Systematic studies on the subtribe Disinae (Orchidaceae)

Bibliography: pages 126-138.The subtribe Disinae (Orchidaceae) has been revised over its whole distribution range (Sub-Saharan Africa and including the Yemen, Madagascar and Reunion). One hundred and sixty-five species arranged in 5 genera are recognized. Three new subspecies, 12 new species, 18 new series, 8 new sections and 7 new subgenera are described. Where deemed necessary, the species are grouped into subgenera, sections and series to indicate their interrelationships. Distribution maps were prepared for all the species, and the ecology and nomenclature of every species is discussed, while many are illustrated. The revision is based primarily on morphological data. In complex situations the variation is displayed by scatter diagrams. Both artificial and natural keys are reduced for the large genus Disa. The grouping of the sections and genera is analysed both by computer-based phenetic analyses, using the BOLAID program, and by Hennigian phylogenetic studies. The eventual classification is based on the phylogenetic scheme. The groupings produced by the two methods are compared and discussed and the theoretical bases of classifications are briefly discussed. The phytogeography of the subtribe is analysed in some detail. Centres of endemism are delimited, and their interrelationships are analysed, together with the patterns of species and above-species richness. The history of the subtribe is analysed using the taxonomic rank of the disjunctions between the centres as an indication of the age of the disjunctions. The postulated history is then compared to modern ideas on the recent African palaeoenvironments. On this evidence it is suggested that the Disinae migrated northwards from an early diversification in southern Africa, and that the present patterns have been much influenced by climatic changes in the last 50 000 years

Synoptic taxonomy of cortaderia stapf (danthonioideae, poaceae)

Cortaderia (Poaceae; Danthonioideae) is a medium-sized genus of C3 tussock grasses, widespread in the temperate to tropic-alpine regions of South America. It is particularly important in the subalpine and alpine zones of the Andes. We revised the classification of the genus, and recognize 17 species grouped into five informal groups. We describe one new species, Cortaderia echinata H.P.Linder, from Peru. We provide a key to the groups and the species, complete nomenclature for each species including new lectotypes, and notes on the ecology, distribution and diagnostic morphological and anatomical characters.Fil: Testoni, Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias Biológicas y Biomédicas del Sur. Universidad Nacional del Sur. Departamento de Biología, Bioquímica y Farmacia. Instituto de Ciencias Biológicas y Biomédicas del Sur; ArgentinaFil: Linder, H. Peter. Universitat Zurich; Suiz

Phylogeny and Historical Ecology of Rhodocoma (Restionaceae) from the Cape Floristic Region

A macroevolutionary analysis of macroecological relationships in Rhodocoma revealed a complex history of rapid ecological divergence, as well as genetic isolation via shifts in flowering times. The rate and extent of divergence observed among even the youngest of species pairs indicated that the selective forces driving these processes are strong enough to effect substantial amounts of ecological change in relatively short periods of time, and are potentially important factors promoting the origin and persistence of species diversity not only in Rhodocoma, but also the African Restionaceae as a whole. These results also suggest that the rate and extent of ecological differentiation can vary between lineages, and this may be a consequence of variations in the intensities of selective regimes or phylogenetic constraints that different lineages experience. Investigation into the nature of this differentiation revealed that much of it has occurred along altitudinal gradients, but in tandem with substantial shifts in other ecological parameters such as rainfall and fire survival. This multidimensionality of ecological differentiation increases the number of possible combinations of ecological parameters and may allow for a more precise partitioning of niche space

First Weak-lensing Results from "See Change": Quantifying Dark Matter in the Two Z>1.5 High-redshift Galaxy Clusters SPT-CL J2040-4451 and IDCS J1426+3508

We present a weak-lensing study of SPT-CLJ2040-4451 and IDCSJ1426+3508 at z=1.48 and 1.75, respectively. The two clusters were observed in our "See Change" program, a HST survey of 12 massive high-redshift clusters aimed at high-z supernova measurements and weak-lensing estimation of accurate cluster masses. We detect weak but significant galaxy shape distortions using IR images from the WFC3, which has not yet been used for weak-lensing studies. Both clusters appear to possess relaxed morphology in projected mass distribution, and their mass centroids agree nicely with those defined by both the galaxy luminosity and X-ray emission. Using an NFW profile, for which we assume that the mass is tightly correlated with the concentration parameter, we determine the masses of SPT-CL J2040-4451 and IDCS J1426+3508 to be M_{200}=8.6_{-1.4}^{+1.7}x10^14 M_sun and 2.2_{-0.7}^{+1.1}x10^14 M_sun, respectively. The weak-lensing mass of SPT-CLJ2040-4451 shows that the cluster is clearly a rare object. Adopting the central value, the expected abundance of such a massive cluster at z>1.48 is only ~0.07 in the parent 2500 sq. deg. survey. However, it is yet premature to claim that the presence of this cluster creates a serious tension with the current LCDM paradigm unless that tension will remain in future studies after marginalizing over many sources of uncertainties such as the accuracy of the mass function and the mass-concentration relation at the high mass end. The mass of IDCSJ1426+3508 is in excellent agreement with our previous ACS-based weak-lensing result while the much higher source density from our WFC3 imaging data makes the current statistical uncertainty ~40% smaller.Comment: Accepted to Ap

Optimising regionalisation techniques: identifying centres of endemism in the extraordinarily endemic-rich Cape Floristic Region

