Síntesis y caracterización de óxidos mixtos Ce₀.₈ZrₓLa₀.₂-ₓO₂ y su evaluación en la eliminación catalítica simultánea del negro de carbón y óxidos de nitrógeno

El interés en el saneamiento de los gases de escape provenientes de motores Diésel se ha incrementado significativamente; debido a que en los últimos años los índices de contaminación por partículas suspendidas (principalmente negro de carbón u hollín) y óxidos de nitrógeno se han disparado de manera preocupante. La presencia de estos agentes contaminantes en la atmosfera provoca enfermedades relacionadas con el sistema respiratorio del ser humano y causa daños considerables al medio ambiente. Para la eliminación simultánea de los óxidos de nitrógeno y del hollín se han estudiado catalizadores con características oxidantes: óxidos simples y óxidos mixtos. En particular, los óxidos mixtos a base de CeO₂ dopado con metales de transición cuyos óxidos presentan buenas características oxidantes han mostrado buenos resultados. En este trabajo se estudiaron los óxidos mixtos Ce₀.₈ZrₓLa₀.₂-ₓO₂preparados mediante el método de combustión utilizando glicina como combustible. Los materiales se caracterizaron por las técnicas de reducción a temperatura programada y difracción de rayos-X y posteriormente se evaluaron catalíticamente en condiciones representativas del escape del motor Diésel.The interest in cleaning diesel exhaust gases has increased significantly; because pollution levels, due to a large presence of nitrogen oxides and soot, have increased in recent years. The presence of these pollutants in the environment causes diseases related to the respiratory system of humans and damages to natural environment. For simultaneous removing of nitrogen oxides and soot some single and mixed oxides catalysts have been studied. Particularly CeO₂-based mixed oxides doped with oxidizing transition metals have showed good performance. The goal of this work was to study catalytic performances in simultaneous removal of soot and NOx of Ce₀.₈ZrₓLa₀.₂-ₓO₂catalysts prepared through combustion method using glycine as fuel. The materials were characterized by XRD and TPR techniques

Photoperiod-Treatment in Mediterranean Bucks Can Improve the Reproductive Performance of the Male Effect Depending on the Extent of Their Seasonality

This study examines the effectiveness of the photoperiod treatment (extra light for 88 days) to render the bucks sexually active during the seasonal anoestrous in order to induce a male effect, depending on the reproductive seasonality of the breed of the bucks used. In April, 57 anoestrous Blanca Andaluza does were distributed into four groups with three males each: 13 were exposed to control Murciano–Granadina bucks (lower seasonality); 15 were exposed to photostimulated Murciano–Granadina bucks; 14 were exposed to control Blanca Andaluza bucks (higher seasonality), and 15 were exposed to photostimulated Blanca Andaluza bucks. After male introduction, the sexual behaviour of the bucks was assessed, and harness marks recorded doe oestrous behaviour. Ovulation was confirmed from plasma progesterone, and the ovulation rate was assessed by transrectal ultrasonography. Fecundity, fertility, prolificacy and productivity were also determined. All of the does in all of the groups showed ovulation. Interaction between both sources of variation was observed: the percentage of females showing oestrous (p < 0.01) and productivity (p < 0.05) was the lowest in the Blanca Andaluza control group (50% and 0.36 ± 0.17 goat kids born/female, respectively). In conclusion, photoperiod-treated bucks efficiently induce a male effect, but photostimulation could be more necessary for breeds with deep seasonality

Efficacy of long day photoperiod treatment with respect to age of bucks for stimulation of the “male effect” on does at Mediterranean latitudes

This study examines whether the photostimulation of sexual activity in young bucks improves the reproductive performance of the "male effect" in comparison to adult males. The experimental design was a 2x2 with to variables: age of bucks and photoperiodic treatment of bucks. Ninety-three anoestrous does were distributed into four groups depending on the kind of male used: young bucks (1.26 years old, n = 6) or old bucks (5.15 years old, n = 6). Half of each group of males were subjected to a photoperiodic treatment or a natural photoperiod. After the males were introduced, the sexual behaviour of the bucks was assessed for 10 days, and doe oestrous behaviour was recorded. Ovulation was confirmed from plasma progesterone concentration, and ovulation rate was assessed by transrectal ultrasonography. Fecundity, fertility, prolificacy and productivity were also determined. The females in contact with young bucks showed a higher percentage of ovulation (100% vs 81%, P<0.01) and oestrous (82% vs 64%, P<0.05) than females in contact with old bucks. The females in contact with photostimulated bucks showed higher percentages of oestrous (88% vs 60%, P<0.01), fertility (78% vs 44%, P<0.01) and productivity (1.08 ± 0.10 vs 0.60 ± 0.12 P<0.01) than females in contact with control bucks. No interaction between both factors (age and photoperiod treatment) on any studied variable was observed. In conclusion, the response to the "male effect" was higher when using young bucks or photostimulated bucks, and produced 48 additional kids for every 100 females in the mating group compared to does exposed to untreated bucks.This research was supported by Grant AGL2016-75848-R from MINECO-AEI-FEDER (Spain). Thanks are also owed to CEI CamBio for their support. The authors wish to thank the farm staff of Huelva University for their technical support. Funding for open access charge: Universidad de Huelva / CBUA

