42 research outputs found
A flexible bimodal model with long-term survivors and different regression structures
No full textThe cure fraction models are useful to model lifetime data with long-term survivors. In this paper, we introduce a flexible cure rate survival model where the model parameters are related to covariates in different regression structures. The regression model allows to model jointly the location, scale and shape effects. The maximum likelihood method is employed to estimate the model parameters. We provide Monte Carlo simulation experiments to verify the performance of the maximum likelihood estimates for different sample sizes and cure rate percentages. Furthermore, some diagnostic measures to assess departures from model assumptions as well as to detect outlying observations are also considered. Finally, applications to real data are presented to show the usefulness of the new cure rate model.Lemonte, AJ (corresponding author), Univ Fed Rio Grande do Norte, Dept Stat, Rio Grande Do Norte, RN, Brazil.
[email protected]
Absence of juvenile effects confirmed in stable carbon and oxygen isotopes of European larch trees
No full textČlanek obravnava razmerja ogljikovih in kisikovih izotopov v branikah blizu stržena na prsni višini (cca 1,2 m) treh evropskih macesnov (Larix decidua Mill.), rastočih v mešanem gozdu s predraslimi hrasti in nasajenimi evropskimi macesni v zahodnem Walesu, Velika Britanija. Neklimatskega naraščajočega trenda v razmerjih ogljikovih izotopov, ki ga je sicer opaziti pri drugih vrstah v letih juvenilne rasti, ni, in tudi razmerje stabilnih izotopov ne kaže pomembnih trendov med odraščanjem drevesa. Rezultati iz prvih desetih branik ob strženu se bistveno ne razlikujejo od naslednjih dveh nizov desetih branik. O izostanku juvenilnega efekta v ogljikovih izotopih evropskega macesna so že poročali v zvezi z macesni, rastočimi v nesklenjenih sestojih v Franciji in to pripisali nezastrtosti krošenj in posledične neuporabe ogljikovega dioksida, ki ga pri dihanju oddajajo drevesa. Analizirana drevesa v zahodnem Walesu so rasla v nasadu s predraslimi hrasti, ki so bili starejši od podraslih macesnov. Macesni, kot svetloljubne drevesne vrste, so morali tekmovati za prostor in svetlobo, zato domnevamo, da je morebiten pojav juvenilnega efekta pri stabilnih izotopih prej posledica sprememb v hidravlični prevodnosti lesa, kot pa česa drugega. Ker današnja praksa izogibanja juvenilnega lesa omejuje potencial stabilnih izotopov drevesnih branik za dendroklimatološke in fiziološke raziskave, bi bile potrebnih dodatne raziskave o učinkih juvenilne rasti na pojav juvenilnega efekta v meritvah stabilnih izotopov
Improving the Efficiency of District Heating and Cooling Using a Geothermal Technology: Underground Thermal Energy Storage (UTES)
No full textFor efficient operation of heating and cooling grids, underground thermal energy storage (UTES) can be a key element. This is due to its ability to seasonally store heat or cold addressing the large mismatch between supply and demand. This technology is already available and there are many operational examples, both within and outside a district heating network. Given the range of available UTES technologies, they are feasible to install almost everywhere. Compared to other storage systems, UTES have the advantage of being able to manage large quantities and fluxes of heat without occupying much surface area, although the storage characteristics are always site specific and depend on the geological and geothermal characteristics of the subsoil. UTES can manage fluctuating production from renewable energy sources, both in the short and long term, and fluctuating demand. It can be used as an instrument to exploit heat available from various sources, e.g., solar, waste heat from industry, geothermal, within the same district heating system. The optimization of energy production, the reduction in consumption of primary energy and the reduction in emission of greenhouse gases are guaranteed with UTES, especially when coupled with district heating and cooling networks
Measures for concordance and discordance with applications in disease control and prevention
No full textBivariate binary response data appear in many applications. Interest goes most often to a parameterization of the joint probabilities in terms of the marginal success probabilities in combination with a measure for association, most often being the odds ratio. Using, for example, the bivariate Dale model, these parameters can be modelled as function of covariates. But the odds ratio and other measures for association are not always measuring the (joint) characteristic of interest. Agreement, concordance, and synchrony are in general facets of the joint distribution distinct from association, and the odds ratio as in the bivariate Dale model can be replaced by such an alternative measure. Here, we focus on the so-called conditional synchrony measure. But, as indicated by several authors, such a switch of parameter might lead to a parameterization that does not always lead to a permissible joint bivariate distribution. In this contribution, we propose a new parameterization in which the marginal success probabilities are replaced by other conditional probabilities as well. The new parameters, one homogeneity parameter and two synchrony/discordance parameters, guarantee that the joint distribution is always permissible. Moreover, having a very natural interpretation, they are of interest on their own. The applicability and interpretation of the new parameterization is shown for three interesting settings: quantifying HIV serodiscordance among couples in Mozambique, concordance in the infection status of two related viruses, and the diagnostic performance of an index test in the field of major depression disorders.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was only possible, thanks to the financial support of the Flemish Interuniversity Council (VLIR-UOS) in collaboration with Eduardo Mondlane University (UEM) through the DESAFIO Program. NH acknowledges funding from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation programme (grant no. 682540 TransMID) and the Special Research Fund of Hasselt University
