Marine bacteria associated with marine macroorganisms: the potential antimicrobial resources

In order to explore marine microorganisms with medical potential, marine bacteria were isolated from seawater, sediment, marine invertebrates and seaweeds collected from different coastal areas of the China Sea. The antimicrobial activities of these bacteria were investigated. Ethyl acetate extracts of marine bacterial fermentation were screened for antimicrobial activities using the method of agar diffusion. The results showed that 42 strains of the isolates have antimicrobial activity. The proportion of active bacteria associated with marine invertebrates (20%) and seaweeds (11%) is higher than that isolated from seawater (7%) and sediment (5%). The active marine bacteria were assigned to the genera Alteromonas, Pseudomonas, Bacillus and Flavobacterium. The TLC autobiographic overlay assay implied that the antimicrobial metabolites produced by four strains with wide antimicrobial spectrum were different. Due to a competitive role for space and nutrient, the marine bacteria associated with marine macroorganisms (invertebrates and seaweeds) could produce more antibiotic substances. These marine bacteria were expected to be potential resources of natural antibiotic products.

Seasonal changes in the distribution of dissolved organic nitrogen in coastal and open-ocean waters in the North East Pacific: sources and sinks

The distribution of dissolved organic nitrogen (DON) and nitrate were determined seasonally (winter, spring and summer) during three years along line P, i.e. an E-W transect from the coast of British Columbia, Canada, to Station P (50degreesN, 145degreesW) in the subarctic North East Pacific Ocean. In conjunction, DON measurements were made in the Straits of Juan de Fuca and Georgia within an estuarine system connected to the NE Pacific Ocean. The distribution of DON at the surface showed higher values of 4-17 muM in the Straits relative to values of 4-10 muM encountered along line P, respectively. Along line P, the concentration of DON showed an inshore-offshore gradient at the surface with higher values near the coast. The equation for the conservation of DON showed that horizontal transport of DON (inshore-offshore) was much larger than vertical physical mixing. Horizontal advection of DON-rich waters from the coastal estuarine system to the NE Pacific Ocean was likely the cause of the inshore-offshore gradient in the concentration of DON. Although the concentration of DON was very variable in space and time, it increased from winter to summer, with an average build up of 4.3 muM in the Straits and 0.7 muM in the NE subarctic Pacific. This implied seasonal DON sources of 0.3 mmol N m(-2) d(-1) at Station P and 1.5 mmol N m(-2) d(-1) in the Straits, respectively. These seasonal DON accumulation rates corresponded to about 15-20% of the seasonal nitrate uptake and suggested that there was a small seasonal build up of labile DON at the surface. However, the long residence times of 180-1560 d indicated that the most of the DON pool in surface waters was refractory in two very different productivity regimes of the NE Pacific. (C) 2002 Elsevier Science Ltd. All rights reserved.

Community structure of macrobenthos in coastal water off Rushan, southern Shandong Peninsula, and the relationships with environmental factors

To understand the present actuality of the marine ecosystem in the southern coastal water region of the Shandong Peninsula and the impact of the global change and the human activities to the marine ecosystem of the region, the macrobenthic community structure was researched based on data from 26 sampling stations carried out on four seasonal cruises from December 2006 to November 2007. The data was analyzed using PRIMER 6.0 and SPSS 15.0 software packages. The results showed that 236 macrobenthic species in total were collected from the research region by the field works. Most of the species belong to Polychaeta (76 species), Mollusca (75) and Crustacea (60). Of which, 33 species were common species by the four cruises. The dominant species were different among the four seasons, however, the polychaete species Nephtys oligobranchia and Sternaspis scutata were always dominant in the four seasons. The abundances and biomasses of the macrobenthos from the research region were variable in tire four seasons. The results of CLUSTER and MDS analysis showed that the similarities of macrobenthic structures among the stations were low, most of the similarities were at about 40% of similarity values, only that of two stations were up to 60%. In accordance with the similarity values of the macrobenthic structures, the 26 stations were clustered as six groups at arbitrary similarity level of 30%. The ABC curve indicated that the marcofauna communities in the research region had riot been disturbed distinctly. The results of BIOENV and BVSTEP (Spearman) analysis implied that the concentrations of organic matter in bottom water and heavy metal copper in sediment, water depth and temperature of bottom were the most significant environmental factors to affect the macrobentic community.

