Revisiting the Cooling Flow Problem in Galaxies, Groups, and Clusters of Galaxies

We present a study of 107 galaxies, groups, and clusters spanning ~3 orders of magnitude in mass, ~5 orders of magnitude in central galaxy star formation rate (SFR), ~4 orders of magnitude in the classical cooling rate (dM/dt) of the intracluster medium (ICM), and ~5 orders of magnitude in the central black hole accretion rate. For each system in this sample, we measure dM/dt using archival Chandra X-ray data and acquire the SFR and systematic uncertainty in the SFR by combining over 330 estimates from dozens of literature sources. With these data, we estimate the efficiency with which the ICM cools and forms stars, finding e_cool = SFR/(dM/dt) = 1.4 +/- 0.4% for systems with dM/dt > 30 Msun/yr. For these systems, we measure a slope in the SFR-dM/dt relation greater than unity, suggesting that the systems with the strongest cool cores are also cooling more efficiently. We propose that this may be related to, on average, higher black hole accretion rates in the strongest cool cores, which could influence the total amount (saturating near the Eddington rate) and dominant mode (mechanical vs radiative) of feedback. For systems with dM/dt < 30 Msun/yr, we find that the SFR and dM/dt are uncorrelated, and show that this is consistent with star formation being fueled at a low (but dominant) level by recycled ISM gas in these systems. We find an intrinsic log-normal scatter in SFR at fixed dM/dt of 0.52 +/- 0.06 dex, suggesting that cooling is tightly self-regulated over very long timescales, but can vary dramatically on short timescales. There is weak evidence that this scatter may be related to the feedback mechanism, with the scatter being minimized (~0.4 dex) in systems for which the mechanical feedback power is within a factor of two of the cooling luminosity.Comment: 16 pages, 10 figures, 6 tables. Submitted to ApJ. Comments welcome

ALMA observations of molecular clouds in three group centered elliptical galaxies: NGC 5846, NGC 4636, and NGC 5044

We present new ALMA CO(2--1) observations of two well studied group-centered elliptical galaxies: NGC~4636 and NGC~5846. In addition, we include a revised analysis of Cycle 0 ALMA observations of the central galaxy in the NGC~5044 group that has been previously published. We find evidence that molecular gas, in the form of off-center orbiting clouds, is a common presence in bright group-centered galaxies (BGG). CO line widths are $\gtrsim 10$ times broader than Galactic molecular clouds, and using the reference Milky Way $X_{CO}$, the total molecular mass ranges from as low as $2.6\times 10^5 M_\odot$ in NGC~4636 to $6.1\times 10^7 M_\odot$ in NGC~5044. With these parameters the virial parameters of the molecular structures is $\gg 1$. Complementary observations of NGC~5846 and NGC~4636 using the ALMA Compact Array (ACA) do not exhibit any detection of a CO diffuse component at the sensitivity level achieved by current exposures. The origin of the detected molecular features is still uncertain, but these ALMA observations suggest that they are the end product of the hot gas cooling process and not the result of merger events. Some of the molecular clouds are associated with dust features as revealed by HST dust extinction maps suggesting that these clouds formed from dust-enhanced cooling. The global nonlinear condensation may be triggered via the chaotic turbulent field or buoyant uplift. The large virial parameter of the molecular structures and correlation with the warm ($10^3 - 10^5 K$)/hot ($\ge10^6$) phase velocity dispersion provide evidence that they are unbound giant molecular associations drifting in the turbulent field, consistently with numerical predictions of the chaotic cold accretion process. Alternatively, the observed large CO line widths may be generated by molecular gas flowing out from cloud surfaces due to heating by the local hot gas atmosphere.Comment: Revised version to be published in ApJ, 16 pages, 10 figures, 4 table

Colloidal CuFeS2 Nanocrystals: Intermediate Fe d-Band Leads to High Photothermal Conversion Efficiency

We describe the colloidal hot-injection synthesis of phase-pure nanocrystals (NCs) of a highly abundant mineral, chalcopyrite (CuFeS2). Absorption bands centered at around 480 and 950 nm, spanning almost the entire visible and near infrared regions, encompass their optical extinction characteristics. These peaks are ascribable to electronic transitions from the valence band (VB) to the empty intermediate band (IB), located in the fundamental gap and mainly composed of Fe 3d orbitals. Laser-irradiation (at 808 nm) of an aqueous suspension of CuFeS2 NCs exhibited significant heating, with a photothermal conversion efficiency of 49%. Such efficient heating is ascribable to the carrier relaxation within the broad IB band (owing to the indirect VB-IB gap), as corroborated by transient absorption measurements. The intense absorption and high photothermal transduction efficiency (PTE) of these NCs in the so-called biological window (650-900 nm) makes them suitable for photothermal therapy as demonstrated by tumor cell annihilation upon laser irradiation. The otherwise harmless nature of these NCs in dark conditions was confirmed by in vitro toxicity tests on two different cell lines. The presence of the deep Fe levels constituting the IB is the origin of such enhanced PTE, which can be used to design other high performing NC photothermal agents.Comment: 12 pages, Chemistry of Materials, 31-May-201

