Sustainability of intensive groundwater development: experience in Spain

Intensive aquifer development is common in arid and semiarid countries. The associated economic and social benefits are great, but management is needed and sustainability has to be analysed in the framework of a sound hydrogeological background which includes recharge as a key term. Recharge under natural conditions may greatly differ from the actual value under groundwater exploitation conditions when the aquifer is connected to surface water bodies or evaporation conditions are modified. Actual recharge is not an aquifer property but is variable depending on groundwater abstraction and its pattern, and changes in surface water-groundwater relationships and other circumstances, such as return irrigation flows, leakages, and activities to artificially modify it. Groundwater plays an important role in nature as it sustains spring flow, river base flow, wetlands, and crypto-wetlands, and the related provision of ecological services to mankind. Therefore, developable groundwater resources and their sustainability have to take into account concurrence and the net benefits of capturing it in a given moment and not in other circumstances, and exchanging groundwater-related nature services for the human use of groundwater. The often large storage relative to annual flow of aquifers implies that aquifer development produces effects that may last decades and even affect upcoming human generations. This new dimension, which has economic and sustainability aspects, is not as important for other water resources. Critical flow thresholds have to be considered for groundwater-dependent ecosystems. This is considered from the point of view of water quantity, which is the dominant aspect under arid and semiarid conditions. However, water quality may be as or more important for humans and for nature services, but this needs a separate treatment. The hydrogeological and socio-economic aspects of aquifer behaviour are presented taking into account the experience drawn from some intensively exploited and economically and socially important aquifers, mostly those in La Mancha, in central Spain, but also other intensively exploited Spanish aquifers. Topdown-down administrative decisions to get a given sustainable have resulted in partial failures, but if action is agreed among stakeholders better outcomes could be achieved. Mixed solutions seem the best approach

On microarchitectural mechanisms for cache wearout reduction

Hot carrier injection (HCI) and bias temperature instability (BTI) are two of the main deleterious effects that increase a transistor's threshold voltage over the lifetime of a microprocessor. This voltage degradation causes slower transistor switching and eventually can result in faulty operation. HCI manifests itself when transistors switch from logic ''0'' to ''1'' and vice versa, whereas BTI is the result of a transistor maintaining the same logic value for an extended period of time. These failure mechanisms are especiall in those transistors used to implement the SRAM cells of first-level (L1) caches, which are frequently accessed, so they are critical to performance, and they are continuously aging. This paper focuses on microarchitectural solutions to reduce transistor aging effects induced by both HCI and BTI in the data array of L1 data caches. First, we show that the majority of cell flips are concentrated in a small number of specific bits within each data word. In addition, we also build upon the previous studies, showing that logic ''0'' is the most frequently written value in a cache by identifying which cells hold a given logic value for a significant amount of time. Based on these observations, this paper introduces a number of architectural techniques that spread the number of flips evenly across memory cells and reduce the amount of time that logic ''0'' values are stored in the cells by switchingThis work was supported in part by the Spanish Ministerio de Economía y Competitividad within the Plan E Funds under Grant TIN2015-66972-C5-1-R, in part by the HiPEAC Collaboration Grant funded by the FP7 HiPEAC Network of Excellence under Grant 287759, and in part by the Engineering and Physical Sciences Research Council under Grant EP/K 026399/1 and Grant EP/J016284/1

