543 research outputs found
Kelvin Probe Studies of Cesium Telluride Photocathode for AWA Photoinjector
Cesium telluride is an important photocathode as an electron source for
particle accelerators. It has a relatively high quantum efficiency (>1%), is
sufficiently robust in a photoinjector, and has a long lifetime. This
photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA)
beamline to produce high charge per bunch (~50 nC) in a long bunch train. Here,
we present a study of the work function of cesium telluride photocathode using
the Kelvin Probe technique. The study includes an investigation of the
correlation between the quantum efficiency and the work function, the effect of
photocathode aging, the effect of UV exposure on the work function, and the
evolution of the work function during and after photocathode rejuvenation via
heating.Comment: 5 pages, 6 figure
The Prevalence of Hyperpalatable Baby Foods and Exposure During Infancy: A Preliminary Investigation
Objective: To characterize the prevalence of hyperpalatable foods (HPF) among baby foods in the U.S. and examine the prevalence of HPF exposure and consumption from both baby food and adult food sources among infants aged 9–15 months.
Methods: A U.S. baby food database as well as baby foods from three 24-h dietary recalls of 147 infants were used to identify baby foods as HPF per previous publication. HPF exposure was defined as intake of any HPF during the 3-day measurement period. To determine the extent of HFP consumption, % kilocalorie (kcal) intake from HPF was characterized.
Results: Only 12% of baby foods were HPF; however, nearly all participants (>90%) consumed HPF, primarily through exposure to adult foods. Younger infants (<12 months) consumed 38% [standard deviation (SD) = 23.6%] of their daily food kcal from HPF and older infants (≥12 months) consumed 52% (SD = 16.4%) of daily food kilocalorie from HPF. Most younger infants (68%) and older infants (88%) had repeated exposure to the same HPF across the measurement period.
Conclusions: The prevalence of HPF among baby foods in the U.S. is low. However, almost all infants were exposed to HPF, and HPF comprised a substantial percentage of daily food kilocalorie in infants' diets. Findings highlight the transition to solid food consumption during complimentary feeding period is a critical time for early HPF exposure
Juego simbólico y la autonomía de los niños de 5 años de la I.E.P. Play House School, Chorrillos, Lima, 2022
La presente investigación aborda la autonomía infantil como una condición
para alcanzar competencias con un alto grado de complejidad y del pensamiento,
además del juego simbólico como estrategia para desarrollarlo en la escuela, por lo
que se planteó como objetivo , para los cual se utilizó una metodología con enfoque
cuantitativo, de tipo básica, con diseño no experimental – correlacional, la muestra
estuvo conformada por 25 niños y niñas de 5 años, el instrumento utilizado para el
recojo de información fueron una lista de cotejo para cada variable, construida por
las autoras. Se tuvo como resultados que respecto a la variable juego simbólico el
72% de los estudiantes se ubicaron el nivel logrado y un 28%, en inicio; por otro
lado, el 76% de ellos se ubicaron en el nivel logrado y un 24%, en el nivel Inicio
respecto a la autonomía. Se concluye que se verificó la correlación positiva y fuerte
del juego simbólico y la autonomía de los niños y niñas de 5 años, mediante la
correlación de Spearman de 0.901, con un p=0.000 siendo menor que el 0.05; esta
correspondencia, revela una relación directamente proporcional entre el juego
simbólico y la autonomía, desde el sustento teórico, práctico y estadístico,
evidenciando también la validez de la lista de cotejo como instrumento, que puede
ser utilizado y adecuado en otras investigaciones considerando el contexto donde
se realiza la misma
Recurrent pregnancy loss is associated with a pro-senescent decidual response during the peri-implantation window
During the implantation window, the endometrium becomes poised to transition to a pregnant state, a process driven by differentiation of stromal cells into decidual cells (DC). Perturbations in this process, termed decidualization, leads to breakdown of the feto-maternal interface and miscarriage, but the underlying mechanisms are poorly understood. Here, we reconstructed the decidual pathway at single-cell level in vitro and demonstrate that stromal cells first mount an acute stress response before emerging as DC or senescent DC (snDC). In the absence of immune cell-mediated clearance of snDC, secondary senescence transforms DC into progesterone-resistant cells that abundantly express extracellular matrix remodelling factors. Additional single-cell analysis of midluteal endometrium identified DIO2 and SCARA5 as marker genes of a diverging decidual response in vivo. Finally, we report a conspicuous link between a pro-senescent decidual response in peri-implantation endometrium and recurrent pregnancy loss, suggesting that pre-pregnancy screening and intervention may reduce the burden of miscarriage
Single-nucleus RNA-seq identifies divergent populations of FSHD2 myotube nuclei.
