397 research outputs found
Framework Programmable Platform for the Advanced Software Development Workstation (FPP/ASDW). Demonstration framework document. Volume 1: Concepts and activity descriptions
The Framework Programmable Software Development Platform (FPP) is a project aimed at effectively combining tool and data integration mechanisms with a model of the software development process to provide an intelligent integrated software development environment. Guided by the model, this system development framework will take advantage of an integrated operating environment to automate effectively the management of the software development process so that costly mistakes during the development phase can be eliminated. The Advanced Software Development Workstation (ASDW) program is conducting research into development of advanced technologies for Computer Aided Software Engineering (CASE)
Solar total irradiance in cycle 23
The apparently unusual behaviour of the TSI during the most recent minimum of
solar activity has been interpreted as evidence against solar surface magnetism
as the main driver of the secular change in the TSI. We test claims that the
evolution of the solar surface magnetic field does not reproduce the observed
TSI in cycle 23. We use sensitive, 60-minute averaged MDI magnetograms and
quasi-simultaneous continuum images as an input to our SATIRE-S model and
calculate the TSI variation over cycle 23, sampled roughly twice-monthly. The
computed TSI is then compared to the PMOD composite of TSI measurements and to
the data from two individual instruments, SORCE/TIM and UARS/ACRIM II, that
monitored the TSI during the declining phase of cycle 23 and over the previous
minimum in 1996, respectively. Excellent agreement is found between the trends
shown by the model and almost all sets of measurements. The only exception is
the early, i.e. 1996 to 1998, PMOD data. Whereas the agreement between the
model and the PMOD composite over the period 1999-2009 is almost perfect, the
modelled TSI shows a steeper increase between 1996 and 1999 than implied by the
PMOD composite. On the other hand, the steeper trend in the model agrees
remarkably well with the ACRIM II data. A closer look at the VIRGO data, that
make the basis of the PMOD composite after 1996, reveals that only one of the
two VIRGO instruments, the PMO6V, shows the shallower trend present in the
composite, whereas the DIARAD measurements indicate a steeper trend. We
conclude that (1) the sensitivity changes of the PMO6V radiometers within VIRGO
during the first two years have very likely not been correctly evaluated, and
that (2) the TSI variations over cycle 23 and the change in the TSI levels
between the minima in 1996 and 2008 are consistent with the solar surface
magnetism mechanism
Household ecology and out-migration among ethnic Karen along the Thai-Myanmar border
Local migration in developing-world settings, particularly among rural populations, is an important yet understudied demographic process. Research on migration in such populations can help us test and inform anthropological and demographic theory. Furthermore, it can lead to a better understanding of modern population distributions and epidemiologic landscapes
A new approach to long-term reconstruction of the solar irradiance leads to large historical solar forcing
The variable Sun is the most likely candidate for natural forcing of past
climate change on time scales of 50 to 1000 years. Evidence for this
understanding is that the terrestrial climate correlates positively with solar
activity. During the past 10,000 years, the Sun has experienced substantial
variations in activity and there have been numerous attempts to reconstruct
solar irradiance. While there is general agreement on how solar forcing varied
during the last several hundred years --- all reconstructions are proportional
to the solar activity --- there is scientific controversy on the magnitude of
solar forcing. We present a reconstruction of the Total and Spectral Solar
Irradiance covering 130 nm--10 m from 1610 to the present with annual
resolution and for the Holocene with 22-year resolution. We assume that the
minimum state of the quiet Sun in time corresponds to the observed quietest
area on the present Sun. Then we use available long-term proxies of the solar
activity, which are Be isotope concentrations in ice cores and 22-year
smoothed neutron monitor data, to interpolate between the present quiet Sun and
the minimum state of the quiet Sun. This determines the long-term trend in the
solar variability which is then superposed with the 11-year activity cycle
calculated from the sunspot number. The time-dependent solar spectral
irradiance from about 7000 BC to the present is then derived using a
state-of-the-art radiation code. We derive a total and spectral solar
irradiance that was substantially lower during the Maunder minimum than
observed today. The difference is remarkably larger than other estimations
published in the recent literature. The magnitude of the solar UV variability,
which indirectly affects climate is also found to exceed previous estimates. We
discuss in details the assumptions which leaded us to this conclusion.Comment: 9 pages, 5 figures, accepted for publication in
Astronomy&Astrophysic
A review of technological innovations leading to modern endovascular brain aneurysm treatment
