979 research outputs found
Evaluación técnica y económica para el mejoramiento de suelos finos con fines de cimentación, por medio de compactación dinámica e inclusiones rígidas
El presente trabajo de tesis tuvo como finalidad evaluar de manera técnica y económica los mejoramientos de suelos finos a través de los métodos de compactación dinámica e inclusiones rígidas. Estas técnicas mejoran de manera significativa las propiedades geotécnicas de los suelos en su estado natural, como es la capacidad portante, reducir su nivel de asentamiento y evitar el fenómeno de licuación.
La Compactación Dinámica (C.D.) es una técnica desarrollada en Europa y que se está aplicando en Sudamérica con buenos resultados, consiste en aplicar impactos continuos de una masa a cierta altura, que comprime el suelo con una determinada energía de impacto, logrando mejorar las propiedades mecánicas del suelo.
Detallaremos un caso práctico de C.D. realizado en el Perú y como fue el proceso de mejoramiento de suelo. Se analizaron las características antes durante y después, a través de ensayos de campo y de laboratorio, bajo el soporte de la normativa técnica vigente (N.T.E. 050), estos suelos al ser finos y colapsables presentaron una capacidad portante inicial de 0.80 Kg/cm2, con esta técnica evaluaremos como se logró mejorar dicho valor y reducir el asentamiento de manera significativa.
De las inclusiones rígidas se efectúa un modelo teórico para evaluar las propiedades del suelo del caso práctico.
Con los resultados obtenidos en ambos casos, se ha procedido a evaluar y comparar de manera técnica, considerando el tiempo y el costo, con la finalidad de obtener conclusiones y recomendaciones que ratifiquen los objetivos del presente trabajo.Tesi
Molecules as tracers of galaxy evolution: an EMIR survey. I. Presentation of the data and first results
We investigate the molecular gas properties of a sample of 23 galaxies in
order to find and test chemical signatures of galaxy evolution and to compare
them to IR evolutionary tracers. Observation at 3 mm wavelengths were obtained
with the EMIR broadband receiver, mounted on the IRAM 30 m telescope on Pico
Veleta, Spain. We compare the emission of the main molecular species with
existing models of chemical evolution by means of line intensity ratios
diagrams and principal component analysis. We detect molecular emission in 19
galaxies in two 8 GHz-wide bands centred at 88 and 112 GHz. The main detected
transitions are the J=1-0 lines of CO, 13CO, HCN, HNC, HCO+, CN, and C2H. We
also detect HC3N J=10-9 in the galaxies IRAS 17208, IC 860, NGC 4418, NGC 7771,
and NGC 1068. The only HC3N detections are in objects with HCO+/HCN<1 and warm
IRAS colours. Galaxies with the highest HC3N/HCN ratios have warm IRAS colours
(60/100 {\mu}m>0.8). The brightest HC3N emission is found in IC 860, where we
also detect the molecule in its vibrationally excited state.We find low HNC/HCN
line ratios (<0.5), that cannot be explained by existing PDR or XDR chemical
models. Bright HC3N emission in HCO+-faint objects may imply that these are not
dominated by X-ray chemistry. Thus the HCN/HCO+ line ratio is not, by itself, a
reliable tracer of XDRs. Bright HC3N and faint HCO+ could be signatures of
embedded starformation, instead of AGN activity
Use of aequorin-based indicators for monitoring Ca2+ in acidic organelles
Producción CientíficaOver the last years, there is accumulating evidence that acidic organelles can accumulate and release Ca2+ upon cell activation. Hence, reliable recording of Ca2+ dynamics in these compartments is essential for understanding the physiopathological aspects of acidic organelles. Genetically encoded Ca2+ indicators (GECIs) are valuable tools to monitor Ca2+ in specific locations, although their use in acidic compartments is challenging due to the pH sensitivity of most available fluorescent GECIs. By contrast, bioluminescent GECIs have a combination of features (marginal pH sensitivity, low background, no phototoxicity, no photobleaching, high dynamic range and tunable affinity) that render them advantageous to achieve an enhanced signal-to-noise ratio in acidic compartments. This article reviews the use of bioluminescent aequorin-based GECIs targeted to acidic compartments. A need for more measurements in highly acidic compartments is identified.Ministerio de Ciencia e Innovación (PID2020-116086RB-I00 )Junta de Castilla y León (Ref. CLU- 2019-02)Biotechnology and Biological Sciences Research Council, Reino Unido (BB/T015853/1 y BB/W01551X/1
Mapping photodissociation and shocks in the vicinity of Sgr A*
We have obtained maps of the molecular emission within the central five
arcminutes (12 pc) of the Galactic center (GC) in selected molecular tracers:
SiO(2-1), HNCO(5_{0,5}-4_{0,4}), and the J=1-->0 transition of H^{13}CO+,
HN^{13}C, and C^{18}O at an angular resolution of 30" (1.2 pc). The mapped
region includes the circumnuclear disk (CND) and the two surrounding giant
molecular clouds (GMCs) of the Sgr A complex, known as the 20 and 50 km s^{-1}
molecular clouds.Additionally, we simultaneously observed the J=2-1 and 3-2
transitions of SiO toward selected positions to estimate the physical