Flow patterns around old sunspots and flare activity
No full textNew magnetic flux emerges significantly more probably in already
existing solar active regions. Based on the the Debrecen Observatory
photographic observations, several active regions are collected, where at least
one large, X-class flare was recorded, and emergence of new activity, birth
and quick motion of new umbrae was observed in the vicinity of old spots, the
new activity emerged in the center of the old active region.
Newly emerging
magnetic flux in older sunspot groups can be distinguished by its quicker and
generally westward proper motions. Umbrae of the new activity do not coalesce
with older umbrae of the same polarity, but both elastic and inelastic
collisions between them can be observed. Spots of the emerging new activity can
flow around old unipolar spots (presumably shallower structures,
“ω-loops”) westward, like a hydrodynamic flow around a cylinder, forming
a wake behind it. Collision of different polarities in the wake can lead to
large flares. The presence of old spots disturbs the normal emergence of the
new activity, so motions of the new spots are distorted by the flow, the new
emerging “Ω-loop” can be stuck between the umbrae of the old, tight
dipole, the orientation of the new dipole can be distorted by as much as 180◦.
The general direction of the flow around the old spots seems to depend on
the latitude, the angle between the motion axis and the E-W direction grows
with the latitude.
The intensive flare activity seems to be connected strongly
with the newly emerging magnetic flux; interacting of differently oriented
dipoles and the difference of the orientation of the emerging new dipole from
the ordinary Hale-Nicholson orientation is also significant. Simply large
gradients of magnetic fields (δ-configuration) are not enough, dynamical
processes (emergence of new flux, shearing or colliding motions of umbrae of
different magnetic polarity) must also be present for large flares
Erratum to: Observation of the B+ → Jψη′K+ decay
No full textIn the original article, information related to the author list has been corrected. The originally published wrong file has been replaced online
Truth and reconciliation at the grassroots : community truth processes in the Southern United States
No full textIncludes bibliographical references (leaves 94-98).Truth commissions are implemented in order to "deal with the past" in the context of a transition in government from authoritarian to democratic rule. At the center of a truth commission is a truth process that attempts to establish the experience of gross human rights abuse at the hands of the state, and does so in a way which places the victims of such abuse at the center of the process, through valuing victim testimony as "truth." It is done with the assumption in mind, that in order for a society, or community, to have healthy relations in the future, violent past experiences must be faced and dealt with. Communities at a local level have imitated the structure, goals and procedures of truth commissions in projects that have been termed "Unofficial Truth Projects." This thesis compares three case studies of unofficial truth projects which have taken place in the Southern United States in the past few years: The Greensboro Truth and Reconciliation Commission in Greensboro, North Carolina, which sought to establish a community reconciliation process 25 years after what has come to be known as the "Greensboro Massacre"; and two civil-society based truth processes, the Katrina National Justice Commission and the International Tribunal on Hurricanes Katrina and Rita, which seek to establish truth and gain reparations for human rights abuses which have taken place in the aftermath of Hurricane Katrina in New Orleans. The author considers various projects in a comparative manner, and through examining their histories, structures and ideological make-up, analyzes the processes in terms how these factors affect the ability for the project to: gain legitimacy as a truth process, generate resources and support, acknowledge victims' experiences, and engage the community in reconciliation efforts. The author also echoes the calls for a shift in paradigm in reconciliation and transitional justice literature, which would allow for a space to exist for truth processes that may be unofficial and fall outside a context of a formal transition. Such processes could still greatly benefit communities living in post-conflict contexts and with histories of racial and political violence, such as many communities in the Southern United States
Detective fiction in Cuban society and culture.