FSHD is characterized by the misexpression of DUX4 in skeletal muscle. Although DUX4 upregulation is thought to be the pathogenic cause of FSHD, DUX4 is lowly expressed in patient samples, and analysis of the consequences of DUX4 expression has largely relied on artificial overexpression. To better understand the native expression profile of DUX4 and its targets, we performed bulk RNA-seq on a 6-day differentiation time-course in primary FSHD2 patient myoblasts. We identify a set of 54 genes upregulated in FSHD2 cells, termed FSHD-induced genes. Using single-cell and single-nucleus RNA-seq on myoblasts and differentiated myotubes, respectively, we captured, for the first time, DUX4 expressed at the single-nucleus level in a native state. We identified two populations of FSHD myotube nuclei based on low or high enrichment of DUX4 and FSHD-induced genes ("FSHD-Lo" and "FSHD Hi", respectively). FSHD-Hi myotube nuclei coexpress multiple DUX4 target genes including DUXA, LEUTX and ZSCAN4, and also upregulate cell cycle-related genes with significant enrichment of E2F target genes and p53 signaling activation. We found more FSHD-Hi nuclei than DUX4-positive nuclei, and confirmed with in situ RNA/protein detection that DUX4 transcribed in only one or two nuclei is sufficient for DUX4 protein to activate target genes across multiple nuclei within the same myotube. DUXA (the DUX4 paralog) is more widely expressed than DUX4, and depletion of DUXA suppressed the expression of LEUTX and ZSCAN4 in late, but not early, differentiation. The results suggest that the DUXA can take over the role of DUX4 to maintain target gene expression. These results provide a possible explanation as to why it is easier to detect DUX4 target genes than DUX4 itself in patient cells and raise the possibility of a self-sustaining network of gene dysregulation triggered by the limited DUX4 expression
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Computational cytometer based on magnetically modulated coherent imaging and deep learning.
Detecting rare cells within blood has numerous applications in disease diagnostics. Existing rare cell detection techniques are typically hindered by their high cost and low throughput. Here, we present a computational cytometer based on magnetically modulated lensless speckle imaging, which introduces oscillatory motion to the magnetic-bead-conjugated rare cells of interest through a periodic magnetic force and uses lensless time-resolved holographic speckle imaging to rapidly detect the target cells in three dimensions (3D). In addition to using cell-specific antibodies to magnetically label target cells, detection specificity is further enhanced through a deep-learning-based classifier that is based on a densely connected pseudo-3D convolutional neural network (P3D CNN), which automatically detects rare cells of interest based on their spatio-temporal features under a controlled magnetic force. To demonstrate the performance of this technique, we built a high-throughput, compact and cost-effective prototype for detecting MCF7 cancer cells spiked in whole blood samples. Through serial dilution experiments, we quantified the limit of detection (LoD) as 10 cells per millilitre of whole blood, which could be further improved through multiplexing parallel imaging channels within the same instrument. This compact, cost-effective and high-throughput computational cytometer can potentially be used for rare cell detection and quantification in bodily fluids for a variety of biomedical applications
Impact of Enquiry Based Learning (EBL) on student midwife praxis.
Midwifery training in Ireland moved to Higher Education in 2006. This shift established a physical and educational separation of theory and practice. The adoption of Enquiry Based Learning (EBL) by one Irish midwifery education institution attempted to address this division. Enquiry Based Learning (EBL) has the potential to develop student reflexivity and evidence assimilation across the career-span and may therefore enhance student praxis. EBL has been championed as an example of an educational model that supports praxis, helping to create competent practitioners through the use of authentic learning scenarios that address the theory practice divide. The current research study represents the first formal evaluation of EBL in undergraduate midwifery education in the South of Ireland. The study was a mixed-methods design that utilised focus groups, interviews and survey to ascertain the opinions of first exposure to EBL amongst a cohort of first year student midwives. Findings demonstrate the value of EBL in enhancing student midwife praxis
Galaxy clustering in the NEWFIRM Medium Band Survey: the relationship between stellar mass and dark matter halo mass at 1 < z < 2
We present an analysis of the clustering of galaxies as a function of their
stellar mass at 1 < z < 2 using data from the NEWFIRM Medium Band Survey
(NMBS). The precise photometric redshifts and stellar masses that the NMBS
produces allows us to define a series of mass limited samples of galaxies more
massive than 0.7, 1 and 3x10^10 Msun in redshift intervals centered on z = 1.1,
1.5 and 1.9 respectively. In each redshift interval we show that there exists a
strong dependence of clustering strength on the stellar mass limit of the
sample, with more massive galaxies showing a higher clustering amplitude on all
scales. We further interpret our clustering measurements in the LCDM
cosmological context using the halo model of galaxy clustering. We show that
the typical halo mass of central and satellite galaxies increases with stellar
mass, whereas the satellite fraction decreases with stellar mass, qualitatively
the same as is seen at z < 1. We see little evidence of any redshift dependence
in the stellar mass-to-halo mass relationship over our narrow redshift range.
However, when we compare with similar measurements at z~0, we see clear
evidence for a change in this relation. If we assume a universal baryon
fraction, the ratio of stellar mass to halo mass reveals the fraction of
baryons that have been converted to stars. We see that the peak in this star
formation efficiency for central galaxies shifts to higher halo masses at
higher redshift, moving from ~7x10^11 Msun at z~0 to ~3x10^12 Msun at z~1.5,
revealing evidence of `halo downsizing'. Finally we show that for highly biased
galaxy populations at z > 1 there may be a discrepancy between the measured
space density and clustering and that predicted by the halo model. This could
imply that there is a problem with one or more ingredients of the halo model at
these redshifts, for instance the halo bias relation or the halo profile.Comment: Accepted for publication in ApJ. Correction made to typo in halo
masses in conclusion
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