A fossil byblidaceae seed from eocene South Australia

Copyright © 2004 by The University of ChicagoA single mummified angiosperm seed is described from a middle Eocene clay lens deposit at the Monier East Yatala Sand Pit, Golden Grove, South Australia. The seed is small (0.7 mm long and 0.45 mm wide), elliptical, black, and shows complex raised reticulate honeycomb sculpturing with deeply excavated cell floors and verrucate sculpturing on the anticlinal ridges. The fossil was compared against extant species of Byblis and the Droseraceae, especially the Drosera indica L. complex, common annual carnivorous plants that grow in seasonally damp environments in northern Australia and that have similarly small sculptured seeds. The combination of deep reticulately honeycombed cells and the verrucate anticlinal walls places the seed close to extant taxa in the Byblis liniflora Salisb. complex. However, in the absence of a larger sample and/or of definitive features to assign the fossil unequivocally to an extant species, as well as nomenclatural restrictions preventing the typification of a fossil by an illustration, the specimen is described as a parataxon and placed in Byblidaceae but without a formal name.Conran, John G., and David C. Christophe

View-Independent Working Memory Representations of Artificial Shapes in Prefrontal and Posterior Regions of the Human Brain

Traditional views of visual working memory postulate that memorized contents are stored in dorsolateral prefrontal cortex using an adaptive and flexible code. In contrast, recent studies proposed that contents are maintained by posterior brain areas using codes akin to perceptual representations. An important question is whether this reflects a difference in the level of abstraction between posterior and prefrontal representations. Here we investigated whether neural representations of visual working memory contents are view-independent, as indicated by rotation-invariance. Using fMRI and multivariate pattern analyses, we show that when subjects memorize complex shapes, both posterior and frontal brain regions maintain the memorized contents using a rotation-invariant code. Importantly, we found the representations in frontal cortex to be localized to the frontal eye fields rather than dorsolateral prefrontal cortices. Thus, our results give evidence for the view-independent storage of complex shapes in distributed representations across posterior and frontal brain regions

Cortical specialization for attended versus unattended working memory

Items held in working memory can be either attended or not, depending on their current behavioral relevance. It has been suggested that unattended contents might be solely retained in an activity-silent form. Instead, we demonstrate here that encoding unattended contents involves a division of labor. While visual cortex only maintains attended items, intraparietal areas and the frontal eye fields represent both attended and unattended items

Combined investigation of collective amplitude and phase modes in a quasi-one-dimensional charge-density-wave system over a wide spectral range

We investigate experimentally both the amplitude and phase channels of the collective modes in the quasi-1D charge-density-wave (CDW) system, K0.3MoO3, by combining (i) optical impulsive-Raman pump-probe and (ii) terahertz time-domain spectroscopy (THz-TDS), with high resolution and a detailed analysis of the full complex-valued spectra in both cases. This allows an unequivocal assignment of the observed bands to CDW modes across the THz range up to 9 THz. We revise and extend a time-dependent Ginzburg-Landau model to account for the observed temperature dependence of the modes, where the combination of both amplitude and phase modes allows one to robustly determine the bare-phonon and electron-phonon coupling parameters. While the coupling is indeed strongest for the lowest-energy phonon, dropping sharply for the immediately subsequent phonons, it grows back significantly for the higher-energy phonons, demonstrating their important role in driving the CDW formation. We also include a reassessment of our previous analysis of the lowest-lying phase modes, whereby assuming weaker electronic damping for the phase channel results in a qualitative picture more consistent with quantum-mechanical treatments of the collective modes, with a strongly coupled amplitudon and phason as the lowest modes

Categorical working memory codes in human visual cortex

Working memory contents are represented in neural activity patterns across multiple regions of the cortical hierarchy. A division of labor has been proposed where more anterior regions harbor increasingly abstract and categorical representations while the most detailed representations are held in primary sensory cortices. Here, using fMRI and multivariate encoding modeling, we demonstrate that for color stimuli categorical codes are already present at the level of extrastriate visual cortex (V4 and VO1), even when subjects are neither implicitly nor explicitly encouraged to categorize the stimuli. Importantly, this categorical coding was observed during working memory, but not during perception. Thus, visual working memory is likely to rely at least in part on categorical representations. SIGNIFICANCE STATEMENT: Working memory is the representational basis for human cognition. Recent work has demonstrated that numerous regions across the human brain can represent the contents of working memory. We use fMRI brain scanning and machine learning methods to demonstrate that different regions can represent the same content differently during working memory. Reading out the neural codes used to store working memory contents, we show that already in sensory cortex, areas V4 and VO1 represent color in a categorical format rather than a purely sensory fashion. Thereby, we provide a better understanding of how different regions of the brain might serve working memory and cognition

