22 research outputs found
Genetic Analysis of two Evening Genes in the Arabidopsis thaliana Circadian Clock
No full textThe circadian clock generates biological rhythms that have an approximate period-length of 24 h. This endogenous timing mechanism is integrated in many signaling pathways and facilitates an optimal phase-relationship between internal and external rhythms. For example, the expression of photosynthesis genes is reflected in a rhythm that anticipates the environmental light-dark cycle. The circadian-clock system in plants has been investigated at the molecular level, and similar to other lineages, the plant clock has been found to consist of transcription/translation feedback loops. Currently, the circadian network is described to contain three interlocked feedback loops, and the CCA1/LHY-TOC1 loop is core within this feedback network. CCA1 and LHY are two MYB transcription factors that function in the morning and repress the expression of TOC1. Accordingly, TOC1 expression is delayed and peaks in the evening, and TOC1 function leads to subsequent induction of CCA1/LHY expression in the end of the night. How the rest of the components of the circadian system are connected to the property of the central oscillator remains unclear. In this thesis, two components of the circadian system, ELF4 and ELF3, were investigated. Both ELF4 and ELF3 are believed to function as inputs to the CCA1/LHY-TOC1 loop and their loss-of-function leads to arrhythmic behavior of the clock. ELF4 and ELF3 are unrelated in sequence, and both genes contain no evolutionarily conserved domains with known function. To this end, reverse-genetic approaches were applied in order to characterize the structure-function relationship of the ELF4- and ELF3-encoded products. In addition, the ELF4 and ELF3 circadian activities were related to each other, and both sequences were characterized phylogenetically. The comparison of members in the plant-specific ELF4 family revealed that two major subclades (ELF4 and EFL) are present in the phylogeny. The ELF4 consensus consists of a single domain, which is predicted to fold into a conserved alpha-helical structure. Accordingly, it was hypothesized that changes in this structure would correlate with ELF4 function. This was proven in two ways. First, ELF4-related sequences outside the ELF4 subclade were insufficient in complementation of the arrhythmic phenotype of the elf4 null mutant. Second, the effects of point mutations affecting ELF4 structural conservation correlate with the severity of the mutant phenotype. In addition, analysis of efl circadian phenotypes suggests roles for the EFL genes in fine-tuning of the circadian oscillator. The analysis of the elf4 point mutations concluded that ELF4 function is tightly connected to the light-induced expression of CCA1. This result confirmed previous findings for ELF4, and the relationship between ELF4 and the CCA1/LHY-TOC1 loop was further investigated by analyzing the effects of ELF4-overexpression on circadian parameters; this was compared to new studies on the elf4 loss-of-function mutation. It was found that there is a doseeffect of ELF4 on clock period, both at the molecular level and in plant physiological performance. Additionally, rhythmic expression of ELF4 is not required for sustained clock activity under constant conditions, and ELF4 has a critical role in clock entrainment to the light- Zeitgeber, possibly via a gating function. Epistatis analysis of ELF4 and ELF3 defined ELF3 as the most upstream regulator of light input to the central oscillator. ELF3 function was further analyzed by characterization of a newly found allele termed elf3-G12. This mutant was found to display subtle and clock-specific phenotypes. Expression analyses revealed that ELF3 misexpression confers phase shift of central clock genes and ELF3 is likely to be most associated with TOC1 function under free-running conditions. Furthermore, it was determined that the phenotype of the elf3-G12 mutant is related to PHYB-interaction, supporting the position of ELF3 at the convergence point of light transduction and input to the circadian clock
Effect of Multispectral Pulsed Light-Emitting Diodes on the Growth, Photosynthetic and Antioxidant Response of Baby Leaf Lettuce (Lactuca sativa L.)
