182 research outputs found
Sepsi e shock settico in Terapia Intensiva Pediatrica (TiPed): esplorazione dei fattori diagnostici, terapeutici e prognostici in pazienti pediatrici critici con infezione
No full textBackground:
Sepsis and septic shock are leading cause of mortality and morbidity among children globally, thus requiring prompt diagnosis, intervention, and prognostication. From an interventional point of view, the choice of vasoactive agent for fluid-refractory septic shock (FRSS) in pediatric patients remains unclear. Similarly, from a diagnostic and prognostic point of view, the ideal organ-dysfunction score for risk assessment upon admission for pediatric sepsis requires further clarification.
Objectives:
To investigate extensively the diagnostic, therapeutic and prognostic factors of critically ill children admitted to the Pediatric Intensive Care Unit (PICU) with sepsis and septic shock.
Methods:
This is a sequence of three studies:
1. Systematic review and meta-analysis on vasoactive agents in FRSS
2. Single-center retrospective observational cohort study on patients with sepsis admitted to the PICU from January 2010 to December 2019.
3. Multi-center prospective observational cohort study on patients admitted to 8 Italian PICUs with a diagnosis of infection from February 2022 to January 2024 comparing prognostic accuracy of different organ dysfunction scores for sepsis.
Results:
1. Systematic Review: Of 26,284 identified articles, 13 met inclusion criteria, including a total of 997 children. Twelve studies included 748 patients receiving a single vasoactive agent. Of these, 361 received dopamine, 271 epinephrine, and 116 norepinephrine. Pooled estimate of mortality was 11% (CI 3%-36%) for patients receiving dopamine, 17% (CI 6%-37%) for patients receiving epinephrine, 7% (CI 1%-48%) for patients receiving norepinephrine. Four studies (3 RCTs, 1 observational cohort studies) addressed the comparison between patients receiving first-line dopamine (176 patients) and patients receiving first-line epinephrine (142 patients). The prevalence ratio overall favored the administration of epinephrine (PR 1.38, CI 0.81-2.38), however not showing statistical significance.
2. Retrospective Cohort Study: Sixty patients with sepsis were identified, 4 (6.7%) died, 7 (11.7%) developed new disability, 26 (43.3%) experienced prolonged length of stay, 21 (35%) prolonged invasive MV. The prognostic ability in mortality discrimination was significantly higher for organ-dysfunction scores, with PELOD-2 showing the best performance (AUROC 0.924, 95% CI 0.837-1.000), significantly better than SIRS 3 criteria (0.924 vs 0.509, p=0.009), SIRS 4 criteria (0.924 vs 0.509, p<0.001) and severe sepsis (0.924 vs 0.527, p<0.001).
3. Prospective Cohort Study: Of 466 enrolled patients, 20 died (4.63%). Median duration of mechanical ventilation was 3 days, median PICU LOS was 5 days for the overall sample. Patients meeting the International Pediatric Sepsis Consensus Conference (IPSCC) sepsis criteria had higher mortality (6.61%, p=0.027), higher rate of oncologic/hematologic (13.79%, p<0.001) and transplantologic (3.45%, p=0.007) comorbidities, longer mechanical ventilation duration (4 days, IQR 2 – 9, p=0.003) and PICU LOS (5.5 days, IQR 3 – 11, p=0.002). Prediction power for the primary outcome was better than that of the IPSCC criteria (AUROC 0.5774) for pSOFA Sclapbach (AUROC 0.8789, p<0.001), pSOFA Matics (AUROC 0.8855, p<0.001), pSOFA Shime (AUROC 0.9211, p<0.001), P-MODS (AUROC 0.8168, p<0.001) calculated at Day 1, yielding similar results when calculated at Day 2.