青藏高原矮嵩草草甸种子库的初步研究

The seed bank of Kobresia humilis meadow in Qing- Zang Plateau was preliminaryly studied and the relationships among seed bank , seed rain and above-ground vegetation were compared and analysed.The results showed that there were 23 species in the seed bank in both of green up and withering stage. In species composition of the seed bank ,Ranunculaceae and Leguminosae were dominant ,while the percentage of Cyperaceae and Gramineae were lower. The percentage of K. humilis seeds was relatively lower with 0. 97 % in green up stage and 1. 97 % in withering stage. The species composition of the seed bank correlated with that of the seed rain ( r = 0. 7505 , P < 0. 01) ,and there were 18 common species which was 78. 3 %of species of the seed bank. Only 41. 81 %of above-ground vegetation species presented in the seed bank. The seed numbers of the dominant plant species in vegetation were smaller , with lower percentage in the seed bank. Therefore , the dominant vegetation of K. humilis et al. mainly depended on vegetative reproduction to maintain and strengthen. From vegetation to the seed bank in green up stage ,the species diversity decreased by 9. 94 %. It implied that the seed bank was the source of vegetation regeneration , but also a mechanism of preserving species diversity of the plants.

Molecular phylogeny, recent radiation and evolution of gross morphology of the rhubarb genus Rheum (Polygonaceae) inferred from chloroplast DNA trnL-F sequences

Background and Aims Rheum, a highly diversified genus with about 60 species, is mainly confined to the mountainous and desert regions of the Qinghai-Tibetan plateau and adjacent areas. This genus represents a good example of the extensive diversification of the temperate genera in the Qinghai-Tibetan plateau, in which the forces to drive diversification remain unknown. To date, the infrageneric classification of Rheum has been mainly based on morphological characters. However, it may have been subject to convergent evolution under habitat pressure, and the systematic position of some sections are unclear, especially Sect. Globulosa, which has globular inflorescences, and Sect. Nobilia, which has semi-translucent bracts. Recent palynological research has found substantial contradictions between exine patterns and the current classification of Rheum. Two specific objectives of this research were (1) to evaluate possible relationships of some ambiguous sections with a unique morphology, and (2) to examine possible occurrence of the radiative speciation with low genetic divergence across the total genus and the correlation between the extensive diversification time of Rheum and past geographical events, especially the recent large-scale uplifts of the Qinghai-Tibetan Plateau.Methods The chloroplast DNA trnL-F region of 29 individuals representing 26 species of Rheum, belonging to seven out of eight sections, was sequenced and compared. The phylogenetic relationships were further constructed based on the sequences obtained.Key Results Despite the highly diversified morphology, the genetic variation in this DNA fragment is relatively low. The molecular phylogeny is highly inconsistent with gross morphology, pollen exine patterns and traditional classifications, except for identifying all samples of Sect. Palmata, three species of Sect. Spiciformia and a few species of Sect. Rheum as corresponding monophyletic groups. The monotypic Sect. Globulosa showed a tentative position within the clade comprising five species of Sect. Rheum. All of the analyses revealed the paraphyly of R. nobile and R. alexandrae, the only two species of Sect. Nobilia circumscribed by the possession of large bracts. The crude calibration of lineages based on trnL-F sequence differentiation implied an extensive diversification of Rheum within approx. 7 million years.Conclusions Based on these results, it is suggested that the rich geological and ecological diversity caused by the recent large-scale uplifts of the Qinghai-Tibetan Plateau since the late Tertiary, coupled with the oscillating climate of the Quaternary stage, might have promoted rapid speciation in small and isolated populations, as well as allowing the fixation of unique or rare morphological characters in Rheum. Such a rapid radiation, combined with introgressive hybridization and reticulate evolution, may have caused the transfer of cpDNA haplotypes between morphologically dissimilar species, and might account for the inconsistency between morphological classification and molecular phylogeny reported here.

三维物体识别及姿态测定的推理系统

本文介绍了三维物体识别及姿态测定的一种新技术，从物体空间域模型出发，通过约束推理及几何推理，在物体三维信息部分给定的条件下，推断预测图象模型，并通过实测的图象数据反馈，推断出隐含在图象中未给定的三维信息，最终实现三维物体识别及姿态测定。整个系统在ＶＩＣＯＭ机上用Ｃ语言完成。

