildfires on economic growth and volatility in the western United States. We matched wildfire data with quarterly employment and earnings growth data to assess the specific effect of wildfire on employment and wage growth in western US counties. Wildfires generally tended to exhibit positive effects on employment and wage growth in the quarter(s) during which suppression efforts were active. However, this effect transitioned to increased economic volatility following a wildfire. The effect of wildfire also varied by the type of county in which wildfire occurred. The amount of suppression costs invested locally had the …


Development Of A Biosensor For Investigating Membrane Curvature Sorting, Joshua C. Black Nov 2013

Development Of A Biosensor For Investigating Membrane Curvature Sorting, Joshua C. Black

Electronic Theses and Dissertations

The physical structure of cellular membranes plays a critical role in lipid and protein sorting. A novel biosensor was developed to probe the influence of curvature on sorting. This biosensor mimics large, two-dimensional membranes in dynamic equilibrium, achieves high spatial resolution between curvature and molecules of interest, and has high sensitivity, enough for single particle detection. The biosensor consists of continuous supported lipid bilayer formed over nanoparticles (40 to 200 nm diameter) deposited on a glass substrate. The nanoparticles determine the extent of curvature. This biosensor is the first to observe large-scale 2-dimensional diffusion of biomolecules on a supported lipid …


Defects And Dark Current In Organic Photovoltaics And Impacts On Device Physics, Xin Jiang Nov 2013

Defects And Dark Current In Organic Photovoltaics And Impacts On Device Physics, Xin Jiang

Electronic Theses and Dissertations

In this dissertation, we discussed the shape, energy level and density of defects in Organic Photovoltaic (OPV) devices by both theoretical and experimental methods. The energy band structure and intrinsic junctions of general standard and inverted OPV devices are investigated in detail. Transportation of separated holes and electrons in both structures are well analyzed. In chapter II, we developed a Monte-Carlo model to simulate charge transport process in organic materials. Marcus theory is applied to calculate the carrier transfer rate to build up hopping process in ideal lattices. Results of this model showed several properties of carriers regarding mobility, reorganization …


Assessing Protein Conformational Sampling Methods Based On Bivariate Lag-Distributions Of Backbone Angles, Mehdi Maadooliat, Xin Gao, Jianhua Z. Huang Nov 2013

Assessing Protein Conformational Sampling Methods Based On Bivariate Lag-Distributions Of Backbone Angles, Mehdi Maadooliat, Xin Gao, Jianhua Z. Huang

Mathematics, Statistics and Computer Science Faculty Research and Publications

Despite considerable progress in the past decades, protein structure prediction remains one of the major unsolved problems in computational biology. Angular-sampling-based methods have been extensively studied recently due to their ability to capture the continuous conformational space of protein structures. The literature has focused on using a variety of parametric models of the sequential dependencies between angle pairs along the protein chains. In this article, we present a thorough review of angular-sampling-based methods by assessing three main questions: What is the best distribution type to model the protein angles? What is a reasonable number of components in a mixture model …


Auroral Ion Upflows: Sources, High Altitude Dynamics, And Neutral Wind Effects, Meghan R. Burleigh Nov 2013

Auroral Ion Upflows: Sources, High Altitude Dynamics, And Neutral Wind Effects, Meghan R. Burleigh

Doctoral Dissertations and Master's Theses

Large upwellings of thermal plasma are commonly observed in the high-latitude, topside ionosphere. These auroral ion upflows have a range of potential sources including frictional heating, electron precipitation, neutral winds, and higher-altitude density cavities. The unique signatures and detailed evolution of these upflows are examined through the use of Incoherent Scatter Radar data and a sophisticated ionospheric fluid model.

A survey of solar cycle 23 shows that at Sondrestrom upflows occur most often in the cusp region and midnight auroral zone. Simplified force balance analysis and steady state velocity calculations are applied to a few select events to elucidate the …


Quotients Of Gaussian Primes, Stephan Ramon Garcia Nov 2013

Quotients Of Gaussian Primes, Stephan Ramon Garcia

Pomona Faculty Publications and Research

It has been observed many times, both in the Monthly and elsewhere, that the set of all quotients of prime numbers is dense in the positive real numbers. In this short note we answer the related question: "Is the set of all quotients of Gaussian primes dense in the complex plane?"


