431 research outputs found
Testing EUV/X-ray Atomic Data for the Solar Dynamics Observatory
The Atmospheric Imaging Assembly (AIA) and the Exteme-ultraviolet Variability
Experiment (EVE) onboard the Solar Dynamics Observatory include spectral
windows in the X-ray/EUV band. Accuracy and completeness of the atomic data in
this wavelength range is essential for interpretation of the spectrum and
irradiance of the solar corona, and of SDO observations made with the AIA and
EVE instruments. Here we test the X-ray/EUV data in the CHIANTI database to
assess their completeness and accuracy in the SDO bands, with particular focus
on the 94A and 131A AIA passbands. Given the paucity of solar observations
adequate for this purpose, we use high-resolution X-ray spectra of the
low-activity solar-like corona of Procyon obtained with the Chandra Low Energy
Transmission Grating Spectrometer (LETGS). We find that while spectral models
overall can reproduce quite well the observed spectra in the soft X-ray range
ll 130A, they significantly underestimate
the observed flux in the 50-130A wavelength range. The model underestimates the
observed flux by a variable factor ranging from \approx 1.5, at short
wavelengths below \sim50A, up to \approx5-7 in the \sim 70-125A range. In the
AIA bands covered by LETGS, i.e. 94A and 131A, we find that the observed flux
can be underestimated by large factors (\sim 3 and \sim 1.9 respectively, for
the case of Procyon presented here). We discuss the consequences for analysis
of AIA data and possible empirical corrections to the AIA responses to model
more realistically the coronal emission in these passbands.Comment: 11 pages, 9 figures, accepted for publication on Ap
Temperature distribution of a non-flaring active region from simultaneous Hinode XRT and EIS observations
We analyze coordinated Hinode XRT and EIS observations of a non-flaring
active region to investigate the thermal properties of coronal plasma taking
advantage of the complementary diagnostics provided by the two instruments. In
particular we want to explore the presence of hot plasma in non-flaring
regions. Independent temperature analyses from the XRT multi-filter dataset,
and the EIS spectra, including the instrument entire wavelength range, provide
a cross-check of the different temperature diagnostics techniques applicable to
broad-band and spectral data respectively, and insights into cross-calibration
of the two instruments. The emission measure distribution, EM(T), we derive
from the two datasets have similar width and peak temperature, but show a
systematic shift of the absolute values, the EIS EM(T) being smaller than XRT
EM(T) by approximately a factor 2. We explore possible causes of this
discrepancy, and we discuss the influence of the assumptions for the plasma
element abundances. Specifically, we find that the disagreement between the
results from the two instruments is significantly mitigated by assuming
chemical composition closer to the solar photospheric composition rather than
the often adopted "coronal" composition (Feldman 1992). We find that the data
do not provide conclusive evidence on the high temperature (log T[K] >~ 6.5)
tail of the plasma temperature distribution, however, suggesting its presence
to a level in agreement with recent findings for other non-flaring regions.Comment: 14 pages, 15 figures. Accepted for publication in the Astrophysical
Journa
GIS in Geography Teaching
If it is true that every period of our history is marked by important revolutions which shaped its spirit and nature, today we can claim to live in what has been aptly defined, by a Pennsylvania State University project, as a “Geospatial Revolution”. Understanding the world in which we live, how it has changed and how the ways in which humans interact with it have changed, how people try to know, interpret and represent it, all provide crucial aspects for the planning of curricula, training courses and in the production of appropriate contents for them.
GIS represents an effective tool for teaching the understanding of space and place. GIS finds application in various fields from natural science and geology to sociology and anthropology, from political sciences, economics and urban studies to archaeology and history. The use of this tool enables the introduction of research methods in geography teaching, leading, for example, to the acquisition of the ability to create a conceptual model of reality that can be studied as well as to select the most useful data for this purpose, to interpret it independently, and to represent it effectively
Investigating the reliability of coronal emission measure distribution diagnostics using 3D radiative MHD simulations
Determining the temperature distribution of coronal plasmas can provide
stringent constraints on coronal heating. Current observations with the Extreme
ultraviolet Imaging Spectrograph onboard Hinode and the Atmospheric Imaging
Assembly onboard the Solar Dynamics Observatory provide diagnostics of the
emission measure distribution (EMD) of the coronal plasma.
