Características físicas dos ovos da perdiz vermelha (Alectoris rufa) criada em cativeiro

The objective of the present study was to evaluate the effects of female age (1, 2 and 3-year-old) and month of laying (March, April and May) on the physical characteristics of the red-legged partridge eggs reared in captivity. O objetivo do presente estudo foi avaliar os efeitos da idade das fêmeas (um, dois e três anos) e do mês de postura (março, abril e maio) sobre as características físicas dos ovos da perdiz vermelha (Alectoris rufa) criada em cativeiro. O peso (W), o comprimento máximo (L) e a largura máxima (B) de 2878 ovos foram determinados diretamente, enquanto o índice de forma (B/L), o volume (V) e a superfície (S) foram calculados com base nos parâmetros determinados diretamente. A análise mostrou diferenças significativas (P0,05). Observaram-se diferenças significativas (P<0,01) na largura máxima e no índice de forma do ovo entre as diferentes classes de idades, com valores mais elevados nas fêmeas mais velhas e no período de postura mais tardio. O volume dos ovos estimados por meio de V1 = 0,51LB2 e V2=0,913W foi afetado significativamente (P<0,01) pela idade e pelo mês de postura, bem como as áreas, S1=4.835W0,662, S2=4,951V10,666 e S3=4,951V20,666, as quais apresentaram os mesmos efeitos. Palavras-chave: perdiz vermelha, Alectoris rufa, características dos ovo

Assessing foraging strategies of herbivores in Mediterranean oak woodlands: a review of key issues and selected methodologies.

Montados are agro-silvo-pastoral ecosystems, typical of the Southwest Iberian Peninsula, of high socio-economic and conservation importance,where grazing is a dominant activity. Montados are characterized by na open tree canopy of Quercus sp. and a diverse undercover of shrubs and grasslands that constitute the plant food resources for grazing animals. Plant food resources of Montados are highly variable, both spatially and seasonally, in quantity and quality. Reliable and easy to use methods to monitor grazing are necessary to allow proper understanding of foraging strategies of grazing animals and to set sustainable grazing management. We describe the main characteristics of the plant food resources available for grazing animals, striking its variability, and revise the potential of using N-alkanes and saliva

Anaerobic degradation of dairy wastewater in intermittent UASB reactors: influence of effluent recirculation

This work studied the influence of effluent recirculation upon the kinetics of anaerobic degradation of dairy wastewater in the feedless phase of intermittent upflow anaerobic sludge bed (UASB) reactors. Several laboratory-scale tests were performed with different organic loads in closed circuit UASB reactors inoculated with adapted flocculent sludge. The data obtained were used for determination of specific substrate removal rates and specific methane production rates, and adjusted to kinetic models. A high initial substrate removal was observed in all tests due to adsorption of organic matter onto the anaerobic biomass which was not accompanied by biological substrate degradation as measured by methane production. Initial methane production rate was about 45% of initial soluble and colloidal substrate removal rate. This discrepancy between methane production rate and substrate removal rate was observed mainly on the first day of all experiments and was attenuated on the second day, suggesting that the feedless period of intermittent UASB reactors treating dairy wastewater should be longer than one day. Effluent recirculation expressively raised the rate of removal of soluble and colloidal substrate and methane productivity, as compared with results for similar assays in batch reactors without recirculation. The observed bed expansion was due to the biogas production and the application of effluent recirculation led to a sludge bed contraction after all the substrates were degraded. The settleability of the anaerobic sludge improved by the introduction of effluent recirculation this effect being more pronounced for the higher loads

Sulfate reduction during the acidification of sucrose at pH 5 under thermophilic (55 degrees C) conditions. I: Effect of trace metals