Photoperiod-treated bucks are equal to melatonin-treated bucks for inducing reproductive behaviour and physiological functions via the "male effect" in Mediterranean goats

International audienceThe aim of this study was to examine whether photoperiod-treated bucks have the same capacity as melatonin-treated bucks to induce reproductive responses in female goats during the spring. On 10 April, 38 anoestrous does were placed with: 1) photoperiod-treated bucks (additional light hours for 83 days from the end of the previous November; PHOTO; n = 12); 2) bucks treated with exogenous melatonin at the beginning of March (MEL; n = 13); and 3) bucks that received no treatments (CONTROL; n = 13). The bucks' sexual behaviour was assessed for 10 days, and doe oestrous behaviour was recorded for the next 32 days by checking for harness marks. Ovulation was confirmed from plasma progesterone concentration (measured twice per week) and ovulation rate was assessed by transrectal ultrasonography. Fecundity, fertility, prolificacy and productivity were also determined. The percentage of does in the PHOTO, MEL and CONTROL group: 1) having ovulations was 92%, 100% and 38% respectively; 2) expressing behavioural oestrous associated with ovulation was 92%, 100% and 31%; and 3) that became pregnant was 75%, 69% and 23%, respectively. The kids produced per doe were 1.08 +/- 0.23, 1.15 +/- 0.25 and 0.31 +/- 0.17 for the PHOTO, MEL, and CONTROL groups, respectively with there being no differences between the PHOTO and MEL groups, however, there was a difference (P < 0.05) between PHOTO/MEL and CONTROL groups. Thus, imposing a stimulatory lighting regimen during the preceding winter period is as efficient as using subcutaneous melatonin implants in stimulating reproductive behaviours and physiological functions of bucks

The isolation of females from males to promote a later male effect is unnecessary if the bucks used are sexually active

It has been suggested that female goats in permanent contact with males become refractory to their presence, and need to be previously separated from them for 40–45 days if the presence of bucks is to induce reproductive activity, ovulation and oestrous during seasonal anoestrous. The present study examines the reproductive response (ovulation and oestrus) and reproductive performance of does isolated from bucks for different periods before their reintroduction to male company. A total of 103 Payoya and Blanca Andaluza does were distributed into six treatment groups that required their isolation from males for different periods: 0 days (N = 29), 5 days (N = 15), 10 days (N = 14), 20 days (N = 16), 30 days (N = 14) and 39 days (N = 15). After this period they were introduced to sexually active bucks (ensured to be in this condition by keeping them under long days light treatment for three months), and oestrous activity was recorded daily by direct visual observation of the marks left by the marking harnesses worn by these males. Ovulation was confirmed via the plasma progesterone concentration (measured in blood samples taken twice per week). The ovulation rate was assessed by transrectal ultrasonography. Fecundity, fertility, prolificacy and productivity were also determined. The sexual behaviour of the males towards the females was also monitored on Days 0, 1, 2, 3, 4, 8 and 9 after their meeting with the latter. The length of the female isolation period had no effect on the percentage of does that responded to contact with the males, nor did it affect the oestrous response, fecundity, fertility or productivity. The males, however, undertook more ano-genital sniffing and nudging with the 5 day group females compared to those of the other groups (P < 0.05). However, the sexual behaviour of the males changed as the days passed, with ano-genital sniffing becoming less common, and nudging, licking, sneezing and mounts with intromission more frequent on Days 8 and 9 than on Day 0, 1 and 2 after the sexes were reunited (P < 0.05). These results show that the isolation of females is not necessary for an efficient male effect if the bucks used are sexually active. In addition, the sexual behaviour of the bucks changes as the time in contact with the does increases, but in general is not affected by the duration of female isolation.The authors thank the Asociaci on Nacional de Criadores de Ganado Caprino de Raza Blanca Andaluza (ABLANSE) for supplying the animals used. This study was funded by Grant AGL2012-31733 and Grant AGL2016-75848-R from MICINN (Spain). The authors thank Adrian Burton for the English revision of the manuscript. Thanks are also owed to CEI CamBio for their support

Óxidos mixtos Ce₀.₈ZrxMn₀.₂-XO₂ como catalizadores en la eliminación simultánea de negro de carbón y óxidos de nitrógeno

