12 research outputs found
Analysis on morphodynamics and evolution of bed forms in the Orinoco River
The Orinoco River is the third largest flow-discharge river in the world with an average water flow of 37,600 m3s-1. Due to the presence of the Guyana shield on the right bank, the lower reach of the Orinoco presents a plan form characterized by alternance of contraction and expansion zones (Laraque et al., 2013). Typical 1-1.5 km width narrow reaches are followed by 7-8 km wide reaches (Figure 1). A complex pattern of bed aggradation and degradation processes takes place during the hydrological cycle. The relationship between
flow velocity and morphodynamic of sand waves and bars in an expansion/contraction channel is very important to understand the processes that control the evolution of rivers. Considerable research efforts has recently been directed towards the understanding of
fluvial processes associated with geomorphology and hydrologic conditions with the river width, which are explained through the mechanics of formation and evolution of sand waves and bars
Risk factors associated with adverse fetal outcomes in pregnancies affected by Coronavirus disease 2019 (COVID-19): a secondary analysis of the WAPM study on COVID-19.
Objectives To evaluate the strength of association between maternal and pregnancy characteristics and the risk of adverse perinatal outcomes in pregnancies with laboratory confirmed COVID-19. Methods Secondary analysis of a multinational, cohort study on all consecutive pregnant women with laboratory-confirmed COVID-19 from February 1, 2020 to April 30, 2020 from 73 centers from 22 different countries. A confirmed case of COVID-19 was defined as a positive result on real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay of nasal and pharyngeal swab specimens. The primary outcome was a composite adverse fetal outcome, defined as the presence of either abortion (pregnancy loss before 22 weeks of gestations), stillbirth (intrauterine fetal death after 22 weeks of gestation), neonatal death (death of a live-born infant within the first 28 days of life), and perinatal death (either stillbirth or neonatal death). Logistic regression analysis was performed to evaluate parameters independently associated with the primary outcome. Logistic regression was reported as odds ratio (OR) with 95% confidence interval (CI). Results Mean gestational age at diagnosis was 30.6+/-9.5 weeks, with 8.0% of women being diagnosed in the first, 22.2% in the second and 69.8% in the third trimester of pregnancy. There were six miscarriage (2.3%), six intrauterine device (IUD) (2.3) and 5 (2.0%) neonatal deaths, with an overall rate of perinatal death of 4.2% (11/265), thus resulting into 17 cases experiencing and 226 not experiencing composite adverse fetal outcome. Neither stillbirths nor neonatal deaths had congenital anomalies found at antenatal or postnatal evaluation. Furthermore, none of the cases experiencing IUD had signs of impending demise at arterial or venous Doppler. Neonatal deaths were all considered as prematurity-related adverse events. Of the 250 live-born neonates, one (0.4%) was found positive at RT-PCR pharyngeal swabs performed after delivery. The mother was tested positive during the third trimester of pregnancy. The newborn was asymptomatic and had negative RT-PCR test after 14 days of life. At logistic regression analysis, gestational age at diagnosis (OR: 0.85, 95% CI 0.8-0.9 per week increase; pPeer reviewe
The Rule of 10: a simple 3D ultrasonographic method for the diagnosis of T-shaped uterus
Purpose To investigate and propose a new simple tridimensional (3D) ultrasonographic method to diagnose a T-shaped uterus (Class U1a). Methods A multicenter non-experimental case-control diagnostic accuracy study was conducted between January 2018 and December 2019, including 50 women (cases) diagnosed with T-shaped uterus (U1a class) and 50 women with a "normal uterus" (controls). All the enrolled women underwent 3D ultrasound, drawing four lines and recording the length of three of them as follow: draw and measure the interostial line (R0); draw from the midpoint of R0 a perpendicular line length 20 mm; draw and measure in the uterine cavity a line parallel to R0 at 10 mm below R0 (R10) and a second line parallel to R0 at 20 mm below R0 (R20). The diagnostic performance of all sonographic parameters statistically significantly different between T-shaped and normal uteri was estimated using the receiver operator characteristic (ROC) curve analysis. Results R10 and R20 were statistically significantly shorter in the T-shaped than the normal uterus. R10 reported the highest diagnostic accuracy with an area under the ROC curve of 0.973 (95% CI 0.940-1.000). R10 length maximizing the Youden's J statistic was 10.5 mm. Assuming R10 length equal to or shorter than 10 mm as the cut off value for defining a woman as having a T-shaped uterus, the new ultrasonographic method following the proposed protocol (R0, R10, and R20) reported sensitivity for T-shaped uterus of 91.1% (95% CI 0.78-0.97%) and a specificity of 100% (95% CI 0.89-100%). The positive likelihood ratio was higher than 30, and the negative likelihood ratio was 0.09 (95% CI 0.04-0.26). Conclusions Measuring the length of the intracavitary line parallel to the interostial line at 10 mm from it and using a length <= of 10 mm as cut off value (the "Rule of 10") appears a simple and accurate 3D ultrasonographic method for the diagnosis of a T-shaped uterus
Product Market Frictions, Bargaining and Pass-Through Product market frictions, bargaining and pass-through
ABSTRACT Empirical evidence shows that the pass-through of cost shocks to prices is very low, and delayed. This is in stark contrast with the standard framework of monopolistic competition used in macro models, which, absent nominal rigidities, implies complete pass-through of cost shocks to prices. This paper develops a model of pricing dynamics in business to business relationships where incomplete pass-through arises endogenously. The model is based on two assumptions. First, both retailers and wholesalers invest resources to form new, long-term, business relationships. Second, once a business relationship is formed, the prices and the quantities of the intermediate good exchanged are set in a bilateral bargaining between wholesalers and retailers. The repeated nature of the interactions between firms raises the question of whether wholesale prices are allocative. We show that wholesale prices still play an allocative role in the model, but this role is likely to be quite limited. Abstract Empirical evidence shows that the pass-through of cost shocks to prices is very low, and delayed. This is in stark contrast with the standard framework of monopolistic competition used in macro models, which, absent nominal rigidities, implies complete pass-through of cost shocks to prices. This paper develops a model of pricing dynamics in business to business relationships where incomplete pass-through arises endogenously. The model is based on two assumptions. First, both retailers and wholesalers invest resources to form new, long-term, business relationships. Second, once a business relationship is formed, the prices and the quantities of the intermediate good exchanged are set in a bilateral bargaining between wholesalers and retailers. The repeated nature of the interactions between …rms raises the question of whether wholesale prices are allocative. We show that wholesale prices still play an allocative role in the model, but this role is likely to be quite limited. JEL classi…cation: E10, E3
Functional recovery of secondary tropical forests
One-third of all Neotropical forests are secondary forests that regrow naturally after agricultural use through secondary succession. We need to understand better how and why succession varies across environmental gradients and broad geographic scales. Here, we analyze functional recovery using community data on seven plant characteristics (traits) of 1,016 forest plots from 30 chronosequence sites across the Neotropics. By analyzing communities in terms of their traits, we enhance understanding of the mechanisms of succession, assess ecosystem recovery, and use these insights to propose successful forest restoration strategies. Wet and dry forests diverged markedly for several traits that increase growth rate in wet forests but come at the expense of reduced drought tolerance, delay, or avoidance, which is important in seasonally dry forests. Dry and wet forests showed different successional pathways for several traits. In dry forests, species turnover is driven by drought tolerance traits that are important early in succession and in wet forests by shade tolerance traits that are important later in succession. In both forests, deciduous and compound-leaved trees decreased with forest age, probably because microclimatic conditions became less hot and dry. Our results suggest that climatic water availability drives functional recovery by influencing the start and trajectory of succession, resulting in a convergence of community trait values with forest age when vegetation cover builds up. Within plots, the range in functional trait values increased with age. Based on the observed successional trait changes, we indicate the consequences for carbon and nutrient cycling and propose an ecologically sound strategy to improve forest restoration success
