3,914 research outputs found
Seeking to enhance the bioenergy of municipal sludge: Effect of alkali pre-treatment and soluble organic matter supplementation
The aim of this research is to enhance the mesophilic anaerobic digestion of municipal sludge from
Cadiz-San Fernando (Spain) wastewater treatment plant at 20 days hydraulic retention time (HRT). Two
different strategies were tested to improve the process: co-digestion with the addition of soluble organic
matter (1% v/v); and alkali sludge pre-treatment (NaOH) prior to co-digestion with glycerine (1% v/v).
Methane production (MP) was substantially enhanced (from 0.36 ± 0.09 L CH4 l/d to 0.85 ± 0.16 L CH4
l/d), as was specific methane production (SMP) (from 0.20 ± 0.05 L CH4/g VS to 0.49 ± 0.09 L CH4/g VS)
when glycerine was added. The addition of glycerine does not seem to affect sludge stability, the
quality of the effluent in terms of pH and organic matter content, i.e. volatile fatty acids (VFA), soluble
organic matter and total volatile solid, or process stability (VFA/Alkalinity ratio < 0.4). Alkali
pre-treatment prior to co-digestion resulted in a high increase in soluble organic loading rates (more than
20%) and acidification yield (more than 50%). At 20 days HRT, however, it led to overload of the system and total destabilization of the mesophilic anaerobic co-digestion of sewage sludge and glycerine
Mesophilic anaerobic co-digestion of sewage sludge with glycerine: Effect of solids retention time
The main objective of this paper is to examine the effect of the increase in organic loading rates (OLRs), by
reducing the solids retention time (SRT) from 20 d to 5 d, in single-phase mesophilic anaerobic co-digestion of
sewage sludge with glycerine (1% v/v). It was experimentally confirmed that anaerobic co-digestion of these
biowastes under steady-state conditions can achieve an 85 ± 5% reduction in volatile fatty acids (VFA) at SRTs
of between 20 and 9 d, with a methane production yield of around 0.8 l CH4/l/d. Decreases in the SRT not only allow the sludge stability and biogas production to be maintained, but also lead to an increase in the waste that could be treated and lower operating costs. Therefore, mesophilic anaerobic co-digestion of sewage sludge and glycerin at a SRT lower than 20 d is possible and preferable due to being more economical and environmentally friendl
Production of unstable heavy neutrinos in photo-neutron stars
[EN] We discuss the production of a class of heavy sterile neutrinos nu(h) in proto-neutron stars. The neutrinos, of mass around 50 MeV, have a negligible mixing with the active species but relatively large dimension-5 electromagnetic couplings. In particular, a magnetic dipole moment mu approximate to 10(-6) GeV-1 implies that they are thermally produced through e(+)e(-) -> (nu) over bar (h)nu(h) in the early phase of the core collapse, whereas a heavy-light transition moment mu(tr) approximate to 10(-8) GeV-1 allows their decay nu(h) -> nu i gamma with a lifetime around 10(-3) s. This type of electromagnetic couplings has been recently proposed to explain the excess of electron-like events in baseline experiments. We show that the production and decay of these heavy neutrinos would transport energy from the central regions of the star to distances d approximate to 400 km, providing a very efficient mechanism to enhance the supernova shock front and heat the material behind it. (C) 2015 The Authors. Published by Elsevier B.V
Electro-optical Simulation of a-Si Thin-Film-Transistor Liquid Crystal Display Pixels
An analysis of an amorphous silicon (a-Si) thin-film-transistor liquid-crystal display (TFT-LCD) pixel is presented. The electro-optical model combines the electrical properties of the switching element and the optical performance of a twisted nematic (TN) liquid-crystal cell.Publicad
Controllable soliton emission from a Bose-Einstein condensate
We demonstrate, through numerical simulations, the controllable emission of
matter-wave bursts from a Bose-Einstein Condensate in a shallow optical dipole
trap. The process is triggered by spatial variations of the scattering length
along the trapping axis. In our approach, the outcoupling mechanism are
atom-atom interactions and thus, the trap remains unaltered. Once emitted, the
matter wave forms a robust soliton. We calculate analytically the parameters
for the experimental implementation of this atomic soliton machine gun.Comment: 4 pages, 5 figure
Diabetes insĂpida central en un perro
