Enhanced Sensitivity of CMOS Image Sensors by Stacked Diodes

We have investigated and compared the performance of photodiodes built with stacked p/n junctions operating in parallel versus conventional ones made with single p/n junctions. We propose a method to characterize and compare photodiodes sensitivity. For this purpose, a dedicated chip in the standard AMS 180-nm HV technology has been fabricated. Four different sensor structures were implemented and compared. Experimental results are provided. Measurements show sensitivity enhancement ranging from 55% to 70% within the 500-1100 nm spectral region. The larger increment is happening in the near infrared band (up to 62%). Such results make stacked photodiodes suitable candidates for the implementation of photosensors in vision chips designed for standard CMOS technologies.Ministerio de Economía y Competitividad TEC2012-33634, TEC2015-66878- C3-1-RJunta de Andalucía TIC 2012-2338Office of Naval Research (USA) N00014141035

Pueblo mapuche, estado y explotación forestal. Extractivismo y desigualdad en un conflicto socio-ambiental de larga data en Chile

La hipótesis que determina esta investigación sostiene que el extractivismo forestal se encuentra en la base de la relación del Estado Chileno con el pueblo mapuche, generando profundas modificaciones en su estructura social y organización política, ya que además de los impactos sociales y ambientales, ha implicado una disputa de las categorías que se le achacan a “lo mapuche” –bárbaros, subversivos, terroristas, etc.– , que a su vez han reorientado las demandas e incrementado la desigualdad. Como todo conflicto socio-ambiental, el conflicto forestal dialoga con conflictos de otra índole; étnicos, territoriales, sociales, etc. Se analizará por tanto como parte de esta complejidad a través de cinco principales etapas: 1. La ocupación militar del territorio mapuche a finales del siglo XIX y las primeras legislaciones forestales; 2. El proceso de Reforma Agraria durante los años 1964 y 1973, en donde se promueve la reforestación, y siguiente Contrarreforma Agraria en dictadura, marcada por la expulsión de los mapuches de las tierras que habían sido restituidas para su posterior remate. Momento en que las empresas privadas acceden a las tierras reforestadas y la actividad forestal se expande; 3. Los impactos ambientales y sociales; y 4. La radicalización del conflicto socio-ambiental y la violación de derechos del pueblo mapuch

Learning environments in compulsory secondary education (ESO): validation of the physical, learning, teaching and motivational scales

We present the validation of a questionnaire for compulsory secondary school students (seventh to tenth grade), designated “Educational learning environments for ESO pupils” (CEApA_ESO), for the purpose of evaluating learning environments. Although many instruments have been developed in this area, our work attempts to comprehensively cover some factors that most influence learning environments from the students’ perspective. Therefore, we included physical, learning, teaching and motivational elements, by adapting different already-validated scales to our intended overall approach and the Spanish context. We conducted a pilot study with 207 students from four grades (two classes per educational level). We performed descriptive and factor analyses with maximum likelihood extraction method and varimax rotation to identify factors underlying each scale. The factors extracted from each scale were used to evaluate the fit of the model, using the AMOS v.18 software for structural equation analysis, taking as reference the criteria set by Byrne (Structural equation modeling with AMOS: Basic concepts, applications, and programming, Taylor & Francis Group, 2010) and Kline (Principles and practice of structural equation modeling, The Guilford Press, 2010) (CMIN/DF between 2 and 5, CFI and IFI > 0.9, RMSEA 200). Finally, we present the factorial validity of the complete scale and analyse the internal consistency of the scale and its subscales using Cronbach’s alpha coefficient. This instrument, with adequate psychometric properties, offers educators and researchers a valid tool for assessing the learning environments of their schools.Funding for open access publishing: Universidad de Huelva /CBUA. The information we are collecting is part of the project entitled: “Analysis of learning environments in secondary schools in Andalusia. Quantitative study.” (Ref: UHU-1256187), within the call for ERDF projects financed by the European Union, Junta de Andalucía and Universidad de Huelva. This project is led by Dr. María del Pilar García Rodríguez and Dr. José Manuel Coronel Llamas

Effectiveness of mixtures of vivianite and organic materials in preventing iron chlorosis in strawberry

