The labial gene is required to terminate proliferation of identified neuroblasts in postembryonic development of the Drosophila brain

The developing brain of Drosophila has become a useful model for studying the molecular genetic mechanisms that give rise to the complex neuronal arrays that characterize higher brains in other animals including mammals. Brain development in Drosophila begins during embryogenesis and continues during a subsequent postembryonic phase. During embryogenesis, the Hox gene labial is expressed in the developing tritocerebrum, and labial loss-of-function has been shown to be associated with a loss of regional neuronal identity and severe patterning defects in this part of the brain. However nothing is known about the expression and function of labial, or any other Hox gene, during the postembryonic phase of brain development, when the majority of the neurons in the adult brain are generated. Here we report the first analysis of Hox gene action during postembryonic brain development in Drosophila. We show that labial is initially expressed in six larval brain neuroblasts, of which only four give rise to the labial expressing neuroblast lineages present in the late larval brain. Although MARCM-based clonal mutation of labial in these four neuroblast lineages does not result in an obvious phenotype, a striking and unexpected effect of clonal labial loss-of-function does occur during postembryonic brain development, namely the formation of two ectopic neuroblast lineages that are not present in wild-type brains. The same two ectopic neuroblast lineages are also observed following cell death blockage and, significantly, in this case the resulting ectopic lineages are Labial-positive. These findings imply that labial is required in two specific neuroblast lineages of the wildtype brain for the appropriate termination of proliferation through programmed cell death. Our analysis of labial function reveals a novel cell autonomous role of this Hox gene in shaping the lineage architecture of the brain during postembryonic development

Anomalously large capacitance of a plane capacitor with a two-dimensional electron gas

In electronic devices where a two-dimensional electron gas (2DEG) comprises one or both sides of a plane capacitor, the resulting capacitance $C$ can be larger than the "geometric capacitance" $C_g$ determined by the physical separation $d$ between electrodes. This larger capacitance is known to result from the Coulomb correlations between individual electrons within the low density 2DEG, which lead to a negative thermodynamic density of states (negative compressibility). Experiments on such systems generally operate in the regime where the average spacing between electrons $n^{-1/2}$ in the 2DEG is smaller than $d$, and these experiments observe $C > C_g$ by only a few percent. A recent experiment [1], however, has observed $C$ larger than $C_g$ by almost 40% while operating in the regime $nd^2 << 1$. In this paper we argue that at $nd^2 << 1$ correlations between the electronic charge of opposite electrodes become important. We develop a theory of the capacitance for the full range of $nd^2$. We show that, in the absence of disorder, the capacitance can be $4d/a$ times larger than the geometric value, where $a << d$ is the electron Bohr radius. Our results compare favorably with the experiment of Ref. [1] without the use of adjustable parameters.Comment: 8 pages, 6 figures; revised discussion of the zero density limit; some typos fixe

Towards a single-photon energy-sensitive pixel readout chip: pixel level ADCs and digital readout circuitry

Unlike conventional CMOS imaging, a single\ud photon imager detects each individual photon impinging on\ud a detector, accumulating the number of photons during a\ud certain time window and not the charge generated by the all\ud the photons hitting the detector during said time window.\ud The latest developments in the semiconductor industry\ud are allowing faster and more complex chips to be designed\ud and manufactured. With these developments in mind we are\ud working towards the next step in single photon X-ray imaging:\ud energy sensitive pixel readout chips. The goal is not only\ud to detect and count individual photons, but also to measure\ud the charge deposited in the detector by each photon, and\ud consequently determine its energy. Basically, we are aiming\ud at a spectrometer-in-a-pixel, or a “color X-ray camera”.\ud The approach we have followed towards this goal is the\ud design of small analog-to-digital-converters at the pixel level,\ud together with a very fast digital readout from the pixels to\ud the periphery of the chip, where the data will be transmitted\ud off-chip.\ud We will present here the design and measurement on prototype\ud chips of two different 4-bit pixel level ADCs. The\ud ADCs are optimized for very small area and low power, with\ud a resolution of 4-bits and a sample rate of 1 Msample/s. The\ud readout architecture is based around current-mode sense\ud amplifiers and asynchronous token-passing between the pixels.\ud This is done in order to achieve event-by-event readout\ud and, consequently, on-line imaging. We need to read eventby-\ud event (photon-by-photon), because we cannot have memory\ud on the pixels due to obvious size constraints. We use\ud current-mode sense amplifiers because they perform very\ud well in similar applications as very fast static-RAM readout