Se describe un caso de diabetes insĂpida central [DIC] en un perro. Este caso es particularmente interesante pues se observan modificaciones electrolĂticas poco habituales. En la discusiĂłn se comenta la posible etiologĂa del proceso, los hallazgos analĂticos y el procedimiento de diagnĂłstico elegido.It is described a case of canine central diabetes insipidus particularly interesting because is presented with very un usual electrolytic abnormalities. The etiology, the atypical electrolytic levels observed and the diagnostic method used are discussed
Characterization of a new partitivirus strain in Verticillium dahliae provides further evidence of the spread of the highly virulent defoliating pathotype through new introductions
The soilborne pathogen Verticillium dahliae, causal agent of Verticillium wilt, has a worldwide distribution and many hosts of agronomic value. The worldwide spread of a highly virulent defoliating (D) pathotype has greatly increased the threat posed by V. dahliae in olive trees. For effective disease management, it is important to know if the D pathotype is spreading long distances from contaminated material, or if D pathotype isolates may have originated locally from native V. dahliae populations several times. We identified a double-stranded RNA mycovirus in an olive D pathotype isolate from Turkey. Sequencing and phylogenetic analysis clustered the virus with members of the family Partitiviridae. The virus was most similar to a partitivirus previously identified in a V. dahliae isolate from cotton in China (VdPV1), with sequence identities of 94% and 91% at the nucleotide level for RNA1 and RNA2, respectively. The virus therefore corresponded to a strain of the established species, and we designated it VdPV1-ol (VdPV1 from olive). The identification of the same viral species in these two fungal isolates from geographically distant origins provides evidence of their relationships, supporting the hypothesis of long-distance movement of V. dahliae isolates.This research was supported by the Spanish Ministry
of Science and Innovation (Grants AGL2009-
13445), and the Junta de AndalucĂa (Grant FEDER
P07-TIC-02682) and AGL2013-48980-R.Peer reviewe
Helicobacter pylori Is Present at Quantifiable Levels in Raw Vegetables in the Mediterranean Area of Spain
[EN]
Vegetables are one of the main foodstuffs consumed in the Mediterranean diet. However, raw vegetables have been associated with relevant foodborne outbreaks worldwide. Accurate knowledge of the microbiological quantitative risks associated with these matrices is crucial in order to define effective control measures, avoiding the survival and dissemination of foodborne pathogens through the different food chain stages. The aim of the present study is the assessment of the prevalence of Helicobacter pylori (a unique carcinogenic biological agent recognized to date) on leafy vegetables (spinach, lettuce, and chard) by means of the detection of the specific pathogenicity vacA gene. A real-time quantitative polymerase chain reaction (qPCR) optimized approach was used to detect H. pylori-positive samples and the concentration of this pathogen (with a limit of detection equal to 10 cells). One hundred raw vegetable samples were acquired in markets corresponding to the Spanish Mediterranean area. Sliced vegetable leaves were homogenized and centrifuged, and DNA was extracted from the homogenates. qPCR results confirmed 20 out of 100 H. pylori-positive samples, with melting temperature (T-m) values in the range of 84.8-86.5 degrees C (T-m vacA H. pylori = 85 degrees C). Amplicons were cut, purified, and sequenced to confirm the homology with the H. pylori vacA gene. A total of 17 out of 100 vegetable samples (12/45 (26.6%) lettuce, 2/21 (9.5%) spinach, and 3/34 (8.8%) chard samples) were finally confirmed as H. pylori-positive. Contamination levels were in the range of 1.5 +/- 0.3 to 2.5 +/- 0.1 log(10) cycles (36-335 CFU/g leafy vegetables). Our results show that H. pylori is detected by qPCR at levels close to infectious doses in fresh vegetables, thus posing a food safety hazard.This research was funded by the Ministerio de Ciencia e Innovacion, Spain, grant number PID2019-105691RB-I00. M. Garcia-Ferrus is the recipient of a PEJ2018-003746A grant from Ministerio de Economia, Industria y Competitividad, Spain. Prof. Pina-Perez is also grateful to the GVA202/031 grant project.GarcĂa-FerrĂșs, M.; GonzĂĄlez Pellicer, A.; Pina-PĂ©rez, MC.; FerrĂșs PĂ©rez, MA. (2022). Helicobacter pylori Is Present at Quantifiable Levels in Raw Vegetables in the Mediterranean Area of Spain. Agriculture. 12(3):1-7. https://doi.org/10.3390/agriculture120303391712
RelaciĂłn entre el proceso histĂłrico: Tartessos / colonizaciĂłn fenicĂa y la Aita AndalucĂa.
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