Application of Fe salts with different organic matter sources has been demonstrated to be effective in preventing Fe deficiency chlorosis. The main objective of this work was to study the effectiveness of different Fe sources based on mixtures of humic substances or compost with vivianite in preventing this nutritional disorder in strawberry (Fragaria × ananassa cv Camarosa). To this end, a randomised block experiment involving four replications (3 plants per replication) and one factor (Fe source) was performed in a greenhouse using a calcareous growing medium. Iron sources studied were: (i) control without Fe, (ii) control with an effective Fe source in calcareous media (EDDHA-Fe, 0.1 g kg–1), (iii) vivianite (1 g kg–1 medium, which is the recommended rate), (iv) vivianite (1 g kg–1) + humic substances (HS 0.06 g kg–1), (v) vivianite (0.5 g kg–1) + HS (0.06 g kg–1) and (vi) a mixture of composted cork residue and vivianite at a 6:1 mass ratio (CORVIV) applied at a dose of 6 g kg–1 medium. All Fe sources were effective in increasing SPAD readings when compared with control without Fe. Treatments based on vivianite provided non-significantly different SPAD readings from that obtained with EDDHA-Fe. However, only CORVIV showed non-significantly different dry matter (DM) production, leaf area index, and total Fe content in the aerial part than EDDHA-Fe. Humic substances and vivianite at 1 g kg–1 increased DM yield in plants when compared with vivianite without HS, results with this last treatment being similar to those obtained with vivianite at 0.5 g kg–1 with HS. It can be concluded that studied sources of organic matter increased the efficiency of vivianite in preventing Fe chlorosis in strawberry, especially vivianite enriched cork compost which was as effective as EDDHA-Fe

Improving the effect of incubation and oxidative stress on thawed spermatozoa from red deer by using different antioxidant treatments

P. 856-870Antioxidants could improve sperm media, extending the viability of spermatozoa and protecting their DNA. The protective ability of lipoic acid, melatonin, Trolox and crocin was tested on red deer spermatozoa incubated at 37°C. Cryopreserved spermatozoa were thawed and incubated with 1 mM or 0.1 mM of each antioxidant, with or without oxidative stress (100 μM Fe2+). Motility (CASA), viability, mitochondrial membrane potential and acrosomal status were assessed. Lipoperoxidation (malondialdehyde production), intracellular reactive oxygen species (ROS) and DNA status (TUNEL) were checked at 4 h. Incubation alone increased ROS and decreased motility. Oxidative stress intensified these effects, increasing lipoperoxidation and DNA damage. Lipoic acid had little protective effect, whereas 1 mM melatonin showed limited protection. Trolox lowered ROS and lipoperoxidation both in oxidised and non-oxidised samples. In oxidised samples, Trolox prevented DNA and acrosomal damage, and ameliorated motility. Crocin at 1 mM showed similar results to Trolox, but noticeably stimulated motility and had no effect on lipoperoxidation. In a second experiment, a broader range of crocin and melatonin concentrations were tested, confirming the effects of crocin (positive effects noticeable at 0.5–0.75 mM), but showing an increase in lipoperoxidation at 2 mM. Melatonin was increasingly effective at 2.5 and 5 mM (ROS, lipoperoxidation and DNA status). Crocin seems a promising new antioxidant, but its particular effects on sperm physiology must be further studied, especially the consequences of motility stimulation and confirming its effect on lipoperoxidation. Melatonin might be useful at relatively high concentrations, compared to Trolox.S

On the Optimal Identification of Tag Sets in Time-Constrained RFID Configurations

In Radio Frequency Identification facilities the identification delay of a set of tags is mainly caused by the random access nature of the reading protocol, yielding a random identification time of the set of tags. In this paper, the cumulative distribution function of the identification time is evaluated using a discrete time Markov chain for single-set time-constrained passive RFID systems, namely those ones where a single group of tags is assumed to be in the reading area and only for a bounded time (sojourn time) before leaving. In these scenarios some tags in a set may leave the reader coverage area unidentified. The probability of this event is obtained from the cumulative distribution function of the identification time as a function of the sojourn time. This result provides a suitable criterion to minimize the probability of losing tags. Besides, an identification strategy based on splitting the set of tags in smaller subsets is also considered. Results demonstrate that there are optimal splitting configurations that reduce the overall identification time while keeping the same probability of losing tags

Role of small-sized phytoplankton in triggering an ecosystem disruptive algal bloom in a Mediterranean hypersaline coastal lagoon

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