The Tornado Warning Process: A Review Of Current Research, Challenges, And Opportunities, Jerry Brotzge, William Donner Nov 2013

The Tornado Warning Process: A Review Of Current Research, Challenges, And Opportunities, Jerry Brotzge, William Donner

Sociology Faculty Publications and Presentations

With the unusually violent tornado season of 2011, there has been a renewed national interest, through such programs as NOAA's Weather Ready Nation initiative, to reevaluate and improve our tornado warning process. This literature review provides an interdisciplinary, end-to-end examination of the tornado warning process. Following the steps outlined by the Integrated Warning System, current research in tornado prediction and detection, the warning decision process, warning dissemination, and public response are reviewed, and some of the major challenges for improving each stage are highlighted. The progress and challenges in multi-day to short-term tornado prediction are discussed, followed by an examination …


Principles Of International Law For Multilateral Development Banks: The Obligation To Respect Human Rights, Robert T. Coulter, Leonardo A. Crippa, Emily Wann Nov 2013

Principles Of International Law For Multilateral Development Banks: The Obligation To Respect Human Rights, Robert T. Coulter, Leonardo A. Crippa, Emily Wann

Free, Prior and Informed Consent: Pathways for a New Millennium (November 1)

41 pages.

"January, 2009"

www.indianlaw.org


Indigenous Peoples’ Right Of Free Prior Informed Consent With Respect To Indigenous Lands, Territories And Resources (June 28, 2010), Indian Law Resource Center Nov 2013

Indigenous Peoples’ Right Of Free Prior Informed Consent With Respect To Indigenous Lands, Territories And Resources (June 28, 2010), Indian Law Resource Center

Free, Prior and Informed Consent: Pathways for a New Millennium (November 1)

3 pages.

"June 28, 2010"


Free, Prior And Informed Consent: Ilo 169 And Undrip, Kelsey Peterson Nov 2013

Free, Prior And Informed Consent: Ilo 169 And Undrip, Kelsey Peterson

Free, Prior and Informed Consent: Pathways for a New Millennium (November 1)

2 pages.

"Kelsey Peterson, American Indian Law Program Fellow, University of Colorado Law School Class of 2015"


Carrier-Envelope-Phase-Induced Asymmetries In Double Ionization Of Helium By An Intense Few-Cycle Xuv Pulse, Jean Marcel Ngoko Djiokap, N. L. Manakov, A. V. Meremianin, Anthony F. Starace Nov 2013

Carrier-Envelope-Phase-Induced Asymmetries In Double Ionization Of Helium By An Intense Few-Cycle Xuv Pulse, Jean Marcel Ngoko Djiokap, N. L. Manakov, A. V. Meremianin, Anthony F. Starace

Anthony F. Starace Publications

The carrier-envelope-phase (CEP) dependence of electron angular distributions in double ionization of He by an arbitrarily polarized, few-cycle, intense XUV pulse is formulated using perturbation theory (PT) in the pulse amplitude. Owing to the broad pulse bandwidth, interference of first- and second-order PT amplitudes produces asymmetric angular distributions sensitive to the CEP. The PT parametrization is shown to be valid by comparing with results of solutions of the full-dimensional, two-electron time-dependent Schrödinger equation for the case of linear polarization.


Harmonic Generation Spectroscopy With A Two-Colour Laser Field Having Orthogonal Linear Polarizations, T. S. Sarantseva, M. V. Frolov, N. L. Manakov, M. Yu. Ivanov, Anthony F. Starace Nov 2013

Harmonic Generation Spectroscopy With A Two-Colour Laser Field Having Orthogonal Linear Polarizations, T. S. Sarantseva, M. V. Frolov, N. L. Manakov, M. Yu. Ivanov, Anthony F. Starace

Anthony F. Starace Publications

The interpretation of many high-order harmonic generation (HHG) experiments is based on the assumption that the HHG yield of an atom can be factorized into (i) a laser-dependent ‘electron wave packet’ with rather simple properties, including a nearly universal shape, and (ii) an atomic photorecombination cross section. We show that this factorization is restricted to linearly polarized laser fields and fails in two-colour laser fields with orthogonal polarizations. At the same time, we show how two-colour HHG spectroscopy using orthogonally polarized intense fundamental and relatively weak second harmonic fields makes a complete experiment possible that enables the retrieval of the …