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

Time Domain Simulations of the CLIC PETS (Power Extraction and Transfer Structure) with GdfidL

The Compact Linear Collider (CLIC) PETS is required to produce about 0.5 GW RF power per metre in the 30 GHz CLIC decelerator when driven by the high current beam (~ 270 A). To avoid beam break-up in the decelerator it is necessary to provide strong damping of the transverse deflecting modes. A PETS geometry with a level of damping consistent with stable drive beam operation has been designed, using the frequency domain code HFSS. A verification of the overall performance of this structure has been made recently using the code GdfidL, which permits a very fine mesh analysis of a full-length structure in the time domain. This paper gives the results of this analysis

Equity-Efficiency Optimizing Resource Allocation: The Role of Time Preferences in a Repeated Irrigation Game

We study repeated water allocation decisions among small scale irrigation users in Tanzania. In a treatment replicating water scarcity conditions, convexities in production make that substantial efficiency gains can be obtained by deviating from equal sharing, leading to an equity–efficiency trade-off. In a repeated game setting, it becomes possible to reconcile efficiency with equity by rotating the person who receives the largest share, but such a strategy requires a longer run perspective. Correlating experimental data from an irrigation game with individual time preference data, we find that less patient irrigators are less likely to use a rotation strategy

Sparsity of integer solutions in the average case

We examine how sparse feasible solutions of integer programs are, on average. Average case here means that we fix the constraint matrix and vary the right-hand side vectors. For a problem in standard form with m equations, there exist LP feasible solutions with at most m many nonzero entries. We show that under relatively mild assumptions, integer programs in standard form have feasible solutions with O(m) many nonzero entries, on average. Our proof uses ideas from the theory of groups, lattices, and Ehrhart polynomials. From our main theorem we obtain the best known upper bounds on the integer Carathéodory number provided that the determinants in the data are small

Fungi isolated from Miscanthus and sugarcane: biomass conversion, fungal enzymes, and hydrolysis of plant cell wall polymers.

BackgroundBiofuel use is one of many means of addressing global change caused by anthropogenic release of fossil fuel carbon dioxide into Earth's atmosphere. To make a meaningful reduction in fossil fuel use, bioethanol must be produced from the entire plant rather than only its starch or sugars. Enzymes produced by fungi constitute a significant percentage of the cost of bioethanol production from non-starch (i.e., lignocellulosic) components of energy crops and agricultural residues. We, and others, have reasoned that fungi that naturally deconstruct plant walls may provide the best enzymes for bioconversion of energy crops.ResultsPreviously, we have reported on the isolation of 106 fungi from decaying leaves of Miscanthus and sugarcane (Appl Environ Microbiol 77:5490-504, 2011). Here, we thoroughly analyze 30 of these fungi including those most often found on decaying leaves and stems of these plants, as well as four fungi chosen because they are well-studied for their plant cell wall deconstructing enzymes, for wood decay, or for genetic regulation of plant cell wall deconstruction. We extend our analysis to assess not only their ability over an 8-week period to bioconvert Miscanthus cell walls but also their ability to secrete total protein, to secrete enzymes with the activities of xylanases, exocellulases, endocellulases, and beta-glucosidases, and to remove specific parts of Miscanthus cell walls, that is, glucan, xylan, arabinan, and lignin.ConclusionThis study of fungi that bioconvert energy crops is significant because 30 fungi were studied, because the fungi were isolated from decaying energy grasses, because enzyme activity and removal of plant cell wall components were recorded in addition to biomass conversion, and because the study period was 2 months. Each of these factors make our study the most thorough to date, and we discovered fungi that are significantly superior on all counts to the most widely used, industrial bioconversion fungus, Trichoderma reesei. Many of the best fungi that we found are in taxonomic groups that have not been exploited for industrial bioconversion and the cultures are available from the Centraalbureau voor Schimmelcultures in Utrecht, Netherlands, for all to use

How present aerosol pollution from North America impacts North Atlantic climate

This paper describes the potential effects of present-day aerosol pollution from North America (USA, Canada) on the climate of the North Atlantic region. The study has been performed by applying the comprehensive atmospheric general circulation model ECHAM5-HAM, which is coupled to a mixed-layer ocean with an embedded thermodynamic sea ice module. The model includes a microphysical aerosol model (HAM), which allows for the assessment of aerosol impacts on climate. Sulphate, black and organic carbon, sea salt and mineral dust are considered as aerosol species. Two equilibrium simulations with two different aerosol pollutant scenarios are compared for each season. We investigate the effect on radiation, temperature, hydrological quantities and dynamics, when human-induced aerosol emissions from North America were omitted. The decrease of both direct and indirect aerosol effects induces a positive change in top of the atmosphere (TOA) radiative fluxes resulting in an overall warming in the whole region. Our results demonstrate the vulnerability especially of the Arctic to the reduction in aerosol load. For fall we find an increase in precipitation over the North Atlantic, associated with a tendency to a larger number of cyclones with high-pressure gradients and a higher frequency in storm days

Das Rundum-Klimapaket

Die Erderwärmung verändert die Welt – ökologisch, ökonomisch und politisch. Klimadienste wollen Entscheidungsträgern helfen, auf den vielfältigen Wandel angemessen zu reagieren. Unsere Autoren waren maßgeblich am Aufbau des Climate Service Center in Hamburg beteiligt. Im Folgenden stellen sie die Arbeit dieser Art von Einrichtungen vor und schildern die Herausforderungen für die Kommunikation

The amalgamated duplication of a ring along a multiplicative-canonical ideal

After recalling briefly the main properties of the amalgamated duplication of a ring $R$ along an ideal $I$, denoted by R\JoinI, we restrict our attention to the study of the properties of R\JoinI, when $I$ is a multiplicative canonical ideal of $R$ \cite{hhp}. In particular, we study when every regular fractional ideal of $R\Join I$ is divisorial

Permutation branes and linear matrix factorisations

All the known rational boundary states for Gepner models can be regarded as permutation branes. On general grounds, one expects that topological branes in Gepner models can be encoded as matrix factorisations of the corresponding Landau-Ginzburg potentials. In this paper we identify the matrix factorisations associated to arbitrary B-type permutation branes.Comment: 43 pages. v2: References adde