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result(s) for
"Gutiérrez, Cristina"
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Isotopes reveal contrasting water use strategies among coexisting plant species in a Mediterranean ecosystem
by
José Ignacio Querejeta
,
Todd E. Dawson
,
Emilio Nicolás
in
arid lands
,
Arid zones
,
Biodiversity
2012
Variation in the stable carbon and oxygen isotope composition (δ13C, Δ18O) of co-occurring plant species may reflect the functional diversity of water use strategies present in natural plant communities.
We investigated the patterns of water use among 10 coexisting plant species representing diverse taxonomic groups and life forms in semiarid southeast Spain by measuring their leaf δ13C and Δ18O, the oxygen isotope ratio of stem water and leaf gas exchange rates.
Across species, Δ18O was tightly negatively correlated with stomatal conductance (gs), whereas δ13C was positively correlated with intrinsic water use efficiency (WUEi). Broad interspecific variation in Δ18O, δ13C and WUEi was largely determined by differences in gs, as indicated by a strong positive correlation between leaf δ13C and Δ18O across species
The 10 co-occurring species segregated along a continuous ecophysiological gradient defined by their leaf δ13C and Δ18O, thus revealing a wide spectrum of stomatal regulation intensity and contrasting water use strategies ranging from ‘profligate/opportunistic’ (high gs, low WUEi) to ‘conservative’ (low gs, high WUEi). Coexisting species maintained their relative isotopic rankings in 2 yr with contrasting rainfall, suggesting the existence of species-specific ‘isotopic niches’ that reflect ecophysiological niche segregation in dryland plant communities.
Journal Article
Smart Video Surveillance System Based on Edge Computing
by
Cob-Parro, Antonio Carlos
,
Marrón-Romera, Marta
,
Losada-Gutiérrez, Cristina
in
Algorithms
,
Artificial intelligence
,
Cameras
2021
New processing methods based on artificial intelligence (AI) and deep learning are replacing traditional computer vision algorithms. The more advanced systems can process huge amounts of data in large computing facilities. In contrast, this paper presents a smart video surveillance system executing AI algorithms in low power consumption embedded devices. The computer vision algorithm, typical for surveillance applications, aims to detect, count and track people’s movements in the area. This application requires a distributed smart camera system. The proposed AI application allows detecting people in the surveillance area using a MobileNet-SSD architecture. In addition, using a robust Kalman filter bank, the algorithm can keep track of people in the video also providing people counting information. The detection results are excellent considering the constraints imposed on the process. The selected architecture for the edge node is based on a UpSquared2 device that includes a vision processor unit (VPU) capable of accelerating the AI CNN inference. The results section provides information about the image processing time when multiple video cameras are connected to the same edge node, people detection precision and recall curves, and the energy consumption of the system. The discussion of results shows the usefulness of deploying this smart camera node throughout a distributed surveillance system.
Journal Article
How to select the electronic target for robot trajectory tracking Lyapunov‐based controllers: Comparative study and experimental results
by
Losada‐Gutiérrez, Cristina
,
Espinosa, Felipe
,
Rodríguez‐Ascariz, José M.
in
Case studies
,
Comparative studies
,
computer aided instruction
2023
The proper sizing of the electronic target to implement complex controllers is barely tackled at engineering schools. An incorrect selection leads, at best, to inefficient use of resources and unnecessarily high costs. In this work, the criteria to implement the electronic Lyapunov‐based controller for non‐linear trajectory tracking of a P3‐DX robot is focused on. After comparing pros and cons of the four alternatives, test results are shown with two of them: NUC8i5INH microcomputer and STM32F767 single chip board. In this work, the criteria to implement the electronic Lyapunov‐based controller for non‐linear trajectory tracking of a P3‐DX robot is focused on. Incorrect sizing of the electronic target leads, at best, to inefficient use of resources and unnecessarily high costs.
