1,842 research outputs found
The Herschel Planetary Nebula Survey (HerPlaNS) - a comprehensive dusty photoionization model of NGC6781
We perform a comprehensive analysis of the planetary nebula (PN) NGC6781 to
investigate the physical conditions of each of its ionized, atomic, and
molecular gas and dust components and the object's evolution, based on
panchromatic observational data ranging from UV to radio. Empirical nebular
elemental abundances, compared with theoretical predictions via nucleosynthesis
models of asymptotic giant branch (AGB) stars, indicate that the progenitor is
a solar-metallicity, 2.25-3.0 Msun initial-mass star. We derive the best-fit
distance of 0.46 kpc by fitting the stellar luminosity (as a function of the
distance and effective temperature of the central star) with the adopted
post-AGB evolutionary tracks. Our excitation energy diagram analysis indicate
high excitation temperatures in the photodissociation region (PDR) beyond the
ionized part of the nebula, suggesting extra heating by shock interactions
between the slow AGB wind and the fast PN wind. Through iterative fitting using
the Cloudy code with empirically-derived constraints, we find the best-fit
dusty photoionization model of the object that would inclusively reproduce all
of the adopted panchromatic observational data. The estimated total gas mass
(0.41 Msun) corresponds to the mass ejected during the last AGB thermal pulse
event predicted for a 2.5 Msun initial-mass star. A significant fraction of the
total mass (about 70 percent) is found to exist in the PDR, demonstrating the
critical importance of the PDR in PNe that are generally recognized as the
hallmark of ionized/H+ regions.Comment: 34 pages, 13 Figures and 16 Tables, accepted for publication in the
Astrophysical Journal Supplement Serie
Análisis de encontrar un mercado objetivo para el negocio de producción y venta de galletas de tarwi para contribuir con la mejora en la alimentación de los niños en Lima
El presente trabajo de investigación es un Plan de Negocio que tiene como objetivo la producción de galletas de tarwi, dirigido a niños entre los 5 y 9 años de Lima Metropolitana, que tengan problemas de anemia. En ese sentido, la finalidad del plan es contribuir a la reducción de esta enfermedad en los referidos niños.
Dado el crecimiento que se viene presentando en el mercado de personas de conducta saludable, estas galletas buscan atender dicho nicho, para lo cual se utilizará el canal indirecto de distribución, distribuyéndose en supermercados, bodegas y mercados distritales, a fin de ser aceptado como un alimento natural, funcional y de calidad que aporte al bienestar de los potenciales consumidores.
Considerando la parte legal, se ha considerado que la empresa será una sociedad anónima cerrada (S.A.C.) y, estará conformada por dos accionistas.
Para el levantamiento de información, en el marco de una investigación aplicada, de enfoque cuantitativo, de nivel descriptivo y de diseño no experimental, se ha considerado una población de 54 531 entre niñas y niños domiciliados en los distritos de Comas y La Victoria, tomándose como muestra a 73 niños y 71 bodegas de los referidos distritos
Conservation of the PBL-RBOH immune module in land plants
The rapid production of reactive oxygen species (ROS) is a key signaling output in plant immunity. In the angiosperm model species Arabidopsis thaliana (hereafter Arabidopsis), recognition of non- or altered-self elicitor patterns by cell-surface immune receptors activates the receptor-like cytoplasmic kinases (RLCKs) of the AVRPPHB SUSCEPTIBLE 1 (PBS1)-like (PBL) family, particularly BOTRYTIS-INDUCED KINASE1 (BIK1). BIK1/PBLs in turn phosphorylate the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase RESPIRATORY BURST OXIDASE HOMOLOG D (RBOHD) to induce apoplastic ROS production. PBL and RBOH functions in plant immunity have been extensively characterized in flowering plants. Much less is known about the conservation of pattern-triggered ROS signaling pathways in non-flowering plants. In this study, we show that in the liverwort Marchantia polymorpha (hereafter Marchantia), single members of the RBOH and PBL families, namely MpRBOH1 and MpPBLa, are required for chitin-induced ROS production. MpPBLa directly interacts with and phosphorylates MpRBOH1 at specific, conserved sites within its cytosolic N terminus, and this phosphorylation is essential for chitin-induced MpRBOH1-mediated ROS production. Collectively, our work reveals the functional conservation of the PBL-RBOH module that controls pattern-triggered ROS production in land plants
Relación entre violencia familiar y estilos de afrontamiento en adolescentes de una institución educativa de la región Piura, 2021
El presente estudio pretendió investigar la relación entre violencia familiar y los
