Using Social Network Analysis to Measure Student Collaboration in an Undergraduate Capstone Course

Social network analysis offers a unique way for instructors to visualize collaboration and communication within a course and see relationships between individu¬als, groups, teams, or cliques. We used social network analysis to measure the growth of collaboration in the capstone AGEDS 450 Farm Management and Oper¬ation course at Iowa State University. With the strate-gic implementation of collaboratively intense assign¬ments, student collaboration grew from the midpoint of the semester to the end of the semester. Overall density of the network increased from 0.25 at the midpoint to 0.35 at the end of the semester (40% growth). Each stu¬dent’s number of communication ties increased over the course of the semester to 17.2. Average geodesic dis¬tance between nodes decreased 11.7% from the mid¬point to the end of the semester, resulting in an average pathway length of 1.66 to connect any two students; this improved communication efficiency in the course. No cutpoint existed at the midpoint or the end of semester, showing no risk of collapse in the network. The overall network became more complex, indicating a more inclu¬sive collaborative environment. We recommend that instructors include structured activities that emphasize student collaboration to help develop strong information networks in other courses

Fire resistance performance of submerged floating tunnel under various fire conditions

Submerged Floating Tunnels (SFT) were researched by countries had many island as Norway, Italy,\ud China, and Japan. Several sites were examined in China and Norway. Most of them investigated about seismic, dynamic,\ud and collision performance. However, present researches lack to apply the construction fields, therefore, additional\ud researches need. Fire resistance performance of the SFT is important one of the various researches. If fire break out in\ud SFT, it is damaged by thermal loads. The damage of the SFT varies by type of fire. Structure of the SFT is able to\ud collapse partially by fire scale and fire exposure time. For this reason, fire resistance design of the SFT must be\ud suggested. Fire resistance performance of SFT could be investigating for fire resistance design of SFT. Fire condition\ud could be expressed fire curves which are suggested by fire scale and fire exposure time. In this paper, temperature\ud distributions of the SFT were investigated through FE analysis under various fire conditions. Heat transfer analysis was\ud applied to investigate conduction of heat by fire. And there was to draw the biggest influence fire condition to the SFT\ud from FE analysis results. Also, preliminary study was performed for fire resistance design

