199 research outputs found

    Cosmic web alignments with the shape, angular momentum and peculiar velocities of dark matter haloes

    Full text link
    We study the alignment of dark matter haloes with the cosmic web characterized by the tidal and velocity shear fields. We focus on the alignment of their shape, angular momentum and peculiar velocities. We use a cosmological N-body simulation that allows to study dark matter halos spanning almost five orders of magnitude in mass (10910^{9}-101410^{14}) h1h^{-1}MM_{\odot} and spatial scales of (0.5(0.5-1.0)1.0) h1h^{-1} Mpc to define the cosmic web. We find that the halo shape presents the strongest alignment along the smallest tidal eigenvector, e.g. along filaments and walls, with a signal that gets stronger as the halo mass increases. In the case of the velocity shear field only massive halos >1012>10^{12} h1h^{-1}MM_{\odot} tend to have their shapes aligned along the largest tidal eigenvector; that is, perpendicular to filaments and walls. For the angular momentum we find alignment signals only for halos more massive than 101210^{12} h1h^{-1}MM_{\odot} both in the tidal and velocity shear webs where the preferences are for it to be parallel to the middle eigenvector; perpendicular to filaments and parallel to walls. Finally, the peculiar velocities show a strong alignment along the smallest tidal eigenvector for all halo masses; halos move along filaments and walls. In the velocity shear the same alignment is present but weaker and only for haloes less massive than 101210^{12} h1h^{-1}MM_{\odot}. Our results clearly show that the two different algorithms we used to define the cosmic web describe different physical aspects of non-linear collapse and should be used in a complementary way to understand the effect of the cosmic web on galaxy evolution.Comment: 14 pages, 5 figures, MNRAS accepte

    Galactic conformity measured in semi-analytic models

    Get PDF
    We study the correlation between the specific star formation rate of central galaxies and neighbour galaxies, also known as 'galactic conformity', out to 20 Mpc/h using three semi-analytic models (SAMs, one from L-GALAXIES and other two from GALFORM). The aim is to establish whether SAMs are able to show galactic conformity using different models and selection criteria. In all the models, when the selection of primary galaxies is based on an isolation criterion in real space, the mean fraction of quenched galaxies around quenched primary galaxies is higher than that around star-forming primary galaxies of the same stellar mass. The overall signal of conformity decreases when we remove satellites selected as primary galaxies, but the effect is much stronger in GALFORM models compared with the L-GALAXIES model. We find this difference is partially explained by the fact that in GALFORM once a galaxy becomes a satellite remains as such, whereas satellites can become centrals at a later time in L-GALAXIES. The signal of conformity decreases down to 60% in the L-GALAXIES model after removing central galaxies that were ejected from their host halo in the past. Galactic conformity is also influenced by primary galaxies at fixed stellar mass that reside in dark matter haloes of different masses. Finally, we explore a proxy of conformity between distinct haloes. In this case the conformity is weak beyond ~ 3 Mpc/h (<3% in L-GALAXIES, <1-2% in GALFORM models). Therefore, it seems difficult that conformity is directly related with a long-range effect.Comment: 15 pages, 7 figures. Accepted for publication in MNRA

    On the Prospect of Using the Maximum Circular Velocity of Halos to Encapsulate Assembly Bias in the Galaxy–Halo Connection

    Get PDF
    We investigate a conceptual modification of the halo occupation distribution approach, using the halos’ present-day maximal circular velocity, Vmax, as an alternative to halo mass. In particular, using a semianalytic galaxy formation model applied to the Millennium WMAP7 simulation, we explore the extent that switching to Vmax as the primary halo property incorporates the effects of assembly bias into the formalism. We consider fixed number density galaxy samples ranked by stellar mass and examine the variations in the halo occupation functions with either halo concentration or formation time. We find that using Vmax results in a significant reduction in the occupancy variation of the central galaxies, particularly for concentration. The satellites’ occupancy variation on the other hand increases in all cases. We find effectively no change in the halo clustering dependence on concentration, for fixed bins of Vmax compared to fixed halo mass. Most crucially, we calculate the impact of assembly bias on galaxy clustering by comparing the amplitude of clustering to that of a shuffled galaxy sample, finding that the level of galaxy assembly bias remains largely unchanged. Our results suggest that while using Vmax as a proxy for halo mass diminishes some of the occupancy variations exhibited in the galaxy–halo relation, it is not able to encapsulate the effects of assembly bias potentially present in galaxy clustering. The use of other more complex halo properties, such as Vpeak, the peak value of Vmax over the assembly history, provides some improvement and warrants further investigation

