Determination of nutrient salts by automatic methods both in seawater and brackish water: the phosphate blank

9 páginas, 2 tablas, 2 figurasThe main inconvenience in determining nutrients in seawater by automatic methods is simply solved: the preparation of a suitable blank which corrects the effect of the refractive index change on the recorded signal. Two procedures are proposed, one physical (a simple equation to estimate the effect) and the other chemical (removal of the dissolved phosphorus with ferric hydroxide).Support for this work came from CICYT (MAR88-0245 project) and Conselleria de Pesca de la Xunta de GaliciaPeer reviewe

What's Old and New? Discovering Topics in the American Journal of Sociology

Nowadays the field of text mining techniques seems to be very active in dealing with the increasing mass of available digital texts and several algorithms have been proposed to analyze and synthesize the vast amount of data that today represents a challenging source of information overload. Topic modeling is a collection of algorithms which are useful for discovering themes, i.e. topics, in unstructured text. The Latent Dirichlet Allocation (LDA) by Blei (et al., 2003) was one of the first topic modeling algorithms and since then the field seems to be active and many variants and other algorithms have been suggested. The present study considers a topic as an indicator of the relevance of a research area in a specific time-span and its temporal evolution pattern as a way to identify the paradigm changes in terms of theories, ideas, forgotten topics, evergreen subjects and new emerging research interests. The study aims to contribute to a substantive reflection in Sociology by exploring the temporal evolution of topics in the abstracts of articles published by the American Journal of Sociology in the last century (1921-2016). Within the classical LDA perspective, the study also focus on topics with a significant increasing or decreasing trend (Griffiths et Steyvers, 2004). The results show different shifts that involved relevant reflections on various issues, from the early debate on the \u201cinstitutionalization\u201d process of Sociology as a scientific discipline to recent developments of sociological topics that clearly indicate how sociologists have reacted to new social problem

Empowering University Educators for Contemporary Open and Networked Teaching

The chapter explores the competences that university educators should master in our increasingly digital, open and connected societies in order to fill their role effectively and responsibly. Starting from a brief analysis of the concepts of collaborative learning and open education, we analyse three teachers’ competencies frameworks, focusing on the digital, collaboration and openness aspects of contemporary teaching. We conclude that educators should not build radically new competences but should rather update their competences in line with emerging needs. Also, we notice that some additional competence areas should be developed by educators, if we want them to be able to bridge the work of students in formal and informal settings. We propose six competences areas in this sense: personal data management, capacity to leverage the open web, intercultural digital dialogues, critical view on media, digital ethical issues, accessibility. These areas are becoming increasingly important for educators to be able to critically engage learners in the core issues of our digital, networked and open societies, guiding them—in open and collaborative ways—towards solutions to the newly emerging problems of our times

Prodromal Transient Ischemic Attack or Minor Stroke and Outcome in Basilar Artery Occlusion

Background The presence of prodromal transient ischemic attacks (TIAs) has been associated with a favorable outcome in anterior circulation stroke. We aimed to determine the association between prodromal TIAs or minor stroke and outcomes at 1 month, in the Basilar Artery International Cooperation Study, a registry of patients presenting with an acute symptomatic and radiologically confirmed basilar artery occlusion. Methods A total of 619 patients were enrolled in the registry. Information on prodromal TIAs was available for 517 patients and on prodromal stroke for 487 patients. We calculated risk ratios and corresponding 95% confidence intervals (CIs) for poor clinical outcome (modified Rankin Scale score <4) according to the variables of interest. Results Prodromal minor stroke was associated with poor outcome (crude risk ratio [cRR], 1.26; 95% CI, 1.12-1.42), but TIAs were not (cRR,.93; 95% CI,.79-1.09). These associations remained essentially the same after adjustment for confounding variables. Conclusions Prodromal minor stroke was associated with an unfavorable outcome in patients with basilar artery occlusion, whereas prodromal TIA was not

Treatment and outcomes of acute basilar artery occlusion in the Basilar Artery International Cooperation Study (BASICS) : a prospective registry study

