Penny ice cap cores, baffin island, canada, and the wisconsinan foxe dome connection: two states of hudson bay ice cover

Ice cores from Penny Ice Cap, Baffin Island, Canada, provide continuous Holocene records of oxygen isotopic composition (delta18O, proxy for temperature) and atmospheric impurities. A time scale was established with the use of altered seasonal variations, some volcanic horizons, and the age for the end of the Wisconsin ice age determined from the GRIP and GISP2 ice cores. There is pre-Holocene ice near the bed. The change in delta18O since the last glacial maximum (LGM) is at least 12.5 per mil, compared with an expected value of 7 per mil, suggesting that LGM ice originated at the much higher elevations of the then existing Foxe Dome and Foxe Ridge of the Laurentide Ice Sheet. The LGM delta18O values suggest thick ice frozen to the bed of Hudson Bay.     

Solid substrate for production of Alternaria alternata conidia: a potential mycoherbicide for the control of Eichhornia crassipes (water hyacinth)

Eichhornia crassipes (water hyacinth), a major aquatic weed in India, is one of the targets in a biological weed control research programme in India. A fungal pathogen, Alternaria alternata, is being evaluated as a biological control agent for this weed. The feasibility of solid substrate for the mass production of A. alternata has been examined. Conidia production and virulence of A. alternata were affected by temperature, light and incubation period. The highest number of conidia were produced on rice seed followed by wheat, sorghum, maize seeds and cornmeal at 20°C when exposed to near‐ultraviolet than on the other substrates, while the least conidia were observed on these substrates under light conditions. At 20°C, large numbers of virulent conidia were produced on rice seeds after 4 weeks of incubation under constant dark conditions. Henceforth, the use of rice seeds as a solid substrate for production of A. alternata could be a feasible method to produce conidia in a village co‐operative scenario in India.     

Patterns of oocyte development in natural habitat and captive <Emphasis Type="Italic">Salminus hilarii</Emphasis> Valenciennes, 1850 (Teleostei: Characidae)

Fecundity and oocyte development in Salminus hilarii female brood stock were analyzed with the aim of investigating the impact of migration impediment on oogenesis. Histological analyses of the ovaries were performed in adult females caught in two different environments—the Tietê River (natural) and captivity—and the gonadossomatic index, oocyte diameter and fecundity determined. Five germ cell development stages (oogonium, perinucleolar, cortical alveoli, vitellogenic, ripe) and two other structures (postovulatory follicles and atretic oocytes) were observed in females caught in the river. Captive animals lacked the ripe oocytes and postovulatory follicles and had a relatively higher number of atretic oocytes. Females in captivity are known to produce larger oocytes, and they release fewer eggs in each spawn (absolute fecundity) when compared with animals that are able to migrate. Our results suggest that the Tietê River is undergoing alterations which are being reflected in the reproductive performance of S. hilarii, mainly due to the presence of atretic oocytes in females caught in the river. The lack of postovulatory follicles and ripe oocytes in captive animals reveals that migratory impediment negatively impacts final oocyte maturation. However, the stage of maturation reached is adequate for ovulation induction with hormone manipulation.     

Invasive tilapia juveniles are associated with degraded river habitats

• 1. Invasions are a main concern for conservationists. Identification of causes that raise or promote an invader's success is one of the first steps for preventing and/or fighting against invasions.
• 2. In the Brazilian River Paraiba do Sul, juveniles of invasive tilapia Oreochromis niloticus were detected associated with degraded habitats (mainly pollution from various sources). The relative abundance of juveniles of the competitor native species pearl cichlid Geophagus brasiliensis, morphologically and ecologically very similar, was negatively associated with habitat degradation.
• 3. A species‐specific molecular marker was employed to permit unambiguous identification of these small juveniles (2–3 cm long), which represent the most vulnerable life stage of both species.
• 4. It is suggested that adaptation to degraded habitats is one of the characteristics of invasive species, and consequently habitat conservation and restoration may help to prevent fish invasions.