Journal Article
The Affective Forces of the State: Overcoming Biographies of Violence in Yejide Kilanko’s Daughters Who Walk this Path
2024
This article delves into the abuses stemming from the Nigerian state forces and their failure to protect Nigerian citizens as illustrated in Yejide Kilanko’s Daughters Who Walk this Path (2012). The novel narrates the struggles undergone by young Morayo as she is repeatedly abused as a child by an elder cousin, Bros T. Here, I seek to trace a parallelism between the instances of physical and affective violence against Morayo and the episodes of “intra-societal violence” (Hill 2012: 15) occurring in Nigeria from the 1980s to the mid-1990s, when the country’s sociopolitical sphere was marked by the social chaos resulting from armed robberies, military coups, rigged elections, and instances of police brutality towards women. I shall analyze such episodes as instances of ‘forced intimacy’ within the public and private spheres, which translates into the impositions of negative forms of affect upon personal and collective development. In this context, the physical and psychological abuses suffered by Morayo will be presented as shaping what Ahmed refers to as one’s “biographies of violence” (2017: 23). My ultimate aim is to trace Morayo’s development of what I will describe as ‘affective resilience’ against the affective forces of the state.
Journal Article
3DFCNN: real-time action recognition using 3D deep neural networks with raw depth information
by
de López-Diz, Sergio
,
Losada-Gutiérrez, Cristina
,
Sánchez-Caballero, Adrián
in
Artificial neural networks
,
Computer Communication Networks
,
Computer Science
2022
This work describes an end-to-end approach for real-time human action recognition from raw depth image-sequences. The proposal is based on a 3D fully convolutional neural network, named 3DFCNN, which automatically encodes spatio-temporal patterns from raw depth sequences. The described 3D-CNN allows actions classification from the spatial and temporal encoded information of depth sequences. The use of depth data ensures that action recognition is carried out protecting people’s privacy, since their identities can not be recognized from these data. The proposed 3DFCNN has been optimized to reach a good performance in terms of accuracy while working in real-time. Then, it has been evaluated and compared with other state-of-the-art systems in three widely used public datasets with different characteristics, demonstrating that 3DFCNN outperforms all the non-DNN-based state-of-the-art methods with a maximum accuracy of 83.6% and obtains results that are comparable to the DNN-based approaches, while maintaining a much lower computational cost of 1.09 seconds, what significantly increases its applicability in real-world environments.
Journal Article
Real-time human action recognition using raw depth video-based recurrent neural networks
by
Fuentes-Jiménez, David
,
Sánchez-Caballero, Adrián
,
Losada-Gutiérrez, Cristina
in
Accuracy
,
Human activity recognition
,
Neural networks
2023
This work proposes and compare two different approaches for real-time human action recognition (HAR) from raw depth video sequences. Both proposals are based on the convolutional long short-term memory unit, namely ConvLSTM, with differences in the architecture and the long-term learning. The former uses a video-length adaptive input data generator (stateless) whereas the latter explores the stateful ability of general recurrent neural networks but is applied in the particular case of HAR. This stateful property allows the model to accumulate discriminative patterns from previous frames without compromising computer memory. Furthermore, since the proposal uses only depth information, HAR is carried out preserving the privacy of people in the scene, since their identities can not be recognized. Both neural networks have been trained and tested using the large-scale NTU RGB+D dataset. Experimental results show that the proposed models achieve competitive recognition accuracies with lower computational cost compared with state-of-the-art methods and prove that, in the particular case of videos, the rarely-used stateful mode of recurrent neural networks significantly improves the accuracy obtained with the standard mode. The recognition accuracies obtained are 75.26% (CS) and 75.45% (CV) for the stateless model, with an average time consumption per video of 0.21 s, and 80.43% (CS) and 79.91%(CV) with 0.89 s for the stateful one.
Journal Article
Association between Oral Cancer and Diet: An Update
by
Martín Carreras-Presas, Carmen
,
Rodríguez-Molinero, Jesús
,
Puente-Gutiérrez, Cristina
in
alcohols
,
antioxidants
,
complement
2021
Oral cancer, included within head and neck cancer, is the sixth most common malignant neoplasm in the world. The main etiological factors are tobacco and alcohol, although currently, diet is considered an important determinant for its development. Several dietary nutrients have specific mechanisms of action, contributing to both protection against cancer and increasing the risk for development, growth, and spread. Foods such as fruits, vegetables, curcumin, and green tea can reduce the risk of oral cancer, while the so-called pro-inflammatory diet, rich in red meat and fried foods, can enhance the risk of occurrence. Dietary factors with a protective effect show different mechanisms that complement and overlap with antioxidant, anti-inflammatory, anti-angiogenic, and anti-proliferative effects. The main limitation of in vivo studies is the complexity of isolating the effects related to each one of the nutrients and the relationship with other possible etiological mechanisms. On the contrary, in vitro studies allow determining the specific mechanisms of action of some of the dietary compounds. In conclusion, and despite research limitations, the beneficial effects of a diet rich in vegetables and fruits are attributed to different micronutrients that are also found in fish and animal products. These compounds show antioxidant, anti-inflammatory, anti-angiogenic, and anti-proliferative properties that have a preventive role in the development of oral and other types of cancer.
