How does flowering magnitude affect seed survival in Shorea pilosa (Dipterocarpaceae) at the predispersal stage in Malaysia?

General flowering (GF), a supra-annual, irregular fluctuation in flowering and seeding at the community level, is a phenomenon unique to the tropical rainforests of South-East Asia. To test the animal pollination and predator satiation hypotheses, which are the main hypotheses that attempt to explain the ultimate cause of GF, we conducted a bagging experiment after the flowering of Shorea pilosa (Dipterocarpaceae). Seed survival at the predispersal stage was divided into two stages (1–30 days and > 30 days after flowering) and we compared the results between treatments and between GF and non-GF periods using a survival analysis. Survival during the GF period at both stages was significantly higher than during non-GF periods, suggesting that both hypotheses were supported and that synchronous flowering with GF benefits the reproductive success of S. pilosa .     

Difference in cuticular transpiration and sclerophylly in juvenile and adult pine needles relates to the species-specific rates of development

Pinus species show remarkable ontogenetic differences in needle morphology (heterophylly) between juvenile and adult vegetative phases. This developmental shift may play an adaptative role in their success under diverse habitats. As a first step to know the functional differences between each vegetative phase, we compared water loss through the cuticles of juvenile and adult needles of 21-month-old nursery-grown seedlings of nine hard pine species. Cuticular transpiration (CT), calculated after complete stomatal closure, was obtained by leaf-drying curves, and was related to leaf, ontogenetic and climatic parameters. The rate of cuticular transpiration (RCT) between juvenile and adult needles differed across pine species, and in particular segregated the Mediterranean species Pinus canariensis and P. halepensis, from the Eurasian P. uncinata and introduced species P. radiata. For these species, RCT was always higher in juvenile needles. The different leaf and ontogenic parameters studied were correlated with the variation in RCT among the nine pine species. We discuss this relationship in the light of the species ecology. Besides their possible adaptive interpretation, these results suggest an underlying need to consider the ontogenetic heterophylly when assessing functional traits in hard pine seedlings, in particular those traits that govern water relations.     

Biogas generation apple pulp

In view of the pressing problem that appears in our region (Asturias, north of Spain) with the residues from the cider production, it was decided to test this kind of material as a co-substrate joint with slaughterhouse waste in a laboratory unit.     

The evolution of superstitious and superstition-like behaviour

Superstitious behaviours, which arise through the incorrect assignment of cause and effect, receive considerable attention in psychology and popular culture. Perhaps owing to their seeming irrationality, however, they receive little attention in evolutionary biology. Here we develop a simple model to define the condition under which natural selection will favour assigning causality between two events. This leads to an intuitive inequality--akin to an amalgam of Hamilton's rule and Pascal's wager--that shows that natural selection can favour strategies that lead to frequent errors in assessment as long as the occasional correct response carries a large fitness benefit. It follows that incorrect responses are the most common when the probability that two events are really associated is low to moderate: very strong associations are rarely incorrect, while natural selection will rarely favour making very weak associations. Extending the model to include multiple events identifies conditions under which natural selection can favour associating events that are never causally related. Specifically, limitations on assigning causal probabilities to pairs of events can favour strategies that lump non-causal associations with causal ones. We conclude that behaviours which are, or appear, superstitious are an inevitable feature of adaptive behaviour in all organisms, including ourselves.     

Network-based diffusion analysis: a new method for detecting social learning

Social learning has been documented in a wide diversity of animals. In free-living animals, however, it has been difficult to discern whether animals learn socially by observing other group members or asocially by acquiring a new behaviour independently. We addressed this challenge by developing network-based diffusion analysis (NBDA), which analyses the spread of traits through animal groups and takes into account that social network structure directs social learning opportunities. NBDA fits agent-based models of social and asocial learning to the observed data using maximum-likelihood estimation. The underlying learning mechanism can then be identified using model selection based on the Akaike information criterion. We tested our method with artificially created learning data that are based on a real-world co-feeding network of macaques. NBDA is better able to discriminate between social and asocial learning in comparison with diffusion curve analysis, the main method that was previously applied in this context. NBDA thus offers a new, more reliable statistical test of learning mechanisms. In addition, it can be used to address a wide range of questions related to social learning, such as identifying behavioural strategies used by animals when deciding whom to copy.     