博兴洼陷新生代构造-沉积演化及其对鲁西隆起的响应

The West Shandong Uplift and its adjacent basins, with same evolutional history before Mesozoic, are an important basin-orogenic systems in North China. After late Mesozoic, tectonic differentiation between basin and orogenic belt gradually displayed in the study area. The Boxing sag is a part of Jiyang Depression near to West Shandong Uplift, in which the whole Mesozoic and Cenozoic strata are preserved. Based on the analysis of sedimentary records in the Boxing sag, the Cenozoic structural and sedimentary evolutions in Boxing Sag and its response to Western Shandong uplift are discussed in this dissertation. The main conclusions in this research are presented as follows. Based on Seismic and well logging profile interpretation, fault growth index, thickness difference between bottom wall and top wall and fault activity rate from Eocene to Pliocene are studied. Boxing sag had three main faults, NE, NW and NEE trending faults. Research shows that the activity of the NW trending fault in the Boxing sag became weaken from E1-2S4 to N2m gradually. The evolution of NE and the NEE trending fault can be divided into three episodes, from E1-2k to E2s4, from E2s3 to E3s1, from N2m to E3d. The analysis of Paleogene samples of heavy mineral assemblages shows that metamorphic rocks represented by garnet, intermediate-acid igneous rocks represented by the assemblage of apatite, zircon and tourmaline became less from E1-2k to N2g, and sedimentary rocks represented by the assemblage of pyrite, barite and limonite also became less. Intermediate-basic igneous rocks represented by the assemblage of leucoxene, rutile and ilmenite and metamorphic rocks represented by epidote became more and more. Electronic microprobe analysis shows that glaucophane and barroisite are existed in Kongdian Formation and the 4th member of Shahejie Formation, and they demonstrate that Western Shandong and Eastern Shandong are all the source regions of the Boxing Sag, and they also indicate that oceanic crust existed before the collision between the Yangtze and North China continent. The fact that Eastern Shandong is the source region of Boxing Sag also indicates that Western Shandong was not high enough to prevent sediment from Eastern Shandong at E1-2k and E2s4. The results of the dating of five detrital zircons of Boxing Sag show Kongdian Formation and the 4th member of Shahejie Formation have the age peaks of 2800Ma and 700-800. It means that Eastern Shandong is the source region of Boxing Sag at early Paleogene and Western Shandong is not high enough to prevent the sediment from Eastern Shandong. The ages of 160-180 and 220-260 Ma, which exist in the Guantao Formation and Paleogene, are common in Eastern Shandong and rare in Western Shandong,and it implied that Western Shandong is a low uplift at 24Ma. The Paleogene strata have almost same age groups, while the Guantao Formation has significant variations of age groups, and this indicates that Boxing Sag and Western Shandong uplift had taken place tremendous changes. The results of apatite fission track in Boxing sag show that three times uplifts happened at the source region at 60 Ma, 45Ma and 15Ma respectively, and the Boxing sag experienced two subsidences at 60Ma, 45Ma and one uplift at 20Ma.

高温实验中重金属钼在硅酸盐熔体中的含量研究

This dissertation discusses current status of high temperature and high pressure and focuses on analyzing systematically the solubility of heavy metals in the silicate magma in HTHP experiments. The high temperature study on the content of heavy metal molybdenum in the silicate melts in this dissertation, which is granted, based on the geology mineralization model and the theory of HTHP experiments and combined with mineralization grade and geochemical nature of Mo, discusses the difference of mineralization between mantle plume and aqueous fluids and comes to the conclusions, which are as follows: (1) The content of Mo in the silicate melts is much greater than Mo mineralization grade. The molybdenum ore has the exploitation value when the industrial grade is higher than 0.06%. Mo content in different silicate melts varies because of the concentration of SiO2, that is, Mo content in the granodiorite is greater. (2) The content of Mo, which varies with reaction time, arises first and drops down in the alkali basalt melts, while variation is not too obvious in the granodiorite melts on the whole. (3) According to the picture of sample, the conclusion is not reached very well on some issues, such as the volatility and characteristic of molybdenum oxide and dependence on the geology environment.