This work studied the effect of supplying trace metals (7.5 mu M Fe and 0.5 mu M Co, Ni, Mn, Zn, Cu, B, Se, Mo and W) on sulfate reduction and acidification in thermophilic (55 degrees C) UASB reactors fed with sucrose (4 gCOD (I-reactor d)(-1)) operated at a reactor mixed liquor pH controlled at 5. Trace metals were supplied to one UASB reactor and were omitted from the influent of a second UASB reactor. The influence of different trace metal concentrations was further assessed in batch tests performed with the sludge from the UASB reactor receiving no trace metals. The absence of trace metals in the influent did not affect the performance of the acidifying UASB reactor throughout the 305 day long reactor run, but supplying low concentrations of trace metals inhibited sulfate reduction

Sulfate reduction during the acidification of sucrose at pH 5 under thermophilic (55 degrees C) conditions. II: Effect of sulfide and COD/SO42- ratio

This work studied the effect of the sulfide concentration and COD/SO42- ratios (4 and 1) on sulfate reduction and acidification in a thermophilic (55 degrees C) UASB reactor fed with sucrose (4 g COD (I-reactor d)(-1)) operated at a reactor mixed liquor pH controlled at 5 for a period of 301 days. When implementing N-2 stripping, sulfate reduction efficiencies up to 95%, corresponding to volumetric sulfate reduction rates of 0.87 and 4.2 g (I-reactor d)(-1) at the COD/SO42- ratios of 4 and 1, respectively, were achieved. Sulfide was toxic to sulfate reduction at a total dissolved sulfide concentration of 100 mg l(-1). Acidification was always complete and acetate was the only form of substrate in the effluent at a COD/SO42- ratio of 1. The sludge was well retained in the reactor and kept its granular shape throughout the reactor run

Effect of COD/SO42- ratio and sulfide on thermophilic (55°C) sulfate reduction during the acidification of sucrose at pH 6

This study investigated the effect of the COD/SO42¿ ratio (4 and 1) and the sulfide concentration on the performance of thermophilic (55 °C) acidifying (pH 6) upflow anaerobic sludge bed reactors fed with sucrose at an organic loading rate of 4.5 g COD lreactor¿1 day¿1. Sulfate reduction efficiencies amounted to 65% and 25¿35% for the COD/SO42¿ ratios of 4 and 1, respectively. Acidification was complete at all the tested conditions and the electron flow was similar at the two COD/SO42¿ ratios applied. The stepwise decrease of the sulfide concentrations in the reactors with a COD/SO42¿ ratio of 1 by N2 stripping caused an immediate stepwise increase in the sulfate reduction efficiencies, indicating a reversible inhibition by sulfide. The degree of reversibility was, however, affected by the growth conditions of the sludge. Acidifying sludge pre-grown at pH 6, at a COD/SO42¿ ratio of 9 and exposed for 150 days to 115 mg l¿1 sulfide, showed a slower recovery from the sulfide inhibition than a freshly harvested sludge from a full scale treatment plant (pH 7 and COD/SO42¿=9.5) exposed for a 70 days to 200 mg l¿1 sulfide. In the latter case, the decrease of the sulfide concentration from 200 to 45 mg l¿1 (35 mg l¿1 undissociated sulfide) by N2 stripping caused an immediate increase of the sulfate reduction efficiency from 35% to 96%

Low pH (6, 5, and 4) sulfate reduction during the acidification of sucrose under thermophilic (55°C) conditions

The effect of a low pH (6, 5 and 4) and different COD/SO42¿ ratios (9 and 3.5) on thermophilic (55 °C) sulfate reduction and acidification of sucrose was investigated using three upflow anaerobic sludge bed reactors fed with sucrose at an organic loading rate of 3.5 gCOD (lreactor d)¿1. The three reactors showed nearly 100% acidification of sucrose for all pH values and COD/SO42¿ ratios investigated. Sulfate reduction was complete at pH 6 and a COD/SO42¿ ratio of 9. At pH 5, sulfate reduction efficiencies were 80¿95% for both COD/SO42¿ ratios (9 and 3.5). At pH 4, sulfate reduction efficiencies further dropped to 55¿65% at a COD/SO42¿ ratio of 9 and 30¿40% at a COD/SO42¿ ratio of 3.5. The pH decrease from 6 to 5 or 4 caused a shift in the acidification products from mainly acetate to butyrate, as well as a higher production of ethanol, especially at pH 4. At pH 4, propionate and methane were not formed and hydrogen concentrations in the biogas reached 50%, equivalent to a hydrogen yield of 1.3 mol H2 (mol glucose)¿1. This study shows that sulfate reduction is possible in the acidification phase of anaerobic wastewater treatment at pH values as low as 6 till 4 and that the pH strongly affects both the acidification pathways and the sulfate reduction efficiencies

