2,087 research outputs found

    Epilithic diatoms (Bacillariophyta) from cloud forest and alpine streams in Bolivia, South America II: A preliminary report on the diatoms from Sorata, Department of La Paz

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    Un total de siete muestras de epiHton fueron colectadas en rios dentro de ungradiente altitudinal en el bosque nublado de Bokvia, cerca de la capital La Paz. Laflora diatomologica es diversa v no se encontraron patrones altitudinales claros. Talflora esta compuesta por especies cosmopolitas y taxa restringidos a los Andes con losgeneros Gompbonema, Nit^schia, Engonopsis v Engonema agrupando al mayor numero deespecies e individuos con mayores frecuencias. La flora esta tambien representada porvarios taxa alcalifilos y alcaKbiontes, reflejando los altos valores de pH de los rios. Las caracteristicas de los sitios muestreados, asi como una lista de taxa y figurasrepresentativas se presentan en este trabajo

    Low-Mass Eclipsing Binaries in the Initial Kepler Data Release

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    We identify 231 objects in the newly released Cycle 0 dataset from the Kepler Mission as double-eclipse, detached eclipsing binary systems with Teff < 5500 K and orbital periods shorter than ~32 days. We model each light curve using the JKTEBOP code with a genetic algorithm to obtain precise values for each system. We identify 95 new systems with both components below 1.0 M_sun and eclipses of at least 0.1 magnitudes, suitable for ground-based follow-up. Of these, 14 have periods less than 1.0 day, 52 have periods between 1.0 and 10.0 days, and 29 have periods greater than 10.0 days. This new sample of main-sequence, low-mass, double-eclipse, detached eclipsing binary candidates more than doubles the number of previously known systems, and extends the sample into the completely heretofore unexplored P > 10.0 day period regime. We find preliminary evidence from these systems that the radii of low-mass stars in binary systems decrease with period. This supports the theory that binary spin-up is the primary cause of inflated radii in low-mass binary systems, although a full analysis of each system with radial-velocity and multi-color light curves is needed to fully explore this hypothesis. As well, we present 7 new transiting planet candidates that do not appear among the recently released list of 706 candidates by the Kepler team, nor in the Kepler False Positive Catalog, along with several other new and interesting systems. We also present novel techniques for the identification, period analysis, and modeling of eclipsing binaries.Comment: 22 pages in emulateapj format. 9 figures, 4 tables, 2 appendices. Accepted to AJ. Includes a significant addition of new material since last arXiv submission and an updated method for estimating masses and radi

    DNA Torsional Solitons in Presence of localized Inhomogeneities

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    In the present paper we investigate the influence of inhomogeneities in the dynamics and stability of DNA open states, modeled as propagating solitons in the spirit of a Generalized Yakushevish Model. It is a direct consecuence of our model that there exists a critical distance between the soliton's center of mass and the inhomogeneity at which the interaction between them can change the stability of the open state.Furtherly from this results was derived a renormalized potential funtion.Comment: RevTex, 13 pages, 3 figures, final versio

    Bilateral Internuclear Ophthalmoplegia in a Patient with Devic's Neuromyelitis Optica

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    An unusual presentation of Devic's neuromyelitis optica (NMO) disease associated with bilateral internuclear ophthalmoplegia (INO) is described. A 32-year-old pregnant patient was diagnosed with NMO. First symptoms were headache and sudden visual loss in her right eye (RE). Eighteen months ago, she reported other neurologic symptoms such as paresthesia. Based on her visual field, fundoscopy and Ishihara test, she was diagnosed with retrobulbar neuritis of the RE. After delivery, new neurologic symptoms resembling transverse myelitis appeared. She was treated with methylprednisolone and plasmapheresis, which improved her visual acuity; however, a sudden bilateral INO appeared, with adduction defect and nystagmus with abduction in both eyes. No improvement was obtained after treatment with azathioprine and rituximab. Paresis of the legs and the right arm persisted, but double vision and OIN gradually disappeared. At the end, the patient had a residual exophoria in the RE and nystagmus with abduction in the left eye. Prevalence of NMO is lower than one case per one million inhabitants, and it is not likely to affect the encephalic trunk; furthermore, bilateral INO in NMO is rare. Two major criteria and at least two of the three minor ones are required to confirm a NMO diagnosis, and our patient fulfilled these diagnosis criteria