Interpreting radiative efficiency in radio-loud AGNs

Author submitted version of unrefereed Nature Astronomy comment. Version in journal format available at https://rdcu.be/KH6WRadiative efficiency in radio-loud active galactic nuclei is governed by the accretion rate onto the central black hole rather than directly by the type of accreted matter; while it correlates with real differences in host galaxies and environments, it does not provide unambiguous information about particular objects.Non peer reviewedFinal Accepted Versio

Kinetic or thermal AGN feedback in simulations of isolated and merging disc galaxies calibrated by the M-\ua0 relation

We investigate two modes of coupling the feedback energy from a central active galacticnucleus (AGN) to the neighbouring gas in galaxy simulations: kinetic - velocity boost andthermal - heating. We formulate kinetic feedback models for energy-driven wind (EDW)and momentum-driven wind (MDW), using two free parameters: feedback efficiency \u3b5f and AGN wind velocity \u3bd w. A novel numerical algorithm is implemented in the smoothed particlehydrodynamics code GADGET-3, to prevent the expansion of a hole in the gas distributionaround the black hole (BH). We perform simulations of isolated evolution and merger ofdisc galaxies, of Milky Way mass as well as lower and higher masses. We find that in theisolated galaxy BH kinetic feedback generates intermittent bipolar jet-like gas outflows. Weinfer that current prescriptions for BH subgrid physics in galaxy simulations can grow theBH to observed values even in an isolated disc galaxy. The BH growth is enhanced in agalaxy merger, which consequently requires different model parameters to fit the observationsthan an isolated case. Comparing the [MBH-\u3c3*] relation obtained in our simulations withobservational data, we conclude that it is possible to find parameter sets for a fit in all themodels (e.g. \u3bdw = 10 000 km s-1 and \u3b5f = 0.25 for BH kinetic EDW), except for the casewith MDW feedback in a galaxy merger, in which the BH is always too massive. The BHthermal feedback implementation of Springel et al. within the multiphase star formation modelis found to have negligible impact on gas properties, and the effect claimed in all previousstudies is attributed to gas depletion around the BH by the creation of an artificial hole. TheBH mass accretion rate in our simulations exhibit heavy fluctuations. The star formation rate isquenched with feedback by removal of gas. The circumgalactic medium gas at galactocentricdistances (20-100) h-1 kpc is found to give the best metallicity observational diagnostic todistinguish between BH model

The use of building performance simulation to support architectural design: a case study

Abstract Considering the complex interaction between energy performance, lighting, acoustic and thermal comfort in contemporary design, building performance simulation [BPS] shall play a key role in addressing decision making process and technical choices towards optimized configuration during the whole design phase. The paper reports the outcomes of a case study – performed in the framework of Ma Final Design Lab at the Department of Architecture, University of Bologna – where BPS was adopted from the very beginning as a tool to support the design process from the concept validation to the final architectural configuration to fit with passive house standards

Evaluation of two years aged Populus clones, in two microsites of the pampean region, Argentina

La producción de álamos en la pampa ondulada de la provincia de Buenos Aires podría constituir una actividad alternativa y/o complementaria, debido a zonas ecológicas favorables para su cultivo. En este contexto es importante conocer el comportamiento de los clones en los diversos ambientes para poder definir cuáles de ellos podrían presentar mayor estabilidad para los diferentes sitios. El objetivo del trabajo fue estudiar la interacción existente entre los parámetros de crecimiento y supervivencia de 16 clones de Populus spp. en dos micrositios geomorfológicamente diferentes en la región pampeana, Argentina. Los clones en estudio provienen de cruzamientos intraespecíficos de P. deltoides e interespecíficos de P. deltoides x P. nigra (Populus x canadensis). Se plantaron en dos ensayos, uno por cada situación geomórfica: loma y bajo, y se completó con un análisis estadístico comparando los ensayos en forma individual y conjunta. Cada ensayo se instaló con un diseño de bloques completos al azar. Las variables analizadas fueron la supervivencia, la altura media y el área basal al concluir el segundo año de crecimiento. Para el sitio regional evaluado, la interacción entre los clones y los micrositios fue significativa para las variables altura y supervivencia. La mayor disponibilidad de agua en el micrositio bajo produjo mayores crecimientos clonales con diferencias significativas respecto del micrositio loma. La estabilidad de los atributos de supervivencia y crecimiento frente a los micrositios es un objetivo fundamental en las plantaciones clonales. Siendo los micrositios una realidad ambiental importante, propia como variable no controlable, la reducción de la variabilidad de respuesta ante ellos permitiría la constitución de unidades de manejo más homogéneas.Poplar production in the pampean region of the province of Buenos Aires could become an altenative and/or complementary activity, because of the ecological conditions for its cultivation. It is within this context that is important to know the behaviour of the clones in the different environments, in order to define which ones could present more stability in the different sites. The aim of this work was to study the interaction between the growth and the survival parameters of 16 clones of Populus spp., in two geomorphologycal different micro-sites, in the pampean region of Argentina. The studied clones were planted in two different essays, one for each geomorphic situation: hill and lowland. A statistic analysis was done in order to compare the essays in an individual and in a combined way. Each essay was installed with a randomized block design. The analyzed variables by the end of the second year of growth were survival, mean height and basal area. For the evaluated region, the interaction between clones and micro sites was significant for height and survival. The mayor water availability in the lowland micro-site produced mayor clone growth, with significant differences with the hill micro-site. The stability of survival and growth in the micro-sites is one of the principal objects in a clone plantation. Being the microsite a huge environmental reality, as a non controllable variable, the reduction of variability in the response, will allow the construction of more homogeneous management units.Fil: Senisterra, Gabriela E..Fil: Ducid, María G..Fil: Gaspari, Fernanda J..Fil: Delgado, María Isabel

