Relative and contextual contribution of different sources to the composition and abundance of indoor air bacteria in residences.

BackgroundThe study of the microbial communities in the built environment is of critical importance as humans spend the majority of their time indoors. While the microorganisms in living spaces, especially those in the air, can impact health and well-being, little is known of their identity and the processes that determine their assembly. We investigated the source-sink relationships of airborne bacteria in 29 homes in the San Francisco Bay Area. Samples taken in the sites expected to be source habitats for indoor air microbes were analyzed by 16S rRNA-based pyrosequencing and quantitative PCR. The community composition was related to the characteristics of the household collected at the time of sampling, including the number of residents and pets, activity levels, frequency of cooking and vacuum cleaning, extent of natural ventilation, and abundance and type of vegetation surrounding the building.ResultsIndoor air harbored a diverse bacterial community dominated by Diaphorobacter sp., Propionibacterium sp., Sphingomonas sp., and Alicyclobacillus sp. Source-sink analysis suggested that outdoor air was the primary source of indoor air microbes in most homes. Bacterial phylogenetic diversity and relative abundance in indoor air did not differ statistically from that in outdoor air. Moreover, the abundance of bacteria in outdoor air was positively correlated with that in indoor air, as would be expected if outdoor air was the main contributor to the bacterial community in indoor bioaerosols. The number of residents, presence of pets, and local tap water also influenced the diversity and size of indoor air microbes. The bacterial load in air increased with the number of residents, activity, and frequency of natural ventilation, and the proportion of bacteria putatively derived from skin increased with the number of residents. Vacuum cleaning increased the signature of pet- and floor-derived bacteria in indoor air, while the frequency of natural ventilation decreased the relative abundance of tap water-derived microorganisms in air.ConclusionsIndoor air in residences harbors a diverse bacterial community originating from both outdoor and indoor sources and is strongly influenced by household characteristics

Il testo consonantico della tradizione babilonese. Ms. Opp.Add. 4 154 della Biblioteca Bodleiana

This paper is part of a project on manuscripts carried on under the auspices of Prof. Paolo Sacchi. It deals with Ms. Opp.Add. 4 154 of the Bodleian Library, of Yemenite provenance. The comparison of its readings with the variants collected by Kennicott and De Rossi and the old translations confirms the results described in the first part of this project: the Babylonian text (BT) is old and similar to the Tiberian one and their common basis is the old Hebrew Bible. The agreements of the BT with Aquila, Theodotion, Symmachus, Origen, and Hieronymus show that this text was current in Palestine at least until the 4th century AD. When the Tiberian text supplanted the Babylonian in the 10th century, the BT still survived in Yemenite communities. Many variants of the BT are attested in Ashkenazi MSS, and conse­quently in the Soncino Bible.Este artículo forma parte de un proyecto sobre manuscritos llevado a cabo bajo los auspicios del Prof. Paolo Sacchi. Estudia el Ms. Opp.Add. 4 154 de la Biblioteca Bodleiana, de proveniencia yemení. La comparación de sus lecturas con las variantes recogidas por Kennicott y De Rossi y con las versiones antiguas confirma los resultados descritos en la primera parte de ese proyecto: el texto babilónico (TB) es antiguo y similar al tiberiense y su base común es el antiguo texto hebreo. Las coincidencias del TB con Aquila, Teodoción, Symmaco, Orígenes y Jerónimo muestran que ese texto era corriente en Palestina al menos hasta el siglo IV d. C. Cuando el texto tiberiense suplantó al babilónico en el siglo X, el TB toda vía pervivía en comunidades yemeníes. Muchas variantes del TB están atestiguadas en manuscritos askenazíes y, consecuentemente, en la Biblia de Soncino

Preliminary study to investigate the Delboeuf illusion in ring-tailed lemurs (Lemur catta): Methodological challenges

Visual illusions are commonly used in animal cognition studies to compare visual perception among vertebrates. To date, researchers have focused their attention mainly on birds and mammals, especially apes and monkeys, but no study has investigated sensitivity to visual illusions in prosimians. Here we investigated whether lemurs (Lemur catta) perceive the Delboeuf illusion, a well-known illusion that occurs when subjects misperceive the relative size of an item because of its surrounding context. In particular, we adopted the spontaneous preference paradigm used in chimpanzees and observed lemurs’ ability to select the larger amount of food. In control trials, we presented two different amounts of food on two identical plates. In test trials, we presented equal food portion sizes on two plates differing in size: If lemurs were sensitive to the illusion, they were expected to select the food portion presented on the smaller plate. In control trials, they exhibited poor performance compared to other mammals previously observed, being able to discriminate between the two quantities only in the presence of a 0.47 ratio. This result prevented us from drawing any conclusion regarding the subjects’ susceptibility to the Delboeuf illusion. In test trials with the illusory pattern, however, the subjects’ choices did not differ from chance. Our data suggest that the present paradigm is not optimal for testing the perception of the Delboeuf illusion in lemurs and highlight the importance of using different methodological approaches to assess the perceptual mechanisms underlying size discrimination among vertebrates

Dispersal in microbes: fungi in indoor air are dominated by outdoor air and show dispersal limitation at short distances.

The indoor microbiome is a complex system that is thought to depend on dispersal from the outdoor biome and the occupants' microbiome combined with selective pressures imposed by the occupants' behaviors and the building itself. We set out to determine the pattern of fungal diversity and composition in indoor air on a local scale and to identify processes behind that pattern. We surveyed airborne fungal assemblages within 1-month time periods at two seasons, with high replication, indoors and outdoors, within and across standardized residences at a university housing facility. Fungal assemblages indoors were diverse and strongly determined by dispersal from outdoors, and no fungal taxa were found as indicators of indoor air. There was a seasonal effect on the fungi found in both indoor and outdoor air, and quantitatively more fungal biomass was detected outdoors than indoors. A strong signal of isolation by distance existed in both outdoor and indoor airborne fungal assemblages, despite the small geographic scale in which this study was undertaken (<500 m). Moreover, room and occupant behavior had no detectable effect on the fungi found in indoor air. These results show that at the local level, outdoor air fungi dominate the patterning of indoor air. More broadly, they provide additional support for the growing evidence that dispersal limitation, even on small geographic scales, is a key process in structuring the often-observed distance-decay biogeographic pattern in microbial communities

Ultrafast Modification of the Polarity at LaAlO3_3/SrTiO3_3 Interfaces

Oxide growth with semiconductor-like accuracy has led to atomically precise thin films and interfaces that exhibit a plethora of phases and functionalities not found in the oxide bulk material. This yielded spectacular discoveries such as the conducting, magnetic or even superconducting LaAlO$_3$/SrTiO$_3$ interfaces separating two prototypical insulating perovskite materials. All these investigations, however, consider the static state at the interface, although studies on fast oxide interface dynamics would introduce a powerful degree of freedom to understanding the nature of the LaAlO$_3$/SrTiO$_3$ interface state. Here we show that the polarization state at the LaAlO$_3$/SrTiO$_3$ interface can be optically enhanced or attenuated within picoseconds. Our observations are explained by a model based on charge propagation effects in the interfacial vicinity and transient polarization buildup at the interface