Use of genetic markers in Alstroemeria

This thesis describes the results of various applications of the AFLP technique in Alstroemeria . The aim of this study was 1) to adapt the AFLP technique for Alstroemeria species which has a large genome size, 2) to study the genetic diversity of Alstroemeria species of Chilean and Brazilian origin, 3) to construct genetic linkage maps of the A. aurea genome and 4) to map in A. aurea QTLs involved in ornamentally important traits.The AFLP technique was adapted to obtain a method that produces clear fingerprints in Alstroemeria . We used PCR primers with two selective nucleotides (= Eco RI+2/ Mse I+2) during preamplification before PCR amplification with 33P labelled primers with four selective nucleotides (Eco RI+4/ Mse I+4) in the final step (Chapter 2). It was noticed that increasing the number of intermediate pre-amplifications was not preferable, because of the increased bias due to competition between fragments and the extra labour. The GC contents of the selective nucleotides had a significant influence on the number of bands. The primer combinations with CG residues in the selective nucleotides showed fewer bands per lane (Chapter 2). This result confirmed earlier other observations that the Alstroemeria genome is AT rich.In our study, the reproducibility of the AFLP technique for genetic analysis was verified. All bands in the fingerprints of offspring genotypes could be explained from the parental genotypes (Chapter 2). No PCR artefacts, mismatching and random priming had been detected in general, but reliable fingerprints of a species with a large genome such as Alstroemeria can be obtained with Eco RI+2/ Mse I+2 preamplification and Eco RI+4/ Mse I+4 for final amplification.AFLP fingerprints were produced of 22 Alstroemeria species, one interspecific hybrid ( A. aurea x A. inodora ) and the distantly related species Bomarea salsilla and Leontochir ovallei as outgroup (Chapter 3). AFLP template of three accessions per species was mixed to obtain a more generalised fingerprint to represent an Alstroemeria species. Three primer combinations (E+ACCA/M+CATG, E+ACCT/M+CATC and E+AGCC/M+CACC), selected on the basis of their fingerprint quality, resulted into a data set of 272, 211 and 233 markers per primer combination.The UPGMA dendrogram revealed three main clusters: the Chilean species, the Brazilian species and the outgroup. The principal co-ordinate plot revealed the same three groups, but additionally, the A. ligtu group was separated from the Chilean group. A. aurea was positioned between Chilean and Brazilian groups. The unique position of A. aurea suggests that other Chilean and Brazilian species may have evolved from A. aurea ecotypes (Tombolato, A.F.C., pers. comm.). A. haemantha Ruiz and Pavon was grouped with A. ligtu subsp. ligtu , A. ligtu subsp. incarnata and A. ligtu subsp. simsii . This confirms previous studies which assigned A. haemantha to the A. ligtu group. In the monography of Bayer on taxonomy of Chilean species suggested that A. haemantha and A. ligtu were synonymous names. Two species, A. umbellata and A. pelegrina , showed a genetic distance of only 0.26 GD, which is in the range of within-species genetic distances. The interspecific hybrid ( A. aurea´A. inodora ) showed a genetic distance of 0.45 GD and 0.59 GD with A. inodora and A. aurea , respectively. In the matrix of pairwise genetic distances these values were the lowest observed between the hybrid and any of the putative parental species. This example demonstrates that it seems to be feasible to identify the parental species of an interspecific hybrid on the basis of genetic distance values. An F 1 hybrid mapping population (N = 134) was established between two diploid A. aurea genotypes (A002 x A003; 2n = 2x = 16) in order to construct linkage maps. Over 374 polymorphic AFLP markers have been produced with 28 primer combinations (Chapter 4). Around 70 % of these polymorphic markers have been assigned to the linkage maps in either of the A002 and A003 parental map. As a result, these maps consisted of 8 and 10 linkage groups with 122 and 214 markers covering 306.3 and 605.6 cM, respectively. These differences between the two maps in terms of number of markers and total map length, indicates a different level of heterozygosity. This could have been caused by self-pollination for sexual maintenance of the accession by the breeders, leading to fixation on 50% of the genome. The two maps were integrated by using the F 2 type of AFLP markers. The pollen colour locus was assigned on the A002-6 linkage group.We also tested another method to handle the complexity of the large genome. Instead of adding selective nucleotides to 6-cutter template we generated AFLP template with an 8-cutter restriction enzyme Sse 8387I. Fingerprints generated with Eco RI+4/ Mse I+4 primers produced around 80 clear bands from which around 16 markers were polymorphic, whereas the fingerprints generated with Sse +2/ Mse I+3 primers produced 30 clear bands from which 9 markers were polymorphic (Chapter 4). On the one hand the simpler Sse 8387I / Mse I fingerprints were more easy to evaluate, on the other hand a higher number of useful markers could be obtained with the Eco RI/ Mse I fingerprints.The previously established A. aurea linkage maps were used in order to map and characterise QTL for important traits, such as leaf morphology, the colour, size and shape of the flower, tepal stripe width, and productivity in terms of number of flowering stems and flowering period (Chapter 5). The majority of these traits were chosen on the basis of the UPOV list of cultivar descriptors. For all traits, except for flower openness, the offspring trait values displayed a continuous distribution, not deviating from normality. The transgressive segregations that phenotypic values of the progeny go beyond the parental values have been observed for the morphological traits of the leaves due to heterozygosity in the parents. Interval mapping and the Kruskal-Wallis test was performed to detect and to localize QTL, using separate parental data sets and non-integrated maps of A002 and A003. For interval mapping, a permutation test was used to empirically determine the significance threshold of the LOD score for each linkage group. This resulted in putative QTL with 95 % confidence threshold values ranging between LOD = 2.6 and LOD = 4.9, or in QTL with 99% confidence threshold values ranging between LOD = 3.85 and LOD = 4.81. In total 22 QTL for the traits studied were located throughout the map. The phenotypic variance explained by the QTL ranged from 11.2% to 32.2%. It was observed that many of the QTL did not reach high LOD values, or did not reach highly significant K-values in the Kruskal-Wallis test. It was also observed that QTL detected by interval mapping were not often confirmed by the Kruskal-Wallis test and vice versa. Probable explanations were discussed in Chapter 5. The overall conclusion is that, despite its large genome, the AFLP technology can be applied relatively easily in Alstroemeria for genetic and biodiversity studies.</p

Bending strength analysis of steel-composite submerged floating tunnels

A submerged floating tunnel (SFT) must have enough strength to resist to various external loadings such\ud as bending, torsion, tension, and compression. The expected main deformation of SFT is caused by bending moment.\ud And this bending moment makes tensile stress and compression stress on the wall of SFT. Thus, bending moment is a\ud main affecting factor on the safety of SFT. Until now, a reinforced concrete tunnel was suggested for SFT by other\ud researchers. In this study, an internally confined hollow reinforced concrete tunnel and a double skinned composite\ud tubular tunnel were proposed. And their bending strengths were studied and compared with that of a reinforced concrete\ud tunnel. The analysis results showed the proposed SFT structures had enough strength to guarantee safety

