Stark shift and parity non-conservation for near-degenerate states of xenon

We identify a pair of near-degenerate states of opposite parity in atomic Xe, the 5p^5 10s \,\, ^2[3/2]_2^o at $\rm{E}=94759.927$ cm$^{-1}$ and 5p^5 6f \,\, ^2[5/2]_2 at $\rm{E}= 94759.935$ cm$^{-1}$, for which parity- and time-odd effects are expected to be enhanced by the small energy separation. We present theoretical calculations which indicate narrow widths for both states and we report a calculated value for the weak matrix element, arising from configuration mixing, of $|W|=2.1$ Hz for $^{132}$Xe. In addition, we measured the Stark effect of the $5p^5\,6f$ $^2[5/2]_{2}$ and $5p^5 \,6f \ ^2[3/2]_2$ ($\rm{E} =94737.121\,\rm{cm}^{-1}$) states. The Stark-shift of the $6f$ states is observed to be negative, revealing the presence of nearby $6g$ states at higher energies, which have not been observed before. The Stark-shift measurements imply an upper limit on the weak matrix element of $|W|\!<\!5$ Hz for the near-degenerate states (10s \,\, ^2[3/2]_2^o and 6f \,\, ^2[5/2]_2), which is in agreement with the presented calculations.Comment: 11 pages, 6 figure

Nondestructive in-line sub-picomolar detection of magnetic nanoparticles in flowing complex fluids

Over the last decades, the use of magnetic nanoparticles in research and commercial applications has increased dramatically. However, direct detection of trace quantities remains a challenge in terms of equipment cost, operating conditions and data acquisition times, especially in flowing conditions within complex media. Here we present the in-line, non-destructive detection of magnetic nanoparticles using high performance atomic magnetometers at ambient conditions in flowing media. We achieve sub-picomolar sensitivities measuring $\sim$30 nm ferromagnetic iron and cobalt nanoparticles that are suitable for biomedical and industrial applications, under flowing conditions in water and whole blood. Additionally, we demonstrate real-time surveillance of the magnetic separation of nanoparticles from water and whole blood. Overall our system has the merit of inline direct measurement of trace quantities of ferromagnetic nanoparticles with so far unreached sensitivities and could be applied in the biomedical field (diagnostics and therapeutics) but also in the industrial sector

Solution nuclear magnetic resonance spectroscopy on a nanostructured diamond chip

Sensors using nitrogen-vacancy centers in diamond are a promising tool for small-volume nuclear magnetic resonance (NMR) spectroscopy, but the limited sensitivity remains a challenge. Here we show nearly two orders of magnitude improvement in concentration sensitivity over previous nitrogen-vacancy and picoliter NMR studies. We demonstrate NMR spectroscopy of picoliter-volume solutions using a nanostructured diamond chip with dense, high-aspect-ratio nanogratings, enhancing the surface area by 15 times. The nanograting sidewalls are doped with nitrogen-vacancies located a few nanometers from the diamond surface to detect the NMR spectrum of roughly 1 pl of fluid lying within adjacent nanograting grooves. We perform 1H and 19F nuclear magnetic resonance spectroscopy at room temperature in magnetic fields below 50 mT. Using a solution of CsF in glycerol, we determine that 4 ± 2 × 1012 19F spins in a 1 pl volume can be detected with a signal-to-noise ratio of 3 in 1 s of integration

Comparing the transcriptomes of embryos from domesticated and wild Atlantic salmon (Salmo salar L.) stocks and examining factors that influence heritability of gene expression

Background&nbsp; Due to selective breeding, domesticated and wild Atlantic salmon are genetically diverged, which raises concerns about farmed escapees having the potential to alter the genetic composition of wild populations and thereby disrupting local adaptation. Documenting transcriptional differences between wild and domesticated stocks under controlled conditions is one way to explore the consequences of domestication and selection. We compared the transcriptomes of wild and domesticated Atlantic salmon embryos, by using a custom 44k oligonucleotide microarray to identify perturbed gene pathways between the two stocks, and to document the inheritance patterns of differentially-expressed genes by examining gene expression in their reciprocal hybrids.&nbsp; Results&nbsp; Data from 24 array interrogations were analysed: four reciprocal cross types (W♀&times;W♂, D♀&times;W♂; W♀&times;D♂, D♀&times;D♂)&times;six biological replicates. A common set of 31,491 features on the microarrays passed quality control, of which about 62% were assigned a KEGG Orthology number. A total of 6037 distinct genes were identified for gene-set enrichment/pathway analysis. The most highly enriched functional groups that were perturbed between the two stocks were cellular signalling and immune system, ribosome and RNA transport, and focal adhesion and gap junction pathways, relating to cell communication and cell adhesion molecules. Most transcripts that were differentially expressed between the stocks were governed by additive gene interaction (33 to 42%). Maternal dominance and over-dominance were also prevalent modes of inheritance, with no convincing evidence for a stock effect.&nbsp; Conclusions&nbsp; Our data indicate that even at this relatively early developmental stage, transcriptional differences exist between the two stocks and affect pathways that are relevant to wild versus domesticated environments. Many of the identified differentially perturbed pathways are involved in organogenesis, which is expected to be an active process at the eyed egg stage. The dominant effects are more largely due to the maternal line than to the origin of the stock. This finding is particularly relevant in the context of potential introgression between farmed and wild fish, since female escapees tend to have a higher spawning success rate compared to males

Método automático de clasificación de color en dientes humanos usando aprendizaje de máquina

Trabajo de InvestigaciónActualmente el proceso de identificación del color de los dientes para la fabricación de prótesis dentales es realizado manualmente por un experto que, utilizando un método de identificación visual, determina el color de las piezas dentales en la boca del paciente, usando guías de color como la VITA®. A pesar de que el método visual es el más utilizado para la identificación del color de dientes, este se ve afectado por distintas variables tales como: el cansancio del experto, la luminosidad en el ambiente, salud visual del especialista, entre otras que influyen en la identificación del color en los dientes. Los errores en la clasificación del color de los dientes pueden generar pérdidas de tiempo lo que implicaría en consecuencia sobrecostos que afectarían directamente al fabricante y la satisfacción final del cliente.1. Planteamiento del problema 2. Pregunta de investigación 3. Objetivos 4. Estado del arte 5. Marco de referencia 6. Alcances y limitaciones 7. Metodología 8. Diseño metodológico 9. Discusión y resultados 10. Conclusiones 11. Trabajos futuros 12. Bibliografía 13. ANEXOSPregradoIngeniero de Sistema

Scope

Scope, later retitled Centerscope, was published by the Boston University Medical Center to report on events at and around the Center

Absolute optical chiral analysis using cavity-enhanced polarimetry

Chiral analysis is central for scientific advancement in the fields of chemistry, biology, and medicine. It is also indispensable in the development and quality control of chiral compounds in the chemical and pharmaceutical industries. Here, we present the concept of absolute optical chiral analysis, as enabled by cavity-enhanced polarimetry, which allows for accurate unambiguous enantiomeric characterization and enantiomeric excess determination of chiral compounds within complex mixtures at trace levels, without the need for calibration, even in the gas phase. Our approach and technology enable the absolute postchromatographic chiral analysis of complex gaseous mixtures, the rapid quality control of complex mixtures containing chiral volatile compounds, and the online in situ observation of chiral volatile emissions from a plant under stress