    Metastatic pheochromocytoma to liver without elevation of metanephrines and catecholamines

    Get PDF
    AbstractIntroductionMalignant pheochromocytoma represents 10% of all patients with pheochromocytoma. Of these cases, only 5–9% presents without elevation of metanephrines and catecholamines.Presentation of caseA 43-year-old female patient presented with an abdominal tumor. An exploratory laparotomy was performed and the final report was a pheochromocytoma. After ten years, multiple liver lesions were detected and surgical treatment was performed. Pathological evaluation revealed a malignant pheochromocytoma with negative margins after 5 years of follow-up without evidence of disease.DiscussionThe recurrence rate of malignant pheochromocytoma is 15–20% at ten years and a 5-year survival rate that ranges from 50% to 80%. The presence of synchronous metastases is rare (10–27%), but have been reported until 20 years later with the most common metastatic sites being the local lymph nodes, bone (50%), liver (50%) and lung (30%). The prognostic factor such as size >6cm, age over 45 years, synchronous metastasis and no tumor excision are related with poor prognosis.ConclusionSurgical treatment offers the best survival rate and the only chance of cure so far and the goal is an R0 resection as in our case. So it should be the treatment of choice

    Occupation sequence and building development in the settlement of Caramoro I (Elche, Alicante): contributions to Argaric architecture

    Get PDF
    A pesar de que la cultura de El Argar es una de las entidades arqueológicas mejor conocidas del ámbito peninsular, no son muchos los trabajos efectuados sobre los aspectos arquitectónicos y del desarrollo constructivo de los asentamientos argáricos excavados. En este artículo se presentan las formas arquitectónicas, las técnicas y materiales constructivos empleados y la secuencia de ocupación del asentamiento de Caramoro I (Elche, Alicante) a partir del análisis estratigráfico y de estructuras conservadas, reforzada y avalada con una serie de dataciones absolutas sobre muestras de vida corta. Los resultados obtenidos han mostrado que Caramoro I fue un asentamiento de carácter agropecuario, ubicado en los límites fronterizos septentrionales de El Argar, que fue reformado con la intención de mejorar su protección y defensa, a partir de la fortificación de su zona de acceso. Sus concomitancias con otros asentamientos similares en territorios de frontera más orientales vienen a mostrar su carácter logístico.Although El Argar culture is one of the best-known archaeological entities in the Iberian Peninsula, there are not many works published on the architectural aspects and constructive development of the Argaric settlements which have been excavated. This article presents the architectural forms, construction techniques and materials and the occupation sequence of the settlement of Caramoro I (Elche, Alicante), based on the stratigraphic analysis and preserved structures, reinforced with a series of absolute dates on short life samples. The results obtained have shown that Caramoro I was a settlement of agricultural orientation, located in the northern borders of the El Argar territory, reformed to improve its protection and defense, with the fortification of its access. Its similarities with other settlements in the Eastern border territories show the logistical function of Caramoro I.El presente trabajo ha sido realizado en el marco del proyecto de investigación “Espacios sociales y espacios de frontera durante el Calcolítico y la Edad del Bronce en el Levante de la península ibérica” (HAR2016-76586-P), financiado por el Ministerio de Economía y Competitividad del Gobierno de España

    An Iconoclastic Society? New Bovid Terracottas from the Argaric Site of Laderas del Castillo (Callosa de Segura, Alicante, Spain)

    Get PDF
    Se presenta el hallazgo de nuevas terracotas de bóvidos del asentamiento argárico de Laderas del Castillo. Su presencia en contextos de la Edad del Bronce ya no es un unicum y permite reabrir el debate sobre el carácter iconoclasta de El Argar y su vinculación con el mundo mediterráneo.We present the discovery of new terracotta figurines of bovids from the Argaric settlement of Laderas del Castillo. Their presence in Bronze Age sites is no longer an anomaly, and allows us to reopen the debate on the iconoclastic character of El Argar and its connection with the Mediterranean world.Este trabajo ha sido realizado dentro del proyecto «Espacios sociales y espacios de frontera durante el Calcolítico y la Edad del Bronce en el Levante de la península ibérica» (HAR2016-76586-P), financiado por el Ministerio de Economía y Competitividad de España

