949 resultados para Different effects


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Principal Topic Although corporate entrepreneurship is of vital importance for long-term firm survival and growth (Zahra and Covin, 1995), researchers still struggle with understanding how to manage corporate entrepreneurship activities. Corporate entrepreneurship consists of three parts: innovation, venturing, and renewal processes (Guth and Ginsberg, 1990). Innovation refers to the development of new products, venturing to the creation of new businesses, and renewal to redefining existing businesses (Sharma, and Chrisman, 1999; Verbeke et al., 2007). Although there are many studies focusing on one of these aspects (cf. Burgelman, 1985; Huff et al., 1992), it is very difficult to compare the outcomes of these studies due to differences in contexts, measures, and methodologies. This is a significant lack in our understanding of CE, as firms engage in all three aspects of CE, making it important to compare managerial and organizational antecedents of innovation, venturing and renewal processes. Because factors that may enhance venturing activities may simultaneously inhibit renewal activities. The limited studies that did empirically compare the individual dimensions (cf. Zahra, 1996; Zahra et al., 2000; Yiu and Lau, 2008; Yiu et al., 2007) generally failed to provide a systematic explanation for potential different effects of organizational antecedents on innovation, venturing, and renewal. With this study we aim to investigate the different effects of structural separation and social capital on corporate entrepreneurship activities. The access to existing and the development of new knowledge has been deemed of critical importance in CE-activities (Floyd and Wooldridge, 1999; Covin and Miles, 2007; Katila and Ahuja, 2002). Developing new knowledge can be facilitated by structurally separating corporate entrepreneurial units from mainstream units (cf. Burgelman, 1983; Hill and Rothaermel, 2003; O'Reilly and Tushman, 2004). Existing knowledge and resources are available through networks of social relationships, defined as social capital (Nahapiet and Ghoshal, 1998; Yiu and Lau, 2008). Although social capital has primarily been studied at the organizational level, it might be equally important at top management level (Belliveau et al., 1996). However, little is known about the joint effects of structural separation and integrative mechanisms to provide access to social capital on corporate entrepreneurship. Could these integrative mechanisms for example connect the separated units to facilitate both knowledge creation and sharing? Do these effects differ for innovation, venturing, and renewal processes? Are the effects different for organizational versus top management team integration mechanisms? Corporate entrepreneurship activities have for example been suggested to take place at different levels. Whereas innovation is suggested to be a more bottom-up process, strategic renewal is a more top-down process (Floyd and Lane, 2000; Volberda et al., 2001). Corporate venturing is also a more bottom-up process, but due to the greater required resource commitments relative to innovation, it ventures need to be approved by top management (Burgelman, 1983). As such we will explore the following key research question in this paper: How do social capital and structural separation on organizational and TMT level differentially influence innovation, venturing, and renewal processes? Methodology/Key Propositions We investigated our hypotheses on a final sample of 240 companies in a variety of industries in the Netherlands. All our measures were validated in previous studies. We targeted a second respondent in each firm to reduce problems with single-rater data (James et al., 1984). We separated the measurement of the independent and the dependent variables in two surveys to create a one-year time lag and reduce potential common method bias (Podsakoff et al., 2003). Results and Implications Consistent with our hypotheses, our results show that configurations of structural separation and integrative mechanisms have different effects on the three aspects of corporate entrepreneurship. Innovation was affected by organizational level mechanisms, renewal by integrative mechanisms on top management team level and venturing by mechanisms on both levels. Surprisingly, our results indicated that integrative mechanisms on top management team level had negative effects on corporate entrepreneurship activities. We believe this paper makes two significant contributions. First, we provide more insight in what the effects of ambidextrous organizational forms (i.e. combinations of differentiation and integration mechanisms) are on venturing, innovation and renewal processes. Our findings show that more valuable insights can be gained by comparing the individual parts of corporate entrepreneurship instead of focusing on the whole. Second, we deliver insights in how management can create a facilitative organizational context for these corporate entrepreneurship activities.