No full textPhDThe object of this thesis is to reach towards an understanding of Cuban society through a
study of its detective fiction and more particularly contemporary Cuban society through
the novels of the author and critic, Leonardo Padura Fuentes.
The method has been to trace the development of Cuban detective writing and to
read Padura Fuentes in the light of the work of twentieth century Western European
literary critics and philosophers including Raymond Williams, Antonio Gramsci, Terry
Eagleton, Roland Barthes, Jean Paul Sartre, Michel Foucault, Jean François Lyotard and
Jean Baudrillard in order to gain a better understanding of the social and historical
context from which this genre emerged.
By concentrating on the literary texts, I have explored readings which lead out into
an analysis of the broader philosophical, political and historical issues raised by the
Cuban revolution. Since it deals primarily with modes of deviance and notions of legality
and justice within the context of the modern state, detective fiction is particularly well
suited to this type of investigation. The intention is to show how this is as valid in the
Cuban context as it is in advanced capitalist societies where such research has already
been carried out with some success.
The thesis comprises an introduction, ten chapters and a conclusion. The chapters
are divided into three sections. Chapters 1 to 3 attempt a broad theoretical, historical and
socio-political analysis of the cultural reality within which the Cuban revolutionary
detective genre emerged. Chapters 4 to 6 analyse the Cuban detective narrative from its
inception in the early part of the twentieth century until the emergence of Leonardo
Padura Fuentes as the foremost exponent of the genre in Cuba after 1991. Chapters 7-
10 concentrate upon the work of Leonardo Padura Fuentes, offering a reading of his
detective tetralogy informed by the preceding discussion.
The contribution made by the thesis to knowledge of the subject is to build upon the
work of Seymour Menton and Amelia S. Simpson on the development of the Cuban
detective novel and to provide analyses of the pre-Revolutionary Cuban detective
narrative and the work of Leonardo Padura Fuentes for the first time in the English
language. The thesis concludes that the study of this popular genre in Cuba is of crucial
importance to the scholar who wishes to reach as full an understanding of the social
dynamics within that society as possible. In particular, it proves that Cuban detective
fiction provides a useful barometer of social change which records the shifts in the Cuban
Zeitgeist that have taken place over the past century
Publisher Erratum: Long-lived particle reconstruction downstream of the LHCb magnet (Eur. Phys. J. C, (2025), 85, (7), 10.1140/epjc/s10052-024-13686-6)
No full textThe original HTML-version of this article was revised. A number of typographical and editorial details were incorrectly implemented, and the Data and Code Availability Statements were wrongly given. In the abstract, line 11, the Λ symbol was boldfaced while it should have been. In page 1 there were two instances of the symbol “PP”, towards the end of the left column and the beginning of the right column, which should have been “pp”, without capitalization. At the beginning of Section 3, end of page 2 and beginning of page 3, the paragraph starting as “First, Long tracks..” and finishing with “muon chambers” was with indentation, and should not have been. In addition, it was starting as a new paragraph while it should have been started right after “in Fig. 1.”. Moreover, all sentences in this paragraph were starting with a line break while should not be. Overall, the paragraph should read as follows: “..as illustrated in Fig. 1. Long tracks traverse the full tracking system. They include hits in both the VELO and the T1–T3 stations, and optionally in TT (UT in the upgraded detector). Upstream tracks traverse only the VELO and the TT (UT) stations. They are typically produced by low momentum particles, which are bent away by the magnetic field, thus failing to reach the T1–T3 stations. Downstream tracks traverse both the TT (UT) and T1–T3 stations, but do not leave any hit in the VELO. They typically belong to decay products of long-lived particles decaying beyond the VELO, such as Λ or KS0 hadrons. VELO tracks have hits only in the VELO. They include large-angle or backward tracks, useful for the determination