3,540 research outputs found
Synaptic plasticity, but not hippocampal neurogenesis, mediated the counteractive effect of wolfberry on depression in rats
published_or_final_versio
Luminescent zinc(ii) and copper( i) complexes for high-performance solution-processed monochromic and white organic light-emitting devices
published_or_final_versio
Controllability and controller-observer design for a class of linear time-varying systems
“The final publication is available at Springer via http://dx.doi.org/10.1007/s10852-012-9212-6"In this paper a class of linear time-varying control systems is considered. The time variation consists of a scalar time-varying coefficient multiplying the state matrix of an otherwise time-invariant system. Under very weak assumptions of this coefficient, we show that the controllability can be assessed by an algebraic rank condition, Kalman canonical decomposition is possible, and we give a method for designing a linear state-feedback controller and Luenberger observer
Plasma-Induced Frequency Chirp of Intense Femtosecond Lasers and Its Role in Shaping High-Order Harmonic Spectral Lines
We investigate the self-phase modulation of intense femtosecond laser pulses
propagating in an ionizing gas and its effects on collective properties of
high-order harmonics generated in the medium. Plasmas produced in the medium
are shown to induce a positive frequency chirp on the leading edge of the
propagating laser pulse, which subsequently drives high harmonics to become
positively chirped. In certain parameter regimes, the plasma-induced positive
chirp can help to generate sharply peaked high harmonics, by compensating for
the dynamically-induced negative chirp that is caused by the steep intensity
profile of intense short laser pulses.Comment: 5 pages, 5 figure
Overcoming cross-cultural group work tensions: mixed student perspectives on the role of social relationships
As universities worldwide rapidly internationalise, higher education classrooms have become unique spaces for collaboration between students from different countries. One common way to encourage collaboration between diverse peers is through group work. However, previous research has highlighted that cross-cultural group work can be challenging and has hinted at potential social tensions. To understand this notion better, we have used robust quantitative tools in this study to select 20 participants from a larger classroom of 860 students to take part in an in-depth qualitative interview about cross-cultural group work experiences. Participant views on social tensions in cross-cultural group work were elicited using a unique mediating artefact method to encourage reflection and in-depth discussion. In our analysis of emergent interview themes, we compared student perspectives on the role of social relationships in group work by their academic performance level. Our findings indicated that all students interviewed desired the opportunity to form social relationships with their group work members, but their motivations for doing so varied widely by academic performance level
Cough quality in children: a comparison of subjective vs. bronchoscopic findings
BACKGROUND: Cough is the most common symptom presenting to doctors. The quality of cough (productive or wet vs dry) is used clinically as well as in epidemiology and clinical research. There is however no data on the validity of cough quality descriptors. The study aims were to compare (1) cough quality (wet/dry and brassy/non-brassy) to bronchoscopic findings of secretions and tracheomalacia respectively and, (2) parent's vs clinician's evaluation of the cough quality (wet/dry). METHODS: Cough quality of children (without a known underlying respiratory disease) undergoing elective bronchoscopy was independently evaluated by clinicians and parents. A 'blinded' clinician scored the secretions seen at bronchoscopy on pre-determined criteria and graded (1 to 6). Kappa (K) statistics was used for agreement, and inter-rater and intra-rater agreement examined on digitally recorded cough. A receiver operating characteristic (ROC) curve was used to determine if cough quality related to amount of airway secretions present at bronchoscopy. RESULTS: Median age of the 106 children (62 boys, 44 girls) enrolled was 2.6 years (IQR 5.7). Parent's assessment of cough quality (wet/dry) agreed with clinicians' (K = 0.75, 95%CI 0.58–0.93). When compared to bronchoscopy (bronchoscopic secretion grade 4), clinicians' cough assessment had the highest sensitivity (0.75) and specificity (0.79) and were marginally better than parent(s). The area under the ROC curve was 0.85 (95%CI 0.77–0.92). Intra-observer (K = 1.0) and inter-clinician agreement for wet/dry cough (K = 0.88, 95%CI 0.82–0.94) was very good. Weighted K for inter-rater agreement for bronchoscopic secretion grades was 0.95 (95%CI 0.87–1). Sensitivity and specificity for brassy cough (for tracheomalacia) were 0.57 and 0.81 respectively. K for both intra and inter-observer clinician agreement for brassy cough was 0.79 (95%CI 0.73–0.86). CONCLUSIONS: Dry and wet cough in children, as determined by clinicians and parents has good clinical validity. Clinicians should however be cognisant that children with dry cough may have minimal to mild airway secretions. Brassy cough determined by respiratory physicians is highly specific for tracheomalacia
Vacuolin-1 potently and reversibly inhibits autophagosome-lysosome fusion by activating RAB5A
published_or_final_versio
Naturalness bounds in extensions of the MSSM without a light Higgs boson
Adopting a bottom-up point of view, we make a comparative study of the
simplest extensions of the MSSM with extra tree level contributions to the
lightest Higgs boson mass. We show to what extent a relatively heavy Higgs
boson, up to 200-350 GeV, can be compatible with data and naturalness. The
price to pay is that the theory undergoes some change of regime at a relatively
low scale. Bounds on these models come from electroweak precision tests and
naturalness, which often requires the scale at which the soft terms are
generated to be relatively low.Comment: 18 pages, 5 figures. v2: minor revision, added references. v3,v4:
some numerical correction
Haploinsufficient Bmp4 ocular phenotypes include anterior segment dysgenesis with elevated intraocular pressure
BACKGROUND: Glaucoma is a blinding disease usually associated with high intraocular pressure (IOP). In some families, abnormal anterior segment development contributes to glaucoma. The genes causing anterior segment dysgenesis and glaucoma in most of these families are not identified and the affected developmental processes are poorly understood. Bone morphogenetic proteins (BMPs) participate in various developmental processes. We tested the importance of Bmp4 gene dosage for ocular development and developmental glaucoma. RESULTS: Bmp4(+/-) mice have anterior segment abnormalities including malformed, absent or blocked trabecular meshwork and Schlemm's canal drainage structures. Mice with severe drainage structure abnormalities, over 80% or more of their angle's extent, have elevated IOP. The penetrance and severity of abnormalities is strongly influenced by genetic background, being most severe on the C57BL/6J background and absent on some other backgrounds. On the C57BL/6J background there is also persistence of the hyaloid vasculature, diminished numbers of inner retinal cells, and absence of the optic nerve. CONCLUSIONS: We demonstrate that heterozygous deficiency of BMP4 results in anterior segment dysgenesis and elevated IOP. The abnormalities are similar to those in human patients with developmental glaucoma. Thus, BMP4 is a strong candidate to contribute to Axenfeld-Rieger anomaly and other developmental conditions associated with human glaucoma. BMP4 also participates in posterior segment development and wild-type levels are usually critical for optic nerve development on the C57BL/6J background. Bmp4(+/-) mice are useful for studying various components of ocular development, and may allow identification of strain specific modifiers affecting a variety of ocular phenotypes
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