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The human-induced rise in atmospheric carbon dioxide since the industrial revolution has led to increasing oceanic carbon uptake and changes in seawater carbonate chemistry, resulting in lowering of surface water pH. In this study we investigated the effect of increasing CO2 partial pressure (pCO2) on concentrations of volatile biogenic dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP), through monoculture studies and community pCO2 perturbation. DMS is a climatically important gas produced by many marine algae: it transfers sulfur into the atmosphere and is a major influence on biogeochemical climate regulation through breakdown to sulfate and formation of subsequent cloud condensation nuclei (CCN). Overall, production of DMS and DMSP by the coccolithophore Emiliania huxleyi strain RCC1229 was unaffected by growth at 900 matm pCO2, but DMSP production normalised to cell volume was 12% lower at the higher pCO2 treatment. These cultures were compared with community DMS and DMSP production during an elevated pCO2 mesocosm experiment with the aim of studying E. huxleyi in the natural environment. Results contrasted with the culture experiments and showed reductions in community DMS and DMSP concentrations of up to 60 and 32% respectively at pCO2 up to 3000 matm, with changes attributed to poorer growth of DMSP-producing nanophytoplankton species, including E. huxleyi, and potentially increased microbial consumption of DMSand dissolvedDMSPat higher pCO2.DMSandDMSPproduction differences between culture and community likely arise from pH affecting the inter-species responses between microbial producers and consumers.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Protein, generally agreed to be the most satiating macronutrient, may differ in its effects on appetite depending on the protein source and variation in digestion and absorption. We investigated the effects of two milk protein types, casein and whey, on food intake and subjective ratings of hunger and fullness, and on postprandial metabolite and gastrointestinal hormone responses. Two studies were undertaken. The first study showed that energy intake from a buffet meal ad libitum was significantly less 90 min after a 1700 kJ liquid preload containing 48 g whey, compared with an equivalent casein preload (P<0.05). In the second study, the same whey preload led to a 28 % increase in postprandial plasma amino acid concentrations over 3 h compared with casein (incremental area under the curve (iAUC), P<0.05). Plasma cholecystokinin (CCK) was increased by 60 % (iAUC, P<0.005), glucagon-like peptide (GLP)-1 by 65 % (iAUC, P<0.05) and glucose-dependent insulinotropic polypeptide by 36 % (iAUC, P<0.01) following the whey preload compared with the casein. Gastric emptying was influenced by protein type as evidenced by differing plasma paracetamol profiles with the two preloads. Greater subjective satiety followed the whey test meal (P<0.05). These results implicate post-absorptive increases in plasma amino acids together with both CCK and GLP-1 as potential mediators of the increased satiety response to whey and emphasise the importance of considering the impact of protein type on the appetite response to a mixed meal.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The GPR30, a former orphan GPCR, is a putative membrane estrogen receptor that can activate rapid signaling pathways such as extracellular regulated kinase (ERK) in a variety of cells and may contribute to estrogen's effects in the central nervous system. The distribution of GPR30 in the limbic system predicts a role for this receptor in the regulation of learning and memory and anxiety by estrogens. Though acute G-1 treatment is reported to be anxiogenic in ovariectomised female mice and in gonadally intact male mice, the effect of GPR30 activation is unknown in gonadectomised male mice. In this study, we show that an acute administration of G-1 to gonadectomised male mice, but not female mice, was anxiolytic on an elevated plus maze task, without affecting locomotor activity. In addition, though G-1 treatment did not regulate ERK, it was associated with increased estrogen receptor (ER)alpha phosphorylation in the ventral, but not dorsal, hippocampus of males. In the female, G-1 increased the ERK activation solely in the dorsal hippocampus, independent of state anxiety. This is the first study to report an anxiolytic effect of GPR30 activation in male mice, in a rapid time frame that is commensurate with non-genomic signaling by estrogen.