13 research outputs found
Motivated to Share? Using the PersonāEnvironment Fit Theory to Explain the Link between Public Service Motivation and Knowledge Sharing
Despite the growing evidence that public service motivation (PSM) is an important source of employee outcomes, there is still a dearth of empirical evidence on whether it stirs oneās willingness to share learned knowledge with other members of an organization. The authors explore the mediating role of workersā perceived fit in a given setting as a causal mechanism through which PSM promotes knowledge-sharing indirectly. Findings based on the primary data of 1048 occupationally diverse employees working in 33 local governments in South Korea show that PSM has a positive impact on knowledge sharing, personāgroup (PāG) fit, and personājob (PāJ) fit, and PāG fit and PāJ fit plays a mediating role in improving knowledge sharing, respectively, while personāsupervisor (PāS) fit does not. This study interprets these results as suggesting that PāS it should be considered independently from environmental factors in the public organization, as it is derived from the interrelationship between employees and supervisors that began in the hierarchy of the organization, and thus is difficult to be related to other factors. Based on literature review and empirical analysis, this study presents theoretical and policy implications
Probing protein structural requirements for activation of membrane-bound NAC transcription factors in Arabidopsis and rice
Many transcription factors are stored in a dormant state through association with the cellular membranes in plants Upon stimulation by internal and environmental signals, they are activated through proteolytic cleavage events either by membrane-associated proteases or by ubiquitination-dependent proteasome activities Controlled proteolytic activation of the dormant, membrane-bound transcription factors (MTFs) is an intriguing way of ensuring rapid transcriptional responses to abrupt environmental changes However, the underlying activation mechanisms and protein structural requirements are largely unknown in most cases Here, we analyzed the primary and secondary structures of the NAC MTFs, particularly of the amino acid sequences surrounding the putative cleavage sites Interestingly, the putative biologically active forms have strong hydrophilic motifs at their C-termini. Accordingly, transgenic Arabidopsis plants overexpressing the truncated forms having the C-terminal hydrophilic motifs exhibited distinct phenotypes. The finding was also applicable to rice NAC MTFs Among the full-size OsNTL2 protein and a series of truncated OsNTL2 forms lacking the C-terminal transmembrane motif, only the OsNTL2 form (Os2 Delta C4) having a strong hydrophilic peak at the C-terminus exhibited a high tianscriptional activation activity when assayed in yeast cells Our findings will provide insights into how plant MTFs are activated to release the biologically active forms (C) 2010 Elsevier Ireland Ltd All rights reserved
Long-Range Transport of SO2 from Continental Asia to Northeast Asia and the Northwest Pacific Ocean: Flow Rate Estimation Using OMI Data, Surface in Situ Data, and the HYSPLIT Model
This present study suggests a method to calculate the SO2 flow rate from a source area to receptor areas on a regional scale using Ozone Monitoring Instrument (OMI) SO2 products, surface in situ SO2 data, and the hybrid single particle Lagrangian integrated trajectory (HYSPLIT) model. The method was implemented to calculate the SO2 flow rate from continental Asia to northeast Asia and the Northwest Pacific Ocean. For the high SO2 events when SO2 was transported from continental Asia to Japan via the Korean Peninsula on 22ā24 December 2006, the long-range transported SO2 flow rates were 14.0 (21.0) MgĀ·hā1 OMIĀ·girdā1 at Gangneung (Seoul) in Korea and 4.2 (5.3) MgĀ·hā1 OMIĀ·girdā1 at Hiroshima (Kumamoto) in Japan. For the long-range transport of SO2 from continental Asia to the Northwest Pacific Ocean on 6ā7 October 2008 (9ā11 October 2006), the flow rates were 16.1 (16.2) MgĀ·hā1 OMIĀ·girdā1 at Hokkaido, Japan (Vladivostok, Russia) and 5.6 (16.7)Ā MgĀ·hā1 OMIĀ·girdā1 at the Aleutian Islands, Northwest Pacific Ocean (Bering Sea). The mean rates of decrease in the SO2 flow rate per 1000 km were also calculated between continental Asia and the receptor areas. Uncertainties in the flow rate estimates were also assessed and discussed