conditions of the molecular gas. The SiO(2-1) and H^{13}CO+(1-0) emission
covers the same velocity range and presents a similar distribution. In
contrast, HNCO(5-4) emission appears in a narrow velocity range mostly
concentrated in the 20 and 50 km s^{-1} GMCs. The HNCO column densities and
fractional abundances present the highest contrast, with difference factors of
60 and 28, respectively. Their highest values are found toward the cores
of the GMCs, whereas the lowest ones are measured at the CND. SiO abundances do
not follow this trend, with high values found toward the CND, as well as the
GMCs. By comparing our abundances with those of prototypical Galactic sources
we conclude that HNCO, similar to SiO, is ejected from grain mantles into
gas-phase by nondissociative C-shocks. This results in the high abundances
measured toward the CND and the GMCs. However, the strong UV radiation from the
Central cluster utterly photodissociates HNCO as we get closer to the center,
whereas SiO seems to be more resistant against UV-photons or it is produced
more efficiently by the strong shocks in the CND. Finally, we discuss the
possible connections between the molecular gas at the CND and the GMCs using
the HNCO/SiO, SiO/CS, and HNCO/CS intensity ratios as probes of distance to the
Central cluster.Comment: 26 pages plus 2 appendixes with additional figures. 17 figures in
total. Accepted for publication in A&
Teknik Tekstil Endüstrileri: Nonwoven Kumaş Örneği Ve Gaziantep’in Durumu
"Teknik tekstiller" kavramı ilk ortaya çıktığında sadece endüstriyel amaçlı (giysi ve ev tekstili dışında) tekstil malzemeleri için kullanılan bir ifade iken şu an geniş bir sektörü temsil eden bir kavrama dönüşmüştür. 130 milyar $'lık bir piyasa ve yüksek bir katma değer ile birçok ülke ve yatırımcının tercih ettiği bir sektör haline gelmiştir. Yıllar geçtikçe, teknolojinin de gelişimiyle, teknik tekstil üretiminde ve uygulama alanlarında büyük çapta artma olmuş; çok farklı özelliklere sahip lifler üretilmeye başlanmıştır. Teknik tekstiller, önceleri askeri ve sportif giysilerde kullanılmış; sonraları moda tasarımcılarının bu malzemeleri koleksiyonlarına taşımalarıyla, yüksek teknolojik tekstiller, günlük giysilere de adapte edilmeye başlanmıştır. 90'lı yıllardan sonra elektronik ürünlerin giysilerimize entegre edilmesiyle birlikte teknik tekstil üretimi yeni bir boyut kazanmıştır. Endüstriyel tekstil malzemesi üreticileri, moda tasarımcıları, tekstil sanatçıları ve bilim adamlarına kadar alanında uzman birçok kişinin katılımıyla teknik/akıllı malzemeler alanında yeni ürünler ortaya konmaktadır. Bu çalışmada, teknik tekstil piyasasının genişliği ve üretim açısından önde yer alan ülkelerdeki durumunun ne aşamada olduğu, gelecekte piyasanın ulaşacağı seviye ve ülkemizdeki durum hakkında veriler bir araya getirilerek sektörün genel bir bakış açısı ile değerlendirme imkânı sunmaya çalışılmıştır. İlk olarak teknik tekstil kavramları açıklanmış, daha sonra teknik tekstil sınıflamaları üzerinde durulmuştur. Dünya genelinde trend bir sektör haline gelen bu alanda genel durum ve ülkemizin durumu ortaya konmaya çalışılmış, iktisadi açıdan piyasa yapısı analiz edilmeye çalışılmış, yoğunlaşma ve Herfindal ve Hirschman endeksleri uygulanarak sektör yapısı hakkında daha net veriler ortaya konmuştur. Gaziantep'teki firmalar üzerinde yapılan bu endüstri yapısı değerlendirmesinden sonra firmaların mevcut durumlarını değerlendirmek için Swot analizi yapılmıştır
Arsenate and arsenite differential toxicity in Tetrahymena thermophila
A comparative analysis of toxicities of both arsenic forms (arsenite and arsenate) in the model eukaryotic microorganism Tetrahymena thermophila (ciliate protozoa) has shown the presence of various detoxification mechanisms and cellular effects comparable to those of animal cells under arsenic stress. In the wild type strain SB1969 arsenate is almost 2.5 times more toxic than arsenite. According to the concentration addition model used in binary metallic mixtures their toxicities show an additive effect. Using fluorescent assays and flow cytometry, it has been detected that As(V) generates elevated levels of ROS/RNS compared to As(III). Both produce the same levels of superoxide anion, but As(V) also causes greater increases in hydrogen peroxide and peroxynitrite. The mitochondrial membrane potential is affected by both As(V) and As(III), and electron microscopy has also revealed that mitochondria are the main target of both arsenic ionic forms. Fusion/fission and swelling mitochondrial and mitophagy, together with macroautophagy, vacuolization and mucocyst extruction are mainly associated to As(V) toxicity, while As(III) induces an extensive lipid metabolism dysfunction (adipotropic effect). Quantitative RT-PCR analysis of some genes encoding antioxidant proteins or enzymes has shown that glutathione and thioredoxin metabolisms are involved in the response to arsenic stress. Likewise, the function of metallothioneins seems to be crucial in arsenic detoxification processes, after using both metallothionein knockout and knockdown strains and cells overexpressing metallothionein genes from this ciliate. The analysis of the differential toxicity of As(III) and As(V) shown in this study provides cytological and molecular tools to be used as biomarkers for each of the two arsenic ionic forms