Here we test the reliability of temperature diagnostics using 3D radiative
MHD simulations. We produce synthetic observables from the models, and apply
the Monte Carlo Markov chain EMD diagnostic. By comparing the derived EMDs with
the "true" distributions from the model we assess the limitations of the
diagnostics, as a function of the plasma parameters and of the signal-to-noise
of the data.
We find that EMDs derived from EIS synthetic data reproduce some general
characteristics of the true distributions, but usually show differences from
the true EMDs that are much larger than the estimated uncertainties suggest,
especially when structures with significantly different density overlap along
the line-of-sight. When using AIA synthetic data the derived EMDs reproduce the
true EMDs much less accurately, especially for broad EMDs. The differences
between the two instruments are due to the: (1) smaller number of constraints
provided by AIA data, (2) broad temperature response function of the AIA
channels which provide looser constraints to the temperature distribution.
Our results suggest that EMDs derived from current observatories may often
show significant discrepancies from the true EMDs, rendering their
interpretation fraught with uncertainty. These inherent limitations to the
method should be carefully considered when using these distributions to
constrain coronal heating.Comment: Accepted for publication on The Astrophysical Journal. 25 pages, 29
figures. Paper version with full resolution images and appendixes can be
found at: http://folk.uio.no/bdp/papers/3dEMD_ptesta.pd
Fisiología térmica de un depredador Dasythemis sp. (Odonata: Libellulidae) y su presa Hypsiboas pellucens (Anura: Hylidae) y sus posibles implicaciones frente al cambio climático.
La temperatura es considerada uno de los factores abióticos más importante dentro de la biología de los organismos. El constante cambio de temperatura como consecuencia del cambio climático puede influir en las respuestas fisiológicas de los organismos y en la estructura de las comunidades. El objetivo principal de este estudio es determinar la variación en los parámetros fisiológicos térmicos en un depredador y su presa (Dasythemis sp. e Hypsiboas pellucens), que coexisten en una misma poza en las cercanías de Mindo (Pichincha), y evaluar su vulnerabilidad ante posibles cambios de temperatura ambiental en el futuro. Mediante el uso de un protocolo de rampa que cambia la temperatura a una tasa de 0.25°C min-1, se determinó la Temperatura Crítica Máxima (CTmax), la Temperatura Crítica Mínima (CTmin) y el rango de tolerancia térmica (CTmax – CTmin) de ambas especies. Para el desempeño de la presa, se determinó la velocidad máxima de escape a diferentes temperaturas, se determinó la temperatura preferida de ambas especies mediante el uso de un gradiente térmico. Se registró la temperatura microambiental de las charcas donde ambas especies fueron colectadas durante el periodo de marzo a diciembre del 2016 y se comparó su máximo valor con el CTmax de cada especie para determinar la vulnerabilidad relativa al cambio de temperatura ambiental. Las tolerancias térmicas máximas y mínimas fueron 45.5°C y 6.62°C para el Dasythemis sp. y 40.4°C y 8.1°C para la Hypsiboas pellucens. La temperatura máxima registrada en su microambiente fue 38.6°C y la temperatura mínima 15.9°C. La velocidad máxima de escape fue 86.72 cm gr-1 s-1 y una temperatura óptima de 28.1°C. La temperatura media preferida de la presa fue de 24.4°C y del depredador de 23.4°C. Se concluyó que existen diferencias significativas en las tolerancias térmicas entre el depredador y la presa, y la temperatura preferida de la presa está por sobre la del depredador. Los renacuajos tuvieron una Tolerancia al calentamiento (WT por sus siglas en inglés) más bajo (1.85°C) que el de las larvas de libélula (6.88°C), y serían más vulnerables frente a cambios ambientales futuros. Sin embargo, la temperatura óptima y la frecuencia de temperaturas en el microambiente indican que en el futuro cercano el cambio climático podría mejorar el desempeño de las especies
Il ciclo riflessivo di Gibbs e la Ricerca-formazione: una proposta di ricerca
Nell’ambito della formazione il tema della riflessività ha dato origine a un variegato universo di pratiche. Dare valore alla riflessione sull’esperienza significa superare la tradizionale separazione tra teoria e pratica, che vede l’esperienza unicamente come il luogo in cui si applicano saperi e schemi d’azione appresi altrove. Non è semplice