Measuring gender norms about relationships in early adolescence : results from the global early adolescent study

Introduction: Gender norms are increasingly recognized as drivers of health and wellbeing. While early adolescence constitutes a critical window of development, there is limited understanding about how adolescents perceive gender relations across different cultural settings. This study used a mixed-method approach, grounded in the voices of young people around the world, to construct and test a cross-cultural scale assessing the perceptions of gender norms regulating romantic relationships between boys and girls in early adolescence. Methods: The study draws on the Global Early Adolescent study (GEAS), a study focusing on gender norms and health related outcomes over the course of adolescence in urban poor settings worldwide. In-depth interviews were first conducted among approximately 200 adolescents between 10-14 years in seven sites across 4 continents to identify common scripts guiding romantic relations in early adolescence. These scripts were then transformed into a multidimensional scale. The scale was tested among 120 adolescents in each of 14 GEAS sites, followed by a second pilot among 75 adolescents in six sites. We evaluated the psychometric criteria of each subscale using principal component analysis, and parallel analysis, followed by exploratory factor analysis to guide the selection of a more parsimonious set of items. Results: Results suggested a two-factor structure, consisting of an "adolescent romantic expectations" subscale and a "Sexual Double Standard" subscale. Both subscales yielded high internal validity in each site, with polychoric Cronbach alpha values above 0.70 with the exception of Kinshasa for the adolescent romantic expectations scale (0.64) and Hanoi for the sexual double standard scale (0.61). Conclusion: This study reveals common perceptions of gendered norms about romantic engagement in early adolescence, normative for both sexes, but socially valued for boys while devaluated for girls. The findings illustrate that social hierarchies of power in romantic relationships form early in adolescence, regardless of cultural setting

On the Formation Height of the SDO/HMI Fe 6173 Doppler Signal

The Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) is designed to study oscillations and the mag- netic field in the solar photosphere. It observes the full solar disk in the Fe I absorption line at 6173\AA . We use the output of a high-resolution 3D, time- dependent, radiation-hydrodynamic simulation based on the CO5BOLD code to calculate profiles F({\lambda},x,y,t) for the Fe I 6173{\AA} line. The emerging profiles F({\lambda},x,y,t) are multiplied by a representative set of HMI filter transmission profiles R_i({\lambda},1 \leq i \leq 6) and filtergrams I_i(x,y,t;1 \leq i \leq 6) are constructed for six wavelengths. Doppler velocities V_HMI(x,y,t) are determined from these filtergrams using a simplified version of the HMI pipeline. The Doppler velocities are correlated with the original velocities in the simulated atmosphere. The cross- correlation peaks near 100 km, suggesting that the HMI Doppler velocity signal is formed rather low in the solar atmosphere. The same analysis is performed for the SOHO/MDI Ni I line at 6768\AA . The MDI Doppler signal is formed slightly higher at around 125 km. Taking into account the limited spatial resolution of the instruments, the apparent formation height of both the HMI and MDI Doppler signal increases by 40 to 50 km. We also study how uncertainties in the HMI filter-transmission profiles affect the calculated velocities.Comment: 15 pages, 11 Figure

Confidence regions for neutrino oscillation parameters from double-Chooz data

In this work, an independent and detailed statistical analysis of the double-Chooz experiment is performed. To have a thorough understanding of the implications of the double-Chooz data on both oscillation parameters $\sin^{2}(2\theta_{13})$ and $\Delta m^2_{31}$, we decided to analyze the data corresponding to the Far detector, with no additional restriction. By doing this, confidence regions and best fit values are obtained for ($\sin^{2}(2\theta_{13}),\Delta m^2_{31}$). This analysis yields an out-of-order $\Delta m^2_{31}$ minimum, which has already been mentioned in previous works, and it is corrected with the inclusion of additional restrictions. With such restrictions it is obtained that $\sin ^{2}(2 \theta _{13})=0{.}084_{-0{.}028}^{+0{.}030}$ and $\Delta m^2_{31}=2.444^{+0.187}_{-0.215} \times 10^{-3}$ eV$^2$/c$^4$. Our analysis allows us to study the effects of the so called "spectral bump" around 5 MeV, it is observed that a variation of this spectral bump may be able to move the $\Delta m^2_{31}$ best fit value, in such a way that $\Delta m^2_{31}$ takes the order of magnitude of the MINOS value. Finally, and with the intention of understanding the effects of the preliminary Near detector data, we performed two different analyses, aiming to eliminate the effects of the energy bump. As a consequence, it is found that unlike the Far Detector analysis, the Near detector data may be able to fully determine both oscillation parameters by itself, resulting in, $\sin^2(2\theta_{13}) = 0.095 \pm 0.053$ and $\Delta m^{2}_{31} = 2.63^{+0.98}_{-1.15} \times 10^{-3} \text{eV}^2 / \text{c}^4$. The later analyses represent an improvement with respect to previous works, where additional constraints for $\Delta m^2_{31}$ were necessary.Comment: 11 pages, 2 b/n figure, 5 color figures, 6 table

