Author Correction: Ancient DNA of Guinea Pigs (Cavia spp.) Indicates a Probable New Center of Domestication and Pathways of Global Distribution.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Ancient DNA of Guinea Pigs (Cavia spp.) Indicates a Probable New Center of Domestication and Pathways of Global Distribution.

Guinea pigs (Cavia spp.) have a long association with humans. From as early as 10,000 years ago they were a wild food source. Later, domesticated Cavia porcellus were dispersed well beyond their native range through pre-Columbian exchange networks and, more recently, widely across the globe. Here we present 46 complete mitogenomes of archaeological guinea pigs from sites in Peru, Bolivia, Colombia, the Caribbean, Belgium and the United States to elucidate their evolutionary history, origins and paths of dispersal. Our results indicate an independent centre of domestication of Cavia in the eastern Colombian Highlands. We identify a Peruvian origin for the initial introduction of domesticated guinea pigs (Cavia porcellus) beyond South America into the Caribbean. We also demonstrate that Peru was the probable source of the earliest known guinea pigs transported, as part of the exotic pet trade, to both Europe and the southeastern United States. Finally, we identify a modern reintroduction of guinea pigs to Puerto Rico, where local inhabitants use them for food. This research demonstrates that the natural and cultural history of guinea pigs is more complex than previously known and has implications for other studies regarding regional to global-scale studies of mammal domestication, translocation, and distribution.

Genome Sequences of Three Colombian Helicobacter pylori Strains Isolated from Tolimense Patients.

We present the complete genome sequences of three Helicobacter pylori strains isolated from patients who resided in Tolima Department, Colombia, diagnosed with chronic gastritis. The genomes present an average length of 1.6 Mbp and 1,546 genes and correspond to different H. pylori subpopulations.

Pollinator Preferences for Floral Volatiles Emitted by Dimorphic Anthers of a Buzz-Pollinated Herb.

Floral scents attract pollinators to plant rewards; in nectarless flowers, pollen grains are the only reward. Thus, pollen not only fertilizes ovules, but also feeds pollinators. This dilemma is resolved by specialization of anthers (i.e., heteranthery): feeding anthers that feed pollinators and pollinating anthers for fertilization. We hypothesized that the chemical composition of floral volatiles differs between the two types of anther and influences pollination preference for feeding anthers. We used Solanum rostratum as a study model because its heterantherous flowers produce a floral scent that suggests a close association with their pollinators. The main aim of this study was to determine the chemical composition of the two types of anther and to investigate how they influence foraging behaviour of pollinators. To characterize this composition, we used solid phase microextraction and hexane extraction followed by gas chromatography-mass spectrometry. We registered 12 volatile compounds in S. rostratum floral extracts, mainly aromatic and sesquiterpene compounds. The proportion of these compounds differed between feeding and pollinating anthers. Some of these compounds were probably emitted by osmophores located in both anther types. Also, we used electroantennography to investigate Melipona solani antennal response to floral volatiles. The M. solani antennae are receptive to the highest floral extract dose tested. Finally, we conducted two behavioural bioassays to test bee attraction for each type of floral extract: a) multiple-choice in a feeding arena using M. solani and b) Y-olfactometer bioassay using Bombus impatiens. Both bee species preferred feeding anthers in bioassays. In conclusion, heteranthery involves chemical differentiation (i.e., proportion of volatiles compounds) in anther specialization that influences bee preference for feeding anthers over pollinating anthers.

Nitrogen removal in domestic wastewater. Effect of nitrate recycling and COD/N ratio.

A denitrification/nitrification pilot plant was designed, built and put into operation, treating the effluent of an anaerobic reactor. The operation of the plant examined the effect of the nitrate recycling and the COD/N ratio on the nitrogen and the remaining organic matter removal at 18 °C. The system consisted of a two-stage treatment process: anoxic and aerobic. The hydraulic retention time (HRT) of the system was 1 h for the anoxic bioreactor and 2 h for the aerobic one. The increase in the nitrate recycling ratio did not cause a significant improvement in the nitrogen removal due to the insufficient carbon source. The wastewater to be treated had a C/N ratio of 1.1 showing a lack of organic carbon. The addition of methanol was a key point in the denitrification process used as a model for the traditional wastewater by-pass in the WWTP. The maximum nitrogen and organic matter removal (87.1% and 96%, respectively) was achieved with a nitrate recycling ratio of 600% and a C/N of 8.25, adjusted by methanol addition.