Conclusions:
This project highlights and emphasize the need for high-quality data in both interventional and prognostic domains for sepsis. Our systematic review has contributed valuable insights regarding the primary vasoactive agent of choice for patients with FRSS, which presently stands as epinephrine. Regardind the prognostic domains, our retrospective and prospective studies have confirmed a recent body of pediatric and adult evidence supporting the use of organ dysfunction scores for prognostication in infections and sepsis
Finding words and word structure in artificial speech: the development of infants' sensitivity to morphosyntactic regularities
No full textTo achieve language proficiency, infants must find the building blocks of speech and master the rules governing their legal combinations. However, these problems are linked: words are also built according to rules. Here, we explored early morphosyntactic sensitivity by testing when and how infants could find either words or within-word structure in artificial speech snippets embodying properties of morphological constructions. We show that 12-month-olds use statistical relationships between syllables to extract words from continuous streams, but find word-internal regularities only if the streams are segmented. Seven-month-olds fail both tasks. Thus, 12-month-olds infants possess the resources to analyze the internal composition of words if the speech contains segmentation information. However, 7-month-old infants may not possess them, although they can track several statistical relations. This developmental difference suggests that morphosyntactic sensitivity may require computational resources extending beyond the detection of simple statistics
Words and possible words in early language acquisition
No full textIn order to acquire language, infants must extract its building blocks words and master the rules governing their legal combinations from speech. These two problems are not independent, however: words also have internal structure. Thus, infants must extract two kinds of information from the same speech input. They must find the actual words of their language. Furthermore, they must identify its possible words, that is, the sequences of sounds that, being morphologically well formed, could be words. Here, we show that infants' sensitivity to possible words appears to be more primitive and fundamental than their ability to find actual words. We expose 12- and 18-month-old infants to an artificial language containing a conflict between statistically coherent and structurally coherent items. We show that 18-month-olds can extract possible words when the familiarization stream contains marks of segmentation, but cannot do so when the stream is continuous. Yet, they can find actual words from a continuous stream by computing statistical relationships among syllables. By contrast, 12-month-olds can find possible words when familiarized with a segmented stream, but seem unable to extract statistically coherent items from a continuous stream that contains minimal conflicts between statistical and structural information. These results suggest that sensitivity to word structure is in place earlier than the ability to analyze distributional information. The ability to compute nontrivial statistical relationships becomes fully effective relatively late in development, when infants have already acquired a considerable amount of linguistic knowledge. Thus, mechanisms for structure extraction that do not rely on extensive sampling of the input are likely to have a much larger role in language acquisition than general-purpose statistical abilities. (C) 2013 Published by Elsevier Inc
Resource Management Policies for Cloud-based Interactive 3D Applications
No full textThe increasing interest for the cloud computing paradigm is leading several different applications and services moving to the 'cloud'. Those range from general storage and computing services to document management systems and office applications. A new challenge is the migration to the cloud of interactive 3D applications, especially those designed for professional usage (e.g., scientific data visualizers, CAD instruments, 3D medical modeling applications). Among the several hurdles rising from some specific hardware and software requirements, an important issue to address is the definition of novel management policies that can properly support these applications, namely, that ensure efficient resource utilization together with a sufficient quality perceived by users. This paper presents some preliminary results in this direction and discusses some possible future work in this field. Our work is part of a wider project aiming at developing a complete architecture to offer interactive 3D applications in a cloud computing environment. Hence, we refer to this particular solution in this stud
Ahab's leg dilemma: on the design of a controlled experiment
No full textTo meet stakeholder non-technical background, requirements are often presented
by analysts in terms of scenarios. While translating requirements into
scenarios, details and over-specifications (called Ahab's Legs) need to be added
to make requirements concrete and understandable to stakeholders. Despite the
expected benefits that they should convey, Ahab's Legs could disturb the
requirement validation session. They can, in fact, distract the attention of
stakeholders. Valuable discussion time may be wasted when focusing on irrelevant
details rather than on the actually relevant ones.
In the present paper, we address the Ahab's Leg dilemma and its potential
impact on requirement validation sessions. We discuss how to measure the
distraction due to Ahab's Legs and what are the possible approaches an analyst
can adopt to limit it. Moreover, we present the design of a controlled
experiment devoted to measure the impact of Ahab's Legs on requirement
validation sessions. In particular, the experiment is meant to (1) estimate
the magnitude of the distracting effect, and to (2) assess one of the most
promising way to alleviate their negative effect, i.e. by making stakeholder
aware of the Ahab's Legs before the validation session
Discovering words and rules from speech input: an investigation into early morphosyntactic acquisition mechanisms
No full textTo acquire language proficiently, learners have to segment fluent speech
into units – that is, words -, and to discover the structural regularities underlying
word structure. Yet, these problems are not independent: in varying degrees, all
natural languages express syntax as relations between nonadjacent word
subparts. This thesis explores how developing infants come to successfully solve
both tasks. The experimental work contained in the thesis approaches this issue
from two complementary directions: investigating the computational abilities of
infants, and assessing the distributional properties of the linguistic input directed
to children.