Copyright © 2008 John Wiley & Sons, Ltd.     

Effect of Proofing Time and Wheat Flour Strength on Bleaching,Sensory Characteristics,and Volume of French Breads with Added Soybean Lipoxygenase

Soybean lipoxygenase addition in wheat bread doughs is widely used to improve the crumb color and rheology but little is known about the variability of the activity of lipoxygenase under diverse breadmaking conditions. Thus the objective of this study was to evaluate how soybean lipoxygenase can affect bleaching, volume, and sensory characteristics of French breads when proofing time and wheat flour strength varies. A 3-factor Box-Behnken design was used in this study containing one block and three independent variables or factors designated by exogenous lipoxygenase activity (x₁ = 0–71 unit/μg of protein), wheat flour deformation energy (x₂ = 231–258 × 10^–4 J), and proofing time (x₃ = 2–6 hr). Breads were randomly prepared and all assays were repeated three times. Specific volume (from 5.8 ± 0.4 to 9.9 ± 0.4 cm³/g), sensory quality (from 5.2 ± 0.8 to 8.3 ± 0.6), and yellow hue (from 12.6 ± 0.5 to 16.2 ± 0.3) significantly changed (P < 0.01) among the treatments. Specific volume of the breads increased with higher values of wheat flour strength and proofing time (ŷ_vs = 7.5 + 0.9 x₂ + 1.2 x₃ +0.5 x₂x₃). Sensory quality improved at higher values of wheat flour strength and shorter proofing time (ŷ_sq = 7.8 + 0.7 x₂ – 0.2 x₃ – 0.4 x₂² – 0.6x₃² + 0.5 x₂x₃), while lower and more desirable values of yellow hue were achieved at longer proofing time, higher activity of lipoxygenase, and using stronger wheat flours (ŷ_b = 13.7 – 1.2 x₁ – 0.5 x₂ – 0.2 x₃ + 1.0 x₁² – 0.3 x₁x₂). All regression models showed a good fitness to the experimental data (lack-of-fit P > 0.05) and the difference between predicted and observed values were also not significant (P < 0.05). Our results suggested that proofing time and wheat flour strength have a greater effect on volume and sensory quality of French breads than soybean lipoxygenase. However, the bleaching effect of this enzyme showed positive interaction with proofing time and wheat flour strength, suggesting its application even when strong wheat flours are used for the manufacture of French breads.     

Methane emission of Santa Inês sheep fed cottonseed by-products containing different levels of gossypol

The aim of this study was to evaluate the methane (CH₄) emission of Santa Inês sheep fed cottonseed by-products, verifying if the gossypol content of these feedstuffs affects CH₄ emission. Twelve late-lactating Santa Inês sheep (44.8?±?7.5 kg body weight (BW)) were allocated in metabolic cages for an experimental period of 19 days, 14 days for adaptation and 5 days for measuring CH₄ emission and dry matter intake (DMI). The animals were divided into four treatments, established in accordance with the cottonseed by-product used in concentrate formulation: Control (CON - no cottonseed by-product), Whole cottonseed (WCS), Cottonseed cake (CSC), and Cottonseed meal (CSM). The free gossypol level of the concentrates were 0, 1,276, 350, and 190 ppm for CON, WCS, CSC, and CSM, respectively. Also, the animals received Cynodon dactylon cv. Coast Cross hay, water, and mineral salt ad libitum. The ether extract content of the diets was balanced between treatments by including soybean oil in concentrates. The technique used to measure the CH₄ emission was the sulfur hexafluoride (SF₆) tracer technique, and the gas samples collected were quantified by analysis in gas chromatography system. The CH₄ emission was evaluated considering the daily emission (g CH₄/day); DMI (g CH₄/kg DMI); and BW (g CH₄/kg BW). No statistical difference was found (P?>?0.05) between treatments for DMI and CH₄ parameters. In the regression analysis, no significant relation (P?>?0.05) between gossypol content and CH₄ emission was observed. These results suggest that gossypol does not affect rumen methanogenesis.