胶东昆嵛山复式花岗岩体的演化—岩石学和锆石U-Pb年代学研究

Kunyushan composite granite pluton is located in northeast part of the Sulu UHP collisional belt, Jiaodong peninsula, eastern China. It is regarded as the boundary of the Jiaodong block and the Sulu UHP collisional belt. The body is unique in the Dabieshan-Sulu UHP collisional orogen for its feature of multiple intrusions of diverse types granitoid rocks in a long span after UHP the collision between the North China and the Yangtze plates in late Triassic. It can be grouped into four series on the basis of petrology and petrochemistry. They are mid-K calc-alkaline granitoids, strongly peraluminous granites, high-K calc-alkaline granitoids and syenitic granite of shoshonitic series. In this thesis, the later three types of rocks are investigated geochronologically in detail. The grain zircon U-Pb isotope dilution dating technique has been employed in this study. Zircon morphology are presented and discussion on the chemical and physical conditions of the granite formation have been carried out in addtion. Strongly peraluminous granites comprises foliated monzogranite and garnet bearing leucogranite. They occupy more than half of the area of the Kunyushan composite body. Three zircon samples of foliated monzogranites have been analyzed, they yield lower intercept ages mainly in the range of 140-150 Ma. The formation of these rocks was likely to be at 700-600 ℃, implied by zircon morphology. Two zircon samples of the garnet bearing leucogranite yield lower intercept ages from 130 Ma to 140 Ma. Zircon morphology indicate that the liquidus temperature of the magma was about 750 °C. Syenitic granite of shoshonitic series occur in the north central part of the body, and the volume is quite small contrast to other types. One zircon sample was chosen from this rock, and yield lower intercept age of 121+1.8/-2.1 Ma. Zircon morphology indicate that the liquidus temperature of this rock is up to 900 °C, which is much higher than others'. High-K calc-alkaline granitoids can be divided into two types on the basis of rock texture and structure. One is Kf-porphyritic monzogranite. It's outcrop is quite small. Zircon ages of one sample constrain the emplacement of this rock at about 112 Ma. The other is medium-grain to coarse-grain monzogranite. Zircons from it yield lower intercept age of 100.5+2.9/-4.6 Ma. The variation of zircon morphology suggest that these two monzogranites were outcomes of a single magma at different stage. The former emplaced earlier than the latter. The liquidus temperature of the magma was about 800 ℃ Inherited zircon is ubiquitous in the Kunyushan composite body. Most of the samples yield upper intercept ages of late Proterozoic. It was considered that only the Yangtze plate underwent a crustal growth during late Proterozoic among the two plates which involved into the UHP collision. Inherited zircon of about 200 Ma can also be observed in strongly peraluminous and high-K calc-alkaline granitoids. Two samples out of eight yield upper intercept ages of Achaean.

The ion-molecule reaction after multiphoton ionization in the binary cluster of ammonia and methanol

The binary cluster (CH3OH)(n)(NH3)(m) was studied by using a multiphoton ionization time-of-flight mass spectrometer (MPI-TOFMS). The measured two series of protonated cluster ions: (CH3OH)(n)H+ and (CH3OH)(n)NH4+ (1 less than or equal to n less than or equal to 14) were attributed to the ion-molecule reaction in the binary cluster ions. The mixed cluster of CH3OD with ammonia was also studied. The results implied that the proton transfer probability from the OD group was larger than that from CH3 group. The ab initio calculation of the binary cluster was carried out at the HF/STO-3G and MP2/6-31G** levels of theory, and indicated that the latter process of the proton transfer must overcome a barrier of similar to 29 kcal/mol. (C) 1999 Elsevier Science B.V. All rights reserved.

不同干扰条件下社会认知偏离者两半球协同功能研究

Previous studies have witnessed some psychological or behavioral deviation (such as aggressive behavior) might have an association with cerebral hemisphere cooperative dysfunction, however, it is still unclear whether there is an association between individuals with social cognitive bias and their hemispheric cooperative functions especially while the interhemisphere cooperative processing is under the conditions of emotional interferences. The purpose of this study is to explore the differences between the social cognitive bias group and the normal group’s interhemispheric cooperative functional activity under the conditions of with or without interferences. Methods: According to Dodge’s (1993) model of “social-cognitive mechanisms in the development of conduct disorder and depression”, a 51 items of “social cognitive bias scale” was created and was used to screen the high score group. 20 male subjects was composed of high score group and other 23 matched the control group. Stimulus tachistoscopically presented to the bilateral visual field and compared with the central. Both group’s interhemispheric cooperative functional activity were observed and compared under the conditions of without interference- i.e. base level and with the emotional interferences of white noise level and negative evaluative feedback speech level while finishing: experiment one: Chinese word-figure Stroop analogue task; experiment two: two single Chinese Characters combination task. Heart rate and respiratory rate were simultaneously recorded as index of emotional changes. Results: ① The high score group showed a decrease in processing accuracy compared with the normal group under the condition of white noise interference level in experiment one. ② Still under the condition of white noise interference level, there were more reaction time and more errors were observed in high score group than normal in experiment two. ③ Both groups showed speed up effect and the strategic processing tendency of speed-accuracy trade-off effect under the condition of white noise interference level in both experiments. ④ Between group differences of interhemipheric cooperative function were not observed under the conditions of base level and the negative evaluative feedback speech level within both experiments. Conclusion: The results suggested that interhemispheric cooperative functional differences exists between the two groups, characterized as ① differences existed in interhemispheric cooperative processing strategy between the two groups, with the high score group presented “hierarchic” deficiency strategy. ② the appearance of the differences between the two groups were condition specified , and in this research it was only under the white noise interference condition. ③ the features of the differences between the two groups were the differences on multidimensional performances and with a deficit orientation in high score group. ④ the varieties of the differences were changing with cooperative tasks, as in this research the high score group performed worse in complementary cooperative task. In addition, both group adjusted the processing strategy respectively under the condition of white noise evoked emotional interference implied that the interaction between the interhemisphere cooperative processing and emotion might exist.