of the PV, as well as very low momentum tracks. T tracks have hits only in the T1–T3 stations. Similarly to Downstream tracks, they include the decay products of long-lived particles decaying far away from the PV, up to several metres. A significant fraction of tracks reconstructed in this category comes from secondary interactions with the material of the mechanical structures and back-scattering particles coming from the calorimeters and hadron shield behind the muon chambers.” In page 3, right column, line 13, “layer” should have been “layers”. In page 4, left column, lines 5–6, the J/ψ→μ+μ- decay descriptor was broken in two lines and should have been in a single line. In several places in the HTML-version the Λ and Λb0 particles were written using incorrect fonts, with the Λ symbol boldfaced and the b subscript slanted, while they both should have not been. The text justification in the caption of Figs. 13 and 22 was left and should have been full. Several figure captions used incorrect fonts for denoting the particles, inconsistently with the fonts in the main text. For example, in Fig. 2: π+π- and ψ in J/ψ were slanted and should not be; the subscripts S for KS0 and b for Λb were also slanted and should not be; the Λ symbol denoting the Λ and Λb particles were boldfaced and should not be. Captions of Figs. 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 and 27 are also affected. The Data Availability Statement in page 19 was “Data will be made available on reasonable request. [Author’s comment: The datasets generated during the current study are available from the corresponding author on reasonable request.].” and should have been “The LHCb experiment has agreed to the CERN open data policy summarised in https://opendata.cern.ch/docs/about. In particular, Level 1 data associated with this publication are made available on the CERN document server at http://cds.cern.ch/record/2908392/files/. These data contain material related to the paper that allows a reinterpretation of the results in the context of new theoretical models.” The Code Availability Statement in page 19 was “Code/software cannot be made available for reasons disclosed in the code availability statement. [Author’s comment: The code/software generated during the current study is not publicly available but is available from the corresponding author on reasonable request.].” and should have been “Specific analysis software/code used to produce the results shown in the publication is preserved within the LHCb collaboration internally and can be provided on reasonable request, provided it does not contain information that can be associated with unpublished results.” The original article has been corrected and the publisher apologizes for the inconvenience caused
Looking beyond general metrics for model comparison – lessons from an international model intercomparison study
No full textpeer reviewedInternational collaboration between research institutes and universities is a promising way to reach consensus on hydrological model development. Although comparative studies are very valuable for international cooperation, they do often not lead to very clear new insights regarding the relevance of the modelled processes. We hypothesise that this is partly caused by model complexity and the comparison methods used, which focus too much on a good overall performance instead of focusing on specific events. In this study, we use an approach that focuses on the evaluation of specific events and characteristics. Eight international research groups calibrated their hourly model on the Ourthe catchment in Belgium and carried out a validation in time for the Ourthe catchment and a validation in space for nested and neighbouring catchments. The same protocol was followed for each model and an ensemble of best performing parameter sets was selected. Although the models showed similar performances based on general metrics (i.e. Nash–Sutcliffe Efficiency), clear differences could be observed for specific events. The results illustrate the relevance of including a very quick flow reservoir preceding the root zone storage to model peaks during low flows and including a slow reservoir in parallel with the fast reservoir to model the recession for the Ourthe catchment. This intercomparison enhanced the understanding of the hydrological functioning of the catchment and, above all, helped to evaluate each model against a set of alternative models
