title: 15 yr of interstellar neutral hydrogen observed with the Interstellar Boundary Explorer

authors: Galli, A

abstract: The interactions of our heliosphere with the surrounding local interstellar medium (LISM) lead to a range of observable phenomena such as energetic neutral atoms (ENAs) from the boundary regions of the heliosphere and the influx of interstellar neutrals (ISNs) into the inner solar system. Hydrogen is the dominant neutral species in the LISM, but due to ionization and radiation pressure, only a fraction of the ISN H atoms reach the inner solar system close to Earth. Monitoring this signal therefore provides observational constraints on our assumptions of the LISM and the solar-activity-dependent loss processes inside the heliosphere. The IBEX-Lo instrument on board the Interstellar Boundary Explorer has been the only instrument so far to measure ISN H atoms directly, together with ISN D, He, Ne, O, and ENAs in the energy range from tens of eV to 2 keV. This study covers 15 yr of IBEX-Lo ISN H observations, i.e., more than one solar cycle and includes two solar minima when the ISN H signal in IBEX-Lo is strongest. Despite the very intense ISN He signal, the ISN H signal can be retrieved with appropriate knowledge of the instrument, choice of optimum observation season, and supporting modeling. The retrieved ISN H signal shows a clear anticorrelation with solar activity. The resulting ISN H maps are available in orbit format and in ecliptic coordinates and will be the basis for future more detailed comparison with heliosphere models.

text: 15 yr of interstellar neutral hydrogen observed with the Interstellar Boundary Explorer The interactions of our heliosphere with the surrounding local interstellar medium (LISM) lead to a range of observable phenomena such as energetic neutral atoms (ENAs) from the boundary regions of the heliosphere and the influx of interstellar neutrals (ISNs) into the inner solar system. Hydrogen is the dominant neutral species in the LISM, but due to ionization and radiation pressure, only a fraction of the ISN H atoms reach the inner solar system close to Earth. Monitoring this signal therefore provides observational constraints on our assumptions of the LISM and the solar-activity-dependent loss processes inside the heliosphere. The IBEX-Lo instrument on board the Interstellar Boundary Explorer has been the only instrument so far to measure ISN H atoms directly, together with ISN D, He, Ne, O, and ENAs in the energy range from tens of eV to 2 keV. This study covers 15 yr of IBEX-Lo ISN H observations, i.e., more than one solar cycle and includes two solar minima when the ISN H signal in IBEX-Lo is strongest. Despite the very intense ISN He signal, the ISN H signal can be retrieved with appropriate knowledge of the instrument, choice of optimum observation season, and supporting modeling. The retrieved ISN H signal shows a clear anticorrelation with solar activity. The resulting ISN H maps are available in orbit format and in ecliptic coordinates and will be the basis for future more detailed comparison with heliosphere models.

year: 2025-04-14

title: Experiment Databases: Creating a New Platform for Meta-Learning Research

authors: Vanschoren, Joaquin

subjects: computer science

abstract: Many studies in machine learning try to investigate what makes an algorithm succeed or fail on certain datasets. However, the field is still evolving relatively quickly, and new algorithms, preprocessing methods, learning tasks and evaluation procedures continue to emerge in the literature. Thus, it is impossible for a single study to cover this expanding space of learning approaches. In this paper, we propose a community-based approach for the analysis of learning algorithms, driven by sharing meta-data from previous experiments in a uniform way. We illustrate how organizing this information in a central database can create a practical public platform for any kind of exploitation of meta-knowledge, allowing effective reuse of previous experimentation and targeted analysis of the collected results.

text: Experiment Databases: Creating a New Platform for Meta-Learning Research Many studies in machine learning try to investigate what makes an algorithm succeed or fail on certain datasets. However, the field is still evolving relatively quickly, and new algorithms, preprocessing methods, learning tasks and evaluation procedures continue to emerge in the literature. Thus, it is impossible for a single study to cover this expanding space of learning approaches. In this paper, we propose a community-based approach for the analysis of learning algorithms, driven by sharing meta-data from previous experiments in a uniform way. We illustrate how organizing this information in a central database can create a practical public platform for any kind of exploitation of meta-knowledge, allowing effective reuse of previous experimentation and targeted analysis of the collected results.

year: 2008

title: Editorial Introduction: The utility and futility of 'the nation' in histories of Aotearoa New Zealand.

authors: Coleborne, Catharine

subjects: New Zealand

abstract: An introduction is presented which discusses articles in the issue on New Zealand history, including one on interracial rape and sexual violence in the 1860s, one on postcolonial methodology and the historical concept of the British World, and one on Whanganui Māori claims to the Whanganui River.

text: Editorial Introduction: The utility and futility of 'the nation' in histories of Aotearoa New Zealand. An introduction is presented which discusses articles in the issue on New Zealand history, including one on interracial rape and sexual violence in the 1860s, one on postcolonial methodology and the historical concept of the British World, and one on Whanganui Māori claims to the Whanganui River.

year: 2011