造血干细胞生物学——研究与展望

造血干细胞（hematopoietic stem cell,HSC）是目前研究方法最为多样、研究技术手段最为成熟的一类组织干细胞,并且已经被成功运用于临床上对白血病以及先天性免疫缺陷等疾病的治疗。近年来,通过对一系列“转基因”与“基因敲除”小鼠模型的分析,人们对造血干细胞在胚胎早期发育过程中的发生与起源、造血干细胞“自我更新”与“定向分化”的调节机制、骨髓中造血干细胞的微环境（niche）对造血干细胞功能维持的调控,以及造血干细胞与白血病干细胞之间的相互关系等诸多方面都取得了很大的进展。如何实现造血干细胞的体外长期培养与扩增,实现胚胎干细胞（embryonic stem cell,ESC）或诱导多能干细胞（induced pluripotent stem cell,iPS细胞）向造血干细胞进行有效的定向分化,以及探索造血干细胞在病理状态（如癌症、贫血、衰老等）或应激状态下（如炎症与感染、组织损伤、代谢异常等）的功能变化,都将会是今后造血干细胞研究的重要方向。     

大鼠体外循环模型的建立及改进

目的对现有大鼠体外循环模型予以改进,降低模型复制难度,并使之更适合用于研究体外循环对肺功能的影响。方法成年雄性SD大鼠16只,体重300～350g,各8只分别用于建模和供血。经右颈静脉、左股静脉引流,右股动脉人工灌注建立体外循环,血气分析监测内环境变化。实验过程中,保留大鼠自主呼吸,不进行机械通气。结果成功建成8只大鼠体外循环模型并按计划顺利脱离人工循环。体外循环期间转流量为70～80mL/（kg·min）,血流动力学监测和血气分析结果基本正常。结论进一步简化了建立大鼠体外循环模型的操作,最显著的改进之处在于避免了机械通气对大鼠肺功能潜在的不良效应,从而更加适合用于研究体外循环对肺功能的影响。     

几种动物肝脏糖胺聚糖的醋酸纤维素薄膜电泳分析

采用酶解和离子交换色谱的方法,从兔、鸡、猪和羊肝组织中提取和纯化得到了糖胺聚糖（GAGs）.通过比较透明质酸（HA）、硫酸软骨素A（CS-A）、硫酸软骨素C（CS-C）、硫酸皮肤素（DS）、肝素（HP）、硫酸乙酰肝素（HS）等标准品在醋酸钡、醋酸锌、吡啶-甲酸等几种不同缓冲体系下的醋酸纤维素薄膜电泳行为,结合灰度积分建立了适合于微量GAGs定性和定量分析的电泳方法.将从不同动物肝脏组织中提取的GAGs运用该方法进行分析,发现 不同动物肝脏组织中,GAG含量和组成均有较大差异：羊肝中GAGs含量最高（0.52 mg/g 组织干粉）,种类也最丰富,含有HA、HS、DS和CS,其中HA所占比例最高;鸡肝中GAGs含量最少（0.18 mg/g组织干粉）,主要含有HA和DS;兔肝GAGs种类与猪肝相似,均含有HA、HS和DS,但HS是猪肝GAGs的主要成分,DS是兔肝GAGs的主要成分.     

Heritability of resting metabolic rate in a wild population of blue tits

We report the first study with the aim to estimate heritability in a wild population, a nest box breeding population of blue tits. We estimated heritability as well as genetic and phenotypic correlations of resting metabolic rate (RMR), body mass and tarsus length with an animal model based on data from a split cross‐fostering experiment with brood size manipulations. RMR and body mass, but not tarsus length, showed significant levels of explained variation but for different underlying reasons. In body mass, the contribution to the explained variation is mainly because of a strong brood effect, while in RMR it is mainly because of a high heritability. The additive variance in RMR was significant and the heritability was estimated to 0.59. The estimates of heritability of body mass (0.08) and tarsus length (0.00) were both low and based on nonsignificant additive variances. Thus, given the low heritability (and additive variances) in body mass and tarsus length the potential for direct selection on RMR independent of the two traits is high in this population. However, the strong phenotypic correlation between RMR and mass (0.643 ± 0.079) was partly accounted for by a potentially strong, although highly uncertain, genetic correlation (1.178 ± 0.456) between the two traits. This indicates that the additive variance of body mass, although low, might still somewhat constrain the independent evolvability of RMR.     

Identification of sow-specific risk factors for late pregnancy loss during the seasonal infertility period in pigs

Reduced farrowing rates due to late pregnancy loss (LPL) is a manifestation of seasonal infertility in pigs. This study was undertaken to determine sow- and gilt-specific risk factors leading to LPL during the seasonal infertility period (January to April) in Australia. Age at first service was considered to be a major gilt-specific risk factor, whereas sow-specific factors considered included parity, prior wean-to-service interval, prior lactation length, and number of piglets weaned in the lactation period immediately preceding the mating/pregnancy event under scrutiny. Logistic regression analysis of these factors was undertaken on 13,213 animals from three farms (Farms A, B, and C). Age at first service for gilts had an effect on LPL (P < 0.05) on Farm C when compared with that for Farms A and B, with those mated at approximately 220 d having the lowest rate of LPL. For older sows, parity was a factor on Farms A and C (P < 0.001), with the proportion of sows with LPL increasing with increasing parity. When the data from each farm were combined and analyzed, there was a significant farm by WSI interaction, with animals from Farm C being most at-risk for LPL. Sows with shorter lactation periods (P < 0.05) and smaller litters (P < 0.05) at the previous lactation had a greater chance of LPL on all farms. Under the conditions of this study, we were able to identify risk factors for LPL that producers can manipulate during the seasonal infertility period to improve breeding herd productivity.