Search results for "Bottom-Up"

Response of seagrasses and marine biofilms to natural acidification at CO2 vents

Nel corso degli ultimi 200 anni, circa il 30% delle emissioni antropogeniche di CO2 nell’atmosfera sono state assorbite dagli oceani, provocando un abbassamento medio dei livelli di pH oceanici pari a circa 0.1 unità. Questo fenomeno, noto come acidificazione degli oceani, sta determinando conseguenze negative sugli ecosistemi marini e sul loro funzionamento. Le attuali proiezioni climatiche suggeriscono che, in futuro, i cambiamenti climatici continueranno e si intensificheranno se non verranno adottate efficaci misure di mitigazione. Riuscire a valutare la risposta degli ecosistemi marini ai cambiamenti climatici costituisce una vera sfida per la ricerca scientifica, non solo per la diffi…

Constrained Role Mining

2013

Role Based Access Control (RBAC) is a very popular access control model, for long time investigated and widely deployed in the security architecture of different enterprises. To implement RBAC, roles have to be firstly identified within the considered organization. Usually the process of (automatically) defining the roles in a bottom up way, starting from the permissions assigned to each user, is called {\it role mining}. In literature, the role mining problem has been formally analyzed and several techniques have been proposed in order to obtain a set of valid roles. Recently, the problem of defining different kind of constraints on the number and the size of the roles included in the resu…

Label-Free Proteomics of Quantity-Limited Samples Using Ion Mobility-Assisted Data-Independent Acquisition Mass Spectrometry

2021

Over the past two decades, unbiased data-independent acquisition (DIA) approaches have gained increasing popularity in the bottom-up proteomics field. Here, we describe an ion mobility separation enhanced DIA workflow for large-scale label-free quantitative proteomics studies where starting material is limited. We set a special focus on the single pot solid-phase-enhanced sample preparation (SP3) protocol, which is well suited for the processing of quantity-limited samples.

Fish introductions and light modulate food web fluxes in tropical streams : a whole-ecosystem experimental approach

2016

Decades of ecological study have demonstrated the importance of top-down and bottom-up controls on food webs, yet few studies within this context have quantified the magnitude of energy and material fluxes at the whole-ecosystem scale. We examined top-down and bottom-up effects on food web fluxes using a field experiment that manipulated the presence of a consumer, the Trinidadian guppy Poecilia reticulata, and the production of basal resources by thinning the riparian forest canopy to increase incident light. To gauge the effects of these reach-scale manipulations on food web fluxes, we used a nitrogen (15N) stable isotope tracer to compare basal resource treatments (thinned canopy vs. con…

Inovācijas universitātē: varas un leģitimitātes aspekti

2014

Anotācija Promocijas darba mērķis ir analizēt augšupvērstas inovācijas universitātē, tās specifiskajā strukturālās varas, profesionālās autonomijas un profesionālo prakses kopienu kontekstā. Pētījums veikts izmantojot konstrukcionisma pieeju datos pamatotās vidēja līmeņa teorijas izveidei. Teorētiskie jēdzieni aizgūti no situatīvās mācīšanās teorijas, papildinātas ar mikro-institucionālisma pieeju un varas konceptualizācijām. Veikta 30 mikro-gadījumu analīze divās Latvijas universitātēs. Pētījumā raksturota augšupvērstu inovāciju daudzveidība, izveidoti trīs inovāciju virzīšanas modeļi, identificēta to iznākumu ietekme uz inovācijas rosinātāju identitāti un piederību. Autore saista šos rezu…

The Timecourse of Sentence Processing in the Brain

2015

This chapter discusses the current state of the art with regard to the timecourse of sentence processing in the brain. It outlines the challenges associated with studying timecourse information at the sentence level from a neurobiological perspective and describes competing theoretical and empirical perspectives in this domain. In addition to drawing on findings from neurophysiological methods (electroencephalography [EEG]; magnetoencephalography [MEG]), insights from eye movement measures during natural reading are also taken into account. The chapter concludes that while we are currently unable to make absolute claims about the timecourse of sentence processing from a neurobiological pers…

On parsing optimality for dictionary-based text compression—the Zip case

2013

Dictionary-based compression schemes are the most commonly used data compression schemes since they appeared in the foundational paper of Ziv and Lempel in 1977, and generally referred to as LZ77. Their work is the base of Zip, gZip, 7-Zip and many other compression software utilities. Some of these compression schemes use variants of the greedy approach to parse the text into dictionary phrases; others have left the greedy approach to improve the compression ratio. Recently, two bit-optimal parsing algorithms have been presented filling the gap between theory and best practice. We present a survey on the parsing problem for dictionary-based text compression, identifying noticeable results …

Combining Top-down and Bottom-up Visual Saliency for Firearms Localization

2014

Object detection is one of the most challenging issues for computer vision researchers. The analysis of the human visual attention mechanisms can help automatic inspection systems, in order to discard useless information and improving performances and efficiency. In this paper we proposed our attention based method to estimate firearms position in images of people holding firearms. Both top-down and bottom-up mechanisms are involved in our system. The bottom-up analysis is based on a state-of-the-art approach. The top-down analysis is based on the construction of a probabilistic model of the firearms position with respect to the people’s face position. This model has been created by analyzi…

The Role of Mathematical Models in Immuno-Oncology: Challenges and Future Perspectives

2021

Immuno-oncology (IO) focuses on the ability of the immune system to detect and eliminate cancer cells. Since the approval of the first immune checkpoint inhibitor, immunotherapies have become a major player in oncology treatment and, in 2021, represented the highest number of approved drugs in the field. In spite of this, there is still a fraction of patients that do not respond to these therapies and develop resistance mechanisms. In this sense, mathematical models offer an opportunity to identify predictive biomarkers, optimal dosing schedules and rational combinations to maximize clinical response. This work aims to outline the main therapeutic targets in IO and to provide a description …

From top-down urban planning to culturally sensitive planning? Urban renewal and artistic activism in a neo-bohemian district in Barcelona

2020

The city of Barcelona in general and its historic center in particular have undergone a sea change from an industrial city to a global tourism and service center. Some authors argue that urban rene...