投射性空间关系表达过程的研究

It is easy to find that, in each language, the terms and phrases for the representation of spatial locating and orientation, and the ways for sharing spatial knowledge are very rich. The basic way of sharing spatial information is mapping our experience and actions with the environment by using terms and utterances that represent spatial relations. How to build the mapping relation among them and what factors affect the process of mapping are the questions need to be answered in this study. The whole course of expressing projective spatial relation includes the verbal expression and perception to the projective spatial relation. In experiment 1, the perceptual characteristics of perceiving the projective spatial relation was studied by analyzing the production latencies from the presentation of the stimulators in different directions (at 5 levels: 00, 22.50, 450, 67.50, and 900) to the onset of the corresponding buttons triggering on the keyboard, the study verifies the results of prior researches and revealed the foundation of expressing the projective spatial relation. In the experiment 2, and 3, the way and the role of the verbal expression were investigated. Subjects were asked to speak out the spatial relation between intended object and reference object by using verbal locative expressions. In experiment 2, Chinese was used as the verbal expression way, and in Experiment 3, English instead. Experiment 4 was similar as experiment 3, but time of voice key triggering was controlled and balanced among trials to verify the results of Experiment 3 further. Experiment 5 investigated the effect of pre-cue on the courses of expressing projective spatial relation. There were two kinds of clues, one was the spatial locative utterances, and the other was the perceptual coordinates framework, such as drawing a cross ”+” in a circle to imply four quadrants. The main conclusions of this research were as follows: 1. When speaking out a spatial relation, different sets of spatial terms, such as “left and right”, or “north and south”, affected the speed of verbal expression. Verbal coding process was affected by how well the perceptual salient direction matched with spatial terms, which made the speed of verbal expression different. 2. When using composite spatial terms to express diagonal directions, people tend to use direct mapping from spatial conceptual representation to composite spatial terms, rather than combining the two axes, which implied there existed direct one-on-one mapping between spatial conceptual representation and spatial terms. But during specific developing period, the way of combining two axes was employed as well for spatial expression, which meant perceptual salient directions played critical role in the process of perceiving and expressing projective spatial relations. 3. The process of verbal expression of the projective spatial relation was improved by the familiarity of spatial utterances, but this improvement was not the results of enhancement of the effect of prototypical diagonal direction.

空间及言语工作记忆任务的情绪效应：来自ERP/ fMRI的证据

In the present study, based on processing efficiency theory, we used the event-related potentials (ERP) and functional magnetic resonance image (fMRI) techniques to explore the underlying neutral mechanism of influences of negative emotion on three subsystems of working memory, phonological loop、 visuospatial sketh pad and the central executive. The modified DSMT (delayed matching-to-sample task) and n-back tasks were adopted and IAPS (International Affective Picture System) pictures were employed to induce the expected emotional state of subjects. The main results and conclusions obtained in the series of experiments are as the following: 1. In DSM tasks, we found P200 and P300 were reduced by negative emotion in both spatial and verbal tasks, however the increased negative slow wave were only observed in spatial tasks, not in verbal tasks. 2. In n-back tasks, the updating function of WM associated P300 was affected by negative emotion only in spatial tasks, not in verbal tasks. Current density analysis revealed strong current density in the fronto-parietal cortex only in the spatial tasks as well. 3. We adopted fMRI-block design and ROIs analysis, and found significant emotion and task effects in spatial WM-associated right superior parietal cortex; only emotion effect in verbal WM-associated Broca’s area; the interaction effect in attention-associated medial prefrontal area and bilateral inferior parietal cortex. These results implied the negative emotion mainly disturbed the spatial WM-related areas, and the attention control system play a key role in the interaction of spatial WM and negative emotion. 4. to further examine the effects of positive、negative and neutral emotion on tasks with different cognitive loads, the selective effect of emotion on the ERP components of spatial WM was only found in 2-back tasks, not in visual searching tasks. So, firstly the positive emotion as well as negative emotion selectively disturbed on spatial WM in light of the attention resource competition mechanism. Secondly, the selective influences based on the different WM systems, not the properties of spatial and verbal information. At last, the manner of the interaction of emotion and cognition is correlated with the cognitive load.