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Combining regenerative medicine strategies to provide durable reconstructive options: auricular cartilage tissue engineering

Recent advances in regenerative medicine place us in a unique position to improve the quality of engineered tissue. We use auricular cartilage as an exemplar to illustrate how the use of tissue-specific adult stem cells, assembly through additive manufacturing and improved understanding of postnatal tissue maturation will allow us to more accurately replicate native tissue anisotropy. This review highlights the limitations of autologous auricular reconstruction, including donor site morbidity, technical considerations and long-term complications. Current tissue-engineered auricular constructs implanted into immune-competent animal models have been observed to undergo inflammation, fibrosis, foreign body reaction, calcification and degradation. Combining biomimetic regenerative medicine strategies will allow us to improve tissue-engineered auricular cartilage with respect to biochemical composition and functionality, as well as microstructural organization and overall shape. Creating functional and durable tissue has the potential to shift the paradigm in reconstructive surgery by obviating the need for donor sites

Hemolytic dynamics of weekly primaquine antirelapse therapy among Cambodians with acute Plasmodium vivax malaria with or without glucose-6-phosphate dehydrogenase deficiency

Background: Hemoglobin (Hb) data are limited in Southeast Asian glucose-6-phosphate dehydrogenase (G6PD) deficient (G6PD−) patients treated weekly with the World Health Organization–recommended primaquine regimen (ie, 0.75 mg/kg/week for 8 weeks [PQ 0.75]). Methods: We treated Cambodians who had acute Plasmodium vivax infection with PQ0.75 and a 3-day course of dihydroartemisinin/piperaquine and determined the Hb level, reticulocyte count, G6PD genotype, and Hb type. Results: Seventy-five patients (male sex, 63) aged 5–63 years (median, 24 years) were enrolled. Eighteen were G6PD deficient (including 17 with G6PD Viangchan) and 57 were not G6PD deficient; 26 had HbE (of whom 25 were heterozygous), and 6 had α-/β-thalassemia. Mean Hb concentrations at baseline (ie, day 0) were similar between G6PD deficient and G6PD normal patients (12.9 g/dL [range, 9‒16.3 g/dL] and 13.26 g/dL [range, 9.6‒16 g/dL], respectively; P = .46). G6PD deficiency (P = .000), higher Hb concentration at baseline (P = .000), higher parasitemia level at baseline (P = .02), and thalassemia (P = .027) influenced the initial decrease in Hb level, calculated as the nadir level minus the baseline level (range, −5.8–0 g/dL; mean, −1.88 g/dL). By day 14, the mean difference from the day 7 level (calculated as the day 14 level minus the day 7 level) was 0.03 g/dL (range, −0.25‒0.32 g/dL). Reticulocyte counts decreased from days 1 to 3, peaking on day 7 (in the G6PD normal group) and day 14 (in the G6PD deficient group); reticulocytemia at baseline (P = .001), G6PD deficiency (P = .000), and female sex (P = .034) correlated with higher counts. One symptomatic, G6PD-deficient, anemic male patient was transfused on day 4. Conclusions: The first PQ0.75 exposure was associated with the greatest decrease in Hb level and 1 blood transfusion, followed by clinically insignificant decreases in Hb levels. PQ0.75 requires monitoring during the week after treatment. Safer antirelapse regimens are needed in Southeast Asia

Undergraduate medical research: the student perspective

Background: Research training is essential in a modern undergraduate medical curriculum. Our evaluation aimed to (a) gauge students’ awareness of research activities, (b) compare students’ perceptions of their transferable and research-specific skills competencies, (c) determine students’ motivation for research and (d) obtain students’ personal views on doing research. Methods: Undergraduate medical students (N=317) completed a research skills questionnaire developed by the Centre for Excellence in Teaching and Learning in Applied Undergraduate Research Skills (CETL-AURS) at Reading University. The questionnaire assessed students’ transferable skills, research-specific skills (e.g., study design, data collection and data analysis), research experience and attitude and motivation towards doing research. Results: The majority of students are motivated to pursue research. Graduate entrants and male students appear to be the most confident regarding their research skills competencies. Although all students recognise the role of research in medical practice, many are unaware of the medical research activities or successes within their university. Of those who report no interest in a career incorporating research, a common perception was that researchers are isolated from patients and clinical practice. Discussion: Students have a narrow definition of research and what it entails. An explanation for why research competence does not align more closely with research motivation is derived from students’ lack of understanding of the concept of translational research, as well as a lack of awareness of the research activity being undertaken by their teachers and mentors. We plan to address this with specific research awareness initiatives