The authors examine the motivational determinants of interfirm alliance behavior through the sociocognitive principle of regulatory focus, with particular reference to the role of opportunism at the ...formation, operation, and outcome stages of alliance development. Regulatory focus pertains to whether an organization engages with the external world to achieve positive outcomes (promotion focus) or to avoid negative outcomes (prevention focus). The authors believe that the motivational orientations of the alliancing firms play key roles in shaping tolerance for opportunism, and they argue, broadly, that alliance firms with a promotion regulatory focus will be more tolerant of their partners’ opportunistic behavior than alliance firms with a prevention regulatory focus. Propositions are developed regarding the linkages between the regulatory focus of an alliance firm and its sensitivity to partner opportunism in the different stages of alliance development. The authors discuss further research directions and the managerial implications of their analysis.
Glutathione GSH is a major intracellular antioxidant that disposes peroxides and protects neurons and glial cells from oxidative stress. In both schizophrenia and bipolar disorder, atypical levels of ...GSH have been demonstrated, particularly in the anterior cingulate cortex (ACC), though no consistent results have emerged due to limitations in sample size. Our objective was to evaluate if GSH levels in the ACC are abnormal in these 2 disorder, when compared to healthy controls.
We reviewed all 1H-MRS studies reporting GSH values for patients satisfying DSM or ICD based criteria for (1) the psychotic disorders - schizophrenia or schizoaffective disorder or (2) bipolar disorder in comparison to a healthy controls (HC) group in the Anterior Cingulate Cortex (ACC) published until June 2018. A random-effects model was used to calculate the pooled effect size. A meta-regression analysis of moderator variables was also undertaken.
The literature search identified 18 studies with a total sample size of 581 controls, 578 patients with schizophrenia or bipolar disorder. There is a small but significant reduction in ACC GSH in patients with schizophrenia compared to HC (N = 13; RFX SMD =0.26; 95% CI 0.07 to 0.44; p = 0.008; heterogeneity p = 0.11). There is a significant increase in the ACC GSH concentration in bipolar disorder compared to HC (N = 6; RFX SMD = −0.28, 95% CI −0.09 to −0.47; p = 0.003; heterogeneity p = 0.95).
We report a small, but significant reduction in GSH concentration in the ACC in schizophrenia, and a similar sized increase in bipolar disorder. A notable limitation is the lack of sufficient data to examine the moderating effect of the symptom profile. Schizophrenia and bipolar disorder have notably different patterns of redox abnormalities in the ACC. Reduced ACC GSH may confer a schizophrenia-like clinical phenotype, while an excess favouring a bipolar disorder-like profile.
•Anterior cingulate glutathione is elevated in bipolar disorder but reduced in schizophrenia.•Divergent mechanisms may operate on the cortical antioxidant system in these 2 disorders.•There are no head-to-head comparisons of cortical GSH to date in these 2 disorders.
The resource-based view of the firm has not been systematically applied to strategic alliances. By examining the role of firm resources in strategic alliances, we attempt, in this paper, to put ...forward a general resource-based theory of strategic alliances, synthesizing the various findings in the literature on alliances from a resource-based view. The proposed theory covers four major aspects of strategic alliances: rationale, formation, structural preferences, and performance. The resource-based view suggests that the rationale for alliances is the value-creation potential of firm resources that are pooled together. We note that certain resource characteristics, such as imperfect mobility, imitability, and substitutability, promise accentuated value-creation, and thus facilitate alliance formation. We discuss how the resource profiles of partner firms would determine their structural preferences in terms of four major categories of alliances: equity joint ventures, minority equity alliances, bilateral contract-based alliances, and unilateral contract-based alliances. As part of the theory, we propose a typology of inter-partner resource alignment based on the two dimensions of resource similarity and resource utilization, yielding four types of alignment: supplementary, surplus, complementary, and wasteful. We also discuss how partner resource alignment directly affects collective strengths and inter-firm conflicts in alliances, which in turn contribute to alliance performance. Finally, we develop a number of propositions to facilitate empirical testing of the theoretical framework, suggest ways to carry out this testing, indicate future research directions, and list some of the more significant managerial implications of the framework.