Sequencing batch reactor process for the removal of nitrogen from anaerobically treated domestic wastewater.

This work presents the performance of a sequencing batch reactor (SBR) system used as a means of removing nitrogen from domestic wastewater containing a low chemical oxygen demand (COD) to nitrogen ratio due to pre-treatment with an anaerobic reactor. The aim of the work was to determine the feasibility of this system for the removal of nitrogen from the domestic wastewater. An SBR with a working volume of 5 L was investigated at different cycle times of 12, 8 and 6 h, at 18 °C. The efficiency of the SBR varied together with the duration of the cycle, where the optimum performance was seen in the 6 h cycle with the anoxic-aerobic-anoxic sequence. Due to the low quantity of organic matter present in the domestic wastewater after the anaerobic treatment, an additional supply of external carbon was necessary before the second anoxic stage. The removal efficiencies obtained were: 98% for total Kjeldahl nitrogen, 84% for total nitrogen and 77% for soluble COD. The reactor was thus shown to be viable, and it was concluded that this process may be successfully applied as a post-treatment for the removal of nitrogen from anaerobically treated domestic wastewater.

Hydrodynamics of high solids anaerobic reactor: Characterization of solid segregation and liquid mixing pattern in a pilot plant VALORGA facility under different reactor geometry.

One of the main problems of dry anaerobic digestion plants treating urban solid waste is the loss of useful volume by the sedimentation of solids (inerts) into the bottom of the digester, or by accumulation of floating materials in its upper part. This entails a periodic cost of emptying and cleaning the digesters, a decrease in biogas production and complications in maintenance. Usually the sedimentation is a consequence of the heterogeneity of waste that, in addition to organic matter, drags particles of high density that end up obstructing the digesters. To reduce this bottleneck, URBASER has designed a new configuration of VALORGA reactor. That is, the VALORGA central wall has been removed and an inclined bottom has been added. To test the sedimentability and the overall performance of both configurations (current and new design), hydrodynamic tests have been carried out in a pilot digester (digester of 95 m3 capacity). To simulate the liquid phase and the solid phase of the reactor, lithium tracers and tags of different densities with RFID (radio frequency identification reader) have been used respectively. The results of the study showed an improvement in the performance of the new reactor design at pilot level.

Recirculation of gas emissions to achieve advanced denitrification of the effluent from the anaerobic treatment of domestic wastewater.

A denitrifying pilot plant was designed, constructed and operated for more than five months. The plant treated domestic wastewater with high ammonium nitrogen concentration, which had previously undergone an anaerobic process at 18 °C. The process consisted of one biofilter with 2 h of hydraulic retention time for denitritation. Different synthetic nitrite concentrations were supplied to the anoxic reactor to simulate the effluent of a nitritation process. This work investigates the advanced denitritation of wastewater using the organic matter and other alternative electron donors present in an anaerobic treatment process effluent: methane and sulfide. The denitrifying bacteria were able to treat wastewater at an inlet nitrite concentration of 75 mg NO2--N/L with a removal efficiency of 92.9%. When the inlet nitrite concentration was higher, the recirculation of the gas from the top of the anoxic reactor was successful to enhance the nitrite removal, achieving a NO2- elimination efficiency of 98.3%.

Denitrification of the anaerobic membrane bioreactor (AnMBR) effluent with alternative electron donors in domestic wastewater treatment.

A fixed film bioreactor for the denitrification of the effluent from an anaerobic membrane bioreactor (AnMBR) treating domestic wastewater was designed, built and investigated. After anaerobic treatment, the wastewater usually has a low C/N ratio (∼1.3), and a remaining chemical oxygen demand of around 117mg O2/L, which is not enough to make conventional heterotrophic denitrification possible. That effluent also holds methane and sulfide dissolved and oversaturated after leaving the AnMBR. This paper demonstrates the feasibility of using these reduced compounds as electron donors in order to remove 80mg NOx--N/L at 18°C and 2h of hydraulic retention time. In addition, the influence of the NO2-/NO3- ratios in the feed was studied. Total nitrogen removal was achieved in all the cases studied, except for a feed with 100% NO3-. Methane was the main electron donor used to remove the nitrites and nitrates, with a participation rate of over 70%.