工作幸福感的结构、测量及作用机制

With the emergence and development of positive psychology, happiness has been the focus of academia and business. However, there is no uniform measure of happiness, because of many different theories of happiness, which are not compatible with others. It bounds the further development of happiness theory. It is also the same with the research of work well-being, which refers to the emotional experience and quality of psychological functioning of employee in the workplace. Subjective well-being (SWB) and psychological well-being (PWB) are two major theories of happiness. Prior research has demonstrated the integration of these two theories theoretically, but still needs more empirical support. Besides, in line with the development of positive psychology, a body of knowledge about positive leadership is advocated. Transformational leadership is treated as one kind of positive leadership, since it emphasizes the leader’s motivational and elevating effect on followers. But the extent to which the transformational leadership can enhance work well-being, and what the mechanism is, these are the questions need to be explored. Based on the integration of SWB and PWB, this research tried to investigate the structure, measurement and mechanism of work well-being, and combining with the theory of transformational leadership, this study also tried to investigate the relationship between transformational leadership and work well-being. The structure and measurement of work well-being, the relationships between work well-being and job characteristics (including job resources and job demands), the relationships among transformational leadership, job resources, work well-being and corresponding outcomes, the relationships among transformational leadership, job demands, work well-being and corresponding outcomes, and the relationships among transformational leadership, group job characteristics, group work well-being and corresponding group outcomes were explored by using content analysis, Subject Matter Experts (SMEs) discussion, and structural questionnaire surveys. More than 7000 subjects were surveyed, and Explore Factor Analysis (EFA), Confirm Factor Analysis (CFA), Structural Equation Modeling (SEM), Hierarchical Linear Modeling (HLM) and other statistics methods were used. The following is the major conclusions. Firstly, work well-being is a two high-order factors structure, which includes affective well-being (AWB) and cognitive well-being (CWB). AWB is similar to SWB, and CWB is similar to PWB. Besides, the construct of AWB includes sub-dimensions of positive emotional experience and negative emotional experience. And the construct of CWB consists of work autonomy, personal growth, work competent, and work significance. Secondly, the relationships between job characteristics and AWB and CWB are different. On one hand job demands are directly related to AWB, and are indirectly related to CWB through the full mediation of AWB, on the other job resources are directly related to CWB, and are indirectly related to AWB through the full mediation of CWB, which means AWB and CWB reciprocally influences each other in the model of job demands-resources. These results were concluded as the process model of work well-being. Thirdly, AWB and CWB are positively related to many workplace outcomes, including job satisfaction, group satisfaction, organizational commitment, turnover intention, job performance, organizational citizenship behavior (OCB), and general psychological health and general physiological health. Fourthly, transformational leadership is indirectly related to CWB through the full mediation of job resources, and is related to AWB through the partial mediation of job demands. Meanwhile, transformational leadership is related to many workplace outcomes through the mediation of job characteristics and work well-being. These results implied that transformational leadership is indeed one kind of positive leadership. Fifthly, in the group level, transformational leadership is indirectly related to group CWB through the full mediation of group job resources, and is related to group AWB through the full mediation of group job demands. Group AWB has positive influence on group CWB, but not vice versa. Group job characteristics and group work well-being fully mediate the relationships between transformational leadership and intragroup cooperation and group performance.

(Semi-)Predictive Discretization During Model Selection

In this paper, we present an approach to discretizing multivariate continuous data while learning the structure of a graphical model. We derive the joint scoring function from the principle of predictive accuracy, which inherently ensures the optimal trade-off between goodness of fit and model complexity (including the number of discretization levels). Using the so-called finest grid implied by the data, our scoring function depends only on the number of data points in the various discretization levels. Not only can it be computed efficiently, but it is also independent of the metric used in the continuous space. Our experiments with gene expression data show that discretization plays a crucial role regarding the resulting network structure.