No full textThe effect of multicolor pulsed light-emitting diode (LED) irradiation on lettuce “Defender” growth, photosynthetic performance and antioxidant properties was studied. The experiments were designed to compare the continuous and pulsed lighting (0.5, 1 kHz; 50% duty ratio) effects of B450, G520, R660 and FR735 lighting components, maintaining total diurnal integral light quantity (DLI 14.4 mol m−2 day−1) constant during the 16-h photoperiod. The results showed that lettuce grown under pulsed irradiation displayed superior growth performance, including a significant enhancement of fresh (~32%) and dry biomass (~36%) and leaf area (~48%). Lettuce cultivated in both pulsed light treatments was characterized by the higher photosynthetic rate, chlorophyll (a,b) and carotenoid concentration. However, the total phenol and antioxidant properties in lettuce were more dependent on the specific pulsed light frequency. Only treatment with 1 kHz frequency was effective for higher phenol content, 2,20-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging activity and Fe2+ reducing antioxidant power (FRAP). Thus, our results propose the role of pulsed LED light in improving the photosynthetic efficiency and antioxidative properties of lettuce plants cultivated indoors. In the future, pulsed lighting techniques should be included in the development of artificial lighting systems in controlled environment agriculture (CEA) to produce high-quality crops with the possibility to save electricity
Collaborative Learning Online: A Case Study
No full textThe paper reports on findings from the use of a VLE-pilot designed from a perspective of collaborative learning. More specifically, it scrutinizes what ways this environment proves to be supportive for collaboration and interaction amongst theology learners distributed in time and space. Moreover, the author question if the result can be ascribed the VLE design or rather the collaborative instruction process that was enhanced and supported by the teacher. Finally, the author touches upon which features are significant for design and delivery of CSCL
Structural insights into the function of the core-circadian factor TIMING OF CAB2 EXPRESSION 1 (TOC1)
No full textAbstract Background The plant circadian clock has at its core a feedback loop that includes TIMING OF CAB2 EXPRESSION 1 (TOC1). This protein has an as of yet unknown biochemical activity. It has been noted that the extreme amino-terminus of this protein is distantly related in sequence to response regulators (RR), and thus TOC1 is a member of the so-called pseudo response regulator (PRR) family. As well, the extreme carboxy-terminus has a small sequence stretch related to the other PRRs and CONSTANS (CO)-like proteins, and this peptide stretch has been termed the CCT (for CONSTANS, CONSTANS-LIKE, TOC1) domain. Methods To extend further our understanding of the TOC1 protein, we performed a ROSETTA structural prediction on TOC1 orthologues from four plant species. Phylogenetic interpretations assisted in model construction. Results From our models, we suggest that TOC1 is a three-domain protein: TOC1 has an amino-terminal signaling-domain related to response receivers, a carboxy-terminal domain that could participate both in metal binding and in transcriptional regulation, and a linker domain that connects the two. Conclusion The models we present should prove useful in future hypothesis-driven biochemical analyses to test the predictions that TOC1 is a multi-domain signaling component of the plant circadian clock.</p
Trust and IT security in IT outsourcing
No full textTrust between the vendor and client has been identified as a critical success factor in IT outsourcing, and thus, building a trusting relationship is often strived for. However, academics request more research on the effect of different trust building mechanisms. Moreover, IT security has received increasing attention in IT outsourcing, and practitioners question how IT security can affect the level of trust between the parties. Still, empirical research on the connection between IT security and trust has not been conducted before. Hence, this study aims to contribute to the research by addressing two questions. First, how do practitioners from the Norwegian IT outsourcing market experience and explain the effect of trust building mechanisms implemented between client and vendor. Second, how do practitioners argue that IT security can affect trust between vendor and client.
This paper is a continuation of the author s pre-diploma thesis which, based on a literature review, put forward the model of trust building in IT outsourcing (Austad and Lossius, 2014). The first research question of this paper aims to support and/or revise this model. Moreover, the pre-diploma thesis further proposed that IT security could be argued to affect trust. The second research question aims to empirically evaluate this proposition.
A multiple case study investigation of ten Norwegian IT outsourcing relationships through 18 semi-structured interviews forms the basis for analysis and discussion. The findings from each case was analyzed separately to look for arguments supporting or contradicting the model of trust building in IT outsourcing, and the proposed link between IT security and trust. Then, the arguments and explanations were combined in a cross case analysis, which represents the primary focus of the paper. The cross case analysis entailed looking for patterns in supporting or contradictory arguments, which were further linked and compared with the theory in the conceptual background.
