43 research outputs found
Thermal modeling of the TMT Telescope
Thermal modeling of the Thirty Meter Telescope (TMT) was conducted for evaluations of thermal performances by finite element (FE) and optical analysis tools. The thermal FE models consist of the telescope optical assembly systems, instruments, laser facility, control and electronic equipments, and telescope structural members. A three-consecutive-day thermal environment data was implemented for the thermal boundary created by Computational Fluid Dynamics (CFD) based on the environment conditions of the TMT site. Temporal and spatial temperature distributions of the optical assembly systems and the telescope structure were calculated under the environmental thermal conditions including air convections, conductions, heat flux loadings, and radiations. With the calculated temperature distributions, the thermo-elastic analysis was performed to predict thermal deformations of the telescope structure and the optical systems. The line of sight calculation was made using the thermally induced deformations of the optics and structures. Merit function routines (MFR) were utilized to calculate the Optical Path Difference (OPD) maps after repositioning the optics based on a best fit of M1 segment deformations. The goal of this thermal modeling is to integrate the mechanical and optical deformations in order to simulate the thermal effects with the TMT site environment data from CFD
Thermal performance prediction of the TMT optics
Thermal analysis for the Thirty Meter Telescope (TMT) optics (the primary mirror segment, the secondary mirror, and the tertiary mirror) was performed using finite element analysis in ANSYS and I-DEAS. In the thermal analysis, each of the optical assemblies (mirror, mirror supports, cell) was modeled for various thermal conditions including air convections, conductions, heat flux loadings, and radiations. The thermal time constant of each mirror was estimated and the temperature distributions of the mirror assemblies were calculated under the various thermal loading conditions. The thermo-elastic analysis was made to obtain the thermal deformation based on the resulting temperature distributions. The optical performance of the TMT optics was evaluated from the thermally induced mirror deformations. The goal of this thermal analysis is to establish thermal models by the FEA programs to simulate for an adequate thermal environment. These thermal models can be utilized for estimating the thermal responses of the TMT optics. In order to demonstrate the thermal responses, various sample time-dependent thermal loadings were modeled to synthesize the operational environment. Thermal responses of the optics were discussed and the optical consequences were evaluated
The relation between symmetry in food packaging and approach and avoidance words
Research on aesthetic science has demonstrated that people generally prefer symmetrical over asymmetrical compositions. However, it remains unclear whether and how such compositions relate to the concepts of approach and avoidance motivation, especially in consumer contexts. In addition, it is not known how symmetry may influence such concepts in contexts where objects can differ in terms of their hedonic values (symmetry/product taste congruency). In the present research, we evaluated the relation between visual symmetry of the packaging of products with different hedonic value (sweet, non-sweet, non-food) and approach and avoidance words. In two experiments, we found evidence that people associate symmetrical designs with approach words more often than asymmetrical designs. Importantly, however, we did not find evidence that such an effect is influenced by the hedonic value of the products. Our results have value for scholars and practitioners interested in the effect of aesthetic features of brand elements (such as a productâs packaging) on consumer motivation
Thermal modeling of the TMT Telescope
Thermal modeling of the Thirty Meter Telescope (TMT) was conducted for evaluations of thermal performances by finite element (FE) and optical analysis tools. The thermal FE models consist of the telescope optical assembly systems, instruments, laser facility, control and electronic equipments, and telescope structural members. A three-consecutive-day thermal environment data was implemented for the thermal boundary created by Computational Fluid Dynamics (CFD) based on the environment conditions of the TMT site. Temporal and spatial temperature distributions of the optical assembly systems and the telescope structure were calculated under the environmental thermal conditions including air convections, conductions, heat flux loadings, and radiations. With the calculated temperature distributions, the thermo-elastic analysis was performed to predict thermal deformations of the telescope structure and the optical systems. The line of sight calculation was made using the thermally induced deformations of the optics and structures. Merit function routines (MFR) were utilized to calculate the Optical Path Difference (OPD) maps after repositioning the optics based on a best fit of M1 segment deformations. The goal of this thermal modeling is to integrate the mechanical and optical deformations in order to simulate the thermal effects with the TMT site environment data from CFD
Thermal performance prediction of the TMT optics
Thermal analysis for the Thirty Meter Telescope (TMT) optics (the primary mirror segment, the secondary mirror, and the tertiary mirror) was performed using finite element analysis in ANSYS and I-DEAS. In the thermal analysis, each of the optical assemblies (mirror, mirror supports, cell) was modeled for various thermal conditions including air convections, conductions, heat flux loadings, and radiations. The thermal time constant of each mirror was estimated and the temperature distributions of the mirror assemblies were calculated under the various thermal loading conditions. The thermo-elastic analysis was made to obtain the thermal deformation based on the resulting temperature distributions. The optical performance of the TMT optics was evaluated from the thermally induced mirror deformations. The goal of this thermal analysis is to establish thermal models by the FEA programs to simulate for an adequate thermal environment. These thermal models can be utilized for estimating the thermal responses of the TMT optics. In order to demonstrate the thermal responses, various sample time-dependent thermal loadings were modeled to synthesize the operational environment. Thermal responses of the optics were discussed and the optical consequences were evaluated
Incommensurate and multiple- magnetic misfit order in the frustrated quantum spin ladder material antlerite, CuSO(OH)
In frustrated magnetic systems, the competition amongst interactions can
introduce extremely high degeneracy and prevent the system from readily
selecting a unique ground state. In such cases, the magnetic order is often
exquisitely sensitive to the balance among the interactions, allowing tuning
among novel magnetically ordered phases. In antlerite, CuSO(OH),
Cu () quantum spins populate three-leg zigzag ladders in a highly
frustrated quasi-one-dimensional structural motif. We demonstrate that at zero
applied field, in addition to its recently reported low-temperature phase of
coupled ferromagnetic and antiferromagnetic spin chains, this mineral hosts an
incommensurate helical+cycloidal state, an idle-spin state, and a multiple-
phase which is the magnetic analog of misfit crystal structures. The
antiferromagnetic order on the central leg is reentrant. The high tunability of
the magnetism in antlerite makes it a particularly promising platform for
pursuing exotic magnetic order.Comment: 18.3 pages, 16 Figures, follow-up paper to arXiv:2203.1534
Development of novel adenoviral vectors to overcome challenges observed with HAdV-5 based constructs
Recombinant vectors based on human adenovirus serotype 5 (HAdV-5) have been extensively studied in pre-clinical models and clinical trials over the last two decades. However, the thorough understanding of the HAdV-5 interaction with human subjects has uncovered major concerns about its product applicability. High vector-associated toxicity and widespread pre-existing immunity have been shown to significantly impede the effectiveness of HAdV-5 mediated gene transfer. It is therefore that the in depth knowledge attained working on HAdV-5 is currently being used to develop alternative vectors. Here, we provide a comprehensive overview of data obtained in recent years disqualifying the HAdV-5 vector for systemic gene delivery as well as novel strategies being pursued to overcome the limitations observed with particular emphasis on the ongoing vectorization efforts to obtain vectors based on alternative serotypes
A Multicenter Longitudinal MRI Study Assessing LeMan-PV Software Accuracy in the Detection of White Matter Lesions in Multiple Sclerosis Patients.