To study the nature of the computational mechanisms infants use to
segment the speech stream into words, and to discover the structural regularities
underlying words, I conducted seventeen artificial grammar studies. Along these
experiments, I test the hypothesis that infants may use different mechanisms to
learn words and word-internal rules. These mechanisms are supposed to be
triggered by different signal properties, and possibly they become available at
different stages of development. One mechanism is assumed to compute the
distributional properties of the speech input. The other mechanism is
hypothesized to be non-statistical in nature, and to project structural regularities
without relying on the distributional properties of the speech input.
Infants at different ages (namely, 7, 12 and 18 months) are tested in their
abilities to detect statistically defined patterns, and to generalize structural
regularities appearing inside word-like units. Results show that 18-month-old
infants can both extract statistically defined sequences from a continuous stream
(Experiment 12), and find internal-word rules only if the familiarization stream is
segmented (Experiments 13 and 14). Twelve-month-olds can also segment words from a continuous stream (Experiment 5), but they cannot detect wordstraddling
sequences even if they are statistically informative (Experiments 15
and 16). In contrast, they readily generalize word-internal regularities to novel
instances after exposure to a segmented stream (Experiments 1-3 and 17), but not
after exposure to a continuous stream (Experiment 4). Instead, 7-month-olds do
not compute either statistics (Experiments 10 and 11) or within-word relations
(Experiments 6 and 7), regardless of input properties. Overall, the results suggest
that word segmentation and structural generalization rely on distinct
mechanisms, requiring different signal properties to be activated --that is, the
presence of segmentation cues is mandatory for the discovery of structural
properties, while a continuous stream supports the extraction of statistically
occurring patterns. Importantly, the two mechanisms have different
developmental trajectories: generalizations became readily available from 12
months, while statistical computations remain rather limited along the first year.
To understand how the computational selectivities and the limits of the
computational mechanisms match up with the limitations and the properties of
natural language, I evaluate the distributional properties of speech directed to
children. These analyses aim at assessing with quantitative and qualitative
measures whether the input children listen to may offer a reliable basis for the
acquisition of morphosyntactic rules. I choose to examine Italian, a language with
a rich and complex morphology, evaluating whether the word forms used in
speech directed to children would provide sufficient evidence of the
morphosyntactic rules of this language. Results show that the speech directed to
children is highly systematic and consistent. The most frequently used word
forms are also morphologically well-formed words in Italian: thus, frequency
information correlates with structural information -- such as the morphological
structure of words. While a statistical analysis of the speech input may provide a
small set of words occurring with high frequency, how learners come to extract
structural properties from them is another problem. In accord with the results of
the infant studies, I propose that structural generalizations are projected on a
different basis than statistical computations.
Overall, the results of both the artificial grammar studies an the corpus analysis are compatible with the hypothesis that the tasks of segmenting words from fluent speech, and that of learning structural regularities underlying word
structure rely on statistical and non-statistical cues respectively, placing
constraints on computational mechanisms having different nature and
selectivities in early development
Zebrafish: a suitable tool for the study of cell signaling in bone
No full textIn recent decades, many studies using the zebrafish model organism have been performed. Zebrafish, providing genetic mutants and reporter transgenic lines, enable a great number of studies aiming at the investigation of signaling pathways involved in the osteoarticular system and at the identification of therapeutic tools for bone diseases. In this review, we will discuss studies which demonstrate that many signaling pathways are highly conserved between mammals and teleost and that genes involved in mammalian bone differentiation have orthologs in zebrafish. We will also discuss as human diseases, such as osteogenesis imperfecta, osteoarthritis, osteoporosis and Gaucher disease can be investigated in the zebrafish model
Measuring and reducing the impact of the operating system kernel on end-to-end latencies in synchronous packet switched networks
No full textAhab’s legs in scenario-based requirements validation: An experiment to study communication mistakes
No full textThe correct identification of requirements is a crucial step for the implementation of a satisfactory software system. In the validation of \edit{requirements with scenarios}, a straightforward communication is central to obtain a good participation from stakeholders. Technical specifications are translated into scenarios to make them concrete and easy to understand for non-technical users, and contextual details are added to encourage user engagement.
However, additional contextual details (Ahab's Legs) could generate a negative impact on the requirements' validation by leading to proliferating comments that are not pertinent to session objective. The objective of this study is to evaluate the impact of Ahab's Leg to scenario-based requirement validation sessions. We conducted a controlled experiment with human participants and measured the pertinence of the comments formulated by participants when discussing the requirements. The results of our experiment suggest that the potentially negative impact of Ahab's Leg can be effectively controlled by the analyst
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