Metrological characterization of MEMS accelerometers by LDV

Abstract In this work two calibration methodologies, able to characterize the digital sensitivity of MEMS accelerometers, are presented and compared, to identify the contributions for the evaluation of the reproducibility in the low frequency range. The methodologies are different from the point of view of test bench, test procedure and data processing method. In particular, different vibration actuators are used, a linear slide and an electro-dynamic shaker, different sensors as a reference for the calibration, piezoelectric accelerometers and a Laser Doppler Vibrometer (LDV). A group of 5 accelerometers is tested for the purpose of developing the calibration techniques and evaluate a first reproducibility estimate. The experimental results provided by the two calibration procedures show significant differences. Some elements that could explain these differences have been identified, and will be further investigated in future work

Laparoscopic single-port sleeve gastrectomy for morbid obesity: preliminary series

Laparoscopic sleeve gastrectomy has been recently proposed as a sole bariatric procedure because of the resulting considerable weight loss in morbidly obese patients. Traditionally, laparoscopic sleeve gastrectomy requires 5-6 skin incisions to allow for placement of multiple trocars. With the introduction of single-incision laparoscopic surgery, multiple abdominal procedures have been performed using a sole umbilical incision, with good cosmetic outcomes. The purpose of our study was to evaluate the feasibility and safety of laparoscopic single incision sleeve gastrectomy for morbid obesity

Analysis of Dictyostelium discoideum Inositol Pyrophosphate Metabolism by Gel Electrophoresis.

The social amoeba Dictyostelium discoideum was instrumental in the discovery and early characterization of inositol pyrophosphates, a class of molecules possessing highly-energetic pyrophosphate bonds. Inositol pyrophosphates regulate diverse biological processes and are attracting attention due to their ability to control energy metabolism and insulin signalling. However, inositol pyrophosphate research has been hampered by the lack of simple experimental procedures to study them. The recent development of polyacrylamide gel electrophoresis (PAGE) and simple staining to resolve and detect inositol pyrophosphate species has opened new investigative possibilities. This technology is now commonly applied to study in vitro enzymatic reactions. Here we employ PAGE technology to characterize the D. discoideum inositol pyrophosphate metabolism. Surprisingly, only three major bands are detectable after resolving acidic extract on PAGE. We have demonstrated that these three bands correspond to inositol hexakisphosphate (IP6 or Phytic acid) and its derivative inositol pyrophosphates, IP7 and IP8. Biochemical analyses and genetic evidence were used to establish the genuine inositol phosphate nature of these bands. We also identified IP9 in D. discoideum cells, a molecule so far detected only from in vitro biochemical reactions. Furthermore, we discovered that this amoeba possesses three different inositol pentakisphosphates (IP5) isomers, which are largely metabolised to inositol pyrophosphates. Comparison of PAGE with traditional Sax-HPLC revealed an underestimation of the cellular abundance of inositol pyrophosphates by traditional methods. In fact our study revealed much higher levels of inositol pyrophosphates in D. discoideum in the vegetative state than previously detected. A three-fold increase in IP8 was observed during development of D. discoideum a value lower that previously reported. Analysis of inositol pyrophosphate metabolism using ip6k null amoeba revealed the absence of developmentally-induced synthesis of inositol pyrophosphates, suggesting that the alternative class of enzyme responsible for pyrophosphate synthesis, PP-IP5K, doesn't' play a major role in the IP8 developmental increase