We used a very large dataset (>40% of all species) from the endemic-rich Cape Floristic Region (CFR) to explore the impact of different weighting techniques, coefficients to calculate similarity among the cells, and clustering approaches on biogeographical regionalisation. The results were used to revise the biogeographical subdivision of the CFR. We show that weighted data (down-weighting widespread species), similarity calculated using Kulczinsky's second measure, and clustering using UPGMA resulted in the optimal classification. This maximized the number of endemic species, the number of centres recognized, and operational geographic units assigned to centres of endemism (CoEs). We developed a dendrogram branch order cut-off (BOC) method to locate the optimal cut-off points on the dendrogram to define candidate clusters. Kulczinsky's second measure dendrograms were combined using consensus, identifying areas of conflict which could be due to biotic element overlap or transitional areas. Post-clustering GIS manipulation substantially enhanced the endemic composition and geographic size of candidate CoEs. Although there was broad spatial congruence with previous phytogeographic studies, our techniques allowed for the recovery of additional phytogeographic detail not previously described for the CFR

The minimax distortion redundancy in empirical quantizer design

We obtain minimax lower and upper bounds for the expected distortion redundancy of empirically designed vector quantizers. We show that the mean squared distortion of a vector quantizer designed from $n$ i.i.d. data points using any design algorithm is at least $\Omega (n^{-1/2})$ away from the optimal distortion for some distribution on a bounded subset of ${\cal R}^d$. Together with existing upper bounds this result shows that the minimax distortion redundancy for empirical quantizer design, as a function of the size of the training data, is asymptotically on the order of $n^{1/2}$. We also derive a new upper bound for the performance of the empirically optimal quantizer.Estimation, hypothesis testing, statistical decision theory: operations research

DEcryption Contract ENforcement Tool (DECENT): A Practical Alternative to Government Decryption Backdoors

A cryptographic contract and enforcement technology would guarantee release of a data decryption key to an authorized party if and only if predetermined contract requirements are satisfied. Threshold secret sharing can be used to eliminate the need for access to the hidden key under normal circumstances. It can also eliminate the liability and burden normally carried by device manufacturers or service providers when they store the decryption keys of their customers. Blockchain technology provides a mechanism for a public audit trail of the creation and release of the hidden key. The use of peer-to-peer mix-net network overlay technology can be added to insure that the blockchain audit trail documents the release of the key even if an all-powerful entity forces actors to act under duress

Experimental investigation of the origin of fynbos plant community structure after fire

Background and aims Species in plant communities segregate along fine-scale hydrological gradients. Although this phenomenon is not unique to fynbos, this community regenerates after fire and therefore provides an opportunity to study the ecological genesis of hydrological niche segregation. Methods Following wildfires at two field sites where we had previously mapped the vegetation and monitored the hydrology, seeds were moved experimentally in >2500 intact soil cores up and down soil-moisture gradients to test the hypothesis that hydrological niche segregation is established during the seedling phase of the life cycle. Seedling numbers and growth were then monitored and they were identified using DNA bar-coding, the first use of this technology for an experiment of this kind. Key Results At the site where niche segregation among Restionaceae had previously been found, the size of seedlings was significantly greater, the wetter the location into which they were moved, regardless of the soil moisture status of their location of origin, or of the species. Seedling weight was also significantly greater in a competition treatment where the roots of other species were excluded. No such effects were detected at the control site where niche segregation among Restionaceae was previously found to be absent. Conclusions The finding that seedling growth on hydrological gradients in the field is affected by soil moisture status and by root competition shows that hydrological niche segregation could potentially originate in the seedling stage. The methodology, applied at a larger scale and followed-through for a longer period, could be used to determine whether species are differently affected by soil moistur

Reticulation, Data Combination, and Inferring Evolutionary History: An Example from Danthonioideae (Poaceae)

We explore the potential impact of conflicting gene trees on inferences of evolutionary history above the species level. When conflict between gene trees is discovered, it is common practice either to analyze the data separately or to combine the data having excluded the conflicting taxa or data partitions for those taxa (which are then recoded as missing). We demonstrate an alternative approach, which involves duplicating conflicting taxa in the matrix, such that each duplicate is represented by one partition only. This allows the combination of all available data in standard phylogenetic analyses, despite reticulations. We show how interpretation of contradictory gene trees can lead to conflicting inferences of both morphological evolution and biogeographic history, using the example of the pampas grasses, Cortaderia. The characteristic morphological syndrome of Cortaderia can be inferred as having arisen multiple times (chloroplast DNA [cpDNA]) or just once (nuclear ribosomal DNA [nrDNA]). The distributions of species of Cortaderia and related genera in Australia/New Guinea, New Zealand, and South America can be explained by few (nrDNA) or several (cpDNA) dispersals between the southern continents. These contradictions can be explained by past hybridization events, which have linked gains of complex morphologies with unrelated chloroplast lineages and have erased evidence of dispersals from the nuclear genome. Given the discrepancies between inferences based on the gene trees individually, we urge the use of approaches such as ours that take multiple gene trees into accoun

Teleoperated visual inspection and surveillance with unmanned ground and aerial vehicles,” Int

Abstract—This paper introduces our robotic system named UGAV (Unmanned Ground-Air Vehicle) consisting of two semi-autonomous robot platforms, an Unmanned Ground Vehicle (UGV) and an Unmanned Aerial Vehicles (UAV). The paper focuses on three topics of the inspection with the combined UGV and UAV: (A) teleoperated control by means of cell or smart phones with a new concept of automatic configuration of the smart phone based on a RKI-XML description of the vehicles control capabilities, (B) the camera and vision system with the focus to real time feature extraction e.g. for the tracking of the UAV and (C) the architecture and hardware of the UAV