Magneto-optical investigations of Ag-sheathed Bi-2223 tapes with ferromagnetic shielding

An increase in the critical current and suppression of AC losses in superconducting wires and tapes with soft magnetic sheath have been predicted theoretically and confirmed experimentally. In this work we present the results of magneto-optical investigations on a series of Ag-sheathed Bi-2223 tapes with Ni coating. We visualize distributions of magnetic field at increasing external field and different temperatures, demonstrating a difference between the flux propagation in the superconductor with Ni rims and a reference sample without Ni coating.Comment: 2 page

Submergence of the Sidebands in the Photon-assisted Tunneling through a Quantum Dot Weakly Coupled to Luttinger Liquid Leads

We study theoretically the photon-assisted tunneling through a quantum dot weakly coupled to Luttinger liquids (LL) leads, and find that the zero bias dc conductance is strongly affected by the interactions in the LL leads. In comparison with the system with Fermi liquid (FL) leads, the sideband peaks of the dc conductance become blurring for 1/2<g<1, and finally merge into the central peak for g<1/2, (g is the interaction parameter in the LL leads). The sidebands are suppressed for LL leads with Coulomb interactions strong enough, and the conductance always appears as a single peak for any strength and frequency of the external time-dependent field. Furthermore, the quenching effect of the central peak for the FL case does not exist for g<1/2.Comment: 9 pages, 4 figure

Nonlinear Optical Properties Of GeSbS Chalcogenide Waveguides

We characterize the nonlinear optical properties of GeSbS chalcogenide glasses with fiber-based experiments. A waveguide nonlinear parameter of 7 W-1/m and nonlinear refractive index of 3.71 x 10-18 m2/W are estimated by self-phase modulation. A GeSbS waveguide could also generate a supercontinuum from 1280 to 2120 nm at the -30 dB level for maximum coupled power of 340 W, showing a 14-fold spectral broadening of the input spectrum explained by cascaded stimulated Raman scattering

Enhanced Superconductivity in Sr2CuO4-v

A critical review of previous investigations of the superconductivity with enhanced Tc ~ 95K found in Sr2CuO4-v shows that new physics occurs in a highly overdoped region of the cuprate phase diagram. Moreover, evidence is adduced from the literature that 30% of the oxygen sites in the CuO2 layers are vacant, a conclusion which is at odds with the universally made assumption that superconductivity originates in stoichiometric CuO2 layers. While further research is needed in order to identify the pairing mechanism(s) responsible for the enhanced Tc, we suggest possible candidates

Bulk-sensitive photoemission spectroscopy of A_2FeMoO_6 double perovskites (A=Sr, Ba)

Electronic structures of Sr_2FeMoO_6 (SFMO) and Ba_2FeMoO_6 (BFMO) double perovskites have been investigated using the Fe 2p->3d resonant photoemission spectroscopy (PES) and the Cooper minimum in the Mo 4d photoionization cross section. The states close to the Fermi level are found to have strongly mixed Mo-Fe t_{2g} character, suggesting that the Fe valence is far from pure 3+. The Fe 2p_{3/2} XAS spectra indicate the mixed-valent Fe^{3+}-Fe^{2+} configurations, and the larger Fe^{2+} component for BFMO than for SFMO, suggesting a kind of double exchange interaction. The valence-band PES spectra reveal good agreement with the LSDA+U calculation.Comment: 4 pages, 3 figure

Detection of Quantitative Trait Loci Affecting Fat Deposition Traits in Pigs

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License http://creativecommons.org/licenses/by-nc/3.0/ which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original work is properly cited.Quantitative trait loci (QTL) associated with fat deposition traits in pigs are important gene positions in a chromosome that influence meat quality of pork. For QTL study, a three generation resource population was constructed from a cross between Korean native boars and Landrace sows. A total of 240 F2 animals from intercross of F1 were produced. 80 microsatellite markers covering chromosomes 1 to 10 were selected to genotype the resource population. Intervals between adjacent markers were approximately 19 cM. Linkage analysis was performed using CRIMAP software version 2.4 with a FIXED option to obtain the map distances. For QTL analysis, the public web-based software, QTL express (http://www.qtl.cap.ed.ac.uk) was used. Two significant and two suggestive QTL were identified on SSC 6, 7, and 8 as affecting body fat and IMF traits. For QTL affecting IMF, the most significant association was detected between marker sw71 and sw1881 on SSC 6, and a suggestive QTL was identified between sw268 and sw205 on SSC8. These QTL accounted for 26.58% and 12.31% of the phenotypic variance, respectively. A significant QTL affecting IMF was detected at position 105 cM between markers sw71 and sw1881 on SSC 6