Comparison of CSTR and UASB reactor configuration for the treatment of sulfate rich wastewaters under acidifying conditions

The effects of lowering the operational pH from 6 to 5 on mesophilic (30 degrees C) sulfate reduction during the acidification of sucrose at an organic loading rate of 5 gCOD(1(reactor)d)(-1) and at a COD/SO42- ratio of 4 were evaluated in a CSTR and in a UASB reactor. The HRT was 24 h and 10 h, respectively. Acidification was complete in both reactors at pH 6 and the lowering of the operational pH to 5 did not affect the acidification efficiency in the CSTR but decreased the acidification efficiency of the UASB to 72%. The decrease to pH 5 caused an increase in the effluent butyrate and ethanol concentrations in both reactors. Lowering the pH from 6 to 5 caused a decrease in sulfate reduction efficiencies in both reactors, from 43% to 25% in the CSTR and from 95% to 34% in the UASB reactor. The acidification and sulfate reduction efficiencies at pH 5 could be increased to 94% and 67%, respectively, by increasing the HRT of the UASB reactor to 24 h.

Sulfate Reduction at pH 4 During the Thermophilic (55 degrees C) Acidification of Sucrose in UASB Reactors

Continuous sulfate reduction at pH 4.0 was demonstrated in a pH controlled thermophilic (55 degrees C) upflow anaerobic sludge bed reactor fed with sucrose at a COD/SO42- ratio of 0.9 and an organic loading rate of 0.8 and 1.9 gCOD (l(reactor) d)(-1) for a period of 78 days. A near v complete sulfate reduction efficiency was achieved throughout the reactor run, corresponding to sulfate removal rates of 0.91 and 1.92 g (l(reactor) d)(-1) at sulfate loading rates of 0.94 and 2 g (l(reactor) d)(-1), respectively, by keeping the sulfide concentration below 20 mg l(-1) due to stripping with nitrogen gas. Acidification was always complete and acetate was the only, degradation intermediate left in the effluent, which did not exceed 180 mgCOD l(-1) in pseudo-stationary states. The sludge was well retained ill the reactor and kept its granular form. A, Cu, Se, and Mo accumulated in the sludge, whereas Co, Ni, Fe, and Mn leached from the sludge, despite their continuous supply to the reactor via the influent. The bacterial diversity in the reactor sludge at the end of the reactor run was low and the culture was dominated by one acidifying species, resembling Thermoanaerobacterium sp., and one sulfate reducing species, resembling Desulfotomaculum sp

Physical characteristics of the eggs of red-legged partridge (Alectoris rufa) reared in captivity

O objetivo do presente estudo foi avaliar os efeitos da idade das fêmeas (um, dois e três anos) e do mês de postura (março, abril e maio) sobre as características físicas dos ovos da perdiz vermelha (Alectoris rufa) criada em cativeiro. O peso (W), o comprimento máximo (L) e a largura máxima (B) de 2878 ovos foram determinados diretamente, enquanto o índice de forma (B/L), o volume (V) e a superfície (S) foram calculados com base nos parâmetros determinados diretamente. A análise mostrou diferenças significativas (P0,05). Observaram-se diferenças significativas (P<0,01) na largura máxima e no índice de forma do ovo entre as diferentes classes de idades, com valores mais elevados nas fêmeas mais velhas e no período de postura mais tardio. O volume dos ovos estimados por meio de V1= 0,51LB2e V2=0,913W foi afetado significativamente (P<0,01) pela idade e pelo mês de postura, bem como as áreas, S1=4.835W0,662, S2=4,951V10,666e S3=4,951V20,666, as quais apresentaram os mesmos efeitos