raccogliere evidenze di come questo processo riflessivo si inneschi, quali possano essere i livelli del suo sviluppo e che risultati, in termini di cambiamenti e nuove consapevolezze, provochi nei soggetti che vi partecipano. Gibbs (1988) con il suo schema di riflessione sulla pratica suggerisce sei dimensioni di riferimento, che spingono alla riflessione individuale o collettiva. Questo modello, di per sé situato e non generalizzabile a una famiglia di situazioni, presenta delle potenzialità non ancora esplorate. Il presente contributo propone un progetto di ricerca fondato sulla ricerca-formazione che, insieme a docenti di diversi ordini scolastici utilizzi questo modello per l’attivazione, l’analisi e la valutazione di processi riflessivi sul proprio lavoro. Presenteremo il quadro di ricerca, individuando le intenzionalità alla base delle scelte metodologiche. Si analizzerà l’utilizzo di strumenti quantitativi a sostegno del quadro
di ricerca qualitativo. L’intreccio di strumenti quantitativi e qualitativi sarà funzionale a sostenere l’esportabilità del processo e supportare la capacità del cambiamento nel docente.In the field of education, the theme of reflexivity has given rise to a diverse universe of practices. To value reflection on experience is to overcome the traditional separation of theory and practice, which sees experience solely as the place where knowledge and patterns of action learned elsewhere are applied. It is not easy to gather evidence of how this reflective process is triggered, what the levels of its development might be, and what results, in terms of changes and new awareness, it causes in the subjects who participate in it. Gibbs (1988) with his schema of reflection on practice suggests
six reference dimensions, which prompt individual or collective reflection. This model, itself situated and not generalizable to a family of situations, has potential that has not yet been explored. This paper proposes a research-training-based research project that,
together with teachers from different grade levels, will apply this model for the activation, analysis and evaluation of reflective processes on teachers’ actions. We will present the research framework, identifying the intentionalities behind the methodological choices.
We will explore the use of quantitative tools to support the qualitative research framework, functional for the exportability of the process and the triggering of changes in teachers
A retrospective analysis focusing on a group of patients with dual diagnosis treated by both mental health and substance use services
OBJECTIVE: To highlight which demographic, familial, premorbid, clinical, therapeutic, rehabilitative, and assistance factors were related to dual diagnosis, which, in psychiatry, means the co-occurrence of both mental disorder and substance use in the same patient.
METHODS: Our sample (N=145) was chosen from all outpatients with a dual diagnosis treated from January 1, 2012 to July 31, 2012 by both the Mental Health Service and the Substance Use Service of Modena and Castelfranco Emilia, Italy. Patients who dropped out during the study period were excluded. Demographic data and variables related to familial and premorbid history, clinical course, rehabilitative programs, social support and nursing care, and outcome complications were collected. The patients' clinical and functioning conditions during the study period were evaluated.
RESULTS: Our patients were mostly men suffering from a cluster B personality disorder. Substance use was significantly more likely to precede psychiatric disease (P<0.001), and 60% of the sample presented a positive familial history for psychiatric or addiction disease or premorbid traumatic factors. The onset age of substance use was related to the period of psychiatric treatment follow-up (P<0.001) and the time spent in rehabilitative facilities (P<0.05), which, in turn, was correlated with personality disorder diagnosis (P<0.05). Complications, which presented in 67% of patients, were related to the high number of psychiatric hospitalizations (P<0.05) and professionals involved in each patient's treatment (P<0.05). Males more frequently presented familial, health, and social complications, whereas females more frequently presented self-threatening behavior (P<0.005).