    Cervical cancer, human papillomavirus (HPV), and HPV vaccination: Exploring gendered perspectives, knowledge, attitudes, and cultural taboos among Mexican American adults

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    Background: Gendered perspectives may be particularly important in shaping norms and values around HPV and HPV vaccination, as previous research suggests that sexuality taboos (e.g. promiscuity) may contribute to low perceived risk among adolescent and young adult Hispanic females. However, research to date focuses primarily on Hispanic mothers, adolescent females, and women of HPV vaccine-eligible age. Hispanic father\u27s perspectives are relatively unknown despite father\u27s important role in shaping norms for their female children. Objective: To close this gap, this study examines gendered perspectives in knowledge, beliefs, and attitudes about HPV and HPV vaccination from Hispanic parents (mothers and fathers), women of vaccine-eligible age (18-26 years old), and women eligible for Pap Test screening (\u3e26 years old) living in two counties along the Texas-Mexico border. Design: We conducted eight focus groups. Research staff transcribed audio recordings verbatim and uploaded them into Atlas(ti) 5.0 for analysis. The research team analyzed the data for content, meaning, patterns and themes using the constant comparison approach. Results: Perspectives were highly gendered. Women\u27s (all groups combined) beliefs focused on misconceptions around how the HPV virus is contracted (e.g. toilet surfaces). Women also linked HPV-related sexual risk to adultery and indiscretion of male partners. Fathers (men) were more likely to link risk to female promiscuity. Fathers also worried that HPV vaccination might increase promiscuity. All groups believe that HPV vaccination is a way to protect Hispanic females in the face of beliefs around sexual behavior and risk of contracting HPV. Conclusion: Results suggest gendered differences in risk beliefs concerning HPV among Hispanics living along the Texas-Mexico border. Researchers can use these findings to address barriers to HPV vaccination, as well as to create culturally appropriate prevention messages that may help reduce disparities in HPV among Hispanic women

    Association of single nucleotide polymorphisms in Pre-miR-27a, Pre-miR-196a2, Pre-miR-423, miR-608 and Pre-miR-618 with breast cancer susceptibility in a South American population

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    Indexación: Web of ScienceBackground MicroRNAs (miRNAs) are a novel class of endogenous, non-coding, single-stranded RNAs capable of regulating gene expression by suppressing translation or degrading mRNAs. Single nucleotide polymorphisms (SNP) can alter miRNA expression, resulting in diverse functional consequences. Previous studies have examined the association of miRNA SNPs with breast cancer (BC) susceptibility. The contribution of miRNA gene variants to BC susceptibility in South American women had been unexplored. Our study evaluated the association of the SNPs rs895819 in pre-miR27a, rs11614913 in pre-miR-196a2, rs6505162 in pre-miR-423, rs4919510 in miR-608, and rs2682818 in pre-mir-618 with familial BC and early-onset non-familial BC in non-carriers of BRCA1/2 mutations from a South American population. Results We evaluated the association of five SNPs with BC risk in 440 cases and 807 controls. Our data do not support an association of rs11614913:C > T and rs4919510:C > G with BC risk. The rs6505162:C > A was significantly associated with increased risk of familial BC in persons with a strong family history of BC (OR = 1.7 [95 % CI 1.0–2.0] p = 0.05). The rs2682818:C > A genotype C/A is associated with an increased BC risk in non-familial early-onset BC. For the rs895819:A > G polymorphism, the genotype G/G is significantly associated with reduced BC risk in families with a moderate history of BC (OR = 0.3 [95 % CI 0.1–0.8] p = 0.01). Conclusions The contribution of variant miRNA genes to BC in South American women had been unexplored. Our findings support the following conclusions: a) rs6505162:C > A in pre-miR-423 increases risk of familial BC in families with a strong history of BC; b) the C/A genotype at rs2682818:C > A (pre-miR-618) increases BC risk in non-familial early-onset BC; and c) the G/G genotype at rs895819:A > G (miR-27a) reduces BC risk in families with a moderate history of BC.http://bmcgenet.biomedcentral.com/articles/10.1186/s12863-016-0415-