A MegaCam Survey of Outer Halo Satellites. VII. A Single S\'ersic Index v/s Effective Radius Relation for Milky Way Outer Halo Satellites

In this work we use structural properties of Milky Way's outer halo ($R_G > 25\,\mathrm{kpc}$) satellites (dwarf spheroidal galaxies, ultra-faint dwarf galaxies and globular clusters) derived from deep, wide-field and homogeneous data, to present evidence of a correlation in the S\'ersic index v/s effective radius plane followed by a large fraction of outer halo globular clusters and satellite dwarf galaxies. We show that this correlation can be entirely reproduced by fitting empirical relations in the central surface brightness v/s absolute magnitude and S\'ersic index v/s absolute magnitude parameter spaces, and by assuming the existence of two types of outer halo globular clusters: one of high surface brightness (HSB group), with properties similar to inner halo clusters; and another of low surface brightness (LSB group), which share characteristics with dwarf spheroidal and ultra-faint dwarf galaxies. Given the similarities of LSB clusters with dwarf spheroidal and ultra-faint dwarf galaxies, we discuss the possibility that outer halo clusters also originated inside dark matter halos and that tidal forces from different galaxy host's potentials are responsible for the different properties between HSB and LSB clusters.Comment: 20 pages, 9 figures, 3 table

Raman spectroscopy of InN films grown on Si

We have used Raman spectroscopy to study indium nitride thin films grown by molecular beam epitaxy on (111) silicon substrates at temperatures between 450 and 550 C. The Raman spectra show well defined peaks at 443, 475, 491, and 591 cm{-1}, which correspond to the A_1(TO), E_1(TO), E_2^{high}, and A_1(LO) phonons of the wurtzite structure, respectively. In backscattering normal to the surface the A_1(TO) and E_1(TO) peaks are very weak, indicating that the films grow along the hexagonal c axis. The dependence of the peak width on growth temperature reveals that the optimum temperature is 500 C, for which the fullwidth of the E_2^{high} peak has the minimum value of 7 cm{-1}. This small value, comparable to previous results for InN films grown on sapphire, is evidence of the good crystallinity of the films.Comment: 3 pages, 1 eps figure, RevTe

Growth Pattern of Pseudomonas aeruginosa in different wastewater media

Restaurant wastewater are a major cause of environmental pollution with the indiscriminate release of the effluent to the environment resulting in blocking of drainages and eutrophication thereby causing serious threat to aquatic life. The growth pattern of a dietary rich oily wastewater degrading bacteria strain, Pseudomonas aeruginosa in different wastewater media composed to mimic the possible constituents of restaurant wastewater was investigated in this study. There was noticeable microbial growth in the synthetic and domestic wastewaters after 48h while the detergent wastewater and heated oil-detergent wastewater did not support the strain's growth. The decrease in the fat content with a corresponding increase in the ash content after 120h was due to the test strain's metabolic activity, which is slightly higher in domestic wastewater than the heated oil-detergent solution. Also, the potassium (K+), Mg2+, Fe2+ and Ca2+ contents increased within the same period in both media except in the domestic wastewater where the Ca2+ content reduced. Protease enzyme activity (46.440mM/min) was considerably higher in the domestic wastewater than lipase (3.322mM/min) and amylase activity (14.244mM/min) after 72 hours of incubation. The pristine genetic properties of Pseudomonas aeruginosa altered when cultured in various wastewaters probably due to variation in the composition of the substrates