BACKGROUND
Detecting new and enlarged lesions in multiple sclerosis (MS) patients is needed to determine their disease activity. LeMan-PV is a software embedded in the scanner reconstruction system of one vendor, which automatically assesses new and enlarged white matter lesions (NELs) in the follow-up of MS patients; however, multicenter validation studies are lacking.
PURPOSE
To assess the accuracy of LeMan-PV for the longitudinal detection NEL white-matter MS lesions in a multicenter clinical setting.
STUDY TYPE
Retrospective, longitudinal.
SUBJECTS
A total of 206 patients with a definitive MS diagnosis and at least two follow-up MRI studies from five centers participating in the Swiss Multiple Sclerosis Cohort study. Mean age at first follow-up = 45.2âyears (range: 36.9-52.8âyears); 70 males.
FIELD STRENGTH/SEQUENCE
Fluid attenuated inversion recovery (FLAIR) and T1-weighted magnetization prepared rapid gradient echo (T1-MPRAGE) sequences at 1.5Â T and 3Â T.
ASSESSMENT
The study included 313 MRI pairs of datasets. Data were analyzed with LeMan-PV and compared with a manual "reference standard" provided by a neuroradiologist. A second rater (neurologist) performed the same analysis in a subset of MRI pairs to evaluate the rating-accuracy. The Sensitivity (Se), Specificity (Sp), Accuracy (Acc), F1-score, lesion-wise False-Positive-Rate (aFPR), and other measures were used to assess LeMan-PV performance for the detection of NEL at 1.5Â T and 3Â T. The performance was also evaluated in the subgroup of 123 MRI pairs at 3Â T.
STATISTICAL TESTS
Intraclass correlation coefficient (ICC) and Cohen's kappa (CK) were used to evaluate the agreement between readers.
RESULTS
The interreader agreement was high for detecting new lesions (ICC = 0.97, Pvalueâ<â10-20 , CK = 0.82, P value = 0) and good (ICC = 0.75, P valueâ<â10-12 , CK = 0.68, P value = 0) for detecting enlarged lesions. Across all centers, scanner field strengths (1.5 T, 3 T), and for NEL, LeMan-PV achieved: Acc = 61%, Se = 65%, Sp = 60%, F1-score = 0.44, aFPR = 1.31. When both follow-ups were acquired at 3 T, LeMan-PV accuracy was higher (Acc = 66%, Se = 66%, Sp = 66%, F1-score = 0.28, aFPR = 3.03).
DATA CONCLUSION
In this multicenter study using clinical data settings acquired at 1.5Â T and 3Â T, and variations in MRI protocols, LeMan-PV showed similar sensitivity in detecting NEL with respect to other recent 3Â T multicentric studies based on neural networks. While LeMan-PV performance is not optimal, its main advantage is that it provides automated clinical decision support integrated into the radiological-routine flow.
EVIDENCE LEVEL
4 TECHNICAL EFFICACY: Stage 2
The global abundance of tree palms
Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., â„10 cm diameter at breast height) abundance relative to coâoccurring nonâpalm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of longâterm climate stability. Lifeâform diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many nonâtree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of aboveâground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests
Development of novel adenoviral vectors to overcome challenges observed with HAdV-5-based constructs
Recombinant vectors based on human adenovirus serotype 5 (HAdV-5) have been extensively studied in pre-clinical models and clinical trials over the last two decades. However, the thorough understanding of the HAdV-5 interaction with human subjects has uncovered major concerns about its product applicability. High vector-associated toxicity and widespread pre-existing immunity have been shown to significantly impede the effectiveness of HAdV-5 mediated gene transfer. It is therefore that the in depth knowledge attained working on HAdV-5 is currently being used to develop alternative vectors. Here, we provide a comprehensive overview of data obtained in recent years disqualifying the HAdV-5 vector for systemic gene delivery as well as novel strategies being pursued to overcome the limitations observed with particular emphasis on the ongoing vectorization efforts to obtain vectors based on alternative serotypes