Economic analysis of microaerobic removal of H2S from biogas in full-scale sludge digesters.

The application of microaerobic conditions during sludge digestion has been proven to be an efficient method for H2S removal from biogas. In this study, three microaerobic treatments were considered as an alternative to the technique of biogas desulfurization applied (FeCl3 dosing to the digesters) in a WWTP comprising three full-scale anaerobic reactors treating sewage sludge, depending on the reactant: pure O2 from cryogenic tanks, concentrated O2 from PSA generators, and air. These alternatives were compared in terms of net present value (NPV) with a fourth scenario consisting in the utilization of iron-sponge-bed filter inoculated with thiobacteria. The analysis revealed that the most profitable alternative to FeCl3 addition was the injection of concentrated O2 (0.0019 €/m(3) biogas), and this scenario presented the highest robustness towards variations in the price of FeCl3, electricity, and in the H2S concentration.

Co-digestion of municipal sewage sludge and solid waste: modelling of carbohydrate, lipid and protein content influence.

Solid wastes from industrial, commercial and community activities are of growing concern as the total volume of waste produced continues to increase. The knowledge of the specific composition and characteristics of the waste is an important tool in the correct development of the anaerobic digestion process. The problems derived from the anaerobic digestion of sole substrates with high lipid, carbohydrate or protein content lead to the co-digestion of these substrates with another disposed waste, such as sewage sludge. The kinetic of the anaerobic digestion is especially difficult to explain adequately, although some mathematical models are able to represent the main aspects of a biological system, thus improving understanding of the parameters involved in the process. The aim of this work is to evaluate the experimental biochemical methane potential on the co-digestion of sewage sludge with different solid wastes (grease; spent grain and cow manure) through the implementation of four kinetic models. The co-digestion of grease waste and mixed sludge obtained the best improvements from the sole substrates, with additional positive synergistic effects. The Gompertz model fits the experimental biochemical methane potential to an accuracy of 99%, showing a correlation between the percentage of lipid in the substrates and co-digestions and the period of lag phase.

Theoretical methane production generated by the co-digestion of organic fraction municipal solid waste and biological sludge.

The co-digestion of two problematic and available wastes, namely Organic Fraction Municipal Solid Waste (OFMSW) and biological sludge, was carried out in this work. Biochemical Methane Potential (BMP) tests are a useful tool for determining the best substrate and co-digestion configurations, however there are some methodologies destined to save costs and time from this process by using the theoretical final methane potential of a substrate from its organic composition. Besides there are some models capable not only of reproducing the methane curve behavior, but also of predicting final methane productions from the first days of experimentation. Methodologies based in the elemental composition for the determination of theoretical production fit better with the experimental results and behavior, nevertheless the Gompertz model was capable of predicting the final productivity within the 7th day of experiment, selecting at the same time the co-digestion of 80% OFMSW and 20% Biological sludge as the optimum.

Afección laríngea obstructiva y síndrome de apnea obstructiva del sueño, una asociación con severo riesgo perioperatorio / Obstructive laryngeal disease and obstructive sleep apnoea syndrome, a combination with serious peri-operative risk

Presentamos el caso de una paciente con diagnósticos de bronquitis crónica, síndrome de apnea obstructiva del sueño y edemas laríngeos de gran tamaño que se intervino para resección mediante microcirugía transoral láser. En el postoperatorio inmediato desarrolló una insuficiencia respiratoria aguda por colapso faríngeo que requirió reintubación en condiciones de urgencia y traslado a UCI no prevista, en la que se mantuvo la ventilación mecánica durante 18 h, procediendo a continuación a la extubación. La evolución posterior fue normal. Se describe la asociación de varios factores de riesgo para el tratamiento anestésico y la importancia de detectar en el preoperatorio la gravedad de cada una de las alteraciones, especialmente la severidad del síndrome de apnea obstructiva del sueño (AU)

We present the case of a patient who was diagnosed with chronic bronchitis, obstructive sleep apnoea syndrome, and large Reinke laryngeal oedemas that were removed by transoral laser microsurgery. In the immediate post-operative period acute respiratory insufficiency occurred due to pharyngeal collapse that required emergency re-intubation, after which the patient was transferred to the ICU where mechanical ventilation was given for18 h. Subsequent progress was normal. We describe the combination of various risk-factors related to anaesthetic management and the importance of considering each one of them, especially the preoperative detection of the severity of obstructive sleep apnoea syndrome (AU)

Where does the removal of H2S from biogas occur in microaerobic reactors?