Los óxidos de nitrógeno (NOx) y el hollín (negro de carbón), que son los principales gases contaminantes provenientes de los motores Diésel, han incrementado los índices de contaminación ambiental en los últimos años. La presencia de estos agentes contaminantes en la atmósfera provoca enfermedades relacionadas con el sistema respiratorio, afectando principalmente a niños y adultos mayores. La eliminación de estos contaminantes se puede realizar vía catalítica mediante óxidos u óxidos mixtos con fuerte carácter oxidante. En este trabajo, se sintetizó una serie de óxidos mixtos Ce₀.₈ZrxMn₀.₂-XO₂ (x = 0, 0.15, 0.10, 0.05 y 0.2) mediante el método de combustión utilizando glicina como combustible. Los sólidos se caracterizaron por difracción de rayos-X y reducción a temperatura programada. En la evaluación catalítica el sólido con composición Ce₀.₈Zr₀.₁₅Mn₀.₀₅O₂ mostró el mejor desempeño presentando un máximo de formación de CO₂ a 397 °C con 100 % de selectividad hacia el CO₂ y 6 % de remoción de NOx.Nitrogen oxides (NOx) and soot are the main pollutant gases from diesel engines. In recent years they are responsible for increasing the levels of environmental pollution. Their presence in the atmosphere causes respiratory diseases, affecting mainly children and elderly people. For simultaneous removal of NOx and soot many catalysts have been studied, mainly oxides and mixed oxides. In this work, a series of mixed oxides Ce₀.₈ZrxMn₀.₂-XO₂ (x = 0, 0.15, 0.10, 0.05 y 0.2) was synthesized by the combustion method using glycine as fuel. The solids were characterized by XRD and TPR, finally catalytic tests were conducted. The catalyst Ce₀.₈Zr₀.₁₅Mn₀.₀₅O₂ exhibited the best performance in simultaneous removal of NOx and soot showing high selectivity to CO₂ at 397 °C, and 6 % of NOx removal

Removal of phosphate and aluminum from water in single and binary systems using iron-modified carbons

The simultaneous removal of phosphate and aluminum from water was studied on iron-modified activated carbons. Methods such as oxidation with HNO3, impregnation and co-precipitation of iron were used to modify a commercial coconut activated carbon and to obtain seven different modified carbons. The physicochemical properties of selected samples were studied by different analytic methods such as FT-IR spectroscopy, SEM/EDX analysis and X-ray diffraction. Adsorption studies of phosphate and aluminum from water in single and binary systems were performed in bath systems with constant agitation at 30 °C and different values of pH. Particularly, the sample obtained by Oxidation-Impregnation-Drying procedure (CCOFeTB) contains 3.80% of iron in amorphous phase according to the EDX and XRD analysis, respectively. Additionally, this sample showed the best adsorption performance achieving an adsorbed amount of phosphates of 23.33 mg/g at pH 2 in single system. In binary systems, it was observed a synergistic effect in the adsorption of both species (phosphate and aluminum) and the principal adsorption mechanism is related to electrostatic interactions according with the results of molecular simulation.This work was supported by TECNM (7949.20-P), Ministerio de Economía, Industria y Competitividad, Spain (CTQ2017-87820-R) and PCTI-Asturias/FEDER, Spain, EU (IDI/2018/000118) projects. MC. Delgadillo-Velasco acknowledges the grant (467325) received from CONACyT. L.A. Ramírez-Montoya thanks CONACyT for a post-doctoral grant (CVU No 330625, 2017).Peer reviewe

La geografía y la economía en sus vínculos actuales : una antología comentada del debate contemporáneo

Desde hace décadas, La Geografía y la Economía han forjado un espacio de discusión que debate sobre las intersecciones dadas entre ambas disciplinas. A raíz del surgimiento de la llamada Nueva Geografía Económica, asociada al laureado Premio Nobel de Economía, Paul Krugman, ha surgido un intenso debate acerca de los vínculos entre estas dos ramas del conocimiento y de su relevancia para las Ciencias Sociales de hoy en día. A su vez, dicho debate se ha visto enriquecido con el avance metodológico que tanto la Geografía como la Economía han experimentado en años recientes, para estudiar analítica y empíricamente diversos procesos regionales

Mis casos Clínicos de Odontopediatría y Ortodoncia

Libro que conjunta casos en el área de Odontopediatría y OrtodonciaEs para los integrantes de la Red de Investigación en Estomatología (RIE) una enorme alegría presentar el tercer libro del 2021, sobre casos clínicos, revisiones de la literatura e investigaciones. La RIE está integrada por cuerpos académicos de la UAEH, UAEM, UAC y UdeG