    A Test of Pre-Main-Sequence Lithium Depletion Models

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    Despite the extensive study of lithium depletion during pre-main-sequence contraction, studies of individual stars show discrepancies between ages determined from the HR diagram and ages determined from lithium depletion (Song et al. 2002, White & Hillenbrand 2005) indicating open questions in the pre-main-sequence evolutionary models. To further test these models, we present high resolution spectra for members of the Beta Pictoris Moving Group (BPMG), which is young and nearby. We measure equivalent widths of the 6707.8 Angstrom Li I line in these stars and use them to determine lithium abundances. We combine the lithium abundance with the predictions of pre-main-sequence evolutionary models in order to calculate a lithium depletion age for each star. We compare this age to the age predicted by the HR diagram of the same model. We find that the evolutionary models under-predict the amount of lithium depletion for the BPMG given its nominal HR diagram age of ~12 Myr (Zuckerman et al. 2001), particularly for the mid-M stars, which have no observable Li I line. This results in systematically older ages calculated from lithium depletion isochrones than from the HR diagram. We suggest that this discrepancy may be related to the discrepancy between measured M-dwarf radii and the smaller radii predicted by evolutionary models.Comment: Accepted by ApJ; 21 pages, 5 figure

    The JAK3Q988P mutation reveals oncogenic potential and resistance to ruxolitinib

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    T-cell acute lymphoblastic leukemia (T-ALL) arises from the malignant transformation of T-cell progenitors at various differentiation stages. Given that patients who relapse have a dismal prognosis, there is an urgent need to identify the molecular alterations that are present in such patients and promote leukemogenesis to implement personalized therapies with higher efficacy and fewer adverse effects. In the present manuscript, we identified the JAK3Q988P mutation in a T-ALL patient who did not achieve a durable response after the conventional treatment and whose tumor cells at relapse presented constitutive activation of the JAK/STAT pathway. Although JAK3Q988P has been previously identified in T-ALL patients from different studies, the functional consequences exerted by this mutation remain unexplored. Through the combination of different hematopoietic cellular models, we functionally characterize JAK3Q988P as an oncogenic mutation that contributes to leukemogenesis. Notably, JAK3Q988P not only promotes constitutive activation of the JAK/STAT pathway in the absence of cytokines and growth factors, as is the case for other JAK3 mutations that have been functionally characterized as oncogenic, but also functions independently of JAK1 and IL2RG, resulting in high oncogenic potential as well as resistance to ruxolitinib. Our results indicate that ruxolitinib may not be efficient for future patients bearing the JAK3Q988P mutation who instead may obtain greater benefits from treatments involving other pharmacological inhibitors such as tofacitinib.This work was supported in part by funds from Ministerio de Economía y Competitividad (SAF2015‐70561‐R; MINECO/FEDER, EU to J.F.‐P. and M.V.‐M.); Ministerio de Ciencia, Innovación y Universidades (RTI2018‐093330‐B‐I00; MCIU/FEDER, EU to J.F.‐P. and J.S.); Fundación Ramón Areces (CIVP19S7917 to J.F.‐P.); Comunidad de Madrid (B2017/BMD‐3778; LINFOMAS‐CM to J.F.‐P.); Asociación Española Contra el Cáncer (AECC, 2018; PROYE18054PIRI to J.F.‐P.);and Instituto de Investigación Sanitaria Fundación Jiménez Díaz to J.F.‐P.;institutional grants from the Fundación Ramón Areces and Banco de Santander to the CBMSO are also acknowledged.S

    GOLVEN peptide signalling through RGI receptors and MPK6 restricts asymmetric cell division during lateral root initiation

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    During lateral root initiation, lateral root founder cells undergo asymmetric cell divisions that generate daughter cells with different sizes and fates, a prerequisite for correct primordium organogenesis. An excess of the GLV6/RGF8 peptide disrupts these initial asymmetric cell divisions, resulting in more symmetric divisions and the failure to achieve lateral root organogenesis. Here, we show that loss-of-function GLV6 and its homologue GLV10 increase asymmetric cell divisions during lateral root initiation, and we identified three members of the RGF1 INSENSITIVE/RGF1 receptor subfamily as likely GLV receptors in this process. Through a suppressor screen, we found that MITOGEN-ACTIVATED PROTEIN KINASE6 is a downstream regulator of the GLV pathway. Our data indicate that GLV6 and GLV10 act as inhibitors of asymmetric cell divisions and signal through RGF1 INSENSITIVE receptors and MITOGEN-ACTIVATED PROTEIN KINASE6 to restrict the number of initial asymmetric cell divisions that take place during lateral root initiation. The authors demonstrate the negative role of GOLVEN peptides during lateral root initiation in Arabidopsis, at the very early stage of the first asymmetric cell division of lateral root founder cells, and identify the receptors for these peptides
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