In order to maximise the efficiency of biogas desulphurisation and reduce the oxygen cost during microaerobic digestion, it is essential to know how the process occurs. For this purpose, a reactor with a total volume of 266 L, treating 10 L/d of sewage sludge, was operated with 25.0 L and without headspace. Under anaerobic conditions, the H2S concentration in the biogas varied between 0.21 and 0.38%v/v. Next, O2 was supplied from the bottom of the reactor. At 0.25-0.30 NLO2/Lfed, the biogas was entirely desulphurised, and its O2 content remained below 1.03%v/v, when the digester had 25.0 L of gas space. However, with almost no headspace, the H2S content in the biogas fluctuated from 0.08 to 0.21%v/v, while the average O2 concentration was 1.66%v/v. The removed H2S accumulated in the outlet pipe of the biogas in the form of S(0) due to the insufficient headspace.

El Score de Gaslini y el caso de fiebre mediterránea familiar que se disfrazó de PFAPA / The Gaslini Score and the case of Familial Mediterranean Fever who dressed up as PFAPA

Ante un niño con episodios recurrentes de fiebre acompañada de faringoamigdalitis aguda, pero con cultivos faríngeos negativos, debemos sospechar que se trate de un PFAPA (periodic fever, aftous stomatitis, pharyngitis y cervical adenitis). Los criterios diagnósticos son sencillos pero inespecíficos, por lo que no pueden descartar otras enfermedades autoinflamatorias (EA). Se presenta el caso de una niña que sufría episodios recurrentes de fiebre, faringoamigdalitis con cultivos faríngeos negativos, diarrea leve, dolor abdominal frecuente y, en ocasiones, también otalgia. Cumplía los criterios diagnósticos de PFAPA pero, alertados por el resultado de "alto riesgo" obtenido en el Score de Gaslini, se estableció que en realidad la clínica se debía a una fiebre mediterránea familiar. Actualmente es ineficiente hacer un estudio genético en todos los casos con sospecha de EA hereditaria febril. Este artículo pretende recordar que tenemos a nuestra disposición el Score de Gaslini, una herramienta que, aunque imperfecta, es útil y sencilla para detectar casos con alta probabilidad de presentar otra EA que cursa con una clínica similar a la del PFAPA, pero que tiene un pronóstico y un tratamiento diferentes (AU)

In a child with recurrent episodes of fever accompanied by acute pharyngitis, but with negative throat cultures, we should suspect that it is a PFAPA (periodic fever, aftous stomatitis pharyngitis and cervical adenitis). The diagnostic criteria are simple but non-specific, so it is not possible to rule out other auto-inflammatory diseases. We present the case of a girl who suffered recurrent episodes of fever, pultaceous pharyngitis (with negative throat cultures), mild diarrhoea, frequent abdominal pain and sometimes otalgia as well. She fulfilled the diagnostic criteria for PFAPA, but, alerted by the result of "high risk" obtained with de Gaslini Score, it was discovered that, in fact, the symptoms were due to Familial Mediterranean Fever. Currently it is inefficient to carry out a genetic study in all cases with suspected hereditary febrile auto-inflammatory disease. This article tries to remind that we have at our disposal the Gaslini Score, a tool that, though imperfect, is useful and makes easy to detect cases with high probability of being another auto-inflammatory disease with clinical symptoms similar to those of the PFAPA, but with a worse prognosis and treatment

Grease waste and sewage sludge co-digestion enhancement by thermal hydrolysis: batch and fed-batch assays.

