Perithecial ascomycetes from the 400 million year old Rhynie chert: an example of ancestral polymorphism

We describe a perithecial, pleomorphic ascomycetous fungus from the Early Devonian (400 mya) Rhynie chert; the fungus occurs in the cortex just beneath the epidermis of aerial stems and rhizomes of the vascular plant Asteroxylon. Perithecia are nearly spherical with a short, ostiolate neck that extends into a substomatal chamber of the host plant; periphyses line the inner surface of the ostiole. The ascocarp wall is multilayered and formed of septate hyphae; extending from the inner surface are elongate asci interspersed with delicate paraphyses. Asci appear to be unitunicate and contain up to 16 smooth, uniseriate-biseriate ascospores. The method of ascospore liberation is unknown; however, the tip of the ascus is characterized by a narrow, slightly elevated circular collar. Ascospores appear 1–5 celled, and germination is from one end of the spore. Also present along the stems and interspersed among the perithecia are acervuli of conidiophores that are interpreted as the anamorph of the fungus. Conidiogenesis is thallic, basipetal and probably of the holoarthric-type; arthrospores are cube-shaped. Some perithecia contain mycoparasites in the form of hyphae and thick-walled spores of various sizes. The structure and morphology of the fossil fungus is compared with modern ascomycetes that produce perithecial ascocarps, and characters that define the fungus are considered in the context of ascomycete phylogeny

Evaluation of insect-mediated seed set among soybean lines segregating for male sterility at the ms6 locus

Currently, there is no economical way to produce large quantities of F1 hybrid soybean seed in the USA. One of the fundamental requirements for hybrid seed production is the availability of a stable male-sterile, female-fertile system. However, the more challenging barrier is the efficient transfer of pollen from the male parent to the female parent. This could potentially be achieved through pollinator insects. Our observations suggested that seed set on male-sterile, female-fertile plants is a good indicator of insect attraction. The objective of this study was to evaluate seed set among male-sterile, female-fertile lines segregating for male-sterile, female-fertile ms6 allele by using Megachile rotundata as pollinator vector. Thirty-four pairs of near-isogenic lines, the ms6 w1w1 donor parent, and its two isogenic lines W1w1 and w1w1 segregating for male-sterile (ms6) allele were used. The W1 locus controls flower color and hypocotyle pigmentation. Seed set was evaluated on field-grown plants in 2001–2003 near Ames, IA. Although the observed seed set was not commercially acceptable, our results indicated significant differences in seed set among lines. This suggests that preferential attraction of pollinators occurred, and selection among male-sterile, female-fertile lines could be used to obtain female parents suitable to produce larger amounts of hybrid soybean seed. In addition, the effect of flower color on seed set was statistically significant. White-flowered lines (w1w1) produced more seed set compared to purple-flowered lines (W1W1). Lastly, the important effect of year suggested that the effect of environmental conditions on seed set among lines segregating for male sterility was of paramount importance to plant–pollinator interactions. This needs to be assessed in order to establish an efficient hybrid soybean progra

Insect-mediated seed-set evaluation of 21 soybean lines segregating for male sterility at 10 different loci

The first requirement to establish a successful hybrid soybean program is the availability of a stable male-sterile, female-fertile system. Male sterility has been an important tool in soybean breeding programs to improve traits such as yield, seed-protein and seed-oil content, and seed size. However, improvement of seed-set per se on male-sterile plants has not been an important breeding objective. The evaluation of the out-crossing potential of the available male-sterile, female-fertile soybean lines is crucial to determine the future of hybrid soybean. The objective of this study was to evaluate seed-set among 21 soybean lines segregating for male sterility at 10 different loci usingMegachile rotundata as insect pollinator. Seed-set was evaluated in field conditions in 2001, 2002, and 2003 near Ames, Iowa. Our results indicated significant differences in seed-set among male-sterile lines. The effects of maturity group, pubescence color, the locus and/or the allele, and the genetic background of the lines segregating for male sterility were significant. Differences for seed-set among lines with independent mutational events at the same locus, (i.e. different alleles), also were significant. These results imply that interaction effects with the genetic background of the lines for traits related to fertility/sterility and insect-pollinator attraction and reward are important. Flower color had little effect on seed-set in the evaluated lines. The effect of year was very important on the performance of the lines for seed-set. This suggested that environmental conditions that favor plant–pollinator relationships need to be determined in order to increase insect-mediated cross-pollination to develop an efficient hybrid soybean program

Predicting running away in girls who are victims of commercial sexual exploitation