Modulation of sugar metabolism by an INDETERMINATE DOMAIN transcription factor contributes to photoperiodic flowering in Arabidopsis
P>There has been a long-standing interest in the role played by sugars in flowering. Of particular interest is how sugar-related signals are integrated into flowering genetic pathways. Here, we demonstrate that the INDETERMINATE DOMAIN transcription factor AtIDD8 regulates photoperiodic flowering by modulating sugar transport and metabolism. We found that whereas AtIDD8-deficient idd8 mutants exhibit delayed flowering under long days, AtIDD8-overexpressing plants (35S:IDD8) show early flowering. In addition, the sucrose synthase genes SUS1 and SUS4 were upregulated in 35S:IDD8 plants but downregulated in idd8 mutants, in which endogenous sugar levels were altered. AtIDD8 activates the SUS4 gene by binding directly to its promoter, resulting in promoted flowering in SUS4-overexpressing plants. SUS4 expression also responds to photoperiodic signals. Notably, the AtIDD8 gene is suppressed by sugar deprivation. Therefore, we conclude that AtIDD8 regulation of sugar transport and metabolism is linked to photoperiodic flowering
Investigation of Simultaneous Effects of Aerosol Properties and Aerosol Peak Height on the Air Mass Factors for Space-Borne NO2 Retrievals
We investigate the simultaneous effects of aerosol peak height (APH), aerosol properties, measurement geometry, and other factors on the air mass factor for NO2 retrieval at sites with high NO2 concentration. A comparison of the effects of high and low surface reflectance reveals that NO2 air mass factor (AMF) values over a snowy surface (surface reflectance 0.8) are generally higher than those over a deciduous forest surface (surface reflectance 0.05). Under high aerosol optical depth (AOD) conditions, the aerosol shielding effect over a high-albedo surface is revealed to reduce the path-length of light at the surface, whereas high single scattering albedo (SSA) conditions (e.g., SSA = 0.95) lead to an increase in the aerosol albedo effect, which results in an increased AMF over areas with low surface reflectance. We also conducted an in-depth study of the APH effect on AMF. For an AOD of 0.1 and half width (HW) of 5 km, NO2 AMF decreases by 29% from 1.36 to 0.96 as APH changes from 0 to 2 km. In the case of high-AOD conditions (0.9) and HW of 5 km, the NO2 AMF decreases by 240% from 1.85 to 0.54 as APH changes from 0 to 2 km. The AMF variation due to error in the model input parameters (e.g., AOD, SSA, aerosol shape, and APH) is also examined. When APH is 0 km with an AOD of 0.4, SSA of 0.88, and surface reflectance of 0.05, a 30% error in AOD induces an AMF error of between 4.85% and ā3.67%, an SSA error of 0.04 leads to NO2 VCD errors of between 4.46% and ā4.77%, and a 30% error in AOD induces an AMF error of between ā9.53% and 8.35% with an APH of 3 km. In addition to AOD and SSA, APH is an important factor in calculating AMF, due to the 2 km error in APH under high-SZA conditions, which leads to an NO2 VCD error of over 60%. Aerosol shape is also found to have a measureable effect on AMF under high-AOD and small relative azimuth angle (RAA) conditions. The diurnal effect of the NO2 profile is also examined and discussed
Investigation of Simultaneous Effects of Aerosol Properties and Aerosol Peak Height on the Air Mass Factors for Space-Borne NO2 Retrievals
We investigate the simultaneous effects of aerosol peak height (APH), aerosol properties, measurement geometry, and other factors on the air mass factor for NO2 retrieval at sites with high NO2 concentration. A comparison of the effects of high and low surface reflectance reveals that NO2 air mass factor (AMF) values over a snowy surface (surface reflectance 0.8) are generally higher than those over a deciduous forest surface (surface reflectance 0.05). Under high aerosol optical depth (AOD) conditions, the aerosol shielding effect over a high-albedo surface is revealed to reduce the path-length of light at the surface, whereas high single scattering albedo (SSA) conditions (e.g., SSA = 0.95) lead to an increase in the aerosol albedo effect, which results in an increased AMF over areas with low surface reflectance. We also conducted an in-depth study of the APH effect on AMF. For an AOD of 0.1 and half width (HW) of 5 km, NO2 AMF decreases by 29% from 1.36 to 0.96 as APH changes from 0 to 2 km. In the case of high-AOD conditions (0.9) and HW of 5 km, the NO2 AMF decreases