Grease waste (GW) is an adequate substrate for sewage sludge co-digestion since, coming from a waste water treatment plant, it has a high methane potential (489 NmLCH(4)/gVSin); however, no synergistic effect takes place when co-digesting with 52%VS grease. Conversely, thermal hydrolysis (TH) improves the anaerobic digestion of GW (43% higher kinetics) and biological sludge (29% more methane potential). Therefore, the application of TH to a co-digestion process was further studied. First, biochemical methane potential tests showed that the best configuration to implement the TH to the co-digestion process is pretreating the biological sludge alone, providing a 7.5% higher methane production (398 NmLCH(4)/gVSin), 20% faster kinetics and no lag-phase. Its implementation in a fed-batch operation resulted in considerable methane production (363 NmLCH(4)/gVSin) and TH improved the rheology and dewaterability properties of the digestate. This leads to important economical savings when combined with co-digestion, reducing final waste management costs and showing interesting potential for full-scale application.

Microaerobic digestion of sewage sludge on an industrial-pilot scale: the efficiency of biogas desulphurisation under different configurations and the impact of O2 on the microbial communities.

Biogas produced in an industrial-pilot scale sewage sludge reactor (5m(3)) was desulphurised by imposing microaerobic conditions. The H2S concentration removal efficiency was evaluated under various configurations: different mixing methods and O2 injection points. Biogas was entirely desulphurised under all the configurations set, while the O2 demand of the digester decreased over time. Although the H2S removal seemed to occur in the headspace, S(0) (which was found to be the main oxidation product) was scarcely deposited there in the headspace. O2 did not have a significant impact on the digestion performance; the VS removal remained around 47%. Conversely, DGGE revealed that the higher O2 transfer rate to the sludge maintained by biogas recirculation increased the microbial richness and evenness, and caused an important shift in the structure of the bacterial and the archaeal communities in the long term. All the archaeal genera identified (Methanosaeta, Methanospirillum and Methanoculleus) were present under both anaerobic and microaerobic conditions.

The headspace of microaerobic reactors: sulphide-oxidising population and the impact of cleaning on the efficiency of biogas desulphurisation.

O2-limiting/microaerobic conditions were applied in order to control the H2S content of biogas. The S(0)-rich deposits found all over the headspace of two pilot reactors (R1 and R2) as a result of operating under such conditions for 7 and 15 months (respectively) were sampled and removed. After restarting micro-oxygenation, H2S-free biogas was rapidly obtained, and the O2 demand of R2 decreased. This highlighted the need for a cleaning interval of less than 14 months in order to minimise the micro-oxygenation cost. The H2S removed from R2 after approximately 1 month was recovered from its headspace as S(0), thus indicating that the biogas desulphurisation did not take place at the liquid interface. Denaturing gradient gel electrophoresis indicated that the composition, species richness and size of the sulphide-oxidising bacteria population depended on the location, and, more specifically, moisture availability, and indicated increasing species richness over time. Additionally, a possible succession was estimated.

Thermal hydrolysis integration in the anaerobic digestion process of different solid wastes: energy and economic feasibility study.

An economic assessment of thermal hydrolysis as a pretreatment to anaerobic digestion has been achieved to evaluate its implementation in full-scale plants. Six different solid wastes have been studied, among them municipal solid waste (MSW). Thermal hydrolysis has been tested with batch lab-scale tests, from which an energy and economic assessment of three scenarios is performed: with and without energy integration (recovering heat to produce steam in a cogeneration plant), finally including the digestate management costs. Thermal hydrolysis has lead to an increase of the methane productions (up to 50%) and kinetics parameters (even double). The study has determined that a proper energy integration design could lead to important economic savings (5 €/t) and thermal hydrolysis can enhance up to 40% the incomes of the digestion plant, even doubling them when digestate management costs are considered. In a full-scale MSW treatment plant (30,000 t/year), thermal hydrolysis would provide almost 0.5 M€/year net benefits.

[Obstructive laryngeal disease and obstructive sleep apnoea syndrome, a combination with serious peri-operative risk]. / Afección laríngea obstructiva y síndrome de apnea obstructiva del sueño, una asociación con severo riesgo perioperatorio.

We present the case of a patient who was diagnosed with chronic bronchitis, obstructive sleep apnoea syndrome, and large Reinke laryngeal oedemas that were removed by transoral laser microsurgery. In the immediate post-operative period acute respiratory insufficiency occurred due to pharyngeal collapse that required emergency re-intubation, after which the patient was transferred to the ICU where mechanical ventilation was given for 18h. Subsequent progress was normal. We describe the combination of various risk-factors related to anaesthetic management and the importance of considering each one of them, especially the preoperative detection of the severity of obstructive sleep apnoea syndrome.