BACKGROUND: Treatment strategies for acute basilar artery occlusion (BAO) are based on case series and data that have been extrapolated from stroke intervention trials in other cerebrovascular territories, and information on the efficacy of different treatments in unselected patients with BAO is scarce. We therefore assessed outcomes and differences in treatment response after BAO. METHODS: The Basilar Artery International Cooperation Study (BASICS) is a prospective, observational registry of consecutive patients who presented with an acute symptomatic and radiologically confirmed BAO between November 1, 2002, and October 1, 2007. Stroke severity at time of treatment was dichotomised as severe (coma, locked-in state, or tetraplegia) or mild to moderate (any deficit that was less than severe). Outcome was assessed at 1 month. Poor outcome was defined as a modified Rankin scale score of 4 or 5, or death. Patients were divided into three groups according to the treatment they received: antithrombotic treatment only (AT), which comprised antiplatelet drugs or systemic anticoagulation; primary intravenous thrombolysis (IVT), including subsequent intra-arterial thrombolysis; or intra-arterial therapy (IAT), which comprised thrombolysis, mechanical thrombectomy, stenting, or a combination of these approaches. Risk ratios (RR) for treatment effects were adjusted for age, the severity of neurological deficits at the time of treatment, time to treatment, prodromal minor stroke, location of the occlusion, and diabetes. FINDINGS: 619 patients were entered in the registry. 27 patients were excluded from the analyses because they did not receive AT, IVT, or IAT, and all had a poor outcome. Of the 592 patients who were analysed, 183 were treated with only AT, 121 with IVT, and 288 with IAT. Overall, 402 (68%) of the analysed patients had a poor outcome. No statistically significant superiority was found for any treatment strategy. Compared with outcome after AT, patients with a mild-to-moderate deficit (n=245) had about the same risk of poor outcome after IVT (adjusted RR 0.94, 95% CI 0.60-1.45) or after IAT (adjusted RR 1.29, 0.97-1.72) but had a worse outcome after IAT compared with IVT (adjusted RR 1.49, 1.00-2.23). Compared with AT, patients with a severe deficit (n=347) had a lower risk of poor outcome after IVT (adjusted RR 0.88, 0.76-1.01) or IAT (adjusted RR 0.94, 0.86-1.02), whereas outcomes were similar after treatment with IAT or IVT (adjusted RR 1.06, 0.91-1.22). INTERPRETATION: Most patients in the BASICS registry received IAT. Our results do not support unequivocal superiority of IAT over IVT, and the efficacy of IAT versus IVT in patients with an acute BAO needs to be assessed in a randomised controlled trial. FUNDING: Department of Neurology, University Medical Center Utrecht

Predicting outcome after acute basilar artery occlusion based on admission characteristics.

OBJECTIVE: To develop a simple prognostic model to predict outcome at 1 month after acute basilar artery occlusion (BAO) with readily available predictors. METHODS: The Basilar Artery International Cooperation Study (BASICS) is a prospective, observational, international registry of consecutive patients who presented with an acute symptomatic and radiologically confirmed BAO. We considered predictors available at hospital admission in multivariable logistic regression models to predict poor outcome (modified Rankin Scale [mRS] score 4-5 or death) at 1 month. We used receiver operator characteristic curves to assess the discriminatory performance of the models. RESULTS: Of the 619 patients, 429 (69%) had a poor outcome at 1 month: 74 (12%) had a mRS score of 4, 115 (19%) had a mRS score of 5, and 240 (39%) had died. The main predictors of poor outcome were older age, absence of hyperlipidemia, presence of prodromal minor stroke, higher NIH Stroke Scale (NIHSS) score, and longer time to treatment. A prognostic model that combined demographic data and stroke risk factors had an area under the receiver operating characteristic curve (AUC) of 0.64. This performance improved by including findings from the neurologic examination (AUC 0.79) and CT imaging (AUC 0.80). A risk chart showed predictions of poor outcome at 1 month varying from 25 to 96%. CONCLUSION: Poor outcome after BAO can be reliably predicted by a simple model that includes older age, absence of hyperlipidemia, presence of prodromal minor stroke, higher NIHSS score, and longer time to treatment