Islands at Risk - Analyzing Resource-use Dynamics from a Socio-metabolic Research Perspective

Our resource-use dynamics have contributed significantly to the improvement in global material standards of living through the provisioning of essential societal services. Nonetheless, these dynamics have also impacted on the already limited natural resource-base of the Earth system on which we depend. Moreover, the characteristics of a global self-perpetuating resource-use linearity, the growing demand for finite raw materials, the high waste generation that remains unrecovered, and the increasing negative effects of climate change further exacerbate the Earth system’s vulnerabilities and exposure to risks. As such, the resource-use dynamics is posited as an important example of complex systems in need for better understanding, particularly in advancing towards sustainability and build system’s resilience. For resource-stressed settings like small island nations, the analysis of these complex systems is not only crucial, but urgent. Small Island Developing States are often characterized by sustainability challenges like limited resource-bases, reduced waste absorption capacity, a strong dependency on external resources to meet their basic needs, geographic isolation from markets which impact connectivity and resource supply, and natural and built environment that is progressively been threatened by the negative effects of climate change, which amplify the pre-existing vulnerabilities and risks for these territories. Thus, dealing with sustainability would require a deeper understanding of the interactions and trade-offs between the resource-use dynamics and the influences that internal/external factors like climate change have over these. By doing so, the system will have the ability to both contribute to global environment change, but also determine their own vulnerability or resilience to those changes. This thesis analyzes resource-use dynamics from a socio-metabolic research perspective in the context of small islands to enhance resource security and build system’s resilience, by looking into the way in which natural resources are interconnected, influenced, and managed. The analysis is spread across three main empirical Chapters, each of which contribute to advancing the arguments that arise from this work. First, in Chapter 3, the thesis analyzes the shifting resource-baselines of water, energy, and food, emphasizing the intra- and interconnected nature between essential resources and socio-metabolic risk, which builds the foundations for deeper analysis on current and future sustainability in small islands. Then, in Chapter 4, the thesis analyzes and identifies the size and make-up of material and energy flows specific to an individual case study, bringing important quantitative and qualitative insights on the potentials that reconfigured resource-use patterns may offer to minimizing or reducing socio-metabolic risk in small islands. Next, in Chapter 5, the thesis analyzes the role that critical material stocks play in driving resource-use and in furthering sustainable development, emphasizing climate change adaptation strategies to build system’s resilience. The overall framework of this thesis has demonstrated how a better understanding of resource-use dynamics may offer an opportunity to achieve resource security and self-reliance as a resilience building measure in the island context. Finally, this thesis encourages for the development and application of holistic and long-term resource management strategies through inclusive, climate and nature-based solutions that consider the trade-offs and synergies between different resource-use dynamics

Association of chronic obstructive pulmonary disease and obstructive sleep apnea consequences

Obstructive sleep apnea syndrome (OSAS) and chronic obstructive pulmonary disease (COPD) are two diseases that often coexist within an individual. This coexistence is known as overlap syndrome and is the result of chance rather than a pathophysiological link. Although there are claims of a very high incidence of OSAS in COPD patients, recent studies report that it is similar to the general population. Overlap patients present sleep-disordered breathing associated to upper and lower airway obstruction and a reduction in respiratory drive. These patients present unique characteristics, which set them apart from either COPD or OSAS patients. COPD and OSAS are independent risk factors for cardiovascular events and their coexistence in overlap syndrome probably increases this risk. The mechanisms underlying cardiovascular risk are still unclear, but may involve systemic inflammation, endothelial dysfunction, and tonic elevation of sympathetic neural activity. The treatment of choice for overlap syndrome in stable patients is CPAP with supplemental oxygen for correction of upper airway obstructive episodes and hypoxemia during sleep

Simulation and Thermo-Energy Analysis of Building Types in the Dominican Republic to Evaluate and Introduce Energy Efficiency in the Envelope

The improvement of the energy performance in buildings is key for sustainable development, even more so in the case of the Dominican Republic (DR), which is committed to this goal but which has neither regulation nor specific social behavior in this field. The main goal of this work is double; on one hand it is aimed at providing useable information for those who have the responsibly of making regulation norms and on the other, it is desirable to give an essential, technically proven and handy tool to those involved in the construction sector in improving the envelopes of buildings and to introduce good practices into the management of the energy systems of buildings. A case study of eight administrative buildings located in different climatic zones of the DR was carried out. A simulation tool was used for the study, and one of the buildings was monitored to verify the simulation work. Those factors that affect the development of the buildings in relation to thermo-energy consumption have been detailed. The large-scale heat gains resulting from the common glazing used by the tertiary sector in the Dominican Republic (including office buildings, hospitals and shops among others) illustrate the need for economically viable solutions in this sector. As a conclusion, it has been proved that the incidental thermal load of buildings could be reduced by up to 40%, thus in turn reducing the costs associated with the electricity needed to maintain the users’ desired thermal comfort level, as their influence in this sector is significant

