CHANGES IN THE PERCEIVED TEXTURAL PROPERTIES OF CHEDDAR CHEESE DURING MATURATION

The perceived textural attributes of an English Cheddar were measured by a trained panel at various intervals during ripening, including those corresponding to mild and medium maturation times for this variety. The moisture content and pH were also monitored. After the recommended ripening period of 50 weeks the matured cheese was significantly less springy, firmer, harder, crumblier and creamier, indicating that textural attributes are related to the age of the Cheddar. Measures beyond the recommended maturation period revealed further significant differences. Comparisons of the measures taken at mild, medium and full maturity also revealed differences in the textural properties of the different classes of Cheddar. Significant correlations (p ≥0.01) between pH and springiness, crumbliness by fingers and creaminess suggested a strong relationship between these textural attributes and the extent of proteolysis. The results of this study revealed a strong relationship between age and the textural attributes of cheddar when restricted to one particular variety.     

Inhibiteurs non acides et dormance embryonnaire chez Taxus baccata

Non-acidic inhibitors and embryo dormancy in Taxus baccata L. Embryo dormancy of Taxus baccata is eliminated when the embryos are continuously kept in sterile nutritive liquid medium. After 3 weeks of culture, an important non-acidic inhibitory complex can be extracted from this liquid medium. At least three substances are involved: two pigments and a compound with some properties that suggest xanthoxin. These substances are neither found in embryos taken directly from the seeds, nor in liquid medium after 8 days of culture, which is the time necessary and sufficient to allow germination after transfer on agar medium. Such behaviour is quite different from that of ABA previously studied and indicates that these non-acidic inhibitors appear late during the culture and are not directly involved in embryo dormancy.     

Area and Age of Secondary Forests in Brazilian Amazonia 1978–2002: An Empirical Estimate

In quantifying the carbon budget of the Amazon region, temporal estimates of the extent and age of regenerating tropical forests are fundamental. However, retrieving such information from remote-sensing data is difficult, largely because of spectral similarities between different successional stages and variations in the reflectance of forests following different pathways of regeneration. In this study, secondary-forest dynamics in Brazilian Amazonia were modeled for the 1978–2002 period to determine area and age on a grid basis. We modeled the area, age, and age class distribution of secondary forests using empirical relationships with the percentage of remaining primary forest, as determined from large-area remote-sensing campaigns (the Pathfinder and Prodes projects). The statistical models were calibrated using detailed maps of secondary-forest age generated for seven sites in the Brazilian Legal Amazon. The area–age distribution was then specified from mean age by a distribution assumption. Over the period 1978–2002, secondary-forest area was shown to have increased from 29,000 to 161,000 km² (that is, by a factor of 5). The mean age increased from 4.4 to 4.8 years. We generated a time series of secondary-forest area fractions and successional stages that provides wall-to-wall coverage of the Brazilian Amazon at a spatial resolution of 0.1 decimal degrees (approximately 11 km). Validation against reference data yielded root mean squared errors of 8% of the total area for estimate of secondary-forest area and 2.4 years for mean secondary-forest age. Using this approach, we provide the first published update on the state of secondary forests in Amazonia since the early 1990s and a time series of secondary-forest area over the 25-year period.     

Decidualisation in the Prepuberal Rat Uterus

Decidualisation has been experimentally induced in the prepuberal rat. It is morphologically similar to that obtained in the adult. The cytodifferentiation includes the formation of binucleated cells and extensive specialised cellular junctions.
Furthermore, blastocysts from adults transferred into uterine horns of immature specimens implant and develop, indicating that the decidual response they induce is functionally comparable to the uterine response at the time of nidation in the fertilised adult.
The model of the experimental decidual induction in the immature is used to study the ontogenic processes of uterine maturation. Preliminary observations indicate that the 7–10-days period might be of significance in the maturation of the rat uterus.     

链球菌脂蛋白的功能作用及其作为疫苗候选蛋白和抗菌药物靶标的研究进展

脂蛋白是一类广泛存在于革兰氏阴性细菌和革兰氏阳性细菌中的细胞膜锚定蛋白,具有多种生物学功能.脂蛋白不仅作为细菌的毒力因子,而且能够识别和激活宿主的免疫系统,是当前预防和治疗细菌感染的热门靶点之一,本文对链球菌中脂蛋白的主要功能及其在疫苗和抗菌药物研究中的进展进行了综述和展望,为今后链球菌中脂蛋白的深入研究拓宽了思路.     

Response thresholds alone cannot explain empirical patterns of division of labor in social insects

The effects of heterogeneity in group composition remain a major hurdle to our understanding of collective behavior across disciplines. In social insects, division of labor (DOL) is an emergent, colony-level trait thought to depend on colony composition. Theoretically, behavioral response threshold models have most commonly been employed to investigate the impact of heterogeneity on DOL. However, empirical studies that systematically test their predictions are lacking because they require control over colony composition and the ability to monitor individual behavior in groups, both of which are challenging. Here, we employ automated behavioral tracking in 120 colonies of the clonal raider ant with unparalleled control over genetic, morphological, and demographic composition. We find that each of these sources of variation in colony composition generates a distinct pattern of behavioral organization, ranging from the amplification to the dampening of inherent behavioral differences in heterogeneous colonies. Furthermore, larvae modulate interactions between adults, exacerbating the apparent complexity. Models based on threshold variation alone only partially recapitulate these empirical patterns. However, by incorporating the potential for variability in task efficiency among adults and task demand among larvae, we account for all the observed phenomena. Our findings highlight the significance of previously overlooked parameters pertaining to both larvae and workers, allow the formulation of theoretical predictions for increasing colony complexity, and suggest new avenues of empirical study.

This study uses automated tracking of clonal raider ants and mathematical modeling to reveal how previously overlooked traits of larvae and workers might shape social organization in heterogeneous ant colonies. By incorporating the potential for variability in task efficiency among adults and task demand among larvae, the authors were able to account for all empirically observed phenomena.