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Hypertonic NaCl intake is produced by serotonin receptor antagonism in the lateral parabrachial nucleus (LPBN) of dehydrated rats or in rats pretreated with a mineralocorticoid, for example deoxycorticosterone (DOCA), that receive an intracerebroventricular injection (icv) of angiotensin II (ang II). The objective of the present work was to find out whether these two mechanisms are also involved with isotonic NaCl intake. Serotonin receptor blockade by methysergide in the LPBN (4 mu g/0.2 mu l bilaterally) had no effect on 0.15 M NaCl (methysergide: 19.3 +/- 5.2 ml/60 min; vehicle: 19.3 +/- 4.2 ml/60 min; n=7) or water (methysergide: 3.4 +/- 1.4 ml/ 60 min; vehicle 2.2 +/- 0.6 ml/60 min) intake induced by systemic diuretic furosemide combined with low dose of captopril (Furo/Cap). Methysergide treatment 4 days later in the same animals produced the expected enhancement in the 0.3 M NaCl intake induced by Furo/Cap (methysergide: 16.6 +/- 3.5 ml/60 min; vehicle: 6.6 +/- 1.5 ml/60 min). Similar result was obtained when another group was tested first with 0.3 M NaCl and later with 0.15 M NaCl. Isotonic NaCl intake induced by icv ang II was however enhanced by prior DOCA treatment. A de novo hypertonic NaCl intake was produced in another group by the same combined treatment. The results suggest that a facilitatory mechanism like the mineralocorticoid/ang II synergy may enhance NaCl solution intake at different levels of tonicity, while the action of an inhibitory mechanism, like the LPBN serotonergic system, is restricted to the ingestion at hypertonic levels. (c) 2007 Elsevier B.V. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Cardiovascular responses to central losartan (LOS), a non-peptide angiotensin II (ANG II) receptor antagonist, were investigated by comparing the effects of LOS injection into the 3rd and 4th cerebral ventricles (3rdV, 4thV) on mean arterial pressure (MAP) and heart rate (HR). Adult male Holtzman rats were used (N = 6 animals per group). Average basal MAP and HR were 114 +/- 3 mmHg and 343 +/- 9 bpm (N = 23), respectively. LOS (50, 100 or 200 nmol/2 mu l) injected into the 3rdV induced presser (peak of 25 +/- 3 mmHg) and tachycardic (peak of 60 +/- 25 bpm) responses. LOS injected into the 4thV had no effect on MAP, but it induced bradycardia (peak of -35 +/- 15 bpm). KCl (200 nmol/2 mu l) injected into the 3rdV or into the 4thV had no effect on either MAP or HR compared to 0.9% saline injection. The results indicate that LOS injected into the third ventricle acts on forebrain structures to induce its presser and tachycardic effects and that bradycardia, likely dependent on hindbrain structures, is obtained when LOS is injected into the fourth ventricle.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Cardiovascular responses to central losartan (LOS), a non-peptide angiotensin II (ANG II) receptor antagonist, were investigated by comparing the effects of LOS injection into the 3rd and 4th cerebral ventricles (3rdV, 4thV) on mean arterial pressure (MAP) and heart rate (HR). Adult male Holtzman rats were used (N=6 animals per group). Average basal MAP and HR were 114±3 mmHg and 343±9 bpm (N=23), respectively. LOS (50, 100 or 200 nmol/2 μl) injected into the 3rdV induced pressor (peak of 25±3 mmHg) and tachycardic (peak of 60±25 bpm) responses. LOS injected into the 4thV had no effect on MAP, but it induced bradycardia (peak of -35±15 bpm). KCl (200 nmol/2 μl) injected into the 3rdV or into the 4thV had no effect on either MAP or HR compared to 0.9% saline injection. The results indicate that LOS injected into the third ventricle acts on forebrain structures to induce its pressor and tachycardic effects and that bradycardia, likely dependent on hindbrain structures, is obtained when LOS is injected into the fourth ventricle.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Substances that mimic endogenous hormones may alter the cell signaling that govern prostate development and predispose it to developing lesions in adult and senile life. Bisphenol A is able to mimic estrogens, and studies have demonstrated that low levels of exposure to this compound have caused alterations during prostate development. The aim of this study was to describe the prostate development in both male and female neonatal gerbils in normal conditions and under exposure to BPA during intrauterine life, and also to analyze whether the effects of intrauterine exposure to BPA remain in adulthood. Morphological, stereological, three-dimensional reconstruction, and immunohistochemical methods were employed. The results demonstrated that in 1-day-old normal gerbils, the female paraurethral glands and the male ventral lobe are morphologically similar, although its tissue components-epithelial buds (EB), periurethral mesenchyme (PeM), paraurethral mesenchyme (PaM) or ventral mesenchymal pad (VMP), and smooth muscle (SM)-have presented different immunolabeling pattern for androgen receptor (AR), and for proliferating cell nuclear antigen (PCNA). Moreover, we observed a differential response of male and female prostate to intrauterine BPA exposure. In 1-day-old males, the intrauterine exposure to BPA caused a decrease of AR-positive cells in the PeM and SM, and a decrease of the proliferative status in the EB. In contrast, no morphological alterations were observed in ventral prostate of adult males. In 1-day-old females, BPA exposure promoted an increase of estrogen receptor alpha (ERα) positive cells in PeM and PaM, a decrease of AR-positive cells in EB and PeM, besides a reduction of cell proliferation in EB. Additionally, the adult female prostate of BPA-exposed animals presented an increase of AR- and PCNA-positive cells. These results suggest that the prostate of female gerbils were more susceptible to the intrauterine BPA effects, since they became more proliferative in adult life. © 2015 Wiley Periodicals, Inc. Environ Toxicol, 2015.