Journal Article
The cohesin subunit RAD21L functions in meiotic synapsis and exhibits sexual dimorphism in fertility
2011
The cohesin complex is a ring‐shaped proteinaceous structure that entraps the two sister chromatids after replication until the onset of anaphase when the ring is opened by proteolytic cleavage of its α‐kleisin subunit (RAD21 at mitosis and REC8 at meiosis) by separase. RAD21L is a recently identified α‐kleisin that is present from fish to mammals and biochemically interacts with the cohesin subunits SMC1, SMC3 and STAG3. RAD21L localizes along the axial elements of the synaptonemal complex of mouse meiocytes. However, its existence as a bona fide cohesin and its functional role awaits
in vivo
validation. Here, we show that male mice lacking RAD21L are defective in full synapsis of homologous chromosomes at meiotic prophase I, which provokes an arrest at zygotene and leads to total azoospermia and consequently infertility. In contrast, RAD21L‐deficient females are fertile but develop an age‐dependent sterility. Thus, our results provide
in vivo
evidence that RAD21L is essential for male fertility and in females for the maintenance of fertility during natural aging.
The first mouse knockout analysis of RAD21L, only recently identified as a meiosis‐specific cohesin subunit in vertebrates, reveals its importance in germ cell formation—with unexpected sex‐specific differential requirements.
Journal Article
A Predator–Prey Two-Sex Branching Process
by
Minuesa, Carmen
,
Gutiérrez, Cristina
in
Branching (mathematics)
,
coexistence
,
controlled two-sex branching process
2020
In this paper, we present the first stochastic process to describe the interaction of predator and prey populations with sexual reproduction. Specifically, we introduce a two-type two-sex controlled branching model. This process is a two-type branching process, where the first type corresponds to the predator population and the second one to the prey population. While each population is described via a two-sex branching model, the interaction and survival of both groups is modelled through control functions depending on the current number of individuals of each type in the ecosystem. In view of their potential for the conservation of species, we provide necessary and sufficient conditions for the ultimate extinction of both species, the fixation of one of them and the coexistence of both of them. Moreover, the description of the present predator–prey two-sex branching process on the fixation events can be performed in terms of the behaviour of a one-type two-sex branching process with a random control on the number of individuals, which is also introduced and analysed.
Journal Article
Resistance of the cold-water coral Dendrophyllia cornigera to single and combined global change stressors
2025
Current knowledge of the consequences on global change in deep marine ecosystems is still limited, especially since environmental pressures do not act separately, and their potential interactions are mostly unknown. Cold-water corals (CWC) play a significant role in the deep sea, being ecosystem engineers supporting high biodiversity. However, global change may impact CWCs, compromising their integrity and survival. In this study, a nine-month aquaria experiment was conducted on the CWC
Dendrophyllia cornigera
from the NW Iberian Shelf (NE Atlantic Ocean). The aim was to assess the individual and combined effects of elevated temperature (12 vs. 15 °C), low pH (~ 7.99 vs. 7.69 pH
T
) and low oxygen (~ 6.4 vs. 4.7 mL L
−1
), based on the IPCC RCP 8.5 scenario. During the experiment, coral survival, skeletal growth, tissue cover and respiration were monitored as response variables. No significant effects were found on any of the response variables for either individual or combined stressors, pointing to the resistance of
D. cornigera
to different global change scenarios. Such a physiological resistance may support
D. cornigera
persistence under future conditions where other CWCs with narrower tolerance ranges may face greater limitations. However, further research is needed to assess potential trade-offs to cope with environmental change, which might impact the long-term survival capacity of this species.
Journal Article