    Early changes in inflammatory and pro-thrombotic biomarkers in patients initiating antiretroviral therapy with abacavir or tenofovir

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Abacavir has been associated with an increased risk of acute myocardial infarction, but the pathogenic mechanisms remain unknown. We evaluated longitudinal changes in pro-atherosclerotic biomarkers in patients initiating abacavir or tenofovir.</p> <p>Methods</p> <p>Consecutive patients initiating antiretroviral therapy (ART) with abacavir/lamivudine or tenofovir/emtricitabine were included. Plasma levels of high sensitivity C reactive protein (hsCRP), interleukin-6 (IL-6), intercellular adhesion molecule-1, vascular cell adhesion molecule-1 (sVCAM-1) and plasminogen activator inhibitor-1 (PAI-1) were measured at baseline and at different time points throughout 48 weeks. Comparisons were adjusted for age, sex, ART status at inclusion, viral load, lipodystrophy, Framingham score and hepatitis C virus co-infection status.</p> <p>Results</p> <p>50 patients were analyzed, 28 initiating abacavir and 22 tenofovir. The endothelial biomarker sVCAM-1 declined significantly in both treatment groups. hsCRP tended to increase soon after starting therapy with abacavir, a trend that was not seen in those initiating tenofovir. IL-6 significantly increased only at week 24 from baseline in patients on abacavir (+225%, p < 0.01) although the differences were not significant between groups. The procoagulant biomarker PAI-1 plasma levels increased from baseline at week 12 (+57%; p = 0.017), week 24 (+72%; p = 0.008), and week 48 (+149%; p < 0.001) in patients on tenofovir, but differences between groups were not statistically significant.</p> <p>Conclusion</p> <p>Changes in biomarkers of inflammation, coagulation, and endothelial function are not different in viremic patients starting ART with abacavir/lamivudine or tenofovir/emtricitabine. These changes occur in the early phases of treatment and include anti- and pro-atherosclerotic effects with both drugs.</p

    Using regression tree analysis to determine size class intervals and sexual dimorphism in the Morelet's crocodile Crocodylus moreletii

    Get PDF
    Assignment of Morelet's crocodile Crocodylus moreletii individuals into size groups or classes based on ecological and morphological similarities has not yet been associated with species-specific ontogeny related changes. Age or size of first reproductive behavior is not precisely known for C. moreletii, but differences in allometric patterns and relative cranial size between juveniles and adults might be used as an indicator of sexual maturity. In this study, a regression tree analysis was used to investigate the relationship between age and body size in 1266 crocodiles by using both simple and generalized linear models, with gender and origin (captivity or wild) as factors. Total length (TL), snout–vent length (SVL) and cranial length (CL) were used as predictor variables and the logarithm of body mass as the response variable. Four length intervals with well-defined thresholds (514, 899 and 1497 mm of TL) were established using all three predictors (TL, SVL and CL). Relationship between SVL and TL was described, and a strong positive relationship (r2 = 0.98), unaffected by crocodile gender, was observed. The observed CL–TL and CL–SVL relationships were also positive but significantly different between males and females (p < 0.001) and length interval classes (p = 0.01). These results suggest that our estimated size thresholds seem to correspond to important ontogenetic changes in C. moreletii and that sexual maturity is closely related to size in this species, where sexual dimorphism in body length occurs, particularly in large individuals (size group IV)

    Physical Violence or Accident? New Data on a Child Burial from the Argaric Site of Caramoro I (Elche, Alicante, Spain)

    Get PDF
    Se presentan nuevos datos sobre el enterramiento infantil del asentamiento argárico de Caramoro I. Los argumentos permiten reflexionar y considerar otra interpretación alternativa a la hipótesis de violencia física inicialmente propuesta.New data on a child burial from the Argaric settlement of Caramoro I is presented. The arguments allow us to consider an alternative interpretation to the initial hypothesis of physical violence.Este trabajo ha sido realizado en el marco del proyecto de investigación «Espacios sociales y espacios de frontera durante el Calcolítico y la Edad del Bronce en el Levante de la península ibérica» (HAR2016-76586-P), financiado por el Ministerio de Economía y Competitividad de España

    The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

    Get PDF
    The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected
    corecore