estilos de afrontamiento en adolescentes de una institución educativa de la región
de Piura, 2021. Este tratado cuenta con una naturaleza cuantitativa, con un diseño
no experimental – transaccional y de tipo descriptivo correlacional. Para la
realización de la investigación se tuvo una población finita conformada por 176
estudiantes pertenecientes al 4to año de educación secundaria del Colegio
Emblemático Carlos Augusto Salaverry de Sullana – Piura, del mismo modo se
tomó como muestra representativa a 121 adolescentes pertenecientes a la
institución educativa antes mencionada. Así mismo se hizo uso de dos
cuestionarios con el fin de evaluar las variables a estudiar, estos serán el
Cuestionario de Violencia Familiar [VIFA], creado originalmente por Altamirano y
Castro (2013); y la Escala de Afrontamiento para Adolescentes, creado por
Fredenberg y Lewis (1993) en Australia. Mediante el análisis estadístico a través
del programa SPSS 25 se llegó a la conclusión de que no existe relación entre la
violencia familiar y los estilos de afrontamiento; del mismo modo se observa la no
existente relación entre las dimensiones de la violencia familiar y los estilos de
afrontamiento (p<0.05)
Efecto del gel del extracto liofilizado de Croton lechleri sobre el tejido pulpar en pulpotomías realizadas en Oryctolagus cuniculus
Objective. To determine the effect of the Croton lechleri lyophilized extract gel on root pulp tissue of pulpotomies performed on Oryctolagus cuniculus. Methods. Thirty-two two-month-old male New Zealand rabbits race, were randomly assigned into four experimental groups: a) control, b) formocresol, c) 1% Croton lechleri and d) 2.5% Croton lechleri. Four pulpotomies were done on each animal. Clinical variables (abscesses, tooth mobility and infections) and histopathological variables (fiber formation, pro-inflammatory cell and regenerative cell number) were analyzed after 1,7,15, and 30 days. Results. No clinical signs were evident in all experimental groups evaluation at any time period. In the first day histopathological evaluation, there were abundant presence of capillaries in all control group samples and half of formocresol ones, while 1% Croton lechleri and 2.5% Croton lechleri groups, had a moderate number in all samples. In the 7,15 and 30 evaluation days, the number of capillaries was higher in formocresol group than the others. The 2.5% Croton lechleri group, showed a lower number of inflammatory cells (macrophages and lymphocytes), a higher number of repair cells (fibroblasts, odontoblasts) and normal collagen fibers than the others, over all evaluated times. Conclusions. The 2.5% Croton lechleri lyophilized extract gel showed a greater anti-inflammatory, healing and regenerating effect on the pulp tissue compared to the other experimental groups.Objetivo. Determinar el efecto del gel del extracto liofilizado de Croton lechleri sobre el tejido pulpar radicular en pulpotomías realizadas en Oryctolagus cuniculus. Métodos. Se utilizaron 32 conejos machos de raza neozelandesa de dos meses de edad que se asignaron aleatoriamente en cuatro grupos de ocho animales: control, formocresol, Croton lechleri 1% y Croton lechleri 2,5%. En cada animal se trabajaron cuatro pulpotomías. Se analizaron variables clínicas (presencia de abscesos, movilidad dentaria e infecciones) e histopatológicas (formación de fibras, cantidad de células proinflamatorias y cantidad de células regenerativas) al cabo de un día, 7, 15, y 30 días. Resultados. En la evaluación clínica, en todos los tiempos evaluados, no se evidenció la existencia de abscesos submucosos, fistula o movilidad dentaria en ninguno de los grupos de tratamiento. En la evaluación histopatológica a 1 día, la presencia de capilares fue abundante en todas las muestras del grupo control y en la mitad de las muestras del grupo formocresol, mientras fue moderada en todas las muestras de los grupos Croton lechleri 1% y 2,5%. A los 7, 15 y 30 días, la presencia de capilares fue mayor en el grupo formocresol. En todos los tiempos evaluados en el grupo Croton lechleri 2,5%, evidenció menor número de células inflamatorias (macrófagos y linfocitos), mayor cantidad de células de reparación (fibroblastos, odontoblastos) y fibras colágenas normales. Conclusiones. El gel del extracto liofilizado de Croton lechleri 2,5% evidenció mayor efecto antiinflamatorio, cicatrizante y regenerador sobre el tejido pulpar en comparación a los otros tratamientos
Conservation of the PBL-RBOH immune module in land plants