CONCLUSION: It was concluded that the course of dual diagnosis may be chronic, severe, and disabling, requiring many long-term therapeutic and rehabilitative programs to manage various disabilities
Weight control and behavior rehabilitation in a patient suffering from Prader Willi syndrome
Background
This study reports a case of Prader Willi syndrome (PWS), a genomic imprinting disease related to chromosome regions 15q11.2–q13 15, which includes hypothalamic dysfunction leading to hyperphagia, obesity, shortness, sleep abnormalities. Our case is extremely severe, in comparison to other PWS cases described in literature, due to the association with severe emotional and psychiatric symptoms: oppositional behaviour, rigidity of thought, skin picking and pathological hoarding.
Case presentation
We described the case of a Caucasian male patient suffering from PWS, treated in outpatient care by local Mental Health Centre and supported by Social Service, who was admitted to a residential rehabilitative facility. After a 2-year follow-up, the patient showed a global improvement in symptoms and functioning, as registered by the rating scales administered. At the end of observation period, we also reported an important improvement in weight control, reducing the risk of obesity and related diseases, therefore improving the prognosis of life.
Conclusion
This case highlights the need for long-term, individualized and multi-professional treatment in patients suffering from a complex genetic syndrome with both organic and psychological alterations, for which medical care setting and pharmacological treatments are not sufficient. Clinical observation of this case leads us to compare PWS to drug addiction and indirectly endorse the neurophysiological hypothesis that food and drugs stimulate the same brain circuits in the limbic system
Functional Structure of Spontaneous Sleep Slow Oscillation Activity in Humans
Background
During non-rapid eye movement (NREM) sleep synchronous neural oscillations between neural silence (down state) and neural activity (up state) occur. Sleep Slow Oscillations (SSOs) events are their EEG correlates. Each event has an origin site and propagates sweeping the scalp. While recent findings suggest a SSO key role in memory consolidation processes, the structure and the propagation of individual SSO events, as well as their modulation by sleep stages and cortical areas have not been well characterized so far.
Methodology/Principal Findings
We detected SSO events in EEG recordings and we defined and measured a set of features corresponding to both wave shapes and event propagations. We found that a typical SSO shape has a transition to down state, which is steeper than the following transition from down to up state. We show that during SWS SSOs are larger and more locally synchronized, but less likely to propagate across the cortex, compared to NREM stage 2. Also, the detection number of SSOs as well as their amplitudes and slopes, are greatest in the frontal regions. Although derived from a small sample, this characterization provides a preliminary reference about SSO activity in healthy subjects for 32-channel sleep recordings.
Conclusions/Significance
This work gives a quantitative picture of spontaneous SSO activity during NREM sleep: we unveil how SSO features are modulated by sleep stage, site of origin and detection location of the waves. Our measures on SSOs shape indicate that, as in animal models, onsets of silent states are more synchronized than those of neural firing. The differences between sleep stages could be related to the reduction of arousal system activity and to the breakdown of functional connectivity. The frontal SSO prevalence could be related to a greater homeostatic need of the heteromodal association cortices
The snow load in Europe and the climate change
It is often assumed that, as a consequence of global warming, a reduction of snow load on the ground should be expected. In reality, snow load is often depending on local orographic situations that can determine an increase of its height, even when the average snow height over the surrounding areas is reduced. Large snow loads on roofs during the winter season of 2005–2006 led to over 200 roof collapses in Central Europe. To proceed with the adaptation of the European standards for important buildings and infrastructures to the implications of climate change, the expected changes in the climatic loading shall be assessed in terms of the Eurocodes concept for characteristic values of variable climatic actions. The paper presents a procedure for derivation of snow load on ground from data on daily temperatures and precipitation. In addition, it allows to derive the characteristic snow loads from climate change projections and thus to evaluate the future trends in variation of snow loading. Analysis of these trends for the Italian territory is performed by comparing the results for several subsequent time periods of thirty years, with those obtained for the reference period 1951–1980. Results presented show a significant increase in the snow loading for the period 1981–2010 in many regions in north and east Italy in comparison with the reference period. It is suggested that a European project on snow load map shall be started, in order to help National Competent Authorities to redraft the national snow load maps for design with the Eurocodes
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