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The plastic brain responses generated by the training with acrobatic exercise (AE) and with treadmill exercise (TE) may be different. We evaluated the protein expression of synapsin I (SYS), synaptophysin (SYP), microtubule-associated protein 2 (MAP2) and neurofilaments (NF) by immunohistochemistry and Western blotting in the motor cortex, striatum and cerebellum of rats subjected to TE and AE. Young adult male Wistar rats were divided into 3 groups: sedentary (Sed) (n=15), TE (n=20) and AE (n=20). The rats were trained 3 days/week for 4 weeks on a treadmill at 0.6 km/h, 40 min/day (TE), or moved through a circuit of obstacles 5 times/day (AE). The rats from the TE group exhibited a significant increase of SYS and SYP in the motor cortex, of NF68, SYS and SYP in the striatum, and of MAP2, NF and SYS in the cerebellum, whereas NF was decreased in the motor cortex and the molecular layer of the cerebellar cortex. On the other hand, the rats from the AE group showed a significant increase of MAP2 and SYP in the motor cortex, of all four proteins in the striatum, and of SYS in the cerebellum. In conclusion, AE induced changes in the expression of synaptic and structural proteins mainly in the motor cortex and striatum, which may underlie part of the learning of complex motor tasks. TE, on the other hand, promoted more robust changes of structural proteins in all three regions, especially in the cerebellum, which is involved in learned and automatic tasks. (C) 2012 Elsevier B.V. All rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Reported effects of cyclosporin A (Sandimmun, CsA) on bone have been both contradictory and controversial. Thus, stimulation of new bone formation as well as increased mineral and matrix resorption have been observed. To investigate the response of basal mineral and matrix turnover to CsA treatment at different stages of skeletal development, comparative experiments were conducted in young growing female rats and in adults. Fifty-six young animals (study A) and 40 adults (study B) received orally either the carrier substance or 5, 15, and 30 mg/kg CsA for 30 days. The following parameters were measured: (a) total skeletal mineral content by dual energy X-ray absorptiometry (DEXA) on days 1 and 30; (b) tibial trabecular volume at day 30; (c) serum osteocalcin at 5-day intervals; (d) urinary deoxypyridinoline (Dpd) excretion (days 1, 15, and 30); and (e) plasma levels of CsA. Results can be summarized as follows: in young rats (study A), total skeletal mineral was not modified by the 5- and 15-mg/kg doses of CsA, whereas 30 mg/kg induced a significant decrease (-15%, p < 0.01). This parameter was not significantly modified in adult animals (study B) subjected to the same doses. The administration of 5 mg/kg CsA did not alter tibial trabecular volume in young rats, but 15 and 30 mg/kg significantly lowered this parameter (-16.3%, p < 0.02, and -42%, p < 0.001, respectively). In adult rats, tibial trabecular volume remained unchanged with the exception of the group receiving 30 mg/kg which exhibited significantly lower values (-28%, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Relevância:

100.00% 100.00%

Publicador:

Resumo:

For perceptual-cognitive skill training, a variety of intervention methods has been proposed, including the so-called “color-cueing method” which aims on superior gaze-path learning by applying visual markers. However, recent findings challenge this method, especially, with regards to its actual effects on gaze behavior. Consequently, after a preparatory study on the identification of appropriate visual cues for life-size displays, a perceptual-training experiment on decision-making in beach volleyball was conducted, contrasting two cueing interventions (functional vs. dysfunctional gaze path) with a conservative control condition (anticipation-related instructions). Gaze analyses revealed learning effects for the dysfunctional group only. Regarding decision-making, all groups showed enhanced performance with largest improvements for the control group followed by the functional and the dysfunctional group. Hence, the results confirm cueing effects on gaze behavior, but they also question its benefit for enhancing decision-making. However, before completely denying the method’s value, optimisations should be checked regarding, for instance, cueing-pattern characteristics and gaze-related feedback.