Wavelet analysis of overnight airflow to detect obstructive sleep apnea in children

Producción CientíficaThis study focused on the automatic analysis of the airflow signal (AF) to aid in the diagnosis of pediatric obstructive sleep apnea (OSA). Thus, our aims were: (i) to characterize the overnight AF characteristics using discrete wavelet transform (DWT) approach, (ii) to evaluate its diagnostic utility, and (iii) to assess its complementarity with the 3% oxygen desaturation index (ODI3). In order to reach these goals, we analyzed 946 overnight pediatric AF recordings in three stages: (i) DWT-derived feature extraction, (ii) feature selection, and (iii) pattern recognition. AF recordings from OSA patients showed both lower detail coefficients and decreased activity associated with the normal breathing band. Wavelet analysis also revealed that OSA disturbed the frequency and energy distribution of the AF signal, increasing its irregularity. Moreover, the information obtained from the wavelet analysis was complementary to ODI3. In this regard, the combination of both wavelet information and ODI3 achieved high diagnostic accuracy using the common OSA-positive cutoffs: 77.97%, 81.91%, and 90.99% (AdaBoost.M2), and 81.96%, 82.14%, and 90.69% (Bayesian multi-layer perceptron) for 1, 5, and 10 apneic events/hour, respectively. Hence, these findings suggest that DWT properly characterizes OSA-related severity as embedded in nocturnal AF, and could simplify the diagnosis of pediatric OSA.Ministerio de Ciencia, Innovación y Universidades, Agencia Estatal de Investigación y Fondo Europeo de Desarrollo Regional (FEDER) - (Projects DPI2017-84280-R and RTC-2017-6516-1)Comisión Europea y Fondo Europeo de Desarrollo Regional (FEDER) - (POCTEP 0702_MIGRAINEE_2_E)Instituto de Salud Carlos III y Fondo Europeo de Desarrollo Regional (FEDER) - (CIBER-BBN)Ministerio de Ciencia e Innovación, Agencia Estatal de Investigación y Fondo Social Europeo - (grant RYC2019- 028566-I)Ministerio de Educación, Cultura y Deporte - (grant FPU16/02938)Institutes of Health - (grants HL130984, HL140548, and AG061824

Symbolic dynamics to enhance diagnostic ability of portable oximetry from the Phone Oximeter in the detection of paediatric sleep apnoea

Objective: This study is aimed at assessing symbolic dynamics as a reliable technique to characterize complex fluctuations of portable oximetry in the context of automated detection of childhood obstructive sleep apnoea-hypopnoea syndrome (OSAHS). Approach: Nocturnal oximetry signals from 142 children with suspected OSAHS were acquired using the Phone Oximeter: a portable device that integrates a pulse oximeter with a smartphone. An apnoea-hypopnoea index (AHI) ⩾ 5 events h−1 from simultaneous in-lab polysomnography was used to confirm moderate-to-severe childhood OSAHS. Symbolic dynamics was used to parameterise non-linear changes in the overnight oximetry profile. Conventional indices, anthropometric measures, and time-domain linear statistics were also considered. Forward stepwise logistic regression was used to obtain an optimum feature subset. Logistic regression (LR) was used to identify children with moderate-to-severe OSAHS. Main results: The histogram of 3-symbol words from symbolic dynamics showed significant differences (p < 0.01) between children with AHI < 5 events h−1 and moderate-to-severe patients (AHI ⩾ 5 events h−1). Words representing increasing oximetry values after apnoeic events (re-saturations) showed relevant diagnostic information. Regarding the performance of individual characterization approaches, the LR model composed of features from symbolic dynamics alone reached a maximum performance of 78.4% accuracy (65.2% sensitivity; 86.8% specificity) and 0.83 area under the ROC curve (AUC). The classification performance improved combining all features. The optimum model from feature selection achieved 83.3% accuracy (73.5% sensitivity; 89.5% specificity) and 0.89 AUC, significantly (p <0.01) outperforming the other models. Significance: Symbolic dynamics provides complementary information to conventional oximetry analysis enabling reliable detection of moderate-to-severe paediatric OSAHS from portable oximetry