by 240% from 1.85 to 0.54 as APH changes from 0 to 2 km. The AMF variation due to error in the model input parameters (e.g., AOD, SSA, aerosol shape, and APH) is also examined. When APH is 0 km with an AOD of 0.4, SSA of 0.88, and surface reflectance of 0.05, a 30% error in AOD induces an AMF error of between 4.85% and ā3.67%, an SSA error of 0.04 leads to NO2 VCD errors of between 4.46% and ā4.77%, and a 30% error in AOD induces an AMF error of between ā9.53% and 8.35% with an APH of 3 km. In addition to AOD and SSA, APH is an important factor in calculating AMF, due to the 2 km error in APH under high-SZA conditions, which leads to an NO2 VCD error of over 60%. Aerosol shape is also found to have a measureable effect on AMF under high-AOD and small relative azimuth angle (RAA) conditions. The diurnal effect of the NO2 profile is also examined and discussed
Investigations of the Diurnal Variation of Vertical HCHO Profiles Based on MAX-DOAS Measurements in Beijing: Comparisons with OMI Vertical Column Data
An investigation into the diurnal characteristics of vertical formaldehyde (HCHO) profiles was conducted based on multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements in Beijing during the CAREBEIJING campaign, covering a month-long period through August and September 2006. Vertical HCHO profiles were retrieved based on a combined differential optical absorption spectroscopy (DOAS) technique and an optimal estimation method (OEM). The HCHO volume-mixing ratio (VMR) was found to be highest in the layer from the surface up to an altitude of 1 km and to decrease with altitude above this layer. In all retrieved profiles, HCHO was not detected in the layer from 3ā4 km. Over the diurnal cycle, the HCHO VMR values were generally highest at 15:00 local time (LT) and were lower in the morning and late afternoon. The mean HCHO VMRs were 6.17, 1.82, and 0.80 ppbv for the 0ā1, 1ā2, and 2ā3-km layers, respectively, at 15:00 LT, whereas they were 3.54 (4.79), 1.06 (1.43), and 0.46 (0.63) ppbv for the 0ā1, 1ā2, and 2ā3-km layers, respectively, at 09:00 (17:00) LT. The HCHO VMRs reached their highest values at 15:00 LT on August 19, which were 17.71, 5.20, and 2.31 ppbv for the 0ā1, 1ā2, and 2ā3-km layers, respectively. This diurnal pattern implies that the photo-oxidation of volatile organic compounds (VOCs) was most active at 15:00 LT for several days during the campaign period. In a comparison of the derived HCHO VCDs with those obtained from the Ozone Monitoring Instrument (OMI) measurements, the HCHO vertical column density (VCD) values obtained from the OMI measurements tend to be smaller than those from the MAX-DOAS
An equal-TE ultrafast 3D gradient-echo imaging method with high tolerance to magnetic susceptibility artifacts: Application to BOLD functional MRI
To develop an ultrafast 3D gradient echoābased MRI method with constant TE and high tolerance to B0 inhomogeneity, dubbed ERASE (equal-TE rapid acquisition with sequential excitation), and to introduce its use in BOLD functional MRI (fMRI). Theory and Methods: Essential features of ERASE, including spin behavior, were characterized, and a comparison study was conducted with conventional EPI. To demonstrate high tolerance to B0 inhomogeneity, in vivo imaging of the mouse brain with a fiber-optic implant was performed at 9.4 T, and human brain imaging (including the orbitofrontal cortex) was performed at 3 T and 7 T. To evaluate the performance of ERASE in BOLD-fMRI, the characteristics of SNR and temporal SNR were analyzed for in vivo rat brains at 9.4 T in comparison with multislice gradient-echo EPI. Percent signal changes and t-scores are also presented. Results: For both mouse brain and human brain imaging, ERASE exhibited a high tolerance to magnetic susceptibility artifacts, showing much lower distortion and signal dropout, especially in the regions involving large magnetic susceptibility effects. For BOLD-fMRI, ERASE provided higher temporal SNR and t-scores than EPI, but exhibited similar percent signal changes inin vivo rat brains at 9.4 T. Conclusion: When compared with conventional EPI, ERASE is much less sensitive, not only to EPI-related artifacts such as Nyquist ghosting, but also to B0 inhomogeneity including magnetic susceptibility effects. It is promising for use in BOLD-fMRI, providing higher temporal SNR and t-scores with constant TE when compared with EPI, although further optimization is needed for human fMRI.11Nsciescopu