•We studied conservation agriculture (CA) impacts on root water uptake (RWU) by cotton.•Potential transpiration rates under conventional tillage were lower than for CA.•RWU by cotton in the permanent ...broad bed plots with residue was higher than for CA.•Higher RWU under CA was due to better root growth and more radiation interception.•Hydrus-2D can simulate temporal changes in soil water contents.
Although soil conservation practices are being promoted as better environmental protection technologies than traditional farmers’ practice, limited information is available on how these practices affect soil water balance and root water uptake. The root water uptake (RWU) patterns of cotton grown under soil conservation practices and soil water balance in cotton (Gossypium hirsutum L.) fieldsunder a cotton-wheat (Triticum aestivum L.) cropping system were analyzed using the Hydrus-2D model. The treatments were: conventional tillage (CT), zero tillage (ZT), permanent narrow beds (PNB), permanent broad beds (PBB), ZT with residue (ZT+R), PNB with residue (PNB+R) and PBB with residue (PBB+R). Results in the third year of the cotton crop indicated that the surface (0–15cm layer) field saturated hydraulic conductivity in both PNB and PBB plots were similar and were significantly higher than in the ZT plots. Computed potential transpiration rates (Trp) under CT were lower than in other treatments, due to less radiation interception and lower Leaf Area Index (LAI). Both PNB and PBB plots had higher Trp and crop yields than CT plots, which were further improved by residue retention. Predicted soil water content (SWC) patterns during the simulation periods of third and fourth years showed strong correlation (R2=0.88, n=105, P<0.001, the root mean square error (RMSE)=0.025, and the average relative error (AVE)=7.5% for the third year and R2=0.81, n=105, P<0.001, RMSE=0.021, and AVE=9% for the fourth year) with the actual field measured SWCs. Cumulative RWU (mm) were in the order: ZT (143)<CT (157)<PNB (163)<ZT+R (174)<PBB (188)<PNB+R (198)<PBB+R (226). Thus, PBB+R and PNB+R practices could be adopted for cotton cultivation, as these enhanced root growth and improved radiation interception and LAI. The Hydrus-2D model may be adopted for managing efficient water use, as it can simulate the temporal changes in SWC and actual transpiration rates of a crop/cropping system.
We develop a social exchange perspective of alliance constellations, emphasizing the role of generalized exchanges. We then discuss three social control mechanisms for mitigating the unique ...difficulties of managing constellations, and we conclude by proposing a typology of constellations based on the dimensions of exchange horizon and type of generalized reciprocity. The perspective presented here contributes not only to research on alliances but also to the larger body of literature on generalized social exchange processes, which has traditionally been centered on interpersonal relations.
To understand role of mitochondrial (mt) mutations in genes regulating oxidative phosphorylation (OXPHOS) in pathogenesis of male infertility. Infertility affects approximately 15% of couples trying ...to conceive. Infertility is frequently attributed to defects of sperm motility and number. Mitochondrion and mitochondrial DNA (mtDNA) play an important role in variety of physiological process. They control the oxidative energy supply and thus are central to growth, development and differentiation. Mitochondrial function is controlled by a fine-tuned crosstalk between mtDNA and nuclear DNA (nDNA). As mitochondria supply energy by OXPHOS, any mutation in mtDNA disrupts adenosine triphosphate (ATP) production and thus result in an impaired spermatogenesis and impaired flagellar movement. As sperm midpiece has few mtDNA copies, thus enhanced number of mutant mtDNA results in early phenotypic defect which manifest as spermatogenic arrest or asthenozoospermia. Oxidative stress and mtDNA mutations are positively correlated and mutations in mitochondrial genome (mt genome) are implicated in the lowered fertilising capacity of the sperm and affects the reproductive potential of an individual.
A thorough review of articles in the last 15 years was cited with reference to the below-mentioned keywords. The articles considered discuss the role of mt genome in the normal functioning of sperm and the factors associated with mt mutations and impact of these mutations on the reproductive potential.