Assessing soil contamination and temporal trends of heavy metal contents in greenhouses on semiarid land
Information about the behavior and temporal evolution of heavy metals in agricultural soils is limited, particularly about greenhouse soils on semiarid lands, indeed it nonexistent. Western Almería (Southern Spain) is a semiarid land where some 30,000 ha are occupied by greenhouses with high productivity. As these greenhouses are fundamental to the socioeconomic development of this area, they should be maintained and well conserved. However, there are indications that long‐term intensive agriculture with considerable agrochemicals use can deteriorate soil quality, which in turn, would reduce productivity and food quality. This study was conducted to investigate soil contamination and the temporal trends of heavy metal concentrations in greenhouse soils of western Almería. Contamination level, availability, and sources of metals were evaluated by the extractable fraction percentage, by indices zinc equivalent, geoaccumulation, enrichment factor and pollution load, and by a correlation analysis between soil properties and metal contents. The results showed that the total contents of Cd, Cu, Ni, and Pb, and the available concentration of Cd, Cu, Pb, and Zn, were significantly higher than background levels. Temporal patterns indicated that these elements accumulate in greenhouse soils. After more than 20 years of intensive agriculture, the available concentration of elements, and contamination, had clearly increased
Planets Around Low-Mass Stars (PALMS). I. A Substellar Companion to the Young M Dwarf 1RXS J235133.3+312720
We report the discovery of a brown dwarf companion to the young M dwarf 1RXS
J235133.3+312720 as part of a high contrast imaging search for planets around
nearby young low-mass stars with Keck-II/NIRC2 and Subaru/HiCIAO. The 2.4"
(~120 AU) pair is confirmed to be comoving from two epochs of high resolution
imaging. Follow-up low- and moderate-resolution near-infrared spectroscopy of
1RXS J2351+3127 B with IRTF/SpeX and Keck-II/OSIRIS reveals a spectral type of
L0. The M2 primary star 1RXS J2351+3127 A exhibits X-ray and UV
activity levels comparable to young moving group members with ages of ~10-100
Myr. UVW kinematics based the measured radial velocity of the primary and the
system's photometric distance (50 +/- 10 pc) indicate it is likely a member of
the ~50-150 Myr AB Dor moving group. The near-infrared spectrum of 1RXS
J2351+3127 B does not exhibit obvious signs of youth, but its H-band morphology
shows subtle hints of intermediate surface gravity. The spectrum is also an
excellent match to the ~200 Myr M9 brown dwarf LP 944-20. Assuming an age of
50-150 Myr, evolutionary models imply a mass of 32 +/- 6 Mjup for the
companion, making 1RXS J2351+3127 B the second lowest-mass member of the AB Dor
moving group after the L4 companion CD-35 2722 B and one of the few benchmark
brown dwarfs known at young ages.Comment: Accepted for publication in ApJ. 24 pages, 12 figures, 4 table
Pandemic and post-pandemic Influenza A (H1N1) infection in critically ill patients
Background: There is a vast amount of information published regarding the impact of 2009 pandemic Influenza A (pH1N1) virus infection. However, a comparison of risk factors and outcome during the 2010-2011 post-pandemic period has not been described. Methods: A prospective, observational, multi-center study was carried out to evaluate the clinical characteristics and demographics of patients with positive RT-PCR for H1N1 admitted to 148 Spanish intensive care units (ICUs). Data were obtained from the 2009 pandemic and compared to the 2010-2011 post-pandemic period. Results: Nine hundred and ninety-seven patients with confirmed An/H1N1 infection were included. Six hundred and forty-eight patients affected by 2009 (pH1N1) virus infection and 349 patients affected by the post-pandemic Influenza (H1N1)v infection period were analyzed. Patients during the post-pandemic period were older, had more chronic comorbid conditions and presented with higher severity scores (Acute Physiology And Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA)) on ICU admission. Patients from the post-pandemic Influenza (H1N1)v infection period received empiric antiviral treatment less frequently and with delayed administration. Mortality was significantly higher in the post-pandemic period. Multivariate analysis confirmed that haematological disease, invasive mechanical ventilation and continuous renal replacement therapy were factors independently associated with worse outcome in the two periods. HIV was the only new variable independently associated with higher ICU mortality during the post-pandemic Influenza (H1N1)v infection period. Conclusion: Patients from the post-pandemic Influenza (H1N1)v infection period had an unexpectedly higher mortality rate and showed a trend towards affecting a more vulnerable population, in keeping with more typical seasonal viral infection
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