The rapid production of reactive oxygen species (ROS) is a key signaling output in plant immunity. In the angiosperm model species Arabidopsis thaliana (hereafter Arabidopsis), recognition of non- or altered-self elicitor patterns by cell-surface immune receptors activates the receptor-like cytoplasmic kinases (RLCKs) of the AVRPPHB SUSCEPTIBLE 1 (PBS1)-like (PBL) family, particularly BOTRYTIS-INDUCED KINASE1 (BIK1).1,2,3 BIK1/PBLs in turn phosphorylate the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase RESPIRATORY BURST OXIDASE HOMOLOG D (RBOHD) to induce apoplastic ROS production.4,5 PBL and RBOH functions in plant immunity have been extensively characterized in flowering plants. Much less is known about the conservation of pattern-triggered ROS signaling pathways in non-flowering plants. In this study, we show that in the liverwort Marchantia polymorpha (hereafter Marchantia), single members of the RBOH and PBL families, namely MpRBOH1 and MpPBLa, are required for chitin-induced ROS production. MpPBLa directly interacts with and phosphorylates MpRBOH1 at specific, conserved sites within its cytosolic N terminus, and this phosphorylation is essential for chitin-induced MpRBOH1-mediated ROS production. Collectively, our work reveals the functional conservation of the PBL-RBOH module that controls pattern-triggered ROS production in land plants
Cross-species genomic and functional analyses identify a combination therapy using a CHK1 inhibitor and a ribonucleotide reductase inhibitor to treat triple-negative breast cancer
INTRODUCTION: Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is diagnosed in approximately 15% of all human breast cancer (BrCa) patients. Currently, no targeted therapies exist for this subtype of BrCa and prognosis remains poor. Our laboratory has previously identified a proliferation/DNA repair/cell cycle gene signature (Tag signature) that is characteristic of human TNBC. We hypothesize that targeting the dysregulated biological networks in the Tag gene signature will lead to the identification of improved combination therapies for TNBC. METHODS: Cross-species genomic analysis was used to identify human breast cancer cell lines that express the Tag signature. Knock-down of the up-regulated genes in the Tag signature by siRNA identified several genes that are critical for TNBC cell growth. Small molecule inhibitors to two of these genes were analyzed, alone and in combination, for their effects on cell proliferation, cell cycle, and apoptosis in vitro and tumor growth in vivo. Synergy between the two drugs was analyzed by the Chou-Talalay method. RESULTS: A custom siRNA screen was used to identify targets within the Tag signature that are critical for growth of TNBC cells. Ribonucleotide reductase 1 and 2 (RRM1 and 2) and checkpoint kinase 1 (CHK1) were found to be critical targets for TNBC cell survival. Combination therapy, to simultaneously attenuate cell cycle checkpoint control through inhibition of CHK1 while inducing DNA damage with gemcitabine, improved therapeutic efficacy in vitro and in xenograft models of TNBC. CONCLUSIONS: This combination therapy may have translational value for patients with TNBC and improve therapeutic response for this aggressive form of breast cancer
The circumstellar material around SN IIn 1997eg: Another detection of Very Narrow P Cygni profile
We report the detection of a very narrow P Cygni profile on top of the broad
emission Ha and Hb lines of the Type IIn Supernova 1997eg. A similar feature
has been detected in SN 1997ab (Salamanca et al. 1998), SN 1998S (Meikle &
Geballe 1998, Fassia et al. 2001) and SN 1995G (Filippenko & Schlegel 1995).
The detection of the narrow P Cygni profile indicates the existence of a dense
circumstellar material (CSM) into which the ejecta of the supernova is
expanding. From the analysis of the spectra of SN 1997eg we deduce (a) that
such CSM is very dense (n ~ 5x10^7 cm^-3), (b) that has a low expanding
velocity of about 160 \kms. The origin of such dense CSM can be either a very
dense progenitor wind (dotM ~ 10^-2 solar masses per year) or a circumstellar
shell product of the progenitor wind expanding into a high pressure
environment.Comment: Accepted for publication in MNRA
Integrated genome-wide genotyping and gene expression profiling reveals BCL11B as a putative oncogene in acute myeloid leukemia with 14q32 aberrations
Acute myeloid leukemia is a neoplasm characterized by recurrent molecular aberrations traditionally demonstrated by cytogenetic analyses. We used high density genome-wide genotyping and gene expression profiling to reveal acquired cryptic abnormalities in acute myeloid leukemia. By genome-wide genotyping of 137 cases of primary acute myeloid leukemia, we disclosed a recurrent focal amplification on chromosome 14q32, which included the genes BCL11B, CCNK, C14orf177 and SETD3, in two cases. In the affected cases, the BCL11B gene showed consistently high mRNA expression, whereas the expression of the other genes was unperturbed. Flu
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