Overall, this study reveals multiple contributions to theory and practitioners. Firstly, it provides academics and practitioners with a revised model of trust building in IT outsourcing. A majority of the mechanisms and dynamics in the original model were supported by the findings, thus strengthening the trust building effects suggested by extant literature upon which the model was built. Furthermore, this study resulted in certain revisions to the model. These comprise of adding investments as a trust building mechanism, and adding delivery and removing control as trust building dynamics. All the types of trust in the model were found to be supported. Also, the findings suggest that how the mechanisms are implemented is of great importance for its resulting effect on trust. As such, the dynamics provides explanations of how the mechanisms should be implemented to build trust. Overall, the revised model represents an empirically supported and improved explanation of trust building in IT outsourcing. Secondly, an emergent finding of the study was the model of the dynamics role in trust building in IT outsourcing. The model illustrates how delivery builds a foundation of trust, based on receiving expected gains and meeting expectations of abilities. However, to build higher levels of trust, other dynamics must be facilitated. Lastly, this study is the first, to the authors knowledge, to establish a connection between IT security and trust based on an empirical investigation. Specifically, it suggest that the extent to which IT security can affect trust, depends upon the perceived importance of this component, relative to other parts of the delivery
Applying sensory modulation to mental health inpatient care to reduce seclusion and restraint: a case control study
No full textBACKGROUND: Clinical training in managing conflicts and preventing violence seldom contains sensory modulation (SM) as a method to de-escalate and prevent restraint and seclusion. Sensory-based interventions promote adaptive regulation of arousal and emotion. SM is a complementary approach that is associated with reduced rates of seclusion and restraint in mental healthcare, but there is need for more research in this area.AIMS: Using SM to reduce restraint and seclusion in inpatient mental health care.METHODS: The study included two similar psychiatric units where one unit implemented SM and one unit served as the control group. In the very beginning of the study, a staff-training program in the use of SM including assessment tools and intervention strategies was established. Data on restraint and forced medicine were sampled post the course of the year of implementation and compared with the control group.RESULTS: The use of belts decreased with 38% compared to the control group. The use of forced medication decreased with 46% compared to the control group. Altogether the use of physical restraint and forced medication decreased significantly with 42% (p < .05).CONCLUSIONS: Implementing a SM approach in mental healthcare facilities has a significant effect on the reduction of restraint and seclusion. As a part of the implementation, staff training and education in SM are crucial.</p
Structural insights into the function of the core-circadian factor TIMING OF CAB2 EXPRESSION 1 (TOC1)
No full textTrust and IT security in IT outsourcing
No full textTrust between the vendor and client has been identified as a critical success factor in IT outsourcing, and thus, building a trusting relationship is often strived for. However, academics request more research on the effect of different trust building mechanisms. Moreover, IT security has received increasing attention in IT outsourcing, and practitioners question how IT security can affect the level of trust between the parties. Still, empirical research on the connection between IT security and trust has not been conducted before. Hence, this study aims to contribute to the research by addressing two questions. First, how do practitioners from the Norwegian IT outsourcing market experience and explain the effect of trust building mechanisms implemented between client and vendor. Second, how do practitioners argue that IT security can affect trust between vendor and client.
This paper is a continuation of the author s pre-diploma thesis which, based on a literature review, put forward the model of trust building in IT outsourcing (Austad and Lossius, 2014). The first research question of this paper aims to support and/or revise this model. Moreover, the pre-diploma thesis further proposed that IT security could be argued to affect trust. The second research question aims to empirically evaluate this proposition.
A multiple case study investigation of ten Norwegian IT outsourcing relationships through 18 semi-structured interviews forms the basis for analysis and discussion. The findings from each case was analyzed separately to look for arguments supporting or contradicting the model of trust building in IT outsourcing, and the proposed link between IT security and trust. Then, the arguments and explanations were combined in a cross case analysis, which represents the primary focus of the paper. The cross case analysis entailed looking for patterns in supporting or contradictory arguments, which were further linked and compared with the theory in the conceptual background.
Overall, this study reveals multiple contributions to theory and practitioners. Firstly, it provides academics and practitioners with a revised model of trust building in IT outsourcing. A majority of the mechanisms and dynamics in the original model were supported by the findings, thus strengthening the trust building effects suggested by extant literature upon which the model was built. Furthermore, this study resulted in certain revisions to the model. These comprise of adding investments as a trust building mechanism, and adding delivery and removing control as trust building dynamics. All the types of trust in the model were found to be supported. Also, the findings suggest that how the mechanisms are implemented is of great importance for its resulting effect on trust. As such, the dynamics provides explanations of how the mechanisms should be implemented to build trust. Overall, the revised model represents an empirically supported and improved explanation of trust building in IT outsourcing. Secondly, an emergent finding of the study was the model of the dynamics role in trust building in IT outsourcing. The model illustrates how delivery builds a foundation of trust, based on receiving expected gains and meeting expectations of abilities. However, to build higher levels of trust, other dynamics must be facilitated. Lastly, this study is the first, to the authors knowledge, to establish a connection between IT security and trust based on an empirical investigation. Specifically, it suggest that the extent to which IT security can affect trust, depends upon the perceived importance of this component, relative to other parts of the delivery