Enhancing the L1 Data Cache Design to Mitigate HCI

Over the lifetime of a microprocessor, the Hot Carrier Injection (HCI) phenomenon degrades the threshold voltage, which causes slower transistor switching and eventually results in timing violations and faulty operation. This effect appears when the memory cell contents flip from logic ‘0’ to ‘1’ and vice versa. In caches, the majority of cell flips are concentrated into only a few of the total memory cells that make up each data word. In addition, other researchers have noted that zero is the most commonly-stored data value in a cache, and have taken advantage of this behavior to propose data compression and power reduction techniques. Contrary to these works, we use this information to extend the lifetime of the caches by introducing two microarchitectural techniques that spread and reduce the number of flips across the first-level (L1) data cache cells. Experimental results show that, compared to the conventional approach, the proposed mechanisms reduce the highest cell flip peak up to 65.8%, whereas the threshold voltage degradation savings range from 32.0% to 79.9% depending on the application.This work has been supported by the Spanish Ministerio de Econom´ıa y Competitividad (MINECO), by FEDER funds through Grant TIN2012-38341-C04-01, by the Intel Early Career Faculty Honor Program Award, by a HiPEAC Collaboration Grant funded by the FP7 HiPEAC Network of Excellence under grant agreement 287759, and by the Engineering and Physical Sciences Research Council (EPSRC) through Grants EP/K026399/1 and EP/J016284/1.This is the author accepted manuscript. The final version is available from IEEE at http://dx.doi.org/10.1109/LCA.2015.2460736. The dataset associated with this article can be found on the repository at https://www.repository.cam.ac.uk/handle/1810/249006

Federating distributed clinical data for the prediction of adverse hypotensive events

The ability to predict adverse hypotensive events, where a patient's arterial blood pressure drops to abnormally low (and dangerous) levels, would be of major benefit to the fields of primary and secondary health care, and especially to the traumatic brain injury domain. A wealth of data exist in health care systems providing information on the major health indicators of patients in hospitals (blood pressure, temperature, heart rate, etc.). It is believed that if enough of these data could be drawn together and analysed in a systematic way, then a system could be built that will trigger an alarm predicting the onset of a hypotensive event over a useful time scale, e.g. half an hour in advance. In such circumstances, avoidance measures can be taken to prevent such events arising. This is the basis for the Avert-IT project (http://www.avert-it.org), a collaborative EU-funded project involving the construction of a hypotension alarm system exploiting Bayesian neural networks using techniques of data federation to bring together the relevant information for study and system development

Complete characterization of pruning waste from the lechero treen(Euphorbia laurifolia L.) as raw material for biofuel

[EN] The aim of this study is to conduct a complete characterization of the pruning waste from the lechero tree. This tree species is of particular relevance in Ecuador for its use as biomass since it yields large amounts of pruning waste, it has a high propagation capacity and very fast growth, for both the trunk and branches. The pruning waste consists of a mixture of wood and leaves, which are subjected to caloric analysis, elemental analysis, proximate analysis, thermogravimetric analysis and fermentability. The average dry pruned biomass obtained per tree is 9.95 kg, with a 1.49 kg standard deviation. The average ratio of leaves in pruned biomass is the 40%. Regression model to determine pruning waste biomass from plant measurements was obtained with 0.7 of r(2). The calorific value of these residues is 19 MJ/kg average. N and ash content is influenced by leaf content. A leaf content less than 25% represent N content lower than 1%, and 6% ash content. Prediction models to higher heat value (kJ/kg) based on elemental, proximate and structural analysis is presented.Velázquez Martí, B.; Gaibor-Chazvez, J.; Niño-Ruiz, Z.; Narbona-Sahuquillo, S. (2018). Complete characterization of pruning waste from the lechero treen(Euphorbia laurifolia L.) as raw material for biofuel. Renewable Energy. 129:629-637. https://doi.org/10.1016/j.renene.2018.06.050S62963712

Referrer Graph: A cost-effective algorithm and pruning method for predicting web accesses

