White-breasted Nuthatch ( Sitta carolinensis ) fecal sac dispersal in northwestern Nevada

Field research on the dispersal of fecal sacs by parent White-breasted Nuthatches ( Sitta carolinensis ) was conducted on the eastern slopes of the Sierra Nevada in northwestern Nevada. Fecal sacs were dropped 6-60 m from the nest, with 56% of the total droppings ( n = 66) being dropped 48-60 m away. Ninety-five percent of sac dispersal was in the southwest quadrant, the food-foraging site. Also, 75% of non-sac flights during the nestling phase were in the direction of the foraging area, a dead, mature Jeffrey pine ( Pinus jeffreyi ). Fecal sac dispersal by parent Whitebreasted Nuthatches may reduce or eliminate detection of nestlings by avian predators.     

Regulation of innate and adaptive immune responses by MAP kinase phosphatase 5

Mitogen-activated protein (MAP) kinases are essential regulators in immune responses, and their activities are modulated by kinases and phosphatases. MAP kinase phosphatase (MKP) is a family of dual-specificity phosphatases whose function is evolutionarily conserved. A number of mammalian MKPs have been identified so far, but their specific physiological functions in negative regulation of MAP kinases have not been genetically defined. Here we examine innate and adaptive immune responses in the absence of MKP5. JNK activity was selectively increased in Mkp5 (also known as Dusp10)-deficient mouse cells. Mkp5-deficient cells produced greatly enhanced levels of pro-inflammatory cytokines during innate immune responses and exhibited greater T-cell activation than their wild-type counterparts. However, Mkp5-deficient T cells proliferated poorly upon activation, which resulted in increased resistance to experimental autoimmune encephalomyelitis. By contrast, Mkp5-deficient CD4(+) and CD8(+) effector T cells produced significantly increased levels of cytokines compared with wild-type cells, which led to much more robust and rapidly fatal immune responses to secondary infection with lymphocytic choriomeningitis virus. Therefore, MKP5 has a principal function in both innate and adaptive immune responses, and represents a novel target for therapeutic intervention of immune diseases.     

Structure of the fibronectin type 1 module

The rapid accumulation of sequence data has provided insight into the evolution of proteins and led to the identification of 'mosaic proteins'. These proteins have evolved by duplication, insertion and deletion of a common pool of structural units or modules, yet their biological functions are diverse. They are involved in cell adhesion and migration, embryogenesis and the pathways of blood clotting, fibrinolysis and complement. The modular units are defined by 'consensus sequences' which often include conserved disulphide bonds. Despite the available sequence information, little is known of the tertiary structure of mosaic proteins. If, however, the 'consensus structure' of the modules were known, valuable structural information could be inferred about a wide variety of proteins and biological systems. An important mosaic protein is fibronectin, an extracellular matrix protein that consists of three types of module (see refs 3, 7 for reviews). Here we describe the structure of the fibronectin type 1 module which appears twelve times in fibronectin and is also found in factor XII and tissue plasminogen activator. The module was produced using a yeast expression system and the structure was determined in solution using 1H NMR. This methodology promises to be extremely powerful in the investigation of modules from a wide range of mosaic proteins.     

石羊河流域空气传播孢粉的初步研究

为了确定风长距离搬运的孢粉对干旱区尾闾型湖泊沉积物孢粉谱的贡献率，对干旱区典型的小流域--石羊河流域空气中的孢粉进行了分析．石羊河流域云杉树盛花期时，3个样点8个空气样孢粉分析显示，空气样孢粉组合与取样点植被状况大致相当，孢粉组合的空间变化基本上受现代植被分布状况控制，影响空气样孢粉谱和孢粉浓度的因素主要是取样时间和地点．在一定的范围内，干旱区风搬运孢粉的能力很强，可大量地搬运孢粉；但风长距离搬运孢粉的能力有限，超过一定距离，风搬运的孢粉数量还是很小的，风搬运的流域上游森林带的孢粉对中下游地区空气样孢粉谱的贡献率很小．     

Using the bootstrap for improved ARIMA model identification

This paper presents a new method of identifying ARIMA time-series models. We use the bootstrap technique in estimating the distribution of sample autocorrelations both separately and in a simultaneous inference setting. The bootstrap has the advantage of being nonparametric and thus free of reliance on asymptotic normality, which may not hold for short or medium-size series. The simultaneous procedure is unique, as it has no feasible parametric alternatives. An application to exchange rates illustrates our methodology. In the example chosen, we are able to produce better forecasts using the model identified via the bootstrap technique.