Youth that are victims of commercial sexual exploitation of children (CSEC) have a host of clinical problems and often run away from home, residential care, and treatment, which complicates and limits treatment effectiveness. No research to date has attempted to predict running away in CSEC victims. The present study aimed to 1) characterize a clinically referred sample of girls who were victims of CSEC and compare them to other high-risk girls (i.e., girls who also have a history of trauma and running away, but deny CSEC); and 2) examine the utility of using the Youth Level of Service/Case Management Inventory (YLS/CMI) to predict future running away. Data were collected from de-identified charts of 80 girls (mean age = 15.38, SD = 1.3, 37.9% White, 52.5% CSEC victims) who were referred for psychological assessment by the Department of Child Services. Girls in the CSEC group were more likely to have experienced sexual abuse (χ2 = 6.85, p = .009), an STI (χ2 = 6.45, p = .01), a post-traumatic stress disorder diagnosis (χ2 = 11.84, p = .001), and a substance use disorder diagnosis (χ2 = 11.32, p = .001) than high-risk girls. Moderated regression results indicated that YLS/CMI scores significantly predicted future running away among the CSEC group (β = 0.23, SE = .06, p = .02), but not the high-risk group (β = -.008, SE = .11, p =.90). The YLS/CMI shows initial promise for predicting future running away in girls who are CSEC victims. Predicting running away can help identify those at risk for and prevent running away and improve treatment outcomes. We hope current findings stimulate future work in this area

Tuning crystallographic compatibility to enhance shape memory in ceramics

The extraordinary ability of shape-memory alloys to recover after large imposed deformation motivates efforts to transpose these properties onto ceramics, which would enable practical shape-memory properties at high temperatures and in harsh environments. The theory of mechanical compatibility was utilized to predict promising ceramic candidates in the system (Y_(0.5)Ta_(0.5)O_2)_(1−x)−(Zr_(0.5)Hf_(0.5)O_2)_x, 0.6< x < 0.85. When these compatibility conditions are met, a reduction in thermal hysteresis by a factor of 2.5, a tripling of deformability, and a 75% enhancement in strain recovery within the shape-memory effect was found. These findings reveal that predicting and optimizing the chemical composition of ceramics to attain improved crystallographic compatibility is a powerful tool for enabling and enhancing their deformability that could ultimately lead to a highly reversible oxide ceramic shape-memory material

Imaging technology in mice enhances human brain research

Photoacoustic tomography offering a large field of view and high spatial resolution enables, for the first time, noninvasive imaging of resting-state functional connectivity in the murine brain

Seed-set evaluation of four male-sterile, female-fertile soybean lines using alfalfa leafcutting bees and honey bees as pollinators

Male-sterile, female-fertile plants were used to produce hybrid soybean seed. Manual cross-pollination using male-sterile plants to produce large quantities of hybrid seed is difficult and time-consuming because of the low success rate in cross-pollination. Insect pollinators may be suitable vectors to transfer pollen, but the most suitable vector for pollen transfer from the male parent to the female parent has not been identified for soybean. The objective of the present study was to evaluate seed-set on four male-sterile, female-fertile soybean lines by using alfalfa leafcutting bees (Megachile rotundata (F.)) and honey bees (Apis mellifera (L.)) as pollinators. Seed-set was evaluated in summers 2003 and 2005 near Ames, Iowa, USA and in summers 2003, 2004, and 2005 near Wooster, Ohio, USA. Neither the effect of pollinator species nor the interaction effect of pollinator species×location was significant for any year. Honey bees performed similarly to alfalfa leafcutting bees at both locations. The results indicated significant differences for seed-set among male-sterile lines, suggesting preferential pollination. Male-sterile lines, ms1(Urbana) and ms2 (Ames 2), had higher cross-pollinated seed-set compared to ms6 (Ames 1), and ms6 (Corsoy 79). At the Ames location, ms1ms1 (Urbana) plants had the highest seed-set (50·16 seeds per male-sterile plant in 2005). At the Wooster location, ms1ms1 (Urbana) plants also had the highest seed-set (92·04 seeds per male-sterile plant) in 2005. Costs and local conditions need to be addressed to support the choice of either pollinator species as a pollination vector to produce hybrid soybean seed

Paths to light trapping in thin film GaAs solar cells

It is now well established that light trapping is an essential element of thin film solar cell design. Numerous light trapping geometries have already been applied to thin film cells, especially to silicon-based devices. Less attention has been paid to light trapping in GaAs thin film cells, mainly because light trapping is considered less attractive due to the material's direct bandgap and the fact that GaAs suffers from strong surface recombination, which particularly affects etched nanostructures. Here, we study light trapping structures that are implemented in a high-bandgap material on the back of the GaAs active layer, thereby not perturbing the integrity of the GaAs active layer. We study photonic crystal and quasi-random nanostructures both by simulation and by experiment and find that the photonic crystal structures are superior because they exhibit fewer but stronger resonances that are better matched to the narrow wavelength range where GaAs benefits from light trapping. In fact, we show that a 1500 nm thick cell with photonic crystals achieves the same short circuit current as an unpatterned 4000 nm thick cell. These findings are significant because they afford a sizeable reduction in active layer thickness, and therefore a reduction in expensive epitaxial growth time and cost, yet without compromising performance