This paper presents the Referrer Graph (RG) web prediction algorithm and a pruning method for the associated graph as a low-cost solution to predict next web users accesses. RG is aimed at being used in a real web system with prefetching capabilities without degrading its performance. The algorithm learns from users accesses and builds a Markov model. These kinds of algorithms use the sequence of the user accesses to make predictions. Unlike previous Markov model based proposals, the RG algorithm differentiates dependencies in objects of the same page from objects of different pages by using the object URI and the referrer in each request. Although its design permits us to build a simple data structure that is easier to handle and, consequently, needs lower computational cost in comparison with other algorithms, a pruning mechanism has been devised to avoid the continuous growing of this data structure. Results show that, compared with the best prediction algorithms proposed in the open literature, the RG algorithm achieves similar precision values and page latency savings but requiring much less computational and memory resources. Furthermore, when pruning is applied, additional and notable resource consumption savings can be achieved without degrading original performance. In order to reduce further the resource consumption, a mechanism to prune de graph has been devised, which reduces resource consumption of the baseline system without degrading the latency savings. 2013 Elsevier B.V. All rights reserved.This work has been partially supported by Spanish Ministry of Science and Innovation under Grant TIN2009-08201. The authors would also like to thank the technical staff of the School of Computer Science at the Polytechnic University of Valencia for providing us recent and customized trace files logged by their web server.De La Ossa Perez, BA.; Gil Salinas, JA.; Sahuquillo Borrás, J.; Pont Sanjuan, A. (2013). Referrer Graph: A cost-effective algorithm and pruning method for predicting web accesses. Computer Communications. 36(8):881-894. https://doi.org/10.1016/j.comcom.2013.02.005S88189436

Osteocalcin in serum, saliva and gingival crevicular fluid : their relation with periodontal treatment outcome in postmenopausal women

Antecedentes. Los niveles de osteocalcina se han propuesto como marcador de la inhibición de la formación ósea. El propósito de este trabajo es determinar las concentraciones de osteocalcina en plasma, saliva y fluido crevicular correlacionándolo con el resultado del tratamiento periodontal en mujeres postmenopáusicas. Pacientes y métodos. El estudio se realizó en treinta y nueve mujeres postmenopáusicas (57.8 ±8.5 años de edad). El examen periodontal incluyó el control de placa, el sangrado al sondaje, la profundidad de sondaje (PS) y la pérdida de inserción (CAL). Se determinaron los niveles de osteocalcina en suero, saliva y fluido crevicular. A continuación se llevó a cabo el tratamiento periodontal. Pasados seis meses tras la primera cita se llevó a cabo un segundo examen periodontal. Resultados. Las medias de la PS y del CAL disminuyeron significativamente en el segundo examen periodontal en el grupo de mujeres con osteocalcina en suero < 10 ng/ml (15.8± 15.8% y 15.3± 21.2%, respectivamente; p < 0.05). La PS media disminuyó significativamente en el segundo exámen en los grupos con concentraciones de osteocalcina en saliva < 3 ng/ml (17.1± 15.9%; p < 0.05) y 3 ? 7 ng/ml (16.2 ± 18.1%; p < 0.05). Conclusiones. Los niveles bajos de osteocalcina en suero se asocian significativamente a un mayor porcentaje de disminución de la PS y del CAL tras el tratamiento periodontal en mujeres postmenopáusicas. Las bajas concentraciones de osteocalcina en saliva se asociaron significativamente a un mayor porcentaje de disminución de la PS

PS-Dir: A Scalable Two-Level Directory Cache

As the number of cores increases in both incoming and future chip multiprocessors, coherence protocols must address novel hardware structures in order to scale in terms of performance, power, and area. It is well known that most blocks accessed by parallel applications are private (i.e., accessed by a single core). These blocks present different directory requirements and behavior than shared blocks. Based on this fact, this paper proposes a two-level directory cache that tracks shared blocks in a small and fast first-level cache and private blocks in a larger and slower second-level cache, namely Shared and Private caches, respectively. Speed and area reasons suggest the use of eDRAM technology much dense but slower than SRAM technology for the Private cache, which in turn brings energy savings. Experimental results for a 16-core system show improvements in performance by 11.1%, in area by 25.4%, and in energy consumption by 20.5% compared to a conventional directory cache.This work has been supported by the Spanish MICINN, as well as European Commission FEDER funds, under Grants CSD2006-00046 and TIN2009-14475-C04Valls, JJ.; Ros Bardisa, A.; Sahuquillo Borrás, J.; Gómez Requena, ME.; Duato Marín, JF. (2012). PS-Dir: A Scalable Two-Level Directory Cache. IEEE Computer Society. https://doi.org/10.1145/2370816.2370891