Functional recovery of secondary tropical forests
One-third of all Neotropical forests are secondary forests that regrow naturally after agricultural use through secondary succession. We need to understand better how and why succession varies across environmental gradients and broad geographic scales. Here we present data on functional recovery, using community data on seven plant characteristics (traits) of 1016 forest plots from 30 chronosequence sites across the Neotropics. By analyzing communities in terms of their traits one can enhance understanding of the mechanisms of succession and assess ecosystem recovery
Paisaje Cultural Urbano e Identitad Territorial
Linguaggio contemporaneo e preesistenze: dialogo in un mondo globalizzato
Il tema del rapporto con l’antico trova una giusta dimensione operativa quando, superando la sfera delle ideologie e quella delle opposte ragioni della memoria e dello sviluppo, indirizza positivamente l’azione progettuale ora per differenza ora per empatia, a seconda delle circostanze, ma crea sempre una forte tensione tra le ragioni dell’esistente e le necessità del nuovo. Intervenire nell’antico e per l’antico significa, pertanto, riprogettare il nostro modo di relazionarci con il passato, rinegoziandone identità e valori alla luce del nostro presente. Da questa angolazione il patrimonio non è solo lo spazio della memoria o quello della storia, ma diviene lo spazio del desiderio che trae alimento dal mito dell’araba fenice: esso, come principio evolutivo, rappresenta l’inizio di un incessante ricominciamento e l'occasione per una mediazione tra globale e locale
Treatments for intracranial hypertension in acute brain-injured patients: grading, timing, and association with outcome. Data from the SYNAPSE-ICU study
Purpose: Uncertainties remain about the safety and efficacy of therapies for managing intracranial hypertension in acute brain injured (ABI) patients. This study aims to describe the therapeutical approaches used in ABI, with/without intracranial pressure (ICP) monitoring, among different pathologies and across different countries, and their association with six months mortality and neurological outcome. Methods: A preplanned subanalysis of the SYNAPSE-ICU study, a multicentre, prospective, international, observational cohort study, describing the ICP treatment, graded according to Therapy Intensity Level (TIL) scale, in patients with ABI during the first week of intensive care unit (ICU) admission. Results: 2320 patients were included in the analysis. The median age was 55 (I-III quartiles = 39-69) years, and 800 (34.5%) were female. During the first week from ICU admission, no-basic TIL was used in 382 (16.5%) patients, mild-moderate in 1643 (70.8%), and extreme in 295 cases (eTIL, 12.7%). Patients who received eTIL were younger (median age 49 (I-III quartiles = 35-62) vs 56 (40-69) years, p < 0.001), with less cardiovascular pre-injury comorbidities (859 (44%) vs 90 (31.4%), p < 0.001), with more episodes of neuroworsening (160 (56.1%) vs 653 (33.3%), p < 0.001), and were more frequently monitored with an ICP device (221 (74.9%) vs 1037 (51.2%), p < 0.001). Considerable variability in the frequency of use and type of eTIL adopted was observed between centres and countries. At six months, patients who received no-basic TIL had an increased risk of mortality (Hazard ratio, HR = 1.612, 95% Confidence Interval, CI = 1.243-2.091, p < 0.001) compared to patients who received eTIL. No difference was observed when comparing mild-moderate TIL with eTIL (HR = 1.017, 95% CI = 0.823-1.257, p = 0.873). No significant association between the use of TIL and neurological outcome was observed. Conclusions: During the first week of ICU admission, therapies to control high ICP are frequently used, especially mild-moderate TIL. In selected patients, the use of aggressive strategies can have a beneficial effect on six months mortality but not on neurological outcome
Maternal and Perinatal Outcomes of Pregnant Women with SARS-COV-2 infection
To evaluate maternal and perinatal outcomes of pregnant women affected by SARS-COV-2