Tools and techniques utilized in endovascular brain aneurysm treatment have undergone rapid evolution in recent decades. These technique and device-level innovations have allowed for treatment of highly complex intracranial aneurysms and improved patient outcomes. We review the major innovations within neurointervention that have led to the current state of brain aneurysm treatment
Parallel Tempering: Theory, Applications, and New Perspectives
We review the history of the parallel tempering simulation method. From its
origins in data analysis, the parallel tempering method has become a standard
workhorse of physiochemical simulations. We discuss the theory behind the
method and its various generalizations. We mention a selected set of the many
applications that have become possible with the introduction of parallel
tempering and we suggest several promising avenues for future research.Comment: 21 pages, 4 figure
Marine phytoplankton community composition data from the Belgian part of the North Sea, 1968-2010
The Belgian Phytoplankton Database (BPD) is a comprehensive data collection comprising quantitative phytoplankton cell counts from multiple research projects conducted since 1968. The collection is focused on the Belgian part of the North Sea, but also includes data from the French and the Dutch part of the North Sea. The database includes almost 300 unique sampling locations and more than 3,000 sampling events resulting in more than 86,000 phytoplankton cell count records. The dataset covers two periods: 1968 to 1978 and 1994 to 2010. The BPD can be accessed online and provides high quality phytoplankton count data. The species taxonomy is updated, and the count values are quality checked and standardized. Important metadata like sampling date, sampling location, sampling depth and methodology is provided and standardized. Additionally, associated abiotic data and biovolume values are available. The dataset allows to conduct analyses of long-term temporal and spatial trends in phytoplankton community structure in the southern part of the North Sea, including changes in phytoplankton phenology and seasonality
Facial expressions depicting compassionate and critical emotions: the development and validation of a new emotional face stimulus set
Attachment with altruistic others requires the ability to appropriately process affiliative and kind facial cues. Yet there is no stimulus set available to investigate such processes. Here, we developed a stimulus set depicting compassionate and critical facial expressions, and validated its effectiveness using well-established visual-probe methodology. In Study 1, 62 participants rated photographs of actors displaying compassionate/kind and critical faces on strength of emotion type. This produced a new stimulus set based on N = 31 actors, whose facial expressions were reliably distinguished as compassionate, critical and neutral. In Study 2, 70 participants completed a visual-probe task measuring attentional orientation to critical and compassionate/kind faces. This revealed that participants lower in self-criticism demonstrated enhanced attention to compassionate/kind faces whereas those higher in self-criticism showed no bias. To sum, the new stimulus set produced interpretable findings using visual-probe methodology and is the first to include higher order, complex positive affect displays
Solar irradiance variability: a six-year comparison between SORCE observations and the SATIRE model
Aims: We investigate how well modeled solar irradiances agree with
measurements from the SORCE satellite, both for total solar irradiance and
broken down into spectral regions on timescales of several years. Methods: We
use the SATIRE model and compare modeled total solar irradiance (TSI) with TSI
measurements between 2003 and 2009. Spectral solar irradiance over 200-1630nm
is compared with the SIM instrument on SORCE between 2004 and 2009 during a
period of decline from moderate activity to the recent solar minimum in 10 nm
bands and for three spectral regions of significant interest: the UV integrated
over 200-300nm, the visible over 400-691nm and the IR between 972-1630 nm.
Results: The model captures 97% of observed TSI variation. In the spectral
comparison, rotational variability is well reproduced, especially between 400
and 1200 nm. The magnitude of change in the long-term trends is many times
larger in SIM at almost all wavelengths while trends in SIM oppose SATIRE in
the visible between 500 and 700nm and between 1000 and 1200nm. We discuss the
remaining issues with both SIM data and the identified limits of the model,
particularly with the way facular contributions are dealt with, the limit of
flux identification in MDI magnetograms during solar minimum and the model
atmospheres in the IR employed by SATIRE. It is unlikely that improvements in
these areas will significantly enhance the agreement in the long-term trends.
This disagreement implies that some mechanism other than surface magnetism is
causing SSI variations, in particular between 2004 and 2006, if the SIM data
are correct. Since SATIRE was able to reproduce UV irradiance between 1991 and
2002 from UARS, either the solar mechanism for SSI variation fundamentally
changed around the peak of cycle 23, or there is an inconsistency between UARS
and SORCE UV measurements. We favour the second explanation.Comment: 14 pages, 13 figure
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