Sperm motility is a very important factor for the fertilisation of ova. The energy requirements of sperm are therefore very critical for sperm. Mutations in the mitochondrial genes as COX II, ATPase 6 and 8 play an important role and disrupts ATP production affecting the spermatogenesis and sperm motility. Therefore, the aberrations in mt genome are an important etiopatholgy of male infertility.
In the context of male infertility, mt mutations, generation of reactive oxygen species and lowered antioxidant capacity are interlinked and constitute a unified pathogenic molecular mechanism. In the era of assisted reproduction technique (ART), it is very important to distinguish between mutations in nuclear and mitochondrial genomes in sperm, as mtDNA mutations are better diagnostic and prognostic markers in infertile men opting for ART.
The troubling potential for opportunistic behaviour in strategic alliances is acknowledged in both research and practice, and yet the antecedents of such opportunism remain largely unexplored in the ...literature. In this article we suggest that the inherent temporalities of alliances play significant roles in partner opportunism. We propose a model of potential partner opportunism that assigns antecedent and contingent roles to the temporal horizons of alliances and the temporal orientations of the member firms. We introduce the notion of alliance horizons and suggest that they are constituted by the temporal orientations of the member firms and a number of common alliance formation factors. We also discuss how these alliance horizons in conjunction with the temporal orientations of member firms result in different levels of potential opportunism. Lastly, we develop a number of propositions to facilitate empirical research on the temporal contingencies of partner opportunism and indicate directions for further studies.
The instabilities of strategic alliances have been examined in the literature through a number of theoretical approaches. Alliance instabilities refer to major changes or dissolutions of alliances ...that are unplanned from the perspective of one or more partners. Although the literature identifies certain characteristics of strategic alliances that may lead to their unplanned dissolution, the extent of our understanding of this subject appears to be fragmented and incomplete. In this article we propose a comprehensive framework for adequately understanding alliance instabilities based on the notion of internal tensions. We suggest that strategic alliances are sites in which conflicting forces develop and which can be viewed as being constituted by three key pairs of competing forces—namely, cooperation versus competition, rigidity versus flexibility, and short-term versus long-term orientation. This tensions framework helps us in explaining the intrinsic vulnerability of alliances in terms of a wide range of internal contradictions and enables us to examine, in an integrated manner, the incidence, dynamics, and eventual dissipation of the inherent instabilities. We discuss the interrelationships among the different internal tensions and their impacts on different types of strategic alliances. We also examine the termination of alliances through mergers/acquisitions and dissolution. Finally, we suggest ways to empirically test the various ideas and propositions developed here and indicate directions for further research.
Temperature programmed reduction (TPR) and hydrogen chemisorption combined with reoxidation measurements were used to define the reducibility of supported cobalt catalysts. Different supports (e.g. ...Al
2O
3, TiO
2, SiO
2, and ZrO
2 modified SiO
2 or Al
2O
3) and a variety of promoters, including noble metals and metal cations, were examined. Significant support interactions on the reduction of cobalt oxide species were observed in the order Al
2O
3>TiO
2>SiO
2. Addition of Ru and Pt exhibited a similar catalytic effect by decreasing the reduction temperature of cobalt oxide species, and for Co species where a significant surface interaction with the support was present, while Re impacted mainly the reduction of Co species interacting with the support. For catalysts reduced at the same temperature, a slight decrease in cluster size was observed in H
2 chemisorption/pulse reoxidation with noble metal promotion, indicating that the promoter aided in reducing smaller Co species that interacted with the support. On the other hand, addition of non-reducible metal oxides such as B, La, Zr, and K was found to cause the reduction temperature of Co species to shift to higher temperatures, resulting in a decrease in the percentage reduction. For both Al
2O
3 and SiO
2, modifying the support with Zr was found to enhance the dispersion. Increasing the cobalt loading, and therefore the average Co cluster size, resulted in improvements to the percentage reduction. Finally, a slurry phase impregnation method led to improvements in the reduction profile of Co/Al
2O
3.
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